[Role of postoperative estimate of maximum oxygen uptake in predicting cardiorespiratory insufficiency in the immediate postoperative period in thoracic surgery].

We sought to determine if predicted post-operative maximal oxygen uptake (VO2max/kg-PPO) was associated to the occurrence of respiratory or cardiac failure within the 60 days following lung surgery and to evaluate its validity as operability criterion. We studied 47 patients with chronic air-flow limitation (COPD) with FEV1 > 0.8 1 and without hypercapnia, that underwent lung surgery. Age was 56 (SD 11) years, FEV1 = 1.8 (SD 0.5) 1 (61% predicted (SD 13%) and FEV1/FVC = 55 (SD 7.5). Ten patients presented serious cardiac or respiratory complications (3 died). Significant correlation with complications was found for RV, TL-COsb-PPO, VO2max/kg, resection size and VO2max/kg-PPO. VO2max/kg-PPO correlation (-0.73) was significantly higher (p = 0.0016) than all the pulmonary function test (PFT) correlation and than VO2max/kg correlation (p = 0.049) as well. Cut-off points, positive and negative predictive values were respectively: 12.6 ml/min/kg, 0.75 y 0.90% for VO2max/kg-PPO; 17 ml/min/kg 0.83 and 0.87 for VO2max/kg and 148%, 0.67 and 0.82 for RV (the best of the pulmonary function tests). Multivariable models did not improve discriminant power. We conclude that, out of the studied variables, VO2max/kg-PPO showed higher correlation with the complications sought than PFT or VO2max/kg. As criterion to predict cardiac or respiratory failure, with the observed prevalence, its negative predictive values is good, but its positive predictive value is relatively low. None parameter was able to predict all the complications.