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RecruitingNCT07774065Updated Aug 19, 2026

Mechanical Ventilation in Obese Surgical Patients

An interventional study of Standard PEEP (8 cmH₂O) in Obese, sponsored by The University of Texas Medical Branch, Galveston. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-19.

Sponsored by The University of Texas Medical Branch, Galveston · Not applicable, Interventional, and Prevention

Phase
Not applicable
Study type
Interventional
Enrollment
10
Allocation
Randomized
Ages
18 Years and older
Sex
All
01

Study 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.

02

Conditions studied

  • Obese

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Keywords

  • Robotic Surgery
  • Body Mass Index (BMI) ≥ 35 kg/m2
  • Laparoscopic Surgery
  • Obesity
03

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Inclusion criteria

  1. Age ≥ 18 years;
  2. Body Mass Index (BMI) ≥ 35 kg/m2;
  3. 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.

Exclusion criteria

Exclusion Criteria:

  1. Previous lung surgery;
  2. Invasive mechanical ventilation for >30 minutes within the last 30 days prior to surgery;
  3. Receipt of immunosuppressive medication (chemotherapy or radiotherapy) up to two months prior to surgery;
  4. Neurological procedures or cardiac surgery;
  5. Need for one-lung ventilation or planned re-intubation following surgery;
  6. Requirement for intraoperative prone or lateral decubitus positioning;
  7. Enrollment in another interventional study or refusal to give written informed consent;
  8. Pregnancy, determined by anamnesis and/or laboratory testing;
  9. Persistent hemodynamic instability or intractable shock, considered hemodynamically unsuitable for the study by the patient's managing physician;
  10. 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);
  11. Severe cardiac disease (defined as New York Heart Association class III or IV, acute coronary syndrome or persistent ventricular tachyarrhythmia);
  12. Acute respiratory distress syndrome (according to the Berlin definition 2) expected to require prolonged postoperative mechanical ventilation;
  13. Severe pulmonary arterial hypertension (defined as systolic pulmonary artery pressure > 40 mmHg)
  14. Intracranial injury, intracranial tumor, or neuromuscular disease;
  15. Known esophageal disease or anatomy that would preclude the safe placement of a standard orogastric tube
04

Study design

Phase
Not applicable
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Parallel assignment
Masking
None (open label)
Enrollment
10 participants (estimated)

Study arms

  • Experimental
    Transpulmonary Pressure-Guided Individualized PEEP

    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)

  • No intervention
    Control Group - Standard Intraoperative PEEP

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

Interventions

  • ProcedureStandard PEEP (8 cmH₂O)

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

05

What researchers measure

Primary outcomes

  1. 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 (%).

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

  2. 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 (%).

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

Secondary outcomes

  1. Highest Severity of Postoperative Pulmonary Complication (PPC)

    Highest severity grade of any postoperative pulmonary complication (PPC) experienced by the participant, assessed using the study-defined PPC severity classification.

    Time frame: Postoperative Day 7 or hospital discharge, whichever occurs first

  2. Incidence of Grade 3 and Grade 4 Postoperative Pulmonary Complications

    Number of participants who experience Grade 3 or Grade 4 postoperative pulmonary complications (PPCs) based on the study-defined PPC severity classification.

    Time frame: Within 30 days after surgery

  3. Duration of Postoperative Respiratory Support

    Duration of postoperative supplemental oxygen therapy and/or other respiratory support, including noninvasive or invasive respiratory support, measured from initiation to discontinuation.

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

Other outcomes

  1. Major Extrapulmonary Complications

    Number of participants experiencing major extrapulmonary postoperative complications.

    Time frame: Within 30 days after surgery

  2. All-Cause Mortality

    Number of all-cause mortality following surgery.

    Time frame: Postoperative Day 30

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

    Duration of stay in the post-anesthesia care unit following surgery.

    Time frame: At 3 hours after PACU admission

  4. Unexpected Intensive Care Unit (ICU) Admission

    Number of participants requiring an unplanned admission to the Intensive Care Unit following surgery.

    Time frame: During the index hospitalization, up to 30 days after surgery

  5. Hospital Length of Stay

    Duration of hospitalization following surgery.

    Time frame: Day of surgery, postoperative Day 7, and postoperative Day 30, or discharge, whichever occurs first

  6. ICU Length of Stay

    Duration of stay in the Intensive Care Unit among participants admitted to the ICU postoperatively.

    Time frame: Day of surgery, postoperative Day 7, and postoperative Day 30, or discharge, whichever occurs first

  7. Immediate Postoperative Adverse Events

    Number of adverse events occurring within 24 hours after surgery, including pneumothorax, hypoxemia, hypotension, use of vasoactive medications, and volume replacement.

    Time frame: Within 24 hours after surgery

  8. End-Inspiratory Transpulmonary Pressure Greater Than 25 cmH₂O

    Rate of participants with end-inspiratory transpulmonary pressure (PTP) greater than 25 cmH₂O during the perioperative period.

    Time frame: During surgery

06

Study locations

1 of 1 sites recruiting
  • University of Texas Medical Branch, Galveston
    Galveston, Texas 77555, United States
    Recruiting
07

Registry details

Key details

Study ID
NCT07774065
Lead sponsor
The University of Texas Medical Branch, Galveston
Responsible party
Sponsor
First posted
Aug 19, 2026
Start date
Jul 29, 2026
Primary completion
Jul 31, 2027 (estimated)
Completion
Jul 31, 2027 (estimated)
Last update
Aug 19, 2026

Study contacts

Negar Motayagheni
Contact
nemotaya@utmb.edu
(409)772-1011
Congli Zeng, MD, PhD
Contact
cozeng@utmb.edu
(409)772-1011
Marcos Vidal Melo
principal investigator · University of Texas Medial Branch

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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