Oxygen Pulse as a Predictor of Cardiopulmonary Events in Lung Resection

Abstract

Traditional algorithms suggest a stepwise approach to the functional evaluation of candidates for lung resection. A cardiopulmonary exercise test is incorporated as a supplementary test for patients with borderline pulmonary predicted values, and sometimes as a first screening test for cardiac risk evaluation. To assess the predictive weight of exercise tests in noncardiac thoracic surgery, we retrospectively analyzed 99 patients (80 males) aged 67.8 ± 8.1 years who underwent lung resection after a cardiopulmonary exercise test. During basal spirometry, the mean predicted forced expiratory volume in the first second was 69.9% ± 18.6%, and predicted carbon monoxide diffusing capacity was 71.6% ± 20.5%. Peak oxygen consumption was 11.1 ± 3.2 mL·kg⁻¹·min⁻¹, oxygen pulse was 9 ± 2.8 mL·beat⁻¹, and minute ventilation/CO₂ output was 45.2 ± 7.7. Mean hospital stay was 10.4 days, and intensive care unit stay was 0.3 days. Postoperative complications occurred in 20 (20%) patients. On multivariate analysis, body mass index, a high level of exercise achieved during the cardiopulmonary exercise test, lower heart rate at peak exercise, and oxygen pulse correlated significantly with better postoperative outcome. Cardiopulmonary exercise tests are helpful for stratifying patients undergoing thoracic surgery. Perioperative complications seem to be strongly related to left ventricular function and physical performance.