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 (VO(2)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(2)max (ppoVO(2)max) 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 ppoVO(2)max within 1 standard deviation of the observed postoperative VO(2)max; group B (56 cases), patients with a difference between the observed postoperative VO(2)max and ppoVO(2)max greater than 1 standard deviation (underestimation); and group C (15 cases), patients with a difference between ppoVO(2)max and the observed postoperative VO(2)max 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 VO(2)max (p = 0.002).

CONCLUSIONS

The prediction of postoperative VO(2)max was not accurate in all patients. Those with a large amount of functional lung tissue removed during operation tended to have a postoperative VO(2)max greater than expected. Conversely, those patients with a small amount of functional lung tissue resected tended to have a postoperative VO(2)max lower than predicted.