Newly Published
Perioperative Medicine  |   July 2020
Body Habitus and Dynamic Surgical Conditions Independently Impair Pulmonary Mechanics during Robotic-assisted Laparoscopic Surgery: A Cross-Sectional Study
Author Notes
  • From the Departments of Anesthesiology (W.G.T., M.W.B., A.F.F., S.P.B.) and Surgery (S.M., S.P.) and the Division of Pulmonary Disease and Critical Care Medicine (A.E.D.), University of Vermont Medical Center, Burlington, Vermont; the Larner College of Medicine, University of Vermont, Burlington, Vermont (W.G.T., S.M., C.L., M.N.R., S.P., T.P.A., A.E.D., J.H.T.B., S.P.B.); and Midwestern University, Glendale, Arizona (A.B.).
  • Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).
    Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).×
  • Part of the work presented in this article has been presented at the Anesthesiology meeting in Orlando, Florida, October 20, 2019; the International Anesthesia Research Society Meeting in Montreal, Canada, May 20, 2019; and the Academic Surgical Congress in Houston, Texas, February 6, 2019.
    Part of the work presented in this article has been presented at the Anesthesiology meeting in Orlando, Florida, October 20, 2019; the International Anesthesia Research Society Meeting in Montreal, Canada, May 20, 2019; and the Academic Surgical Congress in Houston, Texas, February 6, 2019.×
  • Submitted for publication November 5, 2019. Accepted for publication May 29, 2020.
    Submitted for publication November 5, 2019. Accepted for publication May 29, 2020.×
  • Correspondence: Address correspondence to Dr Bender: University of Vermont Medical Center, Department of Anesthesiology, ACC-WP2, 111 Colchester Ave., Burlington, Vermont 05401. Stephen.Bender@uvmhealth.org. Anesthesiology’s articles are made freely accessible to all readers on www.anesthesiology.org, for personal use only, 6 months from the cover date of the issue.
Article Information
Perioperative Medicine / Airway Management / Gastrointestinal and Hepatic Systems / Respiratory System
Perioperative Medicine   |   July 2020
Body Habitus and Dynamic Surgical Conditions Independently Impair Pulmonary Mechanics during Robotic-assisted Laparoscopic Surgery: A Cross-Sectional Study
Anesthesiology Newly Published on July 9, 2020. doi:https://doi.org/10.1097/ALN.0000000000003442
Anesthesiology Newly Published on July 9, 2020. doi:https://doi.org/10.1097/ALN.0000000000003442
Abstract

Background: Body habitus, pneumoperitoneum, and Trendelenburg positioning may each independently impair lung mechanics during robotic laparoscopic surgery. This study hypothesized that increasing body mass index is associated with more mechanical strain and alveolar collapse, and these impairments are exacerbated by pneumoperitoneum and Trendelenburg positioning.

Methods: This cross-sectional study measured respiratory flow, airway pressures, and esophageal pressures in 91 subjects with body mass index ranging from 18.3 to 60.6 kg/m2. Pulmonary mechanics were quantified at four stages: (1) supine and level after intubation, (2) with pneumoperitoneum, (3) in Trendelenburg docked with the surgical robot, and (4) level without pneumoperitoneum. Subjects were stratified into five body mass index categories (less than 25, 25 to 29.9, 30 to 34.9, 35 to 39.9, and 40 or higher), and respiratory mechanics were compared over surgical stages using generalized estimating equations. The optimal positive end-expiratory pressure settings needed to achieve positive end-expiratory transpulmonary pressures were calculated.

Results: At baseline, transpulmonary driving pressures increased in each body mass index category (1.9 ± 0.5 cm H2O; mean difference ± SD; P < 0.006), and subjects with a body mass index of 40 or higher had decreased mean end-expiratory transpulmonary pressures compared with those with body mass index of less than 25 (–7.5 ± 6.3 vs. –1.3 ± 3.4 cm H2O; P < 0.001). Pneumoperitoneum and Trendelenburg each further elevated transpulmonary driving pressures (2.8 ± 0.7 and 4.7 ± 1.0 cm H2O, respectively; P < 0.001) and depressed end-expiratory transpulmonary pressures (–3.4 ± 1.3 and –4.5 ± 1.5 cm H2O, respectively; P < 0.001) compared with baseline. Optimal positive end-expiratory pressure was greater than set positive end-expiratory pressure in 79% of subjects at baseline, 88% with pneumoperitoneum, 95% in Trendelenburg, and ranged from 0 to 36.6 cm H2O depending on body mass index and surgical stage.

Conclusions: Increasing body mass index induces significant alterations in lung mechanics during robotic laparoscopic surgery, but there is a wide range in the degree of impairment. Positive end-expiratory pressure settings may need individualization based on body mass index and surgical conditions.

Editor’s Perspective:

What We Already Know about This Topic:

  • Prior studies suggest that intraoperative use of standardized tidal volumes based on ideal body weight are beneficial. However, attempts to define optimal positive end-expiratory pressure levels remain elusive given varying effects of body habitus and dynamic surgical conditions (pneumoperitoneum and Trendelenberg positioning).

  • Using esophageal manometry, the authors partitioned respiratory mechanical properties into lung and chest wall components in patients undergoing robotic laparoscopic surgery to assess the effects of obesity, pneumoperitoneum and Trendelenberg positioning on transpulmonary driving pressures and estimate optimal positive end-expiratory pressure for a given degree of obesity or surgical condition.

What This Article Tells Us That Is New:

  • Obese patients demonstrated increased driving pressures and decreased mean end-expiratory transpulmonary pressures. Pneumoperitoneum and Trendelenberg position further accentuated these differences. The optimal positive end-expiratory pressure was greater than set positive end-expiratory pressure in most subjects at all stages, ranging from 0 to 36.6 cm H2O.

  • Intraoperative positive end-expiratory pressure settings should account for dynamic changes in transpulmonary driving and end-expiratory pressures related to these factors. How best to accomplish this clinically remains uncertain.