Comparison of Standard Versus Dynamic Compliance-Guided Individualized PEEP in Obese Patients Undergoing Spinal Surgery

A Prospective Interventional Study Comparing Standard and Dynamic Compliance-Guided Individualized Positive End-Expiratory Pressure on Intraoperative Oxygenation and Postoperative Pulmonary Complications in Obese Patients Undergoing Spinal Surgery

This study aims to compare standard positive end-expiratory pressure (PEEP) with dynamic compliance-guided individualized PEEP in obese patients undergoing elective spinal surgery under general anesthesia. Obesity and prone positioning during spinal surgery are associated with reduced lung compliance, atelectasis, and an increased risk of postoperative pulmonary complications.

Participants will be allocated to receive either a fixed standard PEEP or an individualized PEEP level determined according to intraoperative dynamic lung compliance. Intraoperative oxygenation, respiratory mechanics, arterial blood gas parameters, and hemodynamic variables will be assessed at predefined time points. Postoperative pulmonary complications within the first 24 hours after surgery will also be evaluated.

The study seeks to determine whether individualized PEEP titration based on dynamic compliance offers physiological or clinical advantages compared with a standard PEEP strategy in this patient population.

Study Overview

• Status: Completed
• Conditions: Obesity; Mechanical Ventilation; Postoperative Pulmonary Complications
• Intervention / Treatment: Device: Standard PEEP

• Study Type: Interventional
• Enrollment (Actual): 80
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Turkey (Türkiye)
  • Konya, Turkey (Türkiye), 42090
    • Konya City Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adult patients aged 18-65 years
• Body mass index (BMI) ≥30 kg/m²
• Scheduled for elective spinal surgery under general anesthesia
• Requirement for intraoperative mechanical ventilation
• American Society of Anesthesiologists (ASA) physical status II-III
• Provision of written informed consent

Exclusion Criteria:

• Pre-existing severe pulmonary disease (e.g., COPD GOLD stage III-IV, restrictive lung disease)
• Severe cardiac disease (e.g., heart failure with reduced ejection fraction, significant valvular disease)
• History of thoracic surgery affecting lung mechanics
• Pregnancy
• Emergency surgery
• Intraoperative need for deviation from the planned ventilation protocol

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Standard PEEP; Patients assigned to this arm receive a fixed positive end-expiratory pressure (PEEP) of 5 cmH₂O throughout the intraoperative period during mechanical ventilation.	Device: Standard PEEP; Application of a fixed positive end-expiratory pressure of 5 cmH₂O during intraoperative mechanical ventilation.
Experimental: Dynamic Compliance-Guided Individualized PEEP; Patients assigned to this arm receive individualized positive end-expiratory pressure (PEEP) titrated according to intraoperative dynamic lung compliance, with the aim of optimizing respiratory mechanics while avoiding overdistension.	Device: Standard PEEP; Application of a fixed positive end-expiratory pressure of 5 cmH₂O during intraoperative mechanical ventilation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intraoperative Oxygenation (PaO₂/FiO₂ Ratio)	The primary outcome is intraoperative oxygenation assessed by the arterial partial pressure of oxygen to fraction of inspired oxygen (PaO₂/FiO₂) ratio during mechanical ventilation.	From induction of anesthesia until the end of surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Dynamic Lung Compliance	Dynamic lung compliance (mL/cmH₂O) measured intraoperatively via ventilator respiratory mechanics monitoring.	From induction of anesthesia until the end of surgery
Static Lung Compliance	Static lung compliance (mL/cmH₂O) measured intraoperatively via ventilator plateau pressure analysis.	From induction of anesthesia until the end of surgery
Peak Airway Pressure	Peak inspiratory airway pressure (cmH₂O) measured intraoperatively using ventilator monitoring.	From induction of anesthesia until the end of surgery
Plateau Airway Pressure	Plateau airway pressure (cmH₂O) measured intraoperatively during mechanical ventilation.	From induction of anesthesia until the end of surgery

Collaborators and Investigators

• Sponsor: Konya City Hospital

Study record dates

Study Major Dates

• Study Start (Actual): February 2, 2025
• Primary Completion (Actual): December 12, 2025
• Study Completion (Actual): December 12, 2025

Study Registration Dates

• First Submitted: January 28, 2026
• First Submitted That Met QC Criteria: February 4, 2026
• First Posted (Actual): February 5, 2026

Study Record Updates

• Last Update Posted (Actual): February 5, 2026
• Last Update Submitted That Met QC Criteria: February 4, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity
• Other Study ID Numbers: NEU-2024-5206

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No