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

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

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.

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). PaO₂/FiO₂ and AaDO₂/PaO₂ significantly deteriorated two hours, but not immediately, after CPB (both p < 0.0001). Decreased PaO₂/FiO₂ and AaDO₂/PaO₂ were correlated with ventilation time (r² = 0.318 and 0.435) and intensive care unit (ICU) (r² = 0.172 and 0.267) and hospital stays (r² = 0.164 and 0.209). Early and delayed extubations (<6 and >24 h) were predicted by PaO₂/FiO₂ (377.2 and 213.1) and AaDO₂/PaO₂ (0.683 and 1.680), measured two hours after CPB with acceptable sensitivity and specificity (0.700-0.911 and 0.677-0.859).

PaO₂/FiO₂ and AaDO₂/PaO₂ two hours after CPB were correlated with ventilation time and lengths of ICU and hospital stays. These parameters suitably predicted early and delayed extubations.