NIRS-guided care probably reduces early cognitive decline after cardiac surgery, but little else is shown

Design

Systematic review and meta-analysis of randomised trials, GRADE certainty rated

Population

17 trials, 2,288 adults having on-pump cardiac surgery

Primary outcome

Postoperative cognitive decline, delirium, stroke, mortality and functional recovery

Effect

Early cognitive decline RR 0.65 (95% CI 0.42 to 0.99); stroke RR 0.89; mortality RR 0.84; delirium RR 0.78

Cerebral near-infrared spectroscopy measures regional cerebral oxygen saturation so desaturation can be detected and treated. This systematic review pooled 17 randomised trials with 2,288 adults having on-pump cardiac surgery, comparing NIRS-guided management with usual care.

NIRS-guided care probably reduced early postoperative cognitive decline (RR 0.65, 95% CI 0.42 to 0.99; I-squared 65%; moderate certainty). Effects on stroke (RR 0.89, 0.42 to 1.91), mortality (RR 0.84, 0.47 to 1.52) and delirium (RR 0.78, 0.56 to 1.09) were uncertain, all with low certainty.

The included trials were mostly small and single-centre, used different NIRS thresholds and intervention algorithms, rarely followed patients beyond 30 days, and none measured validated quality of life or function. The signal for early cognitive decline is encouraging, but its interval barely excludes no effect and the clinical meaning of early decline is unclear. If NIRS is already available, guided care is reasonable; the review does not establish a standard algorithm.

• Early cognitive decline was reduced (RR 0.65, 95% CI 0.42 to 0.99), with moderate certainty.
• Stroke, mortality and delirium effects were uncertain.
• Intervention thresholds and algorithms varied across trials.
• Few trials followed patients beyond 30 days or measured function.
• If you use NIRS, define the desaturation threshold and the response steps in advance.

Why it matters

It gives a modest evidence base for a monitor many theatres already own.

Don't overread it

The effect is on early cognitive decline only; the review does not show fewer strokes, deaths or better function.

The statistics, in plain English

A risk ratio of 0.65 with an interval of 0.42 to 0.99 means about a third fewer cases of early decline, but the upper end sits just below 1, so the result is fragile. An I-squared of 65% shows considerable disagreement between trials, partly because they used different thresholds.

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