Mechanical Ventilation in Obese Surgical Patients

NCT07774065 | Recruiting

• 1 other identifier: 25-0341
• Study Type: interventional
• Target: 10
• Locations: 1 country
• Sites: 1

Brief Summary

The purpose of this study is to evaluate whether an intraoperative positive end-expiratory pressures (PEEP) setting strategy aimed at minimizing the mechanical power delivered to the lungs via transpulmonary pressure improves postoperative outcomes in obese patients undergoing conventional laparoscopic or robotic-assisted surgery. The objectives are to determine whether this strategy reduces immediate postoperative hypoxemia, and to assess whether it mitigates lung injury as reflected by relevant blood biomarkers.

Conditions

Obese

Keywords

Robotic Surgery; Body Mass Index (BMI) ≥ 35 kg/m2; Laparoscopic Surgery; Obesity

Outcome Measures

Primary Outcomes (2)

• Peripheral Oxygen Saturation (SpO₂) Following Extubation

  Peripheral oxygen saturation (SpO₂) will be measured by pulse oximetry at least every 15 minutes during the first hour following extubation. SpO₂ will be recorded as a percentage (%).

  First hour following extubation (assessed at least every 15 minutes)

• Fraction of Inspired Oxygen (FiO₂) Following Extubation

  Fraction of inspired oxygen (FiO₂) will be recorded at least every 15 minutes during the first hour following extubation. FiO₂ will be recorded as a percentage (%).

  First hour following extubation (assessed at least every 15 minutes)

Secondary Outcomes (3)

• Highest Severity of Postoperative Pulmonary Complication (PPC)

  Postoperative Day 7 or hospital discharge, whichever occurs first

• Incidence of Grade 3 and Grade 4 Postoperative Pulmonary Complications

  Within 30 days after surgery

• Duration of Postoperative Respiratory Support

  From surgery until discontinuation of supplemental oxygen therapy and/or respiratory support, up to 30 days postoperatively

Other Outcomes (8)

• Major Extrapulmonary Complications

  Within 30 days after surgery

• All-Cause Mortality

  Postoperative Day 30

• Length of Stay in the Post-Anesthesia Care Unit (PACU)

  At 3 hours after PACU admission

Study Arms (2)

Transpulmonary Pressure-Guided Individualized PEEP

EXPERIMENTAL

A transpulmonary-guided individualized positive end-expiratory pressure (PEEPPTP) will be set as follows: (A) The intervention is initiated by a recruitment maneuver consisting of 5 cmH2O-stepwise (30 sec) PEEP increases until either maximum PEEP=30 cmH2O or end-inspiratory PTP\>25 cmH2O is reached. Settings: volume-controlled ventilation, VT=7ml/kg, I:E=1:1, inspiratory pause=20%, RR=10bpm, FiO2=80%. (B) Following recruitment, PEEP will be set to the value used immediately before the recruitment maneuver and PEso-EE assessed. PEEPPTP=PEso-EE+1-2 cmH2O. (C) PEEP will then be set for 30 sec at the highest value achieved during recruitment, followed by (D) PEEPPTP. Individualized PEEP-setting will be performed after: (1) induction of anesthesia, (2) pneumoperitoneum and final surgical position, including Trendelenburg and robot docking, (3) significant airway pressure changes or \>15% reduction in compliance (CRS=VT/DP), and (4) before extubation.

Procedure: Standard PEEP (8 cmH₂O)

Control Group - Standard Intraoperative PEEP

NO INTERVENTION

PEEP will be set to currently accepted settings for intraoperative PEEP=8cmH2O.

Interventions

Standard PEEP (8 cmH₂O) PROCEDURE

Participants will receive standard intraoperative mechanical ventilation with a fixed positive end-expiratory pressure (PEEP) of 8 cmH₂O maintained throughout the surgical procedure.

Transpulmonary Pressure-Guided Individualized PEEP

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥ 18 years;
• Body Mass Index (BMI) ≥ 35 kg/m2;
• Scheduled for laparoscopic surgery expected to exceed 2h (from incision to closure) under general anesthesia, as determined pre-operatively by the attending surgeon and surgical team based on typical scheduling estimates, prior experience, procedure type, planned surgical approach, and patient-specific factors.

You may not qualify if:

• Previous lung surgery;
• Invasive mechanical ventilation for \>30 minutes within the last 30 days prior to surgery;
• Receipt of immunosuppressive medication (chemotherapy or radiotherapy) up to two months prior to surgery;
• Neurological procedures or cardiac surgery;
• Need for one-lung ventilation or planned re-intubation following surgery;
• Requirement for intraoperative prone or lateral decubitus positioning;
• Enrollment in another interventional study or refusal to give written informed consent;
• Pregnancy, determined by anamnesis and/or laboratory testing;
• Persistent hemodynamic instability or intractable shock, considered hemodynamically unsuitable for the study by the patient's managing physician;
• Severe chronic obstructive pulmonary disease (COPD, defined as non-invasive ventilation and/or oxygen therapy at home or repeated systemic corticosteroid therapy for acute exacerbations of COPD);
• Severe cardiac disease (defined as New York Heart Association class III or IV, acute coronary syndrome or persistent ventricular tachyarrhythmia);
• Acute respiratory distress syndrome (according to the Berlin definition 2) expected to require prolonged postoperative mechanical ventilation;
• Severe pulmonary arterial hypertension (defined as systolic pulmonary artery pressure \> 40 mmHg)
• Intracranial injury, intracranial tumor, or neuromuscular disease;
• Known esophageal disease or anatomy that would preclude the safe placement of a standard orogastric tube

Sponsors & Collaborators

• The University of Texas Medical Branch, Galveston: lead

Study Sites (1)

University of Texas Medical Branch, Galveston

Galveston, Texas, 77555, United States

RECRUITING

MeSH Terms

Conditions

Obesity

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Marcos Vidal Melo

  University of Texas Medial Branch

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Negar Motayagheni

CONTACT

(409)772-1011; nemotaya@utmb.edu

Congli Zeng, MD, PhD

CONTACT

(409)772-1011; cozeng@utmb.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 11, 2026
• First Posted: August 19, 2026
• Study Start: July 29, 2026
• Primary Completion (Estimated): July 31, 2027
• Study Completion (Estimated): July 31, 2027
• Last Updated: August 19, 2026

Record last verified: 2026-08

Locations

US (1)