Device and method for measuring multi-phase fluid flow in a conduit having an abrupt gradual bend

DOEpatents

Ortiz, Marcos German

1998-01-01

A system for measuring fluid flow in a conduit having an abrupt bend. The system includes pressure transducers, one disposed in the conduit at the inside of the bend and one or more disposed in the conduit at the outside of the bend but spaced a distance therefrom. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow.

Development of a new, completely implantable intraventricular pressure meter and preliminary report of its clinical experience

NASA Technical Reports Server (NTRS)

Osaka, K.; Murata, T.; Okamoto, S.; Ohta, T.; Ozaki, T.; Maeda, T.; Mori, K.; Handa, H.; Matsumoto, S.; Sakaguchi, I.

1982-01-01

A completely implantable intracranial pressure sensor designed for long-term measurement of intraventricular pressure in hydrocephalic patients is described. The measurement principal of the device is discussed along with the electronic and component structure and sources of instrument error. Clinical tests of this implanted pressure device involving both humans and animals showed it to be comparable to other methods of intracranial pressure measurement.

Cuff for Blood-Vessel Pressure Measurements

NASA Technical Reports Server (NTRS)

Shimizu, M.

1982-01-01

Pressure within blood vessel is measured by new cufflike device without penetration of vessel. Device continuously monitors blood pressure for up to 6 months or longer without harming vessel. Is especially useful for vessels smaller than 4 or 5 millimeters in diameter. Invasive methods damage vessel wall, disturb blood flow, and cause clotting. They do not always give reliable pressure measurements over prolonged periods.

Validation of the OMRON M7 (HEM-780-E) blood pressure measuring device in a population requiring large cuff use according to the International Protocol of the European Society of Hypertension.

PubMed

El Feghali, Ramzi N; Topouchian, Jirar A; Pannier, Bruno M; El Assaad, Hiba A; Asmar, Roland G

2007-06-01

A high percentage of hypertensive patients present an arm circumference of over 32 cm; the use of a large cuff is therefore recommended. Validation studies are usually performed in the general population using a standard-size cuff. The aim of this study was to assess the accuracy of the Omron M7 device in a population with an arm circumference ranging from 32 to 42 cm. A validation study was performed according to the International Protocol of the European Society of Hypertension. This protocol is divided into two phases: the first phase is performed on 15 selected participants (45 pairs of blood-pressure measurements); if the device passes this phase, 18 supplementary participants are included (54 pairs of blood-pressure measurements), making a total number of 33 participants (99 pairs of blood-pressure measurements), on whom the analysis is performed. For each participant, four blood-pressure measurements were performed simultaneously by two trained observers, using mercury sphygmomanometers fitted with a Y tube; the measurements alternated with three by the test device. The difference between the blood-pressure value given by the device and that obtained by the two observers (mean of the two observations) was calculated for each measure. The 99 pairs of blood-pressure differences were classified into three categories (

Validation of the iHealth BP7 wrist blood pressure monitor, for self-measurement, according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Wang, Qing; Zhao, Huadong; Chen, Wan; Li, Ni; Wan, Yi

2014-02-01

The aim of this study was to validate the iHealth BP7 wireless wrist blood pressure monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010. A total of 99 pairs of test device and reference blood pressure measurements (three pairs for each of the 33 participants) were obtained for validation. The ESH-IP revision 2010 for the validation of blood pressure measuring devices in adults was followed precisely. The device produced 66, 87, and 97 measurements within 5, 10, and 15 mmHg for systolic blood pressure (SBP) and 72, 93, and 99 mmHg for diastolic blood pressure (DBP), respectively. The mean±SD device-observer difference was -0.7±6.9 mmHg for SBP and -1.0±5.1 mmHg for DBP. The number of participants with two or three device-observer differences within 5 mmHg was 25 for SBP and 26 for DBP; furthermore, there were three participants for SBP and one participant for DBP, with none of the device-observer differences within 5 mmHg. On the basis of the validation results, the iHealth BP7 wireless wrist blood pressure monitor can be recommended for self-measurement in an adult population.

Validation of Omron RS8, RS6, and RS3 home blood pressure monitoring devices, in accordance with the European Society of Hypertension International Protocol revision 2010.

PubMed

Takahashi, Hakuo; Yoshika, Masamichi; Yokoi, Toyohiko

2013-01-01

Allowing patients to measure their blood pressure at home is recognized as being of clinical value. However, it is not known how often these measurements are taken correctly. Blood pressure monitors for home use fall into two types based on the position of the cuff, ie, at the upper arm or the wrist. The latter is particularly convenient, as measurements can be taken fully clothed. This study aimed to evaluate the performance of the wrist-type blood pressure monitors Omron RS8 (HEM-6310F-E), Omron RS6 (HEM-6221-E), and Omron RS3 (HEM-6130-E). A team of three trained doctors validated the performance of these devices by comparing the measurements obtained from these devices with those taken using a standard mercury sphygmomanometer. All the devices met the validation requirements of the European Society of Hypertension International Protocol revision 2010. The difference in blood pressure readings between the tested device and the standard mercury sphygmomanometer was within 3 mmHg, which is acceptable according to the European Society of Hypertension guidelines. All the home devices tested were found to be suitable for measuring blood pressure at home because their performance fulfilled the requirement of the guidelines.

21 CFR 870.2855 - Implantable Intra-aneurysm Pressure Measurement System.

Code of Federal Regulations, 2012 CFR

2012-04-01

... System. 870.2855 Section 870.2855 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2855 Implantable Intra-aneurysm Pressure Measurement System. (a) Identification. Implantable intra...

21 CFR 870.2855 - Implantable Intra-aneurysm Pressure Measurement System.

Code of Federal Regulations, 2013 CFR

2013-04-01

... System. 870.2855 Section 870.2855 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2855 Implantable Intra-aneurysm Pressure Measurement System. (a) Identification. Implantable intra...

21 CFR 870.2855 - Implantable Intra-aneurysm Pressure Measurement System.

Code of Federal Regulations, 2014 CFR

2014-04-01

... System. 870.2855 Section 870.2855 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2855 Implantable Intra-aneurysm Pressure Measurement System. (a) Identification. Implantable intra...

An experimental abdominal pressure measurement device for child ATDs.

DOT National Transportation Integrated Search

1995-12-01

An experimental device to measure the abdominal pressure in child-size Anthropomorphic Test Dummies (ATDs) during dynamic tests was developed. A description is provided of the two ATDs in which the device was installed, the CRABI six-month-old and th...

Development of a wireless blood pressure measuring device with smart mobile device.

PubMed

İlhan, İlhan; Yıldız, İbrahim; Kayrak, Mehmet

2016-03-01

Today, smart mobile devices (telephones and tablets) are very commonly used due to their powerful hardware and useful features. According to an eMarketer report, in 2014 there were 1.76 billion smartphone users (excluding users of tablets) in the world; it is predicted that this number will rise by 15.9% to 2.04 billion in 2015. It is thought that these devices can be used successfully in biomedical applications. A wireless blood pressure measuring device used together with a smart mobile device was developed in this study. By means of an interface developed for smart mobile devices with Android and iOS operating systems, a smart mobile device was used both as an indicator and as a control device. The cuff communicating with this device through Bluetooth was designed to measure blood pressure via the arm. A digital filter was used on the cuff instead of the traditional analog signal processing and filtering circuit. The newly developed blood pressure measuring device was tested on 18 patients and 20 healthy individuals of different ages under a physician's supervision. When the test results were compared with the measurements made using a sphygmomanometer, it was shown that an average 93.52% accuracy in sick individuals and 94.53% accuracy in healthy individuals could be achieved with the new device. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Poor Reliability of Wrist Blood Pressure Self-Measurement at Home: A Population-Based Study.

PubMed

Casiglia, Edoardo; Tikhonoff, Valérie; Albertini, Federica; Palatini, Paolo

2016-10-01

The reliability of blood pressure measurement with wrist devices, which has not previously been assessed under real-life circumstances in general population, is dependent on correct positioning of the wrist device at heart level. We determined whether an error was present when blood pressure was self-measured at the wrist in 721 unselected subjects from the general population. After training, blood pressure was measured in the office and self-measured at home with an upper-arm device (the UA-767 Plus) and a wrist device (the UB-542, not provided with a position sensor). The upper-arm-wrist blood pressure difference detected in the office was used as the reference measurement. The discrepancy between office and home differences was the home measurement error. In the office, systolic blood pressure was 2.5% lower at wrist than at arm (P=0.002), whereas at home, systolic and diastolic blood pressures were higher at wrist than at arm (+5.6% and +5.4%, respectively; P<0.0001 for both); 621 subjects had home measurement error of at least ±5 mm Hg and 455 of at least ±10 mm Hg (bad measurers). In multivariable linear regression, a lower cognitive pattern independently determined both the systolic and the diastolic home measurement error and a longer forearm the systolic error only. This was confirmed by logistic regression having bad measurers as dependent variable. The use of wrist devices for home self-measurement, therefore, leads to frequent detection of falsely elevated blood pressure values likely because of a poor memory and rendition of the instructions, leading to the wrong position of the wrist. © 2016 American Heart Association, Inc.

Device and method for measuring multi-phase fluid flow and density of fluid in a conduit having a gradual bend

DOEpatents

Ortiz, M.G.; Boucher, T.J.

1998-10-27

A system is described for measuring fluid flow in a conduit having a gradual bend or arc, and a straight section. The system includes pressure transducers, one or more disposed in the conduit on the outside of the arc, and one disposed in the conduit in a straight section thereof. The pressure transducers measure the pressure of fluid in the conduit at the locations of the pressure transducers and this information is used by a computational device to calculate fluid flow rate in the conduit. For multi-phase fluid, the density of the fluid is measured by another pair of pressure transducers, one of which is located in the conduit elevationally above the other. The computation device then uses the density measurement along with the fluid pressure measurements, to calculate fluid flow. 1 fig.

Smart blood pressure holter.

PubMed

İlhan, İlhan

2018-03-01

In this study, a wireless blood pressure holter that can be used with smart mobile devices was developed. The developed blood pressure holter consists of two parts, which are a smart mobile device and a cuff. The smart mobile device is used as a recording, control and display device through a developed interface, while the cuff was designed to take measurements from the arm. Resistor-Capacitor (RC) and digital filters were used on the cuff that communicates with the smart mobile device via Bluetooth. The blood pressure was estimated using the Simple Hill Climbing Algorithm (HCA). It is possible to measure instantaneous or programmable blood pressure and heart rate values at certain intervals using this holter. The test was conducted with 30 individuals at different ages with the guidance of a specialist health personnel. The results showed that an accuracy at 93.89% and 91.95% rates could be obtained for systolic and diastolic pressure values, respectively, when compared with those obtained using a traditional sphygmomanometer. The accuracy level for the heart rate was measured as 97.66%. Furthermore, this device was tested day and night in the holter mode in terms of working time, the continuity of the Bluetooth connection and the reliability of the measurement results. The test results were evaluated separately in terms of measurement accuracy, working time, the continuity of the Bluetooth connection and the reliability of the measurement results. The measurement accuracy for systolic, diastolic blood pressure and heart rate values was obtained as 93.89%, 91.95% and 97.66%, respectively. The maximum number of measurements which can be conducted with four 1000 mA alkaline batteries at 20 min intervals was found approximately 79 (little more than 24 h). In addition, it was determined that the continuity of the Bluetooth connection and the reliability of the measurement results were automatically achieved through the features in the interface developed for the smart mobile device. These different evaluations showed that the smart blood pressure holter can meet the requirements of a classical holter device. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

21 CFR 870.2855 - Implantable Intra-aneurysm Pressure Measurement System.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Implantable Intra-aneurysm Pressure Measurement System. 870.2855 Section 870.2855 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices...

21 CFR 890.1600 - Intermittent pressure measurement system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Intermittent pressure measurement system. 890.1600 Section 890.1600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1600...

21 CFR 890.1600 - Intermittent pressure measurement system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Intermittent pressure measurement system. 890.1600 Section 890.1600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1600...

21 CFR 890.1600 - Intermittent pressure measurement system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Intermittent pressure measurement system. 890.1600 Section 890.1600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1600...

21 CFR 890.1600 - Intermittent pressure measurement system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Intermittent pressure measurement system. 890.1600 Section 890.1600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1600...

21 CFR 890.1600 - Intermittent pressure measurement system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Intermittent pressure measurement system. 890.1600 Section 890.1600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Diagnostic Devices § 890.1600...

21 CFR 870.2855 - Implantable Intra-aneurysm Pressure Measurement System.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implantable Intra-aneurysm Pressure Measurement System. 870.2855 Section 870.2855 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices...

21 CFR 870.1130 - Noninvasive blood pressure measurement system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Noninvasive blood pressure measurement system. 870.1130 Section 870.1130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1130...

Validation of the Andon KD-5917 automatic upper arm blood pressure monitor, for clinic use and self-measurement, according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Guo, Wan-Gang; Li, Bing-Ling; He, Yong; Xue, Yu-Sheng; Wang, Hai-Yan; Zheng, Qiang-Sun; Xiang, Ding-Cheng

2014-08-01

To validate the Andon KD-5917 automatic upper arm blood pressure monitor according to the European Society of Hypertension International Protocol revision 2010. Sequential same-left-arm measurements of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were obtained in 33 participants using the mercury sphygmomanometer and the test device. According to the validation protocol, 99 pairs of test device and reference blood pressure measurements (three pairs for each of the 33 participants) were obtained in the study. The device produced 73, 98, and 99 measurements within 5, 10, and 15 mmHg for SBP and 86, 98, and 99 for DBP, respectively. The mean ± SD device-observer difference was 3.07 ± 3.68 mmHg for SBP and -0.89 ± 3.72 mmHg for DBP. The number of patients with two or three of the device-observer difference within 5 mmHg was 26 for SBP and 29 for DBP, and no patient had a device-observer difference within 5 mmHg. The Andon KD-5917 automatic upper arm blood pressure monitor can be recommended for clinical use and self-measurement in an adult population on the basis of the European Society of Hypertension International Protocol revision 2010.

Pressures of Wilderness Improvised Wound Irrigation Techniques: How Do They Compare?

PubMed

Luck, John B; Campagne, Danielle; Falcón Banchs, Roberto; Montoya, Jason; Spano, Susanne J

2016-12-01

Compare the pressures measured by improvised irrigation techniques to a commercial device and to prior reports. Devices tested included a commercial 500-mL compressible plastic bottle with splash guard, a 10-mL syringe, a 10-mL syringe with a 14-ga angiocatheter (with needle removed), a 50-mL Sawyer syringe, a plastic bag punctured with a 14-ga needle, a plastic bottle with cap punctured by a 14-ga needle, a plastic bottle with sports top, and a bladder-style hydration system. Each device was leveled on a support, manually compressed, and aimed toward a piece of glass. A high-speed camera placed behind the glass recorded the height of the stream upon impact at its highest and lowest point. Measurements were recorded 5 times for each device. Pressures in pounds per square inch (psi) were calculated. The syringe and angiocatheter pressures measured the highest pressures (16-49 psi). The 50-mL syringe (7-11 psi), 14-ga punctured water bottle (7-25 psi), and water bottle with sports top (3-7 psi) all measured at or above the commercial device (4-5 psi). Only the bladder-style hydration system (1-2 psi) and plastic bag with 14-ga needle puncture (2-3 psi) did not reach pressures generated by the commercial device. Pressures are consistent with those previously reported. All systems using compressible water bottles and all syringe-based systems provided pressures at or exceeding a commercial wound irrigation device. A 14-ga punctured plastic bag and bladder-style hydration pack failed to generate similar irrigation pressures. Copyright © 2016 Wilderness Medical Society. All rights reserved.

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing.

PubMed

Donaldsson, Snorri; Falk, Markus; Jonsson, Baldvin; Drevhammar, Thomas

2015-01-01

The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates.

Imposed Work of Breathing for Flow Meters with In-Line versus Flow-Through Technique during Simulated Neonatal Breathing

PubMed Central

2015-01-01

Background The ability to determine airflow during nasal CPAP (NCPAP) treatment without adding dead space or resistance would be useful when investigating the physiologic effects of different NCPAP systems on breathing. The aim of this study was to investigate the effect on pressure stability of different flow measuring devices at the in-line and flow-through position, using simulated neonatal breathing. Methods Six different flow measure devices were evaluated by recording pressure changes and imposed work of breathing for breaths with 16 and 32 ml tidal volumes. The tests were performed initially with the devices in an in line position and with 5 and 10 L/min using flow through technique, without CPAP. The flow meters were then subsequently tested with an Infant Flow CPAP system at 3, 5 and 8 cm H2O pressure using flow through technique. The quality of the recorded signals was compared graphically. Results The resistance of the measuring devices generated pressure swings and imposed work of breathing. With bias flow, the resistance also generated CPAP pressure. Three of the devices had low resistance and generated no changes in pressure stability or CPAP pressure. The two devices intended for neonatal use had the highest measured resistance. Conclusion The importance of pressure stability and increased work of breathing during non-invasive respiratory support are insufficiently studied. Clinical trials using flow-through technique have not focused on pressure stability. Our results indicate that a flow-through technique might be a way forward in obtaining a sufficiently high signal quality without the added effects of rebreathing and increased work of breathing. The results should stimulate further research and the development of equipment for dynamic flow measurements in neonates. PMID:26192188

Validation of the YuWell YE690A upper-arm blood pressure monitor, for clinic use and self-measurement, according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Chen, Qi; Lei, Lei; Li, Yan; Wang, Ji-Guang

2017-10-01

The present study aimed to evaluate the accuracy of the automated oscillometric upper-arm blood pressure monitor YuWell YE690A for blood pressure measurement according to the International Protocol of the European Society of Hypertension revision 2010. Systolic and diastolic blood pressures were measured sequentially in 33 adult Chinese (12 women, 44.2 years of mean age) using a mercury sphygmomanometer (two observers) and the YE690A device (one supervisor). A total of 99 pairs of comparisons were obtained from 33 participants for judgments in two parts with three grading phases. All the blood pressure requirements were fulfilled. The YuWell YE690A device achieved the targets in part 1 of the validation study. The number of absolute differences between device and observers within 5, 10, and 15 mmHg was 79/99, 96/99, and 97/99, respectively, for systolic blood pressure and 72/99, 95/99, and 98/99, respectively, for diastolic blood pressure. The device also fulfilled the criteria in part 2 of the validation study. Thirty-one and 25 participants for systolic and diastolic blood pressure, respectively, had at least two of the three device-observer differences within 5 mmHg (required ≥24). No participant for systolic and two participants for diastolic blood pressure had all the three device-observer comparisons greater than 5 mmHg. The YuWell blood pressure monitor YE690A has passed the requirements of the International Protocol revision 2010 and hence can be recommended for blood pressure measurement in adults.

21 CFR 862.2730 - Osmometer for clinical use.

Code of Federal Regulations, 2013 CFR

2013-04-01

...) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862... to measure the osmotic pressure of body fluids. Osmotic pressure is the pressure required to prevent... device are used in the diagnosis and treatment of body fluid disorders. (b) Classification. Class I...

21 CFR 862.2730 - Osmometer for clinical use.

Code of Federal Regulations, 2011 CFR

2011-04-01

...) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862... to measure the osmotic pressure of body fluids. Osmotic pressure is the pressure required to prevent... device are used in the diagnosis and treatment of body fluid disorders. (b) Classification. Class I...

21 CFR 862.2730 - Osmometer for clinical use.

Code of Federal Regulations, 2012 CFR

2012-04-01

...) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862... to measure the osmotic pressure of body fluids. Osmotic pressure is the pressure required to prevent... device are used in the diagnosis and treatment of body fluid disorders. (b) Classification. Class I...

21 CFR 862.2730 - Osmometer for clinical use.

Code of Federal Regulations, 2014 CFR

2014-04-01

...) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Laboratory Instruments § 862... to measure the osmotic pressure of body fluids. Osmotic pressure is the pressure required to prevent... device are used in the diagnosis and treatment of body fluid disorders. (b) Classification. Class I...

Noise trauma induced by a mousetrap--sound pressure level measurement of vole captive bolt devices.

PubMed

Frank, Matthias; Napp, Matthias; Lange, Joern; Grossjohann, Rico; Ekkernkamp, Axel; Beule, Achim G

2010-05-01

While ballistic parameters of vole captive bolt devices have been reported, there is no investigation on their hazardous potential to cause noise trauma. The aim of this experimental study was to measure the sound pressure levels of vole captive bolt devices. Two different shooting devices were examined with a modular precision sound level meter on an outdoor firing range. Measurements were taken in a semi-circular configuration with measuring points 0 degrees in front of the muzzle, 90 degrees at right angle of the muzzle, and 180 degrees behind the shooting device. Distances between muzzle and microphone were 0.5, 1, 2, 10, and 20 m. Sound pressure levels exceeded 130 dB(C) at any measuring point within the 20-m area. Highest measurements (more than 172 dB[C]) were taken in the 0 degrees direction at the 0.5-m distance for both shooting devices proving the hazardous potential of these gadgets to cause noise trauma.

Trial of validation of two devices for self-measurement of blood pressure according to the European Society of Hypertension International Protocol: the Citizen CH-432B and the Citizen CH-656C.

PubMed

Cotte, Uwe V; Faltenbacher, Verena H; von Willich, Werner; Bogner, Johannes R

2008-02-01

Two devices for self-measurement of blood pressure, one at the upper arm (Citizen CH-432B) and one at the wrist (Citizen CH-656C), were evaluated according to the International Protocol of the European Society of Hypertension. The International Protocol is divided into two phases: the first phase is performed on 15 selected participants with five participants in three different blood pressure ranges. If the devices passed this phase, 18 additional participants selected on the basis of the same criteria as in phase 1 were included. Two skilled observers performed the following blood pressure measurements: five measurements were performed with the mercury standard alternating with four measurements with each of the test devices per participant. The first measurement result from each device instrument was not included in the analysis. The difference between the blood pressure value given by the devices and that obtained by the two observers (mean of the two observers) was calculated for each pair of measurements and classified into three categories (within 5, 10 and 15 mmHg). The results were compared to the pass criteria established by the European Society of Hypertension. Afterwards the number of measurement differences falling within 5 mmHg was determined for every person. At least 22 of the 33 participants should have two of their three comparisons within 5 mmHg and there should be a maximum of three participants without a measurement difference within the 5 mmHg range. Both tested devices passed the first phase of the validation process by exceeding the required number of comparisons falling within the 5, 10 and 15 mmHg error zones. Even the second phase confirmed the validation criteria with average differences between the device and the mercury sphygmomanometer of 0.7+/-4.4 and -3.6+/-4.0 mmHg for systolic blood pressure and diastolic blood pressure, respectively, for the Citizen CH-432B device and -0.7+/-6.0 and -1.2+/-4.5 mmHg for the Citizen CH-656C device. Phase 2 contains furthermore an individual analysis of the 33 participants, the requirements of which were also fulfilled by both devices. The Citizen CH-432B and the Citizen CH-656C devices pass the validation recommendations of the International Protocol. They can be recommended for clinical use.

Prospective clinical study to evaluate an oscillometric blood pressure monitor in pet rabbits.

PubMed

Bellini, Luca; Veladiano, Irene A; Schrank, Magdalena; Candaten, Matteo; Mollo, Antonio

2018-02-27

Rabbits are particularly sensitive to develop hypotension during sedation or anaesthesia. Values of systolic or mean non-invasive arterial blood pressure below 80 or 60 mmHg respectively are common under anaesthesia despite an ongoing surgery. A reliable method of monitoring arterial blood pressure is extremely important, although invasive technique is not always possible due to the anatomy and dimension of the artery. The aim of this study was to evaluate the agreement between a new oscillometric device for non-invasive arterial blood pressure measurement and the invasive method. Moreover the trending ability of the device, ability to identify changes in the same direction with the invasive methods, was evaluated as well as the sensibility of the device in identifying hypotension arbitrarily defined as invasive arterial blood pressure below 80 or 60 mmHg. Bland-Altman analysis for repeated measurements showed a poor agreement between the two methods; the oscillometric device overestimated the invasive arterial blood pressure, particularly at high arterial pressure values. The same analysis repeated considering oscillometric measurement that match invasive mean pressure lower or equal to 60 mmHg showed a decrease in biases and limits of agreement between methods. The trending ability of the device, evaluated with both the 4-quadrant plot and the polar plot was poor. Concordance rate of mean arterial blood pressure was higher than systolic and diastolic pressure although inferior to 90%. The sensibility of the device in detecting hypotension defined as systolic or mean invasive arterial blood pressure lower than 80 or 60 mmHg was superior for mean oscillometric pressure rather than systolic. A sensitivity of 92% was achieved with an oscillometric measurement for mean pressure below 65 mmHg instead of 60 mmHg. Non-invasive systolic blood pressure is less sensitive as indicator of hypotension regardless of the cutoff limit considered. Although mean invasive arterial blood pressure is overestimated by the device, the sensitivity of this non-invasive oscillometric monitor in detecting invasive mean pressure below 60 mmHg is acceptable but a cutoff value of 65 mmHg needs to be used.

Development of a cuffless blood pressure measurement system.

PubMed

Shyu, Liang-Yu; Kao, Yao-Lin; Tsai, Wen-Ya; Hu, Weichih

2012-01-01

This study constructs a novel blood pressure measurement device without the air cuff to overcome the problem of discomfort and portability. The proposed device measures the blood pressure through a mechanism that is made of silicon rubber and pressure transducer. The system uses a microcontroller to control the measurement procedure and to perform the necessary computation. To verify the feasibility of the constructed device, ten young volunteers were recruited. Ten blood pressure readings were obtained using the new system and were compared with ten blood pressure readings from bedside monitor (Spacelabs Medical, model 90367). The results indicated that, when all the readings were included, the mean pressure, systolic pressure and diastolic pressure from the new system were all higher than those from bedside monitor. The correlation coefficients between these two were 0.15, 0.18 and 0.29, for mean, systolic and diastolic pressures, respectively. After excluding irregular apparatus utilization, the correlation coefficient increased to 0.71, 0.60 and 0.41 for diastolic pressure, mean pressure and systolic pressure, respectively. We can conclude from these results that the accuracy can be improved effectively by defining the user regulation more precisely. The above mentioned irregular apparatus utilization factors can be identified and eliminated by the microprocessor to provide a reliable blood pressure measurement in practical applications in the future.

Comparison of three portable instruments to measure compression pressure.

PubMed

Partsch, H; Mosti, G

2010-10-01

Measurement of interface pressure between the skin and a compression device has gained practical importance not only for characterizing the efficacy of different compression products in physiological and clinical studies but also for the training of medical staff. A newly developed portable pneumatic pressure transducer (Picopress®) was compared with two established systems (Kikuhime® and SIGaT tester®) measuring linearity, variability and accuracy on a cylindrical model using a stepwise inflated sphygmomanometer as the reference. In addition the variation coefficients were measured by applying the transducers repeatedly under a blood pressure cuff on the distal lower leg of a healthy human subject with stepwise inflation. In the pressure range between 10 and 80 mmHg all three devices showed a linear association compared with the sphygmomanometer values (Pearson r>0.99). The best reproducibility (variation coefficients between 1.05-7.4%) and the highest degree of accuracy demonstrated by Bland-Altman plots was achieved with the Picopress® transducer. Repeated measurements of pressure in a human leg revealed average variation coefficients for the three devices of 4.17% (Kikuhime®), 8.52% (SIGaT®) and 2.79% (Picopress®). The results suggest that the Picopress® transducer, which also allows dynamic pressure tracing in connection with a software program and which may be left under a bandage for several days, is a reliable instrument for measuring the pressure under a compression device.

40 CFR 60.403 - Monitoring of emissions and operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... measurement of the pressure loss of the gas stream through the scrubber. The monitoring device must be certified by the manufacturer to be accurate within ±250 pascals (±1 inch water) gauge pressure. (2) A monitoring device for the continuous measurement of the scrubbing liquid supply pressure to the control...

Development of an electronic manometer for intrapleural pressure monitoring.

PubMed

Krenke, Rafał; Guć, Maciej; Grabczak, Elżbieta Magdalena; Michnikowski, Marcin; Pałko, Krzysztof Jakub; Chazan, Ryszarda; Gólczewski, Tomasz

2011-01-01

Measurement of intrapleural pressure is useful during various pleural procedures. However, a pleural manometer is rarely available. The aim of this study was to (1) construct an electronic pleural manometer, (2) assess the accuracy of the measurements done with the new device, (3) calculate the costs of the manometer construction and (4) perform an initial evaluation of the device in a clinical setting. Only widely accessible elements were used to construct the device. A vascular pressure transducer was used to transform pressure into an electronic signal. Reliability of the measurements was evaluated in a laboratory setting in a prospective, single-blind manner by comparing the results with those measured by a water manometer. Functionality of the device was assessed during therapeutic thoracentesis. The cost of the new pleural manometer was calculated. We built a small, portable device which can precisely measure intrapleural pressure. The measurement results showed very high agreement with those registered with a water manometer (r = 0.999; p < 0.001). The initial evaluation of the electronic manometer during therapeutic thoracentesis showed it was easy to use. The total time needed for 6 measurements after withdrawal of different volumes of pleural fluid in 1 patient did not exceed 6 min. The total cost of the device was calculated to be <2,000 EUR. In the face of very limited offer of commercially available pleural manometers, it is possible to successfully construct a self-made, reliable, electronic pleural manometer at modest costs. The device is easy to use and enables data display and storage in the personal computer. Copyright © 2011 S. Karger AG, Basel.

An underwater blood pressure measuring device.

PubMed

Sieber, Arne; Kuch, Benjamin; L'abbate, Antonio; Wagner, Matthias; Dario, Paolo; Bedini, Remo

2008-09-01

Measurement of arterial blood pressure is an important vital sign for monitoring the circulation. However, up to now no instrument has been available that enables the measurement of blood pressure underwater. The present paper details a novel, oscillometric, automatic digital blood pressure (BP) measurement device especially designed for this purpose. It consists mainly of analogue and digital electronics in a lexan housing that is rated to a depth of up to 200 metres' sea water, a cuff and a solenoid for inflation of the cuff with air supplied from a scuba tank. An integrated differential pressure sensor, exposed to the same ambient pressure as the cuff, allows accurate BP measurement. Calculation of systolic and diastolic pressures is based on the analysis of pressure oscillations recorded during the deflation. In hyperbaric chamber tests to pressures up to 405 kPa, BP measurements taken with the prototype were comparable to those obtained with established manual and automated methods. Swimming pool tests confirmed the correct functioning of the system underwater. The quality of the recorded pressure oscillations was very good even at 10 metres' fresh water, and allowed determination of diastolic and systolic pressure values. Based on these results we envisage that this device will lead to a better understanding of human cardiovascular physiology in underwater and hyperbaric environments.

Stand Alone Pressure Measurement Device (SAPMD) for the space shuttle Orbiter, part 2

NASA Technical Reports Server (NTRS)

Tomlinson, Bill

1989-01-01

The Stand Alone Pressure Measurement Device (SAPMD) specifications are examined. The HP.SAPMD GSE software is listed; the HP/SGA readme program is presented; and the SPMD acceptance test procedure is described.

Validation of the Andon KD-5851 upper arm blood pressure monitor, for self-measurement according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Wu, Lili; Jiao, Yinghui; Wang, Chengdong; Chen, Lei; Di, Dalin; Zhang, Haiyan

2015-08-01

This study aimed to validate the Andon KD-5851 upper arm blood pressure (BP) monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010. A total of 33 eligible participants were included in the study. Sequential measurements of BPs were performed using a mercury sphygmomanometer and the device, and the data analysis was carried out following precisely the ESH-IP revision 2010. The device had 82, 98, and 99 measurements within 5, 10, and 15 mmHg for systolic blood pressure and 85, 95, and 99 measurements for diastolic blood pressure, respectively. The average device-observer difference was -0.53±4.00 mmHg for systolic blood pressure and -1.15±4.06 mmHg for diastolic blood pressure. The device passed all the criteria according to the ESH-IP revision 2010. According to the validation results on the basis of the ESH-IP revision 2010, the Andon KD-5851 upper arm BP monitor can be recommended for self/home measurement in adults. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Validation of the Samsung SBM-100A and Microlife BP 3BU1-5 wrist blood pressure measuring devices in adults according to the International Protocol.

PubMed

Altunkan, Sekip; Ilman, Nevzat; Altunkan, Erkan

2007-04-01

A variety of automatic blood measurement devices with diverse features have been introduced to the medical markets recently. Among these devices, models that measure at the wrist have become increasingly popular in self measurements. The objective of this study was to evaluate the accuracy of the Samsung SBM-100A and Microlife BP 3BU1-5 wrist blood pressure devices against the mercury sphygmomanometer in adults according to the International Protocol criteria. Fifty-four patients over 30 years of age were studied and classified based on the International Protocol range. Blood pressure measurements at the wrist with the Samsung SBM-100A and Microlife BP 3BU1-5 were compared with the results obtained by two trained observers using a mercury sphygmomanometer. Nine sequential blood pressure measurements were taken. A total of 33 participants with randomly distributed arm circumferences were selected for both of the validation studies. During each validation study, 99 measurements were obtained for comparison from 33 participants. The first phase was performed on 15 participants and if the device passed this phase, 18 more participants were selected. Mean discrepancies and standard deviations of the device-sphygmomanometer were 0.9+/-9.2 and -2.7+/-9.3 mmHg for systolic blood pressure and -1.4+/-8.0 mmHg and 1.4+/-5.7 for diastolic blood pressure in the Samsung and Microlife study groups, respectively. The Samsung SBM-100A passed Phase 1 in 15 participants. Despite the fact that Microlife BP 3BU1-5 passed Phase 1 for diastolic pressure, it failed according to the systolic pressure criteria. Eighteen patients were added and Phase 2 was continued, in which Samsung SBM-100A failed to meet the criteria of Phases 2.1 and 2.2 for adults in systolic and diastolic blood pressure. It was found that the Microlife BP 3BU1-5 does not meet the criteria of either of Phases 2.1 and 2.2 for systolic blood pressure and Phase 2.2 for diastolic blood pressure. In this study, Samsung SBM-100A and Microlife blood pressure 3BU1-5 wrist blood pressure monitoring devices were found to be incompetent to meet the criteria of the International Protocol and it has not been possible to suggest any one of them for clinical use in adults.

[A design and study of a novel electronic device for cuff-pressure monitoring].

PubMed

Wang, Shupeng; Li, Wei; Li, Wen; Song, Dejing; Chen, Desheng; Duan, Jun; Li, Chen; Li, Gang

2017-06-01

To design a novel electronic device for measuring the pressure in the cuff of the artificial airway; and to study the advantage of this device on continuous and intermittent cuff pressure monitoring. (1) a portable electronic device for cuff pressure measurement was invented, which could turn pressure signal into electrical signal through a pressure transducer. Meantime, it was possible to avoid pressure leak from the joint and the inside of the apparatus by modified Luer taper and sophisticated design. If the cuff pressure was out of the normal range, the apparatus could release a sound and light alarm. (2) Six traditional mechanical manometers were used to determine the cuff pressure in 6 tracheal tubes. The cuff pressure was maintain at 30 cmH 2 O (1 cmH 2 O = 0.098 kPa) by the manometer first, and repeated every 30 seconds for 4 times. (3) Study of continuous cuff pressure monitoring: We used a random number generator to randomize 6 tracheal tubes, 6 mechanical manometers and 6 our products by number 1-6, which has the same number of a group. Every group was further randomized into two balanced groups, one group used the mechanical manometer first, and the other used our product first. The baseline pressure was 30 cmH 2 O, measurement was performed every 4 hours for 6 times. When traditional mechanical manometer was used for cuff pressure monitoring, cuff pressure was decreased by an average of 2.9 cmH 2 O for each measurement (F = 728.2, P = 0.000). In study of continually monitoring, at each monitoring point, the pressure measured by electronic manometer was higher than the mechanical manometer. All the pressures measured by mechanical manometer were dropped below 20 cmH 2 O at 8th hour, and there was no pressure decrease below 20 cmH 2 O measured by electronic manometer in 24 hours by contrast. In study of intermittent monitoring, the same result was found. The pressure was dropped significantly with time when measured by mechanical manometer (F = 61.795, P = 0.000), the drops below 20 cmH 2 O began at 8th hour; but when measured by electronic manometer, all the value stayed unchanged around the baseline in 24 hours (F = 0.511, P = 0.796). Compared with traditional mechanical manometer, cuff pressures monitored by our novel electronic manometer were steadier in both continuous and intermittent monitoring. The device is compact and convenient, and can provide a good solution for continuously monitor of the tracheal cuff pressure.

21 CFR 870.2850 - Extravascular blood pressure transducer.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Extravascular blood pressure transducer. 870.2850... blood pressure transducer. (a) Identification. An extravascular blood pressure transducer is a device used to measure blood pressure by changes in the mechanical or electrical properties of the device. The...

21 CFR 870.2850 - Extravascular blood pressure transducer.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Extravascular blood pressure transducer. 870.2850... blood pressure transducer. (a) Identification. An extravascular blood pressure transducer is a device used to measure blood pressure by changes in the mechanical or electrical properties of the device. The...

21 CFR 870.2850 - Extravascular blood pressure transducer.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Extravascular blood pressure transducer. 870.2850... blood pressure transducer. (a) Identification. An extravascular blood pressure transducer is a device used to measure blood pressure by changes in the mechanical or electrical properties of the device. The...

Validation of the mobil-O-Graph: 24 h-blood pressure measurement device.

PubMed

Wei, Wolfgang; Tölle, Markus; Zidek, Walter; van der Giet, Markus

2010-08-01

Twenty-four-hour blood pressure measurement is of importance not only in the detection of hypertension but also in the detection of blood pressure changes in hypertensive and nonhypertensives over the day to identify, for example, nondipper hypertensives. This study describes the validation of the mobil-O-Graph according to the criteria of the British Hypertension Society (BHS). For each patient three readings obtained by the mobil-O-Graph were compared with auscultatory sphygmomanometric readings obtained by two trained clinicians. The sphygmomanometric reference measurements were alternated with the readings obtained by the device. Eighty-five patients (mean age 53.4+/-18.4 years) were recruited for the BHS protocol. Differences between blood pressure values of the test device and the mercury reading were calculated for each measurement. In the BHS validation procedure the mean differences of the observer readings and the test device were -2.2+/-6.7 (systolic) and -0.6+/-5.6 mmHg (diastolic) for observer 1 and -2.2+/-7.3 mmHg (systolic) and-0.4+/-6.1 mmHg (diastolic) for observer 2. The device achieved grade A for systolic and diastolic blood pressure for both the observers 1 and 2 leading to a final grade A/A. According to the BHS protocol the measurements of the device have to be considered 'very accurate and with no error of clinical relevance'. The device met the accuracy requirements of the BHS standard and can be recommended for clinical use.

Validation of the iHealth BP3 upper-arm blood pressure monitor, for clinic use and self-measurement, according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Chen, Can; Shang, Fujun; Wang, Jiepin; Chen, Jianghong; Ji, Na; Wan, Yi

2012-12-01

This study aimed to evaluate the performance of the iHealth BP3 upper-arm blood pressure monitor, which is designed for clinic use and self-measurement of blood pressure using Apple touch devices as an interface. The European Society of Hypertension International Protocol (ESH-IP) revision 2010 for the validation of blood pressure measuring devices in adults was followed precisely. Ninty-nine couples of test device and reference blood pressure measurements were obtained during the study (three pairs for each of the 33 participants). The 33 participants, age 47.1±12.3 years (age range 27-69 years) and arm circumference 30.0±4.4 cm, had a mean systolic blood pressure (SBP) of 143.9±27.4 mmHg and a mean diastolic blood pressure (DBP) of 90.1±18.3 mmHg. The device passed all of the requirements fulfilling the standards of the protocol, and the mean±SD device-observer difference was 2.8±4.2 mmHg for SBP and -0.4±3.5 mmHg for DBP. According to the results of the validation study on the basis of the ESH-IP revision 2010, the iHealth BP3 can be recommended for clinic use and self-measurement in an adult population. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Dynamic pressure measurement of cartridge operated vole captive bolt devices.

PubMed

Frank, M; Philipp, K P; Franke, E; Frank, N; Bockholdt, B; Grossjohann, R; Ekkernkamp, A

2009-01-10

Vole captive bolt devices are powder actuated spring guns that are used as a pest control mean. After having triggered the explosion of the blank cartridge by touching a metal ring around the muzzle, the vole is killed by the massive propulsion of the gas jet. Improper use and recklessness while handling these devices may cause severe injuries with the hand of the operator at particular risk. Currently, there are no experimental investigations on the ballistic background of these devices. An experimental test set-up was designed for measurement of the firing pressure and the dynamic force of the gas jet of a vole captive bolt device. Therefore, a vole captive bolt device was prepared with a pressure take-off channel and a piezoelectric transducer for measurement of the firing pressure. For measurement of the dynamic impact force of the gas jet an annular quartz force sensor was installed on a test bench. Each three simultaneous measurements of the cartridges' firing pressure and the dynamic force of the blast wave were taken at various distances between muzzle and load washer. The maximum gas pressure in the explosion chamber was up to 1100 bar. The shot development over time showed a typical gas pressure curve. Flow velocity of the gas jet was up to 2000 m/s. The maximum impact force of the gas jet at the target showed a strong inverse ratio to the muzzle's distance and was up to 11,500 N for the contact shot distance. Energy density of the gas jet for the close contact shot was far beyond the energy density required for skin penetration. The unique design features (short tube between cartridge mouth and muzzle and narrow diameter of the muzzle) of these gadgets are responsible for the high firing pressure, velocity and force of the gas jet. These findings explain the trauma mechanics of the extensive tissue damage observed in accidental shots of these devices.

Validation of Transtek blood pressure monitor TMB-1491 for self-measurement according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Tian, Huiyong; Zeng, Sijian; Zhong, Xiaoyan; Gong, Wei; Liu, Wenjun

2015-10-01

Transtek blood pressure monitor TMB-1491 is an automatic upper arm device designed for self/home measurement in adult populations. This study aimed to evaluate its accuracy according to the European Society of Hypertension International Protocol revision 2010. The protocol requirements were followed precisely with the recruitment of 33 adult individuals on whom same-left-arm sequential systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured. According to the validation protocol, 99 pairs of test device and reference blood pressure measurements were obtained in this study (three pairs for each of the 33 participants). The device produced 74, 95 and 99 measurements within 5, 10, and 15 mmHg for SBP and 85, 97, and 99 for DBP, respectively. The mean±SD device-observer difference was -0.6±4.4 mmHg for SBP and -0.6±3.4 mmHg for DBP. The number of participants with two or three device-observer difference within 5 mmHg was 24 for SBP and 29 for DBP. In addition, none of the participants had a device-observer difference within 5 mmHg for SBP, and three of the participants had the same for DBP. Transtek TMB-1491 has passed all phases of European Society of Hypertension International Protocol revision 2010 and can be recommended for self/home measurement in adult populations.

A bio-telemetric device for measurement of left ventricular pressure-volume loops using the admittance technique in conscious, ambulatory rats.

PubMed

Raghavan, Karthik; Feldman, Marc D; Porterfield, John E; Larson, Erik R; Jenkins, J Travis; Escobedo, Daniel; Pearce, John A; Valvano, Jonathan W

2011-06-01

This paper presents the design, construction and testing of a device to measure pressure-volume loops in the left ventricle of conscious, ambulatory rats. Pressure is measured with a standard sensor, but volume is derived from data collected from a tetrapolar electrode catheter using a novel admittance technique. There are two main advantages of the admittance technique to measure volume. First, the contribution from the adjacent muscle can be instantaneously removed. Second, the admittance technique incorporates the nonlinear relationship between the electric field generated by the catheter and the blood volume. A low power instrument weighing 27 g was designed, which takes pressure-volume loops every 2 min and runs for 24 h. Pressure-volume data are transmitted wirelessly to a base station. The device was first validated on 13 rats with an acute preparation with 2D echocardiography used to measure true volume. From an accuracy standpoint, the admittance technique is superior to both the conductance technique calibrated with hypertonic saline injections, and calibrated with cuvettes. The device was then tested on six rats with 24 h chronic preparation. Stability of animal preparation and careful calibration are important factors affecting the success of the device.

Bio-telemetric device for measurement of left ventricular pressure-volume loops using the admittance technique in conscious, ambulatory rats

PubMed Central

Raghavan, Karthik; Feldman, Marc D; Porterfield, John E; Larson, Erik R; Jenkins, J Travis; Escobedo, Daniel; Pearce, John A

2011-01-01

This paper presents the design, construction and testing of a device to measure pressure volume loops in the left ventricle of conscious, ambulatory rats. Pressure is measured with a standard sensor, but volume is derived from data collected from a tetrapolar electrode catheter using a novel admittance technique. There are two main advantages of the admittance technique to measure volume. First, the contribution from the adjacent muscle can be instantaneously removed. Second, the admittance technique incorporates the nonlinear relationship between the electric field generated by the catheter and the blood volume. A low power instrument weighing 27 g was designed, which takes pressure-volume loops every 2 minutes and runs for 24 hours. Pressure-volume data are transmitted wirelessly to a base station. The device was first validated in thirteen rats with an acute preparation with 2-D echocardiography used to measure true volume. From an accuracy standpoint, the admittance technique is superior to both the conductance technique calibrated with hypertonic saline injections, and calibrated with cuvettes. The device was then tested in six rats with a 24-hour chronic preparation. Stability of the animal preparation and careful calibration are important factors affecting the success of the device. PMID:21606560

Validation of the Beneware model ABP-021 ambulatory blood pressure monitor according to the revised 2010 European Society of hypertension international protocol.

PubMed

Pereira, Telmo; Guimarães, João

2018-06-11

This study aimed to evaluate the accuracy of the Beneware model ABP-021 oscillometric blood pressure monitor in the general population according to the European Society of Hypertension International Protocol (ESH-IP). The accuracy of the device was assessed in relation to various clinical variables, including age, sex, BMI, and arm circumference. Thirty-three individuals (18 men and 15 women), with a mean age of 36±14 years (age range: 20-68 years), were studied according to the recommendations of the ESH-IP. Sequential same-arm blood pressure measurements were performed, alternating between a mercury standard and the automatic device. The differences among the test-control measurements were assessed and divided into categorization zones of 5, 10, and 15 mmHg discrepancy. The device complied with the quality requirements of the ESH-IP. The device-observer disagreement was -1.2±4.7 mmHg for systolic blood pressure (SBP) and -1.7±4.3 mmHg for diastolic blood pressure (DBP). The device produced 77, 93, and 98 measurements, respectively, within the 5, 10, and 15 mmHg discrepancy limits for SBP. For DBP, 80, 97, and 99 measurements were observed within the 5, 10, and 15 mmHg discrepancy limits. The number of participants with two or three of the device-observer differences within 5 mmHg was 26 for SBP and 29 for DBP, whereas there were only two participants with no device-observer differences within 5 mmHg for DBP. These data show that the Beneware model ABP-021 monitor meets the requirements of the ESH-IP, in static conditions, indicating its suitability for measuring blood pressure in the general adult population.

Development of a wearable plantar force measurement device for gait analysis in remote conditions.

PubMed

Hamid, Rawnak; Wijesundara, Suharshani; McMillan, Lachlan; Scott, David; Redoute, Jean-Michel; Ebeling, Peter R; Yuce, Mehmet Rasit

2017-07-01

The pressure field that exists between the foot and the supporting surface is identified as the foot plantar pressure. The information obtained from foot plantar pressure measurements has useful applications that include diagnosis of gait disturbances, optimization of footwear design, sport biomechanics and prevention of injury. Using wearable technology to measure foot plantar pressure continuously allows the collection of comprehensive real-life data sets while interfering minimally with the subject's daily activities. This paper presents the design of a wearable device to measure foot plantar pressure. Mechanical and electrical design considerations as well as data analysis are discussed. A pilot study involving 20 physically fit volunteers (15 males and 5 females, ageing from 20 - 45) performing a variety of physical activities (such as standing, walking, jumping and climbing up and down stairs) illustrate the potential of the device in terms of its wearability, and suitability for unobtrusive long-term monitoring.

Multi-channel electronically scanned cryogenic pressure sensor

NASA Technical Reports Server (NTRS)

Chapman, John J. (Inventor); Hopson, Purnell, Jr. (Inventor); Kruse, Nancy M. H. (Inventor)

1995-01-01

A miniature, multi-channel, electronically scanned pressure measuring device uses electrostatically bonded silicon dies in a multielement array. These dies are bonded at specific sites on a glass, prepatterned substrate. Thermal data is multiplexed and recorded on each individual pressure measuring diaphragm. The device functions in a cryogenic environment without the need of heaters to keep the sensor at constant temperatures.

Evaluation of the overall efficacy of the Omron office digital blood pressure HEM-907 monitor in adults.

PubMed

White, W B; Anwar, Y A

2001-04-01

Non-invasive self blood pressure monitoring has become increasingly popular. To assure the accuracy of devices used for this purpose, all need to be validated independently prior to marketing. The objective of this study was to assess the accuracy of the HEM-907, a new semi-automatic, non-invasive, oscillometric blood pressure monitoring device specifically designed to be used in the clinic or physician's office setting. Blood pressure measurements taken employing this device were compared with the results obtained by two experienced observers using a mercury sphygmomanometer on 100 subjects and patients (384 measurements). The limits of agreement were calculated for the device compared with the results of the two observers according to the standards of the Association for the Advancement of Medical Instrumentation (AAMI). The agreement between the two observers was -0.36+/-2.32mmHg for systolic blood pressure and 0.02+/-2.42mmHg for diastolic blood pressure. The agreement between the device and the observers was 1.56+/-4.42mmHg and 3.49+/-4.61mmHg for systolic and diastolic blood pressure respectively. The Omron HEM-907 satisfied the AAMI criteria for accuracy for a non-invasive blood pressure monitoring device.

Validation of the custo screen pediatric blood pressure monitor according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Beime, Beate; Deutsch, Cornelia; Krüger, Ralf; Wolf, Andreas; Müller, Peter; Hammel, Gertrud; Bramlage, Peter

2017-05-01

The purpose of the study was to validate the ambulatory blood pressure monitoring (ABPM) device custo screen pediatric in children aged 3 to 12 years according to the International Protocol of the European Society of Hypertension (ESH-IP revision 2010). Thirty-three children were included and systolic and diastolic blood pressure measurements were performed according to the ESH-IP. The protocol was modified for children considering data from the German Health Interview and Examination Survey for Children and Adolescents (KIGGS). The custo screen pediatric met all the requirements of the ESH-IP. The mean difference between the test device and the reference was -1.4 ± 3.0 mmHg for systolic blood pressure (SBP) and -0.7 ± 3.2 mmHg for diastolic blood pressure (DBP). For SBP and DBP, all 99 measurements were within the absolute difference of 10 mmHg between the test device and the reference. As to part 2 of the protocol, for DBP in all subjects, two out of three measurements were within 5 mmHg between the device and the standard, whereas for SBP in 32 of 33 subjects, two out of three measurements were within this range. The custo screen pediatric met all criteria of the ESH-IP review 2010, modified for children from 3 to about 12 years, and can be recommended for ABPM in children. What is Known: • Validation of blood pressure measuring devices is essential to provide patients with an accurate blood pressure measuring device. • The majority of devices has not been validated in children. What is New: • Prior to the present validation, study protocol adjustments of ESH-IP review 2010 for children were defined according to German Health Interview and Examination Survey for Children and Adolescents 2013 (KIGGS). • The custo screen pediatric test device met all criteria of ESH-IP revision 2010, modified for children, and can be recommended for ABPM in children aged 3 to about 12 years.

Acoustic force measurements on polymer-coated microbubbles in a microfluidic device

PubMed Central

Memoli, Gianluca; Fury, Christopher R.; Baxter, Kate O.; Gélat, Pierre N.; Jones, Philip H.

2017-01-01

This work presents an acoustofluidic device for manipulating coated microbubbles, designed for the simultaneous use of optical and acoustical tweezers. A comprehensive characterization of the acoustic pressure in the device is presented, obtained by the synergic use of different techniques in the range of acoustic frequencies where visual observations showed aggregation of polymer-coated microbubbles. In absence of bubbles, the combined use of laser vibrometry and finite element modelling supported a non-invasive measurement of the acoustic pressure and an enhanced understanding of the system resonances. Calibrated holographic optical tweezers were used for direct measurements of the acoustic forces acting on an isolated microbubble, at low driving pressures, and to confirm the spatial distribution of the acoustic field. This allowed quantitative acoustic pressure measurements by particle tracking, using polystyrene beads, and an evaluation of the related uncertainties. This process facilitated the extension of tracking to microbubbles, which have a negative acoustophoretic contrast factor, allowing acoustic force measurements on bubbles at higher pressures than optical tweezers, highlighting four peaks in the acoustic response of the device. Results and methodologies are relevant to acoustofluidic applications requiring a precise characterization of the acoustic field and, in general, to biomedical applications with microbubbles or deformable particles. PMID:28599556

Ultrasonic Apparatus and Technique to Measure Changes in Intracranial Pressure

NASA Technical Reports Server (NTRS)

Yost, William T. (Inventor); Cantrell, John H. (Inventor)

2002-01-01

Changes in intracranial pressure can be measured dynamically and non-invasively by monitoring one or more cerebrospinal fluid pulsatile components. Pulsatile components such as systolic and diastolic blood pressures are partially transferred to the cerebrospinal fluid by way of blood vessels contained in the surrounding brain tissue and membrane. As intracranial pressure varies these cerebrospinal fluid pulsatile components also vary. Thus, intracranial pressure can be dynamically measured. Furthermore, use of acoustics allows the measurement to be completely non-invasive. In the preferred embodiment, phase comparison of a reflected acoustic signal to a reference signal using a constant frequency pulsed phase-locked-loop ultrasonic device allows the pulsatile components to be monitored. Calibrating the device by inducing a known change in intracranial pressure allows conversion to changes in intracranial pressure.

Implanted Blood-Pressure-Measuring Device

NASA Technical Reports Server (NTRS)

Fischell, Robert E.

1988-01-01

Arterial pressure compared with ambient bodily-fluid pressure. Implanted apparatus, capable of measuring blood pressure of patient, includes differential-pressure transducer connected to pressure sensor positioned in major artery. Electrical signal is function of differential pressure between blood-pressure sensor and reference-pressure sensor transmitted through skin of patient to recorder or indicator.

Measuring Time-Averaged Blood Pressure

NASA Technical Reports Server (NTRS)

Rothman, Neil S.

1988-01-01

Device measures time-averaged component of absolute blood pressure in artery. Includes compliant cuff around artery and external monitoring unit. Ceramic construction in monitoring unit suppresses ebb and flow of pressure-transmitting fluid in sensor chamber. Transducer measures only static component of blood pressure.

Multi-Channel Electronically Scanned Cryogenic Pressure Sensor And Method For Making Same

NASA Technical Reports Server (NTRS)

Chapman, John J. (Inventor); Hopson, Purnell, Jr. (Inventor); Holloway, Nancy M. (Inventor)

2001-01-01

A miniature, multi-channel, electronically scanned pressure measuring device uses electrostatically bonded silicon dies in a multi-element array. These dies are bonded at specific sites on a glass, pre-patterned substrate. Thermal data is multiplexed and recorded on each individual pressure measuring diaphragm. The device functions in a cryogenic environment without the need of heaters to keep the sensor at constant temperatures.

An optical manometer-on-a-chip

NASA Astrophysics Data System (ADS)

Jin, Yuhang; Crozier, Kenneth B.

2011-10-01

The rapid development of microfluidic devices in recent years has led to a huge number of applications in chemistry, biology and interdisciplinary areas. This is because they act as miniaturized platforms in which sorting, mixing, reaction and measurement can be achieved in a precise and rapid manner. Being able to both understand and measure the pressure of fluids inside these devices is very important, especially in the cases where multiphase flows are involved. For example, certain advanced micromixing technologies demand accurate evaluations of bubble-induced extra pressure, since the pressure contribution from one bubble is likely to impact the velocity and residence time of others, affecting the mixing efficiency and quality in a complicated manner. Similarly, in some microfluidics-based biochemical analysis, extra pressure brought about by droplets is a critical factor in the design of on-chip pumping, as high throughput experiments involving continuous supply of large numbers of droplets often require a considerable enhancement in the pumping pressure necessary to maintain the droplet flow3. Last, state-of-the-art microfluidic logic devices rely heavily on the pressure distribution inside the channels, which automatically controls the paths of each droplet in the microfluidic network and as a result determines the "on" and "off" of each switch. A few techniques to measure pressure change or pressure drop in microfluidic channels have been developed. Examples include connecting the device to commercially available pressure sensors and comparing pressures of different areas by analyzing the position of fluid-fluid interface. However, all of those methods have intrinsic drawbacks in one or more aspects that considerably limit their applications. A significant one is that they are primarily aiming at measuring or comparing pressures over relatively long channels (~10 mm), and are hence only designed to work in the highpressure range, i.e. to detect a pressure change on the order of tens or hundreds of Pascals. Moreover, the long channels make it rather challenging to look into the detailed dynamics of pressure variations caused by inhomogeneous emulsions, since such a long section invariably contains multiple elements, for instance droplets, of the emulsion flow, and the measurements average out the behavior of one single element. Consequently, to further reveal the characteristics of flows in microfluidics, it is highly desirable for a pressure measurement device to work in the low-pressure range, and to resolve pressure changes "locally", i.e. within small spatial regions.

Noninvasive Hemodynamic Measurements During Neurosurgical Procedures in Sitting Position.

PubMed

Schramm, Patrick; Tzanova, Irene; Gööck, Tilman; Hagen, Frank; Schmidtmann, Irene; Engelhard, Kristin; Pestel, Gunther

2017-07-01

Neurosurgical procedures in sitting position need advanced cardiovascular monitoring. Transesophageal echocardiography (TEE) to measure cardiac output (CO)/cardiac index (CI) and stroke volume (SV), and invasive arterial blood pressure measurements for systolic (ABPsys), diastolic (ABPdiast) and mean arterial pressure (MAP) are established monitoring technologies for these kind of procedures. A noninvasive device for continuous monitoring of blood pressure and CO based on a modified Penaz technique (volume-clamp method) was introduced recently. In the present study the noninvasive blood pressure measurements were compared with invasive arterial blood pressure monitoring, and the noninvasive CO monitoring to TEE measurements. Measurements of blood pressure and CO were performed in 35 patients before/after giving a fluid bolus and a change from supine to sitting position, start of surgery, and repositioning from sitting to supine at the end of surgery. Data pairs from the noninvasive device (Nexfin HD) versus arterial line measurements (ABPsys, ABPdiast, MAP) and versus TEE (CO, CI, SV) were compared using Bland-Altman analysis and percentage error. All parameters compared (CO, CI, SV, ABPsys, ABPdiast, MAP) showed a large bias and wide limits of agreement. Percentage error was above 30% for all parameters except ABPsys. The noninvasive device based on a modified Penaz technique cannot replace arterial blood pressure monitoring or TEE in anesthetized patients undergoing neurosurgery in sitting position.

Recommendations for blood pressure measurement in humans and experimental animals: Part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research.

PubMed

Pickering, Thomas G; Hall, John E; Appel, Lawrence J; Falkner, Bonita E; Graves, John; Hill, Martha N; Jones, Daniel W; Kurtz, Theodore; Sheps, Sheldon G; Roccella, Edward J

2005-01-01

Accurate measurement of blood pressure is essential to classify individuals, to ascertain blood pressure-related risk, and to guide management. The auscultatory technique with a trained observer and mercury sphygmomanometer continues to be the method of choice for measurement in the office, using the first and fifth phases of the Korotkoff sounds, including in pregnant women. The use of mercury is declining, and alternatives are needed. Aneroid devices are suitable, but they require frequent calibration. Hybrid devices that use electronic transducers instead of mercury have promise. The oscillometric method can be used for office measurement, but only devices independently validated according to standard protocols should be used, and individual calibration is recommended. They have the advantage of being able to take multiple measurements. Proper training of observers, positioning of the patient, and selection of cuff size are all essential. It is increasingly recognized that office measurements correlate poorly with blood pressure measured in other settings, and that they can be supplemented by self-measured readings taken with validated devices at home. There is increasing evidence that home readings predict cardiovascular events and are particularly useful for monitoring the effects of treatment. Twenty-four-hour ambulatory monitoring gives a better prediction of risk than office measurements and is useful for diagnosing white-coat hypertension. There is increasing evidence that a failure of blood pressure to fall during the night may be associated with increased risk. In obese patients and children, the use of an appropriate cuff size is of paramount importance.

Recommendations for blood pressure measurement in humans and experimental animals: part 1: blood pressure measurement in humans: a statement for professionals from the Subcommittee of Professional and Public Education of the American Heart Association Council on High Blood Pressure Research.

PubMed

Pickering, Thomas G; Hall, John E; Appel, Lawrence J; Falkner, Bonita E; Graves, John; Hill, Martha N; Jones, Daniel W; Kurtz, Theodore; Sheps, Sheldon G; Roccella, Edward J

2005-02-08

Accurate measurement of blood pressure is essential to classify individuals, to ascertain blood pressure-related risk, and to guide management. The auscultatory technique with a trained observer and mercury sphygmomanometer continues to be the method of choice for measurement in the office, using the first and fifth phases of the Korotkoff sounds, including in pregnant women. The use of mercury is declining, and alternatives are needed. Aneroid devices are suitable, but they require frequent calibration. Hybrid devices that use electronic transducers instead of mercury have promise. The oscillometric method can be used for office measurement, but only devices independently validated according to standard protocols should be used, and individual calibration is recommended. They have the advantage of being able to take multiple measurements. Proper training of observers, positioning of the patient, and selection of cuff size are all essential. It is increasingly recognized that office measurements correlate poorly with blood pressure measured in other settings, and that they can be supplemented by self-measured readings taken with validated devices at home. There is increasing evidence that home readings predict cardiovascular events and are particularly useful for monitoring the effects of treatment. Twenty-four-hour ambulatory monitoring gives a better prediction of risk than office measurements and is useful for diagnosing white-coat hypertension. There is increasing evidence that a failure of blood pressure to fall during the night may be associated with increased risk. In obese patients and children, the use of an appropriate cuff size is of paramount importance.

Validation of the Rossmax CF175 upper-arm blood pressure monitor for home blood pressure monitoring according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Zhang, Lu; Kang, Yuan-Yuan; Zeng, Wei-Fang; Li, Yan; Wang, Ji-Guang

2015-04-01

The present study aimed to evaluate the accuracy of the Rossmax CF175 upper-arm blood pressure monitor for home blood pressure monitoring according to the International Protocol of the European Society of Hypertension revision 2010. Systolic and diastolic blood pressures were sequentially measured in 33 adult Chinese (17 women, mean age 46 years) using a mercury sphygmomanometer (two observers) and the Rossmax CF175 device (one supervisor). A total of 99 pairs of comparisons were obtained from 33 participants for judgments in two parts with three grading phases. All the blood pressure requirements were fulfilled. The Rossmax CF175 device achieved the targets in part 1 of the validation study. The number of absolute differences between the device and observers within 5, 10, and 15 mmHg was 78/99, 94/99, and 98/99, respectively, for systolic blood pressure, and 81/99, 96/99, and 97/99, respectively, for diastolic blood pressure. The device also achieved the criteria in part 2 of the validation study. Twenty-nine participants, for both of systolic and diastolic blood pressure, had at least two of the three device-observers differences within 5 mmHg (required ≥24). Only one participant for diastolic blood pressure had all three device-observers comparisons greater than 5 mmHg. The Rossmax automated oscillometric upper-arm blood pressure monitor CF175 fulfilled the requirements of the International Protocol revision 2010, and hence can be recommended for blood pressure measurement in adults.

Validation of the Andon KD-5965 upper-arm blood pressure monitor for home blood pressure monitoring according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Huang, Jinhua; Li, Zhijie; Li, Guimei; Liu, Zhaoying

2015-10-01

This study aimed to evaluate the accuracy of the Andon KD-5965 upper-arm blood pressure monitor according to the European Society of Hypertension International Protocol revision 2010. Systolic and diastolic blood pressures were sequentially measured in 33 adults, with 20 women using a mercury sphygmomanometer (two observers) and the Andon KD-5965 device (one supervisor). A total of 99 pairs of comparisons were obtained from 33 participants for judgments in two parts with three grading phases. The device achieved the targets in part 1 of the validation study. The number of absolute differences between the device and observers within 5, 10, and 15 mmHg was 70/99, 91/99, and 98/99, respectively, for systolic blood pressure and 81/99, 99/99, and 99/99, respectively, for diastolic blood pressure. The device also fulfilled the criteria in part 2 of the validation study. Twenty-five and 29 participants, for systolic and diastolic blood pressure, respectively, had at least two of the three device-observers differences within 5 mmHg (required≥24). Two and one participants for systolic and diastolic blood pressure, respectively, had all three device-observers comparisons greater than 5 mmHg. According to the validation results, with better performance for diastolic blood pressure than that for systolic blood pressure, the Andon automated oscillometric upper-arm blood pressure monitor KD-5965 fulfilled the requirements of the European Society of Hypertension International Protocol revision 2010, and hence can be recommended for blood pressure measurement in adults.

Apparatus for gas sorption measurement with integrated gas composition measurement device and gas mixing

DOEpatents

Micklash. II, Kenneth James; Dutton, Justin James; Kaye, Steven

2014-06-03

An apparatus for testing of multiple material samples includes a gas delivery control system operatively connectable to the multiple material samples and configured to provide gas to the multiple material samples. Both a gas composition measurement device and pressure measurement devices are included in the apparatus. The apparatus includes multiple selectively openable and closable valves and a series of conduits configured to selectively connect the multiple material samples individually to the gas composition device and the pressure measurement devices by operation of the valves. A mixing system is selectively connectable to the series of conduits and is operable to cause forced mixing of the gas within the series of conduits to achieve a predetermined uniformity of gas composition within the series of conduits and passages.

Wind tunnel model and method

NASA Technical Reports Server (NTRS)

Jackson, C. M., Jr.; Summerfield, D. G. (Inventor)

1974-01-01

The design and development of a wind tunnel model equipped with pressure measuring devices are discussed. The pressure measuring orifices are integrally constructed in the wind tunnel model and do not contribute to distortions of the aerodynamic surface. The construction of a typical model is described and a drawing of the device is included.

Pressure-relieving properties of a intra-operative warming device.

PubMed

Baker, E A; Leaper, D J

2003-04-01

The primary objective of this study was to determine differences in interface pressure between four mattress combinations: a standard operating table mattress, a pressure-relieving gel pad and an under-patient warming device set at 38 degrees C (Pegasus Inditherm System) and at ambient temperature. The secondary objective was to determine whether the warming device remains stable in extreme surgical positions. Interface pressures obtained with all four combinations were measured in 10 healthy volunteers using force sensing array technology. The warming device demonstrated better or equivalent pressure relief when compared with the standard gel pad. There was no significant difference in subject position 'shift' between the mattress, the gel pad and the warming device for either the Trendelenberg or reverse Trendelenberg positions. Both pressure-relieving mattresses and warming reduce intra-operative pressure damage. A mattress with both properties may further reduce pressure damage postoperatively. The warming device used in this study appears stable--subject 'slippage' was minimal in extreme positions. Research needs to be conducted among real anaesthetised patients to support these conclusions.

Thermoelectric Control Of Temperatures Of Pressure Sensors

NASA Technical Reports Server (NTRS)

Burkett, Cecil G., Jr.; West, James W.; Hutchinson, Mark A.; Lawrence, Robert M.; Crum, James R.

1995-01-01

Prototype controlled-temperature enclosure containing thermoelectric devices developed to house electronically scanned array of pressure sensors. Enclosure needed because (1) temperatures of transducers in sensors must be maintained at specified set point to ensure proper operation and calibration and (2) sensors sometimes used to measure pressure in hostile environments (wind tunnels in original application) that are hotter or colder than set point. Thus, depending on temperature of pressure-measurement environment, thermoelectric devices in enclosure used to heat or cool transducers to keep them at set point.

A novel wearable device for continuous, non-invasion blood pressure measurement.

PubMed

Xin, Qin; Wu, Jianping

2017-08-01

In this paper, we have developed a wearable cuffless device for daily blood pressure (BP) measurement. We incorporated the light based sensor and other hard wares in a small volume for BP detection. With optimized algorithm, the real-time BP reading could be achieved, the data could be presented in the screen and be transmitted by internet of things (IoT) for history data comparison and multi-terminal viewing. Thus, further analysis provides the probability for diet or sports suggestion and alarm. We have measured BP from more than 60 subjects, compare to traditional mercury blood pressure meter, no obvious error in both systolic blood pressure (SBP) and diastolic blood pressure (DBP) are detected. Such device can be used for continues non-invasion BP detection, and further data docking and health analysis could be achieved. Copyright © 2017. Published by Elsevier Ltd.

Validation of the iHealth BP5 wireless upper arm blood pressure monitor for self-measurement according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Shang, Fujun; Zhu, Yizheng; Zhu, Zhenlai; Liu, Lei; Wan, Yi

2013-10-01

The aim of this study was to validate the iHealth BP5 wireless upper arm blood pressure (BP) monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010. The ESH-IP revision 2010 for validation of BP measuring devices in adults was followed precisely. A total of 99 pairs of test device and reference BP measurements (three pairs for each of the 33 participants) were obtained in the study. The device produced 71, 89, and 97 measurements within 5, 10, and 15 mmHg for systolic blood pressure (SBP) and 73, 90, and 99 mmHg for diastolic blood pressure (DBP), respectively. The mean ± SD device-observer difference was -1.21 ± 5.87 mmHg for SBP and -1.04 ± 5.28 mmHg for DBP. The number of participants with two or three device-observer differences within 5 mmHg was 25 for SBP and 28 for DBP. In addition, three participants had no device-observer difference within 5 mmHg for SBP and none of the participants had the same for DBP. According to the validation results on the basis of the ESH-IP revision 2010, the iHealth BP5 wireless upper arm BP monitor can be recommended for self/home measurement in an adult population.

Conformable amplified lead zirconate titanate sensors with enhanced piezoelectric response for cutaneous pressure monitoring.

PubMed

Dagdeviren, Canan; Su, Yewang; Joe, Pauline; Yona, Raissa; Liu, Yuhao; Kim, Yun-Soung; Huang, YongAn; Damadoran, Anoop R; Xia, Jing; Martin, Lane W; Huang, Yonggang; Rogers, John A

2014-08-05

The ability to measure subtle changes in arterial pressure using devices mounted on the skin can be valuable for monitoring vital signs in emergency care, detecting the early onset of cardiovascular disease and continuously assessing health status. Conventional technologies are well suited for use in traditional clinical settings, but cannot be easily adapted for sustained use during daily activities. Here we introduce a conformal device that avoids these limitations. Ultrathin inorganic piezoelectric and semiconductor materials on elastomer substrates enable amplified, low hysteresis measurements of pressure on the skin, with high levels of sensitivity (~0.005 Pa) and fast response times (~0.1 ms). Experimental and theoretical studies reveal enhanced piezoelectric responses in lead zirconate titanate that follow from integration on soft supports as well as engineering behaviours of the associated devices. Calibrated measurements of pressure variations of blood flow in near-surface arteries demonstrate capabilities for measuring radial artery augmentation index and pulse pressure velocity.

Indirect Blood Pressure Measuring Device

NASA Technical Reports Server (NTRS)

Hum, L.; Cole, C. E.

1973-01-01

Design and performance of a blood pressure recording device for pediatric use are reported. A strain gage transducer with a copper-beryllium strip as force sensing element is used to monitor skin movements and to convert them into electrical signals proportional to those displacements. Experimental tests with this device in recording of force developed above the left femoral artery of a dog accurately produced a blood pressure curve.

Validation of a Piezoelectric Sensor Array-Based Device for Measurement of Carotid-Femoral Pulse Wave Velocity: The Philips Prototype.

PubMed

Xu, Shao-Kun; Hong, Xiang-Fei; Cheng, Yi-Bang; Liu, Chang-Yuan; Li, Yan; Yin, Bin; Wang, Ji-Guang

2018-03-01

Multiple piezoelectric pressure mechanotransducers topologized into an array might improve efficiency and accuracy in collecting arterial pressure waveforms for measurement of pulse wave velocity (PWV). In the present study, we validated a piezoelectric sensor array-based prototype (Philips) against the validated and clinically widely used Complior device (Alam Medical). We recruited 33 subjects with a wide distribution of PWV. For the validation, PWV was measured sequentially with the Complior device (four times) and the Philips prototype (three times). With the 99 paired PWV values, we investigated the agreement between the Philips prototype and the Complior device using Pearson correlation analysis and Bland-Altman plot. We also performed analysis on the determinants and reproducibility of PWV measured with both devices. The correlation coefficient for PWV measured with the two devices was 0.92 ( p < 0.0001). Compared with the Complior device, the Philips prototype slightly overestimated PWV by 0.24 (± 2 standard deviations, ± 1.91) m/s, especially when PWV was high. The correlation coefficient between the difference and the average of the Philips and Complior measurements was 0.21 ( p = 0.035). Nonetheless, they had similar determinants. Age, mean arterial pressure, and sex altogether explained 81.6 and 83.9% of the variance of PWV values measured with the Philips prototype and Complior device, respectively. When the two extremes of the three PWV values measured with the Philips prototype and the Complior device were investigated, the coefficients of variation were 8.26 and 3.26%, respectively. Compared with the Complior device, the Philips prototype had similar accuracy, determinants, and reproducibility in measuring PWV.

Smartphone-based Continuous Blood Pressure Measurement Using Pulse Transit Time.

PubMed

Gholamhosseini, Hamid; Meintjes, Andries; Baig, Mirza; Linden, Maria

2016-01-01

The increasing availability of low cost and easy to use personalized medical monitoring devices has opened the door for new and innovative methods of health monitoring to emerge. Cuff-less and continuous methods of measuring blood pressure are particularly attractive as blood pressure is one of the most important measurements of long term cardiovascular health. Current methods of noninvasive blood pressure measurement are based on inflation and deflation of a cuff with some effects on arteries where blood pressure is being measured. This inflation can also cause patient discomfort and alter the measurement results. In this work, a mobile application was developed to collate the PhotoPlethysmoGramm (PPG) waveform provided by a pulse oximeter and the electrocardiogram (ECG) for calculating the pulse transit time. This information is then indirectly related to the user's systolic blood pressure. The developed application successfully connects to the PPG and ECG monitoring devices using Bluetooth wireless connection and stores the data onto an online server. The pulse transit time is estimated in real time and the user's systolic blood pressure can be estimated after the system has been calibrated. The synchronization between the two devices was found to pose a challenge to this method of continuous blood pressure monitoring. However, the implemented continuous blood pressure monitoring system effectively serves as a proof of concept. This combined with the massive benefits that an accurate and robust continuous blood pressure monitoring system would provide indicates that it is certainly worthwhile to further develop this system.

Validation protocols for blood pressure-measuring devices: status quo and development needs.

PubMed

Beime, Beate; Deutsch, Cornelia; Gomez, Timothy; Zwingers, Thomas; Mengden, Thomas; Bramlage, Peter

2016-02-01

Hypertension is a major risk factor for cardiovascular morbidity and mortality. Therefore, blood pressure self-measuring devices have emerged as valuable tools in patient care and the accuracy of these instruments is of fundamental importance. For this reason, several validation procedures for assessing the efficacy of blood pressure monitoring devices have been developed, including protocols by the Association for the Advancement of Medical Instrumentation, the British Hypertension Society, the German Hypertension League (Prüfsiegelprotokoll), and the International Protocol of the Working Group on Blood Pressure Monitoring of the European Society of Hypertension. In the past, most of the protocols have been reviewed and modified because of experiences gained during the validation studies carried out. However, each shows distinct differences, that is number and characteristics of patients required, blood pressure ranges, and the length of the validation procedure, which may result in unique advantages and/or limitations associated with their use. The continued standardization and evolution of these guidelines is essential to ensure the efficacy of blood pressure-measuring devices marketed for clinical and home use. Here, we aimed to compare four currently used validation protocols and to initiate a discussion on potential future improvements.

Evaluation of the Mobil-O-Graph new generation ABPM device using the ESH criteria.

PubMed

Franssen, Pascal M L; Imholz, Ben P M

2010-08-01

We report on the validation of the new generation Mobil-O-Graph 24/48 h ambulatory blood pressure monitor according to the criteria of the European Society of Hypertension. In 15 individuals participating in phase I for systolic pressure, all 45 measures differed less than 15 mmHg, 43 and 33 out of 45 differed less than 10 and 5 mmHg. As for diastolic pressures even better scores were reached when the device passed the EHS score. In phase II, data were collected in an additional 18 individuals leaving a total of 33 individuals and 99 measures. The phase counts the achieved percentages of two or three measures per individual within 15, 10 and 5 mmHg limits. Systolic pressures exceeded the required 95, 80 and 65% for 15, 10 and 5 mmHg differences with values of 98, 94 and 71%, respectively. As again for diastolic pressure the values were even better, the device passed phase II also. Thus, all phases of the European Society of Hypertension procedure were passed and the results of this study can recommend the use of the Mobil-O-Graph new generation ambulatory blood pressure monitor device in clinical practice.

The measurement of tissue interface pressures and changes in jugular venous parameters associated with cervical immobilisation devices: a systematic review

PubMed Central

2013-01-01

Cervical immobilisation is commonly applied following trauma, particularly blunt head injury, but current methods of immobilisation are associated with significant complications. Semi-rigid disposable cervical collars are known to cause pressure ulcers, and impede effective airway management. These collars may also exacerbate a head injury by increasing intracranial pressure as a result of external compression of the jugular veins. There is a clear imperative to find ways of effectively immobilising the cervical spine whilst minimising complications, and any assessment of existing or new devices should include a standardized approach to the measurement of tissue interface pressures and their effect on jugular venous drainage from the brain. This systematic review summarises the research methods and technologies that have been used to measure tissue interface pressure and assess the jugular vein in the context of cervical immobilisation devices. 27 papers were included and assessed for quality. Laboratory investigations and biomechanical studies have gradually given way to methods that more accurately reflect clinical care. There are numerous accounts of skin ulceration associated with cervical collars, but no standardised approach to measuring tissue interface pressure. It is therefore difficult to compare studies and devices, but a pressure of less than 30 mmHg appears desirable. Cervical collars have been shown to have a compressive effect on the jugular veins, but it is not yet certain that this is the cause of the increased intracranial pressure observed in association with cervical collar use. This is the first review of its type. It will help guide further research in this area of trauma care, and the development and testing of new cervical immobilisation devices. PMID:24299024

Device for accurately measuring mass flow of gases

DOEpatents

Hylton, J.O.; Remenyik, C.J.

1994-08-09

A device for measuring mass flow of gases which utilizes a substantially buoyant pressure vessel suspended within a fluid/liquid in an enclosure is disclosed. The pressure vessel is connected to a weighing device for continuously determining weight change of the vessel as a function of the amount of gas within the pressure vessel. In the preferred embodiment, this pressure vessel is formed from inner and outer right circular cylindrical hulls, with a volume between the hulls being vented to the atmosphere external the enclosure. The fluid/liquid, normally in the form of water typically with an added detergent, is contained within an enclosure with the fluid/liquid being at a level such that the pressure vessel is suspended beneath this level but above a bottom of the enclosure. The buoyant pressure vessel can be interconnected with selected valves to an auxiliary pressure vessel so that initial flow can be established to or from the auxiliary pressure vessel prior to flow to or from the buoyant pressure vessel. 5 figs.

Device for accurately measuring mass flow of gases

DOEpatents

Hylton, James O.; Remenyik, Carl J.

1994-01-01

A device for measuring mass flow of gases which utilizes a substantially buoyant pressure vessel suspended within a fluid/liquid in an enclosure. The pressure vessel is connected to a weighing device for continuously determining weight change of the vessel as a function of the amount of gas within the pressure vessel. In the preferred embodiment, this pressure vessel is formed from inner and outer right circular cylindrical hulls, with a volume between the hulls being vented to the atmosphere external the enclosure. The fluid/liquid, normally in the form of water typically with an added detergent, is contained within an enclosure with the fluid/liquid being at a level such that the pressure vessel is suspended beneath this level but above a bottom of the enclosure. The buoyant pressure vessel can be interconnected with selected valves to an auxiliary pressure vessel so that initial flow can be established to or from the auxiliary pressure vessel prior to flow to or from the buoyant pressure vessel.

Validation of A&D TM-2430 upper-arm blood pressure monitor for ambulatory blood pressure monitoring in children and adolescents, according to the British Hypertension Society protocol.

PubMed

Yip, Gabriel Wai-Kwok; So, Hung-Kwan; Li, Albert Martin; Tomlinson, Brian; Wong, Sik-Nin; Sung, Rita Yn-Tz

2012-04-01

The A&D TM-2430 ambulatory blood pressure (BP) monitor has been validated in adults but not in a young population. We sought to validate the device monitoring in children and adolescents, according to the British Hypertension Society (BHS) protocol. The A&D TM-2430 is an automated oscillometric upper-arm device for ambulatory BP monitoring. Nine consecutive measurements were taken in 61 children (mean age, 9.8 years; range, 5-15 years) according to the BHS criteria. Overseen by an independent supervisor, measurements were recorded by two observers blinded from each other's readings and from the device readings. The mean difference ± SD between the observers and device measurements was 0.73 ± 1.64 mmHg for systolic blood pressure (SBP) and -1.23 ± 1.65 mmHg for diastolic blood pressure (DBP), respectively, with an interobserver difference of 4 mmHg. The cumulative percentages of differences within 5, 10, and 15 mmHg were 89, 95, and 98% for SBP and 67, 88, and 98% for DBP. The device achieved a grade A rating for SBP and a B grade for DBP. The A&D TM-2430 upper-arm BP monitor has fulfilled the required BHS standards and can be recommended for measuring ambulatory BP in children and adolescent populations.

Validation of the Andon KD595 for clinical use and self-measurement according to the European Society of Hypertension International Protocol.

PubMed

Wu, Ning; Zhang, Xuezhong; Wang, Wen; Zhang, Hongye

2016-04-01

This study aimed to evaluate the accuracy of the automated oscillometric upper arm blood pressure monitor Andon KD595 for home blood pressure monitoring according to the European Society of Hypertension International Protocol revision 2010. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were sequentially measured in 33 participants using the standard mercury sphygmomanometer and the Andon KD595 device. Ninety-nine pairs of comparisons were obtained from 33 participants for analysis. The KD595 device achieved the targets in part 1 of the validation study. The number of absolute differences between the device and the observers within a range of 5, 10, and 15 mmHg was 72/99, 93/99, and 96/99, respectively, for SBP and 72/99, 96/99, and 99/99, respectively, for DBP. The device also achieved the targets in part 2 of the validation study. A total of 28 and 25 participants had at least two of the three device-observer differences within 5 mmHg (required≥24) for SBP and DBP, respectively. The number of participants without device-observer difference within 5 mmHg was two for SBP and two for DBP (required≤3). The Andon upper arm blood pressure monitor KD595 has passed the International Protocol requirements and it can be recommended for clinical use and self-measurement in adults.

A real-time plantar pressure feedback device for foot unloading.

PubMed

Femery, Virginie G; Moretto, Pierre G; Hespel, Jean-Michel G; Thévenon, André; Lensel, Ghislaine

2004-10-01

To develop and test a plantar pressure control device that provides both visual and auditory feedback and is suitable for correcting plantar pressure distribution patterns in persons susceptible to neuropathic foot ulceration. Pilot test. Sports medicine laboratory in a university in France. One healthy man in his mid thirties. Not applicable. Main outcome measures A device was developed based on real-time feedback, incorporating an acoustic alarm and visual signals, adjusted to a specific pressure load. Plantar pressure measured during walking, at 6 sensor locations over 27 steps under 2 different conditions: (1) natural and (2) unloaded in response to device feedback. The subject was able to modify his gait in response to the auditory and visual signals. He did not compensate for the decrease of peak pressure under the first metarsal by increasing the duration of the load shift under this area. Gait pattern modification centered on a mediolateral load shift. The auditory signal provided a warning system alerting the user to potentially harmful plantar pressures. The visual signal warned of the degree of pressure. People who have lost nociceptive perception, as in cases of diabetic neuropathy, may be able to change their walking pattern in response to the feedback provided by this device. The visual may have diagnostic value in determining plantar pressures in such patients. This pilot test indicates that further studies are warranted.

Validation of the AVITA BPM63S upper arm blood pressure monitor for home blood pressure monitoring according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Kang, Yuan-Yuan; Zeng, Wei-Fang; Liu, Ming; Li, Yan; Wang, Ji-Guang

2014-02-01

The present study aimed to evaluate the accuracy of the AVITA BPM63S upper arm blood pressure monitor for home blood pressure monitoring according to the International Protocol of the European Society of Hypertension revision 2010. Systolic and diastolic blood pressures were sequentially measured in 33 adult Chinese (14 women, mean age of 47 years) using a mercury sphygmomanometer (two observers) and the AVITA BPM63S device (one supervisor). Ninety-nine pairs of comparisons were obtained from 33 participants for judgments in two parts with three grading phases. All the blood pressure requirements were fulfilled. The AVITA BPM63S device achieved the targets in part 1 of the validation study. The number of absolute differences between device and observers within 5, 10, and 15 mmHg was 68/99, 89/99, and 96/99, respectively, for systolic blood pressure, and 75/99, 95/99, and 97/99, respectively, for diastolic blood pressure. The device also achieved the criteria in part 2 of the validation study. Twenty-four and 25 participants for systolic and diastolic blood pressure, respectively, had at least two of the three device-observers differences within 5 mmHg (required ≥24). One and two participants for systolic and diastolic blood pressure, respectively, had all three device-observers differences greater than 5 mmHg. The AVITA BPM63S automated oscillometric upper arm blood pressure monitor has passed the requirements of the International Protocol revision 2010, and hence can be recommended for blood pressure measurement at home in adults.

Quality Control Method for a Micro-Nano-Channel Microfabricated Device

NASA Technical Reports Server (NTRS)

Grattoni, Alessandro; Ferrari, Mauro; Li, Xuewu

2012-01-01

A variety of silicon-fabricated devices is used in medical applications such as drug and cell delivery, and DNA and protein separation and analysis. When a fluidic device inlet is connected to a compressed gas reservoir, and the outlet is at a lower pressure, a gas flow occurs through the membrane toward the outside. The method relies on the measurement of the gas pressure over the elapsed time inside the upstream and downstream environments. By knowing the volume of the upstream reservoir, the gas flow rate through the membrane over the pressure drop can be calculated. This quality control method consists of measuring the gas flow through a device and comparing the results with a standard curve, which can be obtained by testing standard devices. Standard devices can be selected through a variety of techniques, both destructive and nondestructive, such as SEM, AFM, and standard particle filtration.

Brain Pressure Monitoring

NASA Technical Reports Server (NTRS)

1977-01-01

A transducer originally used to measure air pressure in aircraft wind tunnel tests is the basis for a development important in diagnosis and treatment of certain types of brain damage. A totally implantable device, tbe intracranial pressure monitor measures and reports brain pressure by telemetry.

Beta ray flux measuring device

DOEpatents

Impink, Jr., Albert J.; Goldstein, Norman P.

1990-01-01

A beta ray flux measuring device in an activated member in-core instrumentation system for pressurized water reactors. The device includes collector rings positioned about an axis in the reactor's pressure boundary. Activated members such as hydroballs are positioned within respective ones of the collector rings. A response characteristic such as the current from or charge on a collector ring indicates the beta ray flux from the corresponding hydroball and is therefore a measure of the relative nuclear power level in the region of the reactor core corresponding to the specific exposed hydroball within the collector ring.

Validation of the Tensoval Duo Control II blood pressure monitor for clinic use and self-measurement according to the British Hypertension Society protocol and the European Society of Hypertension International Protocol Revision 2010.

PubMed

de Greeff, Annemarie; Shennan, Andrew H

2013-06-01

The Tensoval Duo Control II is an automated upper arm device that uses a combination of oscillometric and auscultatory technology to determine blood pressure noninvasively. The accuracy of this device was assessed according to the British Hypertension Society (BHS) protocol and the European Society of Hypertension International Protocol revision 2010 (ESH-IP2) in an adult population. Ethical approval was obtained. Eighty-five and 33 adult individuals, respectively, were recruited to fulfil the requirements of each protocol. Trained observers took nine sequential same-arm measurements alternating between a mercury sphygmomanometer and the device. The device had to achieve at least a B grade for both systolic and diastolic pressures to pass the BHS protocol and had to fulfil the criteria of all three phases of the ESH-IP2 protocol to receive recommendation. The device achieved an A/A grading for the BHS protocol and passed all three phases of the ESH-IP2 protocol. The mean difference±SD for the BHS/ESH protocols, respectively, was -1.8±6.5/-0.7±5.7 mmHg for systolic pressure and 1.9±5.1/2.4±4.5 mmHg for diastolic pressure. The device maintained its A/A grading throughout the low-pressure, medium-pressure and high-pressure ranges. The Tensoval Duo Control II device is recommended for clinical and home use according to both the BHS and the ESH-IP2 standard.

Validation of the Medisana MTP Plus upper arm blood pressure monitor, for self-measurement, according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Erdem, Emre; Aydogdu, Türkan; Akpolat, Tekin

2011-02-01

Standard validation protocols are objective guides for healthcare providers, physicians, and patients. The purpose of this study was to test validation of the Medisana MTP Plus upper arm blood pressure (BP) measuring monitor for self-measurement according to the European Society of Hypertension International Protocol (ESH-IP2) in adults. The Medisana MTP Plus monitor is an automated and oscillometric upper arm device for home BP monitoring. Nine consecutive measurements were made according to the ESH-IP2. Overseen by an independent supervisor, measurements were recorded by two observers blinded from both each other's readings and from the device readings. The Medisana MTP Plus device fulfills the validation criteria of the ESH-IP2 for the general population. The mean (standard deviation) of the difference between the observers and the device measurements was 0.6 mmHg (5.1 mmHg) for systolic and 2.7 mmHg (3.4 mmHg) for diastolic pressures, respectively. As the Medisana MTP Plus device has achieved the required standards, it is recommended for home BP monitoring in an adult population.

21 CFR 886.1930 - Tonometer and accessories.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1930 Tonometer and accessories. (a) Identification. A tonometer and accessories is a manual device intended to measure intraocular pressure by applying a known force on the globe of the eye and measuring the amount of indentation produced (Schiotz...

Self-correcting electronically scanned pressure sensor

NASA Technical Reports Server (NTRS)

Gross, C. (Inventor)

1983-01-01

A multiple channel high data rate pressure sensing device is disclosed for use in wind tunnels, spacecraft, airborne, process control, automotive, etc., pressure measurements. Data rates in excess of 100,000 measurements per second are offered with inaccuracies from temperature shifts less than 0.25% (nominal) of full scale over a temperature span of 55 C. The device consists of thirty-two solid state sensors, signal multiplexing electronics to electronically address each sensor, and digital electronic circuitry to automatically correct the inherent thermal shift errors of the pressure sensors and their associated electronics.

Measurement correction method for force sensor used in dynamic pressure calibration based on artificial neural network optimized by genetic algorithm

NASA Astrophysics Data System (ADS)

Gu, Tingwei; Kong, Deren; Shang, Fei; Chen, Jing

2017-12-01

We present an optimization algorithm to obtain low-uncertainty dynamic pressure measurements from a force-transducer-based device. In this paper, the advantages and disadvantages of the methods that are commonly used to measure the propellant powder gas pressure, the applicable scope of dynamic pressure calibration devices, and the shortcomings of the traditional comparison calibration method based on the drop-weight device are firstly analysed in detail. Then, a dynamic calibration method for measuring pressure using a force sensor based on a drop-weight device is introduced. This method can effectively save time when many pressure sensors are calibrated simultaneously and extend the life of expensive reference sensors. However, the force sensor is installed between the drop-weight and the hammerhead by transition pieces through the connection mode of bolt fastening, which causes adverse effects such as additional pretightening and inertia forces. To solve these effects, the influence mechanisms of the pretightening force, the inertia force and other influence factors on the force measurement are theoretically analysed. Then a measurement correction method for the force measurement is proposed based on an artificial neural network optimized by a genetic algorithm. The training and testing data sets are obtained from calibration tests, and the selection criteria for the key parameters of the correction model is discussed. The evaluation results for the test data show that the correction model can effectively improve the force measurement accuracy of the force sensor. Compared with the traditional high-accuracy comparison calibration method, the percentage difference of the impact-force-based measurement is less than 0.6% and the relative uncertainty of the corrected force value is 1.95%, which can meet the requirements of engineering applications.

Systems and methods for detection of blowout precursors in combustors

DOEpatents

Lieuwen, Tim C.; Nair, Suraj

2006-08-15

The present invention comprises systems and methods for detecting flame blowout precursors in combustors. The blowout precursor detection system comprises a combustor, a pressure measuring device, and blowout precursor detection unit. A combustion controller may also be used to control combustor parameters. The methods of the present invention comprise receiving pressure data measured by an acoustic pressure measuring device, performing one or a combination of spectral analysis, statistical analysis, and wavelet analysis on received pressure data, and determining the existence of a blowout precursor based on such analyses. The spectral analysis, statistical analysis, and wavelet analysis further comprise their respective sub-methods to determine the existence of blowout precursors.

Methods of measuring water levels in deep wells

USGS Publications Warehouse

Garber, M.S.; Koopman, F. C.

1968-01-01

Accurate measurement of water levels deeper than 1,000 feet in wells requires specialized equipment. Corrections for stretch and thermal expansion of measuring tapes must be considered, and other measuring devices must be calibrated periodically. Bore-hole deviation corrections also must be made. Devices for recording fluctuation of fluid level usually require mechanical modification for use at these depths. A multichannel recording device utilizing pressure transducers has been constructed. This device was originally designed to record aquifer response to nearby underground nuclear explosions but can also be used for recording data from multi-well pumping tests. Bottom-hole recording devices designed for oil-field use have been utilized in a limited manner. These devices were generally found to lack the precision required, in ground-water investigations at the Nevada Test Site but may be applicable in other areas. A newly developed bottom-hole recording pressure gauge of improved accuracy has been used with satisfactory results.

Fluid injection device for high-pressure systems

NASA Technical Reports Server (NTRS)

Copeland, E. J.; Ward, J. B.

1970-01-01

Screw activated device, consisting of a compressor, shielded replaceable ampules, a multiple-element rubber gland, and a specially constructed fluid line fitting, injects measured amounts of fluids into a pressurized system. It is sturdy and easily manipulated.

High Precision Pressure Measurement with a Funnel

ERIC Educational Resources Information Center

Lopez-Arias, T.; Gratton, L. M.; Oss, S.

2008-01-01

A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is…

Effects of a continuous lateral turning device on pressure relief.

PubMed

Do, Nam Ho; Kim, Deog Young; Kim, Jung-Hoon; Choi, Jong Hyun; Joo, So Young; Kang, Na Kyung; Baek, Yoon Su

2016-01-01

[Purpose] The purpose of this study was to examine the pressure-relieving effects of a continuous lateral turning device on common pressure ulcer sites. [Subjects] Twenty-four healthy adults participated. [Methods] The design of our continuous lateral turning device was motivated by the need for an adequate pressure-relieving device for immobile and/or elderly people. The procedure of manual repositioning is embodied in our continuous lateral turning device. The interface pressure and time were measured, and comfort grade was evaluated during sessions of continuous lateral turning at 0°, 15°, 30°, and 45°. We quantified the pressure-relieving effect using peak pressure, mean pressure, and pressure time integration. [Results] Participants demonstrated pressure time integration values below the pressure-time threshold at 15°, 30°, and 45° at all the common pressure ulcer sites. Moreover, the most effective angles for pressure relief at the common pressure ulcer sites were 30° at the occiput, 15° at the left scapula, 45° at the right scapula, 45° at the sacrum, 15° at the right heel, and 30° at the left heel. However, angles greater than 30° induced discomfort. [Conclusion] Continuous lateral turning with our specially designed device effectively relieved the pressure of targeted sites. Moreover, the suggested angles of continuous lateral turning can be used to relieve pressure at targeted sites.

Embedded programmable blood pressure monitoring system

NASA Astrophysics Data System (ADS)

Hasan, Md. Mahmud-Ul; Islam, Md. Kafiul; Shawon, Mehedi Azad; Nowrin, Tasnuva Faruk

2010-02-01

A more efficient newer algorithm of detecting systolic and diastolic pressure of human body along with a complete package of an effective user-friendly embedded programmable blood pressure monitoring system has been proposed in this paper to reduce the overall workload of medical personals as well as to monitor patient's condition more conveniently and accurately. Available devices for measuring blood pressure have some problems and limitations in case of both analog and digital devices. The sphygmomanometer, being analog device, is still being used widely because of its reliability and accuracy over digital ones. But it requires a skilled person to measure the blood pressure and obviously not being automated as well as time consuming. Our proposed system being a microcontroller based embedded system has the advantages of the available digital blood pressure machines along with a much improved form and has higher accuracy at the same time. This system can also be interfaced with computer through serial port/USB to publish the measured blood pressure data on the LAN or internet. The device can be programmed to determine the patient's blood pressure after each certain interval of time in a graphical form. To sense the pressure of human body, a pressure to voltage transducer is used along with a cuff in our system. During the blood pressure measurement cycle, the output voltage of the transducer is taken by the built-in ADC of microcontroller after an amplifier stage. The recorded data are then processed and analyzed using the effective software routine to determine the blood pressure of the person under test. Our proposed system is thus expected to certainly enhance the existing blood pressure monitoring system by providing accuracy, time efficiency, user-friendliness and at last but not the least the 'better way of monitoring patient's blood pressure under critical care' all together at the same time.

Compensating for pneumatic distortion in pressure sensing devices

NASA Technical Reports Server (NTRS)

Whitmore, Stephen A.; Leondes, Cornelius T.

1990-01-01

A technique of compensating for pneumatic distortion in pressure sensing devices was developed and verified. This compensation allows conventional pressure sensing technology to obtain improved unsteady pressure measurements. Pressure distortion caused by frictional attenuation and pneumatic resonance within the sensing system makes obtaining unsteady pressure measurements by conventional sensors difficult. Most distortion occurs within the pneumatic tubing which transmits pressure impulses from the aircraft's surface to the measurement transducer. To avoid pneumatic distortion, experiment designers mount the pressure sensor at the surface of the aircraft, (called in-situ mounting). In-situ transducers cannot always fit in the available space and sometimes pneumatic tubing must be run from the aircraft's surface to the pressure transducer. A technique to measure unsteady pressure data using conventional pressure sensing technology was developed. A pneumatic distortion model is reduced to a low-order, state-variable model retaining most of the dynamic characteristics of the full model. The reduced-order model is coupled with results from minimum variance estimation theory to develop an algorithm to compensate for the effects of pneumatic distortion. Both postflight and real-time algorithms are developed and evaluated using simulated and flight data.

Validation of the Grandway MD2301 digital automatic blood pressure monitor according to the European Society of Hypertension International Protocol.

PubMed

Chen, Wan; Zeng, Zhao-Lin; Bing, Sen; Li, Lin-Yi; Wang, Rui; Wan, Yi

2016-08-01

The aim of the present study was to validate the Grandway MD2301 digital automatic blood pressure monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010. The ESH-IP revision 2010 for the validation of blood pressure-measuring devices in adults was followed precisely. Systolic and diastolic blood pressure (SBP and DBP, respectively) were measured sequentially in 33 adult patients and compared with a standard mercury sphygmomanometer (two observers). A total of 99 comparison pairs were obtained. The device produced 78, 95 and 99 measurements within 5, 10, and 15 mmHg for SBP and 83, 96, and 99 for DBP, respectively. The average device-observer difference was -1.81±4.22 mmHg for SBP and -0.15±3.93 mmHg for DBP. All of the data were within the standards requirements to pass the testing. The Grandway MD2301 digital automatic blood pressure monitor meets the standards of the ESH-IP revision 2010 and can be recommended for self/home measurement in the general population.

SENSITIVE PRESSURE GAUGE

DOEpatents

Ball, W.P.

1961-01-01

An electron multiplier device is described. It has a plurality of dynodes between an anode and cathode arranged to measure pressure, temperature, or other environmental physical conditions that proportionately iinfuences the quantity of gas molecules between the dynodes. The output current of the device is influenced by the reduction in electron multiplication at the dynodes due to energy reducing collisions of the electrons with the gas molecules between the dynodes. More particularly, the current is inversely proportional to the quantity of gas molecules, viz., the gas pressure. The device is, hence, extremely sensitive to low pressures.

The Timer-Logger-Communicator for Continuous, Mobile Measurement of Wheelchair Pressure Reliefs

PubMed Central

Grip, Jeffrey C.; Merbitz, Charles T.

1985-01-01

A recently developed device which provides continuous, direct monitoring of the pressure-relief performance of persons confined to wheelchairs is reported. A custom portable computer records the data, which is transferred for analysis to an Apple IIe. The mobile computer can also signal the patient to relieve pressure based on preset criteria and the patient's performance. Teaching lift-offs to prevent ischial pressure sores is the object. Data collected with the device are used clinically and for research. Examples of such data are presented. The benefits of the device are reviewed.

Comparison of the Complior Analyse device with Sphygmocor and Complior SP for pulse wave velocity and central pressure assessment.

PubMed

Stea, Francesco; Bozec, Erwan; Millasseau, Sandrine; Khettab, Hakim; Boutouyrie, Pierre; Laurent, Stéphane

2014-04-01

The Complior device (Alam Medical, France) was used in epidemiological studies which established pulse wave velocity (PWV) as a cardiovascular risk marker. Central pressure is related, but complementary to PWV and also associated to cardiovascular outcomes. The new Complior Analyse measures both PWV and central blood pressure during the same acquisition. The aim of this study was to compare PWV values from Complior Analyse with the previous Complior SP (PWVcs) and with Sphygmocor (PWVscr; AtCor, Australia), and to compare central systolic pressure from Complior Analyse and Sphygmocor. Peripheral and central pressures and PWV were measured with the three devices in 112 patients. PWV measurements from Complior Analyse were analysed using two foot-detection algorithms (PWVca_it and PWVca_cs). Both radial (ao-SBPscr) and carotid (car-SBPscr) approaches from Sphygmocor were compared to carotid Complior Analyse measurements (car-SBPca). The same distance and same calibrating pressures were used for all devices. PWVca_it was strongly correlated to PWVscr (R(2) = 0.93, P < 0.001) with a difference of 0.0 ± 0.7  m/s. PWVca_cs was also correlated to PWVcs (R(2) = 0.90, P < 0.001) with a difference of 0.1 ± 0.7  m/s. Central systolic pressures were strongly correlated. The difference between car-SBPca and ao-SBPscr was 3.1 ± 4.2  mmHg (P < 0.001), statistically equivalent to the difference between car-SBPscr and ao-SBPscr (3.9 ± 5.8  mmHg, P < 0.001), whilst the difference between car-SBPca and car-SBPscr was negligible (-0.7 ± 5.6  mmHg, P = NS). The new Complior Analyse device provides equivalent results for PWV and central pressure values to the Sphygmocor and Complior SP. It reaches Association for the Advancement of Medical Instrumentation standard for central blood pressure and grades as excellent for PWV on the Artery Society criteria. It can be interchanged with existing devices.

Pressure and Humidity Measurements at the MSL Landing Site Supported by Modeling of the Atmospheric Conditions

NASA Astrophysics Data System (ADS)

Harri, A.; Savijarvi, H. I.; Schmidt, W.; Genzer, M.; Paton, M.; Kauhanen, J.; Atlaskin, E.; Polkko, J.; Kahanpaa, H.; Kemppinen, O.; Haukka, H.

2012-12-01

The Mars Science Laboratory (MSL) called Curiosity Rover landed safely on the Martian surface at the Gale crater on 6th August 2012. Among the MSL scientific objectives are investigations of the Martian environment that will be addressed by the Rover Environmental Monitoring Station (REMS) instrument. It will investigate habitability conditions at the Martian surface by performing a versatile set of environmental measurements including accurate observations of pressure and humidity of the Martian atmosphere. This paper describes the instrumental implementation of the MSL pressure and humidity measurement devices and briefly analyzes the atmospheric conditions at the Gale crater by modeling efforts using an atmospheric modeling tools. MSL humidity and pressure devices are based on proprietary technology of Vaisala, Inc. Humidity observations make use of Vaisala Humicap® relative humidity sensor heads and Vaisala Barocap® sensor heads are used for pressure observations. Vaisala Thermocap® temperature sensors heads are mounted in a close proximity of Humicap® and Barocap® sensor heads to enable accurate temperature measurements needed for interpretation of Humicap® and Barocap® readings. The sensor heads are capacitive. The pressure and humidity devices are lightweight and are based on a low-power transducer controlled by a dedicated ASIC. The transducer is designed to measure small capacitances in order of a few pF with resolution in order of 0.1fF (femtoFarad). The transducer design has a good spaceflight heritage, as it has been used in several previous missions, for example Mars mission Phoenix as well as the Cassini Huygens mission. The humidity device has overall dimensions of 40 x 25 x 55 mm. It weighs18 g, and consumes 15 mW of power. It includes 3 Humicap® sensor heads and 1 Thermocap®. The transducer electronics and the sensor heads are placed on a single multi-layer PCB protected by a metallic Faraday cage. The Humidity device has measurement range of 0 - 100%RH in temperature range of -70°C - +25°C. Its survival temperature is as low as -135°C. The pressure device has overall dimensions of 62 x 55 x 17 mm. It weighs 35 g, and consumes 15 mW of power. The sensor makes use of two transducers placed on a single multi-layer PCB and protected by box-like FR4 Faraday cages. The transducers of the pressure device can be used in turn, thus providing redundancy and improved reliability. The pressure device measurement range is 0 - 1025 hPa in temperature range of -45°C - +55°C, but its calibration is optimized for the Martian pressure range of 4 - 12 hPa. In support of the in situ measurements we have analyzed the atmospheric conditions at the MSL landing site at the Gale crater by utilizing mesoscale and limited area models. The compatibility of the results of these modeling tools with the actual environmental conditions will be discussed.

Validation of the Omron HEM-7201 upper arm blood pressure monitor, for self-measurement in a high-altitude environment, according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Cho, K; Tian, M; Lan, Y; Zhao, X; Yan, L L

2013-08-01

Few studies have been conducted on blood pressure monitors and their use at high altitude. This study is the first to evaluate the accuracy of an automatic blood pressure monitor in a high-altitude environment following a standard validation protocol. The Omron HEM-7201 upper arm blood pressure monitor was tested for accuracy in Lhasa, Tibet, China (3650 m above sea level) according to the European Society of Hypertension International Protocol revision 2010 (ESH-IP2). Thirty-three participants received 9-10 sequential blood pressure measurements alternating between a mercury sphygmomanometer and the device. The mean device-observer measurement difference was 1.0±5.9 mm Hg for systolic blood pressure (SBP) and -3.1±4.6 mm Hg for diastolic blood pressure (DBP). Of the 99 measurement pairs analyzed, 72, 90 and 97 device readings were within 5, 10 and 15 mm Hg, respectively, of the observer measurements for SBP, and 68, 92 and 99 readings for DBP. The number of participants with at least two out of three measurements within 5 mm Hg was 27 for SBP and 25 for DBP. Three participants had no measurements within 5 mm Hg for either SBP or DBP. As a result, the Omron HEM-7201 passes the ESH-IP2 validation criteria and can therefore be recommended for use in adults in this setting.

Integrated pressure and temperature sensor with high immunity against external disturbance for flexible endoscope operation

NASA Astrophysics Data System (ADS)

Maeda, Yusaku; Maeda, Kohei; Kobara, Hideki; Mori, Hirohito; Takao, Hidekuni

2017-04-01

In this study, an integrated pressure and temperature sensor device for a flexible endoscope with long-term stability in in vivo environments was developed and demonstrated. The sensor, which is embedded in the thin wall of the disposable endoscope hood, is intended for use in endoscopic surgery. The device surface is coated with a Cr layer to prevent photoelectronic generation induced by the strong light of the endoscope. The integrated temperature sensor allows compensation for the effect of the temperature drift on a pressure signal. The fabricated device pressure resolution is 0.4 mmHg; the corresponding pressure error is 3.2 mmHg. The packaged device was used in a surgical simulation in an animal experiment. Pressure and temperature monitoring was achieved even in a pH 1 acid solution. The device enables intraluminal pressure and temperature measurements of the stomach, which facilitate the maintenance of internal stomach conditions. The applicability of the sensor was successfully demonstrated in animal experiments.

Validation of the fully automated A&D TM-2656 blood pressure monitor according to the British Hypertension Society Protocol.

PubMed

Zeng, Wei-Fang; Liu, Ming; Kang, Yuan-Yuan; Li, Yan; Wang, Ji-Guang

2013-08-01

The present study aimed to evaluate the accuracy of the fully automated oscillometric upper-arm blood pressure monitor TM-2656 according to the British Hypertension Society (BHS) Protocol 1993. We recruited individuals until there were 85 eligible participants and their blood pressure could meet the blood pressure distribution requirements specified by the BHS Protocol. For each individual, we sequentially measured the systolic and diastolic blood pressures using a mercury sphygmomanometer (two observers) and the TM-2656 device (one supervisor). Data analysis was carried out according to the BHS Protocol. The device achieved grade A. The percentage of blood pressure differences within 5, 10, and 15 mmHg was 62, 85, and 96%, respectively, for systolic blood pressure, and 71, 93, and 99%, respectively, for diastolic blood pressure. The average (±SD) of the device-observer differences was -2.1±7.8 mmHg (P<0.0001) and -1.1±5.8 mmHg (P<0.0001) for systolic and diastolic blood pressures, respectively. The A&D upper-arm blood pressure monitor TM-2656 has passed the requirements of the BHS Protocol, and can thus be recommended for blood pressure measurement.

40 CFR 63.1452 - What are my monitoring requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... a flow sensor calibration check at least semiannually. (3) If a pressure measurement device is used...) through (v) of this section. (i) Locate the pressure sensor(s) in or as close to a position that provides a representative measurement of the pressure. (ii) Minimize or eliminate pulsating pressure...

Validation of the Kingyield BP210 wrist blood pressure monitor for home blood pressure monitoring according to the European Society of Hypertension-International Protocol.

PubMed

Zeng, Wei-Fang; Huang, Qi-Fang; Sheng, Chang-Sheng; Li, Yan; Wang, Ji-Guang

2012-02-01

The present study aimed to evaluate the accuracy of the automated oscillometric wrist blood pressure monitor BP210 for home blood pressure monitoring according to the International Protocol of the European Society of Hypertension. Systolic and diastolic blood pressures were sequentially measured in 33 adult Chinese participants (21 women, 51 years of mean age) using a mercury sphygmomanometer (two observers) and the BP210 device (one supervisor). Ninety-nine pairs of comparisons were obtained from 15 participants in phase 1 and a further 18 participants in phase 2 of the validation study. Data analysis was conducted using the ESHIP analyzer. The BP210 device successfully passed phase 1 of the validation study with a number of absolute differences between device and observers within 5, 10, and 15 mmHg for at least 33/45, 44/45, and 44/45 measurements, respectively. The device also achieved the targets for phase 2.1, with 77/99, 95/99, and 97/99 differences within 5, 10, and 15 mmHg, respectively for systolic blood pressure, and with 78/99, 97/99, and 99/99 within 5, 10, and 15 mmHg, respectively for diastolic blood pressure. In phase 2.2, 29 and 25 participants had at least two of the three device-observers differences within 5 mmHg (required≥22) for systolic blood pressure and diastolic blood pressure, respectively. The Kingyield wrist blood pressure monitor BP210 has passed the International Protocol requirements, and hence can be recommended for home use in adults.

Blood pressure variability of two ambulatory blood pressure monitors.

PubMed

Kallem, Radhakrishna R; Meyers, Kevin E C; Cucchiara, Andrew J; Sawinski, Deirdre L; Townsend, Raymond R

2014-04-01

There are no data on the evaluation of blood pressure (BP) variability comparing two ambulatory blood pressure monitoring monitors worn at the same time. Hence, this study was carried out to compare variability of BP in healthy untreated adults using two ambulatory BP monitors worn at the same time over an 8-h period. An Accutorr device was used to measure office BP in the dominant and nondominant arms of 24 participants.Simultaneous 8-h BP and heart rate data were measured in 24 untreated adult volunteers by Mobil-O-Graph (worn for an additional 16 h after removing the Spacelabs monitor) and Spacelabs with both random (N=12) and nonrandom (N=12) assignment of each device to the dominant arm. Average real variability (ARV), SD, coefficient of variation, and variation independent of mean were calculated for systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure (PP). Whether the Mobil-O-Graph was applied to the dominant or the nondominant arm, the ARV of mean systolic (P=0.003 nonrandomized; P=0.010 randomized) and PP (P=0.009 nonrandomized; P=0.005 randomized) remained significantly higher than the Spacelabs device, whereas the ARV of the mean arterial pressure was not significantly different. The average BP readings and ARVs for systolic blood pressure and PP obtained by the Mobil-O-Graph were considerably higher for the daytime than the night-time. Given the emerging interest in the effect of BP variability on health outcomes, the accuracy of its measurement is important. Our study raises concerns about the accuracy of pooling international ambulatory blood pressure monitoring variability data using different devices.

Variability in alignment of central venous pressure transducer to physiologic reference point in the intensive care unit-A descriptive and correlational study.

PubMed

Sjödin, Carl; Sondergaard, Soren; Johansson, Lotta

2018-06-01

The phlebostatic axis is the most commonly used anatomical external reference point for central venous pressure measurements. Deviation in the central venous pressure transducer alignment from the phlebostatic axis causes inadequate pressure readings, which may affect treatment decisions for critically ill patients in intensive care units. The primary aim of the study was to assess the variability in central venous pressure transducer levelling in the intensive care unit. We also assessed whether patient characteristics impacted on central venous pressure transducer alignment deviation. A sample of 61 critical care nurses was recruited and asked to place a transducer at the appropriate level for central venous pressure measurement. The measurements were performed in the intensive care unit on critically ill patients in supine and Fowler's positions. The variability among the participants using eyeball levelling and a laser levelling device was calculated in both sessions and adjusted for patient characteristics. A significant variation was found among critical care nurses in the horizontal levelling of the pressure transducer placement when measuring central venous pressure in the intensive care unit. Using a laser levelling device did not reduce the deviation from the phlebostatic axis. Patient characteristics had little impact on the deviation in the measurements. The anatomical external landmark for the phlebostatic axis varied between critical care nurses, as the variation in the central venous pressure transducer placement was not reduced with a laser levelling device. Standardisation of a zero-level for vascular pressures should be considered to reduce the variability in vascular pressure readings in the intensive care unit to improve patient treatment decisions. Further studies are needed to evaluate critical care nurses' knowledge and use of central venous pressure monitoring and whether assistive tools and/or routines can improve the accuracy in vascular pressure measurements in intensive care units. Copyright © 2018 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved.

Systems and methods for measuring component matching

NASA Technical Reports Server (NTRS)

Courter, Kelly J. (Inventor); Slenk, Joel E. (Inventor)

2006-01-01

Systems and methods for measuring a contour match between adjacent components are disclosed. In one embodiment, at least two pressure sensors are located between adjacent components. Each pressure sensor is adapted to obtain a pressure measurement at a location a predetermined distance away from the other pressure sensors, and to output a pressure measurement for each sensor location. An output device is adapted to receive the pressure measurements from at least two pressure sensors and display the pressure measurements. In one aspect, the pressure sensors include flexible thin film pressure sensors. In accordance with other aspects of the invention, a method is provided for measuring a contour match between two interfacing components including measuring at least one pressure applied to at least one sensor between the interfacing components.

Surface acoustic wave oxygen pressure sensor

NASA Technical Reports Server (NTRS)

Oglesby, Donald M. (Inventor); Upchurch, Billy T. (Inventor); Leighty, Bradley D. (Inventor)

1994-01-01

A transducer for the measurement of absolute gas-state oxygen pressure from pressures of less than 100 Pa to atmospheric pressure (1.01 x 10(exp 5) Pa) is based on a standard surface acoustic wave (SAW) device. The piezoelectric material of the SAW device is coated with a compound which will selectively and reversibly bind oxygen. When oxygen is bound by the coating, the mass of the coating increases by an amount equal to the mass of the bound oxygen. Such an increase in the mass of the coating causes a corresponding decrease in the resonant frequency of the SAW device.

Non-invasive method and apparatus for measuring pressure within a pliable vessel

NASA Technical Reports Server (NTRS)

Shimizu, M. (Inventor)

1983-01-01

A non-invasive method and apparatus is disclosed for measuring pressure within a pliable vessel such as a blood vessel. The blood vessel is clamped by means of a clamping structure having a first portion housing a pressure sensor and a second portion extending over the remote side of the blood vessel for pressing the blood vessel into engagement with the pressure sensing device. The pressure sensing device includes a flat deflectable diaphragm portion arranged to engage a portion of the blood vessel flattened against the diaphragm by means of the clamp structure. In one embodiment, the clamp structure includes first and second semicylindrical members held together by retaining rings. In a second embodiment the clamp structure is of one piece construction having a solid semicylindrical portion and a hollow semicylindrical portion with a longitudinal slot in the follow semicylindrical portion through which a slip the blood vessel. In a third embodiment, an elastic strap is employed for clamping the blood vessel against the pressure sensing device.

Accuracy and reliability of wrist-cuff devices for self-measurement of blood pressure.

PubMed

Kikuya, Masahiro; Chonan, Kenichi; Imai, Yutaka; Goto, Eiji; Ishii, Masao

2002-04-01

Self-measurement of blood pressure (BP) might offer some advantages in diagnosis and therapeutic evaluation and in patient management of hypertension. Recently, wrist-cuff devices for self-measurement of BP have gained more than one-third of the world market share. In the present study, we validated wrist-cuff devices and compared the results between wrist- and arm-cuff devices. The factors affecting the accuracy of wrist-cuff devices were also studied. The research group to assess the validity of automated blood pressure measuring device consisted of 13 institutes in Japan, which validated two wrist-cuff devices (WC-1 and WC-2) and two arm-cuff devices (AC-1 and AC-2). They used a crossover method, where the comparison was done between auscultation, by two observers by means of a double stethoscope on one arm and the device on the opposite arm or wrist. There was good inter-observer agreement for the auscultation method in each institute (systolic blood pressure (SBP), -0.1 +/- 2.8 mmHg; diastolic blood pressure (DBP), -0.1 +/- 2.6 mmHg, n = 498). The mean difference between auscultation and the device was minimal both in arm-cuff devices (mean difference for AC-1, 2.2/1.9 mmHg, n = 97 and for AC-2, 5.1/2.9 mmHg, n = 136, SBP/DBP) and wrist-cuff devices (mean difference for WC-1, -2.1/1.2 mmHg, n = 173 mmHg and for WC-2, -2.3/-5.6 mmHg, n = 92). The standard deviation of the difference (SDD) in wrist-cuff devices, however (SDD for WC-1, 9.7/7.3 mmHg and for WC-2, 10.2/8.6 mmHg), was larger than that of the arm-cuff devices (SDD for AC-1, 5.6/6.6 mmHg and for AC-2, 6.3/5.1 mmHg). Grading of AC-1 and AC-2 based on criteria of British Hypertension Society was A/A and B/A, respectively, while that of WC-1 and WC-2 was C/B and D/B, respectively. Using the same validation protocol, the results of validation for one device were divergent in each institute. In wrist-cuff devices, the BP value obtained in palmar flexion was significantly higher and that obtained in palmar dorsiflexion was significantly lower than that in palmar extension. In some cases, finger plethysmogram did not disappear during maximum inflation of the wrist-cuff (congruent with 250 mmHg), even in palmar extension and especially in palmar flexion, suggesting incomplete obstruction of radial and/or ulnar arteries during inflation. The results suggest that wrist-cuff devices in the present form are inadequate for self-measurement of blood pressure and, thus, are inadequate for general use or clinical and practical use. However, there is much possibility in wrist-cuff device and the accuracy and reliability of wrist-cuff device are warranted by an improvement of technology.

Left Atrial Pressure Monitoring With an Implantable Wireless Pressure Sensor After Implantation of a Left Ventricular Assist Device

PubMed Central

Baranowski, Jacek; Delshad, Baz; Ahn, Henrik

2017-01-01

After implantation of a continuous-flow left ventricular assist device (LVAD), left atrial pressure (LAP) monitoring allows for the precise management of intravascular volume, inotropic therapy, and pump speed. In this case series of 4 LVAD recipients, we report the first clinical use of this wireless pressure sensor for the long-term monitoring of LAP during LVAD support. A wireless microelectromechanical system pressure sensor (Titan, ISS Inc., Ypsilanti, MI) was placed in the left atrium in four patients at the time of LVAD implantation. Titan sensor LAP was measured in all four patients on the intensive care unit and in three patients at home. Ramped speed tests were performed using LAP and echocardiography in three patients. The left ventricular end-diastolic diameter (cm), flow (L/min), power consumption (W), and blood pressure (mm Hg) were measured at each step. Measurements were performed over 36, 84, 137, and 180 days, respectively. The three discharged patients had equipment at home and were able to perform daily recordings. There were significant correlations between sensor pressure and pump speed, LV and LA size and pulmonary capillary wedge pressure, respectively (r = 0.92–0.99, p < 0.05). There was no device failure, and there were no adverse consequences of its use. PMID:27676410

Prevention of Medical Device-Related Pressure Injuries Associated With Respiratory Equipment Use in a Critical Care Unit: A Quality Improvement Project.

PubMed

Padula, Cynthia A; Paradis, Heidi; Goodwin, Robert; Lynch, Judith; Hegerich-Bartula, Deborah

Medical devices have been identified as an extrinsic risk factor for development of pressure injuries, with as many as 30% to 70% of medical device-related pressure injuries resulting from respiratory equipment. This article describes a quality improvement project undertaken to reduce the occurrence of respiratory device-related pressure injuries in a critically care unit. Multiple actions were implemented to achieve this goal. Respiratory therapists were trained to document occurrences on a daily basis, and apparent cause analyses were conducted on each occurrence. An interdisciplinary team conducted biweekly rounds on patients with respiratory devices and consulted other professionals as indicated. Nurses and respiratory therapists attended an evidence-based, collaborative, educational offering and completed a measure of team functioning before the program and at the end of the study period. The occurrence rates of respiratory device-related pressure injuries were reduced over the project period, and these changes were sustained over the subsequent 12 months.

Inducer Hydrodynamic Load Measurement Devices

NASA Technical Reports Server (NTRS)

Skelley, Stephen E.; Zoladz, Thomas F.

2002-01-01

Marshall Space Flight Center (MSFC) has demonstrated two measurement devices for sensing and resolving the hydrodynamic loads on fluid machinery. The first - a derivative of the six component wind tunnel balance - senses the forces and moments on the rotating device through a weakened shaft section instrumented with a series of strain gauges. This "rotating balance" was designed to directly measure the steady and unsteady hydrodynamic loads on an inducer, thereby defining both the amplitude and frequency content associated with operating in various cavitation modes. The second device - a high frequency response pressure transducer surface mounted on a rotating component - was merely an extension of existing technology for application in water. MSFC has recently completed experimental evaluations of both the rotating balance and surface-mount transducers in a water test loop. The measurement bandwidth of the rotating balance was severely limited by the relative flexibility of the device itself, resulting in an unexpectedly low structural bending mode and invalidating the higher frequency response data. Despite these limitations, measurements confirmed that the integrated loads on the four-bladed inducer respond to both cavitation intensity and cavitation phenomena. Likewise, the surface-mount pressure transducers were subjected to a range of temperatures and flow conditions in a non-rotating environment to record bias shifts and transfer functions between the transducers and a reference device. The pressure transducer static performance was within manufacturer's specifications and dynamic response accurately followed that of the reference.

Inducer Hydrodynamic Load Measurement Devices

NASA Technical Reports Server (NTRS)

Skelley, Stephen E.; Zoladz, Thomas F.; Turner, Jim (Technical Monitor)

2002-01-01

Marshall Space Flight Center (MSFC) has demonstrated two measurement devices for sensing and resolving the hydrodynamic loads on fluid machinery. The first - a derivative of the six-component wind tunnel balance - senses the forces and moments on the rotating device through a weakened shaft section instrumented with a series of strain gauges. This rotating balance was designed to directly measure the steady and unsteady hydrodynamic loads on an inducer, thereby defining both the amplitude and frequency content associated with operating in various cavitation modes. The second device - a high frequency response pressure transducer surface mounted on a rotating component - was merely an extension of existing technology for application in water. MSFC has recently completed experimental evaluations of both the rotating balance and surface-mount transducers in a water test loop. The measurement bandwidth of the rotating balance was severely limited by the relative flexibility of the device itself, resulting in an unexpectedly low structural bending mode and invalidating the higher-frequency response data. Despite these limitations, measurements confirmed that the integrated loads on the four-bladed inducer respond to both cavitation intensity and cavitation phenomena. Likewise, the surface-mount pressure transducers were subjected to a range of temperatures and flow conditions in a non-rotating environment to record bias shifts and transfer functions between the transducers and a reference device. The pressure transducer static performance was within manufacturer's specifications and dynamic response accurately followed that of the reference.

Validation of the HONSUN LD-578 blood pressure monitor for home blood pressure monitoring according to the European Society of Hypertension International Protocol.

PubMed

Zhang, Yi; Wang, Jie; Huang, Qi-Fang; Sheng, Chang-Sheng; Li, Yan; Wang, Ji-Guang

2009-06-01

This study aimed to evaluate the accuracy of the automated oscillometric upper arm blood pressure monitor LD-578 (HONSUN Group, Shanghai, China) for home blood pressure monitoring according to the International Protocol. Systolic and diastolic blood pressures were sequentially measured in 33 adult Chinese using a mercury sphygmomanometer (two observers) and the LD-578 device (one supervisor). Ninety-nine pairs of comparisons were obtained from 15 participants in phase 1 and a further 18 participants in phase 2 of the validation study. Data analysis was performed using the ESHIP Analyzer. The LD-578 device successfully passed phase 1 of the validation study with a number of absolute differences between device and observers within 5, 10, and 15 mmHg for at least 32 of 45, 41 of 45, and 45 of 45 measurements (required 25, 35, and 40), respectively. The device also achieved the targets for phase 2.1, with 67 of 99, 90 of 99, and 98 of 99 differences within 5, 10, and 15 mmHg, respectively, for systolic blood pressure, and with 69 of 99, 95 of 99, and 98 of 99 within 5, 10, and 15 mmHg, respectively, for diastolic blood pressure. In phase 2.2, 24 participants had at least two of the three device-observers differences within 5 mmHg (required >or=22) for systolic and diastolic blood pressure. The HONSUN upper arm blood pressure monitor LD-578 can be recommended for home use in adults.

Validation of the BPLab(®) 24-hour blood pressure monitoring system according to the European standard BS EN 1060-4:2004 and British Hypertension Society protocol.

PubMed

Koudryavtcev, Sergey A; Lazarev, Vyacheslav M

2011-01-01

Automatic blood pressure (BP) measuring devices are more and more often used in BP self-checks and in 24-hour BP monitoring. Nowadays, 24-hour BP monitoring is a necessary procedure in arterial hypertension treatment. The aim of this study was to validate the BPLab(®) ambulatory blood pressure monitor according to the European standard BS EN 1060-4:2004 and the British Hypertension Society (BHS) protocol, as well as to work out solutions regarding the suitability of using this device in clinical practice. A group of 85 patients of both sexes and different ages, who voluntarily agreed to take part in the tests and were given detailed instructions on the measurement technique were recruited for this study. The results of the BP measurement obtained by a qualified operator using the BPLab(®) device were compared with the BP values measured using the Korotkov auscultatory method. Data were obtained simultaneously by two experts with experience of over 10 years and had completed a noninvasive BP measurement standardization training course. Discrepancies in the systolic and diastolic BP measurements (N = 510; 255 for each expert) were analyzed according to the criteria specified in the BHS-93 protocol. The device passed the requirements of the European Standard BS EN 1060-4:2004 and was graded 'A' according to the criteria of the BHS protocol for both systolic BP and diastolic BP. The BPLab(®) 24-hour ambulatory blood pressure monitoring device may be recommended for extensive clinical use.

A microfluidic circulatory system integrated with capillary-assisted pressure sensors.

PubMed

Chen, Yangfan; Chan, Ho Nam; Michael, Sean A; Shen, Yusheng; Chen, Yin; Tian, Qian; Huang, Lu; Wu, Hongkai

2017-02-14

The human circulatory system comprises a complex network of blood vessels interconnecting biologically relevant organs and a heart driving blood recirculation throughout this system. Recreating this system in vitro would act as a bridge between organ-on-a-chip and "body-on-a-chip" and advance the development of in vitro models. Here, we present a microfluidic circulatory system integrated with an on-chip pressure sensor to closely mimic human systemic circulation in vitro. A cardiac-like on-chip pumping system is incorporated in the device. It consists of four pumping units and passive check valves, which mimic the four heart chambers and heart valves, respectively. Each pumping unit is independently controlled with adjustable pressure and pump rate, enabling users to control the mimicked blood pressure and heartbeat rate within the device. A check valve is located downstream of each pumping unit to prevent backward leakage. Pulsatile and unidirectional flow can be generated to recirculate within the device by programming the four pumping units. We also report an on-chip capillary-assisted pressure sensor to monitor the pressure inside the device. One end of the capillary was placed in the measurement region, while the other end was sealed. Time-dependent pressure changes were measured by recording the movement of the liquid-gas interface in the capillary and calculating the pressure using the ideal gas law. The sensor covered the physiologically relevant blood pressure range found in humans (0-142.5 mmHg) and could respond to 0.2 s actuation time. With the aid of the sensor, the pressure inside the device could be adjusted to the desired range. As a proof of concept, human normal left ventricular and arterial pressure profiles were mimicked inside this device. Human umbilical vein endothelial cells (HUVECs) were cultured on chip and cells can respond to mechanical forces generated by arterial-like flow patterns.

Postural Effects on Intracranial Pressure as Assessed Noninvasively

NASA Technical Reports Server (NTRS)

Ueno, Toshiaki; Hargens, Alan R.; Ballard, R. E.; Shuer, L. M.; Cantrell, J. H.; Yost, W. T.; Holton, Emily M. (Technical Monitor)

1997-01-01

This study was designed to investigate effects of whole body tilting on intracranial compliance and pressure in six healthy volunteers by using a noninvasive ultrasonic device. Subjects were randomly tilted up or down sequentially at 60 degree, 30 degree head-up, supine, and 15 degree head-down position for one minute at each angle. We measured arterial blood pressure with a finger pressure cuff and changes in intracranial distance with an ultrasonic device. The device measures skull movement on the order of micro-meter. Our ultrasound technique demonstrates that skull movement is highly correlated (r$(circumflex){2}$=0.77) with intracranial pressure variations due to cerebral arterial pulsation. The amplitudes of arterial pressure (r$(circumflex){2}$=0.99 and those of intracranial distance changes (r$(circumflex){2}$=0.87) associated with one cardiac cycle were inversely correlated with the angle of tilt. The ratio of pulsation amplitudes for intracranial distance over arterial pressure also showed a significant increase as the angle of tilt was lowered (p=0.003). Thus, postural changes alter intracranial compliance in healthy volunteers and intracranial volume-buffering capacity is reduced in head-down position.

An anti-barotrauma system for preventing barotrauma during hyperbaric oxygen therapy.

PubMed

Song, Moon; Hoon, Se Jeon; Shin, Tae Min

2018-01-01

In the present study, a tympanometry-based anti-barotrauma (ABT) device was designed using eardrum admittance measurements to develop an objective method of preventing barotrauma that occurs during hyperbaric oxygen (HBO₂) therapy. The middle ear space requires active equalization, and barotrauma of these tissues during HBO₂therapy constitutes the most common treatment-associated injury. Decongestant nasal sprays and nasal steroids are used, but their efficacy is questionable to prevent middle ear barotrauma (MEB) during HBO₂ treatment. Accordingly, a tympanometry-based ABT device was designed using eardrum admittance measurements to develop an objective method for preventing MEB, which causes pain and injury, and represents one of the principal reasons for patients to stop treatment. This study was conducted to test a novel technology that can be used to measure transmembrane pressures, and provide chamber attendants with real-time feedback regarding the patient's equalization status prior to the onset of pain or injury. Eardrum admittance values were measured according to pressure changes inside a hyperbaric oxygen chamber while the system was fitted to the subject. When the pressure increased to above 200 daPa, eardrum admittance decreased to 16.255% of prepressurization levels. After pressure equalization was achieved, eardrum admittance recovered to 95.595% of prepressurization levels. A one-way repeated measures analysis of variance contrast test was performed on eardrum admittance before pressurization versus during pressurization, and before pressurization versus after pressure equalization. The analysis revealed significant differences at all points during pressurization (P⟨0.001), but no significant difference after pressure equalization was achieved. This ABT device can provide objective feedback reflecting eardrum condition to the patient and the chamber operator during HBO₂ therapy. Copyright© Undersea and Hyperbaric Medical Society.

Standard values of maximum tongue pressure taken using newly developed disposable tongue pressure measurement device.

PubMed

Utanohara, Yuri; Hayashi, Ryo; Yoshikawa, Mineka; Yoshida, Mitsuyoshi; Tsuga, Kazuhiro; Akagawa, Yasumasa

2008-09-01

It is clinically important to evaluate tongue function in terms of rehabilitation of swallowing and eating ability. We have developed a disposable tongue pressure measurement device designed for clinical use. In this study we used this device to determine standard values of maximum tongue pressure in adult Japanese. Eight hundred fifty-three subjects (408 male, 445 female; 20-79 years) were selected for this study. All participants had no history of dysphagia and maintained occlusal contact in the premolar and molar regions with their own teeth. A balloon-type disposable oral probe was used to measure tongue pressure by asking subjects to compress it onto the palate for 7 s with maximum voluntary effort. Values were recorded three times for each subject, and the mean values were defined as maximum tongue pressure. Although maximum tongue pressure was higher for males than for females in the 20-49-year age groups, there was no significant difference between males and females in the 50-79-year age groups. The maximum tongue pressure of the seventies age group was significantly lower than that of the twenties to fifties age groups. It may be concluded that maximum tongue pressures were reduced with primary aging. Males may become weaker with age at a faster rate than females; however, further decreases in strength were in parallel for male and female subjects.

Fluid flow monitoring device

DOEpatents

McKay, M.D.; Sweeney, C.E.; Spangler, B.S. Jr.

1993-11-30

A flow meter and temperature measuring device are described comprising a tube with a body centered therein for restricting flow and a sleeve at the upper end of the tube to carry several channels formed longitudinally in the sleeve to the appropriate axial location where they penetrate the tube to allow pressure measurements and temperature measurements with thermocouples. The high pressure measurement is made using a channel penetrating the tube away from the body and the low pressure measurement is made at a location at the widest part of the body. An end plug seals the end of the device and holes at its upper end allow fluid to pass from the interior of the tube into a plenum. The channels are made by cutting grooves in the sleeve, the grooves widened at the surface of the sleeve and then a strip of sleeve material is welded to the grooves closing the channels. Preferably the sleeve is packed with powdered graphite before cutting the grooves and welding the strips. 7 figures.

A new device for continuous monitoring the CO2 dissolved in water

NASA Astrophysics Data System (ADS)

de Gregorio, S.; Camarda, M.; Cappuzzo, S.; Giudice, G.; Gurrieri, S.; Longo, M.

2009-04-01

The measurements of dissolved CO2 in water are common elements of industrial processes and scientific research. In order to perform gas dissolved measurements is required to separate the dissolved gaseous phase from water. We developed a new device able to separate the gases phase directly in situ and well suitable for continuous measuring the CO2 dissolved in water. The device is made by a probe of a polytetrafluorethylene (PTFE) tube connected to an I.R. spectrophotometer (I.R.) and a pump. The PTFE is a polymeric semi-permeable membrane and allows the permeation of gas in the system. Hence, this part of the device is dipped in water in order to equilibrate the probe headspace with the dissolved gases. The partial pressure of the gas i in the headspace at equilibrium (Pi) follows the Henry's law: Pi=Hi•Ci, where Hi is the Henry's constant and Ci is the dissolved concentration of gas i. After the equilibrium is achieved, the partial pressure of CO2 inside the tube is equal to the partial pressure of dissolved CO2. The concentration of CO2 is measured by the I.R. connected to the tube. The gas is moved from the tube headspace to the I.R. by using the pump. In order to test the device and assess the best operating condition, several experimental were performed in laboratory. All the test were executed in a special apparatus where was feasible to create controlled atmospheres. Afterward the device has been placed in a draining tunnel sited in the Mt. Etna Volcano edifice (Italy). The monitored groundwater intercepts the Pernicana Fault, along which degassing phenomena are often observed. The values recorded by the station result in agreement with monthly directly measurements of dissolved CO2 partial pressure.

Assessment of sequential same arm agreement of blood pressure measurements by a CVProfilor DO-2020 versus a Baumanometer mercury sphygmomanometer.

PubMed

Prisant, L M; Resnick, L M; Hollenberg, S M

2001-06-01

The aim of this study was to assess the accuracy of sequential same arm blood pressure measurement by the mercury sphygmomanometer with the oscillometric blood pressure measurements from a device that also determines arterial elasticity. A prospective, multicentre, clinical study evaluated sequential same arm blood pressure measurements, using a mercury sphygmomanometer (Baumanometer, W. A. Baum Co., Inc., Copiague, New York, USA) and an oscillometric non-invasive device that calculates arterial elasticity (CVProfilor DO-2020 Cardiovascular Profiling System, Hypertension Diagnostics, Inc., Eagan, Minnesota, USA). Blood pressure was measured supine in triplicate, 3 min apart in a randomized sequence after a period of rest. The study population of 230 normotensive and hypertensive subjects included 57% females, 51% Caucasians, and 33% African Americans. The mean difference between test methods of systolic blood pressure, diastolic blood pressure, and heart rate was -3.2 +/- 6.9 mmHg, +0.8 +/- 5.9 mmHg, and +1.0 +/- 5.7 beats/minute. For systolic and diastolic blood pressure, 60.9 and 70.4% of sequential measurements by each method were within +/- 5 mmHg. Few or no points fell beyond the mean +/- 2 standard deviations lines for each cuff bladder size. Sequential same arm measurements of the CVProfilor DO-2020 Cardiovascular Profiling System measures blood pressure by an oscillometric method (dynamic linear deflation) with reasonable agreement with a mercury sphygmomanometer.

Performance Assessment of Active Hearing Protection Devices

DTIC Science & Technology

2015-05-08

8 Figure 6. Placement of ATFs and free -field pressure transducer ....................................... 8 Figure 7. Pressure-time history...devices selected for this study were all equipped with a hear-thru setting designed to amplify soft sounds and conversational speech while allowing loud...duration of an impulse noise A ¼” microphone or slender probe (tapered pencil gauge) was used to measure the free - field pressure wave according to the

Design and Development of a Pressure Transducer for High Hydrostatic Pressure Measurements up to 200 MPa

NASA Astrophysics Data System (ADS)

Kumar, Anuj; Yadav, Sanjay; Agarwal, Ravinder

2017-08-01

A number of pressure transducers, based on strain gauge, capacitance/inductance type, frequency resonators, are commercially available and are being used for sensing and producing an electrical output proportional to applied pressure. These sensors have their own advantages and limitations due to operational ease, measurement uncertainty and the costs. Strain gauge type transducers are now well established devices for accurate and precise measurement of pressure within measurement uncertainty up to 0.1 % of full scale. In the present research work, an indigenous strain gauge pressure transducer has been designed, developed, tested and calibrated for pressure measurement up to 200 MPa. The measurement uncertainty estimated using the pressure transducer was found better than 0.1 % of full scale. This transducer was developed using four foil type strain gauges, bonded, two in axial direction while other two in radial direction, to the controlled stress zones of a tubular maraging steel active cylinder working also as diaphragm. The strain gages were then connected to a Wheatstone bridge arrangement to measure stress generated strains. The pressure was applied through matching connector designed in the same tubular transducer active element. The threaded unique design in a single piece through collar, ferule and tubing arrangement provides leak proof pressure connections with external devices without using additional seals. The calibration and performance checking of the pressure transducer was carried out using dead weight type national pressure standard using the internationally accepted calibration procedure.

An oxygen pressure sensor using surface acoustic wave devices

NASA Technical Reports Server (NTRS)

Leighty, Bradley D.; Upchurch, Billy T.; Oglesby, Donald M.

1993-01-01

Surface acoustic wave (SAW) piezoelectric devices are finding widespread applications in many arenas, particularly in the area of chemical sensing. We have developed an oxygen pressure sensor based on coating a SAW device with an oxygen binding agent which can be tailored to provide variable sensitivity. The coating is prepared by dissolving an oxygen binding agent in a toluene solution of a copolymer which is then sprayed onto the surface of the SAW device. Experimental data shows the feasibility of tailoring sensors to measure the partial pressure of oxygen from 2.6 to 67 KPa (20 to 500 torr). Potential applications of this technology are discussed.

A programmable point-of-care device for external CSF drainage and monitoring.

PubMed

Simkins, Jeffrey R; Subbian, Vignesh; Beyette, Fred R

2014-01-01

This paper presents a prototype of a programmable cerebrospinal fluid (CSF) external drainage system that can accurately measure the dispensed fluid volume. It is based on using a miniature spectrophotometer to collect color data to inform drain rate and pressure monitoring. The prototype was machined with 1 μm dimensional accuracy. The current device can reliably monitor the total accumulated fluid volume, the drain rate, the programmed pressure, and the pressure read from the sensor. Device requirements, fabrication processes, and preliminary results with an experimental set-up are also presented.

New method for remote and repeatable monitoring of intraocular pressure variations.

PubMed

Margalit, Israel; Beiderman, Yevgeny; Skaat, Alon; Rosenfeld, Elkanah; Belkin, Michael; Tornow, Ralf-Peter; Mico, Vicente; Garcia, Javier; Zalevsky, Zeev

2014-02-01

We present initial steps toward a new measurement device enabling high-precision, noncontact remote and repeatable monitoring of intraocular pressure (IOP)-based on an innovative measurement principle. Using only a camera and a laser source, the device measures IOP by tracking the secondary speckle pattern trajectories produced by the reflection of an illuminating laser beam from the iris or the sclera. The device was tested on rabbit eyes using two different methods to modify IOP: via an infusion bag and via mechanical pressure. In both cases, the eyes were stimulated with increasing and decreasing ramps of the IOP. As IOP variations changed the speckle distributions reflected back from the eye, data were recorded under various optical configurations to define and optimize the best experimental configuration for the IOP extraction. The association between the data provided by our proposed device and that resulting from controlled modification of the IOP was assessed, revealing high correlation (R2=0.98) and sensitivity and providing a high-precision measurement (5% estimated error) for the best experimental configuration. Future steps will be directed toward applying the proposed measurement principle in clinical trials for monitoring IOP with human subjects.

Pressure Measurement Based on Thermocouples

NASA Astrophysics Data System (ADS)

Thomsen, K.

2010-12-01

Measuring gas pressures reliably in a harsh radiation environment was confirmed to be tricky during operation of the liquid spallation target of MEGAPIE at the Paul Scherrer Institute (PSI). Severe drift of calibration and the loss of a sensor were experienced. At the same time, the only instrumentation that worked flawlessly in the system were thermocouples. Motivated by this experience, a novel pressure sensor for application in high radiation fields has been developed, which is based on temperature measurement. The new sensor takes advantage of the fact that the thermal conductivity over a mechanical joint exhibits a strong dependence on the contact pressure. In the novel sensor heating is applied at one point and temperatures are measured at different specific locations of the pressure gage; in particular, the temperatures on the two sides of a mechanical contact are monitored. From the observed temperature distribution the gas pressure can be derived. By choosing specific mechanical details in the lay-out, it is possible to tailor the useful measurement range. In addition to yielding pressure values, the new sensor concept admits for obtaining a measure for the accuracy of the result. This is done by continuous self monitoring of the device. The health status and based thereupon the plausibility of the indicated pressure value can be deducted by comparing sensed temperatures to expectation values for any given heating power. Malfunctioning of the pressure gage is reliably detected from the diverse readings of only one device; this can be seen as providing internal redundancy while at the same time immunity to common mode failure. After some analytical and finite element studies to verify the concept in principle, a first prototype of such a novel pressure sensor has been built at PSI. Initial measurement campaigns demonstrated the correct operation of the device as anticipated. Further potential for optimization, like designing a gage for high temperature applications or the miniaturization of such sensors, has been revealed.

High-fidelity digital recording and playback sphygmomanometry system: device description and proof of concept.

PubMed

Lee, Jongshill; Chee, Youngjoon; Kim, Inyoung; Karpettas, Nikos; Kollias, Anastasios; Atkins, Neil; Stergiou, George S; O'Brien, Eoin

2015-10-01

This study describes the development of a new digital sphygmocorder (DS-II), which allows the digital recording and playback of the Korotkoff sounds, together with cuff pressure waveform, and its performance in a pilot validation study. A condenser microphone and stethoscope head detect Korotkoff sounds and an electronic chip, dedicated to audio-signal processing, is used to record high-quality sounds. Systolic and diastolic blood pressure (SBP/DBP) are determined from the recorded signals with an automatic beat detection algorithm that displays the cuff pressure at each beat on the monitor. Recordings of Korotkoff sounds, with the cuff pressure waveforms, and the simultaneous on-site assessments of SBP/DBP were performed during 100 measurements in 10 individuals. The observers reassessed the recorded signals to verify their accuracy and differences were calculated. The features of the high-fidelity DS-II, the technical specifications and the assessment procedures utilizing the playback software are described. Interobserver absolute differences (mean±SD) in measurements were 0.7±1.1/1.3±1.3 mmHg (SBP/DBP) with a mercury sphygmomanometer and 0.3±0.9/0.8±1.2 mmHg with the DS-II. The absolute DS-II mercury sphygmomanometer differences were 1.3±1.9/1.5±1.3 mmHg (SBP/DBP). The high-fidelity DS-II device presents satisfactory agreement with simultaneous measurements of blood pressure with a mercury sphygmomanometer. The device will be a valuable methodology for validating new blood pressure measurement technologies and devices.

46 CFR 160.151-45 - Equipment required for servicing facilities.

Code of Federal Regulations, 2010 CFR

2010-10-01

...); (d) Hot presses (if applicable); (e) Safety-type glue pots or equivalents; (f) Abrasive devices; (g..., or other pressure-measurement device or pressure gauge of equivalent accuracy and sensitivity; (j... liferafts, unless the facility services only non-davit-launched liferafts; (q) A supply of parts for all...

Non-invasive method and apparatus for monitoring intracranial pressure and pressure volume index in humans

NASA Technical Reports Server (NTRS)

Cantrell, John H. (Inventor); Yost, William T. (Inventor)

1994-01-01

Non-invasive measuring devices responsive to changes in a patient's intracranial pressure (ICP) can be accurately calibrated for monitoring purposes by providing known changes in ICP by non-invasive methods, such as placing the patient on a tilting bed and calculating a change in ICP from the tilt angle and the length of the patient's cerebrospinal column, or by placing a pressurized skull cap on the patient and measuring the inflation pressure. Absolute values for the patient's pressure-volume index (PVI) and the steady state ICP can then be determined by inducing two known changes in the volume of cerebrospinal fluid while recording the corresponding changes in ICP by means of the calibrated measuring device. The two pairs of data for pressure change and volume change are entered into an equation developed from an equation describing the relationship between ICP and cerebrospinal fluid volume. PVI and steady state ICP are then determined by solving the equation. Methods for inducing known changes in cerebrospinal fluid volume are described.

Non-invasive method and apparatus for monitoring intracranial pressure and pressure volume index in humans

NASA Technical Reports Server (NTRS)

Yost, William T. (Inventor); Cantrell, Jr., John H. (Inventor)

1997-01-01

Non-invasive measuring devices responsive to changes in a patient's intracranial pressure (ICP) can be accurately calibrated for monitoring purposes by providing known changes in ICP by non-invasive methods, such as placing the patient on a tilting bed and calculating a change in ICP from the tilt angle and the length of the patient's cerebrospinal column, or by placing a pressurized skull cap on the patient and measuring the inflation pressure. Absolute values for the patient's pressure-volume index (PVI) and the steady state ICP can then be determined by inducing two known changes in the volume of cerebrospinal fluid while recording the corresponding changes in ICP by means of the calibrated measuring device. The two pairs of data for pressure change and volume change are entered into an equation developed from an equation describing the relationship between ICP and cerebrospinal fluid volume. PVI and steady state ICP are then determined by solving the equation. Methods for inducing known changes in cerebrospinal fluid volume are described.

Oscillometric estimation of central blood pressure: validation of the Mobil-O-Graph in comparison with the SphygmoCor device.

PubMed

Weiss, Wolfgang; Gohlisch, Christopher; Harsch-Gladisch, Christl; Tölle, Markus; Zidek, Walter; van der Giet, Markus

2012-06-01

Hypertension is a major risk factor for a wide range of cardiovascular diseases and is typically identified by measuring blood pressure (BP) at the brachial artery. Although such a measurement may accurately determine diastolic BP, systolic BP is not reflected accurately. Current noninvasive techniques for assessing central aortic BP require additional recording of an arterial pressure wave using a high-fidelity applanation tonometer. Within one measurement cycle, the Mobil-O-Graph BP device uses brachial oscillometric BP waves for a noninvasive estimation of central BP. We therefore validated the Mobil-O-Graph against the SphygmoCor device, which is widely known as the commonly used approach for a noninvasive estimation of central BP. For each individual, we compared three readings of the central BP values obtained by the Mobil-O-Graph and SphygmoCor device consecutively. One hundred individuals (mean age 56.1 ± 15.4 years) were recruited for measurement.Differences between the central BP values of the test device and the SphygmoCor device were calculated for each measurement. The mean difference (95% confidence interval) for the estimated central systolic BP between both devices was -0.6 ± 3.7 mmHg. Comparison of the central BP values measured by the two devices showed a statistically significant linear correlation (R=0.91, P<0.0001). The mean between-method difference was 0.50 mmHg for central systolic BP estimation. The intrarater reproducibility between both the devices was also comparable. Bland and Altman analyses showed that the mean differences (95% confidence interval) between repeated measurements were 1.89 (0.42-3.36) mmHg and 1.36 (-0.16 to 2.83) mmHg for the SphygmoCor and the Mobil-O-Graph device, respectively. Thus, neither of these differences was statistically significantly different from 0. The limits of agreement were -16.34 to 19.73 and -15.23 to 17.17 mmHg for the SphygmoCor and the Mobil-O-Graph device, respectively. Oscillometric noninvasive estimation of central BP with the Mobil-O-Graph BP device is as effective as using the well-established SphygmoCor applanation tonometry device. In comparison, the Mobil-O-Graph combines the widespread benefits of brachial BP measurement and also provides central BP within one measurement.

Phacoemulsification tip vacuum pressure: Comparison of 4 devices.

PubMed

Payne, Marielle; Georgescu, Dan; Waite, Aaron N; Olson, Randall J

2006-08-01

To determine the vacuum pressure generated by 4 phacoemulsification devices measured at the phacoemulsification tip. University ophthalmology department. The effective vacuum pressures generated by the Sovereign (AMO), Millennium (Bausch & Lomb), Legacy AdvanTec (Alcon Laboratories), and Infiniti (Alcon Laboratories) phacoemulsification machines were measured with a device that isolated the phacoemulsification tip in a chamber connected to a pressure gauge. The 4 machines were tested at multiple vacuum limit settings, and the values were recorded after the foot pedal was fully depressed and the pressure had stabilized. The AdvanTec and Infiniti machines were tested with and without occlusion of the Aspiration Bypass System (ABS) side port (Alcon Laboratories). The Millennium machine was tested using venturi and peristaltic pumps. The machines generated pressures close to the expected at maximum vacuum settings between 100 mm Hg and 500 mm Hg with few intermachine variations. There was no significant difference between pressures generated using 19- or 20-gauge tips (Millennium and Sovereign). The addition of an ABS side port decreased vacuum by a mean of 12.1% (P < .0001). Although there were some variations in vacuum pressures among phacoemulsification machines, particularly when an aspiration bypass tip was used, these discrepancies are probably not clinically significant.

Carbon nanotube vacuum gauges utilizing long, dissipative tubes

NASA Astrophysics Data System (ADS)

Kaul, Anupama B.; Manohara, Harish M.

2008-04-01

A carbon nanotube-based thermal conductivity vacuum gauge is described which utilizes 5-10 μm long diffusively contacted SWNTs for vacuum sensing. By etching the thermal SiO II beneath the tubes and minimizing heat conduction through the substrate, pressure sensitivity was extended toward higher vacuums. The pressure response of unannealed and annealed devices was compared to that of released devices. The released devices showed sensitivity to pressure as low as 1 x 10 -6 Torr. The sensitivity increased more dramatically with power for the released device compared to that of the unreleased device. Low temperature electronic transport measurements of the tubes were suggestive of a thermally activated hopping mechanism where the activation energy for hopping was calculated to be ~ 39 meV.

Testing a Method for Quantifying the Output of Implantable Middle Ear Hearing Devices

PubMed Central

Rosowski, J.J.; Chien, W.; Ravicz, M.E.; Merchant, S.N.

2008-01-01

This report describes tests of a standard practice for quantifying the performance of implantable middle ear hearing devices (also known as implantable hearing aids). The standard and these tests were initiated by the Food and Drug Administration of the United States Government. The tests involved measurements on two hearing devices, one commercially available and the other home built, that were implanted into ears removed from human cadavers. The tests were conducted to investigate the utility of the practice and its outcome measures: the equivalent ear canal sound pressure transfer function that relates electrically driven middle ear velocities to the equivalent sound pressure needed to produce those velocities, and the maximum effective ear canal sound pressure. The practice calls for measurements in cadaveric ears in order to account for the varied anatomy and function of different human middle ears. PMID:17406105

21 CFR 868.1780 - Inspiratory airway pressure meter.

Code of Federal Regulations, 2010 CFR

2010-04-01

... meter. (a) Identification. An inspiratory airway pressure meter is a device used to measure the amount of pressure produced in a patient's airway during maximal inspiration. (b) Classification. Class II...

21 CFR 868.1750 - Pressure plethysmograph.

Code of Federal Regulations, 2010 CFR

2010-04-01

...) Identification. A pressure plethysmograph is a device used to determine a patient's airway resistance and lung volumes by measuring pressure changes while the patient is in an airtight box. (b) Classification. Class...

A PDA-based electrocardiogram/blood pressure telemonitor for telemedicine.

PubMed

Bolanos, Marcos; Nazeran, Homayoun; Gonzalez, Izzac; Parra, Ricardo; Martinez, Christopher

2004-01-01

An electrocardiogram (ECG) / blood pressure (BP) telemonitor consisting of comprehensive integration of various electrical engineering concepts, devices, and methods was developed. This personal digital assistant-based (PDAbased) system focused on integration of biopotential amplifiers, photoplethysmographic measurement of blood pressure, microcontroller devices, programming methods, wireless transmission, signal filtering and analysis, interfacing, and long term memory devices (24 hours) to develop a state-of-the-art ECG/BP telemonitor. These instrumentation modules were developed and tested to realize a complete and compact system that could be deployed to assist in telemedicine applications and heart rate variability studies. The specific objective of this device was to facilitate the long term monitoring and recording of ECG and blood pressure signals. This device was able to acquire ECG/BP waveforms, transmit them wirelessly to a PDA, save them onto a compact flash memory, and display them on the LCD screen of the PDA. It was also capable of calculating the heart rate (HR) in beats per minute, and providing systolic and diastolic blood pressure values.

Falls event detection using triaxial accelerometry and barometric pressure measurement.

PubMed

Bianchi, Federico; Redmond, Stephen J; Narayanan, Michael R; Cerutti, Sergio; Celler, Branko G; Lovell, Nigel H

2009-01-01

A falls detection system, employing a Bluetooth-based wearable device, containing a triaxial accelerometer and a barometric pressure sensor, is described. The aim of this study is to evaluate the use of barometric pressure measurement, as a surrogate measure of altitude, to augment previously reported accelerometry-based falls detection algorithms. The accelerometry and barometric pressure signals obtained from the waist-mounted device are analyzed by a signal processing and classification algorithm to discriminate falls from activities of daily living. This falls detection algorithm has been compared to two existing algorithms which utilize accelerometry signals alone. A set of laboratory-based simulated falls, along with other tasks associated with activities of daily living (16 tests) were performed by 15 healthy volunteers (9 male and 6 female; age: 23.7 +/- 2.9 years; height: 1.74 +/- 0.11 m). The algorithm incorporating pressure information detected falls with the highest sensitivity (97.8%) and the highest specificity (96.7%).

SU-E-J-48: Development of An Abdominal Compression Device for Respiratory Correlated Radiation Therapy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, T; Kang, S; Kim, D

Purpose: The aim of this study is to develop the abdominal compression device which could control pressure level according to the abdominal respiratory motion and evaluate its feasibility. Methods: In this study, we focused on developing the abdominal compression device which could control pressure level at any point of time so the developed device is possible to use a variety of purpose (gating technique or respiratory training system) while maintaining the merit of the existing commercial device. The compression device (air pad form) was designed to be able to compress the front and side of abdomen and the pressure levelmore » of the abdomen is controlled by air flow. Pressure level of abdomen (air flow) was determined using correlation data between external abdominal motion and respiratory volume signal measured by spirometer. In order to verify the feasibility of the device, it was necessary to confirm the correlation between the abdominal respiratory motion and respiratory volume signal and cooperation with respiratory training system also checked. Results: In the previous study, we could find that the correlation coefficient ratio between diaphragm and respiratory volume signal measured by spirometer was 0.95. In this study, we confirmed the correlation between the respiratory volume signal and the external abdominal motion measured by belt-transducer (correlation coefficient ratio was 0.92) and used the correlated respiratory volume data as an abdominal pressure level. It was possible to control the pressure level with negligible time delay and respiratory volume data based guiding waveforms could be properly inserted into the respiratory training system. Conclusion: Through this feasibility study, we confirmed the correlation between the respiratory volume signal and the external abdominal motion. Also initial assessment of the device and its compatibility with the respiratory training system were verified. Further study on application in respiratory gated therapy and respiratory training system will be investigated. This work was supported by Radiation Technology R and D program (No. 2013M2A2A7043498)and Basic Atomic Energy Research Institute (BAERI)(No. NRF-2009-0078390) through the National Research Foundation of Korea funded by the Ministry of Science, ICT and Future Planning.« less

A simple technique for measurement of pressure in the tympanitic rumen of cattle.

PubMed

Turner, C B; Whyte, T D

1978-05-13

The construction and method of use of a simple device for the non-invasive measurement of intra-rumenal pressure is outlined. Results obtained from calves suffering from increased intra-rumenal pressure (bloat) are shown. The method is capable of quantifying pressures involved in bloat and could be used to augment the visual assessment of bloat scoring.

Nonmagnetic high pressure cell for magnetic remanence measurements up to 1.5 GPa in a superconducting quantum interference device magnetometer.

PubMed

Sadykov, Ravil A; Bezaeva, Natalia S; Kharkovskiy, Alexander I; Rochette, Pierre; Gattacceca, Jérome; Trukhin, Vladimir I

2008-11-01

We describe here a compact nonmagnetic composite high pressure cell of piston-cylinder type with inner diameter of 6 mm equipped with manganin pressure sensor. This cell was developed for room temperature measurements of magnetic remanence of relatively large rock samples (up to 5.8 mm in diameter and 15 mm long cylinders) under hydrostatic pressure up to 1.5 GPa (the operating pressure limit) in the 2G Enterprises superconducting quantum interference device magnetometer. Its design was focused on minimizing the remanent magnetic moment m(r) of the cell (m(r)=3 x 10(-8) A m(2)) that allowed direct measurements of remanent magnetic moment M(r) under pressure for weakly magnetic materials-rock samples (M(r) epsilon[5 x 10(-7),10(-4)] A m(2)). The inner part of this composite cell is made of hard "Russian alloy" (Ni(57)Cr(40)Al(3)) whereas the envelope of the cell corps is made of less magnetic titanium alloy. This design solution permitted to reduce the total remanent magnetic moment of the whole cell and represents the main device feature. We describe here the choice of materials for pressure cell based on their magnetic and mechanical properties, the choice of the pressure transmitting medium (polyethilsiloxane liquid) providing perfectly hydrostatic conditions for the sample as well as the cell geometry. The cell performance is illustrated by results of pressure demagnetization experiments on rocks and minerals.

Development of Personalized Fitting Device With 3-Dimensional Solution for Prevention of NIV Oronasal Mask-Related Pressure Ulcers.

PubMed

Shikama, Maiko; Nakagami, Gojiro; Noguchi, Hiroshi; Mori, Taketoshi; Sanada, Hiromi

2018-05-22

Pressure ulcers related to oronasal masks used with noninvasive ventilation (NIV), along with patient discomfort, occur due to improper fit of the mask. We developed a personalized fitting device using a 3-dimensional (3D) scanning solution to prevent the formation of NIV mask-related pressure ulcers. This study aimed to evaluate the effectiveness of the proposed personalized fitting device. We conducted a randomized crossover experimental study of 20 healthy participants to study the use of this personalized fitting device between the face and an NIV mask designed with 3D solutions. The fitting device was not used under the NIV mask for the control. The outcome measures were the presence of blanchable erythema, standardized redness intensity, discomfort level, and contact pressure. The incidence of blanchable erythema and standardized redness intensity values were significantly lower for subjects who used the fitting device when worn for 30 min ( P < .001). The discomfort levels at the forehead, nasal bridge, and both cheeks, as well as leakage, were significantly reduced as well ( P = .008, P < .001, P = .001, P = .002, P = .001, P = .02, P < .001, P < .001, P < .001). Contact pressure at the nasal bridge, where pressure ulcers most frequently develop, was significantly decreased with the fitting device ( P < .001). Personalized fitting devices that incorporate 3D scanning solutions may contribute to the prevention of NIV mask-related pressure ulcers and the reduction of discomfort. Copyright © 2018 by Daedalus Enterprises.

Biofouling detection monitoring devices: status assessment. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hillman, R.E.; Anson, D.; Corliss, J.M.

1985-03-01

An inventory of devices to detect and monitor biofouling in power plant condenser systems was prepared. The inventory was developed through a review of manufacturers' product information brochures, a general literature review, and limited personal contact with users and manufacturers. Two macrofouling and seventeen microfouling detection devices were reviewed. A summary analysis of the principal features of each device was prepared. Macrofouling devices are generally simple devices located at or near cooling water intakes. They monitor the growth of larger organisms such as mussels, barnacles, and large seaweeds. Microfouling detectors are usually located in or near the condenser tubes. Theymore » detect and monitor the growth of slime films on the tubes. Some of the devices measure changes in heat transfer or pressure drop in the condenser tubes. Other types include condenser simulators, biofilm samplers, or devices that measure the acoustic properties of the fouling films. Most devices are still in the development stage. Of the few available for general use, the type that measures heat transfer and/or pressure drop are developed to a greater degree than the other types. Recommendations for further research into development of a biofouling detection and monitoring devices include a side-by-side field comparison of selected devices, and the continued development of an effective acoustic device.« less

Practice parameters for the use of autotitrating continuous positive airway pressure devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome: an update for 2007. An American Academy of Sleep Medicine report.

PubMed

Morgenthaler, Timothy I; Aurora, R Nisha; Brown, Terry; Zak, Rochelle; Alessi, Cathy; Boehlecke, Brian; Chesson, Andrew L; Friedman, Leah; Kapur, Vishesh; Maganti, Rama; Owens, Judith; Pancer, Jeffrey; Swick, Todd J

2008-01-01

These practice parameters are an update of the previously published recommendations regarding the use of autotitrating positive airway pressure (APAP) devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome. Continuous positive airway pressure (CPAP) at an effective setting verified by attended polysomnography is a standard treatment for obstructive sleep apnea (OSA). APAP devices change the treatment pressure based on feedback from various patient measures such as airflow, pressure fluctuations, or measures of airway resistance. These devices may aid in the pressure titration process, address possible changes in pressure requirements throughout a given night and from night to night, aid in treatment of OSA when attended CPAP titration has not or cannot be accomplished, or improve patient comfort. A task force of the Standards of Practice Committee of the American Academy of Sleep Medicine has reviewed the literature published since the 2002 practice parameter on the use of APAP. Current recommendations follow: (1) APAP devices are not recommended to diagnose OSA; (2) patients with congestive heart failure, patients with significant lung disease such as chronic obstructive pulmonary disease; patients expected to have nocturnal arterial oxyhemoglobin desaturation due to conditions other than OSA (e.g., obesity hypoventilation syndrome); patients who do not snore (either naturally or as a result of palate surgery); and patients who have central sleep apnea syndromes are not currently candidates for APAP titration or treatment; (3) APAP devices are not currently recommended for split-night titration; (4) certain APAP devices may be used during attended titration with polysomnography to identify a single pressure for use with standard CPAP for treatment of moderate to severe OSA; (5) certain APAP devices may be initiated and used in the self-adjusting mode for unattended treatment of patients with moderate to severe OSA without significant comorbidities (CHF, COPD, central sleep apnea syndromes, or hypoventilation syndromes); (6) certain APAP devices may be used in an unattended way to determine a fixed CPAP treatment pressure for patients with moderate to severe OSA without significant comorbidities (CHF, COPD, central sleep apnea syndromes, or hypoventilation syndromes); (7) patients being treated with fixed CPAP on the basis of APAP titration or being treated with APAP must have close clinical follow-up to determine treatment effectiveness and safety; and (8) a reevaluation and, if necessary, a standard attended CPAP titration should be performed if symptoms do not resolve or the APAP treatment otherwise appears to lack efficacy.

Measuring systolic ankle and toe pressure using the strain gauge technique--a comparison study between mercury and indium-gallium strain gauges.

PubMed

Broholm, Rikke; Wiinberg, Niels; Simonsen, Lene

2014-09-01

Measurement of the ankle and toe pressures are often performed using a plethysmograph, compression cuffs and a strain gauge. Usually, the strain gauge contains mercury but other alternatives exist. From 2014, the mercury-containing strain gauge will no longer be available in the European Union. The aim of this study was to compare an indium-gallium strain gauge to the established mercury-containing strain gauge. Consecutive patients referred to the Department of Clinical Physiology and Nuclear Medicine at Bispebjerg and Frederiksberg Hospitals for measurements of systolic ankle and toe pressures volunteered for the study. Ankle and toe pressures were measured twice with the mercury and the indium-gallium strain gauge in random order. Comparison of the correlation between the mean pressure using the mercury and the indium-gallium device and the difference between the two devices was performed for both toe and ankle level. A total of 53 patients were included (36 male). Mean age was 69 (range, 45-92 years). Mean pressures at toe and ankle level with the mercury and the indium-gallium strain gauges were 77 (range, 0-180) mm Hg and 113 (range, 15-190) mm Hg, respectively. Comparison between the mercury and the indium-gallium strain gauge showed a difference in toe blood pressure values of - 0.7 mm Hg (SD: 7.0). At the ankle level, a difference of 2.0 mm Hg (SD: 8.6) was found. The two different devices agree sufficiently in the measurements of systolic ankle and toe pressure for the indium-gallium strain gauge to replace the mercury strain gauge.

Detection of essential hypertension with physiological signals from wearable devices.

PubMed

Ghosh, Arindam; Torres, Juan Manuel Mayor; Danieli, Morena; Riccardi, Giuseppe

2015-08-01

Early detection of essential hypertension can support the prevention of cardiovascular disease, a leading cause of death. The traditional method of identification of hypertension involves periodic blood pressure measurement using brachial cuff-based measurement devices. While these devices are non-invasive, they require manual setup for each measurement and they are not suitable for continuous monitoring. Research has shown that physiological signals such as Heart Rate Variability, which is a measure of the cardiac autonomic activity, is correlated with blood pressure. Wearable devices capable of measuring physiological signals such as Heart Rate, Galvanic Skin Response, Skin Temperature have recently become ubiquitous. However, these signals are not accurate and are prone to noise due to different artifacts. In this paper a) we present a data collection protocol for continuous non-invasive monitoring of physiological signals from wearable devices; b) we implement signal processing techniques for signal estimation; c) we explore how the continuous monitoring of these physiological signals can be used to identify hypertensive patients; d) We conduct a pilot study with a group of normotensive and hypertensive patients to test our techniques. We show that physiological signals extracted from wearable devices can distinguish between these two groups with high accuracy.

UV emissions from artificial tanning devices and their compliance with the European technical standard.

PubMed

Facta, Stefania; Fusette, Stefania Saudino; Bonino, Alessandro; Anglesio, Laura; d'Amore, Giovanni

2013-04-01

Use of ultraviolet radiation-emitting tanning devices has been classified as "carcinogenic to humans" (group 1) by the International Agency for Research on Cancer. Following this classification, the knowledge of typical ultraviolet emission levels from tanning devices can be of interest for evaluating their impact on health. In this work, the results of an extensive measurement campaign on artificial tanning appliances are presented. Ultraviolet emissions from 94 tanning appliances produced by 15 different manufacturers were characterized by onsite spectroradiometric measurements. The measured radiometric quantities were compared with reference values fixed in the European technical standard EN 60335-2-27 "Household and similar electrical appliances-Safety. Part 2: Particular requirements for appliances for skin exposure to ultraviolet and infrared radiation." Measurement results indicate that 88% of the examined appliances had ultraviolet emissions not compliant with the technical standard. Among the considered appliances, tanning devices equipped with low pressure lamps showed higher ultraviolet levels of effective irradiance and less compliance with standard requirements. In particular, UV emissions from 100% of low pressure appliances and from 78% of high pressure appliances exceeded the irradiance limit of 0.3 Wm set by the European technical standard.

Fluid-flow pressure measurements and thermo-fluid characterization of a single loop two-phase passive heat transfer device

NASA Astrophysics Data System (ADS)

Ilinca, A.; Mangini, D.; Mameli, M.; Fioriti, D.; Filippeschi, S.; Araneo, L.; Roth, N.; Marengo, M.

2017-11-01

A Novel Single Loop Pulsating Heat Pipe (SLPHP), with an inner diameter of 2 mm, filled up with two working fluids (Ethanol and FC-72, Filling Ratio of 60%), is tested in Bottom Heated mode varying the heating power and the orientation. The static confinement diameter for Ethanol and FC-72, respectively 3.4 mm and 1.7mm, is above and slightly under the inner diameter of the tube. This is important for a better understanding of the working principle of the device very close to the limit between the Loop Thermosyphon and Pulsating Heat Pipe working modes. With respect to previous SLPHP experiments found in the literature, such device is designed with two transparent inserts mounted between the evaporator and the condenser allowing direct fluid flow visualization. Two highly accurate pressure transducers permit local pressure measurements just at the edges of one of the transparent inserts. Additionally, three heating elements are controlled independently, so as to vary the heating distribution at the evaporator. It is found that peculiar heating distributions promote the slug/plug flow motion in a preferential direction, increasing the device overall performance. Pressure measurements point out that the pressure drop between the evaporator and the condenser are related to the flow pattern. Furthermore, at high heat inputs, the flow regimes recorded for the two fluids are very similar, stressing that, when the dynamic effects start to play a major role in the system, the device classification between Loop Thermosyphon and Pulsating Heat Pipe is not that sharp anymore.

21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure gauge is a device used in cardiopulmonary bypass surgery to measure the pressure of the blood perfusing... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass coronary pressure gauge...

21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure gauge is a device used in cardiopulmonary bypass surgery to measure the pressure of the blood perfusing... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass coronary pressure gauge...

21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure gauge is a device used in cardiopulmonary bypass surgery to measure the pressure of the blood perfusing... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass coronary pressure gauge...

21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure gauge is a device used in cardiopulmonary bypass surgery to measure the pressure of the blood perfusing... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass coronary pressure gauge...

21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure gauge is a device used in cardiopulmonary bypass surgery to measure the pressure of the blood perfusing... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass coronary pressure gauge...

Using Smartphone Pressure Sensors to Measure Vertical Velocities of Elevators, Stairways, and Drones

ERIC Educational Resources Information Center

Monteiro, Martín; Martí, Arturo C.

2017-01-01

We measure the vertical velocities of elevators, pedestrians climbing stairs, and drones (flying unmanned aerial vehicles), by means of smartphone pressure sensors. The barometric pressure obtained with the smartphone is related to the altitude of the device via the hydrostatic approximation. From the altitude values, vertical velocities are…

High pressure stopped-flow apparatus for the rapid mixing and subsequent study of two fluids under high hydrostatic pressures

NASA Astrophysics Data System (ADS)

Karan, Daniel M.; Macey, Robert I.

1980-08-01

A stopped-flow apparatus is described for the rapid mixing and subsequent study of two dissimilar fluids under pressures up to 1200 bar. The device consists of two identical pressure chambers which contain the two fluids, a third pressure chamber which contains gas to maintain the pressure in the system, an optical port for photometric observation, and various connections. The device has been used to measure reaction times on the order of a hundred milliseconds to tens of seconds, using a maximum of 2 ml of each reagent per experimental determination. The dead time is found to be 5-25 ms with minium average flow velocities of 2.0 m/s. The construction and operation of the device are described and examples of water transport data in red blood cells and the bromophenolblue indicated chemical reaction of NaHCO3 and HCl under pressure are presented.

Validation of Plantar Pressure Measurements for a Novel In-Shoe Plantar Sensory Replacement Unit

PubMed Central

Ferber, Reed; Webber, Talia; Kin, B; Everett, Breanne; Groenland, Marcel

2013-01-01

Background Research concerning prevention of diabetic foot complications is critical. A novel in-shoe plantar sensory replacement unit (PSRU) has been developed that provides alert-based feedback derived from analyzing plantar pressure threshold measurements in real time. The purpose of this study was to compare the PSRU device to a gold standard pressure-sensing device (GS-PSD) to determine the correlation between concurrent measures of plantar pressure during walking. Methods The PSRU had an array of eight sensors with a range of 10–75 mm Hg and collected data at 4 Hz, whereas the GS-PSD had 99 sensors with a range of 1–112 mm Hg and collected data at 100 Hz. Based on an a priori power analysis, data were collected from 10 participants (3 female, 7 male) while walking over ground in both devices. The primary variable of interest was the number of data points recorded that were greater than 32 mm Hg (capillary arterial pressure—the minimum pressure reported to cause pressure ulcers) for each of the eight PSRU sensors and corresponding average recordings from the GS-PSD sensor clusters. Intraclass correlation coefficient (2,1) was used to compare data between the two devices. Results Compared with the GS-PSD, we found good-to-very-good correlations (r-value range 0.67–0.86; p-value range 0.01–0.05) for six of the PSRU’s eight sensors and poor correlation for only two sensors (r = 0.41, p = .15; r = 0.38, p = .18) when measuring the number of data points recorded that were greater than 32 mm Hg. Conclusions Based on the results of the present study, we conclude the PSRU provides analogous data when compared with a GS-PSD. PMID:24124942

Development, validity and reliability of a new pressure air biofeedback device (PAB) for measuring isometric extension strength of the lumbar spine.

PubMed

Pienaar, Andries W; Barnard, Justhinus G

2017-04-01

This study describes the development of a new portable muscle testing device, using air pressure as a biofeedback and strength testing tool. For this purpose, a pressure air biofeedback device (PAB ® ) was developed to measure and record the isometric extension strength of the lumbar multifidus muscle in asymptomatic and low back pain (LBP) persons. A total of 42 subjects (age 47.58 years, ±18.58) participated in this study. The validity of PAB ® was assessed by comparing a selected measure, air pressure force in millibar (mb), to a standard criterion; calibrated weights in kilograms (kg) during day-to-day tests. Furthermore, clinical trial-to-trial and day-to-day tests of maximum voluntary isometric contraction (MVIC) of L5 lumbar multifidus were done to compare air pressure force (mb) to electromyography (EMG) in microvolt (μV) and to measure the reliability of PAB ® . A highly significant relationship were found between air pressure output (mb) and calibrated weights (kg). In addition, Pearson correlation calculations showed a significant relationship between PAB ® force (mb) and EMG activity (μV) for all subjects (n = 42) examined, as well as for the asymptomatic group (n = 24). No relationship was detected for the LBP group (n = 18). In terms of lumbar extension strength, we found that asymptomatic subjects were significantly stronger than LBP subjects. The results of the PAB ® test differentiated between LBP and asymptomatic subject's lumbar isometric extension strength without any risk to the subjects and also indicate that the lumbar isometric extension test with the new PAB ® device is reliable and valid.

Effect of variable body mass on plantar foot pressure and off-loading device efficacy.

PubMed

Pirozzi, Kelly; McGuire, James; Meyr, Andrew J

2014-01-01

An increasing body of evidence has implicated obesity as having a negative effect on the development, treatment, and outcome of lower extremity pathologic entities, including diabetic foot disease. The objective of the present study was to increase the body of knowledge with respect to the effects of obesity on foot function. Specifically, we attempted to (1) describe the relationship between an increasing body mass index (BMI) on plantar foot pressures during gait, and (2) evaluate the efficacy of commonly prescribed off-loading devices with an increasing BMI. A repeated measures design was used to compare the peak plantar foot pressures under multiple test conditions, with the volunteers acting as their own controls. The primary outcome measure was the mean peak plantar pressure in the heel, midfoot, forefoot, and first metatarsal, and the 2 variables were modification of patient weight (from "normal" BMI to "overweight," "obese," and "morbidly obese") and footwear (from an athletic sneaker to a surgical shoe, controlled ankle motion walker, and total contact cast). Statistically significant increases in the peak plantar pressures were observed with increasing volunteer BMI weight class, regardless of the off-loading device used. The present investigation has provided unique and specific data with respect to the changes that occur in the peak plantar pressures with variable BMIs across different anatomic levels and with commonly used off-loading devices. From our results, we have concluded that although the plantar pressures increase with increasing weight, it appears that at least some reduction in pressure can be achieved with an off-loading device, most effectively with the total contact cast, regardless of the patient's BMI. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

All-optical non-mechanical fiber-coupled sensor for liquid- and airborne sound detection.

NASA Astrophysics Data System (ADS)

Rohringer, Wolfgang; Preißer, Stefan; Fischer, Balthasar

2017-04-01

Most fiber-optic devices for pressure, strain or temperature measurements are based on measuring the mechanical deformation of the optical fiber by various techniques. While excellently suited for detecting strain, pressure or structure-borne sound, their sensitivity to liquid- and airborne sound is so far not comparable with conventional capacitive microphones or piezoelectric hydrophones. Here, we present an all-optical acoustic sensor which relies on the detection of pressure-induced changes of the optical refractive index inside a rigid, millimeter-sized, fiber-coupled Fabry-Pérot interferometer (FPI). No mechanically movable or deformable parts take part in the signal transduction chain. Therefore, due to the absence of mechanical resonances, this sensing principle allows for high sensitivity as well as a flat frequency response over an extraordinary measurement bandwidth. As a fiber-coupled device, it can be integrated easily into already available distributed fiber-optic networks for geophysical sensing. We present characterization measurements demonstrating the sensitivity, frequency response and directivity of the device for sound and ultrasound detection in air and water. We show that low-frequency temperature and pressure drifts can be recorded in addition to acoustic sensing. Finally, selected application tests of the laser-based hydrophone and microphone implementation are presented.

Expert panel consensus recommendations for home blood pressure monitoring in Asia: the Hope Asia Network.

PubMed

Park, Sungha; Buranakitjaroen, Peera; Chen, Chen-Huan; Chia, Yook-Chin; Divinagracia, Romeo; Hoshide, Satoshi; Shin, Jinho; Siddique, Saulat; Sison, Jorge; Soenarta, Arieska Ann; Sogunuru, Guru Prasad; Tay, Jam Chin; Turana, Yuda; Wang, Ji-Guang; Zhang, Yuqing; Kario, Kazuomi

2018-04-01

Hypertension is the leading cause of mortality throughout Asia. Home blood pressure monitoring has the potential to improve hypertension control and is a useful adjunct to conventional office blood pressure measurements due to its diagnostic accuracy and prognostic value in predicting cardiovascular outcomes. At present, there are no region-specific guidelines addressing the use of home blood pressure monitoring in Asia. Therefore, an expert panel was convened to address the use of home blood pressure monitoring and develop key recommendations to help guide clinical practice throughout the Asia region. The resulting recommendations support the use of home blood pressure monitoring with a validated device as an accurate adjunct for diagnosing hypertension and predicting cardiovascular outcome. Diagnosis and treatment of hypertension should still be guided by conventional office/clinic blood pressure measurements. The expert panel encourages the incorporation of home blood pressure monitoring into local clinical guidelines and offers practical recommendations to ensure continuity of care where a validated home blood pressure device is not available.

Stroke Volume estimation using aortic pressure measurements and aortic cross sectional area: Proof of concept.

PubMed

Kamoi, S; Pretty, C G; Chiew, Y S; Pironet, A; Davidson, S; Desaive, T; Shaw, G M; Chase, J G

2015-08-01

Accurate Stroke Volume (SV) monitoring is essential for patient with cardiovascular dysfunction patients. However, direct SV measurements are not clinically feasible due to the highly invasive nature of measurement devices. Current devices for indirect monitoring of SV are shown to be inaccurate during sudden hemodynamic changes. This paper presents a novel SV estimation using readily available aortic pressure measurements and aortic cross sectional area, using data from a porcine experiment where medical interventions such as fluid replacement, dobutamine infusions, and recruitment maneuvers induced SV changes in a pig with circulatory shock. Measurement of left ventricular volume, proximal aortic pressure, and descending aortic pressure waveforms were made simultaneously during the experiment. From measured data, proximal aortic pressure was separated into reservoir and excess pressures. Beat-to-beat aortic characteristic impedance values were calculated using both aortic pressure measurements and an estimate of the aortic cross sectional area. SV was estimated using the calculated aortic characteristic impedance and excess component of the proximal aorta. The median difference between directly measured SV and estimated SV was -1.4ml with 95% limit of agreement +/- 6.6ml. This method demonstrates that SV can be accurately captured beat-to-beat during sudden changes in hemodynamic state. This novel SV estimation could enable improved cardiac and circulatory treatment in the critical care environment by titrating treatment to the effect on SV.

Accuracy of the Omron HEM-705 CP for blood pressure measurement in large epidemiologic studies.

PubMed

Vera-Cala, Lina M; Orostegui, Myriam; Valencia-Angel, Laura I; López, Nahyr; Bautista, Leonelo E

2011-05-01

Accurate measurement of blood pressure is of utmost importance in hypertension research. In the context of epidemiologic and clinical studies, oscillometric devices offer important advantages to overcome some of the limitations of the auscultatory method. Even though their accuracy has been evaluated in multiple studies in the clinical setting, there is little evidence of their performance in large epidemiologic studies. We evaluated the accuracy of the Omron HEM-705-CP, an automatic device for blood pressure (BP) measurement, as compared to the standard auscultatory method with a mercury sphygmomanometer in a large cohort study. We made three auscultatory measurements, followed by two measurements with the Omron device in 1,084 subjects. Bias was estimated as the average of the two Omron minus the average of the last two auscultatory measurements, with its corresponding 95% limits of agreement (LA). The Omron overestimated systolic blood pressure (SBP) by 1.8 mmHg (LA:-10.1, 13.7) and underestimated diastolic blood pressure (DBP) by 1.6 mmHg (LA:-12.3, 9.2). Bias was significantly larger in men. Bias in SBP increased with age and decreased with BP level, while bias in DBP decreased with age and increased with BP level. The sensitivity and specificity of the Omron to detect hypertension were 88.2% and 98.6%, respectively. Minimum bias in the estimates of the effects of several factors resulted from the use of Omron measurements. Our results showed that the Omron HEM-705-CP could be used for measuring BP in large epidemiology studies without compromising study validity or precision.

Noninvasive continuous blood pressure monitoring by the ClearSight system during robot-assisted laparoscopic radical prostatectomy.

PubMed

Sakai, Yoko; Yasuo M, Tsutsumi; Oyama, Takuro; Murakami, Chiaki; Kakuta, Nami; Tanaka, Katsuya

2018-01-01

Robot-assisted laparoscopic radical prostatectomy (RALRP) is commonly performed in the surgical treatment of prostate cancer. However, the steep Trendelenburg position (25) and pneumoperitoneum required for this procedure can sometimes cause hemodynamic changes. Although blood pressure is traditionally monitored invasively during RALRP, the ClearSight system (BMEYE, Amsterdam, The Netherlands) enables a totally noninvasive and simple continuous blood pressure and cardiac output monitoring based on finger arterial pressure pulse contour analysis. We therefore investigated whether noninvasive continuous arterial blood pressure measurements using the ClearSight system were comparable to those obtained invasively in patients undergoing RALRP. Ten patients scheduled for RALRP with American Society of Anesthesiologists physical status I-II were included in this study. At each of the seven defined time points, noninvasive and invasive blood pressure measurements were documented and compared in each patient using Bland-Altman analysis. Although the blood pressure measured with the ClearSight system correlated with that measured invasively, a large difference between the values obtained by the two devices was noted. The ClearSight system was unable to detect blood pressure accurately during RALRP, suggesting that blood pressure monitoring using this device alone is not feasible in this small patient population. J. Med. Invest. 65:69-73, February, 2018.

Plantar pressure measurements and running-related injury: A systematic review of methods and possible associations.

PubMed

Mann, Robert; Malisoux, Laurent; Urhausen, Axel; Meijer, Kenneth; Theisen, Daniel

2016-06-01

Pressure-sensitive measuring devices have been identified as appropriate tools for measuring an array of parameters during running. It is unclear which biomechanical characteristics relate to running-related injury (RRI) and which data-processing techniques are most promising to detect this relationship. This systematic review aims to identify pertinent methodologies and characteristics measured using plantar pressure devices, and to summarise their associations with RRI. PubMed, Embase, CINAHL, ScienceDirect and Scopus were searched up until March 2015. Retrospective and prospective, biomechanical studies on running using any kind of pressure-sensitive device with RRI as an outcome were included. All studies involving regular or recreational runners were considered. The study quality was assessed and the measured parameters were summarised. One low quality, two moderate quality and five high quality studies were included. Five different subdivisions of plantar area were identified, as well as five instants and four phases of measurement during foot-ground contact. Overall many parameters were collated and subdivided as plantar pressure and force, plantar pressure and force location, contact area, timing and stride parameters. Differences between the injured and control group were found for mediolateral and anteroposterior displacement of force, contact area, velocity of force displacement, relative force-time integral, mediolateral force ratio, time to peak force and inter-stride correlative patterns. However, no consistent results were found between studies and no biomechanical risk patterns were apparent. Additionally, conflicting findings were reported for peak force in three studies. Based on these observations, we provide suggestions for improved methodology measurement of pertinent parameters for future studies. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Pressure-assisted fabrication of organic light emitting diodes with MoO{sub 3} hole-injection layer materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, J.; Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544; Anye, V. C.

2014-06-21

In this study, pressures of ∼5 to ∼8 MPa were applied to organic light emitting diodes containing either evaporated molybdenum trioxide (MoO{sub 3}) or spin-coated poly(3,4-ethylene dioxythiophene) doped with poly(styrene sulphonate) (PEDOT:PSS) hole-injection layers (HILs). The threshold voltages for both devices were reduced by about half, after the application of pressure. Furthermore, in an effort to understand the effects of pressure treatment, finite element simulations were used to study the evolution of surface contact between the HIL and emissive layer (EML) under pressure. The blister area due to interfacial impurities was also calculated. This was shown to reduce by about half,more » when the applied pressures were between ∼5 and 8 MPa. The finite element simulations used Young's modulus measurements of MoO{sub 3} that were measured using the nanoindentation technique. They also incorporated measurements of the adhesion energy between the HIL and EML (measured by force microscopy during atomic force microscopy). Within a fracture mechanics framework, the implications of the results are then discussed for the pressure-assisted fabrication of robust organic electronic devices.« less

Validation of four devices: Omron M6 Comfort, Omron HEM-7420, Withings BP-800, and Polygreen KP-7670 for home blood pressure measurement according to the European Society of Hypertension International Protocol.

PubMed

Topouchian, Jirar; Agnoletti, Davide; Blacher, Jacques; Youssef, Ahmed; Chahine, Mirna N; Ibanez, Isabel; Assemani, Nathalie; Asmar, Roland

2014-01-01

Four oscillometric devices, including the Omron M6 Comfort, Omron HEM-7420, Withings BP-800, and Polygreen KP-7670, designed for self-blood pressure measurement (SBPM) were evaluated according to the European Society of Hypertension (ESH) International Protocol Revision 2010 in four separate studies. The four devices measure brachial blood pressure (BP) using the oscillometric method. The Withings BP-800 has to be connected to an Apple® iOS device such as an iPhone®, iPad®, or iPod®. The ESH International Protocol Revision 2010 includes a total number of 33 subjects. The difference between observer and device BP values was calculated for each measure. Ninety-nine pairs of BP differences were classified into three categories (≤5 mmHg, ≤10 mmHg, ≤15 mmHg). The protocol procedures were followed precisely in each of the four studies. All four tested devices passed the validation process. The mean differences between the device and mercury readings were: -1.8±5.1 mmHg and -0.4±2.8 mmHg for systolic and diastolic BP, respectively, using the Omron M6 Comfort device; 2.5±4.6 mmHg and -1.2±4.3 mmHg for the Omron HEM-7420 device; -0.2±5.0 mmHg and 0.4±4.2 mmHg for the Withings BP-800 device; and 3.0±5.3 mmHg and 0.3±5.2 mmHg for the Polygreen KP-7670 device. Omron M6 Comfort, Omron HEM-7420, Withings BP-800, and Polygreen KP-7670 readings differing by less than 5 mmHg, 10 mmHg, and 15 mmHg fulfill the ESH International Protocol Revision 2010 requirements, and therefore are suitable for use by patients for SBPM, if used correctly.

Practice Parameters for the Use of Autotitrating Continuous Positive Airway Pressure Devices for Titrating Pressures and Treating Adult Patients with Obstructive Sleep Apnea Syndrome: An Update for 2007

PubMed Central

Morgenthaler, Timothy I.; Aurora, R. Nisha; Brown, Terry; Zak, Rochelle; Alessi, Cathy; Boehlecke, Brian; Chesson, Andrew L.; Friedman, Leah; Kapur, Vishesh; Maganti, Rama; Owens, Judith; Pancer, Jeffrey; Swick, Todd J.

2008-01-01

These practice parameters are an update of the previously published recommendations regarding the use of autotitrating positive airway pressure (APAP) devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome. Continuous positive airway pressure (CPAP) at an effective setting verified by attended polysomnography is a standard treatment for obstructive sleep apnea (OSA). APAP devices change the treatment pressure based on feedback from various patient measures such as airflow, pressure fluctuations, or measures of airway resistance. These devices may aid in the pressure titration process, address possible changes in pressure requirements throughout a given night and from night to night, aid in treatment of OSA when attended CPAP titration has not or cannot be accomplished, or improve patient comfort. A task force of the Standards of Practice Committee of the American Academy of Sleep Medicine has reviewed the literature published since the 2002 practice parameter on the use of APAP. Current recommendations follow: (1) APAP devices are not recommended to diagnose OSA; (2) patients with congestive heart failure, patients with significant lung disease such as chronic obstructive pulmonary disease; patients expected to have nocturnal arterial oxyhemoglobin desaturation due to conditions other than OSA (e.g., obesity hypoventilation syndrome); patients who do not snore (either naturally or as a result of palate surgery); and patients who have central sleep apnea syndromes are not currently candidates for APAP titration or treatment; (3) APAP devices are not currently recommended for split-night titration; (4) certain APAP devices may be used during attended titration with polysomnography to identify a single pressure for use with standard CPAP for treatment of moderate to severe OSA; (5) certain APAP devices may be initiated and used in the self-adjusting mode for unattended treatment of patients with moderate to severe OSA without significant comorbidities (CHF, COPD, central sleep apnea syndromes, or hypoventilation syndromes); (6) certain APAP devices may be used in an unattended way to determine a fixed CPAP treatment pressure for patients with moderate to severe OSA without significant comorbidities (CHF, COPD, central sleep apnea syndromes, or hypoventilation syndromes); (7) patients being treated with fixed CPAP on the basis of APAP titration or being treated with APAP must have close clinical follow-up to determine treatment effectiveness and safety; and (8) a reevaluation and, if necessary, a standard attended CPAP titration should be performed if symptoms do not resolve or the APAP treatment otherwise appears to lack efficacy. Citation: Morgenthaler TI; Aurora RN; Brown T; Zak R; Alessi C; Boehlecke B; Chesson AL; Friedman L; Kapur V; Maganti R; Owens J; Pancer J; Swick TJ; Standards of Practice Committee of the AASM. Practice parameters for the use of autotitrating continuous positive airway pressure devices for titrating pressures and treating adult patients with obstructive sleep apnea syndrome: An update for 2007. SLEEP 2008;31(1):141-147. PMID:18220088

Validation of the Konsung QD217A for clinical use and self-measurement according to the European Society of Hypertension International Protocol.

PubMed

Wu, Ning; Zhang, Xuezhong; Wang, Wen; Zhang, Hongye

2015-08-01

This study aimed to evaluate the accuracy of the automated oscillometric upper arm blood pressure (BP) monitor Konsung QD217A for home BP monitoring according to the European Society of Hypertension International Protocol revision 2010. Three trained observers validated the performance of these devices by comparing the measurements obtained from these devices with those taken using a standard mercury sphygmomanometer. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were sequentially measured in 33 participants using a standard mercury sphygmomanometer and the Konsung QD217A device. A total of 99 pairs of comparisons were obtained from 33 participants. The QD217A device achieved the targets in part 1 of the validation study. The number of absolute differences between the device and the observers within a range of 5, 10 and 15 mmHg was 70/99, 92/99 and 96/99, respectively, for SBP and 80/99, 94/99 and 99/99, respectively, for DBP. The device also achieved the targets in part 2 of the validation study. A total of 27 and 31 participants for SBP and DBP, respectively, showed at least two of the three device-observers differences within 5 mmHg (required≥24). The number of participants without device-observer difference within 5 mmHg was one for SBP and one for DBP (required≤3). The Konsung upper arm BP monitor QD217A has passed the International Protocol requirements and it can be recommended for clinical use and self-measurement in adults. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Measurements of the Exerted Pressure by Pelvic Circumferential Compression Devices

PubMed Central

Knops, Simon P; van Riel, Marcel P.J.M; Goossens, Richard H.M; van Lieshout, Esther M.M; Patka, Peter; Schipper, Inger B

2010-01-01

Background: Data on the efficacy and safety of non-invasive Pelvic Circumferential Compression Devices (PCCDs) is limited. Tissue damage may occur if a continuous pressure on the skin exceeding 9.3 kPa is sustained for more than two or three hours. The aim of this study was to gain insight into the pressure build-up at the interface, by measuring the PCCD-induced pressure when applying pulling forces to three different PCCDs (Pelvic Binder® , SAM-Sling ® and T-POD® ) in a simplified model. Methods: The resulting exerted pressures were measured at four ‘anatomical’ locations (right, left, posterior and anterior) in a model using a pressure measurement system consisting of pressure cuffs. Results: The exerted pressure varied substantially between the locations as well as between the PCCDs. Maximum pressures ranged from 18.9-23.3 kPa and from 19.2-27.5 kPa at the right location and left location, respectively. Pressures at the posterior location stayed below 18 kPa. At the anterior location pressures varied markedly between the different PCCDs. Conclusion: The circumferential compression by the different PCCDs showed high pressures measured at the four locations using a simplified model. Difference in design and functional characteristics of the PCCDs resulted in different pressure build-up at the four locations. When following the manufacturer’s instructions, the exerted pressure of all three PCCDs tested exceeded the tissue damaging level (9.3 kPa). In case of prolonged use in a clinical situation this might put patients at risk for developing tissue damage. PMID:20361001

Automated intracranial pressure-controlled cerebrospinal fluid external drainage with LiquoGuard.

PubMed

Linsler, Stefan; Schmidtke, Mareike; Steudel, Wolf Ingo; Kiefer, Michael; Oertel, Joachim

2013-08-01

LiquoGuard is a new device for intracranial pressure (ICP)-controlled drainage of cerebrospinal fluid (CSF). This present study evaluates the accuracy of ICP measurement via the LiquoGuard device in comparison with Spiegelberg. Thus, we compared data ascertained from simultaneous measurement of ICP using tip-transducer and tip-sensor devices. A total of 1,764 monitoring hours in 15 patients (range, 52-219 h) were analysed. All patients received an intraventricular Spiegelberg III probe with the drainage catheter connected to the LiquoGuard system. ICP reading of both devices was performed on an hourly basis. Statistical analysis was done by applying Pearson correlation and Wilcoxon-matched pair test (p < 0.05). Mean ICP values were 11 ± 5 mmHg (Spiegelberg) and 10 ± 7 mmHg (LiquoGuard); the values measured with both devices correlated well (p = 0.001; Pearson correlation =0.349; n = 1,764). In two of the 15 patients with slit ventricles, episodes of significant differences in measured values could be observed. Both patients suffering from slit ventricles failed to produce reliable measurement with the external transducer of the LiquoGuard. LiquoGuard is a valuable new device for ICP-controlled CSF drainage. However, LiquoGuard tends to provide misleading results in slit ventricles. Thus, before these drawbacks are further analysed, the authors recommend additional ICP measurement with internal tip-sensor devices to avoid dangerous erroneous interpretation of ICP data.

Laboratory evaluation of the pressure water level data logger manufactured by Infinities USA, Inc.: results of pressure and temperature tests

USGS Publications Warehouse

Carnley, Mark V.

2015-01-01

The Pressure Water Level Data Logger manufactured by Infinities USA, Inc., was evaluated by the U.S. Geological Survey (USGS) Hydrologic Instrumentation Facility for conformance with the manufacturer’s stated accuracy specifications for measuring pressure throughout the device’s operating temperature range and with the USGS accuracy requirements for water-level measurements. The Pressure Water Level Data Logger (Infinities Logger) is a submersible, sealed, water-level sensing device with an operating pressure range of 0 to 11.5 feet of water over a temperature range of −18 to 49 degrees Celsius. For the pressure range tested, the manufacturer’s accuracy specification of 0.1 percent of full scale pressure equals an accuracy of ±0.138 inch of water. Three Infinities Loggers were evaluated, and the testing procedures followed and results obtained are described in this report. On the basis of the test results, the device is poorly compensated for temperature. For the three Infinities Loggers, the mean pressure differences varied from –4.04 to 5.32 inches of water and were not within the manufacturer’s accuracy specification for pressure measurements made within the temperature-compensated range. The device did not meet the manufacturer’s stated accuracy specifications for pressure within its temperature-compensated operating range of –18 to 49 degrees Celsius or the USGS accuracy requirements of no more than 0.12 inch of water (0.01 foot of water) or 0.10 percent of reading, whichever is larger. The USGS accuracy requirements are routinely examined and reported when instruments are evaluated at the Hydrologic Instrumentation Facility. The estimated combined measurement uncertainty for the pressure cycling test was ±0.139 inch of water, and for temperature, the cycling test was ±0.127 inch of water for the three Infinities Loggers.

Validation of the AVITA BPM15S wrist blood pressure monitor for home blood pressure monitoring according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Kang, Yuan-Yuan; Zeng, Wei-Fang; Zhang, Lu; Li, Yan; Wang, Ji-Guang

2014-06-01

The present study aimed to evaluate the accuracy of the automated oscillometric wrist blood pressure monitor AVITA BPM15S for home blood pressure monitoring according to the International Protocol revision 2010 of the European Society of Hypertension. Systolic and diastolic blood pressures were sequentially measured in 33 Chinese adults (15 women, mean age 51 years) using a mercury sphygmomanometer (two observers) and the AVITA BPM15S device (one supervisor). Ninety-nine pairs of comparisons were obtained from 33 participants for judgments in two parts with three grading phases. The AVITA BPM15S device achieved the targets in part 1 of the validation study. The number of absolute differences between the device and observers within 5, 10, and 15 mmHg were 85/99, 94/99, and 98/99, respectively, for systolic blood pressure, and 82/99, 96/99, and 98/99, respectively, for diastolic blood pressure. The device also achieved the criteria in part 2 of the validation study. Thirty-two and 28 participants for systolic and diastolic blood pressure, respectively, had at least two of the three device-observer differences within 5 mmHg (required ≥ 24). No participant had all of the three device-observer comparisons greater than 5 mmHg for systolic or diastolic blood pressure. The AVITA wrist blood pressure monitor BPM15S fulfilled the requirements of the International Protocol revision 2010 and hence can be recommended for home use in an adult population.

Validation of the SCIAN LD-735 wrist blood pressure monitor for home blood pressure monitoring according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Kang, Yuan-Yuan; Chen, Qi; Li, Yan; Wang, Ji-Guang

2016-08-01

This study aimed to evaluate the accuracy of the automated oscillometric wrist blood pressure monitor SCIAN LD-735 for home blood pressure monitoring according to the International Protocol of the European Society of Hypertension revision 2010. Systolic and diastolic blood pressures were measured sequentially in 33 adult Chinese participants (10 women, mean age 44.8 years) using a mercury sphygmomanometer (two observers) and the SCIAN LD-735 device (one supervisor). A total of 99 pairs of comparisons were obtained from 33 participants for judgments in two parts with three grading phases. The SCIAN LD-735 device achieved the targets in part 1 of the validation study. The number of absolute differences between device and observers within 5, 10, and 15 mmHg was 86/99, 97/99, and 98/99, respectively, for systolic blood pressure and 85/99, 98/99, and 99/99, respectively, for diastolic blood pressure. The device also fulfilled the criteria in part 2 of the validation study. In total, 30 and 33 participants for systolic and diastolic blood pressure, respectively, had at least two of the three device-observer differences within 5 mmHg (required ≥24). No participant had all of the three device-observer comparisons greater than 5 mmHg for systolic or diastolic blood pressure. The SCIAN wrist blood pressure monitor LD-735 has passed the requirements of the International Protocol revision 2010, and hence can be recommended for home use in adults.

Validation of the AVITA BPM17 wrist blood pressure monitor for home blood pressure monitoring according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Kang, Yuan-Yuan; Chen, Qi; Liu, Chang-Yuan; Li, Yan; Wang, Ji-Guang

2017-08-01

The aim of the present study was to evaluate the accuracy of the automated oscillometric wrist blood pressure monitor AVITA BPM17 for home blood pressure monitoring according to the International Protocol of the European Society of Hypertension revision 2010. Systolic and diastolic blood pressures were sequentially measured in 33 adult Chinese (19 men, 45.7 years of mean age) using a mercury sphygmomanometer (two observers) and the AVITA BPM17 device (one supervisor). Ninety-nine pairs of comparisons were obtained from 33 participants for judgments in two parts with three grading phases. The AVITA BPM17 device achieved the targets in part 1 of the validation study. The number of absolute differences between device and observers within 5, 10, and 15 mmHg was 94/99, 98/99, and 98/99, respectively, for systolic blood pressure and 92/99, 99/99, and 99/99, respectively, for diastolic blood pressure. The device also fulfilled the criteria in part 2 of the validation study. Overall, 32 participants for both systolic and diastolic blood pressure, respectively, had at least two of the three device-observerss differences within 5 mmHg (required ≥24). None had all the three device-observers comparisons greater than 5 mmHg for systolic and diastolic blood pressure. The AVITA wrist blood pressure monitor BPM17 has passed the requirements of the International Protocol revision 2010, and hence can be recommended for home use in adults.

Design and Implementation of an Underwater Sound Recording Device

PubMed Central

Martinez, Jayson J.; Myers, Josh R.; Carlson, Thomas J.; Deng, Z. Daniel; Rohrer, John S.; Caviggia, Kurt A.; Woodley, Christa M.; Weiland, Mark A.

2011-01-01

To monitor the underwater sound and pressure waves generated by anthropogenic activities such as underwater blasting and pile driving, an autonomous system was designed to record underwater acoustic signals. The underwater sound recording device (USR) allows for connections of two hydrophones or other dynamic pressure sensors, filters high frequency noise out of the collected signals, has a gain that can be independently set for each sensor, and allows for 2 h of data collection. Two versions of the USR were created: a submersible model deployable to a maximum depth of 300 m, and a watertight but not fully submersible model. Tests were performed on the USR in the laboratory using a data acquisition system to send single-frequency sinusoidal voltages directly to each component. These tests verified that the device operates as designed and performs as well as larger commercially available data acquisition systems, which are not suited for field use. On average, the designed gain values differed from the actual measured gain values by about 0.35 dB. A prototype of the device was used in a case study to measure blast pressures while investigating the effect of underwater rock blasting on juvenile Chinook salmon and rainbow trout. In the case study, maximum positive pressure from the blast was found to be significantly correlated with frequency of injury for individual fish. The case study also demonstrated that the device withstood operation in harsh environments, making it a valuable tool for collecting field measurements. PMID:22164089

TexiCare: an innovative embedded device for pressure ulcer prevention. Preliminary results with a paraplegic volunteer.

PubMed

Chenu, Olivier; Vuillerme, Nicolas; Bucki, Marek; Diot, Bruno; Cannard, Francis; Payan, Yohan

2013-08-01

This paper introduces the recently developed TexiCare device that aims at preventing pressure ulcers for people with spinal cord injury. This embedded device is aimed to be mounted on the user wheelchair. Its sensor is 100% textile and allows the measurement of pressures at the interface between the cushion and the buttocks. It is comfortable, washable and low cost. It is connected to a cigarette-box sized unit that (i) measures the pressures in real time, (ii) estimates the risk for internal over-strains, and (iii) alerts the wheelchair user whenever necessary. The alert method has been defined as a result of a utility/usability/acceptability study conducted with representative end users. It is based on a tactile-visual feedback (via a watch or a smartphone for example): the tactile modality is used to discreetly alarm the person while the visual modality conveys an informative message. In order to evaluate the usability of the TexiCare device, a paraplegic volunteer equipped his wheelchair at home during a six months period. Interestingly, the first results revealed bad habits such as an inadequate posture when watching TV, rare relief maneuvers, and the occurrence of abnormal high pressures. Copyright © 2013 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

Validation of the Andon KD5031 for clinical use and self-measurement according to the European Society of Hypertension International Protocol.

PubMed

Wu, Ning; Zhang, Xuezhong; Wang, Wen; Zhang, Hongye

2016-10-01

This study aimed to evaluate the accuracy of the automated oscillometric upper arm blood pressure (BP) monitor Andon KD5031 for home BP monitoring according to the European Society of Hypertension International Protocol revision 2010. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were sequentially measured in 33 participants using the standard mercury sphygmomanometer and the Andon KD5031 device. Ninety-nine pairs of comparisons were obtained from 33 participants for analysis. The KD5031 device achieved the targets in part 1 of the validation study. The number of absolute differences between the device and the observers within a range of 5, 10, and 15 mmHg was 66/99, 93/99, and 98/99, respectively, for SBP and 72/99, 94/99, and 99/99, respectively, for DBP. The device also achieved the targets in part 2 of the validation study. Twenty-six participants for both SBP and DBP had at least two of the three device-observer differences within 5 mmHg (required ≥24). The number of participants without a device-observer difference within 5 mmHg was one for SBP and three for DBP (required ≤3). The Andon upper arm BP monitor KD5031 has passed the International Protocol requirements, and it can be recommended for clinical use and self-measurement in adults.

Nonlinear Sound Field by Interdigital Transducers in Water

NASA Astrophysics Data System (ADS)

Maezawa, Miyuki; Kamada, Rui; Kamakura, Tomoo; Matsuda, Kazuhisa

2008-05-01

Nonlinear ultrasound beams in water radiated by a surface acoustic wave (SAW) device are examined experimentally and theoretically. SAWs on an 128° X-cut Y-propagation LiNbO3 substrate are excited by 50 pairs of interdigital transducers (IDTs). The device with a 2 ×10 mm2 rectangular aperture and a center frequency of 20 MHz radiate two ultrasound beams in the direction of the Rayleigh angle determined by the propagation speed of the SAW on the device and of the longitudinal wave in water. The Rayleigh angle becomes 22° in the present experimental situation. The fundamental and second harmonic sound pressures are respectively measured along and across the beam using a miniature hydrophone whose active element 0.4 mm in diameter and whose frequency response is calibrated up to 40 MHz. The Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation is utilized to theoretically predict sound pressure amplitudes. The theoretical predictions of both the fundamental and second harmonic pressures agree well with the measured sound pressures.

Dynamic diamond anvil cell (dDAC): A novel device for studying the dynamic-pressure properties of materials

NASA Astrophysics Data System (ADS)

Evans, William J.; Yoo, Choong-Shik; Lee, Geun Woo; Cynn, Hyunchae; Lipp, Magnus J.; Visbeck, Ken

2007-07-01

We have developed a unique device, a dynamic diamond anvil cell (dDAC), which repetitively applies a time-dependent load/pressure profile to a sample. This capability allows studies of the kinetics of phase transitions and metastable phases at compression (strain) rates of up to 500GPa/s (˜0.16s-1 for a metal). Our approach adapts electromechanical piezoelectric actuators to a conventional diamond anvil cell design, which enables precise specification and control of a time-dependent applied load/pressure. Existing DAC instrumentation and experimental techniques are easily adapted to the dDAC to measure the properties of a sample under the varying load/pressure conditions. This capability addresses the sparsely studied regime of dynamic phenomena between static research (diamond anvil cells and large volume presses) and dynamic shock-driven experiments (gas guns, explosive, and laser shock). We present an overview of a variety of experimental measurements that can be made with this device.

Validation of the ROSSMAX blood pressure measuring monitor according to the European Society of Hypertension International Protocol for Validation of Blood Pressure Measuring Devices in Adults.

PubMed

O'Brien, Eoin; Atkins, Neil; Murphy, Anne; Lyons, Simon

2003-12-01

It is now accepted that blood pressure measuring devices should be subjected to an independent evaluation of their accuracy before they are marketed for clinical use. The results of validation of the ROSSMAX Blood Pressure Measuring Monitor for self-measurement according to the European Society of Hypertension International Protocol for Validation of Blood Pressure Measuring Devices in Adults are presented in this paper. Thirty-three subjects were recruited from among staff and patients at Beaumont Hospital, Dublin, Ireland. The ROSSMAX monitor was connected to the Sphygmocorder, an audiovisual system for validation, which records blood pressure on tape and video for later analysis. Nine sequential same-arm measurements between the device and a standard mercury sphygmomanometer were recorded using the Sphygmocorder. In phase 1, the ROSSMAX monitor produced 21 measurements within 5 mmHg, 31 within 10 mmHg and 38 within 15 mmHg for systolic blood pressure (SBP), and 36 within 5 mmHg, 43 within 10 mmHg and 45 within 15 mmHg for diastolic blood pressure (DBP). The mean differences were -5.6 (10.2) [mean (SD)] mmHg for SBP and -0.5 (4.5) mmHg for DBP. The ROSSMAX monitor failed to meet any of the criteria for SBP but comfortably passed all of the criteria for DBP. In phase 2.1, the ROSSMAX monitor had 51 measurements within 5 mmHg, 73 within 10 mmHg and 86 within 15 mmHg for SBP, and 71 measurements within 5 mmHg, 93 within 10 mmHg and 98 within 15 mmHg for DBP. The mean differences were -4.5. (9.5) mmHg for SBP and -1.8 (5.0) mmHg for DBP. The ROSSMAX monitor failed to meet any of the criteria for SBP but comfortably passed all of the criteria for DBP. In phase 2.2, 16 subjects had at least two of the differences lying within 5 mmHg and 10 subjects had no differences within 5 mmHg for SBP; 26 subjects had at least two of the differences falling within 5 mmHg and three subjects no differences within 5 mmHg for DBP. The ROSSMAX monitor failed to meet the criteria for SBP but passed the criteria for DBP. The ROSSMAX monitor cannot be recommended for clinical use in an adult population because it records SBP inaccurately.

Determining phase diagrams of gas-liquid systems using a microfluidic PVT.

PubMed

Mostowfi, Farshid; Molla, Shahnawaz; Tabeling, Patrick

2012-11-07

A novel microfluidic device designed for analyzing phase diagrams of gas-liquid systems (PVT or pressure-volume-temperature measurements) is described. The method mimics the phase transition of a reservoir fluid as it travels through the wellbore from the formation to the surface. The device consists of a long serpentine microchannel etched in a silicon substrate. The local pressure inside the channel is measured using membrane-based optical pressure sensors positioned along the channel. Geometrical restrictions are placed along the microchannel in order to nucleate bubbles when nucleation conditions are met, thus preventing the development of a supersaturation state in the channel. We point out that a local equilibrium state between gas and liquid phases is achieved, which implies that equilibrium properties can be directly measured on the chip. We analyze different mixtures of hydrocarbon systems and, consistently with the preceding analysis, obtain excellent agreement between our technique and conventional measurements. From a practical viewpoint (important for the relevance of the technology), we observe that the measurement time of thermodynamic properties of gas-liquid systems is reduced from hours to minutes with the present device without compromising the measurement accuracy.

All solution-processed micro-structured flexible electrodes for low-cost light-emitting pressure sensors fabrication.

PubMed

Shimotsu, Rie; Takumi, Takahiro; Vohra, Varun

2017-07-31

Recent studies have demonstrated the advantage of developing pressure-sensitive devices with light-emitting properties for direct visualization of pressure distribution, potential application to next generation touch panels and human-machine interfaces. To ensure that this technology is available to everyone, its production cost should be kept as low as possible. Here, simple device concepts, namely, pressure sensitive flexible hybrid electrodes and OLED architecture, are used to produce low-cost resistive or light-emitting pressure sensors. Additionally, integrating solution-processed self-assembled micro-structures into the flexible hybrid electrodes composed of an elastomer and conductive materials results in enhanced device performances either in terms of pressure or spatial distribution sensitivity. For instance, based on the pressure applied, the measured values for the resistances of pressure sensors range from a few MΩ down to 500 Ω. On the other hand, unlike their evaporated equivalents, the combination of solution-processed flexible electrodes with an inverted OLED architectures display bright green emission when a pressure over 200 kPa is applied. At a bias of 3 V, their luminance can be tuned by applying a higher pressure of 500 kPa. Consequently, features such as fingernails and fingertips can be clearly distinguished from one another in these long-lasting low-cost devices.

Thin film devices used as oxygen partial pressure sensors

NASA Technical Reports Server (NTRS)

Canady, K. S.; Wortman, J. J.

1970-01-01

Electrical conductivity of zinc oxide films to be used in an oxygen partial pressure sensor is measured as a function of temperature, oxygen partial pressure, and other atmospheric constituents. Time response following partial pressure changes is studied as a function of temperature and environmental changes.

Development of an Inlet Pressure Sensor for Control in a Left Ventricular Assist Device

PubMed Central

Fritz, Bryan; Cysyk, Joshua; Newswanger, Ray; Weiss, William; Rosenberg, Gerson

2010-01-01

A Tesla type continuous flow left ventricular assist device (VAD) has been designed by Penn State and Advanced Bionics, Inc. (ABI). When a continuous flow device is employed, care must be taken to limit low pressures in the ventricle that can produce an obstruction to the inlet cannula or trigger arrhythmias. Design of an inexpensive, semi-conductor strain gage inlet pressure sensor to detect suction has been completed. The research and design analysis included finite element modeling of the sensing region. Sensitivity, step-response, temperature dependence and hysteresis tests have been performed on prototype units. All sensors were able to withstand the maximum expected strain of 82 μin/in at 500 mmHg internal pressure. Average sensitivity was 0.52 ±0.24 μV/mmHg with 0.5 V excitation (n=5 units). Step response time for a 0 to 90 mmHg step change averaged 22 milliseconds. Hysteresis was measured by applying and holding 75mmHg internal pressure for 4 hours, followed by a zero pressure measurement, and ranged from -15 mmHg to 4.1 mmHg (n=3 units). Offset drift varied between 180 and -140 mmHg over a four week period. (n=2 units). Span temperature sensitivity ranged from 18 to -21 μV/°C (n=5 units). Gain temperature sensitivity ranged from -7.4 to 4.9 μV/°C (n=5 units). With the inherent drift, it is currently not possible to use the transducer to measure actual pressures, but it can easily be used to measure pressure changes throughout the cardiac cycle. This signal can then be used in the control system to avoid ventricular suction events. PMID:20335797

Apparatus for passive removal of subsurface contaminants and mass flow measurement

DOEpatents

Jackson, Dennis G [Augusta, GA; Rossabi, Joseph [Aiken, SC; Riha, Brian D [Augusta, GA

2003-07-15

A system for improving the Baroball valve and a method for retrofitting an existing Baroball valve. This invention improves upon the Baroball valve by reshaping the interior chamber of the valve to form a flow meter measuring chamber. The Baroball valve sealing mechanism acts as a rotameter bob for determining mass flow rate through the Baroball valve. A method for retrofitting a Baroball valve includes providing static pressure ports and connecting a measuring device, to these ports, for measuring the pressure differential between the Baroball chamber and the well. A standard curve of nominal device measurements allows the mass flow rate to be determined through the retrofitted Baroball valve.

Apparatus for passive removal of subsurface contaminants and volume flow measurement

DOEpatents

Jackson, Dennis G.; Rossabi, Joseph; Riha, Brian D.

2002-01-01

A system for improving the Baroball valve and a method for retrofitting an existing Baroball valve. This invention improves upon the Baroball valve by reshaping the interior chamber of the valve to form a flow meter measuring chamber. The Baroball valve sealing mechanism acts as a rotameter bob for determining volume flow rate through the Baroball valve. A method for retrofitting a Baroball valve includes providing static pressure ports and connecting a measuring device, to these ports, for measuring the pressure differential between the Baroball chamber and the well. A standard curve of nominal device measurements allows the volume flow rate to be determined through the retrofitted Baroball valve.

Validation of the Somnotouch-NIBP noninvasive continuous blood pressure monitor according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Bilo, Grzegorz; Zorzi, Cristina; Ochoa Munera, Juan E; Torlasco, Camilla; Giuli, Valentina; Parati, Gianfranco

2015-10-01

The present study aimed to evaluate the accuracy of the Somnotouch-NIBP noninvasive continuous blood pressure monitor according to the European Society of Hypertension International Protocol revision 2010. Systolic and diastolic blood pressures were sequentially measured in 33 adults (11 women, mean age 63.5±11.9 years) using a mercury sphygmomanometer (two observers) and the Somnotouch-NIBP device (one supervisor). A total of 99 pairs of comparisons were obtained from 33 participants for judgments in two parts with three grading phases. All the validation requirements were fulfilled. The Somnotouch-NIBP device fulfilled the requirements of the part 1 of the validation study. The number of absolute differences between device and observers within 5, 10, and 15 mmHg was 75/99, 90/99, and 96/99, respectively, for systolic blood pressure and 90/99, 99/99, and 99/99, respectively, for diastolic blood pressure. The device also fulfilled the criteria in part 2 of the validation study. Twenty-seven and 31 participants had at least two of the three device-observers differences less than or equal to 5 mmHg for systolic and diastolic blood pressure, respectively. All three device-observer differences were greater than 5 mmHg in two participants for systolic and in one participant for diastolic blood pressure. The Somnotouch-NIBP noninvasive continuous blood pressure monitor has passed the requirements of the International Protocol revision 2010, and hence can be recommended for blood pressure monitoring in adults, at least under conditions corresponding to those investigated in our study.

Measuring Intracranial Pressure And Volume Noninvasively

NASA Technical Reports Server (NTRS)

Cantrell, John H.; Yost, William T.

1994-01-01

Ultrasonic technique eliminates need to drill into brain cavity. Intracranial dynamics instrument probes cranium ultrasonically to obtain data for determination of intracranial pressure (ICP) and pressure-volume index (PVI). Instrument determines sensitivity of skull to changes in pressure and by use of mechanical device to exert external calibrated pressure on skull. By monitoring volume of blood flowing into jugular vein, one determines change of volume of blood in cranial system. By measuring response of skull to increasing pressure (where pressure increased by tilting patient known amount) and by using cranial blood pressure, one determines intial pressure in cerebrospinal fluid. Once PVI determined, ICP determined.

Can validated wrist devices with position sensors replace arm devices for self-home blood pressure monitoring? A randomized crossover trial using ambulatory monitoring as reference.

PubMed

Stergiou, George S; Christodoulakis, George R; Nasothimiou, Efthimia G; Giovas, Periklis P; Kalogeropoulos, Petros G

2008-07-01

Electronic devices that measure blood pressure (BP) at the arm level are regarded as more accurate than wrist devices and are preferred for home BP (HBP) monitoring. Recently, wrist devices with position sensors have been successfully validated using established protocols. This study assessed whether HBP values measured with validated wrist devices are sufficiently reliable to be used for making patient-related decisions in clinical practice. This randomized crossover study compared HBP measurements taken using validated wrist devices (wrist-HBP, Omron R7 with position sensor) with those taken using arm devices (arm-HBP, Omron 705IT), and also with measurements of awake ambulatory BP (ABP, SpaceLabs), in 79 subjects (36 men and 43 women) with hypertension. The mean age of the study population was 56.7 +/- 11.8 years, and 33 of the subjects were not under treatment for hypertension. The average arm-HBP was higher than the average wrist-HBP (mean difference, systolic 5.2 +/- 9.1 mm Hg, P < 0.001, and diastolic 2.2 +/- 6.7, P < 0.01). Twenty-seven subjects (34%) had a > or =10 mm Hg difference between systolic wrist-HBP and arm-HBP and twelve subjects (15%) showed similar levels of disparity in diastolic HBP readings. Strong correlations were found between arm-HBP and wrist-HBP (r 0.74/0.74, systolic/diastolic, P < 0.0001). However, ABP was more strongly correlated with arm-HBP (r 0.73/0.76) than with wrist-HBP (0.55/0.69). The wrist-arm HBP difference was associated with systolic ABP (r 0.34) and pulse pressure (r 0.29), but not with diastolic ABP, sex, age, arm circumference, and wrist circumference. There might be important differences in HBP measured using validated wrist devices with position sensor vs. arm devices, and these could impact decisions relating to the patient in clinical practice. Measurements taken using arm devices are more closely related to ABP values than those recorded by wrist devices. More research is needed before recommending the widespread use of wrist monitors in clinical practice. American Journal of Hypertension doi:10.1038/ajh.2008.176American Journal of Hypertension (2008); 21, 7, 753-758. doi:10.1038/ajh.2008.176.

A comparison study of brachial blood pressure recorded with Spacelabs 90217A and Mobil-O-Graph NG devices under static and ambulatory conditions.

PubMed

Sarafidis, P A; Lazaridis, A A; Imprialos, K P; Georgianos, P I; Avranas, K A; Protogerou, A D; Doumas, M N; Athyros, V G; Karagiannis, A I

2016-12-01

Ambulatory blood pressure monitoring is an important tool in hypertension diagnosis and management. Although several ambulatory devices exist, comparative studies are scarce. This study aimed to compare for the first time brachial blood pressure levels of Spacelabs 90217A and Mobil-O-Graph NG, under static and ambulatory conditions. We examined 40 healthy individuals under static (study A) and ambulatory (study B) conditions. In study A, participants were randomized into two groups that included blood pressure measurements with mercury sphygmomanometer, Spacelabs and Mobil-O-Graph devices with reverse order of recordings. In study B, simultaneous 6-h recordings with both devices were performed with participants randomized in two sequences of device positioning with arm reversal at 3 h. Finally, all the participants filled in a questionnaire rating their overall preference for a device. In study A, brachial systolic blood pressure (117.2±10.3 vs 117.1±9.8 mm Hg, P=0.943) and diastolic blood pressure (73.3±9.4 mm Hg vs 74.1±9.4 mm Hg, P=0.611) did not differ between Spacelabs and Mobil-O-Graph or vs sphygmomanometer (117.8±11.1 mm Hg, P=0.791 vs Spacelabs, P=0.753 vs Mobil-O-Graph). Similarly, no differences were found in ambulatory systolic blood pressure (117.9±11.4 vs 118.3±11.0 mm Hg, P=0.864), diastolic blood pressure (73.7±7.4 vs 74.7±8.0 mm Hg, P=0.571), mean blood pressure and heart rate between Spacelabs and Mobil-O-Graph. Correlation analyses and Bland-Altman plots showed agreement between the monitors. Overall, the participants showed a preference for the Mobil-O-Graph. Spacelabs 90217A and Mobil-O-Graph NG provide practically identical measurements during the static and ambulatory conditions in healthy individuals and can be rather used interchangeably in clinical practice.

Automatic algorithm for monitoring systolic pressure variation and difference in pulse pressure.

PubMed

Pestel, Gunther; Fukui, Kimiko; Hartwich, Volker; Schumacher, Peter M; Vogt, Andreas; Hiltebrand, Luzius B; Kurz, Andrea; Fujita, Yoshihisa; Inderbitzin, Daniel; Leibundgut, Daniel

2009-06-01

Difference in pulse pressure (dPP) reliably predicts fluid responsiveness in patients. We have developed a respiratory variation (RV) monitoring device (RV monitor), which continuously records both airway pressure and arterial blood pressure (ABP). We compared the RV monitor measurements with manual dPP measurements. ABP and airway pressure (PAW) from 24 patients were recorded. Data were fed to the RV monitor to calculate dPP and systolic pressure variation in two different ways: (a) considering both ABP and PAW (RV algorithm) and (b) ABP only (RV(slim) algorithm). Additionally, ABP and PAW were recorded intraoperatively in 10-min intervals for later calculation of dPP by manual assessment. Interobserver variability was determined. Manual dPP assessments were used for comparison with automated measurements. To estimate the importance of the PAW signal, RV(slim) measurements were compared with RV measurements. For the 24 patients, 174 measurements (6-10 per patient) were recorded. Six observers assessed dPP manually in the first 8 patients (10-min interval, 53 measurements); no interobserver variability occurred using a computer-assisted method. Bland-Altman analysis showed acceptable bias and limits of agreement of the 2 automated methods compared with the manual method (RV: -0.33% +/- 8.72% and RV(slim): -1.74% +/- 7.97%). The difference between RV measurements and RV(slim) measurements is small (bias -1.05%, limits of agreement 5.67%). Measurements of the automated device are comparable with measurements obtained by human observers, who use a computer-assisted method. The importance of the PAW signal is questionable.

Use of home blood-pressure monitoring in the detection, treatment and surveillance of hypertension.

PubMed

Manning, Gillian; Donnelly, Richard

2005-11-01

Use of home blood-pressure monitoring is increasing but the technique and the equipment have limitations. We provide an overview of recent evidence in this rapidly evolving field. Home blood-pressure monitoring is an acceptable method for screening patients for hypertension. There is increasing evidence supporting the predictive power of home blood pressure for stroke risk even in the general population. The identification of white-coat and masked hypertension remains an important role for home blood-pressure monitoring. Unvalidated equipment and poor patient technique are major concerns. The purchase of devices needs to be linked to a simple patient-education programme, which is perhaps an opportunity for collaboration between healthcare providers and commercial companies. Devices that store the blood-pressure measurements in the memory are preferred to ensure accuracy of reporting. Data-transmission systems providing automatic storage, transmission and reporting of blood pressure, direct involvement of the patient and potentially a reduced number of hospital/general practitioner visits, offer significant advantages. To reduce patient anxiety, overuse of home blood-pressure monitoring should be avoided but there is the potential for self-modification of treatment, subject to certain safeguards. Self-monitoring of blood pressure is developing rapidly, linked to increasing awareness of the impact of reducing high blood pressure on public health and the marketing/advertising strategies used to sell automatic devices. Home blood-pressure monitoring has a role in the detection and management of blood pressure, but not at the expense of careful blood-pressure measurement in the office and adherence to national guidelines.

Surface electromyography and plantar pressure changes with novel gait training device in participants with chronic ankle instability.

PubMed

Feger, Mark A; Hertel, Jay

2016-08-01

Rehabilitation is ineffective at restoring normal gait in chronic ankle instability patients. Our purpose was to determine if a novel gait-training device could decrease plantar pressure on the lateral column of the foot in chronic ankle instability patients. Ten chronic ankle instability patients completed 30s trials of baseline and gait-training walking at a self-selected pace while in-shoe plantar pressure and surface electromyography were recorded from their anterior tibialis, peroneus longus, medial gastrocnemius, and gluteus medius. The gait-training device applied a medially-directed force to the lower leg via elastic bands during the entire gait cycle. Plantar pressure measures of the entire foot and 9 specific regions of the foot as well as surface electromyography root mean square areas were compared between the baseline and gait-training conditions using paired t-tests with a priori level of significance of p≤0.05. The gait-training device decreased pressure time integrals and peak pressures in the lateral midfoot (p=0.003 and p=0.003) and lateral forefoot (p=0.023 and p=0.005), and increased pressure time integrals and peak pressures for the total foot (p=0.030 and p=0.017) and hallux (p=0.005 and p=0.002). The center of pressure was shifted medially during the entire stance phase (p<0.003 for all comparisons) due to increased peroneus longus activity prior to (p=0.002) and following initial contact (p=0.002). The gait-training device decreased pressure on the lateral column of the foot and increased peroneus longus muscle activity. Future research should analyze the efficacy of the gait-training device during gait retraining for chronic ankle instability. Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel cuffless device for self-measurement of blood pressure: concept, performance and clinical validation.

PubMed

Boubouchairopoulou, N; Kollias, A; Chiu, B; Chen, B; Lagou, S; Anestis, P; Stergiou, G S

2017-07-01

A pocket-size cuffless electronic device for self-measurement of blood pressure (BP) has been developed (Freescan, Maisense Inc., Zhubei, Taiwan). The device estimates BP within 10 s using three embedded electrodes and one force sensor that is applied over the radial pulse to evaluate the pulse wave. Before use, basic anthropometric characteristics are recorded on the device, and individualized initial calibration is required based on a standard BP measurement performed using an upper-arm BP monitor. The device performance in providing valid BP readings was evaluated in 313 normotensive and hypertensive adults in three study phases during which the device sensor was upgraded. A formal validation study of a prototype device against mercury sphygmomanometer was performed according to the American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization (ANSI/AAMI/ISO) 2013 protocol. The test device succeeded in obtaining a valid BP measurement (three successful readings within up to five attempts) in 55-72% of the participants, which reached 87% with device sensor upgrade. For the validation study, 125 adults were recruited and 85 met the protocol requirements for inclusion. The mean device-observers BP difference was 3.2±6.7 (s.d.) mm Hg for systolic and 2.6±4.6 mm Hg for diastolic BP (criterion 1). The estimated s.d. (inter-subject variability) were 5.83 and 4.17 mm Hg respectively (criterion 2). These data suggest that this prototype cuffless BP monitor provides valid self-measurements in the vast majority of adults, and satisfies the BP measurement accuracy criteria of the ANSI/AAMI/ISO 2013 validation protocol.

[Validation of the Omron HEM-650 wrist blood pressure device using the British Hypertension Society protocol in emergency patients in Hong Kong].

PubMed

Hung, Kevin KC; Lai, W Y; Cocks, Robert A; Rainer, Timothy H; Graham, Colin A

2015-10-01

Automated wrist cuff blood pressure (BP) devices are more compact and easier to use, particularly when access to the upper arm is restricted, for example in emergencies. We tested the Omron HEM-650 wrist device using the validation criteria of the British Hypertension Society (BHS) protocol in a major emergency department (ED) in Hong Kong. 85 patients had three measurements each by both the Omron HEM-650 wrist device and the mercury sphygmomanometer. The conventional automated BP with arm cuff was also measured using an oscillometric (Colin BP-88S NXT) device for comparison. The Omron HEM-650 achieved a grade B for both systolic and diastolic BP and demonstrated acceptable accuracy and reliability in Chinese patients in the emergency setting. The Omron HEM 650 wrist device can be recommended for use in adult emergency patients. Further research is warranted for its use in pregnant women and critically ill patients.

Association of HeartMate II left ventricular assist device flow estimate with thermodilution cardiac output.

PubMed

Hasin, Tal; Huebner, Marianne; Li, Zhuo; Brown, Daniel; Stulak, John M; Boilson, Barry A; Joyce, Lyle; Pereira, Naveen L; Kushwaha, Sudhir S; Park, Soon J

2014-01-01

Cardiac output (CO) assessment is important in treating patients with heart failure. Durable left ventricular assist devices (LVADs) provide essentially all CO. In currently used LVADs, estimated device flow is generated by a computerized algorithm. However, LVAD flow estimate may be inaccurate in tracking true CO. We correlated LVAD (HeartMate II) flow with thermodilution CO during postoperative care (day 2-10 after implant) in 81 patients (5,616 paired measurements). Left ventricular assist device flow and CO correlated with a low correlation coefficient (r = 0.42). Left ventricular assist device readings were lower than CO measurements by approximately 0.36 L/min, trending for larger difference with higher values. Left ventricular assist device flow measurements showed less temporal variability compared with CO. Grouping for simultaneous measured blood pressure (BP < 60, 60-70, 70-80, 80-90, and ≥90), the correlation of CO with LVAD flow differed (R = 0.42, 0.67, 0.48, 0.32, 0.32, respectively). Indicating better correlation when mean blood pressure is 60 to 70 mm Hg. Left ventricular assist device flow generally trends with measured CO, but large variability exists, hence flow measures should not be assumed to equal with CO. Clinicians should take into account variables such as high CO, BP, and opening of the aortic valve when interpreting LVAD flow readout. Direct flow sensors incorporated in the LVAD system may allow for better estimation.

46 CFR 160.151-45 - Equipment required for servicing facilities.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., or other pressure-measurement device or pressure gauge of equivalent accuracy and sensitivity; (j) Thermometer; (k) Barometer, aneroid or mercury; (l) Calibrated torque-wrench for assembling the inflation...

46 CFR 160.151-45 - Equipment required for servicing facilities.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., or other pressure-measurement device or pressure gauge of equivalent accuracy and sensitivity; (j) Thermometer; (k) Barometer, aneroid or mercury; (l) Calibrated torque-wrench for assembling the inflation...

Beat-to-Beat Blood Pressure Monitor

NASA Technical Reports Server (NTRS)

Lee, Yong Jin

2012-01-01

This device provides non-invasive beat-to-beat blood pressure measurements and can be worn over the upper arm for prolonged durations. Phase and waveform analyses are performed on filtered proximal and distal photoplethysmographic (PPG) waveforms obtained from the brachial artery. The phase analysis is used primarily for the computation of the mean arterial pressure, while the waveform analysis is used primarily to obtain the pulse pressure. Real-time compliance estimate is used to refine both the mean arterial and pulse pressures to provide the beat-to-beat blood pressure measurement. This wearable physiological monitor can be used to continuously observe the beat-to-beat blood pressure (B3P). It can be used to monitor the effect of prolonged exposures to reduced gravitational environments and the effectiveness of various countermeasures. A number of researchers have used pulse wave velocity (PWV) of blood in the arteries to infer the beat-to-beat blood pressure. There has been documentation of relative success, but a device that is able to provide the required accuracy and repeatability has not yet been developed. It has been demonstrated that an accurate and repeatable blood pressure measurement can be obtained by measuring the phase change (e.g., phase velocity), amplitude change, and distortion of the PPG waveforms along the brachial artery. The approach is based on comparing the full PPG waveform between two points along the artery rather than measuring the time-of-flight. Minimizing the measurement separation and confining the measurement area to a single, well-defined artery allows the waveform to retain the general shape between the two measurement points. This allows signal processing of waveforms to determine the phase and amplitude changes.

[An implantable micro-device using wireless power transmission for measuring aortic aneurysm sac pressure].

PubMed

Guo, Xudong; Ge, Bin; Wang, Wenxing

2013-08-01

In order to detect endoleaks after endovascular aneurysm repair (EVAR), we developed an implantable micro-device based on wireless power transmission to measure aortic aneurysm sac pressure. The implantable micro-device is composed of a miniature wireless pressure sensor, an energy transmitting coil, a data recorder and a data processing platform. Power transmission without interconnecting wires is performed by a transmitting coil and a receiving coil. The coupling efficiency of wireless power transmission depends on the coupling coefficient between the transmitting coil and the receiving coil. With theoretical analysis and experimental study, we optimized the geometry of the receiving coil to increase the coupling coefficient. In order to keep efficiency balance and satisfy the maximizing conditions, we designed a closed loop power transmission circuit, including a receiving voltage feedback module based on wireless communication. The closed loop improved the stability and reliability of transmission energy. The prototype of the micro-device has been developed and the experiment has been performed. The experiments showed that the micro-device was feasible and valid. For normal operation, the distance between the transmitting coil and the receiving coil is smaller than 8cm. Besides, the distance between the micro-device and the data recorder is within 50cm.

Modifications to the nozzle test chamber to extend nozzle static-test capability

NASA Technical Reports Server (NTRS)

Keyes, J. W.

1985-01-01

The nozzle test chamber was modified to provide a high-pressure-ratio nozzle static-test capability. Experiments were conducted to determine the range of the ratio of nozzle total pressure to chamber pressure and to make direct nozzle thrust measurements using a three-component strain-gage force balance. Pressure ratios from 3 to 285 were measured with several axisymmetric nozzles at a nozzle total pressure of 15 to 190 psia. Devices for measuring system mass flow were calibrated using standard axisymmetric convergent choked nozzles. System mass-flow rates up to 10 lbm/sec are measured. The measured thrust results of these nozzles are in good agreement with one-dimensional theoretical predictions for convergent nozzles.

Suprapubic track pressure and force--deformation measurements in a (live) human subject and in animal models post-mortem.

PubMed

Coveney, V A; Gepi-Attee, S; Gröver, D; Painter, D

2001-01-01

Tests have been performed on animal models shortly post-mortem and on a healthy human subject in order to obtain estimates of the forces which act on suprapubic urinary catheters and similar devices and to develop an abdominal wall simulator. Such data and test methods are required for the systematic design of suprapubic devices because of the dual need to maintain the functionality of devices and to avoid excessive pressure on soft body tissue which could lead to ischaemia and in turn necrosis. In the post-mortem animal models, electrical excitation was applied to the abdominal wall in order to stimulate muscle activity. Two types of transducers were used: a soft membrane transducer (SMT) for pressure measurement and novel instrumented 'tongs' to determine indentation stiffness characteristics in the suprapubic track or artificial pathway created for a device. The SMT has been extensively used in the urethras and bladders of human subjects while the tongs were built specifically for these tests. Only the well-established SMT was used with the human subject; a peak pressure of 22 kPa was obtained. In the animal models the pressure profile given by the SMT had a peak whose position corresponded well with the estimated location of the rectus muscle measured on the fixed tissue section. The peak value was 5.5 kPa, comparable with values likely to cause necrosis if maintained for more than 1 day. Remarkably consistent indentation stiffness values were obtained with the instrumented tongs; all values were close to 0.45 N/mm (33 kPa/mm).

Proposal of a method for the evaluation of inaccuracy of home sphygmomanometers.

PubMed

Akpolat, Tekin

2009-10-01

There is no formal protocol for evaluating the individual accuracy of home sphygmomanometers. The aims of this study were to propose a method for achieving accuracy in automated home sphygmomanometers and to test the applicability of the defined method. The purposes of this method were to avoid major inaccuracies and to estimate the optimal circumstance for individual accuracy. The method has three stages and sequential measurement of blood pressure is used. The tested devices were categorized into four groups: accurate, acceptable, inaccurate and very inaccurate (major inaccuracy). The defined method takes approximately 10 min (excluding relaxation time) and was tested on three different occasions. The application of the method has shown that inaccuracy is a common problem among non-tested devices, that validated devices are superior to those that are non-validated or whose validation status is unknown, that major inaccuracy is common, especially in non-tested devices and that validation does not guarantee individual accuracy. A protocol addressing the accuracy of a particular sphygmomanometer in an individual patient is required, and a practical method has been suggested to achieve this. This method can be modified, but the main idea and approach should be preserved unless a better method is proposed. The purchase of validated devices and evaluation of accuracy for the purchased device in an individual patient will improve the monitoring of self-measurement of blood pressure at home. This study addresses device inaccuracy, but errors related to the patient, observer or blood pressure measurement technique should not be underestimated, and strict adherence to the manufacturer's instructions is essential.

21 CFR 870.2850 - Extravascular blood pressure transducer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... used to measure blood pressure by changes in the mechanical or electrical properties of the device. The... electrical signal related to the electrical or mechanical changes produced in the transducer. (b...

Fast pressure-sensor system

NASA Technical Reports Server (NTRS)

Gross, C.

1976-01-01

Miniature silicon-diaphragm sensors and signal multiplexer are mounted to ganged zero-operate-calibrate pressure selector switches. Device allows in-situ calibration, can be computer controlled, and measures at approximately 10,000 readings per second.

Pneumatic bracing and total contact casting have equivocal effects on plantar pressure relief.

PubMed

Hartsell, H D; Fellner, C; Saltzman, C L

2001-06-01

The purpose was to examine and compare plantar pressures produced in healthy subjects while wearing a running shoe (RS), total contact cast (TCC) and 'customized' pneumatic pre-fabricated walking brace (PWB). A repeated measures design was used to compare the plantar pressures recorded for three footwear types (RS, TCC, PWB) in two body regions (forefoot, heel). Nine healthy subjects walked at a self-selected walking pace on a motorized treadmill while wearing the RS, TCC and PWB (ordered randomization). Following a five-minute acclimatization period on the treadmill with each footwear device, plantar pressures were recorded from 84 constant gait speed and step length steps using the Pedar system of in-shoe array of capacitive sensors embedded in an insert. Mean spatially averaged peak plantar pressures were recorded for the metatarsal heads and heel region for each footwear device worn by each subject. A two-way analysis of variance with repeated measures and post-hoc Tukey tests analysed the data with a significance level of p=.05. The main effects of footwear (p=.005) and body region (p=.000), and interaction effect (body region x footwear device) (p=.000) were significant. Unloading of the forefoot was 63.72% and 58.77% for the TCC and PWB, respectively, whereas loading under the heel was increased 37.09% and 34.11% for the same two devices, respectively. Patients who develop neuropathic plantar ulcers in the forefoot region, but not in the heel region, may benefit from a reduction in plantar pressures by using either the TCC or a 'customized' PWB. An alternative footwear device still needs to be found for those patients with heel ulceration.

A randomized comparison of the i-gel with the self-pressurized air-Q intubating laryngeal airway in children.

PubMed

Kim, Min-Soo; Lee, Jae Hoon; Han, Sang Won; Im, Young Jae; Kang, Hyo Jong; Lee, Jeong-Rim

2015-04-01

Supraglottic airway devices with noninflatable cuff have advantages in omitting the cuff pressure monitoring and reducing potential pharyngolaryngeal complications. Typical devices without cuff inflation available in children are the i-gel and the self-pressurized air-Q intubating laryngeal airway (air-Q SP). To date, there is no comparative study between these devices in pediatric patients. The purpose of this randomized study was to compare the i-gel(™) and the self-pressurized air-Q(™) intubating laryngeal airway (air-Q SP) in children undergoing general anesthesia. Eighty children, 1-108 months of age, 7-30 kg of weight, and scheduled for elective surgery in which supraglottic airway devices would be suitable for airway management, were randomly assigned to either the i-gel or the air-Q SP. Oropharyngeal leak pressure and fiberoptic view were assessed three times as follows: after insertion and fixation of the device, 10 min after initial assessment, and after completion of surgery. We also assessed insertion parameters and complications. Insertion of the i-gel was regarded as significantly easier compared to the air-Q SP (P = 0.04). Compared to the air-Q SP group, the i-gel group had significantly higher oropharyngeal leak pressures at all measurement points and significantly lower frequencies of gastric insufflation at 10 min after initial assessment and completion of surgery. The air-Q SP group had better fiberoptic views than the i-gel group at all measurement points. Our results showed that the i-gel had easier insertion and better sealing function, and the air-Q SP provided improved fiberoptic views in children requiring general anesthesia. © 2015 John Wiley & Sons Ltd.

Development of Skylab medical equipment and flight preparations

NASA Technical Reports Server (NTRS)

Johnston, R. S.; Stonesifer, J. C.; Hawkins, W. R.

1975-01-01

The major medical systems in the Skylab orbital workshop are described. They comprise the food system, the waste management system, operational bioinstrumentation, personal hygiene, gas sampling, an inflight medical support system, and a cardiovascular counterpressure garment. Life sciences experiments carried out aboard Skylab are also reviewed; these include an ergometer and metabolic analyzer, a lower-body negative pressure device, an electrode harness and body temperature probe, a blood pressure cuff, a leg volume measuring band, sleep studies, a body-mass measuring device, a rotating litter chair, a blood sample processor, and small-mass measuring apparatus. All performance requirements were met with the equipment, and no failures were encountered.

Realize multiple hermetic chamber pressures for system-on-chip process by using the capping wafer with diverse cavity depths

NASA Astrophysics Data System (ADS)

Cheng, Shyh-Wei; Weng, Jui-Chun; Liang, Kai-Chih; Sun, Yi-Chiang; Fang, Weileun

2018-04-01

Many mechanical and thermal characteristics, for example the air damping, of suspended micromachined structures are sensitive to the ambient pressure. Thus, micromachined devices such as the gyroscope and accelerometer have different ambient pressure requirements. Commercially available process platforms could be used to fabricate and integrate devices of various functions to reduce the chip size. However, it remains a challenge to offer different ambient pressures for micromachined devices after sealing them by wafer level capping (WLC). This study exploits the outgassing characteristics of the CMOS chip to fabricate chambers of various pressures after the WLC of the Si-above-CMOS (TSMC 0.18 µm 1P5M CMOS process) MEMS process platform. The pressure of the sealed chamber can be modulated by the chamber volume after the outgassing. In other words, the pressure of hermetic sealed chambers can be easily and properly defined by the etching depth of the cavity on an Si capping wafer. In applications, devices sealed with different cavity depths are implemented using the Si-above-CMOS (TSMC 0.18 µm 1P5M CMOS process) MEMS process platform to demonstrate the present approach. Measurements show the feasibility of this simple chamber pressure modulation approach on eight-inch wafers.

Ejector Enhanced Pulsejet Based Pressure Gain Combustors: An Old Idea With a New Twist

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.; Dougherty, Kevin T.

2005-01-01

An experimental investigation of pressure-gain combustion for gas turbine application is described. The test article consists of an off-the-shelf valved pulsejet, and an optimized ejector, both housed within a shroud. The combination forms an effective can combustor across which there is a modest total pressure rise rather than the usual loss found in conventional combustors. Although the concept of using a pulsejet to affect semi-constant volume (i.e., pressure-gain) combustion is not new, that of combining it with a well designed ejector to efficiently mix the bypass flow is. The result is a device which to date has demonstrated an overall pressure rise of approximately 3.5 percent at an overall temperature ratio commensurate with modern gas turbines. This pressure ratio is substantially higher than what has been previously reported in pulsejet-based combustion experiments. Flow non-uniformities in the downstream portion of the device are also shown to be substantially reduced compared to those within the pulsejet itself. The standard deviation of total pressure fluctuations, measured just downstream of the ejector was only 5.0 percent of the mean. This smoothing aspect of the device is critical to turbomachinery applications since turbine performance is, in general, negatively affected by flow non-uniformities and unsteadiness. The experimental rig will be described and details of the performance measurements will be presented. Analyses showing the thermodynamic benefits from this level of pressure-gain performance in a gas turbine will also be assessed for several engine types. Issues regarding practical development of such a device are discussed, as are potential emissions reductions resulting from the rich burning nature of the pulsejet and the rapid mixing (quenching) associated with unsteady ejectors.

Detection of gas leakage

DOEpatents

Thornberg, Steven M; Brown, Jason

2015-02-17

A method of detecting leaks and measuring volumes as well as a device, the Power-free Pump Module (PPM), provides a self-contained leak test and volume measurement apparatus that requires no external sources of electrical power during leak testing or volume measurement. The PPM is a portable, pneumatically-controlled instrument capable of generating a vacuum, calibrating volumes, and performing quantitative leak tests on a closed test system or device, all without the use of alternating current (AC) power. Capabilities include the ability is to provide a modest vacuum (less than 10 Torr) using a venturi pump, perform a pressure rise leak test, measure the gas's absolute pressure, and perform volume measurements. All operations are performed through a simple rotary control valve which controls pneumatically-operated manifold valves.

Cuffless and Continuous Blood Pressure Estimation from the Heart Sound Signals

PubMed Central

Peng, Rong-Chao; Yan, Wen-Rong; Zhang, Ning-Ling; Lin, Wan-Hua; Zhou, Xiao-Lin; Zhang, Yuan-Ting

2015-01-01

Cardiovascular disease, like hypertension, is one of the top killers of human life and early detection of cardiovascular disease is of great importance. However, traditional medical devices are often bulky and expensive, and unsuitable for home healthcare. In this paper, we proposed an easy and inexpensive technique to estimate continuous blood pressure from the heart sound signals acquired by the microphone of a smartphone. A cold-pressor experiment was performed in 32 healthy subjects, with a smartphone to acquire heart sound signals and with a commercial device to measure continuous blood pressure. The Fourier spectrum of the second heart sound and the blood pressure were regressed using a support vector machine, and the accuracy of the regression was evaluated using 10-fold cross-validation. Statistical analysis showed that the mean correlation coefficients between the predicted values from the regression model and the measured values from the commercial device were 0.707, 0.712, and 0.748 for systolic, diastolic, and mean blood pressure, respectively, and that the mean errors were less than 5 mmHg, with standard deviations less than 8 mmHg. These results suggest that this technique is of potential use for cuffless and continuous blood pressure monitoring and it has promising application in home healthcare services. PMID:26393591

Cuffless and Continuous Blood Pressure Estimation from the Heart Sound Signals.

PubMed

Peng, Rong-Chao; Yan, Wen-Rong; Zhang, Ning-Ling; Lin, Wan-Hua; Zhou, Xiao-Lin; Zhang, Yuan-Ting

2015-09-17

Cardiovascular disease, like hypertension, is one of the top killers of human life and early detection of cardiovascular disease is of great importance. However, traditional medical devices are often bulky and expensive, and unsuitable for home healthcare. In this paper, we proposed an easy and inexpensive technique to estimate continuous blood pressure from the heart sound signals acquired by the microphone of a smartphone. A cold-pressor experiment was performed in 32 healthy subjects, with a smartphone to acquire heart sound signals and with a commercial device to measure continuous blood pressure. The Fourier spectrum of the second heart sound and the blood pressure were regressed using a support vector machine, and the accuracy of the regression was evaluated using 10-fold cross-validation. Statistical analysis showed that the mean correlation coefficients between the predicted values from the regression model and the measured values from the commercial device were 0.707, 0.712, and 0.748 for systolic, diastolic, and mean blood pressure, respectively, and that the mean errors were less than 5 mmHg, with standard deviations less than 8 mmHg. These results suggest that this technique is of potential use for cuffless and continuous blood pressure monitoring and it has promising application in home healthcare services.

Validation of the Pangao PG-800B5 for clinical use and self-measurement according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Chen, Wan; Zeng, Zhaolin; Li, Lizhi; Wan, Xiaofen; Wan, Yi

2014-10-01

This study aimed to validate the Pangao PG-800B5 upper arm blood pressure monitor according to the European Society of Hypertension International Protocol revision 2010. A total of 33 participants, 16 men and 17 women, were included in the device evaluation. The protocol requirements were followed precisely. The mean age of the participants was 56.4±21.0 years (range 22-84 years). The mean systolic blood pressure was 143.6±25.5 mmHg (range 98-188 mmHg), the mean diastolic blood pressure was 85.7±17.2 mmHg (range 49-125 mmHg), and the mean arm circumference was 26.1±2.2 cm (range 23-32 cm). On average, the device overestimated the systolic blood pressure by 0.9±4.2 mmHg and diastolic blood pressure by 0.7±4.5 mmHg. The device passed all requirements, fulfilling the standards of the protocol. Therefore, the Pangao PG-800B5 upper arm blood pressure monitor can be recommended for clinical use and self-measurement in an adult population.

Acoustic and Cavitation Fields of Shock Wave Therapy Devices

NASA Astrophysics Data System (ADS)

Chitnis, Parag V.; Cleveland, Robin O.

2006-05-01

Extracorporeal shock wave therapy (ESWT) is considered a viable treatment modality for orthopedic ailments. Despite increasing clinical use, the mechanisms by which ESWT devices generate a therapeutic effect are not yet understood. The mechanistic differences in various devices and their efficacies might be dependent on their acoustic and cavitation outputs. We report acoustic and cavitation measurements of a number of different shock wave therapy devices. Two devices were electrohydraulic: one had a large reflector (HMT Ossatron) and the other was a hand-held source (HMT Evotron); the other device was a pneumatically driven device (EMS Swiss DolorClast Vet). Acoustic measurements were made using a fiber-optic probe hydrophone and a PVDF hydrophone. A dual passive cavitation detection system was used to monitor cavitation activity. Qualitative differences between these devices were also highlighted using a high-speed camera. We found that the Ossatron generated focused shock waves with a peak positive pressure around 40 MPa. The Evotron produced peak positive pressure around 20 MPa, however, its acoustic output appeared to be independent of the power setting of the device. The peak positive pressure from the DolorClast was about 5 MPa without a clear shock front. The DolorClast did not generate a focused acoustic field. Shadowgraph images show that the wave propagating from the DolorClast is planar and not focused in the vicinity of the hand-piece. All three devices produced measurable cavitation with a characteristic time (cavitation inception to bubble collapse) that varied between 95 and 209 μs for the Ossatron, between 59 and 283 μs for the Evotron, and between 195 and 431 μs for the DolorClast. The high-speed camera images show that the cavitation activity for the DolorClast is primarily restricted to the contact surface of the hand-piece. These data indicate that the devices studied here vary in acoustic and cavitation output, which may imply that the mechanisms by which they generate therapeutic effects are different.

Noninvasive arterial blood pressure waveforms in patients with continuous-flow left ventricular assist devices.

PubMed

Martina, Jerson R; Westerhof, Berend E; de Jonge, Nicolaas; van Goudoever, Jeroen; Westers, Paul; Chamuleau, Steven; van Dijk, Diederik; Rodermans, Ben F M; de Mol, Bas A J M; Lahpor, Jaap R

2014-01-01

Arterial blood pressure and echocardiography may provide useful physiological information regarding cardiac support in patients with continuous-flow left ventricular assist devices (cf-LVADs). We investigated the accuracy and characteristics of noninvasive blood pressure during cf-LVAD support. Noninvasive arterial pressure waveforms were recorded with Nexfin (BMEYE, Amsterdam, The Netherlands). First, these measurements were validated simultaneously with invasive arterial pressures in 29 intensive care unit patients. Next, the association between blood pressure responses and measures derived by echocardiography, including left ventricular end-diastolic dimensions (LVEDDs), left ventricular end-systolic dimensions (LVESDs), and left ventricular shortening fraction (LVSF) were determined during pump speed change procedures in 30 outpatients. Noninvasive arterial blood pressure waveforms by the Nexfin monitor slightly underestimated invasive measures during cf-LVAD support. Differences between noninvasive and invasive measures (mean ± SD) of systolic, diastolic, mean, and pulse pressures were -7.6 ± 5.8, -7.0 ± 5.2, -6.9 ± 5.1, and -0.6 ± 4.5 mm Hg, respectively (all <10%). These blood pressure responses did not correlate with LVEDD, LVESD, or LVSF, while LVSF correlated weakly with both pulse pressure (r = 0.24; p = 0.005) and (dP(art)/dt)max (r = 0.25; p = 0.004). The dicrotic notch in the pressure waveform was a better predictor of aortic valve opening (area under the curve [AUC] = 0.87) than pulse pressure (AUC = 0.64) and (dP(art)/dt)max (AUC = 0.61). Patients with partial support rather than full support at 9,000 rpm had a significant change in systolic pressure, pulse pressure, and (dP(art)/dt)max during ramp studies, while echocardiographic measures did not change. Blood pressure measurements by Nexfin were reliable and may thereby act as a compliment to the assessment of the cf-LVAD patient.

Beat-to-Beat Blood Pressure Monitor

NASA Technical Reports Server (NTRS)

Lee, Yong Jin

2012-01-01

This device provides non-invasive beat-to-beat blood pressure measurements and can be worn over the upper arm for prolonged durations. Phase and waveform analyses are performed on filtered proximal and distal photoplethysmographic (PPG) waveforms obtained from the brachial artery. The phase analysis is used primarily for the computation of the mean arterial pressure, while the waveform analysis is used primarily to obtain the pulse pressure. Real-time compliance estimate is used to refine both the mean arterial and pulse pressures to provide the beat-to-beat blood pressure measurement. This wearable physiological monitor can be used to continuously observe the beat-to-beat blood pressure (B3P). It can be used to monitor the effect of prolonged exposures to reduced gravitational environments and the effectiveness of various countermeasures. A number of researchers have used pulse wave velocity (PWV) of blood in the arteries to infer the beat-to-beat blood pressure. There has been documentation of relative success, but a device that is able to provide the required accuracy and repeatability has not yet been developed. It has been demonstrated that an accurate and repeatable blood pressure measurement can be obtained by measuring the phase change (e.g., phase velocity), amplitude change, and distortion of the PPG waveforms along the brachial artery. The approach is based on comparing the full PPG waveform between two points along the artery rather than measuring the time-of-flight. Minimizing the measurement separation and confining the measurement area to a single, well-defined artery allows the waveform to retain the general shape between the two measurement points. This allows signal processing of waveforms to determine the phase and amplitude changes. Photoplethysmography, which measures changes in arterial blood volume, is commonly used to obtain heart rate and blood oxygen saturation. The digitized PPG signals are used as inputs into the beat-to-beat blood pressure measurement algorithm.

An Innovative Flow-Measuring Device: Thermocouple Boundary Layer Rake

NASA Technical Reports Server (NTRS)

Hwang, Danny P.; Fralick, Gustave C.; Martin, Lisa C.; Wrbanek, John D.; Blaha, Charles A.

2001-01-01

An innovative flow-measuring device, a thermocouple boundary layer rake, was developed. The sensor detects the flow by using a thin-film thermocouple (TC) array to measure the temperature difference across a heater strip. The heater and TC arrays are microfabricated on a constant-thickness quartz strut with low heat conductivity. The device can measure the velocity profile well into the boundary layer, about 65 gm from the surface, which is almost four times closer to the surface than has been possible with the previously used total pressure tube.

Validation of four devices: Omron M6 Comfort, Omron HEM-7420, Withings BP-800, and Polygreen KP-7670 for home blood pressure measurement according to the European Society of Hypertension International Protocol

PubMed Central

Topouchian, Jirar; Agnoletti, Davide; Blacher¹, Jacques; Youssef, Ahmed; Chahine, Mirna N; Ibanez, Isabel; Assemani, Nathalie; Asmar, Roland

2014-01-01

Background Four oscillometric devices, including the Omron M6 Comfort, Omron HEM-7420, Withings BP-800, and Polygreen KP-7670, designed for self-blood pressure measurement (SBPM) were evaluated according to the European Society of Hypertension (ESH) International Protocol Revision 2010 in four separate studies. Methods The four devices measure brachial blood pressure (BP) using the oscillometric method. The Withings BP-800 has to be connected to an Apple® iOS device such as an iPhone®, iPad®, or iPod®. The ESH International Protocol Revision 2010 includes a total number of 33 subjects. The difference between observer and device BP values was calculated for each measure. Ninety-nine pairs of BP differences were classified into three categories (≤5 mmHg, ≤10 mmHg, ≤15 mmHg). The protocol procedures were followed precisely in each of the four studies. Results All four tested devices passed the validation process. The mean differences between the device and mercury readings were: −1.8±5.1 mmHg and −0.4±2.8 mmHg for systolic and diastolic BP, respectively, using the Omron M6 Comfort device; 2.5±4.6 mmHg and −1.2±4.3 mmHg for the Omron HEM-7420 device; −0.2±5.0 mmHg and 0.4±4.2 mmHg for the Withings BP-800 device; and 3.0±5.3 mmHg and 0.3±5.2 mmHg for the Polygreen KP-7670 device. Conclusion Omron M6 Comfort, Omron HEM-7420, Withings BP-800, and Polygreen KP-7670 readings differing by less than 5 mmHg, 10 mmHg, and 15 mmHg fulfill the ESH International Protocol Revision 2010 requirements, and therefore are suitable for use by patients for SBPM, if used correctly. PMID:24476688

Automated Versus Manual Blood Pressure Measurement: A Randomized Crossover Trial in the Emergency Department of a Tertiary Care Hospital in Karachi, Pakistan: Are Third World Countries Ready for the Change?

PubMed

Mansoor, Kanaan; Shahnawaz, Saba; Rasool, Mariam; Chaudhry, Huwad; Ahuja, Gul; Shahnawaz, Sara

2016-09-15

Hypertension has proven to be a strong liability with 13.5% of all mortality worldwide being attributed to elevated blood pressures in 2001. An accurate blood pressure measurement lies at the crux of an appropriate diagnosis. Despite the mercury sphygmomanometer being the gold standard, the ongoing deliberation as to whether mercury sphygmomanometers should be replaced with the automated oscillometric devices stems from the risk mercury poses to the environment. This study was performed to check the validity of automated oscillometric blood pressure measurements as compared to the manual blood pressure measurements in Karachi, Pakistan. Blood pressure was recorded in 200 individuals aged 15 and above using both, an automated oscillometric blood pressure device (Dinamap Procare 100) and a manual mercury sphygmomanometer concomitantly. Two nurses were assigned to each patient and the device, arm for taking the reading and nurses were randomly determined. SPSS version 20 was used for analysis. Mean and standard deviation of the systolic and diastolic measurements from each modality were compared to each other and P values of 0.05 or less were considered to be significant. Validation criteria of British Hypertension Society (BHS) and the US Association for the Advancement of Medical Instrumentation (AAMI) were used. Two hundred patients were included. The mean of the difference of systolic was 8.54 ± 9.38 while the mean of the difference of diastolic was 4.21 ± 7.88. Patients were further divided into three groups of different systolic blood pressure <= 120, > 120 to = 150 and > 150, their means were 6.27 ± 8.39 (p-value 0.175), 8.91 ± 8.96 (p-value 0.004) and 10.98 ± 10.49 (p-value 0.001) respectively. In our study 89 patients were previously diagnosed with hypertension; their difference of mean systolic was 9.43 ± 9.89 (p-value 0.000) and difference of mean diastolic was 4.26 ± 7.35 (p-value 0.000). Systolic readings from a previously validated device are not reliable when used in the ER and they show a higher degree of incongruency and inaccuracy when they are used outside validation settings. Also, readings from the right arm tend to be more precise.

T-piece resuscitators: how do they compare?

PubMed

Hinder, Murray; McEwan, Alistair; Drevhammer, Thomas; Donaldson, Snorri; Tracy, Mark Brian

2018-05-04

The T-piece resuscitator (TPR) has seen increased use as a primary resuscitation device with newborns. Traditional TPR design uses a high resistance expiratory valve to produce positive end expiratory pressure (PEEP) or continuous positive airway pressure (CPAP) at resuscitation. A new TPR device that uses a dual flow ratio valve (fluidic flip) to produce PEEP/CPAP is now available (rPAP). We aimed to compare the measured ventilation performance of different TPR devices in a controlled bench test study. Single operator provided positive pressure ventilation to an incremental testlung compliance (Crs) model (0.5-5 mL/cmH 2 O) with five different brands of TPR device (Atom, Neopuff, rPAP, GE Panda warmer and Draeger Resuscitaire). At recommended peak inflation pressure (PIP) 20 cmH 2 O, PEEP of 5 cmH 2 O and rate of 60 inflations per minute. 1864 inflations were analysed. Four of the five devices tested demonstrated inadvertent elevations in mean PEEP (5.5-10.3 cmH 2 O, p<0.001) from set value as Crs was increased, while one device (rPAP) remained at the set value. Measured PIP exceeded the set value in two infant warmer devices (GE and Draeger) with inbuilt TPR at Crs of 0.5 (24.5 and 23.5 cmH 2 O, p<0.001). Significant differences were seen in tidal volumes across devices particularly at higher Crs (p<0.001). Results show important variation in delivered ventilation from set values due to inherent TPR device design characteristics with a range of lung compliances expected at birth. Device-generated inadvertent PEEP and overdelivery of PIP may be clinically deleterious for term and preterm newborns or infants with larger Crs during resuscitation. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Measurements of Ion and Neutral Fluctuation Changes with Pressure in a Large-Scale Helicon Plasma

NASA Astrophysics Data System (ADS)

Dwyer, R. H.; Fisher, D. M.; Kelly, R. F.; Hatch, M. W.; Gilmore, M.

2017-10-01

Neutral particle dynamics may play an important role both in laboratory plasmas and in the edge of magnetic fusion devices. However, studies of neutral dynamics in these plasmas have been limited to date. Here we report on a basic study of ion and neutral fluctuations as a function of background neutral gas pressure. These experiments have been conducted in helicon discharges in the HelCat (Helicon-Cathode) dual-source plasma device at the University of New Mexico. The goal is to measure changes in ion and neutral density fluctuations with pressure and to gain an improved understanding of plasma-neutral interactions. Langmuir probe, Ar-I LIF, and high-speed imaging measurements of the fluctuations will be presented. Supported by U.S. National Science Foundation Award 1500423 and The University of New Mexico School of Engineering.

Validation of the custo screen 400 ambulatory blood pressure-monitoring device according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Bramlage, Peter; Deutsch, Cornelia; Krüger, Ralf; Wolf, Andreas; Müller, Peter; Zwingers, Thomas; Beime, Beate; Mengden, Thomas

2014-01-01

The aim of the present study was to validate the custo screen 400 ambulatory blood pressure-monitoring (ABPM) device according to the 2010 International Protocol revision of the European Society of Hypertension (ESH-IP). The device can be used for ABPM for up to 72 hours. Systolic and diastolic blood pressure (SBP and DBP, respectively) were sequentially measured in 33 adult subjects (13 males and 20 females) and compared with a standard mercury sphygmomanometer (two observers). A total of 99 comparison pairs were obtained. The custo screen 400 met the requirements of parts 1 and 2 of the ESH-IP revision 2010. The mean difference between the device and reference sphygmomanometer readings was -0.5±4.5 mmHg for SBP and -0.1±3.3 mmHg for DBP. All but one measurement were within the absolute difference of 10 mmHg between the device and the observers for SBP and DBP. The number of absolute differences between the device and the observers within a range of 5 mmHg was 84 of 99 readings for SBP, and 93 of 99 readings for DBP. The custo screen 400 ABPM device met the requirements of the 2010 ESH-IP revision, and hence can be recommended for ABPM in adults. To our knowledge, the custo screen 400 is the first device to pass the revised ESH-IP 2010.

Validation of the custo screen 400 ambulatory blood pressure-monitoring device according to the European Society of Hypertension International Protocol revision 2010

PubMed Central

Bramlage, Peter; Deutsch, Cornelia; Krüger, Ralf; Wolf, Andreas; Müller, Peter; Zwingers, Thomas; Beime, Beate; Mengden, Thomas

2014-01-01

Objective The aim of the present study was to validate the custo screen 400 ambulatory blood pressure-monitoring (ABPM) device according to the 2010 International Protocol revision of the European Society of Hypertension (ESH-IP). The device can be used for ABPM for up to 72 hours. Materials and methods Systolic and diastolic blood pressure (SBP and DBP, respectively) were sequentially measured in 33 adult subjects (13 males and 20 females) and compared with a standard mercury sphygmomanometer (two observers). A total of 99 comparison pairs were obtained. Results The custo screen 400 met the requirements of parts 1 and 2 of the ESH-IP revision 2010. The mean difference between the device and reference sphygmomanometer readings was −0.5±4.5 mmHg for SBP and −0.1±3.3 mmHg for DBP. All but one measurement were within the absolute difference of 10 mmHg between the device and the observers for SBP and DBP. The number of absolute differences between the device and the observers within a range of 5 mmHg was 84 of 99 readings for SBP, and 93 of 99 readings for DBP. Conclusion The custo screen 400 ABPM device met the requirements of the 2010 ESH-IP revision, and hence can be recommended for ABPM in adults. To our knowledge, the custo screen 400 is the first device to pass the revised ESH-IP 2010. PMID:24868162

21 CFR 876.1620 - Urodynamics measurement system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... and pressure in the urinary bladder when it is filled through a catheter with carbon dioxide or water. The device controls the supply of carbon dioxide or water and may also record the electrical activity... electromyography. This generic type of device includes the cystometric gas (carbon dioxide) device, the cystometric...

From Pressure to Path: Barometer-based Vehicle Tracking.

PubMed

Ho, Bo-Jhang; Martin, Paul; Swaminathan, Prashanth; Srivastava, Mani

2015-11-01

Pervasive mobile devices have enabled countless context-and location-based applications that facilitate navigation, life-logging, and more. As we build the next generation of smart cities, it is important to leverage the rich sensing modalities that these numerous devices have to offer. This work demonstrates how mobile devices can be used to accurately track driving patterns based solely on pressure data collected from the device's barometer. Specifically, by correlating pressure time-series data against topographic elevation data and road maps for a given region, a centralized computer can estimate the likely paths through which individual users have driven, providing an exceptionally low-power method for measuring driving patterns of a given individual or for analyzing group behavior across multiple users. This work also brings to bear a more nefarious side effect of pressure-based path estimation: a mobile application can, without consent and without notifying the user, use pressure data to accurately detect an individual's driving behavior, compromising both user privacy and security. We further analyze the ability to predict driving trajectories in terms of the variance in barometer pressure and geographical elevation, demonstrating cases in which more than 80% of paths can be accurately predicted.

Innovative Technology Transfer Partnerships

NASA Technical Reports Server (NTRS)

Kohler, Jeff

2004-01-01

The National Aeronautics and Space Administration (NASA) seeks to license its Advanced Tire and Strut Pressure Monitor (TSPM) technology. The TSPM is a handheld system to accurately measure tire and strut pressure and temperature over a wide temperature range (20 to 120 OF), as well as improve personnel safety. Sensor accuracy, electronics design, and a simple user interface allow operators quick, easy access to required measurements. The handheld electronics, powered by 12-VAC or by 9-VDC batteries, provide the user with an easy-to-read visual display of pressure/temperature or the streaming of pressure/temperature data via an RS-232 interface. When connected to a laptop computer, this new measurement system can provide users with automated data recording and trending, eliminating the chance for data hand-recording errors. In addition, calibration software allows for calibration data to be automatically utilized for the generation of new data conversion equations, simplifying the calibration processes that are so critical to reliable measurements. The design places a high-accuracy pressure sensor (also used as a temperature sensor) as close to the tire or strut measurement location as possible, allowing the user to make accurate measurements rapidly, minimizing the amount of high-pressure volumes, and allowing reasonable distance between the tire or strut and the operator. The pressure sensor attaches directly to the pressure supply/relief valve on the tire and/or strut, with necessary electronics contained in the handheld enclosure. A software algorithm ensures high accuracy of the device over the wide temperature range. Using the pressure sensor as a temperature sensor permits measurement of the actual temperature of the pressurized gas. This device can be adapted to create a portable calibration standard that does not require thermal conditioning. This allows accurate pressure measurements without disturbing the gas temperature. In-place calibration can save considerable time and money and is suitable in many process applications throughout industry.

Validation of the Omron MIT Elite blood pressure device in a pregnant population with large arm circumference.

PubMed

James, Lauren; Nzelu, Diane; Hay, Anna; Shennan, Andrew; Kametas, Nikos A

2017-04-01

The aim of this study was to evaluate the accuracy of the Omron MIT Elite automated device in pregnant women with an arm circumference of or above 32 cm, using the British Hypertension Society validation protocol. Blood pressure was measured sequentially in 46 women of any gestation requiring the use of a large cuff (arm circumference ≥32 cm) alternating between the mercury sphygmomanometer and the Omron MIT Elite device. The Omron MIT Elite achieved an overall D/D grade with a mean of the device-observer difference being 7.17±6.67 and 9.31±6.59 for systolic and diastolic blood pressure respectively. Interobserver accuracy was 94.6% for systolic and 95% for diastolic readings within 5 mmHg. The Omron MIT Elite overestimates blood pressure and has failed the British Hypertension Society protocol requirements. Therefore, it cannot be recommended for use in pregnant women with an arm circumference of or above 32 cm.

Mother-offspring aggregation in home versus conventional blood pressure in the Tohoku Study of Child Development (TSCD).

PubMed

Asayama, Kei; Staessen, Jan A; Hayashi, Katsuhisa; Hosaka, Miki; Tatsuta, Nozomi; Kurokawa, Naoyuki; Satoh, Michihiro; Hashimoto, Takanao; Hirose, Takuo; Obara, Taku; Metoki, Hirohito; Inoue, Ryusuke; Kikuya, Masahiro; Ohkubo, Takayoshi; Nakai, Kunihiko; Imai, Yutaka; Satoh, Hiroshi

2012-08-01

Few studies described the home blood pressure (HBP) in young children. Using intrafamilial correlations of blood pressure as research focus, we assessed the feasibility of HBP monitoring in this age group. We enrolled 382 mothers (mean age 38.8 years) and singletons (7.0 years) in theTohoku Study of Child Development.We measured their conventional blood pressure (CBP; single reading) at an examination centre. Participants monitored HBP in the morning. We used the OMRON HEM-70801C for CBP and HBP measurement. In a separate group of 84 children (mean age 7.7 years), we compared blood pressure readings obtained by the OMRON monitor and the Dinamap Pro 100, a device approved by FDA for use in children. We used correlation coefficients as measure of intrafamilial aggregation, while accounting for the mothers' age, body mass index, heart rate and smoking and drinking habits and the children's age, height, and heart rate. Mother-offspring correlations were closer (P < or = 0.003) for HBP than CBP for systolic pressure [0.28 (P < 0.0001) vs 0.06 (P = 0.26)] and diastolic pressure [0.28 (P < 0.0001) vs 0.02 (P = 0.65)].The between-device differences (OMRON minus Dinamap) averaged 7.8 +/- 6.0 mmHg systolic and 5.8 +/- 5.5 mmHg diastolic. HBP monitoring is an easily applicable method to assess intrafamilial blood pressure aggregation in young children and outperforms CBP. Validation protocols for HBP devices in young children need revision, because the Korotkoff method is not practicable at this age and there is no agreed alternative reference method.

Validation of four automatic devices for self-measurement of blood pressure according to the international protocol of the European Society of Hypertension.

PubMed

Topouchian, Jirar; Agnoletti, Davide; Blacher, Jacques; Youssef, Ahmed; Ibanez, Isabel; Khabouth, Jose; Khawaja, Salwa; Beaino, Layale; Asmar, Roland

2011-01-01

Four oscillometric devices for self-measurement of blood pressure (SBPM) were evaluated according to the European Society of Hypertension (ESH) international protocol and its 2010 revision in four separate studies. The Omron® M2, Omron M3, and Omron M6 measure blood pressure (BP) at the brachial level, while the Omron R2 measures BP at the wrist level. The international protocol requires a total number of 33 subjects in which the validation is performed. The Omron M2 and Omron R2 were validated in 2009 according to the ESH international protocol, while the Omron M3 and Omron M6 were validated in 2010-2011 according to the 2010 ESH international protocol revision. The protocol procedures were followed precisely. All four tested devices passed the validation process. The mean differences between the device and mercury readings were 2.7 ± 5.0 and -1.4 ± 3.2 mmHg for systolic and diastolic BP, respectively, using the Omron M2 device, and 1.7 ± 3.2 and -0.9 ± 2.6 mmHg using the Omron M3, 1.6 ± 2.9 and -0.9 ± 2.5 mmHg using the Omron M6, and -1.1 ± 4.8 and -0.9 ± 4.3 mmHg using the Omron R2. Readings from the Omron M2, Omron M3, Omron M6, and Omron R2, differing by less than 5, 10, and 15 mmHg, fulfill the ESH international protocol and its 2010 revision requirements. Therefore, each of these four devices can be used by patients for SBPM.

The importance of valve alignment in determining the pressure/flow characteristics of differential pressure shunt valves with anti-gravity devices.

PubMed

Francel, P C; Stevens, F A; Tompkins, P; Pollay, M

2001-02-01

The proper functioning of shunt valves in vivo is dependent on many factors, including the valve itself, the anti-siphon device or ASD (if included), patency of inlet and outlet tubing, and location of the valve. One important, but sometimes overlooked, consideration in valve function is the valve location relative to the tip of the ventricular inlet catheter. As with any pressure measurement, the zero or reference position is an important concept. In the case of shunt valves, the position of the proximal inlet catheter tip is fixed and therefore serves as the reference point for all pressure measurements. This study was conducted to document the importance of this relationship for the pressure/flow characteristics of the shunt valve. We bench-tested differential pressure valves (with integral anti-gravity devices; AGDs) from three manufacturers. Valves were connected to an "infinite" reservoir, and the starting head pressure for each was determined from product inserts. The inlet catheter tip was fixed at this position, and the valve body was moved in relation to the inlet catheter tip. Outflow rates were determined gravimetrically for positions varying between 4 cm above and 8 cm below the inlet catheter tip. All differential pressure valves utilized in this study that contained AGDs showed significant increases in outflow rate as the valve body was moved incrementally below the level of the inlet catheter tip. To allow functioning as a zero-hydrostatic pressure differential pressure valve, the AGD and the inlet catheter tip should be aligned at the same horizontal level.

Telemetric Intracranial Pressure Monitoring with the Raumedic Neurovent P-tel.

PubMed

Antes, Sebastian; Tschan, Christoph A; Heckelmann, Michael; Breuskin, David; Oertel, Joachim

2016-07-01

Devices enabling long-term intracranial pressure monitoring have been demanded for some time. The first solutions using telemetry were proposed in 1967. Since then, many other wireless systems have followed but some technical restrictions have led to unacceptable measurement uncertainties. In 2009, a completely revised telemetric pressure device called Neurovent P-tel was introduced to the market. This report reviews technical aspects, handling, possibilities of data analysis, and the efficiency of the probe in clinical routine. The telemetric device consists of 3 main parts: the passive implant, the active antenna, and the storage monitor. The implant with its parenchymal pressure transducer is inserted via a frontal burr hole. Pressure values can be registered with a frequency of 1 Hz or 5 Hz. Telemetrically gathered data can be viewed on the storage monitor or saved on a computer for detailed analyses. A total of 247 patients with suspected (n = 123) or known (n = 124) intracranial pressure disorders underwent insertion of the telemetric pressure probe. A detailed analysis of the long-term intracranial pressure profile including mean values, maximum and negative peaks, pathologic slow waves, and pulse pressure amplitudes is feasible using the detection rate of 5 Hz. This enables the verification of suspected diagnoses as normal-pressure hydrocephalus, benign intracranial hypertension, shunt malfunction, or shunt overdrainage. Long-term application also facilitates postoperative surveillance and supports valve adjustments of shunt-treated patients. The presented telemetric measurement system is a valuable and effective diagnostic tool in selected cases. Copyright © 2016 Elsevier Inc. All rights reserved.

A mainstream monitoring system for respiratory CO2 concentration and gasflow.

PubMed

Yang, Jiachen; Chen, Bobo; Burk, Kyle; Wang, Haitao; Zhou, Jianxiong

2016-08-01

Continuous respiratory gas monitoring is an important tool for clinical monitoring. In particular, measurement of respiratory [Formula: see text] concentration and gasflow can reflect the status of a patient by providing parameters such as volume of carbon dioxide, end-tidal [Formula: see text] respiratory rate and alveolar deadspace. However, in the majority of previous work, [Formula: see text] concentration and gasflow have been studied separately. This study focuses on a mainstream system which simultaneously measures respiratory [Formula: see text] concentration and gasflow at the same location, allowing for volumetric capnography to be implemented. A non-dispersive infrared monitor is used to measure [Formula: see text] concentration and a differential pressure sensor is used to measure gasflow. In developing this new device, we designed a custom airway adapter which can be placed in line with the breathing circuit and accurately monitor relevant respiratory parameters. Because the airway adapter is used both for capnography and gasflow, our system reduces mechanical deadspace. The finite element method was used to design the airway adapter which can provide a strong differential pressure while reducing airway resistance. Statistical analysis using the coefficient of variation was performed to find the optimal driving voltage of the pressure transducer. Calibration between variations and flows was used to avoid pressure signal drift. We carried out targeted experiments using the proposed device and confirmed that the device can produce stable signals.

Cardiopulmonary monitoring in Thai ICUs (ICU-rESOURCE I Study).

PubMed

Chittawatanarat, Kaweesak; Wattanathum, Anan; Chaiwat, Onuma

2014-01-01

Cardiopulmonary monitoring (CPM) is rapidly progressing but data regarding CPM in Thai ICUs was unavailable. The objective of this study was to describe the situation, and gaps of CPM in Thai ICUs. Data were retrieved from the ICU-RESOURCE I study database survey CPM was divided into two aspects of device and measurement methods. These were categorized by device availability grading (AG), device availability per bed (DPB) and numeric frequency grading scale (FGS). Device availability was compared between academic and non-academic ICUs. Gap analysis of DPB and FGS was performed. Statistical significant difference was defined as p-value < 0.05. One hundred and fifty-five ICUs across Thailand participated in this study. Academic ICUs had significantly more devices available in new equipment with p < 0.05 (Vigilio, PiCCO, NICOM, esophageal pressure monitoring, transcutaneous PO2, electrical impedance tomography of lung) as well as measurement methods (stroke volume variation [SVV], pulse pressure variation [PPC], central venous oxygen saturation [ScvO2], lung mechanics). Most of new and higher technological devices had low density and few were available in all of Thai ICUs. However, in gap analysis, although these new devices and measurement techniques were available in ICUs, they were not frequently utilized. New technology devices of CPM had more availability in ACAD than in non-ACAD ICUs. Formal continuous training in new measurement methods should be established for reducing the availability and utilization gap (Thai Clinical Trial Registry: TCTR-201200005).

Tissue-Informative Mechanism for Wearable Non-invasive Continuous Blood Pressure Monitoring

NASA Astrophysics Data System (ADS)

Woo, Sung Hun; Choi, Yun Young; Kim, Dae Jung; Bien, Franklin; Kim, Jae Joon

2014-10-01

Accurate continuous direct measurement of the blood pressure is currently available thru direct invasive methods via intravascular needles, and is mostly limited to use during surgical procedures or in the intensive care unit (ICU). Non-invasive methods that are mostly based on auscultation or cuff oscillometric principles do provide relatively accurate measurement of blood pressure. However, they mostly involve physical inconveniences such as pressure or stress on the human body. Here, we introduce a new non-invasive mechanism of tissue-informative measurement, where an experimental phenomenon called subcutaneous tissue pressure equilibrium is revealed and related for application in detection of absolute blood pressure. A prototype was experimentally verified to provide an absolute blood pressure measurement by wearing a watch-type measurement module that does not cause any discomfort. This work is supposed to contribute remarkably to the advancement of continuous non-invasive mobile devices for 24-7 daily-life ambulatory blood-pressure monitoring.

Surface EMG and intra-socket force measurement to control a prosthetic device

NASA Astrophysics Data System (ADS)

Sanford, Joe; Patterson, Rita; Popa, Dan

2015-06-01

Surface electromyography (SEMG) has been shown to be a robust and reliable interaction method allowing for basic control of powered prosthetic devices. Research has shown a marked decrease in EMG-classification efficiency throughout activities of daily life due to socket shift and movement and fatigue as well as changes in degree of fit of the socket throughout the subject's lifetime. Users with the most severe levels of amputation require the most complex devices with the greatest number of degrees of freedom. Controlling complex dexterous devices with limited available inputs requires the addition of sensing and interaction modalities. However, the larger the amputation severity, the fewer viable SEMG sites are available as control inputs. Previous work reported the use of intra-socket pressure, as measured during wrist flexion and extension, and has shown that it is possible to control a powered prosthetic device with pressure sensors. In this paper, we present data correlations of SEMG data with intra-socket pressure data. Surface EMG sensors and force sensors were housed within a simulated prosthetic cuff fit to a healthy-limbed subject. EMG and intra-socket force data was collected from inside the cuff as a subject performed pre-defined grip motions with their dominant hand. Data fusion algorithms were explored and allowed a subject to use both intra-socket pressure and SEMG data as control inputs for a powered prosthetic device. This additional input modality allows for an improvement in input classification as well as information regarding socket fit through out activities of daily life.

Development of Clinically Relevant Implantable Pressure Sensors: Perspectives and Challenges

PubMed Central

Clausen, Ingelin; Glott, Thomas

2014-01-01

This review describes different aspects to consider when developing implantable pressure sensor systems. Measurement of pressure is in general highly important in clinical practice and medical research. Due to the small size, light weight and low energy consumption Micro Electro Mechanical Systems (MEMS) technology represents new possibilities for monitoring of physiological parameters inside the human body. Development of clinical relevant sensors requires close collaboration between technological experts and medical clinicians. Site of operation, size restrictions, patient safety, and required measurement range and resolution, are only some conditions that must be taken into account. An implantable device has to operate under very hostile conditions. Long-term in vivo pressure measurements are particularly demanding because the pressure sensitive part of the sensor must be in direct or indirect physical contact with the medium for which we want to detect the pressure. New sensor packaging concepts are demanded and must be developed through combined effort between scientists in MEMS technology, material science, and biology. Before launching a new medical device on the market, clinical studies must be performed. Regulatory documents and international standards set the premises for how such studies shall be conducted and reported. PMID:25248071

Development of clinically relevant implantable pressure sensors: perspectives and challenges.

PubMed

Clausen, Ingelin; Glott, Thomas

2014-09-22

This review describes different aspects to consider when developing implantable pressure sensor systems. Measurement of pressure is in general highly important in clinical practice and medical research. Due to the small size, light weight and low energy consumption Micro Electro Mechanical Systems (MEMS) technology represents new possibilities for monitoring of physiological parameters inside the human body. Development of clinical relevant sensors requires close collaboration between technological experts and medical clinicians.  Site of operation, size restrictions, patient safety, and required measurement range and resolution, are only some conditions that must be taken into account. An implantable device has to operate under very hostile conditions. Long-term in vivo pressure measurements are particularly demanding because the pressure sensitive part of the sensor must be in direct or indirect physical contact with the medium for which we want to detect the pressure. New sensor packaging concepts are demanded and must be developed through combined effort between scientists in MEMS technology, material science, and biology. Before launching a new medical device on the market, clinical studies must be performed. Regulatory documents and international standards set the premises for how such studies shall be conducted and reported.

Measurement of Oil-Film Pressures in Journal Bearings under Constant and Variable Loads

NASA Technical Reports Server (NTRS)

Buske, A.; Rolli, W.

1949-01-01

In a study of journal bearings, the measurement of the oil-film strength produces some significant information. A new instrument is described by means of which the pressure of the oil film in bearings (under constant or alternating load) can be measured and recorded. With this device, the pressure distribution in the lubricating film of a bearing bushing was measured (under different operating conditions on a journal bearing) in the pulsator-bearing-testing machine. These tests are described and discussed in the present report.

Validation of the blood pressure measurement device Erkameter 125 PRO according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Beime, Beate; Deutsch, Cornelia; Krüger, Ralf; Zimmermann, Erik; Bramlage, Peter

2016-12-01

The aim of the present study was to validate the blood pressure (BP) measurement device Erkameter 125 PRO according to the International Protocol revision 2010 of the European Society of Hypertension (ESH-IP2). In 33 patients aged 32-79 years, BP measurements were performed alternately using the Erkameter 125 PRO and the reference mercury sphygmomanometer according to ESH-IP revision 2010. For the analysis, a total of 99 comparisons were included. All absolute differences between the test device and the reference were within 10 mmHg for systolic blood pressure (SBP), and all except one for diastolic blood pressure (DBP). A total of 93 out of 99 comparisons for SBP showed an absolute difference within 5 mmHg and 92 out of 99 for DBP. The mean±SD difference between the Erkameter 125 PRO and the standard reference was -0.5±3.5 mmHg for SBP and 0.5±3.5 mmHg for DBP. As to part 2 of ESH-IP 2010, all patients had a minimum of two out of three measurements within 5 mmHg difference for SBP and 31 out of 33 patients for DBP. The Erkameter 125 PRO fulfilled the requirements of parts 1 and 2 of the ESH-IP revision 2010 and can be recommended for office BP measurements in adults.

Performance of the Colson MAM BP 3AA1-2 automatic blood pressure monitor according to the European Society of Hypertension validation protocol.

PubMed

Pereira, Telmo; Maldonado, João

2005-11-01

To evaluate the performance of the Colson MAM BP 3AA1-2 oscillometric automatic blood pressure monitor according to the validation protocol of the European Society of Hypertension, testing its suitability for self-measurement of blood pressure. The performance of the device was assessed in relation to various clinical variables, including age, gender, body mass index, arm circumference and arterial stiffness. 33 subjects (15 men and 18 women), with a mean age of 47 +/- 10 years, were studied according to the procedures laid down in the European Society of Hypertension validation protocol. Sequential same-arm blood pressure measurements were made, alternating between a mercury standard and the automatic device. The differences among the test-control measurements were assessed and divided into categorization zones of 5, 10 and 15 mmHg discrepancy. Aortic pulse wave velocity was assessed in all subjects with a Complior device (Colson, Paris). The Colson MAM BP 3AA1-2 passed all three phases of the protocol for both systolic and diastolic blood pressure. The mean differences between the test and control measurements were -1.0 +/- 5.0 mmHg for systolic blood pressure and -1.1 +/- 4.1 mmHg for diastolic blood pressure. Both standard deviations are well below the 8 mmHg limit proposed by the Association for the Advancement of Medical Instrumentation. The predictive value of various clinical variables for the discrepancies was assessed by a regression model analysis, with no variable being found that independently undermined the performance of the monitor. In another regression analysis, we found a similar relation between test and control blood pressures and aortic pulse wave velocity, a widely recognized and validated index of target organ damage. These data show that the Colson MAM BP 3AA1-2 satisfies the quality requirements proposed by the European Society of Hypertension, demonstrating its suitability for inclusion in integrated programs of clinical surveillance based on self-measurement of blood pressure. The uniformity of its performance over a wide spectrum of clinical characteristics and the relation found with pulse wave velocity further reinforce its clinical validity.

Validation of a smartphone auscultatory blood pressure kit Accutension XYZ-110 in adults according to the ANSI/AAMI/ISO 81060-2: 2013 standard.

PubMed

Chu, Guang; Zhang, Zhi; Xu, Mengdan; Huang, Daini; Dai, Qiuyan

2017-10-01

The aim of this study was to validate the accuracy of the Accutension XYZ-110 blood pressure (BP) kit according to the American National Standards Institute/Association for the Advancement of Medical Instrumentation/International Organization for Standardization (ANSI/AAMI/ISO) 81060-2:2013 standard. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured simultaneously on the same arm in 85 Chinese adults (female : male=48 : 37) with a mean age of 43.2 years using the mercury sphygmomanometer (two observers) and the Accutension XYZ-110 device (one supervisor). The ANSI/AAMI/ISO 81060-2:2013 standard for the validation of BP-measuring devices in adults was followed precisely. A total of 255 comparison pairs were obtained for analysis. The mean device-observer difference in the 255 separate BP data pairs was 2.45±2.24 mmHg for SBP and 0.69±2.09 mmHg for DBP. The data were in accordance with the criterion 1 of the ANSI/AAMI/ISO 81060-2:2013 standard requirements (≤5±8 mmHg). In addition, the mean device-observer difference of the 85 participants was 2.45±1.47 mmHg for SBP and 0.69±1.36 mmHg for DBP. The device accuracy also fulfilled the criterion 2 with the SD of less than or equal to 6.47 for SBP and less than or equal to 6.90 mmHg for DBP. The Accutension XYZ-110 BP kit fulfilled the requirements of the ANSI/AAMI/ISO 81060-2:2013 standard, and hence could be recommended for both clinical and self/home BP measurement in adults.

Can an electronic device with a single cuff be accurate in a wide range of arm size? Validation of the Visomat Comfort 20/40 device for home blood pressure monitoring.

PubMed

Stergiou, G S; Tzamouranis, D; Nasothimiou, E G; Protogerou, A D

2008-11-01

An appropriate cuff according to the individual's arm circumference is recommended with all blood pressure (BP) monitors. An electronic device for home monitoring has been developed (Visomat Comfort 20/40) that estimates the individual's arm circumference by measuring the cuff filing volume and makes an adjustment of measured BP taking into account the estimated arm circumference. Thus the manufacturer recommends the use of a single cuff for arm circumference 23-43 cm. The device accuracy was assessed using the European Society of Hypertension International Protocol. Simultaneous BP measurements were obtained in 33 adults by two observers (connected mercury sphygmomanometers) four times, sequentially with three measurements taken using the tested device. Absolute device-observer BP differences were classified into < or =5, < or =10 and < or =15 mm Hg zones. For each participant the number of measurements with a difference < or =5 mm Hg was calculated. The device produced 60/89/97 measurements within 5/10/15 mm Hg respectively for systolic BP, and 72/97/98 for diastolic. Twenty-three subjects had at least two of their systolic BP differences < or =5 mm Hg and three had no differences < or =5 mm Hg (for diastolic 27 and 1, respectively). Mean device-observer BP difference (systolic/diastolic) was 3.7 +/- 5.6/-1.5 +/- 4.7 mm Hg (4.7 +/- 4.9/ - 1.7 +/- 4.3 in arm circumference 23-29 cm [39 readings] and 3.1 +/- 5.9/-1.4 +/- 5.0 in arm 30-34 cm [60 readings], P=NS). In conclusion, the device fulfils the International Protocol requirements and can be recommended for clinical use. Interestingly, the device was accurate using a single cuff in a wide range of arm circumference (23-34 cm). This study provides no information about the device accuracy in larger arms.

[Circulatory Function Tests for Home & Community Use.

PubMed

Shimetani, Naoto

2016-05-01

Currently, the main circulatory function-testing tools for home use are blood pressure monitors and elec- trocardiography devices. Just like blood pressure monitors that are already widespread for home use, some devices with an electrocardiographic function have recently become available for purchase for personal use by the general public. On the other hand, clinic equipment on loan from doctors to patients in need can perform circulatory function tests like 24-hour ambulatory blood pressure monitoring (ABPM), Holter monitoring, and real-time electrocardiography. We introduce the actual clinical usage of ABPM and real-time electro- cardiography, and discuss the usefulness of these procedures. ABPM uses a blood pressure measurement device worn on the body for 24 hours a day to measure blood pressure at regular intervals. This makes it possible to check blood pressure changes throughout the day in a way in which conventional home-use blood pressure monitors cannot, like during sleep. This method al- lows the identification of masked hypertension like early-morning and nocturnal hypertension, stress hyper- tension including workplace hypertension, and white coat hypertension that only occurs in the doctor's office. Under routine care, there are few opportunities to perform electrocardiography at the time a patient is experiencing symptoms. Now, real-time electrocardiography has begun to be used in routine care, and pa- tients can record an electrocardiogram by themselves anytime, anywhere, and send the data by telephone or the Internet for analysis and diagnosis. Transmission-capable electrocardiography devices can play an im- portant role in the event of dangerous symptoms like arrhythmia, angina, or acute myocardial infarction. The spread of ABPM and event heart monitors is likely to make the early treatment and prevention of stroke and heart disease possible. We are expecting rapid development in this field in the future.

[Comparison of invasive blood pressure measurement in the aorta with indirect oscillometric blood pressure measurement at the wrist and forearm].

PubMed

Saul, F; Aristidou, Y; Klaus, D; Wiemeyer, A; Lösse, B

1995-09-01

Indirectly measured blood pressure at the wrist or upper arm was compared with directly measured values in the aortic arch during routinely performed diagnostic cardiac catheterization in 100 patients (31-80 years, mean 59.3 years, 60% males). The noninvasive measurements were carried out by oscillometric devices, NAiS Blood Pressure Watch for measurements at the wrist, and Hestia OZ80 at the upper arm. Systolic blood pressure measured at the wrist was 4.3 +/- 14.1 mm Hg, and the diastolic value 6.0 +/- 8.9 mm Hg higher than when measured at the aortic arch; the difference was significant in both cases. Correlation coefficients were 0.85 for systolic and 0.71 for diastolic blood pressure. In 16% of the patients the systolic blood pressure at the wrist differed more than +/- 20 mm Hg. The diastolic blood pressure at the wrist measured more than +/- 20 mm Hg higher than in the aorta in 5% of the patients. At the upper arm mean systolic values were not different to the aorta. The diastolic pressure was 9.3 +/- 9.8 mm Hg higher in the aorta than at the upper arm. To verify the accuracy of values measured with the NAiS Blood Pressure Watch compared with the standard technique at the upper arm, sequential measurements were made at wrist and ipsilateral upper arm in the same group of 100 patients. The systolic blood pressure at the left wrist was 3.4 +/- 13.3 mm Hg higher and the diastolic pressure 3.8 +/- 9.5 mm Hg lower than at the upper arm. Only 53% of systolic values lay within a range of +/- 10 mm Hg. The correspondence between wrist and upper arm values was better for diastolic blood pressure, the values differing by less than +/- 10 mm Hg in two-thirds of patients. Self-measurement of arterial blood pressure with an oscillometric device at the wrist can be recommended only in individual cases with a difference of simultaneously measured values at the upper arm of less than +/- 10 mm Hg for systolic and diastolic blood pressures. The standard method for indirectly measuring arterial blood pressure remains the measurement at the upper arm site, which nevertheless showed a systolic pseudohypertension (deviation of more than 10 mm Hg) in comparison to the invasively measured values in 15% of our selected patients and a diastolic pseudohypertension (deviation of more than 15 mm Hg) in 23% of the patients.

High-temperature-measuring device

DOEpatents

Not Available

1981-01-27

A temperature measuring device for very high design temperatures (to 2000/sup 0/C) is described. The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensonally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

High temperature measuring device

DOEpatents

Tokarz, Richard D.

1983-01-01

A temperature measuring device for very high design temperatures (to 2,000.degree. C.). The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensionally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

Development of crawler type device using new measuring system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maruyama, T.; Sasaki, T.; Yagi, T.

1995-08-01

This paper reports the development and field application of a new device which examine shell to shell weld joints of RPV. In a BWR type nuclear power plant, there is narrow space around the Reactor Pressure Vessel (RPV) because RPV is enclosed by the Reactor Shield Wall (RSW) and thermal insulations. The developed device is characterized by a new position measuring system and magnet wheels for driving. The new position measuring system uses laser beam and ultrasonic wave. The magnet wheels make the device travel freely in the narrow space between RPV and insulation. This device is tested on mock-upsmore » and applied examination of RPVs to verify field applicability.« less

Questionable accuracy of home blood pressure measurements in the obese population - Validation of the Microlife WatchBP O3® and Omron RS6® devices according to the European Society of Hypertension-International Protocol.

PubMed

Azaki, Alaa; Diab, Reem; Harb, Aya; Asmar, Roland; Chahine, Mirna N

2017-01-01

Two oscillometric devices, the Microlife WatchBP O3 ® and the Omron RS6 ® , designed for self-blood pressure measurement were evaluated according to the European Society of Hypertension (ESH)-International Protocol (IP) Revision 2010 in the obese population. The Microlife WatchBP O3 measures blood pressure (BP) at the brachial level and the Omron RS6 measures BP at the wrist level. The ESH-IP revision 2010 includes a total of 33 subjects. The difference between observers' and device BP values was calculated for each measure. A total of 99 pairs of BP differences were classified into three categories (≤5, ≤10, and ≤15 mmHg). The protocol procedures were followed precisely in each of the two studies. Microlife WatchBP O3 and Omron RS6 failed to fulfill the criteria of the ESH-IP. The mean differences between the device and the mercury readings were: 0.3±7.8 mmHg and -1.9±6.4 mmHg for systolic BP and diastolic BP, respectively, for Microlife WatchBP O3, and 2.7±9.9 mmHg for SBP and 3.5±11.1 mmHg for diastolic BP for Omron RS6. Microlife WatchBP O3 and Omron RS6 readings differing from the mercury standard by more than 5, 10, and 15 mmHg failed to fulfill the ESH-IP revision 2010 requirements in obese subjects. Therefore, the two devices cannot be recommended for use in obese subjects.

On-line fast response device and method for measuring dissolved gas in a fluid

DOEpatents

Tutu, Narinder Kumar [Manorville, NY

2011-01-11

A method and device for the measurement of dissolved gas within a fluid. The fluid, substantially a liquid, is pumped into a pipe. The flow of the fluid is temporally restricted, creating one or more low pressure regions. A measurement indicative of trapped air is taken before and after the restriction. The amount of dissolved air is calculated from the difference between the first and second measurements. Preferably measurements indicative of trapped air is obtained from one or more pressure transducers, capacitance transducers, or combinations thereof. In the alternative, other methods such as those utilizing x-rays or gamma rays may also be used to detect trapped air. Preferably, the fluid is a hydraulic fluid, whereby dissolved air in the fluid is detected.

An experimental study of perforated muzzle brakes

NASA Astrophysics Data System (ADS)

Dillon, R. E., Jr.; Nagamatsu, H. T.

1984-06-01

A firing test was conducted to examine the recoil efficiency and blast characteristics of perforated muzzle brakes fitted to a 20 mm cannon. Recoil impulse blast overpressures, muzzle velocity, sequential spark shadowgraphs, and photographs of the muzzle flash structure were obtained. Three different nuzzle devices were used with one device equipped with pressure transducers to measure the static pressure in the brake. Experimental results are compared with the earlier predictions of Dillon and Nagamatsu.

Evaluation of a Low-Cost Bubble CPAP System Designed for Resource-Limited Settings.

PubMed

Bennett, Desmond J; Carroll, Ryan W; Kacmarek, Robert M

2018-04-01

Respiratory compromise is a leading contributor to global neonatal death. CPAP is a method of treatment that helps maintain lung volume during expiration, promotes comfortable breathing, and improves oxygenation. Bubble CPAP is an effective alternative to standard CPAP. We sought to determine the reliability and functionality of a low-cost bubble CPAP device designed for low-resource settings. The low-cost bubble CPAP device was compared to a commercially available bubble CPAP system. The devices were connected to a lung simulator that simulated neonates of 4 different weights with compromised respiratory mechanics (∼1, ∼3, ∼5, and ∼10 kg). The devices' abilities to establish and maintain pressure and flow under normal conditions as well as under conditions of leak were compared. Multiple combinations of pressure levels (5, 8, and 10 cm H 2 O) and flow levels (3, 6, and 10 L/min) were tested. The endurance of both devices was also tested by running the systems continuously for 8 h and measuring the changes in pressure and flow. Both devices performed equivalently during the no-leak and leak trials. While our testing revealed individual differences that were statistically significant and clinically important (>10% difference) within specific CPAP and flow-level settings, no overall comparisons of CPAP or flow were both statistically significant and clinically important. Each device delivered pressures similar to the desired pressures, although the flows delivered by both machines were lower than the set flows in most trials. During the endurance trials, the low-cost device was marginally better at maintaining pressure, while the commercially available device was better at maintaining flow. The low-cost bubble CPAP device evaluated in this study is comparable to a bubble CPAP system used in developed settings. Extensive clinical trials, however, are necessary to confirm its effectiveness. Copyright © 2018 by Daedalus Enterprises.

40 CFR 60.256 - Continuous monitoring requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... device is to be certified by the manufacturer to be accurate within ±1 inch water gauge. (B) A monitoring device for the continuous measurement of the water supply pressure to the control equipment. The monitoring device is to be certified by the manufacturer to be accurate within ±5 percent of design water...

The SNaP system: biomechanical and animal model testing of a novel ultraportable negative-pressure wound therapy system.

PubMed

Fong, Kenton D; Hu, Dean; Eichstadt, Shaundra; Gupta, Deepak M; Pinto, Moshe; Gurtner, Geoffrey C; Longaker, Michael T; Lorenz, H Peter

2010-05-01

Negative-pressure wound therapy is traditionally achieved by attaching an electrically powered pump to a sealed wound bed and applying subatmospheric pressure by means of gauze or foam. The Smart Negative Pressure (SNaP) System (Spiracur, Inc., Sunnyvale, Calif.) is a novel ultraportable negative-pressure wound therapy system that does not require an electrically powered pump. Negative pressure produced by the SNaP System, and a powered pump, the wound vacuum-assisted closure advanced-therapy system (Kinetic Concepts, Inc., San Antonio, Texas), were compared in vitro using bench-top pressure sensor testing and microstrain and stress testing with pressure-sensitive film and micro-computed tomographic scan analysis. In addition, to test in vivo efficacy, 10 rats underwent miniaturized SNaP (mSNaP) device placement on open wounds. Subject rats were randomized to a system activation group (approximately -125 mmHg) or a control group (atmospheric pressure). Wound measurements and histologic data were collected for analysis. Bench measurement revealed nearly identical negative-pressure delivery and mechanical strain deformation patterns between both systems. Wounds treated with the mSNaP System healed faster, with decreased wound size by postoperative day 7 (51 percent versus 12 percent reduction; p < 0.05) and had more rapid complete reepithelialization (21 days versus 32 days; p < 0.05). The mSNaP device also induced robust granulation tissue formation. The SNaP System and an existing electrically powered negative-pressure wound therapy system have similar biomechanical properties and functional wound-healing benefits. The potential clinical efficacy of the SNaP device for the treatment of wounds is supported.

Disease management: remote monitoring in heart failure patients with implantable defibrillators, resynchronization devices, and haemodynamic monitors.

PubMed

Abraham, William T

2013-06-01

Heart failure represents a major public health concern, associated with high rates of morbidity and mortality. A particular focus of contemporary heart failure management is reduction of hospital admission and readmission rates. While optimal medical therapy favourably impacts the natural history of the disease, devices such as cardiac resynchronization therapy devices and implantable cardioverter defibrillators have added incremental value in improving heart failure outcomes. These devices also enable remote patient monitoring via device-based diagnostics. Device-based measurement of physiological parameters, such as intrathoracic impedance and heart rate variability, provide a means to assess risk of worsening heart failure and the possibility of future hospitalization. Beyond this capability, implantable haemodynamic monitors have the potential to direct day-to-day management of heart failure patients to significantly reduce hospitalization rates. The use of a pulmonary artery pressure measurement system has been shown to significantly reduce the risk of heart failure hospitalization in a large randomized controlled study, the CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients (CHAMPION) trial. Observations from a pilot study also support the potential use of a left atrial pressure monitoring system and physician-directed patient self-management paradigm; these observations are under further investigation in the ongoing LAPTOP-HF trial. All these devices depend upon high-intensity remote monitoring for successful detection of parameter deviations and for directing and following therapy.

Pressure cell for investigations of solid-liquid interfaces by neutron reflectivity.

PubMed

Kreuzer, Martin; Kaltofen, Thomas; Steitz, Roland; Zehnder, Beat H; Dahint, Reiner

2011-02-01

We describe an apparatus for measuring scattering length density and structure of molecular layers at planar solid-liquid interfaces under high hydrostatic pressure conditions. The device is designed for in situ characterizations utilizing neutron reflectometry in the pressure range 0.1-100 MPa at temperatures between 5 and 60 °C. The pressure cell is constructed such that stratified molecular layers on crystalline substrates of silicon, quartz, or sapphire with a surface area of 28 cm(2) can be investigated against noncorrosive liquid phases. The large substrate surface area enables reflectivity to be measured down to 10(-5) (without background correction) and thus facilitates determination of the scattering length density profile across the interface as a function of applied load. Our current interest is on the stability of oligolamellar lipid coatings on silicon surfaces against aqueous phases as a function of applied hydrostatic pressure and temperature but the device can also be employed to probe the structure of any other solid-liquid interface.

High pressure metrology for industrial applications

NASA Astrophysics Data System (ADS)

Sabuga, Wladimir; Rabault, Thierry; Wüthrich, Christian; Pražák, Dominik; Chytil, Miroslav; Brouwer, Ludwig; Ahmed, Ahmed D. S.

2017-12-01

To meet the needs of industries using high pressure technologies, in traceable, reliable and accurate pressure measurements, a joint research project of the five national metrology institutes and the university was carried out within the European Metrology Research Programme. In particular, finite element methods were established for stress-strain analysis of elastic and nonlinear elastic-plastic deformation, as well as of contact processes in pressure-measuring piston-cylinder assemblies, and high-pressure components at pressures above 1 GPa. New pressure measuring multipliers were developed and characterised, which allow realisation of the pressure scale up to 1.6 GPa. This characterisation is based on research including measurements of material elastic constants by the resonant ultrasound spectroscopy, hardness of materials of high pressure components, density and viscosity of pressure transmitting liquids at pressures up to 1.4 GPa and dimensional measurements on piston-cylinders. A 1.6 GPa pressure system was created for operation of the 1.6 GPa multipliers and calibration of high pressure transducers. A transfer standard for 1.5 GPa pressure range, based on pressure transducers, was built and tested. Herewith, the project developed the capability of measuring pressures up to 1.6 GPa, from which industrial users can calibrate their pressure measurement devices for accurate measurements up to 1.5 GPa.

Evaluation of different near-infrared spectroscopy technologies for assessment of tissue oxygen saturation during a vascular occlusion test.

PubMed

Steenhaut, Kevin; Lapage, Koen; Bové, Thierry; De Hert, Stefan; Moerman, Annelies

2017-12-01

An increasing number of NIRS devices are used to provide measurements of peripheral tissue oxygen saturation (S t O 2 ). The aim of the present study is to test the hypothesis that despite technological differences between devices, similar trend values will be obtained during a vascular occlusion test. The devices compared are NIRO-200NX, which measures S t O 2 and oxyhemoglobin by spatially resolved spectroscopy and the Beer-Lambert law, respectively, and INVOS 5100C and Foresight Elite, which both measure S t O 2 with the Beer-Lambert law, enhanced with the spatial resolution technique. Forty consenting adults scheduled for CABG surgery were recruited. The respective sensors of the three NIRS devices were applied over the brachioradial muscle. Before induction of anesthesia, 3 min of ischemia were induced by inflating a blood pressure cuff at the upper arm, whereafter cuff pressure was rapidly released. Tissue oxygenation measurements included baseline, minimum and maximum values, desaturation and resaturation slopes, and rise time. Comparisons between devices were performed with the Kruskal-Wallis test with post hoc Mann-Whitney pairwise comparisons. Agreement was evaluated using Bland-Altman plots. Oxyhemoglobin measured with NIRO responded faster than the other NIRS technologies to changes in peripheral tissue oxygenation (20 vs. 27-40 s, p ≤ 0.01). When comparing INVOS with Foresight, oxygenation changes were prompter (upslope 311 [92-523]%/min vs. 114[65-199]%/min, p ≤ 0.01) and more pronounced (minimum value 36 [21-48] vs. 45 [40-51]%, p ≤ 0.01) with INVOS. Significant differences in tissue oxygen saturation measurements were observed, both within the same device as between different devices using the same measurement technology.

Cavitation Inception in Separated Flows.

DTIC Science & Technology

1981-12-01

measured data. Keller (1972, 1973) determined the nuclei population by using a single particle light scattering device (the sample volume was... computations of the average pressure coefficient. The amount of air dissolved in the water varied from 10 to 11 ppm ( molar ) and was measured with a Van Slyke...fluctuating pressures were also measured. .-The conditions for cavitation inception and desinence were determined and several holograms were recorded

Validation and use of the Finometer for blood pressure measurement in normal, hypertensive and pre-eclamptic pregnancy.

PubMed

Elvan-Taşpinar, Ayten; Uiterkamp, Leonore A; Sikkema, J Marko; Bots, Michiel L; Koomans, Hein A; Bruinse, Hein W; Franx, Arie

2003-11-01

Although a large variety of automated blood pressure devices are available, only some have been validated for use in clinical practice. The British Hypertension Society (BHS) recommends separate validation of automated devices in special subgroups, e.g. the elderly and pregnant women. The aim of this study was to compare the Finometer (FM) and the earlier validated SpaceLabs 90207 (SL) with standard auscultatory blood pressure measurements in normal, pre-eclamptic and hypertensive pregnancy, following the guidelines of the BHS and the Association for the Advancement of Medical Instrumentation (AAMI). The total study group consisted of 123 pregnant women, of whom were 54 normotensive, 31 pre-eclamptic and 38 hypertensive. Automated readings with the FM and SL were compared with auscultatory blood pressure measurements. Bland-Altman plots, BHS grades, mean pressure differences and 95% limits of agreement were used for analysis. Bland-Altman plots showed a wide scatter of the pressure differences between auscultatory and automated measurements. FM achieved BHS grades C/D, C/B, D/D and D/D in the total, normotensive, pre-eclamptic and hypertensive group, respectively. The AAMI criteria were only met for diastolic blood pressure in the normotensive group. For SL almost identical BHS grades and 95% limits of agreement as compared to our earlier study were found. The accuracy and precision of the Finometer are not sufficient for determination of absolute blood pressure levels in individual pregnant women. Our present findings on the SpaceLabs 90207 reconfirm our earlier results.

A novel interferometric characterization technique for 3D analyses at high pressures and temperatures

NASA Astrophysics Data System (ADS)

Roshanghias, Ali; Bardong, Jochen; Pulko, Jozef; Binder, Alfred

2018-04-01

Advanced optical measurement techniques are always of interest for the characterization of engineered surfaces. When pressure or temperature modules are also incorporated, these techniques will turn into robust and versatile methodologies for various applications such as performance monitoring of devices in service conditions. However, some microelectromechanical systems (MEMS) and MOEMS devices require performance monitoring at their final stage, i.e. enclosed or packaged. That necessitates measurements through a protective liquid, plastic, or glass, whereas the conventional objective lenses are not designed for such media. Correspondingly, in the current study, the development and tailoring of a 3D interferometer as a means for measuring the topography of reflective surfaces under transmissive media is sought. For topography measurements through glass, water and oil, compensation glass plates were designed and incorporated into the Michelson type interferometer objectives. Moreover, a customized chamber set-up featuring an optical access for the observation of the topographical changes at increasing pressure and temperature conditions was constructed and integrated into the apparatus. Conclusively, the in situ monitoring of the elastic deformation of sensing microstructures inside MEMS packages was achieved. These measurements were performed at a defined pressure (0–100 bar) and temperature (25 °C–180 °C).

Use of paravascular admittance waveforms to monitor relative change in arterial blood pressure

NASA Astrophysics Data System (ADS)

Zielinski, Todd M.; Hettrick, Doug; Cho, Yong

2010-04-01

Non-invasive methods to monitor ambulatory blood pressure often have limitations that can affect measurement accuracy and patient adherence [1]. Minimally invasive measurement of a relative blood pressure surrogate with an implantable device may provide a useful chronic diagnostic and monitoring tool. We assessed a technique that uses electrocardiogram and paravascular admittance waveform morphology analysis to one, measure a time duration (vascular tone index, VTI in milliseconds) change from the electrocardiogram R-wave to admittance waveform peak and two, measure the admittance waveform minimum, maximum and magnitude as indicators of change in arterial compliance/distensibility or pulse pressure secondary to change in afterload. Methods: Five anesthetized domestic pigs (32 ± 4.2 kg) were used to study the effects of phenylephrine (1-5 ug/kg/min) on femoral artery pressure and admittance waveform morphology measured with a quadrapolar electrode array catheter placed next to the femoral artery to assess the relative change in arterial compliance due to change in peripheral vascular tone. Results: Statistical difference was observed (p < 0.05) comparing baseline VTI to phenylephrine VTI (246 ± .05 ms to 320 ± .07 ms) and baseline admittance waveform maximum to phenylephrine admittance waveform maximum (0.0148 ± .002 siemens to 0.0151 ± .002 siemens). Conclusion: Chronic minimally invasive admittance measurement techniques that monitor relative change in blood pressure may be suitable for implantable devices to detect progression of cardiovascular disease such as hypertension.

Device and method for the measurement of gas permeability through membranes

DOEpatents

Agarwal, Pradeep K.; Ackerman, John; Borgialli, Ron; Hamann, Jerry; Muknahalliptna, Suresh

2006-08-08

A device for the measuring membrane permeability in electrical/electrochemical/photo-electrochemical fields is provided. The device is a permeation cell and a tube mounted within the cell. An electrode is mounted at one end of the tube. A membrane is mounted within the cell wherein a corona is discharged from the electrode in a general direction toward the membrane thereby generating heated hydrogen atoms adjacent the membrane. A method for measuring the effects of temperature and pressure on membrane permeability and selectivity is also provided.

Acoustic field characterization of the Duolith: measurements and modeling of a clinical shock wave therapy device.

PubMed

Perez, Camilo; Chen, Hong; Matula, Thomas J; Karzova, Maria; Khokhlova, Vera A

2013-08-01

Extracorporeal shock wave therapy (ESWT) uses acoustic pulses to treat certain musculoskeletal disorders. In this paper the acoustic field of a clinical portable ESWT device (Duolith SD1) was characterized. Field mapping was performed in water for two different standoffs of the electromagnetic head (15 or 30 mm) using a fiber optic probe hydrophone. Peak positive pressures at the focus ranged from 2 to 45 MPa, while peak negative pressures ranged from -2 to -11 MPa. Pulse rise times ranged from 8 to 500 ns; shock formation did not occur for any machine settings. The maximum standard deviation in peak pressure at the focus was 1.2%, indicating that the Duolith SD1 generates stable pulses. The results compare qualitatively, but not quantitatively with manufacturer specifications. Simulations were carried out for the short standoff by matching a Khokhlov-Zabolotskaya-Kuznetzov equation to the measured field at a plane near the source, and then propagating the wave outward. The results of modeling agree well with experimental data. The model was used to analyze the spatial structure of the peak pressures. Predictions from the model suggest that a true shock wave could be obtained in water if the initial pressure output of the device were doubled.

Acoustic field characterization of the Duolith: Measurements and modeling of a clinical shock wave therapy device

PubMed Central

Perez, Camilo; Chen, Hong; Matula, Thomas J.; Karzova, Maria; Khokhlova, Vera A.

2013-01-01

Extracorporeal shock wave therapy (ESWT) uses acoustic pulses to treat certain musculoskeletal disorders. In this paper the acoustic field of a clinical portable ESWT device (Duolith SD1) was characterized. Field mapping was performed in water for two different standoffs of the electromagnetic head (15 or 30 mm) using a fiber optic probe hydrophone. Peak positive pressures at the focus ranged from 2 to 45 MPa, while peak negative pressures ranged from −2 to −11 MPa. Pulse rise times ranged from 8 to 500 ns; shock formation did not occur for any machine settings. The maximum standard deviation in peak pressure at the focus was 1.2%, indicating that the Duolith SD1 generates stable pulses. The results compare qualitatively, but not quantitatively with manufacturer specifications. Simulations were carried out for the short standoff by matching a Khokhlov-Zabolotskaya-Kuznetzov equation to the measured field at a plane near the source, and then propagating the wave outward. The results of modeling agree well with experimental data. The model was used to analyze the spatial structure of the peak pressures. Predictions from the model suggest that a true shock wave could be obtained in water if the initial pressure output of the device were doubled. PMID:23927207

Assessment of an active industrial exoskeleton to aid dynamic lifting and lowering manual handling tasks.

PubMed

Huysamen, Kirsten; de Looze, Michiel; Bosch, Tim; Ortiz, Jesus; Toxiri, Stefano; O'Sullivan, Leonard W

2018-04-01

The aim of this study was to evaluate the effect of an industrial exoskeleton on muscle activity, perceived musculoskeletal effort, measured and perceived contact pressure at the trunk, thighs and shoulders, and subjective usability for simple sagittal plane lifting and lowering conditions. Twelve male participants lifted and lowered a box of 7.5 kg and 15 kg, respectively, from mid-shin height to waist height, five times, both with and without the exoskeleton. The device significantly reduced muscle activity of the Erector Spinae (12%-15%) and Biceps Femoris (5%). Ratings of perceived musculoskeletal effort in the trunk region were significantly less with the device (9.5%-11.4%). The measured contact pressure was highest on the trunk (91.7 kPa-93.8 kPa) and least on shoulders (47.6 kPa-51.7 kPa), whereas pressure was perceived highest on the thighs (35-44% of Max LPP). Six of the users rated the device usability as acceptable. The exoskeleton reduced musculoskeletal loading on the lower back and assisted with hip extensor torque during lifting and lowering. Contact pressures fell below the Pain Pressure Threshold. Perceived pressure was not exceptionally high, but sufficiently high to cause discomfort if used for long durations. Copyright © 2017 Elsevier Ltd. All rights reserved.

Accurate prediction of energy expenditure using a shoe-based activity monitor.

PubMed

Sazonova, Nadezhda; Browning, Raymond C; Sazonov, Edward

2011-07-01

The aim of this study was to develop and validate a method for predicting energy expenditure (EE) using a footwear-based system with integrated accelerometer and pressure sensors. We developed a footwear-based device with an embedded accelerometer and insole pressure sensors for the prediction of EE. The data from the device can be used to perform accurate recognition of major postures and activities and to estimate EE using the acceleration, pressure, and posture/activity classification information in a branched algorithm without the need for individual calibration. We measured EE via indirect calorimetry as 16 adults (body mass index=19-39 kg·m) performed various low- to moderate-intensity activities and compared measured versus predicted EE using several models based on the acceleration and pressure signals. Inclusion of pressure data resulted in better accuracy of EE prediction during static postures such as sitting and standing. The activity-based branched model that included predictors from accelerometer and pressure sensors (BACC-PS) achieved the lowest error (e.g., root mean squared error (RMSE)=0.69 METs) compared with the accelerometer-only-based branched model BACC (RMSE=0.77 METs) and nonbranched model (RMSE=0.94-0.99 METs). Comparison of EE prediction models using data from both legs versus models using data from a single leg indicates that only one shoe needs to be equipped with sensors. These results suggest that foot acceleration combined with insole pressure measurement, when used in an activity-specific branched model, can accurately estimate the EE associated with common daily postures and activities. The accuracy and unobtrusiveness of a footwear-based device may make it an effective physical activity monitoring tool.

Laboratory Connections. Gas Monitoring Transducers.

ERIC Educational Resources Information Center

Powers, Michael H.

1988-01-01

Discusses three types of sensors; pressure, gas detection, and relative humidity. Explains their use for laboratory measurements of gas pressure and detection of specific gaseous species. Shows diagrams of devices and circuits along with examples and applications including microcomputer interfacing. (RT)

Validation of the Beurer BM 44 upper arm blood pressure monitor for home measurement, according to the European Society of Hypertension International Protocol 2002.

PubMed

Lüders, Stephan; Krüger, Ralf; Zemmrich, Claudia; Forstner, Klaus; Sturm, Claus-Dieter; Bramlage, Peter

2012-12-01

The present study aimed to validate the automated upper arm blood pressure (BP) measuring device BM 44 for home BP monitoring according to the 2002 Protocol of the European Society of Hypertension. The most important new feature of the new device was an integrated 'WHO indicator', which categorizes the patient's individual result within the WHO recommendations for target BP by a coloured scale. Systolic and diastolic BPs were measured sequentially in 35 adult participants (16 men, 19 women) using a standard mercury y-tubed reference sphygmomanometer (two observers) and the BM 44 device (one supervisor). Ninety-nine pairs of comparisons were obtained from 15 participants in phase 1 and a further 18 participants in phase 2 of the validation study. The BM 44 device passed phase 1 of the validation study successfully with a number of absolute differences between device and observers of 5, 10 and 15 mmHg for at least 28 out of 25, 35 out of 35 and 40 out of 40 measurements, respectively. The device also achieved the targets for phases 2.1 and 2.2, with 23 and 26 participants having had at least two of three device-observers differences within 5 mmHg for systolic and diastolic BP, respectively. The Beurer BM 44 upper arm BP monitor has passed the International Protocol requirements, and hence can be recommended for home use in adults. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Validation of the A&D BP UA-651 device for home blood pressure measurement according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Benetti, Elisabetta; Fania, Claudio; Palatini, Paolo

2014-02-01

The objective of this study was to determine the accuracy of the A&D BP UA-651 device for home blood pressure (BP) measurement according to the International Protocol of the European Society of Hypertension. Device evaluation was carried out in 33 patients. The mean age of the patients was 48.3±15.5 years, the mean systolic BP was 138.3±24.9 mmHg (range 90-180), the mean diastolic BP was 88.3±13.8 mmHg (range 60-108), and the mean arm circumference was 28.6±3.4 cm (range 23-36). The protocol requirements were followed precisely. The device passed all requirements, fulfilling the standards of the protocol. On average, the device underestimated the systolic BP by 0.4±4.4 mmHg and diastolic BP by 1.3±3.5 mmHg. The device-observer discrepancies were unrelated to patients' clinical characteristics. These data show that the A&D BP UA-651 device fulfilled the requirements for validation by the International Protocol and can be recommended for clinical use in the adult population.

A catalogue of devices applicable to the measurement of boundary layers and wakes on flight vehicles

NASA Technical Reports Server (NTRS)

Miley, S. J.

1972-01-01

A literature search was conducted to assemble a catalog of devices and techniques which have possible application to boundary layer and wake measurements on flight vehicles. The indices used in the search were NACA, NASA STAR, IAA, USGRDR and Applied Science and Technology Index. The period covered was 1950 through 1970. The devices contained in the catalog were restricted to those that provided essentially direct measurement of velocities, pressures and shear stresses. Pertinent material was included in the catalog if it contained either an adequate description of a device and associated performance data or a presentation of applicable information on a particular measurement theory and/or technique. When available, illustrations showing the configuration of the device and test condition data were also included.

Obstructive sleep apnea devices for out-of-center (OOC) testing: technology evaluation.

PubMed

Collop, Nancy A; Tracy, Sharon L; Kapur, Vishesh; Mehra, Reena; Kuhlmann, David; Fleishman, Sam A; Ojile, Joseph M

2011-10-15

Guidance is needed to help clinicians decide which out-of-center (OOC) testing devices are appropriate for diagnosing obstructive sleep apnea (OSA). A new classification system that details the type of signals measured by these devices is presented. This proposed system categorizes OOC devices based on measurements of Sleep, Cardiovascular, Oximetry, Position, Effort, and Respiratory (SCOPER) parameters.Criteria for evaluating the devices are also presented, which were generated from chosen pre-test and post-test probabilities. These criteria state that in patients with a high pretest probability of having OSA, the OOC testing device has a positive likelihood ratio (LR+) of 5 or greater coinciding with an in-lab-polysomnography (PSG)-generated apnea hypopnea index (AHI) ≥ 5, and an adequate sensitivity (at least 0.825).Since oximetry is a mandatory signal for scoring AHI using PSG, devices that do not incorporate oximetry were excluded. English peer-reviewed literature on FDA-approved devices utilizing more than 1 signal was reviewed according to the above criteria for 6 questions. These questions specifically addressed the adequacy of different respiratory and effort sensors and combinations thereof to diagnose OSA. In summary, the literature is currently inadequate to state with confidence that a thermistor alone without any effort sensor is adequate to diagnose OSA; if a thermal sensing device is used as the only measure of respiration, 2 effort belts are required as part of the montage and piezoelectric belts are acceptable in this context; nasal pressure can be an adequate measurement of respiration with no effort measure with the caveat that this may be device specific; nasal pressure may be used in combination with either 2 piezoelectric or respiratory inductance plethysmographic (RIP) belts (but not 1 piezoelectric belt); and there is insufficient evidence to state that both nasal pressure and thermistor are required to adequately diagnose OSA. With respect to alternative devices for diagnosing OSA, the data indicate that peripheral arterial tonometry (PAT) devices are adequate for the proposed use; the device based on cardiac signals shows promise, but more study is required as it has not been tested in the home setting; for the device based on end-tidal CO(2) (ETCO(2)), it appears to be adequate for a hospital population; and for devices utilizing acoustic signals, the data are insufficient to determine whether the use of acoustic signals with other signals as a substitute for airflow is adequate to diagnose OSA.Standardized research is needed on OOC devices that report LR+ at the appropriate AHI (≥ 5) and scored according to the recommended definitions, while using appropriate research reporting and methodology to minimize bias.

Real-Time Optical Fuel-to-Air Ratio Sensor for Gas Turbine Combustors

NASA Technical Reports Server (NTRS)

Nguyen, Quang-Viet; Mongia, Rajiv K.; Dibble, Robert W.

1999-01-01

The measurement of the temporal distribution of fuel in gas turbine combustors is important in considering pollution, combustion efficiency and combustor dynamics and acoustics. Much of the previous work in measuring fuel distributions in gas turbine combustors has focused on the spatial aspect of the distribution. The temporal aspect however, has often been overlooked, even though it is just as important. In part, this is due to the challenges of applying real-time diagnostic techniques in a high pressure and high temperature environment. A simple and low-cost instrument that non-intrusively measures the real-time fuel-to-air ratio (FAR) in a gas turbine combustor has been developed. The device uses a dual wavelength laser absorption technique to measure the concentration of most hydrocarbon fuels such as jet fuel, methane, propane, etc. The device can be configured to use fiber optics to measure the local FAR inside a high pressure test rig without the need for windows. Alternatively, the device can readily be used in test rigs that have existing windows without modifications. An initial application of this instrument was to obtain time-resolved measurements of the FAR in the premixer of a lean premixed prevaporized (LPP) combustor at inlet air pressures and temperatures as high as 17 atm at 800 K, with liquid JP-8 as the fuel. Results will be presented that quantitatively show the transient nature of the local FAR inside a LPP gas turbine combustor at actual operating conditions. The high speed (kHz) time resolution of this device, combined with a rugged fiber optic delivery system, should enable the realization of a flight capable active-feedback and control system for the abatement of noise and pollutant emissions in the future. Other applications that require an in-situ and time-resolved measurement of fuel vapor concentrations should also find this device to be of use.

Intraocular pressure control of a novel glaucoma drainage device - in vitro and in vivo studies

PubMed Central

Cui, Li-Jun; Li, Di-Chen; Liu, Jian; Zhang, Lei; Xing, Yao

2017-01-01

AIM To evaluate the intraocular pressure (IOP) control of an artificial trabeculum drainage system (ATDS), a newly designed glaucoma drainage device, and postoperative complications in normal rabbit eyes. METHODS Pressure drops in air and fluid of 30 ATDS were measured after being connected to a closed manometric system. Twenty of them were then chosen and implanted randomly into the eyes of 20 rabbits. Postoperative slit-lamp, gonioscopic examination and IOP measurements were recorded periodically. Ultrasound biomicroscopy and B-scan ultrasonography were also used to observe the complications. Eyes were enucleated on day 60. RESULTS Pressure drops of 4.6-9.4 mm Hg were obtained at physiological aqueous flow rates in the tests in vitro. The average postoperative IOP of the experimental eyes (11.6-12.8 mm Hg) was lower than the controls significantly (P<0.05) at each time point. Complications of hemorrhage (n=1), cellulosic exudation (two cases) and local iris congestion (two cases) were observed. The lumina of the devices were devoid of obstructions in all specimens examined and a thin fibrous capsule was found around the endplate. CONCLUSION ATDS reduce IOP effectively. However, further studies on the structure are needed to reduce complications. PMID:28944192

Intrathoracic pressure regulation during cardiopulmonary resuscitation: a feasibility case-series.

PubMed

Segal, Nicolas; Parquette, Brent; Ziehr, Jonathon; Yannopoulos, Demetris; Lindstrom, David

2013-04-01

Intrathoracic pressure regulation (IPR) is a novel, noninvasive therapy intended to increase cardiac output and blood pressure in hypotensive states by generating a negative end expiratory pressure of -12 cm H2O between positive pressure ventilations. In this first feasibility case-series, we tested the hypothesis that IPR improves End tidal (ET) CO2 during cardiopulmonary resuscitation (CPR). ETCO2 was used as a surrogate measure for circulation. All patients were treated initially with manual CPR and an impedance threshold device (ITD). When IPR-trained medics arrived on scene the ITD was removed and an IPR device (CirQLATOR™) was attached to the patient's advanced airway (intervention group). The IPR device lowered airway pressures to -9 mmHg after each positive pressure ventilation for the duration of the expiratory phase. ETCO2, was measured using a capnometer incorporated into the defibrillator system (LifePak™). Values are expressed as mean ± SEM. Results were compared using paired and unpaired Student's t test. p values of <0.05 were considered statistically significant. ETCO2 values in 11 patients in the case series were compared pre and during IPR therapy and also compared to 74 patients in the control group not treated with the new IPR device. ETCO2 values increased from an average of 21 ± 1 mmHg immediately before IPR application to an average value of 32 ± 5 mmHg and to a maximum value of 45 ± 5mmHg during IPR treatment (p<0.001). In the control group ETCO2 values did not change significantly. Return of spontaneous circulation (ROSC) rates were 46% (34/74) with standard CPR and ITD versus 73% (8/11) with standard CPR and the IPR device (p<0.001). ETCO2 levels and ROSC rates were significantly higher in the study intervention group. These findings demonstrate that during CPR circulation may be significantly augmented by generation of a negative end expiratory pressure between each breath. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Simultaneous validation of the SunTech CT40 automated blood pressure measurement device by the 1993 British Hypertension Society protocol and the Association for the Advancement of Medical Instrumentation/International Organization for Standardization 81060-2: 2013 standard.

PubMed

Polo Friz, Hernan; Punzi, Veronica; Petri, Francesco; Orlandi, Riccardo; Maggiolini, Daniele; Polo Friz, Melisa; Primitz, Laura; Vighi, Giuseppe

2017-10-01

This study aimed to perform a simultaneous, third-party, independent validation of the oscillometric SunTech CT40 device for blood pressure (BP) measurement, according to the 1993 protocol of the British Hypertension Society and the standard of the Association for the Advancement of Medical Instrumentation (AAMI)/the International Organization for Standardization (ISO) 81060-2:2013. Patient recruitment, study procedures, and data analysis followed the recommendations stated by the protocols. The study was approved by the institutional review board. A total of 94 participants were included, 52 (55.3%) women, mean±SD age: 63.1±18.0 years, mean±SD arm circumference: 35.0±9.0 cm. The average of observers' entry BPs was 146.9±37.2 mmHg for systolic blood pressure (SBP) and 82.2±22.1 mmHg for diastolic blood pressure (DBP). Differences between the standard measurement and the test device within 5, 10, and 15 mmHg, for the better observer, were 79.4, 96.5, and 100.0% for SBP and 82.6, 97.5, and 100.0% for DBP, respectively. The mean±SD differences between the readings obtained using the test device and those obtained by the observers (AAMI/ISO 81060-2:2013 standard criterion 1) were 0.3±5.0 mmHg (SBP) and -0.8±4.3 mmHg (DBP), and the mean±SD differences between average of reference readings and average of test device readings in each patient (criterion 2) were 0.3±3.9 and -0.8±3.5 mmHg for SBP and DBP, respectively. The CT40 BP device achieved A/A grade of the British Hypertension Society protocol and fulfilled the requirements (criteria 1 and 2) of the AAMI/ISO standard. CT40 can be recommended for BP measurement in adults.

Baroreflex activation therapy lowers arterial pressure without apparent stimulation of the carotid bodies.

PubMed

Alnima, Teba; Goedhart, Emilie J B M; Seelen, Randy; van der Grinten, Chris P M; de Leeuw, Peter W; Kroon, Abraham A

2015-06-01

Carotid baroreflex activation therapy produces a sustained fall in blood pressure in patients with resistant hypertension. Because the activation electrodes are implanted at the level of the carotid sinus, it is conceivable that the nearby located carotid body chemoreceptors are stimulated as well. Physiological stimulation of the carotid chemoreceptors not only stimulates respiration but also increases sympathetic activity, which may counteract the effects of baroreflex activation. The aim of this exploratory study is to investigate whether there is concomitant carotid chemoreflex activation during baroreflex activation therapy. Fifteen participants with the Rheos system were included in this single-center study. At arrival at the clinic, the device was switched off for 2 hours while patients were at rest. Subsequently, the device was switched on at 6 electric settings of high and low frequencies and amplitudes. Respiration and blood pressure measurements were performed during all device activation settings. Multilevel statistical models were adjusted for age, sex, body mass index, antihypertensive therapeutic index, sleep apnea, coronary artery disease, systolic blood pressure, and heart rate. There was no change in end-tidal carbon dioxide, partial pressure of carbon dioxide, breath duration, and breathing frequency during any of the electric settings with the device. Nevertheless, mean arterial pressure showed a highly significant decrease during electric activation (P<0.001). Carotid baroreflex activation therapy using the Rheos system did not stimulate respiration at several electric device activation energies, which suggests that there is no appreciable coactivation of carotid body chemoreceptors during device therapy. © 2015 American Heart Association, Inc.

Fast response air-to-fuel ratio measurements using a novel device based on a wide band lambda sensor

NASA Astrophysics Data System (ADS)

Regitz, S.; Collings, N.

2008-07-01

A crucial parameter influencing the formation of pollutant gases in internal combustion engines is the air-to-fuel ratio (AFR). During transients on gasoline and diesel engines, significant AFR excursions from target values can occur, but cycle-by-cycle AFR resolution, which is helpful in understanding the origin of deviations, is difficult to achieve with existing hardware. This is because current electrochemical devices such as universal exhaust gas oxygen (UEGO) sensors have a time constant of 50-100 ms, depending on the engine running conditions. This paper describes the development of a fast reacting device based on a wide band lambda sensor which has a maximum time constant of ~20 ms and enables cyclic AFR measurements for engine speeds of up to ~4000 rpm. The design incorporates a controlled sensor environment which results in insensitivity to sample temperature and pressure. In order to guide the development process, a computational model was developed to predict the effect of pressure and temperature on the diffusion mechanism. Investigations regarding the sensor output and response were carried out, and sensitivities to temperature and pressure are examined. Finally, engine measurements are presented.

Comparison of noninvasive assessments of central blood pressure using general transfer function and late systolic shoulder of the radial pressure wave.

PubMed

Wohlfahrt, Peter; Krajcoviechová, Alena; Seidlerová, Jitka; Mayer, Otto; Filipovsky, Jan; Cífková, Renata

2014-02-01

Central systolic blood pressure (cSBP) can be derived by the general transfer function of the radial pressure wave, as used in the SphygmoCor device, or by regression equation from directly measured late systolic shoulder of the radial pressure wave (pSBP2), as used in the Omron HEM-9000AI device. The aim of this study was to compare the SphygmoCor estimates of cSBP with 2 estimates of cSBP provided by the Omron HEM-9000AI (cSBP, pSBP2) in a large cohort of the white population. In 391 patients aged 52.3±13.5 years (46% men) from the Czech post-MONICA Study, cSBP was measured using the SphygmoCor and Omron HEM-9000AI devices in random order. Omron cSBP and pSBP2 were perfectly correlated (r = 1.0; P < 0.0001). There was a strong correlation (r = 0.97; P < 0.0001) between Omron and SphygmoCor cSBP estimates, but Omron estimate was 13.1±4.7mm Hg higher than SphygmoCor cSBP. On the other hand, Omron pSBP2 strongly correlated with SphygmoCor cSBP (r = 0.97; P < 0.0001) and was 1.7±4.2mm Hg lower than SphygmoCor cSBP. In multivariable analysis, anthropometric and cardiovascular risk factors explained only 10% of the variance of the cSBP difference between devices while explaining 52% of the systolic blood pressure amplification variance. Estimation of cSBP based on the late systolic shoulder of the radial wave provides a comparable accuracy with the validated general transfer function. When comparing Omron HEM-9000AI and SphygmoCor estimates of cSBP, Omron pSBP2 should be used. The difference between both devices in cSBP may be explained by differences in calibration.

The Icare HOME (TA022) Study: Performance of an Intraocular Pressure Measuring Device for Self-Tonometry by Glaucoma Patients.

PubMed

Mudie, Lucy I; LaBarre, Sophie; Varadaraj, Varshini; Karakus, Sezen; Onnela, Jouni; Munoz, Beatriz; Friedman, David S

2016-08-01

To evaluate the Icare HOME (TA022) device (Icare Oy, Vanda, Finland) for use by glaucoma patients for self-tonometry. Prospective performance evaluation of a medical device. One hundred eighty-nine participants with glaucoma or suspected glaucoma were recruited from the Wilmer Eye Institute, Baltimore, Maryland, between July 2014 and April 2015. Participants had standardized training and had to be able use the Icare HOME device independently. Subjects also had to be able to obtain the first intraocular pressure (IOP) measurement within 5 mmHg of Goldmann applanation tonometry (GAT). Those certified obtained 3 IOP measures using the HOME device, and these were compared with Icare TA01i and GAT IOP measurements. The agreement between Icare HOME and reference tonometers was used to assess precision. The intraclass correlation coefficient was used to assess within-patient reliability for the HOME device. Eighteen of 189 recruited patients were ineligible to take part in the study. Forty-four of 171 patients (25.7%) started but failed to complete the study: 7 stopped because of time concerns, 10 of 171 patients (6%) stopped because of difficulty using the device during certification, and 27 of 171 patients (16%) failed to be certified based on IOP. The HOME and GAT measurements agreed within 5 mmHg in 116 of 127 participants (91.3%); 2 participants (1.6%) had a difference of more than 7 mmHg. The mean difference between the Icare HOME and GAT measurements was -0.33 mmHg (standard deviation, 3.11 mmHg). The overall intraclass correlation coefficient for the HOME device was 0.92 (95% confidence interval, 0.89-0.95). Not all participants could learn how to use the Icare HOME device, but for those who could, most were able to obtain measurements similar to those obtained by GAT. The Icare HOME device is safe and reliable for self-tonometry, but nearly 1 in 6 individuals may fail to certify in use of the device based on large differences in IOP when comparing GAT with the Icare HOME measurements. The device has the potential to address an unmet need by providing more frequent IOP measurements in a patient's day to day life. Copyright © 2016 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

A comparison of measured and predicted test flow in an expansion tube with air and oxygen test gases

NASA Technical Reports Server (NTRS)

Aaggard, K. V.; Goad, W. K.

1975-01-01

Simultaneous time-resolved measurements of temperature, density, pitot pressure, and wall pressure in both air and O2 test gases were obtained in the Langley pilot model expansion tube. These tests show nonequilibrium chemical and vibrational relaxation significantly affect the test-flow condition. The use of an electromagnetic device to preopen the secondary diaphragm before the arrival of the primary shock wave resulted in an improvement in the agreement between the measured pitot pressure and the value inferred from measured density and interface velocity. Boundary-layer splitter plates used to reduce the wall boundary layer show that this disagreement in the measured and inferred pitot pressures is not a result of boundary-layer effects.

Device and method for measuring multi-phase fluid flow in a conduit using an elbow flow meter

DOEpatents

Ortiz, Marcos G.; Boucher, Timothy J.

1997-01-01

A system for measuring fluid flow in a conduit. The system utilizes pressure transducers disposed generally in line upstream and downstream of the flow of fluid in a bend in the conduit. Data from the pressure transducers is transmitted to a microprocessor or computer. The pressure differential measured by the pressure transducers is then used to calculate the fluid flow rate in the conduit. Control signals may then be generated by the microprocessor or computer to control flow, total fluid dispersed, (in, for example, an irrigation system), area of dispersal or other desired effect based on the fluid flow in the conduit.

Bench evaluation: three face-shield CPR barrier devices.

PubMed

Simmons, M; Deao, D; Moon, L; Peters, K; Cavanaugh, S

1995-06-01

Due to the fear of disease transmission, the practice of mouth-to-mouth (M-M) rescue breathing is rarely performed; to address this concern, many types of CPR barrier devices have been developed. These include bag-valve-mask devices, mouth-to-mask devices, and face shields (FS). The purpose of this study was to measure the volumes delivered during mouth-to-face shield (M-FS) breathing, to measure the back pressure and calculate the resistance to flow through their 1-way valves, and to test for backward leak of gas through the valves. Three FS brands were evaluated: Kiss of Life (KOL), MicroSHIELD (Micro) and Res-Cue Key (RCK). Volume delivered during M-M and M-FS breathing was evaluated by 10 rescuers who used the devices while performing rescue breathing on a CPR mannequin. Back pressure was measured and resistance calculated by directing airflow through the 1-way valves. Backward leak was evaluated by measuring the O2 concentration at the rescuer side of the valve while 100% O2 was directed toward the patient side of the valve. Differences among the brands were evaluated using analysis of variance. The mean (SD) values for volumes in L were: M-M 1.00 (0.25), Micro 0.77 (0.20), RCK 0.64 (0.10), and KOL 0.24 (0.11). Mean values for back pressure in cm H2O at 50 L/min were Micro 16.7 (1.29), KOL 7.22 (0.13), and RCK 2.15 (0.16). Significant backward leak only occurred with RCK. Not one of the FSs tested met all of the requirements suggested by the American Heart Association and by the International Standards Organization.

Gas flow meter and method for measuring gas flow rate

DOEpatents

Robertson, Eric P.

2006-08-01

A gas flow rate meter includes an upstream line and two chambers having substantially equal, fixed volumes. An adjustable valve may direct the gas flow through the upstream line to either of the two chambers. A pressure monitoring device may be configured to prompt valve adjustments, directing the gas flow to an alternate chamber each time a pre-set pressure in the upstream line is reached. A method of measuring the gas flow rate measures the time required for the pressure in the upstream line to reach the pre-set pressure. The volume of the chamber and upstream line are known and fixed, thus the time required for the increase in pressure may be used to determine the flow rate of the gas. Another method of measuring the gas flow rate uses two pressure measurements of a fixed volume, taken at different times, to determine the flow rate of the gas.

Flexible Piezoelectric-Induced Pressure Sensors for Static Measurements Based on Nanowires/Graphene Heterostructures.

PubMed

Chen, Zefeng; Wang, Zhao; Li, Xinming; Lin, Yuxuan; Luo, Ningqi; Long, Mingzhu; Zhao, Ni; Xu, Jian-Bin

2017-05-23

The piezoelectric effect is widely applied in pressure sensors for the detection of dynamic signals. However, these piezoelectric-induced pressure sensors have challenges in measuring static signals that are based on the transient flow of electrons in an external load as driven by the piezopotential arisen from dynamic stress. Here, we present a pressure sensor with nanowires/graphene heterostructures for static measurements based on the synergistic mechanisms between strain-induced polarization charges in piezoelectric nanowires and the caused change of carrier scattering in graphene. Compared to the conventional piezoelectric nanowire or graphene pressure sensors, this sensor is capable of measuring static pressures with a sensitivity of up to 9.4 × 10 -3 kPa -1 and a fast response time down to 5-7 ms. This demonstration of pressure sensors shows great potential in the applications of electronic skin and wearable devices.

Validation of the SEJOY BP-1307 upper-arm blood pressure monitor for home blood pressure monitoring according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Lei, Lei; Chen, Yi; Chen, Qi; Li, Yan; Wang, Ji-Guang

2017-12-01

The present study aimed to evaluate the accuracy of the automated oscillometric upper-arm blood pressure monitor SEJOY BP-1307 (also called JOYTECH DBP-1307) for home blood pressure monitoring according to the International Protocol of the European Society of Hypertension revision 2010. Systolic and diastolic blood pressures were sequentially measured in 33 adult Chinese individuals (13 women, 45.1 years of mean age) using a mercury sphygmomanometer (two observers) and the SEJOY BP-1307 device (one supervisor). Ninety-nine pairs of comparisons were obtained from 33 participants for judgments in two parts with three grading phases. The average±SD of the device-observer differences was 0.2±4.1 and -1.7±4.7 mmHg for systolic and diastolic blood pressure, respectively. The SEJOY BP-1307 device achieved the criteria in both part 1 and part 2 of the validation study. The SEJOY upper-arm blood pressure monitor BP-1307 has passed the requirements of the International Protocol revision 2010, and hence can be recommended for home use in adults.

Servo-controlled pneumatic pressure oscillator for respiratory impedance measurements and high-frequency ventilation.

PubMed

Kaczka, David W; Lutchen, Kenneth R

2004-04-01

The ability to provide forced oscillatory excitation of the respiratory system can be useful in mechanical impedance measurements as well as high frequency ventilation (HFV). Experimental systems currently used for generating forced oscillations are limited in their ability to provide high amplitude flows or maintain the respiratory system at a constant mean pressure during excitation. This paper presents the design and implementation of a pneumatic pressure oscillator based on a proportional solenoid valve. The device is capable of providing forced oscillatory excitations to the respiratory system over a bandwidth suitable for mechanical impedance measurements and HVF. It delivers high amplitude flows (> 1.4 l/s) and utilizes a servo-control mechanism to maintain a load at a fixed mean pressure during simultaneous oscillation. Under open-loop conditions, the device exhibited a static hysteresis of approximately 7%, while its dynamic magnitude and phase responses were flat out to 10 Hz. Broad-band measurement of total harmonic distortion was approximately 19%. Under closed-loop conditions, the oscillator was able to maintain a mechanical test load at both positive and negative mean pressures during oscillatory excitations from 0.1 to 10.0 Hz. Impedance of the test load agreed closely with theoretical predictions. We conclude that this servo-controlled oscillator can be a useful tool for respiratory impedance measurements as well as HFV.

High resolution gas volume change sensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dirckx, Joris J. J.; Aernouts, Jef E. F.; Aerts, Johan R. M.

2007-05-15

Changes of gas quantity in a system can be measured either by measuring pressure changes or by measuring volume changes. As sensitive pressure sensors are readily available, pressure change is the commonly used technique. In many physiologic systems, however, buildup of pressure influences the gas exchange mechanisms, thus changing the gas quantity change rate. If one wants to study the gas flow in or out of a biological gas pocket, measurements need to be done at constant pressure. In this article we present a highly sensitive sensor for quantitative measurements of gas volume change at constant pressure. The sensor ismore » based on optical detection of the movement of a droplet of fluid enclosed in a capillary. The device is easy to use and delivers gas volume data at a rate of more than 15 measurements/s and a resolution better than 0.06 {mu}l. At the onset of a gas quantity change the sensor shows a small pressure artifact of less than 15 Pa, and at constant change rates the pressure artifact is smaller than 10 Pa or 0.01% of ambient pressure.« less

Device Stores and Discharges Metered Fluid

NASA Technical Reports Server (NTRS)

Hooper, S. L.; Setzer, D.

1983-01-01

Hand-held container accepts measured amount of liquid from pressurized supply. Supply pressure drives spring-loaded piston that stores enough mechanical energy to discharge measured liquid into another container. Original application of container was to rehydrate sterilized pre-packaged food in zerogravity environment of space vehicles. Possible terrestrial applicatios include dispensing of toxic fluids or metering of fluids for household, commercial or laboratory uses.

A comparative study of MOEM pressure sensors using MZI, DC, and racetrack resonator IO structures

NASA Astrophysics Data System (ADS)

Selvarajan, A.; Pattnaik, Prasant Kumar; Badrinarayana, T.; Srinivas, T.

2006-03-01

In recent years micro-electro-mechanical system (MEMS) sensors have drawn considerable attention due to their attraction in terms of miniaturization, batch fabrication and ease of integration with the required electronics circuitry. Micro-opto-electro-mechanical (MOEM) devices and systems, based on the principles of integrated optics and micromachining technology on silicon have immense potential for sensor applications. Employing optical techniques have important advantages such as functionality, large bandwidth and higher sensitivity. Pressure sensing is currently the most lucrative market for solid-state micro sensors. Pressure sensing using micromachined structures utilize the changes induced in either the resistive or capacitive properties of the electro-mechanical structure by the impressed pressure. Integrated optical pressure sensors can utilize the changes to the amplitude, phase, refractive index profile, optical path length, or polarization of the lightwave by the external pressure. In this paper we compare the performance characteristics of three types of MOEM pressure sensors based on Mach-Zehnder Interferometer (MZI), Directional Coupler (DC) and racetrack resonator (RR) integrated optical geometries. The first two configurations measure the pressure changes through a change in optical intensity while the third one measures the same in terms of frequency or wavelength change. The analysis of each sensors has been carried out in terms of mechanical and optical models and their interrelationship through optomechanical coupling. For a typical diaphragm of size 2mm × 1mm × 20 μm, normalized pressure sensitivity of 18.35 μW/mW/kPa, 29.37 μW/mW/kPa and 2.26 pm/kPa in case of MZI, DC and RR devices have been obtained respectively. The noise performance of these devices are also presented.

New diesel injection nozzle flow measuring device

NASA Astrophysics Data System (ADS)

Marčič, Milan

2000-04-01

A new measuring device has been developed for diesel injection nozzle testing, allowing measuring of the steady flow through injection nozzle and the injection rate. It can be best applied for measuring the low and high injection rates of the pintle and single hole nozzle. In steady flow measuring the fuel pressure at the inlet of the injection nozzle is 400 bar. The sensor of the measuring device measures the fuel charge, resulting from fuel rubbing in the fuel injection system, as well as from the temperature gradient in the sensor electrode. The electric charge is led to the charge amplifier, where it is converted into electric current and amplified. The amplifier can be used also to measure the mean injection rate value.

49 CFR 232.403 - Design standards for one-way end-of-train devices.

Code of Federal Regulations, 2010 CFR

2010-10-01

... valve to prevent explosion from a high pressure air leak inside the rear unit. (c) Reporting rate... shall be capable of determining the brake pipe pressure on the rear car and transmitting that... measuring the brake pipe pressure on the rear car with an accuracy of ±3 pounds per square inch (psig) and...

Engineering studies of vectorcardiographs in blood pressure measuring systems, appendix 2

NASA Technical Reports Server (NTRS)

Mark, R. G.

1975-01-01

The development of a cardiovascular monitoring system to noninvasively monitor the blood pressure and heart rate using pulse wave velocity was described. The following topics were covered: (1) pulse wave velocity as a measure of arterial blood pressure, (2) diastolic blood pressure and pulse wave velocity in humans, (3) transducer development for blood pressure measuring device, and (4) cardiovascular monitoring system. It was found, in experiments on dogs, that the pulse wave velocity is linearly related to diastolic blood pressure over a wide range of blood pressure and in the presence of many physiological perturbations. A similar relationship was observed in normal, young human males over a moderate range of pressures. Past methods for monitoring blood pressure and a new method based on pulse wave velocity determination were described. Two systems were tested: a Doppler ultrasonic transducer and a photoelectric plethysmograph. A cardiovascular monitoring system was described, including operating instructions.

Comparison of 4-Layer Bandages and an Adaptive Compression Therapy Device on Intended Pressure Delivery.

PubMed

Mayrovitz, Harvey N; Partsch, Hugo; Vanscheidt, Wolfgang

2015-01-01

To characterize and compare interface pressure profiles of an adaptive compression therapy (ACT) device and a traditional 4-layer bandage (4LB) system. A prospective, randomized, open-label, 1-arm, active controlled study. The sample comprised 12 healthy volunteers. Subjects wore both devices for 8 hours on 3 consecutive days. Treatments were randomized to left and right legs. One clinician performed all applications and was experienced in the clinical use of both devices. Pressures were measured in seated and standing positions at the lower, mid, and upper calf immediately post application and after 1, 4, and 8 hours. Pressures achieved with the ACT were closer to targeted 40/30/20 mmHg graduated pressure values and were significantly less than the 4LB for corresponding sites/postures (P < .001). In the seated position, initial interface pressures (mean ± SD) for the ACT were 36.9 ± 4.9, 30.5 ± 4.5, and 21.0 ± 3.6 mmHg. Corresponding interface pressures for the 4LB were 52.5 ± 8.4, 57.5 ± 10.3, and 53.5 ± 12.9 mmHg. In the standing position, initial interface pressures for the ACT were 40.7 ± 4.8, 35.6 ± 4.5, and 21.1 ± 4.6 compared to 54.6 ± 12.5, 64.4 ± 10.9, and 53.7 ± 14.3 for the 4LB. At 1, 4, and 8 hours after application, the 4LB showed a significant progressive decline in interface pressure in both seated and standing positions (P < .001). Conversely, the ACT did not decrease over time and there was a slight but significant increase for lower and mid-calf sites in the seated position (P < .001). The ACT device provided more consistent interface pressures than the 4LB and the pressures achieved were consistent with contemporary venous ulcer therapy standards.

A Low-Power and Portable Biomedical Device for Respiratory Monitoring with a Stable Power Source

PubMed Central

Yang, Jiachen; Chen, Bobo; Zhou, Jianxiong; Lv, Zhihan

2015-01-01

Continuous respiratory monitoring is an important tool for clinical monitoring. Associated with the development of biomedical technology, it has become more and more important, especially in the measuring of gas flow and CO2 concentration, which can reflect the status of the patient. In this paper, a new type of biomedical device is presented, which uses low-power sensors with a piezoresistive silicon differential pressure sensor to measure gas flow and with a pyroelectric sensor to measure CO2 concentration simultaneously. For the portability of the biomedical device, the sensors and low-power measurement circuits are integrated together, and the airway tube also needs to be miniaturized. Circuits are designed to ensure the stability of the power source and to filter out the existing noise. Modulation technology is used to eliminate the fluctuations at the trough of the waveform of the CO2 concentration signal. Statistical analysis with the coefficient of variation was performed to find out the optimal driving voltage of the pressure transducer. Through targeted experiments, the biomedical device showed a high accuracy, with a measuring precision of 0.23 mmHg, and it worked continuously and stably, thus realizing the real-time monitoring of the status of patients. PMID:26270665

Non-Invasive Measurement of Intracranial Pressure Pulsation using Ultrasound

NASA Technical Reports Server (NTRS)

Ueno, Toshiaki; Ballard, R. E.; Yost, W. T.; Hargens, A. R.

1997-01-01

Exposure to microgravity causes a cephalad fluid shift which may elevate intracranial pressure (ICP). Elevation in ICP may affect cerebral hemodynamics in astronauts during space flight. ICP is, however, a difficult parameter to measure due to the invasiveness of currently available techniques. We already reported our development of a non-invasive ultrasound device for measurement of ICP. We recently modified the device so that we might reproducibly estimate ICP changes in association with cardiac cycles. In the first experiment, we measured changes in cranial distance with the ultrasound device in cadavera while changing ICP by infusing saline into the lateral ventricle. In the second experiment, we measured changes in cranial distance in five healthy volunteers while placing them in 60 deg, 30 deg head-up tilt, supine, and 10 deg head-down tilt position. In the cadaver study, fast Fourier transformation revealed that cranial pulsation is clearly associated with ICP pulsation. The ratio of cranial distance and ICP pulsation is 1.3microns/mmHg. In the tilting study, the magnitudes of cranial pulsation are linearly correlated to tilt angles (r=0.87). The ultrasound device has sufficient sensitivity to detect cranial pulsation in association with cardiac cycles. By analyzing the magnitude of cranial pulsation, estimates of ICP during space flight are possible.

A microfluidic needle for sampling and delivery of chemical signals by segmented flows

NASA Astrophysics Data System (ADS)

Feng, Shilun; Liu, Guozhen; Jiang, Lianmei; Zhu, Yonggang; Goldys, Ewa M.; Inglis, David W.

2017-10-01

We have developed a microfluidic needle-like device that can extract and deliver nanoliter samples. The device consists of a T-junction to form segmented flows, parallel channels to and from the needle tip, and seven hydrophilic capillaries at the tip that form a phase-extraction region. The main microchannel is hydrophobic and carries segmented flows of water-in-oil. The hydrophilic capillaries transport the aqueous phase with a nearly zero pressure gradient but require a pressure gradient of 19 kPa for mineral oil to invade and flow through. Using this device, we demonstrate the delivery of nanoliter droplets and demonstrate sampling through the formation of droplets at the tip of our device. During sampling, we recorded the fluorescence intensities of the droplets formed at the tip while varying the concentration of dye outside the tip. We measured a chemical signal response time of approximately 3 s. The linear relationship between the recorded fluorescence intensity of samples and the external dye concentration (10-40 μg/ml) indicates that this device is capable of performing quantitative, real-time measurements of rapidly varying chemical signals.

Pressure-Relief Features of Fixed and Autotitrating Continuous Positive Airway Pressure May Impair Their Efficacy: Evaluation with a Respiratory Bench Model

PubMed Central

Zhu, Kaixian; Aouf, Sami; Roisman, Gabriel; Escourrou, Pierre

2016-01-01

Study Objectives: Pressure-relief features are aimed at improving the patient's comfort during continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea. The objective of this study was to determine the effect of these therapy features on fixed CPAP and autotitrating CPAP (APAP) treatment efficacy. Methods: Seven pressure-relief features applied by three CPAP devices were included in our study (Remstar Auto: C-Flex 3, C-Flex+ 3, A-Flex 3, P-Flex; AirSense 10: EPR 3; Prisma 20A: SoftPAP 2 and 3). In fixed CPAP, the devices were subjected to a 10-min bench-simulated obstructive apnea sequence (initial apnea-hypopnea index, AHI = 60/h) with and without pressure-relief features. In APAP, the sequence was lengthened to 4.2 h (initial AHI = 58.6/h). The residual AHI and mean/median pressure were compared with and without pressure-relief features. Results: Compared to conventional CPAP, where pressure was adjusted to be just sufficient to control the simulated obstructive events, C-Flex+ 3, P-Flex, and EPR 3 failed to normalize the breathing flow and did not reduce the AHI. The mean pressures with the three features, respectively, were 1.8, 2.6, and 2.6 cmH2O lower than the conventional CPAP. Compared to conventional APAP, similar levels of control were observed with pressure-relief features, apart from P-Flex where the delivered mean pressure was lower and residual AHI greater. The device-reported mean/median pressures in APAP with A-Flex 3, P-Flex, EPR 3, and SoftPAP 3 were higher than that measured on the bench. Conclusions: Pressure-relief features may attenuate CPAP efficacy if not adjusted for at the time of their introduction. In clinical practice, efficacy can be ensured by increasing the therapeutic pressure delivered by fixed CPAP or by enabling the pressure-relief features prior to initial pressure titration. Device-reported pressures in APAP devices with pressure relief activated may overstate delivered pressures. Citation: Zhu K, Aouf S, Roisman G, Escourrou P. Pressure-relief features of fixed and autotitrating continuous positive airway pressure may impair their efficacy: evaluation with a respiratory bench model. J Clin Sleep Med 2016;12(3):385–392. PMID:26564383

A review of the latest guidelines for NIBP device validation.

PubMed

Alpert, Bruce S; Quinn, David E; Friedman, Bruce A

2013-12-01

The current ISO Standard is accepted as the National Standard in almost every industrialized nation. An overview of the most recently adopted standards is provided. Standards writing groups including the Advancement of Medical Instrumentation Sphygmomanometer Committee and ISO JWG7 are working to expand standardized evaluation methods to include the evaluation of devices intended for use in environments where motion artifact is common. An Association for the Advancement of Medical Instrumentation task group on noninvasive blood pressure measurement in the presence of motion artifact has published a technical information report containing research and standardized methods for the evaluation of blood pressure device performance in the presence of motion artifact.

An exploratory study on differences in cumulative plantar tissue stress between healing and non-healing plantar neuropathic diabetic foot ulcers.

PubMed

van Netten, Jaap J; van Baal, Jeff G; Bril, Adriaan; Wissink, Marieke; Bus, Sicco A

2018-03-01

Mechanical stress is important in causing and healing plantar diabetic foot ulcers, but almost always studied as peak pressure only. Measuring cumulative plantar tissue stress combines plantar pressure and ambulatory activity, and better defines the load on ulcers. Our aim was to explore differences in cumulative plantar tissue stress between people with healing and non-healing plantar diabetic foot ulcers. We analyzed a subgroup of 31 patients from a randomized clinical trial, treated with a removable offloading device for their plantar diabetic forefoot ulcer. We measured in-device dynamic plantar pressure and daily stride count to calculate cumulative plantar tissue stress at the ulcer location and associated this with ulcer healing and ulcer surface area reduction at four weeks (Student's t and chi-square test for significance, Cohen's d for effect size). In 12 weeks, 68% (n = 21) of the ulcers healed and 32% (n = 10) did not. No statistically significant differences were found for cumulative plantar tissue stress, plantar pressure or ambulatory activity between people with healed and not-healed ulcers. Cumulative plantar tissue stress was 25% lower for people with healed ulcers (155 vs. 207 MPa·s/day; P = 0.71; Effect size: d = 0.29). Post-hoc analyses in the 27 patients who self-reported to be adherent to wearing the device showed that cumulative plantar tissue stress was 49% lower for those who reached ≥75% ulcer surface area reduction at four weeks (140 vs. 275 MPa·s/day; P = 0.09; d = 0.76); smaller differences and effect sizes were found for peak pressure (24%), peak pressure-time integral (30%) and ambulatory activity (26%); (P-value range: 0.14-0.97; Cohen's d range: 0.14-0.70). Measuring cumulative plantar tissue stress may provide insight beyond that obtained from plantar pressure or ambulatory activity alone, with regard to diabetic foot ulcer healing using removable offloading devices. These explorative findings provide baseline data for further studies on this relevant topic. Copyright © 2018 Elsevier Ltd. All rights reserved.

Liquid sinusoidal pressure measurement by laser interferometry based on the refractive index of water.

PubMed

Yang, Jun; Fan, Shangchun; Li, Cheng; Guo, Zhanshe; Li, Bo; Shi, Bo

2016-12-01

A new method with laser interferometry is used to enhance the traceability for sinusoidal pressure calibration in water. The laser vibrometer measures the dynamic pressure based on the acousto-optic effect. The relation of the refractive index of water and the optical path length with the pressure's change is built based on the Lorentz-Lorenz equation, and the conversion coefficients are tested by static calibration in situ. A device with a piezoelectric transducer and resonant pressure pipe with water is set up to generate sinusoidal pressure up to 20 kHz. With the conversion coefficients, the reference sinusoidal pressure is measured by the laser interferometer for pressure sensors' dynamic calibration. The experiment results show that under 10 kHz, the measurement results between the laser vibrometer and a piezoelectric sensor are in basic agreement and indicate that this new method and its measurement system are feasible in sinusoidal pressure calibration. Some disturbing components including small amplitude, temperature change, pressure maldistribution, and glass windows' vibration are also analyzed, especially for the dynamic calibrations above 10 kHz.

Multimode fiber tip Fabry-Perot cavity for highly sensitive pressure measurement.

PubMed

Chen, W P; Wang, D N; Xu, Ben; Zhao, C L; Chen, H F

2017-03-23

We demonstrate an optical Fabry-Perot interferometer fiber tip sensor based on an etched end of multimode fiber filled with ultraviolet adhesive. The fiber device is miniature (with diameter of less than 60 μm), robust and low cost, in a convenient reflection mode of operation, and has a very high gas pressure sensitivity of -40.94 nm/MPa, a large temperature sensitivity of 213 pm/°C within the range from 55 to 85 °C, and a relatively low temperature cross-sensitivity of 5.2 kPa/°C. This device has a high potential in monitoring environment of high pressure.

Validation of the Pangao PG-800A36 automatic wrist blood pressure monitor according to the European Society of Hypertension and the British Hypertension Society protocols.

PubMed

Zhao, Hairong; Qiao, Weichang; Zhang, Rui; Cui, Peng; Hou, Fanglin; Zhang, Wenli

2018-02-01

The aim of this study was to validate the PG-800A36 automatic wrist blood pressure monitor according to the European Society of Hypertension International Protocol (ESH-IP) revision 2010 and the British Hypertension Society (BHS) protocols. A total of 33 participants were initially included on the basis of the ESH-IP, followed by examination of 85 participants according to the BHS protocol. The procedures and analysis methods of the protocols were followed precisely with left arm/wrist sequential measurements by two trained observers using a mercury sphygmomanometer and one supervisor using the device. The device passed the ESH-IP with an average difference of 1.45±6.46 mmHg for systolic blood pressure and 1.25±5.10 mmHg for diastolic blood pressure. Furthermore, the A/A grade of the BHS protocol was achieved with an average difference of 1.84±6.94 mmHg for systolic blood pressure and 1.15±6.49 mmHg for diastolic blood pressure, and thus, the device also fulfilled the requirements of the Association for the Advancement of Medical Instrumentation. The Pangao PG-800A36 passed the requirements of the ESH-IP revision 2010 and achieved the A/A grade of the BHS protocol, which can be recommended for self-measurement in the general population.

Obstructive Sleep Apnea Devices for Out-Of-Center (OOC) Testing: Technology Evaluation

PubMed Central

Collop, Nancy A.; Tracy, Sharon L.; Kapur, Vishesh; Mehra, Reena; Kuhlmann, David; Fleishman, Sam A.; Ojile, Joseph M.

2011-01-01

Guidance is needed to help clinicians decide which out-of-center (OOC) testing devices are appropriate for diagnosing obstructive sleep apnea (OSA). A new classification system that details the type of signals measured by these devices is presented. This proposed system categorizes OOC devices based on measurements of Sleep, Cardiovascular, Oximetry, Position, Effort, and Respiratory (SCOPER) parameters. Criteria for evaluating the devices are also presented, which were generated from chosen pre-test and post-test probabilities. These criteria state that in patients with a high pretest probability of having OSA, the OOC testing device has a positive likelihood ratio (LR+) of 5 or greater coinciding with an in-lab-polysomnography (PSG)-generated apnea hypopnea index (AHI) ≥ 5, and an adequate sensitivity (at least 0.825). Since oximetry is a mandatory signal for scoring AHI using PSG, devices that do not incorporate oximetry were excluded. English peer-reviewed literature on FDA-approved devices utilizing more than 1 signal was reviewed according to the above criteria for 6 questions. These questions specifically addressed the adequacy of different respiratory and effort sensors and combinations thereof to diagnose OSA. In summary, the literature is currently inadequate to state with confidence that a thermistor alone without any effort sensor is adequate to diagnose OSA; if a thermal sensing device is used as the only measure of respiration, 2 effort belts are required as part of the montage and piezoelectric belts are acceptable in this context; nasal pressure can be an adequate measurement of respiration with no effort measure with the caveat that this may be device specific; nasal pressure may be used in combination with either 2 piezoelectric or respiratory inductance plethysmographic (RIP) belts (but not 1 piezoelectric belt); and there is insufficient evidence to state that both nasal pressure and thermistor are required to adequately diagnose OSA. With respect to alternative devices for diagnosing OSA, the data indicate that peripheral arterial tonometry (PAT) devices are adequate for the proposed use; the device based on cardiac signals shows promise, but more study is required as it has not been tested in the home setting; for the device based on end-tidal CO2 (ETCO2), it appears to be adequate for a hospital population; and for devices utilizing acoustic signals, the data are insufficient to determine whether the use of acoustic signals with other signals as a substitute for airflow is adequate to diagnose OSA. Standardized research is needed on OOC devices that report LR+ at the appropriate AHI (≥ 5) and scored according to the recommended definitions, while using appropriate research reporting and methodology to minimize bias. Citation: Collop NA; Tracy SL; Kapur V; Mehra R; Kuhlmann D; Fleishman SA; Ojile JM. Obstructive sleep apnea devices for out-of-center (OOC) testing: technology evaluation. J Clin Sleep Med 2011;7(5):531-548. PMID:22003351

Pulse Oximeter Derived Blood Pressure Measurement in Patients With a Continuous Flow Left Ventricular Assist Device.

PubMed

Hellman, Yaron; Malik, Adnan S; Lane, Kathleen A; Shen, Changyu; Wang, I-Wen; Wozniak, Thomas C; Hashmi, Zubair A; Munson, Sarah D; Pickrell, Jeanette; Caccamo, Marco A; Gradus-Pizlo, Irmina; Hadi, Azam

2017-05-01

Currently, blood pressure (BP) measurement is obtained noninvasively in patients with continuous flow left ventricular assist device (LVAD) by placing a Doppler probe over the brachial or radial artery with inflation and deflation of a manual BP cuff. We hypothesized that replacing the Doppler probe with a finger-based pulse oximeter can yield BP measurements similar to the Doppler derived mean arterial pressure (MAP). We conducted a prospective study consisting of patients with contemporary continuous flow LVADs. In a small pilot phase I inpatient study, we compared direct arterial line measurements with an automated blood pressure (ABP) cuff, Doppler and pulse oximeter derived MAP. Our main phase II study included LVAD outpatients with a comparison between Doppler, ABP, and pulse oximeter derived MAP. A total of five phase I and 36 phase II patients were recruited during February-June 2014. In phase I, the average MAP measured by pulse oximeter was closer to arterial line MAP rather than Doppler (P = 0.06) or ABP (P < 0.01). In phase II, pulse oximeter MAP (96.6 mm Hg) was significantly closer to Doppler MAP (96.5 mm Hg) when compared to ABP (82.1 mm Hg) (P = 0.0001). Pulse oximeter derived blood pressure measurement may be as reliable as Doppler in patients with continuous flow LVADs. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Effect of a Patient-Repositioning Device in an Intensive Care Unit On Hospital-Acquired Pressure Injury Occurences and Cost: A Before-After Study.

PubMed

Edger, Melinda

The principal aim of this study was to determine the hospital-acquired pressure injury (HAPI) rate before and after introduction of a repositioning device, measure staff-perceived level of exertion with device use, and assess return on investment. 1 group, before-and-after study. The sample comprised 717 patients cared for in a 17-bed intensive care unit. The study setting was the neonatal intensive care unit at Bon Secours Maryview Medical Center located in the mid-Atlantic United States (Portsmouth, Virginia). A safe patient-handling intervention was implemented as part of a quality improvement initiative. The effect of this system was measured using several outcome measures: (1) HAPI occurrences on the sacral area and buttocks, (2) perceived effort of use by staff, and (3) cost analysis. We used the validated Borg Scale to measure perceived exertion that was ranked on a scale from 6 to 20, where higher scores indicate greater exertion. Cost comparisons were completed before and after introduction of the patient-repositioning system. Cost analysis was determined using internal dollar amounts calculated for each stage of pressure injury. The return on investment was calculated by comparing the cost of HAPIs and the product after the intervention with the costs of HAPIs before the intervention. Analysis revealed a statistically significant reduction in HAPI occurrence from 1.3% to 0% (P = .004) when baseline manual repositioning (standard of care) was compared with use of the repositioning system. Caregivers reported significantly less exertion when using the repositioning device as compared with standard of care repositioning (P < .001). The return on investment was estimated to be $16,911. Use of a repositioning device resulted in significantly reduced HAPIs. Perceived exertion for repositioning the patient with a repositioning device was significantly less than repositioning with standard of care. A cost analysis estimated a return on investment as a result of the intervention on HAPI prevention.

New weight-handling device for commercial oil pressure balances

NASA Astrophysics Data System (ADS)

Woo, S. Y.; Choi, I. M.; Kim, B. S.

2005-12-01

This paper presents a new device to automatically handle a large number of weights for the calibration of a pressure gauge. This newly invented weight-handling device is made for use in conjunction with a commercial oil pressure balance. Although the pressure balance is essential as a calibration tool, its use has been generally tedious and labour intensive for a long time. In particular, the process of loading a different combination of weights on the top of a piston requires repetitious manual handling for every new measurement. This inevitably leaves the operator fatigued, and sometimes causes damage to the weights due to careless handling. The newly invented automatic weight-handling device can eliminate such tedious, error-prone and wear-inducing manual weight manipulation. The device consists of a stepping motor, a drive belt, a solenoid valve, three weight-lifting assemblies and three linear-motion guide assemblies. The weight-lifting assembly is composed of a pneumatic actuator, a solid-state switch and a metal finger. It has many advantages compared with the commercial automatic weight-handling device. Firstly, it is not necessary to lift all the weights off the piston in the weight selection process, as it is in the case of the commercial device. Thus it can prevent a permanent deformation of the weight carrier. Secondly, this new device can handle a larger number of weights than the commercial one. This is because the new device adopts a different method in retaining the remaining weights in place. Another advantage of this new device is that there is no possibility of the fingers touching the surface of the weights due to the oscillation of weights. Moreover it uses the general technology of a stepping motor, and is also made up of components that are easily obtainable in the market, thereby being very economical.

Wave energy absorption by a submerged air bag connected to a rigid float.

PubMed

Kurniawan, A; Chaplin, J R; Hann, M R; Greaves, D M; Farley, F J M

2017-04-01

A new wave energy device features a submerged ballasted air bag connected at the top to a rigid float. Under wave action, the bag expands and contracts, creating a reciprocating air flow through a turbine between the bag and another volume housed within the float. Laboratory measurements are generally in good agreement with numerical predictions. Both show that the trajectory of possible combinations of pressure and elevation at which the device is in static equilibrium takes the shape of an S. This means that statically the device can have three different draughts, and correspondingly three different bag shapes, for the same pressure. The behaviour in waves depends on where the mean pressure-elevation condition is on the static trajectory. The captured power is highest for a mean condition on the middle section.

Wave energy absorption by a submerged air bag connected to a rigid float

PubMed Central

Chaplin, J. R.; Hann, M. R.; Greaves, D. M.; Farley, F. J. M.

2017-01-01

A new wave energy device features a submerged ballasted air bag connected at the top to a rigid float. Under wave action, the bag expands and contracts, creating a reciprocating air flow through a turbine between the bag and another volume housed within the float. Laboratory measurements are generally in good agreement with numerical predictions. Both show that the trajectory of possible combinations of pressure and elevation at which the device is in static equilibrium takes the shape of an S. This means that statically the device can have three different draughts, and correspondingly three different bag shapes, for the same pressure. The behaviour in waves depends on where the mean pressure-elevation condition is on the static trajectory. The captured power is highest for a mean condition on the middle section. PMID:28484330

Quasi-Isentropic Compressibility of Deuterium at a Pressure of 12 TPa

NASA Astrophysics Data System (ADS)

Mochalov, M. A.; Il'kaev, R. I.; Fortov, V. E.; Mikhailov, A. L.; Arinin, V. A.; Blikov, A. O.; Komrakov, V. A.; Maksimkin, I. P.; Ogorodnikov, V. A.; Ryzhkov, A. V.

2018-04-01

An experimental result for the quasi-isentropic compressibility of a strongly nonideal deuterium plasma compressed in a spherical device by the pressure P = 11400 GPa (114 Mbar) to the density ρ ≈ 10g/cm3 has been reported. The characteristics of the experimental device, diagnostic methods, and experimental results have been described. The trajectory of motion of metallic shells compressing a deuterium plasma has been recorded using intense pulsed sources of X rays with the boundary energy of electrons up to 60 MeV. The deuterium plasma density ρ ≈ 10g/cm3 has been determined from the measured radius of the shell at the time of its "stop." The pressure of the compressed plasma has been determined from gas-dynamic calculations taking into account the real characteristics of the experimental device.

Wave energy absorption by a submerged air bag connected to a rigid float

NASA Astrophysics Data System (ADS)

Kurniawan, A.; Chaplin, J. R.; Hann, M. R.; Greaves, D. M.; Farley, F. J. M.

2017-04-01

A new wave energy device features a submerged ballasted air bag connected at the top to a rigid float. Under wave action, the bag expands and contracts, creating a reciprocating air flow through a turbine between the bag and another volume housed within the float. Laboratory measurements are generally in good agreement with numerical predictions. Both show that the trajectory of possible combinations of pressure and elevation at which the device is in static equilibrium takes the shape of an S. This means that statically the device can have three different draughts, and correspondingly three different bag shapes, for the same pressure. The behaviour in waves depends on where the mean pressure-elevation condition is on the static trajectory. The captured power is highest for a mean condition on the middle section.

Improvement of a sensor unit for wrist blood pressure monitoring system

NASA Astrophysics Data System (ADS)

Koo, Sangjun; Kwon, Jongwon; Park, Yongman; Ayuzenara, Odgerel; Kim, Hiesik

2007-12-01

A blood pressure sensor unit for ubiquitous healthcare monitoring was newly developed. The digital wrist band-type blood pressure devices for home are popular already in the market. It is useful for checking blood pressure level at home and control of hypertension. Especially, it is very essential home device to check the health condition of blood circulation disease. Nowadays many product types are available. But the measurement of blood pressure is not accurate enough compared with the mechanical type. It needs to be upgraded to assure the precise health data enough to use in the hospital. The structure, feature and output signal of capacitor type pressure sensors are analyzed. An improved design of capacitor sensor is suggested. It shows more precise health data after use on a wrist band type health unit. They can be applied for remote u-health medical service.

Fractional Ablative Laser Followed by Transdermal Acoustic Pressure Wave Device to Enhance the Drug Delivery of Aminolevulinic Acid: In Vivo Fluorescence Microscopy Study.

PubMed

Waibel, Jill S; Rudnick, Ashley; Nousari, Carlos; Bhanusali, Dhaval G

2016-01-01

Topical drug delivery is the foundation of all dermatological therapy. Laser-assisted drug delivery (LAD) using fractional ablative laser is an evolving modality that may allow for a greater precise depth of penetration by existing topical medications, as well as more efficient transcutaneous delivery of large drug molecules. Additional studies need to be performed using energy-driven methods that may enhance drug delivery in a synergistic manner. Processes such as iontophoresis, electroporation, sonophoresis, and the use of photomechanical waves aid in penetration. This study evaluated in vivo if there is increased efficacy of fractional CO2 ablative laser with immediate acoustic pressure wave device. Five patients were treated and biopsied at 4 treatment sites: 1) topically applied aminolevulinic acid (ALA) alone; 2) fractional ablative CO2 laser and topical ALA alone; 3) fractional ablative CO2 laser and transdermal acoustic pressure wave device delivery system; and 4) topical ALA with transdermal delivery system. The comparison of the difference in the magnitude of diffusion with both lateral spread of ALA and depth diffusion of ALA was measured by fluorescence microscopy. For fractional ablative CO2 laser, ALA, and transdermal acoustic pressure wave device, the protoporphyrin IX lateral fluorescence was 0.024 mm on average vs 0.0084 mm for fractional ablative CO2 laser and ALA alone. The diffusion for the acoustic pressure wave device was an order of magnitude greater. We found that our combined approach of fractional ablative CO2 laser paired with the transdermal acoustic pressure wave device increased the depth of penetration of ALA.

In vitro performance and principles of anti-siphoning devices.

PubMed

Freimann, Florian Baptist; Kimura, Takaoki; Stockhammer, Florian; Schulz, Matthias; Rohde, Veit; Thomale, Ulrich-Wilhelm

2014-11-01

Anti-siphon devices (ASDs) of various working principles were developed to overcome overdrainage-related complications associated with ventriculoperitoneal shunting. We aimed to provide comparative data on the pressure and flow characteristics of six different types of ASDs (gravity-assisted, membrane-controlled, and flow-regulated) in order to achieve a better understanding of these devices and their potential clinical application. We analyzed three gravity-dependent ASDs (ShuntAssistant [SA], Miethke; Gravity Compensating Accessory [GCA], Integra; SiphonX [SX], Sophysa), two membrane-controlled ASDs (Anti-Siphon Device [IASD], Integra; Delta Chamber [DC], Medtronic), and one flow-regulated ASD (SiphonGuard [SG], Codman). Defined pressure conditions within a simulated shunt system were generated (differential pressure 10-80 cmH2O), and the specific flow and pressure characteristics were measured. In addition, the gravity-dependent ASDs were measured in defined spatial positions (0-90°). The flow characteristics of the three gravity-assisted ASDs were largely dependent upon differential pressure and on their spatial position. All three devices were able to reduce the siphoning effect, but each to a different extent (flow at inflow pressure: 10 cmH2O, siphoning -20 cmH2O at 0°/90°: SA, 7.1 ± 1.2*/2.3 ±  0.5* ml/min; GCA, 10.5 ± 0.8/3.4 ± 0.4* ml/min; SX, 9.5 ± 1.2*/4.7 ± 1.9* ml/min, compared to control, 11.1 ± 0.4 ml/min [*p < 0.05]). The flow characteristics of the remaining ASDs were primarily dependent upon the inflow pressure effect (flow at 10 cmH2O, siphoning 0 cmH2O/ siphoning -20cmH2O: DC, 2.6 ± 0.1/ 4 ± 0.3* ml/min; IASD, 2.5 ± 0.2/ 0.8 ± 0.4* ml/min; SG, 0.8 ± 0.2*/ 0.2 ± 0.1* ml/min [*p < 0.05 vs. control, respectively]). The tested ASDs were able to control the siphoning effect within a simulated shunt system to differing degrees. Future comparative trials are needed to determine the type of device that is superior for clinical application.

Touch-mode capacitive pressure sensor with graphene-polymer heterostructure membrane

NASA Astrophysics Data System (ADS)

Berger, Christian; Phillips, Rory; Pasternak, Iwona; Sobieski, Jan; Strupinski, Wlodek; Vijayaraghavan, Aravind

2018-01-01

We describe the fabrication and characterisation of a touch-mode capacitive pressure sensor (TMCPS) with a robust design that comprises a graphene-polymer heterostructure film, laminated onto the silicon dioxide surface of a silicon wafer, incorporating a SU-8 spacer grid structure. The spacer grid structure allows the flexible graphene-polymer film to be partially suspended above the substrate, such that a pressure on the membrane results in a reproducible deflection, even after exposing the membrane to pressures over 10 times the operating range. Sensors show reproducible pressure transduction in water submersion at varying depths under static and dynamic loading. The measured capacitance change in response to pressure is in good agreement with an analytical model of clamped plates in touch mode. The device shows a pressure sensitivity of 27.1 +/- 0.5 fF Pa-1 over a pressure range of 0.5 kPa-8.5 kPa. In addition, we demonstrate the operation of this device as a force-touch sensor in air.

IN VITRO COMPARISON OF MAXIMUM PRESSURE DEVELOPED BY IRRIGATION SYSTEMS IN A KIDNEY MODEL.

PubMed

Proietti, Silvia; Dragos, Laurian; Somani, Bhaskar K; Butticè, Salvatore; Talso, Michele; Emiliani, Esteban; Baghdadi, Mohammed; Giusti, Guido; Traxer, Olivier

2017-04-05

To evaluate in vitro the maximum pressure generated in an artificial kidney model when people of different levels of strengths used various irrigation systems. Fifteen people were enrolled and divided in 3 groups based on their strengths. Individual strength was evaluated according to the maximum pressure each participant was able to achieve using an Encore™ Inflator. The irrigation systems evaluated were: T-FlowTM Dual Port, HilineTM, continuous flow single action pumping system (SAPSTM) with the system close and open, Irri-flo IITM, a simple 60-ml syringe and PeditrolTM . Each irrigation system was connected to URF-V2 ureteroscope, which was inserted into an artificial kidney model. Each participant was asked to produce the maximum pressure possible with every irrigation device. Pressure was measured with the working channel (WC) empty, with a laser fiber and a basket inside. The highest pressure was achieved with the 60 ml-syringe system and the lowest with SAPS continuous version system (with continuous irrigation open), compared to the other irrigation devices (p< 0.0001). Irrespective of the irrigation system, there was a significant difference in the pressure between the WC empty and when occupied with the laser fiber or the basket inside it (p<0.0001). The stratification between the groups showed that the most powerful group could produce the highest pressure in the kidney model with all the irrigation devices in almost any situation. The exception to this was the T-Flow system, which was the only device where no statistical differences were detected among these groups. The use of irrigation systems can often generate excessive pressure in an artificial kidney model, especially with an unoccupied WC of the ureteroscope. Depending on the strength of force applied, very high pressure can be generated by most irrigation devices irrespective of whether the scope is occupied or not.

Design and validation of the Grip-ball for measurement of hand grip strength.

PubMed

Jaber, Rana; Hewson, David J; Duchêne, Jacques

2012-11-01

The Grip-ball is a new dynamometer used to evaluate grip strength, as well as for use in home-based rehabilitation of the hand and forearm. The Grip-ball consists of pressure and temperature sensors and an electronic wireless communication system contained in an airtight ball. That can be inflated to different pressures. The device has advantages over standard dynamometers in that it looks like a simple ball, and can wirelessly communicate via Bluetooth to any compatible receiver, thus have potential to be used for clinical assessment and rehabilitation in a remote setting. The reliability and reproducibility of the device were assessed for the pressure sensor itself, as well as the relationship between the force applied and the pressure measured by the Grip-ball. The initial validation was performed using the pressure sensor without the ball in order to confirm the accuracy of the sensor used. A second validation study was conducted using the Grip-ball rather than just its sensor to examine the relationship between the pressure measured inside the ball and force applied. The results showed that there is a very good correlation (r=0.997, p<0.05) between the pressure measured by the Grip-ball sensor and that measured by a Vigorimeter, thus confirming the reliability of the sensor used in the Grip-ball. A quadratic regression equation was calculated in order to predict the force applied based on the pressure measured inside the ball, and the initial pressure to which the ball was inflated (R(2)=0.97, standard error 10.9N). Such a finding compares favourably with the variability inherent in Jamar recordings, thus indicating that the Grip-ball could be used to assess grip force. An industrial version of the Grip-ball, which is currently under development, will be able to be used for the entire range of grip force in the population. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

Using an extreme bony prominence anatomical model to examine the influence of bed sheet materials and bed making methods on the distribution of pressure on the support surface.

PubMed

Iuchi, Terumi; Nakajima, Yukari; Fukuda, Moriyoshi; Matsuo, Junko; Okamoto, Hiroyuki; Sanada, Hiromi; Sugama, Junko

2014-05-01

Bed sheets generate high surface tension across the support surface and increase pressure to the body through a process known as the hammock effect. Using an anatomical model and a loading device characterized by extreme bony prominences, the present study compared pressure distributions on support surfaces across different bed making methods and bed sheet materials to determine the factors that influence pressure distribution. The model was placed on a pressure mapping system (CONFORMat; NITTA Corp., Osaka, Japan), and interface pressure was measured. Bed sheet elasticity and friction between the support surface and the bed sheets were also measured. For maximum interface pressure, the relative values of the following methods were higher than those of the control method, which did not use any bed sheets: cotton sheets with hospital corners (1.28, p = 0.02), polyester with no corners (1.29, p = 0.01), cotton with no corners (1.31, p = 0.003), and fitted polyester sheets (1.35, p = 0.002). Stepwise multiple regression analysis indicated that maximum interface pressure was negatively correlated with bed sheet elasticity (R(2) = 0.74). A statistically significant negative correlation was observed between maximum interface pressure and immersion depth, which was measured using the loading device (r = -0.40 and p = 0.04). We found that several combinations of bed making methods and bed sheet materials induced maximum interface pressures greater than those observed for the control method. Bed sheet materials influenced maximum interface pressure, and bed sheet elasticity was particularly important in reducing maximum interface pressure. Copyright © 2014 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

Experimental flow studies in glaucoma drainage device development.

PubMed

2001-10-01

(I) To examine whether small holes produced by 248 nm excimer laser ablation in a polymer substrate could consistently produce a pressure drop in the desired target range (5-15 mm Hg) at physiological aqueous flow rates for use as an internal flow restrictor in a glaucoma drainage device, and (ii) to investigate whether external leakage could be reduced in comparison with conventional tube and plate glaucoma drainage devices by redesigning the exterior cross sectional shape of the portion contained within the sclerocorneal tunnel. Single holes with target diameters of 10 microm, 15 microm, 20 microm, and 25 microm were drilled using a 248 nm excimer laser in sample discs (n=6 at each diameter) punched from a 75 microm thick polyimide sheet. Sample discs were tested in a flow rig designed to measure the pressure drop across the discs. Using filtered, degassed water at a flow rate of 1.4 microl/min repeated flow measurements were taken (n=6) for each disc. After flow testing, all discs were imaged using a scanning electron microscope and the dimensions of each hole were derived using image analysis software. In the external leakage study, corneoscleral buttons (n=13) were prepared from cadaver pig eyes and mounted on an artificial anterior chamber infused with Tyrode solution. After the pressure had stabilised, standard occluded silicone tube implants were inserted through 23 gauge needle stab incisions at the limbus. These were compared against prototype PMMA implants with a novel shape profile inserted through 1.15 mm width microvitreoretinal (MVR) stab incisions at the limbus. The infusion rate was maintained and a second pressure measurement was taken when the pressure had stabilised. The difference between the first and second pressure measurement was then compared, as an index of external leakage. Ablated tubes were found to have a near perfect circular outline on both the entry and exit side. The observed pressure drops across the ablated sample discs at each target diameter were as follows: 10 microm, mean 25.66 (SD 4.9) mm Hg; 15 microm, 6.7 (1.15); 20 microm, 1.66 (1.07); and 25 microm, <0.1 mm Hg. A strong correlation was observed between observed pressure drops and those predicted by Poiseuille's formula (R(2) =0.996). Target ablations of 15 microm diameter produced tubes that consistently achieved a pressure drop within the desired range (5-15 mm Hg). In the external leakage study, preinsertion pressures (mm Hg; mean (SD)) were 19.00 (4.3) (conventional method) and 20.00 (3.9) (new technique with PMMA prototypes). Post-insertion pressures were significantly reduced (10.40 (7.7); p<0.01) for the conventional technique and were essentially unchanged for the new technique (18.80 (4.9); p>0.1). It was shown that it is possible, in principle, to control the dimensions of a manufactured tubular lumen in a glaucoma drainage device accurately enough to provide consistent protection from hypotony in the early period after glaucoma filtration surgery. By redesigning the external profile of glaucoma drainage device and incision technique, it was also shown that it is possible to eliminate uncontrolled external leakage.

A tethering system for direct measurement of cardiovascular function in the caged baboon

NASA Technical Reports Server (NTRS)

Byrd, L. D.

1979-01-01

A device suitable for the continuous measurement of physiological activity in large, conscious monkeys has permitted the direct recording of systemic arterial blood pressure and heart rate in caged baboons. The device comprises a lightweight fiberglass backpack, retained in place on the baboon by a thoracic elastic band and shoulder straps, and a flexible stainless steel tether connecting the pack to an electrocannular slip-ring in the top center of the baboon's cage. A chronically indwelling arterial catheter inserted retrograde into the abdominal aorta via the internal iliac artery and connected to a small pressure transducer on the pack provides direct measurement of blood pressure and heart rate. Body fluids can be sampled or drugs administered via an indwelling catheter in the inferior vena cava. Electrical and fluid connections between the fiberglass pack and recording and infusion equipment located outside the cage pass through the flexible tether and remain protected from the subject. The reliability of the tethering system has been demonstrated in physiological, pharmacological, and behavioral experiments with baboons.

Electron density measurement of non-equilibrium atmospheric pressure plasma using dispersion interferometer

NASA Astrophysics Data System (ADS)

Yoshimura, Shinji; Kasahara, Hiroshi; Akiyama, Tsuyoshi

2017-10-01

Medical applications of non-equilibrium atmospheric plasmas have recently been attracting a great deal of attention, where many types of plasma sources have been developed to meet the purposes. For example, plasma-activated medium (PAM), which is now being studied for cancer treatment, has been produced by irradiating non-equilibrium atmospheric pressure plasma with ultrahigh electron density to a culture medium. Meanwhile, in order to measure electron density in magnetic confinement plasmas, a CO2 laser dispersion interferometer has been developed and installed on the Large Helical Device (LHD) at the National Institute for Fusion Science, Japan. The dispersion interferometer has advantages that the measurement is insensitive to mechanical vibrations and changes in neutral gas density. Taking advantage of these properties, we applied the dispersion interferometer to electron density diagnostics of atmospheric pressure plasmas produced by the NU-Global HUMAP-WSAP-50 device, which is used for producing PAM. This study was supported by the Grant of Joint Research by the National Institutes of Natural Sciences (NINS).

Design of affordable and ruggedized biomedical devices using virtual instrumentation.

PubMed

Mathern, Ryan Michael; Schopman, Sarah; Kalchthaler, Kyle; Mehta, Khanjan; Butler, Peter

2013-05-01

Abstract This paper presents the designs of four low-cost and ruggedized biomedical devices, including a blood pressure monitor, thermometer, weighing scale and spirometer, designed for the East African context. The design constraints included a mass-production price point of $10, accuracy and precision comparable to commercial devices and ruggedness to function effectively in the harsh environment of East Africa. The blood pressure device, thermometer and weighing scale were field-tested in Kenya and each recorded data within 6% error of the measurements from commercial devices and withstood the adverse climate and rough handling. The spirometer functioned according to specifications, but a re-design is needed to improve operability and usability by patients. This article demonstrates the feasibility of designing and commercializing virtual instrumentation-based biomedical devices in resource-constrained environments through context-driven design. The next steps for the devices include designing them such that they can be more easily manufactured, use standardized materials, are easily calibrated in the field and have more user-friendly software programs that can be updated remotely.

Measurement of lower leg compression in vivo: recommendations for the performance of measurements of interface pressure and stiffness: consensus statement.

PubMed

Partsch, Hugo; Clark, Michael; Bassez, Sophie; Benigni, Jean-Patrick; Becker, Francis; Blazek, Vladimir; Caprini, Joseph; Cornu-Thénard, André; Hafner, Jürg; Flour, Mieke; Jünger, Michael; Moffatt, Christine; Neumann, Martino

2006-02-01

Interface pressure and stiffness characterizing the elastic properties of the material are the parameters determining the dosage of compression treatment and should therefore be measured in future clinical trials. To provide some recommendations regarding the use of suitable methods for this indication. This article was formulated based on the results of an international consensus meeting between a group of medical experts and representatives from the industry held in January 2005 in Vienna, Austria. Proposals are made concerning methods for measuring the interface pressure and for assessing the stiffness of a compression device in an individual patient. In vivo measurement of interface pressure is encouraged when clinical and experimental outcomes of compression treatment are to be evaluated.

[Invasive arterial blood pressure measurement using an aneroid pressure system in cattle].

PubMed

Mosing, M; Franz, S; Iff, I; Schwendenwein, I

2009-06-01

The aim of this study was to compare the results of invasive arterial blood pressure measurement using an electronic pressure transducer (EPT) or an aneroid pressure system (APS) in cattle. A catheter was placed in the auricular artery of 11 adult cattle and connected to a pressure transducer via pressure line. The aneroid system was connected to the same catheter using a three-way stop-cock in the pressure line. On five occasions three consecutive measurements were performed with the APS. The mean blood pressure values of the EPT were recorded before each individual measurement. Values from each device were compared using Passing and Bablok regression of agreement and a Bland and Altman difference plot. One hundred and forty-seven paired measurements were analysed. The average bias between the two methods (EPT vs. APS) was -1.6 mmHg (95 % confidence interval [CI]: -3.0 to -0.2 mmHg). The coefficient of correlation was 1.0084. The aneroid system showed an almost perfect agreement with the EPT. This study shows that it can be used in a clinical setting as well as under field conditions to measure arterial blood pressure in cattle.

A comparison of two ambulatory blood pressure monitors worn at the same time.

PubMed

Kallem, Radhakrishna R; Meyers, Kevin E C; Sawinski, Deirdre L; Townsend, Raymond R

2013-05-01

There are limited data in the literature comparing two simultaneously worn ambulatory blood pressure (BP) monitoring (ABPM) devices. The authors compared BPs from two monitors (Mobil-O-Graph [I.E.M., Stolberg, Germany] and Spacelabs 90207 [Spacelabs Medical, Issequah, WA]). In the nonrandomized component of the study, simultaneous 8-hour BP and heart rate data were measured by Mobil-O-Graph, consistently applied to the nondominant arm, and Spacelabs to the dominant arm on 12 untreated adults. Simultaneous 8-hour BP and heart data were obtained by the same monitors randomly assigned to a dominant or nondominant arm on 12 other untreated adults. Oscillometric BP profiles were obtained in the dominant and nondominant arms of the above 24 patients using an Accutorr (Datascope, Mahwah, NJ) device. The Spacelabs monitor recorded a 10.2-mm Hg higher systolic pressure in the nonrandomized (P=.0016) and a 7.9-mm Hg higher systolic pressure in the randomized studies (P=.00008) compared with the Mobil-O-Graph. The mean arterial pressures were 1 mm Hg to 2 mm Hg different between monitors in the two studies, and heart rates were nearly identical. Our observations, if confirmed in larger cohorts, support the concern that ABPM device manufacturers consider developing normative databases for their devices. ©2013 Wiley Periodicals, Inc.

Noninvasive Intracranial Volume and Pressure Measurements Using Ultrasound (Head and Spinal)

NASA Technical Reports Server (NTRS)

Hargens, Alan R.

1999-01-01

Prevention of secondary brain injuries following head trauma can be accomplished most easily when intracranial pressure (ICP) is monitored. However, current measurement techniques are invasive and thus not practical in the combat environment. The Pulsed Phase Lock Loop device, which was developed and patented by consultants Drs. Yost and Cantrell, uses a unique, noninvasive ultrasonic phase comparison method to measure slight changes in cranial volume which occur with changes in ICP. Year two studies included whole body head-up and head-down tilting effects on intracranial compliance and pressure in six healthy volunteers.

Effect of gas filling pressure and operation energy on ion and neutron emission in a medium energy plasma focus device

NASA Astrophysics Data System (ADS)

Niranjan, Ram; Rout, R. K.; Srivastava, Rohit; Kaushik, T. C.

2018-03-01

The effects of gas filling pressure and operation energy on deuterium ions and neutrons have been studied in a medium energy plasma focus device, MEPF-12. The deuterium gas filling pressure was varied from 1 to 10 mbar at an operation energy of 9.7 kJ. Also, the operation energy was varied from 3.9 to 9.7 kJ at a deuterium gas filling pressure of 4 mbar. Time resolved emission of deuterium ions was measured using a Faraday cup. Simultaneously, time integrated and time resolved emissions of neutrons were measured using a silver activation detector and plastic scintillator detector, respectively. Various characteristics (fluence, peak density, and most probable energy) of deuterium ions were estimated using the Faraday cup signal. The fluence was found to be nearly independent of the gas filling pressure and operation energy, but the peak density and most probable energy of deuterium ions were found to be varying. The neutron yield was observed to be varying with the gas filling pressure and operation energy. The effect of ions on neutrons emission was observed at each operation condition.

Noise levels of neonatal high-flow nasal cannula devices--an in-vitro study.

PubMed

König, Kai; Stock, Ellen L; Jarvis, Melanie

2013-01-01

Excessive ambient noise levels have been identified as a potential risk factor for adverse outcome in very preterm infants. Noise level measurements for continuous positive airway pressure (CPAP) devices demonstrated that these constantly exceed current recommendations. The use of high-flow nasal cannula (HFNC) as an alternative non-invasive ventilation modality has become more popular in recent years in neonatal care. To study noise levels of two HFNC devices commonly used in newborns. As a comparison, noise levels of a continuous flow CPAP device were also studied. In-vitro study. The noise levels of two contemporary HFNC devices (Fisher & Paykel NHF™ and Vapotherm Precision Flow®) and one CPAP device (Dräger Babylog® 8000 plus) were measured in the oral cavity of a newborn manikin in an incubator in a quiet environment. HFNC flows of 4-8 l/min and CPAP pressures of 4-8 cm H2O were applied. The CPAP flow was set at 8 l/min as per unit practice. Vapotherm HFNC generated the highest noise levels, measuring 81.2-91.4 dB(A) with increasing flow. Fisher & Paykel HFNC noise levels were between 78.8 and 81.2 dB(A). The CPAP device generated the lowest noise levels between 73.9 and 77.4 dB(A). Both HFNC devices generated higher noise levels than the CPAP device. All noise levels were far above current recommendations of the American Academy of Pediatrics. In light of the long duration of non-invasive respiratory support of very preterm infants, less noisy devices are required to prevent the potentially adverse effects of continuing excessive noise exposure in the neonatal intensive care unit. Copyright © 2013 S. Karger AG, Basel.

Device and method for measuring multi-phase fluid flow in a conduit using an elbow flow meter

DOEpatents

Ortiz, M.G.; Boucher, T.J.

1997-06-24

A system is described for measuring fluid flow in a conduit. The system utilizes pressure transducers disposed generally in line upstream and downstream of the flow of fluid in a bend in the conduit. Data from the pressure transducers is transmitted to a microprocessor or computer. The pressure differential measured by the pressure transducers is then used to calculate the fluid flow rate in the conduit. Control signals may then be generated by the microprocessor or computer to control flow, total fluid dispersed, (in, for example, an irrigation system), area of dispersal or other desired effect based on the fluid flow in the conduit. 2 figs.

Lab-on-a-chip based total-phosphorus analysis device utilizing a photocatalytic reaction

NASA Astrophysics Data System (ADS)

Jung, Dong Geon; Jung, Daewoong; Kong, Seong Ho

2018-02-01

A lab-on-a-chip (LOC) device for total phosphorus (TP) analysis was fabricated for water quality monitoring. Many commercially available TP analysis systems used to estimate water quality have good sensitivity and accuracy. However, these systems also have many disadvantages such as bulky size, complex pretreatment processes, and high cost, which limit their application. In particular, conventional TP analysis systems require an indispensable pretreatment step, in which the fluidic analyte is heated to 120 °C for 30 min to release the dissolved phosphate, because many phosphates are soluble in water at a standard temperature and pressure. In addition, this pretreatment process requires elevated pressures of up to 1.1 kg cm-2 in order to prevent the evaporation of the heated analyte. Because of these limiting conditions required by the pretreatment processes used in conventional systems, it is difficult to miniaturize TP analysis systems. In this study, we employed a photocatalytic reaction in the pretreatment process. The reaction was carried out by illuminating a photocatalytic titanium dioxide (TiO2) surface formed in a microfluidic channel with ultraviolet (UV) light. This pretreatment process does not require elevated temperatures and pressures. By applying this simplified, photocatalytic-reaction-based pretreatment process to a TP analysis system, greater degrees of freedom are conferred to the design and fabrication of LOC devices for TP monitoring. The fabricated LOC device presented in this paper was characterized by measuring the TP concentration of an unknown sample, and comparing the results with those measured by a conventional TP analysis system. The TP concentrations of the unknown sample measured by the proposed LOC device and the conventional TP analysis system were 0.018 mgP/25 mL and 0.019 mgP/25 mL, respectively. The experimental results revealed that the proposed LOC device had a performance comparable to the conventional bulky TP analysis system. Therefore, our device could be directly employed in water quality monitoring as an alternative to conventional TP analysis systems.

From Pressure to Path: Barometer-based Vehicle Tracking

PubMed Central

Ho, Bo-Jhang; Martin, Paul; Swaminathan, Prashanth; Srivastava, Mani

2017-01-01

Pervasive mobile devices have enabled countless context-and location-based applications that facilitate navigation, life-logging, and more. As we build the next generation of smart cities, it is important to leverage the rich sensing modalities that these numerous devices have to offer. This work demonstrates how mobile devices can be used to accurately track driving patterns based solely on pressure data collected from the device’s barometer. Specifically, by correlating pressure time-series data against topographic elevation data and road maps for a given region, a centralized computer can estimate the likely paths through which individual users have driven, providing an exceptionally low-power method for measuring driving patterns of a given individual or for analyzing group behavior across multiple users. This work also brings to bear a more nefarious side effect of pressure-based path estimation: a mobile application can, without consent and without notifying the user, use pressure data to accurately detect an individual’s driving behavior, compromising both user privacy and security. We further analyze the ability to predict driving trajectories in terms of the variance in barometer pressure and geographical elevation, demonstrating cases in which more than 80% of paths can be accurately predicted. PMID:29503981

The Camino intracranial pressure device in clinical practice. Assessment in a 1000 cases.

PubMed

Gelabert-González, M; Ginesta-Galan, V; Sernamito-García, R; Allut, A G; Bandin-Diéguez, J; Rumbo, R M

2006-04-01

Intracranial pressure (ICP) monitoring has become standard in the management of neurocritical patients. A variety of monitoring techniques and devices are available, each offering advantages and disadvantages. Analysis of large populations has never been performed. A prospective study was designed to evaluate the Camino fiberoptic intraparenchymal cerebral pressure monitor for complications and accuracy. Between 1992-2004 one thousand consecutive patients had a fiberoptic ICP monitor placed. The most frequent indication for monitoring was severe head injury (697 cases). The average duration of ICP monitoring was 184.6 +/- 94.3 hours; the range was 16-581 hours. Zero drift (range, -17 to 21 mm Hg; mean 7.3 +/- 5.1) was recorded after the devices were removed from 624 patients. Mechanical complications such as: breakage of the optical fiber (n = 17); dislocations of the fixation screw (n = 15) or the probe (n = 13); and failure of ICP recording for unknown reasons (n = 4) were found in 49 Camino devices. The Camino ICP sensor remains one of the most popular ICP monitoring devices for use in critical neurosurgical patients. The system offers reliable ICP measurements in an acceptable percentage of device complications and the advantage of in vivo recalibration. The incidence of technical complications was low and similar to others devices.

Blood pressure measurement and display system

NASA Technical Reports Server (NTRS)

Farkas, A. J.

1972-01-01

System is described that employs solid state circuitry to transmit visual display of patient's blood pressure. Response of sphygmomanometer cuff and microphone provide input signals. Signals and their amplitudes, from turn-on time to turn-off time, are continuously fed to data transmitter which transmits to display device.

40 CFR 60.384 - Monitoring of operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... wet scrubbing emission control device. The monitoring device must be certified by the manufacturer to be accurate within ±250 pascals (±1 inch water) gauge pressure and must be calibrated on an annual... continuous measurement of the scrubbing liquid flow rate to a wet scrubber for any affected facility using...

40 CFR 60.384 - Monitoring of operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... wet scrubbing emission control device. The monitoring device must be certified by the manufacturer to be accurate within ±250 pascals (±1 inch water) gauge pressure and must be calibrated on an annual... continuous measurement of the scrubbing liquid flow rate to a wet scrubber for any affected facility using...

40 CFR 60.384 - Monitoring of operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... wet scrubbing emission control device. The monitoring device must be certified by the manufacturer to be accurate within ±250 pascals (±1 inch water) gauge pressure and must be calibrated on an annual... continuous measurement of the scrubbing liquid flow rate to a wet scrubber for any affected facility using...

40 CFR 60.384 - Monitoring of operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... wet scrubbing emission control device. The monitoring device must be certified by the manufacturer to be accurate within ±250 pascals (±1 inch water) gauge pressure and must be calibrated on an annual... continuous measurement of the scrubbing liquid flow rate to a wet scrubber for any affected facility using...

40 CFR 60.384 - Monitoring of operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... wet scrubbing emission control device. The monitoring device must be certified by the manufacturer to be accurate within ±250 pascals (±1 inch water) gauge pressure and must be calibrated on an annual... continuous measurement of the scrubbing liquid flow rate to a wet scrubber for any affected facility using...

A universal standard for the validation of blood pressure measuring devices: Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Collaboration Statement.

PubMed

Stergiou, George S; Alpert, Bruce; Mieke, Stephan; Asmar, Roland; Atkins, Neil; Eckert, Siegfried; Frick, Gerhard; Friedman, Bruce; Graßl, Thomas; Ichikawa, Tsutomu; Ioannidis, John P; Lacy, Peter; McManus, Richard; Murray, Alan; Myers, Martin; Palatini, Paolo; Parati, Gianfranco; Quinn, David; Sarkis, Josh; Shennan, Andrew; Usuda, Takashi; Wang, Jiguang; Wu, Colin O; O'Brien, Eoin

2018-03-01

: In the last 30 years, several organizations, such as the US Association for the Advancement of Medical Instrumentation (AAMI), the British Hypertension Society, the European Society of Hypertension (ESH) Working Group on Blood Pressure (BP) Monitoring and the International Organization for Standardization (ISO) have developed protocols for clinical validation of BP measuring devices. However, it is recognized that science, as well as patients, consumers and manufacturers would be best served if all BP measuring devices were assessed for accuracy according to an agreed single validation protocol that had global acceptance. Therefore, an international initiative was taken by AAMI, ESH and ISO experts who agreed to develop a universal standard for device validation. This statement presents the key aspects of a validation procedure, which were agreed by the AAMI, ESH and ISO representatives as the basis for a single universal validation protocol. As soon as the AAMI/ESH/ISO standard is fully developed, this will be regarded as the single universal standard and will replace all other previous standards/protocols.

A Universal Standard for the Validation of Blood Pressure Measuring Devices: Association for the Advancement of Medical Instrumentation/European Society of Hypertension/International Organization for Standardization (AAMI/ESH/ISO) Collaboration Statement.

PubMed

Stergiou, George S; Alpert, Bruce; Mieke, Stephan; Asmar, Roland; Atkins, Neil; Eckert, Siegfried; Frick, Gerhard; Friedman, Bruce; Graßl, Thomas; Ichikawa, Tsutomu; Ioannidis, John P; Lacy, Peter; McManus, Richard; Murray, Alan; Myers, Martin; Palatini, Paolo; Parati, Gianfranco; Quinn, David; Sarkis, Josh; Shennan, Andrew; Usuda, Takashi; Wang, Jiguang; Wu, Colin O; O'Brien, Eoin

2018-03-01

In the past 30 years, several organizations, such as the US Association for the Advancement of Medical Instrumentation (AAMI), the British Hypertension Society, the European Society of Hypertension (ESH) Working Group on Blood Pressure (BP) Monitoring, and the International Organization for Standardization (ISO), have developed protocols for clinical validation of BP measuring devices. However, it is recognized that science, as well as patients, consumers, and manufacturers, would be best served if all BP measuring devices were assessed for accuracy according to an agreed single validation protocol that had global acceptance. Therefore, an international initiative was taken by the AAMI, ESH, and ISO experts who agreed to develop a universal standard for device validation. This statement presents the key aspects of a validation procedure, which were agreed by the AAMI, ESH, and ISO representatives as the basis for a single universal validation protocol. As soon as the AAMI/ESH/ISO standard is fully developed, this will be regarded as the single universal standard and will replace all other previous standards/protocols. © 2018 American Heart Association, Inc., and Wolters Kluwer Health, Inc.

21 CFR 870.1100 - Blood pressure alarm.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Blood pressure alarm. 870.1100 Section 870.1100...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1100 Blood pressure alarm. (a) Identification. A blood pressure alarm is a device that accepts the signal from a blood pressure...

21 CFR 870.1100 - Blood pressure alarm.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Blood pressure alarm. 870.1100 Section 870.1100...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1100 Blood pressure alarm. (a) Identification. A blood pressure alarm is a device that accepts the signal from a blood pressure...

21 CFR 870.1100 - Blood pressure alarm.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Blood pressure alarm. 870.1100 Section 870.1100...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1100 Blood pressure alarm. (a) Identification. A blood pressure alarm is a device that accepts the signal from a blood pressure...

21 CFR 870.1100 - Blood pressure alarm.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Blood pressure alarm. 870.1100 Section 870.1100...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1100 Blood pressure alarm. (a) Identification. A blood pressure alarm is a device that accepts the signal from a blood pressure...

Esophagogastric Junction pressure morphology: comparison between a station pull-through and real-time 3D-HRM representation.

PubMed

Nicodème, F; Lin, Z; Pandolfino, J E; Kahrilas, P J

2013-09-01

Esophagogastric junction (EGJ) competence is the fundamental defense against reflux making it of great clinical significance. However, characterizing EGJ competence with conventional manometric methodologies has been confounded by its anatomic and physiological complexity. Recent technological advances in miniaturization and electronics have led to the development of a novel device that may overcome these challenges. Nine volunteer subjects were studied with a novel 3D-HRM device providing 7.5 mm axial and 45° radial pressure resolution within the EGJ. Real-time measurements were made at rest and compared to simulations of a conventional pull-through made with the same device. Moreover, 3D-HRM recordings were analyzed to differentiate contributing pressure signals within the EGJ attributable to lower esophageal sphincter (LES), diaphragm, and vasculature. 3D-HRM recordings suggested that sphincter length assessed by a pull-through method greatly exaggerated the estimate of LES length by failing to discriminate among circumferential contractile pressure and asymmetric extrinsic pressure signals attributable to diaphragmatic and vascular structures. Real-time 3D EGJ recordings found that the dominant constituents of EGJ pressure at rest were attributable to the diaphragm. 3D-HRM permits real-time recording of EGJ pressure morphology facilitating analysis of the EGJ constituents responsible for its function as a reflux barrier making it a promising tool in the study of GERD pathophysiology. The enhanced axial and radial recording resolution of the device should facilitate further studies to explore perturbations in the physiological constituents of EGJ pressure in health and disease. © 2013 John Wiley & Sons Ltd.

Measurement of in-plane elasticity of live cell layers using a pressure sensor embedded microfluidic device

NASA Astrophysics Data System (ADS)

Lin, Chien-Han; Wang, Chien-Kai; Chen, Yu-An; Peng, Chien-Chung; Liao, Wei-Hao; Tung, Yi-Chung

2016-11-01

In various physiological activities, cells experience stresses along their in-plane direction when facing substrate deformation. Capability of continuous monitoring elasticity of live cell layers during a period is highly desired to investigate cell property variation during various transformations under normal or disease states. This paper reports time-lapsed measurement of live cell layer in-plane elasticity using a pressure sensor embedded microfluidic device. The sensor converts pressure-induced deformation of a flexible membrane to electrical signals. When cells are cultured on top of the membrane, flexural rigidity of the composite membrane increases and further changes the output electrical signals. In the experiments, human embryonic lung fibroblast (MRC-5) cells are cultured and analyzed to estimate the in-plane elasticity. In addition, the cells are treated with a growth factor to simulate lung fibrosis to study the effects of cell transformation on the elasticity variation. For comparison, elasticity measurement on the cells by atomic force microscopy (AFM) is also performed. The experimental results confirm highly anisotropic configuration and material properties of cells. Furthermore, the in-plane elasticity can be monitored during the cell transformation after the growth factor stimulation. Consequently, the developed microfluidic device provides a powerful tool to study physical properties of cells for fundamental biophysics and biomedical researches.

In-line pressure within a HOTLINE® Fluid Warmer, under various flow conditions.

PubMed

Higashi, Midoriko; Yamaura, Ken; Matsubara, Yukie; Fukudome, Takuya; Hoka, Sumio

2015-04-01

Roller pump infusion devices are widely used for rapid infusion, and may be combined with separate warming devices. There may be instances however, where the pressures generated by the roller pump may not be compatible with the warming device. We assessed a commonly used roller pump in combination with a HOTLINE® Fluid Warmer, and found that it could generate pressures exceeding the HOTLINE® manufacturers specifications. This was of concern because the HOTLINE® manufacturer guideline states that not for use with pressure devices generating over 300 mmHg. Pressure greater than 300 mmHg may compromise the integrity of the HOTLINE® Fluid Warming Set. The aim of this study was to compare in-line pressure within a HOTLINE® Fluid Warmer at different infusion rates of a roller pump using various sizes of intravenous cannulae. The rapid infusion system comprised a 500 mL-normal saline bag, roller pump type infusion device, HOTLINE® Fluid Warmer (blood and fluid warmer system), and six different sizes of intravenous cannulae. In-line pressure was measured proximal to the HOTLINE® (pre-warmer) and proximal to the cannula (post-warmer), at flow rate of 50-160 mL/min. The in-line pressures increased significantly with increasing flow rate. The pre-warmer pressures exceeded 300 mmHg when the flow rate was ≥120 mL/min with 20-gauge, 48 mm length cannula, 130 with 20-gauge, 25 mm cannula, and 160 mL/min with 18-gauge, 48 mm cannula. However, they were <300 mmHg at any flow rates with 18-gauge, 30 mm cannula and 16-gauge cannulae. The post-warmer pressures exceeded 300 mmHg at the flow rate of 140 mL/min with 20-gauge, 48 mm cannula, and 160 mL/min with 20-gauge, 25 mm cannula, while they were <300 mmHg at any flow rates with 18 and 16-gauge cannulae. The in-line pressure within a HOTLINE® could exceed 300 mmHg, depending on the flow rate and size and length of cannula. It is important to pay attention to the size and length of cannulae and flow rate to keep the maximum in-line pressure<300 mmHg when a roller pump type infusion device is used.

A portable single-sided magnet system for remote NMR measurements of pulmonary function.

PubMed

Dabaghyan, Mikayel; Muradyan, Iga; Hrovat, Alan; Butler, James; Frederick, Eric; Zhou, Feng; Kyriazis, Angelos; Hardin, Charles; Patz, Samuel; Hrovat, Mirko

2014-12-01

In this work, we report initial results from a light-weight, low field magnetic resonance device designed to make relative pulmonary density measurements at the bedside. The development of this device necessarily involves special considerations for the magnet, RF and data acquisition schemes as well as a careful analysis of what is needed to provide useful information in the ICU. A homogeneous field region is created remotely from the surface of the magnet such that when the magnet is placed against the chest, an NMR signal is measured from a small volume in the lung. In order to achieve portability, one must trade off field strength and therefore spatial resolution. We report initial measurements from a ping-pong ball size region in the lung as a function of lung volume. As expected, we measured decreased signal at larger lung volumes since lung density decreases with increasing lung volume. Using a CPMG sequence with ΔTE=3.5 ms and a 20 echo train, a signal to noise ratio ~1100 was obtained from an 8.8mT planar magnet after signal averaging for 43 s. This is the first demonstration of NMR measurements made on a human lung with a light-weight planar NMR device. We argue that very low spatial resolution measurements of different lobar lung regions will provide useful diagnostic information for clinicians treating Acute Respiratory Distress Syndrome as clinicians want to avoid ventilator pressures that cause either lung over distension (too much pressure) or lung collapse (too little pressure). Copyright © 2014 John Wiley & Sons, Ltd.

A portable single-sided magnet system for remote NMR measurements of pulmonary function

PubMed Central

Mikayel, Dabaghyan; Iga, Muradyan; James, Butler; Eric, Frederick; Feng, Zhou; Angelos, Kyriazis; Charles, Hardin; Samuel, Patz; Mirko, Hrovat

2014-01-01

In this work, we report initial results from a light-weight, low field magnetic resonance device designed to make relative pulmonary density measurements at the bedside. The development of this device necessarily involves special considerations for the magnet, RF and data acquisition schemes as well as a careful analysis of what is needed to provide useful information in the ICU. A homogeneous field region is created remotely from the surface of the magnet such that when the magnet is placed against the chest, an NMR signal is measured from a small volume in the lung. In order to achieve portability, one must trade off field strength and therefore spatial resolution. We report initial measurements from a ping-pong ball size region in the lung as a function of lung volume. As expected, we measured decreased signal at larger lung volumes since lung density decreases with increasing lung volume. Using a CPMG sequence with ΔTE=3.5 ms and a 20 echo train, a signal to noise ratio ~1100 was obtained from an 8.8mT planar magnet after signal averaging for 43 s. This is the first demonstration of NMR measurements made on a human lung with a light-weight planar NMR device. We argue that very low spatial resolution measurements of different lobar lung regions will provide useful diagnostic information for clinicians treating Acute Respiratory Distress Syndrome as clinicians want to avoid ventilator pressures that cause either lung over distension (too much pressure) or lung collapse (too little pressure). PMID:24953556

Introduction of automated blood pressure devices intended for a low resource setting in rural Tanzania.

PubMed

Baker, Elinor Chloe; Hezelgrave, Natasha; Magesa, Stephen M; Edmonds, Sally; de Greeff, Annemarie; Shennan, Andrew

2012-04-01

Regular blood pressure (BP) monitoring is a cost-effective means of early identification and management of hypertensive disease in pregnancy. In much of rural sub-Saharan Africa, the ability to take and act on accurate BP measurements is lacking as a result of poorly functioning or absent equipment and/or inadequate staff education. This study describes the feasibility of using validated automated BP devices suitable for low-resource settings (LRS) in primary health-care facilities in rural Tanzania. Following a primary survey, 19 BP devices were distributed to 11 clinics and re-assessed at one, three, six, 12 and 36 months. Devices were used frequently with high levels of user satisfaction and good durability. We conclude that the use of automated BP devices in LRS is feasible and sustainable. An assessment of their ability to reduce maternal and perinatal morbidity and mortality is vital.

Graphene-based inline pressure sensor integrated with microfluidic elastic tube

NASA Astrophysics Data System (ADS)

Inoue, Nagisa; Onoe, Hiroaki

2018-01-01

We propose an inline pressure sensor composed of a polydimethylsiloxane (PDMS) microfluidic tube integrated with graphene sheets. The PDMS tube was fabricated through molding, and a multilayered graphene sheet was transferred on the surface of the PDMS tube. The pressure inside the tube was monitored using the changes in the electrical resistance of the transferred graphene. The proposed pressure sensor could be suitable for precise pressure measurement for a small amount of fluid in microfluidic systems including organ-on-a-chip devices.

Measurement of charge transport through organic semiconducting devices

NASA Astrophysics Data System (ADS)

Klenkler, Richard A.

2007-12-01

In this thesis, two important and unexplored areas of organic semiconductor device physics are investigated: The first area involves determining the effect of energy barriers and intermixing at the interfaces between hole transport layers (HTLs). This effect was discerned by first establishing a method of pressure-laminating successive solution coated HTLs to gether. It was found that in the range of 0.8--3.0 MPa a pressure-laminated interface between two identical HTLs causes no measurable perturbation to charge transport. By this method, 2 different HTLs can be sandwiched together to create a discrete interface, and by inserting a mixed HTL in the middle an intermixed interface between the 2 HTLs can be simulated. With these sandwiched devices, charge injection across discrete versus intermixed interfaces were compared using time-of-flight measurements. For the hole transport materials investigated, no perturbation to the overall charge transport was observed with the discrete interface, however in contrast the rate of charge transport was clearly reduced through the intermixed interface. The second area that was investigated pertains to the development of a bulk mobility measurement technique that has a higher resolution than existing methods. The approach that was used involved decoupling the charge carrier transient signal from the device charging circuit. With this approach, the RC time constant constraint that limits the resolution of existing methods is eliminated. The resulting method, termed the photoinduced electroluminescence (EL) mobility measurement technique, was then used to compare the electron mobility of the metal chelate, AlQ3 to that of the novel triazine material, BTB. Results showed that BTB demonstrated an order of magnitude higher mobility than AlQ3. Overall, these findings have broad implications regarding device design. The pressure-lamination method could be used, e.g., as a diagnostic tool to help in the design of multilayer xerographic photoreceptors, such as those that include an abrasion resistant overcoat. Further, the photoinduced EL technique could be use as a tool to help characterize charge flow and balance in organic light emitting devices amongst others.

Continuous and Cuffless Blood Pressure Monitoring Based on ECG and SpO2 Signals ByUsing Microsoft Visual C Sharp.

PubMed

Younessi Heravi, M A; Khalilzadeh, M A; Joharinia, S

2014-03-01

One of the main problems especially in operating room and monitoring devices is measurement of Blood Pressure (BP) by sphygmomanometer cuff. Objective :In this study we designed a new method to measure BP changes continuously for detecting information between cuff inflation times by using vital signals in monitoring devices. This will be achieved by extraction of the time difference between each cardiac cycle and a relative pulse wave. Finger pulse and ECG signals in lead I were recorded by a monitoring device. The output of monitoring device wasinserted in a computer by serial network communication. A software interface (Microsoft Visual C#.NET ) was used to display and process the signals in the computer. Time difference between each cardiac cycle and pulse signal was calculated throughout R wave detection in ECG and peak of pulse signal by the software. The relation between time difference in two waves and BP was determined then the coefficients of equation were obtained in different physical situations. The results of estimating BP were compared with the results of sphygmomanometer method and the error rate was calculated. In this study, 25 subjects participated among them 15 were male and 10 were female. The results showed that BP was linearly related to time difference. Average of coefficient correlation was 0.9±0.03 for systolic and 0.82±0.04 for diastolic blood pressure. The highest error percentage was calculated 8% for male and 11% for female group. Significant difference was observed between the different physical situation and arm movement changes. The relationship between time difference and age was estimated in a linear relationship with a correlation coefficient of 0.76. By determining linear relation values with high accuracy, BP can be measured with insignificant error. Therefore it can be suggested as a new method to measure the blood pressure continuously.

Acoustics of the piezo-electric pressure probe

NASA Technical Reports Server (NTRS)

Dutt, G. S.

1974-01-01

Acoustical properties of a piezoelectric device are reported for measuring the pressure in the plasma flow from an MPD arc. A description and analysis of the acoustical behavior in a piezoelectric probe is presented for impedance matching and damping. The experimental results are presented in a set of oscillographic records.

A Simple Boyle's Law Experiment.

ERIC Educational Resources Information Center

Lewis, Don L.

1997-01-01

Describes an experiment to demonstrate Boyle's law that provides pressure measurements in a familiar unit (psi) and makes no assumptions concerning atmospheric pressure. Items needed include bathroom scales and a 60-ml syringe, castor oil, disposable 3-ml syringe and needle, modeling clay, pliers, and a wooden block. Commercial devices use a…

21 CFR 862.1530 - Plasma oncometry test system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Plasma oncometry test system. 862.1530 Section 862....1530 Plasma oncometry test system. (a) Identification. A plasma oncometry test system is a device intended to measure plasma oncotic pressure. Plasma oncotic pressure is that portion of the total fluid...

21 CFR 862.1530 - Plasma oncometry test system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Plasma oncometry test system. 862.1530 Section 862....1530 Plasma oncometry test system. (a) Identification. A plasma oncometry test system is a device intended to measure plasma oncotic pressure. Plasma oncotic pressure is that portion of the total fluid...

21 CFR 862.1530 - Plasma oncometry test system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Plasma oncometry test system. 862.1530 Section 862....1530 Plasma oncometry test system. (a) Identification. A plasma oncometry test system is a device intended to measure plasma oncotic pressure. Plasma oncotic pressure is that portion of the total fluid...

21 CFR 862.1530 - Plasma oncometry test system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Plasma oncometry test system. 862.1530 Section 862....1530 Plasma oncometry test system. (a) Identification. A plasma oncometry test system is a device intended to measure plasma oncotic pressure. Plasma oncotic pressure is that portion of the total fluid...

21 CFR 862.1530 - Plasma oncometry test system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Plasma oncometry test system. 862.1530 Section 862....1530 Plasma oncometry test system. (a) Identification. A plasma oncometry test system is a device intended to measure plasma oncotic pressure. Plasma oncotic pressure is that portion of the total fluid...

Improved multiple-shot gun for use as a combustion stability rating device

NASA Technical Reports Server (NTRS)

Sokolowski, D. E.

1973-01-01

A program was conducted to develop and experimentally evaluate an improved version of a modified machine gun for use as a device for rating the relative combustion stability of various rocket combustors. Following the results of a previous study involving a caliber .30 machine gun, a caliber .50 machine gun was modified in order to extend the charge-size range of the device. Nitrocellulose charge sizes ranging from 1.004 to 9.720 grams were fired at rates up to four shots per second. Shock pressures up to 25,512 kN/sq m were measured near the end of a shortened gun barrel. A minimal resistance type of check valve permitted the gun to fire into pressurized regions; back pressures up to 3448 kN/sq m abs were tested. The final modified assembly was evaluated during combustion stability tests on rocket combustors burning a FLOX-methane propellant combination.

Validation of the Omron M3 Intellisense (HEM-7051-E) upper arm blood pressure monitor, for self-measurement, according to the European Society of Hypertension International Protocol revision 2010 in a stage 3-5 chronic kidney disease population.

PubMed

Akpolat, Tekin; Erdem, Emre; Aydogdu, Türkan

2012-01-01

Encouragement of home blood pressure (BP) monitoring has a great potential to improve hypertension control rates. The purpose of this study was to test validation of the Omron M3 Intellisense (HEM-7051-E) upper arm BP measuring monitor for self-measurement according to the European Society of Hypertension International Protocol revision 2010 (ESH-IP2) in stage 3-5 chronic kidney disease (CKD) patients. 66 patients having CKD stage 3-5 were included in the study. Nine consecutive measurements were made according to the ESH-IP2 protocol. The Omron M3 Intellisense device fulfills the validation criteria of the ESH-IP2 for stage 3-5 CKD patients. Although arterial stiffness can affect accurate BP measurement, there are limited data regarding the use of automated oscillometric devices in CKD. To our knowledge, this is the first study investigating validation of an oscillometric device in stage 3-5 predialysis CKD patients. This study validates the Omron M3 Intellisense upper arm device for stage 3-5 CKD patients. New validation studies investigating other oscillometric sphygmomanometers for CKD patients and involvement of nephrologists in these studies have great potential to increase patient care in CKD. Copyright © 2011 S. Karger AG, Basel.

Fibre optic sensors for temperature and pressure monitoring in laser ablation: experiments on ex-vivo animal model

NASA Astrophysics Data System (ADS)

Tosi, Daniele; Saccomandi, Paola; Schena, Emiliano; Duraibabu, Dinesh B.; Poeggel, Sven; Adilzhan, Abzal; Aliakhmet, Kamilla; Silvestri, Sergio; Leen, Gabriel; Lewis, Elfed

2016-05-01

Optical fibre sensors have been applied to perform biophysical measurement in ex-vivo laser ablation (LA), on pancreas animal phantom. Experiments have been performed using Fibre Bragg Grating (FBG) arrays for spatially resolved temperature detection, and an all-glass Extrinsic Fabry-Perot Interferometer (EFPI) for pressure measurement. Results using a Nd:YAG laser source as ablation device, are presented and discussed.

Phase Interrogation Used for a Wireless Passive Pressure Sensor in an 800 °C High-Temperature Environment

PubMed Central

Zhang, Huixin; Hong, Yingping; Liang, Ting; Zhang, Hairui; Tan, Qiulin; Xue, Chenyang; Liu, Jun; Zhang, Wendong; Xiong, Jijun

2015-01-01

A wireless passive pressure measurement system for an 800 °C high-temperature environment is proposed and the impedance variation caused by the mutual coupling between a read antenna and a LC resonant sensor is analyzed. The system consists of a ceramic-based LC resonant sensor, a readout device for impedance phase interrogation, heat insulating material, and a composite temperature-pressure test platform. Performances of the pressure sensor are measured by the measurement system sufficiently, including pressure sensitivity at room temperature, zero drift from room temperature to 800 °C, and the pressure sensitivity under the 800 °C high temperature environment. The results show that the linearity of sensor is 0.93%, the repeatability is 6.6%, the hysteretic error is 1.67%, and the sensor sensitivity is 374 KHz/bar. The proposed measurement system, with high engineering value, demonstrates good pressure sensing performance in a high temperature environment. PMID:25690546

Profiling wrist pulse from skin surface by Advanced Vibrometer Interferometer Device

NASA Astrophysics Data System (ADS)

Lee, Hao-Xiang; Lee, Shu-Sheng; Hsu, Yu-Hsiang; Lee, Chih-Kung

2017-02-01

With global trends in population aging, the need to decrease and prevent the onset of cardiovascular disease has drawn a great attention. The traditional cuff-based upper arm sphygmomanometer is still the standard method to retrieve blood pressure information for diagnostics. However, this method is not easy to be adapted by patients and is not comfortable enough to perform a long term monitoring process. In order to correlate the beating profile of the arterial pulse on the wrist skin, an Advanced Vibrometer Interferometer Device (AVID) is adopted in this study to measure the vibration amplitude of skin and compare it with blood pressure measured from the upper arm. The AVID system can measure vibration and remove the directional ambiguity by using circular polarization interferometer technique with two orthogonal polarized light beams. The displacement resolution of the system is nearly 1.0 nm and the accuracy is experimentally verified. Using an optical method to quantify wrist pule, it provides a means to perform cuff-less, noninvasive and continuous measurement. In this paper, the correlations between the amplitude of skin vibration and the actual blood pressure is studied. The success of this method could potentially set the foundation of blood pressure monitor system based on optical approaches.

Pressure in isochoric systems containing aqueous solutions at subzero Centigrade temperatures.

PubMed

Ukpai, Gideon; Năstase, Gabriel; Șerban, Alexandru; Rubinsky, Boris

2017-01-01

Preservation of biological materials at subzero Centigrade temperatures, cryopreservation, is important for the field of tissue engineering and organ transplantation. Our group is studying the use of isochoric (constant volume) systems of aqueous solution for cryopreservation. Previous studies measured the pressure-temperature relations in aqueous isochoric systems in the temperature range from 0°C to - 20°C. The goal of this study is to expand the pressure-temperature measurement beyond the range reported in previous publications. To expand the pressure-temperature measurements beyond the previous range, we have developed a new isochoric device capable of withstanding liquid nitrogen temperatures and pressures of up to 413 MPa. The device is instrumented with a pressure transducer than can monitor and record the pressures in the isochoric chamber in real time. Measurements were made in a temperature range from - 5°C to liquid nitrogen temperatures for various solutions of pure water and Me2SO (a chemical additive used for protection of biological materials in a frozen state and for vitrification (glass formation) of biological matter). Undissolved gaseous are is carefully removed from the system. Temperature-pressure data from - 5°C to liquid nitrogen temperature for pure water and other solutions are presented in this study. Following are examples of some, temperature-pressure values, that were measured in an isochoric system containing pure water: (- 20°C, 187 MPa); (-25°C, 216 MPa); (- 30°C, 242.3 MPa); (-180°C, 124 MPa). The data is consistent with the literature, which reports that the pressure and temperature at the triple point, between ice I, ice III and water is, - 21.993°C and 209.9 MPa, respectively. It was surprising to find that the pressure in the isochoric system increases at temperatures below the triple point and remains high to liquid nitrogen temperatures. Measurements of pressure-temperature relations in solutions of pure water and Me2SO in different concentrations show that, for concentrations in which vitrification is predicted, no increase in pressure was measured during rapid cooling to liquid nitrogen temperatures. However, ice formation either during cooling or warming to and from liquid nitrogen temperatures produced an increase in pressure. The data obtained in this study can be used to aid in the design of isochoric cryopreservation protocols. The results suggest that the pressure measurement is important in the design of "constant volume" systems and can provide a simple means to gain information on the occurrence of vitrification and devitrification during cryopreservation processes of aqueous solutions in an isochoric system.

Laboratory experiments duplicate conditions in the Earth’s crust

USGS Publications Warehouse

Peselnick, L.; Dieterich, J.H.; Stewart, R.M.

1974-01-01

An experimental device that simulates conditions in the Earth's crust at depths of up to 30 kilometers has been constructed by geophysicists working at the U.S Geological Survey laboratories in Menlo Park, California. A high pressure "bomb" is being used to experimentally measure the velocity of seismic waves in different types of rock at various confining pressures and temperatures. The principal purpose of these measurements is to determine the elastic and non-elastic properties of rocks and minerals under conditions of high-pressure such as exist deep in the Earth's crust. 

Characterization of fiber Bragg grating-based sensor array for high resolution manometry

NASA Astrophysics Data System (ADS)

Becker, Martin; Rothhardt, Manfred; Schröder, Kerstin; Voigt, Sebastian; Mehner, Jan; Teubner, Andreas; Lüpke, Thomas; Thieroff, Christoph; Krüger, Matthias; Chojetzki, Christoph; Bartelt, Hartmut

2012-04-01

The combination of fiber Bragg grating arrays integrated in a soft plastic tube is promising for high resolution manometry (HRM) where pressure measurements are done with high spatial resolution. The application as a medical device and in vivo experiments have to be anticipated by characterization with a measurement setup that simulates natural conditions. Good results are achieved with a pressure chamber which applies a well-defined pressure with a soft tubular membrane. It is shown that the proposed catheter design reaches accuracies down to 1 mbar and 1 cm.

Temperature-independent fiber-Bragg-grating-based atmospheric pressure sensor

NASA Astrophysics Data System (ADS)

Zhang, Zhiguo; Shen, Chunyan; Li, Luming

2018-03-01

Atmospheric pressure is an important way to achieve a high degree of measurement for modern aircrafts, moreover, it is also an indispensable parameter in the meteorological telemetry system. With the development of society, people are increasingly concerned about the weather. Accurate and convenient atmospheric pressure parameters can provide strong support for meteorological analysis. However, electronic atmospheric pressure sensors currently in application suffer from several shortcomings. After an analysis and discussion, we propose an innovative structural design, in which a vacuum membrane box and a temperature-independent strain sensor based on an equal strength cantilever beam structure and fiber Bragg grating (FBG) sensors are used. We provide experimental verification of that the atmospheric pressure sensor device has the characteristics of a simple structure, lack of an external power supply, automatic temperature compensation, and high sensitivity. The sensor system has good sensitivity, which can be up to 100 nm/MPa, and repeatability. In addition, the device exhibits desired hysteresis.

Comparative study of methodologies for pulse wave velocity estimation.

PubMed

Salvi, P; Magnani, E; Valbusa, F; Agnoletti, D; Alecu, C; Joly, L; Benetos, A

2008-10-01

Arterial stiffness, estimated by pulse wave velocity (PWV), is an independent predictor of cardiovascular mortality and morbidity. However, the clinical applicability of these measurements and the elaboration of reference PWV values are difficult due to differences between the various devices used. In a population of 50 subjects aged 20-84 years, we compared PWV measurements with three frequently used devices: the Complior and the PulsePen, both of which determine aortic PWV as the delay between carotid and femoral pressure wave and the PulseTrace, which estimates the Stiffness Index (SI) by analyzing photoplethysmographic waves acquired on the fingertip. PWV was measured twice by each device. Coefficient of variation of PWV was 12.3, 12.4 and 14.5% for PulsePen, Complior and PulseTrace, respectively. These measurements were compared with the reference method, that is, a simultaneous acquisition of pressure waves using two tonometers. High correlation coefficients with the reference method were observed for PulsePen (r = 0.99) and Complior (r = 0.83), whereas for PulseTrace correlation with the reference method was much lower (r = 0.55). Upon Bland-Altman analysis, mean differences of values +/- 2s.d. versus the reference method were -0.15 +/- 0.62 m/s, 2.09 +/- 2.68 m/s and -1.12 +/- 4.92 m/s, for PulsePen, Complior and Pulse-Trace, respectively. This study confirms the reliability of Complior and PulsePen devices in estimating PWV, while the SI determined by the PulseTrace device was found to be inappropriate as a surrogate of PWV. The present results indicate the urgent need for evaluation and comparison of the different devices to standardize PWV measurements and establish reference values.

Validation of the A&D BP UB-542 wrist device for home blood pressure measurement according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Saladini, Francesca; Benetti, Elisabetta; Fania, Claudio; Palatini, Paolo

2013-08-01

The objective of this study was to determine the accuracy of the A&D BP UB-542 wrist device for home blood pressure (BP) measurement according to the International Protocol of the European Society of Hypertension (ESH). Device evaluation was carried out in 33 patients. The mean age was 50.9±10.1 years, the mean systolic BP was 141.6±22.8 mmHg (range 92 : 189), the mean diastolic BP was 89.2±11.4 mmHg (range 62 : 120), the mean arm circumference was 28.8±3.2 cm (range 23-35), and the mean wrist circumference was 17.1±1.4 cm (range 14-19.5). The protocol requirements were followed precisely. The device passed all requirements, fulfilling the standards of the protocol. On average, the device overestimated the systolic BP by 1.8±7.2 mmHg and diastolic BP by 1.6±5.7 mmHg. These data show that the A&D BP UB-542 wrist device met the requirements for validation by the International Protocol and can be recommended for clinical use in the adult population.

Measuring Soil Moisture using the Signal Strength of Buried Bluetooth Devices.

NASA Astrophysics Data System (ADS)

Hut, R.; Campbell, C. S.

2015-12-01

A low power bluetooth Low Energy (BLE) device is burried 20cm into the soil and a smartphone is placed on top of the soil to test if bluetooth signal strength can be related to soil moisture. The smartphone continuesly records and stores bluetooth signal strength of the device. The soil is artifcially wetted and drained. Results show a relation between BLE signal strength and soil moisture that could be used to measure soil moisture using these off-the-shelf consumer electronics. This opens the possibily to develop sensors that can be buried into the soil, possibly below the plow-line. These sensors can measure local parameters such as electric conductivity, ph, pressure, etc. Readings would be uploaded to a device on the surface using BLE. The signal strength of this BLE would be an (additional) measurement of soil moisture.

THERMAL CONDUCTIVITY ANALYSIS OF GASES

DOEpatents

Clark, W.J.

1949-06-01

This patent describes apparatus for the quantitative analysis of a gaseous mixture at subatmospheric pressure by measurement of its thermal conductivity. A heated wire forms one leg of a bridge circuit, while the gas under test is passed about the wire at a constant rate. The bridge unbalance will be a measure of the change in composition of the gas, if compensation is made for the effect due to gas pressure change. The apparatus provides a voltage varying with fluctuations of pressure in series with the indicating device placed across the bridge, to counterbalance the voltage change caused by fluctuations in the pressure of the gaseous mixture.

The influence of local pressure on evaluation parameters of skin blood perfusion and fluorescence

NASA Astrophysics Data System (ADS)

Zherebtsov, E. A.; Kandurova, K. Y.; Seryogina, E. S.; Kozlov, I. O.; Dremin, V. V.; Zherebtsova, A. I.; Dunaev, A. V.; Meglinski, I.

2017-03-01

This article presents the results of the study of the pressure applied on optical diagnostic probes as a significant factor affecting the results of measurements. During stepwise increasing and decreasing of local pressure on skin we conducted measurements using the methods of laser Doppler flowmetry and fluorescence spectroscopy. It was found out that pressure on optical probe has sufficient impact on skin microcirculation to affect registered fluorescence intensity. Data obtained in this study are of interest for design and development of diagnostic technologies for wearable devices. This data will also inform further investigation into issues of compensation of blood absorption influence on fluorescence spectrum, allowing increased accuracy and reproducibility of measurements by fluorescence spectroscopy methods in optical diagnosis.

Continuous 24-hour measurement of middle ear pressure.

PubMed

Tideholm, B; Jönsson, S; Carlborg, B; Welinder, R; Grenner, J

1996-07-01

A new method was developed for continuous measurement of the middle ear pressure during a 24-h period. The equipment consisted of a piezo-electric pressure device and a digital memory. To allow continuous pressure recordings during normal every-day activities the equipment was made light and portable. The measurement accuracy of the equipment as well as the base-line and temperature stability were tested and found to meet to our requirements satisfactorily. In 4 volunteers with different middle ear conditions, a small perforation was made through the tympanic membrane. A rubber stopper containing a small polyethylene tube was fitted into the external ear canal. Tubal function tests were made to establish the equipment's ability to monitor fast pressure changes. The tests were well in accordance with other methods of direct pressure measurements. The equipment was carried by the volunteers for 24 h to monitor any slow or rapid dynamic pressure changes in the middle ear. Four continuous 24-h measurements are presented. The method was found to be suitable for valid measurements of dynamic pressure changes in the middle ear during normal every-day activities. It may become a useful instrument in the search for a better understanding of the development of chronic middle ear disease.

The time-dependent accumulation of protoporphyrin IX fluorescence in nodular basal cell carcinoma following application of methyl aminolevulinate with an oxygen pressure injection device.

PubMed

Blake, E; Campbell, S; Allen, J; Mathew, J; Helliwell, P; Curnow, A

2012-12-05

Topical protoporphyrin (PpIX)-induced photodynamic therapy (PDT) relies on the penetration of the prodrug into the skin lesion and subsequent accumulation of the photosensitizer. Methyl aminolevulinate (MAL)-PDT is an established treatment for thinner and superficial non-melanoma skin cancers (NMSCs) but for the treatment of the thicker nodular basal cell carcinoma (nBCC) enhanced penetration of the prodrug is required. This study employed a new higher pressure, oxygen pressure injection (OPI) device, at the time of Metvix® application with a view to enhancing the penetration of MAL into the tumors. Each patient had Metvix® applied to a single nBCC followed by application of a higher pressure OPI device. Following different time intervals (0, 30, 60, 120 or 180 min) the tumors were excised. The maximum depth and area of MAL penetration achieved in each lesion was measured using PpIX fluorescence microscopy. As expected, an increase in the depth of MAL-induced PpIX accumulation and area of tumor sensitized was observed over time; when the Metvix® cream was applied for 0, 30, 60, 120 and 180 min the median depth of PpIX fluorescence was 0%, 21%, 26.5%, 75.5% and 90%, respectively and the median area of tumor sensitized was 0%, 4%, 6%, 19% and 60%, respectively. As the investigation presented here did not include a control arm, the relative depths of fluorescence observed in this study were statistically compared (using the non-parametric Mann Whitney U test) with the results of our previous study where patients had Metvix® cream applied either with or without the standard pressure OPI device. When the higher pressure OPI device was employed compared to without OPI this increase was observed to be greater following 30, 120, and 180 min although overall not significantly (p=0.835). In addition, no significant difference between the higher pressure OPI device employed here and the previously investigated standard pressure OPI device was observed (p=0.403). However, when the results for both OPI devices were combined and compared to the standard treatment (no OPI employed) group, although the difference did not reach significance (p=0.531) a consistent and substantial increase in the depth of PpIX fluorescence was observed, therefore employment of an OPI device during topical MAL-PDT protocols warrants further investigation as a technique for enhancing MAL penetration. Copyright © 2012 Elsevier B.V. All rights reserved.

21 CFR 868.5860 - Pressure tubing and accessories.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pressure tubing and accessories. 868.5860 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5860 Pressure tubing and accessories. (a) Identification. Pressure tubing and accessories are flexible or rigid devices intended to...

A reliable measure of footwear upper comfort enabled by an innovative sock equipped with textile pressure sensors.

PubMed

Herbaut, Alexis; Simoneau-Buessinger, Emilie; Barbier, Franck; Cannard, Francis; Guéguen, Nils

2016-10-01

Footwear comfort is essential and pressure distribution on the foot was shown as a relevant objective measurement to assess it. However, asperities on the foot sides, especially the metatarsals and the instep, make its evaluation difficult with available equipment. Thus, a sock equipped with textile pressure sensors was designed. Results from the mechanical tests showed a high linearity of the sensor response under incremental loadings and allowed to determine the regression equation to convert voltage values into pressure measurements. The sensor response was also highly repeatable and the creep under constant loading was low. Pressure measurements on human feet associated with a perception questionnaire exhibited that significant relationships existed between pressure and comfort perceived on the first, the third and the fifth metatarsals and top of the instep. Practitioner Summary: A sock equipped with textile sensors was validated for measuring the pressure on the foot top, medial and lateral sides to evaluate footwear comfort. This device may be relevant to help individuals with low sensitivity, such as children, elderly or neuropathic, to choose the shoes that fit the best.

Compression for the management of venous leg ulcers: which material do we have?

PubMed

Partsch, Hugo

2014-05-01

Compression therapy is the most important basic treatment modality in venous leg ulcers. The review focusses on the materials which are used: 1. Compression bandages, 2. Compression stockings, 3. Self-adjustable Velcro-devices, 4. Compression pumps, 5. Hybrid devices. Compression bandages, usually applied by trained staff, provide a wide spectrum of materials with different elastic properties. To make bandaging easier, safer and more effective, most modern bandages combine different material components. Self-management of venous ulcers has become feasible by introducing double compression stockings ("ulcer kits") and self-adjustable Velcro devices. Compression pumps can be used as adjunctive measures, especially for patients with restricted mobility. The combination of sustained and intermittent compression ("hybrid device") is a promising new tool. The interface pressure corresponding to the dosage of compression therapy determines the hemodynamic efficacy of each device. In order to reduce ambulatory venous hypertension compression pressures of more than 50 mm Hg in the upright position are desirable. At the same time pressure should be lower in the resting position in order to be tolerated. This prerequisite may be fulfilled by using inelastic, short stretch material including multicomponent bandages and cohesive surfaces, all characterized by high stiffness. Such materials do not give way when calf muscles contract during walking which leads to high peaks of interface pressure ("massaging effect"). © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Evaluation of three different devices to reduce stasis edema in poorly mobile nursing home patients.

PubMed

Benigni, Jean-Patrick; Uhl, Jean-François; Balet, Florence; Filori, Pascal; Chahim, Maxime

2018-03-08

Prolonged immobility in the sitting position in the elderly is known to produce venous stasis with leg edema and possible skin changes. Compression stockings are often applied for this clinical problem. There are few experienced nursing staff available to supervise the difficult task of stocking application. The authors have researched other effective and simple devices that may be suitable alternatives. This article reports the results of three different devices to reduce leg edema, as measured by reduction in leg volume : an electro- stimulation device, an adjustable compression Velcro® wrap and a short stretch bandage, each tested over a two-hour period. In this randomized pilot study including 38 patients, the authors observed no difference in leg volume following electro-stimulation (Veinoplus®). They noted a significant reduction in leg volume following use of the other two devices, more with the adjustable Velcro® wrap compression (Circaid Juxtafit®) than with the short stretch bandage (Rosidal K®). Measurement of the interface pressures created by these two devices and also assessing the stiffness created by applying each device for two hours confirm that pressure is more important than stiffness in the reduction of edema in these particular patients. This pilot study is to be added to the results of previous published studies showing the efficacy in reducting leg edema of Velcro® adjustable compression wrap and its ease of use.

Microfluidic diffusion diluter: bulging of PDMS microchannels under pressure-driven flow

NASA Astrophysics Data System (ADS)

Holden, Matthew A.; Kumar, Saurabh; Beskok, Ali; Cremer, Paul S.

2003-05-01

The bulging of microfluidic systems during pressure-driven flow is potentially a major consideration for polydimethylsiloxane (PDMS)-based devices. Microchannel cross-sectional areas can change drastically as a function of flow rate and downstream microchannel position. Such geometrical flexibility leads to difficulties in predicting convective/diffusive transport for these systems. We have previously introduced a non-dimensional parameter, kappa, for characterizing convection and diffusion behavior for pressure-driven flow in rigid all-glass systems. This paper describes a modification of that concept for application to non-rigid systems, which is accomplished by incorporating an experimental step to account for the bulging in PDMS/glass microsystems. Specifically, an experimental measurement of channel height by fluorescence microscopy is combined with the aforementioned theory to characterize convective/diffusive behavior at a single location in the device. This allowed the parameter kappa to be determined at that point and applied to predict fluid flow in the subsequent portion of the PDMS microsystem. This procedure was applied to a PDMS/glass microfluidic diffusion dilution (muDD) device designed for generating concentration gradients. Theoretically predicted and experimentally measured distributions of concentrations within the microsystem matched well.

Characterization of size-dependent mechanical properties of tip-growing cells using a lab-on-chip device.

PubMed

Hu, Chengzhi; Munglani, Gautam; Vogler, Hannes; Ndinyanka Fabrice, Tohnyui; Shamsudhin, Naveen; Wittel, Falk K; Ringli, Christoph; Grossniklaus, Ueli; Herrmann, Hans J; Nelson, Bradley J

2016-12-20

Quantification of mechanical properties of tissues, living cells, and cellular components is crucial for the modeling of plant developmental processes such as mechanotransduction. Pollen tubes are tip-growing cells that provide an ideal system to study the mechanical properties at the single cell level. In this article, a lab-on-a-chip (LOC) device is developed to quantitatively measure the biomechanical properties of lily (Lilium longiflorum) pollen tubes. A single pollen tube is fixed inside the microfluidic chip at a specific orientation and subjected to compression by a soft membrane. By comparing the deformation of the pollen tube at a given external load (compressibility) and the effect of turgor pressure on the tube diameter (stretch ratio) with finite element modeling, its mechanical properties are determined. The turgor pressure and wall stiffness of the pollen tubes are found to decrease considerably with increasing initial diameter of the pollen tubes. This observation supports the hypothesis that tip-growth is regulated by a delicate balance between turgor pressure and wall stiffness. The LOC device is modular and adaptable to a variety of cells that exhibit tip-growth, allowing for the straightforward measurement of mechanical properties.

Portable device and method for determining permeability characteristics of earth formations

DOEpatents

Shuck, Lowell Z.

1977-01-01

The invention is directed to a device which is used for determining permeability characteristics of earth formations at the surface thereof. The determination of the maximum permeability direction and the magnitude of permeability are achieved by employing a device comprising a housing having a central fluid-injection port surrounded by a plurality of spaced-apart fluid flow and pressure monitoring ports radially extending from the central injection port. With the housing resting on the earth formation in a relatively fluid-tight manner as provided by an elastomeric pad disposed therebetween, fluid is injected through the central port into the earth formation and into registry with the fluid-monitoring ports disposed about the injection port. The fluid-monitoring ports are selectively opened and the flow of the fluid through the various fluid ports is measured so as to provide a measurement of flow rates and pressure distribution about the center hole which is indicative on the earth formation permeability direction and magnitude. For example, the azimuthal direction of the fluid-monitoring ports in the direction through which the greatest amount of injected fluid flows as determined by the lowest pressure distribution corresponds to the direction of maximum permeability in the earth formation.

Rugged, no-moving-parts windspeed and static pressure probe designs for measurements in planetary atmospheres

NASA Technical Reports Server (NTRS)

Bedard, A. J., Jr.; Nishiyama, R. T.

1993-01-01

Instruments developed for making meteorological observations under adverse conditions on Earth can be applied to systems designed for other planetary atmospheres. Specifically, a wind sensor developed for making measurements within tornados is capable of detecting induced pressure differences proportional to wind speed. Adding strain gauges to the sensor would provide wind direction. The device can be constructed in a rugged form for measuring high wind speeds in the presence of blowing dust that would clog bearings and plug passages of conventional wind speed sensors. Sensing static pressure in the lower boundary layer required development of an omnidirectional, tilt-insensitive static pressure probe. The probe provides pressure inputs to a sensor with minimum error and is inherently weather-protected. The wind sensor and static pressure probes have been used in a variety of field programs and can be adapted for use in different planetary atmospheres.

A point of application study to determine the accuracy, precision and reliability of a low-cost balance plate for center of pressure measurement.

PubMed

Goble, Daniel J; Khan, Ehran; Baweja, Harsimran S; O'Connor, Shawn M

2018-04-11

Changes in postural sway measured via force plate center of pressure have been associated with many aspects of human motor ability. A previous study validated the accuracy and precision of a relatively new, low-cost and portable force plate called the Balance Tracking System (BTrackS). This work compared a laboratory-grade force plate versus BTrackS during human-like dynamic sway conditions generated by an inverted pendulum device. The present study sought to extend previous validation attempts for BTrackS using a more traditional point of application (POA) approach. Computer numerical control (CNC) guided application of ∼155 N of force was applied five times to each of 21 points on five different BTrackS Balance Plate (BBP) devices with a hex-nose plunger. Results showed excellent agreement (ICC > 0.999) between the POAs and measured COP by the BBP devices, as well as high accuracy (<1% average percent error) and precision (<0.1 cm average standard deviation of residuals). The ICC between BBP devices was exceptionally high (ICC > 0.999) providing evidence of almost perfect inter-device reliability. Taken together, these results provide an important, static corollary to the previously obtained dynamic COP results from inverted pendulum testing of the BBP. Copyright © 2018 Elsevier Ltd. All rights reserved.

21 CFR 870.1140 - Venous blood pressure manometer.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Venous blood pressure manometer. 870.1140 Section... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1140 Venous blood pressure manometer. (a) Identification. A venous blood pressure manometer is a device attached to a venous...

21 CFR 870.1140 - Venous blood pressure manometer.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Venous blood pressure manometer. 870.1140 Section... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1140 Venous blood pressure manometer. (a) Identification. A venous blood pressure manometer is a device attached to a venous...

21 CFR 870.1120 - Blood pressure cuff.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Blood pressure cuff. 870.1120 Section 870.1120...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1120 Blood pressure cuff. (a) Identification. A blood pressure cuff is a device that has an inflatable bladder in an inelastic...

21 CFR 870.1140 - Venous blood pressure manometer.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Venous blood pressure manometer. 870.1140 Section... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1140 Venous blood pressure manometer. (a) Identification. A venous blood pressure manometer is a device attached to a venous...

21 CFR 870.1120 - Blood pressure cuff.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Blood pressure cuff. 870.1120 Section 870.1120...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1120 Blood pressure cuff. (a) Identification. A blood pressure cuff is a device that has an inflatable bladder in an inelastic...

21 CFR 870.1120 - Blood pressure cuff.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Blood pressure cuff. 870.1120 Section 870.1120...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1120 Blood pressure cuff. (a) Identification. A blood pressure cuff is a device that has an inflatable bladder in an inelastic...

21 CFR 870.1120 - Blood pressure cuff.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Blood pressure cuff. 870.1120 Section 870.1120...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1120 Blood pressure cuff. (a) Identification. A blood pressure cuff is a device that has an inflatable bladder in an inelastic...

21 CFR 870.1140 - Venous blood pressure manometer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Venous blood pressure manometer. 870.1140 Section... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Diagnostic Devices § 870.1140 Venous blood pressure manometer. (a) Identification. A venous blood pressure manometer is a device attached to a venous...

40 CFR 63.1010 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

Code of Federal Regulations, 2012 CFR

2012-07-01

... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... heavy liquid service; pressure relief devices in light liquid or heavy liquid service; and...

40 CFR 63.1010 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

Code of Federal Regulations, 2014 CFR

2014-07-01

... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... heavy liquid service; pressure relief devices in light liquid or heavy liquid service; and...

40 CFR 63.1010 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

Code of Federal Regulations, 2013 CFR

2013-07-01

... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... heavy liquid service; pressure relief devices in light liquid or heavy liquid service; and...

40 CFR 63.1010 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

Code of Federal Regulations, 2010 CFR

2010-07-01

... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... heavy liquid service; pressure relief devices in light liquid or heavy liquid service; and...

Cryogenic System for Neutron Scattering Experiments with In Situ Pressure Tuning Mechanism: Response of the Antiferromagnetism of URu2Si2 to Uniaxial Stress

NASA Astrophysics Data System (ADS)

Kawarazaki, Shuzo; Uwatoko, Yoshiya; Yokoyama, Makoto; Okita, Yuji; Tabata, Yoshikazu; Taniguchi, Toshifumi; Amitsuka, Hiroshi

2002-10-01

A handy insertable device to manipulate hydrostatic pressure or uniaxial stress on a sample in a cryostat for neutron scattering experiments is described. The pressure that is generated in a miniature hydraulic oil-cylinder on the top of the inserting stick is transmitted to the sample via a long piston-cylinder unit made of a thick stainless-steel tube and a fiber-reinforced plastics (FRP) rod. One can thus in situ tune the pressure or the stress on the sample without handling the pressure-cell at room temperature outside the cryostat. The device is designed to fit into the ILL-type Orange cryostat so that it can be used in many neutron scattering facilities. A newly designed uniaxial-stress cell and hydrostatic pressure cell to be used with this system are also described. The result of measurement of the hysteresis effect of uniaxial stress on the antiferromagnetism of URu2Si2 at 1.4 K is presented.

Noninvasive estimation of assist pressure for direct mechanical ventricular actuation

NASA Astrophysics Data System (ADS)

An, Dawei; Yang, Ming; Gu, Xiaotong; Meng, Fan; Yang, Tianyue; Lin, Shujing

2018-02-01

Direct mechanical ventricular actuation is effective to reestablish the ventricular function with non-blood contact. Due to the energy loss within the driveline of the direct cardiac compression device, it is necessary to acquire the accurate value of assist pressure acting on the heart surface. To avoid myocardial trauma induced by invasive sensors, the noninvasive estimation method is developed and the experimental device is designed to measure the sample data for fitting the estimation models. By examining the goodness of fit numerically and graphically, the polynomial model presents the best behavior among the four alternative models. Meanwhile, to verify the effect of the noninvasive estimation, the simplified lumped parameter model is utilized to calculate the pre-support and the post-support left ventricular pressure. Furthermore, by adjusting the driving pressure beyond the range of the sample data, the assist pressure is estimated with the similar waveform and the post-support left ventricular pressure approaches the value of the adult healthy heart, indicating the good generalization ability of the noninvasive estimation method.

Air elimination capability in rapid infusion systems.

PubMed

Zoremba, N; Gruenewald, C; Zoremba, M; Rossaint, R; Schaelte, G

2011-11-01

Pressure infusion devices are used in clinical practice to apply large volumes of fluid over a short period of time. Although air infusion is a major complication, they have limited capability to detect and remove air during pressure infusion. In this investigation, we tested the air elimination capabilities of the Fluido(®) (The Surgical Company), Level 1(®) (Level 1 Technologies Inc.) and Ranger(®) (Augustine Medical GmbH) pressure infusion devices. Measurements were undertaken with a crystalloid solution during an infusion flow of 100, 200, 400 and 800 ml.min(-1). Four different volumes of air (25, 50, 100 and 200 ml) were injected as boluses in one experimental setting, or infused continuously over the time needed to perfuse 2 l saline in the other setting. The perfusion fluid was collected in an airtight infusion bag and the amount of air obtained in the bag was measured. The delivered air volume was negligible and would not cause any significant air embolism in all experiments. In our experimental setting, we found, during high flow, an increased amount of uneliminated air in all used devices compared with lower perfusion flows. All tested devices had a good air elimination capability. The use of ultrasonic air detection coupled with an automatic shutoff is a significant safety improvement and can reliably prevent accidental air embolism at rapid flows. © 2011 The Authors. Anaesthesia © 2011 The Association of Anaesthetists of Great Britain and Ireland.

Ocular perfusion pressure control during pars plana vitrectomy: testing a novel device.

PubMed

Rossi, Tommaso; Querzoli, Giorgio; Gelso, Aldo; Angelini, Giampiero; Rossi, Alessandro; Corazza, Paolo; Landi, Laura; Telani, Serena; Ripandelli, Guido

2017-12-01

To study the efficacy of a novel device intended to control infusion pressure based on mean ocular perfusion pressure (MOPP) during pars plana vitrectomy (PPV). An arm blood pressure cuff connected to a vitrectomy machine calculated mean arterial pressure (MAP), while a pressure sensor close to the infusion trocar measured intraocular pressure (IOP). MOPP was calculated in real time in 36 consecutive patients undergoing PPV, who were divided into two groups. The device lowered IOP every time that calculated MOPP fell below 30 mmHg in the Control ON group (18 patients), while no action was taken in the Control OFF group (18 patients). Baseline IOP and blood pressure were similar between groups. The Control ON group had significantly lower average intraoperative IOP (30.5 ± 2.1 vs. 35.9 ± 6.9 mmHg; p = 0.002) and higher MOPP (56.4 ± 5.9 vs. 49.7 ± 6.1 mmHg) than the Control OFF group. The Control ON group also spent less time at MOPP < 10 mmHg and < 30 mmHg: 0 vs. 3.40 ± 2.38 min (p < 0.001) and 9.91 ± 7.15 vs. 16.13 ± 8.12 min (p = 0.02), respectively. The MOPP control device effectively maintained lower IOP and higher MOPP throughout surgery. It also helped avoid dangerous IOP peaks and MOPP dips, allowing patients to spend less time at MOPP of < 10 and < 30 mmHg.

Prototype of haptic device for sole of foot using magnetic field sensitive elastomer

NASA Astrophysics Data System (ADS)

Kikuchi, T.; Masuda, Y.; Sugiyama, M.; Mitsumata, T.; Ohori, S.

2013-02-01

Walking is one of the most popular activities and a healthy aerobic exercise for the elderly. However, if they have physical and / or cognitive disabilities, sometimes it is challenging to go somewhere they don't know well. The final goal of this study is to develop a virtual reality walking system that allows users to walk in virtual worlds fabricated with computer graphics. We focus on a haptic device that can perform various plantar pressures on users' soles of feet as an additional sense in the virtual reality walking. In this study, we discuss a use of a magnetic field sensitive elastomer (MSE) as a working material for the haptic interface on the sole. The first prototype with MSE was developed and evaluated in this work. According to the measurement of planter pressures, it was found that this device can perform different pressures on the sole of a light-weight user by applying magnetic field on the MSE. The result also implied necessities of the improvement of the magnetic circuit and the basic structure of the mechanism of the device.

Light-modulating pressure sensor with integrated flexible organic light-emitting diode.

PubMed

Cheneler, D; Vervaeke, M; Thienpont, H

2014-05-01

Organic light-emitting diodes (OLEDs) are used almost exclusively for display purposes. Even when implemented as a sensing component, it is rarely in a manner that exploits the possible compliance of the OLED. Here it is shown that OLEDs can be integrated into compliant mechanical micro-devices making a new range of applications possible. A light-modulating pressure sensor is considered, whereby the OLED is integrated with a silicon membrane. It is shown that such devices have potential and advantages over current measurement techniques. An analytical model has been developed that calculates the response of the device. Ray tracing numerical simulations verify the theory and show that the design can be optimized to maximize the resolution of the sensor.

Evaluation of Pressure Generated by Resistors From Different Positive Expiratory Pressure Devices.

PubMed

Fagevik Olsén, Monika; Carlsson, Maria; Olsén, Erik; Westerdahl, Elisabeth

2015-10-01

Breathing exercises with positive expiratory pressure (PEP) are used to improve pulmonary function and airway clearance. Different PEP devices are available, but there have been no studies that describe the pressure generated by different resistors. The purpose of this study was to compare pressures generated from the proprietary resistor components of 4 commercial flow-dependent PEP valves with all other parameters kept constant. Resistors from 4 flow-regulated PEP devices (Pep/Rmt system, Wellspect HealthCare; Pipe P breathing exerciser, Koo Medical Equipment; Mini-PEP, Philips Respironics [including resistors by Rüsch]; and 15-mm endo-adapter, VBM Medizintechnik) were tested randomly by a blinded tester at constant flows of 10 and 18 L/min from an external gas system. All resistors were tested 3 times. Resistors with a similar diameter produced statistically significant different pressures at the same flow. The differences were smaller when the flow was 10 L/min compared with 18 L/min. The differences were also smaller when the diameter of the resistor was increased. The pressures produced by the 4 resistors of the same size were all significantly different when measuring 1.5- and 2.0-mm resistors at a flow of 10 L/min and 2.0-mm resistors at a flow of 18 L/min (P < .001). There were no significant differences between any of the resistors when testing sizes of 4.5 and 5.0 mm at either flow. The Mini-PEP and adapter resistors gave the highest pressures. Pressures generated by the different proprietary resistor components of 4 commercial PEP devices were not comparable, even though the diameter of the resistors is reported to be the same. The pressures generated were significantly different, particularly when using small-diameter resistors at a high flow. Therefore, the resistors may not be interchangeable. This is important information for clinicians, particularly when considering PEP for patients who do not tolerate higher pressures. Copyright © 2015 by Daedalus Enterprises.

Stand Alone Pressure Measurement Device (SAPMD) for the space shuttle Orbiter, part 1

NASA Technical Reports Server (NTRS)

Tomlinson, Bill

1989-01-01

The specifications for the Stand Alone Pressure Measurement Device (SAPMD) are as follows: the SAPMD shall measure ambient pressure at the surface of the Orbiter TPS in the range of 0 to 15 pounds per square inch absolute (PSIA). Measurement will begin at solid rocket booster (SRB) ignition as sensed by appropriate vibration sensing elements in the SAPMD. Pressure and corresponding real-time data are to be recorded every one tenth second for 140 seconds and at the end of the recording period, the operation will be discontinued with the data preserved for interrogation subsequent to Orbiter re-entry and landing. The type and size of the battery shall be such as to allow the vibration sensing elements and a real-time clock to be initialized a minimum of 30 day prior to launch and still provide power as necessary to perform the 140 second data recording period after SRB ignition. Battery installation shall be in such a manner as to allow battery replacement without removing the SAPMD from its position or removing more than one TPS tile. The SAPMD must be mounted in specific locations under tile of the TPS. To accommodate such mounting, the absolute maximum physical dimensions much not exceed 6.0 inches in length, 1.5 inches in width, and 0.4 inches in height, and the device shall be of such configuration that it can be bonded to the Orbiter skin at the joint line of two TPS tiles with the pressure sensing port at the surface of the tile. The SAPMD must remain operational in the temperature range of -40 to +85 C and survive storage temperature of -55 to +125 C. The pressure port must withstand 934 C without causing damage to the TPS during entry and must remain functional at 262 C during ascent. The accuracy of the pressure measurement must be plus or minus one-half PSIA over a temperature range of 0 to +36 C. All the specifications were met and verified by prototype testing and documented in the enclosed test data. Four flight-qualified models were fabricated and of these, two were delivered and successfully flown in the cargo bay of STS-26.

Pressure-Velocity Correlations in the Cove of a Leading Edge Slat

NASA Astrophysics Data System (ADS)

Wilkins, Stephen; Richard, Patrick; Hall, Joseph

2015-11-01

One of the major sources of aircraft airframe noise is related to the deployment of high-lift devices, such as leading-edge slats, particularly when the aircraft is preparing to land. As the engines are throttled back, the noise produced by the airframe itself is of great concern, as the aircraft is low enough for the noise to impact civilian populations. In order to reduce the aeroacoustic noise sources associated with these high lift devices for the next generation of aircraft an experimental investigation of the correlation between multi-point surface-mounted fluctuating pressures measured via flush-mounted microphones and the simultaneously measured two-component velocity field measured via Particle Image Velocimetry (PIV) is studied. The development of the resulting shear-layer within the slat cove is studied for Re =80,000, based on the wing chord. For low Mach number flows in air, the major acoustic source is a dipole acoustic source tied to fluctuating surface pressures on solid boundaries, such as the underside of the slat itself. Regions of high correlations between the pressure and velocity field near the surface will likely indicate a strong acoustic dipole source. In order to study the underlying physical mechanisms and understand their role in the development of aeroacoustic noise, Proper Orthogonal Decomposition (POD) by the method of snapshots is employed on the velocity field. The correlation between low-order reconstructions and the surface-pressure measurements are also studied.

Accuracy of continuous noninvasive arterial pressure monitoring in living-liver donors during transplantation.

PubMed

Araz, Coskun; Zeyneloglu, Pinar; Pirat, Arash; Veziroglu, Nukhet; Camkiran Firat, Aynur; Arslan, Gulnaz

2015-04-01

Hemodynamic monitoring is vital during liver transplant surgeries because distinct hemodynamic changes are expected. The continuous noninvasive arterial pressure (CNAP) monitor is a noninvasive device for continuous arterial pressure measurement by a tonometric method. This study compared continuous noninvasive arterial pressure monitoring with invasive direct arterial pressure monitoring in living-liver donors during transplant. There were 40 patients analyzed while undergoing hepatic lobectomy for liver transplant. Invasive pressure monitoring was established at the radial artery and continuous noninvasive arterial pressure monitoring using a finger sensor was recorded simultaneously from the contralateral arm. Systolic, diastolic, and mean arterial pressures from the 2 methods were compared. Correlation between the 2 methods was calculated. A total of 5433 simultaneous measurements were obtained. For systolic arterial blood pressure, 55% continuous noninvasive arterial pressure measurements were within 10% direct arterial measurement; the correlation was 0.479, continuous noninvasive arterial pressure bias was -0.3 mm Hg, and limits of agreement were 32.0 mm Hg. For diastolic arterial blood pressure, 50% continuous noninvasive arterial pressure measurements were within 10% direct arterial measurement; the correlation was 0.630, continuous noninvasive arterial pressure bias was -0.4 mm Hg, and limits of agreement were 21.1 mm Hg. For mean arterial blood pressure, 60% continuous noninvasive arterial pressure measurements were within 10% direct arterial measurement; the correlation was 0.692, continuous noninvasive arterial pressure bias was +0.4 mm Hg, and limits of agreement were 20.8 mm Hg. The 2 monitoring techniques did not show acceptable agreement. Our results suggest that continuous noninvasive arterial pressure monitoring is not equivalent to invasive arterial pressure monitoring in donors during living-donor liver transplant.

A Novel Intraurethral Device Diagnostic Index to Classify Bladder Outlet Obstruction in Men with Lower Urinary Tract Symptoms

PubMed Central

Reis, Leonardo O.; Barreiro, Guilherme C.; Prudente, Alessandro; Silva, Cleide M.; Bassani, José W. M.; D'Ancona, Carlos A. L.

2009-01-01

Objectives. Using a urethral device at the fossa navicularis, bladder pressure during voiding can be estimated by a minimal invasive technique. This study purposes a new diagnostic index for patients with lower urinary tract symptoms (LUTSs). Methods. Fifty one patients presenting with LUTSs were submitted to a conventional urodynamic and a minimal invasive study. The results obtained through the urethral device and invasive classic urodynamics were compared. The existing bladder outlet obstruction index (BOOI) equation that classifies men with LUTSs was modified to allow minimal invasive measurement of isovolumetric bladder pressure in place of detrusor pressure at maximum urine flow. Accuracy of the new equation for classifying obstruction was then tested in this group of men. Results. The modified equation identified men with obstruction with a positive predictive value of 68% and a negative predictive value of 70%, with an overall accuracy of 70%. Conclusions. The proposed equation can accurately classify over 70% of men without resorting to invasive pressure flow studies. We must now evaluate the usefulness of this classification for the surgical treatment of men with LUTSs. PMID:19125194

A New Cuffless Device for Measuring Blood Pressure: A Real-Life Validation Study.

PubMed

Schoot, Tessa S; Weenk, Mariska; van de Belt, Tom H; Engelen, Lucien J L P G; van Goor, Harry; Bredie, Sebastian J H

2016-05-05

Cuffless blood pressure (BP) monitoring devices, based on pulse transit time, are being developed as an easy-to-use, more convenient, fast, and relatively cheap alternative to conventional BP measuring devices based on cuff occlusion. Thereby they may provide a great alternative to BP self-measurement. The objective of our study was to evaluate the performance of the first release of the Checkme Health Monitor (Viatom Technology), a cuffless BP monitor, in a real-life setting. Furthermore, we wanted to investigate whether the posture of the volunteer and the position of the device relative to the heart level would influence its outcomes. Study volunteers fell into 3 BP ranges: high (>160 mmHg), normal (130-160 mmHg), and low (<130 mmHg). All requirements for test environment, observer qualification, volunteer recruitment, and BP measurements were met according to the European Society of Hypertension International Protocol (ESH-IP) for the validation of BP measurement devices. After calibrating the Checkme device, we measured systolic BP with Checkme and a validated, oscillometric reference BP monitor (RM). Measurements were performed in randomized order both in supine and in sitting position, and with Checkme at and above heart level. We recruited 52 volunteers, of whom we excluded 15 (12 due to calibration failure with Checkme, 3 due to a variety of reasons). The remaining 37 volunteers were divided into low (n=14), medium (n=13), and high (n=10) BP ranges. There were 18 men and 19 women, with a mean age of 54.1 (SD 14.5) years, and mean recruitment systolic BP of 141.7 (SD 24.7) mmHg. BP results obtained by RM and Checkme correlated well. In the supine position, the difference between the RM and Checkme was >5 mmHg in 17 of 37 volunteers (46%), of whom 9 of 37 (24%) had a difference >10 mmHg and 5 of 37 (14%) had a difference >15 mmHg. BP obtained with Checkme correlated well with RM BP, particularly in the position (supine) in which the device was calibrated. These preliminary results are promising for conducting further research on cuffless BP measurement in the clinical and outpatient settings.

Sensing and Storing the Blood Pressure Measure by Patients through A Platform and Mobile Devices †.

PubMed

Villarreal, Vladimir; Nielsen, Mel; Samudio, Manuel

2018-06-03

In this article, we present a platform that allows for the integration of different applications for the follow-up of patients with chronic diseases. We developed two elements: a mobile and a web application. The mobile application allows the capture and processing of vital signs for patients with high blood pressure (hypertension). This application allows for the patient to store the data obtained, provides historical information and trends of the stored measures, and provides alerts and recommendations according to ranges of measures that were obtained. The web application allows the doctor and patients to obtain updated information of the disease behavior through the measures obtained. We used different biometric devices including an efimomanometer, glucometer, scale, and a thermometer with a wi-fi connection. Through this web application, we also generated information about average measures at a given time, by age, by region, and by a specific date. The developed system was evaluated in a medical center with different types of patients.

Measurement of Blood Pressure Using an Arterial Pulsimeter Equipped with a Hall Device

PubMed Central

Lee, Sang-Suk; Nam, Dong-Hyun; Hong, You-Sik; Lee, Woo-Beom; Son, Il-Ho; Kim, Keun-Ho; Choi, Jong-Gu

2011-01-01

To measure precise blood pressure (BP) and pulse rate without using a cuff, we have developed an arterial pulsimeter consisting of a small, portable apparatus incorporating a Hall device. Regression analysis of the pulse wave measured during testing of the arterial pulsimeter was conducted using two equations of the BP algorithm. The estimated values of BP obtained by the cuffless arterial pulsimeter over 5 s were compared with values obtained using electronic or liquid mercury BP meters. The standard deviation between the estimated values and the measured values for systolic and diastolic BP were 8.3 and 4.9, respectively, which are close to the range of values of the BP International Standard. Detailed analysis of the pulse wave measured by the cuffless radial artery pulsimeter by detecting changes in the magnetic field can be used to develop a new diagnostic algorithm for BP, which can be applied to new medical apparatus such as the radial artery pulsimeter. PMID:22319381

A Novel Intracranial Pressure Readout Circuit for Passive Wireless LC Sensor.

PubMed

Wang, Fa; Zhang, Xuan; Shokoueinejad, Mehdi; Iskandar, Bermans J; Medow, Joshua E; Webster, John G

2017-10-01

We present a wide frequency range, low cost, wireless intracranial pressure monitoring system, which includes an implantable passive sensor and an external reader. The passive sensor consists of two spiral coils and transduces the pressure change to a resonant frequency shift. The external portable reader reads out the sensor's resonant frequency over a wide frequency range (35 MHz-2.7 GHz). We propose a novel circuit topology, which tracks the system's impedance and phase change at a high frequency with low-cost components. This circuit is very simple and reliable. A prototype has been developed, and measurement results demonstrate that the device achieves a suitable measurement distance (>2 cm), sufficient sample frequency (>6 Hz), fine resolution, and good measurement accuracy for medical practice. Responsivity of this prototype is 0.92 MHz/mmHg and resolution is 0.028 mmHg. COMSOL specific absorption rate simulation proves that this system is safe. Considerations to improve the device performance have been discussed, which include the size of antenna, the power radiation, the Analog-to-digital converter (ADC) choice, and the signal processing algorithm.

CCFP Analyzer

NASA Image and Video Library

2016-05-06

ISS047e106715 (05/06/2016) --- ESA (European Space Agency astronaut Tim Peake unpacks a cerebral and cochlear fluid pressure (CCFP) analyzer. The device is being tested to measure the pressure of the fluid in the skull, also known as intracranial pressure, which may increase due to fluid shifts in the body while in microgravity. It is hypothesized that the headward fluid shift that occurs during space flight leads to increased pressure in the brain, which may push on the back of the eye, causing it to change shape.

Modelflow Estimates of Stroke Volume Do Not Correlate With Doppler Ultrasound Estimates During Upright Posture

NASA Technical Reports Server (NTRS)

Ferguson, Connor R.; Lee, Stuart M. C.; Stenger, Michael B.; Platts, Steven H.; Laurie, Steven S.

2014-01-01

Orthostatic intolerance affects 60-80% of astronauts returning from long-duration missions, representing a significant risk to completing mission-critical tasks. While likely multifactorial, a reduction in stroke volume (SV) represents one factor contributing to orthostatic intolerance during stand and head up tilt (HUT) tests. Current measures of SV during stand or HUT tests use Doppler ultrasound and require a trained operator and specialized equipment, restricting its use in the field. BeatScope (Finapres Medical Systems BV, The Netherlands) uses a modelflow algorithm to estimate SV from continuous blood pressure waveforms in supine subjects; however, evidence supporting the use of Modelflow to estimate SV in subjects completing stand or HUT tests remain scarce. Furthermore, because the blood pressure device is held extended at heart level during HUT tests, but allowed to rest at the side during stand tests, changes in the finger arterial pressure waveform resulting from arm positioning could alter modelflow estimated SV. The purpose of this project was to compare Doppler ultrasound and BeatScope estimations of SV to determine if BeatScope can be used during stand or HUT tests. Finger photoplethysmography was used to acquire arterial pressure waveforms corrected for hydrostatic finger-to-heart height using the Finometer (FM) and Portapres (PP) arterial pressure devices in 10 subjects (5 men and 5 women) during a stand test while simultaneous estimates of SV were collected using Doppler ultrasound. Measures were made after 5 minutes of supine rest and while subjects stood for 5 minutes. Next, SV estimates were reacquired while each arm was independently raised to heart level, a position similar to tilt testing. Supine SV estimates were not significantly different between all three devices (FM: 68+/-20, PP: 71+/-21, US: 73+/-21 ml/beat). Upon standing, the change in SV estimated by FM (-18+/-8 ml) was not different from PP (-21+/-12), but both were significantly less than US (-37+/-16 ml, p<.05). Raising finger BP devices to heart level caused no significant change in SV measured with any of the devices (FM: 1.5+/-19, PP: 1.7+/-26, US: 0.5+/-6), although variability was 3-6x greater as assessed by both blood pressure devices compared to US. Retrospective analysis of blood pressure data to assess SV in 11 supine subjects revealed significantly different estimates between methods (FM: 95+/-17, US: 75+/-32, p<.05), but the change in SV resulting from HUT was similar between methods (FM: -37+/-9, US: -40+/-18 ml). However, the correlation coefficient determined from pairs of SV estimated by US and FM was weak (r2=0.03). These data suggest Modelflow cannot be used in lieu of Doppler ultrasound to estimate SV during stand or HUT tests. Further investigation should focus on identifying factors contributing to differences between these measurement techniques in order to make use of a simple method for assessing beat-by-beat changes in SV during postural changes, especially during field testing.

Method for the measurement of forest duff moisture content

Treesearch

Peter R. Robichaud; Roger D. Hungerford; David S. Gasvoda

2000-01-01

An apparatus and method for the moisture content measurement of compressible materials using pressure to firmly hold surface probes against the material to be measured. The apparatus uses moisture measurement circuitry employed in frequency domain impedance or time domain reflectometry devices to obtain moisture content readings from materials. These moisture content...

Apparatus and method for the measurement of forest duff moisture content

Treesearch

Peter R. Robichaud; Roger D. Hungerford; David S. Gasvoda

1999-01-01

An apparatus and method for the moisture content measurement of compressible materials using pressure to firmly hold surface probes against the marerial to be measured. The apparatus uses moisture measurement circuitry employed in frequency domain impedance or time domain reflectometry devices to obtain moisture content readings from materials. These moisture content...

40 CFR 63.1029 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

Code of Federal Regulations, 2014 CFR

2014-07-01

... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... in heavy liquid service; pressure relief devices in light liquid or heavy liquid service; and...

49 CFR 179.500-12 - Pressure relief devices.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure relief devices. 179.500-12 Section 179... Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of...

49 CFR 179.500-12 - Pressure relief devices.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure relief devices. 179.500-12 Section 179... Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of...

49 CFR 179.500-12 - Pressure relief devices.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure relief devices. 179.500-12 Section 179... Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of...

40 CFR 63.1029 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

Code of Federal Regulations, 2011 CFR

2011-07-01

... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... in heavy liquid service; pressure relief devices in light liquid or heavy liquid service; and...

40 CFR 63.1029 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

Code of Federal Regulations, 2013 CFR

2013-07-01

... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... in heavy liquid service; pressure relief devices in light liquid or heavy liquid service; and...

40 CFR 63.1029 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

Code of Federal Regulations, 2012 CFR

2012-07-01

... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... in heavy liquid service; pressure relief devices in light liquid or heavy liquid service; and...

49 CFR 179.500-12 - Pressure relief devices.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure relief devices. 179.500-12 Section 179... Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of...

21 CFR 868.2600 - Airway pressure monitor.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Airway pressure monitor. 868.2600 Section 868.2600 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2600 Airway pressure monitor. (a) Identification. An airway pressure monitor is a devic...

40 CFR 63.1029 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

Code of Federal Regulations, 2010 CFR

2010-07-01

... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... in heavy liquid service; pressure relief devices in light liquid or heavy liquid service; and...

21 CFR 890.5765 - Pressure-applying device.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pressure-applying device. 890.5765 Section 890.5765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5765 Pressure...

21 CFR 890.5765 - Pressure-applying device.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pressure-applying device. 890.5765 Section 890.5765 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices § 890.5765 Pressure...

Analysis of the separated boundary layer flow on the surface and in the wake of blunt trailing edge airfoils

NASA Technical Reports Server (NTRS)

Goradia, S. H.; Mehta, J. M.; Shrewsbury, G. S.

1977-01-01

The viscous flow phenomena associated with sharp and blunt trailing edge airfoils were investigated. Experimental measurements were obtained for a 17 percent thick, high performance GAW-1 airfoil. Experimental measurements consist of velocity and static pressure profiles which were obtained by the use of forward and reverse total pressure probes and disc type static pressure probes over the surface and in the wake of sharp and blunt trailing edge airfoils. Measurements of the upper surface boundary layer were obtained in both the attached and separated flow regions. In addition, static pressure data were acquired, and skin friction on the airfoil upper surface was measured with a specially constructed device. Comparison of the viscous flow data with data previously obtained elsewhere indicates reasonable agreement in the attached flow region. In the separated flow region, considerable differences exist between these two sets of measurements.

Fully wireless pressure sensor based on endoscopy images

NASA Astrophysics Data System (ADS)

Maeda, Yusaku; Mori, Hirohito; Nakagawa, Tomoaki; Takao, Hidekuni

2018-04-01

In this paper, the result of developing a fully wireless pressure sensor based on endoscopy images for an endoscopic surgery is reported for the first time. The sensor device has structural color with a nm-scale narrow gap, and the gap is changed by air pressure. The structural color of the sensor is acquired from camera images. Pressure detection can be realized with existing endoscope configurations only. The inner air pressure of the human body should be measured under flexible-endoscope operation using the sensor. Air pressure monitoring, has two important purposes. The first is to quantitatively measure tumor size under a constant air pressure for treatment selection. The second purpose is to prevent the endangerment of a patient due to over transmission of air. The developed sensor was evaluated, and the detection principle based on only endoscopy images has been successfully demonstrated.

Corpuls CPR Generates Higher Mean Arterial Pressure Than LUCAS II in a Pig Model of Cardiac Arrest.

PubMed

Eichhorn, S; Mendoza, A; Prinzing, A; Stroh, A; Xinghai, L; Polski, M; Heller, M; Lahm, H; Wolf, E; Lange, R; Krane, M

2017-01-01

According to the European Resuscitation Council guidelines, the use of mechanical chest compression devices is a reasonable alternative in situations where manual chest compression is impractical or compromises provider safety. The aim of this study is to compare the performance of a recently developed chest compression device (Corpuls CPR) with an established system (LUCAS II) in a pig model. Methods . Pigs ( n = 5/group) in provoked ventricular fibrillation were left untreated for 5 minutes, after which 15 min of cardiopulmonary resuscitation was performed with chest compressions. After 15 min, defibrillation was performed every 2 min if necessary, and up to 3 doses of adrenaline were given. If there was no return of spontaneous circulation after 25 min, the experiment was terminated. Coronary perfusion pressure, carotid blood flow, end-expiratory CO 2 , regional oxygen saturation by near infrared spectroscopy, blood gas, and local organ perfusion with fluorescent labelled microspheres were measured at baseline and during resuscitation. Results . Animals treated with Corpuls CPR had significantly higher mean arterial pressures during resuscitation, along with a detectable trend of greater carotid blood flow and organ perfusion. Conclusion . Chest compressions with the Corpuls CPR device generated significantly higher mean arterial pressures than compressions performed with the LUCAS II device.

Corpuls CPR Generates Higher Mean Arterial Pressure Than LUCAS II in a Pig Model of Cardiac Arrest

PubMed Central

Mendoza, A.; Prinzing, A.; Stroh, A.; Xinghai, L.; Polski, M.; Heller, M.; Lahm, H.; Wolf, E.; Lange, R.; Krane, M.

2017-01-01

According to the European Resuscitation Council guidelines, the use of mechanical chest compression devices is a reasonable alternative in situations where manual chest compression is impractical or compromises provider safety. The aim of this study is to compare the performance of a recently developed chest compression device (Corpuls CPR) with an established system (LUCAS II) in a pig model. Methods. Pigs (n = 5/group) in provoked ventricular fibrillation were left untreated for 5 minutes, after which 15 min of cardiopulmonary resuscitation was performed with chest compressions. After 15 min, defibrillation was performed every 2 min if necessary, and up to 3 doses of adrenaline were given. If there was no return of spontaneous circulation after 25 min, the experiment was terminated. Coronary perfusion pressure, carotid blood flow, end-expiratory CO2, regional oxygen saturation by near infrared spectroscopy, blood gas, and local organ perfusion with fluorescent labelled microspheres were measured at baseline and during resuscitation. Results. Animals treated with Corpuls CPR had significantly higher mean arterial pressures during resuscitation, along with a detectable trend of greater carotid blood flow and organ perfusion. Conclusion. Chest compressions with the Corpuls CPR device generated significantly higher mean arterial pressures than compressions performed with the LUCAS II device. PMID:29392137

Design of a Continuous Blood Pressure Measurement System Based on Pulse Wave and ECG Signals.

PubMed

Li, Jian-Qiang; Li, Rui; Chen, Zhuang-Zhuang; Deng, Gen-Qiang; Wang, Huihui; Mavromoustakis, Constandinos X; Song, Houbing; Ming, Zhong

2018-01-01

With increasingly fierce competition for jobs, the pressures on people have risen in recent years, leading to lifestyle and diet disorders that result in significantly higher risks of cardiovascular disease. Hypertension is one of the common chronic cardiovascular diseases; however, mainstream blood pressure measurement devices are relatively heavy. When multiple measurements are required, the user experience and the measurement results may be unsatisfactory. In this paper, we describe the design of a signal collection module that collects pulse waves and electrocardiograph (ECG) signals. The collected signals are input into a signal processing module to filter the noise and amplify the useful physiological signals. Then, we use a wavelet transform to eliminate baseline drift noise and detect the feature points of the pulse waves and ECG signals. We propose the concept of detecting the wave shape associated with an instance, an approach that minimizes the impact of atypical pulse waves on blood pressure measurements. Finally, we propose an improved method for measuring blood pressure based on pulse wave velocity that improves the accuracy of blood pressure measurements by 58%. Moreover, the results meet the american medical instrument promotion association standards, which demonstrate the feasibility of our measurement system.

Design of a Continuous Blood Pressure Measurement System Based on Pulse Wave and ECG Signals

PubMed Central

Li, Jian-Qiang; Li, Rui; Chen, Zhuang-Zhuang; Deng, Gen-Qiang; Wang, Huihui; Mavromoustakis, Constandinos X.; Ming, Zhong

2018-01-01

With increasingly fierce competition for jobs, the pressures on people have risen in recent years, leading to lifestyle and diet disorders that result in significantly higher risks of cardiovascular disease. Hypertension is one of the common chronic cardiovascular diseases; however, mainstream blood pressure measurement devices are relatively heavy. When multiple measurements are required, the user experience and the measurement results may be unsatisfactory. In this paper, we describe the design of a signal collection module that collects pulse waves and electrocardiograph (ECG) signals. The collected signals are input into a signal processing module to filter the noise and amplify the useful physiological signals. Then, we use a wavelet transform to eliminate baseline drift noise and detect the feature points of the pulse waves and ECG signals. We propose the concept of detecting the wave shape associated with an instance, an approach that minimizes the impact of atypical pulse waves on blood pressure measurements. Finally, we propose an improved method for measuring blood pressure based on pulse wave velocity that improves the accuracy of blood pressure measurements by 58%. Moreover, the results meet the american medical instrument promotion association standards, which demonstrate the feasibility of our measurement system. PMID:29541556

NaOH-based high temperature heat-of-fusion thermal energy storage device

NASA Technical Reports Server (NTRS)

Cohen, B. M.; Rice, R. E.

1978-01-01

A material called Thermkeep, developed as a low-cost method for the storage of thermal energy for solar electric power generating systems is discussed. The storage device consists of an insulated cylinder containing Thermkeep in which coiled tubular heat exchangers are immersed. A one-tenth scale model of the design contains 25 heat-exchanger tubes and 1500 kg of Thermkeep. Its instrumentation includes thermocouples to measure internal Thermkeep temperatures, vessel surface, heated shroud surface, and pressure gauges to indicate heat-exchanger pressure drops. The test-circuit design is presented and experimental results are discussed.

40 CFR 63.11585 - What are my notification, recordkeeping, and reporting requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... of the bag leak detector, parameter monitor, or CPMS. (ix) If a CPMS is used, the date of the latest...) Records of all inspections as required by § 63.11584(b) and pressure measurement device checks (if... according to § 63.11583(f). (viii) Records of particulate control device manufacturing specifications and...

Pressure beneath the Surface of a Fluid: Measuring the Correct Depth

ERIC Educational Resources Information Center

McCall, Richard P.

2013-01-01

Systematic errors can cause measurements to deviate from the actual value of the quantity being measured. Faulty equipment (such as a meterstick that is not marked correctly), inaccurate calibration of measuring devices (such as a scale to measure mass that has not been properly zeroed), and improper use of equipment by the experimenter (such as…

Clinical uses of in-shoe pressure analysis in podiatric sports medicine.

PubMed

Williams, Bruce E; Yakel, James D

2007-01-01

Athletic injuries of the foot and lower extremity are commonly treated with custom foot orthoses. These devices usually provide immediate relief of the athlete's pain and dysfunction. Occasionally, however, they do not help, or even increase the patient's discomfort. We discuss a method of using in-shoe pressure-measurement systems to analyze the athletic patient's foot and lower-extremity function before and after treatment with custom foot orthoses, with a focus on sagittal plane biomechanics. Case histories are presented of athletes whose gait pathologies were identified and treated successfully using an in-shoe pressure-measurement system.

Electronic-type vacuum gauges with replaceable elements

DOEpatents

Edwards, Jr., David

1984-01-01

In electronic devices for measuring pressures in vacuum systems, the metal elements which undergo thermal deterioration are made readily replaceable by making them parts of a simple plug-in unit. Thus, in ionization gauges, the filament and grid or electron collector are mounted on the novel plug-in unit. In thermocouple pressure gauges, the heater and attached thermocouple are mounted on the plug-in unit. Plug-in units have been designed to function, alternatively, as ionization gauge and as thermocouple gauge, thus providing new gauges capable of measuring broader pressure ranges than is possible with either an ionization gauge or a thermocouple gauge.

Does pressure matter in creating burns in a porcine model?

PubMed

Singer, Adam J; Taira, Breena R; Anderson, Ryon; McClain, Steve A; Rosenberg, Lior

2010-01-01

Multiple animal models of burn injury have been reported, and only some of these have been fully validated. One of the most popular approaches is burn infliction by direct contact with the heat source. Previous investigators have reported that the pressure of application of the contact burn infliction device does not affect the depth of injury. We hypothesized that the depth of injury would increase with increasing pressure of application in a porcine burn model. Forty mid-dermal contact burns measuring 25 x 25 mm were created on the back and flanks of an anesthetized domestic pig (50 kg) using a brass bar preheated in 80 degrees C water for a period of 30 or 20 seconds. The bars were applied using a spring-loaded device designed to control the amount of pressure applied to the skin. The pressures applied by the brass bar were gravity (0.2 kg), 2.0, 2.7, 3.8, and 4.5 kg in replicates of eight. One hour later, 8-mm full-thickness biopsies were obtained for histologic analysis using Elastic Van Gieson staining by a board-certified dermatopathologist masked to burn conditions. The depth of complete and partial collagen injury was measured from the level of the basement membrane using a microscopic micrometer measuring lens. Groups were compared with analysis of variance (ANOVA). The association between depth of injury and pressure was determined with Pearson correlations. The mean (95% confidence interval) depths of complete collagen injury with 30-second exposures were as follows: gravity only, 0.51 (0.39-0.66) mm; 2.0 kg, 0.72 (0.55-0.88) mm; 2.7 kg, 0.68 (0.55-1.00) mm; 3.8 kg, 0.92 (0.80-1.00) mm; and 4.5 kg, 1.65 (1.55-1.75) mm. The differences in depth of injury between the various pressure groups were significant (ANOVA, P < .001). The mean (95% confidence interval) depths of partial collagen injury were as follows: gravity only, 1.10 (0.92-1.30) mm; 2.0 kg, 1.46 (1.28-1.63) mm; 2.7 kg, 1.51 (1.34-1.64) mm; 3.8 kg, 1.82 (1.71-1.94) mm; and 4.5 kg, 2.50 (2.39-2.62) mm; and ANOVA, P = .001. The associations between pressure of application and depth of complete and partial collagen injury were 0.73 (P < .001) and 0.65 (P < .001), respectively. There is a direct association between the pressure of burn device application and depth of injury. Future studies should standardize and specify the amount of pressure applied using the burn infliction device.

Validation of the A&D UM-211 device for office blood pressure measurement according to the European Society of Hypertension International Protocol revision 2010.

PubMed

Fania, Claudio; Albertini, Federica; Palatini, Paolo

2017-10-01

The aim of this study was to define the accuracy of UM-211, an automated oscillometric device for office use coupled to several cuffs for different arm sizes, according to the International Protocol of the European Society of Hypertension. The validation was performed in 33 individuals. Their mean age was 59.6±12.9 years, systolic blood pressure (BP) was 144.3±21.5 mmHg (range: 96-184 mmHg), diastolic BP was 86.8±18.5 mmHg (range: 48-124 mmHg), and arm circumference was 30.2±4.3 cm (range: 23-39 cm). Four sequential readings were taken by observers 1 and 2 using a double-headed stethoscope and a mercury sphygmomanometer, whereas three BP readings were taken by the supervisor using the test instrument. The differences between the readings provided by the device and the mean observer measurements were calculated. Therefore, each device measurement was compared with the previous and the next mean observer measurement. The validation results fulfilled all the 2010 European Society of Hypertension revision Protocol criteria for the general population and passed all validation grades. On average, the device overestimated systolic BP by 1.7±2.4 mmHg and diastolic BP by 1.7±2.5 mmHg. These data show that the UM-211 device coupled to several cuffs for different ranges of arm circumference met the requirements for validation according to the International Protocol and can be recommended for clinical use in the adult population. However, these results mainly apply to the use of the 22-32 and the 31-45 cm cuffs.

Measurements of emission-propagation phenomena in low-energy atmospheric-pressure helium plasma

NASA Astrophysics Data System (ADS)

Yamada, Hiromasa; Shimizu, Tetsuji; Fujiwara, Masanori; Kato, Susumu; Fujiwara, Yutaka; Itagaki, Hirotomo; Kiyama, Satoru; Kim, Jaeho; Ikehara, Sanae; Shimizu, Nobuyuki; Nakanishi, Hayao; Ikehara, Yuzuru; Sakakita, Hajime

2018-05-01

In a low-temperature atmospheric pressure plasma jet using helium gas, emission-propagation phenomena, such as streamers and striations were measured using a high-speed intensified charge-coupled device camera. A particular focus was placed on the study of the dependence of the phenomena on the distance between the nozzle of the plasma device and a target plate. When the distance decreased, a transition from the positive streamer to a spatially continuous emission resulted. A further distance reduction resulted in a new propagation mode in which the positive and negative streamers appeared alternately with different current waveforms over two cycles of applied voltage. This phenomenon may be related to residual charges of the preceding cycle when streamer propagation begins. Striation structures were observed in the tail of the positive streamer head and in the successive spatially continuous-emission region. These structures can be measured only within a shorter period than one voltage cycle.

Efficacy of Monitoring Devices in Support of Prevention of Pressure Injuries: Systematic Review and Meta-analysis.

PubMed

Walia, Gurjot S; Wong, Alison L; Lo, Andrea Y; Mackert, Gina A; Carl, Hannah M; Pedreira, Rachel A; Bello, Ricardo; Aquino, Carla S; Padula, William V; Sacks, Justin M

2016-12-01

To present a systematic review of the literature assessing the efficacy of monitoring devices for reducing the risk of developing pressure injuries. This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care. After participating in this educational activity, the participant should be better able to:1. Explain the methodology of the literature review and its results.2. Discuss the scope of the problem and the implications of the research. OBJECTIVE: To assess the efficacy of monitoring devices for reducing the risk of developing pressure injuries (PIs). The authors systematically reviewed the literature by searching PubMed/MEDLINE and CINAHL databases through January 2016. Articles included clinical trials and cohort studies that tested monitoring devices, evaluating PI risk factors on patients in acute and skilled nursing settings. The articles were scored using the Methodological Index for Non-randomized Studies. Using a standardized extraction form, the authors extracted patient inclusion/exclusion criteria, care setting, key baseline, description of monitoring device and methodology, number of patients included in each group, description of any standard of care, follow-up period, and outcomes. Of the identified 1866 publications, 9 met the inclusion criteria. The high-quality studies averaged Methodological Index for Non-randomized Studies scores of 19.4 for clinical trials and 12.2 for observational studies. These studies evaluated monitoring devices that measured interface pressure, subdermal tissue stress, motion, and moisture. Most studies found a statistically significant decrease in PIs; 2 studies were eligible for meta-analysis, demonstrating that use of monitoring devices was associated with an 88% reduction in the risk of developing PIs (Mantel-Haenszel risk ratio, 0.12; 95% confidence interval, 0.04-0.41; I = 0%). Pressure injury monitoring devices are associated with a strong reduction in the risk of developing PIs. These devices provide clinicians and patients with critical information to implement prevention guidelines. Randomized controlled trials would help assess which technologies are most effective at reducing the risk of developing PIs.

Automatic dew-point temperature sensor.

PubMed

Graichen, H; Rascati, R; Gonzalez, R R

1982-06-01

A device is described for measuring dew-point temperature and water vapor pressure in small confined areas. The method is based on the deposition of water on a cooled surface when at dew-point temperature. A small Peltier module lowers the temperature of two electrically conductive plates. At dew point the insulating gap separating the plates becomes conductive as water vapor condenses. Sensors based on this principle can be made small and rugged and can be used for measuring directly the local water vapor pressure. They may be installed within a conventional ventilated sweat capsule used for measuring water vapor loss from the skin surface. A novel application is the measurement of the water vapor pressure gradients across layers of clothing worn by an exercising subject.

40 CFR 264.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2014 CFR

2014-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief devices in light liquid...

40 CFR 264.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2011 CFR

2011-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief devices in light liquid...

40 CFR 264.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2012 CFR

2012-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief devices in light liquid...

40 CFR 264.1058 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

Code of Federal Regulations, 2013 CFR

2013-07-01

... liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other... heavy liquid service, pressure relief devices in light liquid or heavy liquid service, and flanges and other connectors. (a) Pumps and valves in heavy liquid service, pressure relief devices in light liquid...

Corpuls cpr resuscitation device generates superior emulated flows and pressures than LUCAS II in a mechanical thorax model.

PubMed

Eichhorn, S; Mendoza Garcia, A; Polski, M; Spindler, J; Stroh, A; Heller, M; Lange, R; Krane, M

2017-06-01

The provision of sufficient chest compression is among the most important factors influencing patient survival during cardiopulmonary resuscitation (CPR). One approach to optimize the quality of chest compressions is to use mechanical-resuscitation devices. The aim of this study was to compare a new device for chest compression (corpuls cpr) with an established device (LUCAS II). We used a mechanical thorax model consisting of a chest with variable stiffness and an integrated heart chamber which generated blood flow dependent on the compression depth and waveform. The method of blood-flow generation could be changed between direct cardiac-compression mode and thoracic-pump mode. Different chest-stiffness settings and compression modes were tested to generate various blood-flow profiles. Additionally, an endurance test at high stiffness was performed to measure overall performance and compression consistency. Both resuscitation machines were able to compress the model thorax with a frequency of 100/min and a depth of 5 cm, independent of the chosen chest stiffness. Both devices passed the endurance test without difficulty. The corpuls cpr device was able to generate about 10-40% more blood flow than the LUCAS II device, depending on the model settings. In most scenarios, the corpuls cpr device also generated a higher blood pressure than the LUCAS II. The peak compression forces during CPR were about 30% higher using the corpuls cpr device than with the LUCAS II. In this study, the corpuls cpr device had improved blood flow and pressure outcomes than the LUCAS II device. Further examination in an animal model is required to prove the findings of this preliminary study.

RIGHT VENTRICULAR UNLOADING AND RESPIRATORY SUPPORT WITH A WEARABLE ARTIFICIAL PUMP-LUNG (APL) IN AN OVINE MODEL

PubMed Central

Liu, Yang; Sanchez, Pablo G; Wei, Xufeng; Li, Tieluo; Watkins, Amelia C; Li, Shu-ying; Griffith, Bartley P; Wu, Zhongjun J

2014-01-01

Background Device availability of mechanical circulatory or respiratory support to the right heart has been limited. The purpose of this study was to investigate the effect of right heart unloading and respiratory support with a wearable integrated artificial pump-lung (APL). Methods The APL device was placed surgically between the right atrium and pulmonary artery in seven sheep. Anticoagulation was performed with heparin infusion. Its ability to unload the right ventricle (RV) was investigated by echocardiograms and right heart catheterization at different bypass flow rates. Hemodynamics and Echo data were evaluated. The device flow and gas transfer rates were also measured at different device speeds. Results Hemodynamics remained stable during APL support. There was no significant change in systemic blood pressure and cardiac index. Central venous pressure, RV pressure, RV end-diastolic dimension and RV ejection fraction were significant decreased when APL device flow rate approached 2 L/min. The linear regression showed significant correlative trends between the hemodynamic and cardiac indices and the device speed. The oxygen transfer rate increased with the device speed. The oxygen saturation from APL outlet was fully saturated (>95%) during the support. The impact of the APL support on blood elements (plasma free hemoglobin and platelet activation) was minimal. Conclusion The APL device support significantly unloaded the right ventricle with increasing device speed. The APL device provided stable hemodynamic and respiratory support in terms of blood flow and oxygen transfer. The right heart unloading performance of this wearable device need to be evaluated in the animal model with right heart failure for a long term support. PMID:24746636

Differential-optoacoustic absorption detector

NASA Technical Reports Server (NTRS)

Shumate, M. S.

1977-01-01

Two-cell spectrophone detects trace amounts of atmospheric pollutants by measuring absorption coefficients of gases with various laser sources. Device measures pressure difference between two tapered cells with differential manometer. Background signal is reduced by balanced window heating and balanced carrier gas absorption in two cells.

Challenges in automated estimation of capillary refill time in dogs

NASA Astrophysics Data System (ADS)

Cugmas, Blaž; Spigulis, Janis

2018-02-01

Capillary refill time (CRT) is a part of the cardiorespiratory examination in dogs. Changes in CRT can reflect pathological conditions like shock or anemia. Visual CRT estimation has low repeatability; therefore, optical systems for automated estimation have recently appeared. Since existing systems are unsuitable for use in dogs, we designed a simple, small and portable device, which could be easily used at veterinary clinic. The device was preliminarily tested on several measurement sites in two dogs. Not all measurement sites were suitable for CRT measurements due to underlying tissue optical and mechanical properties. The CRT measurements were possible on the labial mucosa, above the sternum and on the digit where CRT was in the range of values, retrieved from the color video of the visual CRT measurement. It seems that light penetration predominantly governs tissue optical response when the pressure is applied. Therefore, it is important to select a proper light, which reaches only superficial capillaries and does not penetrate deeper. Blue or green light is probably suitable for light skin or mucosa, on the other hand, red or near-infrared might be used for skin with pigmented or thick epidermis. Additionally, further improvements of the device design are considered, like adding a calibrated spring, which would insure application of consistent pressure.

Toward Development of a Field-Deployable Imaging Device for TBI

DTIC Science & Technology

2015-06-01

proportional to the Young modulus with the following relationship: E = 3ρc2, where E is the Young modulus (kilopascals), a measure of the resistance of...Fang M, Jiang WQ, Zhu GF, Zeng HK. Effect of hydroxyethyl starch on intracranial pressure and plasma colloid osmotic pressure in rats with cerebral...creates images of Young’s Modulus, a measure of 81 the resistance to such that larger values describe stiffer tissue. Therefore, maps of Young’s 82

Blood pressure measurement in obese patients: comparison between upper arm and forearm measurements.

PubMed

Pierin, Angela M G; Alavarce, Débora C; Gusmão, Josiane L; Halpern, Alfredo; Mion, Décio

2004-06-01

It is well known that blood pressure measurement with a standard 12-13 cm wide cuff is erroneous for large arms. To compare arm blood pressure measurements with an appropriate cuff and forearm blood pressure measurements (BPM) with a standard cuff, and both measurements by the Photopletismography (Finapres) method. One hundred and twenty-nine obese patients were studied (body mass index=40+/-7 kg/m2). The patients had three arm BPM taken by an automatic oscillometric device using an appropriate cuff and three forearm BPM with a standard cuff in the sitting position after a five-minute rest. Data were analysed by the analysis of variance. The correction values were obtained by the linear regression test. Systolic and diastolic arm BPM with an appropriate cuff were significantly lower (p<0.05) than forearm BPM with a standard cuff. The measurements obtained by Finapres were significantly lower (p<0.05) than those found for forearm systolic and diastolic blood pressures and upper arm diastolic blood pressure. The equation to correct BPM in forearm in obese patients with arm circumference between 32-44 cm was: systolic BPM=33.2+/-0.68 x systolic forearm BPM, and diastolic BPM=25.2+0.59 x forearm diastolic BPM. This study showed that forearm blood pressure measurement overestimates the values of arm blood pressure measurement. In addition, it is possible to correct forearm BPM with an equation.

Pressure in isochoric systems containing aqueous solutions at subzero Centigrade temperatures

PubMed Central

Șerban, Alexandru; Rubinsky, Boris

2017-01-01

Objective Preservation of biological materials at subzero Centigrade temperatures, cryopreservation, is important for the field of tissue engineering and organ transplantation. Our group is studying the use of isochoric (constant volume) systems of aqueous solution for cryopreservation. Previous studies measured the pressure-temperature relations in aqueous isochoric systems in the temperature range from 0°C to – 20°C. The goal of this study is to expand the pressure-temperature measurement beyond the range reported in previous publications. Materials and methods To expand the pressure-temperature measurements beyond the previous range, we have developed a new isochoric device capable of withstanding liquid nitrogen temperatures and pressures of up to 413 MPa. The device is instrumented with a pressure transducer than can monitor and record the pressures in the isochoric chamber in real time. Measurements were made in a temperature range from – 5°C to liquid nitrogen temperatures for various solutions of pure water and Me2SO (a chemical additive used for protection of biological materials in a frozen state and for vitrification (glass formation) of biological matter). Undissolved gaseous are is carefully removed from the system. Results Temperature-pressure data from – 5°C to liquid nitrogen temperature for pure water and other solutions are presented in this study. Following are examples of some, temperature-pressure values, that were measured in an isochoric system containing pure water: (- 20°C, 187 MPa); (-25°C, 216 MPa); (- 30°C, 242.3 MPa); (-180°C, 124 MPa). The data is consistent with the literature, which reports that the pressure and temperature at the triple point, between ice I, ice III and water is, - 21.993°C and 209.9 MPa, respectively. It was surprising to find that the pressure in the isochoric system increases at temperatures below the triple point and remains high to liquid nitrogen temperatures. Measurements of pressure-temperature relations in solutions of pure water and Me2SO in different concentrations show that, for concentrations in which vitrification is predicted, no increase in pressure was measured during rapid cooling to liquid nitrogen temperatures. However, ice formation either during cooling or warming to and from liquid nitrogen temperatures produced an increase in pressure. Conclusions The data obtained in this study can be used to aid in the design of isochoric cryopreservation protocols. The results suggest that the pressure measurement is important in the design of “constant volume” systems and can provide a simple means to gain information on the occurrence of vitrification and devitrification during cryopreservation processes of aqueous solutions in an isochoric system. PMID:28817681

Pressure balanced drag turbine mass flow meter

DOEpatents

Dacus, M.W.; Cole, J.H.

1980-04-23

The density of the fluid flowing through a tubular member may be measured by a device comprising a rotor assembly suspended within the tubular member, a fluid bearing medium for the rotor assembly shaft, independent fluid flow lines to each bearing chamber, and a scheme for detection of any difference between the upstream and downstream bearing fluid pressures. The rotor assembly reacts to fluid flow both by rotation and axial displacement; therefore concurrent measurements may be made of the velocity of blade rotation and also bearing pressure changes, where the pressure changes may be equated to the fluid momentum flux imparted to the rotor blades. From these parameters the flow velocity and density of the fluid may be deduced.

Pressure balanced drag turbine mass flow meter

DOEpatents

Dacus, Michael W.; Cole, Jack H.

1982-01-01

The density of the fluid flowing through a tubular member may be measured by a device comprising a rotor assembly suspended within the tubular member, a fluid bearing medium for the rotor assembly shaft, independent fluid flow lines to each bearing chamber, and a scheme for detection of any difference between the upstream and downstream bearing fluid pressures. The rotor assembly reacts to fluid flow both by rotation and axial displacement; therefore concurrent measurements may be made of the velocity of blade rotation and also bearing pressure changes, where the pressure changes may be equated to the fluid momentum flux imparted to the rotor blades. From these parameters the flow velocity and density of the fluid may be deduced.

Design and development of a novel strain gauge automatic pasting device for mini split Hopkinson pressure bar

NASA Astrophysics Data System (ADS)

Huang, Wenkai; Huan, Shi; He, Junfeng; Jiang, Jichang

2018-03-01

In a split Hopkinson pressure bar (SHPB) experiment, the pasting quality of strain gauges will directly affect the accuracy of the measurement results. The traditional method of pasting the strain gauges is done manually by the experimenter. In the process of pasting, it is easy to shift or twist the strain gauge, and the experimental results are greatly affected by human factors. In this paper, a novel type automatic pasting device for strain gauges is designed and developed, which can be used to accurately and rapidly paste the strain gauges. The paste quality is reliable, and it can guarantee the consistency of SHPB experimental measurement. We found that a clamping force of 74 N achieved a success rate of 97%, whilst ensuring good adhesion.

Passive tire pressure sensor and method

DOEpatents

Pfeifer, Kent Bryant; Williams, Robert Leslie; Waldschmidt, Robert Lee; Morgan, Catherine Hook

2006-08-29

A surface acoustic wave device includes a micro-machined pressure transducer for monitoring tire pressure. The device is configured having a micro-machined cavity that is sealed with a flexible conductive membrane. When an external tire pressure equivalent to the cavity pressure is detected, the membrane makes contact with ridges on the backside of the surface acoustic wave device. The ridges are electrically connected to conductive fingers of the device. When the detected pressure is correct, selected fingers on the device will be grounded producing patterned acoustic reflections to an impulse RF signal. When the external tire pressure is less than the cavity reference pressure, a reduced reflected signal to the receiver results. The sensor may further be constructed so as to identify itself by a unique reflected identification pulse series.

Passive tire pressure sensor and method

DOEpatents

Pfeifer, Kent Bryant; Williams, Robert Leslie; Waldschmidt, Robert Lee; Morgan, Catherine Hook

2007-09-04

A surface acoustic wave device includes a micro-machined pressure transducer for monitoring tire pressure. The device is configured having a micro-machined cavity that is sealed with a flexible conductive membrane. When an external tire pressure equivalent to the cavity pressure is detected, the membrane makes contact with ridges on the backside of the surface acoustic wave device. The ridges are electrically connected to conductive fingers of the device. When the detected pressure is correct, selected fingers on the device will be grounded producing patterned acoustic reflections to an impulse RF signal. When the external tire pressure is less than the cavity reference pressure, a reduced reflected signal to the receiver results. The sensor may further be constructed so as to identify itself by a unique reflected identification pulse series.

Screening the Hanford tanks for trapped gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whitney, P.

1995-10-01

The Hanford Site is home to 177 large, underground nuclear waste storage tanks. Hydrogen gas is generated within the waste in these tanks. This document presents the results of a screening of Hanford`s nuclear waste storage tanks for the presence of gas trapped in the waste. The method used for the screening is to look for an inverse correlation between waste level measurements and ambient atmospheric pressure. If the waste level in a tank decreases with an increase in ambient atmospheric pressure, then the compressibility may be attributed to gas trapped within the waste. In this report, this methodology ismore » not used to estimate the volume of gas trapped in the waste. The waste level measurements used in this study were made primarily to monitor the tanks for leaks and intrusions. Four measurement devices are widely used in these tanks. Three of these measure the level of the waste surface. The remaining device measures from within a well embedded in the waste, thereby monitoring the liquid level even if the liquid level is below a dry waste crust. In the past, a steady rise in waste level has been taken as an indicator of trapped gas. This indicator is not part of the screening calculation described in this report; however, a possible explanation for the rise is given by the mathematical relation between atmospheric pressure and waste level used to support the screening calculation. The screening was applied to data from each measurement device in each tank. If any of these data for a single tank indicated trapped gas, that tank was flagged by this screening process. A total of 58 of the 177 Hanford tanks were flagged as containing trapped gas, including 21 of the 25 tanks currently on the flammable gas watch list.« less

Comparison of the characteristics of small commercial NDIR CO2 sensor models and development of a portable CO2 measurement device.

PubMed

Yasuda, Tomomi; Yonemura, Seiichiro; Tani, Akira

2012-01-01

Many sensors have to be used simultaneously for multipoint carbon dioxide (CO(2)) observation. All the sensors should be calibrated in advance, but this is a time-consuming process. To seek a simplified calibration method, we used four commercial CO(2) sensor models and characterized their output tendencies against ambient temperature and length of use, in addition to offset characteristics. We used four samples of standard gas with different CO(2) concentrations (0, 407, 1,110, and 1,810 ppm). The outputs of K30 and AN100 models showed linear relationships with temperature and length of use. Calibration coefficients for sensor models were determined using the data from three individual sensors of the same model to minimize the relative RMS error. When the correction was applied to the sensors, the accuracy of measurements improved significantly in the case of the K30 and AN100 units. In particular, in the case of K30 the relative RMS error decreased from 24% to 4%. Hence, we have chosen K30 for developing a portable CO(2) measurement device (10 × 10 × 15 cm, 900 g). Data of CO(2) concentration, measurement time and location, temperature, humidity, and atmospheric pressure can be recorded onto a Secure Digital (SD) memory card. The CO(2) concentration in a high-school lecture room was monitored with this device. The CO(2) data, when corrected for simultaneously measured temperature, water vapor partial pressure, and atmospheric pressure, showed a good agreement with the data measured by a highly accurate CO(2) analyzer, LI-6262. This indicates that acceptable accuracy can be realized using the calibration method developed in this study.

Comparison of the Characteristics of Small Commercial NDIR CO2 Sensor Models and Development of a Portable CO2 Measurement Device

PubMed Central

Yasuda, Tomomi; Yonemura, Seiichiro; Tani, Akira

2012-01-01

Many sensors have to be used simultaneously for multipoint carbon dioxide (CO2) observation. All the sensors should be calibrated in advance, but this is a time-consuming process. To seek a simplified calibration method, we used four commercial CO2 sensor models and characterized their output tendencies against ambient temperature and length of use, in addition to offset characteristics. We used four samples of standard gas with different CO2 concentrations (0, 407, 1,110, and 1,810 ppm). The outputs of K30 and AN100 models showed linear relationships with temperature and length of use. Calibration coefficients for sensor models were determined using the data from three individual sensors of the same model to minimize the relative RMS error. When the correction was applied to the sensors, the accuracy of measurements improved significantly in the case of the K30 and AN100 units. In particular, in the case of K30 the relative RMS error decreased from 24% to 4%. Hence, we have chosen K30 for developing a portable CO2 measurement device (10 × 10 × 15 cm, 900 g). Data of CO2 concentration, measurement time and location, temperature, humidity, and atmospheric pressure can be recorded onto a Secure Digital (SD) memory card. The CO2 concentration in a high-school lecture room was monitored with this device. The CO2 data, when corrected for simultaneously measured temperature, water vapor partial pressure, and atmospheric pressure, showed a good agreement with the data measured by a highly accurate CO2 analyzer, LI-6262. This indicates that acceptable accuracy can be realized using the calibration method developed in this study. PMID:22737029

21 CFR 878.4683 - Non-Powered suction apparatus device intended for negative pressure wound therapy.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Non-Powered suction apparatus device intended for... Surgical Devices § 878.4683 Non-Powered suction apparatus device intended for negative pressure wound therapy. (a) Identification. A non-powered suction apparatus device intended for negative pressure wound...

A pressure core ultrasonic test system for on-board analysis of gas hydrate-bearing sediments under in situ pressures.

PubMed

Yang, Lei; Zhou, Weihua; Xue, Kaihua; Wei, Rupeng; Ling, Zheng

2018-05-01

The enormous potential as an alternative energy resource has made natural gas hydrates a material of intense research interest. Their exploration and sample characterization require a quick and effective analysis of the hydrate-bearing cores recovered under in situ pressures. Here a novel Pressure Core Ultrasonic Test System (PCUTS) for on-board analysis of sediment cores containing gas hydrates at in situ pressures is presented. The PCUTS is designed to be compatible with an on-board pressure core transfer device and a long gravity-piston pressure-retained corer. It provides several advantages over laboratory core analysis including quick and non-destructive detection, in situ and successive acoustic property acquisition, and remission of sample storage and transportation. The design of the unique assembly units to ensure the in situ detection is demonstrated, involving the U-type protecting jackets, transducer precession device, and pressure stabilization system. The in situ P-wave velocity measurements make the detection of gas hydrate existence in the sediments possible on-board. Performance tests have verified the feasibility and sensitivity of the ultrasonic test unit, showing the dependence of P-wave velocity on gas hydrate saturation. The PCUTS has been successfully applied for analysis of natural samples containing gas hydrates recovered from the South China Sea. It is indicated that on-board P-wave measurements could provide a quick and effective understanding of the hydrate occurrence in natural samples, which can assist further resource exploration, assessment, and subsequent detailed core analysis.

A pressure core ultrasonic test system for on-board analysis of gas hydrate-bearing sediments under in situ pressures

NASA Astrophysics Data System (ADS)

Yang, Lei; Zhou, Weihua; Xue, Kaihua; Wei, Rupeng; Ling, Zheng

2018-05-01

The enormous potential as an alternative energy resource has made natural gas hydrates a material of intense research interest. Their exploration and sample characterization require a quick and effective analysis of the hydrate-bearing cores recovered under in situ pressures. Here a novel Pressure Core Ultrasonic Test System (PCUTS) for on-board analysis of sediment cores containing gas hydrates at in situ pressures is presented. The PCUTS is designed to be compatible with an on-board pressure core transfer device and a long gravity-piston pressure-retained corer. It provides several advantages over laboratory core analysis including quick and non-destructive detection, in situ and successive acoustic property acquisition, and remission of sample storage and transportation. The design of the unique assembly units to ensure the in situ detection is demonstrated, involving the U-type protecting jackets, transducer precession device, and pressure stabilization system. The in situ P-wave velocity measurements make the detection of gas hydrate existence in the sediments possible on-board. Performance tests have verified the feasibility and sensitivity of the ultrasonic test unit, showing the dependence of P-wave velocity on gas hydrate saturation. The PCUTS has been successfully applied for analysis of natural samples containing gas hydrates recovered from the South China Sea. It is indicated that on-board P-wave measurements could provide a quick and effective understanding of the hydrate occurrence in natural samples, which can assist further resource exploration, assessment, and subsequent detailed core analysis.

Short term evaluation of respiratory effort by premature infants supported with bubble nasal continuous airway pressure using Seattle-PAP and a standard bubble device

PubMed Central

Welty, Stephen E.; Rusin, Craig G.; Stanberry, Larissa I.; Mandy, George T.; Gest, Alfred L.; Ford, Jeremy M.; Backes, Carl H.; Richardson, C. Peter; Howard, Christopher R.; Hansen, Thomas N.

2018-01-01

Background Almost one million prematurely born infants die annually from respiratory insufficiency, predominantly in countries with limited access to respiratory support for neonates. The primary hypothesis tested in the present study was that a modified device for bubble nasal continuous positive airway pressure (Bn-CPAP) would provide lower work of spontaneous breathing, estimated by esophageal pressure-rate products. Methods Infants born <32 weeks gestation and stable on Bn-CPAP with FiO2 <0.30 were studied within 72 h following delivery. Esophageal pressures during spontaneous breathing were measured during 2 h on standard Bn-CPAP, then 2 h with Bn-CPAP using a modified bubble device presently termed Seattle-PAP, which produces a different pattern of pressure fluctuations and which provided greater respiratory support in preclinical studies, then 2 h on standard Bn-CPAP. Results All 40 infants enrolled completed the study and follow-up through 36 wks post menstrual age or hospital discharge, whichever came first. No infants were on supplemental oxygen at completion of follow-up. No infants developed pneumothoraces or nasal trauma, and no adverse events attributed to the study were observed. Pressure-rate products on the two devices were not different, but effort of breathing, assessed by areas under esophageal pressure-time curves, was lower with Seattle-PAP than with standard Bn-CPAP. Conclusion Use of Seattle-PAP to implement Bn-CPAP lowers the effort of breathing exerted even by relatively healthy spontaneously breathing premature neonates. Whether the lower effort of breathing observed with Seattle-PAP translates to improvements in neonatal mortality or morbidity will need to be determined by studies in appropriate patient populations. PMID:29590143

Comparison of noninvasive blood pressure measurement techniques via the coccygeal artery in anesthetized cheetahs (Acinonyx jubatus).

PubMed

Sadler, Ryan A; Hall, Natalie H; Kass, Philip H; Citino, Scott B

2013-12-01

Two indirect blood pressure measurement techniques, Doppler (DOP) sphygmomanometry and oscillometry, applied at the ventral coccygeal artery were compared with simultaneous direct blood pressure measurements at the dorsal pedal artery in 10 anesthetized, captive cheetahs (Acinonyx jubatus). The DOP method was moderately accurate, with relatively little bias (mean difference 3.8 mmHg) and 88.6% of the DOP systolic arterial pressure measurements being within 10 mmHg of the direct systolic arterial measurement. With the oscillometric (OM) method, 89.2% of the mean arterial pressure measurements were within 10 mmHg of the direct measurement and had the least bias (mean difference 2.3 mmHg), 80.7% of the systolic measurements were within 10 mmHg of the direct measurement and had the second least bias (mean difference 2.3 mmHg), and 59% of the diastolic measurements were within 10 mmHg of the direct measurement and had significant bias (mean difference 7.3 mmHg). However, DOP showed relatively poor precision (SD 11.2 mmHg) compared with OM systolic (SD 8.0 mmHg), diastolic (SD 8.6 mmHg), and mean (SD 5.7 mmHg). Both techniques showed a linear relationship with the direct technique measurements over a wide range of blood pressures. The DOP method tended to underestimate systolic measurements below 160 mmHg and overestimate systolic measurements above 160 mmHg. The OM method tended to underestimate mean pressures below 160 mm Hg, overestimate mean pressures above 160 mmHg, underestimate systolic pressures below 170 mmHg, overestimate systolic pressures above 170 mmHg, and underestimate diastolic pressures throughout the measured blood pressure range. Indirect blood pressure measurement using the ventral coccygeal artery, particularly when using an OM device for mean and systolic arterial pressure, may be useful in the clinical assessment of cheetahs when monitoring trends over time, but caution should be taken when interpreting individual values.

Gasometer: An inexpensive device for continuous monitoring of dissolved gases and supersaturation

USGS Publications Warehouse

Bouck, G.R.

1982-01-01

The “gasometer” is a device that measures differential dissolved-gas pressures (δP) in water relative to barometric pressure (as does the “Weiss saturometer”), but operates continuously without human attention. The gasometer can be plumbed into a water-supply system and requires 8 liters/minute of water or more at 60 kilopascals. The gasometer's surfaces are nontoxic, and flow-through water can be used for fish culture. The gasometer may be connected to a small submersible pump and operated as a portable unit. The gasometer can activate an alarm system and thus protect fish from hyperbaric (supersaturation) or hypobaric gas pressures (usually due to low dissolved oxygen). Instructions are included for calculating and reporting data including the pressure and saturation of individual gases. Construction and performance standards are given for the gasometer. Occasional cleaning is required to remove biofouling from the gas-permeable tubing.PDF