Predicted versus observed maximum oxygen consumption early after lung resection

Background The objective of this study was to identify the predictors of underestimation and overestimation of postoperative maximum oxygen consumption (vo2 max). Methods A prospective analysis was performed on 229 patients who had 38 pneumonectomies, 171 lobectomies, and 20 segmentectomies. All patients performed a preoperative and postoperative (on average 9.2 days after surgery) maximal stair-climbing test. Predicted postoperative vo 2max (ppo vo2max) was calculated on the basis of the number of functioning segments removed during operation. The patients were divided into three groups: group A (158 cases), patients with a ppo vo 2max within 1 standard deviation of the observed postoperative vo 2max; group B (56 cases), patients with a difference between the observed postoperative vo 2max and ppo vo 2max greater than 1 standard deviation (underestimation); and group C (15 cases), patients with a difference between ppo vo 2max and the observed postoperative vo 2max greater than 1 standard deviation (overestimation). Univariate and multivariate analyses were performed. Results The only significant predictor of underestimation was a high percentage of functional parenchyma removed during operation (p< 0.0001). The significant predictors of overestimation were a low percentage of functional parenchyma removed during operation (p = 0.01) and a high preoperative vo2max (p = 0.002). Conclusions The prediction of postoperative vo 2max was not accurate in all patients. Those with a large amount of functional lung tissue removed during operation tended to have a postoperative vo 2max greater than expected. Conversely, those patients with a small amount of functional lung tissue resected tended to have a postoperative vo2max lower than predicted.