PREOPERATIVE PREDICTORS OF OPERATIVE MORBIDITY AND MORTALITY IN COPD PATIENTS UNDERGOING BILATERAL LUNG-VOLUME REDUCTION SURGERY

Bilateral volume reduction surgery (VRS) improves lung function for se lected patients with emphysema. However, predictors of outcome are not well defined. We reviewed the preoperative characteristics of the fir st 47 consecutive patients who underwent bilateral VRS at the Massachu setts General Hospital in order to define potential predictors of unac ceptable outcome. Preoperative data included spirometry, plethysmograp hy, diffusion of carbon monoxide (Dco), maximum inspiratory pressure ( MIP), maximum expiratory pressure, resting arterial blood gases (ABG), cardiopulmonary exercise testing with ABG and lactate sampling, and r adionuclide ventriculography. Prepulmonary and postpulmonary rehabilit ation 6-min walk tests (6MWT), and preoperative chest CT scans were al so obtained. Twenty-two subjects were male and 17 of the subjects were on the lung transplant list. Patient characteristics included age of 60.5+/-7.5 years, FEV(1) of 0.67+/-0.20 L, total lung capacity of 7.56 +/-1.7 L, Dco of 7.40+/-4.1 mL/min/mm Hg, and PaCO2 of 41.6+/-6.4 mm H g (mean+/-SD). The FEV(1), vital capacity, MIP, resting room air PaCO2 , prepulmonary and postpulmonary rehabilitation 6MWT, and PaCO2 at max imum oxygen consumption correlated with length of hospitalization (p < 0.05). Based on analysis of 41 of $7 patients for whom there were com plete data, the inability to walk more than 200 m on the 6MWT before o r after preoperative pulmonary rehabilitation, and resting PaCO2 great er than or equal to 45 mm Hg were the best predictors of an unacceptab le outcome. If either of these characteristics was present, six of 16 vs zero of 25 died (Fisher's Exact Test, p=0.0025, one-tailed) and 11 of 16 vs four of 25 had hospital courses >21 days (p<0.002). Both the 6MWT <200 m and resting PaCO2 greater than or equal to 45 mm Hg alone correlated with death (p=0.004 and p=0.012, respectively) and the rest ing PaCO2 greater than or equal to 45 mm Hg correlated with hospital d ays >21 (p=0.0002). In conclusion, the data suggest that the inability to walk at least 200 m in 6 min before or after pulmonary rehabilitat ion and a resting room air PaCO2 greater than or equal to 45 mm Hg are excellent preoperative predictors of unacceptable postoperative outco mes.