The Journal of extra-corporeal technology
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J Extra Corpor Technol · Mar 2014
Comparative StudyComparison of routine laboratory measures of heparin anticoagulation for neonates on extracorporeal membrane oxygenation.
Our objective was to determine the best measure of heparin anticoagulation in neonatal patients on extracorporeal membrane oxygenation. Activated clotting time (ACT), activated partial thromboplastin time (aPTT), and antifactor Xa levels, along with corresponding heparin infusion rates and heparin bolus volumes, were collected from neonates receiving ECMO at our institution from 2008 to 2013. After natural log transformation of antifactor Xa, ACT, and aPTT, overall correlations between antifactor Xa levels and either ACT or aPTT and correlations between these tests and heparin infusion rates were evaluated using linear mixed models that accounted for both within- and between-patient correlations. ⋯ In contrast, between patients, only aPTT maintained a direct correlation with antifactor Xa (r = .61, p = .07), whereas ACT showed a statistically significant inverse correlation with antifactor Xa (r = -.48, p = .04). Compared with ACT, aPTT is more consistently reflective of the anticoagulation status both within each patient on ECMO and between patients treated with ECMO. Future efforts to develop standardized heparin infusion algorithms for patients on ECMO should consider using aPTT levels to monitor anticoagulation.
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Cognitive deterioration can reliably be measured after procedures requiring anesthesia and surgery. Cardiac surgery has had the spotlight because of the high reported incidence of postoperative cognitive dysfunction in early studies, but such effects occur after other surgical procedures as well. "Early" postoperative cognitive dysfunction should be considered as a different phenomenon, relating to acute pharmacological, physiological, and stress-related recovery. The focus should be on what is affecting patients at 3 months, 12 months, and 5 years later. ⋯ The blood-brain barrier is made vulnerable by both pre-existing disorders (mild cognitive impairment/amyloid; vascular disease) and by the inflammatory response to surgery and cardiopulmonary bypass. Inflammation affecting the brain at this time may set in motion accelerated neurological and hence cognitive decline that, despite an initial recovery and even functional improvement, may proceed to further long-term decline at an accelerated rate in susceptible individuals. Clinical data are emerging from longer-term studies to support this concern, but evidence for effective preventive or therapeutic strategies is limited.
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The use of intravenous fluids is routine in patients undergoing surgery or critical illness; however, controversy still exists regarding optimum fluid therapy. Recent literature has examined the effects of different types, doses, and timing of intravenous fluid therapy. Each of these factors may influence patient outcomes. ⋯ Crystalloid solutions with a chloride-rich composition (e.g., isotonic saline) have been associated with metabolic acidosis, hyperchloremia, increased incidence of acute kidney injury, and increased requirement for renal replacement therapy. An optimum dose of intravenous fluids remains controversial with no definitive evidence to support restrictive versus liberal approaches. Further high-quality trials are needed to elucidate the optimum fluid therapy for patients, but currently a balanced approach to type, dose, and timing of fluids is recommended.
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J Extra Corpor Technol · Mar 2014
Case ReportsBivalirudin in venovenous extracorporeal membrane oxygenation.
Optimal anticoagulation plays a pivotal role in successful outcome of extracorporeal membrane oxygenation (ECMO). Heparin has been the anticoagulant of choice owing to its advantages like easy monitoring and reversibility. However, if heparin resistance is encountered, one has to decide whether to treat heparin resistance with fresh-frozen plasma or antithrombin concentrates or to choose one of the heparin alternatives for anticoagulation. ⋯ We found a bivalirudin dose of .1-.2 mg/kg/h to be adequate to maintain a target activated clotting time of 200-220 seconds. Platelet counts were stable throughout and no major bleeding or thrombotic complications took place. We found bivalirudin to be a feasible and effective anticoagulant and safe to use for long durations in ECMO without any major complications.
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J Extra Corpor Technol · Mar 2014
Comparative StudyCan the oxygenator screen filter reduce gaseous microemboli?
Gaseous microemboli (GME) define small bubbles as < 200 microm in size. GME are reported to increase morbidity after cardiopulmonary bypass (CPB) and cardiac surgery. To prevent intrusion of GME into the systemic circulation during CPB, arterial line filtration is generally recommended. ⋯ At 6 L/min, the reduction was 97.9% +/- .1% compared with 97.0% +/- .1% (p < .001). In contrast, the reduction of GME counts was less effective after screen filtration compared with controls: 89.6 +/- .6% versus 91.4 +/- .4% at 4 L/min and 55.6% +/- 1.6% versus 76.0% +/- 1.4% at 6 L/min, respectively (p < .001). The tested oxygenator with incorporated arterial screen filter reduced GME activity based on the calculated volume at the same time as counts of GME increased.