Ecomment. Could We Further Prevent Bronchopleural Fistulas after Pneumonec- Tomy? Ecomment. Postoperative Mechanical Ventilation for Patients Undergoing Pneu- Monectomy

We read with great interest the article by Toufektzian et al. regarding the relationship between postoperative mechanical ventilation and bronchopleural fistula (BPF) formation after pneumonectomy [1]. We congratulate the authors for their work and agree that every effort should be made to achieve the earliest possible extubation of the patient and that bronchial stump reinforcement is advisable in patients with a high risk for BPF. We would like only to add some comments which we think will be useful. Apart from the role of pre-existing infection, we must not neglect the possible role of some other factors in fistula formation. One of them is the cancer invasion of the bronchial stump. There are reports which suggest that residual carcinoma may impair healing of the stump [2]. So we strongly recommend the fresh frozen section of the stump. There is also a risk after preoperative irradiation of the mediastinum and the hilar area [3] and/or induction chemotherapy [4]. If we are required to proceed to mechanical ventilation, we must not also neglect that, apart from bronchial stump reinforcement, we have some other options that may reduce the risk of BPF. Firstly, we can use a low volume-low pressure model on ventilator settings. Respiratory rates must also be set at less 20 breaths/min. These settings can limit shear forces on the bronchial stump and prevent the generation of auto-positive end-expiratory pressure. A tidal volume of 5 ml/kg maintains the peak inspiratory pressure (PIP) below the threshold for injury which is approximately 35–40 cmH2O [5]. We can also use a jet ventilation mode after ventilation instead of conventional ventilation. This mode has reduced tidal volumes and PIPs are less than PIPs of conventional mode of ventilation. Randomized studies have suggested a lower incidence of postoperative barotrauma during jet ventilation [5]. During the abovementioned options, one must be very gentle in the bronchial toilet in order to prevent the application of high pressure on the stump by the tip of the catheter. We have anecdotally used one lung ventilation in patients at high risk for BPF formation, with very good results. This can be applied: (a) by a double lumen endotracheal tube at the remnant main bronchus, under continuous supervision or (b) by a single lumen endotracheal tube which is inserted into the main bronchus of the remnant lung with bronchoscopic assistance and periodic bronchoscopic control. But the usefulness of these modes needs to be proven in further studies. Finally, extracorporeal membrane oxygenation (ECMO), if available, has also been successfully used for severe respiratory failure after pneumonectomy, avoiding the baro-/volutauma of conventional modes of ventilation [5].