The effect of near-infrared spectroscopy guided intraoperative care on neurocognitive and functional outcomes after cardiac surgery: a systematic review and meta-analysis of randomised controlled trials

Background: Adverse neurocognitive and functional outcomes are common after cardiac surgery. Cerebral near-infrared spectroscopy (NIRS) monitors regional cerebral oxygen saturation, allowing clinicians to detect and reverse cerebral desaturation. We conducted a systematic review and meta-analysis of RCTs to evaluate whether intraoperative NIRS monitoring improves neurocognitive outcomes after cardiac surgery. Methods: We searched CENTRAL, CINAHL, Embase, MEDLINE, PsycINFO, and Web of Science for RCTs comparing NIRS-guided intraoperative management with usual care in adults undergoing on-pump cardiac surgery, assessing the outcomes of postoperative cognitive decline, delirium, stroke, mortality, and functional recovery. We pooled data using random-effects meta-analysis and assessed certainty of evidence using GRADE methodology. Results: We included 17 RCTs (N=2288). NIRS-guided management probably reduces early postoperative cognitive decline (risk ratio [RR] 0.65, 95% CI 0.42–0.99; I2=65%, moderate certainty), may have little or no effect on stroke (RR 0.89, 95% CI 0.42–1.91; low certainty) or mortality (RR 0.84, 95% CI 0.47–1.52; low certainty), and may have no effect on delirium (RR 0.78, 95% CI 0.56–1.09; I2=32%, low certainty). Findings were primarily derived from small, single-centre trials with heterogenous NIRS thresholds and intervention algorithms. Few studies evaluated outcomes beyond 30 days, and none evaluated validated measures of quality of life or function. Conclusions: Although NIRS-guided intraoperative care shows promise for reducing early postoperative cognitive decline after cardiac surgery, evidence of benefit for other neurocognitive or clinical outcomes remains limited. Large multicentre studies are needed to confirm its utility, refine intervention thresholds, and determine its impact on long-term cognition, function, and quality of life.Systematic review protocol. PROSPERO (CRD42022336468).