Comparison of 5 vs 8 cmH₂O PEEP on Respiratory Mechanics in Prone Lumbar Surgery

NCT07545733 | Not Yet Recruiting

• 1 other identifier: REŞIT-PEEP-2026
• Study Type: interventional
• Target: 60
• Locations: 0 countries
• Sites: N/A

Brief Summary

This randomized controlled clinical trial aims to compare the effects of two different positive end-expiratory pressure (PEEP) levels (5 cmH₂O and 8 cmH₂O) on respiratory mechanics in patients undergoing lumbar spine surgery in the prone position under total intravenous anesthesia (TIVA). Prone positioning may adversely affect lung compliance and gas exchange, making optimal ventilatory strategies essential. Driving pressure and mechanical power are considered key determinants of ventilator-induced lung stress. This study will evaluate the impact of different PEEP levels on respiratory parameters and intraoperative physiological changes.

Conditions

Lumbar Disc Herniation; Spinal Surgery; Prone Position; General Anesthesia

Keywords

PEEP; Driving Pressure; Mechanical Power; PCV-VG Ventilation; Prone Position; Lung Protective Ventilation

Outcome Measures

Primary Outcomes (1)

• Driving Pressure (ΔP)

  Driving pressure (ΔP), calculated as the difference between plateau pressure (Pplat) and positive end-expiratory pressure (PEEP), will be used as the primary outcome to assess lung stress during mechanical ventilation.

  Intraoperative period (at predefined time points: T0, T2, T5)

Secondary Outcomes (6)

• Mechanical Power

  Intraoperative period (T0, T2, T5)

• Oxygenation (PaO₂/FiO₂ Ratio)

  Intraoperative period (T0, T2, T5)

• PaCO₂-EtCO₂ Gradient

  Intraoperative period (T0, T2, T5)

• Physiological Dead Space Fraction (VD/VT)

  Intraoperative period (T0, T2, T5)

• Dynamic Lung Compliance (Cdyn)

  Intraoperative period (all time points)

Study Arms (2)

PEEP-5 Group

EXPERIMENTAL

Participants in this group will receive mechanical ventilation with a positive end-expiratory pressure (PEEP) level of 5 cmH₂O during lumbar spine surgery in the prone position under total intravenous anesthesia (TIVA). Ventilation will be performed using PCV-VG mode with a target tidal volume of 6-8 mL/kg predicted body weight and respiratory rate adjusted to maintain normocapnia.

Device: Mechanical Ventilation (PEEP)

PEEP-8 Group

EXPERIMENTAL

Participants in this group will receive mechanical ventilation with a positive end-expiratory pressure (PEEP) level of 8 cmH₂O during lumbar spine surgery in the prone position under total intravenous anesthesia (TIVA). Ventilation will be performed using PCV-VG mode with a target tidal volume of 6-8 mL/kg predicted body weight and respiratory rate adjusted to maintain normocapnia.

Device: Mechanical Ventilation (PEEP)

Interventions

Mechanical Ventilation (PEEP) DEVICE

Mechanical ventilation will be applied using pressure-controlled ventilation with volume guarantee (PCV-VG) mode during prone lumbar surgery under total intravenous anesthesia (TIVA). Two different positive end-expiratory pressure (PEEP) levels (5 cmH₂O and 8 cmH₂O) will be used according to group allocation. Tidal volume will be set at 6-8 mL/kg predicted body weight, and respiratory rate will be adjusted to maintain normocapnia (EtCO₂ 35-40 mmHg).

Also known as: PCV-VG Ventilation, Lung Protective Ventilation

PEEP-5 Group; PEEP-8 Group

Eligibility Criteria

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

You may qualify if:

• Patients aged between 18 and 65 years
• American Society of Anesthesiologists (ASA) physical status I-II
• Scheduled for elective lumbar spine surgery in the prone position
• Planned general anesthesia with total intravenous anesthesia (TIVA)
• Ability to provide informed consent

You may not qualify if:

• Body mass index (BMI) ≥ 30 kg/m²
• History of significant pulmonary disease (e.g., COPD, asthma)
• Severe cardiovascular disease
• Pregnancy
• Known difficult airway
• Requirement for intraoperative vasopressor infusion due to hemodynamic instability
• Conversion to different surgical position or change in surgical plan
• Incomplete data or protocol deviation

Sponsors & Collaborators

• Harran University: lead

MeSH Terms

Conditions

Intervertebral Disc Displacement

Interventions

Respiration, Artificial; Positive-Pressure Respiration

Condition Hierarchy (Ancestors)

Spinal Diseases; Bone Diseases; Musculoskeletal Diseases; Hernia; Pathological Conditions, Anatomical; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Airway Management; Therapeutics; Resuscitation; Emergency Treatment; Respiratory Therapy

Study Officials

• Basak Pehlivan, Asoc Prof

  Harran University Faculty of Medicine, Department of Anesthesiology

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Basak Pehlivan, Assoc Prof

CONTACT

5054083199; bpehlivan@harran.edu.tr

Veli F Pehlivan, MD

CONTACT

5327696566; vfpehlivan@harran.edu.tr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: This is an open-label study. Due to the nature of the intervention (ventilator settings), masking of care providers and investigators is not feasible.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Model Details: Participants will be randomly assigned to one of two groups receiving either 5 cmH₂O or 8 cmH₂O PEEP during mechanical ventilation in prone lumbar surgery.

Study Record Dates

• First Submitted: April 16, 2026
• First Posted: April 22, 2026
• Study Start: May 1, 2026
• Primary Completion (Estimated): July 2, 2026
• Study Completion (Estimated): September 3, 2026
• Last Updated: April 29, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share