Comparison of Positive End-Expiratory Pressure versus Tidal Volume-Induced Ventilator-Driven Alveolar Recruitment Maneuver in Robotic Prostatectomy: A Randomized Controlled Study

Background: We evaluated the pulmonary effects of two ventilator-driven alveolar recruitment maneuver (ARM) methods during laparoscopic surgery. Methods: Sixty-four patients undergoing robotic prostatectomy were randomized into two groups: incrementally increasing positive end-expiratory pressure in a stepwise manner (PEEP group) versus tidal volume (VT group). We performed each ARM after induction of anesthesia in the supine position (T1), after pneumoperitoneum in the Trendelenburg position (T2), and after peritoneum desufflation in the supine position (T3). The primary outcome was change in end-expiratory lung impedance (EELI) before and 5 min after ARM at T3, measured by electrical impedance tomography. Results: The PEEP group showed significantly higher increasing EELI 5 min after ARM than the VT group at T1 and T3 (median [IQR] 460 [180,800] vs. 200 [80,315], p = 0.002 and 280 [170,420] vs. 95 [55,175], p = 0.004, respectively; PEEP group vs. VT group). The PEEP group showed significantly higher lung compliance and lower driving pressure at T1 and T3. However, there was no significant difference in EELI change, lung compliance, or driving pressure after ARM at T2. Conclusions: The ventilator-driven ARM by the increasing PEEP method led to greater improvements in lung compliance at the end of laparoscopic surgery than the increasing VT method.

Ventilator-associated lung injury in the intensive care unit and operating room – what's new?

The prophylaxis of ventilator-associated lung injury (VALI) and postoperative pulmonary complications (PPC) is of utmost importance to reduce complications both in the perioperative period of major surgery and in the intensive care unit (ICU).Protective approach to mechanical ventilation comprises a wide range of measures reducing the damage of the lung tissue associated with the stress and strain phenomena. The implementation of the strategy of high positive end-expiratory pressure (PEEP) in combination with alveolar recruitment maneuver has numerous limitations and requires further personalized approaches.When lung injury is self-induced by a patient, it becomes an important contributor to VALI and should be timely diagnosed and prevented both before initiation of mechanical support and during the restoration of spontaneous breathing. This review highlights the key mechanisms of VALI and current understanding of protective ventilation. The concept of damaging energy as well as approaches to the personalized optimization of respiratory settings are discussed in detail. Particular attention is paid to the prognostication of the risk factors of VALI and PPC.

Lung ultrasound score to determine the effect of fraction inspired oxygen during alveolar recruitment on absorption atelectasis in laparoscopic surgery: A randomized controlled trial

Background The intraoperative alveolar recruitment maneuver (ARM) efficiently treats atelectasis, but the effect of Fio 2 during ARM on atelectasis is uncertain. Here, we investigated this effect. Methods Patients undergoing elective laparoscopic surgery in the Trendelenburg position were randomized to low- (Fio 2 0.4; n=44) and high-Fio 2 (Fio 2 1.0, n=46) groups. ARMs were performed 1-min post tracheal intubation and post changes between supine and Trendelenburg positions during surgery. Intraoperative Fio 2 was set at 0.4 for both groups. Modified lung ultrasound (LUS) scores were calculated to assess lung aeration after inducing anesthesia and at surgery completion. The primary outcome was modified LUS score at the end of the surgery, and secondary outcomes were the intra- and postoperative Pao 2 to Fio 2 ratio and postoperative pulmonary complications. Results Both groups presented similar modified LUS scores before capnoperitoneum and ARM ( P =0.747). However, the postoperative modified LUS score was significantly lower in the low- than in the high-Fio 2 group (7.0±4.1 vs 11.7±4.2, mean difference 4.7, 95% CI 2.96–6.44, P <0.001). Significant atelectasis postoperatively was more common in the high-Fio 2 group (relative risk 1.77, 95% CI 1.27‒2.47, P <0.001). Intra- and postoperative Pao 2 to Fio 2 were similar and no postoperative pulmonary complications occurred. Atelectasis occurred more frequently when ARM was performed with high than with low Fio 2 . High-Fio 2 did not benefit oxygenation. Conclusions In patients undergoing laparoscopic surgery in the Trendelenburg position, absorption atelectasis occurred more frequently when the ARM was performed with high rather than low Fio 2 . No oxygenation benefit was observed in the high-Fio 2 group.

The effect of the fraction of inspired oxygen during alveolar recruitment on absorption atelectasis in laparoscopic surgery: A randomized, controlled trial

Background The intraoperative alveolar recruitment maneuver (ARM) efficiently treats atelectasis, but the effect of Fio2 during ARM on atelectasis is uncertain. Here, we investigated this effect. Methods Patients undergoing elective laparoscopic surgery in the Trendelenburg position were randomized to low- (Fio2 0.4; n = 44) and high-Fio2 (Fio2 1.0, n = 46) groups. ARMs were performed 1-min post tracheal intubation and post changes between supine and Trendelenburg positions during surgery. Intraoperative Fio2 was set at 0.4 for both groups. Modified lung ultrasound (LUS) scores were calculated to assess lung aeration after inducing anesthesia and at surgery completion. The primary outcome was modified LUS score at the end of the surgery, and secondary outcomes were the intra- and postoperative Pao2 to Fio2 ratio and postoperative pulmonary complications. Results Both groups presented similar modified LUS scores before capnoperitoneum and ARM (P = 0.747). However, the postoperative modified LUS score was significantly lower in the low- than in the high-Fio2 group (7.0 ± 4.1 vs 11.7 ± 4.2, mean difference 4.7, 95% CI 2.96–6.44, P < 0.001). Significant atelectasis postoperatively was more common in the high-Fio2 group (relative risk 1.77, 95% CI 1.27‒2.47, P < 0.001). Intra- and postoperative Pao2 to Fio2 were similar and no postoperative pulmonary complications occurred. Atelectasis occurred more frequently when ARM was performed with high than with low Fio2. High-Fio2 did not benefit oxygenation. Conclusions In patients undergoing laparoscopic surgery in the Trendelenburg position, absorption atelectasis occurred more frequently when the ARM was performed with high rather than low Fio2. No oxygenation benefit was observed in the high-Fio2 group. Trial registration: ClinicalTrials.gov, NCT03943433. Registered 7 May 2019, https://clinicaltrials.gov/ct2/show/NCT03943433