Perfusion
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To evaluate the use of extracorporeal membrane oxygenation (ECMO) in patients with Gram-negative or viral sepsis, a survey of ECMO centres comprising the Extracorporeal Life Support Organization was conducted. Data collected from neonatal and paediatric intensive care units included patient demographics, indicators of infection, presence of cardiac instability and respiratory criteria for ECMO. One-hundred-and-seven patients with documented sepsis were divided into survivors and nonsurvivors. ⋯ Although survival is less in septic infants than in infants with traditional respiratory failure placed on ECMO, sepsis should not be a contraindication to the use of ECMO. The parents should be informed of the chances of survival with each type of sepsis or respiratory infection (if known), so that a truly informed decision can be made by the parents. We feel that the additional information regarding Gram-negative and viral sepsis should assist the clinician in this goal.
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Some clinicians place patients in the Trendelenburg position during aortic unclamping to decrease the incidence of microscopic cerebral air embolism. Experimental studies have shown that use of the Trendelenburg position does not prevent air emboli from reaching the brain. Nevertheless, the position can decrease the velocity at which bubbles approach the brain, giving more time for nitrogen in the bubbles to be absorbed. ⋯ The result holds for all usual conditions of CPB. We conclude that absorption does not affect the disposition of air introduced into the arterial circulation. Use of the Trendelenburg position cannot decrease neurologic injury from cerebral air embolism by permitting greater bubble absorption.
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To ascertain current anticoagulation management during neonatal extracorporeal membrane oxygenation (ECMO), a telephone survey was undertaken of all active ECMO (n = 81, 100% response rate) centres in the USA. Hospital policies regarding federal regulations governing laboratory tests [Clinical Laboratory Improvement Amendment (CLIA) 1988] were determined along with specific patient anticoagulation strategies and use of specific activated coagulation time (ACT) equipment. More than 90% of the respondents use the Hemochron device (International Technidyne Corp, Edison, NJ, USA) while the remaining centres use the Hemotec device (Medtronic Hemotec, Inc, Englewood, CO, USA). ⋯ Four out of five respondents reported that heparin dosages were dictated strictly by ACT results, and 63% will temporarily stop heparin administration for high ACT results, bleeding and/or surgery. Approximately one-third of the centres perform proficiency testing of the equipment in compliance with CLIA 1988. In conclusion, there appears to be no consensus regarding commitment to a QC programme among active ECMO centres.
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Data relating to the activated clotting time response to a 4 mg/kg heparin loading dose were collected prospectively in 358 patients having cardiopulmonary bypass. After excluding patients with factors known to cause relative heparin resistance or sensitivity, the activated clotting time (ACT) loading dose response ratio (ACTLORR) was calculated retrospectively in 263 patients and found to correlate significantly (p = 0.0001) with the need for extra heparin administration during bypass. ⋯ Where the ACTLORR was between 4.0 and 5.0, it was far less predictive, with approximately 35% of patients requiring additional heparin. This study indicates that a large ACT response to the initial heparin loading dose (a high ACTLORR) is predictive of stable, adequate anticoagulation during the first 90 minutes of bypass, but that a low initial response is not necessarily associated with declining ACTs and the need for additional heparin administration.