Imaging diagnosis--Use of multiphasic contrast-enhanced computed tomography for diagnosis of mesenteric volvulus in a dog.

PubMed

Chow, Kathleen Ella; Stent, Andrew William; Milne, Marjorie

2014-01-01

A 4-year-old German shorthaired pointer presented with collapse and hematochezia. Radiographs showed gas and fluid-distended small intestines and loss of serosal detail. Ultrasound examination showed hypomotile, fluid-distended small intestines, and thrombosed jejunal veins. Multiphasic contrast-enhanced computed tomography was performed and showed a CT "whirl sign," an important but nonspecific sign of intestinal volvulus in human patients. At surgery, the majority of the small intestine was entangled in the volvulus and showed black discoloration. The patient was euthanized. Postmortem evaluation yielded a diagnosis of jejunoileal mesenteric volvulus secondary to a congenital omphalomesenteric duct remnant. © 2013 American College of Veterinary Radiology.

Heart bypass surgery

MedlinePlus

Off-pump coronary artery bypass; OPCAB; Beating heart surgery; Bypass surgery - heart; CABG; Coronary artery bypass graft; Coronary artery bypass surgery; Coronary bypass surgery; Coronary artery disease - CABG; CAD - CABG; Angina - ...

Bypass apparatus and method for series connected energy storage devices

DOEpatents

Rouillard, Jean; Comte, Christophe; Daigle, Dominik

2000-01-01

A bypass apparatus and method for series connected energy storage devices. Each of the energy storage devices coupled to a common series connection has an associated bypass unit connected thereto in parallel. A current bypass unit includes a sensor which is coupled in parallel with an associated energy storage device or cell and senses an energy parameter indicative of an energy state of the cell, such as cell voltage. A bypass switch is coupled in parallel with the energy storage cell and operable between a non-activated state and an activated state. The bypass switch, when in the non-activated state, is substantially non-conductive with respect to current passing through the energy storage cell and, when in the activated state, provides a bypass current path for passing current to the series connection so as to bypass the associated cell. A controller controls activation of the bypass switch in response to the voltage of the cell deviating from a pre-established voltage setpoint. The controller may be included within the bypass unit or be disposed on a control platform external to the bypass unit. The bypass switch may, when activated, establish a permanent or a temporary bypass current path.

Gastric bypass surgery - discharge

MedlinePlus

... bypass - discharge; Gastric bypass - Roux-en-Y - discharge; Obesity gastric bypass discharge; Weight loss - gastric bypass discharge ... al. Bariatric surgery versus non-surgical treatment for obesity: a systematic review and meta-analysis of randomised ...

Occipital-posterior cerebral artery bypass via the occipital interhemispheric approach

PubMed Central

Kazumata, Ken; Yokoyama, Yuka; Sugiyama, Taku; Asaoka, Katsuyuki

2013-01-01

Background: The unavailability of the superficial temporal artery (STA) and the location of lesions pose a more technically demanding challenge when compared with conventional STA-superior cerebellar or posterior cerebral artery (PCA) bypass in vascular reconstruction procedures. To describe a case series of patients with cerebrovascular lesions who were treated using an occipital artery (OA) to PCA bypass via the occipital interhemispheric approach. Methods: We retrospectively reviewed three consecutive cases of patients with cerebrovascular lesions who were treated using OA-PCA bypass. Results: OA-PCA bypass was performed via the occipital interhemispheric approach. This procedure included: (1) OA-PCA bypass (n = 1), and combined OA-posterior inferior cerebellar artery and OA-PCA saphenous vein interposition graft bypass (n = 1) in patients with vertebrobasilar ischemia; (2) OA-PCA radial artery interposition graft bypass in one patient with residual PCA aneurysm. Conclusions: OA-PCA bypass represents a useful alternative to conventional STA-SCA or PCA bypass. PMID:23956933

Simple training tricks for mastering and taming bypass procedures in neurosurgery

PubMed Central

Hafez, Ahmad; Raj, Rahul; Lawton, Michael T.; Niemelä, Mika

2017-01-01

Background: Neurosurgeons devoted to bypass neurosurgery or revascularization neurosurgery are becoming scarcer. From a practical point of view, “bypass neurosurgeons” are anastomosis makers, vessels technicians, and time-racing repairers of vessel walls. This requires understanding the key features and hidden tricks of bypass surgery. The goal of this paper is to provide simple and inexpensive tricks for taming the art of bypass neurosurgery. Most of these tricks and materials described can be borrowed, donated, or purchased inexpensively. Methods: We performed a review of relevant training materials and recorded videos for training bypass procedures for 3 years between June 2014 and July 2017. In total, 1,300 training bypass procedures were performed, of which 200 procedures were chosen for this paper. Results: A training laboratory bypass procedures is required to enable a neurosurgeon to develop the necessary skills. The important skills for training bypass procedures gained through meticulous practice to be as reflexes are coordination, speed, agility, flexibility, and reaction time. Bypassing requires synchronization between the surgeon's gross movements, fine motoric skills, and mental strength. The suturing rhythm must be timed in a brain–body–hand fashion. Conclusion: Bypass-training is a critical part of neurosurgical training and not for a selected few. Diligent and meticulous training can enable every neurosurgeon to tame the art of bypass neurosurgery. This requires understanding the key features and hidden tricks of bypass surgery, as well as uncountable hours of training. In bypass neurosurgery, quality and time goes hand in hand. PMID:29285411

Passage of downstream migrant American eels through an airlift-assisted deep bypass

USGS Publications Warehouse

Haro, Alexander J.; Watten, Barnaby J.; Noreika, John

2016-01-01

Traditional downstream guidance and bypass facilities for anadromous fishes (i.e., surface bypasses, surface guidance structures, and behavioral barriers) have frequently been ineffective for anguillid eels. Because eels typically spend the majority of their time near the bottom in the vicinity of intake structures, deep bypass structures with entrances near the bottom hold promise for increased effectiveness, thereby aiding in the recovery of this important species. A new design of a deep bypass system that uses airlift technology (the Conte Airlift Bypass) to induce flow in a bypass pipe was tested in a simulated intake entrance environment under controlled laboratory conditions. Water velocities of 0.9–1.5 m s−1 could be generated at the bypass entrance (opening with 0.073 m2 area), with corresponding flows through the bypass pipe of 0.07–0.11 m3 s−1. Gas saturation and hydrostatic pressure within the bypass pipe did not vary appreciably from a control (no air) condition under tested airflows. Migratory silver-phase American eels (Anguilla rostrata) tested during dark conditions readily located, entered, and passed through the bypass; initial avoidance rates (eels approaching but not entering the bypass entrance) were lower at higher entrance velocities. Eels that investigated the bypass pipe entrance tended to enter headfirst, but those that then exited the pipe upstream did so more frequently at lower entrance velocities. Eels appeared to swim against the flow while being transported downstream through the pipe; median transit times through the bypass for each test velocity ranged from 5.8 to 12.2 s, with transit time decreasing with increasing entrance velocity. Eels did not show strong avoidance of the vertical section of the pipe which contained injected air. No mortality or injury of bypassed eels was observed, and individual eels repeatedly passed through the bypass at rates of up to 40 passes per hour, suggesting that individuals do not avoid repeated entrainment through the bypass. Airlift technology appears to be a viable method for increasing passage effectiveness for American eels through a deep bypass system.

Postoperative enlargement and prognostic effects of portal venous bypass grafts in children undergoing Rex shunt.

PubMed

Zhang, Jin-Shan; Li, Long; Cheng, Wei

2018-05-22

Patency of the bypass vein after a Rex shunt is an important indicator of prognosis. However, there is no report about the change of caliber of the bypass vein after a Rex shunt. The aim of this study was to identify postoperative changes of the bypass vein and to assess the relationship with prognosis. Between October 2008 and October 2016 in our center, 114 children were diagnosed with extrahepatic portal venous obstruction. The portal cavernoma-portal bypass with interposition of grafted portal vessels was performed in 31 children, the gastroportal shunt was performed in 54 children, and other Rex shunts were performed in another 29 children. At follow-up, the patency and diameter of the bypass vein were assessed with ultrasound and computed tomography. The intraoperative and postoperative diameters of the bypass vein were compared to identify postoperative changes of the bypass vein. Prognosis was compared between children with and children without an enlarged bypass vein. The caliber of the bypass vein was enlarged in 50% of children (40/80) at 6 months postoperatively. The postoperative incidences of rebleeding and esophageal varices were significantly lower in children with an enlarged bypass vein than in those without (P < .05). Postoperatively, the reduced splenic size was significantly higher in children with an enlarged bypass vein than in those without (P < .05). The postoperative increase in platelet count in children with an enlarged bypass vein was significantly higher than in those without (P = .006). There was no significant difference in the flow velocity of the bypass vein between children with and children without an enlarged bypass vein (P = .133). The portal pressure was significantly reduced after surgery in children with an enlarged bypass vein than in children without an enlarged bypass vein (P = .017). The caliber of the bypass vein increases in 50% of children after a Rex shunt using a grafted portal vessel, which is related to a better prognosis. Copyright © 2018 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

21 CFR 870.4420 - Cardiopulmonary bypass cardiotomy return sucker.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass cardiotomy return sucker... Cardiopulmonary bypass cardiotomy return sucker. (a) Identification. A cardiopulmonary bypass cardiotomy return... from the chest or heart during cardiopulmonary bypass surgery. (b) Classification. Class II...

21 CFR 870.4420 - Cardiopulmonary bypass cardiotomy return sucker.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass cardiotomy return sucker... Cardiopulmonary bypass cardiotomy return sucker. (a) Identification. A cardiopulmonary bypass cardiotomy return... from the chest or heart during cardiopulmonary bypass surgery. (b) Classification. Class II...

21 CFR 870.4390 - Cardiopulmonary bypass pump tubing.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pump tubing. 870.4390... bypass pump tubing. (a) Identification. A cardiopulmonary bypass pump tubing is polymeric tubing which is... through the cardiopulmonary bypass circuit. (b) Classification. Class II (performance standards). ...

21 CFR 870.4320 - Cardiopulmonary bypass pulsatile flow generator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pulsatile flow generator... Cardiopulmonary bypass pulsatile flow generator. (a) Identification. A cardiopulmonary bypass pulsatile flow... device is placed in a cardiopulmonary bypass circuit downstream from the oxygenator. (b) Classification...

21 CFR 870.4390 - Cardiopulmonary bypass pump tubing.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass pump tubing. 870.4390... bypass pump tubing. (a) Identification. A cardiopulmonary bypass pump tubing is polymeric tubing which is... through the cardiopulmonary bypass circuit. (b) Classification. Class II (performance standards). ...

21 CFR 870.4320 - Cardiopulmonary bypass pulsatile flow generator.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass pulsatile flow generator... Cardiopulmonary bypass pulsatile flow generator. (a) Identification. A cardiopulmonary bypass pulsatile flow... device is placed in a cardiopulmonary bypass circuit downstream from the oxygenator. (b) Classification...

21 CFR 870.4350 - Cardiopulmonary bypass oxygenator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass oxygenator. 870.4350... bypass oxygenator. (a) Identification. A cardiopulmonary bypass oxygenator is a device used to exchange... the FDA guidance document entitled “Guidance for Cardiopulmonary Bypass Oxygenators 510(k) Submissions...

21 CFR 870.4350 - Cardiopulmonary bypass oxygenator.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass oxygenator. 870.4350... bypass oxygenator. (a) Identification. A cardiopulmonary bypass oxygenator is a device used to exchange... the FDA guidance document entitled “Guidance for Cardiopulmonary Bypass Oxygenators 510(k) Submissions...

21 CFR 870.4230 - Cardiopulmonary bypass defoamer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass defoamer. 870.4230 Section... bypass defoamer. (a) Identification. A cardiopulmonary bypass defoamer is a device used in conjunction with an oxygenator during cardiopulmonary bypass surgery to remove gas bubbles from the blood. (b...

21 CFR 870.4230 - Cardiopulmonary bypass defoamer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass defoamer. 870.4230 Section... bypass defoamer. (a) Identification. A cardiopulmonary bypass defoamer is a device used in conjunction with an oxygenator during cardiopulmonary bypass surgery to remove gas bubbles from the blood. (b...

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...

21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in conjunction with short-term extracorporeal circulation devices to hold a reserve supply of blood in the bypass...

21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in conjunction with short-term extracorporeal circulation devices to hold a reserve supply of blood in the bypass...

21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in conjunction with short-term extracorporeal circulation devices to hold a reserve supply of blood in the bypass...

21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in conjunction with short-term extracorporeal circulation devices to hold a reserve supply of blood in the bypass...

21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in conjunction with short-term extracorporeal circulation devices to hold a reserve supply of blood in the bypass...

21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class II...

21 CFR 870.4380 - Cardiopulmonary bypass pump speed control.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class II...

Bypass Surgery after Endovascular Therapy for Infrapopliteal Lesion Is Not a Poor Outcome Compared with Initial Bypass Surgery by Vascular Surgeons.

PubMed

Morisaki, Koichi; Yamaoka, Terutoshi; Iwasa, Kazuomi; Ohmine, Takahiro

2017-11-01

It is unclear whether prior endovascular therapy (EVT) adversely affects bypass surgery. The aim of this study is to investigate treatment outcomes between initial bypass (bypass-first) and bypass surgery after EVT (EVT-first). We conducted a retrospective analysis of critical limb ischemia patients undergoing infrapopliteal bypass between November 2006 and December 2015. Graft patency, limb salvage (LS), amputation-free survival (AFS), and overall survival (OS) were examined between bypass-first and EVT-first groups. The subjects in this study were 75 patients and 82 limbs in the bypass-first group and 24 patients and 24 limbs in the EVT-first group. The average age was higher in EVT-first group (P = 0.03). The percentage of inframalleolar bypass was higher in the EVT-first group (P = 0.002). Primary patency at 1 and 2 years was 72.0% and 67.5% for the bypass-first group and 53.1% and 47.2% for the EVT-first group, respectively (P = 0.04). Inframalleolar bypass was a risk factor for lower primary patency (hazard ratio 3.07, 95% confidence interval 1.18-8.51, P = 0.02) in multivariate analysis, while there were no differences in secondary patency, LS, AFS, and OS. Bypass surgery after EVT has lower primary patency rates in comparison with primary bypass in patients submitted to infrapopliteal revascularization. Although very heterogeneous study population with a lot of bias in the indication of the revascularization, LS, OS and AFS are not affected by previous EVT. Copyright © 2017 Elsevier Inc. All rights reserved.

Heat exchanger bypass system for an absorption refrigeration system

DOEpatents

Reimann, Robert C.

1984-01-01

A heat exchanger bypass system for an absorption refrigeration system is disclosed. The bypass system operates to pass strong solution from the generator around the heat exchanger to the absorber of the absorption refrigeration system when strong solution builds up in the generator above a selected level indicative of solidification of strong solution in the heat exchanger or other such blockage. The bypass system includes a bypass line with a gooseneck located in the generator for controlling flow of strong solution into the bypass line and for preventing refrigerant vapor in the generator from entering the bypass line during normal operation of the refrigeration system. Also, the bypass line includes a trap section filled with liquid for providing a barrier to maintain the normal pressure difference between the generator and the absorber even when the gooseneck of the bypass line is exposed to refrigerant vapor in the generator. Strong solution, which may accumulate in the trap section of the bypass line, is diluted, to prevent solidification, by supplying weak solution to the trap section from a purge system for the absorption refrigeration system.

Your diet after gastric bypass surgery

MedlinePlus

Gastric bypass surgery - your diet; Obesity - diet after bypass; Weight loss - diet after bypass ... et al. American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery ...

Exhaust gas bypass valve control for thermoelectric generator

DOEpatents

Reynolds, Michael G; Yang, Jihui; Meisner, Greogry P.; Stabler, Francis R.; De Bock, Hendrik Pieter Jacobus; Anderson, Todd Alan

2012-09-04

A method of controlling engine exhaust flow through at least one of an exhaust bypass and a thermoelectric device via a bypass valve is provided. The method includes: determining a mass flow of exhaust exiting an engine; determining a desired exhaust pressure based on the mass flow of exhaust; comparing the desired exhaust pressure to a determined exhaust pressure; and determining a bypass valve control value based on the comparing, wherein the bypass valve control value is used to control the bypass valve.

Linitis plastica of the bypassed stomach 7 years after Roux-en-Y gastric bypass: a case report.

PubMed

Haenen, Filip Wn; Gys, Ben; Moreels, Tom; Michielsen, Maartje; Gys, Tobie; Lafullarde, Thierry

2017-12-01

Laparoscopic Roux-en-Y gastric bypass (RYGB) is currently the preferred surgical procedure to treat morbid obesity. It has proven its effects on excess weight loss and its positive effect on comorbidities. One of the main issues, however, is the post-operative evaluation of the bypassed gastric remnant. In literature, cancer of the excluded stomach after RYGB is rare. We describe the case of a 52-year-old woman with gastric linitis plastica in the bypassed stomach after Roux-en-Y gastric bypass, diagnosed by means of laparoscopy and Single-Balloon enteroscopy, and it is clinical importance. Linitis plastica of the excluded stomach after RYGB is a very rare entity. This case report shows the importance of long-term post-operative follow-up, and the importance of single-balloon enteroscopy for visualization of the bypassed stomach remnant, when other investigations remain without results. This case report is only the second report of a linitis plastica in the bypassed stomach after Roux-en-Y gastric bypass.

Rural health care bypass behavior: how community and spatial characteristics affect primary health care selection.

PubMed

Sanders, Scott R; Erickson, Lance D; Call, Vaughn R A; McKnight, Matthew L; Hedges, Dawson W

2015-01-01

(1) To assess the prevalence of rural primary care physician (PCP) bypass, a behavior in which residents travel farther than necessary to obtain health care, (2) To examine the role of community and non-health-care-related characteristics on bypass behavior, and (3) To analyze spatial bypass patterns to determine which rural communities are most affected by bypass. Data came from the Montana Health Matters survey, which gathered self-reported information from Montana residents on their health care utilization, satisfaction with health care services, and community and demographic characteristics. Logistic regression and spatial analysis were used to examine the probability and spatial patterns of bypass. Overall, 39% of respondents bypass local health care. Similar to previous studies, dissatisfaction with local health care was found to increase the likelihood of bypass. Dissatisfaction with local shopping also increases the likelihood of bypass, while the number of friends in a community, and commonality with community reduce the likelihood of bypass. Other significant factors associated with bypass include age, income, health, and living in a highly rural community or one with high commuting flows. Our results suggest that outshopping theory, in which patients bundle services and shopping for added convenience, extends to primary health care selection. This implies that rural health care selection is multifaceted, and that in addition to perceived satisfaction with local health care, the quality of local shopping and levels of community attachment also influence bypass behavior. © 2014 National Rural Health Association.

Comparison between preoperative administration of methylprednisolone with its administration before and during congenital heart surgery on serum levels of IL-6 and IL-10.

PubMed

Abbasi Tashnizi, Mohammad; Soltani, Ghasem; Moeinipour, Ali Asghar; Ayatollahi, Hossein; Tanha, Amir Saber; Jarahi, Lida; Sepehri Shamloo, Alireza; Zirak, Nahid

2013-02-01

Steroid administration during cardiopulmonary bypass is considered to improve cardiopulmonary function by modulating inflammations caused by bypass. This study was performed to compare effectiveness of preoperative and intraoperative methylprednisolone (MP) to preoperative methylprednisolone alone in post bypass inflammatory (IL-6) and anti-inflammatory (IL-10) factors. Fifty pediatric patients undergoing cardiopulmonary bypass surgery from August 2011 to 2012 in the cardiac surgery department of Imam Reza Hospital, the major center for CPB, in Mashhad, Iran were randomly assigned to receive preoperative and intraoperative MP (30 mg/kg, 4 hours before bypass and in bypass prime, number 25) or preoperative MP only (30 mg/kg, number 25). Before and after bypass, four and 24 hours after bypass, serum IL-6 and IL-10 were measured by ELISA. In both groups, no significant difference with variation of expression for IL-6 (inflammatory factor) and IL-10 (anti-inflammatory factor) in different times after bypass was observed. No significant difference in reducing post bypass inflammation between preoperative steroid treatment and combined preoperative and intraoperative steroid administration reported and they had the same effects.

Comparison Between Preoperative Administration of Methylprednisolone With its Administration Before and During Congenital Heart Surgery on Serum Levels of IL-6 And IL-10

PubMed Central

Abbasi Tashnizi, Mohammad; Soltani, Ghasem; Moeinipour, Ali Asghar; Ayatollahi, Hossein; Tanha, Amir Saber; Jarahi, Lida; Sepehri Shamloo, Alireza; Zirak, Nahid

2013-01-01

Background Steroid administration during cardiopulmonary bypass is considered to improve cardiopulmonary function by modulating inflammations caused by bypass. Objectives This study was performed to compare effectiveness of preoperative and intraoperative methylprednisolone (MP) to preoperative methylprednisolone alone in post bypass inflammatory (IL-6) and anti-inflammatory (IL-10) factors. Patients and Methods Fifty pediatric patients undergoing cardiopulmonary bypass surgery from August 2011 to 2012 in the cardiac surgery department of Imam Reza Hospital, the major center for CPB, in Mashhad, Iran were randomly assigned to receive preoperative and intraoperative MP (30 mg/kg, 4 hours before bypass and in bypass prime, number 25) or preoperative MP only (30 mg/kg, number 25). Before and after bypass, four and 24 hours after bypass, serum IL-6 and IL-10 were measured by ELISA. Results In both groups, no significant difference with variation of expression for IL-6 (inflammatory factor) and IL-10 (anti-inflammatory factor) in different times after bypass was observed. Conclusions No significant difference in reducing post bypass inflammation between preoperative steroid treatment and combined preoperative and intraoperative steroid administration reported and they had the same effects. PMID:23682327

A Bayesian assessment of the effect of highway bypasses in Iowa on crashes and crash rate.

PubMed

Cena, Lorenzo G; Keren, Nir; Li, Wen; Carriquiry, Alicia L; Pawlovich, Michael D; Freeman, Steven A

2011-08-01

A common contention is that the construction of highway bypasses negatively impacts the economy of local communities by reducing pass-by traffic for businesses. However, as access to specific business' account records is limited, this impact is difficult to quantify. Another common contention is that bypasses contribute to a reduction in overall crashes in the community and in the surrounding areas. Even though a large number of bypasses have been constructed in the State of Iowa over the past several years, their actual impact in terms of traffic safety has not been quantified. This study seeks answers to the following questions: (a) Are bypasses in Iowa associated with a reduction in crash frequencies and crash rates on the bypassed highway? (b) Do bypasses in Iowa introduce a reduction of overall crash frequencies and rates or do they merely shift crashes from the highways through the communities to the bypasses with no significant overall reduction? We obtained crash information from the Iowa DOT at 19 sites on which a bypass was constructed sometime during the past 23 years. We also obtained the same information at six sites used as comparison sites on which no bypasses were constructed at least until 2005. We them employed a Bayesian approach to estimating the association between the construction of the bypass and crash rates, while also accounting for other factors. The construction of bypasses in Iowa is associated with a significant increase in traffic safety both on the main road through town and on the combined main road and bypass roadway. Copyright © 2011 National Safety Council and Elsevier Ltd. All rights reserved.

Long-term results of in situ saphenous vein bypass. Analysis of 2058 cases.

PubMed Central

Shah, D M; Darling, R C; Chang, B B; Fitzgerald, K M; Paty, P S; Leather, R P

1995-01-01

OBJECTIVE: The authors evaluated the long-term patency and outcome of patients undergoing infrainguinal reconstruction using the in situ saphenous vein. SUMMARY BACKGROUND DATA: The in situ saphenous vein bypass has demonstrated excellent patency and limb salvage rates in numerous studies. The authors previously reported their early results with these bypass procedures, and this article represents their long-term experience with 2058 in situ saphenous vein bypasses during a 20-year period. This comprises the largest series with long-term follow-up of in situ saphenous vein bypasses in the literature. METHODS: From 1975 to 1995, 3148 autogenous vein bypasses were performed at the authors' institution, of which 2058 used the saphenous vein in situ. The indication for operation was limb-threatening ischemia in 1875 of 2058 patients (91%). In 88% of patients with an intact ipsilateral saphenous vein, an in situ bypass was completed successfully. One thousand twenty-three bypasses (69%) were terminated at the infrapopliteal level. Of these bypasses, 1562 of 2058 (76%) were completed using the closed in situ technique. RESULTS: The 30-day patency rate was 96%, and the cumulative secondary patency was 91%, 81%, and 70% at 1, 5, and 10 years, respectively. Limb salvage rates using the in situ bypass were 97%, 95%, and 90% at 1, 5, and 10 years, respectively. CONCLUSION: The infrainguinal inflow source, length of bypass, specific outflow vessel, or vein diameter did not have a significant effect on immediate or long-term bypass performance. These data suggest that the in situ saphenous vein is an excellent conduit for femoropopliteal and femoral to infrageniculate bypasses for limb salvage. PMID:7574925

California bypass study : the economic impacts of bypasses.

DOT National Transportation Integrated Search

2006-05-01

The California Department of Transportation (Caltrans) sponsored the California : Bypass Study to improve basic knowledge about the impacts of bypasses on small-town : economies. The study included an investigation into the economic impacts of recent...

Combined direct and indirect bypass for moyamoya: quantitative assessment of direct bypass flow over time.

PubMed

Amin-Hanjani, Sepideh; Singh, Amritha; Rifai, Hashem; Thulborn, Keith R; Alaraj, Ali; Aletich, Victor; Charbel, Fady T

2013-12-01

The optimal revascularization strategy for symptomatic adult moyamoya remains controversial. Whereas direct bypass offers immediate revascularization, indirect bypass can effectively induce collaterals over time. Using angiography and quantitative magnetic resonance angiography, we examined the relative contributions of direct and indirect bypass in moyamoya patients after combined direct superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass and indirect encephaloduroarteriosynangiosis (EDAS). A retrospective review of moyamoya patients undergoing combined STA-MCA bypass and EDAS was conducted, excluding pediatric patients and hemorrhagic presentation. Patients with quantitative magnetic resonance angiography measurements of the direct bypass immediately and > 6 months postoperatively were included. Angiographic follow-up, when available, was used to assess EDAS collaterals at similar time intervals. Of 16 hemispheres in 13 patients, 11 (69%) demonstrated a significant (> 50%) decline in direct bypass flow at > 6 months compared with baseline, averaging a drop from 99 ± 35 to 12 ± 7 mL/min. Conversely, angiography in these hemispheres demonstrated prominent indirect collaterals, in concert with shrinkage of the STA graft. Decline in flow was apparent at a median of 9 months but was evident as early as 2 to 3 months. In this small cohort, a reciprocal relationship between direct STA bypass flow and indirect EDAS collaterals frequently occurred. This substantiates the notion that combined direct/indirect bypass can provide temporally complementary revascularization.

Variable volume combustor with an air bypass system

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

Johnson, Thomas Edward; Ziminsky, Willy Steve; Ostebee, Heath Michael

The present application provides a combustor for use with flow of fuel and a flow of air in a gas turbine engine. The combustor may include a number of micro-mixer fuel nozzles positioned within a liner and an air bypass system position about the liner. The air bypass system variably allows a bypass portion of the flow of air to bypass the micro-mixer fuel nozzles.

Outcomes of Mini vs Roux-en-Y gastric bypass: A meta-analysis and systematic review.

PubMed

Wang, Fu-Gang; Yan, Wen-Mao; Yan, Ming; Song, Mao-Min

2018-05-10

Mini gastric bypass has been proved to be capable of achieving excellent metabolic results by numerous published studies. Compared to Roux-en-Y gastric bypass, mini gastric bypass is a technically simpler and reversible procedure. However, comparative outcomes of the effectiveness between Mini gastric bypass and Roux-en-Y gastric bypass remain unclear. A systematic literature search was performed in Pubmed, Embase, Cochrane library from inception to February 9, 2018. For assessment of method quality, NOS (Newcastle-Ottawa Scale) and Cochrane Collaboration's tool for assessing risk of bias were used for cohort study and randomized controlled trials, respectively. The meta-analysis was performed by RevMan 5.3 software. 10 cohort studies and 1 randomized controlled trial was included in our meta-analysis. The method quality of the 10 cohort studies was proved as high quality according to the Newcastle-Ottawa Scale. The randomized controlled trial was proved to have a low risk of bias according to Cochrane Collaboration's assessment. Patients receiving mini-gastric bypass had multiple advantageous indexes as compared with patients receiving Roux-en-Y gastric bypass. Examples include: a higher 1-year EWL% (P < 0.05), higher 2-year EWL% (P < 0.05), higher type 2 diabetes mellitus remission rate, as well as a shorter operation time (P < 0.05). No significant statistical difference was observed in hypertension remission rate, mortality, leakage rate, GERD rate, or hospital stay between mini gastric bypass and Roux-en-Y gastric bypass. Mini gastric bypass seems to be a simpler procedure with a better weight reduction effect. This seems to also be the case regarding remission rates of type 2 diabetes mellitus when using Mini gastric bypass in comparison to Roux-en-Y gastric bypass. A small sample size and biased data may have influenced the stability of our results. In light of this, surgeons should treat our results in a conservative way. Larger sample size and multi-center randomized control trials are needed to compare the effectiveness and safety between mini-gastric bypass and Roux-en-Y gastric bypass. Copyright © 2018. Published by Elsevier Ltd.

Synergistic Interactions Between Direct and Indirect Bypasses in Combined Procedures: The Significance of Indirect Bypasses in Moyamoya Disease.

PubMed

Uchino, Haruto; Kim, Jae-Hoon; Fujima, Noriyuki; Kazumata, Ken; Ito, Masaki; Nakayama, Naoki; Kuroda, Satoshi; Houkin, Kiyohiro

2017-02-01

Whether additional indirect bypasses effectively contribute to revascularization in combined procedures remains unclear in patients with moyamoya disease. To evaluate the longitudinal changes associated with combined procedures while following up pediatric and adult patients long term and to assess whether any other clinical factors or hemodynamic parameters affected these changes to determine an optimal surgical strategy. We studied 58 hemispheres in 43 adults and 39 hemispheres in 26 children who underwent combined revascularization for moyamoya disease. To evaluate bypass development, we assessed the sizes of the superficial temporal artery and middle meningeal artery using magnetic resonance angiography. Multivariate analysis determined the effects of multiple variables on bypass development. Indirect bypass (middle meningeal artery) development occurred in 95% and 78% of the pediatric and adult hemispheres, respectively. Of these, dual development of direct and indirect bypasses occurred in 54% of the pediatric hemispheres and in 47% of the adult hemispheres. Reciprocal superficial temporal artery regression occurred in 28% of the hemispheres during the transition from the postoperative acute phase to the chronic phase during indirect bypass development. Good indirect bypass development was associated with adult hemispheres at Suzuki stage 4 or greater (odds ratio, 7.4; 95% confidence interval, 1.4-39.4; P = .02). Disease onset type and preoperative hemodynamic parameters were not considered predictors for the development of surgical revascularization. Simultaneous direct and indirect bypass development was most frequently observed, regardless of patient age and hemodynamic status. Applying indirect bypass as an adjunct to direct bypass could maximize revascularization in adults and children.

Robotic totally endoscopic triple coronary artery bypass grafting on the arrested heart: report of the first successful clinical case.

PubMed

Bonatti, Johannes; Rehman, Atiq; Schwartz, Kimberly; Deshpande, Seema; Kon, Zachary; Lehr, Eric; Zimrin, David; Griffith, Bartley

2010-12-01

Robotic technology enables "port only" totally endoscopic coronary artery bypass grafting (TECAB). During early procedure development only single bypass grafts were feasible. Because current referral practice for coronary bypass surgery mostly includes multivessel disease, performance of multiple endoscopic bypass grafts is desirable. We report a case in which a patient received a right internal mammary artery bypass graft to the left anterior descending artery and a left internal mammary artery jump graft to 2 obtuse marginal branches. The procedure was performed through 5 ports on the arrested heart using the daVinci S robotic surgical system. This is the first reported triple bypass grafting procedure using an arrested heart approach.

Coronary–Coronary Bypass

PubMed Central

Erdil, Nevzat; Ates, Sanser; Demirkilic, Ufuk; Tatar, Harun; Sag, Cemal

2002-01-01

There is increased risk of systemic embolism during cardiopulmonary bypass in patients with a severely atherosclerotic ascending aorta. We report a coronary–coronary bypass in a 74-year-old man with a porcelain aorta. He underwent a proximal right coronary–distal right coronary artery bypass with a saphenous vein graft, combined with a pedicled arterial graft (left internal mammary artery) to the left anterior descending artery, in the presence of a beating heart without cardiopulmonary bypass. The patient survived without evidence of perioperative myocardial infarction or cerebrovascular accident. One year later, follow-up angiography showed graft patency with good distal runoff. Coronary–coronary bypass on a beating heart without cardiopulmonary bypass can be performed safely in a patient with porcelain aorta. (Tex Heart Inst J 2002;29:54–5) PMID:11995853

Variable mixer propulsion cycle

NASA Technical Reports Server (NTRS)

Rundell, D. J.; Mchugh, D. P.; Foster, T.; Brown, R. H. (Inventor)

1978-01-01

A design technique, method and apparatus are delineated for controlling the bypass gas stream pressure and varying the bypass ratio of a mixed flow gas turbine engine in order to achieve improved performance. The disclosed embodiments each include a mixing device for combining the core and bypass gas streams. The variable area mixing device permits the static pressures of the core and bypass streams to be balanced prior to mixing at widely varying bypass stream pressure levels. The mixed flow gas turbine engine therefore operates efficiently over a wide range of bypass ratios and the dynamic pressure of the bypass stream is maintained at a level which will keep the engine inlet airflow matched to an optimum design level throughout a wide range of engine thrust settings.

Turbine and superheater bypass evaluation. Final report. [Faster startup in cycling operation and less erosion with steam bypass systems, including bypass design

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

Rosard, D.D.; Steltz, W.G.

1986-10-01

Properly sized turbine and boiler bypass systems permit two-shift cycling operation of units, shorten start-up time, and reduce life expenditures of plant components. With bypasses installed, faster startups can reduce fuel costs by $100,000 per year for a typical 500-MW fossil-fired unit. This report discusses the technical characteristics of existing bypass systems and provides guidelines for sizing bypass systems to achieve economical and reliable two-shift operation. The collection and analysis of startup data from several generating units were used in conjunction with computer simulations to illustrate the effects of adding various arrangements and sizes of steam bypass systems. The report,more » which indicates that shutdown procedures have significant impact on subsequent startup and loading time, describes operating practices to optimize the effectiveness of bypass systems. To determine the effectiveness of large turbine bypass systems of less than 100% capacity in preventing boiler trips following load rejection, transient field data were compared to a load rejection simulation using the modular modeling system (MMS). The MMS was then used to predict system response to other levels of load rejection. 7 refs., 87 figs., 8 tabs.« less

Low Morbidity after Extracranial-Intracranial Bypass Operation. The Danish Extracranial-Intracranial Bypass Study: A Nationwide Survey.

PubMed

von Weitzel-Mudersbach, Paul; Andersen, Grethe; Rosenbaum, Sverre

2018-06-07

Patients with symptomatic atherosclerotic carotid artery occlusion (SACAO) have a high risk of a recurrent stroke. Extracranial-intracranial bypass (EC-IC bypass) has been shown not to improve outcome compared with medical treatment alone because long-term prevention of recurrent stroke in operated patients was offset by high perioperative stroke rates. We report our experience with EC-IC bypass operated at an experienced high-volume centre. We conducted a nationwide observational study of EC-IC bypass patients operated in the years 2007-2016 due to SACAO with ongoing clinical symptoms or progression on MRI and severe haemodynamic failure (SHF). Perioperative stroke and death within 30 days after the operation, ipsilateral stroke, bypass patency, transient ischaemic attack, and all-stroke events and deaths during long-term follow-up were registered prospectively. EC-IC bypass was performed in 48 patients with SHF and SACAO. The mean age was 64 (45-83) years. The mean follow-up was 3.6 years. The stroke rate after 30 days was 4.2%. No further ipsilateral strokes occurred during follow-up. Clinical symptoms arrested in all patients. Bypass patency rate was 94%. The perioperative stroke rate in EC-IC bypass operation, performed at a highly experienced centre, was low. During long-term follow-up, no ipsilateral stroke occurred. Consequently, EC-IC-bypass should still be considered for selected patients with SACAO, if operation can be carried out in experienced centres with low perioperative morbidity. © 2018 S. Karger AG, Basel.

Poppet valve control of throat stability bypass to increase stable airflow range of a Mach 2.5. inlet with 60 percent internal contraction

NASA Technical Reports Server (NTRS)

Mitchell, G. A.; Sanders, B. W.

1975-01-01

The throat of a Mach 2.5 inlet with a coldpipe termination was fitted with a stability-bypass system. System variations included several stability bypass entrance configurations. Poppet valves controlled the bypass airflow. The inlet stable airflow range achieved with each configuration was determined for both steady state conditions and internal pulse transients. Results are compared with those obtained without a stability bypass system. Transient results were also obtained for the inlet with a choke point at the diffuser exit and for the inlet with large and small stability bypass plenum volumes. Poppet valves at the stability bypass exit provided the inlet with a stable airflow range of 20 percent or greater at all static and transient conditions.

Combination Superficial Temporal Artery-Middle Cerebral Artery Bypass and M2-M2 Reanastomosis With Trapping of a Stented Distal Middle Cerebral Artery Aneurysm: 3-Dimensional Operative Video.

PubMed

Burkhardt, Jan-Karl; Yousef, Sonia; Tabani, Halima; Benet, Arnau; Rubio, Roberto Rodriguez; Lawton, Michael T

2018-05-12

Distal middle cerebral artery (MCA) aneurysms often have non-saccular morphology and cannot be clipped, requiring revascularization and trapping instead. Combination bypasses are needed when 2 arteries exit the aneurysm, and extracranial-intracranial and intracranial-intracranial bypasses can be used. This video demonstrates a combination bypass used to treat a previously stented distal MCA aneurysm with both a superficial temporal artery (STA)-to-MCA bypass and an M2-to-M2 reanastomosis. This 56-yr-old man presented with distal left-sided MCA aneurysm 2 years earlier and attempted stent-assisted coiling was aborted after the aneurysm was perforated with stenting alone. Follow-up angiography demonstrated progressive aneurysm enlargement, and he was referred for surgery. The patient consented for the procedure and a pterional craniotomy extended posteriorly exposed the distal Sylvian fissure and efferent M4-cortical arteries. After splitting the Sylvian fissure, the "flash fluorescence" technique with indocyanine green (ICG) videoangiography identified an M4 recipient artery from the deeper of 2 exiting branches for STA-MCA bypass.1 The aneurysm was then trapped, and inflow and the more superficial outflow arteries were anastomosed end to end (M2-M2 in-situ bypass). A platelet plug that developed at the reanastomosis site was broken apart with mechanical manipulation, and ICG videoangiography demonstrated patency of both bypasses. The patient recovered without any neurological deficits, and postoperative computed tomography angiography confirmed bypass patency. Combination bypasses are needed when unclippable bifurcation aneurysms require revascularization. Careful intraoperative evaluation of patency of the bypass is imperative and helps identifying and addressing any potential early bypass occlusion.

Role of cytokine hemoadsorption in cardiopulmonary bypass-induced ventricular dysfunction in a porcine model.

PubMed

Vocelka, Craig R; Jones, Krystal M; Mikhova, Krasimira M; Ebisu, Ryan M; Shar, Ashley; Kellum, John A; Verrier, Edward D; Rabkin, David G

2013-12-01

Little is known about the effect of cardiopulmonary bypass alone on cardiac function; in an attempt to illuminate this relationship and test a possible mechanism, we used Cytosorb, a device capable of removing virtually all types of circulating cytokines to test the hypothesis that hemoadsorption of cytokines during bypass attenuates bypass-induced acute organ dysfunction. Twelve Yorkshire pigs (50-65 kg) were instrumented with a left ventricular conductance catheter. Baseline mechanics and cytokine expression (tumor necrosis factor [TNF], interleukin-6 [IL-6], and interleukin-10) were measured before and hourly after 1 hour of normothermic cardiopulmonary bypass. Animals underwent bypass without (cardiopulmonary bypass [CPB], n = 6) or with (CPB+HA, n = 6) the CytosorbTM device. Data were compared with "historical" controls (n = 6) that were similarly instrumented but underwent observation instead of bypass. Five hours after separation from bypass (or observation), animals were euthanized. Myocardial water content was determined postmortem. Neither TNF nor IL-6 was significantly elevated in either experimental group versus controls at any time point. Preload recruitable stroke work and dP/dtmax were significantly depressed immediately after separation from bypass in both CPB+HA and CPB and remained depressed for the duration of the experiment. Although Tau remained unchanged, dP/dTmin was significantly diminished in both bypass groups at all time points after separation from bypass. Cytokine hemoadsorption had no effect on any measurable index of function. Differences in postmortem data were not evident between groups. One hour of normothermic CPB results in a significant and sustained decline in left ventricular function that appears unrelated to changes in cytokine expression. Because we did not appreciate a significant change in cytokine concentrations postbypass, the capacity of cytokine hemoadsorption to attenuate CPB-induced ventricular dysfunction could not be assessed.

Isolated Human Pulmonary Artery Structure and Function Pre- and Post-Cardiopulmonary Bypass Surgery.

PubMed

Dora, Kim A; Stanley, Christopher P; Al Jaaly, Emad; Fiorentino, Francesca; Ascione, Raimondo; Reeves, Barnaby C; Angelini, Gianni D

2016-02-23

Pulmonary dysfunction is a known complication after cardiac surgery using cardiopulmonary bypass, ranging from subclinical functional changes to prolonged postoperative ventilation, acute lung injury, and acute respiratory distress syndrome. Whether human pulmonary arterial function is compromised is unknown. The aim of the present study was to compare the structure and function of isolated and cannulated human pulmonary arteries obtained from lung biopsies after the chest was opened (pre-cardiopulmonary bypass) to those obtained at the end of cardiopulmonary bypass (post-cardiopulmonary bypass) from patients undergoing coronary artery bypass graft surgery. Pre- and post-cardiopulmonary bypass lung biopsies were received from 12 patients undergoing elective surgery. Intralobular small arteries were dissected, cannulated, pressurized, and imaged using confocal microscopy. Functionally, the thromboxane mimetic U46619 produced concentration-dependent vasoconstriction in 100% and 75% of pre- and post-cardiopulmonary bypass arteries, respectively. The endothelium-dependent agonist bradykinin stimulated vasodilation in 45% and 33% of arteries pre- and post-cardiopulmonary bypass, respectively. Structurally, in most arteries smooth muscle cells aligned circumferentially; live cell viability revealed that although 100% of smooth muscle and 90% of endothelial cells from pre-cardiopulmonary bypass biopsies had intact membranes and were considered viable, only 60% and 58%, respectively, were viable from post-cardiopulmonary bypass biopsies. We successfully investigated isolated pulmonary artery structure and function in fresh lung biopsies from patients undergoing heart surgery. Pulmonary artery contractile tone and endothelium-dependent dilation were significantly reduced in post-cardiopulmonary bypass biopsies. The decreased functional responses were associated with reduced cell viability. URL: http://www.isrctn.com/ISRCTN34428459. Unique identifier: ISRCTN 34428459. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Surgical outcomes for moyamoya angiopathy at barrow neurological institute with comparison of adult indirect encephaloduroarteriosynangiosis bypass, adult direct superficial temporal artery-to-middle cerebral artery bypass, and pediatric bypass: 154 revascularization surgeries in 140 affected hemispheres.

PubMed

Abla, Adib A; Gandhoke, Gurpreet; Clark, Justin C; Oppenlander, Mark E; Velat, Gregory J; Zabramski, Joseph M; Albuquerque, Felipe C; Nakaji, Peter; Spetzler, Robert F; Wanebo, John E

2013-09-01

Untreated, moyamoya angiopathy is a progressive vaso-occlusive process that can lead to ischemic or hemorrhagic stroke. To review 1 institution's surgical experience with both direct and indirect bypass (encephaloduroarteriosynangiosis) in adult and pediatric groups. A retrospective review was conducted of a consecutive series of patients treated for moyamoya angiopathy between 1995 and 2009. Thirty-nine adult patients underwent indirect bypass as their initial therapy; 29 adult patients underwent direct bypass. Twenty-four pediatric patients included 20 indirect bypasses and 4 direct bypasses. Overall, 140 hemispheres were treated; 48 patients received revascularization of both hemispheres. There were 14 additional revascularization procedures (10% per hemisphere) performed over a site of continued hypoperfusion postoperatively. Fourteen postoperative ischemic strokes occurred during the entire follow-up (10% per hemisphere), and the Kaplan-Meier analysis was not significantly different between groups (P = .59). Four grafts (9.09%) had failed at radiographic follow-up of the 44 direct bypasses performed. Before the initial surgery, the modified Rankin Scale score was 1.58 ± 0.93, 1.48 ± 0.74, and 1.8 ± 1.1 in the pediatric, adult direct, and adult indirect groups (P = .39). At last follow-up, it was 1.29 ± 1.31, 1.09 ± 0.90, and 1.94 ± 1.51 (P = .04) in the pediatric, adult direct, and adult indirect groups. This series demonstrates that both direct and indirect bypasses can be equally effective in preventing stroke. However, in adult patients, direct bypass patients had significantly greater improvement in symptoms, as seen in modified Rankin Scale scores. Pediatric patients, despite undergoing predominantly indirect bypasses, fared roughly the same as the adults in the direct bypass group.

21 CFR 870.4430 - Cardiopulmonary bypass intracardiac suction control.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass intracardiac suction control. 870.4430 Section 870.4430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND....4430 Cardiopulmonary bypass intracardiac suction control. (a) Identification. A cardiopulmonary bypass...

21 CFR 870.4250 - Cardiopulmonary bypass temperature controller.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass temperature controller. 870.4250 Section 870.4250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller...

21 CFR 870.4430 - Cardiopulmonary bypass intracardiac suction control.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass intracardiac suction control. 870.4430 Section 870.4430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND....4430 Cardiopulmonary bypass intracardiac suction control. (a) Identification. A cardiopulmonary bypass...

21 CFR 870.4250 - Cardiopulmonary bypass temperature controller.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass temperature controller. 870.4250 Section 870.4250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller...

Temporary bypass for superior vena cava reconstruction with Anthron bypass tubeTM

PubMed Central

Yamasaki, Naoya; Tsuchiya, Tomoshi; Miyazaki, Takuro; Kamohara, Ryotaro; Hatachi, Go; Nagayasu, Takeshi

2017-01-01

Total superior vena cava (SVC) clamping for SVC replacement or repair can be used in thoracic surgery. A bypass technique is an option to avoid hemodynamic instability and cerebral venous hypertension and hypoperfusion. The present report describes a venous bypass technique using Anthron bypass tubeTM for total SVC clamping. Indications for this procedure include the need for a temporary bypass between the brachiocephalic vein and atrium for complete tumor resection. This procedure allows the surgeons sufficient time to complete replacement of SVC or partial resection of SVC without adverse effects. Further, it is a relatively simple procedure requiring minimal time. PMID:28840027

Follow-up of renal and mesenteric artery revascularization with duplex ultrasonography

PubMed Central

Taylor, David C.; Houston, Gordon T.M.; Anderson, Caroline; Jameson, Margot; Popatia, Shelley

1996-01-01

Objective To evaluate the long-term anatomic results of renal revascularization procedures using duplex ultrasonography. Design A case series. Setting A university-affiliated hospital. Patients Twenty-five patients who had undergone renal percutaneous transluminal angioplasty (PTA) (18 arteries), renal bypass (10 arteries) and mesenteric bypass (6 arteries). The mean follow-up was 22 months (range from 3 to 48 months) for those who underwent renal PTA, 23 months (range from 1.5 to 70 months) for those who underwent renal bypass and 34 months (range from 8 to 144 months) for those who underwent mesenteric bypass. Main Outcome Measures Patency rates for the three procedures as assessed by duplex ultrasonography. Results Duplex ultrasonography demonstrated patency without stenosis after renal and mesenteric artery revascularization in 14 arteries subjected to renal PTA, 9 arteries subjected to renal bypass and 6 arteries subjected to mesenteric bypass. Three arteries that had renal PTA had recurrent vessel stenosis and one had occlusion. One artery that had renal bypass showed occlusion. Conclusions Renal PTA, renal bypass and mesenteric bypass are durable procedures at 2 years of follow-up, and duplex ultrasonography is a valuable method for assessing the patency of arteries after renal and mesenteric revascularization. PMID:8599785

21 CFR 870.4250 - Cardiopulmonary bypass temperature controller.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass temperature controller. 870... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller is a device used to control the temperature of the fluid entering and leaving a heat exchanger. (b...

21 CFR 870.4250 - Cardiopulmonary bypass temperature controller.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass temperature controller. 870... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller is a device used to control the temperature of the fluid entering and leaving a heat exchanger. (b...

21 CFR 870.4250 - Cardiopulmonary bypass temperature controller.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass temperature controller. 870... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller is a device used to control the temperature of the fluid entering and leaving a heat exchanger. (b...

Genome wide interactions of wild-type and activator bypass forms of σ54.

PubMed

Schaefer, Jorrit; Engl, Christoph; Zhang, Nan; Lawton, Edward; Buck, Martin

2015-09-03

Enhancer-dependent transcription involving the promoter specificity factor σ(54) is widely distributed amongst bacteria and commonly associated with cell envelope function. For transcription initiation, σ(54)-RNA polymerase yields open promoter complexes through its remodelling by cognate AAA+ ATPase activators. Since activators can be bypassed in vitro, bypass transcription in vivo could be a source of emergent gene expression along evolutionary pathways yielding new control networks and transcription patterns. At a single test promoter in vivo bypass transcription was not observed. We now use genome-wide transcription profiling, genome-wide mutagenesis and gene over-expression strategies in Escherichia coli, to (i) scope the range of bypass transcription in vivo and (ii) identify genes which might alter bypass transcription in vivo. We find little evidence for pervasive bypass transcription in vivo with only a small subset of σ(54) promoters functioning without activators. Results also suggest no one gene limits bypass transcription in vivo, arguing bypass transcription is strongly kept in check. Promoter sequences subject to repression by σ(54) were evident, indicating loss of rpoN (encoding σ(54)) rather than creating rpoN bypass alleles would be one evolutionary route for new gene expression patterns. Finally, cold-shock promoters showed unusual σ(54)-dependence in vivo not readily correlated with conventional σ(54) binding-sites. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Genome wide interactions of wild-type and activator bypass forms of σ54

PubMed Central

Schaefer, Jorrit; Engl, Christoph; Zhang, Nan; Lawton, Edward; Buck, Martin

2015-01-01

Enhancer-dependent transcription involving the promoter specificity factor σ54 is widely distributed amongst bacteria and commonly associated with cell envelope function. For transcription initiation, σ54-RNA polymerase yields open promoter complexes through its remodelling by cognate AAA+ ATPase activators. Since activators can be bypassed in vitro, bypass transcription in vivo could be a source of emergent gene expression along evolutionary pathways yielding new control networks and transcription patterns. At a single test promoter in vivo bypass transcription was not observed. We now use genome-wide transcription profiling, genome-wide mutagenesis and gene over-expression strategies in Escherichia coli, to (i) scope the range of bypass transcription in vivo and (ii) identify genes which might alter bypass transcription in vivo. We find little evidence for pervasive bypass transcription in vivo with only a small subset of σ54 promoters functioning without activators. Results also suggest no one gene limits bypass transcription in vivo, arguing bypass transcription is strongly kept in check. Promoter sequences subject to repression by σ54 were evident, indicating loss of rpoN (encoding σ54) rather than creating rpoN bypass alleles would be one evolutionary route for new gene expression patterns. Finally, cold-shock promoters showed unusual σ54-dependence in vivo not readily correlated with conventional σ54 binding-sites. PMID:26082500

Aerodynamic/acoustic performance of YJ101/double bypass VCE with coannular plug nozzle

NASA Technical Reports Server (NTRS)

Vdoviak, J. W.; Knott, P. R.; Ebacker, J. J.

1981-01-01

Results of a forward Variable Area Bypass Injector test and a Coannular Nozzle test performed on a YJ101 Double Bypass Variable Cycle Engine are reported. These components are intended for use on a Variable Cycle Engine. The forward Variable Area Bypass Injector test demonstrated the mode shifting capability between single and double bypass operation with less than predicted aerodynamic losses in the bypass duct. The acoustic nozzle test demonstrated that coannular noise suppression was between 4 and 6 PNdB in the aft quadrant. The YJ101 VCE equipped with the forward VABI and the coannular exhaust nozzle performed as predicted with exhaust system aerodynamic losses lower than predicted both in single and double bypass modes. Extensive acoustic data were collected including far field, near field, sound separation/ internal probe measurements as Laser Velocimeter traverses.

21 CFR 870.4290 - Cardiopulmonary bypass adaptor, stopcock, manifold, or fitting.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass adaptor, stopcock, manifold... Devices § 870.4290 Cardiopulmonary bypass adaptor, stopcock, manifold, or fitting. (a) Identification. A cardiopulmonary bypass adaptor, stopcock, manifold, or fitting is a device used in cardiovascular diagnostic...

21 CFR 870.4210 - Cardiopulmonary bypass vascular catheter, cannula, or tubing.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass vascular catheter, cannula... Devices § 870.4210 Cardiopulmonary bypass vascular catheter, cannula, or tubing. (a) Identification. A cardiopulmonary bypass vascular catheter, cannula, or tubing is a device used in cardiopulmonary surgery to...

21 CFR 870.4300 - Cardiopulmonary bypass gas control unit.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass gas control unit. 870.4300... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Surgical Devices § 870.4300 Cardiopulmonary bypass gas control unit. (a) Identification. A cardiopulmonary bypass gas control unit is a device used...

21 CFR 870.4210 - Cardiopulmonary bypass vascular catheter, cannula, or tubing.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass vascular catheter, cannula... Devices § 870.4210 Cardiopulmonary bypass vascular catheter, cannula, or tubing. (a) Identification. A cardiopulmonary bypass vascular catheter, cannula, or tubing is a device used in cardiopulmonary surgery to...

21 CFR 870.4300 - Cardiopulmonary bypass gas control unit.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass gas control unit. 870.4300... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Surgical Devices § 870.4300 Cardiopulmonary bypass gas control unit. (a) Identification. A cardiopulmonary bypass gas control unit is a device used...

21 CFR 870.4290 - Cardiopulmonary bypass adaptor, stopcock, manifold, or fitting.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass adaptor, stopcock, manifold... Devices § 870.4290 Cardiopulmonary bypass adaptor, stopcock, manifold, or fitting. (a) Identification. A cardiopulmonary bypass adaptor, stopcock, manifold, or fitting is a device used in cardiovascular diagnostic...

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

21 CFR 870.4360 - Nonroller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nonroller-type cardiopulmonary bypass blood pump... Nonroller-type cardiopulmonary bypass blood pump. (a) Identification. A nonroller-type cardiopulmonary bypass blood pump is a device that uses a method other than revolving rollers to pump the blood through...

21 CFR 870.4360 - Nonroller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nonroller-type cardiopulmonary bypass blood pump... Nonroller-type cardiopulmonary bypass blood pump. (a) Identification. A nonroller-type cardiopulmonary bypass blood pump is a device that uses a method other than revolving rollers to pump the blood through...

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

21 CFR 870.4360 - Nonroller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nonroller-type cardiopulmonary bypass blood pump... Nonroller-type cardiopulmonary bypass blood pump. (a) Identification. A nonroller-type cardiopulmonary bypass blood pump is a device that uses a method other than revolving rollers to pump the blood through...

21 CFR 870.4370 - Roller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Roller-type cardiopulmonary bypass blood pump. 870... Roller-type cardiopulmonary bypass blood pump. (a) Identification. A roller-type cardiopulmonary bypass blood pump is a device that uses a revolving roller mechanism to pump the blood through the...

21 CFR 870.4360 - Nonroller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nonroller-type cardiopulmonary bypass blood pump... Nonroller-type cardiopulmonary bypass blood pump. (a) Identification. A nonroller-type cardiopulmonary bypass blood pump is a device that uses a method other than revolving rollers to pump the blood through...

21 CFR 870.4360 - Nonroller-type cardiopulmonary bypass blood pump.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nonroller-type cardiopulmonary bypass blood pump... Nonroller-type cardiopulmonary bypass blood pump. (a) Identification. A nonroller-type cardiopulmonary bypass blood pump is a device that uses a method other than revolving rollers to pump the blood through...

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass heat exchanger. 870.4240... bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of a heat exchange system used in extracorporeal circulation to warm or cool the blood or...

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass heat exchanger. 870.4240... bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of a heat exchange system used in extracorporeal circulation to warm or cool the blood or...

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass heat exchanger. 870.4240... bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of a heat exchange system used in extracorporeal circulation to warm or cool the blood or...

21 CFR 870.4260 - Cardiopulmonary bypass arterial line blood filter.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass arterial line blood filter... Cardiopulmonary bypass arterial line blood filter. (a) Identification. A cardiopulmonary bypass arterial line blood filter is a device used as part of a gas exchange (oxygenator) system to filter nonbiologic...

21 CFR 870.4260 - Cardiopulmonary bypass arterial line blood filter.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass arterial line blood filter... Cardiopulmonary bypass arterial line blood filter. (a) Identification. A cardiopulmonary bypass arterial line blood filter is a device used as part of a gas exchange (oxygenator) system to filter nonbiologic...

21 CFR 870.4260 - Cardiopulmonary bypass arterial line blood filter.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass arterial line blood filter... Cardiopulmonary bypass arterial line blood filter. (a) Identification. A cardiopulmonary bypass arterial line blood filter is a device used as part of a gas exchange (oxygenator) system to filter nonbiologic...

21 CFR 870.4260 - Cardiopulmonary bypass arterial line blood filter.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass arterial line blood filter... Cardiopulmonary bypass arterial line blood filter. (a) Identification. A cardiopulmonary bypass arterial line blood filter is a device used as part of a gas exchange (oxygenator) system to filter nonbiologic...

21 CFR 870.4260 - Cardiopulmonary bypass arterial line blood filter.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass arterial line blood filter... Cardiopulmonary bypass arterial line blood filter. (a) Identification. A cardiopulmonary bypass arterial line blood filter is a device used as part of a gas exchange (oxygenator) system to filter nonbiologic...

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass heat exchanger. 870.4240... bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of a heat exchange system used in extracorporeal circulation to warm or cool the blood or...

21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass heat exchanger. 870.4240... bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of a heat exchange system used in extracorporeal circulation to warm or cool the blood or...

21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass bubble detector. 870.4205 Section 870.4205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to...

21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass bubble detector. 870.4205 Section 870.4205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to...

21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass bubble detector. 870.4205 Section 870.4205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to...

21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass bubble detector. 870.4205 Section 870.4205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to...

21 CFR 870.4205 - Cardiopulmonary bypass bubble detector.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass bubble detector. 870.4205 Section 870.4205 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to...

The experience of totally endoscopic coronary bypass grafting with the robotic system «Da Vinci» in Russia

NASA Astrophysics Data System (ADS)

Efendiev, V. U.; Alsov, S. A.; Ruzmatov, T. M.; Mikheenko, I. L.; Chernyavsky, A. M.; Malakhov, E. S.

2015-11-01

A new technology - a thoracoscopic coronary bypass grafting with the use of Da Vinci robotic system in Russia is represented by the experience of NRICP. The technology was introduced in Russia in 2011. Overall, one hundred endoscopic coronary artery bypass procedures were performed. We have compared and analyzed results of coronary artery stenting vs minimally invasive coronary artery bypass grafting. According to the results, totally endoscopic coronary artery bypass grafting has several advantages over alternative treatment strategies.

Intraoperative Evaluation of Reverse Bypass Using a Naturally Formed "Bonnet" Superficial Temporal Artery: Technical Note.

PubMed

Nagm, Alhusain; Horiuchi, Tetsuyoshi; Hasegawa, Takatoshi; Hongo, Kazuhiro

2016-04-01

In reverse bypass that used a naturally formed "bonnet" superficial temporal artery, intraoperative volume flow measurement quantifies flow augmentation after revascularization, confirms flow preservation, and identifies inadvertent vessel compromise. A 75-year-old man presented with transient ischemic attacks attributed to right internal carotid artery stenosis. He underwent successful reverse bypass via a naturally formed "bonnet" superficial temporal artery middle cerebral artery bypass. As the result of proper intraoperative volume flow evaluation, a successful reverse bypass was achieved. Modification of the intraoperative stroke risk and prediction of the long-term patency after reverse bypass can be achieved by meticulous intraoperative blood flow evaluation. Copyright © 2016 Elsevier Inc. All rights reserved.

Is Atherectomy the Best First-Line Therapy for Limb Salvage in Patients With Critical Limb Ischemia?

PubMed Central

Loor, Gabriel; Skelly, Christopher L.; Wahlgren, Carl-Magnus; Bassiouny, Hisham S.; Piano, Giancarlo; Shaalan, Wael

2010-01-01

Objective To determine the efficacy of atherectomy for limb salvage compared with open bypass in patients with critical limb ischemia. Methods Ninety-nine consecutive bypass and atherectomy procedures performed for critical limb ischemia between January 2003 and October 2006 were reviewed. Results A total of 99 cases involving TASC C (n = 43, 44%) and D (n = 56, 56%) lesions were treated with surgical bypass in 59 patients and atherectomy in 33 patients. Bypass and atherectomy achieved similar 1-year primary patency (64% vs 63%; P = .2). However, the 1-year limb salvage rate was greater in the bypass group (87% vs 69%; P = .004). In the tissue loss subgroup, there was a greater limb salvage rate for bypass patients versus atherectomy (79% vs 60%; P = .04). Conclusions Patients with critical limb ischemia may do better with open bypass compared with atherectomy as first-line therapy for limb salvage. PMID:19640919

21 CFR 870.4220 - Cardiopulmonary bypass heart-lung machine console.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass heart-lung machine console... Cardiopulmonary bypass heart-lung machine console. (a) Identification. A cardiopulmonary bypass heart-lung machine... heart-lung machine. The console is designed to interface with the basic units used in a gas exchange...

21 CFR 870.4410 - Cardiopulmonary bypass in-line blood gas sensor.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass in-line blood gas sensor... Cardiopulmonary bypass in-line blood gas sensor. (a) Identification. A cardiopulmonary bypass in-line blood gas sensor is a transducer that measures the level of gases in the blood. (b) Classification. Class II...

21 CFR 870.4410 - Cardiopulmonary bypass in-line blood gas sensor.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass in-line blood gas sensor... Cardiopulmonary bypass in-line blood gas sensor. (a) Identification. A cardiopulmonary bypass in-line blood gas sensor is a transducer that measures the level of gases in the blood. (b) Classification. Class II...

21 CFR 870.4410 - Cardiopulmonary bypass in-line blood gas sensor.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass in-line blood gas sensor... Cardiopulmonary bypass in-line blood gas sensor. (a) Identification. A cardiopulmonary bypass in-line blood gas sensor is a transducer that measures the level of gases in the blood. (b) Classification. Class II...

21 CFR 870.4410 - Cardiopulmonary bypass in-line blood gas sensor.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass in-line blood gas sensor... Cardiopulmonary bypass in-line blood gas sensor. (a) Identification. A cardiopulmonary bypass in-line blood gas sensor is a transducer that measures the level of gases in the blood. (b) Classification. Class II...

21 CFR 870.4410 - Cardiopulmonary bypass in-line blood gas sensor.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass in-line blood gas sensor... Cardiopulmonary bypass in-line blood gas sensor. (a) Identification. A cardiopulmonary bypass in-line blood gas sensor is a transducer that measures the level of gases in the blood. (b) Classification. Class II...

30 CFR 57.19018 - Overtravel by-pass switches.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Overtravel by-pass switches. 57.19018 Section... Hoisting Hoists § 57.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the switch shall function so as to allow the conveyance to be moved through the overtravel position when the...

30 CFR 56.19018 - Overtravel by-pass switches.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Overtravel by-pass switches. 56.19018 Section... Hoisting Hoists § 56.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the switch shall function so as to allow the conveyance to be moved through the overtravel position when the...

30 CFR 57.19018 - Overtravel by-pass switches.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Overtravel by-pass switches. 57.19018 Section... Hoisting Hoists § 57.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the switch shall function so as to allow the conveyance to be moved through the overtravel position when the...

30 CFR 56.19018 - Overtravel by-pass switches.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Overtravel by-pass switches. 56.19018 Section... Hoisting Hoists § 56.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the switch shall function so as to allow the conveyance to be moved through the overtravel position when the...

30 CFR 57.19018 - Overtravel by-pass switches.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Overtravel by-pass switches. 57.19018 Section... Hoisting Hoists § 57.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the switch shall function so as to allow the conveyance to be moved through the overtravel position when the...

30 CFR 56.19018 - Overtravel by-pass switches.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Overtravel by-pass switches. 56.19018 Section... Hoisting Hoists § 56.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the switch shall function so as to allow the conveyance to be moved through the overtravel position when the...

30 CFR 57.19018 - Overtravel by-pass switches.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Overtravel by-pass switches. 57.19018 Section... Hoisting Hoists § 57.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the switch shall function so as to allow the conveyance to be moved through the overtravel position when the...

30 CFR 57.19018 - Overtravel by-pass switches.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Overtravel by-pass switches. 57.19018 Section... Hoisting Hoists § 57.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the switch shall function so as to allow the conveyance to be moved through the overtravel position when the...

30 CFR 56.19018 - Overtravel by-pass switches.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Overtravel by-pass switches. 56.19018 Section... Hoisting Hoists § 56.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the switch shall function so as to allow the conveyance to be moved through the overtravel position when the...

30 CFR 56.19018 - Overtravel by-pass switches.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Overtravel by-pass switches. 56.19018 Section... Hoisting Hoists § 56.19018 Overtravel by-pass switches. When an overtravel by-pass switch is installed, the switch shall function so as to allow the conveyance to be moved through the overtravel position when the...

21 CFR 870.4220 - Cardiopulmonary bypass heart-lung machine console.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass heart-lung machine console... Cardiopulmonary bypass heart-lung machine console. (a) Identification. A cardiopulmonary bypass heart-lung machine... heart-lung machine. The console is designed to interface with the basic units used in a gas exchange...

21 CFR 870.4220 - Cardiopulmonary bypass heart-lung machine console.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass heart-lung machine console... Cardiopulmonary bypass heart-lung machine console. (a) Identification. A cardiopulmonary bypass heart-lung machine... heart-lung machine. The console is designed to interface with the basic units used in a gas exchange...

21 CFR 870.4220 - Cardiopulmonary bypass heart-lung machine console.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass heart-lung machine console... Cardiopulmonary bypass heart-lung machine console. (a) Identification. A cardiopulmonary bypass heart-lung machine... heart-lung machine. The console is designed to interface with the basic units used in a gas exchange...

21 CFR 870.4220 - Cardiopulmonary bypass heart-lung machine console.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass heart-lung machine console... Cardiopulmonary bypass heart-lung machine console. (a) Identification. A cardiopulmonary bypass heart-lung machine... heart-lung machine. The console is designed to interface with the basic units used in a gas exchange...

Capacity analysis of a bypass of roundabouts

NASA Astrophysics Data System (ADS)

Sedlačik, Ivan; Slabý, Petr

2017-09-01

The capacity of the roads network mainly depends on the capacity of its nodal points - intersections. A connecting branch or a bypass is a lane or lanes inserted between two adjacent branches of a roundabout, providing redirection of vehicles, that would otherwise burden a circular lane. A bypass effect to the capacity of roundabouts, but also other types of level intersections, is undeniable. A connecting branch increases the total capacity of an intersection that takes a part of vehicles performing a manoeuver of the first right turn completely out of an intersection area. Redirecting vehicles reduces delay times at intersections and reduces queues at the entrance to an intersection. Bypasses improve the quality of transport. Limiting for the capacity of bypasses is the point of disconnection from the entrance into the roundabout and the connection point into the exit from the roundabout. Central parts of the bypasses have minimal effects on the capacity. The length of a bypass has to match with the maximum length of a queue of waiting vehicles at a given intensity level. The article deals with analysis of the bypass capacity at the roundabouts.

Long-Term Patency of Posterior Auricular Artery-Middle Cerebral Artery Bypass for Adult-Onset Moyamoya Disease: Case Report and Review of Literature.

PubMed

Torazawa, Seiei; Hasegawa, Hirotaka; Kin, Taichi; Sato, Hiroaki; Sora, Shigeo

2017-12-01

Direct extracranial-intracranial (EC-IC) bypass is one of the fundamental techniques to prevent recurrent stroke in patients with adult-onset ischemic moyamoya disease. When the standard superficial temporal artery (STA) cannot be used for a graft, the posterior auricular artery (PAA) can be a potential surrogate graft. In this article, the authors reported a 34-year-old female patient suffering from ischemic moyamoya disease. To widely revascularize the anterior half of the hemisphere, direct double EC-IC bypass was considered beneficial; however, she had only a single-branched STA but had a prominent branch of the PAA. After discussion, a direct double surgical revascularization was successfully performed using a combination of the STA-middle cerebral artery (MCA) and the PAA-MCA bypass. The authors herein reported the detailed surgical technique of the PAA-MCA bypass with an informative video of the actual procedure. To clearly define the feasibility of PAA-MCA bypass, the authors also conducted a literature review, yielding 3 previous articles describing the bypass. In conclusion, the PAA becomes a potential donor for EC-IC bypass as long as its diameter is approximately 1.0 mm. Even though the PAA-MCA bypass is not primarily considered in the initial revascularization, it can be useful as a combination bypass with other grafts or as a rescue for recurrent ischemia. Copyright © 2017 Elsevier Inc. All rights reserved.

4D flow MRI assessment of extracranial-intracranial bypass: qualitative and quantitative evaluation of the hemodynamics.

PubMed

Sekine, Tetsuro; Takagi, Ryo; Amano, Yasuo; Murai, Yasuo; Orita, Erika; Matsumura, Yoshio; Kumita, Shin-Ichiro

2016-03-01

Our aim was to assess the feasibility of using time-resolved 3D phase-contrast (4D flow) MRI to characterize extracranial-intracranial (EC-IC) bypass. We enrolled 32 patients who underwent EC-IC bypass (15 men, 17 women; mean age 66.4 years). In all, 16 underwent radial artery graft (RAG) bypass and 16 underwent superficial temporal artery (STA) bypass. 4D flow MRI, time-of-flight (TOF) magnetic resonance angiography (MRA), and computed tomography angiography (CTA) were performed. Bypass patency, flow direction, and blood flow volume (BFV) of each artery were determined by 4D flow MRI. Arterial diameters were measured by TOF-MRA and CTA. We compared RAG and STA bypasses by evaluating the flow direction and BFV of each artery. We evaluated the correlation between arterial diameters (measured by CTA or MRA) and the BFV and the detectability of flow direction (measured by 4D flow MRI) of each artery. 4D flow MRI confirmed the patency of each bypass artery. Flow direction of the M1 segment of the middle cerebral artery and BFV in the bypass artery differed between RAG and STA groups (p < 0.01). BFV in the bypass slightly correlated with the diameters on CTA (p < 0.05, R (2) = 0.287). Of the 29 arteries in the circle of Willis, nine were not depicted on 4D flow MRI. Cutoff values for arterial diameters on CTA and TOF-MRA for detecting the artery on 4D flow MRI were 2.4 and 1.8 mm, respectively. 4D flow MRI provided unique information for characterizing EC-IC bypasses, although this detectability is limited when addressing small arteries with slow flow.

Off-pump coronary artery bypass surgery in selected patients is superior to the conventional approach for patients with severely depressed left ventricular function

PubMed Central

Caputti, Guido Marco; Palma, José Honório; Gaia, Diego Felipe; Buffolo, Enio

2011-01-01

OBJECTIVES: Patients with coronary artery disease and left ventricular dysfunction have high mortality when kept in clinical treatment. Coronary artery bypass grafting can improve survival and the quality of life. Recently, revascularization without cardiopulmonary bypass has been presented as a viable alternative. The aim of this study is to compare patients with left ventricular ejection fractions of less than 20% who underwent coronary artery bypass graft with or without cardiopulmonary bypass. METHODS: From January 2001 to December 2005, 217 nonrandomized, consecutive, and nonselected patients with an ejection fraction less than or equal to 20% underwent coronary artery bypass graft surgery with (112) or without (off-pump) (105) the use of cardiopulmonary bypass. We studied demographic, operative, and postoperative data. RESULTS: There were no demographic differences between groups. The outcome variables showed similar graft numbers in both groups. Mortality was 12.5% in the cardiopulmonary bypass group and 3.8% in the off-pump group. Postoperative complications were statistically different (cardiopulmonary bypass versus off-pump): total length of hospital stay (days)—11.3 vs. 7.2, length of ICU stay (days)—3.7 vs. 2.1, pulmonary complications—10.7% vs. 2.8%, intubation time (hours)—22 vs. 10, postoperative bleeding (mL)—654 vs. 440, acute renal failure—8.9% vs. 1.9% and left-ventricle ejection fraction before discharge—22% vs. 29%. CONCLUSION: Coronary artery bypass grafting without cardiopulmonary bypass in selected patients with severe left ventricular dysfunction is valid and safe and promotes less mortality and morbidity compared with conventional operations. PMID:22189729

Angiographic flow grading and graft arrangement of arterial conduits.

PubMed

Nakajima, Hiroyuki; Kobayashi, Junjiro; Tagusari, Osamu; Niwaya, Kazuo; Funatsu, Toshihiro; Kawamura, Atsushi; Yagihara, Toshikatsu; Kitamura, Soichiro

2006-11-01

We sought to delineate the effects of competitive and reverse flow on the intermediate-term patency of arterial conduits and examined graft arrangements for maximizing antegrade bypass flow. The angiograms of 2083 bypass grafts in 570 patients who underwent off-pump total arterial revascularization without aortic manipulation since December 2000 were reviewed. The blood flow in the bypass grafts were graded A (antegrade), B (competitive), C (reverse), or O (occlusion). The mean number of distal anastomoses was 3.65 +/- 0.94 per patient. In the early angiography 91.3% (1901/2083) of the bypasses were grade A. Thirty (1.4%) bypasses were grade O, whereas 2.9% (61/2083) were grade B, and 4.4%(91/2083) were grade C. In the multivariate analysis the end-to-side anastomosis (P < .0001), 4 or more distal anastomoses of the conduit (P = .01), native coronary stenosis of less than 75% (P < .0001), and target branch location of the right coronary artery territory (P < .0001) and left circumflex artery territory (P = .02) significantly correlated with grade non-A. The patency rate in the late angiography of the bypasses graded B or C in the early angiography was 7 (28.0%) of 25, whereas that of the bypasses graded A was 164 (89.1%) of 184 (P < .0001). The actuarial graft patency rate of the bypasses graded A was 72.3% at 3 years and was significantly higher than that of the bypasses graded B or C (28.6% at 3 years after surgical intervention, P < .0001). The sufficient antegrade bypass flow had a favorable effect on the graft patency of arterial conduits. The graft arrangement should be adjusted for each patient so as to maximize the antegrade bypass flow and to confirm the advantage of arterial grafts.

Long-term patency of superficial temporal artery to middle cerebral artery bypass for cerebral atherosclerotic disease: factors determining the bypass patent.

PubMed

Matano, Fumihiro; Murai, Yasuo; Tateyama, Kojiro; Tamaki, Tomonori; Mizunari, Takayuki; Matsukawa, Hideoshi; Teramoto, Akira; Morita, Akio

2016-10-01

Long-term patency of superficial temporal artery to middle cerebral artery (STA-MCA) bypass surgery for atherosclerotic disease and associated risk factors for loss of patency have rarely been discussed. We retrospectively analyzed long-term patency following STA-MCA bypass and evaluated various demographic and clinical factors to identify the ones predictive of postsurgical loss of patency using records of 84 revascularization procedures (58 patients, 45 males; mean age at surgery 63.6 years, range 31-78 years). Bypass patency was diagnosed based on magnetic resonance angiography or three-dimensional computed tomography. The mean follow-up period was 24.7 months (range 6-63 months). Decreased bypass patency was observed in 4 of 58 patients (6.9 %) who collectively underwent 6 bypasses (7.1 %) of 84. All cases of decreased bypass patency were first detected within 6 months of surgery. Bypass patency was not correlated with age, sex, number of anastomoses, postoperative cerebral infarction, or control of postoperative diabetes mellitus. We found a significant association of bypass patency with hyperperfusion (p = 0.01) and postoperative smoking (p = 0.0036). Furthermore, we found a significant association of hyperperfusion with STA diameter (p < 0.0001), location of anastomosis (p = 0.075), and preoperative cerebral blood flow (p = 0.0399). In our retrospective study, hyperperfusion and smoking after surgery may be risk factors for decreased bypass patency in cerebral atherosclerotic disease patients. Careful monitoring of patency to prevent hyperperfusion and cessation of smoking are recommended, particularly within 6 months of the surgery.

Esophageal bypass operation prior to definitive chemoradiotherapy in advanced esophageal cancer with tracheobronchial invasion.

PubMed

Hihara, Jun; Hamai, Yoichi; Emi, Manabu; Aoki, Yoshiro; Taomoto, Junya; Miyata, Yoshihiro; Okada, Morihito

2014-01-01

In T4 esophageal cancer with tracheobronchial invasion, an esophagorespiratory fistula (ERF) often occurs during or after chemoradiotherapy. We have performed esophageal bypass operations prior to definitive chemoradiotherapy for these patients to increase the chemoradiotherapy completion rate by minimizing the potential effect of an ERF. The aim of this study was to examine the clinical outcome of esophageal bypass surgery prior to chemoradiotherapy. Between 1997 and 2010, 17 patients underwent esophageal bypass surgery followed by definitive chemoradiotherapy for esophageal cancer with tracheobronchial invasion (bypass group). Ten patients in the same circumstances were treated with chemoradiotherapy alone (control group). Overall survival, the clinical effect of chemoradiotherapy, the ERF incidence rate, and the safety of esophageal bypass surgery were assessed. The overall response rate to chemoradiotherapy was 64.7% in the bypass group and 90.0% in the control group. Except for 2 patients with ERF at initial diagnosis, 4 (26.7%) of the 15 patients developed ERF in the bypass group, and 3 (30.0%) of the 10 patients developed ERF in the control group during or after chemoradiotherapy. The 2-year and 3-year overall survival rates were 17.6% and 17.6% in the bypass group and 20.0% and 0% in the control group, respectively (p = 0.924); long-term survival of more than 3 years was seen only in the bypass group. Esophageal bypass surgery prior to definitive chemoradiotherapy could be performed safely, and this strategy contributed to long-term survival in the patients who achieved a good response to chemoradiotherapy but developed an ERF. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Quality of clinical care and bypassing of primary health centers in India.

PubMed

Rao, Krishna D; Sheffel, Ashley

2018-06-01

In many low and middle-income countries patients often bypass the nearest government health center offering free or subsidized services and seek more expensive care elsewhere. This study examines the role of quality of care, in particular clinician competence and structural quality of the health center, on bypassing behavior. Data for this study comes from a survey of 136 primary health centers (PHCs) and 3517 individuals living in the PHC's immediate vicinity in rural Chhattisgarh, India. Overall, the majority (67%) of patients bypassed the local PHC when seeking treatment. Bypassing decreased as provider competence increased, up to a point, after which, improvements in competency did not reduce bypassing. The clinical competence of the health care provider had a greater effect on reducing bypassing compared to PHC structural quality such as the building condition and drug stock-outs. However, the regular presence of clinical providers in the PHC was associated with lower bypassing. Patients that visited the local PHC spent half as much out-of-pocket as those that were treated at private clinics. Poor patients were less likely to bypass the local PHC compared to non-poor patients. These findings suggest that improving structural quality is not sufficient to reduce bypassing of PHCs. While better provider competency can substantially reduce bypassing, beyond a threshold competency level there is little effect. Efforts to strengthen facility-based primary care services need to go beyond simply focusing on improving infrastructure or quality of clinical care. There is a need to rethink how PHCs can be made more relevant to the health care needs of the communities they serve. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bypass system modification at Bonneville Dam on the Columbia River improved the survival of juvenile salmon

USGS Publications Warehouse

Ferguson, J.W.; Sandford, B.P.; Reagan, R.E.; Gilbreath, L.G.; Meyer, E.B.; Ledgerwood, R.D.; Adams, N.S.

2007-01-01

From 1987 to 1992, we evaluated a fish bypass system at Bonneville Dam Powerhouse 2 on the Columbia River. The survival of subyearling Chinook salmon Oncorhynchus tshawytscha released into the system ranged from 0.774 to 0.911 and was significantly lower than the survival of test fish released into turbines and the area immediately below the powerhouse where bypass system flow reentered the river. Yearling and subyearling Chinook salmon and yearling coho salmon O. kisutch released into the bypass system were injured or descaled. Also, levels of blood plasma cortisol and lactate were significantly higher in yearling and subyearling Chinook salmon that passed through the bypass system than in fish released directly into a net located over the bypass exit. This original system was then extensively modified using updated design criteria, and the site where juvenile fish reentered the river was relocated 2.8 km further downstream to reduce predation on bypassed fish by northern pikeminnow Ptychocheilus oregonensis. Based on studies conducted from 1999 to 2001, the new bypass system resulted in high fish survival, virtually no injuries to fish, fish passage times that were generally similar to water travel times, and mild stress responses from which fish recovered quickly. The mean estimated survival of subyearling Chinook salmon passing through the new bypass system was 0.946 in 2001, which was an usually low-flow year. Survival, physical condition, passage timing, and blood physiological indicators of stress were all useful metrics for assessing the performance of both bypass systems and are discussed. The engineering and hydraulic criteria used to design the new bypass system that resulted in improved fish passage conditions are described.

Direct Bypass Versus Indirect Bypass in Adult Moyamoya Angiopathy with Symptoms or Hemodynamic Instability: A Meta-analysis of Comparative Studies.

PubMed

Kim, Hoon; Jang, Dong-Kyu; Han, Young-Min; Sung, Jae Hoon; Park, Ik Seong; Lee, Kwan-Sung; Yang, Ji-Ho; Huh, Pil Woo; Park, Young Sup; Kim, Dal-Soo; Han, Kyung-Do

2016-10-01

It remains controversial which bypass methods are optimal for treating adult moyamoya angiopathy patients. This study aimed to analyze the literature about whether different bypass methods affect differently outcome results of adult moyamoya patients with symptoms or hemodynamic instability. A systematic search of the PubMed, Embase, and Cochrane Central databases was performed for articles published between 1990 and 2015. Comparative studies about the effect of direct or combined bypass (direct bypass group) and indirect bypass (indirect bypass group) in patients with moyamoya angiopathy at 18 years of age or older were selected. For stroke incidence at the end of the follow-up period, the degree of angiographic revascularization, hemodynamic improvement, and perioperative complication rates within 30 days, pooled relative risks were calculated between the 2 groups with a 95% confidence interval. A total of 8 articles (including 536 patients and 732 treated hemispheres) were included in the meta-analysis. There were no significant differences between the 2 groups when we compared the overall stroke rate, the hemodynamic improvement rate, or the perioperative complication rate at the end of the follow-up period. The direct bypass group, however, had a lower risk than the indirect bypass group for obtaining a poor angiographic revascularization rate (risk ratio, 0.35; 95% confidence interval, 0.15-0.84; P = 0.02). The current meta-analysis suggests that the direct or combined bypass surgical method is better for angiographic revascularization in adult moyamoya patients with symptoms or hemodynamic instability. Future studies may be necessary to confirm these findings. Copyright © 2016 Elsevier Inc. All rights reserved.

Assessing the impact of total extracorporeal circulation on hemodynamics in an ovine fetal model.

PubMed

Xiao, Fei; Zhuang, Jian; Zhou, Cheng-Bin; Chen, Ji-Mei; Cen, Jian-Zheng; Xu, Gang; Wen, Shu-Sheng

2017-09-01

The present study aimed to evaluate the impact of total extracorporeal circulation on hemodynamics and placental function in an ovine fetal model. Mid-term ovine fetuses (n=6) underwent extracorporeal circulation (30 min), cardioplegic arrest (20 min) and monitoring (120 min). The ascending aorta and umbilical cords of the fetuses were occluded during the bypass and an extracorporeal membrane oxygenator was used as the oxygen source. Biventricular intracardiac pressures, echocardiographic data, blood gas levels and placental function variables were recorded, and statistical analysis was performed using the repeated-measure analysis of variance test. The data indicated that fetal heart rate and blood pressure at 30, 60, 90 and 120 min following the bypass were stable relative to pre-arrest baseline (pre-bypass) values (P>0.05). However, end diastolic pressures in the ovine right ventricles post-bypass were significantly increased at 30, 60, 90 and 120 min relative to pre-bypass pressures (P<0.05). The pulsatility index also increased at 30 min post-bypass relative to the pre-bypass score (0.91±0.06 vs. 0.61±0.14; P=0.007). The mean resistivity index at all time points post-bypass was consistent with the pre-bypass score (P>0.05), while the mean Tei index values for the left and right ventricles post-bypass were significantly higher at all time points relative to pre-bypass values (P<0.05). The pre-bypass fetal blood pH, SaO 2 , base excess and lactate values were maintained during arrest (P>0.05). Fetal hemodynamics and placental function additionally remained stable for up to 2 h upon reperfusion following total extracorporeal circulation and cardioplegic arrest. Collectively these data suggest that the reproducible ovine fetal model may be useful in the evaluation of fetal cardiac surgery.

Feasibility and safety of minimized cardiopulmonary bypass in major aortic surgery

PubMed Central

Momin, Aziz U.; Sharabiani, Mansour T. A.; Kidher, Emadin; Najefi, Ali; Mulholland, John W.; Reeves, Barnaby C.; Angelini, Gianni D.; Anderson, Jon R.

2013-01-01

OBJECTIVES Conventional cardiopulmonary bypass causes haemodilution and is a trigger of systemic inflammatory reactions, coagulopathy and organ failure. Miniaturized cardiopulmonary bypass has been proposed as a way to reduce these deleterious effects of conventional cardiopulmonary bypass and to promote a more physiological state. The use of miniaturized cardiopulmonary bypass has been reported in low-risk patients undergoing valve and coronary artery bypass graft (CABG) surgery. However, little is known about its application in major aortic surgery. METHODS From February 2007 to September 2010, 49 patients underwent major aortic surgery using the Hammersmith miniaturized cardiopulmonary bypass (ECCO, Sorin). Data were extracted from medical records to characterize preoperative comorbidities (EuroSCORE), perioperative complications and the use of blood products. The same data were collected and described for 328 consecutive patients having similar surgery with conventional cardiopulmonary bypass at the Bristol Heart Institute, our twinned centre, during the same period. RESULTS The miniaturized cardiopulmonary bypass group had a median EuroSCORE of 8 [inter-quartile range (IQR): 5–11], 13% had preoperative renal dysfunction and 20% of operations were classified as emergency or salvage. Thirty-day mortalities were 6.4; and 69, 67 and 74% had ≥1 unit of red cells, fresh frozen plasma (FFP) and platelets transfused, respectively. Eight percent of patients experienced a renal complication, and 8% a neurological complication. The conventional cardiopulmonary bypass group was similar, with a EuroSCORE of 8 (IQR: 6–10); 30-day mortalities were 9.4; and 68, 62 and 74% had ≥1 unit of red cells, FFP and platelets transfused, respectively. The proportions experiencing renal and neurological complications were 14 and 5%. CONCLUSIONS Our experience suggests that miniaturized cardiopulmonary bypass is safe and feasible for use in major aortic cardiac surgery. A randomized trial is needed to evaluate miniaturized cardiopulmonary bypass formally. PMID:23814138

Bypass of a 5',8-cyclopurine-2'-deoxynucleoside by DNA polymerase β during DNA replication and base excision repair leads to nucleotide misinsertions and DNA strand breaks.

PubMed

Jiang, Zhongliang; Xu, Meng; Lai, Yanhao; Laverde, Eduardo E; Terzidis, Michael A; Masi, Annalisa; Chatgilialoglu, Chryssostomos; Liu, Yuan

2015-09-01

5',8-Cyclopurine-2'-deoxynucleosides including 5',8-cyclo-dA (cdA) and 5',8-cyclo-dG (cdG) are induced by hydroxyl radicals resulting from oxidative stress such as ionizing radiation. 5',8-cyclopurine-2'-deoxynucleoside lesions are repaired by nucleotide excision repair with low efficiency, thereby leading to their accumulation in the human genome and lesion bypass by DNA polymerases during DNA replication and base excision repair (BER). In this study, for the first time, we discovered that DNA polymerase β (pol β) efficiently bypassed a 5'R-cdA, but inefficiently bypassed a 5'S-cdA during DNA replication and BER. We found that cell extracts from pol β wild-type mouse embryonic fibroblasts exhibited significant DNA synthesis activity in bypassing a cdA lesion located in replication and BER intermediates. However, pol β knock-out cell extracts exhibited little DNA synthesis to bypass the lesion. This indicates that pol β plays an important role in bypassing a cdA lesion during DNA replication and BER. Furthermore, we demonstrated that pol β inserted both a correct and incorrect nucleotide to bypass a cdA at a low concentration. Nucleotide misinsertion was significantly stimulated by a high concentration of pol β, indicating a mutagenic effect induced by pol β lesion bypass synthesis of a 5',8-cyclopurine-2'-deoxynucleoside. Moreover, we found that bypass of a 5'S-cdA by pol β generated an intermediate that failed to be extended by pol β, resulting in accumulation of single-strand DNA breaks. Our study provides the first evidence that pol β plays an important role in bypassing a 5',8-cyclo-dA during DNA replication and repair, as well as new insight into mutagenic effects and genome instability resulting from pol β bypassing of a cdA lesion. Copyright © 2015 Elsevier B.V. All rights reserved.

Efficacy of duplex ultrasound surveillance after infrainguinal vein bypass may be enhanced by identification of characteristics predictive of graft stenosis development.

PubMed

Tinder, Chelsey N; Chavanpun, Joe P; Bandyk, Dennis F; Armstrong, Paul A; Back, Martin R; Johnson, Brad L; Shames, Murray L

2008-09-01

Controversy regarding the efficacy of duplex ultrasound surveillance after infrainguinal vein bypass led to an analysis of patient and bypass graft characteristics predictive for development of graft stenosis and a decision of secondary intervention. Retrospective analysis of a contemporary, consecutive series of 353 clinically successful infrainguinal vein bypasses performed in 329 patients for critical (n = 284; 80%) or noncritical (n = 69; 20%) limb ischemia enrolled in a surveillance program to identify and repair duplex-detected graft stenosis. Variables correlated with graft stenosis and bypass repair included: procedure indication, conduit type (saphenous vs nonsaphenous vein; reversed vs nonreversed orientation), prior bypass graft failure, postoperative ankle-brachial index (ABI) < 0.85, and interpretation of the first duplex surveillance study as "normal" or "abnormal" based on peak systolic velocity (PSV) and velocity ratio (Vr) criteria. Overall, 126 (36%) of the 353 infrainguinal bypasses had 174 secondary interventions (endovascular, 100; surgery, 74) based on duplex surveillance; resulting in 3-year Kaplan-Meier primary (46%), assisted-primary (80%), and secondary (81%) patency rates. Characteristics predictive of duplex-detected stenosis leading to intervention (PSV: 443 +/- 94 cm/s; Vr: 8.6 +/- 9) were: "abnormal" initial duplex testing indicating moderate (PSV: 180-300 cm/s, Vr: 2-3.5) stenosis (P < .0001), non-single segment saphenous vein conduit (P < .01), warfarin drug therapy (P < .01), and redo bypass grafting (P < .001). Procedure indication, postoperative ABI level, statin drug therapy, and vein conduit orientation were not predictive of graft revision. The natural history of 141 (40%) bypasses with an abnormal first duplex scan differed from "normal" grafts by more frequent (51% vs 24%, P < .001) and earlier (7 months vs 11 months) graft revision for severe stenosis and a lower 3-year assisted primary patency (68% vs 87%; P < .001). In 52 (15%) limbs, the bypass graft failed and 20 (6%) limbs required amputation. The efficacy of duplex surveillance after infrainguinal vein bypass may be enhanced by modifying testing protocols, eg, rigorous surveillance for "higher risk" bypasses, based on the initial duplex scan results and other characteristics (warfarin therapy, non- single segment saphenous vein conduit, redo bypass) predictive for stenosis development.

Off-pump versus on-pump coronary artery bypass surgery in patients with actively treated diabetes and multivessel coronary disease.

PubMed

Benedetto, Umberto; Caputo, Massimo; Vohra, Hunaid; Davies, Alan; Hillier, James; Bryan, Alan; Angelini, Gianni D

2016-11-01

We conducted a single-center analysis on short-term outcomes and long-term survival in actively treated diabetic patients undergoing off-pump coronary artery bypass versus on-pump coronary artery bypass surgery. The final population consisted of 2450 patients with actively treated diabetes (mean age, 66 ± 9 years; female/male 545/1905, 22%). Of those, 1493 subjects were orally treated and 1011 subjects were taking insulin. Off-pump coronary artery bypass and on-pump coronary artery bypass were performed in 1253 and 1197 patients, respectively. Propensity score matching was used to compare the 2 matched groups. When compared with on-pump coronary artery bypass, off-pump coronary artery bypass was associated with a significant risk reduction for postoperative cerebrovascular accident (odds ratio, 0.49; 95% confidence interval [CI], 0.25-0.99; P = .04), need for postoperative intra-aortic balloon pump (odds ratio, 0.48; 95% CI, 0.30-0.77; P = .002), and reexploration for bleeding (odds ratio, 0.55; 95% CI, 0.33-0.94; P = .02). Off-pump coronary artery bypass did not significantly affect early (hazard ratio [HR], 1.32; 95% CI, 0.73-2.40; P = .36) and late (HR, 1.08; 95% CI, 0.92-1.28; P = .32) mortality. However, off-pump coronary artery bypass with incomplete revascularization was associated with reduced survival when compared with off-pump coronary artery bypass with complete revascularization (HR, 1.82; 95% CI, 1.34-2.46; P = .0002) and on-pump coronary artery bypass with complete revascularization (HR, 1.83; 95% CI, 1.36-2.47; P < .0001). Off-pump coronary artery bypass is a safe and feasible option for diabetic patients with multivessel disease, reduces the incidence of early complications including postoperative cerebrovascular events, and provides excellent long-term survival similar to on-pump coronary artery bypass surgery in case of complete revascularization. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Noninvasive, near infrared spectroscopic-measured muscle pH and PO2 indicate tissue perfusion for cardiac surgical patients undergoing cardiopulmonary bypass

NASA Technical Reports Server (NTRS)

Soller, Babs R.; Idwasi, Patrick O.; Balaguer, Jorge; Levin, Steven; Simsir, Sinan A.; Vander Salm, Thomas J.; Collette, Helen; Heard, Stephen O.

2003-01-01

OBJECTIVE: To determine whether near infrared spectroscopic measurement of tissue pH and Po2 has sufficient accuracy to assess variation in tissue perfusion resulting from changes in blood pressure and metabolic demand during cardiopulmonary bypass. DESIGN: Prospective clinical study. SETTING: Academic medical center. SUBJECTS: Eighteen elective cardiac surgical patients. INTERVENTION: Cardiac surgery under cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: A near infrared spectroscopic fiber optic probe was placed over the hypothenar eminence. Reference Po2 and pH sensors were inserted in the abductor digiti minimi (V). Data were collected every 30 secs during surgery and for 6 hrs following cardiopulmonary bypass. Calibration equations developed from one third of the data were used with the remaining data to investigate sensitivity of the near infrared spectroscopic measurement to physiologic changes resulting from cardiopulmonary bypass. Near infrared spectroscopic and reference pH and Po2 measurements were compared for each subject using standard error of prediction. Near infrared spectroscopic pH and Po2 at baseline were compared with values during cardiopulmonary bypass just before rewarming commenced (hypotensive, hypothermic), after rewarming (hypotensive, normothermic) just before discontinuation of cardiopulmonary bypass, and at 6 hrs following cardiopulmonary bypass (normotensive, normothermic) using mixed-model analysis of variance. Near infrared spectroscopic pH and Po2 were well correlated with the invasive measurement of pH (R2 =.84) and Po2 (R 2 =.66) with an average standard error of prediction of 0.022 +/- 0.008 pH units and 6 +/- 3 mm Hg, respectively. The average difference between the invasive and near infrared spectroscopic measurement was near zero for both the pH and Po2 measurements. Near infrared spectroscopic Po2 significantly decreased 50% on initiation of cardiopulmonary bypass and remained depressed throughout the bypass and monitored intensive care period. Near infrared spectroscopic pH decreased significantly during cardiopulmonary bypass, decreased significantly during rewarming, and remained depressed 6 hrs after cardiopulmonary bypass. Diabetic patients responded differently than nondiabetic subjects to cardiopulmonary bypass, with lower muscle pH values (p =.02). CONCLUSIONS: Near infrared spectroscopic-measured muscle pH and Po2 are sensitive to changes in tissue perfusion during cardiopulmonary bypass.

21 CFR 870.4330 - Cardiopulmonary bypass on-line blood gas monitor.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass on-line blood gas monitor... Cardiopulmonary bypass on-line blood gas monitor. (a) Identification. A cardiopulmonary bypass on-line blood gas monitor is a device used in conjunction with a blood gas sensor to measure the level of gases in the blood...

21 CFR 870.4330 - Cardiopulmonary bypass on-line blood gas monitor.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass on-line blood gas monitor... Cardiopulmonary bypass on-line blood gas monitor. (a) Identification. A cardiopulmonary bypass on-line blood gas monitor is a device used in conjunction with a blood gas sensor to measure the level of gases in the blood...

21 CFR 870.4330 - Cardiopulmonary bypass on-line blood gas monitor.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass on-line blood gas monitor... Cardiopulmonary bypass on-line blood gas monitor. (a) Identification. A cardiopulmonary bypass on-line blood gas monitor is a device used in conjunction with a blood gas sensor to measure the level of gases in the blood...

21 CFR 870.4330 - Cardiopulmonary bypass on-line blood gas monitor.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Cardiopulmonary bypass on-line blood gas monitor. (a) Identification. A cardiopulmonary bypass on-line blood gas monitor is a device used in conjunction with a blood gas sensor to measure the level of gases in the blood... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass on-line blood gas monitor...

21 CFR 870.4330 - Cardiopulmonary bypass on-line blood gas monitor.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Cardiopulmonary bypass on-line blood gas monitor. (a) Identification. A cardiopulmonary bypass on-line blood gas monitor is a device used in conjunction with a blood gas sensor to measure the level of gases in the blood... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass on-line blood gas monitor...

Low-Voltage Bypass Device

NASA Technical Reports Server (NTRS)

Wilson, J. P.

1994-01-01

Improved bypass device provides low-resistance current shunt around low-voltage power cell when cell fails in open-circuit condition during operation. In comparison with older bypass devices for same application, this one weighs less, generates less heat, and has lower voltage drop (less resistance). Bypass device connected in parallel with power cell. Draws very little current during normal operation of cell.

Airway bypass treatment of severe homogeneous emphysema: taking advantage of collateral ventilation.

PubMed

Choong, Cliff K; Cardoso, Paulo F G; Sybrecht, Gerhard W; Cooper, Joel D

2009-05-01

Airway bypass is being investigated as a new form of minimally invasive therapy for the treatment of homogeneous emphysema. It is a bronchoscopic catheter-based procedure that creates transbronchial extra-anatomic passages at the bronchial segmental level. The passages are expanded, supported with the expectation that the patency is maintained by paclitaxel drug-eluting airway bypass stents. The concept of airway bypass has been demonstrated in two separate experimental studies. These studies have shown that airway bypass takes advantage of collateral ventilation present in homogeneous emphysema to allow trapped gas to escape and reduce hyperinflation. It improves lung mechanics, expiratory flow, and volume. Airway bypass stent placements have been shown to be feasible and safe in both animal and human studies. Paclitaxel-eluting airway bypass stents were found to prolong stent patency and were adopted for clinical studies. A study evaluating the early results of the clinical application of airway bypass with paclitaxel-eluting stents found that airway bypass procedures reduced hyperinflation and improved pulmonary function and dyspnea in selected subjects who have severe emphysema. The duration of benefit appeared to correlate with the degree of pretreatment hyperinflation. These preliminary clinical results supported further evaluation of the procedure and led to the EASE Trial. The EASE Trial is a prospective, multicenter, randomized, double-blind, sham-controlled study. The trial aims to evaluate the safety and effectiveness of the airway bypass to improve pulmonary function and reduce dyspnea in homogeneous emphysema subjects who have severe hyperinflation. The trial is presently ongoing worldwide, though enrollment was completed.

Gastric bypass reduces fat intake and preference

PubMed Central

Bueter, Marco; Theis, Nadine; Werling, Malin; Ashrafian, Hutan; Löwenstein, Christian; Athanasiou, Thanos; Bloom, Stephen R.; Spector, Alan C.; Olbers, Torsten; Lutz, Thomas A.

2011-01-01

Roux-en-Y gastric bypass is the most effective therapy for morbid obesity. This study investigated how gastric bypass affects intake of and preference for high-fat food in an experimental (rat) study and within a trial setting (human). Proportion of dietary fat in gastric bypass patients was significantly lower 6 yr after surgery compared with patients after vertical-banded gastroplasty (P = 0.046). Gastric bypass reduced total fat and caloric intake (P < 0.001) and increased standard low-fat chow consumption compared with sham controls (P < 0.001) in rats. Compared with sham-operated rats, gastric bypass rats displayed much lower preferences for Intralipid concentrations > 0.5% in an ascending concentration series (0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%) of two-bottle preference tests (P = 0.005). This effect was demonstrated 10 and 200 days after surgery. However, there was no difference in appetitive or consummatory behavior in the brief access test between the two groups (P = 0.71) using similar Intralipid concentrations (0.005% through 5%). Levels of glucagon-like peptide-1 (GLP-1) were increased after gastric bypass as expected. An oral gavage of 1 ml corn oil after saccharin ingestion in gastric bypass rats induced a conditioned taste aversion. These findings suggest that changes in fat preference may contribute to long-term maintained weight loss after gastric bypass. Postingestive effects of high-fat nutrients resulting in conditioned taste aversion may partially explain this observation; the role of GLP-1 in mediating postprandial responses after gastric bypass requires further investigation. PMID:21734019

Sulforaphane pretreatment prevents systemic inflammation and renal injury in response to cardiopulmonary bypass.

PubMed

Nguyen, Bao; Luong, Le; Naase, Hatam; Vives, Marc; Jakaj, Gentjan; Finch, Jonathan; Boyle, Joseph; Mulholland, John W; Kwak, Jong-hwan; Pyo, Suhkneung; de Luca, Amalia; Athanasiou, Thanos; Angelini, Gianni; Anderson, Jon; Haskard, Dorian O; Evans, Paul C

2014-08-01

Systemic inflammatory responses are a major cause of morbidity and mortality in patients undergoing cardiac surgery with cardiopulmonary bypass. However, the underlying molecular mechanisms for systemic inflammation in response to cardiopulmonary bypass are poorly understood. A porcine model was established to study the signaling pathways that promote systemic inflammation in response to cardiac surgery with cardiopulmonary bypass under well-controlled experimental conditions. The influence of sulforaphane, an anti-inflammatory compound derived from green vegetables, on inflammation and injury in response to cardiopulmonary bypass was also studied. Intracellular staining and flow cytometry were performed to measure phosphorylation of p38 mitogen-activated protein kinase and the transcription factor nuclear factor-κB in granulocytes and mononuclear cells. Surgery with cardiopulmonary bypass for 1 to 2 hours enhanced phosphorylation of p38 (2.5-fold) and nuclear factor-κB (1.6-fold) in circulating mononuclear cells. Cardiopulmonary bypass also modified granulocytes by activating nuclear factor-κB (1.6-fold), whereas p38 was not altered. Histologic analyses revealed that cardiopulmonary bypass promoted acute tubular necrosis. Pretreatment of animals with sulforaphane reduced p38 (90% reduction) and nuclear factor-κB (50% reduction) phosphorylation in leukocytes and protected kidneys from injury. Systemic inflammatory responses after cardiopulmonary bypass were associated with activation of p38 and nuclear factor-κB pathways in circulating leukocytes. Inflammatory responses to cardiopulmonary bypass can be reduced by sulforaphane, which reduced leukocyte activation and protected against renal injury. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

Gastric bypass reduces fat intake and preference.

PubMed

le Roux, Carel W; Bueter, Marco; Theis, Nadine; Werling, Malin; Ashrafian, Hutan; Löwenstein, Christian; Athanasiou, Thanos; Bloom, Stephen R; Spector, Alan C; Olbers, Torsten; Lutz, Thomas A

2011-10-01

Roux-en-Y gastric bypass is the most effective therapy for morbid obesity. This study investigated how gastric bypass affects intake of and preference for high-fat food in an experimental (rat) study and within a trial setting (human). Proportion of dietary fat in gastric bypass patients was significantly lower 6 yr after surgery compared with patients after vertical-banded gastroplasty (P = 0.046). Gastric bypass reduced total fat and caloric intake (P < 0.001) and increased standard low-fat chow consumption compared with sham controls (P < 0.001) in rats. Compared with sham-operated rats, gastric bypass rats displayed much lower preferences for Intralipid concentrations > 0.5% in an ascending concentration series (0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%) of two-bottle preference tests (P = 0.005). This effect was demonstrated 10 and 200 days after surgery. However, there was no difference in appetitive or consummatory behavior in the brief access test between the two groups (P = 0.71) using similar Intralipid concentrations (0.005% through 5%). Levels of glucagon-like peptide-1 (GLP-1) were increased after gastric bypass as expected. An oral gavage of 1 ml corn oil after saccharin ingestion in gastric bypass rats induced a conditioned taste aversion. These findings suggest that changes in fat preference may contribute to long-term maintained weight loss after gastric bypass. Postingestive effects of high-fat nutrients resulting in conditioned taste aversion may partially explain this observation; the role of GLP-1 in mediating postprandial responses after gastric bypass requires further investigation.

Resurrection of the in situ saphenous vein bypass. 1000 cases later.

PubMed Central

Leather, R P; Shah, D M; Chang, B B; Kaufman, J L

1988-01-01

Distal bypasses for the terminal stages of atherosclerotic occlusive disease manifest by chronic limb-threatening ischemia are among the most challenging arterial reconstructive procedures of surgeons today. The length and low flow rates of distal bypasses often exceed the functional limits of synthetic and even free vein grafts. However, the saphenous vein, when used in situ, provides a unique, viable, physiologically active, and hence antithrombogenic endothelial flow surface that is ideally suited for such bypasses. This paper presents the experience of the Albany Medical Center Hospital with the first 1000 in situ bypasses performed by the valve incision method over a 12-year period. Limb-threatening ischemia was the most common indication for surgery (91%). An in situ bypass was attempted in over 95% of unselected limbs and were completed in situ and in toto in 94%. 66% of the bypasses were carried out to the infrapopliteal level, and in more than 50% of the limbs, the distal vein diameter was less than 3.5 mm. The 30-day patency rate was 95%, and the cumulative patency rates, by life table analysis at 1, 2, 3, 4, and 5 years, were 90%, 86%, 84%, 80%, and 76%, respectively. The vein diameter, specific outflow vessel, level of distal anastomosis (length of bypass), inguinal inflow source used, and instrumental evolution had no significant effect on immediate or long-term bypass performance. PMID:3178331

Patient Bypass Behavior and Critical Access Hospitals: Implications for Patient Retention

ERIC Educational Resources Information Center

Liu, Jiexin (Jason); Bellamy, Gail R.; McCormick, Melissa

2007-01-01

Purpose: To assess the extent of bypass for inpatient care among patients living in Critical Access Hospital (CAH) service areas, and to determine factors associated with bypass, the reasons for bypass, and what CAHs can do to retain patients locally. Methods: Six hundred and forty-seven subjects, aged 18 years and older, who had been admitted to…

Force and pressure-recovery characteristics at supersonic speeds of a conical nose inlet with bypasses discharging outward from the body axis

NASA Technical Reports Server (NTRS)

Beke, Andrew; Allen, J L

1953-01-01

Aerodynamic and performance characteristics of a conical spike nacelle-type inlet with two bypasses are presented at Mach numbers of 1.6, 1.8, and 2.0 for angles of attach up to 90 degrees. The bypasses were located 6 inlet diameters downstream of the inlet and were designed to discharge the bypass mass flow outward from the body axis. The inlet was designed to attain a mass-flow ratio of unity at a Mach number of 2.0. It is shown that discharging the bypass mass flow outward from the body nearly doubles the critical drag of a similar configuration but with bypass discharge in an axial direction. As a result of this greater drag, the net force on the model in the flight direction is reduced when comparison is made with the axial discharge case. The lift and pitching-moment coefficients are slightly higher than those for a configuration without bypasses. Approximately 25 % of the maximum inlet mass flow was discharged through the bypasses, and the pressure-recovery and mass-flow characteristics were in qualitative and quantitative agreement with the results of an investigation of a similar configuration with axial discharge.

[Simplified laparoscopic gastric bypass. Initial experience].

PubMed

Hernández-Miguelena, Luis; Maldonado-Vázquez, Angélica; Cortes-Romano, Pablo; Ríos-Cruz, Daniel; Marín-Domínguez, Raúl; Castillo-González, Armando

2014-01-01

Obesity surgery includes various gastrointestinal procedures. Roux-en-Y gastric bypass is the prototype of mixed procedures being the most practiced worldwide. A similar and novel technique has been adopted by Dr. Almino Cardoso Ramos and Dr. Manoel Galvao called "simplified bypass," which has been accepted due to the greater ease and very similar results to the conventional technique. The aim of this study is to describe the results of the simplified gastric bypass for treatment of morbid obesity in our institution. We performed a descriptive, retrospective study of all patients undergoing simplified gastric bypass from January 2008 to July 2012 in the obesity clinic of a private hospital in Mexico City. A total of 90 patients diagnosed with morbid obesity underwent simplified gastric bypass. Complications occurred in 10% of patients; these were more frequent bleeding and internal hernia. Mortality in the study period was 0%. The average weight loss at 12 months was 72.7%. Simplified gastric bypass surgery is safe with good mid-term results and a loss of adequate weight in 71% of cases.

Turboprop engine and method of operating the same

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

Klees, G.W.; Johnson, P.E.

1986-02-11

This patent describes a turboprop engine consisting of: 1.) A compressor; 2.) A turbine; 3.) A combustion section; 4.) A variable pitch propeller; 5.) A speed reducing transmission; 6.) An air inlet; 7.) An air inlet bypass; 8.) An air outlet bypass duct; 9.) A flow control operatively positioned to receive air flow from the air inlet bypass and air flow from the low pressure compressor component. To direct the air flow to the air outlet bypass duct, and the air flow to the high pressure compressor component, the flow control has a first position where the air flow ismore » from. The high and low pressure compressor components and is directed to the air outlet bypass duct. The flow control has a second position for the air flow from the air inlet bypass duct to the air outlet bypass duct and air from the low pressure compressor component is directed to the high pressure compressor component. A method of operating a turboprop engine.« less

Temporary diabetes insipidus in 2 men after on-pump coronary artery bypass grafting.

PubMed

Uyar, Ihsan Sami; Sahin, Veysel; Akpinar, Besir; Yurtman, Volkan; Abacilar, Feyzi; Okur, Faik Fevzi; Ates, Mehmet

2013-01-01

Many complications have been reported after cardiopulmonary bypass. A common physiologic change during the early postoperative period after cardiopulmonary bypass is increased diuresis. In patients whose urine output is increased, postoperative diabetes insipidus can develop, although reports of this are rare. We present the cases of 2 patients who underwent on-pump coronary artery bypass grafting (with cardiopulmonary bypass). Each was diagnosed with diabetes insipidus postoperatively: a 54-year-old man on the 3rd day, and a 66-year-old man on the 4th day. Each patient recovered from the condition after 6 hours of intranasal therapy with synthetic vasopressin (antidiuretic hormone). The diagnosis of diabetes insipidus should be considered in patients who produce excessive urine early after cardiac surgery in which cardiopulmonary bypass has been used.

Pressure activated stability-bypass-control valves to increase the stable airflow range of a Mach 2.5 inlet with 40 percent internal contraction

NASA Technical Reports Server (NTRS)

Mitchell, G. A.; Sanders, B. W.

1974-01-01

The throat of a Mach 2.5 inlet with a coldpipe termination was fitted with a stability-bypass system. The inlet stable airflow range provided by various stability-bypass entrance configurations in alternate combination with several stability-bypass exit controls was determined for both steady-state conditions and internal transient pulses. Transient results were also obtained for the inlet with a choke point at the diffuser exit. Instart angles of attack were determined for the various stability-bypass entrance configurations. The response of the inlet-coldpipe system to internal and external oscillating disturbances was determined. Poppet valves at the stability-bypass exit provided an inlet stable airflow range of 28 percent or greater at all static and transient conditions.

Femoropopliteal Bypass with Varicose Greater Saphenous Vein

PubMed Central

Mun, Yun Su; Cho, Byung Sun; Jang, Je-Ho; Lee, Moon-Soo; Kwon, Oh Sang

2015-01-01

Surgical bypass for peripheral arterial occlusive disease can be performed using different graft materials. Autogenous greater saphenous vein (GSV) is the treatment of choice because of its superior long-term patency. We report a case of femoropopliteal bypass with varicose GSV in a 77-year-old man who was presented with limb ischemia and both varicose veins. We successfully performed bypass with varicose vein. He has been doing well for 15 months after the operation, and a computed tomography angiography of the lower leg, performed on the 15th postoperative month, demonstrated widely patent femoropopliteal bypass graft and no structural change. PMID:28031670

STA-ACA bypass using the ipsilateral free STA graft as an interposition graft and A3-A3 anastomosis for treatment of bilateral ACA steno-occlusive ischemia.

PubMed

Horiuchi, Tetsuyoshi; Ichinose, Shunsuke; Agata, Masahiro; Ito, Kiyoshi; Hongo, Kazuhiro

2018-04-01

Anterior cerebral artery (ACA)-related ischemia is a rare entity in patients with atherosclerosis. Some surgical treatments are reported to date. We present the modification of intracranial-intracranial and intracranial-extracranial bypasses for symptomatic bilateral ACA steno-occlusive disease. The A3-A3 bypass followed by the superficial temporal artery-ACA bypass using the ipsilateral free superficial temporal artery graft is useful without harvesting of the radial artery. Bilateral ACA steno-occlusive induced ischemia can be treated with tailored bypass procedures.

Cure with ledipasvir/sofosbuvir for chronic hepatitis C virus in an individual with gastric bypass.

PubMed

Johnson, S W; Teachey, A L; Valanejad, S M; Griffin, S M; Weber, S F

2017-10-01

The impact of gastric bypass surgery on the pharmacokinetics of various medications has been reported. Presently, no data exist for the treatment of chronic hepatitis C virus with ledipasvir/sofosbuvir (LDV/SOF) in an individual with a history of gastric bypass. We report the successful cure of an individual who was treated with LDV/SOF who had a history of gastric bypass. The patient tolerated LDV/SOF well while only experiencing a minor headache. Ledipasvir/sofosbuvir treatment may still be effective in those with a history of gastric bypass surgery. © 2017 John Wiley & Sons Ltd.

75 FR 62919 - Notice of Final Federal Agency Actions on the Route 250 Bypass Interchange at McIntire Road...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-13

... on the Route 250 Bypass Interchange at McIntire Road Project in Virginia AGENCY: Federal Highway.... 139(l)(1). The actions relate to the Route 250 Bypass Interchange at McIntire Road project in the City... Virginia: Route 250 Bypass Interchange at McIntire Road. The project would involve construction of a grade...

Distal small bowel bypass for weight regain after gastric bypass: safety and efficacy threshold occurs at <70% bypass.

PubMed

Caruana, Joseph A; Monte, Scott V; Jacobs, David M; Voytovich, Catherine; Ghanim, Husam; Dandona, Paresh

2015-01-01

For patients with poor weight loss (WL) after Roux-en-Y gastric bypass (RYGB) there are few well-tolerated and effective surgical options. Revision to distal bypass by shortening of the common channel (CC) induces significant WL but often produces protein calorie malnutrition (PCM) and severe diarrhea. The aim of this study was to identify a safe and effective threshold for distal small bowel bypass when done for revision of gastric bypass. Academic Institution, United States. We performed revision of RYGB for WL in 20 patients by shortening the CC to a new length of 120-300 cm. The Roux limb length was unchanged. WL and PCM were monitored. A threshold for percent of small bowel bypassed at which PCM was avoided was retrospectively determined. WL was then compared in patients above and below this threshold. Five patients completed a 250-kcal mixed meal challenge before and 3 months after revision to determine selected gut hormone responses. Bypassing ≥70% small bowel resulted in PCM in 4 of 10 patients but in none of 10 patients below that threshold. PCM was observed as late as 2 years after revision and necessitated rerevision by lengthening of the CC in 3 patients. Additionally, nocturnal diarrhea was more common and more intractable when ≥70% bypass was done. Both groups had significant excess body WL over 2 years, but it was greater in patients with ≥70% bypass (47±19 versus 26±17; P<.05). A favorable gut hormone response was observed with 3-hour decrease in glucose-dependent insulinotropic peptide (GIP) by 25% and increase in glucagon-like peptide-1 (GLP-1) by 25%, whereas fasting peptide-YY (PYY) increased by 71% (P<.05 for all). Revision of RYGB to distal bypass when it is <70% of a patient's small bowel length results in an acceptable balance of WL and a positive safety profile. WL may be mediated through an enhanced gut hormone effect, an aversion to ingested fat, and possibly other mechanisms. Copyright © 2015 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

Cerebral activation of mitogen-activated protein kinases after circulatory arrest and low flow cardiopulmonary bypass.

PubMed

Aharon, Alon S; Mulloy, Matthew R; Drinkwater, Davis C; Lao, Oliver B; Johnson, Mahlon D; Thunder, Megan; Yu, Chang; Chang, Paul

2004-11-01

Mitogen-activated protein kinases (MAPK) are important intermediates in the signal transduction pathways involved in neuronal dysfunction following cerebral ischemia-reperfusion injury. One subfamily, extracellular regulated kinase 1/2, has been heavily implicated in the pathogenesis of post-ischemic neuronal damage. However, the contribution of extracellular regulated kinase 1/2 to neuronal damage following deep hypothermic circulatory arrest and low flow cardiopulmonary bypass is unknown. We attempted to correlate the extent of neuronal damage present following deep hypothermic circulatory arrest and low flow cardiopulmonary bypass with phosphorylated extracellular regulated kinase 1/2 expression in the cerebral vascular endothelium. Piglets underwent normal flow cardiopulmonary bypass (n=4) deep hypothermic circulatory arrest (n=6) and low flow cardiopulmonary bypass (n=5). Brains were harvested following 24 h of post-cardiopulmonary bypass recovery. Cerebral cortical watershed zones, hippocampus, basal ganglia, thalamus, cerebellum, mesencephalon, pons and medulla were evaluated using hematoxylin and eosin staining. A section of ischemic cortex was evaluated by immunohistochemistry with rabbit polyclonal antibodies against phosphorylated extracellular regulated kinase 1/2. Compared to cardiopulmonary bypass controls, the deep hypothermic circulatory arrest and low flow cardiopulmonary bypass piglets exhibited diffuse ischemic changes with overlapping severity and distribution. Significant neuronal damage occurred in the frontal watershed zones and basal ganglia of the deep hypothermic circulatory arrest group (P<0.05). No detectable phosphorylated extracellular regulated kinase 1/2 immunoreactivity was found in the cardiopulmonary bypass controls; however, ERK 1/2 immunoreactivity was present in the cerebral vascular endothelium of the deep hypothermic circulatory arrest and low flow cardiopulmonary bypass groups. Our results indicate that phosphorylated extracellular regulated kinase 1/2 may play a prominent role in early cerebral ischemia-reperfusion injury and endothelial dysfunction. The pharmacologic inhibition of extracellular regulated kinase 1/2 represents a new and exciting opportunity for the modulation of cerebral tolerance to low flow cardiopulmonary bypass and deep hypothermic circulatory arrest.

Alterations of sucrose preference after Roux-en-Y gastric bypass.

PubMed

Bueter, M; Miras, A D; Chichger, H; Fenske, W; Ghatei, M A; Bloom, S R; Unwin, R J; Lutz, T A; Spector, A C; le Roux, C W

2011-10-24

Roux-en-Y gastric bypass (gastric bypass) patients reportedly have changes in perception and consumption of sweet-tasting foods. This study aimed to further investigate alterations in sweet food intake in rats and sucrose detection in humans after gastric bypass. Wistar rats were randomized to gastric bypass or sham-operations and preference for sucrose (sweet), sodium chloride (salty), citric acid (sour) and quinine hydrochloride (bitter) was assessed with standard two-bottle intake tests (vs. water). Intestinal T1R2 and T1R3 expression and plasma levels of glucagon-like-peptide 1 (GLP-1) and peptide YY (PYY) were measured. Furthermore, obese patients and normal weight controls were tested for sucrose taste detection thresholds pre- and postoperatively. Visual analogue scales measuring hedonic perception were used to determine the sucrose concentration considered by patients and controls as "just about right" pre- and postoperatively. Gastric bypass reduced the sucrose intake relative to water in rats (p<0.001). Preoperative sucrose exposure reduced this effect. Preference or aversion for compounds representative of other taste qualities in naïve rats remained unaffected. Intestinal T1R2 and T1R3 expression was significantly decreased in the alimentary limb while plasma levels of GLP-1 and PYY were elevated after bypass in rats (p=0.01). Bypass patients showed increased taste sensitivity to low sucrose concentrations compared with controls (p<0.05), but both groups considered the same sucrose concentration as "just about right" postoperatively. In conclusion, gastric bypass reduces sucrose intake relative to water in sucrose-naïve rats, but preoperative sucrose experience attenuates this effect. Changes in sucrose taste detection do not predict hedonic taste ratings of sucrose in bypass patients which remain unchanged. Thus, factors other than the unconditional affective value of the taste may also play a role in determining food preferences after gastric bypass. Copyright © 2011 Elsevier Inc. All rights reserved.

Bypassing birthing centres for child birth: a community-based study in rural Chitwan Nepal.

PubMed

Shah, Rajani

2016-10-21

Child delivery in a health facility is important to reduce maternal mortality. Bypassing nearby birthing facility to deliver at a hospital is common in developing countries including Nepal. Very little is known about the extent and determinants of bypassing the birthing centres in Nepal. This study measures the status of bypassing, characteristics of bypassers and their reasons for bypassing. A community-based cross-sectional study was carried out in six rural village development committees of Chitwan district of Nepal. Structured interviews were conducted with 263 mothers who had given birth at a health facility and whose nearest facility was a birthing centre. Descriptive statistics, univariate and multivariable logistic regression analysis were performed. More than half of the mothers had bypassed the nearer birthing centres to deliver at hospital. Living in plain area [aOR: 2.467; 95 % CI: 1.005-6.058], higher wealth index [aOR: 4.981; 95 % CI: 2.482-9.999], advantaged caste/ethnicity [aOR: 2.172; 95 % CI: 1.153-4.089], older age [aOR: 2.222; 95 % CI: 1.050-4.703] and first birth [aOR: 2.032; 95 % CI: 1.060-3.894] were associated with higher likelihood of bypassing. Among the reasons of bypassing as reported by the bypassers, lack of operation, video x-ray, and blood test facilities were the most common ones, followed by the lack of medicines/drugs and equipment, lack of skilled service provider, and inadequate physical facilities, among others. Quality of service at the birthing centres needs to be given a high consideration to increase their use as well as to ensure an equitable access to the quality care by all.

Abdominal Pain After Roux-En-Y Gastric Bypass for Morbid Obesity.

PubMed

Mala, Tom; Høgestøl, Ingvild

2018-05-01

Roux-en-Y gastric bypass is widely used as treatment of morbid obesity. Weight loss, effects on obesity-related co-morbidities and quality of life are well documented post Roux-en-Y gastric bypass. Other outcome measures are less well studied. This review explores aspects of prevalence, diagnostic evaluations, etiology, and treatment of abdominal pain specific to Roux-en-Y gastric bypass. The review is based on PubMed searches and clinical experience with Roux-en-Y gastric bypass. Symptoms in the early postoperative phase (<30 days) were not included. Based on limited evidence, up to about 30% of the patients may perceive recurrent abdominal pain post Roux-en-Y gastric bypass in the long term. A substantial subset of patients will need health-care evaluation for acute abdominal pain and hospital admission. The etiology of abdominal pain is heterogeneous and includes gallstone-related disease, intestinal obstruction, anastomotic ulcerations and strictures, intestinal dysmotility, dysfunctional eating, and food intolerance. Surgical treatment and guidance on diet and eating habits may allow symptom relief. The cause of pain remains undefined for a subset of patients. Impact of abdominal pain post Roux-en-Y gastric bypass on the perception of well-being, quality of life, and patient satisfaction with the procedure needs to be further evaluated and may be influenced by complex interactions between new symptoms post Roux-en-Y gastric bypass and relief of pre-existing symptoms. Abdominal pain should be part of follow-up consultations post Roux-en-Y gastric bypass. Future studies should focus on combined evaluations before and after surgery to enlighten potential casual relationships between abdominal pain and Roux-en-Y gastric bypass.

Extracorporeal membrane oxygenation

MedlinePlus

ECMO; Heart-lung bypass - infants; Bypass - infants; Neonatal hypoxia - ECMO; PPHN - ECMO; Meconium aspiration - ECMO; MAS - ECMO ... back into the bloodstream of a very ill baby. This system provides heart-lung bypass support outside of the baby's body. ...

Turbojet-exhaust-nozzle secondary-airflow pumping as an exit control of an inlet-stability bypass system for a Mach 2.5 axisymmetric mixed-compression inlet. [Lewis 10- by 10-ft. supersonic wind tunnel test

NASA Technical Reports Server (NTRS)

Sanders, B. W.

1980-01-01

The throat of a Mach 2.5 inlet that was attached to a turbojet engine was fitted with large, porous bleed areas to provide a stability bypass system that would allow a large, stable airflow range. Exhaust-nozzle, secondary-airflow pumping was used as the exit control for the stability bypass airflow. Propulsion system response and stability bypass performance were obtained for several transient airflow disturbances, both internal and external. Internal airflow disturbances included reductions in overboard bypass airflow, power lever angle, and primary-nozzle area, as well as compressor stall. Nozzle secondary pumping as a stability bypass exit control can provide the inlet with a large stability margin with no adverse effects on propulsion system performance.

Eversion endarterectomy of the proximal superficial femoral artery: a source of inflow for distal bypass in case of hostile groin.

PubMed

Cavallaro, Antonio; Sterpetti, Antonio V; Dimarzo, Luca

2012-08-01

In selected patients, eversion endarterectomy of the proximal superficial femoral artery can represent a valid inflow for a distal bypass to avoid a "hostile" groin. Patency rates and limb salvage rates were retrospectively analysed for 21 consecutive patients who underwent distal bypass for severe lower limb ischemia and in whom the proximal superficial femoral artery was reopened with an eversion endarterectomy. In all patients, this technique was used to avoid a hostile groin. Five-year cumulative patency rates were 53% for femoropopliteal bypasses and 40% for femorotibial bypasses. Overall 5-y cumulative limb salvage was 72%. In case of hostile groin, eversion endarterectomy of the proximal superficial femoral artery is a valid solution to provide inflow for a distal bypass. Copyright © 2012 Elsevier Inc. All rights reserved.

Rankine cycle condenser pressure control using an energy conversion device bypass valve

DOEpatents

Ernst, Timothy C; Nelson, Christopher R; Zigan, James A

2014-04-01

The disclosure provides a waste heat recovery system and method in which pressure in a Rankine cycle (RC) system of the WHR system is regulated by diverting working fluid from entering an inlet of an energy conversion device of the RC system. In the system, an inlet of a controllable bypass valve is fluidly coupled to a working fluid path upstream of an energy conversion device of the RC system, and an outlet of the bypass valve is fluidly coupled to the working fluid path upstream of the condenser of the RC system such that working fluid passing through the bypass valve bypasses the energy conversion device and increases the pressure in a condenser. A controller determines the temperature and pressure of the working fluid and controls the bypass valve to regulate pressure in the condenser.

Contrast MR of the brain after high-perfusion cardiopulmonary bypass

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

Simonson, T.M.; Yuh, W.T.C.; Hindman, B.J.

1994-01-01

To study the efficacy of contrast MR imaging in the evaluation of central nervous system complications in the cardiopulmonary bypass patient and attempt to explain their pathophysiology based on the MR appearance and the cardiopulmonary bypass protocol. Nineteen patients were prospectively studied with contrast MR examinations the day before and 3 to 7 days after cardiopulmonary bypass, to determine the nature, extent, and number of new postoperative MR abnormalities. Cardiopulmonary bypass parameters used in our institution included: membrane oxygenation, arterial filtration with a pore size of 25 [mu]m, and a relatively high perfusion rate to produce a cardiac index ofmore » 2.0 to 2.5 L min per m[sup 2]. The preoperative noncontrast MR examination showed age-related changes and/or signs of ischemia in 60% of patients on the day before surgery. However, there was no abnormal enhancement or new T2 abnormalities on any postoperative MR examination to suggest hypoperfusion or emboli. None of the 19 patients developed overt neurologic deficits postoperatively. Review of the cardiopulmonary bypass protocol used indicated significant variations in technique at different institutions. Contrast MR imaging demonstrated no new abnormalities in patients after cardiopulmonary bypass performed with strict in-line arterial filtration and relatively high perfusion. MR imaging is feasible in the early postoperative period after cardiopulmonary bypass and may offer a convenient method for evaluation of the neurologic impact of technical factors associated with cardiopulmonary bypass. 17 refs.« less

Postoperative Dysphagia in Debranching Thoracic Endovascular Aortic Repair with Retroesophageal Carotid-Carotid Bypass.

PubMed

Yoneyama, Fumiya; Sato, Fujio; Tokunaga, Chiho; Sakamoto, Hiroaki; Enomoto, Yoshiharu; Watanabe, Yutaka; Hiramatsu, Yuji

2017-08-01

A carotid-carotid bypass is commonly used in debranching thoracic endovascular aortic repair. When the bypass graft is placed in the retroesophageal position, the esophagus may be compressed by the graft from behind. Therefore, dysphagia may occur postoperatively as a serious complication. To avoid this issue, we recommend placing the bypass graft below the cricoid cartilage. Copyright © 2017 Elsevier Inc. All rights reserved.

Cardiopulmonary bypass for pediatric cardiac surgery.

PubMed

Hirata, Yasutaka

2018-02-01

The management of cardiopulmonary bypass for pediatric cardiac surgery is more challenging than that in adults due to the smaller size, immaturity, and complexity of the anatomy in children. Despite major improvements in cardiopulmonary bypass, there remain many subjects of debate. This review article discusses the physiology of cardiopulmonary bypass for pediatric and congenital heart surgery, including topics related to hemodilution, hypothermia, acid-base strategies, inflammatory response, and myocardial protection.

Diagnostic tools for post-gastric bypass hypoglycaemia.

PubMed

Emous, M; Ubels, F L; van Beek, A P

2015-10-01

In spite of its evident success, several late complications can occur after gastric bypass surgery. One of these is post-gastric bypass hypoglycaemia. No evidence-based guidelines exist in the literature on how to confirm the presence of this syndrome. This study aims to describe and compare the tests aimed at making a diagnosis of post-gastric bypass hypoglycaemia and to provide a diagnostic approach based upon the available evidence. A search was conducted in PubMed, Cochrane and Embase. A few questionnaires have been developed to measure the severity of symptoms in post-gastric bypass hypoglycaemia but none has been validated. The gold standard for provocation of a hypoglycaemic event is the oral glucose tolerance test or the liquid mixed meal tolerance test. Both show a high prevalence of hypoglycaemia in post-gastric bypass patients with and without hypoglycaemic complaints as well as in healthy volunteers. No uniformly established cut-off values for glucose concentrations are defined in the literature for the diagnosis of post-gastric bypass hypoglycaemia. For establishing an accurate diagnosis of post-gastric bypass hypoglycaemia, a validated questionnaire, in connection with the diagnostic performance of provocation tests, is the most important thing missing. Given these shortcomings, we provide recommendations based upon the current literature. © 2015 World Obesity.

Coronary Artery Bypass Surgery: MedlinePlus Health Topic

MedlinePlus

... Coronary Artery Bypass (Texas Heart Institute) Also in Spanish Coronary Artery Bypass Graft Surgery (Beyond the Basics) ( ... Radiology, Radiological Society of North America) Also in Spanish Living With Cardiac Rehabilitation: MedlinePlus Health Topic (National ...

Bypass transition in boundary layers including curvature and favorable pressure gradient effects

NASA Technical Reports Server (NTRS)

Volino, R. J.; Simon, T. W.

1991-01-01

Recent studies of 2-D boundary layers undergoing bypass transition were reviewed. Bypass transition is characterized by the sudden appearance of turbulent spots in boundary layer without first the regular, observable growth of disturbances predicted by linear stability theory. There are no standard criteria or parameters for defining bypass transition, but it is known to be the mode of transition when the flow is disturbed by perturbations of sufficient amplitude.

Bypass transition to turbulence and research Desiderata

NASA Technical Reports Server (NTRS)

Morkovin, M. V.

1985-01-01

Bypass transitions are seldom mentioned in texts or meetings on instability and transition to wall turbulence. The nature of a number of bypass transitions is illustrated by example. Until this characteristics is truly understood predicting transition on the basis of theory or statistically inadequate correlations (as they all are) entails risks that should be considered in justifying any design involving transition. A historical overview of bypass transition identified on blunt bodies is given.

Active bypass flow control for a seal in a gas turbine engine

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

Ebert, Todd A.; Kimmel, Keith D.

An active bypass flow control system for controlling bypass compressed air based upon leakage flow of compressed air flowing past an outer balance seal between a stator and rotor of a first stage of a gas turbine in a gas turbine engine is disclosed. The active bypass flow control system is an adjustable system in which one or more metering devices may be used to control the flow of bypass compressed air as the flow of compressed air past the outer balance seal changes over time as the outer balance seal between the rim cavity and the cooling cavity wears.more » In at least one embodiment, the metering device may include a valve formed from one or more pins movable between open and closed positions in which the one pin at least partially bisects the bypass channel to regulate flow.« less

Making a mixed-model line more efficient and flexible by introducing a bypass line

NASA Astrophysics Data System (ADS)

Matsuura, Sho; Matsuura, Haruki; Asada, Akiko

2017-04-01

This paper provides a design procedure for the bypass subline in a mixed-model assembly line. The bypass subline is installed to reduce the effect of the large difference in operation times among products assembled together in a mixed-model line. The importance of the bypass subline has been increasing in association with the rising necessity for efficiency and flexibility in modern manufacturing. The main topics of this paper are as follows: 1) the conditions in which the bypass subline effectively functions, and 2) how the load should be distributed between the main line and the bypass subline, depending on production conditions such as degree of difference in operation times among products and the mixing ratio of products. To address these issues, we analyzed the lower and the upper bounds of the line length. Based on the results, a design procedure and a numerical example are demonstrated.

Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.; Schunk, Richard G.

2011-01-01

An active thermal control system architecture has been modified to include a regenerative heat exchanger (regenerator) inboard of the radiator. Rather than using a radiator bypass valve a regenerative heat exchanger is placed inboard of the radiators. A regenerator cold side bypass valve is used to set the return temperature. During operation, the regenerator bypass flow is varied, mixing cold radiator return fluid and warm regenerator outlet fluid to maintain the system setpoint. At the lowest heat load for stable operation, the bypass flow is closed off, sending all of the flow through the regenerator. This lowers the radiator inlet temperature well below the system set-point while maintaining full flow through the radiators. By using a regenerator bypass flow control to maintain system setpoint, the required minimum heat load to avoid radiator freezing can be reduced by more than half compared to a radiator bypass system.

Sorbent-Based Atmosphere Revitalization System

NASA Technical Reports Server (NTRS)

Knox, James C (Inventor); Miller, Lee A. (Inventor)

2017-01-01

The present invention is a sorbent-based atmosphere revitalization (SBAR) system using treatment beds each having a bed housing, primary and secondary moisture adsorbent layers, and a primary carbon dioxide adsorbent layer. Each bed includes a redirecting plenum between moisture adsorbent layers, inlet and outlet ports connected to inlet and outlet valves, respectively, and bypass ports connected to the redirecting plenums. The SBAR system also includes at least one bypass valve connected to the bypass ports. An inlet channel connects inlet valves to an atmosphere source. An outlet channel connects the bypass valve and outlet valves to the atmosphere source. A vacuum channel connects inlet valves, the bypass valve and outlet valves to a vacuum source. In use, one bed treats air from the atmosphere source while another bed undergoes regeneration. During regeneration, the inlet, bypass, and outlet valves sequentially open to the vacuum source, removing accumulated moisture and carbon dioxide.

Heating and cooling system for an on-board gas adsorbent storage vessel

DOEpatents

Tamburello, David A.; Anton, Donald L.; Hardy, Bruce J.; Corgnale, Claudio

2017-06-20

In one aspect, a system for controlling the temperature within a gas adsorbent storage vessel of a vehicle may include an air conditioning system forming a continuous flow loop of heat exchange fluid that is cycled between a heated flow and a cooled flow. The system may also include at least one fluid by-pass line extending at least partially within the gas adsorbent storage vessel. The fluid by-pass line(s) may be configured to receive a by-pass flow including at least a portion of the heated flow or the cooled flow of the heat exchange fluid at one or more input locations and expel the by-pass flow back into the continuous flow loop at one or more output locations, wherein the by-pass flow is directed through the gas adsorbent storage vessel via the by-pass line(s) so as to adjust an internal temperature within the gas adsorbent storage vessel.

Analysis of pesticides in surface water and sediment from Yolo Bypass, California, 2004-2005

USGS Publications Warehouse

Smalling, Kelly L.; Orlando, James L.; Kuivila, Kathryn

2005-01-01

Inputs to the Yolo Bypass are potential sources of pesticides that could impact critical life stages of native fish. To assess the direct inputs during inundation, pesticide concentrations were analyzed in water, in suspended and bed-sediment samples collected from six source watersheds to the Yolo Bypass, and from three sites within the Bypass in 2004 and 2005. Water samples were collected in February 2004 from the six input sites to the Bypass during the first flood event of the year representing pesticide inputs during high-flow events. Samples were also collected along a transect across the Bypass in early March 2004 and from three sites within the Bypass in the spring of 2004 under low-flow conditions. Low-flow data were used to understand potential pesticide contamination and its effects on native fish if water from these areas were used to flood the Bypass in dry years. To assess loads of pesticides to the Bypass associated with suspended sediments, large-volume water samples were collected during high flows in 2004 and 2005 from three sites, whereas bed sediments were collected from six sites in the fall of 2004 during the dry season. Thirteen current-use pesticides were detected in surface water samples collected during the study. The highest pesticide concentrations detected at the input sites to the Bypass corresponded to the first high-flow event of the year. The highest pesticide concentrations at the two sites sampled within the Bypass during the early spring were detected in mid-April following a major flood event as the water began to subside. The pesticides detected and their concentrations in the surface waters varied by site; however, hexazinone and simazine were detected at all sites and at some of the highest concentrations. Thirteen current-use pesticides and three organochlorine insecticides were detected in bed and suspended sediments collected in 2004 and 2005. The pesticides detected and their concentrations varied by site and sediment sample type. Trifluralin, p,p'-DDE, and p,p'-DDT were highest in the bed sediments, whereas oxyfluorfen and thiobencarb were highest in the suspended sediments. With the exception of the three organochlorine insecticides, suspended sediments had higher pesticide concentrations compared with bed sediments, indicating the potential for pesticide transport throughout the Bypass, especially during high-flow events. Understanding the distribution of pesticides between the water and sediment is needed to assess fate and transport within the Bypass and to evaluate the potential effects on native fish.

Comparison of changes in lipid profile after bilio-intestinal bypass and gastric banding in patients with morbid obesity.

PubMed

Corradini, Stefano Ginanni; Eramo, Annarita; Lubrano, Carla; Spera, Giovanni; Cornoldi, Alessandra; Grossi, Antonio; Liguori, Francesca; Siciliano, Maria; Pisanelli, Massimo Codacci; Salen, Gerald; Batta, Ashok Kumir; Attili, Adolfo Francesco; Badiali, Marco

2005-03-01

The presence of hypercholesterolemia is currently not considered a selection criteria for performing gastric restrictive or diversionary bariatric surgery. We prospectively investigated the effects of the bilio-intestinal bypass (BI-bypass) with a wide cholecysto-jejunal anastomosis and of adjustable gastric banding (AGB) on blood lipid concentrations in obese patients. To clarify the mechanism of the hypocholesterolemic effect of the BI-bypass, daily fecal sterol excretion was measured by gas-liquid chromatography (GLC). At 1 year after BI-bypass compared to baseline, the hypercholesterolemic (n=18) and the normocholesterolemic (n=19) patients significantly reduced total (-38% and -27%, respectively), LDL (-47% and -24%, respectively) and HDL (-11% and -13%, respectively) cholesterol and total / HDL cholesterol ratio (-25% and -13%, respectively). At 1 year after AGB, the total / HDL cholesterol ratio was significantly decreased (-11%) compared to baseline in hypercholesterolemic (n=12) but not in normocholesterolemic (n=6) patients, while total and LDL cholesterol were not affected in both groups. At 3 years after BI-bypass compared to baseline, the hypercholesterolemic (n=9) and the normocholesterolemic (n=11) patients significantly reduced total (-43% and -28%, respectively) and LDL (-53% and -29%, respectively) cholesterol and total / HDL cholesterol ratio (-38% and -21%, respectively). The BI-bypass induced a significant (P <0.005; n=7) 6-fold increase in mean fecal cholesterol output. The BI-bypass but not the AGB leads to a persistent and marked beneficial effect on blood LDL cholesterol associated with an increased cholesterol fecal output. BI-bypass but not AGB is indicated in morbidly obese patients with hypercholesterolemia.

Retrospective Analyses of Esophageal Bypass Surgery for Patients with Esophagorespiratory Fistulas Caused by Esophageal Carcinomas.

PubMed

Nakajima, Yasuaki; Kawada, Kenro; Tokairin, Yutaka; Miyawaki, Yutaka; Okada, Takuya; Miyake, Satoshi; Kawano, Tatsuyuki

2016-05-01

Esophagorespiratory fistula (ERF) caused by esophageal carcinoma is a fatal complication. In our institution, esophageal bypass surgery has been indicated when possible. We herein retrospectively describe the clinical results of esophageal bypass surgery for ERF. Between April 2001 and March 2015, 20 patients with ERF underwent esophageal bypass surgery. For these patients, the clinical safety, validity, and effectiveness of esophageal bypass surgery were examined and compared with the results of bypass surgery without ERF. Eight patients developed ERF at the initial diagnosis, while 10 patients developed ERF during and after chemoradiotherapy. Postoperative complications such as pneumonia, surgical site infection, and anastomotic leakage developed in 12, 5, and 1 patient, respectively. All the patients could eat solid foods at a median of 9 postoperative days. Two patients died within 30 days after the operation and 1 patient developed in-hospital death. Fourteen patients received chemo(radio)therapy after the operation. The median overall survival was 244 days and the one-year and three-year overall survival rates were 45.7 and 15.3 %, respectively. There was no significant difference in terms of the intraoperative findings, postoperative morbidities, and short-term and long-term clinical results between the two groups. Esophageal bypass surgery for ERF is not considered to be highly invasive or risky compared with bypass surgery without ERF. After the operation, respiratory symptoms caused by ERF may improve and oral intake can be achieved. Esophageal bypass surgery should therefore be aggressively performed for patients with a tolerable performance status.

The contribution of malabsorption to the reduction in net energy absorption after long-limb Roux-en-Y gastric bypass.

PubMed

Odstrcil, Elizabeth A; Martinez, Juan G; Santa Ana, Carol A; Xue, Beiqi; Schneider, Reva E; Steffer, Karen J; Porter, Jack L; Asplin, John; Kuhn, Joseph A; Fordtran, John S

2010-10-01

Roux-en-Y gastric bypass (RYGB) restricts food intake, and when the Roux limb is elongated to 150 cm, the procedure is believed to induce malabsorption. Our objective was to measure total reduction in intestinal absorption of combustible energy after RYGB and the extent to which this was due to restriction of food intake or malabsorption of ingested macronutrients. Long-limb RYGB was performed in 9 severely obese patients. Dietary intake and intestinal absorption of fat, protein, carbohydrate, and combustible energy were measured before and at 2 intervals after bypass. By using coefficients of absorption to measure absorptive function, equations were developed to calculate the daily gram and kilocalorie quantities of ingested macronutrients that were not absorbed because of malabsorption or restricted food intake. Coefficients of fat absorption were 92 ± 1.3% before bypass, 72 ± 5.5% 5 mo after bypass, and 68 ± 8.7% 14 mo after bypass. There were no statistically significant effects of RYGB on protein or carbohydrate absorption coefficients, although protein coefficients decreased substantially in some patients. Five months after bypass, malabsorption reduced absorption of combustible energy by 124 ± 57 kcal/d, whereas restriction of food intake reduced energy absorption by 2062 ± 271 kcal/d. Fourteen months after bypass, malabsorption reduced energy absorption by 172 ± 60 kcal/d compared with 1418 ± 171 kcal/d caused by restricted food intake. On average, malabsorption accounted for ≈6% and 11% of the total reduction in combustible energy absorption at 5 and 14 mo, respectively, after this gastric bypass procedure.

Increased postprandial energy expenditure may explain superior long term weight loss after Roux-en-Y gastric bypass compared to vertical banded gastroplasty.

PubMed

Werling, Malin; Olbers, Torsten; Fändriks, Lars; Bueter, Marco; Lönroth, Hans; Stenlöf, Kaj; le Roux, Carel W

2013-01-01

Gastric bypass results in greater weight loss than Vertical banded gastroplasty (VBG), but the underlying mechanisms remain unclear. In addition to effects on energy intake the two bariatric techniques may differentially influence energy expenditure (EE). Gastric bypass in rats increases postprandial EE enough to result in elevated EE over 24 hours. This study aimed to investigate alterations in postprandial EE after gastric bypass and VBG in humans. Fourteen women from a randomized clinical trial between gastric bypass (n = 7) and VBG (n = 7) were included. Nine years postoperatively and at weight stability patients were assessed for body composition and calorie intake. EE was measured using indirect calorimetry in a respiratory chamber over 24 hours and focused on the periods surrounding meals and sleep. Blood samples were analysed for postprandial gut hormone responses. Groups did not differ regarding body composition or food intake either preoperatively or at study visit. Gastric bypass patients had higher EE postprandially (p = 0.018) and over 24 hours (p = 0.048) compared to VBG patients. Postprandial peptide YY (PYY) and glucagon like peptide 1 (GLP-1) levels were higher after gastric bypass (both p<0.001). Gastric bypass patients have greater meal induced EE and total 24 hours EE compared to VBG patients when assessed 9 years postoperatively. Postprandial satiety gut hormone responses were exaggerated after gastric bypass compared to VBG. Long-term weight loss maintenance may require significant changes in several physiological mechanisms which will be important to understand if non-surgical approaches are to mimic the effects of bariatric surgery.

Heart bypass surgery

MedlinePlus Videos and Cool Tools

Heart bypass surgery begins with an incision made in the chest, with the breastbone cut exposing the heart. Next, a portion of the saphenous vein is ... used to bypass the blocked arteries in the heart. The venous graft is sewn to the aorta ...

Nutrient deficiency and obstetrical outcomes in pregnant women following Roux-en-Y gastric bypass: A retrospective Danish cohort study with a matched comparison group.

PubMed

Hammeken, Lianna Hede; Betsagoo, Ramsina; Jensen, Ann Nygaard; Sørensen, Anne Nødgaard; Overgaard, Charlotte

2017-09-01

Roux-en-Y gastric bypass surgery and small-for-gestational-age births are known to be associated although the etiology is not fully understood. This study aimed to investigate pregnancy outcomes and maternal nutritional status among pregnant women with a history of Roux-en-Y gastric bypass using maternal anemia and gestational weight gain as indicators of micronutrient and macronutrient deficiency in pregnancy. The study was designed as a retrospective matched cohort study. All Roux-en-Y-gastric-bypass-operated pregnant women (n=151) who were followed in the outpatient obstetric clinic at Aalborg University Hospital in Denmark and gave birth between 1 January 2010 and 31 December 2013 were included. Each Roux-en-Y-gastric-bypass-operated woman was closely matched with a non-Roux-en-Y-gastric-bypass-operated woman. Primary outcomes were small-for-gestational-age birth, maternal anemia and gestational weight gain. The two groups (matched 1:1) were compared by paired tests on all measures, conditional logistic regression for paired binary data and the paired t-test or Wilcoxon signed-rank test for paired continuous data. The risk of small-for-gestational-age birth (odds ratio (OR)=2.67, 95% confidence interval (CI); 1.04-6.82) and maternal anemia (OR=3.0, 95% CI; 1.09-8.25) were significantly increased for the Roux-en-Y gastric bypass group compared to the non-Roux-en-Y gastric bypass group. No significant difference was found in gestational weight gain (p=0.169) between women with a history of Roux-en-Y gastric bypass (11.51kg±8.97 standard deviation (SD)) and non- Roux-en-Y-gastric-bypass-operated women (12.18kg±6.28 SD). A history of Roux-en-Y gastric bypass surgery increases the risk of small-for-gestational-age birth and anemia, while a finding of differences in gestational weight gain is uncorroborated. Our findings suggest a role of micronutrient deficiency rather than reduced gestational weight gain in the etiology of small-for-gestational-age birth among women with a history of Roux-en-Y gastric bypass surgery. Copyright © 2017 Elsevier B.V. All rights reserved.

Massive sediment bypassing on the lower shoreface offshore of a wide tidal inlet: Cat Island Pass, Louisiana

USGS Publications Warehouse

Jaffe, B.E.; List, J.H.; Sallenger, A.H.

1997-01-01

Analysis of a series of historical bathymetric and shoreline surveys along the Louisiana coast west of the Mississippi River mouth detected a large area of deposition in water depths of 2.0–8.5 m offshore of a 9-km-wide tidal inlet, the Cat Island Pass/Wine Island Pass system. A 59.9 · 106 m3 sandy deposit formed from the 1930s–1980s, spanning 27 km in the alongshore direction, delineating the transport pathway for sediment bypassing offshore of the inlet on the shoreface. Bypassing connected the shorefaces of two barrier island systems, the Isles Dernieres and the Bayou Lafourche.The processes responsible for formation of this deposit are not well understood, but sediment-transport modeling suggests that sediment is transported primarily by wind-driven coastal currents during large storms and hurricanes. Deposition appears to be related to changes in shoreline orientation, closing of transport pathways into a large bay to the east and the presence of tidal inlets. This newly documented type of bypassing, an offshore bypassing of the inlet system, naturally nourished the immediate downdrift area, the eastern Isles Dernieres, where shoreface and shoreline erosion rates are about half of pre-bypassing rates. Erosion rates remained the same farther downdrift, where bypassing has not yet reached. As this offshore bypassing continues, the destruction of the Isles Dernieres will be slowed.

Off-pump grafting does not reduce postoperative pulmonary dysfunction.

PubMed

Izzat, Mohammad Bashar; Almohammad, Farouk; Raslan, Ahmad Fahed

2017-02-01

Objectives Pulmonary dysfunction is a recognized postoperative complication that may be linked to use of cardiopulmonary bypass. The off-pump technique of coronary artery bypass aims to avoid some of the complications that may be related to cardiopulmonary bypass. In this study, we compared the influence of on-pump or off-pump coronary artery bypass on pulmonary gas exchange following routine surgery. Methods Fifty patients (mean age 60.4 ± 8.4 years) with no preexisting lung disease and good left ventricular function undergoing primary coronary artery bypass grafting were prospectively randomized to undergo surgery with or without cardiopulmonary bypass. Alveolar/arterial oxygen pressure gradients were calculated prior to induction of anesthesia while the patients were breathing room air, and repeated postoperatively during mechanical ventilation and after extubation while inspiring 3 specific fractions of oxygen. Results Baseline preoperative arterial blood gases and alveolar/arterial oxygen pressure gradients were similar in both groups. At both postoperative stages, the partial pressure of arterial oxygen and alveolar/arterial oxygen pressure gradients increased with increasing fraction of inspired oxygen, but there were no statistically significant differences between patients who underwent surgery with or without cardiopulmonary bypass, either during ventilation or after extubation. Conclusions Off-pump surgery is not associated with superior pulmonary gas exchange in the early postoperative period following routine coronary artery bypass grafting in patients with good left ventricular function and no preexisting lung disease.

Left heart bypass support with the Rotaflow Centrifugal Pump® as a bridge to decision and recovery in an adult.

PubMed

Kashiwa, Koichi; Nishimura, Takashi; Saito, Aya; Kubo, Hitoshi; Fukaya, Aoi; Tamai, Hisayoshi; Yambe, Tomoyuki; Kyo, Shunei; Ono, Minoru

2012-06-01

Since left heart bypass or biventricular circulatory assist with an extracorporeal centrifugal pump as a bridge to decision or recovery sometimes requires long-time support, the long-term durability of extracorporeal centrifugal pumps is crucial. The Rotaflow Centrifugal Pump(®) (MAQUET Cardiopulmonary AG, Hirrlingen, Germany) is one of the centrifugal pumps available for long-term use in Japan. However, there have been few reports of left heart bypass or biventricular circulatory support over the mid-term. This is a case report of left heart bypass support with the Rotaflow Centrifugal Pump(®) as a bridge to decision and recovery for an adult patient who could not be weaned from cardiopulmonary bypass and percutaneous cardiopulmonary support after cardiac surgery. We could confirm that the patient's consciousness level was normal; however, the patient could not be weaned from the left heart bypass support lasting 1 month. Therefore, the circulatory assist device was switched to the extracorporeal Nipro ventricular assist device (VAD). This time, left heart bypass support could be maintained for 30 days using a single Rotaflow Centrifugal Pump(®). There were no signs of hemolysis during left heart bypass support. The Rotaflow Centrifugal Pump(®) itself may be used as a device for a bridge to decision or recovery before using a VAD in cardiogenic shock patients.

Noninvasive detection of coronary artery bypass graft patency by intravenous electron beam computed tomographic angiography.

PubMed

Yamakami, Shoji; Toyama, Junji; Okamoto, Mitsuhiro; Matsushita, Toyoaki; Murakami, Yoshimasa; Ogata, Masaki; Ito, Shigenori; Fukutomi, Tatsuya; Okayama, Naotsuka; Itoh, Makoto

2003-11-01

This study evaluates the usefullness of intravenous electron beam computed tomographic angiography (EBA) for the detection of coronary artery bypass graft patency in 43 patients (33 men and 10 women, mean age, 65 years) who had coronary artery bypass graft surgery. EBA was performed a few days before selective bypass graft angiography (SGA). Forty axial cross-sections of angiographic images of the heart were acquired consecutively by an electrocardiographic trigger signal at 40% of the RR interval, which corresponds to the end-systolic phase. EBA data were reconstructed as a three-dimensional shaded surface display of the heart and bypass grafts. Detectability of the patency of bypass gratis was evaluated, taking selective angiographic images of the bypass grafts as a gold standard. One hundred and nine grafts (96%) out of 114 grafts were subjected to evaluation: 37 grafts were left internal mammary artery grafts (LIMA), 7 were right internal mammary artery grafts (RIMA), 6 were gastroepiploic artery grafts (GEA), 7 were free gastroepiploic artery grafts with venous drainage (free-GEA), 7 were radial artery grafts (RAG), and 45 were saphenous vein gratis (SVG). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of EBA were 98%, 100%, 100%, 91%, and 98%, respectively. EBA sampled at the end-systolic period was determined to be useful for the detection of coronary artery bypass graft patency and occlusion.

Effect of Laparoscopic Sleeve Gastrectomy vs Laparoscopic Roux-en-Y Gastric Bypass on Weight Loss in Patients With Morbid Obesity: The SM-BOSS Randomized Clinical Trial.

PubMed

Peterli, Ralph; Wölnerhanssen, Bettina Karin; Peters, Thomas; Vetter, Diana; Kröll, Dino; Borbély, Yves; Schultes, Bernd; Beglinger, Christoph; Drewe, Jürgen; Schiesser, Marc; Nett, Philipp; Bueter, Marco

2018-01-16

Sleeve gastrectomy is increasingly used in the treatment of morbid obesity, but its long-term outcome vs the standard Roux-en-Y gastric bypass procedure is unknown. To determine whether there are differences between sleeve gastrectomy and Roux-en-Y gastric bypass in terms of weight loss, changes in comorbidities, increase in quality of life, and adverse events. The Swiss Multicenter Bypass or Sleeve Study (SM-BOSS), a 2-group randomized trial, was conducted from January 2007 until November 2011 (last follow-up in March 2017). Of 3971 morbidly obese patients evaluated for bariatric surgery at 4 Swiss bariatric centers, 217 patients were enrolled and randomly assigned to sleeve gastrectomy or Roux-en-Y gastric bypass with a 5-year follow-up period. Patients were randomly assigned to undergo laparoscopic sleeve gastrectomy (n = 107) or laparoscopic Roux-en-Y gastric bypass (n = 110). The primary end point was weight loss, expressed as percentage excess body mass index (BMI) loss. Exploratory end points were changes in comorbidities and adverse events. Among the 217 patients (mean age, 45.5 years; 72% women; mean BMI, 43.9) 205 (94.5%) completed the trial. Excess BMI loss was not significantly different at 5 years: for sleeve gastrectomy, 61.1%, vs Roux-en-Y gastric bypass, 68.3% (absolute difference, -7.18%; 95% CI, -14.30% to -0.06%; P = .22 after adjustment for multiple comparisons). Gastric reflux remission was observed more frequently after Roux-en-Y gastric bypass (60.4%) than after sleeve gastrectomy (25.0%). Gastric reflux worsened (more symptoms or increase in therapy) more often after sleeve gastrectomy (31.8%) than after Roux-en-Y gastric bypass (6.3%). The number of patients with reoperations or interventions was 16/101 (15.8%) after sleeve gastrectomy and 23/104 (22.1%) after Roux-en-Y gastric bypass. Among patients with morbid obesity, there was no significant difference in excess BMI loss between laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass at 5 years of follow-up after surgery. clinicaltrials.gov Identifier: NCT00356213.

Analysis of Turbofan Design Options for an Advanced Single-Aisle Transport Aircraft

NASA Technical Reports Server (NTRS)

Guynn, Mark D.; Berton, Jeffrey J.; Fisher, Kenneth L.; Haller, William J.; Tong, Michael T.; Thurman, Douglas R.

2009-01-01

The desire for higher engine efficiency has resulted in the evolution of aircraft gas turbine engines from turbojets, to low bypass ratio, first generation turbofans, to today's high bypass ratio turbofans. It is possible that future designs will continue this trend, leading to very-high or ultra-high bypass ratio (UHB) engines. Although increased bypass ratio has clear benefits in terms of propulsion system metrics such as specific fuel consumption, these benefits may not translate into aircraft system level benefits due to integration penalties. In this study, the design trade space for advanced turbofan engines applied to a single-aisle transport (737/A320 class aircraft) is explored. The benefits of increased bypass ratio and associated enabling technologies such as geared fan drive are found to depend on the primary metrics of interest. For example, bypass ratios at which fuel consumption is minimized may not require geared fan technology. However, geared fan drive does enable higher bypass ratio designs which result in lower noise. Regardless of the engine architecture chosen, the results of this study indicate the potential for the advanced aircraft to realize substantial improvements in fuel efficiency, emissions, and noise compared to the current vehicles in this size class.

Intraoperative IR imaging in the cardiac operating room

NASA Astrophysics Data System (ADS)

Szabo, Tamas; Fazekas, Levente; Horkay, Ferenc; Geller, Laslu; Gyongy, Tibor; Juhasz-Nagy, Alexander

1999-07-01

The high blood flow rate and the considerable metabolic activity render the myocardium a possible candidate for IR imaging. The study was aimed to test cardiothermography in evaluating arterial bypass graft patency and in assessing myocardial protection during open-heart surgery. Ten patients underwent arterial bypass grafting. Thermograms were obtained immediately before and after opening the grafts. As the bypasses were opened in hypothermia the warmer blood coming from the extracorporeal circulation readily delineated graft and coronary anatomy. By the end of the 5 min observation period, the revascularized area exhibited a temperature increase of 5.9 +/- 0.7 degrees C. The affectivity of antegrade cardioplegia was monitored in 38 patients undergoing either valve implantations or aorto- coronary bypass surgery. Thermographic imags were taken after sternotomy, before aortic cross-clamping and after administrating the 4 degrees C cardioplegic solution. Most of the patients displayed adequate myocardial cooling, moreover the bypass-group exhibited a more profound temperature-decrease. In conclusion, cardiothermography can visualize arterial grafts, recipient coronaries and collaterals seconds after opening by bypass, thus it properly evaluated arterial bypass graft patency. The obtained images could easily be analyzed for qualitative flow- and quantitative temperature changes. Myocardial protection could also be safely assessed with thermography.

Three trocar laparoscopic Roux-en-y gastric bypass: a novel technique en route to the single-incision laparoscopic approach.

PubMed

Saber, Alan A; Elgamal, Mohamed H; El-Ghazaly, Tarek H; Elian, Alain R; Dewoolkar, Aditya V; Akl, Abir Hassan

2010-01-01

Laparoscopic Roux-en-Y gastric bypass is the gold standard bariatric procedure. Typically, the procedure necessitates five to seven small skin incisions for trocar placement. The senior author (AA Saber) has developed a three-trocar approach for laparoscopic Roux-en-Y gastric bypass. Sixteen patients underwent triple-incision laparoscopic Roux-en-Y gastric bypass between May 2009 and August 2009. The same surgeon performed all surgical interventions. The umbilicus was the main point of entry for all patients and the same operative technique and perioperative protocol were used in all patients. A total of sixteen triple-incision laparoscopic Roux-en-Y gastric bypasses were performed. The procedures were successfully performed in all patients. Mean operating time was 145.4 min. None of the patients required conversion to an open procedure. There were no mortalities or post-operative technical complications noted during the immediate post-operative period. Three trocar laparoscopic Roux-en-Y gastric bypass is safe, technically feasible and reproducible. This technique may be considered a "precursor" to single-incision laparoscopic Roux-en-Y gastric bypass. Copyright 2009 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Spiritual Bypass: A Preliminary Investigation

ERIC Educational Resources Information Center

Cashwell, Craig S.; Glosoff, Harriet L.; Hammond, Cheree

2010-01-01

The phenomenon of spiritual bypass has received limited attention in the transpersonal psychology and counseling literature and has not been subjected to empirical inquiry. This study examines the phenomenon of spiritual bypass by considering how spirituality, mindfulness, alexithymia (emotional restrictiveness), and narcissism work together to…

Idle speed and fuel vapor recovery control system

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

Orzel, D.V.

1993-06-01

A method for controlling idling speed of an engine via bypass throttle connected in parallel to a primary engine throttle and for controlling purge flow through a vapor recovery system into an air/fuel intake of the engine is described, comprising the steps of: positioning the bypass throttle to decrease any difference between a desired engine idle speed and actual engine idle speed; and decreasing the purge flow when said bypass throttle position is less than a preselected fraction of a maximum bypass throttle position.

Prolonged partial cardiopulmonary bypass in rats.

PubMed

Alexander, B; Al Ani, H R

1983-07-01

Membrane oxygenators have been shown to be atraumatic during cardiopulmonary bypass. A novel design for a membrane tubing oxygenator originated in this laboratory was used for prolonged partial supportive cardiopulmonary bypass in lambs and displayed excellent biocompatability characteristics. This was miniaturized, to result in a prime volume of 12 ml, in order to investigate the feasibility of prolonged partial supportive cardiopulmonary bypass in rats. The performance of this miniaturized circuit over perfusion periods up to 6 hr is described, with particular reference to hematological changes.

Neurologic complications after off-pump coronary artery bypass grafting with and without aortic manipulation: meta-analysis of 11,398 cases from 8 studies.

PubMed

Misfeld, Martin; Brereton, R John L; Sweetman, Elizabeth A; Doig, Gordon S

2011-08-01

Neurologic complications after coronary artery bypass grafting remain a concern. Off-pump coronary artery bypass grafting is a surgical strategy proposed to decrease this risk. Use of an off-pump anaortic technique, which leaves the ascending aorta untouched, may result in further reductions. This systematic review of all published evidence compares neurologic complications after anaortic off-pump coronary artery bypass grafting versus that with aortic manipulation. PubMed and Embase were searched up to August 2008. Experts were contacted, and reference lists of retrieved articles were hand searched. The search process was not limited to English-language sources. Observational studies comparing standard off-pump coronary artery bypass grafting technique with anaortic technique were eligible for inclusion if they reported neurologic complications (stroke and transient ischemic attack). Meta-analysis was conducted to assess differences between groups with regard to neurologic complications. Electronic search identified 1428 abstracts, which resulted in retrieval and detailed review of 331 full-text articles. Eight observational studies reported neurologic complications in 5619 anaortic off-pump coronary artery bypass grafting cases and 5779 cases with aortic manipulation. Postsurgical neurologic complications were significantly lower in anaortic off-pump coronary artery bypass grafting cases (odds ratio, 0.46; 95% confidence interval, 0.29-0.72; I(2) = 0.8%; P = .0008). Avoidance of aortic manipulation during off-pump coronary artery bypass grafting decreases neurologic complications relative to standard technique in which the ascending aorta is manipulated. In patients at high risk for stroke or transient ischemic attack, we recommend avoidance of aortic manipulation during off-pump coronary artery bypass grafting. Copyright © 2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

A geographic information system analysis of the impact of a statewide acute stroke emergency medical services routing protocol on community hospital bypass.

PubMed

Asimos, Andrew W; Ward, Shana; Brice, Jane H; Enright, Dianne; Rosamond, Wayne D; Goldstein, Larry B; Studnek, Jonathan

2014-01-01

Our goal was to determine if a statewide Emergency Medical Services (EMSs) Stroke Triage and Destination Plan (STDP), specifying bypass of hospitals unable to routinely treat stroke patients with thrombolytics (community hospitals), changed bypass frequency of those hospitals. Using a statewide EMS database, we identified stroke patients eligible for community hospital bypass and compared bypass frequency 1-year before and after STDP implementation. Symptom onset time was missing for 48% of pre-STDP (n = 2385) and 29% of post-STDP (n = 1612) cases. Of the remaining cases with geocodable scene addresses, 58% (1301) in the pre-STDP group and 61% (2,078) in the post-STDP group were ineligible for bypass, because a community hospital was not the closest hospital to the stroke event location. Because of missing data records for some EMS agencies in 1 or both study periods, we included EMS agencies from only 49 of 100 North Carolina counties in our analysis. Additionally, we found conflicting hospital classifications by different EMS agencies for 35% of all hospitals (n = 38 of 108). Given these limitations, we found similar community hospital bypass rates before and after STDP implementation (64%, n = 332 of 520 vs. 63%, n = 345 of 552; P = .65). Missing symptom duration time and data records in our state's EMS data system, along with conflicting hospital classifications between EMS agencies limit the ability to study statewide stroke routing protocols. Bypass policies may apply to a minority of patients because a community hospital is not the closest hospital to most stroke events. Given these limitations, we found no difference in community hospital bypass rates after implementation of the STDP. Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Hemodynamic effect of bypass geometry on intracranial aneurysm: A numerical investigation.

PubMed

Kurşun, Burak; Uğur, Levent; Keskin, Gökhan

2018-05-01

Hemodynamic analyzes are used in the clinical investigation and treatment of cardiovascular diseases. In the present study, the effect of bypass geometry on intracranial aneurysm hemodynamics was investigated numerically. Pressure, wall shear stress (WSS) and velocity distribution causing the aneurysm to grow and rupture were investigated and the best conditions were tried to be determined in case of bypassing between basilar (BA) and left/right posterior arteries (LPCA/RPCA) for different values of parameters. The finite volume method was used for numerical solutions and calculations were performed with the ANSYS-Fluent software. The SIMPLE algorithm was used to solve the discretized conservation equations. Second Order Upwind method was preferred for finding intermediate point values in the computational domain. As the blood flow velocity changes with time, the blood viscosity value also changes. For this reason, the Carreu model was used in determining the viscosity depending on the velocity. Numerical study results showed that when bypassed, pressure and wall shear stresses reduced in the range of 40-70% in the aneurysm. Numerical results obtained are presented in graphs including the variation of pressure, wall shear stress and velocity streamlines in the aneurysm. Considering the numerical results for all parameter values, it is seen that the most important factors affecting the pressure and WSS values in bypassing are the bypass position on the basilar artery (L b ) and the diameter of the bypass vessel (d). Pressure and wall shear stress reduced in the range of 40-70% in the aneurysm in the case of bypass for all parameters. This demonstrates that pressure and WSS values can be greatly reduced in aneurysm treatment by bypassing in cases where clipping or coil embolization methods can not be applied. Copyright © 2018 Elsevier B.V. All rights reserved.

High-flow bypass with radial artery graft followed by internal carotid artery ligation for large or giant aneurysms of cavernous or cervical portion: clinical results and cognitive performance.

PubMed

Ono, Hideaki; Inoue, Tomohiro; Tanishima, Takeo; Tamura, Akira; Saito, Isamu; Saito, Nobuhito

2018-04-01

High-flow bypass followed by ligation of the internal carotid artery (ICA) is an effective treatment, but the impact of abrupt occlusion of the ICA is unpredictable, especially on postoperative cognitive function. The present study evaluated the clinical results as well as cognitive performances after high-flow bypass using radial artery graft (RAG) with supportive superficial temporal artery (STA)-middle cerebral artery (MCA) bypass, followed by ICA ligation. Ten consecutive patients underwent high-flow bypass surgery for large or giant ICA aneurysms of cavernous or cervical portion. Demographics, clinical information, magnetic resonance (MR) imaging, computed tomography, digital subtraction angiography (DSA), intraoperative somatosensory evoked potentials, neuropsychological examinations including the Wechsler Adult Intelligence Scale-Third Edition and the Wechsler Memory Scale-Revised (WMS-R), and follow-up data were analyzed. The aneurysm was located on the cavernous segment in eight cases and cervical segment in two cases, and mean aneurysm size was 27.9 mm. Postoperative DSA demonstrated robust bypass flow from the external carotid artery to MCA via the RAG, and no anterograde flow into the aneurysm. No patient showed new symptoms after the operation. Follow-up clinical study and MR imaging were performed in nine patients and showed no additional ischemic lesion compared with preoperative imaging. Seven patients completed neuropsychological examinations before and after surgery. All postoperative scores except WMS-R composite memory score slightly improved. High-flow bypass followed by ICA ligation can achieve good clinical outcomes. Successful high-flow bypass using RAG with supportive STA-MCA bypass and ICA ligation does not adversely affect postoperative cognitive function.

In-hospital mortality and morbidity after robotic coronary artery surgery.

PubMed

Cavallaro, Paul; Rhee, Amanda J; Chiang, Yuting; Itagaki, Shinobu; Seigerman, Matthew; Chikwe, Joanna

2015-02-01

The objective of this study was to assess the impact of robotic approaches on outcomes of coronary bypass surgery. Retrospective national database analysis. United States hospitals. A weighted sample of 484,128 patients undergoing isolated coronary artery surgery identified from the Nationwide Inpatient Sample from 2008 through 2010. Robotically assisted coronary artery bypass surgery versus conventional bypass surgery. Robotic approaches were used in 2,582 patients (0.4%). Patients undergoing robotic surgery were less likely to be female (odds ratio [OR] 0.71, 95% confidence interval [CI] 0.57-0.87), present with acute myocardial infarction (OR 0.53, 95% CI 0.38-0.73), or have cerebrovascular disease (OR 0.41, 95% CI 0.23-0.71) compared to patients undergoing conventional surgery. In 59% of robotic cases, a single bypass was performed, and 2 bypasses were performed in 25% of cases. After adjusting for comorbidity, reduced postoperative stroke (0.0% v 1.5%, p = 0.045) and transfusion (13.5% v 24.4%, p = 0.001) rates were observed in patients who underwent robotic single-bypass surgery compared to conventional surgery. In patients undergoing multiple bypass grafts, higher mortality (1.1% v 0.5%), and cardiovascular complications (12.2% v 10.6%) were observed when robotic assistance was used, but the differences were not statistically significant (p = 0.5). The mean number of robotic cases carried out annually at institutions sampled was 6. Robotic assistance is associated with lower rates of postoperative complications in highly selected patients undergoing single coronary artery bypass surgery, but the benefits of this approach are reduced in patients who require multiple coronary artery bypass grafts. Copyright © 2014 Elsevier Inc. All rights reserved.

Stress analysis method for clearance-fit joints with bearing-bypass loads

NASA Technical Reports Server (NTRS)

Naik, R. A.; Crews, J. H., Jr.

1989-01-01

Within a multi-fastener joint, fastener holes may be subjected to the combined effects of bearing loads and loads that bypass the hole to be reacted elsewhere in the joint. The analysis of a joint subjected to search combined bearing and bypass loads is complicated by the usual clearance between the hole and the fastener. A simple analysis method for such clearance-fit joints subjected to bearing-bypass loading has been developed in the present study. It uses an inverse formulation with a linear elastic finite-element analysis. Conditions along the bolt-hole contact arc are specified by displacement constraint equations. The present method is simple to apply and can be implemented with most general purpose finite-element programs since it does not use complicated iterative-incremental procedures. The method was used to study the effects of bearing-bypass loading on bolt-hole contact angles and local stresses. In this study, a rigid, frictionless bolt was used with a plate having the properties of a quasi-isotropic graphite/epoxy laminate. Results showed that the contact angle as well as the peak stresses around the hole and their locations were strongly influenced by the ratio of bearing and bypass loads. For single contact, tension and compression bearing-bypass loading had opposite effects on the contact angle. For some compressive bearing-bypass loads, the hole tended to close on the fastener leading to dual contact. It was shown that dual contact reduces the stress concentration at the fastener and would, therefore, increase joint strength in compression. The results illustrate the general importance of accounting for bolt-hole clearance and contact to accurately compute local bolt-hole stresses for combined bearings and bypass loading.

Increased Postprandial Energy Expenditure May Explain Superior Long Term Weight Loss after Roux-en-Y Gastric Bypass Compared to Vertical Banded Gastroplasty

PubMed Central

Werling, Malin; Olbers, Torsten; Fändriks, Lars; Bueter, Marco; Lönroth, Hans; Stenlöf, Kaj; le Roux, Carel W.

2013-01-01

Background and Aims Gastric bypass results in greater weight loss than Vertical banded gastroplasty (VBG), but the underlying mechanisms remain unclear. In addition to effects on energy intake the two bariatric techniques may differentially influence energy expenditure (EE). Gastric bypass in rats increases postprandial EE enough to result in elevated EE over 24 hours. This study aimed to investigate alterations in postprandial EE after gastric bypass and VBG in humans. Methods Fourteen women from a randomized clinical trial between gastric bypass (n = 7) and VBG (n = 7) were included. Nine years postoperatively and at weight stability patients were assessed for body composition and calorie intake. EE was measured using indirect calorimetry in a respiratory chamber over 24 hours and focused on the periods surrounding meals and sleep. Blood samples were analysed for postprandial gut hormone responses. Results Groups did not differ regarding body composition or food intake either preoperatively or at study visit. Gastric bypass patients had higher EE postprandially (p = 0.018) and over 24 hours (p = 0.048) compared to VBG patients. Postprandial peptide YY (PYY) and glucagon like peptide 1 (GLP-1) levels were higher after gastric bypass (both p<0.001). Conclusions Gastric bypass patients have greater meal induced EE and total 24 hours EE compared to VBG patients when assessed 9 years postoperatively. Postprandial satiety gut hormone responses were exaggerated after gastric bypass compared to VBG. Long-term weight loss maintenance may require significant changes in several physiological mechanisms which will be important to understand if non-surgical approaches are to mimic the effects of bariatric surgery. PMID:23573244

The frequency and accuracy of replication past a thymine-thymine cyclobutane dimer are very different in Saccharomyces cerevisiae and Escherichia coli.

PubMed

Gibbs, P E; Kilbey, B J; Banerjee, S K; Lawrence, C W

1993-05-01

We have compared the mutagenic properties of a T-T cyclobutane dimer in baker's yeast, Saccharomyces cerevisiae, with those in Escherichia coli by transforming each of these species with the same single-stranded shuttle vector carrying either the cis-syn or the trans-syn isomer of this UV photoproduct at a unique site. The mutagenic properties investigated were the frequency of replicational bypass of the photoproduct, the error rate of bypass, and the mutation spectrum. In SOS-induced E. coli, the cis-syn dimer was bypassed in approximately 16% of the vector molecules, and 7.6% of the bypass products had targeted mutations. In S. cerevisiae, however, bypass occurred in about 80% of these molecules, and the bypass was at least 19-fold more accurate (approximately 0.4% targeted mutations). Each of these yeast mutations was a single unique event, and none were like those in E. coli, suggesting that in fact the difference in error rate is much greater. Bypass of the trans-syn dimer occurred in about 17% of the vector molecules in both species, but with this isomer the error rate was higher in S. cerevisiae (21 to 36% targeted mutations) than in E. coli (13%). However, the spectra of mutations induced by the latter photoproduct were virtually identical in the two organisms. We conclude that bypass and error frequencies are determined both by the structure of the photoproduct-containing template and by the particular replication proteins concerned but that the types of mutations induced depend predominantly on the structure of the template. Unlike E. coli, bypass in S. cerevisiae did not require UV-induced functions.

Contrast material-enhanced, moving-table MR angiography versus digital subtraction angiography for surveillance of peripheral arterial bypass grafts.

PubMed

Loewe, Christian; Cejna, Manfred; Schoder, Maria; Loewe-Grgurin, Maria; Wolf, Florian; Lammer, Johannes; Thurnher, Siegfried A

2003-09-01

To assess the accuracy of moving-table MR angiography (MRA) in the evaluation of peripheral bypass grafts. There were 39 patients who had had peripheral bypass graft surgery and then subsequently underwent digital subtraction angiography (DSA) and contrast material-enhanced MRA, which was performed with moving-table software on a 1.0-T system before and during administration of 40 mL gadolinium. For evaluation, every bypass graft was divided into three parts and every leg into 14 segments. Disease severity was scored in four categories (0%-29%, 30%-69%, 70%-99%, 100%). Results were compared with those of the DSA. A total of 147 bypass graft segments and 938 vessel segments were classified. In 132 of the assessable 147 bypass segments, disease gradings with both methods were congruent; however, 13 stenoses were misinterpreted by MRA for one grade and two additional lesions by two grades, leading to an accuracy in precise stenoses detection of 89.9%. The sensitivity and specificity values in the detection of bypass graft stenoses >69% (grade 3 + 4 lesions) reached 90.0% and 98.3%, respectively. In 821 of 938 vessel segments the accuracy of MRA in stenoses detection reached 87.5%. The sensitivity and specificity values in the detection of grade 3 + 4 lesions were 95.6% and 94.0% for the native vessels, respectively. Moving-table MRA was as accurate in assessing bypass grafts as it was for the native arteries and showed a great accuracy in stenosis detection compared with DSA. Therefore, MRA is a promising modality for bypass graft surveillance and might be a noninvasive alternative to DSA in this regard.

Effect of Laparoscopic Sleeve Gastrectomy vs Laparoscopic Roux-en-Y Gastric Bypass on Weight Loss at 5 Years Among Patients With Morbid Obesity: The SLEEVEPASS Randomized Clinical Trial.

PubMed

Salminen, Paulina; Helmiö, Mika; Ovaska, Jari; Juuti, Anne; Leivonen, Marja; Peromaa-Haavisto, Pipsa; Hurme, Saija; Soinio, Minna; Nuutila, Pirjo; Victorzon, Mikael

2018-01-16

Laparoscopic sleeve gastrectomy for treatment of morbid obesity has increased substantially despite the lack of long-term results compared with laparoscopic Roux-en-Y gastric bypass. To determine whether laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass are equivalent for weight loss at 5 years in patients with morbid obesity. The Sleeve vs Bypass (SLEEVEPASS) multicenter, multisurgeon, open-label, randomized clinical equivalence trial was conducted from March 2008 until June 2010 in Finland. The trial enrolled 240 morbidly obese patients aged 18 to 60 years, who were randomly assigned to sleeve gastrectomy or gastric bypass with a 5-year follow-up period (last follow-up, October 14, 2015). Laparoscopic sleeve gastrectomy (n = 121) or laparoscopic Roux-en-Y gastric bypass (n = 119). The primary end point was weight loss evaluated by percentage excess weight loss. Prespecified equivalence margins for the clinical significance of weight loss differences between gastric bypass and sleeve gastrectomy were -9% to +9% excess weight loss. Secondary end points included resolution of comorbidities, improvement of quality of life (QOL), all adverse events (overall morbidity), and mortality. Among 240 patients randomized (mean age, 48 [SD, 9] years; mean baseline body mass index, 45.9, [SD, 6.0]; 69.6% women), 80.4% completed the 5-year follow-up. At baseline, 42.1% had type 2 diabetes, 34.6% dyslipidemia, and 70.8% hypertension. The estimated mean percentage excess weight loss at 5 years was 49% (95% CI, 45%-52%) after sleeve gastrectomy and 57% (95% CI, 53%-61%) after gastric bypass (difference, 8.2 percentage units [95% CI, 3.2%-13.2%], higher in the gastric bypass group) and did not meet criteria for equivalence. Complete or partial remission of type 2 diabetes was seen in 37% (n = 15/41) after sleeve gastrectomy and in 45% (n = 18/40) after gastric bypass (P > .99). Medication for dyslipidemia was discontinued in 47% (n = 14/30) after sleeve gastrectomy and 60% (n = 24/40) after gastric bypass (P = .15) and for hypertension in 29% (n = 20/68) and 51% (n = 37/73) (P = .02), respectively. There was no statistically significant difference in QOL between groups (P = .85) and no treatment-related mortality. At 5 years the overall morbidity rate was 19% (n = 23) for sleeve gastrectomy and 26% (n = 31) for gastric bypass (P = .19). Among patients with morbid obesity, use of laparoscopic sleeve gastrectomy compared with use of laparoscopic Roux-en-Y gastric bypass did not meet criteria for equivalence in terms of percentage excess weight loss at 5 years. Although gastric bypass compared with sleeve gastrectomy was associated with greater percentage excess weight loss at 5 years, the difference was not statistically significant, based on the prespecified equivalence margins. clinicaltrials.gov Identifier: NCT00793143.

Bypass Transitional Flow Calculations Using a Navier-Stokes Solver and Two-Equation Models

NASA Technical Reports Server (NTRS)

Liuo, William W.; Shih, Tsan-Hsing; Povinelli, L. A. (Technical Monitor)

2000-01-01

Bypass transitional flows over a flat plate were simulated using a Navier-Stokes solver and two equation models. A new model for the bypass transition, which occurs in cases with high free stream turbulence intensity (TI), is described. The new transition model is developed by including an intermittency correction function to an existing two-equation turbulence model. The advantages of using Navier-Stokes equations, as opposed to boundary-layer equations, in bypass transition simulations are also illustrated. The results for two test flows over a flat plate with different levels of free stream turbulence intensity are reported. Comparisons with the experimental measurements show that the new model can capture very well both the onset and the length of bypass transition.

Parameterization of a Conventional and Regenerated UHB Turbofan

NASA Astrophysics Data System (ADS)

Oliveira, Fábio; Brójo, Francisco

2015-09-01

The attempt to improve aircraft engines efficiency resulted in the evolution from turbojets to the first generation low bypass ratio turbofans. Today, high bypass ratio turbofans are the most traditional type of engine in commercial aviation. Following many years of technological developments and improvements, this type of engine has proved to be the most reliable facing the commercial aviation requirements. In search of more efficiency, the engine manufacturers tend to increase the bypass ratio leading to ultra-high bypass ratio (UHB) engines. Increased bypass ratio has clear benefits in terms of propulsion system like reducing the specific fuel consumption. This study is aimed at a parametric analysis of a UHB turbofan engine focused on short haul flights. Two cycle configurations (conventional and regenerated) were studied, and estimated values of their specific fuel consumption (TSFC) and specific thrust (Fs) were determined. Results demonstrate that the regenerated cycle may contribute towards a more economic and friendly aero engines in a higher range of bypass ratio.

Bypass of a Nick by the Replisome of Bacteriophage T7*

PubMed Central

Zhu, Bin; Lee, Seung-Joo; Richardson, Charles C.

2011-01-01

DNA polymerase and DNA helicase are essential components of DNA replication. The helicase unwinds duplex DNA to provide single-stranded templates for DNA synthesis by the DNA polymerase. In bacteriophage T7, movement of either the DNA helicase or the DNA polymerase alone terminates upon encountering a nick in duplex DNA. Using a minicircular DNA, we show that the helicase·polymerase complex can bypass a nick, albeit at reduced efficiency of 7%, on the non-template strand to continue rolling circle DNA synthesis. A gap in the non-template strand cannot be bypassed. The efficiency of bypass synthesis depends on the DNA sequence downstream of the nick. A nick on the template strand cannot be bypassed. Addition of T7 single-stranded DNA-binding protein to the complex stimulates nick bypass 2-fold. We propose that the association of helicase with the polymerase prevents dissociation of the helicase upon encountering a nick, allowing the helicase to continue unwinding of the duplex downstream of the nick. PMID:21701044

Bypass of a nick by the replisome of bacteriophage T7.

PubMed

Zhu, Bin; Lee, Seung-Joo; Richardson, Charles C

2011-08-12

DNA polymerase and DNA helicase are essential components of DNA replication. The helicase unwinds duplex DNA to provide single-stranded templates for DNA synthesis by the DNA polymerase. In bacteriophage T7, movement of either the DNA helicase or the DNA polymerase alone terminates upon encountering a nick in duplex DNA. Using a minicircular DNA, we show that the helicase · polymerase complex can bypass a nick, albeit at reduced efficiency of 7%, on the non-template strand to continue rolling circle DNA synthesis. A gap in the non-template strand cannot be bypassed. The efficiency of bypass synthesis depends on the DNA sequence downstream of the nick. A nick on the template strand cannot be bypassed. Addition of T7 single-stranded DNA-binding protein to the complex stimulates nick bypass 2-fold. We propose that the association of helicase with the polymerase prevents dissociation of the helicase upon encountering a nick, allowing the helicase to continue unwinding of the duplex downstream of the nick.

Enteroscopy and radiology for the management of celiac disease complications: Time for a pragmatic roadmap.

PubMed

Branchi, Federica; Locatelli, Martina; Tomba, Carolina; Conte, Dario; Ferretti, Francesca; Elli, Luca

2016-06-01

Celiac disease is the most common autoimmune enteropathy in Western countries, and is usually associated with a good response to the gluten free diet and an excellent prognosis. However, a minority of patients develop complications of the disease, such as refractory celiac disease, ulcerative jejunoileitis and neoplastic complications such as adenocarcinoma of the small bowel and enteropathy associated T cell lymphoma. Neoplastic complications described in association with celiac disease have a high mortality rate, due to their aggressive behavior and to the usual advanced stage at the time of diagnosis. In recent years, the detection of small bowel lesions has dramatically improved thank to the availability of highly performing radiologic and endoscopic techniques. The diagnostic delay of malignant complications in patients with celiac disease may be improved by establishing a pragmatic flowchart for the identification and follow up of "at risk" patients. We performed a comprehensive review of the articles published on this issue in order to promote a roadmap to be applied when facing with celiac patients with suspected small bowel complications. Copyright © 2016 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Pre-test CFD Calculations for a Bypass Flow Standard Problem

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

Rich Johnson

The bypass flow in a prismatic high temperature gas-cooled reactor (HTGR) is the flow that occurs between adjacent graphite blocks. Gaps exist between blocks due to variances in their manufacture and installation and because of the expansion and shrinkage of the blocks from heating and irradiation. Although the temperature of fuel compacts and graphite is sensitive to the presence of bypass flow, there is great uncertainty in the level and effects of the bypass flow. The Next Generation Nuclear Plant (NGNP) program at the Idaho National Laboratory has undertaken to produce experimental data of isothermal bypass flow between three adjacentmore » graphite blocks. These data are intended to provide validation for computational fluid dynamic (CFD) analyses of the bypass flow. Such validation data sets are called Standard Problems in the nuclear safety analysis field. Details of the experimental apparatus as well as several pre-test calculations of the bypass flow are provided. Pre-test calculations are useful in examining the nature of the flow and to see if there are any problems associated with the flow and its measurement. The apparatus is designed to be able to provide three different gap widths in the vertical direction (the direction of the normal coolant flow) and two gap widths in the horizontal direction. It is expected that the vertical bypass flow will range from laminar to transitional to turbulent flow for the different gap widths that will be available.« less

Endovascular Treatments in Combination with Extracranial-Intracranial Bypass for Complex Intracranial Aneurysms.

PubMed

Sato, Kenichi; Endo, Hidenori; Fujimura, Miki; Endo, Toshiki; Matsumoto, Yasushi; Shimizu, Hiroaki; Tominaga, Teiji

2018-05-01

Although most intracranial aneurysms can be treated with microsurgery or endovascular procedure alone, a subset of aneurysms may require a combined approach. The purpose of this study was to assess the efficacy of endovascular interventions combined with bypass surgery for the treatment of complex intracranial aneurysms. We retrospectively reviewed medical records from a prospectively maintained patient database to identify patients who underwent endovascular treatment of an intracranial aneurysm at our institutes between 2007 and 2017. We recruited patients who received a preplanned combination of endovascular treatment and extracranial-intracranial bypass surgery. Forty-four patients (44 aneurysms) were treated with a combined approach. Twenty-four patients presented with subarachnoid hemorrhage. Treatment strategies included endovascular parent artery occlusion with the bypass surgery to restore cerebral blood flow (n = 12), endovascular trapping with bypass surgery to isolate incorporated branches (n = 12), and intra-aneurysmal coil embolization with bypass surgery to isolate incorporated branches (n = 20). During a mean period of 35.6 months, follow-up catheter angiography was performed in 35 of 44 patients (79.5%) and demonstrated complete aneurysm obliteration in 29 patients (82.9%) and bypass patency in 33 (94.3%). The postoperative aneurysm-related mortality and morbidity rates were 6.8% and 13.6%, respectively. Combined endovascular and surgical bypass procedures are useful for the treatment of complex intracranial aneurysms when conventional surgical or endovascular techniques are not feasible and show acceptable rates of morbidity and mortality. Copyright © 2018 Elsevier Inc. All rights reserved.

Forensic investigation of concrete pavement : U.S. 460, Appomattox Bypass.

DOT National Transportation Integrated Search

2005-01-01

This report describes the investigation of structural failure in a section of the Appomattox Bypass along U.S. 460 in the town of Appomattox, Virginia. The bypass is a four-lane divided highway. The section that was investigated is an 11-year-old sec...

Coronary bypass flow during use of intraaortic balloon pumping and left ventricular assist device.

PubMed

Tedoriya, T; Kawasuji, M; Sakakibara, N; Takemura, H; Watanabe, Y; Hetzer, R

1998-08-01

Intraaortic balloon pumping (IABP) and left ventricular assist device (LVAD) are used for left ventricular support when low cardiac output occurs after a coronary bypass operation for serious coronary artery disease. There are hemodynamic differences in blood flow in various kinds of coronary artery bypass grafts, caused by their inherent physiologic characteristics. The hemodynamic effects of left ventricular assistance with IABP and LVAD on blood flow through various coronary artery bypass grafts were investigated. An ascending aorta-coronary bypass graft (ACB), an internal thoracic artery, and a descending aorta-coronary bypass graft were anastomosed to the left anterior descending coronary artery in a canine model. In this experimental model, the blood flow to the same coronary bed in the three types of grafts could be evaluated. Blood flow in the left anterior descending coronary artery through the three types of coronary bypass grafts was studied in this model during or in the absence of ventricular assistance. In the control study, the systolic blood flow did not differ among the three types of grafts, but the diastolic flow decreased in the following order: with the ACB, the internal thoracic artery, and the descending aorta-coronary bypass graft. The systolic flow during IABP and LVAD was similar to the control flows. Use of IABP increased the diastolic flow by 75.3%+/-12.4% of the control value in the ACB, 37.9%+/-25.0% in the internal thoracic artery, and 21.2%+/-11.4% in the descending aorta-coronary bypass graft. The LVAD increased the diastolic flow by 97.7%+/-18.7% of the control value in the ACB, 64.5%+/-25.7% in the internal thoracic artery, and 63.0%+/-27.9% in the descending aorta-coronary bypass graft. The diastolic blood flows in the left anterior descending coronary artery and the three types of grafts were significantly greater with IABP than the control values, and significantly greater with LVAD than with IABP and the control values. The degrees of increase of diastolic flows in the left anterior descending coronary artery and the ACB with IABP and LVAD were significantly greater than in the arterial grafts (p < 0.01). The diastolic flows in the internal thoracic artery and descending aorta-coronary bypass graft increased less than in the native left anterior descending coronary artery and ACB during left ventricular assistance, particularly with IABP. It is important for the selection of tactics for the management of catastrophic status after coronary bypass grafting to consider the hemodynamic characteristics of the graft.

Roux-en-Y Gastric Bypass Operation in Rats

PubMed Central

Bueter, Marco; Abegg, Kathrin; Seyfried, Florian; Lutz, Thomas A.; le Roux, Carel W.

2012-01-01

Currently, the most effective therapy for the treatment of morbid obesity to induce significant and maintained body weight loss with a proven mortality benefit is bariatric surgery1,2. Consequently, there has been a steady rise in the number of bariatric operations done worldwide in recent years with the Roux-en-Y gastric bypass (gastric bypass) being the most commonly performed operation3. Against this background, it is important to understand the physiological mechanisms by which gastric bypass induces and maintains body weight loss. These mechanisms are yet not fully understood, but may include reduced hunger and increased satiation4,5, increased energy expenditure6,7, altered preference for food high in fat and sugar8,9, altered salt and water handling of the kidney10 as well as alterations in gut microbiota11. Such changes seen after gastric bypass may at least partly stem from how the surgery alters the hormonal milieu because gastric bypass increases the postprandial release of peptide-YY (PYY) and glucagon-like-peptide-1 (GLP-1), hormones that are released by the gut in the presence of nutrients and that reduce eating12. During the last two decades numerous studies using rats have been carried out to further investigate physiological changes after gastric bypass. The gastric bypass rat model has proven to be a valuable experimental tool not least as it closely mimics the time profile and magnitude of human weight loss, but also allows researchers to control and manipulate critical anatomic and physiologic factors including the use of appropriate controls. Consequently, there is a wide array of rat gastric bypass models available in the literature reviewed elsewhere in more detail 13-15. The description of the exact surgical technique of these models varies widely and differs e.g. in terms of pouch size, limb lengths, and the preservation of the vagal nerve. If reported, mortality rates seem to range from 0 to 35%15. Furthermore, surgery has been carried out almost exclusively in male rats of different strains and ages. Pre- and postoperative diets also varied significantly. Technical and experimental variations in published gastric bypass rat models complicate the comparison and identification of potential physiological mechanisms involved in gastric bypass. There is no clear evidence that any of these models is superior, but there is an emerging need for standardization of the procedure to achieve consistent and comparable data. This article therefore aims to summarize and discuss technical and experimental details of our previously validated and published gastric bypass rat model. PMID:22710348

Roux-en-Y gastric bypass operation in rats.

PubMed

Bueter, Marco; Abegg, Kathrin; Seyfried, Florian; Lutz, Thomas A; le Roux, Carel W

2012-06-11

Currently, the most effective therapy for the treatment of morbid obesity to induce significant and maintained body weight loss with a proven mortality benefit is bariatric surgery. Consequently, there has been a steady rise in the number of bariatric operations done worldwide in recent years with the Roux-en-Y gastric bypass (gastric bypass) being the most commonly performed operation. Against this background, it is important to understand the physiological mechanisms by which gastric bypass induces and maintains body weight loss. These mechanisms are yet not fully understood, but may include reduced hunger and increased satiation, increased energy expenditure, altered preference for food high in fat and sugar, altered salt and water handling of the kidney as well as alterations in gut microbiota. Such changes seen after gastric bypass may at least partly stem from how the surgery alters the hormonal milieu because gastric bypass increases the postprandial release of peptide-YY (PYY) and glucagon-like-peptide-1 (GLP-1), hormones that are released by the gut in the presence of nutrients and that reduce eating. During the last two decades numerous studies using rats have been carried out to further investigate physiological changes after gastric bypass. The gastric bypass rat model has proven to be a valuable experimental tool not least as it closely mimics the time profile and magnitude of human weight loss, but also allows researchers to control and manipulate critical anatomic and physiologic factors including the use of appropriate controls. Consequently, there is a wide array of rat gastric bypass models available in the literature reviewed elsewhere in more detail. The description of the exact surgical technique of these models varies widely and differs e.g. in terms of pouch size, limb lengths, and the preservation of the vagal nerve. If reported, mortality rates seem to range from 0 to 35%. Furthermore, surgery has been carried out almost exclusively in male rats of different strains and ages. Pre- and postoperative diets also varied significantly. Technical and experimental variations in published gastric bypass rat models complicate the comparison and identification of potential physiological mechanisms involved in gastric bypass. There is no clear evidence that any of these models is superior, but there is an emerging need for standardization of the procedure to achieve consistent and comparable data. This article therefore aims to summarize and discuss technical and experimental details of our previously validated and published gastric bypass rat model.

The Straight Path to Healing: Using Motivational Interviewing to Address Spiritual Bypass

ERIC Educational Resources Information Center

Clarke, Philip B.; Giordano, Amanda L.; Cashwell, Craig S.; Lewis, Todd F.

2013-01-01

Spiritual bypass is the avoidance of underlying emotional issues by focusing solely on spiritual beliefs, practices, and experiences. Motivational interviewing (MI) is a client-centered, compassionate approach to effectively addressing resistance among those who present with spiritual bypass. In this article, the authors provide background…

21 CFR 870.4270 - Cardiopulmonary bypass cardiotomy suction line blood filter.

Code of Federal Regulations, 2014 CFR

2014-04-01

... blood filter. 870.4270 Section 870.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Devices § 870.4270 Cardiopulmonary bypass cardiotomy suction line blood filter. (a) Identification. A cardiopulmonary bypass cardiotomy suction line blood filter is a device used as part of a gas exchange (oxygenator...

21 CFR 870.4270 - Cardiopulmonary bypass cardiotomy suction line blood filter.

Code of Federal Regulations, 2010 CFR

2010-04-01

... blood filter. 870.4270 Section 870.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Devices § 870.4270 Cardiopulmonary bypass cardiotomy suction line blood filter. (a) Identification. A cardiopulmonary bypass cardiotomy suction line blood filter is a device used as part of a gas exchange (oxygenator...

21 CFR 870.4270 - Cardiopulmonary bypass cardiotomy suction line blood filter.

Code of Federal Regulations, 2011 CFR

2011-04-01

... blood filter. 870.4270 Section 870.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Devices § 870.4270 Cardiopulmonary bypass cardiotomy suction line blood filter. (a) Identification. A cardiopulmonary bypass cardiotomy suction line blood filter is a device used as part of a gas exchange (oxygenator...

21 CFR 870.4270 - Cardiopulmonary bypass cardiotomy suction line blood filter.

Code of Federal Regulations, 2012 CFR

2012-04-01

... blood filter. 870.4270 Section 870.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Devices § 870.4270 Cardiopulmonary bypass cardiotomy suction line blood filter. (a) Identification. A cardiopulmonary bypass cardiotomy suction line blood filter is a device used as part of a gas exchange (oxygenator...

21 CFR 870.4270 - Cardiopulmonary bypass cardiotomy suction line blood filter.

Code of Federal Regulations, 2013 CFR

2013-04-01

... blood filter. 870.4270 Section 870.4270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Devices § 870.4270 Cardiopulmonary bypass cardiotomy suction line blood filter. (a) Identification. A cardiopulmonary bypass cardiotomy suction line blood filter is a device used as part of a gas exchange (oxygenator...

40 CFR 403.17 - Bypass.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Definitions. (1) Bypass means the intentional diversion of wastestreams from any portion of an Industrial User... applicable Pretreatment Standards or Requirements. An Industrial User may allow any bypass to occur which... paragraphs (c) and (d) of this section. (c) Notice. (1) If an Industrial User knows in advance of the need...

40 CFR 403.17 - Bypass.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Definitions. (1) Bypass means the intentional diversion of wastestreams from any portion of an Industrial User... applicable Pretreatment Standards or Requirements. An Industrial User may allow any bypass to occur which... paragraphs (c) and (d) of this section. (c) Notice. (1) If an Industrial User knows in advance of the need...

40 CFR 403.17 - Bypass.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) Definitions. (1) Bypass means the intentional diversion of wastestreams from any portion of an Industrial User... applicable Pretreatment Standards or Requirements. An Industrial User may allow any bypass to occur which... paragraphs (c) and (d) of this section. (c) Notice. (1) If an Industrial User knows in advance of the need...

40 CFR 403.17 - Bypass.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Definitions. (1) Bypass means the intentional diversion of wastestreams from any portion of an Industrial User... applicable Pretreatment Standards or Requirements. An Industrial User may allow any bypass to occur which... paragraphs (c) and (d) of this section. (c) Notice. (1) If an Industrial User knows in advance of the need...

40 CFR 403.17 - Bypass.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Definitions. (1) Bypass means the intentional diversion of wastestreams from any portion of an Industrial User... applicable Pretreatment Standards or Requirements. An Industrial User may allow any bypass to occur which... paragraphs (c) and (d) of this section. (c) Notice. (1) If an Industrial User knows in advance of the need...

20 CFR 631.18 - Federal by-pass authority.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Federal by-pass authority. 631.18 Section 631.18 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR PROGRAMS UNDER... Secretary's intent to exercise by-pass authority and an opportunity to request and to receive a hearing...

IMPACT ON DISINFECTION AT PEAK FLOWS DURING BLENDING/PARTIAL BYPASSING OF SECONDARY TREATMENT

EPA Science Inventory

A U.S EPA study evaluated the impact on disinfection during peak flows when a portion of the flow to the wastewater treatment plant (WWTP) bypasses secondary treatment prior to disinfection. The practice of bypassing secondary treatment during peak flows, referred to as “blending...

Systems and methods for photovoltaic string protection

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

Krein, Philip T.; Kim, Katherine A.; Pilawa-Podgurski, Robert C. N.

A system and method includes a circuit for protecting a photovoltaic string. A bypass switch connects in parallel to the photovoltaic string and a hot spot protection switch connects in series with the photovoltaic string. A first control signal controls opening and closing of the bypass switch and a second control signal controls opening and closing of the hot spot protection switch. Upon detection of a hot spot condition the first control signal closes the bypass switch and after the bypass switch is closed the second control signal opens the hot spot protection switch.

Environmental Assessment: Johnson County Road F-20 Bypass, Johnson County, Iowa.

DTIC Science & Technology

1986-08-01

D-A184 328 ENVIRONMENTAL ASSESSMENT- JOHNSON COUNTY ROAD F-20 vil BYPASS JOHNSON COUNTY’ IOWA (U) ARMY ENGINEER DISTRICT ROCK ISLAND IL AUG 86...BYPASS JOHNSON COUNTY, IOWA DTIC SELECTEI AUG 24 198D AUGUST 1986 -’"Thn; c>, .. i ’, been p ore i Icr publj rJlxaje aid sale; ii ,,. I distibu on is...2004 19 EPLY TO ATTENTION OP NCRPD-E ENVIRONMENTAL ASSE SSMENT JOHNSON COUNTY ROAD F-20 BYPASS JOHNSON COUNTY, IOWA Acce3siofl For NTIS MR& QUA~rTY

Sodium thiopental and mean arterial pressure during cardiopulmonary bypass.

PubMed

Dabbagh, Ali; Rajaei, Samira; Ahani, Mohammad Reza

2011-06-01

Sodium thiopental is known to have a number of cardiovascular effects, but injection into the cardiopulmonary bypass reservoir has not been studied. The effect of sodium thiopental on mean arterial blood pressure during cardiopulmonary bypass was assessed in 150 patients undergoing elective coronary artery bypass grafting. Sodium thiopental 3 mg · kg(-1) was administered via the cardiopulmonary bypass reservoir. Mean arterial pressure was recorded just before drug administration and at 15-sec intervals up to 120 sec afterwards. Compared to the baseline value, mean arterial pressure was significantly higher at 30, 45, 60, and 75 sec after drug administration, and it was significantly lower at 90, 105, and 120 sec. Sodium thiopental, in addition to its effects on myocardial tissue, acts initially as a potent vasopressor, and shortly after, as a potent vasodilator.

Totally Endoscopic Coronary Artery Bypass for Anomalous Origin of Right Coronary Artery.

PubMed

Kuo, Chia-Cheng; Hsing, Chung-Hsi; Cheng, Bor-Chih

2017-01-01

Anomalous origin of the right coronary artery (ARCA) from the left Valsalva sinus is a rare but known cause of sudden cardiac death. Surgical revascularization techniques include coronary artery bypass grafting, unroofing, and reimplantation. We report 4 patients who underwent robot-assisted totally endoscopic coronary artery bypass (TECAB) for ARCA as an alternative surgical option. In 3 patients, a single aortocoronary saphenous vein bypass was performed, and in 1 patient the right internal mammary artery was used. All grafts are patent as shown by computed tomographic angiography or cardiac catheterization. We claim that totally endoscopic coronary artery bypass is feasible and safe for anomalous origin of the right coronary artery. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

[Pedal bypass using venous allograft].

PubMed

Pluháčková, H; Staffa, R; Konečný, Z; Kříž, Z; Vlachovský, R

Pedal or distal crural bypass surgery for limb salvage is a method with very good long-term results. For patients in whom a suitable autologous venous graft is not available, the use of a venous allograft is an alternative procedure. A 68 years old man with ischaemic disease of lower extremities and gangrene of the left foot was admitted to our Centre in August 2014. He underwent percutaneous transluminal angioplasty of crural arteries of his left lower extremity. This, however, failed to improve peripheral circulation. The patient was then indicated for pedal or distal crural vascular reconstruction. Since no suitable autologous vein was available, distal bypass surgery using a donor graft remained the only option for limb salvage. Amputation of the toes on the left foot due to gangrene was necessary. Subsequently, femoro-pedal bypass to the left common plantar artery was performed using a great saphenous vein allograft. The post-operative course was without complications, the pedal bypass was patent and toe amputation was with good healing. The patient remained in follow-up care. A good outcome of vascular reconstruction with an allograft depends on the availability of a suitable allograft and good patient compliance with post-operative care. In the case presented here, the pedal bypass grafting by means of an allograft helped to save the patients limb. pedal bypass venous allograft limb salvage.

Gastric bypass: why Roux-en-Y? A review of experimental data.

PubMed

Collins, Brendan J; Miyashita, Tomoharu; Schweitzer, Michael; Magnuson, Thomas; Harmon, John W

2007-10-01

To highlight the clinical and experimental rationales that support why the Roux-en-Y limb is an important surgical principle for bariatric gastric bypass. We reviewed PubMed citations for open Roux-en-Y gastric bypass (RYGBP), laparoscopic RYGBP, loop gastric bypass, chronic alkaline reflux gastritis, and duodenoesophageal reflux. We reviewed clinical and experimental articles. Clinical articles included prospective, retrospective, and case series of patients undergoing RYGBP, laparoscopic RYGBP, or loop gastric bypass. Experimental articles that were reviewed included in vivo and in vitro models of chronic duodenoesophageal reflux and its effect on carcinogenesis. No formal data extraction was performed. We reviewed published operative times, lengths of stay, and anastomotic leak rates for laparoscopic RYGBP and loop gastric bypass. For in vivo and in vitro experimental models of duodenoesophageal reflux, we reviewed the kinetics and potential molecular mechanisms of carcinogenesis. Recent data suggest that laparoscopic loop gastric bypass, performed without the creation of a Roux-en-Y gastroenterostomy, is a faster surgical technique that confers similarly robust weight loss compared with RYGBP or laparoscopic RYGBP. In the absence of a Roux limb, the long-term effects of chronic alkaline reflux are unknown. Animal models and in vitro analyses of chronic alkaline reflux suggest a carcinogenic effect.

Role of Structural Asymmetry in Controlling Drop Spacing in Microfluidic Ladder Networks

NASA Astrophysics Data System (ADS)

Wang, William; Maddala, Jeevan; Vanapalli, Siva; Rengasamy, Raghunathan

2012-02-01

Manipulation of drop spacing is crucial to many processes in microfluidic devices including drop coalescence, detection and storage. Microfluidic ladder networks ---where two droplet-carrying parallel channels are connected by narrow bypass channels through which the motion of drops is forbidden---have been proposed as a means to control relative separation between pairs of drops. Prior studies in microfluidic ladder networks with vertical bypasses, which possess fore-aft structural symmetry, have revealed that pairs of drops can only undergo reduction in drop spacing at the ladder exit. We investigate the dynamics of drops in microfluidic ladder networks with both vertical and slanted bypasses. Our analytical results indicate that unlike symmetric ladder networks, structural asymmetry introduced by a single slanted bypass can be used to modulate the relative spacing between drops, enabling them to contract, synchronize, expand or even flip at the ladder exit. Our experiments confirm all the behaviors predicted by theory. Numerical analysis further shows that ladders containing several identical bypasses can only linearly transform the input drop spacing. Finally, we find that ladders with specific combinations of vertical and slanted bypasses can generate non-linear transformation of input drop spacing, despite the absence of drop decision-making events at the bypass junctions.

A personalized medicine approach to the design of dry powder inhalers: Selecting the optimal amount of bypass.

PubMed

Kopsch, Thomas; Murnane, Darragh; Symons, Digby

2017-08-30

In dry powder inhalers (DPIs) the patient's inhalation manoeuvre strongly influences the release of drug. Drug release from a DPI may also be influenced by the size of any air bypass incorporated in the device. If the amount of bypass is high less air flows through the entrainment geometry and the release rate is lower. In this study we propose to reduce the intra- and inter-patient variations of drug release by controlling the amount of air bypass in a DPI. A fast computational method is proposed that can predict how much bypass is needed for a specified drug delivery rate for a particular patient. This method uses a meta-model which was constructed using multiphase computational fluid dynamic (CFD) simulations. The meta-model is applied in an optimization framework to predict the required amount of bypass needed for drug delivery that is similar to a desired target release behaviour. The meta-model was successfully validated by comparing its predictions to results from additional CFD simulations. The optimization framework has been applied to identify the optimal amount of bypass needed for fictitious sample inhalation manoeuvres in order to deliver a target powder release profile for two patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Protein Interactions in T7 DNA Replisome Facilitate DNA Damage Bypass.

PubMed

Zou, Zhenyu; Chen, Ze; Xue, Qizhen; Xu, Ying; Xiong, Jingyuan; Yang, Ping; Le, Shuai; Zhang, Huidong

2018-06-14

DNA replisome inevitably encounters DNA damage during DNA replication. T7 DNA replisome contains DNA polymerase (gp5), the processivity factor thioredoxin (trx), helicase-primase (gp4), and ssDNA binding protein (gp2.5). T7 protein interactions mediate this DNA replication. However, whether the protein interactions could promote DNA damage bypass is still little addressed. In this study, we investigated the strand-displacement DNA synthesis past 8-oxoG or O6-MeG at the synthetic DNA fork by T7 DNA replisome. DNA damage does not obviously affect the binding affinities among helicase, polymerase, and DNA fork. Relative to unmodified G, both 8-oxoG and O6-MeG, as well as GC-rich template sequence clusters, inhibit the strand-displacement DNA synthesis and produce partial extension products. Relative to gp4 ΔC-tail, gp4 promotes the DNA damage bypass. The presence of gp2.5 further promotes this bypass. Thus, the interactions of polymerase with helicase and ssDNA binidng protein faciliate the DNA damage bypass. Similarly, accessory proteins in other complicated DNA replisomes also facilitate the DNA damage bypass. This work provides the novel mechanism information of DNA damage bypass by DNA replisome. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Endothelin and vasopressin influence splanchnic blood flow distribution during and after cardiopulmonary bypass.

PubMed

Bomberg, Hagen; Bierbach, Benjamin; Flache, Stephan; Wagner, Isabell; Gläser, Lena; Groesdonk, Heinrich V; Menger, Michael D; Schäfers, Hans-Joachim

2013-02-01

Gastrointestinal blood flow can be compromised during and after cardiopulmonary bypass. Endothelin has been shown to be involved in the intestinal microcirculatory disturbance of sepsis. The aim of the present study was to analyze the involvement of the endothelin system on intestinal blood flow regulation during cardiopulmonary bypass and the effect of vasopressin given during cardiopulmonary bypass. A total of 24 pigs were studied in 4 groups (n = 6): group I, sham; group II, ischemia/reperfusion with 1 hour of superior mesenteric artery occlusion; group III, cardiopulmonary bypass for 1 hour; and group IV, 1 hour of cardiopulmonary bypass plus vasopressin administration, maintaining the baseline arterial pressure. All the pigs were reperfused for 90 minutes. During the experiment, the hemodynamics and jejunal microcirculation were measured continuously. The jejunal mucosal expression of endothelin-1 and its receptor subtypes A and B were determined using polymerase chain reaction. During cardiopulmonary bypass, superior mesenteric artery flow was preserved but marked jejunal microvascular impairment occurred compared with baseline (mucosal capillary density, 192.2 ± 5.4 vs 150.8 ± 5.1 cm/cm(2); P = .005; tissue blood flow, 501.7 ± 39.3 vs 332.3 ± 27.9 AU; P = .025). The expression of endothelin-1 after cardiopulmonary bypass (3.2 ± 0.4 vs 12.2 ± 0.8 RQ, P = .006) and endothelin subtype A (0.7 ± 0.2 vs 2.4 ± 0.6 RQ; P = .01) was significantly increased compared to the sham group. Vasopressin administration during cardiopulmonary bypass led to normal capillary density (189.9 ± 3.9 vs 178.0 ± 6.3; P = .1) and tissue blood flow (501.7 ± 39.3 vs 494.7 ± 44.4 AU; P = .4) compared with baseline. The expression of endothelin-1 (3.2 ± 0.4 vs 1.8 ± 0.3 RQ; P = .3) and endothelin subtype A (0.7 ± 0.2 vs 0.9 ± 0.2 RQ; P = .5) was not different from the sham group. Cardiopulmonary bypass leads to microvascular impairment of jejunal microcirculation, which is associated with the upregulation of endothelin-1 and endothelin subtype A. The administration of vasopressin minimizes these cardiopulmonary bypass-associated alterations. Copyright © 2013 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

The increased use of computed tomography angiography and magnetic resonance angiography as the sole imaging modalities prior to infrainguinal bypass has had no effect on outcomes.

PubMed

Shue, Bing; Damle, Rachelle N; Flahive, Julie; Kalish, Jeffrey A; Stone, David H; Patel, Virendra I; Schanzer, Andres; Baril, Donald T

2015-08-01

Angiography remains the gold standard imaging modality before infrainguinal bypass. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have emerged as noninvasive alternatives for preoperative imaging. We sought to examine contemporary trends in the utilization of CTA and MRA as isolated imaging modalities before infrainguinal bypass and to compare outcomes following infrainguinal bypass in patients who underwent CTA or MRA versus those who underwent conventional arteriography. Patients undergoing infrainguinal bypass within the Vascular Study Group of New England were identified (2003-2012). Patients were stratified by preoperative imaging modality: CTA/MRA alone or conventional angiography. Trends in utilization of these modalities were examined and demographics of these groups were compared. Primary end points included primary patency, secondary patency, and major adverse limb events (MALE) at 1 year as determined by Kaplan-Meier analysis. Multivariable Cox proportional hazards models were constructed to evaluate the effect of imaging modality on primary patency, secondary patency, and MALE after adjusting for confounders. In 3123 infrainguinal bypasses, CTA/MRA alone was used in 462 cases (15%) and angiography was used in 2661 cases (85%). Use of CTA/MRA alone increased over time, with 52 (11%) bypasses performed between 2003 and 2005, 189 (41%) bypasses performed between 2006 and 2009, and 221 (48%) bypasses performed between 2010 and 2012 (P < 0.001). Patients with CTA/MRA alone, compared with patients with angiography, more frequently underwent bypass for claudication (33% vs. 26%, P = 0.001) or acute limb ischemia (13% vs. 5%, P < 0.0001), more frequently had prosthetic conduits (39% vs. 30%, P = 0.001), and less frequently had tibial/pedal targets (32% vs. 40%, P = 0.002). After adjusting for these and other confounders, multivariable analysis demonstrated that the use of CTA/MRA alone was not associated with a significant difference in 1 year primary patency (hazard ratio [HR] 0.95, 95% confidence interval [CI] 0.78-1.16), secondary patency (HR 1.30, 95% CI 0.99-1.72), or MALE (HR 1.08, 95% CI 0.89-1.32). CTA and MRA are being increasingly used as the sole preoperative imaging modality before infrainguinal bypass. This shift in practice patterns appears to have no measurable effect on outcomes at 1 year. Copyright © 2015 Elsevier Inc. All rights reserved.

Narrowing the gap: early and intermediate outcomes after percutaneous coronary intervention and coronary artery bypass graft procedures in California, 1997 to 2006.

PubMed

Carey, Joseph S; Danielsen, Beate; Milliken, Jeffrey; Li, Zhongmin; Stabile, Bruce E

2009-11-01

Percutaneous coronary intervention is increasingly used to treat multivessel coronary artery disease. Coronary artery bypass graft procedures have decreased, and as a result, percutaneous coronary intervention has increased. The overall impact of this treatment shift is uncertain. We examined the in-hospital mortality and complication rates for these procedures in California using a combined risk model. The confidential dataset of the Office of Statewide Health Planning and Development patient discharge database was queried for 1997 to 2006. A risk model was developed using International Classification of Diseases, Ninth Revision, Clinical Modification procedures and diagnostic codes from the combined pool of isolated coronary artery bypass graft and percutaneous coronary intervention procedures performed during 2005 and 2006. In-hospital mortality was corrected for "same-day" transfers to another health care institution. Early failure rate was defined as in-hospital mortality rate plus reintervention for another percutaneous coronary intervention or cardiac surgery procedure within 90 days. Coronary artery bypass graft volume decreased from 28,495 (1997) to 15,520 (2006), whereas percutaneous coronary intervention volume increased from 38,098 to 53,703. Risk-adjusted mortality rate decreased from 4.7% to 2.1% for coronary artery bypass graft procedures and from 3.4% to 1.9% for percutaneous coronary intervention. Expected mortality rate increased for both procedures. Early failure rate decreased from 13.1% to 8.0% for percutaneous coronary intervention and from 6.5% to 5.4% for coronary artery bypass graft. For the years 2004 and 2005, the risk of recurrent myocardial infarction or need for coronary artery bypass graft during the first postoperative year was 12% for percutaneous coronary intervention and 6% for coronary artery bypass grafts. This study shows that as volume shifted from coronary artery bypass grafts to percutaneous coronary intervention, expected mortality increased for both procedures. Risk-adjusted mortality rate decreased for both procedures, more so for coronary artery bypass grafts, so that corrected in-hospital mortality rates essentially equalized at approximately 2.0% in 2006. The post-procedural risk of reintervention, death, or myocardial infarction within the first year was twice as high for percutaneous coronary intervention as for coronary artery bypass grafts.

Is It Worthwhile Treating Occluded Cold Stored Venous Allografts by Thrombolysis?

PubMed

Balaz, P; Wohlfahrt, P; Rokosny, S; Maly, S; Bjorck, M

2016-09-01

Thrombolysis has been reported to be suboptimal in occluded vein grafts and cryopreserved allografts, and there are no data on the efficacy of thrombolysis in occluded cold stored venous allografts. The aim was to evaluate early outcomes, secondary patency and limb salvage rates of thrombolysed cold stored venous allograft bypasses and to compare the outcomes with thrombolysis of autologous bypasses. This was a single center study of consecutive patients with acute and non-acute limb ischemia between September 1, 2000, and January 1, 2014, with occlusion of cold stored venous allografts, and between January 1, 2012, and January 1, 2014, with occlusion of autologous bypass who received intra-arterial thrombolytic therapy. Sixty-one patients with occlusion of an infrainguinal bypass using a cold stored venous allograft (n = 35) or an autologous bypass (n = 26) underwent percutaneous intra-arterial thrombolytic therapy. The median duration of thrombolysis was 20 h (IQR 18-24) with no difference between the groups (p = .14). The median follow up was 18.5 months (IQR 11.0-52.0). Secondary patency rates of thrombolysed bypass at 6 and 12 months were 44 ± 9% and 32 ± 9% in patients with a venous allograft bypass and 46 ± 10% and 22 ± 8% with an autologous bypass, with no difference between groups (p = .40). Limb salvage rates at 1, 6, and 12 months after thrombolysis in the venous allograft group were 83 ± 7%, 72 ± 8% and 63 ± 9%, and in the autologous group 91 ± 6%, 76 ± 9%, and 65 ± 13%, with no difference between groups (p = .69). Long-term results of thrombolysis of venous allograft bypasses are similar to those of autologous bypasses. Occluded cold stored venous allograft can be successfully re-opened in most cases with a favorable effect on limb salvage. Copyright © 2016 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Can the use of methylprednisolone, vitamin C, or alpha-trinositol prevent cold-induced fluid extravasation during cardiopulmonary bypass in piglets?

PubMed

Farstad, M; Heltne, J K; Rynning, S E; Onarheim, H; Mongstad, A; Eliassen, F; Husby, P

2004-02-01

Hypothermic cardiopulmonary bypass is associated with capillary fluid leakage, resulting in edema and occasionally organ dysfunction. Systemic inflammatory activation is considered responsible. In some studies methylprednisolone has reduced the weight gain during cardiopulmonary bypass. Vitamin C and alpha-trinositol have been demonstrated to reduce the microvascular fluid and protein leakage in thermal injuries. We therefore tested these three agents for the reduction of cold-induced fluid extravasation during cardiopulmonary bypass. A total of 28 piglets were randomly assigned to four groups of 7 each: control group, high-dose vitamin C group, methylprednisolone group, and alpha-trinositol-group. After 1 hour of normothermic cardiopulmonary bypass, hypothermic cardiopulmonary bypass was initiated in all animals and continued to 90 minutes. The fluid level in the extracorporeal circuit reservoir was kept constant at the 400-mL level and used as a fluid gauge. Fluid needs, plasma volume, changes in colloid osmotic pressure in plasma and interstitial fluid, hematocrit, and total water contents in different tissues were recorded, and the protein masses and the fluid extravasation rate were calculated. Hemodilution was about 25% after start of normothermic cardiopulmonary bypass. Cooling did not cause any further changes in hemodilution. During steady-state normothermic cardiopulmonary bypass, the fluid need in all groups was about 0.10 mL/(kg.min), with a 9-fold increase during the first 30 minutes of cooling (P <.001). This increased fluid need was due mainly to increased fluid extravasation from the intravascular to the interstitial space at a mean rate of 0.6 mL/(kg.min) (range 0.5-0.7 mL/[kg.min]; P <.01) and was reflected by increased total water content in most tissues in all groups. The albumin and protein masses remained constant in all groups throughout the study. Pretreatment with methylprednisolone, vitamin C, or alpha-trinositol was unable to prevent the increased fluid extravasation rate during hypothermic cardiopulmonary bypass. These findings, together with the stability of the protein masses throughout the study, support the presence of a noninflammatory mechanism behind the cold-induced fluid leakage seen during cardiopulmonary bypass.

Early superficial temporal artery to middle cerebral artery bypass in acute ischemic stroke.

PubMed

Lee, Sang-Bok; Huh, Pil-Woo; Kim, Dal-Soo; Yoo, Do-Sung; Lee, Tae-Gyu; Cho, Kyoung-Suok

2013-08-01

To evaluate the effects and safety of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis in the early stage after an acute ischemic event and the improvement of present symptoms in patients with intracranial atherosclerotic occlusive disease with stroke/stroke in progress. From 2006 to 2010, 20 patients (15 males and five females) with atherosclerotic cerebrovascular disease were treated with an STA-MCA bypass. All of the patients presented with an acute ischemic stroke or stroke in progress despite maximal medical treatment. The patients underwent an STA-MCA bypass within 7 days from symptom onset. The clinical outcome and hemodynamic study of the 20 patients were preoperatively and postoperatively investigated. A pooled analysis was performed, and the results were compared with those obtained from other delayed STA-MCA bypass studies. Among the 20 patients who underwent an early STA-MCA bypass, fourteen (70%) patients achieved a good functional outcome (mRS 0, n=3; mRS 1, n=9; mRS 2, n=2). Prior to surgery, the mean basal regional cerebral blood flow (rCBF) and cerebrovascular reserve capacity (CVR) in the symptomatic hemisphere were 37.3±4.3 ml/100 g/min and -1.68±2.9%. The mean basal rCBF and CVR had significantly increased postoperatively, and no reperfusion-induced hemorrhage had occurred. In the pooled analysis, no significant differences were observed in the clinical outcome (P=0.328) or in the incidence of postoperative complications (P=0.516) between patients who underwent an early STA-MCA bypass and in patients who underwent a delayed STA-MCA bypass in previous studies. In this study, which consisted of 20 carefully selected patients with acute ischemic stroke, an early STA-MCA bypass was safely and effectively performed, and in some cases, an early STA-MCA bypass resulted in rapid neurological improvement. An early STA-MCA bypass was beneficial in select patients who had acute ischemic stroke with imaging evidence of a small infarction. Copyright © 2012 Elsevier B.V. All rights reserved.

The in situ side-to-side bypass technique: a comprehensive review of the technical characteristics, current anastomosis approaches and surgical experience.

PubMed

Wang, Long; Cai, Li; Qian, Hai; Lawton, Michael T; Shi, Xiang'en

2018-05-02

In situ side-to-side (STS) revascularization is an intracranial-intracranial (IC-IC) bypass technique that is increasingly used to treat complex aneurysms and cerebral ischemia. This sophisticated technique involves connecting two proximal parallel vessels to create an artificial conduit for blood flow. This study aims to provide a detailed description of the configuration of the STS bypass technique and extensive information regarding its technical characteristics, current anastomosis approaches and surgical significance. A literature search was performed using the PubMed, Medline, ScienceDirect, Embase, Wiley Online Library, Cambridge Journals, SAGE Journals, Oxford Journals, Research Gate, and Google Scholar databases. The terms "intracranial-intracranial bypass", "in situ bypass", "communicating bypass" and "STS anastomosis" were searched to identify pertinent articles. Articles involving in situ STS anastomosis combined with other bypass methods were excluded. Computer tablet-drawn illustrations of this technique are provided to enhance comprehension. In total, seventy articles that met our search and inclusion criteria were identified. Overall, the radiographical and clinical outcomes of one-hundred and thirty-two (125 aneurysm and 7 cerebral ischemia) patients who underwent in situ STS revascularization were analyzed. IC-IC bypass in the STS fashion can be a safe and effective strategy for the management of complex intracranial aneurysms and cerebral ischemia and is particularly attractive in rescue, anticipated and troubleshooting cases. Despite its extreme rarity, a de novo aneurysm may be observed following STS anastomosis; thus, long-term follow-up is mandatory. Vascular neurosurgeons should consider including this procedure in their treatment armamentarium. Copyright © 2018. Published by Elsevier Inc.

EC-IC bypass for cavernous carotid aneurysms: An initial experience with twelve patients

PubMed Central

Menon, G.; Jayanand, Sudhir; Krishnakumar, K.; Nair, S.

2014-01-01

Aims: Need for performing a bypass procedure prior to parent artery occlusion in patients with good cerebral vascular reserve is controversial. We analyze our experience of 12 giant internal carotid artery aneurysms treated with extracranial-intracranial (EC-IC) bypass and proximal artery occlusion. Materials and Methods: Retrospective analysis of the case records of all complex carotid aneurysms operated in our institute since January 2009. Results: The study included eleven cavernous carotid aneurysms and one large fusiform cervical carotid aneurysm reaching the skull base. Preoperative assessment of cerebral vascular reserve was limited to Balloon test occlusion with hypotensive challenge. Eleven patients who successfully completed a Balloon test occlusion (BTO) underwent low flow superficial temporal artery to middle cerebral artery (STA-MCA) bypass, while one patient with a failed BTO underwent a high flow bypass using a saphenous vein graft. Parent artery ligation was performed in all patients following the bypass procedure. Check angiogram revealed thrombosis of the aneurysm in all patients with a graft patency rate of 81.8%. We had one operative mortality, probably related to a leak from the anastomotic site. The only patient who had a high flow bypass developed contralateral hemispheric infarcts and remained vegetative. All the other patients had a good recovery and with a Glasgow outcome score of 5 at last follow-up. Conclusion: We feel that combining EC-IC bypass prior to parent vessel occlusion helps in reducing the risk of post operative ischemic complications especially in situations where a complete mandated cerebral blood flow studies are not feasible. PMID:25126123

40 CFR 63.307 - Standards for bypass/bleeder stacks.

Code of Federal Regulations, 2014 CFR

2014-07-01

... National Emission Standards for Coke Oven Batteries § 63.307 Standards for bypass/bleeder stacks. (a)(1.... (2) Coke oven emissions shall not be vented to the atmosphere through bypass/bleeder stacks, except.... (3) The owner or operator of a brownfield coke oven battery or a padup rebuild shall install such a...

40 CFR 63.307 - Standards for bypass/bleeder stacks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... National Emission Standards for Coke Oven Batteries § 63.307 Standards for bypass/bleeder stacks. (a)(1.... (2) Coke oven emissions shall not be vented to the atmosphere through bypass/bleeder stacks, except.... (3) The owner or operator of a brownfield coke oven battery or a padup rebuild shall install such a...

40 CFR 63.307 - Standards for bypass/bleeder stacks.

Code of Federal Regulations, 2012 CFR

2012-07-01

... National Emission Standards for Coke Oven Batteries § 63.307 Standards for bypass/bleeder stacks. (a)(1.... (2) Coke oven emissions shall not be vented to the atmosphere through bypass/bleeder stacks, except.... (3) The owner or operator of a brownfield coke oven battery or a padup rebuild shall install such a...

Bypassing An Open-Circuit Power Cell

NASA Technical Reports Server (NTRS)

Wannemacher, Harry E.

1994-01-01

Collection of bypass circuits enables battery consisting series string of cells to continue to function when one of its cells fails in open-circuit (high-resistance) condition. Basic idea simply to shunt current around defective cell to prevent open circuit from turning off battery altogether. Bypass circuits dissipate little power and are nearly immune to false activation.

Engine Concept Study for an Advanced Single-Aisle Transport

NASA Technical Reports Server (NTRS)

Guynn, Mark D.; Berton, Jeffrey J.; Fisher, Kenneth L.; Haller, William J.; Tong, Michael; Thurman, Douglas R.

2009-01-01

The desire for higher engine efficiency has resulted in the evolution of aircraft gas turbine engines from turbojets, to low bypass ratio, first generation turbofans, to today's high bypass ratio turbofans. Although increased bypass ratio has clear benefits in terms of propulsion system metrics such as specific fuel consumption, these benefits may not translate into aircraft system level benefits due to integration penalties. In this study, the design trade space for advanced turbofan engines applied to a single aisle transport (737/A320 class aircraft) is explored. The benefits of increased bypass ratio and associated enabling technologies such as geared fan drive are found to depend on the primary metrics of interest. For example, bypass ratios at which mission fuel consumption is minimized may not require geared fan technology. However, geared fan drive does enable higher bypass ratio designs which result in lower noise. The results of this study indicate the potential for the advanced aircraft to realize substantial improvements in fuel efficiency, emissions, and noise compared to the current vehicles in this size class.

Bleeding duodenal ulcer after Roux-en-Y gastric bypass surgery: the value of laparoscopic gastroduodenoscopy.

PubMed

Issa, Hussain; Al-Saif, Osama; Al-Momen, Sami; Bseiso, Bahaa; Al-Salem, Ahmed

2010-01-01

Roux-en-Y gastric bypass is a common surgical procedure used to treat patients with morbid obesity. One of the rare, but potentially fatal complications of gastric bypass is upper gastrointestinal bleeding, which can pose diagnostic and therapeutic dilemmas. This report describes a 39-year-old male with morbid obesity who underwent a Roux-en-Y gastric bypass. Three months postoperatively, he sustained repeated and severe upper attacks of upper gastrointestinal bleeding. He received multiple blood transfusions, and had repeated upper and lower endoscopies with no diagnostic yield. Finally, he underwent laparoscopic endoscopy which revealed a bleeding duodenal ulcer. About 5 ml of saline with adrenaline was injected, followed by electrocoagulation to seal the overlying cleft and blood vessel. He was also treated with a course of a proton pump inhibitor and given treatment for H pylori eradication with no further attacks of bleeding. Taking in consideration the difficulties in accessing the bypassed stomach endoscopically, laparoscopic endoscopy is a feasible and valuable diagnostic and therapeutic procedure in patients who had gastric bypass.

Health and performance of calves with forestomach-bypass fed milk replacer.

PubMed

McKinstry, D M; Cason, J L; Albert, T F; Sass, B

1976-02-01

Ten male Holstein calves were placed in groups of two calves each on similarity of age. On calf in each group was subjected to forestomach-bypass surgery at about 1 mo of age. Fortified commercial milk replacer with added minerals and vitamins was fed as the sole diet. The calves were housed indoors on slatted platforms. Weight gain was determined biweekly. Feed intake was determined daily. Necropsies were performed upon termination of the study. Recurrent ruminal bloat, fever, and anorexia of varying degrees and combinations occurred in four of the calves with forestomach bypass. Two of these calves showed slow weight gain. One of the four calves died following acute bloat while the other three calves were sacrificed following repeated episodes of bloat. The time of termination varied between 3 and 10 mo. One calf with forestomach bypass and all control calves appeared healthy throughout the experiment. Necropsies indicated that the ruminal bloat, seen in most of the forestomach-bypass calves, could be attributed to the back-flow of ingesta via the omasal-abomasal orifice. This ingesta appeared to produce gas which became trapped in the bypassed rumen.

A remote augmentor lift system with a turbine bypass engine

NASA Technical Reports Server (NTRS)

Fishbach, L. H.; Franciscus, L. C.

1982-01-01

Two supersonic vertical takeoff or landing (VTOL) aircraft engine types, a conventional medium bypass ratio turbofan, and a turbine bypass turbojet were studied. The aircraft assumed was a clipped delta wing with canard configuration. A VTOL deck launched intercept, DLI, mission with Mach 1.6 dash and cruise segments was used as the design mission. Several alternate missions requiring extended subsonic capabilities were analyzed. Comparisons were made between the turbofan (TF) and the turbine bypass turbojet (TBE) engines in airplane types using a Remote Augmented Lift Systems, RALS and a Lift plus Lift Cruise system (L+LC). The figure of merit was takeoff gross weight for the VTOL DLI mission. The results of the study show that the turbine bypass turbojet and the conventional turbofan are competitive engines for both type of aircraft in terms of takeoff gross weight and range. However, the turbine bypass turbojet would be a simpler engine and may result in more attractive life cycle costs and reduced maintenance. The RALS and L+LC airplane types with either TBE or TF engines have approximately the same aircraft takeoff gross weight.

An Experimental Design of Bypass Magneto-Rheological (MR) damper

NASA Astrophysics Data System (ADS)

Rashid, MM; Aziz, Mohammad Abdul; Raisuddin Khan, Md.

2017-11-01

The magnetorheological (MR) fluid bypass damper fluid flow through a bypass by utilizing an external channel which allows the controllability of MR fluid in the channel. The Bypass MR damper (BMRD) contains a rectangular bypass flow channel, current controlled movable piston shaft arrangement and MR fluid. The static piston coil case is winding by a coil which is used inside the piston head arrangement. The current controlled coil case provides a magnetic flux through the BMRD cylinder for controllability. The high strength of alloy steel materials are used for making piston shaft which allows magnetic flux propagation throughout the BMRD cylinder. Using the above design materials, a Bypass MR damper is designed and tested. An excitation of current is applied during the experiment which characterizes the BMRD controllability. It is shown that the BMRD with external flow channel allows a high controllable damping force using an excitation current. The experimental result of damping force-displacement characteristics with current excitation and without current excitation are compared in this research. The BMRD model is validated by the experimental result at various frequencies and applied excitation current.

Multislice Computed Tomography Accurately Detects Stenosis in Coronary Artery Bypass Conduits

PubMed Central

Duran, Cihan; Sagbas, Ertan; Caynak, Baris; Sanisoglu, Ilhan; Akpinar, Belhhan; Gulbaran, Murat

2007-01-01

The aim of this study was to evaluate the accuracy of multislice computed tomography in detecting graft stenosis or occlusion after coronary artery bypass grafting, using coronary angiography as the standard. From January 2005 through May 2006, 25 patients (19 men and 6 women; mean age, 54 ± 11.3 years) underwent diagnostic investigation of their bypass grafts by multislice computed tomography within 1 month of coronary angiography. The mean time elapsed after coronary artery bypass grafting was 6.2 years. In these 25 patients, we examined 65 bypass conduits (24 arterial and 41 venous) and 171 graft segments (the shaft, proximal anastomosis, and distal anastomosis). Compared with coronary angiography, the segment-based sensitivity, specificity, and positive and negative predictive values of multislice computed tomography in the evaluation of stenosis were 89%, 100%, 100%, and 99%, respectively. The patency rate for multislice compu-ted tomography was 85% (55/65: 3 arterial and 7 venous grafts were occluded), with 100% sensitivity and specificity. From these data, we conclude that multislice computed tomography can accurately evaluate the patency and stenosis of bypass grafts during outpatient follow-up. PMID:17948078

A Score for Predicting Acute Kidney Injury After Coronary Artery Bypass Graft Surgery in an Asian Population.

PubMed

Mithiran, Harish; Kunnath Bonney, Glenn; Bose, Saideep; Subramanian, Srinivas; Zhe Yan, Zan Ng; Zong En, Seth Yeak; Papadimas, Evangelos; Chauhan, Ishaan; MacLaren, Graeme; Kofidis, Theodoros

2016-10-01

To develop a scoring system to predict acute kidney injury in Asian patients after coronary artery bypass grafting. A retrospective analysis of data collected in an institutional cardiac database. A tertiary academic hospital in a large metropolitan city. The study comprised 954 patients with coronary artery disease. All patients underwent coronary artery bypass surgery with cardiopulmonary bypass but did not undergo any other concomitant procedures. The main outcome measured was acute kidney injury as defined by the Acute Kidney Injury Network criteria. The following 6 clinical variables were independent predictors of kidney injury: age>60 years, diabetes requiring insulin, estimated glomerular filtration rate<60 mL/min/1.73 m(2), ejection fraction<40%, cardiopulmonary bypass time>140 minutes, and aortic cross-clamp time>100 minutes. These variables were used to develop the Singapore Acute Kidney Injury score. The Singapore Acute Kidney Injury score is a simple way to predict, at the time of admission to the intensive care unit, an Asian patient's risk of developing acute kidney injury after coronary artery bypass surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

Investigation of bypass fluid flow in an active magnetic regenerative liquefier

DOE PAGES

Holladay, Jamelyn; Teyber, Reed; Meinhardt, Kerry; ...

2018-05-19

Active magnetic regenerators (AMR) with second order magnetocaloric materials operating below the Curie temperature have a unique property where the magnetized specific heat is lower than the demagnetized specific heat. The associated thermal mass imbalance allows a fraction of heat transfer fluid in the cold heat exchanger to bypass the magnetized regenerator. This cold bypassed fluid can precool a process stream as it returns to the hot side, thereby increasing the efficiency of liquefaction and reducing the cost of liquid cryogens. In the present work, the net cooling power of an active magnetic regenerative liquefier is investigated as a functionmore » of the bypass flow fraction. In conclusion, experiments are performed at a fixed temperature span yielding a 30% improvement in net cooling power, affirming the potential of bypass flow in active magnetic regenerative liquefiers.« less

Investigation of bypass fluid flow in an active magnetic regenerative liquefier

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

Holladay, Jamelyn; Teyber, Reed; Meinhardt, Kerry

Active magnetic regenerators (AMR) with second order magnetocaloric materials operating below the Curie temperature have a unique property where the magnetized specific heat is lower than the demagnetized specific heat. The associated thermal mass imbalance allows a fraction of heat transfer fluid in the cold heat exchanger to bypass the magnetized regenerator. This cold bypassed fluid can precool a process stream as it returns to the hot side, thereby increasing the efficiency of liquefaction and reducing the cost of liquid cryogens. In the present work, the net cooling power of an active magnetic regenerative liquefier is investigated as a functionmore » of the bypass flow fraction. Experiments are performed at a fixed temperature span yielding a 30% improvement in net cooling power, affirming the potential of bypass flow in active magnetic regenerative liquefiers.« less

Investigation of bypass fluid flow in an active magnetic regenerative liquefier

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

Holladay, Jamelyn; Teyber, Reed; Meinhardt, Kerry

Active magnetic regenerators (AMR) with second order magnetocaloric materials operating below the Curie temperature have a unique property where the magnetized specific heat is lower than the demagnetized specific heat. The associated thermal mass imbalance allows a fraction of heat transfer fluid in the cold heat exchanger to bypass the magnetized regenerator. This cold bypassed fluid can precool a process stream as it returns to the hot side, thereby increasing the efficiency of liquefaction and reducing the cost of liquid cryogens. In the present work, the net cooling power of an active magnetic regenerative liquefier is investigated as a functionmore » of the bypass flow fraction. In conclusion, experiments are performed at a fixed temperature span yielding a 30% improvement in net cooling power, affirming the potential of bypass flow in active magnetic regenerative liquefiers.« less

Staged venting of fuel cell system during rapid shutdown

DOEpatents

Clingerman, Bruce J.; Doan, Tien M.; Keskula, Donald H.

2002-01-01

A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H.sub.2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example one to five seconds) using conveniently-sized bypass valves. Upon receipt of the rapid shutdown command, the anode inlet of the fuel cell stack is instantaneously vented to a remote vent to remove all H.sub.2 from the stack. Airflow to the cathode inlet of the fuel cell stack gradually diminishes over the bypass period, and when the airflow bypass is complete the cathode inlet is also instantaneously vented to a remote vent to eliminate pressure differentials across the stack.

Staged venting of fuel cell system during rapid shutdown

DOEpatents

Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

2004-09-14

A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H.sub.2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example one to five seconds) using conveniently-sized bypass valves. Upon receipt of the rapid shutdown command, the anode inlet of the fuel cell stack is instantaneously vented to a remote vent to remove all H.sub.2 from the stack. Airflow to the cathode inlet of the fuel cell stack gradually diminishes over the bypass period, and when the airflow bypass is complete the cathode inlet is also instantaneously vented to a remote vent to eliminate pressure differentials across the stack.

Four-Dimensional Flow MRI Analysis of Cerebral Blood Flow Before and After High-Flow Extracranial-Intracranial Bypass Surgery With Internal Carotid Artery Ligation.

PubMed

Orita, Erika; Murai, Yasuo; Sekine, Tetsuro; Takagi, Ryo; Amano, Yasuo; Ando, Takahiro; Iwata, Kotomi; Obara, Makoto; Kumita, Shinichiro

2018-05-11

The hemodynamic changes that occur after high-flow (extracranial-intracranial) EC-IC bypass surgery with internal carotid artery (ICA) ligation are not well known. To assess blood flow changes after high-flow EC-IC bypass with ICA ligation by time-resolved 3-dimensional phase-contrast (4D Flow) magnetic resonance imaging (MRI). We enrolled 11 patients who underwent high-flow EC-IC bypass. 4D Flow MRI was performed before and after surgery to quantify the blood flow volume (BFV) of the ipsilateral ICA (BFViICA), bypass artery (BFVbypass), contralateral ICA (BFVcICA), and basilar artery (BFVBA). Subsequently, we calculated the total BFV (BFVtotal = BFViICA + BFVcICA + BFVBA [before surgery], BFVcICA + BFVBA + BFVbypass [after surgery]). The BFV changes after bypass was statistically analyzed. BFVbypass was slightly lower than BFViICA, but the difference was not statistically significant (3.84 ± 0.94 vs 4.42 ± 1.38 mL/s). The BFVcICA and BFVBA significantly increased after bypass surgery (BFVcICA 5.89 ± 1.44 vs 7.22 ± 1.37 mL/s [P = .0018], BFVBA 3.06 ± 0.41 vs 4.12 ± 0.38 mL/s [P < .001]). The BFVtotal significantly increased after surgery (13.37 ± 2.58 vs 15.18 ± 1.77 mL/s [P = .015]). There was no evidence of hyperperfusion syndrome in any cases. After high-flow EC-IC bypass with permanent ICA ligation, the bypass artery could partially compensate for the loss of BFV of the sacrificed ICA. The increased flow of the contralateral ICA and BA supply collateral blood flow. Clinically irrelevant hyperperfusion was observed.

Cigarette smoking in British men and selection for coronary artery bypass surgery.

PubMed Central

Morris, R. W.; McCallum, A. K.; Walker, M.; Whincup, P. H.; Ebrahim, S.; Shaper, A. G.

1996-01-01

OBJECTIVE: To examine the relation between smoking status, clinical need, and likelihood of coronary artery bypass grafting in middle aged men. DESIGN: A prospective study of cardiovascular disease in British men aged 40 to 59 years, screened in 1978-80 and followed until December 1991. SUBJECTS AND SETTING: 7735 men drawn from one general practice in each of 24 British towns. MAIN OUTCOME MEASURE: Coronary artery bypass graft surgery. RESULTS: Of the 3185 current smokers, 38 (1.03/1000/year) underwent coronary artery bypass surgery compared with 47 of 2715 (1.45/1000/year) ex-smokers, and 19 of 1817 (0.85/1000/year) never-smokers. Ex-smokers had a lower incidence of major ischaemic heart disease during follow up than current smokers. After adjustment for incidence of ischaemic heart disease during follow up, the hazard ratio of coronary artery bypass surgery for ex-smokers compared with smokers was 1.52 (95% confidence interval 0.99 to 2.34). Ex-smokers were more likely at screening to recall a doctor diagnosis of ischaemic heart disease than smokers (7.1% v 5.3%), but among those who recalled a doctor diagnosis, smokers were less likely to undergo coronary artery bypass surgery than ex-smokers (9.4% v 3.5%, P = 0.026). By 1992, men defined as smokers at screening were no less likely than ex-smokers to have been referred to a cardiologist (18.5% v 18.8%), nor to report having undergone coronary angiography less frequently than ex-smokers (12.7% v 11.4%). CONCLUSION: Even allowing for the strong relation between coronary artery bypass surgery and clinical need, continuing smokers were less likely to undergo coronary artery bypass surgery than ex-smokers. A complex interplay exists between the men's experience of heart disease, the decision to stop smoking, and the willingness of doctors to consider coronary artery bypass surgery. PMID:8697156

Functional Dissection of the Blocking and Bypass Activities of the Fab-8 Boundary in the Drosophila Bithorax Complex.

PubMed

Kyrchanova, Olga; Mogila, Vladic; Wolle, Daniel; Deshpande, Girish; Parshikov, Alexander; Cléard, Fabienne; Karch, Francois; Schedl, Paul; Georgiev, Pavel

2016-07-01

Functionally autonomous regulatory domains direct the parasegment-specific expression of the Drosophila Bithorax complex (BX-C) homeotic genes. Autonomy is conferred by boundary/insulator elements that separate each regulatory domain from its neighbors. For six of the nine parasegment (PS) regulatory domains in the complex, at least one boundary is located between the domain and its target homeotic gene. Consequently, BX-C boundaries must not only block adventitious interactions between neighboring regulatory domains, but also be permissive (bypass) for regulatory interactions between the domains and their gene targets. To elucidate how the BX-C boundaries combine these two contradictory activities, we have used a boundary replacement strategy. We show that a 337 bp fragment spanning the Fab-8 boundary nuclease hypersensitive site and lacking all but 83 bp of the 625 bp Fab-8 PTS (promoter targeting sequence) fully rescues a Fab-7 deletion. It blocks crosstalk between the iab-6 and iab-7 regulatory domains, and has bypass activity that enables the two downstream domains, iab-5 and iab-6, to regulate Abdominal-B (Abd-B) transcription in spite of two intervening boundary elements. Fab-8 has two dCTCF sites and we show that they are necessary both for blocking and bypass activity. However, CTCF sites on their own are not sufficient for bypass. While multimerized dCTCF (or Su(Hw)) sites have blocking activity, they fail to support bypass. Moreover, this bypass defect is not rescued by the full length PTS. Finally, we show that orientation is critical for the proper functioning the Fab-8 replacement. Though the inverted Fab-8 boundary still blocks crosstalk, it disrupts the topology of the Abd-B regulatory domains and does not support bypass. Importantly, altering the orientation of the Fab-8 dCTCF sites is not sufficient to disrupt bypass, indicating that orientation dependence is conferred by other factors.

Functional Dissection of the Blocking and Bypass Activities of the Fab-8 Boundary in the Drosophila Bithorax Complex

PubMed Central

Wolle, Daniel; Deshpande, Girish; Parshikov, Alexander; Cléard, Fabienne; Karch, Francois; Schedl, Paul; Georgiev, Pavel

2016-01-01

Functionally autonomous regulatory domains direct the parasegment-specific expression of the Drosophila Bithorax complex (BX-C) homeotic genes. Autonomy is conferred by boundary/insulator elements that separate each regulatory domain from its neighbors. For six of the nine parasegment (PS) regulatory domains in the complex, at least one boundary is located between the domain and its target homeotic gene. Consequently, BX-C boundaries must not only block adventitious interactions between neighboring regulatory domains, but also be permissive (bypass) for regulatory interactions between the domains and their gene targets. To elucidate how the BX-C boundaries combine these two contradictory activities, we have used a boundary replacement strategy. We show that a 337 bp fragment spanning the Fab-8 boundary nuclease hypersensitive site and lacking all but 83 bp of the 625 bp Fab-8 PTS (promoter targeting sequence) fully rescues a Fab-7 deletion. It blocks crosstalk between the iab-6 and iab-7 regulatory domains, and has bypass activity that enables the two downstream domains, iab-5 and iab-6, to regulate Abdominal-B (Abd-B) transcription in spite of two intervening boundary elements. Fab-8 has two dCTCF sites and we show that they are necessary both for blocking and bypass activity. However, CTCF sites on their own are not sufficient for bypass. While multimerized dCTCF (or Su(Hw)) sites have blocking activity, they fail to support bypass. Moreover, this bypass defect is not rescued by the full length PTS. Finally, we show that orientation is critical for the proper functioning the Fab-8 replacement. Though the inverted Fab-8 boundary still blocks crosstalk, it disrupts the topology of the Abd-B regulatory domains and does not support bypass. Importantly, altering the orientation of the Fab-8 dCTCF sites is not sufficient to disrupt bypass, indicating that orientation dependence is conferred by other factors. PMID:27428541

Evaluation of a prototype surface flow bypass for juvenile salmon and steelhead at the powerhouse of Lower Granite Dam, Snake River, Washington, 1996-2000

USGS Publications Warehouse

Johnson, G.E.; Anglea, S.M.; Adams, N.S.; Wik, T.O.

2005-01-01

A surface flow bypass takes advantage of the natural surface orientation of most juvenile salmon Oncorhynchus spp. and steelhead O. mykiss by providing a route in the upper water column that downstream migrant fishes can use to pass a hydroelectric dam safely. A prototype structure, called the surface bypass and collector (SBC), was retrofitted on the powerhouse of Lower Granite Dam and was evaluated annually with biotelemetry and hydroacoustic techniques during the 5-year life span of the structure (1996-2000) to determine the entrance configuration that maximized passage efficiency and minimized forebay residence time. The best tested entrance configuration had maximum inflow (99 m 3/s) concentrated in a single surface entrance (5 m wide, 8.5 m deep). We identified five important considerations for future surface flow bypass development in the lower Snake River and elsewhere: (1) an extensive flow net should be formed in the forebay by use of relatively high surface flow bypass discharge (>7% of total project discharge); (2) a gradual increase in water velocity with increasing proximity to the surface flow bypass (ideally, acceleration 3 m/s) to entrain the subject juvenile fishes; (4) the shape and orientation of the surface entrance(s) should be adapted to fit site-specific features; and (5) construction of a forebay wall to increase fish availability to the surface flow bypass should be considered. The efficiency of the SBC was not high enough (maximum of 62% relative to passage at turbine units 4-5) for the SBC to operate as a stand-alone bypass. Anywhere that surface-oriented anadromous fish must negotiate hydroelectric dams, surface flow bypass systems can provide cost-effective use of typically limited water supplies to increase the nonturbine passage, and presumably survival, of downstream migrants. ??Copyright by the American Fisheries Society 2005.

Intraoperative sonographic assessment of graft patency during extracranial-intracranial bypass.

PubMed

Badie, B; Lee, F T; Pozniak, M A; Strother, C M

2000-09-01

Extracranial-intracranial (EC-IC) bypass may be necessary to facilitate treatment of unclippable posterior circulation fusiform aneurysms. Although intraoperative digital subtraction angiography (DSA) allows assessment of graft patency, this technique, because of difficulties inherent in performing selective catheterization and angiography in the operating room, has limitations. Duplex sonography, in contrast, is easily performed, and provides information regarding graft patency and blood flow direction during EC-IC bypass procedures. This latter information proved useful in determining the time of parent artery occlusion after two EC-IC bypass procedures performed for treatment of a fusiform midbasilar artery aneurysm.

Cardiopulmonary bypass with bivalirudin in type II heparin-induced thrombocytopenia.

PubMed

Clayton, Stephanie B; Acsell, Jeffrey R; Crumbley, Arthur J; Uber, Walter E

2004-12-01

Cardiopulmonary bypass in patients with type II heparin induced-thrombocytopenia poses significant challenges. Inadequate pharmacokinetic profiles, monitoring, reversibility, and availability often limit alternative anticoagulation strategies. Bivalirudin, a semisynthetic direct thrombin inhibitor, was recently approved for use in patients undergoing percutaneous coronary interventions. Its unique properties, including a relatively short half-life, an anticoagulation effect that closely correlates with activated clotting time, and an alternate metabolic pathway for elimination, make bivalirudin an attractive agent for cardiopulmonary bypass in patients with type II heparin induced-thrombocytopenia. We report our experience using bivalirudin in 2 patients undergoing coronary artery bypass grafting.

Outcomes of sympathectomy and vascular bypass for digital ischaemia in connective tissue disorders.

PubMed

Shammas, R L; Hwang, B H; Levin, L S; Richard, M J; Ruch, D S; Mithani, S K

2017-10-01

All patients (36 hands) with connective tissue disorders who underwent periarterial sympathectomy of the hand alone or in conjunction with vascular bypass at our institution between 1995-2013 were reviewed. The durable resolution of ulcers was significantly higher in patients treated by periarterial sympathectomy and bypass than in patients treated by periarterial sympathectomy alone. Although there were more digital amputations in patients treated by periarterial sympathectomy alone, the difference was not statistically significant. Vascular bypass in conjunction with sympathectomy may be better than sympathectomy alone in patients with digital ischaemia related to connective tissue disorders. IV.

The tethered bezoar as a delayed complication of laparoscopic Roux-en-Y gastric bypass: a case report.

PubMed

Pratt, Janey S A; Van Noord, Michael; Christison-Lagay, Emily

2007-05-01

Known complications of Roux-en-Y gastric bypass causing abdominal pain and obstructive symptoms include biliary colic, anastomotic ulcer, anastomotic stenosis, or internal hernia. This case report describes a new complication in a patient 15 months post-bypass: a bezoar at the gastrojejunal anastomosis, the nidus of which was a length of permanent suture material which had eroded through the gastric wall. We include endoscopic images of the bezoar, a review of the related gastric bypass literature, and describe the changes made in our practice as a result of this complication.

Prior failed ipsilateral percutaneous endovascular intervention in patients with critical limb ischemia predicts poor outcome after lower extremity bypass

PubMed Central

Nolan, Brian W.; De Martino, Randall R.; Stone, David H.; Schanzer, Andres; Goodney, Philip P.; Walsh, Daniel W.; Cronenwett, Jack L.

2017-01-01

Background Although open surgical bypass remains the standard revascularization strategy for patients with critical limb ischemia (CLI), many centers now perform peripheral endovascular intervention (PVI) as the first-line treatment for these patients. We sought to determine the effect of a prior ipsilateral PVI (iPVI) on the outcome of subsequent lower extremity bypass (LEB) in patients with CLI. Methods A retrospective cohort analysis of all patients undergoing infrainguinal LEB between 2003 and 2009 within hospitals comprising the Vascular Study Group of New England (VSGNE) was performed. Primary study endpoints were major amputation and graft occlusion at 1 year postoperatively. Secondary outcomes included in-hospital major adverse events (MAE), 1-year mortality, and composite 1-year major adverse limb events (MALE). Event rates were determined using life table analyses and comparisons were performed using the log-rank test. Multivariate predictors were determined using a Cox proportional hazards model with multilevel hierarchical adjustment. Results Of 1880 LEBs performed, 32% (n = 603) had a prior infrainguinal revascularization procedure (iPVI, 7%; ipsilateral bypass, 15%; contralateral PVI, 3%; contralateral bypass, 17%). Patients with prior iPVI, compared with those without a prior iPVI, were more likely to be women (32 vs 41%; P = .04), less likely to have tissue loss (52% vs 63%; P = .02), more likely to require arm vein conduit (16% vs 5%; P = .001), and more likely to be on statin (71% vs 54%; P = .01) and beta blocker therapy (92% vs 81%; P = .01) at the time of their bypass procedure. Other demographic factors were similar between these groups. Prior PVI or bypass did not alter 30-day MAE and 1-year mortality after the index bypass. In contrast, 1-year major amputation and 1-year graft occlusion rates were significantly higher in patients who had prior iPVI than those without (31% vs 20%; P = .046 and 28% vs 18%; P = .009), similar to patients who had a prior ipsilateral bypass (1 year major amputation, 29% vs 20%; P = .022; 1 year graft occlusion, 33% vs 18%; P = .001). Independent multivariate predictors of higher 1-year amputation and graft occlusion rates were prior iPVI, prior ipsilateral bypass, dialysis dependence, prosthetic conduit and distal (tibial and pedal) bypass target. Conclusions Prior iPVI is highly predictive for poor outcome in patients undergoing LEB for CLI with higher 1-year amputation and graft occlusion rates than those without prior revascularization, similar to prior ipsilateral bypass These findings provide information, which may help with the complex decisions surrounding revascularization options in patients with CLI. PMID:21802888

Bypass flow computations on the LOFA transient in a VHTR

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

Tung, Yu-Hsin; Johnson, Richard W.; Ferng, Yuh-Ming

2014-01-01

Bypass flow in the prismatic gas-cooled very high temperature reactor (VHTR) is not intentionally designed to occur, but is present in the gaps between graphite blocks. Previous studies of the bypass flow in the core indicated that the cooling provided by flow in the bypass gaps had a significant effect on temperature and flow distributions for normal operating conditions. However, the flow and heat transports in the core are changed significantly after a Loss of Flow Accident (LOFA). This study aims to study the effect and role of the bypass flow after a LOFA in terms of the temperature andmore » flow distributions and for the heat transport out of the core by natural convection of the coolant for a 1/12 symmetric section of the active core which is composed of images and mirror images of two sub-region models. The two sub-region models, 9 x 1/12 and 15 x 1/12 symmetric sectors of the active core, are employed as the CFD flow models using computational grid systems of 70.2 million and 117 million nodes, respectively. It is concluded that the effect of bypass flow is significant for the initial conditions and the beginning of LOFA, but the bypass flow has little effect after a long period of time in the transient computation of natural circulation.« less

Sensitivity of the downward to sweeping velocity ratio to the bypass flow percentage along a guide wall for downstream fish passage

USGS Publications Warehouse

Mulligan, Kevin; Towler, Brett; Haro, Alexander J.; Ahlfeld, David P.

2017-01-01

Partial-depth impermeable guidance structures (or guide walls) are used as a method to assist in the downstream passage of fish at a hydroelectric facility. However, guide walls can result in a strong downward velocity causing the approaching fish to pass below the wall and into the direction of the turbine intakes. The objective of this study was to describe how the ratio of the vertical velocity to the sweeping velocity magnitude changes along the full length and depth of a guide wall under a wide range of bypass flow percentages within a power canal. This paper focused on two guide wall configurations, each set at an angle of 45 ° to the approaching flow field and at a depth of 10 and 20 ft (3.05 and 6.10 m). The hydraulic conditions upstream of each guide wall configuration were shown to be impacted by a change in the bypass flow percentage, not only near the bypass but also at upstream sections of the guide wall. Furthermore, the effect of changing the bypass flow percentage was similar for both guide wall depths. In both cases, the effect of increasing the bypass flow percentage was magnified closer to the bypass and deeper in the water column along the guide wall.

Impact of mean arterial pressure on sublingual microcirculation during cardiopulmonary bypass - secondary outcome from a randomised clinical trial.

PubMed

Holmgaard, Frederik; Vedel, Anne G; Ravn, Hanne Berg; Nilsson, Jens C; Rasmussen, Lars S

2018-05-13

In this substudy of a randomised, clinical trial, we explored the sublingual microcirculation during cardiac surgery at two different levels of blood pressure. We hypothesised that a higher mean arterial pressure during cardiopulmonary bypass would cause higher Microvascular Flow Index. Thirty-six cardiac surgery patients undergoing coronary artery bypass grafting were included and randomised to either low (40-50 mmHg) or high (70-80 mmHg) mean arterial pressure during cardiopulmonary bypass. Sidestream Dark Field video images were recorded from the sublingual mucosa. Recordings were analysed in a blinded fashion to quantify microcirculatory variables. Mean arterial pressure during cardiopulmonary bypass in the low target group was 45.0 mmHg (SD 5.3) vs. 67.2 mmHg (SD 8.9) in the high target group. We found no significant difference between the two groups in Microvascular Flow Index during cardiopulmonary bypass evaluated for all vessels: 2.91 vs. 2.90 (p = 0.82). For small vessels (< 20 micrometers), the corresponding values were 2.87 and 2.85 in the low and high target groups, respectively (p = 0.82). We found no significant difference in sublingual microcirculatory flow expressed as Microvascular Flow Index according to two different levels of mean arterial pressure during cardiopulmonary bypass. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO2...

Code of Federal Regulations, 2011 CFR

2011-07-01

... emissions from common, bypass, and multiple stacks for SO2 emissions and heat input determinations. 75.16... emissions from common, bypass, and multiple stacks for SO2 emissions and heat input determinations. (a... by the Administrator, such that these emissions are not underestimated. (e) Heat input rate. The...

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO 2...

Code of Federal Regulations, 2013 CFR

2013-07-01

... emissions from common, bypass, and multiple stacks for SO 2 emissions and heat input determinations. 75.16... emissions from common, bypass, and multiple stacks for SO 2 emissions and heat input determinations. (a... by the Administrator, such that these emissions are not underestimated. (e) Heat input rate. The...

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO2...

Code of Federal Regulations, 2012 CFR

2012-07-01

... emissions from common, bypass, and multiple stacks for SO2 emissions and heat input determinations. 75.16... emissions from common, bypass, and multiple stacks for SO2 emissions and heat input determinations. (a... by the Administrator, such that these emissions are not underestimated. (e) Heat input rate. The...

40 CFR 75.16 - Special provisions for monitoring emissions from common, bypass, and multiple stacks for SO 2...

Code of Federal Regulations, 2014 CFR

2014-07-01

... emissions from common, bypass, and multiple stacks for SO 2 emissions and heat input determinations. 75.16... emissions from common, bypass, and multiple stacks for SO 2 emissions and heat input determinations. (a... by the Administrator, such that these emissions are not underestimated. (e) Heat input rate. The...

76 FR 22059 - Airworthiness Directives; The Boeing Company Model 757 Airplanes, and Model 767-200, 767-300, and...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-20

... procedures to follow to ensure that a fuel filter impending bypass condition due to gross fuel contamination... fuel filter impending bypass condition due to gross fuel contamination is detected in a timely manner... flight crew of a left engine fuel filter contamination and imminent bypass condition, which may indicate...

Reverse bias protected solar array with integrated bypass battery

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A (Inventor)

2012-01-01

A method for protecting the photovoltaic cells in a photovoltaic (PV) array from reverse bias damage by utilizing a rechargeable battery for bypassing current from a shaded photovoltaic cell or group of cells, avoiding the need for a bypass diode. Further, the method mitigates the voltage degradation of a PV array caused by shaded cells.

40 CFR 63.1569 - What are my requirements for HAP emissions from bypass lines?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 12 2010-07-01 2010-07-01 true What are my requirements for HAP emissions from bypass lines? 63.1569 Section 63.1569 Protection of Environment ENVIRONMENTAL PROTECTION... HAP emissions from bypass lines? (a) What work practice standards must I meet? (1) You must meet each...

40 CFR Table 37 to Subpart Uuu of... - Requirements for Performance Tests for Bypass Lines

Code of Federal Regulations, 2012 CFR

2012-07-01

... Bypass Lines 37 Table 37 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION... Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Pt. 63, Subpt. UUU, Table 37 Table 37 to Subpart UUU of Part 63—Requirements for Performance Tests for Bypass Lines As...

40 CFR Table 37 to Subpart Uuu of... - Requirements for Performance Tests for Bypass Lines

Code of Federal Regulations, 2014 CFR

2014-07-01

... Bypass Lines 37 Table 37 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION... Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Pt. 63, Subpt. UUU, Table 37 Table 37 to Subpart UUU of Part 63—Requirements for Performance Tests for Bypass Lines As...

40 CFR Table 37 to Subpart Uuu of... - Requirements for Performance Tests for Bypass Lines

Code of Federal Regulations, 2013 CFR

2013-07-01

... Bypass Lines 37 Table 37 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION... Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Pt. 63, Subpt. UUU, Table 37 Table 37 to Subpart UUU of Part 63—Requirements for Performance Tests for Bypass Lines As...

The effects of New York's bypass surgery provider profiling on access to care and patient outcomes in the elderly.

PubMed

Peterson, E D; DeLong, E R; Jollis, J G; Muhlbaier, L H; Mark, D B

1998-10-01

The aim of this study was to examine the effects of provider profiling on bypass surgery access and outcomes in elderly patients in New York. Since 1989, New York (NY) has compiled provider-specific bypass surgery mortality reports. While some have proposed that "provider profiling" has led to lower surgical mortality rates, critics have suggested that such programs lower in-state procedural access (increasing out-of-state transfers) without improving patient outcomes. Using national Medicare data, we examined trends in the percentages of NY residents aged 65 years or older receiving out-of-state bypass surgery between 1987 and 1992 (before and after program initiation). We also examined in-state procedure use among elderly myocardial infarction patients during this period. Finally, we compared trends in surgical outcomes in NY Medicare patients with those for the rest of the nation. Between 1987 and 1992, the percentage of NY residents receiving bypass out-of-state actually declined (from 12.5% to 11.3%, p < 0.01 for trend). An elderly patient's likelihood for bypass following myocardial infarction in NY increased significantly since the program's initiation. Between 1987 and 1992, unadjusted 30-day mortality rates following bypass declined by 33% in NY Medicare patients compared with a 19% decline nationwide (p < 0.001). As a result of this improvement, NY had the lowest risk-adjusted bypass mortality rate of any state in 1992. We found no evidence that NY's provider profiling limited procedure access in NY's elderly or increased out-of-state transfers. Despite an increasing preoperative risk profile, procedural outcomes in NY improved significantly faster than the national average.

Brain microvascular function during cardiopulmonary bypass

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

Sorensen, H.R.; Husum, B.; Waaben, J.

1987-11-01

Emboli in the brain microvasculature may inhibit brain activity during cardiopulmonary bypass. Such hypothetical blockade, if confirmed, may be responsible for the reduction of cerebral metabolic rate for glucose observed in animals subjected to cardiopulmonary bypass. In previous studies of cerebral blood flow during bypass, brain microcirculation was not evaluated. In the present study in animals (pigs), reduction of the number of perfused capillaries was estimated by measurements of the capillary diffusion capacity for hydrophilic tracers of low permeability. Capillary diffusion capacity, cerebral blood flow, and cerebral metabolic rate for glucose were measured simultaneously by the integral method, different tracersmore » being used with different circulation times. In eight animals subjected to normothermic cardiopulmonary bypass, and seven subjected to hypothermic bypass, cerebral blood flow, cerebral metabolic rate for glucose, and capillary diffusion capacity decreased significantly: cerebral blood flow from 63 to 43 ml/100 gm/min in normothermia and to 34 ml/100 gm/min in hypothermia and cerebral metabolic rate for glucose from 43.0 to 23.0 mumol/100 gm/min in normothermia and to 14.1 mumol/100 gm/min in hypothermia. The capillary diffusion capacity declined markedly from 0.15 to 0.03 ml/100 gm/min in normothermia but only to 0.08 ml/100 gm/min in hypothermia. We conclude that the decrease of cerebral metabolic rate for glucose during normothermic cardiopulmonary bypass is caused by interruption of blood flow through a part of the capillary bed, possibly by microemboli, and that cerebral blood flow is an inadequate indicator of capillary blood flow. Further studies must clarify why normal microvascular function appears to be preserved during hypothermic cardiopulmonary bypass.« less

Rural Patients with Severe Sepsis or Septic Shock who Bypass Rural Hospitals have Increased Mortality: An Instrumental Variables Approach

PubMed Central

Mohr, Nicholas M.; Harland, Karisa K.; Shane, Dan M.; Ahmed, Azeemuddin; Fuller, Brian M.; Ward, Marcia M.; Torner, James C.

2016-01-01

Objective To identify factors associated with rural sepsis patients’ bypassing rural emergency departments (EDs) to seek emergency care in larger hospitals, and to measure the association between rural hospital bypass and sepsis survival. Design, Setting, and Patients Cohort study of adults treated in EDs of a rural Midwestern state with severe sepsis or septic shock between 2005 and 2014, using administrative claims data. Patients residing ≥ 20 miles from a top-decile sepsis volume hospital and < 20 miles from a local hospital were included. Interventions Patients bypassing local rural hospitals to seek care in larger hospitals. Measurements and Main Results A total of 13,461 patients were included, and only 5.4% (n = 731) bypassed a rural hospital for their ED care. Patients who initially chose a top-decile sepsis volume hospital were younger (64.7 vs. 72.7 y, p<0.001) and were more likely to have commercial insurance (19.6% vs. 10.6%, p<0.001) than those who were seen initially at a local rural hospital. They were also more likely to have significant medical comorbidities, such as liver failure (9.9% vs 4.2%, p<0.001), metastatic cancer (5.9% vs 3.2%, p<0.001), and diabetes with complications (25.2% vs. 21.6%, p=0.024). Using an instrumental variables approach, rural hospital bypass was associated with a 5.6% increase (95%CI 2.2 – 8.9%) in mortality. Conclusions Most rural patients with sepsis seek care in local EDs, but demographic and disease-oriented factors are associated with rural hospital bypass. Rural hospital bypass is independently associated with increased mortality. PMID:27611977

Intracerebral Hemorrhage Caused by Cerebral Hyperperfusion after Superficial Temporal Artery to Middle Cerebral Artery Bypass for Atherosclerotic Occlusive Cerebrovascular Disease

PubMed Central

Matano, Fumihiro; Murai, Yasuo; Mizunari, Takayuki; Adachi, Koji; Kobayashi, Shiro; Morita, Akio

Few papers have reported detailed accounts of intracerebral hemorrhage caused by cerebral hyperperfusion after superficial temporal artery to middle cerebral artery bypass (STA-MCA) bypass for atherosclerotic occlusive cerebrovascular disease. We report a case of vasogenic edema and subsequent intracerebral hemorrhage caused by the cerebral hyperperfusion syndrome (CHS) after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease disease without intense postoperative blood pressure control. A 63-year-old man with repeating left hemiparesis underwent magnetic resonance angiography (MRA), which revealed right internal carotid artery (ICA) occlusion. We performed a double bypass superficial temporal artery (STA)–middle cerebral artery (MCA) bypass surgery for the M2 and M3 branches. While the patient’s postoperative course was relatively uneventful, he suffered generalized convulsions, and computed tomography revealed a low area in the right frontal lobe on Day 4 after surgery. We considered this lesion to be pure vasogenic edema caused by cerebral hyperperfusion after revascularization. Intravenous drip infusion of a free radical scavenger (edaravone) and efforts to reduce systolic blood pressure to <120 mmHg were continued. The patient experienced severe left hemiparesis and disturbance of consciousness on Day 8 after surgery, due to intracerebral hemorrhage in the right frontal lobe at the site of the earlier vasogenic edema. Brain edema associated with cerebral hyperperfusion after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease should be recognized as a risk factor for intracerebral hemorrhage. The development of brain edema associated with CHS after STA-MCA bypass for atherosclerotic occlusive cerebrovascular disease requires not only intensive control of blood pressure, but also consideration of sedation therapy with propofol. PMID:28664022

Long-term Effects of Off-Pump Coronary Bypass Versus Conventional Coronary Bypass Grafting on Renal Function.

PubMed

Hynes, Conor F; Colo, Sanchez; Amdur, Richard L; Chawla, Lakhmir S; Greenberg, Michael D; Trachiotis, Gregory D

2016-01-01

This study aimed to evaluate the short- and long-term effects of conventional on-pump coronary bypass grafting (cCABG) compared with off-pump coronary artery bypass (OPCAB) on renal function. A retrospective review of patients undergoing coronary bypass grafting from 2004 through 2013 at a single center was conducted. Preoperative renal function, perioperative acute kidney injury, and long-term glomerular filtration were evaluated. Multivariable analyses were used to determine factors contributing to short- and long-term renal impairment. A total of 234 patients underwent cCABG, and 582 underwent OPCAB. Patients undergoing OPCAB were significantly older, had greater preoperative renal dysfunction, had greater functional dependence, and took more hypertension medications. Multivariable analyses found that 30-day acute kidney injury was an independent risk factor for a 10% decline in glomerular filtration rate at 1 and 5 years (P < 0.0001 and 0.002, respectively). However, the use of cardiopulmonary bypass was not found to influence long-term renal function (P = 0.78 at 1 year, P = 0.76 at 5 years). The percentage of patients experiencing a 10% drop in renal function from baseline at 1 year (33% OPCAB, 35% cCABG; P = 0.73) and 5 years (16% OPCAB, 16% cCABG; P = 0.93) were not significantly different. Independent predictors of acute kidney injury included baseline kidney function (P = 0.04) and age (P < 0.0001), whereas cardiopulmonary bypass did not affect the incidence (P = 0.17). A propensity-matched analysis confirmed these findings. Acute kidney injury is a risk factor for long-term renal dysfunction after either bypass method and was not greater after cCABG compared with OPCAB. Patients undergoing OPCAB did not experience greater decrease in long-term kidney function despite having worse baseline kidney function.

Target vessel detection by epicardial ultrasound in off-pump coronary bypass surgery.

PubMed

Hayakawa, Masato; Asai, Tohru; Kinoshita, Takeshi; Suzuki, Tomoaki; Shiraishi, Shoichiro

2013-01-01

The detection of embedded coronary arteries is difficult especially in off-pump coronary bypass surgery. From June 2010, we introduced high-frequency epicardial ultrasound (ECUS) to assess and evaluate embedded arteries during off-pump coronary bypass surgery. Between June 2010 and June 2011, a total of 89 consecutive patients underwent isolated coronary bypass surgery at our institution. The patients consisted of 72 men and 17 women with a mean age of 67.9 years. We routinely use the VeriQC system (MediStim, Oslo, Norway) to detect the target vessels in the operation. The patients were assigned to one of two groups, depending on whether ECUS was used in the operation (n = 10, ECUS group) or not (n = 79, non-ECUS group). We analyzed the impact of introducing the ECUS in terms of operative outcome. All patients underwent revascularization using the off-pump technique without emergent conversion to cardiopulmonary bypass during surgery. The total number of distal anastomoses was 299, and 12 target vessels could not be identified either visually or on palpation. Thus, the frequency of the embedded coronary arteries was 4.01% (12/299 cases). The preoperative profiles of the two groups were not significantly different. Operation time was significantly longer in the ECUS group (P = 0.02). There were no significant differences in postoperative outcome between the two groups. In the present study, in which the target coronary arteries could not be detected either visually or on palpation in 12 (4.01%) of 299 cases, the use of high-frequency ECUS allowed all patients to undergo off-pump coronary bypass surgery without conversion to cardiopulmonary bypass during the operation. High-frequency ECUS is therefore useful in off-pump coronary bypass surgery.

Potential Impact on Spatial Access to Surgery Under a Low Volume Pledge: A Population-Level Analysis of Patients Undergoing Pancreatectomy

PubMed Central

Fong, Zhi Ven; Loehrer, Andrew P; Castillo, Carlos Fernández-del; Bababekov, Yanik J; Jin, Ginger; Ferrone, Cristina R; Warshaw, Andrew L; Traeger, Lara N; Hutter, Matthew M; Lillemoe, Keith D; Chang, David C

2018-01-01

Background A minimum-volume policy restricting hospitals not meeting the threshold from performing complex surgery may increase travel burden and decrease spatial access to surgery. We aim to identify vulnerable populations that would be sensitive to an added travel burden. Methods We performed a retrospective analysis of the California Office of Statewide Health Planning and Development database for patients undergoing pancreatectomy from 2005 to 2014. Number of hospitals bypassed was used as a metric for travel. Patients bypassing fewer hospitals were deemed to be more sensitive to an added travel burden. Results There were 13,374 patients who underwent a pancreatectomy, of which 2,368 (17.7%) were non-bypassers. On unadjusted analysis, patients >80 year old travelled less than their younger counterparts, bypassing a mean of 10.9 ± 9.5 hospitals compared to 14.2 ± 21.3 hospitals bypassed by the 35–49 year old age group (p<0.001). Racial minorities travelled less when compared to Non-Hispanic Whites (p<0.001). Patients identifying their payer status as self-pay (8.9 ± 15.6 hospitals bypassed) and Medicaid (10.1 ± 17.2 hospitals bypassed) also travelled less when compared to patients with private insurance (13.8 ± 20.4 hospitals bypassed, p<0.001). On multivariate analysis, advanced age, racial minority and patients with self-pay or Medicaid payer status were independently associated with increased sensitivity to an added travel burden. Conclusion In patients undergoing pancreatectomy, the elderly, racial minorities and patients with self-pay or Medicaid payer status were associated with an increased sensitivity to an added travel burden. This vulnerable cohort may be disproportionately affected by a minimum-volume policy. PMID:28504112

Myocardial Viability and Impact of Surgical Ventricular Reconstruction on Outcomes of Patients with Severe Left Ventricular Dysfunction Undergoing Coronary Artery Bypass Surgery: Results of the Surgical Treatment for Ischemic Heart Failure (STICH) Trial

PubMed Central

Holly, Thomas A.; Bonow, Robert O.; Arnold, J. Malcolm O.; Oh, Jae K.; Varadarajan, Padmini; Pohost, Gerald M.; Haddad, Haissam; Jones, Robert H.; Velazquez, Eric J.; Birkenfeld, Bozena; Asch, Federico M.; Malinowski, Marcin; Barretto, Rodrigo; Kalil, Renato A.K.; Berman, Daniel S.; Sun, Jie-Lena; Lee, Kerry L.; Panza, Julio A.

2014-01-01

Objective In the Surgical Treatment for Ischemic Heart Failure (STICH) trial, surgical ventricular reconstruction plus coronary artery bypass surgery was not associated with a reduction in the rate of death or cardiac hospitalization compared to bypass alone. We hypothesized that the absence of viable myocardium identifies patients with coronary artery disease and left ventricular dysfunction who have a greater benefit with coronary artery bypass graft surgery and surgical ventricular reconstruction compared to bypass alone. Methods Myocardial viability was assessed by single photon computed tomography in 267 of the 1,000 patients randomized to bypass or bypass plus surgical ventricular reconstruction in STICH. Myocardial viability was assessed on a per patient basis as well as regionally based on pre-specified criteria. Results At 3 years, there was no difference in mortality or the combined outcome of death or cardiac hospitalization between those with and those without viability, and there was no significant interaction between the type of surgery and global viability status with respect to mortality or death plus cardiac hospitalization. Furthermore, there was no difference in mortality or death plus cardiac hospitalization between those with and without anterior wall or apical scar, and no significant interaction between the presence of scar in these regions and the type of surgery with respect to mortality. Conclusion In patients with coronary artery disease and severe regional left ventricular dysfunction, assessment of myocardial viability does not identify patients who will derive a mortality benefit from adding surgical ventricular reconstruction to coronary artery bypass graft surgery. PMID:25152476

Metabolic Profiles Predict Adverse Events Following Coronary Artery Bypass Grafting

PubMed Central

Shah, Asad A.; Craig, Damian M.; Sebek, Jacqueline K.; Haynes, Carol; Stevens, Robert C.; Muehlbauer, Michael J.; Granger, Christopher B.; Hauser, Elizabeth R.; Newby, L. Kristin; Newgard, Christopher B.; Kraus, William E.; Hughes, G. Chad; Shah, Svati H.

2012-01-01

Objectives Clinical models incompletely predict outcomes following coronary artery bypass grafting. Novel molecular technologies may identify biomarkers to improve risk stratification. We examined whether metabolic profiles can predict adverse events in patients undergoing coronary artery bypass grafting. Methods The study population comprised 478 subjects from the CATHGEN biorepository of patients referred for cardiac catheterization who underwent coronary artery bypass grafting after enrollment. Targeted mass spectrometry-based profiling of 69 metabolites was performed in frozen, fasting plasma samples collected prior to surgery. Principal-components analysis and Cox proportional hazards regression modeling were used to assess the relation between metabolite factor levels and a composite outcome of post-coronary artery bypass grafting myocardial infarction, need for percutaneous coronary intervention, repeat coronary artery bypass grafting, or death. Results Over a mean follow-up of 4.3 ± 2.4 years, 126 subjects (26.4%) suffered an adverse event. Three principal-components analysis-derived factors were significantly associated with adverse outcome in univariable analysis: short-chain dicarboxylacylcarnitines (factor 2, P=0.001); ketone-related metabolites (factor 5, P=0.02); and short-chain acylcarnitines (factor 6, P=0.004). These three factors remained independently predictive of adverse outcome after multivariable adjustment: factor 2 (adjusted hazard ratio 1.23; 95% confidence interval [1.10-1.38]; P<0.001), factor 5 (1.17 [1.01-1.37], P=0.04), and factor 6 (1.14 [1.02-1.27], P=0.03). Conclusions Metabolic profiles are independently associated with adverse outcomes following coronary artery bypass grafting. These profiles may represent novel biomarkers of risk that augment existing tools for risk stratification of coronary artery bypass grafting patients and may elucidate novel biochemical pathways that mediate risk. PMID:22306227

Elevated fasting and postprandial C-terminal telopeptide after Roux-en-Y gastric bypass.

PubMed

Maghsoodi, Negar; Alaghband-Zadeh, Jamshid; Cross, Gemma F; Werling, Malin; Fändriks, Lars; Docherty, Neil G; Olbers, Torsten; Dew, Tracy; Sherwood, Roy A; Vincent, Royce P; le Roux, Carel W

2017-07-01

Background Roux-en-Y gastric bypass increases circulating bile acid concentrations, known mediators of postprandial suppression of markers of bone resorption. Long-term data, however, indicate that Roux-en-Y gastric bypass confers an increased risk of bone loss on recipients. Methods Thirty-six obese individuals, median age 44 (26-64) with median body mass index at baseline of 42.5 (40.4-46) were studied before and 15 months after Roux-en-Y gastric bypass. After an overnight fast, patients received a 400 kcal mixed meal. Blood samples were collected premeal then at 30-min periods for 120 min. Pre and postmeal samples were analysed for total bile acids, parathyroid hormone and C-terminal telopeptide. Results Body weight loss post Roux-en-Y gastric bypass was associated with a median 4.9-fold increase in peak postprandial total bile acid concentration, and a median 2.4-fold increase in cumulative food evoked bile acid response. Median fasting parathyroid hormone, postprandial reduction in parathyroid hormone and total parathyroid hormone release over 120 min remained unchanged after surgery. After surgery, median fasting C-terminal telopeptide increased 2.3-fold, peak postprandial concentrations increased 3.8-fold and total release was increased 1.9-fold. Conclusions Fasting and postprandial total bile acids and C-terminal telopeptide are increased above reference range after Roux-en-Y gastric bypass. These changes occur in spite of improved vitamin D status with supplementation. These results suggest that post-Roux-en-Y gastric bypass increases in total bile acids do not effectively oppose an ongoing resorptive signal operative along the gut-bone axis. Serial measurement of C-terminal telopeptide may be of value as a risk marker for long-term skeletal pathology in patients post Roux-en-Y gastric bypass.

A Retrospective Comparative Study of Primary Versus Revisional Roux-en-Y Gastric Bypass: Long-Term Results.

PubMed

Dardamanis, Dimitrios; Navez, Julie; Coubeau, Laurent; Navez, Benoit

2018-03-09

To compare the perioperative parameters and excess weight loss between patients operated by laporoscopic Roux-en-Y gastric bypass (LRYGB), as a primary operation or a revisional, for insufficient weight loss after vertical banded gastroplasty (VBG) or adjustable gastric banding (AGB). A retrospective analysis of all patients who underwent a LRYGB was performed for the period 2004-2011. Demographics, preoperative body mass index (BMI), co-morbidities, operation time, conversion rate, perioperative complications, hospitalization period, and % of excess BMI loss (%EBMIL) were investigated and compared between groups. Three hundred forty-two laparoscopic gastric bypass operations were performed, 245 were primary, and 97 revisional. Median follow-up was 30 months (range 0-108 months). Mean BMI (kg/m 2 ) before bypass was 45.2 for primary laparoscopic Roux-en-Y gastric bypass (pLRYGB) and 41.1 for revisional laparoscopic Roux-en-Y gastric bypass (rLRYGB). Median operative time and length of stay were longer for rLRYGB 157.5 versus 235 min (p < 0.001) and 6 versus 6.5 days (p = 0.05). Conversion to laparotomy was performed in eight patients, 0.4% of primary and 7.2% of revisional. Morbidity rate was 6.5% in pLRYGB versus 10% in rLRYGB (NS). There was one death in the primary group. Percentage of EBMIL was significantly lower in the revisional group at 12, 18, and 24 months of follow-up. Revisional and primary gastric bypass have no statistical differences in terms of morbidity. The % of excess BMI loss is lower after revisional gastric bypass during the first 2 years of follow-up. The trend of weight loss or weight regain was similar in both groups.

Posttraumatic growth in post-surgical coronary artery bypass graft patients

PubMed Central

Waight, Catherine A; Sheridan, Judith; Tesar, Peter

2015-01-01

Recent research in posttraumatic growth has been applied to people with life-threatening illnesses to optimise recovery. There is a lack of research exploring posttraumatic growth in coronary artery bypass graft patients. This article describes the recovery experience of 14 coronary artery bypass graft patients (13 males and 1 female) at their first outpatient review post-surgery. Grounded theory analysis was used to develop a model of distinct and shared pathways to growth depending on whether patients were symptomatic or asymptomatic pre-coronary artery bypass graft. Outcomes of posttraumatic growth in this sample included action-based healthy lifestyle growth and two forms of cognitive growth: appreciation of life and new possibilities. The model of posttraumatic growth developed in this study may be helpful in guiding future research into promoting posttraumatic growth and behaviour change in coronary artery bypass graft patients. PMID:28070351

Photovoltaic module bypass diode encapsulation

NASA Technical Reports Server (NTRS)

Shepard, N. J., Jr.

1983-01-01

The design and processing techniques necessary to incorporate bypass diodes within the module encapsulant are presented. The Semicon PN junction diode cells were selected. Diode junction to heat spreader thermal resistance measurements, performed on a variety of mounted diode chip types and sizes, have yielded values which are consistently below 1 deg C per watt, but show some instability when thermally cycled over the temperature range from -40 to 150 deg C. Three representative experimental modules, each incorporating integral bypass diode/heat spreader assemblies of various sizes, were designed. Thermal testing of these modules enabled the formulation of a recommended heat spreader plate sizing relationship. The production cost of three encapsulated bypass diode/heat spreader assemblies were compared with similarly rated externally mounted packaged diodes. It is concluded that, when proper designed and installed, these bypass diode devices will improve the overall reliability of a terrestrial array over a 20 year design lifetime.

A comparison of hybrid coronary revascularization and off-pump coronary revascularization.

PubMed

Umakanthan, Ramanan; Leacche, Marzia; Gallion, Anna H; Byrne, John G

2013-04-01

Minimally invasive approaches to treat vascular disease have been accruing significant popularity over the last several decades. Due to progressive advances in technology, a variety of techniques are being now utilized in the field of cardiovascular surgery. The objectives of minimally invasive techniques are to curtail operative trauma and minimize perioperative morbidity without decreasing the quality of the treatment. The standard surgical approach for the treatment of coronary artery disease has traditionally been coronary artery bypass grafting surgery via median sternotomy. Off-pump coronary artery bypass grafting surgery offers a less invasive alternative and enables coronary revascularization to be performed without cardiopulmonary bypass. Hybrid coronary revascularization offers an even less invasive option in which minimally invasive direct coronary artery bypass can be combined with percutaneous coronary intervention. In this article, the authors review a recent publication comparing hybrid coronary revascularization and off-pump coronary artery bypass grafting surgery.

Efficacy of aprotinin with various anticoagulant agents in cardiopulmonary bypass.

PubMed

Terrell, M R; Walenga, J M; Koza, M J; Pifarré, R

1996-08-01

Aprotinin has recently been approved for clinical use in cardiopulmonary bypass. Although unfractionated heparin has been the only anticoagulant widely used for cardiopulmonary bypass, disadvantages involving heparin have led to ongoing investigations of alternative anticoagulant agents. The objective of this study was to evaluate the efficacy of aprotinin in combination with other anticoagulant agents, specifically low molecular weight heparin and recombinant hirudin, using a dog model of cardiopulmonary bypass. The blood conservation resulting from the use of aprotinin was observed only with unfractionated heparin. Efficacy of anticoagulation as measured by protein deposits in the bypass circuit filter revealed an unexpected reduction in the quantity of deposits when aprotinin was used in combination with low molecular weight heparin. As alternative anticoagulant agents are sought, the potential benefits of aprotinin in the reduction of operative blood loss must be evaluated independently for each anticoagulant agent.

Preservation of myocardium during coronary artery bypass surgery.

PubMed

Kinoshita, Takeshi; Asai, Tohru

2012-08-01

Myocardial protection aims to prevent reversible post-ischemic cardiac dysfunction (myocardial stunning) and irreversible myocardial cell death (myocardial infarction) that occur as a consequence of myocardial ischemia and/or ischemic-reperfusion injury. Although the mortality rate for isolated coronary artery bypass grafting has been markedly reduced during the past decade, myocardial death, as evidenced by elevation in creatine kinase-myocardial band and/or cardiac troponin, is common. This is ascribed to suboptimal myocardial protection during cardiopulmonary bypass or with off-pump technique, early graft failure, distal embolization, and regional or global myocardial ischemia during surgery. An unmet need in contemporary coronary bypass surgery is to find more effective cardioprotective strategies that have the potential for decreasing the morbidity and mortality associated with suboptimal cardioprotection. In the present review article on myocardial protection in contemporary coronary artery bypass surgery, we attempt to elucidate the clinical problems, summarize the outcomes of selected phase III trials, and introduce new perspectives.

Fuel cell system shutdown with anode pressure control

DOEpatents

Clingerman, Bruce J.; Doan, Tien M.; Keskula, Donald H.

2002-01-01

A venting methodology and pressure sensing and vent valving arrangement for monitoring anode bypass valve operating during the normal shutdown of a fuel cell apparatus of the type used in vehicle propulsion systems. During a normal shutdown routine, the pressure differential between the anode inlet and anode outlet is monitored in real time in a period corresponding to the normal closing speed of the anode bypass valve and the pressure differential at the end of the closing cycle of the anode bypass valve is compared to the pressure differential at the beginning of the closing cycle. If the difference in pressure differential at the beginning and end of the anode bypass closing cycle indicates that the anode bypass valve has not properly closed, a system controller switches from a normal shutdown mode to a rapid shutdown mode in which the anode inlet is instantaneously vented by rapid vents.

Yolo Bypass Juvenile Salmon Utilization Study 2016—Summary of acoustically tagged juvenile salmon and study fish release, Sacramento River, California

USGS Publications Warehouse

Liedtke, Theresa L.; Hurst, William R.

2017-09-12

The Yolo Bypass is a flood control bypass in Sacramento Valley, California. Flood plain habitats may be used for juvenile salmon rearing, however, the potential value of such habitats can be difficult to evaluate because of the intermittent nature of inundation events. The Yolo Bypass Juvenile Salmon Utilization Study (YBUS) used acoustic telemetry to evaluate the movements and survival of juvenile salmon adjacent to and within the Yolo Bypass during the winter of 2016. This report presents numbers, size data, and release data (times, dates, and locations) for the 1,197 acoustically tagged juvenile salmon released for the YBUS from February 21 to March 18, 2016. Detailed descriptions of the surgical implantation of transmitters are also presented. These data are presented to support the collaborative, interagency analysis and reporting of the study findings.

Use of a tubed pectoralis major myocutaneous flap for salvage of a failed colonic bypass of the esophagus.

PubMed

Doberneck, R C; Oschwald, D L; Orgel, M G

1986-05-01

The use of tube PMCF as salvage for a failed colon bypass of the esophagus has not been described previously. The present report describes the technique and successful use of a tubed PMCF as a solution to the problem of a failed cervical anastomosis after colon bypass of a long distal esophageal stricture.

Ultra High Bypass Integrated System Test

NASA Image and Video Library

2015-09-14

NASA’s Environmentally Responsible Aviation Project, in collaboration with the Federal Aviation Administration (FAA) and Pratt & Whitney, completed testing of an Ultra High Bypass Ratio Turbofan Model in the 9’ x 15’ Low Speed Wind Tunnel at NASA Glenn Research Center. The fan model is representative of the next generation of efficient and quiet Ultra High Bypass Ratio Turbofan Engine designs.

75 FR 27491 - Airworthiness Directives; Pratt & Whitney Canada Corp. PW617F-E Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-17

.... Investigation showed that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that... Fuel Filter Bypass Valve poppet in the FOHE on that engine had worn through the housing seat, allowing.... PW600-72-A66021 that introduced a new fuel Filter Bypass Valve Assembly with an improved design poppet...

(Updated) NCI Fiscal 2016 Bypass Budget Proposes $25 Million for Frederick National Lab | Poster

Cancer.gov

By Nancy Parrish, Staff Writer; image by Richard Frederickson, Staff Photographer The additional funding requested for Frederick National Laboratory for Cancer Research (FNLCR) in the Fiscal 2016 Bypass Budget was $25 million, or approximately 3.5 percent of the total additional funding request of $715 million. Officially called the Professional Judgment Budget, the Bypass

40 CFR Table 37 to Subpart Uuu of... - Requirements for Performance Tests for Bypass Lines

Code of Federal Regulations, 2010 CFR

2010-07-01

... Bypass Lines 37 Table 37 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION...: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Pt. 63, Subpt. UUU, Table 37 Table 37 to Subpart UUU of Part 63—Requirements for Performance Tests for Bypass Lines As stated in § 63...

40 CFR Table 36 to Subpart Uuu of... - Work Practice Standards for HAP Emissions From Bypass Lines

Code of Federal Regulations, 2011 CFR

2011-07-01

... Emissions From Bypass Lines 36 Table 36 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL... Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Pt. 63, Subpt. UUU, Table 36 Table 36 to Subpart UUU of Part 63—Work Practice Standards for HAP Emissions From Bypass Lines...

40 CFR Table 37 to Subpart Uuu of... - Requirements for Performance Tests for Bypass Lines

Code of Federal Regulations, 2011 CFR

2011-07-01

... Bypass Lines 37 Table 37 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION...: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Pt. 63, Subpt. UUU, Table 37 Table 37 to Subpart UUU of Part 63—Requirements for Performance Tests for Bypass Lines As stated in § 63...

40 CFR Table 36 to Subpart Uuu of... - Work Practice Standards for HAP Emissions From Bypass Lines

Code of Federal Regulations, 2010 CFR

2010-07-01

... Emissions From Bypass Lines 36 Table 36 to Subpart UUU of Part 63 Protection of Environment ENVIRONMENTAL... Refineries: Catalytic Cracking Units, Catalytic Reforming Units, and Sulfur Recovery Units Pt. 63, Subpt. UUU, Table 36 Table 36 to Subpart UUU of Part 63—Work Practice Standards for HAP Emissions From Bypass Lines...

By-Pass Diode Temperature Tests of a Solar Array Coupon under Space Thermal Environment Conditions

NASA Technical Reports Server (NTRS)

Wright, Kenneth H.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie; Wu, Gordon

2016-01-01

By-Pass diodes are a key design feature of solar arrays and system design must be robust against local heating, especially with implementation of larger solar cells. By-Pass diode testing was performed to aid thermal model development for use in future array designs that utilize larger cell sizes that result in higher string currents. Testing was performed on a 56-cell Advanced Triple Junction solar array coupon provided by SSL. Test conditions were vacuum with cold array backside using discrete by-pass diode current steps of 0.25 A ranging from 0 A to 2.0 A.

Evaluation of a Stirling engine heater bypass with the NASA Lewis nodal-analysis performance code

NASA Technical Reports Server (NTRS)

Sullivan, T. J.

1986-01-01

In support of the U.S. Department of Energy's Stirling Engine Highway Vehicle Systems program, the NASA Lewis Research Center investigated whether bypassing the P-40 Stirling engine heater during regenerative cooling would improve engine performance. The Lewis nodal-analysis Stirling engine computer simulation was used for this investigation. Results for the heater-bypass concept showed no significant improvement in the indicated thermal efficiency for the P-40 Stirling engine operating at full-power and part-power conditions. Optimizing the heater tube length produced a small increase in the indicated thermal efficiency with the heater-bypass concept.

An animal model for instructing and the study of in situ arterial bypass.

PubMed

Saifi, J; Chang, B B; Paty, P S; Kaufman, J; Leather, R P; Shah, D M

1990-11-01

A canine model that used the cephalic vein to bypass from the brachial to the ulnar artery was designed for use in instructing and evaluating surgical technique needed for constructing an in situ arterial bypass. This model was used for instructing vascular residents in the in situ vein bypass technique. The use of this model enabled the resident to become more adept with the instruments for valve incision and construction of small vessel anastomosis. The improvement in the resident's operative technique was reflected by a decrease in the number of technical complications (missed valves, missed arteriovenous fistulas, poorly constructed anastomoses) and improved patency rate.

Force and Pressure Recovery Characteristics at Supersonic Speeds of a Conical Spike Inlet with a Bypass Discharging from the Top or Bottom of the Diffuser in an Axial Direction

NASA Technical Reports Server (NTRS)

Allen, J L; Beke, Andrew

1953-01-01

Force and pressure-recovery characteristics of a nacelle-type conical-spike inlet with a fixed-area bypass located in the top or bottom of the diffuser are presented for flight Mach numbers of 1.6, 1.8, and 2.0 for angles of attack from 0 degrees to 9 degrees. Top or bottom location of the bypass did not have significant effects on diffuser pressure-recovery, bypass mass-flow ratio, or drag coefficient over the range of angles of attack, flight Mach numbers, and stable engine mass-flow ratios investigated. A larger stable subcritical operating range was obtained with the bypass on the bottom at angles of attack from 3 degrees to 9 degrees at a flight Mach number of 2.0. At a flight Mach number of 2.0, the discharge of 14 percent of the critical mass flow of the inlet by means of a bypass increased the drag only one-fifth of the additive drag that would result for equivalent spillage behind an inlet normal shock without significant reductions in diffuser pressure recovery.

Milrinone, a phosphodiesterase III inhibitor, prevents reduction of jugular bulb saturation during rewarming from hypothermic cardiopulmonary bypass.

PubMed

Iritakenishi, T; Hayashi, Y; Yamanaka, H; Kamibayashi, T; Ueda, K; Mashimo, T

2012-01-01

Inadequate cerebral oxygen balance during cardiopulmonary bypass may cause neuropsychological dysfunction. Milrinone, a phosphodiesterase III inhibitor, augments cerebral blood flow by direct vasodilatation. We conducted a prospective, randomized study in patients undergoing cardiac surgery with cardiopulmonary bypass to clarify the clinical efficacy of milrinone in the imbalance of cerebral oxygen supply and demand during the rewarming period of cardiopulmonary bypass. This is a prospective, randomized and placebo-controlled study. After anesthesia, a 5.5 F fiberoptic oximeter catheter was inserted into the right jugular bulb retrogradely for monitoring the jugular venous oxyhemoglobin saturation (SjO(2)). Patients were randomly assigned to two groups, one receiving a continuous infusion of milrinone, 0.5 µg/kg/min during hypothermic cardiopulmonary bypass, and the other receiving saline as control. Milrinone significantly prevented the reduction of the jugular venous oxyhemoglobin saturation at 10 minutes from the start of rewarming compared with the control group, but did not do so from 10 to 20 minutes after rewarming. Milrinone suppresses the reduction of SjO(2) and improves the balance of cerebral oxygen supply and demand during the early rewarming period of hypothermic cardiopulmonary bypass.

Surgical management for achalasia after coronary artery bypass graft using the right gastroepiploic artery: a case report.

PubMed

Muranushi, Ryo; Miyazaki, Tatsuya; Saito, Hideyuki; Kuriyama, Kengo; Yoshida, Tomonori; Kumakura, Yuji; Honjyo, Hiroaki; Yokobori, Takehiko; Sakai, Makoto; Sohda, Makoto; Kuwano, Hiroyuki

2017-12-01

The right gastroepiploic artery is commonly used in coronary artery bypass grafting. Appropriate strategies are required when performing upper abdominal surgeries after the right gastroepiploic artery has been used in coronary artery bypass grafting because compressing or injuring the graft may cause myocardial ischemia and fatal arrhythmias. To our knowledge, this is the first reported case of surgery for achalasia performed after coronary artery bypass grafting using the right gastroepiploic artery. We have discussed the surgical procedure and particular intraoperative considerations. A 62-year-old man who had undergone coronary artery bypass grafting using the right gastroepiploic artery presented with achalasia. Because medication and balloon dilation had been ineffective and he was having difficulty ingesting food, we performed a Heller-Dor procedure via laparotomy. The right gastroepiploic artery was not damaged during this surgery, and there were no perioperative cardiovascular complications. Adequate control of symptoms was achieved. When performing upper abdominal surgeries after coronary artery bypass grafting with the right gastroepiploic artery, it is necessary to investigate the patient carefully preoperatively and adapt the intraoperative procedure to minimize risk of injury to the graft and consequent cardiovascular complications.

Aortocoronary bypass in Jehovah's Witnesses: review of 46 patients.

PubMed

Sandiford, F M

1976-01-01

The hemodilution technique for cardiopulmonary bypass using blood substitutes for priming has permitted open heart operations in Jehovah's Witnesses who refuse to accept blood, and has reduced the need for massive blood transfusion in certain procedures including aortocoronary bypass. A series of 46 Jehovah's Witness patients underwent aortocoronary bypass procedures. Of these, two patients died, representing a mortality of 4.3 per cent. Neither patient's death was related to lack of blood transfusions. The hospital stay and recovery time of all the other patients was not affected by failure to transfuse blood. The excellent short- and long-term results of this particular group paralleled those observed in our larger series of over 2700 other patients who have undergone coronary bypass surgery since 1969. Among these patients not of the Jehovah's Witness religion, blood transfusion was not necessary in about 30 per cent, while the remainder averaged less than two units per patient. Our results with Jehovah's Witness patients encourage our policy of avoiding blood transfusions whenever possible in all operations. Further justification for our conservative attitude is provided by the current shortage of blood in relation to a projected continuous increase of aortocoronary bypass procedures in the future.

Hyperammonemic syndrome after Roux-en-Y gastric bypass.

PubMed

Fenves, Andrew Z; Shchelochkov, Oleg A; Mehta, Ankit

2015-04-01

Hyperammonemic encephalopathy is an uncommon but severe complication of the Roux-en-Y gastric bypass surgery for obesity. Mechanisms underlying this complication are incompletely understood, resulting in delayed recognition and management. This study evaluated common laboratory findings and possible etiology of hyperammonemic encephalopathy after successful Roux-en-Y gastric bypass surgery. A retrospective review of 20 patients identified through our own clinical practice was conducted, with the addition of similar cases from other institutions identified through the review of literature. Patients presenting with hyperammonemic encephalopathy after Roux-en-Y gastric bypass surgery presented with overlapping clinical and laboratory findings. Common features included: (1) weight loss following successful Roux-en-Y gastric bypass for obesity; (2) hyperammonemic encephalopathy accompanied by elevated plasma glutamine levels; (3) absence of cirrhosis; (4) hypoalbuminemia; and (5) low plasma zinc levels. The mortality rate was 50%. Ninety-five percent of patients were women. Three patients were diagnosed with proximal urea cycle disorders. One patient experienced improvement in the hyperammonemia after surgical correction of spontaneous splenorenal shunt. Hyperammonemic encephalopathy after Roux-en-Y gastric bypass surgery is a newly recognized, potentially fatal syndrome with diverse pathophysiologic mechanisms encompassing genetic and nongenetic causes. © 2015 The Obesity Society.

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

Wu, H.L.; Spronsen, G. van; Klaus, E.H.

A simulation model of the dynamics of a by-pass pig and related two-phase flow behavior along with field trials of the pig in a dry-gas pipeline have revealed significant gains in use of a by-pass pig in modifying gas and liquid production rates. The method can widen the possibility of applying two-phase flow pipeline transportation to cases in which separator or slug-catcher capacity is limited by practicality or cost. Pigging two-phase pipelines normally generates large liquid slug volumes in front of the pig. These require large separators or slug catchers. Using a high by-pass pig to disperse the liquid andmore » reduce the maximum liquid production rate before pig arrival has been investigated by Shell Exploration and Production companies. A simulation model of the dynamics of the pig and related two-phase flow behavior in the pipeline was used to predict the performance of by-pass pigs. Field trials in a dry-gas pipeline were carried out to provide friction data and to validate the model. The predicted mobility of the high by-pass pig in the pipeline and risers was verified and the beneficial effects due to the by-pass concept exceeded the prediction of the simplified model.« less

Postoperative Hydrocortisone Infusion Reduces the Prevalence of Low Cardiac Output Syndrome After Neonatal Cardiopulmonary Bypass.

PubMed

Robert, Stephen M; Borasino, Santiago; Dabal, Robert J; Cleveland, David C; Hock, Kristal M; Alten, Jeffrey A

2015-09-01

Neonatal cardiac surgery with cardiopulmonary bypass is often complicated by morbidity associated with inflammation and low cardiac output syndrome. Hydrocortisone "stress dosing" is reported to provide hemodynamic benefits in some patients with refractory shock. Development of cardiopulmonary bypass-induced adrenal insufficiency may provide further rationale for postoperative hydrocortisone administration. We sought to determine whether prophylactic, postoperative hydrocortisone infusion could decrease prevalence of low cardiac output syndrome after neonatal cardiac surgery with cardiopulmonary bypass. Double-blind, randomized control trial. Pediatric cardiac ICU and operating room in tertiary care center. Forty neonates undergoing cardiac surgery with cardiopulmonary bypass were randomized (19 hydrocortisone and 21 placebo). Demographics and known risk factors were similar between groups. After cardiopulmonary bypass separation, bolus hydrocortisone (50 mg/m²) or placebo was administered, followed by continuous hydrocortisone infusion (50 mg/m²/d) or placebo tapered over 5 days. Adrenocorticotropic hormone stimulation testing (1 μg) was performed before and after cardiopulmonary bypass, prior to steroid administration. Blood was collected for cytokine analysis before and after cardiopulmonary bypass. Subjects receiving hydrocortisone were less likely to develop low cardiac output syndrome (5/19, 26% vs 12/21, 57%; p = 0.049). Hydrocortisone group had more negative net fluid balance at 48 hours (-114 vs -64 mL/kg; p = 0.01) and greater urine output at 0-24 hours (2.7 vs 1.2 mL/kg/hr; p = 0.03). Hydrocortisone group weaned off catecholamines and vasopressin sooner than placebo, with a difference in inotrope-free subjects apparent after 48 hours (p = 0.033). Five placebo subjects (24%) compared with no hydrocortisone subjects required rescue steroids (p = 0.02). Thirteen (32.5%) had adrenal insufficiency after cardiopulmonary bypass. Patients with adrenal insufficiency randomized to receive hydrocortisone had lower prevalence of low cardiac output syndrome compared with patients with adrenal insufficiency randomized to placebo (1/6 vs 6/7, respectively; p = 0.02). Hydrocortisone significantly reduced proinflammatory cytokines. Ventilator-free days, hospital length of stay, and kidney injury were similar. Prophylactic, postoperative hydrocortisone reduces low cardiac output syndrome, improves fluid balance and urine output, and attenuates inflammation after neonatal cardiopulmonary bypass surgery. Further studies are necessary to show if these benefits lead to improvements in more important clinical outcomes.

Hybrid Endovascular Aortic Aneurysm Repair: Preservation of Pelvic Perfusion with External to Internal Iliac Artery Bypass.

PubMed

Mansukhani, Neel A; Havelka, George E; Helenowski, Irene B; Rodriguez, Heron E; Hoel, Andrew W; Eskandari, Mark K

2017-07-01

Diminished pelvic arterial flow as a result of intentional coverage/embolization of internal iliac arteries (IIA) during isolated endovascular common iliac artery aneurysm (CIAA) repair or endovascular repair of abdominal aortic aneurysms (EVAR) may result in symptomatic pelvic ischemia. Although generally well tolerated, in severe cases, pelvic ischemia may manifest as recalcitrant buttock claudication, vasculogenic impotence, or perineal, vesicle, rectal, and/or spinal cord ischemia. Branched graft technology has recently become available; however, many patients are not candidates for endovascular repair with these devices. Therefore, techniques to preserve pelvic arterial flow are needed. We reviewed our outcomes of isolated endovascular CIAA repair or EVAR in conjunction with unilateral external-internal iliac artery bypass. Single-center, retrospective review of 10 consecutive patients who underwent hybrid endovascular abdominal aortic aneurysm (AAA) or CIAA repair with concomitant external-internal iliac artery bypass between 2006 and 2015. Demographics, index procedural details, postoperative symptoms, hospital length of stay (LOS), follow-up imaging, and bypass patency were recorded. The cohort of 10 patients was all men with a mean age of 71 years (range: 56-84). Hybrid repair consisted of contralateral IIA coil embolization followed by EVAR with external iliac artery-internal iliac artery (EIA-IIA) bypass. All EIA-IIA bypasses were performed via a standard lower quadrant retroperitoneal approach with a prosthetic bypass graft. Technical success was 100%, and there were no perioperative deaths. One patient developed transient paraplegia, 1 patient had buttock claudication on the side of his hypogastric embolization contralateral to his iliac bypass, and 1 developed postoperative impotence. 20% of patients sustained long-term complications (buttock claudication and postoperative impotence). Mean LOS was 2.8 days (range: 1-9 days). Postoperative imaging was obtained in 90% of patients, and mean follow-up was 10.8 months (range: 0.5-36 months). All bypasses remained patent. Although branched graft technology continues to evolve, strategies to maintain adequate pelvic circulation are necessary to avoid the devastating complications of pelvic ischemia. We have demonstrated that a hybrid approach combining EVAR or isolated endovascular common iliac artery exclusion with a unilateral external-internal iliac bypass via a retroperitoneal approach is well tolerated with a short LOS and excellent patency rates. Copyright © 2017 Elsevier Inc. All rights reserved.

Investigation on the Core Bypass Flow in a Very High Temperature Reactor

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

Hassan, Yassin

2013-10-22

Uncertainties associated with the core bypass flow are some of the key issues that directly influence the coolant mass flow distribution and magnitude, and thus the operational core temperature profiles, in the very high-temperature reactor (VHTR). Designers will attempt to configure the core geometry so the core cooling flow rate magnitude and distribution conform to the design values. The objective of this project is to study the bypass flow both experimentally and computationally. Researchers will develop experimental data using state-of-the-art particle image velocimetry in a small test facility. The team will attempt to obtain full field temperature distribution using racksmore » of thermocouples. The experimental data are intended to benchmark computational fluid dynamics (CFD) codes by providing detailed information. These experimental data are urgently needed for validation of the CFD codes. The following are the project tasks: • Construct a small-scale bench-top experiment to resemble the bypass flow between the graphite blocks, varying parameters to address their impact on bypass flow. Wall roughness of the graphite block walls, spacing between the blocks, and temperature of the blocks are some of the parameters to be tested. • Perform CFD to evaluate pre- and post-test calculations and turbulence models, including sensitivity studies to achieve high accuracy. • Develop the state-of-the art large eddy simulation (LES) using appropriate subgrid modeling. • Develop models to be used in systems thermal hydraulics codes to account and estimate the bypass flows. These computer programs include, among others, RELAP3D, MELCOR, GAMMA, and GAS-NET. Actual core bypass flow rate may vary considerably from the design value. Although the uncertainty of the bypass flow rate is not known, some sources have stated that the bypass flow rates in the Fort St. Vrain reactor were between 8 and 25 percent of the total reactor mass flow rate. If bypass flow rates are on the high side, the quantity of cooling flow through the core may be considerably less than the nominal design value, causing some regions of the core to operate at temperatures in excess of the design values. These effects are postulated to lead to localized hot regions in the core that must be considered when evaluating the VHTR operational and accident scenarios.« less

Systemic venous drainage: can we help Newton?

PubMed

Corno, Antonio F

2007-06-01

In recent years substantial progress occurred in the techniques of cardiopulmonary bypass, but the factor potentially limiting the flexibility of cardiopulmonary bypass remains the drainage of the systemic venous return. In the daily clinical practice of cardiac surgery, the amount of systemic venous return on cardiopulmonary bypass is directly correlated with the amount of the pump flow. As a consequence, the pump flow is limited by the amount of venous return that the pump is receiving. On cardiopulmonary bypass the amount of venous drainage depends upon the central venous pressure, the height differential between patient and inlet of the venous line into the venous reservoir, and the resistance in the venous cannula(s) and circuit. The factors determining the venous return to be taken into consideration in cardiac surgery are the following: (a) characteristics of the individual patient; (b) type of planned surgical procedure; (c) type of venous cannula(s); (d) type of circuit for cardiopulmonary bypass; (e) strategy of cardiopulmonary bypass; (f) use of accessory mechanical systems to increased the systemic venous return. The careful pre-operative evaluation of all the elements affecting the systemic venous drainage, including the characteristics of the individual patient and the type of required surgical procedure, the choice of the best strategy of cardiopulmonary bypass, and the use of the most advanced materials and tools, can provide a systemic venous drainage substantially better than what it would be allowed by the simple "Law of universal gravitation" by Isaac Newton.

A Delphi Consensus of the Crucial Steps in Gastric Bypass and Sleeve Gastrectomy Procedures in the Netherlands.

PubMed

Kaijser, Mirjam A; van Ramshorst, Gabrielle H; Emous, Marloes; Veeger, Nic J G M; van Wagensveld, Bart A; Pierie, Jean-Pierre E N

2018-04-09

Bariatric procedures are technically complex and skill demanding. In order to standardize the procedures for research and training, a Delphi analysis was performed to reach consensus on the practice of the laparoscopic gastric bypass and sleeve gastrectomy in the Netherlands. After a pre-round identifying all possible steps from literature and expert opinion within our study group, questionnaires were send to 68 registered Dutch bariatric surgeons, with 73 steps for bypass surgery and 51 steps for sleeve gastrectomy. Statistical analysis was performed to identify steps with and without consensus. This process was repeated to reach consensus of all necessary steps. Thirty-eight participants (56%) responded in the first round and 32 participants (47%) in the second round. After the first Delphi round, 19 steps for gastric bypass (26%) and 14 for sleeve gastrectomy (27%) gained full consensus. After the second round, an additional amount of 10 and 12 sub-steps was confirmed as key steps, respectively. Thirteen steps in the gastric bypass and seven in the gastric sleeve were deemed advisable. Our expert panel showed a high level of consensus expressed in a Cronbach's alpha of 0.82 for the gastric bypass and 0.87 for the sleeve gastrectomy. The Delphi consensus defined 29 steps for gastric bypass and 26 for sleeve gastrectomy as being crucial for correct performance of these procedures to the standards of our expert panel. These results offer a clear framework for the technical execution of these procedures.

Detection of imminent vein graft occlusion: what is the optimal surveillance program?

PubMed

Tinder, Chelsey N; Bandyk, Dennis F

2009-12-01

The prediction of infrainguinal vein bypass failure remains an inexact judgment. Patient demographics, technical factors, and vascular laboratory graft surveillance testing are helpful in identifying a high-risk graft cohort. The optimal surveillance program to detect the bypass at risk for imminent occlusion continues to be developed, but required elements are known and include clinical assessment for new or changes in limb ischemia symptoms, measurement of ankle and/or toe systolic pressure, and duplex ultrasound imaging of the bypass graft. Duplex ultrasound assessment of bypass hemodynamics may be the most accurate method to detect imminent vein graft occlusion. The finding of low graft flow during intraoperative assessment or at a scheduled surveillance study predicts failure; and if associated with an occlusive lesion, a graft revision can prolong patency. The most common abnormality producing graft failure is conduit stenosis caused by myointimal hyperplasia; and the majority can be repaired by an endovascular intervention. Frequency of testing to detect the failing bypass should be individualized to the patient, the type of arterial bypass, and prior duplex ultrasound scan findings. The focus of surveillance is on identification of the low-flow arterial bypass and timely repair of detected critical stenosis defined by duplex velocity spectra criteria of a peak systolic velocity 300 cm/s and peak systolic velocity ratio across the stenosis >3.5-correlating with >70% diameter-reducing stenosis. When conducted appropriately, a graft surveillance program should result in an unexpected graft failure rate of <3% per year.

Occipital Artery to Middle Cerebral Artery Bypass in Cases of Unavailable Superficial Temporal Artery.

PubMed

Hirano, Tsukasa; Mikami, Takeshi; Suzuki, Hime; Hirano, Toru; Kimura, Yusuke; Komatsu, Katusya; Akiyama, Yukinori; Wanibuchi, Masahiko; Mikuni, Nobuhiro

2018-04-01

In neurosurgery, extracranial-to-intracranial (EC-IC) bypass surgery is necessary for patients who have undergone surgery in which the superficial temporal artery (STA) was already used for a different bypass procedure or was damaged. Here we report our experience with EC-IC bypass using the occipital artery (OA) in patients in whom the STA was unavailable, and discuss the technical considerations and pitfalls. Five patients with ischemic-onset moyamoya disease and atherosclerotic disease were included. Two patterns of skin incisions were planned according to the OA pathway and recipient artery location. In one of these methods, a skin incision is made above the OA, and a craniotomy is performed under this incision after OA dissection. In the other method, a skin incision is made above the OA to enable its dissection, and a craniotomy is performed via a separate skin incision. No major perioperative complications developed in any of the 5 cases, and bypass patency was confirmed in all patients. There was a significant difference between the preoperative and postoperative asymmetry ratios of the mean transit time values. Our findings suggest that OA-to-middle cerebral artery (MCA) bypass is a simple and effective technique in patients in whom the STA was already used or was damaged by previous intracranial revascularization or craniotomy. This procedure could be an alternative to STA-MCA bypass in patients without an available STA. Copyright © 2018 Elsevier Inc. All rights reserved.

Cerebroprotective effect of piracetam in patients undergoing coronary bypass burgery.

PubMed

Holinski, Sebastian; Claus, Benjamin; Alaaraj, Nour; Dohmen, Pascal Maria; Kirilova, Kremena; Neumann, Konrad; Uebelhack, Ralf; Konertz, Wolfgang

2008-11-01

Reduction of cognitive function is a possible side effect after cardiac surgery using cardiopulmonary bypass. We investigated the cerebroprotective effect of piracetam on cognitive performance in patients undergoing coronary artery bypass surgery under cardiopulmonary bypass. Patients scheduled for elective, primary and isolated coronary bypass surgery were randomised either to piracetam or placebo group. The study was performed in a double blind fashion. Patients received either 12 g piracetam or placebo at the beginning of the operation. Six neuropsychological subtests from the Syndrom Kurz Test and the Alzheimer's Disease Assessment Scale were performed preoperatively and on the third postoperative day. To assess the overall cognitive function and the degree of cognitive decline across all tests after surgery we combined the six test-scores by principal component analysis. A total number of 120 patients were enrolled into the study. Preoperative overall cognitive function were not significantly different between the groups. The postoperative combined score of the neuropsychological tests showed a deterioration of cognitive function in both groups (placebo-pre: -0.06+/-0.99 vs placebo-post: -1.38+/-1.11; p<0.0005 and piracetam-pre: 0.06+/-1.02 vs piracetam-post: -0.65+/-0.93; p<0.0005). However, the piracetam patients performed significantly better compared to the placebo patients after the operation and had a less decline of overall cognitive function (p<0.0005). Piracetam has a cerebroprotective effect in patients undergoing coronary artery bypass surgery with the use of cardiopulmonary bypass. It reduces an early postoperative substantial decline of neuropsychological abilities.

Unilateral Trans-cerebellomedullary Fissure Approach for Occipital Artery to Posterior Inferior Cerebellar Artery Bypass during Aneurysmal Surgery.

PubMed

Abe, Hiroshi; Miki, Koichi; Kobayashi, Hiromasa; Ogata, Toshiyasu; Iwaasa, Mitsutoshi; Matsushima, Toshio; Inoue, Tooru

2017-06-15

Occipital artery (OA) to the posterior inferior cerebellar artery (PICA) bypass is indispensable for the management of complex aneurysms of the PICA that cannot be reconstructed with surgical clipping or coil embolization. Although OA-PICA bypass is a comparatively standard procedure, the bypass is difficult to perform in some cases because of the location and situation of the PICA. We describe the usefulness of the unilateral trans-cerebellomedullary fissure (CMF) approach for OA-PICA bypass. Thirty patients with aneurysms in the vertebral artery (VA) or PICA were treated using OA-PICA bypasses between 2010 and 2015. Among them, the unilateral trans-CMF approach was used for OA-PICA anastomosis in 13 patients. The surgical procedures performed on and the medical records of all the patients were retrospectively reviewed. The unilateral trans-CMF approach was performed for two reasons depending on the PICA location or situation: either because the caudal loop could not be used as a recipient artery because of arterial dissection (3 patients) or because the tonsillo-medullary segment that was located in the upper part of the CMF did not have a caudal loop that was large enough (10 patients). The trans-CMF approach provided a good operative field for the OA-PICA bypass and the anastomosis were successfully performed in all patients. When the recipient artery was located in the upper part of the CMF, the unilateral trans-cerebello-medullary fissure approach provided a sufficient operative field for OA-PICA anastomosis.

Unilateral Trans-cerebellomedullary Fissure Approach for Occipital Artery to Posterior Inferior Cerebellar Artery Bypass during Aneurysmal Surgery

PubMed Central

ABE, Hiroshi; MIKI, Koichi; KOBAYASHI, Hiromasa; OGATA, Toshiyasu; IWAASA, Mitsutoshi; MATSUSHIMA, Toshio; INOUE, Tooru

2017-01-01

Occipital artery (OA) to the posterior inferior cerebellar artery (PICA) bypass is indispensable for the management of complex aneurysms of the PICA that cannot be reconstructed with surgical clipping or coil embolization. Although OA-PICA bypass is a comparatively standard procedure, the bypass is difficult to perform in some cases because of the location and situation of the PICA. We describe the usefulness of the unilateral trans-cerebellomedullary fissure (CMF) approach for OA-PICA bypass. Thirty patients with aneurysms in the vertebral artery (VA) or PICA were treated using OA-PICA bypasses between 2010 and 2015. Among them, the unilateral trans-CMF approach was used for OA-PICA anastomosis in 13 patients. The surgical procedures performed on and the medical records of all the patients were retrospectively reviewed. The unilateral trans-CMF approach was performed for two reasons depending on the PICA location or situation: either because the caudal loop could not be used as a recipient artery because of arterial dissection (3 patients) or because the tonsillo-medullary segment that was located in the upper part of the CMF did not have a caudal loop that was large enough (10 patients). The trans-CMF approach provided a good operative field for the OA-PICA bypass and the anastomosis were successfully performed in all patients. When the recipient artery was located in the upper part of the CMF, the unilateral trans-cerebello-medullary fissure approach provided a sufficient operative field for OA-PICA anastomosis. PMID:28484132

Association of Patient Age at Gastric Bypass Surgery With Long-term All-Cause and Cause-Specific Mortality.

PubMed

Davidson, Lance E; Adams, Ted D; Kim, Jaewhan; Jones, Jessica L; Hashibe, Mia; Taylor, David; Mehta, Tapan; McKinlay, Rodrick; Simper, Steven C; Smith, Sherman C; Hunt, Steven C

2016-07-01

Bariatric surgery is effective in reducing all-cause and cause-specific long-term mortality. Whether the long-term mortality benefit of surgery applies to all ages at which surgery is performed is not known. To examine whether gastric bypass surgery is equally effective in reducing mortality in groups undergoing surgery at different ages. All-cause and cause-specific mortality rates and hazard ratios (HRs) were estimated from a retrospective cohort within 4 categories defined by age at surgery: younger than 35 years, 35 through 44 years, 45 through 54 years, and 55 through 74 years. Mean follow-up was 7.2 years. Patients undergoing gastric bypass surgery seen at a private surgical practice from January 1, 1984, through December 31, 2002, were studied. Data analysis was performed from June 12, 2013, to September 6, 2015. A cohort of 7925 patients undergoing gastric bypass surgery and 7925 group-matched, severely obese individuals who did not undergo surgery were identified through driver license records. Matching criteria included year of surgery to year of driver license application, sex, 5-year age groups, and 3 body mass index categories. Roux-en-Y gastric bypass surgery. All-cause and cause-specific mortality compared between those undergoing and not undergoing gastric bypass surgery using HRs. Among the 7925 patients who underwent gastric bypass surgery, the mean (SD) age at surgery was 39.5 (10.5) years, and the mean (SD) presurgical body mass index was 45.3 (7.4). Compared with 7925 matched individuals not undergoing surgery, adjusted all-cause mortality after gastric bypass surgery was significantly lower for patients 35 through 44 years old (HR, 0.54; 95% CI, 0.38-0.77), 45 through 54 years old (HR, 0.43; 95% CI, 0.30-0.62), and 55 through 74 years old (HR, 0.50; 95% CI, 0.31-0.79; P < .003 for all) but was not lower for those younger than 35 years (HR, 1.22; 95% CI, 0.82-1.81; P = .34). The lack of mortality benefit in those undergoing gastric bypass surgery at ages younger than 35 years primarily derived from a significantly higher number of externally caused deaths (HR, 2.53; 95% CI, 1.27-5.07; P = .009), particularly among women (HR, 3.08; 95% CI, 1.4-6.7; P = .005). Patients undergoing gastric bypass surgery had a significantly lower age-related increase in mortality than severely obese individuals not undergoing surgery (P = .001). Gastric bypass surgery was associated with improved long-term survival for all patients undergoing surgery at ages older than 35 years, with externally caused deaths only elevated in younger women. Gastric bypass surgery is protective against mortality even for older patients and also reduces the age-related increase in mortality observed in severely obese individuals not undergoing surgery.

Outcomes of lower extremity bypass performed for acute limb ischemia

PubMed Central

Baril, Donald T.; Patel, Virendra I.; Judelson, Dejah R.; Goodney, Philip P.; McPhee, James T.; Hevelone, Nathanael D.; Cronenwett, Jack L.; Schanzer, Andres

2013-01-01

Objective Acute limb ischemia remains one of the most challenging emergencies in vascular surgery. Historically, outcomes following interventions for acute limb ischemia have been associated with high rates of morbidity and mortality. The purpose of this study was to determine contemporary outcomes following lower extremity bypass performed for acute limb ischemia. Methods All patients undergoing infrainguinal lower extremity bypass between 2003 and 2011 within hospitals comprising the Vascular Study Group of New England were identified. Patients were stratified according to whether or not the indication for lower extremity bypass was acute limb ischemia. Primary end points included bypass graft occlusion, major amputation, and mortality at 1 year postoperatively as determined by Kaplan-Meier life table analysis. Multivariable Cox proportional hazards models were constructed to evaluate independent predictors of mortality and major amputation at 1 year. Results Of 5712 lower extremity bypass procedures, 323 (5.7%) were performed for acute limb ischemia. Patients undergoing lower extremity bypass for acute limb ischemia were similar in age (66 vs 67; P = .084) and sex (68% male vs 69% male; P = .617) compared with chronic ischemia patients, but were less likely to be on aspirin (63% vs 75%; P < .0001) or a statin (55% vs 68%; P < .0001). Patients with acute limb ischemia were more likely to be current smokers (49% vs 39%; P < .0001), to have had a prior ipsilateral bypass (33% vs 24%; P = .004) or a prior ipsilateral percutaneous intervention (41% vs 29%; P = .001). Bypasses performed for acute limb ischemia were longer in duration (270 vs 244 minutes; P = .007), had greater blood loss (363 vs 272 mL; P < .0001), and more commonly utilized prosthetic conduits (41% vs 33%; P = .003). Acute limb ischemia patients experienced increased in-hospital major adverse events (20% vs 12%; P < .0001) including myocardial infarction, congestive heart failure exacerbation, deterioration in renal function, and respiratory complications. Patients who underwent lower extremity bypass for acute limb ischemia had no difference in rates of graft occlusion (18.1% vs 18.5%; P = .77), but did have significantly higher rates of limb loss (22.4% vs 9.7%; P < .0001) and mortality (20.9% vs 13.1%; P < .0001) at 1 year. On multivariable analysis, acute limb ischemia was an independent predictor of both major amputation (hazard ratio, 2.16; confidence interval, 1.38–3.40; P = .001) and mortality (hazard ratio, 1.41; confidence interval, 1.09–1.83; P = .009) at 1 year. Conclusions Patients who present with acute limb ischemia represent a less medically optimized subgroup within the population of patients undergoing lower extremity bypass. These patients may be expected to have more complex operations followed by increased rates of perioperative adverse events. Additionally, despite equivalent graft patency rates, patients undergoing lower extremity bypass for acute ischemia have significantly higher rates of major amputation and mortality at 1 year. PMID:23714364

Outcomes of lower extremity bypass performed for acute limb ischemia.

PubMed

Baril, Donald T; Patel, Virendra I; Judelson, Dejah R; Goodney, Philip P; McPhee, James T; Hevelone, Nathanael D; Cronenwett, Jack L; Schanzer, Andres

2013-10-01

Acute limb ischemia remains one of the most challenging emergencies in vascular surgery. Historically, outcomes following interventions for acute limb ischemia have been associated with high rates of morbidity and mortality. The purpose of this study was to determine contemporary outcomes following lower extremity bypass performed for acute limb ischemia. All patients undergoing infrainguinal lower extremity bypass between 2003 and 2011 within hospitals comprising the Vascular Study Group of New England were identified. Patients were stratified according to whether or not the indication for lower extremity bypass was acute limb ischemia. Primary end points included bypass graft occlusion, major amputation, and mortality at 1 year postoperatively as determined by Kaplan-Meier life table analysis. Multivariable Cox proportional hazards models were constructed to evaluate independent predictors of mortality and major amputation at 1 year. Of 5712 lower extremity bypass procedures, 323 (5.7%) were performed for acute limb ischemia. Patients undergoing lower extremity bypass for acute limb ischemia were similar in age (66 vs 67; P = .084) and sex (68% male vs 69% male; P = .617) compared with chronic ischemia patients, but were less likely to be on aspirin (63% vs 75%; P < .0001) or a statin (55% vs 68%; P < .0001). Patients with acute limb ischemia were more likely to be current smokers (49% vs 39%; P < .0001), to have had a prior ipsilateral bypass (33% vs 24%; P = .004) or a prior ipsilateral percutaneous intervention (41% vs 29%; P = .001). Bypasses performed for acute limb ischemia were longer in duration (270 vs 244 minutes; P = .007), had greater blood loss (363 vs 272 mL; P < .0001), and more commonly utilized prosthetic conduits (41% vs 33%; P = .003). Acute limb ischemia patients experienced increased in-hospital major adverse events (20% vs 12%; P < .0001) including myocardial infarction, congestive heart failure exacerbation, deterioration in renal function, and respiratory complications. Patients who underwent lower extremity bypass for acute limb ischemia had no difference in rates of graft occlusion (18.1% vs 18.5%; P = .77), but did have significantly higher rates of limb loss (22.4% vs 9.7%; P < .0001) and mortality (20.9% vs 13.1%; P < .0001) at 1 year. On multivariable analysis, acute limb ischemia was an independent predictor of both major amputation (hazard ratio, 2.16; confidence interval, 1.38-3.40; P = .001) and mortality (hazard ratio, 1.41; confidence interval, 1.09-1.83; P = .009) at 1 year. Patients who present with acute limb ischemia represent a less medically optimized subgroup within the population of patients undergoing lower extremity bypass. These patients may be expected to have more complex operations followed by increased rates of perioperative adverse events. Additionally, despite equivalent graft patency rates, patients undergoing lower extremity bypass for acute ischemia have significantly higher rates of major amputation and mortality at 1 year. Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

Phaeochromocytoma presenting with labile blood pressures following coronary artery bypass grafting.

PubMed

Roy, James; Akhunji, Zakir; Kushwaha, Virag; Mackie, James; Jepson, Nigel

2016-12-01

Pheochromocytomas have been reported prior to and during coronary artery bypass surgery. We present a patient with an undiagnosed pheochromocytoma who presented with labile hypertension following coronary artery bypass surgery. This case calls attention to the inclusion of an undiagnosed pheochromocytoma in the differential diagnosis for all patients who develop labile hypertension in the postoperative period following cardiac surgery. © 2016 Wiley Periodicals, Inc.

75 FR 51659 - Airworthiness Directives; Pratt & Whitney Canada Corp. PW617F-E Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-23

... showed that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that engine had... that the Fuel Filter Bypass Valve poppet in the FOHE on that engine had worn through the housing seat... an ASB No. PW600-72-A66021 that introduced a new fuel Filter Bypass Valve Assembly with an improved...

75 FR 51657 - Airworthiness Directives; Pratt & Whitney Canada Corp. (P&WC) PW615F-A Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-23

... showed that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that engine had... a dormant failure that could result in an unsafe condition. The PW615F-A engine Fuel Filter Bypass... that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that engine had worn...

75 FR 27489 - Airworthiness Directives; Pratt & Whitney Canada Corp. PW615F-A Turbofan Engines

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-17

.... Investigation showed that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that...-A engine Fuel Filter Bypass Valve is very similar to that of PW617F-E, but so far there have been no... Fuel Filter Bypass Valve poppet in the FOHE on that engine had worn through the housing seat, allowing...

Bypass diode for a solar cell

DOEpatents

Rim, Seung Bum [Palo Alto, CA; Kim, Taeseok [San Jose, CA; Smith, David D [Campbell, CA; Cousins, Peter J [Menlo Park, CA

2012-03-13

Bypass diodes for solar cells are described. In one embodiment, a bypass diode for a solar cell includes a substrate of the solar cell. A first conductive region is disposed above the substrate, the first conductive region of a first conductivity type. A second conductive region is disposed on the first conductive region, the second conductive region of a second conductivity type opposite the first conductivity type.

Bypassing health facilities for childbirth in the context of the JSY cash transfer program to promote institutional birth: A cross-sectional study from Madhya Pradesh, India

PubMed Central

Sabde, Yogesh; Chaturvedi, Sarika; Randive, Bharat; Sidney, Kristi; Salazar, Mariano; De Costa, Ayesha; Diwan, Vishal

2018-01-01

Bypassing health facilities for childbirth can be costly both for women and health systems. There have been some reports on this from Sub-Saharan African and from Nepal but none from India. India has implemented the Janani Suraksha Yojana (JSY), a large national conditional cash transfer program which has successfully increased the number of institutional births in India. This paper aims to study the extent of bypassing the nearest health facility offering intrapartum care in three districts of Madhya Pradesh, India, and to identify individual and facility determinants of bypassing in the context of the JSY program. Our results provide information to support the optimal utilization of facilities at different levels of the healthcare system for childbirth. Data was collected from 96 facilities (74 public) and 720 rural mothers who delivered at these facilities were interviewed. Multilevel logistic regression was used to analyze the data. Facility obstetric care functionality was assessed by the number of emergency obstetric care (EmOC) signal functions performed in the last three months. Thirty eighth percent of the mothers bypassed the nearest public facility for their current delivery. Primiparity, higher education, arriving by hired transport and a longer distance from home to the nearest facility increased the odds of bypassing a public facility for childbirth. The variance partition coefficient showed that 37% of the variation in bypassing the nearest public facility can be attributed to difference between facilities. The number of basic emergency obstetric care signal functions (AOR = 0.59, 95% CI 0.37–0.93), and the availability of free transportation at the nearest facility (AOR = 0.11, 95% CI 0.03–0.31) were protective factors against bypassing. The variation between facilities (MOR = 3.85) was more important than an individual’s characteristics to explain bypassing in MP. This multilevel study indicates that in this setting, a focus on increasing the level of emergency obstetric care functionality in public obstetric care facilities will allow more optimal utilization of facilities for childbirth under the JSY program thereby leading to better outcomes for mothers. PMID:29385135

Bypassing health facilities for childbirth in the context of the JSY cash transfer program to promote institutional birth: A cross-sectional study from Madhya Pradesh, India.

PubMed

Sabde, Yogesh; Chaturvedi, Sarika; Randive, Bharat; Sidney, Kristi; Salazar, Mariano; De Costa, Ayesha; Diwan, Vishal

2018-01-01

Bypassing health facilities for childbirth can be costly both for women and health systems. There have been some reports on this from Sub-Saharan African and from Nepal but none from India. India has implemented the Janani Suraksha Yojana (JSY), a large national conditional cash transfer program which has successfully increased the number of institutional births in India. This paper aims to study the extent of bypassing the nearest health facility offering intrapartum care in three districts of Madhya Pradesh, India, and to identify individual and facility determinants of bypassing in the context of the JSY program. Our results provide information to support the optimal utilization of facilities at different levels of the healthcare system for childbirth. Data was collected from 96 facilities (74 public) and 720 rural mothers who delivered at these facilities were interviewed. Multilevel logistic regression was used to analyze the data. Facility obstetric care functionality was assessed by the number of emergency obstetric care (EmOC) signal functions performed in the last three months. Thirty eighth percent of the mothers bypassed the nearest public facility for their current delivery. Primiparity, higher education, arriving by hired transport and a longer distance from home to the nearest facility increased the odds of bypassing a public facility for childbirth. The variance partition coefficient showed that 37% of the variation in bypassing the nearest public facility can be attributed to difference between facilities. The number of basic emergency obstetric care signal functions (AOR = 0.59, 95% CI 0.37-0.93), and the availability of free transportation at the nearest facility (AOR = 0.11, 95% CI 0.03-0.31) were protective factors against bypassing. The variation between facilities (MOR = 3.85) was more important than an individual's characteristics to explain bypassing in MP. This multilevel study indicates that in this setting, a focus on increasing the level of emergency obstetric care functionality in public obstetric care facilities will allow more optimal utilization of facilities for childbirth under the JSY program thereby leading to better outcomes for mothers.

Correlation between reduction in microvascular transit time after superficial temporal artery-middle cerebral artery bypass surgery for moyamoya disease and the development of postoperative hyperperfusion syndrome.

PubMed

Yang, Tao; Higashino, Yoshifumi; Kataoka, Hiroharu; Hamano, Eika; Maruyama, Daisuke; Iihara, Koji; Takahashi, Jun C

2018-05-01

OBJECTIVE Hyperperfusion syndrome (HPS) is a notable complication that causes various neurological symptoms after superficial temporal artery (STA)-middle cerebral artery (MCA) bypass surgery for moyamoya disease (MMD). The authors used intraoperative indocyanine green (ICG) videoangiography to measure the change in microvascular transit time (MVTT) after bypass surgery. An analysis was then conducted to identify the correlation between change in MVTT and presence of postoperative HPS. METHODS This study included 105 hemispheres of 81 patients with MMD who underwent STA-MCA single bypass surgery between January 2010 and January 2015. Intraoperative ICG videoangiography was performed before and after bypass surgery. The MVTT was calculated from the ICG time intensity curve recorded in the pial arterioles and venules. Multivariate logistic regression analysis was conducted to test the effect of multiple variables, including the change in MVTT after bypass surgery, on postoperative HPS. RESULTS Postoperative HPS developed in 28 (26.7%) of the 105 hemispheres operated on. MVTT was reduced significantly after bypass surgery (prebypass 5.34 ± 2.00 sec vs postbypass 4.12 ± 1.60 sec; p < 0.001). The difference between prebypass and postbypass MVTT values, defined as ΔMVTT, was significantly greater in the HPS group than in the non-HPS group (2.55 ± 2.66 sec vs 0.75 ± 1.78 sec; p < 0.001). Receiver operating characteristic curve analysis revealed that the optimal cutoff point of ΔMVTT was 2.6 seconds (sensitivity 46.4% and specificity 85.7% as a predictor of postoperative HPS). A ΔMVTT > 2.6 seconds was an independent predictor of HPS in multivariate analysis (hazard ratio 4.88, 95% CI 1.76-13.57; p = 0.002). CONCLUSIONS MVTT in patients with MMD was reduced significantly after bypass surgery. Patients with a ΔMVTT > 2.6 seconds tended to develop postoperative HPS. Because ΔMVTT can be easily measured during surgery, it is a useful diagnostic tool for identifying patients at high risk for HPS after STA-MCA bypass surgery for MMD.

Apico-brachiocephalic artery bypass for aortic stenosis with porcelain aorta.

PubMed

Shimizu, Shuji; Nakai, Mikizo; Itoh, Atsushi; Yoshizumi, Ko; Ochi, Yoshiki; Okada, Masahiro; Sano, Shunji

2010-02-01

Apicoaortic bypass for left ventricular outflow tract obstruction has been performed with acceptable mid-term mortality. However, sometimes it is difficult to anastomose the distal end of the conduit to the calcified descending aorta in patients with a porcelain aorta. We report an aortic non-touch modification of the apicoaortic bypass in an 80-year-old woman with valvular aortic stenosis and a porcelain aorta extending from the ascending to abdominal aorta. We performed apico-brachiocephalic artery bypass under circulatory arrest with deep hypothermia. This procedure may become a useful surgical option for patients with a severe porcelain aorta. 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Volatile anaesthesia during cardiopulmonary bypass.

PubMed

McMullan, V; Alston, R P; Tyrrell, J

2015-01-01

Since its inception, administering and ensuring anaesthesia during cardiopulmonary bypass has been challenging. Partly because of the difficulty of administering volatile agents during cardiopulmonary bypass, total intravenous anaesthesia has been a popular technique used by cardiac anaesthetists in the last two decades. However, the possibility that volatile agents reduce mortality and the incidence of myocardial infarction by preconditioning the myocardium has stimulated a resurgence of interest in their use for cardiac anaesthesia. The aim of this review is to provide an overview of the administration of volatile anaesthetic agents during cardiopulmonary bypass for the maintenance of anaesthesia and to address some of the practical issues that are involved in doing so. © The Author(s) 2014.

Are patients bypassing paediatric cardiology outreach clinics?

PubMed

Fletcher, Alexander; Samson, Ray; McLeod, Karen

2017-07-01

Previous studies have identified that receiving specialist care close to home can positively influence patients' experience. Despite this, a review of cardiology outpatient appointments at the Royal Hospital for Children in Glasgow demonstrated that a large number of families are bypassing their local children's cardiology centre to attend cardiac clinics at the specialist children's surgical centre. We used patient questionnaire, audit of local facilities, and examined the relationship between diagnosis and bypass numbers to better understand factors influencing this trend. Our results suggest that patient preference, short travelling distance to specialist children's cardiac centre, a more severe cardiac diagnosis, and inconsistent local facilities, expertise, and support are likely to influence a family's decision to bypass their local children's cardiology centre.

The use of ultrasound for postoperative monitoring of cerebral bypass grafts: A technical report.

PubMed

Morton, Ryan P; Abecassis, Isaac Joshua; Moore, Anne E; Kelly, Cory M; Levitt, Michael R; Kim, Louis J; Sekhar, Laligam N

2017-06-01

Duplex ultrasound and transcranial Doppler are valuable tools for post-operative monitoring of extracranial-intracranial cerebral bypass grafts. Here we describe our technique for the evaluation of both high-flow and low-flow cerebral bypass grafts over a nine year period. 186 bypass grafts were studied daily during the inpatient period between Jan 2005 and Dec 2014 after surgery for various cerebrovascular pathologies. There was a technical success rate of 97%. Duplex ultrasonographic flow measurements had excellent interobserver reliability with an intraclass correlation coefficient (ICC) of 0.89 (p=0.009). Technical nuances are highlighted and a brief discussion of pathology is undertaken. Copyright © 2017 Elsevier Ltd. All rights reserved.

Endovascular revascularization of diseased native arteries following failed aortoiliac and femoropoliteal grafts: report of two cases.

PubMed

Nishibe, Toshiya; Kondo, Yuka; Dardik, Alan; Muto, Akihito; Koizumi, Jun; Nishibe, Masayasu

2010-02-01

Arterial reconstructions for lower-extremity ischemia, comprising aortoiliac, aortofemoral, and femoropopoliteal bypasses, and other procedures, have an intrinsic tendency to fail as time elapses. Surgical approaches to arteries in patients who have failed bypass grafts are often rendered more difficult, or even impossible to use, by surgical scarring or infection. The authors report two cases in which the diseased native arteries treated with failed aortoiliac and femoropopliteal bypass grafts were successfully recanalized with primary stent placement. Our cases show that stent placement of the diseased native arteries can represent a possible option for the treatment of failed bypass grafts. Copyright (c) 2010 SIR. Published by Elsevier Inc. All rights reserved.

[Prevention of side effects and complications after operation for partial ileal bypass].

PubMed

Mirchuk, K K; Sedletskiĭ, Iu I

2014-01-01

Side effects and complications of the application of partial ileal bypass used for dislipidemia were analyzed in 162 patients with atherosclerosis. It was shown, that the partial ileal bypass operation could lead to the development of series of undesirable side effects such as diarrhea, hypovitaminosis B12, off-state intestine enteritis. The application of modification of partial ileal bypass such as formation of ileo-ileoanastomosis 5-6 cm long near ileocecal valve with the maintenance of its functions disposed the diarrhea and minimized the risk of the development of hypovitaminosis B12 after operation. It is possible to prevent the development of enteritis of off-state loop of the small intestine by using microanastomosis between off-state and functioning iliac intestine. The partial ileal bypass operation didn't influence on body weight, wouldn't increase the risk of stone formation in the gallbladder and kidneys. The risk of the development of hypovitaminosis B12 is minimal after operation.

Bypass surgery to treat symptomatic fusiform dilation of the internal carotid artery following craniopharyngioma resection: report of 2 cases.

PubMed

Wang, Long; Shi, Xiang'en; Liu, Fangjun; Qian, Hai

2016-12-01

Fusiform dilation of the internal carotid artery (FDICA) is an infrequent vascular complication following resection of suprasellar lesions in the pediatric population, and its course appears to be benign without apparent clinical symptoms. However, data correlating symptomatic FDICA with bypass surgery are scarce. The authors here report 2 symptomatic cases that were treated using internal maxillary artery bypass more than 5 years after total removal of a craniopharyngioma at an outside institution. Both cases of FDICA were resected to relieve the mass effect and to expose the craniopharyngioma. The postoperative course was uneventful, and radiological imaging revealed graft conduit patency. To the authors' knowledge, this is the first reported use of extracranial to intracranial bypass to treat FDICA following removal of a suprasellar lesion. Their findings suggest that bypass surgery is a useful therapeutic approach for symptomatic cases of FDICA and total removal of recurrent craniopharyngioma. Moreover, the indications for surgical intervention and treatment modalities are discussed in the context of previous relevant cases.

Active bypass flow control for a seal in a gas turbine engine

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

Ebert, Todd A.; Kimmel, Keith D.

An active bypass flow control system for controlling bypass compressed air based upon leakage flow of compressed air flowing past an outer balance seal between a stator and rotor of a first stage of a gas turbine in a gas turbine engine is disclosed. The active bypass flow control system is an adjustable system in which one or more metering devices may be used to control the flow of bypass compressed air as the flow of compressed air past the outer balance seal changes over time as the outer balance seal between the rim cavity and the cooling cavity wearsmore » In at least one embodiment, the metering device may include an annular ring having at least one metering orifice extending therethrough, whereby alignment of the metering orifice with the outlet may be adjustable to change a cross-sectional area of an opening of aligned portions of the outlet and the metering orifice.« less

Internal to external jugular vein bypass allowing for simultaneous bilateral radical neck dissection.

PubMed

Mourad, Moustafa; Saman, Masoud; Ducic, Yadranko

2015-11-01

The goal of the study was to determine the role of internal jugular vein (IJV) to external jugular vein (EJV) bypass grafting in the setting of bilateral radical neck dissection with IJV sacrifice. The study group consisted of eight patients who underwent bilateral radical neck dissection with IJV sacrifice. Demographic and oncologic parameters were defined for each patient, including age, gender, and pathology. Patients were monitored and evaluated for potential effects of increased intracranial pressure (ICP). Doppler ultrasonic evaluation was performed to assess patency of the site of anastamoses. In all, six patients underwent unilateral bypass grafting, whereas two patients underwent bilateral bypass grafts. Average age at time of surgery was 68.2 (range 56-71). Postoperatively, no sequelae of increased ICP were noted. Follow-up ultrasonic evaluation revealed patent vessels in all patients. We presently report on the use of EJV-to-IJV bypass grafting for all patients undergoing bilateral radical neck dissection for extensive neck disease. 4. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

The Benefits of Photorespiratory Bypasses: How Can They Work?1[OPEN

PubMed Central

Xin, Chang-Peng; Tholen, Danny; Devloo, Vincent; Zhu, Xin-Guang

2015-01-01

Bypassing the photorespiratory pathway is regarded as a way to increase carbon assimilation and, correspondingly, biomass production in C3 crops. Here, the benefits of three published photorespiratory bypass strategies are systemically explored using a systems-modeling approach. Our analysis shows that full decarboxylation of glycolate during photorespiration would decrease photosynthesis, because a large amount of the released CO2 escapes back to the atmosphere. Furthermore, we show that photosynthesis can be enhanced by lowering the energy demands of photorespiration and by relocating photorespiratory CO2 release into the chloroplasts. The conductance of the chloroplast membranes to CO2 is a key feature determining the benefit of the relocation of photorespiratory CO2 release. Although our results indicate that the benefit of photorespiratory bypasses can be improved by increasing sedoheptulose bisphosphatase activity and/or increasing the flux through the bypass, the effectiveness of such approaches depends on the complex regulation between photorespiration and other metabolic pathways. PMID:25516604

Successful percutaneous stenting of a right gastroepiploic coronary bypass graft using monorail delivery system: a case report.

PubMed

Alam, M; Safi, A M; Mandawat, M K; Anderson, J E; Kwan, T; Feit, A; Clark, L T

2000-02-01

The right gastroepiploic artery (RGEA) is being successfully used as an arterial conduit in a selected group of patients undergoing coronary artery bypass graft surgery. However, myocardial ischemia may result due to spasm, occlusion, and stenosis of this graft. The anastamosis site at distal right coronary artery (RCA) or posterior descending artery (PDA) is the most common location for stenosis of an in situ gastroepiploic coronary bypass graft. Balloon angioplasty of such stenoses has been reported with optimal short-term results. Stent deployment would decrease the restenosis rate, so that repeat procedures could be minimized for these technically challenging lesions. We describe a case of successful deployment of a stent with monorail delivery system at the anastamotic site stenosis of an in situ gastroepiploic right coronary artery bypass graft. This percutaneous coronary intervention could prevent redo coronary artery bypass graft surgery. Cathet. Cardiovasc. Intervent. 49:197-199, 2000. Copyright 2000 Wiley-Liss, Inc.

Evaluation of a Novel Laser-assisted Coronary Anastomotic Connector - the Trinity Clip - in a Porcine Off-pump Bypass Model

PubMed Central

Stecher, David; Bronkers, Glenn; Noest, Jappe O.T.; Tulleken, Cornelis A.F.; Hoefer, Imo E.; van Herwerden, Lex A.; Pasterkamp, Gerard; Buijsrogge, Marc P.

2014-01-01

To simplify and facilitate beating heart (i.e., off-pump), minimally invasive coronary artery bypass surgery, a new coronary anastomotic connector, the Trinity Clip, is developed based on the excimer laser-assisted nonocclusive anastomosis technique. The Trinity Clip connector enables simplified, sutureless, and nonocclusive connection of the graft to the coronary artery, and an excimer laser catheter laser-punches the opening of the anastomosis. Consequently, owing to the complete nonocclusive anastomosis construction, coronary conditioning (i.e., occluding or shunting) is not necessary, in contrast to the conventional anastomotic technique, hence simplifying the off-pump bypass procedure. Prior to clinical application in coronary artery bypass grafting, the safety and quality of this novel connector will be evaluated in a long-term experimental porcine off-pump coronary artery bypass (OPCAB) study. In this paper, we describe how to evaluate the coronary anastomosis in the porcine OPCAB model using various techniques to assess its quality. Representative results are summarized and visually demonstrated. PMID:25490000

Diffuse large B-cell lymphoma (DLBCL) in the bypassed stomach after obesity surgery.

PubMed

Courtney, M J; Chattopadhyay, D; Rao, M; Light, D; Gopinath, B

2014-04-01

Laparoscopic Roux-en-Y gastric bypass is the most commonly performed surgical procedure for obesity and, consequently, post-operative patients are increasingly encountered by all specialties. This is a case of a patient presenting with abdominal pain, nausea and fever 9 months following gastric bypass surgery caused by diffuse large B-cell lymphoma (DLBCL) in the bypassed stomach. It demonstrates well that symptoms that may normally be considered 'red-flags' may not be as obvious or specific following an operation. The case also indicates the importance of considering diagnoses unrelated to surgery presenting in the post-operative period (especially when conventional investigation methods are not feasible), and the potential danger of assuming they are due to the operation alone; had this occurred in this patient then a malignancy may have been missed. This is only the second reported case of DLBCL in the bypassed stomach, and the third for lymphoma of any type. © 2014 The Authors. Clinical Obesity © 2014 International Association for the Study of Obesity.

Off-Pump Versus On-Pump Coronary Artery Bypass Grafting-A Systematic Review and Analysis of Clinical Outcomes.

PubMed

Shaefi, Shahzad; Mittel, Aaron; Loberman, Dan; Ramakrishna, Harish

2018-04-04

Surgical coronary artery bypass grafting (CABG) is the standard of care for revascularization of left main or three-vessel coronary artery disease. The off-pump coronary artery bypass graft (OPCAB) procedure avoids the use of cardiopulmonary bypass. Theoretically, OPCAB may improve long-term outcomes by reducing the rates of perioperative myocardial injury, stroke, neurocognitive impairment, and cardiac-related mortality. Several high-quality clinical trials have been conducted since OPCAB became popular in the 1990s and have demonstrated no benefit of OPCAB over traditional CABG with respect to these outcomes despite favorable short-term reductions in transfusion requirements and other postoperative complications. Ultimately, OPCAB is associated with less effective myocardial revascularization and does not entirely prevent complications traditionally associated with cardiopulmonary bypass. This article reviews major high-quality trials of OPCAB versus traditional CABG with respect to both short- and long-term clinical outcomes. Copyright © 2018 Elsevier Inc. All rights reserved.

In situ cephalic vein bypasses from axillary to the brachial artery after catheterization injuries.

PubMed

Hudorovic, Narcis; Lovricevic, Ivo; Ahel, Zaky

2010-07-01

The need to bypass to the brachial artery is rare. Over a five-year period, 16 patients had suffered iatrogenic post-catheterization injuries of the upper extremity. We have performed 16 bypasses, in 16 patients, mean age was 65 years (range 47-75), to the brachial artery originating from an artery proximal to the shoulder joint. In all cases, the axillary artery was the donor artery. All bypasses were created by using the cephalic vein with the in situ technique and distal anastomoses were made to a distance-free section of brachial artery. No operative mortality, neurological complications or major upper-extremity amputation was associated with the procedure. Life-long-conduit analysis showed 75% patency in the five-year period. After iatrogenic post-catheterization trauma of arterial system of upper extremity, bypasses from axillary to brachial artery with the cephalic vein with the in situ technique is a safe operation with satisfactory long-term patency.

Monsanto may bypass NIH in microbe test.

PubMed

Sun, Marjorie

1985-01-11

The Monsanto Company is planning to ask the Environmental Protection Agency for clearance to field test a genetically engineered microbial pesticide, bypassing the traditional approval process of the National Institutes of Health. Although only federally funded institutions are required to obtain NIH approval for genetic engineering tests, Monsanto is the first company to bypass the NIH regulatory process, which has become mired in a lawsuit brought by Jeremy Rifkin.

The Role of Bile After Roux-en-Y Gastric Bypass in Promoting Weight Loss and Improving Glycaemic Control

PubMed Central

Pournaras, Dimitri J.; Glicksman, Clare; Vincent, Royce P.; Kuganolipava, Shophia; Alaghband-Zadeh, Jamie; Mahon, David; Bekker, Jan H.R.; Ghatei, Mohammad A.; Bloom, Stephen R.; Walters, Julian R.F.; le Roux, Carel W.

2012-01-01

Gastric bypass leads to the remission of type 2 diabetes independently of weight loss. Our hypothesis is that changes in bile flow due to the altered anatomy may partly explain the metabolic outcomes of the operation. We prospectively studied 12 patients undergoing gastric bypass and six patients undergoing gastric banding over a 6-wk period. Plasma fibroblast growth factor (FGF)19, stimulated by bile acid absorption in the terminal ileum, and plasma bile acids were measured. In canine and rodent models, we investigated changes in the gut hormone response after altered bile flow. FGF19 and total plasma bile acids levels increased after gastric bypass compared with no change after gastric banding. In the canine model, both food and bile, on their own, stimulated satiety gut hormone responses. However, when combined, the response was doubled. In rats, drainage of endogenous bile into the terminal ileum was associated with an enhanced satiety gut hormone response, reduced food intake, and lower body weight. In conclusion, after gastric bypass, bile flow is altered, leading to increased plasma bile acids, FGF19, incretin. and satiety gut hormone concentrations. Elucidating the mechanism of action of gastric bypass surgery may lead to novel treatments for type 2 diabetes. PMID:22673227

Enhancing cell-free layer thickness by bypass channels in a wall.

PubMed

Saadatmand, M; Shimogonya, Y; Yamaguchi, T; Ishikawa, T

2016-07-26

When blood flows near a wall, red blood cells (RBCs) drift away from the wall and a cell-free layer (CFL) is formed adjacent to the wall. Controlling the CFL thickness is important for preventing adhesion of cells in the design of biomedical devices. In this study, a novel wall configuration with stenoses and bypass channels is proposed to increase the CFL thickness. We found that the presence of bypass channels modified the spatial distribution of cells and substantially increased the CFL downstream of the stenosis. A single-bypass geometry with 5% hematocrit (Hct) blood flow showed a 1.7μm increase in CFL thickness compared to without the bypass. In the case of three bypass channels, a 3μm increase in CFL thickness was observed. The CFL enhancement was observed up to 10% Hct, but no significant enhancement of CFL was indicated for 20% Hct blood flow. The mechanism of the CFL enhancement was investigated using a numerical simulation of the flow field. The results showed that the distance between each streamline and the corner of the stenosis compared with size of RBC was important parameter in regulating CFL thickness. These results show the potential of the proposed mechanism to prevent adhesion of cells to biomedical devices. Copyright © 2015 Elsevier Ltd. All rights reserved.

Does Previous Transradial Catheterization Preclude Use of the Radial Artery as a Conduit in Coronary Artery Bypass Surgery?

PubMed

Mounsey, Craig A; Mawhinney, Jamie A; Werner, Raphael S; Taggart, David P

2016-08-30

The radial artery (RA) is a commonly used conduit for coronary artery bypass grafting, and recent studies have demonstrated that it provides superior long-term patency rates to the saphenous vein in most situations. In addition, the RA is also being used with increasing frequency as the access point for coronary angiography and percutaneous coronary interventions. However, there has been concern for many years that these transradial procedures may have a detrimental impact on the function of RA grafts used in coronary artery bypass grafting, and there is now comprehensive evidence that such interventions cause morphologic and functional damage to the artery in situ. Despite this, there remain remarkably few studies investigating the use of previously cannulated RAs as grafts in coronary artery bypass surgery, and there are no clear guidelines on the use of the RA in coronary artery bypass grafting after its catheterization. This article will review concisely the evidence that transradial procedures cause damage to the RA, and discuss the impact this could have on previously cannulated RAs used as coronary artery bypass grafting conduits. On the basis of the evidence assessed, we make a number of recommendations to both surgeons and cardiologists regarding use of the RA in cardiovascular procedures. © 2016 American Heart Association, Inc.

Thermal activation of dislocations in large scale obstacle bypass

NASA Astrophysics Data System (ADS)

Sobie, Cameron; Capolungo, Laurent; McDowell, David L.; Martinez, Enrique

2017-08-01

Dislocation dynamics simulations have been used extensively to predict hardening caused by dislocation-obstacle interactions, including irradiation defect hardening in the athermal case. Incorporating the role of thermal energy on these interactions is possible with a framework provided by harmonic transition state theory (HTST) enabling direct access to thermally activated reaction rates using the Arrhenius equation, including rates of dislocation-obstacle bypass processes. Moving beyond unit dislocation-defect reactions to a representative environment containing a large number of defects requires coarse-graining the activation energy barriers of a population of obstacles into an effective energy barrier that accurately represents the large scale collective process. The work presented here investigates the relationship between unit dislocation-defect bypass processes and the distribution of activation energy barriers calculated for ensemble bypass processes. A significant difference between these cases is observed, which is attributed to the inherent cooperative nature of dislocation bypass processes. In addition to the dislocation-defect interaction, the morphology of the dislocation segments pinned to the defects play an important role on the activation energies for bypass. A phenomenological model for activation energy stress dependence is shown to describe well the effect of a distribution of activation energies, and a probabilistic activation energy model incorporating the stress distribution in a material is presented.

The effects of gastric bypass surgery on drug absorption and pharmacokinetics.

PubMed

Brocks, Dion R; Ben-Eltriki, Mohamed; Gabr, Raniah Q; Padwal, Raj S

2012-12-01

Being overweight is widespread in most societies and represents a major health threat. Gastric bypass surgery offers a highly effective mode of treatment for the morbidly obese patients. The procedures cause an alteration in normal gastrointestinal anatomy and physiology, with consequences not only on nutrient absorption, but also possibly on orally administered drugs. Bypass of the acidic environment of the stomach, partial impairment of bile salts-drug interactions and reduced absorptive surface, all create the potential for reduced absorption of drugs. This article provides an overview of the effects of obesity and the most prevalent type of gastric bypass (Roux-en-Y) on pharmacokinetics. Articles for review were searched using Pubmed. The absorption of those drugs with known bioavailability issues generally seem to be most affected by bypass surgery. It is important to consider the effect of obesity on pharmacokinetics independent of the bypass procedure, because it leads to a dramatic drop in body mass over a relatively short period of time. This may be associated with reversals in the influence of obesity on drug disposition to characteristics more in line with leaner patients. Drugs will differ in their pharmacokinetic response to surgery, limiting any general conclusions regarding the impact of the surgery on drug disposition.

Cost-utility analysis comparing laparoscopic vs open aortobifemoral bypass surgery.

PubMed

Krog, Anne Helene; Sahba, Mehdi; Pettersen, Erik M; Wisløff, Torbjørn; Sundhagen, Jon O; Kazmi, Syed Sh

2017-01-01

Laparoscopic aortobifemoral bypass has become an established treatment option for symptomatic aortoiliac obstructive disease at dedicated centers. Minimally invasive surgical techniques like laparoscopic surgery have often been shown to reduce expenses and increase patients' health-related quality of life. The main objective of our study was to measure quality-adjusted life years (QALYs) and costs after totally laparoscopic and open aortobifemoral bypass. This was a within trial analysis in a larger ongoing randomized controlled prospective multicenter trial, Norwegian Laparoscopic Aortic Surgery Trial. Fifty consecutive patients suffering from symptomatic aortoiliac occlusive disease suitable for aortobifemoral bypass surgery were randomized to either totally laparoscopic (n=25) or open surgical procedure (n=25). One patient dropped out of the study before surgery. We measured health-related quality of life using the EuroQol (EQ-5D-5L) questionnaire at 4 different time points, before surgery and for 6 months during follow-up. We calculated the QALYs gained by using the area under the curve for both groups. Costs were calculated based on prices for surgical equipment, vascular prosthesis and hospital stay. We found a significantly higher increase in QALYs after laparoscopic vs open aortobifemoral bypass surgery, with a difference of 0.07 QALYs, ( p =0.001) in favor of laparoscopic aortobifemoral bypass. The total cost of surgery, equipment and hospital stay after laparoscopic surgery (9,953 €) was less than open surgery (17,260 €), ( p =0.001). Laparoscopic aortobifemoral bypass seems to be cost-effective compared with open surgery, due to an increase in QALYs and lower procedure-related costs.

Cost-utility analysis comparing laparoscopic vs open aortobifemoral bypass surgery

PubMed Central

Krog, Anne Helene; Sahba, Mehdi; Pettersen, Erik M; Wisløff, Torbjørn; Sundhagen, Jon O; Kazmi, Syed SH

2017-01-01

Objectives Laparoscopic aortobifemoral bypass has become an established treatment option for symptomatic aortoiliac obstructive disease at dedicated centers. Minimally invasive surgical techniques like laparoscopic surgery have often been shown to reduce expenses and increase patients’ health-related quality of life. The main objective of our study was to measure quality-adjusted life years (QALYs) and costs after totally laparoscopic and open aortobifemoral bypass. Patients and methods This was a within trial analysis in a larger ongoing randomized controlled prospective multicenter trial, Norwegian Laparoscopic Aortic Surgery Trial. Fifty consecutive patients suffering from symptomatic aortoiliac occlusive disease suitable for aortobifemoral bypass surgery were randomized to either totally laparoscopic (n=25) or open surgical procedure (n=25). One patient dropped out of the study before surgery. We measured health-related quality of life using the EuroQol (EQ-5D-5L) questionnaire at 4 different time points, before surgery and for 6 months during follow-up. We calculated the QALYs gained by using the area under the curve for both groups. Costs were calculated based on prices for surgical equipment, vascular prosthesis and hospital stay. Results We found a significantly higher increase in QALYs after laparoscopic vs open aortobifemoral bypass surgery, with a difference of 0.07 QALYs, (p=0.001) in favor of laparoscopic aortobifemoral bypass. The total cost of surgery, equipment and hospital stay after laparoscopic surgery (9,953 €) was less than open surgery (17,260 €), (p=0.001). Conclusion Laparoscopic aortobifemoral bypass seems to be cost-effective compared with open surgery, due to an increase in QALYs and lower procedure-related costs. PMID:28670132

Quasi-steady Bingham plastic analysis of an electrorheological flow mode bypass damper with piston bleed

NASA Astrophysics Data System (ADS)

Lindler, Jason; Wereley, Norman M.

2003-06-01

We present an improved experimental validation of our nonlinear quasi-steady electrorheological (ER) and magnetorheological damper analysis, using an idealized Bingham plastic shear flow mechanism, for the flow mode of damper operation with leakage effect. To validate the model, a double-acting ER valve or bypass damper was designed and fabricated. Both the hydraulic cylinder and the bypass duct have cylindrical geometry, and damping forces are developed in the annular bypass via Poiseuille flow. The ER fluid damper contains a controlled amount of leakage around the piston head. The leakage allows ER fluid to flow from one side of the piston head to the opposite side without passing through the ER bypass. For this flow mode damper, the damping coefficient, defined as the ratio of equivalent viscous damping of the Bingham plastic material, Ceq, to the Newtonian viscous damping, C, is a function of the non-dimensional plug thickness only. The damper was tested for varying conditions of applied electric field and frequency using a mechanical damper dynamometer. In this analysis, the leakage damping coefficient with incorporated leakage effects, predict the amount of energy dissipated for a complete cycle of the piston rod. Measured force verses displacement cycles for multiple frequencies and electric fields validate the ability of the non-dimensional groups and the leakage damping coefficient to predict the damping levels for an ER bypass damper with leakage. Based on the experimental validation of the model using these data, the Bingham plastic analysis is shown to be an effective tool for the analysis-based design of double-acting ER bypass dampers.

Influence of norepinephrine and phenylephrine on frontal lobe oxygenation during cardiopulmonary bypass in patients with diabetes.

PubMed

Brassard, Patrice; Pelletier, Claudine; Martin, Mickaël; Gagné, Nathalie; Poirier, Paul; Ainslie, Philip N; Caouette, Manon; Bussières, Jean S

2014-06-01

Although utilization of vasopressors recently has been associated with reduced cerebral oxygenation, the influence of vasopressors on cerebral oxygenation during cardiopulmonary bypass in patients with diabetes is unknown. The aim of this study was to document the impact of norepinephrine and phenylephrine utilization on cerebral oxygenation in patients with and without diabetes during cardiopulmonary bypass. Prospective, clinical study. Academic medical center. Fourteen patients with diabetes and 17 patients without diabetes undergoing cardiac surgery. During cardiopulmonary bypass, norepinephrine (diabetics n = 6; non-diabetics n = 8) or phenylephrine (diabetics n = 8; non-diabetics n = 9) was administered intravenously to maintain mean arterial pressure above 60 mmHg. Mean arterial pressure, venous temperature, arterial oxygenation, and frontal lobe oxygenation (monitored by near-infrared spectroscopy) were recorded before anesthesia induction (baseline) and continuously during cardiopulmonary bypass. Frontal lobe oxygenation was lowered to a greater extent in diabetics versus non-diabetics with administration of norepinephrine (-14±13 v 3±12%; p<0.05). There was also a trend towards a greater reduction in cerebral oxygenation in diabetics versus non-diabetics with administration of phenylephrine (-12±8 v -6±7%; p = 0.1) during cardiopulmonary bypass. Administration of norepinephrine to restore mean arterial pressure during cardiopulmonary bypass is associated with a reduction in frontal lobe oxygenation in diabetics but not in patients without diabetes. Administration of phenylephrine also were associated with a trend towards a greater reduction in frontal lobe oxygenation in diabetics. The clinical implications of these findings deserve future consideration. © 2013 Elsevier Inc. All rights reserved.

Feasibility study on retinal vascular bypass surgery in isolated arterially perfused caprine eye model

PubMed Central

Chen, Y; Wu, W; Zhang, X; Fan, W; Shen, L

2011-01-01

Purpose To investigate the feasibility of bypassing occluded segments of retinal venous main vessels in isolated, arterially perfused caprine eyes via the closed-sky vitrectomy approach using keratoprosthesis. Methods Isolated caprine eyes were used in this study. For each eye, the retinal vessel was perfused by Krebs solution via ophthalmic artery, and pars plana vitrectomy was performed using temporary keratoprosthesis. All retinal micro-vascular maneuvers were performed in a closed-sky eyeball. The main retinal vein was blocked by endodiathermy at the site of the vessel's first branching. Two openings, several millimeters apart, were created by vascular punctures in both the main vein and its branch vein wall straddling the induced occluded segment. Catheterization was achieved using a flexible polyimide tube, with each end inserted into the vessel wall opening. A sealed connection between the vessel and the tube was obtained by endodiathermy. Bypass of the occluded retinal vein segment was thus achieved, and the patency of this vascular bypass was confirmed by intravascular staining. Results Puncturing, catheterization, and endodiathermy were viable by closed-sky approach using keratoprosthesis. Bypassing of the occluded retinal main vein segment was accomplished with the combination of these maneuvers. Good results were obtained in 23 of 38 (60%) caprine eyes. Conclusions This study demonstrated that bypassing the occluded segment of retinal main vein can be successfully performed in a closed-sky eyeball model of isolated, arterially perfused caprine eye. This early work indicated that the more advanced retinal vascular bypass surgery in in vivo eye may be feasible in the future. PMID:21921946

Biliary bypass surgery - Analysis of indications & outcome of different procedures.

PubMed

Hussain Talpur, K Altaf; Mahmood Malik, Arshad; Iqbal Memon, Amir; Naeem Qureshi, Jawed; Khan Sangrasi, Ahmed; Laghari, Abdul Aziz

2013-05-01

This study reports the indications and outcome of various biliary bypass surgical procedures from a single centre over a period of 10 years. This is a prospective observational study conducted over a period of 10 years (January 2001-december 2010). A total of 1500 patients were included, who underwent pancreatico-biliary surgery due to common bile duct (CBD) stones, congenital anomalies of biliary tree, unoperable pancreatico-biliary malignancies, CBD strictures and cases who developed iatrogenic biliary injuries during cholecystectomy (both open & laproscopic) during this period of time. The patients who required biliary bypass surgery were further analysed for indications and outcome. Out of 1500 patients 83(5.53%) required biliary bypass surgical procedures. The CBD stones were observed as the most common indication (25.3%), followed by CBD injuries after open(10.84%) or laproscopic-cholecystectomy (14.46%), carcinoma head of pancreas (12.05%) and CBD obstruction(14.46%) either due to CBD strictures or unknown distal obstruction. Roux-en-Y-hepatico-jejunostomy (26.51%) was the most frequently performed procedure, followed by choledochoduodenostomy and Roux-en-Y choledocho-jejunostomy (i.e. 25.3% and 12.05% respectively). Roux-en-Y biliary bypass procedure was observed to be associated with better outcome in terms of rate of complications as well duration of hospital stay. Biliary bypass surgical procedures are the better options to restore the continuity of biliary system in patients with iatrogenic biliary tree injuries and un-operable pancreatico-biliary malignancy. Roux-en-Y biliary bypass procedure is safe and problem solving method in these cases.

Biliary bypass surgery – Analysis of indications & outcome of different procedures

PubMed Central

Hussain Talpur, K.Altaf; Mahmood Malik, Arshad; Iqbal Memon, Amir; Naeem Qureshi, Jawed; Khan Sangrasi, Ahmed; Laghari, Abdul Aziz

2013-01-01

Objectives: This study reports the indications and outcome of various biliary bypass surgical procedures from a single centre over a period of 10 years. Methods: This is a prospective observational study conducted over a period of 10 years (January 2001-december 2010). A total of 1500 patients were included, who underwent pancreatico-biliary surgery due to common bile duct (CBD) stones, congenital anomalies of biliary tree, unoperable pancreatico-biliary malignancies, CBD strictures and cases who developed iatrogenic biliary injuries during cholecystectomy (both open & laproscopic) during this period of time. The patients who required biliary bypass surgery were further analysed for indications and outcome. Results: Out of 1500 patients 83(5.53%) required biliary bypass surgical procedures. The CBD stones were observed as the most common indication (25.3%), followed by CBD injuries after open(10.84%) or laproscopic-cholecystectomy (14.46%), carcinoma head of pancreas (12.05%) and CBD obstruction(14.46%) either due to CBD strictures or unknown distal obstruction. Roux-en-Y-hepatico-jejunostomy (26.51%) was the most frequently performed procedure, followed by choledochoduodenostomy and Roux-en-Y choledocho-jejunostomy (i.e. 25.3% and 12.05% respectively). Roux-en-Y biliary bypass procedure was observed to be associated with better outcome in terms of rate of complications as well duration of hospital stay. Conclusion: Biliary bypass surgical procedures are the better options to restore the continuity of biliary system in patients with iatrogenic biliary tree injuries and un-operable pancreatico-biliary malignancy. Roux-en-Y biliary bypass procedure is safe and problem solving method in these cases. PMID:24353631

Nutrient re-routing and altered gut-islet cell crosstalk may explain early relief of severe postprandial hypoglycaemia after reversal of Roux-en-Y gastric bypass.

PubMed

Svane, M S; Toft-Nielsen, M B; Kristiansen, V B; Hartmann, B; Holst, J J; Madsbad, S; Bojsen-Møller, K N

2017-12-01

Roux-en-Y gastric bypass is associated with an increased risk of postprandial hyperinsulinaemic hypoglycaemia, but the underlying pathophysiology remains poorly understood. We therefore examined the effect of re-routing of nutrient delivery on gut-islet cell crosstalk in a person with severe postprandial hypoglycaemia after Roux-en-Y gastric bypass. A person with severe postprandial hypoglycaemia, who underwent surgical reversal of Roux-en-Y gastric bypass, was studied before reversal and at 2 weeks and 3 months after reversal surgery using liquid mixed meal tests and hyperinsulinaemic-euglycaemic clamps. The nadir of postprandial plasma glucose rose from 2.8 mmol/l to 4.1 mmol/l at 2 weeks and to 4.4 mmol/l at 3 months after reversal. Concomitant insulin- and glucagon-like peptide-1 secretion (peak concentrations and area under the curve) clearly decreased after reversal, while concentrations of glucose-dependent insulinotropic polypeptide and ghrelin increased. Insulin clearance declined after reversal, whereas clamp-estimated peripheral insulin sensitivity was unchanged. The person remained without symptoms of hypoglycaemia, but had experienced significant weight gain at 15-month follow-up. Accelerated nutrient absorption may be a driving force behind postprandial hyperinsulinaemic hypoglycaemia after Roux-en-Y gastric bypass. Re-routing of nutrients by reversal of the Roux-en-Y gastric bypass diminished postprandial plasma glucose excursions, alleviated postprandial insulin and glucagon-like peptide-1 hypersecretion and eliminated postprandial hypoglycaemia, which emphasizes the importance of altered gut-islet cell crosstalk for glucose metabolism after Roux-en-Y gastric bypass. © 2017 Diabetes UK.

The anterior temporal artery: an underutilized but robust donor for revascularization of the distal middle cerebral artery.

PubMed

Tayebi Meybodi, Ali; Lawton, Michael T; Griswold, Dylan; Mokhtari, Pooneh; Payman, Andre; Benet, Arnau

2017-10-01

OBJECTIVE The anterior temporal artery (ATA) supplies an area of the brain that, if sacrificed, does not cause a noticeable loss of function. Therefore, the ATA may be used as a donor in intracranial-intracranial (IC-IC) bypass procedures. The capacities of the ATA as a donor have not been studied previously. In this study, the authors assessed the feasibility of using the ATA as a donor for revascularization of different segments of the distal middle cerebral artery (MCA). METHODS The ATA was studied in 15 cadaveric specimens (8 heads, excluding 1 side). First, the cisternal segment of the artery was untethered from arachnoid adhesions and small branches feeding the anterior temporal lobe and insular cortex, to evaluate its capacity for a side-to-side bypass to insular, opercular, and cortical segments of the MCA. Any branch entering the anterior perforated substance was preserved. Then, the ATA was cut at the opercular-cortical junction and the capacity for an end-to-side bypass was assessed. RESULTS From a total of 17 ATAs, 4 (23.5%) arose as an early MCA branch. The anterior insular zone and the frontal parasylvian cortical arteries were the best targets (in terms of mobility and caliber match) for a side-to-side bypass. Most of the insula was accessible for end-to-side bypass, but anterior zones of the insula were more accessible than posterior zones. End-to-side bypass was feasible for most recipient cortical arteries along the opercula, except for posterior temporal and parietal regions. Early ATAs reached significantly farther on the insular MCA recipients than non-early ATAs for both side-to-side and end-to-side bypasses. CONCLUSIONS The ATA is a robust arterial donor for IC-IC bypass procedures, including side-to-side and end-to-side techniques. The evidence provided in this work supports the use of the ATA as a donor for distal MCA revascularization in well-selected patients.

Cold-induced fluid extravasation during cardiopulmonary bypass in piglets can be counteracted by use of iso-oncotic prime.

PubMed

Farstad, Marit; Kvalheim, Venny Lise; Husby, Paul

2005-08-01

Hypothermic cardiopulmonary bypass is associated with increased fluid extravasation. This study aimed to compare whether iso-oncotic priming solutions, in contrast to crystalloids, could reduce the cold-induced fluid extravasation during cardiopulmonary bypass in piglets. Three groups were studied: the control group (CT group; n = 10), the albumin group (Alb group; n = 7), and the hydroxyethyl starch group (HES group; n = 7). Prime (1000 mL) and supplemental fluid were acetated Ringer solution, 4% albumin, and 6% hydroxyethyl starch, respectively. After 1 hour of normothermic cardiopulmonary bypass, hypothermic cardiopulmonary bypass (cooling to 28 degrees C within 15 minutes) was initiated and continued to 90 minutes. Fluid needs, plasma volume, changes in colloid osmotic pressure in plasma and interstitial fluid, hematocrit levels, and tissue water content were recorded, and protein masses and fluid extravasation rates were calculated. Colloid osmotic pressure in plasma decreased immediately after the start of cardiopulmonary bypass in the CT group but remained stable in the Alb and HES groups. Colloid osmotic pressure in interstitial fluid tended to decrease in the CT group and remained unchanged in the Alb group, whereas a slight increase was observed in the HES group. Immediately after the start of cooling, fluid extravasation rates increased from 0.15 +/- 0.10 to 0.64 +/- 0.12 mL . kg -1 . min -1 in the CT group, whereas no such increase was observed in the Alb and HES groups. The changes in fluid extravasation rates were reflected by corresponding changes in tissue water content. The use of albumin or hydroxyethyl starch as prime to preserve the colloid osmotic pressure during cardiopulmonary bypass causes a reduction in the cold-induced fluid extravasation compared with that seen with crystalloids. Albumin seems more effective than hydroxyethyl starch to limit cold-induced fluid shifts during cardiopulmonary bypass.

Effect of bypass fat supplementation on productive performance and blood biochemical profile in lactating Murrah (Bubalus bubalis) buffaloes.

PubMed

Ranjan, Amit; Sahoo, Biswanath; Singh, Vijay Kumar; Srivastava, Susant; Singh, Suresh Pratap; Pattanaik, Ashok Kumar

2012-10-01

The study investigated the effect of dietary supplementation of bypass fat on productive performance and blood biochemical profile of lactating Murrah buffaloes (Bubalus bubalis). Fifteen multiparous buffaloes (2-4 lactation) of early to mid lactation were divided in three homogenous groups T(1) (control), T(2), and T(3) of five each. The animals in T(1) were fed with a basal diet consisting of a concentrate mixture, green sorghum, and wheat straw as per requirements, while the animals in group T(2) and T(3) were fed with same ration supplemented with 0.7 % (100 g/day) and 1.4 % (200 g/day) bypass fat (on dry matter intake (DMI) basis), respectively. The feed intake, milk yield, and milk composition were not influenced by supplemental bypass fat. However, fat-corrected milk (6.5 %) yield was higher (P < 0.05) in T(3) (14.21) than that of T(1) (9.83) and similar with T(2) (11.05). Feed efficiency (milk yield/kg DMI) was higher (P < 0.05) in group T(3) (0.51) than that of T(1) (0.38) and T(2) (0.41) indicating that buffaloes fed with bypass fat which is 1.4 % (200 g/day) of the diet were economically more efficient. The serum cholesterol level was higher (P < 0.01) in bypass fat-supplemented group (T(2) and T(3)) of animals. Serum high density lipoprotein (HDL) cholesterol (good cholesterol) level was more (P < 0.05) than LDL cholesterol (bad cholesterol) level with higher dose of bypass fat in T(3) than T(2). It was concluded that bypass fat supplementation with 1.4 % of the diet (200 g/day) increased the fat-corrected milk production and feed efficiency along with serum HDL cholesterol level in lactating Murrah buffaloes.

Development of design and analysis methodology for composite bolted joints

NASA Astrophysics Data System (ADS)

Grant, Peter; Sawicki, Adam

1991-05-01

This paper summarizes work performed to develop composite joint design methodology for use on rotorcraft primary structure, determine joint characteristics which affect joint bearing and bypass strength, and develop analytical methods for predicting the effects of such characteristics in structural joints. Experimental results have shown that bearing-bypass interaction allowables cannot be defined using a single continuous function due to variance of failure modes for different bearing-bypass ratios. Hole wear effects can be significant at moderate stress levels and should be considered in the development of bearing allowables. A computer program has been developed and has successfully predicted bearing-bypass interaction effects for the (0/+/-45/90) family of laminates using filled hole and unnotched test data.

Smokers' rights to coronary artery bypass graft surgery.

PubMed

Heath, Janie; Braun, Mary Ann; Brindle, Margaret

2002-06-01

Imagine a health maintenance organization creating a policy to deny all smokers access to nonemergent coronary artery bypass graft surgery. The cost savings to the organization and society would be potentially significant. Now envision the smoker, a hardworking father with daily angina, and the provider, writing costly prescriptions to manage the angina. What ethical and legal questions do you suppose would present in that setting? Now imagine how you would respond if given this scenario of denying smokers access to nonemergent coronary artery bypass graft. This article discusses the implications of resource allocation with self-inflicted health behaviors such as smoking. Tough questions are raised that explore both the pros and the cons of smokers' rights to coronary artery bypass graft.

(Updated) NCI Fiscal 2016 Bypass Budget Proposes $25 Million for Frederick National Lab | Poster

Cancer.gov

By Nancy Parrish, Staff Writer; image by Richard Frederickson, Staff Photographer The additional funding requested for Frederick National Laboratory for Cancer Research (FNLCR) in the Fiscal 2016 Bypass Budget was $25 million, or approximately 3.5 percent of the total additional funding request of $715 million. Officially called the Professional Judgment Budget, the Bypass Budget is a result of the National Cancer Act of 1971, which authorizes NCI to submit a budget directly to the president, to send to Congress. With a focus on NCI’s research priorities and areas of cancer research with potential for investment, the Bypass Budget specifies additional funding, over and above the current budget, that is needed to advance

Comparative effectiveness of anticoagulation on midterm infrainguinal bypass graft patency.

PubMed

Liang, Nathan L; Baril, Donald T; Avgerinos, Efthymios D; Leers, Steven A; Makaroun, Michel S; Chaer, Rabih A

2017-08-01

Therapeutic anticoagulation (AC) is used clinically for prolongation of infrainguinal bypass patency, but evidence for the efficacy of this practice is conflicting. The objective of our study was to determine the association of AC with bypass graft primary patency. Clinical and comorbid data of patients undergoing infrainguinal bypass grafts to a below-knee target with at least 1 year of follow-up performed from 2003 to 2015 were obtained from the Society for Vascular Surgery Vascular Quality Initiative. Inverse propensity of treatment-weighted Cox regression was used to assess the effect of AC on patency in the total cohort while adjusting for clinical, operative, and comorbid differences between treatment groups. Subgroup analyses of distal targets and conduit type were performed. Perioperative complications were analyzed using propensity-weighted logistic regression. We identified 7612 bypass grafts with intact 1-year follow-up information from 2003 to 2015. The mean age was 67.5 ± 11.2 years; 30.5% (n = 2320) were female, and 28.6% (n = 2165) were discharged on therapeutic AC. The anticoagulated group had a higher rate of tibial, ankle, and pedal targets (52.1% [n = 1127] vs 47.6% [n = 2269]; P < .001), had a greater use of non-single-segment vein conduits (44.3% [n = 951] vs 26.5% [n = 1426]; P < .001), and was more likely to have had a previous ipsilateral bypass (27.2% [n = 589] vs 14.7% [n = 794]; P < .001) or stent (25.4% [n = 550] vs 20.9% [n = 1130]; P < .001). Estimated unadjusted primary patency was 70.8% ± 0.6% at 1 year and lower for anticoagulated bypasses (66.9% ± 1.2% vs 72.4% ± 0.7%; P < .001). Propensity-weighted analysis showed no significant association of AC with primary patency in the overall cohort (hazard ratio [HR], 0.98; 95% confidence interval [CI], 0.86-1.11; P = .8) but demonstrated a trend toward improvement of primary patency in those with a non-single-segment vein conduit to a below-knee popliteal target (HR, 0.85; 95% CI, 0.80-1.02; P = .09). AC was associated with significantly improved secondary patency in those with prosthetic bypass grafts (HR, 0.77; 95% CI, 0.62-0.96; P = .02) or prosthetic bypasses to an infrapopliteal target (HR, 0.72; 95% CI, 0.54-0.97; P = .02). Odds of postoperative wound complications were significantly higher in those receiving AC (odds ratio, 1.33; 95% CI, 1.11-1.61; P = .002). This study does not demonstrate a significant impact of therapeutic AC on primary patency for infrainguinal bypass grafts. Treatment with AC may benefit secondary patency in those with a prosthetic bypass, especially to an infrapopliteal target, but at an increased risk of postoperative wound complications. Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

The Role of Distance and Quality on Facility Selection for Maternal and Child Health Services in Urban Kenya.

PubMed

Escamilla, Veronica; Calhoun, Lisa; Winston, Jennifer; Speizer, Ilene S

2018-02-01

Universal access to health care requires service availability and accessibility for those most in need of maternal and child health services. Women often bypass facilities closest to home due to poor quality. Few studies have directly linked individuals to facilities where they sought maternal and child health services and examined the role of distance and quality on this facility choice. Using endline data from a longitudinal survey from a sample of women in five cities in Kenya, we examine the role of distance and quality on facility selection for women using delivery, facility-based contraceptives, and child health services. A survey of public and private facilities offering reproductive health services was also conducted. Distances were measured between household cluster location and both the nearest facility and facility where women sought care. A quality index score representing facility infrastructure, staff, and supply characteristics was assigned to each facility. We use descriptive statistics to compare distance and quality between the nearest available facility and visited facility among women who bypassed the nearest facility. Facility distance and quality comparisons were also stratified by poverty status. Logistic regression models were used to measure associations between the quality and distance to the nearest facility and bypassing for each outcome. The majority of women bypassed the nearest facility regardless of service sought. Women bypassing for delivery traveled the furthest and had the fewest facility options near their residential cluster. Poor women bypassing for delivery traveled 4.5 km further than non-poor women. Among women who bypassed, two thirds seeking delivery and approximately 46% seeking facility-based contraception or child health services bypassed to a public hospital. Both poor and non-poor women bypassed to higher quality facilities. Our findings suggest that women in five cities in Kenya prefer public hospitals and are willing to travel further to obtain services at public hospitals, possibly related to free service availability. Over time, it will be important to examine service quality and availability in public sector facilities with reduced or eliminated user fees, and whether it lends itself to a continuum of care where women can visit one facility for multiple services reducing travel burden.

New-generation stents compared with coronary bypass surgery for unprotected left main disease: A word of caution.

PubMed

Benedetto, Umberto; Taggart, David P; Sousa-Uva, Miguel; Biondi-Zoccai, Giuseppe; Di Franco, Antonino; Ohmes, Lucas B; Rahouma, Mohamed; Kamel, Mohamed; Caputo, Massimo; Girardi, Leonard N; Angelini, Gianni D; Gaudino, Mario

2018-05-01

With the advent of bare metal stents and drug-eluting stents, percutaneous coronary intervention has emerged as an alternative to coronary artery bypass grafting surgery for unprotected left main disease. However, whether the evolution of stents technology has translated into better results after percutaneous coronary intervention remains unclear. We aimed to compare coronary artery bypass grafting with stents of different generations for left main disease by performing a Bayesian network meta-analysis of available randomized controlled trials. All randomized controlled trials with at least 1 arm randomized to percutaneous coronary intervention with stents or coronary artery bypass grafting for left main disease were included. Bare metal stents and drug-eluting stents of first- and second-generation were compared with coronary artery bypass grafting. Poisson methods and Bayesian framework were used to compute the head-to-head incidence rate ratio and 95% credible intervals. Primary end points were the composite of death/myocardial infarction/stroke and repeat revascularization. Nine randomized controlled trials were included in the final analysis. Six trials compared percutaneous coronary intervention with coronary artery bypass grafting (n = 4654), and 3 trials compared different types of stents (n = 1360). Follow-up ranged from 6 months to 5 years. Second-generation drug-eluting stents (incidence rate ratio, 1.3; 95% credible interval, 1.1-1.6), but not bare metal stents (incidence rate ratio, 0.63; 95% credible interval, 0.27-1.4), and first-generation drug-eluting stents (incidence rate ratio, 0.85; 95% credible interval, 0.65-1.1) were associated with a significantly increased risk of death/myocardial infarction/stroke when compared with coronary artery bypass grafting. When compared with coronary artery bypass grafting, the highest risk of repeat revascularization was observed for bare metal stents (hazard ratio, 5.1; 95% confidence interval, 2.1-14), whereas first-generation drug-eluting stents (incidence rate ratio, 1.8; 95% confidence interval, 1.4-2.4) and second-generation drug-eluting stents (incidence rate ratio, 1.8; 95% confidence interval, 1.4-2.4) were comparable. The introduction of new-generation drug-eluting stents did not translate into better outcomes for percutaneous coronary intervention when compared with coronary artery bypass grafting. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Soluble tumor necrosis factor receptor p55 predicts cytokinemia and systemic inflammatory response after cardiopulmonary bypass.

PubMed

el-Barbary, Mahmoud; Khabar, Khalid S A

2002-08-01

To examine the behavior of soluble tumor necrosis factor (TNF) receptors in circulation before and after cardiopulmonary bypass and the relationship to the development of cytokinemia and acute complications comprising systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). The predictive value of soluble TNF receptor is assessed herein. Prospective study comparing prebypass and postbypass levels in patients with and without complications indicative of SIRS and MODS. Cardiac surgical intensive care unit in a tertiary care hospital. A total of 20 pediatric patients who underwent cardiopulmonary bypass during open heart surgery. Blood samples were collected from catheters before and 2 hrs and 24 hrs after the onset of bypass. We measured plasma levels of soluble TNF receptors by using enzyme-linked immunosorbent assay in 20 patients before and after cardiopulmonary bypass. Clinical data, including duration of bypass and tests or signs indicative of SIRS/MODS, were collected. Soluble TNF receptor I (p55 sR), significantly increased (2241 +/- 312 pg/mL) at 2 hrs after bypass (p <.0005) and remained elevated (2826 +/- 695 pg/mL) at 1 day after bypass (p <.005) when compared with prebypass levels (725 +/- 130 pg/mL). Patients with the acute complications of SIRS/MODS had a higher ratio of postbypass to prebypass p55 sR levels (5.0-fold, p <.001) when compared with patients with no SIRS/MODS (1.75-fold). Remarkably, before surgery, levels of TNF p55 sR predict both cytokinemia (r =.67 to.73, p <.05) and SIRS/MODS (p <.01). The prebypass levels of TNF p55 sR were consistently higher (range, 1000-1400 pg/mL) in patients who subsequently developed SIRS/MODS than the levels (range, 400-570 pg/mL) in patients who did not develop SIRS/MODS. Hypotension, respiratory dysfunctions, and coagulopathy were particularly more prevailing (p <.005) among the complications that were associated with high prebypass levels of TNF p55 sR. Soluble TNF receptor p55 can be employed as a predictive marker for cytokinemia and the development of SIRS/MODS that may arise from a major insult to the body such as cardiopulmonary bypass.

Heart bypass surgery - minimally invasive - discharge

MedlinePlus

... thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest . 2012;141(2 ... bypass surgery - minimally invasive Heart failure - overview High blood cholesterol ...

Surgical treatment of middle aortic syndrome with Takayasu arteritis or midaortic dysplastic syndrome.

PubMed

Kim, S M; Jung, I M; Han, A; Min, S-I; Lee, T; Ha, J; Kim, S J; Min, S-K

2015-08-01

Middle aortic syndrome (MAS) is a rare condition characterized by severe stenosis of the distal thoracic or abdominal aorta. The aims of this study are to define the anatomic characteristics of MAS and to review the various surgical methods and their outcomes in terms of long-term durability Ten adult patients were diagnosed with MAS caused by Takayasu arteritis (TA) or midaortic dysplastic syndrome and underwent surgical treatment between July 1992 and January 2013. The aortic lesions were mostly suprarenal (n = 7) and stenoses were commonly found in the celiac axis (n = 6), SMA (n = 7), and renal artery (n = 6). Indications for operation were uncontrolled hypertension in six patients and lower extremity claudication in four. Eight aortic bypasses, one supraceliac aortic interposition graft, and one bilateral aorto-renal bypass were performed. Adjunctive renal bypass with saphenous vein graft (n = 4) and IMA reimplantation (n = 2) were performed simultaneously. There was no post-operative mortality, and one complication of iliac dissection at the distal anastomosis site was detected and treated by stenting. Hypertension was cured or improved in five of the six patients, and lower extremity claudication improved in all of them. With a median follow up of 60 months (range, 12-263), all the aortic bypasses were patent and one adjunctive renal artery bypass graft with aortic bypass was occluded 29 months post-operatively. Aortic bypass for MAS is safe and shows excellent long-term durability. Considering the patients are relatively young with a long life expectancy, aggressive surgical treatment could be beneficial. Lifelong follow up to monitor complications and disease progression is necessary. Copyright © 2015 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

Surgical Treatment of Large or Giant Fusiform Middle Cerebral Artery Aneurysms: A Case Series.

PubMed

Xu, Feng; Xu, Bin; Huang, Lei; Xiong, Ji; Gu, Yuxiang; Lawton, Michael T

2018-04-14

Management of large or giant fusiform middle cerebral artery (MCA) aneurysms represents a significant challenge. To describe the authors' experience in the treatment of large or giant fusiform MCA aneurysm by using various surgical techniques. We retrospectively reviewed a database of aneurysms treated at our division between 2015 and 2017. Overall, 20 patients (11 males, 9 females) were identified, with a mean age of 40.7 years (range, 13-65 years; median, 43 years). Six patients (30%) had ruptured aneurysms and 14 (70%) had unruptured aneurysms. The mean aneurysm size was 19 mm (range, 10-35 mm). The aneurysms involved the prebifurcation in 5 cases, bifurcation in 4 cases, and postbifurcation in 11 cases. The aneurysms were treated by clip reconstruction (n = 5), clip wrapping (n = 1), proximal occlusion or trapping (n = 4), and bypass revascularization (n = 10). Bypasses included 7 low-flow superficial temporal artery-MCA bypasses, 2 high-flow extracranial-intracranial bypasses, and 1 intracranial-intracranial bypass (reanastomosis). Bypass patency was 90%. Nineteen aneurysms (95%) were completely obliterated, and no rehemorrhage occurred during follow-up. There was no procedural-related mortality. Clinical outcomes were good (modified Rankin Scale score ≤2) in 18 of 20 patients (90%) at the last follow-up. Surgical treatment strategy for large or giant fusiform MCA aneurysms should be determined on an individual basis, based on aneurysm morphology, location, size, and clinical status. Favorable outcomes can be achieved by various surgical techniques, including clip reconstruction, wrap clipping, aneurysm trapping, aneurysm excision followed by reanastomosis, and partial trapping with bypass revascularization. Copyright © 2018 Elsevier Inc. All rights reserved.

Treatment of aortic stenosis with aortic valve bypass (apicoaortic conduit) surgery: an assessment using computational modeling.

PubMed

Balaras, Elias; Cha, K S; Griffith, Bartley P; Gammie, James S

2009-03-01

Aortic valve bypass surgery treats aortic valve stenosis with a valve-containing conduit that connects the left ventricular apex to the descending thoracic aorta. After aortic valve bypass, blood is ejected from the left ventricle via both the native stenotic aortic valve and the conduit. We performed computational modeling to determine the effects of aortic valve bypass on aortic and cerebral blood flow, as well as the effect of conduit size on relative blood flow through the conduit and the native valve. The interaction of blood flow with the vascular boundary was modeled using a hybrid Eurelian-Lagrangian formulation, where an unstructured Galerkin finite element method was coupled with an immersed boundary approach. Our model predicted native (stenotic) valve to conduit flow ratios of 45:55, 52:48, and 60:40 for conduits with diameters of 20, 16, and 10 mm, respectively. Mean gradients across the native aortic valve were calculated to be 12.5, 13.8, and 17.6 mm Hg, respectively. Post-aortic valve bypass cerebral blood flow was unchanged from preoperative aortic valve stenosis configurations and was constant across all conduit sizes. In all cases modeled, cerebral blood flow was completely supplied by blood ejected across the native aortic valve. An aortic valve bypass conduit as small as 10 mm results in excellent relief of left ventricular outflow tract obstruction in critical aortic valve stenosis. The presence of an aortic valve bypass conduit has no effect on cerebral blood flow. All blood flow to the brain occurs via antegrade flow across the native stenotic valve; this configuration may decrease the long-term risk of cerebral thromboembolism.

Development of type 2 diabetes mellitus thirty-one years after Billroth II in a patient asking for diabetes surgery.

PubMed

Garciacaballero, M; Reyes-Ortiz, A; Toval, J A; Martínez-Moreno, J M; Miralles, F

2014-07-01

Diabetes surgery in obese and slim patients seems to be a superior alternative to the current medical treatment. Gastric bypass is an alternative treatment for diabetes. Nevertheless, there are still doubts whether diabetes can recur if you gain weight or if the effects are maintained over time. Other questions refer to the type of surgery to make the bypass limb length or reservoir size for the resolution of the Diabetes Mellitus. Male patient 69-year-old came to us in order to perform tailored One Anastomosis Gastric Bypass (BAGUA) to treat his type 2 diabetes mellitus and metabolic syndrome. He has a history of peptic ulcer treated with subtotal gastrectomy and Billroth II reconstruction 49 years ago. He currently is not obese and developed diabetes 31 years after surgery. Globally there are no reports of patients with normal BMI that after performing gastric bypass developed diabetes mellitus. There are cases where obese diabetic patients after gastric bypass improve or remits the T2DM, but it relapses due to insufficient weight loss or gain it. The patient with gastric bypass Billroth II type, should not developed diabetes. He is normal weight and not had weight gain that could be linked to the development of diabetes. The results generated by bariatric surgery are encouraging, but still do not clarify the precise way how surgery produces rapid improvement of systemic metabolism as in diabetes, but in our patient, the effect was quite different because the gastric bypass had no protective effect against diabetes. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Epidemiology of coronary artery bypass grafting at the Hospital Beneficência Portuguesa, São Paulo

PubMed Central

de Sousa, Alexandre Gonçalves; Fichino, Maria Zenaide Soares; da Silva, Gilmara Silveira; Bastos, Flávia Cortez Colosimo; Piotto, Raquel Ferrari

2015-01-01

Introduction The knowledge of the prevalence of risk factors and comorbidities, as well as the evolution and complications in patients undergoing coronary artery bypass graft allows comparison between institutions and evidence of changes in the profile of patients and postoperative evolution over time. Objective To profile (risk factors and comorbidities) and clinical outcome (complications) in patients undergoing coronary artery bypass graft in a national institution of great surgical volume. Methods A retrospective cohort study of patients undergoing coronary artery bypass graft in the hospital Beneficência Portuguesa de São Paulo, from July 2009 to July 2010. Results We included 3,010 patients, mean age of 62.2 years and 69.9% male. 83.8% of patients were hypertensive, 36.6% diabetic, 44.5% had dyslipidemia, 15.3% were smokers, 65.7% were overweight/obese, 29.3% had a family history of coronary heart disease. The expected mortality calculated by logistic EuroSCORE was 2.7%. The isolated CABG occurred in 89.3% and 11.9% surgery was performed without cardiopulmonary bypass. The most common complication was cardiac arrhythmia (18.7%), especially acute atrial fibrillation (14.3%). Pneumonia occurred in 6.2% of patients, acute renal failure in 4.4%, mediastinites in 2.1%, stroke in 1.8% and AMI in 1.2%. The in-hospital mortality was 5.4% and in isolated coronary artery bypass graft was 3.5%. The average hospital stay was 11 days with a median of eight days (3-244 days). Conclusion The profile of patients undergoing coronary artery bypass graft surgery in this study is similar to other published studies. PMID:25859865

Single center experience of aortic bypass graft for aortic arch obstruction in children.

PubMed

Shinkawa, Takeshi; Chipman, Carl; Holloway, Jessica; Tang, Xinyu; Gossett, Jeffrey M; Imamura, Michiaki

2017-01-01

The purpose of this study is to access the outcomes of aortic bypass graft placement in children. This is a retrospective review of all children having aortic bypass graft placement for aortic arch obstruction for the first time between 1982 and 2013 at a single institution. The actuarial survival and the freedom from aortic arch reoperation were calculated and compared between the groups. Seventy consecutive children underwent aortic bypass graft placements. The median age and body weight at the operation were 14 days and 3.6 kg. There were 7 early deaths, 6 late deaths, and 7 heart transplants during the median follow-up of 10.8 years (0.0-31.5 years). The actuarial transplant free survival was 64.7 % at 20 years and the freedom from aortic arch reoperation was 50.5 % at 10 years. Between the children younger than 1 year old and older than 1 year old, there were significant differences in actuarial transplant free survival (56.4 vs. 100 % at 15 years, p = 0.0042) and in the freedom from aortic arch reoperation (18.7 vs. 100 % at 10 years, p < 0.001). The children who received aortic bypass graft larger than 16 mm in size had no aortic arch reoperation at 15 years. The aortic bypass graft placement for aortic arch obstruction can be done with low mortality and morbidity for children who can receive bypass graft larger than 16 mm in size. However, it should be avoided for the neonates and infants except selected situations.

Kinetic Analysis of the Bypass of a Bulky DNA Lesion Catalyzed by Human Y-family DNA Polymerases

PubMed Central

Sherrer, Shanen M.; Sanman, Laura E.; Xia, Cynthia X.; Bolin, Eric R.; Malik, Chanchal K.; Efthimiopoulos, Georgia; Basu, Ashis K.; Suo, Zucai

2012-01-01

1-Nitropyrene (1-NP), a mutagen and potential carcinogen, is the most abundant nitro polyaromatic hydrocarbon in diesel exhaust, which reacts with DNA to form predominantly N-(deoxyguanosin-8-yl)-1-aminopyrene (dGAP). If not repaired, this DNA lesion is presumably bypassed in vivo by any of human Y-family DNA polymerases kappa (hPolκ), iota (hPolτ), eta (hPolη), and Rev1 (hRev1). Our running start assays demonstrated that each of these enzymes was indeed capable of traversing a site-specifically placed dGAP on a synthetic DNA template but hRev1 was stopped after lesion bypass. The time required to bypass 50% of the dGAP sites (t50bypass ) encountered by hPolη, hPolκ and hPolτ was determined to be 2.5 s, 4.1 s, and 106.5 s, respectively. The efficiency order of catalyzing translesion synthesis of dGAP (hPolη > hPolκ > hPolτ >> hRev1) is the same as the order for these human Y-family enzymes to elongate undamaged DNA. Although hPolη bypassed dGAP efficiently, replication by both hPolκ and hPolτ was strongly stalled at the lesion site and at a site immediately downstream from dGAP. By employing pre-steady state kinetic methods, a kinetic basis was established for polymerase pausing at these DNA template sites. Besides efficiency of bypass, the fidelity of those low-fidelity polymerases at these pause sites was also significantly decreased. Thus, if the translesion DNA synthesis of dGAP in vivo is catalyzed by a human Y-family DNA polymerase, e.g. hPolη, the process is certainly mutagenic. PMID:22324639

NATRIURETIC PEPTIDE SYSTEM GENE VARIANTS ARE ASSOCIATED WITH VENTRICULAR DYSFUNCTION AFTER CORONARY ARTERY BYPASS GRAFTING

PubMed Central

Fox, Amanda A.; Collard, Charles D.; Shernan, Stanton K.; Seidman, Christine E.; Seidman, Jonathan G.; Liu, Kuang-Yu; Muehlschlegel, Jochen D.; Perry, Tjorvi E.; Aranki, Sary F.; Lange, Christoph; Herman, Daniel S.; Meitinger, Thomas; Lichtner, Peter; Body, Simon C.

2009-01-01

Background Ventricular dysfunction (VnD) after primary coronary artery bypass grafting is associated with increased hospital stay and mortality. Natriuretic peptides have compensatory vasodilatory, natriuretic and paracrine influences on myocardial failure and ischemia. We hypothesized that natriuretic peptide system gene variants independently predict risk of VnD after primary coronary artery bypass grafting. Methods 1164 patients undergoing primary coronary artery bypass grafting with cardiopulmonary bypass at two institutions were prospectively enrolled. After prospectively defined exclusions, 697 Caucasian patients (76 with VnD) were analyzed. VnD was defined as need for ≥ 2 new inotropes and/or new mechanical ventricular support after coronary artery bypass grafting. 139 haplotype-tagging SNPs within 7 genes (NPPA; NPPB; NPPC; NPR1; NPR2; NPR3; CORIN) were genotyped. SNPs univariately associated with VnD were entered into logistic regression models adjusting for clinical covariates predictive of VnD. To control for multiple comparisons, permutation analyses were conducted for all SNP associations. Results After adjusting for clinical covariates and multiple comparisons within each gene, seven NPPA/NPPB SNPs (rs632793, rs6668352, rs549596, rs198388, rs198389, rs6676300, rs1009592) were associated with decreased risk of postoperative VnD (additive model; odds ratios 0.44–0.55; P = 0.010–0.036), and four NPR3 SNPs (rs700923, rs16890196, rs765199, rs700926) were associated with increased risk of postoperative VnD (recessive model; odds ratios 3.89–4.28; P = 0.007–0.034). Conclusions Genetic variation within the NPPA/NPPB and NPR3 genes is associated with risk of VnD after primary coronary artery bypass grafting. Knowledge of such genotypic predictors may result in better understanding of the molecular mechanisms underlying postoperative VnD. PMID:19326473

Modeling Sediment Bypassing around Rocky Headlands

NASA Astrophysics Data System (ADS)

George, D. A.; Largier, J. L.; Pasternack, G. B.; Erikson, L. H.; Storlazzi, C. D.; Barnard, P.

2016-12-01

Sediment bypassing rocky headlands remains understudied despite the importance of characterizing littoral processes and sediment budgets for erosion abatement, climate change adaptation, and beach management. This study was developed to identify controlling factors on and the mechanisms supporting sediment bypassing. Sediment flux around four idealized rocky headlands was investigated using the hydrodynamic model Delft3D and spectral wave model SWAN. The experimental design involved 120 simulations to explore the influence of headland morphology, substrate composition, sediment grain size, and oceanographic forcing. Headlands represented sizes and shapes found in natural settings, grain sizes ranged from fine to medium sand, and substrates from sandy beds to offshore bedrock reefs. The oceanography included a constructed representative tide, an alongshore background current, and four wave conditions derived from observational records in the eastern Pacific Ocean. A bypassing ratio was developed for alongshore flux between upstream and downstream cross-shore transects to determine the degree of blockage by a headland. Results showed that northwesterly oblique large waves (Hs = 7 m, Tp = 16 s) generated the most flux around headlands, whereas directly incident waves blocked flux across a headland apex. The headland shape heavily influenced the sediment fate by changing the relative angle between the shoreline and the incident waves. The bypassing ratio characterized each headland's capacity to allow alongshore flux under different wave conditions. All headlands may allow flux, although larger ones block sediment more effectively, promoting their ability to be littoral cell boundaries compared to smaller headlands. The controlling factors on sediment bypassing were determined to be wave angle, shape and size of the headland, and sediment grain size. This novel numerical modeling study advances headland modeling from the generic realm to broadly applicable classes of headlands and encourages further investigation into the mechanics of sediment bypassing.

Endoscopic intestinal bypass creation by using self-assembling magnets in a porcine model.

PubMed

Ryou, Marvin; Agoston, A Tony; Thompson, Christopher C

2016-04-01

A purely endoluminal method of GI bypass would be desirable for the treatment of obstruction, obesity, or metabolic syndrome. We have developed a technology based on miniature self-assembling magnets that create large-caliber anastomoses (Incisionless Anastomosis System [IAS]). The aim of this study was to evaluate procedural characteristics of IAS deployment and long-term anastomotic integrity and patency. We performed a 3-month survival study of Yorkshire pigs (5 interventions, 3 controls). Intervention pigs underwent simultaneous enteroscopy/colonoscopy performed with the animals under intravenous sedation. The IAS magnets were deployed and coupled with reciprocal magnets under fluoroscopy. Every 3 to 6 days pigs underwent endoscopy until jejunocolonic anastomosis (dual-path bypass) creation and magnet expulsion. Necropsies and histological evaluation were performed. The primary endpoints were technical success; secondary endpoints of anastomosis integrity, patency, and histological characteristics were weight trends. Under intravenous sedation, endoscopic bypass creation by using IAS magnets was successfully performed in 5 of 5 pigs (100%). Given porcine anatomy, the easiest dual-path bypass to create was between the proximal jejunum and colon. The mean procedure time was 14.7 minutes. Patent, leak-free anastomoses formed by day 4. All IAS magnets were expelled by day 12. All anastomoses were fully patent at 3 months with a mean diameter of 3.5 cm. The mean 3-month weight was 45 kg in bypass pigs and 78 kg in controls (P = .01). At necropsy, adhesions were absent. Histology showed full re-epithelialization across the anastomosis without fibrosis or inflammation. Large-caliber, leak-free, foreign body-free endoscopic intestinal bypass by using IAS magnets can be safely and rapidly performed in the porcine by model using only intravenous sedation. Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

High Frequency Single-Stage Multi-Bypass Pulse Tube Cryocooler for 23.8K

NASA Astrophysics Data System (ADS)

Yang, Junling; Hou, Xiaofeng; Yang, Luwei; Zhou, Yuan; Zhang, Liang

2008-03-01

A below 30K single-stage high-frequency multi-bypass pulse tube cryocooler(PTC) is introduced in this paper. At present, the lowest temperature of 27.46K has been achieved with input power of 100W and 23.8K with input power of 200W. Experiments show that if the area of multi-bypass and the length of inertance tube matching well, a better performance of PTC will be obtained.

Pleiotropic Alterations in Lipid Metabolism in Yeast sac1 Mutants: Relationship to “Bypass Sec14p” and Inositol Auxotrophy

PubMed Central

Rivas, Marcos P.; Kearns, Brian G.; Xie, Zhigang; Guo, Shuling; Sekar, M. Chandra; Hosaka, Kohei; Kagiwada, Satoshi; York, John D.; Bankaitis, Vytas A.

1999-01-01

SacIp dysfunction results in bypass of the requirement for phosphatidylinositol transfer protein (Sec14p) function in yeast Golgi processes. This effect is accompanied by alterations in inositol phospholipid metabolism and inositol auxotrophy. Elucidation of how sac1 mutants effect “bypass Sec14p” will provide insights into Sec14p function in vivo. We now report that, in addition to a dramatic accumulation of phosphatidylinositol-4-phosphate, sac1 mutants also exhibit a specific acceleration of phosphatidylcholine biosynthesis via the CDP-choline pathway. This phosphatidylcholine metabolic phenotype is sensitive to the two physiological challenges that abolish bypass Sec14p in sac1 strains; i.e. phospholipase D inactivation and expression of bacterial diacylglycerol (DAG) kinase. Moreover, we demonstrate that accumulation of phosphatidylinositol-4-phosphate in sac1 mutants is insufficient to effect bypass Sec14p. These data support a model in which phospholipase D activity contributes to generation of DAG that, in turn, effects bypass Sec14p. A significant fate for this DAG is consumption by the CDP-choline pathway. Finally, we determine that CDP-choline pathway activity contributes to the inositol auxotrophy of sac1 strains in a novel manner that does not involve obvious defects in transcriptional expression of the INO1 gene. PMID:10397762

Natural Product Screening Reveals Naphthoquinone Complex I Bypass Factors

PubMed Central

Mevers, Emily; Higgins, Kathleen W.; Fomina, Yevgenia; Zhang, Jianming; Mandinova, Anna; Newman, David; Shaw, Stanley Y.; Clardy, Jon; Mootha, Vamsi K.

2016-01-01

Deficiency of mitochondrial complex I is encountered in both rare and common diseases, but we have limited therapeutic options to treat this lesion to the oxidative phosphorylation system (OXPHOS). Idebenone and menadione are redox-active molecules capable of rescuing OXPHOS activity by engaging complex I-independent pathways of entry, often referred to as “complex I bypass.” In the present study, we created a cellular model of complex I deficiency by using CRISPR genome editing to knock out Ndufa9 in mouse myoblasts, and utilized this cell line to develop a high-throughput screening platform for novel complex I bypass factors. We screened a library of ~40,000 natural product extracts and performed bioassay-guided fractionation on a subset of the top scoring hits. We isolated four plant-derived 1,4-naphthoquinone complex I bypass factors with structural similarity to menadione: chimaphilin and 3-chloro-chimaphilin from Chimaphila umbellata and dehydro-α-lapachone and dehydroiso-α-lapachone from Stereospermum euphoroides. We also tested a small number of structurally related naphthoquinones from commercial sources and identified two additional compounds with complex I bypass activity: 2-methoxy-1,4-naphthoquinone and 2-methoxy-3-methyl-1,4,-naphthoquinone. The six novel complex I bypass factors reported here expand this class of molecules and will be useful as tool compounds for investigating complex I disease biology. PMID:27622560

Oil Bypass Filter Technology Evaluation, Fourth Quarterly Report, July--September 2003

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

James E. Francfort; Larry Zirker

2003-11-01

This fourth Oil Bypass Filter Technology Evaluation report details the ongoing fleet evaluation of an oil bypass filter technology by the Idaho National Engineering and Environmental Laboratory (INEEL) for the U.S. Department of Energy’s FreedomCAR & Vehicle Technologies Program. Eight four-cycle diesel-engine buses used to transport INEEL employees on various routes have been equipped with oil bypass filter systems from the puraDYN Corporation. The bypass filters are reported to have engine oil filtering capability of <1 micron and a built-in additive package to facilitate extended oil-drain intervals. To date, the eight buses have accumulated 259,398 test miles. This represents anmore » avoidance of 21 oil changes, which equates to 740 quarts (185 gallons) of oil not used or disposed of. To validate the extended oil-drain intervals, an oil-analysis regime evaluates the fitness of the oil for continued service by monitoring the presence of necessary additives, undesirable contaminants, and engine-wear metals. For bus 73450, higher values of iron have been reported, but the wear rate ratio (parts per million of iron per thousand miles driven) has remained consistent. In anticipation of also evaluating oil bypass systems on six Chevrolet Tahoe sport utility vehicles, the oil is being sampled on each of the Tahoes to develop a characterization history or baseline for each engine.« less

Apparatus and method for evaporator defrosting

DOEpatents

Mei, Viung C.; Chen, Fang C.; Domitrovic, Ronald E.

2001-01-01

An apparatus and method for warm-liquid defrosting of the evaporator of a refrigeration system. The apparatus includes a first refrigerant expansion device that selectively expands refrigerant for cooling the evaporator, a second refrigerant expansion device that selectively expands the refrigerant after the refrigerant has passed through the evaporator, and a defrosting control for the first refrigerant expansion device and second refrigerant expansion device to selectively defrost the evaporator by causing warm refrigerant to flow through the evaporator. The apparatus is alternately embodied with a first refrigerant bypass and/or a second refrigerant bypass for selectively directing refrigerant to respectively bypass the first refrigerant expansion device and the second refrigerant expansion device, and with the defrosting control connected to the first refrigerant bypass and/or the second refrigerant bypass to selectively activate and deactivate the bypasses depending upon the current cycle of the refrigeration system. The apparatus alternately includes an accumulator for accumulating liquid and/or gaseous refrigerant that is then pumped either to a refrigerant receiver or the first refrigerant expansion device for enhanced evaporator defrosting capability. The inventive method of defrosting an evaporator in a refrigeration system includes the steps of compressing refrigerant in a compressor and cooling the refrigerant in the condenser such that the refrigerant is substantially in liquid form, passing the refrigerant substantially in liquid form through the evaporator, and expanding the refrigerant with a refrigerant expansion device after the refrigerant substantially passes through the evaporator.

Tailored flow sequestration treatment using high-flow and low-flow bypass for partially thrombosed giant internal carotid artery aneurysm-a technical case report.

PubMed

Hasegawa, Hirotaka; Inoue, Tomohiro; Tamura, Akira; Saito, Isamu

2016-10-01

Direct clipping of giant partially thrombosed intracranial internal carotid artery (ICA) aneurysms is challenging, especially when important perforating arteries are involved. Proximal occlusion with bypass represents a possible alternative approach. An 80-year-old female presented with worsening visual acuity and severe headache caused by partially thrombosed giant (38 mm in diameter) aneurysms of the right ICA, suggestive of impending rupture. Direct clipping in conjunction with temporary occlusion of the lesion involving the anterior choroidal artery (AChA) was considered too risky. Thus, we sequestrated the ipsilateral ICA flow into a low-flow and a high-flow system using two external carotid artery (ECA)-ICA bypasses and one in situ bypass with cervical ICA ligation. As a result, the low-flow system by the superficial temporal artery-middle cerebral artery (MCA) bypass perfused mainly the proximal MCA lesions and aneurysm, whereas the high-flow system by ECA-radial artery-M2 bypass exclusively supplied the residual distal MCA area. This tailored flow sequestration successfully interrupted intra-aneurysmal flow and accelerated near-complete thrombosis of the aneurysm while preserving the AChA and avoiding any significant neurological deterioration. We conclude that this method is effective for the management of giant partially thrombosed aneurysms of the ICA, especially when direct clipping is difficult.

Resource utilization related to atrial fibrillation after coronary artery bypass grafting.

PubMed

Hravnak, Marilyn; Hoffman, Leslie A; Saul, Melissa I; Zullo, Thomas G; Whitman, Gayle R

2002-05-01

Studies of resource utilization by patients with new-onset atrialfibrillation after coronary artery bypass grafting have addressed only length of stay and bed charges. To compare resource utilization between patients with new-onset atrial fibrillation and patients without atrialfibrillation after isolated coronary artery bypass grafting. Retrospective review of clinical and administrative electronic databases for 720 subjects who underwent isolated coronary artery bypass grafting with cardiopulmonary bypass in 25 months at one medical center The prevalence of atrial fibrillation was determined, and resource utilization in various hospital cost centers was compared between subjects with and without atrialfibrillation. The prevalence of new-onset atrial fibrillation was 33.1%. Compared with subjects without atrialfibrillation, subjects with atrialfibrillation had a longer stay (5.8 +/- 2.4 vs. 4.4+/-1.2 days, P<.001), more days receiving mechanical ventilation (P =.002) and oxygen therapy (P<.001), and higher rates of readmission to the intensive care unit (4.6% vs. 0.2%, P<.001). Subjects with atrial fibrillation also had more laboratory tests (P<.001) and more days receiving cardiac drugs, heparin, diuretics, and electrolytes. Subjects with atrialfibrillation had higher total postoperative charges ($57261 +/- $17101 vs. $50905 +/- $10062, P = .001), a mean difference of $6356. The mean differences were greatest for bed charges ($1642), laboratory charges ($1215), pharmacy ($989), and respiratory care ($582). The economic impact of atrialfibrillation after coronary artery bypass grafting has been underestimated.

Hyperhomocysteinemia in bilateral anterior ischemic optic neuropathy after conventional coronary artery bypass graft: a case report.

PubMed

Niro, A; Sborgia, G; Sborgia, A; Alessio, G

2018-01-17

The incidence of anterior ischemic optic neuropathy after coronary artery bypass graft procedures ranges from 1.3 to 0.25%. The mechanisms of anterior ischemic optic neuropathy after cardiovascular procedures remain undefined but many systemic and related-to-surgery risk factors could underlie anterior ischemic optic neuropathy. In this case, we report a rare presentation of a bilateral anterior ischemic optic neuropathy after coronary artery bypass graft and speculate on the preoperative hyperhomocysteinemia as an independent risk factor for anterior ischemic optic neuropathy. A 56-year-old white man, a tobacco smoker with type 2 diabetes and coronary artery disease, underwent a conventional coronary artery bypass graft with extracorporeal circulation. In spite of ongoing anti-aggregation, antithrombotic, and vasodilator therapy, 10 days after the surgery he complained of severe bilateral visual loss. Funduscopy and fluorescein angiography revealed a bilateral anterior ischemic optic neuropathy. Analysis of preoperative laboratory tests revealed hyperhomocysteinemia. Hyperhomocysteinemia could increase the risk of ocular vascular damage and bilateral ocular involvement in patients who have undergone conventional coronary artery bypass graft.

Travel burden and dentist bypass among dentally insured children.

PubMed

McKernan, Susan C; Pooley, Mark J; Momany, Elizabeth T; Kuthy, Raymond A

2016-06-01

Using administrative data from Iowa Medicaid and a large private dental insurer, we compared distance to the nearest primary care dentist for children ages 6-15 in 2012. Additionally, we examined rates of provider bypass in both populations as an indicator of spatial accessibility to dental care. We calculated measures of travel burden, including distance to the nearest primary care dentist and distance to current primary care dentist. Distance outcomes and rates of bypass, traveling beyond the nearest dentist for care, were compared by insurance type. We found that Medicaid-enrolled children lived farther from the nearest dentist and farther from their current dentist than privately insured children. However, rates of bypass were higher among the privately insured population. These results were consistent among urban and rural residents; additionally, both rural populations demonstrated greater travel distances than urban dwellers. Travel burden was greater among Medicaid-enrolled children. Lower rates of bypass, in conjunction with lower rates of dental utilization in this population, may indicate a distance threshold beyond which dental care becomes unattainable. © 2016 American Association of Public Health Dentistry.

Treatment of Venous Aortorenal Bypass Graft Aneurysm Using a Stent-Graft

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

Novotny, Jiri, E-mail: jino@medicon.cz; Peregrin, Jan H.; Stribrna, Jarmila

2010-02-15

We present the case of a 77-year-old male patient who had undergone a bilateral venous aortorenal bypass graft 30 years previously. Thirteen years previously, the patient was shown to have a decrease in renal function, with mild shrinking of both kidneys; additionally, a stenosis was found in the left proximal anastomosis. At the most recent follow-up visit (1 year previously), ultrasound revealed an aneurysm (42 mm in diameter) of the left renal bypass graft; the finding was confirmed by CT angiography. A significant ostial stenosis of the left renal bypass graft was also confirmed. It was decided to place amore » self-expandable stent-graft into the aneurysm while also attempting to dilate the stenosis. Proximal endoleak after stent-graft placement necessitated the implantation of another, balloon-expandable stent-graft into the bypass graft ostium. Postprocedural angiography and follow-up by CT angiography at 3 months confirmed good patency of the stent-grafts and complete thrombosis of the aneurysmal sac, with preserved kidney perfusion. Renal function remained unaltered, while the hypertension is better controlled.« less

Extra-anatomic bypass for recurrent abdominal aortic and renal in-stent stenoses following radiotherapy for neuroblastoma.

PubMed

Luehr, Maximilian; Siepe, Matthias; Beyersdorf, Friedhelm; Schlensak, Christian

2009-04-01

We describe the case of an 11-year-old girl with an abdominal neuroblastoma which was operated and intraoperatively irradiated nine years ago. After six years, she developed stenoses of the infrarenal abdominal aorta and both renal arteries. Initial treatment of the stenosed vessels comprised endovascular balloon dilatations and repeated stent-graft implantations, including drug eluting stents. However, severe in-stent stenoses occurred during follow-up and the girl developed acute renal failure. Open surgery was performed with two extra-anatomic bypasses, a thoracic-to-abdominal aortic bypass and a left iliac-to-renal bypass, on an urgent basis. The postoperative course was uneventful and the patient was discharged home two weeks after the operation with full recovery of renal function. We conclude that endovascular stent-graft placement in children can only be a palliative treatment due to outgrowing of the stent-graft and the potential risk of re-stenosis, especially after a history of irradiation. Vascular surgery with placement of extra-anatomic bypasses will provide a definite treatment.

Triple bypass for advanced pancreatic head cancer associated with biliary stricture, duodenal stenosis, and recurrent obstructive pancreatitis.

PubMed

Kudo, Yuzan; Sato, Norihiro; Tamura, Toshihisa; Hirata, Keiji

2016-12-01

Bypass surgery for cancer of the pancreatic head is usually done to palliate the obstructive symptoms in the biliary and/or digestive system. However, it is uncommon for patients to require pancreatic duct drainage for recurrent obstructive pancreatitis. In this article, we report a surgical technique of triple bypass consisting of Roux-en-Y hepaticojejunostomy, gastrojejunostomy, and pancreaticojejunostomy for advanced pancreatic cancer. A 76-year-old male patient with locally advanced and metastatic pancreatic head cancer was referred to our department for biliary stricture, duodenal stenosis, and recurrent obstructive pancreatitis associated with persistent pancreatic pseudocyst. In an attempt to resolve all these problems simultaneously, a triple bypass was performed. The patient survived and continued to receive chemotherapy for almost 1 year after surgery without any serious complications. Thus, triple bypass is a useful surgical technique that could relief symptoms and offer better quality of life to patients with advanced pancreatic cancer presenting with biliary stricture, duodenal stenosis, and severe obstructive pancreatitis difficult to treat by medication or endoscopic procedures.

An engine trade study for a supersonic STOVL fighter-attack aircraft, volume 1

NASA Technical Reports Server (NTRS)

Beard, B. B.; Foley, W. H.

1982-01-01

The best main engine for an advanced STOVL aircraft flight demonstrator was studied. The STOVL aircraft uses ejectors powered by engine bypass flow together with vectored core exhaust to achieve vertical thrust capability. Bypass flow and core flow are exhausted through separate nozzles during wingborne flight. Six near term turbofan engines were examined for suitability for this aircraft concept. Fan pressure ratio, thrust split between bypass and core flow, and total thrust level were used to compare engines. One of the six candidate engines was selected for the flight demonstrator configuration. Propulsion related to this aircraft concept was studied. A preliminary candidate for the aircraft reaction control system for hover attitude control was selected. A mathematical model of transfer of bypass thrust from ejectors to aft directed nozzle during the transition to wingborne flight was developed. An equation to predict ejector secondary air flow rate and ram drag is derived. Additional topics discussed include: nozzle area control, ejector to engine inlet reingestion, bypass/core thrust split variation, and gyroscopic behavior during hover.

[Interventional catheter treatment of bypass graft stenosis: comparison of intracoronary stent implantation and balloon angioplasty].

PubMed

Heidland, U E; Heintzen, M P; Schoppmann, D; Michel, C J; Strauer, B E

2000-02-25

Balloon angioplasty of a stenosed bypass graft has a much higher risk of recurrent stenosis than dilatation of a stenosed native coronary artery. Intracoronary stent implantation has established itself as the better treatment of native coronary artery stenosis than conventional balloon angioplasty. However, there is still uncertainty whether intracoronary stent implantation in stenosed bypass vessels gives better long-term results than conventional balloon angioplasty. Results were retrospectively analyzed of unrandomized 224 primarily successful interventions--122 balloon dilatations and 102 stent implantations--performed between January 1996 and June 1998 on stenosed coronary bypass grafts, re-examined by coronary angiography an average of 6 months later. All but 11 patients were on combined aspirin and ticlopidine antiplatelet aggregation treatment. There was a significantly lower 6-month restenosis rate (30.4%) after stent implantation than after balloon dilatation (51.6%). The re-intervention rate was also significantly lower after stent implantation. These data suggest that stent implantation of stenosed coronary bypass grafts under cover of platelet-aggregation inhibition with aspirin and ticlopidine provides a lower restenosis and thus higher revascularization rate than conventional balloon dilatation.

Pure transumbilical SILS gastric bypass with mechanical circular gastrojejunal anastomosis feasibility.

PubMed

Pitot, Denis; Takieddine, Mazen; Abbassi, Ziad; Agrafiotis, Apostolos; Bruyns, Laurence; Ceuterick, Michel; Daoudi, Nabil; Dolimont, Amaury; Soulimani, Abdelak; Vaneukem, Pol

2014-10-01

Since Wittgrove introduced the laparoscopic version of the gastric bypass in 1994, the interest still remains in the decrease of the abdominal wall trauma in order to optimize the benefits of laparoscopy on postoperative pain, cosmesis, hospital stay, and convalescence in bariatric patients. This work is to report the feasibility of gastric bypass surgery by a pure transumbilical single-incision laparoscopic surgery (SILS) with a mechanical circular gastrojejunal anastomosis. Thirty-four patients (10 males and 24 females) were offered to receive gastric bypass with circular mechanical gastrojejunal anastomosis by Single Incision Laparoscopic Surgery (SILS) using pure transumbilical access. Anastomotic leak occurrence was the primary end-point. Patients demographics, operative time, additional trocarts, hemorrhage, intra abdominal abscess, length of post-operative stay, readmission, 30 days death, gastrojejunal anastomosis stricture, marginal ulcers, reflux complains, seromas, incisional hernias, and % excess BMI loss were also recorded in a prospective database. Primary end-point showed no anastomotic leak occurrence during the hospital stay or during the first 30 post-operative days. SILS gastric bypass with a circular mechanical gastrojejunal anastomosis is feasible and seems to be safe.

Ply-level failure analysis of a graphite/epoxy laminate under bearing-bypass loading

NASA Technical Reports Server (NTRS)

Naik, R. A.; Crews, J. H., Jr.

1988-01-01

A combined experimental and analytical study was conducted to investigate and predict the failure modes of a graphite/epoxy laminate subjected to combined bearing and bypass loading. Tests were conducted in a test machine that allowed the bearing-bypass load ratio to be controlled while a single-fastener coupon was loaded to failure in either tension or compression. Onset and ultimate failure modes and strengths were determined for each test case. The damage-onset modes were studied in detail by sectioning and micrographing the damaged specimens. A two-dimensional, finite-element analysis was conducted to determine lamina strains around the bolt hole. Damage onset consisted of matrix cracks, delamination, and fiber failures. Stiffness loss appeared to be caused by fiber failures rather than by matrix cracking and delamination. An unusual offset-compression mode was observed for compressive bearing-bypass laoding in which the specimen failed across its width along a line offset from the hole. The computed lamina strains in the fiber direction were used in a combined analytical and experimental approach to predict bearing-bypass diagrams for damage onset from a few simple tests.

Ply-level failure analysis of a graphite/epoxy laminate under bearing-bypass loading

NASA Technical Reports Server (NTRS)

Naik, R. A.; Crews, J. H., Jr.

1990-01-01

A combined experimental and analytical study was conducted to investigate and predict the failure modes of a graphite/epoxy laminate subjected to combined bearing and bypass loading. Tests were conducted in a test machine that allowed the bearing-bypass load ratio to be controlled while a single-fastener coupon was loaded to failure in either tension or compression. Onset and ultimate failure modes and strengths were determined for each test case. The damage-onset modes were studied in detail by sectioning and micrographing the damaged specimens. A two-dimensional, finite-element analysis was conducted to determine lamina strains around the bolt hole. Damage onset consisted of matrix cracks, delamination, and fiber failures. Stiffness loss appeared to be caused by fiber failures rather than by matrix cracking and delamination. An unusual offset-compression mode was observed for compressive bearing-bypass loading in which the specimen failed across its width along a line offset from the hole. The computed lamina strains in the fiber direction were used in a combined analytical and experimental approach to predict bearing-bypass diagrams for damage onset from a few simple tests.

Rankine cycle load limiting through use of a recuperator bypass

DOEpatents

Ernst, Timothy C.

2011-08-16

A system for converting heat from an engine into work includes a boiler coupled to a heat source for transferring heat to a working fluid, a turbine that transforms the heat into work, a condenser that transforms the working fluid into liquid, a recuperator with one flow path that routes working fluid from the turbine to the condenser, and another flow path that routes liquid working fluid from the condenser to the boiler, the recuperator being configured to transfer heat to the liquid working fluid, and a bypass valve in parallel with the second flow path. The bypass valve is movable between a closed position, permitting flow through the second flow path and an opened position, under high engine load conditions, bypassing the second flow path.

Dynamic response of a Mach 2.5 axisymmetric inlet and turbojet engine with a poppet-value controlled inlet stability bypass system when subjected to internal and external airflow transients

NASA Technical Reports Server (NTRS)

Sanders, B. W.

1980-01-01

The throat of a Mach 2.5 inlet that was attached to a turbojet engine was fitted with a poppet-valve-controlled stability bypass system that was designed to provide a large, stable airflow range. Propulsion system response and stability bypass performance were determined for several transient airflow disturbances, both internal and external. Internal airflow disturbances included reductions in overboard bypass airflow, power lever angle, and primary-nozzle area as well as compressor stall. For reference, data are also included for a conventional, fixed-exit bleed system. The poppet valves greatly increased inlet stability and had no adverse effects on propulsion system performance. Limited unstarted-inlet bleed performance data are presented.

Series Connected Converter for Control of Multi-Bus Spacecraft Power Utility

NASA Technical Reports Server (NTRS)

Beach, Raymond F. (Inventor); Brush, Andy (Inventor)

1997-01-01

The invention provides a power system using series connected regulators. Power from a source, such as a solar array, is processed through the regulators and provided to corresponding buses used to charge a battery and supply loads. The regulators employ a bypass loop around a DC-DC converter. The bypass loop connects a hot input of the converter to a return output, preferably though an inductor. Part of the current from the source passes through the bypass loop to the power bus. The converter bucks or boosts the voltage from the source to maintain the desired voltage at the bus. Thus, only part of the power is processed through the converter. The converter can also be used without the bypass loop to provide isolation. All of the converters can be substantially identical.

Five-year outcomes after laparoscopic gastric bypass and laparoscopic duodenal switch in patients with body mass index of 50 to 60: a randomized clinical trial.

PubMed

Risstad, Hilde; Søvik, Torgeir T; Engström, My; Aasheim, Erlend T; Fagerland, Morten W; Olsén, Monika Fagevik; Kristinsson, Jon A; le Roux, Carel W; Bøhmer, Thomas; Birkeland, Kåre I; Mala, Tom; Olbers, Torsten

2015-04-01

There is no consensus as to which bariatric procedure is preferred to reduce weight and improve health in patients with a body mass index higher than 50. To compare 5-year outcomes after Roux-en-Y gastric bypass (gastric bypass) and biliopancreatic diversion with duodenal switch (duodenal switch). Randomized clinical open-label trial at Oslo University Hospital, Oslo, Norway, and Sahlgrenska University Hospital, Gothenburg, Sweden. Participants were recruited between March 17, 2006, and August 20, 2007, and included 60 patients aged 20 to 50 years with a body mass index of 50 to 60. The current study provides the 5-year follow-up analyses by intent to treat, excluding one participant accepted for inclusion who declined being operated on prior to knowing to what group he was randomized. Laparoscopic gastric bypass and laparoscopic duodenal switch. Body mass index and secondary outcomes including anthropometric measures, cardiometabolic risk factors, pulmonary function, vitamin status, gastrointestinal symptoms, health-related quality of life, and adverse events. Sixty patients were randomly assigned and operated on with gastric bypass (n = 31) and duodenal switch (n = 29). Fifty-five patients (92%) completed the study. Five years after surgery, the mean reductions in body mass index were 13.6 (95% CI, 11.0-16.1) and 22.1 (95% CI, 19.5-24.7) after gastric bypass and duodenal switch, respectively. The mean between-group difference was 8.5 (95% CI, 4.9-12.2; P < .001). Remission rates of type 2 diabetes mellitus and metabolic syndrome and changes in blood pressure and lung function were similar between groups. Reductions in total cholesterol, low-density lipoprotein cholesterol, triglycerides, and fasting glucose were significantly greater after duodenal switch compared with gastric bypass. Serum concentrations of vitamin A and 25-hydroxyvitamin D were significantly reduced after duodenal switch compared with gastric bypass. Duodenal switch was associated with more gastrointestinal adverse effects. Health-related quality of life was similar between groups. Patients with duodenal switch underwent more surgical procedures related to the initial procedure (13 [44.8%] vs 3 [9.7%] patients; P = .002) and had significantly more hospital admissions compared with patients with gastric bypass. In patients with a body mass index of 50 to 60, duodenal switch resulted in greater weight loss and greater improvements in low-density lipoprotein cholesterol, triglyceride, and glucose levels 5 years after surgery compared with gastric bypass while improvements in health-related quality of life were similar. However, duodenal switch was associated with more surgical, nutritional, and gastrointestinal adverse effects. clinicaltrials.gov Identifier: NCT00327912.

Turbine Engine with Differential Gear Driven Fan and Compressor

NASA Technical Reports Server (NTRS)

Suciu, Gabriel L. (Inventor); Pagluica, Gino J. (Inventor); Duong, Loc Quang (Inventor); Portlock, Lawrence E. (Inventor)

2013-01-01

A gas turbine engine provides a differential gear system coupling the turbine to the bypass fan and the compressor. In this manner, the power/speed split between the bypass fan and the compressor can be optimized under all conditions. In the example shown, the turbine drives a sun gear, which drives a planet carrier and a ring gear in a differential manner. One of the planet carrier and the ring gear is coupled to the bypass fan, while the other is coupled to the compressor.

A Bovine Hemoglobin-Based Oxygen Carrier as Pump Prime for Cardiopulmonary Bypass: Reduced Systemic Lactic Acidosis and Improved Cerebral Oxygen Metabolism During Low-flow in a Porcine Model

DTIC Science & Technology

2010-11-10

1 A bovine hemoglobin-based oxygen carrier as pump prime for cardiopulmonary bypass: reduced systemic lactic acidosis and improved cerebral...2010 2. REPORT TYPE Final Report 3. DATES COVERED (From - To) June 2007 - November 2010 4. TITLE AND SUBTITLE A bovine hemoglobin-based oxygen...carrier as pump prime for cardiopulmonary bypass: reduced systemic lactic acidosis and improved cerebral oxygen metabolism during low-flow in a

Mammary artery harvesting using the Da Vinci Si robotic system

PubMed Central

Canale, Leonardo Secchin; Bonatti, Johannes

2014-01-01

Internal mammary artery harvesting is an essential part of any coronary artery bypass operation. Totally endoscopic coronary artery bypass graft surgery has become reality in many centers as a safe and effective alternative to conventional surgery in selected patients. Internal mammary artery harvesting is the initial part of the procedure and should be performed equally safely if one wants to achieve excellence in patency rates for the bypass. We here describe the technique for mammary harvesting with the Da Vinci Si robotic system. PMID:24896171

Treatment of hand ischemia following angioaccess surgery using the distal revascularization interval-ligation technique with preservation of vascular access: description of an 18-case series.

PubMed

Sessa, Carmine; Riehl, Gregory; Porcu, Paolo; Pichot, Olivier; Palacin, Pedro; Maghlaoua, Mohamed; Magne, Jean-Luc

2004-11-01

Hand ischemia is a rare complication of angioaccess surgery for hemodialysis. Management usually requires ligation of the arteriovenous fistula (AVF). The purpose of this report is to describe our experience with the use of the distal revascularization interval-ligation (DRIL) technique for treatment of ischemia without ligation of the AVF. From January 1999 to September 2002, the DRIL technique was used to treat 18 patients (10 men, 8 women, 10 diabetic patients) with severe paresthesia of the hand (n = 9) and finger necrosis (n = 10). The AVF was located at the elbow in 16 patients and at the wrist in 2 patients. Mean flow distal to the AVF was less than 10 mL in 5 patients, less than 5 mL in 10, and unmeasurable in 3. The conduit used for all DRIL arterial bypasses, including 15 brachiobrachial bypasses, 1 axillobrachial bypass, 1 brachioradial bypass, and 1 radioradial bypass, was the great saphenous vein graft. Trophic manifestations required finger amputation in five patients, pulpar necrosis resection in four, and transmetacarpal amputation of the index finger in one patient. Symptoms disappeared in 13 patients (73%) and improved in 5 (27%). The time required for healing of finger amputations and trophic manifestations ranged from 15 days to 2 months. Mean arterial flow through the DRIL bypass was 50 mL/min (range, 20-90 mL/min). With a mean follow-up interval of 16 months (range, 5-48 months), primary patency of the DRIL artery bypass and AVF was 94% and the limb salvage rate was 100%. The DRIL technique is the most effective procedure for treatment of angioaccess-induced hand ischemia. This technique can be used to achieve persistent relief of symptoms with continued access patency. The DRIL artery bypass improves vacularization of the hand, and ligature of the artery stops the vascular steal without affecting hemodialysis access. The DRIL technique should be proposed as first-line treatment for hand ischemia due to AVF for hemodialysis.

Coronary Artery Bypass

MedlinePlus

... 000 procedures performed each year in the United States. Arteries can become clogged over time by the buildup of fatty plaque. Bypass surgery improves the blood flow to the heart with a new route or “ ...

VIEW OF ONEONTA TUNNEL, CURRENT BYPASS ROAD IS ON THE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF ONEONTA TUNNEL, CURRENT BYPASS ROAD IS ON THE LEFT - Historic Columbia River Highway, Oneonta Tunnel, Adjacent to Historic Columbia River Highway through Oneonta Point, Troutdale, Multnomah County, OR

[Psychoprophylaxis in patients after coronary artery bypass graft operations].

PubMed

Rymaszewska, Joanna; Chładzińska-Kiejna, Sylwia; Górna, Renata; Kustrzycki, Wojciech

2004-05-01

The paper presented problems of quality of life and psychosocial functioning of patients following coronary artery bypass grafting operations. Possibilities of psychoprophylactic effects towards these patients and its efficacy were described.

Supersonic through-flow fan engine and aircraft mission performance

NASA Technical Reports Server (NTRS)

Franciscus, Leo C.; Maldonado, Jaime J.

1989-01-01

A study was made to evaluate potential improvement to a commercial supersonic transport by powering it with supersonic through-flow fan turbofan engines. A Mach 3.2 mission was considered. The three supersonic fan engines considered were designed to operate at bypass ratios of 0.25, 0.5, and 0.75 at supersonic cruise. For comparison a turbine bypass turbojet was included in the study. The engines were evaluated on the basis of aircraft takeoff gross weight with a payload of 250 passengers for a fixed range of 5000 N.MI. The installed specific fuel consumption of the supersonic fan engines was 7 to 8 percent lower than that of the turbine bypass engine. The aircraft powered by the supersonic fan engines had takeoff gross weights 9 to 13 percent lower than aircraft powered by turbine bypass engines.

The effect of laparoscopic Roux-en-Y gastric bypass on fibromyalgia.

PubMed

Saber, Alan A; Boros, Michael J; Mancl, Tara; Elgamal, Mohamed H; Song, Susrap; Wisadrattanapong, Therawat

2008-06-01

Fibromyalgia is a chronic debilitating disorder affecting 3-5% of the US population. Treatment of this disorder is a challenge. The incidental finding of improvement of fibromyalgia following laparoscopic Roux-en-Y gastric bypass stimulated us to study this phenomenon. A retrospective chart review of patients with fibromyalgia who underwent laparoscopic Roux-en-Y gastric bypass. Postoperative decrease in median of BMI from 49.4 to 29.7 was significant (p value = 0.0010). This was associated with statistically significant improvement in median of pain score (p value = 0.0010) and median points of tenderness (p value = 0.0010). Significant weight loss following laparoscopic Roux-en-Y gastric bypass is associated with resolution or improvement of fibromyalgia. Consequently, the bariatric surgeon should be a member of the multidisciplinary team approach for treating fibromyalgia.

Axillofemoral Bypass Markedly Improved Acute Decompensated Heart Failure and Kidney Injury in a Patient with Severely Calcified Stenosis of Thoracoabdominal Aorta (Atypical Aortic Coarctation).

PubMed

Ishizuka, Masato; Yamada, Shintaro; Maemura, Sonoko; Yamamoto, Keisuke; Takizawa, Masataka; Uozumi, Hiroki; Minegishi, Sachito; Kobayashi, Jotaro; Ikenouchi, Hiroshi

2017-10-21

Atypical aortic coarctation (AAC) has been reported to occur anywhere along the aorta, except for the ascending aorta. The associated symptoms include hypotension in the lower half of the body, secondary hypertension in the upper half of the body, and heart failure. Here we present an 80-year-old Asian woman complaining of progressive exertional dyspnea. She was diagnosed with acute decompensated heart failure and kidney injury due to severely calcified stenosis of the thoracoabdominal aorta, the so called AAC. She received hemodiafiltration, and pulmonary congestion improved in part. Generally, surgical treatments are quite invasive in elderly patients. Endovascular stent graft placement is less invasive, however, fracture and rupture should be considered at severely calcified lesions like this case. Therefore, we selected extra-anatomical axillofemoral bypass. Her recovery after the surgery was remarkable. In a few days, she became free from hemodiafiltration, intravenous diuretics, and oxygen administration. We thought the contributive factors are the increase in kidney blood flow and the correction of afterload mismatch. The decrease in pulse pressure may reflect the reduction in systemic arterial compliance by axillofemoral bypass. The operative mortality of axillofemoral bypass was reported to be acceptable, although the patency of the axillofemoral bypass graft was not high enough. In conclusion, axillofemoral bypass is effective and feasible for elderly patients with acute decompensated heart failure and kidney injury due to AAC.

Oil Bypass Filter Technology Evaluation - Third Quarterly Report, April--June 2003

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

Laurence R. Zirker; James E. Francfort

2003-08-01

This Third Quarterly report details the ongoing fleet evaluation of an oil bypass filter technology by the Idaho National Engineering and Environmental Laboratory (INEEL) for the U.S. Department of Energy’s FreedomCAR & Vehicle Technologies Program. Eight full-size, four-cycle diesel-engine buses used to transport INEEL employees on various routes have been equipped with oil bypass filter systems from the PuraDYN Corporation. The reported engine lubricating oil-filtering capability (down to 0.1 microns) and additive package of the bypass filter system is intended to extend oil-drain intervals. To validate the extended oil-drain intervals, an oil-analysis regime monitors the presence of necessary additives inmore » the oil, detects undesirable contaminants and engine wear metals, and evaluates the fitness of the oil for continued service. The eight buses have accumulated 185,000 miles to date without any oil changes. The preliminary economic analysis suggests that the per bus payback point for the oil bypass filter technology should be between 108,000 miles when 74 gallons of oil use is avoided and 168,000 miles when 118 gallons of oil use is avoided. As discussed in the report, the variation in the payback point is dependant on the assumed cost of oil. In anticipation of also evaluating oil bypass systems on six Chevrolet Tahoe sport utility vehicles, the oil is being sampled on the six Tahoes to develop an oil characterization history for each engine.« less

Maximal blood flow acceleration analysis in the early diastolic phase for aortocoronary artery bypass grafts: a new transit-time flow measurement predictor of graft failure following coronary artery bypass grafting.

PubMed

Handa, Takemi; Orihashi, Kazumasa; Nishimori, Hideaki; Yamamoto, Masaki

2016-11-01

Maximal graft flow acceleration (max df/dt) determined using transit-time flowmetry (TTFM) in the diastolic phase was assessed as a potential predictor of graft failure for aortocoronary artery (AC) bypass grafts in coronary artery bypass patients. Max df/dt was retrospectively measured in 114 aortocoronary artery bypass grafts. TTFM data were fitted to a 9-polynomial curve, which was derived from the first-derivative curve, to measure max df/dt (9-polynomial max df/dt). Abnormal TTFM was defined as a mean flow of <15 ml/min, a pulsatility index of >5 or a diastolic filling ratio of <50 %. Postoperative assessments were routinely performed by coronary artery angiography (CAG) at 1 year after surgery. Using TTFM, 68 grafts were normal, 4 of which were failing on CAG, and 46 grafts were abnormal, 21 of which were failing on CAG. 9-polynomial max df/dt was significantly lower in abnormal TTFM/failing by the CAG group compared with abnormal TTFM/patent by the CAG group (1.08 ± 0.89 vs. 2.05 ± 1.51 ml/s(2), respectively; P < 0.01, Mann-Whitney U test, Holm adjustment). TTFM 9-polynomial max df/dt in the early diastolic phase may be a promising predictor of future graft failure for AC bypass grafts, particularly in abnormal TTFM grafts.

Laparoscopic Band-Separated One Anastomosis Gastric Bypass.

PubMed

Ospanov, Oral B

2016-09-01

This video demonstrates laparoscopic band-separated one anastomosis gastric bypass-combining the advantages of banding and gastric bypass without stapler and cutter use. This is basically a gastrojejunal loop bypass above an obstructive band in the upper stomach. An adjustable low pressure "Medsil" gastric band was introduced in the abdomen and retracted through the retrogastric tunnel. The front wall of the stomach below the band was displaced in the upward direction through the ring band, increasing the size of the anterior portion of the stomach pouch so that a gastroenteroanastomosis could be created at this point. Gastro-gastric sutures were placed to create a gastro-gastric plication around the band and hold it in position. The band tubing was exteriorized and connected to a special port, which was secured to the abdominal wall fascia. A jejunal loop was created about 200 cm from the ligament of Treitz and anastomosed to the gastric pouch by hand using Vicryl 2/0 sutures. Between November 2015 and February 2016, the study was performed on 10 patients. The average operating time for all cases was 75 min (range 63-87). There was no morbidity or mortality. No complications were observed, including band erosion and band infection. Operation costs were about $2000 lower with this method than with standard gastric bypass surgery. Postop the patients lost weight by 3-4 kg per month. Preliminary results show that laparoscopic band-separated one anastomosis gastric bypass have feasibility, safety, efficacy, and reduced operating costs.

The effects of bariatric surgical procedures on the improvement of metabolic syndrome in morbidly obese patients: Comparison of laparoscopic sleeve gastrectomy versus laparoscopic Roux-en-Y gastric bypass.

PubMed

Kafalı, Mehmet Ertuğrul; Şahin, Mustafa; Ece, İlhan; Acar, Fahrettin; Yılmaz, Hüseyin; Alptekin, Hüsnü; Ateş, Leyla

2017-01-01

The objective of this study was to evaluate patients who underwent laparoscopic Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy in terms of weight loss, metabolic parameters, and postoperative complications. Data on patients who underwent laparoscopic Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy with a diagnosis of morbid obesity between January 2012 and June 2014 were retrospectively evaluated. Patients were compared in terms of age, sex, body mass index, duration of operation, American Society of Anesthesiologists score, perioperative complications, length of hospital stay, and long term follow-up results. During the study period, 91 patients (45 laparoscopic Roux-en-Y gastric bypass and 46 laparoscopic sleeve gastrectomy) underwent bariatric surgery. There was no difference between the two groups in terms of preoperative patient characteristics. Both groups showed statistically significant weight loss and improvement in co-morbidities when compared with the preoperative period. Weight loss and improvement in metabolic parameters were similar in both groups. The duration of operation and hospital stay was longer in the laparoscopic Roux-en-Y gastric bypass group. Furthermore, the rate of total complications was significantly lower in the laparoscopic sleeve gastrectomy group. Laparoscopic sleeve gastrectomy is a safe and effective method with a significantly lower complication rate and length of hospital stay than laparoscopic Roux-en-Y gastric bypass, with similar improvement rates in metabolic syndrome.

Pilot validation of an individualised pharmacokinetic algorithm for protamine dosing after systemic heparinisation for cardiopulmonary bypass.

PubMed

Miles, Lachlan F; Marchiori, Paolo; Falter, Florian

2017-09-01

This manuscript represents a pilot study assessing the feasibility of a single-compartment, individualised, pharmacokinetic algorithm for protamine dosing after cardiopulmonary bypass. A pilot cohort study in a specialist NHS cardiothoracic hospital targeting patients undergoing elective cardiac surgery using cardiopulmonary bypass. Patients received protamine doses according to a pharmacokinetic algorithm (n = 30) or using an empirical, fixed-dose model (n = 30). Categorical differences between the groups were evaluated using the Chi-squared test or Fisher's exact test. Continuous data was analysed using a paired Student's t-test for parametric data and the paired samples Wilcoxon test for non-parametric data. Patients who had protamine dosing according to the algorithm demonstrated a lower protamine requirement post-bypass relative to empirical management as measured by absolute dose (243 ± 49mg vs. 305 ± 34.7mg; p<0.001) and the heparin to protamine ratio (0.79 ± 0.12 vs. 1.1 ± 0.15; p<0.001). There was no difference in the pre- to post-bypass activated clotting time (ACT) ratio (1.05 ± 0.12 vs. 1.02 ± 0.15; p=0.9). Patients who received protamine according to the algorithm had no significant difference in transfusion requirement (13.3% vs. 30.0%; p=0.21). This study showed that an individualized pharmacokinetic algorithm for the reversal of heparin after cardiopulmonary bypass is feasible in comparison with a fixed dosing strategy and may reduce the protamine requirement following on-pump cardiac surgery.

Resource Utilization Related to Atrial Fibrillation After Coronary Artery Bypass Grafting

PubMed Central

Hravnak, Marilyn; Hoffman, Leslie A.; Saul, Melissa I.; Zullo, Thomas G.; Whitman, Gayle R.

2013-01-01

Background Studies of resource utilization by patients with new-onset atrial fibrillation after coronary artery bypass grafting have addressed only length of stay and bed charges. Objective To compare resource utilization between patients with new-onset atrial fibrillation and patients without atrial fibrillation after isolated coronary artery bypass grafting. Methods Retrospective review of clinical and administrative electronic databases for 720 subjects who underwent isolated coronary artery bypass grafting with cardiopulmonary bypass in 25 months at one medical center. The prevalence of atrial fibrillation was determined, and resource utilization in various hospital cost centers was compared between subjects with and without atrial fibrillation. Results The prevalence of new-onset atrial fibrillation was 33.1%. Compared with subjects without atrial fibrillation, subjects with atrial fibrillation had a longer stay (5.8 ± 2.4 vs 4.4 ± 1.2 days, P< .001), more days receiving mechanical ventilation (P=.002) and oxygen therapy (P< .001), and higher rates of readmission to the intensive care unit (4.6% vs 0.2%, P< .001). Subjects with atrial fibrillation also had more laboratory tests (P< .001) and more days receiving cardiac drugs, heparin, diuretics, and electrolytes. Subjects with atrial fibrillation had higher total postoperative charges ($57261 ± $17 101 vs $50905 ± $10062, P= .001), a mean difference of $6356. The mean differences were greatest for bed charges ($1642), laboratory charges ($1215), pharmacy ($989), and respiratory care ($582). Conclusion The economic impact of atrial fibrillation after coronary artery bypass grafting has been underestimated. PMID:12022486

Adult BMI and Access to Built Environment Resources in a High-Poverty, Urban Geography.

PubMed

Tung, Elizabeth L; Peek, Monica E; Makelarski, Jennifer A; Escamilla, Veronica; Lindau, Stacy T

2016-11-01

The purpose of this study is to examine the relationship between BMI and access to built environment resources in a high-poverty, urban geography. Participants (aged ≥35 years) were surveyed between November 2012 and July 2013 to examine access to common health-enabling resources (grocers, outpatient providers, pharmacies, places of worship, and physical activity resources). Survey data were linked to a contemporaneous census of built resources. Associations between BMI and access to resources (potential and realized) were examined using independent t-tests and multiple linear regression. Data analysis was conducted in 2014-2015. Median age was 53.8 years (N=267, 62% cooperation rate). Obesity (BMI ≥30) prevalence was 54.9%. BMI was not associated with potential access to resources located nearest to home. Nearly all participants (98.1%) bypassed at least one nearby resource type; half bypassed nearby grocers (realized access >1 mile from home). Bypassing grocers was associated with a higher BMI (p=0.03). Each additional mile traveled from home to a grocer was associated with a 0.9-higher BMI (95% CI=0.4, 1.3). Quality and affordability were common reasons for bypassing resources. Despite potential access to grocers in a high-poverty, urban region, half of participants bypassed nearby grocers to access food. Bypassing grocers was associated with a higher BMI. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

A multi-year analysis of spillway survival for juvenile salmonids as a function of spill bay operations at McNary Dam, Washington and Oregon, 2004-09

USGS Publications Warehouse

Adams, Noah S.; Hansel, Hal C.; Perry, Russell W.; Evans, Scott D.

2012-01-01

We analyzed 6 years (2004-09) of passage and survival data collected at McNary Dam to examine how spill bay operations affect survival of juvenile salmonids passing through the spillway at McNary Dam. We also examined the relations between spill bay operations and survival through the juvenile fish bypass in an attempt to determine if survival through the bypass is influenced by spill bay operations. We used a Cormack-Jolly-Seber release-recapture model (CJS model) to determine how the survival of juvenile salmonids passing through McNary Dam relates to spill bay operations. Results of these analyses, while not designed to yield predictive models, can be used to help develop dam-operation strategies that optimize juvenile salmonid survival. For example, increasing total discharge typically had a positive effect on both spillway and bypass survival for all species except sockeye salmon (Oncorhynchus nerka). Likewise, an increase in spill bay discharge improved spillway survival for yearling Chinook salmon (Oncorhynchus tshawytscha), and an increase in spillway discharge positively affected spillway survival for juvenile steelhead (Oncorhynchus mykiss). The strong linear relation between increased spill and increased survival indicates that increasing the amount of water through the spillway is one strategy that could be used to improve spillway survival for yearling Chinook salmon and juvenile steelhead. However, increased spill did not improve spillway survival for subyearling Chinook salmon and sockeye salmon. Our results indicate that a uniform spill pattern would provide the highest spillway survival and bypass survival for subyearling Chinook salmon. Conversely, a predominantly south spill pattern provided the highest spillway survival for yearling Chinook salmon and juvenile steelhead. Although spill pattern was not a factor for spillway survival of sockeye salmon, spill bay operations that optimize passage through the north and south spill bays maximized spillway survival for this species. Bypass survival of yearling Chinook salmon could be improved by optimizing conditions to facilitate bypass passage at night, but the method to do so is not apparent from this analysis because photoperiod was the only factor affecting bypass survival based on the best and only supported model. Bypass survival of juvenile steelhead would benefit from lower water temperatures and increased total and spillway discharge. Likewise, subyearling Chinook salmon bypass survival would improve with lower water temperatures, increased total discharge, and a uniform spill pattern.

Comparison of laparoscopic and open aortobifemoral bypass in the treatment of aortoiliac disease. Results of a contemporary series (2003-2009).

PubMed

Bruls, S; Quaniers, J; Tromme, P; Lavigne, J-P; Van Damme, H; Defraigne, J O

2012-01-01

The study objective was to describe and evaluate our single center (University Hospital Liège) experience with totally laparoscopic bypass surgery compared with conventional open surgery to treat aortoiliac occlusive disease. A retrospective database review of all patients undergoing aortobifemoral bypass for aortoiliac occlusive disease in our center, between 2003 and 2009, was performed. During this period, a total of 251 consecutive patients were identified. Among these patients, 95 underwent totally laparoscopic aortobifemoral bypass (group I) and 156 conventional open surgery (group II). Demographic data, operative data, postoperative recovery data, complications, two-year follow-up, morbidity and mortality were analysed according to the laparoscopic and conventional open group. Patients included 160 men and 91 women. The mean age was 61 years (range, 40 to 88 years) in both groups. Indications for surgery were invalidating claudication in 87%, rest pain in 7%, trophic disorders in 5%, impotence in 1.6% and digestive claudication in 1.2%. Prior to bypass surgery, 11 (11.6%) for the group I and 41 (26.3%) for the group II had undergone one or more abdominal surgical procedures. A transperitoneal and retrocolic approach was preferred in all laparoscopic procedures. Laparoscopic aortobifemoral bypass (LABF) required an operative time of 242 minutes (range, 129 to 465) and open aortobifemoral bypass (OABF), 200 minutes (range, 105 to 430). The mean aortic cross clamping time was 62 minutes in group I and 33 minutes in group II. Mean blood loss was more important in group II (1010 ml) than in group I (682 ml). The average length of hospital stay was 8.1 days for LABF compared with an average of 12 days for OABF. In 21 cases (20%) conversion to open surgery was necessary in the laparoscopic group. Systemic morbidity was significantly higher in the OABF group. Thirty-day postoperative mortality was 2% for group II. There was no hospital mortality in the laparoscopic group. Twenty nine patients were lost to follow-up and the mean follow-up was 23.5 months. Analysis of the results shows that laparoscopic aortobifemoral bypass for aortoiliac occlusive disease is a safe procedure. The statistically significant advantages observed in the majority of our patients were decreased blood loss, faster post-operative recovery and shorter hospital stay. In the two groups, late morbidity attributable to the bypass prosthesis was minimal compared with other causes.

Aspirin resistance in patients with hemodynamic cerebral ischemia undergoing extracranial-intracranial bypass surgery.

PubMed

Jussen, Daniel; Horn, Peter; Vajkoczy, Peter

2013-01-01

Aspirin (acetylsalicylic acid, ASA) is the treatment of choice for prevention of vascular events in symptomatic steno-occlusive cerebrovascular disease (CVD). Cerebral revascularization using standard extracranial-intracranial (EC-IC) bypass surgery may be used to revert hemodynamic compromise. Aspirin is prescribed as standard medication in order to avoid bypass failure. Accumulating evidence of an increased risk of major adverse clinical events led to this study, in which we aimed to assess the prevalence of aspirin resistance and prothrombotic disorders among patients scheduled for EC-IC bypass surgery, and the effectiveness of aspirin dose escalation. We prospectively screened patients with circumscribed high-grade stenosis or occlusion of brain-supplying vessels fulfilling the hemodynamic criteria for EC-IC bypass surgery for aspirin resistance using a platelet function analyzer (PFA-100®) test. We also determined their smoking habits and screened for prothrombotic disorders and comorbidities. The patients were divided into 2 major groups: group A had atherosclerotic steno-occlusive CVD and group B consisted of patients with nonatherosclerotic steno-occlusive CVD (moyamoya disease) and a subgroup of pediatric moyamoya patients (pediatric subgroup). Bypass patency was documented via digital subtraction angiography. Standard initial ASA dose applied was 100 mg/day. In cases of aspirin resistance, doses were increased and the PFA-100 test was repeated. A total of 56 patients were included over a time period of 6 months. In group A (n = 25), we found a ratio of 40% of patients with primary resistance to aspirin 100 mg/day. In contrast, in group B (n = 25), only 20% of the patients were resistant to aspirin 100 mg/day; in the pediatric population (n = 6), there was no primary aspirin resistance. After a dose escalation to 300 mg/day, the ratio of aspirin resistance was reduced to 20% in group A and to 0% in group B. Altogether 5 patients with atherosclerotic steno-occlusive CVD remained aspirin-resistant despite the dose escalation; 2 of them suffered an early bypass failure. Smoking habits and diabetes mellitus were positively correlated with aspirin resistance. Moreover, 25% of all patients had laboratory signs of a prothrombotic disorder, but this had no influence on aspirin response or bypass patency. Aspirin resistance is common in the population of patients with hemodynamic cerebral ischemia scheduled for cerebral revascularization. It may have an adverse impact on the outcome of surgery. Screening and treatment via dose escalation of aspirin is a straightforward and sensible routine for patients undergoing EC-IC bypass surgery. Copyright © 2013 S. Karger AG, Basel.

Structure-function analysis of ribonucleotide bypass by B family DNA replicases

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

Clausen, Anders R.; Murray, Michael S.; Passer, Andrew R.

2013-11-01

Ribonucleotides are frequently incorporated into DNA during replication, they are normally removed, and failure to remove them results in replication stress. This stress correlates with DNA polymerase (Pol) stalling during bypass of ribonucleotides in DNA templates. Here we demonstrate that stalling by yeast replicative Pols δ and ε increases as the number of consecutive template ribonucleotides increases from one to four. The homologous bacteriophage RB69 Pol also stalls during ribonucleotide bypass, with a pattern most similar to that of Pol ε. Crystal structures of an exonuclease-deficient variant of RB69 Pol corresponding to multiple steps in single ribonucleotide bypass reveal thatmore » increased stalling is associated with displacement of Tyr391 and an unpreferred C2´-endo conformation for the ribose. Even less efficient bypass of two consecutive ribonucleotides in DNA correlates with similar movements of Tyr391 and displacement of one of the ribonucleotides along with the primer-strand DNA backbone. These structure–function studies have implications for cellular signaling by ribonucleotides, and they may be relevant to replication stress in cells defective in ribonucleotide excision repair, including humans suffering from autoimmune disease associated with RNase H2 defects.« less

Closed-chest cardiopulmonary bypass and cardioplegia: basis for less invasive cardiac surgery.

PubMed

Peters, W S; Siegel, L C; Stevens, J H; St Goar, F G; Pompili, M F; Burdon, T A

1997-06-01

We developed a method of closed-chest cardiopulmonary bypass to arrest and protect the heart with cardioplegic solution. This method was used in 54 dogs and the results were retrospectively analyzed. Bypass cannulas were placed in the right femoral vessels. A balloon occlusion catheter was passed via the left femoral artery and positioned in the ascending aorta. A pulmonary artery vent was placed via the jugular vein. In 17 of the dogs retrograde cardioplegia was provided with a percutaneous coronary sinus catheter. Cardiopulmonary bypass time was 111 +/- 27 minutes (mean +/- standard deviation) and cardiac arrest time was 66 +/- 21 minutes. Preoperative cardiac outputs were 2.9 +/- 0.70 L/min and postoperative outputs were 2.9 +/- 0.65 L/min (p = not significant). Twenty-one-French and 23F femoral arterial cannulas that allowed coaxial placement of the ascending aortic balloon catheter were tested in 3 male calves. Line pressures were higher, but not clinically limiting, with the balloon catheter placed coaxially. Adequate cardiopulmonary bypass and cardioplegia can be achieved in the dog without opening the chest, facilitating less invasive cardiac operations. A human clinical trial is in progress.

U.S. Department of Energy FreedomCAR & Vehicle Technologies Program Oil Bypass Filter Technology Evaluation Fifth Quarterly Report October - December 2003

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

Larry Zirker; James Francfort

2004-02-01

This Oil Bypass Filter Technology Evaluation quarterly report (October-December 2003) details the ongoing fleet evaluation of an oil bypass filter technology by the Idaho National Engineering and Environmental Laboratory (INEEL) for the U.S. Department of Energy's FreedomCAR & Vehicle Technologies Program. Eight four-cycle diesel-engine buses used to transport INEEL employees on various routes have been equipped with oil bypass filter systems from the puraDYN Corporation. The bypass filters are reported to have engine oil filtering capability of <1 micron and a built-in additive package to facilitate extended oil-drain intervals. To date, the eight buses have accumulated 324,091 test miles. Thismore » represents an avoidance of 27 oil changes, which equate to 952 quarts (238 gallons) of new oil not conserved and therefore, 952 quarts of waste oil not generated. To validate the extended oil-drain intervals, an oil-analysis regime is used to evaluate the fitness of the oil for continued service by monitoring the presence of necessary additives, undesirable contaminants, and engine-wear metals. The test fleet has been expanded to include six Chevrolet Tahoe sport utility vehicles with gasoline engines.« less

California's Yolo Bypass: Evidence that flood control can be compatible with fisheries, wetlands, wildlife, and agriculture

USGS Publications Warehouse

Sommer, T.; Harrell, B.; Nobriga, M.; Brown, R.; Moyle, P.B.; Kimmerer, W.; Schemel, Laurence E.

2001-01-01

Unlike conventional flood control systems that frequently isolate rivers from ecologically-essential floodplain habitat, California's Yolo Bypass has been engineered to allow Sacramento Valley floodwaters to inundate a broad floodplain. From a flood control standpoint, the 24,000 ha leveed floodplain has been exceptionally successful based on its ability to convey up to 80% of the flow of the Sacramento River basin during high water events. Agricultural lands and seasonal and permanent wetlands within the bypass provide key habitat for waterfowl migrating through the Pacific Flyway. Our field studies demonstrate that the bypass seasonally supports 42 fish species, 15 of which are native. The floodplain appears to be particularly valuable spawning and rearing habitat for the splittail (Pogonichthys macrolepidotus), a federally-listed cyprinid, and for young chinook salmon (Oncorhynchus tshawytscha), which use the Yolo Bypass as a nursery area. The system may also be an important source to the downstream food web of the San Francisco Estuary as a result of enhanced production of phytoplankton and detrital material. These results suggest that alternative flood control systems can be designed without eliminating floodplain function and processes, key goals of the 1996 Draft AFS Floodplain Management Position Statement.

Clinical review: Aggressive management and extracorporeal support for drug-induced cardiotoxicity

PubMed Central

Baud, Frédéric J; Megarbane, Bruno; Deye, Nicolas; Leprince, Pascal

2007-01-01

Poisoning may induce failure in multiple organs, leading to death. Supportive treatments and supplementation of failing organs are usually efficient. In contrast, the usefulness of cardiopulmonary bypass in drug-induced shock remains a matter of debate. The majority of deaths results from poisoning with membrane stabilising agents and calcium channel blockers. There is a need for more aggressive treatment in patients not responding to conventional treatments. The development of new antidotes is limited. In contrast, experimental studies support the hypothesis that cardiopulmonary bypass is life-saving. A review of the literature shows that cardiopulmonary bypass of the poisoned heart is feasible. The largest experience has resulted from the use of peripheral cardiopulmonary bypass. However, a literature review does not allow any conclusions regarding the efficiency and indications for this invasive method. Indeed, the majority of reports are single cases, with only one series of seven patients. Appealing results suggest that further studies are needed. Determination of prognostic factors predictive of refractoriness to conventional treatment for cardiotoxic poisonings is mandatory. These prognostic factors are specific for a toxicant or a class of toxicants. Knowledge of them will result in clarification of the indications for cardiopulmonary bypass in poisonings. PMID:17367544

Coiling of a Ruptured Large Internal Carotid Artery Aneurysm via Extracranial-Intracranial Saphenous Vein Bypass Graft Just After Proximal Ligation of the Internal Carotid Artery.

PubMed

Tajima, Hayato; Araki, Yoshio; Izumi, Takashi; Nishihori, Masahiro; Okamoto, Sho; Wakabayashi, Toshihiko

2017-02-01

Combined direct and endovascular surgery has been performed to treat large to giant internal carotid artery (ICA) aneurysms. This report describes successful treatment of a large ICA aneurysm by coiling of the aneurysm via an extracranial-intracranial saphenous vein (SV) graft just after bypass and ICA proximal ligation. A 66-year-old woman presented with a left ICA supraclinoid aneurysm with progressive visual field defect and impaired visual acuity in the left eye. While waiting for scheduled surgery, she experienced a subarachnoid hemorrhage. An extracranial-intracranial high-flow bypass using an SV graft and proximal ligation of the ICA were performed. Coiling of the aneurysm was immediately performed successfully via the SV bypass graft. The patient experienced no new neurologic deficit after this treatment. Follow-up radiologic evaluations using magnetic resonance imaging and magnetic resonance angiography revealed complete aneurysm occlusion. Aneurysm coiling via an extracranial-intracranial SV bypass graft could offer an alternative when an antegrade access route to the ICA is not used because of prior parent artery ligation. Copyright © 2016 Elsevier Inc. All rights reserved.

Platelet mapping as part of modified thromboelastography (TEG®) in patients undergoing cardiac surgery and cardiopulmonary bypass.

PubMed

Weitzel, N S; Weitzel, L B; Epperson, L E; Karimpour-Ford, A; Tran, Z V; Seres, T

2012-10-01

The platelet-mapping assay of the thromboelastograph was used to measure platelet aggregation and to examine the effect of cardiopulmonary bypass on multiple platelet receptors and the role of altered receptor activity in postoperative bleeding. The percentage platelet aggregation for collagen, adenosine diphosphate and arachidonic acid was measured in 40 patients divided post-hoc into high- or low-bleeding groups depending on postoperative 24-h chest tube output. Platelet aggregation was lower after cardiopulmonary bypass compared to before it using collagen (mean (SD) 45 (25) vs 19 (12)%, p<0.001), adenosine diphosphate (76 (23) vs 35 (24)%, p<0.001), and arachidonic acid (61 (33) vs 31 (35)%, p<0.001). Only platelet aggregation as measured using collagen pre- and post-cardiopulmonary bypass was significantly less in the high- compared to the low-bleeding group. This finding was significantly correlated with the 24-h chest tube drainage, and it predicted postoperative bleeding with a sensitivity of 83% and a specificity of 68%. Therefore, platelet aggregation is reduced following cardiopulmonary bypass, and this may play a role in predicting postoperative blood loss. Anaesthesia © 2012 The Association of Anaesthetists of Great Britain and Ireland.

Specialty Article: so You Think You Got a Bypass? A Case Series of Adventures in Bariatric Surgery.

PubMed

Wang, Eugene Y; Shope, Timothy R

2018-05-01

To raise awareness for surgeons encountering bariatric patients with anatomy that deviates from the standard Roux-en-Y gastric bypass (RYGB). This is a single-institution retrospective case series over 12 years (2003-2014) involving patients who believed they received RYGBs, but actually did not. Data was obtained reviewing physician encounters, imaging, and operative reports. There were six cases with confusing clinical pictures, found to have aberrant RYGB anatomy: (1) gastric bypass with jejuno-jejunostomy only without gastrojejunostomy, (2) distal partial vertical gastrectomy without expected prosthetic band, (3) inverse vertical banded gastroplasty, (4) non-divided gastric bypass with no gastrojejunostomy, (5) 20-cm Roux limb, with gastro-gastric fistula, and (6) 200-cm bilio-pancreatic limb similar to the traditional Scopinaro procedure. There are cases of "Roux-en-Y gastric bypasses" that have no resemblance to the named procedure at all. Adjunctive upper gastrointestinal studies and upper endoscopies help surgeons make diagnoses that are incongruent with the surgical history. It is important to keep in mind that there could be anatomic or surgical variations which were born out of necessity or based on other surgeons' creativities.

Environmental impact case study : Martinsville bypass.

DOT National Transportation Integrated Search

1971-01-01

At the request of the Environmental Quality Division, the Environmental and Economics Section of the Virginia Highway Research Council conducted an environmental impact study of the proposed Route 220 bypass around Martinsville. This evaluation of th...

77 FR 3455 - Privacy Act of 1974; System of Records-Migrant Education Bypass Program Student Database

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-24

... Student Database AGENCY: Office of Elementary and Secondary Education, Department of Education. ACTION... entitled ``Migrant Education Bypass Program Student Database (MEBPSD)'' (18-14-06). The Secretary has...

[Hypoglycaemia and hypocalcaemia in a gastric bypass-operated patient with high alcohol consumption and colectomia].

PubMed

Worm, Dorte; Naver, Lars S; Hansen, Dorte L

2015-04-13

The combination of gastric bypass, colectomia, lack of substitution with minerals and vitamins, and alcohol consumption led to severe complications in a 57-year-old man. He was submitted to different hospitals 25 times and seen in polyclinics 39 times with no improvement in symptoms of postprandial neurohypoglycaemia, ortostatic hypotension and pronounced hypocalcaemia. The importance of frequent controls after gastric bypass in centres with specialists knowing the common complications after the operation and the need for nutritionel supplements is hereby emphasised.

Collaborative Research on the Ultra High Bypass Ratio Engine Cycle to Reduce Noise, Emissions and Fuel Consumption

NASA Technical Reports Server (NTRS)

Hughes, Christopher

2008-01-01

A pictorial history of NASA development of advanced engine technologies for reducing environmental emissions and increasing performance from the 1970s to present is presented. The goals of the Subsonic Fixed Wing Program portion of the NASA Fundamental Aeronautics Program are addressed, along with the areas of investigation currently being pursued by the Ultra High Bypass Partnership Element of the Subsonic Fixed Wing Program to meet the goals. Ultra High Bypass cycle research collaboration successes with Pratt & Whitney are presented.

Construct exploit constraint in crash analysis by bypassing canary

NASA Astrophysics Data System (ADS)

Huang, Ning; Huang, Shuguang; Huang, Hui; Chang, Chao

2017-08-01

Selective symbolic execution is a common program testing technology. Developed on the basis of it, some crash analysis systems are often used to test the fragility of the program by constructing exploit constraints, such as CRAX. From the study of crash analysis based on symbolic execution, this paper find that this technology cannot bypass the canary stack protection mechanisms. This paper makes the improvement uses the API hook in Linux. Experimental results show that the use of API hook can effectively solve the problem that crash analysis cannot bypass the canary protection.

Gas Turbine Engine Having Fan Rotor Driven by Turbine Exhaust and with a Bypass

NASA Technical Reports Server (NTRS)

Suciu, Gabriel L. (Inventor); Chandler, Jesse M. (Inventor)

2016-01-01

A gas turbine engine has a core engine incorporating a core engine turbine. A fan rotor is driven by a fan rotor turbine. The fan rotor turbine is in the path of gases downstream from the core engine turbine. A bypass door is moveable from a closed position at which the gases from the core engine turbine pass over the fan rotor turbine, and moveable to a bypass position at which the gases are directed away from the fan rotor turbine. An aircraft is also disclosed.

Compliance Testing of Grissom AFB Central Heating Plant Coal-Fired Boilers 3 and 5, Grissom AFB, Indiana

DTIC Science & Technology

1988-06-01

common breeching and can be routed to the wet-scrubber or to a bypass stack. The scrubber is a double-alkali flue - gas desulfurization system using soda...Illustrations Figure Title Page 1 View of Scrubber and Bypass Stacks 3 2 Scrubber Stacks 4 3 Bypass Stack 5 4 Flue Gas Flow Diagram 6 5 ORSAT Sampling...of gases and to provide a positive static pressure at flue gas exhaust discharge points. The ash system pneumatically removes ash from bottom-ash

Temporary ventricular overdrive pacing for electrical storm after coronary artery bypass grafting.

PubMed

Yoshida, Toshihito; Naito, Yuji; Nishimura, Kuniharu

2011-11-01

A 57-year-old man who had been receiving chemotherapy for multiple myeloma complained of chest pain and was diagnosed with coronary artery disease. Coronary artery bypass grafting without cardiopulmonary bypass was performed smoothly, and extubation was done in the operating room. The next evening, cluster of ventricular tachycardia and fibrillation triggered by ventricular premature contractions occurred and required multiple electrical defibrillations. Despite intravenous administration of lidocaine, amiodarone, magnesium, and β-blocker, the storm sustained and was suppressed only by temporary ventricular overdrive pacing. He was discharged on foot.

Interrogation of possible imaging conditions for radiation sensitive metal organic frameworks in transmission electron microscopes

NASA Astrophysics Data System (ADS)

Patel, Harinkumar Rajendrabhai

One of the main area of research currently in air-breathing propulsion is increasing the fuel efficiency of engines. Increasing fuel efficiency of an air-breathing engine will be advantageous for civil transport as well as military aircraft. This objective can be achieved in several ways. Present design models are developed based on their uses: commercial transport, high range rescue aircraft, military aircraft. One of the main property of military aircraft is possessing high thrust but increasing fuel efficiency will also be advantageous resulting in more time in combat. Today's engine design operates best at their design point and has reduced thrust and high fuel consumption values in off-design. The adaptive cycle engine concept was introduced to overcome this problem. The adaptive cycle engine is a variable cycle engine concept equipped with an extra bypass (3rd bypass) stream. This engine varies the bypass ratio and the fan pressure ratio, the two main parameters affecting thrust and fuel consumption values of the engine. In cruise, more flow will flow through the third stream resulting in the high bypass engine giving lower fuel consumption. on the other hand, the engine will act as a low bypass engine producing more thrust by allowing more air to flow through core while in combat. The simulation of this engine was carried out using the Numerical Propulsion System Simulation (NPSS) software. The effect of the bypass ratio and the fan pressure ratio along with Mach number were studied. After the parametric variation study, the mixture configuration was also studied. Once the effect of the parameters were understood, the best design operating point configuration was selected and then the engine performance for off-design was calculated. Optimum values of bypass ratio and fan pressure ratio were also obtained for each altitude selected for off-design performance.

Oxygen delivery during cardiopulmonary bypass (and renal outcome) using two systems of extracorporeal circulation: a retrospective review.

PubMed

Bennett, Mark J; Rajakaruna, Cha; Bazerbashi, Samer; Webb, Gerry; Gomez-Cano, Mayam; Lloyd, Clinton

2013-06-01

To investigate the combined influence of blood flow and haemodilution with either a miniaturized (Mini-CPB) or a conventional cardiopulmonary bypass (C-CPB) circuit on average oxygen delivery during bypass. The influence of this on clinical outcome, particularly renal dysfunction after routine coronary artery bypass surgery (CABG), was measured. Retrospective analysis in two groups of 160 patients based on the surgeon's preference for bypass circuit. We compared consecutive patients undergoing isolated CABG surgery by two surgeons using Mini-CPB with a matched cohort of patients, from the same period, undergoing isolated CABG surgery by four other surgeons using a C-CPB. No trial-related intervention occurred. Data on bypass circuit parameters and clinical outcomes were acquired from routinely collected data sources. Average cardiopulmonary bypass pump flow was significantly lower with Mini-CPB compared with C-CPB. Mini-CPB resulted in significantly less haemodilution. The resultant calculated average oxygen delivery provided by the two systems was the same. Percentage change in plasma creatinine was significantly and inversely related to the oxygen delivery during CPB. There was no difference in percentage change in plasma creatinine between groups. The risk of having Acute Kidney Injury Network (AKIN) score ≥ 1 increased 1% for every 1 ml min(-1) m(-2) decrease in oxygen delivery (P = 0.0001, OR 0.990, 95% CI 0.984-0.995). Despite aiming for the same target pump flow, periodic limitations of venous return to the pump resulted in a significant reduction in average flow delivered to the patient by Mini-CPB. Less haemodilution compensated for this reduction, so that the average oxygen delivery was the same. The association between oxygen delivery and postoperative change in plasma creatinine was evident in both groups. Further work to understand whether there is a particular cohort of patients who benefit (or are put at risk) by one method of CPB vs the other is warranted.

An alternative arrangement of metered dosing fluid using centrifugal pump

NASA Astrophysics Data System (ADS)

Islam, Md. Arafat; Ehsan, Md.

2017-06-01

Positive displacement dosing pumps are extensively used in various types of process industries. They are widely used for metering small flow rates of a dosing fluid into a main flow. High head and low controllable flow rates make these pumps suitable for industrial flow metering applications. However their pulsating flow is not very suitable for proper mixing of fluids and they are relatively more expensive to buy and maintain. Considering such problems, alternative techniques to control the fluid flow from a low cost centrifugal pump is practiced. These include - throttling, variable speed drive, impeller geometry control and bypass control. Variable speed drive and impeller geometry control are comparatively costly and the flow control by throttling is not an energy efficient process. In this study an arrangement of metered dosing flow was developed using a typical low cost centrifugal pump using bypass flow technique. Using bypass flow control technique a wide range of metered dosing flows under a range of heads were attained using fixed pump geometry and drive speed. The bulk flow returning from the system into the main tank ensures better mixing which may eliminate the need of separate agitators. Comparative performance study was made between the bypass flow control arrangement of centrifugal pump and a diaphragm type dosing pump. Similar heads and flow rates were attainable using the bypass control system compared to the diaphragm dosing pump, but using relatively more energy. Geometrical optimization of the centrifugal pump impeller was further carried out to make the bypass flow arrangement more energy efficient. Although both the systems run at low overall efficiencies but the capital cost could be reduced by about 87% compared to the dosing pump. The savings in capital investment and lower maintenance cost very significantly exceeds the relatively higher energy cost of the bypass system. This technique can be used as a cost effective solution for industries in Bangladesh and have been implemented in two salt iodization plants at Narayangang.

Potential Impacts of Climate Change on Sediment - Water Exchange of Mercury in a Managed Flood Conveyance System

NASA Astrophysics Data System (ADS)

Heim, W. A.; Stephenson, M.; Negrey, J.; Gill, G. A.; Coale, K. H.; DiGiorgio, C.; Harris, R. C.

2016-12-01

Yolo Bypass is the largest flood bypass in the Sacramento Valley, California. During high flow flood events water is diverted into the Yolo Bypass from the Sacramento River to control river stage and protect the cities of Sacramento, West Sacramento, and Davis from flooding. Climate change projections for the Yolo Bypass indicate the risk of flooding will increase. An increase in flooding would result in increased connectivity of the flood plain with downstream habitats as well as provide conditions favorable for in situ production of methylmercury (MeHg). Conversion of inorganic mercury (Hg) to the more toxic organic form MeHg in freshwater systems is generally accepted to be mediated by bacteria activity. There are a number of environmental variables (organic carbon, sulfate, oxygen) and conditions (temperature, porosity, soil type) that could influence the net production of MeHg and its ultimate release into the water column. This study investigated sediment-water exchange of both Hg and MeHg from the following habitat types in the Yolo Bypass: wild rice, white rice, seasonal wetlands, irrigated pasture, non-irrigated pasture, fallow land, farm land, freshwater tidal wetland, and agricultural drain. Two methods were used to determine sediment-water exchange of inorganic and organic mercury; first a direct assessment using incubated cores and second, modeling the sediment-water exchange from measurements of interstitial pore water concentration gradients. Results indicate habitat type, land use, and flooding influence Hg and MeHg fluxes. If flooding frequency increases in the Yolo Bypass mercury fluxes are expected to increase resulting in an increase in Hg load to downstream habitats and an increase in biotic exposure to MeHg in the system. A next step will be to utilize data generated from this study in the Dynamic Mercury Cycling Model (D-MCM) which will be used to improve our understanding of factors controlling production and transport of Hg and MeHg in the Yolo Bypass.

Decreased contractile response of peripheral arterioles to serotonin after CPB in patients with diabetes.

PubMed

Sabe, Sharif A; Feng, Jun; Liu, Yuhong; Scrimgeour, Laura A; Ehsan, Afshin; Sellke, Frank W

2018-05-11

Regulation of coronary vasomotor tone by serotonin is significantly changed after cardioplegic arrest and reperfusion. The current study investigates whether cardiopulmonary bypass may also affect peripheral arteriolar response to serotonin in patients with or without diabetes. Human peripheral microvessels (90-180 µm diameter) were dissected from harvested skeletal muscle tissues from diabetic and non-diabetic patients before and after cardiopulmonary bypass and cardiac surgery (n = 8/group). In vitro contractile response to serotonin was assessed by videomicroscopy in the presence or absence of serotonin alone (10 -9 -10 -5 M) or combined with the selective serotonin 1B receptor (5-HT1B) antagonist, SB224289 (10 -6 M). 5-HT1A/1B protein expression in the skeletal muscle was measured by Western-blot and immunohistochemistry. There were no significant differences in contractile response of peripheral arterioles to serotonin (10 -5 M) pre-cardiopulmonary bypass between diabetic and non-diabetic patients. After cardiopulmonary bypass, contractile response to serotonin was significantly impaired in both diabetic and non-diabetic patients compared to their pre-cardiopulmonary bypass counterparts (P < .05). This effect was more pronounced in diabetic patients than non-diabetic patients (P < .05 versus non-diabetic). The contractile response to serotonin was significantly inhibited by the 5-HT1B antagonist in both diabetic and non-diabetic vessels (P < .05 versus serotonin alone). There were no significant differences in the expression/distribution of 5-HT1A/1B between non-diabetic and diabetic groups or between pre- versus post- cardiopulmonary bypass vessels. Cardiopulmonary bypass is associated with decreased contractile response of peripheral arterioles to serotonin and this effect was exaggerated in the presence of diabetes. Serotonin-induced contractile response of the peripheral arterioles was via 5-HT1B in both diabetic and non-diabetic patients. Copyright © 2018 Elsevier Inc. All rights reserved.

Cardiovascular risk profile before coronary artery bypass graft surgery in relation to depression and anxiety disorders: An age and sex propensity matched study.

PubMed

Tully, Phillip J; Newland, Richard F; Baker, Robert A

2015-02-01

The cardiovascular risk profile and postoperative morbidity outcomes of anxiety disorder patients undergoing coronary artery bypass surgery is not known. In a cross-sectional design, 114 consecutive coronary artery bypass graft surgery patients were evaluated to create four matched groups (30 with anxiety disorder, 27 with depression disorder and 57 age-sex matched coronary artery bypass surgery control patients with no depression or anxiety disorder). By comparison to non-depression disorder age-sex matched controls, depressed patients presented for coronary artery bypass surgery with significantly greater myocardial inflammatory markers (Troponin T>02, 33.3% vs. 11.1%, p=.03), metabolic risk (body surface area>35 (22.2% vs. 0%, p=.03), comorbid cardiovascular risk (peripheral vascular disease 18.5% vs. 0%, p=.05). Depressed patients also recorded longer intraoperative time at higher temperatures >37°C on cardiopulmonary bypass (11.1 ± 9.0 vs. 6.0 ± 4.9, p<005) and had higher maximum postoperative Troponin T (.44 ± .2 vs. .28 ± .1, p=.03). Patients with anxiety disorder on the other hand presented with significantly higher Creatinine Kinase-Muscle Brain (5 IQR 4-5 ng/ml vs. 4 IQR 3-4 ng/ml, p=.04), higher intraoperative glucose levels (7.8 ± 2.5 mmol/l vs. 7.0 ± 1.2 mmol/l, p=.05), and received fewer grafts (2.1 ± .9 vs. 2.5 ± .9 p=.04). A differential cardiovascular risk profile and postoperative outcome was observed dependent on anxiety and depression disorder status. There were few modifiable cardiovascular risk factors at the time of surgery other than psychiatric status, perioperative management of depression and anxiety may have promise to reduce further cardiac morbidity after coronary artery bypass surgery. Copyright © 2014. Published by Elsevier Ltd.

Early changes in myocardial repolarization and coronary perfusion after cardiopulmonary bypass surgery for ASD repair in children.

PubMed

Aburawi, Elhadi H; Souid, Abdul-Kader; Liuba, Petru; Zoubeidi, Taoufik; Pesonen, Erkki

2013-09-10

In adults, impaired myocardial repolarization and increased risk of arrhythmia are known consequences of open heart surgery. Little is known, however, about post-operative consequences of cardiopulmonary bypass surgery in children. The aim of this study was to assess ventricular repolarization and coronary perfusion after bypass surgery for atrial septal defect (ASD) repair in children. Twelve patients with ASD were assessed one day before and 5-6 days after ASD repair. Myocardial repolarization (corrected QT interval, QTc, QT dispersion, QTd, and PQ interval) was determined on 12-lead electrocardiograms. Coronary flow in proximal left anterior descending artery (peak flow velocity in diastole, PFVd) was assessed by transthoracic Doppler echocardiography. Ten of the 12 (83%) children had normal myocardial repolarization before and after surgery. After surgery, QTc increased 1-9% in 5 (42%) patients, decreased 2-11% in 5 (42%) patients and did not change in 2 (16%) patients. Post-op QTc positively correlated with bypass time (R=0.686, p=0.014) and changes in PFVd (R=0.741, p=0.006). After surgery, QTd increased 33-67% in 4 (33%) patients, decreased 25-50% in 6 patients (50%) and did not change in 2 (16%) patients. After surgery, PQ interval increased 5-30% in 4 (33%) patients, decreased 4-29% in 6 (50%) patients and did not change in 1 (8%) patient. Post-op PQ positively correlated with bypass time (R=0.636, p=0.027). As previously reported, PFVd significantly increased after surgery (p<0.001). Changes in QTc, PQ and PFVd are common in young children undergoing surgery for ASD repair. Post-op QTc significantly correlates with bypass time, suggesting prolonged cardiopulmonary bypass may impair ventricular repolarization. Post-op QTc significantly correlates with PFVd changes, suggesting increased coronary flow may also impair ventricular repolarization. The clinical significance and reversibility of these alternations require further investigations.

Battery Cell By-Pass Circuit

NASA Technical Reports Server (NTRS)

Mumaw, Susan J. (Inventor); Evers, Jeffrey (Inventor); Craig, Calvin L., Jr. (Inventor); Walker, Stuart D. (Inventor)

2001-01-01

The invention is a circuit and method of limiting the charging current voltage from a power supply net work applied to an individual cell of a plurality of cells making up a battery being charged in series. It is particularly designed for use with batteries that can be damaged by overcharging, such as Lithium-ion type batteries. In detail. the method includes the following steps: 1) sensing the actual voltage level of the individual cell; 2) comparing the actual voltage level of the individual cell with a reference value and providing an error signal representative thereof; and 3) by-passing the charging current around individual cell necessary to keep the individual cell voltage level generally equal a specific voltage level while continuing to charge the remaining cells. Preferably this is accomplished by by-passing the charging current around the individual cell if said actual voltage level is above the specific voltage level and allowing the charging current to the individual cell if the actual voltage level is equal or less than the specific voltage level. In the step of bypassing the charging current, the by-passed current is transferred at a proper voltage level to the power supply. The by-pass circuit a voltage comparison circuit is used to compare the actual voltage level of the individual cell with a reference value and to provide an error signal representative thereof. A third circuit, designed to be responsive to the error signal, is provided for maintaining the individual cell voltage level generally equal to the specific voltage level. Circuitry is provided in the third circuit for bypassing charging current around the individual cell if the actual voltage level is above the specific voltage level and transfers the excess charging current to the power supply net work. The circuitry also allows charging of the individual cell if the actual voltage level is equal or less than the specific voltage level.

1. PLENUM INTERIOR, SHOWING HEATING COILS AND BYPASS Hot ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. PLENUM INTERIOR, SHOWING HEATING COILS AND BY-PASS - Hot Springs National Park, Bathhouse Row, Fordyce Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

Tests of by-pass diodes at cryogenic temperatures for the KATRIN magnets

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

Gil, W.; Bolz, H.; Jansen, A.

The Karlsruhe Tritium Neutrino experiment (KATRIN) requires a series of superconducting solenoid magnets for guiding beta-electrons from the source to the detector. By-pass diodes will operate at liquid helium temperatures to protect the superconducting magnets and bus bars in case of quenches. The operation conditions of the by-pass diodes depend on the different magnet systems of KATRIN. Therefore, different diode stacks are designed with adequate copper heat sinks assuming adiabatic conditions. The by-pass diode stacks have been submitted to cold tests both at liquid nitrogen and liquid helium temperatures for checking operation conditions. This report presents the test set upmore » and first results of the diode characteristics at 300 K and 77 K, as well as of endurance tests of the diode stacks at constant current load at 77 K and 4.2 K.« less

Current Bypassing Properties by Thermal Switch for PCS Application on NMR/MRI HTS Magnets

NASA Astrophysics Data System (ADS)

Kim, S. B.; Takahashi, M.; Saito, R.; Park, Y. J.; Lee, M. W.; Oh, Y. K.; Ann, H. S.

We develop the compact NMR/MRI device using high temperature superconducting (HTS) wires with the persistent current mode operating. So, the joint techniques between 2G wires are very important issue and many studies have been carried out. Recently, the Kbigdot JOINS, Inc. has developed successfully the high performance superconducting joints between 2G wires by partial melting diffusion and oxygenation annealing process [1]. In this study, the current bypassing properties in a loop-shaped 2G wire are measured experimentally to develop the permanent current switch (PSC). The current bypassing properties of loop-shaped test coil wound with 2G wire (GdBCO) are evaluated by measured the self-magnetic field due to bypassed current by Hall sensors. The strain gauge was used as heater for persistent current switch, and thermal properties against various thermal inputs were investigated experimentally.

Intratracheal Milrinone Bolus Administration During Acute Right Ventricular Dysfunction After Cardiopulmonary Bypass.

PubMed

Gebhard, Caroline Eva; Desjardins, Georges; Gebhard, Cathérine; Gavra, Paul; Denault, André Y

2017-04-01

To evaluate intratracheal milrinone (tMil) administration for rapid treatment of right ventricular (RV) dysfunction as a novel route after cardiopulmonary bypass. Retrospective analysis. Single-center study. The study comprised 7 patients undergoing cardiac surgery who exhibited acute RV dysfunction after cardiopulmonary bypass. After difficult weaning caused by cardiopulmonary bypass-induced acute RV dysfunction, milrinone was administered as a 5-mg bolus inside the endotracheal tube. RV function improvement, as indicated by decreasing pulmonary artery pressure and changes of RV waveforms, was observed in all 7 patients. Adverse effects of tMil included dynamic RV outflow tract obstruction (2 patients) and a decrease in systemic mean arterial pressure (1 patient). tMil may be an effective, rapid, and easily applicable therapeutic alternative to inhaled milrinone for the treatment of acute RV failure during cardiac surgery. However, sufficiently powered clinical trials are needed to confirm these findings. Copyright © 2017 Elsevier Inc. All rights reserved.

A randomized trial of the topical effect of antifibrinolytic epsilon aminocaproic Acid on coronary artery bypass surgery without cardiopulmonary bypass.

PubMed

Gurian, Danilo Bortolotto; Meneghini, Adriano; Abreu, Luiz Carlos de; Murad, Neif; Matos, Leandro Luongo de; Pires, Adilson Casemiro; Valenti, Vitor E; Breda, João Roberto

2014-09-01

We assessed the effect of the topical application of epsilon-aminocaproic antifibrinolytic acid (EACA) on the pericardium of patients submitted to coronary artery bypass graft (CABG) without the use of cardiopulmonary bypass (CPB). This is a prospective, randomized, and double-blind study. We evaluated 26 patients with chronic coronary heart disease indicated for CABG without CPB (EACA and placebo groups). The analysis of the postoperative hematological results showed no difference between groups in hemoglobin and hematocrit. There was no difference between the groups regarding the postoperative bleeding through the drains in the first 24 hours, 48 hours, and accumulated loss until removal of drains. The use of EACA in patients undergoing CABG without CPB presented no difference in the reduction of the amount of bleeding and the need for blood transfusions. © The Author(s) 2013.

Laparoscopic gastric bypass with subtotal gastrectomy for a super-obese patient with Biermer anemia.

PubMed

Sodji, Maxime; Sebag, Frédéric A; Catheline, Jean Marc

2007-08-01

Laparoscopic Roux-en-Y gastric bypass (RYGBP) is a common procedure for morbid obesity. After RYGBP, the bypassed stomach is unavailable for follow-up. Biermer anemia is an autoimmune atrophic gastritis inducing vitamin B12 deficiency and it is a risk factor for gastric carcinoma. A 41-year-old woman with a long history of morbid obesity presented with a BMI of 56 kg/m2. She had anemia (Hb 9.9 g/dL), and atrophic gastritis was found endoscopically. We performed a laparoscopic RYGBP with subtotal gastrectomy, to avoid the risk of gastric carcinoma in the bypassed stomach. The patient was discharged 9 days after the operation without complication. At 18 months follow-up, her BMI was 39 kg/m2 (50% excess weight loss). Laparoscopic RYGBP with subtotal gastrectomy is a safe treatment for morbid obesity, which should be considered for patients with a risk factor for gastric carcinoma.

Long-Term Follow-Up for a Giant Basilar Trunk Aneurysm Surgically Treated by Proximal Occlusion and External Carotid Artery to Posterior Cerebral Artery Bypass Using a Saphenous Vein Graft.

PubMed

Yanagisawa, Toshiharu; Kinouchi, Hiroyuki; Sasajima, Toshio; Shimizu, Hiroaki

2016-11-01

The authors describe a case of a basilar trunk aneurysm with long-term follow-up after successful bypass and proximal occlusion. A 64-year-old woman had a giant aneurysm of the basilar trunk and underwent external carotid artery-to-posterior cerebral artery vein graft bypass surgery and proximal clipping of the basilar artery, which was followed by low-dose aspirin (100 mg/d) treatment. No ischemic symptoms and lesions developed and the thrombosed aneurysm was stable during 11 years of follow-up. An extracranial-intracranial high flow bypass combined with immediate proximal occlusion and aspirin administration may be an acceptable treatment option for patients with giant posterior circulation aneurysms. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

Endovascular aneurysm exclusion along a femorodistal venous bypass in active Behçet's disease.

PubMed

Gretener, Silvia B; Do, Dai-Do; Baumgartner, Iris; Dinkel, Hans-Peter; Schmidli, Jürg; Birrer, Manuela

2002-10-01

To report the endovascular repair of dual aneurysms along a femorodistal venous bypass graft in a patient with Behçet's disease. A 55-year-old man of middle European ancestry with Behçet's disease had dual aneurysms evolve along the proximal segment of a femorodistal venous bypass that had been implanted 2.5 years earlier for recurrent false aneurysm formation. Owing to the lack of suitable venous conduits and the active nature of the disease, the aneurysms were successfully excluded with overlapping Hemobahn and Jostent endografts; the immunosuppressive therapy was intensified. Rupture of the aneurysms was successfully prevented, but the stent-grafts thrombosed 6 weeks later owing to exacerbation of the underlying disease. Endovascular exclusion of aneurysm in venous bypass grafts in Behçet's disease is feasible. Although the stent-grafts thrombosed, they did prevent rupture of the aneurysms.

Heterotopic pancreas in excluded stomach diagnosed after gastric bypass surgery

PubMed Central

2013-01-01

Background Heterotopic pancreas is defined as finding of pancreatic tissue without anatomic and vascular continuity with the normal pancreas. Heterotopic pancreas is a rare condition difficult to diagnose and with controversial clinical management. Case presentation We describe a 43 year old female patient previously submitted to laparoscopic gastric bypass for primary treatment of morbid obesity; 5 years later, the patient was discovered to have a mass in the antrum of the excluded stomach that was found to be heterotopic pancreatic tissue. Before gastric bypass surgery, the presence of the pancreatic mass in the gastric wall was unnoticed in the imagiologic records. Conclusion This is the first reported case of pancreatic heterotopy diagnosed in the excluded stomach after gastric bypass. A putative role of incretin hormones in mediating pancreatic cell hyperplasia of heterotopic pancreatic remnants should be considered an additional hypothesis that requires further research. PMID:24267291

NASA / Pratt and Whitney Collaborative Partnership Research in Ultra High Bypass Cycle Propulsion Concepts

NASA Technical Reports Server (NTRS)

Hughes, Chris; Lord, Wed

2008-01-01

Current collaborative research with Pratt & Whitney on Ultra High Bypass Engine Cycle noise, performance and emissions improvements as part of the Subsonic Fixed Wing Project Ultra High Bypass Engine Partnership Element is discussed. The Subsonic Fixed Wing Project goals are reviewed, as well as their relative technology level compared to previous NASA noise program goals. Progress toward achieving the Subsonic Fixed Wing Project goals over the 2008 fiscal year by the UHB Partnership in this area of research are reviewed. The current research activity in Ultra High Bypass Engine Cycle technology, specifically the Pratt & Whitney Geared Turbofan, at NASA and Pratt & Whitney are discussed including the contributions each entity bring toward the research project, and technical plans and objectives. Pratt & Whitney Geared Turbofan current and future technology and business plans are also discussed, including the role the NASA SFW UHB partnership plays toward achieving those goals.

Timing of pregnancy after gastric bypass-a national register-based cohort study.

PubMed

Kjær, Mette Mandrup; Nilas, Lisbeth

2013-08-01

Current recommendations suggest postponing pregnancy by at least 1 year after gastric bypass. During the first postoperative year, women are in a catabolic phase with a rapid weight loss which may increase the risk of adverse pregnancy and neonatal outcomes. This study tested the hypothesis that the risk of adverse pregnancy and neonatal outcomes is increased in women who conceive during the first year after gastric bypass surgery. This is a national register-based cohort study covering all Danish deliveries during 2004-2010 in women with prior Roux-en-Y gastric bypass surgery. Only the first postoperative birth was included. The risk of adverse pregnancy and neonatal outcomes was compared between women who conceived within the first postoperative year and women who conceived later. Data were extracted from the Danish National Patient Registry and The Danish Medical Birth Register. Of 286 women who had a singleton delivery after Roux-en-Y gastric bypass surgery, 158 women conceived within the first year and 128 later. There was no statistically significant difference (p > 0.05) between the two groups regarding neonatal birth weight, gestational age, risk of preeclampsia, gestational diabetes mellitus, labor induction, cesarean section, postpartum hemorrhage (>500 ml), preterm birth (before 37 weeks), small for gestational age, large for gestational age, or Apgar score (5 min ) below 7, or in the need of neonatal intensive care. This study showed no evidence to support a recommendation to delay pregnancy until after the first postoperative year. At present, the optimal time for pregnancy after gastric bypass is unknown.

Vascular connector devices increase the availability of minimally invasive cardiac surgery to ischemic heart patients.

PubMed

Ramchandani, M; Bedeir, K

2011-01-01

The revival of off-pump cardiac surgery and the exploration of less invasive techniques for coronary artery bypass grafting, have lead to an increasing technical difficulty, as compared to conventional surgery using cardiopulmonary bypass. The moving target vessel in off-pump coronary artery bypass surgery, as well as the increasingly limited space in minimally invasive cardiac surgery were not convenient to many surgeons, a fact that lead many surgeons to deprive their patients the potential benefits of these techniques. Since the 1950's, surgeons have attempted to make the anastomotic procedure less cumbersome and less time consuming. Many creative ideas and devices were made, but for many different reasons, they eventually faded away. Since then, hand-sewn anastomoses have been the standard of care in coronary artery bypass grafting. Today, with the obvious need for a facilitated and fast coronary anastomosis, interest in these anastomotic devices has been re-awakened. The exact geometry, physiology and dynamics of the perfect anastomosis have thus been studied, in an attempt to provide an understanding of reasons behind anastomosis and graft failure after coronary artery bypass surgery, and eventually design the best performing device. These devices would allow for a faster, more accurate and a more reproducible coronary anastomosis using minimally invasive techniques. Also, due to a short learning curve, the standardization of percutaneous devices would allow much more surgeons to more widely adopt less invasive techniques. In summary, we see anastomotic devices as a solution to the technical challenges surgeons encounter with minimally invasive coronary artery bypass grafting.

Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger with Bypass Setpoint Temperature Control

NASA Technical Reports Server (NTRS)

Ungar, Eugene K.

2008-01-01

Spacecraft radiators are sized for their maximum heat load in their warmest thermal environment, but must operate at reduced heat loads and in colder environments. For systems where the radiator environment can be colder than the working fluid freezing temperature, radiator freezing becomes an issue. Radiator freezing has not been a major issue for the Space Shuttle and the International Space Station (ISS) active thermal control systems (ATCSs) because they operate in environments that are warm relative to the freezing point of their external coolants (Freon-21 and ammonia, respectively). For a vehicle that lands at the Lunar South Pole, the design thermal environment is 215K, but the radiator working fluid must also be kept from freezing during the 0 K sink of transit. A radiator bypass flow control design such as those used on the Space Shuttle and ISS requires more than 30% of the design heat load to avoid radiator freezing during transit - even with a very low freezing point working fluid. By changing the traditional ATCS architecture to include a regenerating heat exchanger inboard of the radiator and by using a regenerator bypass flow control valve to maintain system setpoint, the required minimum heat load can be reduced by more than half. This gives the spacecraft much more flexibility in design and operation. The present work describes the regenerator bypass ATCS setpoint control methodology. It includes analytical results comparing the performance of this system to the traditional radiator bypass system. Finally, a summary of the advantages of the regenerator bypass system are presented.

Gastric bypass surgeries in New Hampshire, 1996-2007.

PubMed

Cherala, Sai S

2012-01-01

Obesity is a national epidemic. Gastric bypass surgery may be the only option that provides significant long-term weight loss for people who are morbidly obese (body mass index [BMI] ≥ 40 kg/m²) or for people who have a BMI of 35 or higher and have an obesity-related comorbidity. The objective of this study was to assess trends in gastric bypass surgery in New Hampshire. Data from 1996 to 2007 from the New Hampshire Inpatient Hospital Discharge data set were analyzed. Records for patients with a gastric bypass surgery code were identified, and data on patients and hospitalizations were collected. A joinpoint regression model was used to analyze trends in surgery rates. Differences between patients and payer types were analyzed by using the Cochran-Mantel-Haenszel χ² test. The annual rate of gastric bypass surgery increased significantly from 3.3 to 22.4 per 100,000 adults between 1996 and 2007. The in-hospital death rate decreased significantly from 11% in 1996 to 1% in 2007. A greater proportion of women (78.1% during the study period) than men had this surgery. The average charge of a surgery decreased significantly from $44,484 in 1996 to $43,907 in 2007; by 2007, total annual charges were $13.9 million. Since 1996, private or "other" payers have been charged for nearly 80% of the total discharges. The number of gastric bypass surgeries has increased in New Hampshire, and so have their cost. These increases may reflect a shortage in effective primary care and preventive measures to address the obesity epidemic.

The relation between pro-oxidant antioxidant balance and glycolipid profile, 6 months after gastric bypass surgery.

PubMed

Banazadeh, Vahideh; Nematy, Mohsen; Ghayour Mobarhan, Majid; Tavallaie, Shima; Esmaily, Habibollah; Jangjoo, Ali

2018-03-01

Morbid obesity is a chronic disease that contributes to increased oxidative stress. Gastric bypass surgery is the gold standard method in treating co-morbidities. The objective of this study was to evaluate the relation between pro-oxidant antioxidant balance (PAB) as one measure of oxidative stress and glycolipid profile 6 months after gastric bypass surgery. Imam Reza Hospital, Mashhad University of Medical Sciences, Mashhad, Iran. Thirty-five morbidly obese patients with body mass index ≥35 kg/m 2 with co-morbidities or ≤40 kg/m 2 were randomly recruited. The PAB assay was used to estimate oxidative stress. Anthropometrics and glycolipid profile were collected at recruitment and 6 months after surgery. Statistical analysis was performed using SPSS 16 software. The study showed a significant postoperative reduction in serum PAB values compared with the baseline (P<.001). All anthropometric and several glycolipid parameters significantly reduced after surgery (P<.001), while serum high-density lipoprotein cholesterol was unaffected. Repeated measures analysis of variance showed that postoperative PAB values were affected by gastric bypass surgery (F = 12.51, P = .001). Regression analysis demonstrated medication usage controlling co-morbidities (β^ = -.6, P = .002) and fasting blood glucose (β^ = .41, P = .04) as independent factors in predicting PAB values 6 months after surgery. Gastric bypass surgery can reduce PAB values in favor of antioxidants 6 months after the operation. Accordingly, fasting blood glucose after gastric bypass surgery can be an independent factor in predicting PAB values. Copyright © 2018 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

Risk Factors of On-Pump Conversion during Off-Pump Coronary Artery Bypass Graft

PubMed Central

Yoon, Sung Sil; Bang, Jung Hee; Jeong, Sang Seok; Jeong, Jae Hwa; Woo, Jong Soo

2017-01-01

Background Off-pump coronary artery bypass grafting (OPCABG) procedures can avoid the complications of an on-pump bypass. However, some cases unexpectedly require conversion to cardiopulmonary bypass during OPCABG. The risk factors associated with a sudden need for cardiopulmonary bypass were analyzed. Methods This retrospective study included 283 subjects scheduled for OPCABG from 2001 to 2010. These were divided into an OPCABG group and an on-pump conversion group. Preoperative, operative, and postoperative variables were compared between the 2 groups. Results Of the 283 patients scheduled for OPCABG, 47 (16%) were switched to on-pump coronary artery bypass grafting (CABG). The mortality of the both the OPCABG and on-pump conversion groups was not significantly different. The major risk factors for conversion to on-pump CABG were congestive heart failure (CHF) (odds ratio [OR], 3.5; p=0.029), ejection fraction (EF) <35% (OR, 4.4; p=0.012), and preoperative beta-blocker (BB) administration (OR, 0.3; p=0.007). The use of intraoperative (p=0.007) and postoperative (p=0.021) inotropics was significantly higher in the conversion group. The amount of postoperative drainage (p<0.001) and transfusion (p<0.001) also was significantly higher in the conversion group. There were no significant differences in stroke or cardiovascular complications between the groups over the course of short-term and long-term follow-up. Conclusion Patients who undergo OPCABG and have CHF or a lower EF (<35%) are more likely to undergo on-pump conversion, while preoperative BB administration could help prevent conversions from OPCABG to on-pump CABG. PMID:29124027

Reconstituted fresh whole blood improves clinical outcomes compared with stored component blood therapy for neonates undergoing cardiopulmonary bypass for cardiac surgery: a randomized controlled trial.

PubMed

Gruenwald, Colleen E; McCrindle, Brian W; Crawford-Lean, Lynn; Holtby, Helen; Parshuram, Christopher; Massicotte, Patricia; Van Arsdell, Glen

2008-12-01

This study compared the effects of reconstituted fresh whole blood against standard blood component therapy in neonates undergoing cardiac surgery. Patients less than 1 month of age were randomized to receive either reconstituted fresh whole blood (n = 31) or standard blood component therapy (n = 33) to prime the bypass circuit and for transfusion during the 24 hours after cardiopulmonary bypass. Primary outcome was chest tube drainage; secondary outcomes included transfusion needs, inotrope score, ventilation time, and hospital length of stay. Patients who received reconstituted fresh whole blood had significantly less postoperative chest tube volume loss per kilogram of body weight (7.7 mL/kg vs 11.8 mL/kg; P = .03). Standard blood component therapy was associated with higher inotropic score (6.6 vs 3.3; P = .002), longer ventilation times (164 hours vs 119 hours; P = .04), as well as longer hospital stays (18 days vs 12 days; P = .006) than patients receiving reconstituted fresh whole blood. Of the different factors associated with the use of reconstituted fresh whole blood, lower platelet counts at 10 minutes and at the end of cardiopulmonary bypass, older age of cells used in the prime and throughout bypass, and exposures to higher number of allogeneic donors were found to be independent predictors of poor clinical outcomes. Reconstituted fresh whole blood used for the prime, throughout cardiopulmonary bypass, and for all transfusion requirements within the first 24 hours postoperatively results in reduced chest tube volume loss and improved clinical outcomes in neonatal patients undergoing cardiac surgery.

Systematic off-pump coronary artery revascularization in multivessel disease: experience of three hundred cases.

PubMed

Cartier, R; Brann, S; Dagenais, F; Martineau, R; Couturier, A

2000-02-01

We sought to report our recent experience with off-pump coronary artery revascularization in multivessel disease. Between October 1996 and December 1998, 300 off-pump beating heart operations were performed at the Montreal Heart Institute by a single surgeon, representing 94% of all procedures undertaken during this same time frame (97% for 1998). This cohort of patients was compared with 1870 patients operated on with cardiopulmonary bypass from 1995 to 1996. Mean age, sex distribution, and preoperative risk factors were comparable for the two groups. On average, 2.92 +/- 0.8 and 2.84 +/- 0.6 grafts per patient were completed in the beating heart and cardiopulmonary bypass groups, respectively. A majority of patients (70%) had either a triple or quadruple bypass. Coronary anastomoses were achieved with myocardial mechanical stabilization and heart "verticalization." Ischemic time was shorter in the beating heart group (29.8 +/- 0.9 vs 45 +/- 0.4 minutes, P <.05). Similarly, the need for transfusion was significantly less in the beating heart group (beating heart operations, 34%; cardiopulmonary bypass, 66%; P <.005). Reduced use of postoperative intra-aortic counterpulsation, as well as a lower rise in creatine kinase MB isoenzyme, was observed in the beating heart group. Operative mortality rates (beating heart operations, 1. 3%; cardiopulmonary bypass, 2%) and perioperative myocardial infarction (beating heart operations, 3.6%; cardiopulmonary bypass, 4.2%) were comparable for the two groups. In a majority of patients, off-pump complete coronary artery revascularization is an acceptable alternative to conventional operations, yielding good results given progressive experience, rigorous technique, and adequate coronary artery stabilization.

Effects of preoperative aspirin and clopidogrel therapy on perioperative blood loss and blood transfusion requirements in patients undergoing off-pump coronary artery bypass graft surgery.

PubMed

Shim, Jae Kwang; Choi, Yong Seon; Oh, Young Jun; Bang, Sou Ouk; Yoo, Kyung Jong; Kwak, Young Lan

2007-07-01

Preoperative exposure to clopidogrel and aspirin significantly increases postoperative bleeding in patients undergoing on-pump coronary artery bypass graft surgery. Off-pump coronary bypass grafting has been proposed as an alternative technique to attenuate postoperative bleeding associated with clopidogrel. This study aimed to determine the effects of aspirin and clopidogrel therapy on perioperative blood loss and blood transfusion requirements in off-pump coronary artery bypass grafting. One hundred six patients scheduled for off-pump coronary artery bypass grafting were divided into three groups: aspirin and clopidogrel discontinued more than 6 days before surgery (group 1, n = 35), aspirin and clopidogrel continued until 3 to 5 days before surgery (group 2, n = 51), and both medications continued within 2 days of surgery (group 3, n = 20). Thromboelastographic tracings were analyzed before induction of anesthesia. Routine coagulation profiles were measured before and after surgery. A cell salvage device was used during surgery and salvaged blood was reinfused. Chest tube drainage and blood transfusion requirement were recorded postoperatively. Patient characteristics, operative data, and thromboelastographic tracings were similar among the groups. There were significant decreases in hematocrit level and platelet count and prolongation in prothrombin time postoperatively in all groups without any intergroup differences. The amounts of perioperative blood loss and blood transfusion required were all similar among the groups. Preoperative clopidogrel and aspirin exposure even within 2 days of surgery does not increase perioperative blood loss and blood transfusion requirements in patients undergoing elective off-pump coronary artery bypass grafting.

Ultrafiltration and modified ultrafiltration in pediatric open heart operations.

PubMed

Elliott, M J

1993-12-01

The capillary leak associated with cardiopulmonary bypass results in an increase in content of water in the tissues measurable by an increase in total body water after cardiac operation. Following work by Magilligan in the 1970s, ultrafiltration was introduced during bypass as a means of hemoconcentrating patients and potentially removing water from the tissues. Conventional methods proved inconsistent; thus, we modified the technique to ultrafilter the patients immediately after cessation of bypass. Modified ultrafiltration takes 10 minutes and results in an elevation of the on-bypass hematocrit to about 35% or 40%. In pilot studies comparing bypass in absence of ultrafiltration with conventional ultrafiltration and modified ultrafiltration, only the modified technique was seen reliably to reduce the elevation in total body water to only 4%, within a narrow range. Subsequent prospective studies confirmed the reduction in accumulation of total body water and also demonstrated a reduction in blood loss and in requirements for blood transfusion. Systolic blood pressure was observed to increase uniformly in all patients undergoing modified ultrafiltration. This effect was investigated and found to be associated with a marked increase in cardiac index, no change in systemic vascular resistance, a decrease in heart rate, and a marked decrease in pulmonary vascular resistance. Recently, we have demonstrated an increase in contractility and a decrease in myocardial wall volume. The modified technique of ultrafiltration has been employed successfully in more than 400 patients in our institution, and represents an excellent option for perioperative management of both accumulation of fluid in the tissues and hemodynamics after hypothermic bypass.

Hybrid coronary revascularization in the era of drug-eluting stents.

PubMed

Murphy, Gavin J; Bryan, Alan J; Angelini, Gianni D

2004-11-01

Left internal mammary artery to left anterior descending coronary artery bypass grafting integrated with percutaneous coronary angioplasty (hybrid procedure) offers multivessel revascularization with minimal morbidity in high-risk patients. This is caused in part by the avoidance of cardiopulmonary bypass-related morbidity and manipulation of the aorta coupled with minimally invasive techniques. Hybrid revascularization is currently reserved for particularly high-risk patients or those with favorable anatomic variants however, largely because of the emergence of off-pump coronary artery bypass grafting, which permits more complete multivessel revascularization, with low morbidity in high-risk groups. The wider introduction of hybrid revascularization is limited chiefly by the high number of repeat interventions compared with off-pump coronary artery bypass grafting, which occurs because of the target vessel failure rate of percutaneous coronary intervention. Other demerits are the costs and logistic problems associated with performing two procedures with differing periprocedural management protocols. Recently, drug-eluting stents have reduced the need for repeat intervention after percutaneous coronary intervention, and this has raised the possibility that the results of hybrid revascularization may now equal or even better those of off-pump coronary artery bypass grafting. Although undoubtedly effective at reducing in-stent restenosis, drug-eluting stents will not address the issues of incomplete revascularization or the logistic problems associated with hybrid. Uncertainty regarding the long-term effectiveness of drug-eluting stents in many patients, as well as their high cost when compared with those of off-pump coronary artery bypass grafting surgery, also militates against the wider introduction of hybrid revascularization.

Temperature monitoring during cardiopulmonary bypass--do we undercool or overheat the brain?

PubMed

Kaukuntla, Hemanth; Harrington, Deborah; Bilkoo, Inderaj; Clutton-Brock, Tom; Jones, Timothy; Bonser, Robert S

2004-09-01

Brain cooling is an essential component of aortic surgery requiring circulatory arrest and inadequate cooling may lead to brain injury. Similarly, brain hyperthermia during the rewarming phase of cardiopulmonary bypass may also lead to neurological injury. Conventional temperature monitoring sites may not reflect the core brain temperature (Tdegrees). We compared jugular bulb venous temperatures (JB) during deep hypothermic circulatory arrest and normothermic bypass with Nasopharyngeal (NP), Arterial inflow (AI), Oesophageal (O), Venous return (VR), Bladder (B) and Orbital skin (OS) temperatures. 18 patients undergoing deep hypothermia (DH) and 8 patients undergoing normothermic bypass (mean bladder Tdegrees-36.29 degreesC) were studied. For DH, cooling was continued to 15 degreesC NP (mean cooling time-66 min). At pre-determined arterial inflow Tdegrees, NP, JB and O Tdegree's were measured. A 6-channel recorder continuously recorded all Tdegree's using calibrated thermocouples. During the cooling phase of DH, NP lagged behind AI and JB Tdegree's. All these equilibrated at 15 degreesC. During rewarming, JB and NP lagged behind AI and JB was higher than NP at any time point. During normothermic bypass, although NP was reflective of the AI and JB Tdegrees trends, it underestimated peak JB Tdegrees (P=0.001). Towards the end of bypass, peak JB was greater than the arterial inflow Tdegrees (P=0.023). If brain venous outflow Tdegrees (JB) accurately reflects brain Tdegrees, NP Tdegrees is a safe surrogate indicator of cooling. During rewarming, all peripheral sites underestimate brain temperature and caution is required to avoid hyperthermic arterial inflow, which may inadvertently, result in brain hyperthermia.