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

Abstract

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 (V_T 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 V_T 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. V_T 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 V_T method.

Keywords: alveolar recruitment maneuver; atelectasis; electrical impedance tomography; end-expiratory lung impedance; laparoscopy; lung compliance.

Figure 1

Study protocol. ABGA, arterial blood gas analysis; ARM, alveolar recruitment maneuver; EIT, electrical impedance tomography.

Figure 2

Flow diagram.

Figure 3

Comparisons of change in end-expiratory lung impedance from baseline during hyperinflation and postalveolar recruitment maneuver at each time point. T1: after induction of anesthesia in the supine position, T2: after pneumoperitoneum in the Trendelenburg position, T3: after peritoneum desufflation in the supine position. * Mann–Whitney U-test for the comparison between the two groups at each time point, p < 0.05.