Comparison of 5 vs 8 cmH₂O PEEP on Respiratory Mechanics in Prone Lumbar Surgery
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Mechanical Ventilation (PEEP).
- Who it may be relevant to
- Registry conditions: Lumbar Disc Herniation, Spinal Surgery, Prone Position, General Anesthesia. Basic parameters: 18 years — 65 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- Center list to be confirmed — check the primary protocol.
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Official title
The Effect of Different PEEP Levels Accompanied by PCV-VG Mode on Respiratory Mechanics and Gas Exchange in Lumbar Surgeries Performed in the Prone Position Under TIVA
Overview
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.
Detailed description
Prone positioning during lumbar spine surgery is associated with increased intrathoracic pressure, reduced lung compliance, and impaired ventilation-perfusion matching, which may negatively affect respiratory mechanics and gas exchange. Mechanical ventilation strategies, particularly the application of positive end-expiratory pressure (PEEP), play a critical role in preventing atelectasis and optimizing oxygenation.
Pressure-controlled ventilation with volume guarantee (PCV-VG) is a modern ventilation mode that ensures target tidal volume delivery while minimizing airway pressures, thereby reducing the risk of ventilator-induced lung injury. In recent years, driving pressure (ΔP) and mechanical power have emerged as important parameters reflecting lung stress and injury during mechanical ventilation.
This prospective randomized controlled trial aims to evaluate the effects of two different PEEP levels (5 cmH₂O and 8 cmH₂O) on respiratory mechanics and gas exchange in patients undergoing lumbar spine surgery in the prone position under total intravenous anesthesia (TIVA). Patients will be randomly assigned into two groups receiving either 5 cmH₂O or 8 cmH₂O PEEP. Ventilation will be standardized using PCV-VG mode with a tidal volume of 6-8 mL/kg predicted body weight and respiratory rate adjusted to maintain normocapnia.
Hemodynamic parameters and respiratory variables, including peak airway pressure, plateau pressure, dynamic compliance, airway resistance, tidal volume, and end-tidal CO₂, will be recorded at predefined time points. Arterial blood gas analyses will be performed at selected intervals to assess gas exchange.
The primary outcome of the study is driving pressure (ΔP), while secondary outcomes include mechanical power, oxygenation parameters, PaCO₂-EtCO₂ gradient, and physiologic dead space fraction (VD/VT).
The findings of this study are expected to provide clinical evidence regarding the optimal PEEP level in prone lumbar surgery and contribute to improving intraoperative lung-protective ventilation strategies.
Interventions
- Device Mechanical Ventilation (PEEP)
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).
Primary outcome measures
- Driving Pressure (ΔP) [Time frame: Intraoperative period (at predefined time points: T0, T2, T5)]
Secondary outcome measures (6)
- Mechanical Power [Time frame: Intraoperative period (T0, T2, T5)]
- Oxygenation (PaO₂/FiO₂ Ratio) [Time frame: Intraoperative period (T0, T2, T5)]
- PaCO₂-EtCO₂ Gradient [Time frame: Intraoperative period (T0, T2, T5)]
- Physiological Dead Space Fraction (VD/VT) [Time frame: Intraoperative period (T0, T2, T5)]
- Dynamic Lung Compliance (Cdyn) [Time frame: Intraoperative period (all time points)]
- Peak Airway Pressure (Ppeak) [Time frame: Intraoperative period (all time points)]
Eligibility criteria
Inclusion criteria
- 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
Exclusion criteria
- 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
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- Randomized
- Model
- Parallel assignment
- Masking
- Open label
- Primary purpose
- Treatment
Study locations
Center list to be confirmed — check the primary protocol.
Identifiers
NCT: NCT07545733 · REŞIT-PEEP-2026