Reply from the authors: Reply

Abstract

Editor—We thank Dr Drummond for his interest in our article1Defresne AA Hans GA Goffin PJ et al.Recruitment of lung volume during surgery neither affects the postoperative spirometry nor the risk of hypoxaemia after laparoscopic gastric bypass in morbidly obese patients: a randomized controlled study.Br J Anaesth. 2014; 113: 501-507Abstract Full Text Full Text PDF PubMed Scopus (41) Google Scholar and particularly for his comment on our results on postoperative blood oxygenation. He also reminds us of the significance of functional residual capacity (FRC) and lung function tests, which is welcome and relevant because frequent misinterpretations are found in the literature. We would, however, like to clarify that we did not state, ‘General anaesthesia causes a reduction in functional residual capacity (FRC) that can last several days’ but rather, ‘General anaesthesia decreases functional residual capacity (FRC) and causes atelectasis. After upper abdominal surgery, FRC remains decreased in the immediate postoperative period and then recovers slowly over several days.’ Our sentences do not assume that the changes induced by general anaesthesia alone persist for several days but refer to the combined effects of anaesthesia and upper abdominal surgery. These effects are well described in the literature. Although most studies in the field were carried out after open abdominal surgery, computed tomography scan after upper abdominal laparoscopic surgery also showed atelectasis 24 h after surgery.2Eichenberger A Proietti S Wicky S et al.Morbid obesity and postoperative pulmonary atelectasis: an underestimated problem.Anesth Analg. 2002; 95: 1788-1792Crossref PubMed Scopus (379) Google Scholar, 3Talab HF Zabani IA Abdelrahman HS et al.Intraoperative ventilatory strategies for prevention of pulmonary atelectasis in obese patients undergoing laparoscopic bariatric surgery.Anesth Analg. 2009; 109: 1511-1516Crossref PubMed Scopus (182) Google Scholar We agree with Dr Drummond that the fact that we did not observe any reduction in FRC 24 h after surgery despite a decreased intraoperative compliance and no recruitment suggests that intra- and postoperative atelectasis are different entities and have a different pathophysiology. We also would like to take this opportunity to emphasize that our study remains so far the only study to have investigated the independent effect of recruitment manoeuvres in a lung-protective ventilation. Such studies are needed, as stated recently by Futier and colleagues.4Futier E Marret E Jaber S Perioperative positive pressure ventilation: an integrated approach to improve pulmonary care.Anesthesiology. 2014; 121: 400-408Crossref PubMed Scopus (77) Google Scholar We did not demonstrate any postoperative benefit of recruitment manoeuvres when combined with lung-protective ventilation during upper abdominal laparoscopic surgery. Two recent multicentre studies reported opposite clinical outcomes of lung-protective ventilation strategies including recruitment manoeuvres after open abdominal surgery.5Futier E Constantin JM Paugam-Burtz C IMPROVE Study Group et al.A trial of intraoperative low-tidal-volume ventilation in abdominal surgery.N Engl J Med. 2013; 369: 428-437Crossref PubMed Scopus (881) Google Scholar, 6PROVE Network Investigators for the Clinical Trial Network of the European Society of Anaesthesiology Hemmes SN Gama de Abreu M Pelosi P Schultz MJ High versus low positive end-expiratory pressure during general anaesthesia for open abdominal surgery (PROVHILO trial): a multicentre randomised controlled trial.Lancet. 2014; 384: 495-503Abstract Full Text Full Text PDF PubMed Scopus (441) Google Scholar Further studies are needed to determine the exact place or contribution of lung recruitment during intraoperative protective ventilation.7Goldenberg NM Steinberg BE Lee WL Wijeysundera DN Kavanagh BP Lung-protective ventilation in the operating room: time to implement?.Anesthesiology. 2014; 121: 184-188Crossref PubMed Scopus (39) Google Scholar J.L.J. has received a travel grant from Abbott and Fresenius-Kabi. G.A.H. has received a travel grant from MSD, Astra-Zeneca, and Fresenius-Kabi.