Does postoperative mechanical ventilation predispose to bronchopleural fistula formation in patients undergoing pneumonectomy?

A best evidence topic was written according to a structured protocol. The question addressed was whether postoperative mechanical ventilation has any effect on the incidence of development of bronchopleural fistulas (BPFs) in patients undergoing pneumonectomy. A total of 40 papers were identified using the reported search, of which 8, all retrospective, represented the best evidence to answer the clinical question. The authors, date, journal, country, study type, population, outcomes and key results are tabulated. Of the eight identified papers, six of them reported a statistically significant relationship between postoperative mechanical ventilation and the occurrence of bronchopleural fistula in patients undergoing pneumonectomy (P = 0.027-0.0001). In two of these studies, postoperative mechanical ventilation was identified during multivariate analysis as an independent predictor for the development of BPF after pneumonectomy (odds ratio 15.57 and 33.1), indicating a causal relationship whereas, in the other four reports, statistical significance was the result of univariate analysis. In another study, the difference between these two groups approached but did not reach statistical significance (P = 0.057). Finally, one study reported no association between postoperative mechanical ventilation and the development of post-pneumonectomy BPF (0.16). Apart from mechanical ventilation, pre-existing pleuropulmonary infection was reported by one study as an independent predictor for the development of post-pneumonectomy BPF whereas, in two other studies, its impact approached but did not reach statistical significance. Another study did not find any association between preoperative infection and postoperative BPF occurrence. In conclusion, the majority of the reported studies report a significant relationship between mechanical ventilation after pneumonectomy and the occurrence of BPF. Every effort should be made to achieve extubation at the earliest possible time to withdraw the effects of the continuous barotrauma on the bronchial stump, although its impact cannot be quantified. Performing pneumonectomy in the presence of infectious conditions may contribute to the development of postoperative BPF, but its role is less well defined.