Pulmonary Resection SurgerySIMPLE-PEEPNCT07851740
BMI-Adjusted PEEP During One-Lung Ventilation in Thoracic Surgery
A study testing Fixed PEEP and BMI-adjusted PEEP in people with Pulmonary Resection Surgery and One Lung Ventillation (OLV), run by Jesús Manuel Nieves Alonso at 4 sites in Spain.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Pulmonary Resection Surgery, One Lung Ventillation (OLV), General Anesthetic
- What is being tested?
- Fixed PEEP and BMI-adjusted PEEP
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 150 participants
- Where
- 4 sitesSpain
- Study dates
- 7 Oct 2026to 30 Mar 2028
- Phase
- Interventional
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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.
Who cannot join
- 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.
Trial locations and contacts
4 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Spain4 sites, 4 recruiting
- Not yet recruiting
Hospital Clinic Barcelona
Barcelona, Catalonia, 08036
Manuel L López, LOPEZ10@clinic.cat
- Not yet recruiting
Hospital de la Santa Creu i Sant Pau
Barcelona, Catalonia, 08041
Ana P Parera, AParera@santpau.cat
- Recruiting
Hospital Universitario de La Princesa
Madrid, Madrid, 28006
Jesús M Nieves Alonso, MD, +34915202540, jesusmna@gmail.com
- Not yet recruiting
Hospital General Universitario Geogorio Marañón
Madrid, Madrid, 28007
Estrela C Caamaño, estrelacaamano@gmail.com
About this study
Official title: Effect of Body Mass Index-Adjusted Positive End-Expiratory Pressure on Respiratory Mechanics During One-Lung Ventilation in Thoracic Surgery
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.
- Being tested
- Fixed PEEP, BMI-adjusted PEEP
- 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
- Medical subject headings
- Hypoxia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fixed PEEPProcedure or surgery
Fixed PEEP of 4 cmH2O
BMI-adjusted PEEPProcedure or surgery
BMI-adjusted PEEP calculated as BMI/3 cmH2O
| Study group | Role | What they receive |
|---|---|---|
| Fixed PEEP of 4 cmH2O | Active comparator | Not described Receives: Procedure: Fixed PEEP |
| BMI-adjusted PEEP calculated as BMI/3 cmH2O | Experimental | Not described Receives: Procedure: BMI-adjusted PEEP |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 20 minutes
Secondary outcomes (8)
Respiratory system compliance
Respiratory system compliance will be calculated at each applicable time point as tidal volume divided by driving pressure and expressed in mL/cmH2O
Measured: 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
Driving pressure will be assessed at 60 minutes after initiation of one-lung ventilation, when this time point is applicable, and at the actual end of one-lung ventilation, to evaluate the persistence of the physiological effect of the assigned PEEP strategy.
Measured: 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
Ventilatory mechanical power will be estimated from prospectively recorded ventilatory parameters using a prespecified calculation method appropriate to the ventilation mode and expressed in J/min.
Measured: 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
Intraoperative hypoxemia will be defined as SpO2 <90% sustained for at least 60 seconds during one-lung ventilation with baseline FiO2 0.6, or any episode of SpO2 <90% requiring immediate clinical intervention at the discretion of the attending anesthesiologist.
Measured: From initiation until completion of one-lung ventilation during the surgical procedure on Day 1 (up to 1 day).
Incidence of major ventilatory rescue
Major ventilatory rescue during the first 20 minutes after initiation of one-lung ventilation will be defined as any intervention that substantially modifies the assigned ventilatory strategy or respiratory mechanics, including modification of PEEP from the assigned value, recruitment maneuver, CPAP to the non-ventilated lung, temporary restoration of two-lung ventilation, or protocol interruption for safety reasons.
Measured: During the first 20 minutes after initiation of one-lung ventilation on Day 1.
Incidence of intraoperative hypotension
Intraoperative hypotension will be defined as mean arterial pressure <65 mmHg sustained for more than 1 minute.
Measured: Intraoperative/periprocedural period on Day 1, from induction of anesthesia until the end of surgery.
Requirement for intraoperative vasopressor support
Proportion of participants requiring vasopressor administration during the intraoperative period. Vasopressor use will be recorded as a measure of the hemodynamic safety of the assigned PEEP strategy.
Measured: Time Frame: Intraoperative/periprocedural period on Day 1, from induction of anesthesia until the end of surgery.
Incidence of postoperative pulmonary complications
Occurrence of at least one prespecified postoperative pulmonary complication, including acute respiratory failure, pneumonia, acute respiratory distress syndrome, atelectasis, pneumothorax, bronchopleural fistula, aspiration pneumonitis, pulmonary embolism, pleural empyema, bronchospasm, pleural effusion, or need for postoperative respiratory support or reintubation for respiratory deterioration. This outcome will be considered exploratory.
Measured: From the end of surgery until hospital discharge during the index hospitalization (estimated average duration: 3-10 days).
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Oct 2026
- Study start7 Oct 2026
- Primary completion1 Mar 2028 (estimated)
- Study completion30 Mar 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Pulmonary Resection SurgeryStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Supportive care
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 150 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Jesús Manuel Nieves Alonso
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Jesús Manuel Nieves Alonso, Fundación de Investigación Biomédica - Hospital Universitario de La Princesa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07851740
- Sponsor's protocol ID
- SIMPLE-PEEP
- Acronym
- SIMPLE-PEEP
- Status last verified
- Oct 2026
- First submitted
- 21 Sep 2026
- Last updated
- 9 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided