Background: To evaluate the clinical significance of predicting post-operative respiratory failure in patients with lung cancer using cardiopulmonary exercise test (CPET).
Methods: Before 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%.
Conclusions: CPET 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.