Newly Published
Perioperative Medicine  |   November 2019
Positive End-expiratory Pressure and Distribution of Ventilation in Pneumoperitoneum Combined with Steep Trendelenburg Position
Author Notes
  • From the Department of Anesthesiology, Shimane University, Faculty of Medicine, Izumo, Japan (A.S., N.K., T.F., K.U., T.N., Y.S.), and the Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Center, Rostock, Germany (S.H.B., A.D.W.).
  • Submitted for publication December 26, 2018. Accepted for publication October 21, 2019.
    Submitted for publication December 26, 2018. Accepted for publication October 21, 2019.×
  • Correspondence: Address correspondence to Dr. Shono: Department of Anesthesiology, Shimane University Hospital, Enya 89-1, Izumo, Shimane, Japan. atsuko929shono@yahoo.co.jp. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Perioperative Medicine / Respiratory System
Perioperative Medicine   |   November 2019
Positive End-expiratory Pressure and Distribution of Ventilation in Pneumoperitoneum Combined with Steep Trendelenburg Position
Anesthesiology Newly Published on November 21, 2019. doi:https://doi.org/10.1097/ALN.0000000000003062
Anesthesiology Newly Published on November 21, 2019. doi:https://doi.org/10.1097/ALN.0000000000003062
Abstract

Editor’s Perspective:

What We Already Know about This Topic:

  • Pneumoperitoneum and steep Trendelenburg during laparoscopic prostatectomy shift the diaphragm cephalad and cause atelectasis in the dorsal lungs

  • The ability of positive end-expiratory pressure to mitigate these effects remains controversial

What This Article Tells Us That Is New:

  • In patients undergoing robot-assisted laparoscopic prostatectomy, 15 but not 5 cm H2O of positive end-expiratory pressure increased ventilation in the dorsal parts of the lung, resulting in more normal lung mechanics and gas exchange

  • High positive end-expiratory pressure did not improve postoperative lung function

Background: Pneumoperitoneum and a steep Trendelenburg position during robot-assisted laparoscopic prostatectomy have been demonstrated to promote a cranial shift of the diaphragm and the formation of atelectasis in the dorsal parts of the lungs. However, neither an impact of higher positive end-expiratory pressure (PEEP) on preserving the ventilation in the dorsal region nor its physiologic effects have been fully examined. The authors hypothesized that PEEP of 15 cm H2O during robot-assisted laparoscopic prostatectomy might maintain ventilation in the dorsal parts and thus improve lung mechanics.

Methods: In this randomized controlled study, 48 patients undergoing robot-assisted laparoscopic prostatectomy were included in the analysis. Patients were assigned to the conventional PEEP (5 cm H2O) group or the high PEEP (15 cm H2O) group. Regional ventilation was monitored using electrical impedance tomography before and after the establishment of pneumoperitoneum and 20° Trendelenburg position during the surgery. The primary endpoint was the regional ventilation in the dorsal parts of the lungs while the secondary endpoints were lung mechanics and postoperative lung function.

Results: Compared to that in the conventional PEEP group, the fraction of regional ventilation in the most dorsal region was significantly higher in the high PEEP group during pneumoperitoneum and Trendelenburg position (mean values at 20 min after taking Trendelenburg position: conventional PEEP, 5.5 ± 3.9%; high PEEP, 9.9 ± 4.7%; difference, –4.5%; 95% CI, –7.4 to –1.6%; P = 0.004). Concurrently, lower driving pressure (conventional PEEP, 14.9 ± 2.5 cm H2O; high PEEP, 11.5 ± 2.8 cm H2O; P < 0.001), higher lung dynamic compliance, and better oxygenation were demonstrated in the high PEEP group. Postoperative lung function did not differ between the groups.

Conclusions: Application of a PEEP of 15 cm H2O resulted in more homogeneous ventilation and favorable physiologic effects during robot-assisted laparoscopic prostatectomy but did not improve postoperative lung function.