In reply: The need to better understand the physiology of lung collapse during one-lung ventilation

Abstract

To the Editor, We would like to thank Dr. Pfitzner for his interest in our manuscript. Dr. Pfitzner seems to have misinterpreted our results when stating that: ‘‘...the volume of ‘gaseous influx’ into the non-ventilated lung from a measuring ambient air reservoir was greater when it occurred via the narrow-bore internal channel of a bronchial blocker (BB) than via the wide lumen of a double lumen endotracheal tube (DLETT)...’’. As described in our manuscript, ‘‘The mean (standard error of the mean [SEM]) Vresorb was similar in the DL-ETT and BB groups.’’ As stated by Dr. Pfitzner, ‘‘paradoxical ventilation’’ has been observed with DTETT, and we agree with him that it could not happen ‘‘to any meaningful degree via the long narrow-bore internal channel of the BB’’. Nevertheless, since the volume of ‘‘gaseous influx’’ into the non-operative lung is similar in both groups (DL-ETT and BB), it is unlikely that ‘‘paradoxical ventilation’’ had any significant impact on the phenomena reported in our manuscript. We do agree with Dr. Pfitzner that occluding the nonoperative bronchial port prior to pleural opening will hasten the lung collapse as described previously and in our more recent manuscript. While Dr. Pfitzner’s alternative recommendation to connect the open airway to an ambient pressure oxygen source in order to increase the speed of lung deflation seems reasonable, there is presently no experimental data to support this practice. Oxygen insufflation through the lumen of the non-ventilating lung has been described to increase oxygenation during onelung ventilation. Nevertheless, the impact of this procedure on the speed of lung deflation was not evaluated.