Abstract 77: Predictive Power of Early Lactate Clearance Regarding 30-Day Neurological Outcome After Cardiac Arrest with Cardiopulmonary Bypass

Abstract

Objective: Early lactate clearance has been reported to be associated with improved mortality in patients with post cardiac arrest syndrome (PCAS). Recently, cardiopulmonary bypass (CPB) has significantly improved prognosis of those patients, however, it has been still unknown whether early lactate clearance could predict for neurological outcome in PCAS with CPB. We aimed to investigate the usefulness of the early lactate clearance in a cardiac arrest of patients resuscitated and treated with CPB. Methods: Retrospective observational study. Between January 2000 and March 2011, 46 cardiac arrest patients with cardiac causes underwent CPB in a university hospital in Tokyo. Of those, serial arterial lactate concentrations (at ICU admission and 6 hours after ICU admission) were obtained from 21 patients (19 Males, median 61 y/o). Lactate clearance was defined as the percent change after 6 hours from baseline. The patients were divided into two groups (high lactate clearance group or low lactate clearance) by median lactate clearance. Results: The lactate clearance in the high lactate clearance group was 50.3±13.1% (mean±SD) and the low lactate clearance group -14.7±23.9%. There were no significant differences between the groups for demographics, laboratories (except platelets, baseline PaO 2 ), baseline lactate (the high lactate clearance group: 11.3±3.5mg/dl, the low lactate clearance group:10.8±4.2mg/dl), baseline arterial pressure (99.9±41.1mmHg, 96.1±26.7mmHg), use of catecholamine. In the high clearance group, there was significantly higher for favorable CPC (<=2) rate (44% vs 0%, OR 2.8, 95%CI [1.48-5.40]) and Kaplan-Meier survival analysis showed a survival benefit over 30 days (log-rank; p=0.02). Cut-off points with 95% specificity in predicting favorable outcome was 67.4% for early lactate clearance (sensitivity 75%). CONCLUSIONS: Early lactate clearance is specific but only moderately sensitive markers of 30-day neurological outcome. These findings suggest that post arrest tissue hypoperfusion during CPB contributes lactate clearance, regardless CPB.