Dynamic Compliance-Guided Ventilation in Lumbar Surgery

May 22, 2026 updated by: Burak NALBANT, Ankara City Hospital Bilkent

Impact of Dynamic Compliance-guided Ventilation on Postoperative Pulmonary Function in Lumbar Stabilization Surgery:A Prospective Study

Postoperative pulmonary complications are a frequent cause of morbidity following lumbar stabilization surgery. Conventional ventilation strategies may not adequately reflect intraoperative changes in respiratory mechanics, potentially leading to impaired postoperative pulmonary function. Dynamic compliance-guided ventilation provides a real-time, individualized approach by adjusting ventilatory parameters according to lung compliance.

This prospective randomized controlled study aims to evaluate the effects of dynamic compliance-guided ventilation compared with standard ventilation strategies on postoperative pulmonary function in patients undergoing lumbar stabilization surgery. Eligible patients will be randomly assigned to either the compliance-guided group or the conventional ventilation group.

In this study, the investigators aim to prospectively compare ventilation with the dynamic compliance (Cdyn) approach-one of the lung-protective ventilation strategies-with conventional ventilation methods in patients undergoing surgery in the prone position. The primary outcome will be evaluated using a modified lung ultrasound scoring system based on the most severely affected regions of aeration loss. Secondary objectives include the assessment of intraoperative hemodynamics, respiratory mechanics, and the effects on postoperative pulmonary function.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

72

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients who will undergo lumbar stabilization in the prone position

Exclusion Criteria:

  • Patients with ASA classification IV or higher
  • Patients with obesity (BMI>30) or cachexia (BMI<18)
  • Allergy to standard medications used during general anesthesia
  • Contraindications to PEEP (high intracranial pressure, bronchopleural fistula, hypovolemic shock, right heart failure)
  • Previous lung surgery (any)
  • Known serious heart disease defined as New York Heart Association class III or higher
  • Patients with severe asthma and COPD
  • Acute myocardial infarction within the last 12 months before surgery
  • Neuromuscular disease

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Dynamic Compliance Guided Ventilation
Patients receive intraoperative ventilation adjusted according to real time dynamic compliance monitoring
Procedure: Dynamic Compliance Guided Ventilation
After intubation and prone positioning, both groups will undergo the same initial recruitment maneuver as described above. In the dynamic compliance-guided group, positive end expiratory pressure(PEEP) will then be titrated according to dynamic compliance (Cdyn = VT / [Ppeak - PEEP])(Ppeak: Peak airway pressure)(VT:Tidal volume). Tidal volume will be set at 7 ml/kg, respiratory rate 12/min, and positive end expiratory pressure(PEEP) reduced stepwise from 20 cmH₂O to 5 cmH₂O in increments of 2 cmH₂O. Each positive end expiratory pressure(PEEP) level (19, 17, 15, 13, 11, 9, 7, 5 cmH₂O) will be maintained for 10 respiratory cycles, with Cdyn measured at the end of each level. The positive end expiratory pressure(PEEP) corresponding to the highest dynamic compliance will be selected and maintained throughout the surgery.In both groups, a 30% t-pause will be applied throughout the operation after intubation. Patients will be ventilated in volume-controlled ventilation (VCV) mode.
Active Comparator: Standart Ventilation
Patients receive intraoperative ventilation based on conventional standart settings without dynamic compliance adjustment
Procedure: Standard Ventilation
After intubation, both groups will initially receive conventional ventilation in volume-controlled mode with a tidal volume of 7 ml/kg (predicted body weight), positive end expiratory pressure(PEEP) of 5 cmH₂O, and an inspiratory-to-expiratory ratio of 1:2. Respiratory rate will be adjusted to maintain end-tidal CO₂ between 35-45 mmHg. Following prone positioning, a recruitment maneuver will be performed using pressure-controlled ventilation, gradually increasing positive end expiratory pressure(PEEP) from 5 to 20 cmH₂O and holding for 20 seconds. After recruitment, the standard ventilation group will continue with the initial ventilator settings until the end of the surgery. Patients will be ventilated in volume-controlled ventilation (VCV) mode.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Modified Lung Ultrasound Score
Time Frame: baseline, postoperative 1th hour, postoperative 24th hour
The assessment will be performed using the Modified Lung Ultrasound Scoring system. The scale ranges from a minimum of 0 to a maximum of 36 points. A score of 0 indicates normal aeration in all zones, while a score of 36 represents the worst possible aeration loss. Higher scores indicate a worse outcome (increased lung aeration loss/atelectasis).
baseline, postoperative 1th hour, postoperative 24th hour

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence postoperative pulmonary complications(PPC)
Time Frame: postoperative first 7 days

Number of participants with at least one postoperative pulmonary complication (including atelectasis, pneumonia, bronchospasm, hypoxemia, or reintubation) within the first 7 days after surgery.

Percentage of participants
postoperative first 7 days
Intraoperative Dynamic Compliance (Cdyn)
Time Frame: intraoperative
Mean dynamic respiratory compliance measured during the intraoperative period. Unit of Measure: mL/cmH2O
intraoperative
Intraoperative Plateau Pressure (Pplat)
Time Frame: intraoperative
Mean airway plateau pressure measured during the intraoperative period. Unit of Measure: cmH2O
intraoperative
Intraoperative Driving Pressure (ΔP)
Time Frame: intraoperative
Mean airway Driving Pressure measured during the intraoperative period. Unit of Measure: cmH2O
intraoperative
Intraoperative Peak Pressure (Ppeak)
Time Frame: intraoperative
Mean airway Peak Pressure measured during the intraoperative period. Unit of Measure: cmH2O
intraoperative
Mean arterial pressure(MAP)
Time Frame: Baseline,intraoperative,1st hour postoperatively.
Mean arterial pressure(MAP)
Baseline,intraoperative,1st hour postoperatively.
Heart Rate
Time Frame: Baseline,intraoperative,1st hour postoperatively.
Heart Rate
Baseline,intraoperative,1st hour postoperatively.
Length of stay
Time Frame: From date of surgery until date of hospital discharge
Hospitalization duration
From date of surgery until date of hospital discharge
Partial pressure of oxygen
Time Frame: Baseline, intraoperative,1st hour postoperatively.
arterial blood oxygen partial pressure
Baseline, intraoperative,1st hour postoperatively.
SPO2
Time Frame: Baseline,intraoperative,1st hour postoperatively.
Measurement of non invasive oxygen saturation
Baseline,intraoperative,1st hour postoperatively.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Ankara City Hospital Bilkent

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

January 22, 2026

Primary Completion (Actual)

May 20, 2026

Study Completion (Estimated)

June 1, 2026

Study Registration Dates

First Submitted

December 29, 2025

First Submitted That Met QC Criteria

January 9, 2026

First Posted (Actual)

January 20, 2026

Study Record Updates

Last Update Posted (Actual)

May 26, 2026

Last Update Submitted That Met QC Criteria

May 22, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1-25-1645

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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