Cerebral Perfusion During Cardiopulmonary Bypass in Children: Correlations Between Near-Infrared Spectroscopy, Temperature, Lactate, Pump Flow, and Blood Pressure

Near-infrared spectroscopy (NIRS) is a noninvasive modality to monitor regional brain oxygenation (rSO2). In this study, we aimed to investigate the correlation between cerebral rSO2 and lactate, pump flow, hematocrit, pCO2, and mean blood pressure (MBP) during cardiopulmonary bypass (CPB). Between March and September 2011, 50 pediatric patients who underwent congenital heart surgery were enrolled into the study. Ages ranged from 6 days to 168 months (median 14 months). A NIRS sensor (Somanetics 5100B, Troy, MI, USA) was placed on the right forehead of patients. CPB period was divided into five stages: 1at the beginning of CBP, 2cooling at 32 degrees C, 3at final hypothermic temperature, 4rewarming at 32 degrees C, 5before weaning from CPB. Data collection included measurements of each parameter at five stages of CPB. Data were analyzed using multivariate analysis within groups and Spearman's correlation to test association between parameters. Lactate levels increased significantly from stage 1 to stage 5 during CPB (P<0.05). There was no significant correlation between cerebral rSO2 and MBPs, pump flows, hematocrit, or pCO2 during CPB. Cerebral rSO2 levels showed changes between the stages; there was a significant increase during cooling period, compared to stage 1 (P