Postoperative Changes in Pulmonary Function after Valve Surgery: Oxygenation Index Early after Cardiopulmonary Is a Predictor of Postoperative Course.

Objective: To determine pulmonary functional changes that predict early clinical outcomes in valve surgery requiring long cardiopulmonary bypass (CPB).

Methods: This retrospective study included 225 consecutive non-emergency valve surgeries with fast-track cardiac anesthesia between January 2014 and March 2020. Blood gas analyses before and 0, 2, 4, 8, and 14 h after CPB were investigated.

Results: Median age and EuroSCORE II were 71.0 years (25-75 percentile: 59.5-77.0) and 2.46 (1.44-5.01). Patients underwent 96 aortic, 106 mitral, and 23 combined valve surgeries. The median CPB time was 151 min (122-193). PaO/FiO and AaDO/PaO significantly deteriorated two hours, but not immediately, after CPB (both < 0.0001). Decreased PaO/FiO and AaDO/PaO were correlated with ventilation time (r = 0.318 and 0.435) and intensive care unit (ICU) (r = 0.172 and 0.267) and hospital stays (r = 0.164 and 0.209). Early and delayed extubations (<6 and >24 h) were predicted by PaO/FiO (377.2 and 213.1) and AaDO/PaO (0.683 and 1.680), measured two hours after CPB with acceptable sensitivity and specificity (0.700-0.911 and 0.677-0.859).

Conclusions: PaO/FiO and AaDO/PaO two hours after CPB were correlated with ventilation time and lengths of ICU and hospital stays. These parameters suitably predicted early and delayed extubations.