Postoperative Cerebral and Somatic Near-Infrared Spectroscopy Saturations and Outcome in Hypoplastic Left Heart Syndrome

Abstract

Circulatory vulnerability reflected by low systemic venous oxygen saturation after surgical palliation of hypoplastic left heart syndrome predicts adverse neurologic outcome and reduced survival, and targeting venous saturation may improve outcome. We herein test the hypothesis that near-infrared spectroscopy (NIRS)-derived cerebral and somatic/renal regional saturations can predict survival. Patient data, from a prospective Institutional Review Board-approved registry of hemodynamic measures after initial palliation of hypoplastic left heart syndrome, were analyzed with logistic and multivariable mixed regression methods to determine relationships between standard hemodynamic measures, direct and NIRS measures of saturation, and outcome. The primary outcome measure was survival through hospital discharge and 30 days. From the entire cohort of 329 patients, complete data for comparative analysis of physiologic predictors were available from 194 patients. The early survival rate was 92.1%; extracorporeal membrane oxygenation was used in 8.8% of patients. The mean arterial pressure, arterial cerebral, and somatic cerebral NIRS saturation differences were significantly higher for survivors versus nonsurvivors. Multivariable analysis found cerebral and somatic NIRS saturations, heart rate, and arterial pressure as predictors of outcome. Bivariate analysis of mean arterial pressure and somatic saturation allowed early identification of low cardiac output and high mortality risk. Continuous noninvasive measurement of regional cerebral and somatic NIRS saturations in the early postoperative period can predict outcomes of early mortality and extracorporeal membrane oxygenation use in hypoplastic left heart syndrome. Because outcomes were strongly determined by NIRS measures at 6 hours, early postoperative NIRS measures may be rational targets for goal-directed interventions.