Near-infrared spectroscopy in adult cardiac surgery patients: a systematic review and meta-analysis

Abstract

OBJECTIVES: To identify the normal baseline preoperative range of cerebral tissue oxygen saturation (SctO2) derived using near-infrared spectroscopy (NIRS) and the efficacy of perioperative interventions designed to modulate SctO2 in cardiac surgical patients. DESIGN: Systematic review and meta-analysis of relevant randomized controlled trials (RCTs) extracted from the Medline, Embase, and Cochrane Central Register of Controlled Trials databases. SETTING: Hospitals performing cardiac surgery. PARTICIPANTS: The study comprised 953 participants from 11 RCTs. INTERVENTIONS: Interventions included the following: (1) SctO2 monitoring protocol compared with no monitoring; (2) use of cardiopulmonary bypass (CPB) compared with no CPB; (3) normothermic CPB compared with hypothermic CPB; (4) glyceryl trinitrate during surgery compared with placebo; (5) midazolam during induction of anesthesia compared with propofol; (6) sevoflurane anesthesia compared with total intravenous anesthesia; (7) sevoflurane anesthesia compared with propofol-based anesthesia; and (8) norepinephrine during CPB compared with phenylephrine. MEASUREMENTS AND MAIN RESULTS: Eleven RCTs with 953 participants measured baseline preoperative SctO2 using NIRS. The pooled mean baseline SctO2 was 66.4% (95% CI 65.0-67.7), generating a reference range of 51.0% to 81.8%. Four interventions (1, 3, 4, and 6 described in the Interventions section above) increased intraoperative SctO2 across the majority of reported time points. Postoperative follow-up of SctO2 occurred in only 1 study, and postoperative cognitive assessment correlating SctO2 with cognitive function was applied in only 4 studies using variable methodology. CONCLUSIONS: The authors have established that reference values for baseline NIRS-derived SctO2 in cardiac surgery patients are varied and have identified interventions that modulate SctO2. This information opens the door to standardized research and interventional studies in this field.