Article description

Summary:

• To examine the association/effect of intraoperative cerebral oximetry (CeOx) on major organ morbidity and mortality (MOMM) after adult cardiac surgery.
• Retrospective, multicenter cohort study.
• Patients >18 years old from the Society of Thoracic Surgeons Adult Cardiac Surgery Database treated between July 1, 2011 and December 31, 2016, for isolated coronary artery bypass graft (CABG) or valve repair or replacement, or any combination of procedures with cardiopulmonary bypass at any participating Institution, who received intraoperative CeOx monitoring, and with a 30-day postoperative follow-up were included.
• MOMM included operative mortality (in-hospital or within 30 days from surgery), stroke, renal failure (creatinine > 2.0 mg/dL or >2x preoperative value), prolonged mechanical ventilation (> 24h postoperatively), deep sternal wound infection, or reoperation-for-any-reason-within-30-days.
• In the study period, 1.19 million patients within 1,180 Institutions met the inclusion criteria.
• 30% (n = 361,124) received CeOx versus nonrecipients (n = 838,675) with similar baseline patient characteristics. Using a propensity score-based 1:1 greedy matching method, 99.7% of CeOx recipients (n = 360,285) were matched with nonrecipients.
• The rates of MOMM were lower with versus without CeOx, with a number needed to treat (NNT) of 227 patients (95% CI: 166-363, p < 0.0001).
• The benefit was most substantial among patients undergoing aortic valve repair or replacement with or without associated CABG (more than seven fewer MOMM events per 1,000, p < 0.0001). However, intensive care unit stay >72 hours was higher with CeOx.
• The results are limited by the study’s retrospective nature, despite careful adjustment for potential confounders. Hence only a correlation can be affirmed between CeOx and MOMM, but a causal relationship cannot be inferred.
• Moreover, the simple monitoring of CeOx is unlikely to produce a benefit in outcomes unless associated with corrective measures, and the extent of such interventions in the study population is unclear.

Conclusions:

• In this large, multicenter, retrospective propensity score-matched cohort study, CeOx monitoring was associated with small reductions in major organ morbidity and mortality after adult cardiac surgery.
• Randomized trials are warranted (with some underway) to determine the causal relationship between CeOx derangements, corrective interventions, and outcomes.