Obesity Alters Lung Mechanics in Robotic Surgery

Study Overview
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Brief Summary
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Intraoperative lung protective ventilation strategies using standardized tidal volumes based on predicted body weight have proven beneficial, but attempts to standardize positive end expiratory pressure (PEEP) settings have not robustly accounted for body habitus or dynamic surgical conditions. Laparoscopic abdominal surgery in Trendelenburg (head-down) is an increasingly common surgical modality that presents a unique physiological challenge to the pulmonary system. In order to delineate the impact of body habitus, pneumoperitoneum, and surgical positioning on intraoperative pulmonary mechanics we conducted an observational study of patients undergoing robotic assisted laparoscopic abdominal surgery in Trendelenburg position. Using esophageal manometry, we partitioned the mechanical properties of the respiratory system into its lung and chest wall components and evaluated the effects of pneumoperitoneum, surgical position, and body mass index (BMI) on transpulmonary pressures, airway and transpulmonary driving pressures, and lung elastance. We hypothesized that increasing BMI would be associated with evidence of increasing atelectasis, increased driving pressures, and elevated lung elastance and that these changes would be exacerbated by pneumoperitoneum and Trendelenburg positioning.

Official Title
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Dynamic Surgical Conditions and Body Habitus Independently Impair Pulmonary Mechanics During Robotic Assisted Laparoscopic Surgery: A Cross-Sectional Study

Conditions
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Obesity, Surgery, Anesthesia

Intervention / Treatment
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* Other: no intervention


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Inclusion criteria were presentation for robotic assisted laparoscopic abdominal surgery in the supine position, age ≥ 18 years, and ability to provide informed consent Exclusion Criteria: Exclusion criteria included intrinsic lung disease, ≥ 20 pack year smoking history, reactive airways disease, home oxygen requirement, inability to provide informed consent, emergent surgery, or esophageal pathology (i.e., strictures, varices, history of esophageal dilatation or surgery).

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Lean<br>BMI < 25 | Other: no intervention<br>* no intervention - observational only<br>|
| overweight<br>BMI 25 - 29.9 | Other: no intervention<br>* no intervention - observational only<br>|
| class i obesity<br>BMI 30 -34.9 | Other: no intervention<br>* no intervention - observational only<br>|
| class ii obesity<br>BMI 35 - 39.9 | Other: no intervention<br>* no intervention - observational only<br>|
| class iii obesity<br>BMI >= 40 | Other: no intervention<br>* no intervention - observational only<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transpulmonary pressure |  | during the surgical procedure |