Letters to the Editor: Letter to the Editor
To the Editor
While the recent article by Ferrando et al.1 focusing on lung-protective ventilation strategies for patients undergoing 1-lung ventilation did show increased oxygen arterial pressure (PaO2) in patients in whom the positive end-expiratory pressure (PEEP) was increased during 1-lung ventilation, the authors failed to assess outcomes, including underlying safety of the recruitment maneuver.
A recruitment maneuver plus PEEP could open the collapsed alveoli and prevent recollapse.2 However, static compliance may not be the best indication for ventilation because alveolar heterogeneity,3 including lung collapse and overdistention, often occur at the same time, especially in patients with bullae. The higher PaCO2 in the study group might be caused by further distention of already opened lung regions and thus the improvement of compliance does not necessarily indicate the optimal PEEP. Also, while in the study group, the PaCO2 was significantly higher (306 vs 231 mm Hg, P = 0.007) for most patients without impaired diffusion. When the PaO2 is >150 mm Hg, hemoglobin is nearly fully saturated and the pulse oximetry is nearly 100%, and thus the higher PaO2 is clinically not very important.
In addition, previous studies in patients undergoing pneumonectomy, higher airway pressure during 1-lung ventilation has been shown to be a risk factor for developing acute lung injury/acute respiratory distress syndrome.4 It would therefore be of greater clinical interest if Ferrando et al.1 had data describing postoperative complications between the 2 groups including barotrauma, postoperative atelectasis, pneumonia, and 1-month mortality. In the final analysis, the maneuvers performed during surgery should be directed at improving the outcomes of patients.
Yabing Zhang, MD
Deshui Yu, MD
Bin Liu, MD
Department of Anesthesiology
West China Hospital of Sichuan University
Chengdu, Sichuan, China
1. Ferrando C, Mugarra A, Gutierrez A, Carbonell JA, García M, Soro M, Tusman G, Belda FJ. Setting individualized positive end-expiratory pressure level with a positive end-expiratory pressure decrement trial after a recruitment maneuver improves oxygenation and lung mechanics during one-lung ventilation. Anesth Analg. 2014;118:657–65
2. Futier E, Constantin JM, Paugam-Burtz C, Pascal J, Eurin M, Neuschwander A, Marret E, Beaussier M, Gutton C, Lefrant JY, Allaouchiche B, Verzilli D, Leone M, De Jong A, Bazin JE, Pereira B, Jaber SIMPROVE Study Group. . A trial of intraoperative low-tidal-volume ventilation in abdominal surgery. N Engl J Med. 2013;369:428–37
3. Gattinoni L, D’Andrea L, Pelosi P, Vitale G, Pesenti A, Fumagalli R. Regional effects and mechanism of positive end-expiratory pressure in early adult respiratory distress syndrome. JAMA. 1993;269:2122–7
4. Jeon K, Yoon JW, Suh GY, Kim J, Kim K, Yang M, Kim H, Kwon OJ, Shim YM. Risk factors for post-pneumonectomy acute lung injury/acute respiratory distress syndrome in primary lung cancer patients. Anaesth Intensive Care. 2009;37:14–9