Cerebral desaturation events in the intensive care unit following cardiac surgery

Patients may be at high risk for hemodynamic instability in the early postoperative period, with subsequent poor cerebral perfusion and the development of postoperative cerebral oxygen desaturation events (CDEs). Intraoperative CDEs have been associated with postoperative adverse events. However, none of these studies examined the incidence of early postoperative cerebral desaturations. This study was designed to identify the incidence of CDEs (defined as a decrease in SctO2 to less than 60% for at least 60 seconds) in the immediate postoperative period following cardiac surgery.

Fifty-three moderate to high-risk patients undergoing elective cardiac surgery were enrolled in this observational study. Cerebral oximeter monitors were placed on all patients prior to induction of anesthesia and remained in place for 6 hours or until the patients were extubated postoperatively, whichever occurred first. Data were recorded from the cerebral oximeter, physiologic monitor and ventilator during the study period. Data were analyzed to identify the incidence of early postoperative CDEs, as well as association with subsequent clinical events.

The incidence of early postoperative CDEs was 53%. Sixty-four percent of these CDEs lasted for more than 1 hour. Patients with postoperative CDEs were more likely to have had intraoperative CDEs (P< 0.0001). Five out of 28 patients who experienced CDEs in the intensive care unit died while none of the patients without postoperative CDEs died (P = .053).

A high incidence of CDEs (53%) was found in the early post-cardiac surgery period. Larger studies are needed to determine whether postoperative CDEs are correlated with various physiologic events or are associated with adverse patient outcomes.