Role of quantitative CT in predicting hypoxemia and complications after lung lobectomy for cancer, with special reference to area of emphysema.

STUDY OBJECTIVES To determine the ability of quantitative CT, with special reference to area of emphysema, to predict early postoperative oxygenation capacity and outcome after lung lobectomy for cancer. METHODS Sixty-two consecutive patients scheduled to undergo lung lobectomy for cancer were enrolled in this study. The area of emphysema (< - 910 Hounsfield units) was measured on a three-dimensional CT lung model. Arterial oxygen saturation (Sao(2)) was calculated from Pao(2) measured 1 day before and 1 day after surgery with patients at rest breathing room air. A patient was considered to have recovered at the completion of a standardized management regimen. RESULTS Postoperative Sao(2) (postSao(2)) was predicted by the baseline value and the area of emphysema with the use of a regression equation. Ten of the 62 patients (16%) had postoperative cardiopulmonary complications (CPCs). The median time to postoperative recovery was 3 days (range, 1 to 17 days). Predicted postSao(2) and predicted postoperative FEV(1) were shown to be significant independent predictors of postoperative CPCs as well as postoperative recovery time. CONCLUSION Determining the area of emphysema by quantitative CT is useful in predicting early postoperative oxygenation capacity. Predicted oxygenation capacity and predicted ventilatory capacity independently affect perioperative outcomes. Therefore, using quantitative CT in combination with spirometry may improve risk prediction in patients undergoing lung lobectomy for cancer. However, the role of quantitative CT in grading nonemphysematous lung diseases, such as interstitial lung diseases, must be investigated.