Prospective randomized trial of normothermic versus hypothermic cardiopulmonary bypass on cognitive function after coronary artery bypass graft surgery.

BACKGROUND: Despite significant advances in cardiopulmonary bypass (CPB) technology, surgical techniques, and anesthetic management, central nervous system complications occur in a large percentage of patients undergoing surgery requiring CPB. Many centers are switching to normothermic CPB because of shorter CPB and operating room times and improved myocardial protection. The authors hypothesized that, compared with normothermia, hypothermic CPB would result in superior neurologic and neurocognitive function after coronary artery bypass graft surgery. METHODS: Three hundred patients undergoing elective coronary artery bypass graft surgery were prospectively enrolled and randomly assigned to either normothermic (35.5-36.5 degrees C) or hypothermic (28-30 degrees C) CPB. A battery of neurocognitive tests was performed preoperatively and at 6 weeks after surgery. Four distinct cognitive domains were identified and standardized using factor analysis and were then compared on a continuous scale. RESULTS: Two hundred twenty-seven patients participated in 6-week follow-up testing. There were no differences in neurologic or neurocognitive outcomes between normothermic and hypothermic groups in multivariable models, adjusting for covariable effects of baseline cognitive function, age, and years of education, as well as interaction of these with temperature treatment. CONCLUSIONS: Hypothermic CPB does not provide additional central nervous system protection in adult cardiac surgical patients who were maintained at either 30 or 35 degrees C during CPB.

Laudanosine and atracurium concentrations in a patient receiving long-term atracurium infusion.

OBJECTIVE: Atracurium is sometimes used for muscle relaxation in patients undergoing mechanical ventilation. Use of atracurium in high doses or for a long period of time has raised the possibility of the accumulation of laudanosine, a breakdown product known to cause seizure activity in animals. The objective of this report was to see if laudanosine accumulation and seizure activity had occurred in a patient who had received a long-term, relatively high-dose infusion of atracurium. DESIGN: Case report. The patient received atracurium for 38 days, at rates ranging from 0.3 to 0.96 mg/kg/hr. An electroencephalogram (EEG) was done before the discontinuation of the infusion, and plasma concentrations of atracurium and laudanosine were measured at, and after, the termination of the atracurium infusion. The laudanosine elimination half-life was calculated. SETTING: Intensive care unit. PATIENT: A 23-yr-old woman admitted with sickle cell crisis, complicated by acute chest syndrome, acute respiratory distress syndrome, and hepatic and renal failure. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: As expected, laudanosine concentrations were increased but were below the level reported to cause seizure activity in animals. Laudanosine elimination half-life was prolonged to 617 mins, which was consistent with previously reported values. The patient's EEG was normal, with no ictal pattern. CONCLUSIONS: Despite long-term use of high doses of atracurium infusion and the increased elimination half-life of laudanosine, only moderate accumulation of laudanosine occurred, and the EEG was normal. Hence, it appears unlikely that toxic concentrations of laudanosine would be reached, even in a critically ill patient.