Reduced cerebral oxygen saturation measured by absolute cerebral oximetry during thoracic surgery correlates with postoperative complications

Regional cerebral oxygen saturation (SctO2) has recently been shown to decrease significantly during thoracic surgery. The present study investigates whether these desaturations are related to postoperative complications. Fifty patients undergoing thoracic surgery with a single-lung ventilation (SLV) of > 45 min duration were enrolled. Regional cerebral oxygen saturation was measured using absolute oximetry; standard clinical variables, and SOFA and Clavien scores were recorded. Correlation between minimum SctO2 during SLV and postoperative complication scores was analysed using Pearson's correlation test, chi(2) test, and logistic regression. Forty-seven patients underwent lobectomy, two patients a pneumonectomy and 1 patient a chest wall resection. Eighty-two per cent of the patients had a decrease in SctO2 of > 15% from baseline value, and 10% of the patients had a minimal absolute SctO2 value between 45% and 55%. The minimal absolute SctO2 values during SLV correlated with the Clavien score (R-2=0.098, P=0.0201) and the non-respiratory SOFA score (R-2=0.090, P=0.0287). By defining a threshold of SctO2=65%, the odds ratio of having a non-respiratory organ failure was 2.37 (95% CI 1.18-4.39, P=0.043) and a complication according to the Clavien score (Clavien score > 0) was 3.19 (95% CI 1.60-6.34, P=0.0272). Thoracic surgery with SLV seemed to be associated with a significant decrease in SctO2, and minimal SctO2 values correlated positively with postoperative complications.