BACKGROUNDTo evaluate the clinical significance of predicting post-operative respiratory failure in patients with lung cancer using cardiopulmonary exercise test (CPET).

METHODSBefore operation, 260 patients with lung cancer underwent CPET with incremental protocol. W%, VO₂%P, VO₂/kg, AT, MET, O₂ pulse, VTe, BF and VE were measured in the end of load exercise.

RESULTS(1) In patients after pneumonectomy, the values of the above indexes of CPET in the respiratory failure group were significantly lower than those in the non-respiratory failure group ( P < 0.05 or P < 0.01) except VTe. In patients after lobectomy, the values of 9 indexes of CPET in the respiratory failure group were similar to those in the non-respiratory failure group ( P > 0.05). However, when the patients after lobectomy were further divided into groups of upper and lower lobectomy, W% in the respiratory failure group was remarkably lower than that in the non-respiratory failure group after lower lobectomy ( P < 0.05). (2) Chi-Square test showed that abnormality of CPET indexes in different degrees was related to the morbidity of respiratory failure after pneumonectomy. Logistic regression showed that O₂ pulse < 80% and BF < 30/min correlated with the morbidity of post-operative respiratory failure. (3) For predicting post-operative respiratory failure, the sensitivity and specificity of VO₂%P < 60%, BF < 30/min, VE < 35 L/min were all more than 60% and their negative predictive values were all more than 90%.

CONCLUSIONSCPET is suitable to predict post-pneumonectomy respiratory failure. As a comprehensive index indicating cardiopulmonary function during exercise, VO₂%P < 60% should be selected to predict respiratory failure and evaluate indication of lung resection for patients with lung cancer.