Near-Infrared Spectroscopy in Adult Cardiac Surgery Patients: A Systematic Review and Meta-Analysis.

OBJECTIVES

To identify the normal baseline preoperative range of cerebral tissue oxygen saturation (SctO) derived using near-infrared spectroscopy (NIRS) and the efficacy of perioperative interventions designed to modulate SctO 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) SctO 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 SctO using NIRS. The pooled mean baseline SctO 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 SctO across the majority of reported time points. Postoperative follow-up of SctO occurred in only 1 study, and postoperative cognitive assessment correlating SctO with cognitive function was applied in only 4 studies using variable methodology.

CONCLUSIONS

The authors have established that reference values for baseline NIRS-derived SctO in cardiac surgery patients are varied and have identified interventions that modulate SctO. This information opens the door to standardized research and interventional studies in this field.