The Journal of extra-corporeal technology
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Clinical use of extracorporeal membrane oxygenation (ECMO) and carbon dioxide removal (ECCO 2R) have become well established techniques for the treatment of severe respiratory failure; however they require full cardiopulmonary bypass, representing major procedures with high morbidity. We theorized the possibility of an efficient low flow veno-venous extracorporeal membrane gas exchange method. Four mongrel 12 kg dogs were submitted to veno-venous extracorporeal membrane gas exchange via a jugular dialysis catheter using a low flow (10 ml/min) roller pump and a membrane oxygenator for a period of four hours. ⋯ Adequate gas exchange was obtained (pO 2139, pCO 224, Sat 99.4%), without major hemodynamic changes or hematuria. Our results demonstrate the feasibility of a low flow, less aggressive system. Further research should be considered.
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J Extra Corpor Technol · Jan 1993
Randomized Controlled Trial Clinical TrialSafety of heparin-coated circuits in primates during deep hypothermic cardiopulmonary bypass.
The purpose of this study is to evaluate the biologic impact of heparin-coated circuits without systemic heparinization during deep hypothermia. Baboons (n=6) were placed on a heparin-coated pediatric closed-circuit cardiopulmonary bypass (CPB) system and cooled to 18 degrees C. A control group (n=7) underwent similar protocol with a non heparin-coated circuit and received systemic heparin. Either low flow at 0.5 L/min/m 2 (n=8; 4 in each group) or circulatory arrest (n=5; 2 in experimental group and 3 in control group) was used during deep hypothermia. Samples for complete blood count (CBC), hepatic and renal function tests, activated clotting time (ACT) and thrombelastogram (TEG) were obtained before, during, and after bypass. Cerebral blood flow was measured using Xenon-133 and autopsies were performed to assess end-organ damage. The ACT returned to baseline in both groups, and renal and hepatic function were within normal limits. There was no significant difference between the TEG values between the groups post bypass. Fibrin split products were absent and fibrinogen levels were normal in both groups following bypass. Cerebral blood flows were equivalent in both groups before and after bypass, although in the heparin-coated group cerebral blood flows were significantly higher during CPB. There were no brain histologic changes in the heparin-coated group and one focal cortical infarct in the control group. This study suggests that hypothermia induced a state of anticoagulation that did not result in thrombus formation or end organ dysfunction during CPB with a heparin-coated circuit.(ABSTRACT TRUNCATED AT 250 WORDS)
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J Extra Corpor Technol · Jan 1993
Comparative StudyClinical comparisons of continuous venous oxygen saturation and hematocrit monitors in pediatric surgery.
Continuous venous oxygen saturation and hematocrit values are important parameters in assessing patient status while on cardiopulmonary bypass. Two devices used to measure continuous venous oxygen saturation while on cardiopulmonary bypass were compared to a control. The Bentley Oxysat meter and the Medtronic MX2 Oxygen Saturation and Hematocrit System were compared to the ABL500 blood gas monitor. ⋯ The correlation between the MX2 device and the spun hematocrit varied with temperature ranges. The correlation coefficient tended to decrease with decreasing temperature. We conclude that these devices are important adjuncts to bypass as long as their limitations are understood.
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J Extra Corpor Technol · Jan 1993
Trouble shooting the extracorporeal membrane oxygenator circuit and patient.
Patients requiring extracorporeal membrane oxygenation (ECMO) often become totally dependent on the mechanical life support. The Extracorporeal Life Support Organization (ELSO) reports 2486 incidents of mechanical complications in 5905 ECMO supports. To help decrease the number of mechanical complications, an active quality assurance program was initiated at our institution. ⋯ Techniques for dealing with problems such as loss of roller pump occlusion, changing out of the membrane lung or heat exchanger without interrupting ECMO support, venous air lock, tamponade, emergency transfusion, and other situations were generated into written policies and procedures. We routinely review and practice problem solving techniques with specific emphasis on monitoring patient hemodynamics and appearance. We conclude that written policies and procedures, "water drills," and continuing education can be beneficial in early recognition, intervention, and/or prevention of ECMO mechanical complications.
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Rewarming, a key event in resuscitation from accidental, experimental and clinical hypothermia, is sometimes followed by neurologic, cardiac, and respiratory sequelae and may lead to death. The rate of rewarming has been implicated but not quantified as etiologic in these sequelae. Under anesthesia fifteen dogs were cannulated and connected to an extracorporeal circuit for oxygenation, core cooling and rewarming. ⋯ Normal body temperature for a dog is 37.8 degrees C. Statistical analysis (ANOVA) was performed ex post facto to determine the relationship between rewarming rate and outcome. Our data contradicts the notion that slow core rewarming from nadir to normal temperature offers better outcome.(ABSTRACT TRUNCATED AT 250 WORDS)