Prediction of Postoperative Complications: Ventilatory Efficiency and Rest End-tidal Carbon Dioxide.

Background: Cardiopulmonary exercise testing parameters including ventilatory efficiency (V/VCO slope) are used for risk assessment of lung resection candidates. However, many patients are unable or unwilling to undergo exercise. V/VCO slope is closely related to the partial pressure of end-tidal carbon dioxide (PCO).