Comprehensive pulmonary function parameters including SVC/FVC (adjusted OR 1.22; 95% CI 0.61-2.35; p=0.56) did not independently predict prolonged mechanical ventilation after isolated CABG.
Cohort (n=228)
No
Do comprehensive pulmonary function test parameters (SVC/FVC and KCO) improve prediction of prolonged mechanical ventilation after isolated CABG beyond standard spirometry?
Comprehensive pulmonary function test parameters (SVC/FVC and KCO) do not improve preoperative risk stratification for prolonged mechanical ventilation after CABG beyond standard spirometry (FEV1%).
Effect estimate: OR 1.22 (95% CI 0.61-2.35)
p-value: p=0.56
Abstract Objective Prolonged mechanical ventilation (≥24 hours) after cardiac surgery increases morbidity, mortality, and healthcare costs. While FEV1 and DLCO have been demonstrated to be independent predictors of post operative pulmonary complications, additional pulmonary function test (PFT) measures, slow vital capacity to forced vital capacity ratio (SCV/FVC) and carbon monoxide transfer coefficient (KCO), are used in practice to characterize pulmonary pathophysiology, but have not been studied as independent predictors of prolonged mechanical ventilation following cardiac surgery. We hypothesized that these additional parameters would independently predict prolonged ventilation and improve risk stratification beyond standard spirometry. Methods We conducted a single center retrospective cohort study of 228 adults undergoing isolated CABG with preoperative PFTs between 2023 and 2025. Prolonged ventilation was defined as mechanical ventilation ≥24 hours postoperatively. We performed multivariable logistic regression to assess whether SVC/FVC and KCO independently predicted prolonged ventilation after adjusting for age, FEV1%, and presence of chronic lung disease (CLD). Complete data were available for 220 patients (96.5%) for SVC/FVC and 131 patients (57.5%) for KCO analysis. Model discrimination was assessed using area under the receiver operating characteristic curve. We compared a Standard Model (age + FEV1% + CLD) to a Comprehensive Model (Standard + SVC/FVC) using likelihood ratio and Delong test. Secondary analysis examined postoperative reintubation. Results The cohort had a mean age of 63.8± 10.1 years, 76% were male and 42% had CLD. Prolonged ventilation occurred in 23 patients (10.1%) and reintubation in 18 patients (7.9%) with substantial overlap (83%). Neither SVC/FVC (adjusted OR 1.22 0.61, 2.35, p = 0.56) nor KCO (adjusted OR 0.89 0.41, 1.81, p = 0.74) independently predicted prolonged ventilation. FEV1% remained the only significant predictor (OR 0.973 0.945, 0.999, p = 0.047). The Standard Model demonstrated modest discrimination (AUC 0.634 0.50, 0.768. Adding SVC/FVC provided no improvement (Comprehensive Model ΔAUC=0.001, p = 0.97). Conclusions Comprehensive PFT parameters (SVC/FVC and KCO) did not independently predict prolonged mechanical ventilation after isolated CABG when adjusted for standard spirometry. These findings suggest that routine collection of these parameters may not add clinical value for preoperative risk stratification. FEV1% alone appears sufficient for preoperative pulmonary risk assessment in patients undergoing cardiac surgery, thus supporting current practice patterns. This abstract is funded by: None
Nickles et al. (2026) conducted a cohort in Adults undergoing isolated CABG (n=228). Comprehensive PFT parameters (SVC/FVC and KCO) vs. Standard spirometry (age + FEV1% + CLD) was evaluated on Prolonged mechanical ventilation (≥24 hours postoperatively) (OR 1.22, 95% CI 0.61-2.35, p=0.56). Comprehensive pulmonary function parameters including SVC/FVC (adjusted OR 1.22; 95% CI 0.61-2.35; p=0.56) did not independently predict prolonged mechanical ventilation after isolated CABG.