BMI-Adjusted PEEP During One-Lung Ventilation in Thoracic Surgery

NCT07851740 | Not Yet Recruiting

• 1 other identifier: SIMPLE-PEEP
• Study Type: interventional
• Target: 150
• Locations: 1 country
• Sites: 4

Brief Summary

One-lung ventilation (OLV) is required during many thoracic surgical procedures and is associated with reduced functional residual capacity, atelectasis, ventilation-perfusion mismatch, hypoxemia, and potentially ventilator-induced lung injury. Lung-protective ventilation strategies include low tidal volumes, limitation of airway pressures, and positive end-expiratory pressure (PEEP), but the optimal PEEP level during OLV remains uncertain. Fixed PEEP is simple and reproducible but does not account for individual patient characteristics. Body mass index (BMI) is readily available before anesthesia and is associated with respiratory mechanics, making it a pragmatic candidate for simple PEEP individualization. SIMPLE-PEEP is a prospective, multicenter, pragmatic, open-label, randomized clinical trial including 150 adults undergoing elective pulmonary resection under general anesthesia requiring OLV. Participants will be randomized to either fixed PEEP of 4 cmH2O or BMI-adjusted PEEP calculated as BMI/3 cmH2O. Other key components of lung-protective ventilation will be standardized between groups. The primary outcome is driving pressure during the first 20 minutes of OLV, assessed at 5, 10, and 20 minutes after OLV initiation. Secondary outcomes include respiratory system compliance and other respiratory mechanics, estimated mechanical power, oxygenation, intraoperative hypoxemia and rescue maneuvers, hemodynamic safety, vasopressor requirements, and exploratory postoperative respiratory outcomes. No investigational medicinal product, additional invasive procedure, or study-specific advanced monitoring is required.

Conditions

Pulmonary Resection Surgery; General Anesthetic; One Lung Ventillation (OLV)

Keywords

One-lung ventilation; Thoracic surgery; Lung resection; Positive end-expiratory pressure; PEEP; Body mass index; BMI; Respiratory mechanics; Driving pressure; Respiratory system compliance; Lung-protective ventilation; Hypoxemia; Postoperative pulmonary complications

Outcome Measures

Primary Outcomes (1)

• Driving pressure during the primary T2-T4 window

  Driving pressure during the primary T2-T4 window, measured at 5, 10, and 20 minutes after initiation of one-lung ventilation and expressed in cmH2O. In conventional volume-controlled ventilation, driving pressure is calculated as plateau pressure minus applied PEEP. In pressure-regulated volume-targeted/volume-guaranteed modes, driving pressure is calculated as total end-inspiratory pressure minus applied PEEP.

  20 minutes

Secondary Outcomes (8)

• Respiratory system compliance

  At 5, 10, and 20 minutes after initiation of one-lung ventilation; at 60 minutes when applicable; and at the end of one-lung ventilation, all during the surgical procedure on Day 1.

• Driving pressure at 60 minutes and at the end of one-lung ventilation

  At 60 minutes after initiation of one-lung ventilation, when applicable, and at the end of one-lung ventilation.

• Estimated mechanical power during one-lung ventilation

  At 5, 10, and 20 minutes after initiation of one-lung ventilation; at 60 minutes when applicable; and at the end of one-lung ventilation, all during the surgical procedure on Day 1.

• Incidence of intraoperative hypoxemia during one-lung ventilation

  From initiation until completion of one-lung ventilation during the surgical procedure on Day 1 (up to 1 day).

• Incidence of major ventilatory rescue

  During the first 20 minutes after initiation of one-lung ventilation on Day 1.

Study Arms (2)

Fixed PEEP of 4 cmH2O

ACTIVE COMPARATOR

Procedure: Fixed PEEP

BMI-adjusted PEEP calculated as BMI/3 cmH2O

EXPERIMENTAL

Procedure: BMI-adjusted PEEP

Interventions

Fixed PEEP PROCEDURE

Fixed PEEP of 4 cmH2O

Fixed PEEP of 4 cmH2O

BMI-adjusted PEEP PROCEDURE

BMI-adjusted PEEP calculated as BMI/3 cmH2O

BMI-adjusted PEEP calculated as BMI/3 cmH2O

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 or older.
• Scheduled thoracic surgery for pulmonary resection requiring general anesthesia and one-lung ventilation.
• Written informed consent obtained before any study-specific procedure.

You may not qualify if:

• Simultaneous participation in another interventional clinical trial that could interfere with the protocol.
• Severe hemodynamic instability before the start of the procedure, defined as continuous vasopressor infusion or shock of any etiology.
• Severe restrictive lung disease, defined as total lung capacity \<50% of predicted or forced vital capacity \<50% of predicted.
• Body mass index \>45 kg/m2.

Sponsors & Collaborators

• Jesús Manuel Nieves Alonso: lead

Study Sites (4)

Hospital Clinic Barcelona

Barcelona, Catalonia, 08036, Spain

Location

Hospital de la Santa Creu i Sant Pau

Barcelona, Catalonia, 08041, Spain

Location

Hospital Universitario de La Princesa

Madrid, Madrid, 28006, Spain

Location

Hospital General Universitario Geogorio Marañón

Madrid, Madrid, 28007, Spain

Location

MeSH Terms

Conditions

Hypoxia

Condition Hierarchy (Ancestors)

Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Jesús M Nieves Alonso, MD

CONTACT

+34915202540; jesusmna@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: SUPPORTIVE CARE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Department of Anaesthesiology and Surgical Intensive Care

Study Record Dates

• First Submitted: September 21, 2026
• First Posted: October 1, 2026
• Study Start (Estimated): November 1, 2026
• Primary Completion (Estimated): March 1, 2028
• Study Completion (Estimated): March 30, 2028
• Last Updated: October 1, 2026

Record last verified: 2026-09

Locations

ES (4)