Dynamic Compliance-Guided Ventilation in Lumbar Surgery
Impact of Dynamic Compliance-guided Ventilation on Postoperative Pulmonary Function in Lumbar Stabilization Surgery:A Prospective Study
Ankara City Hospital Bilkent
71 participants
Jan 22, 2026
INTERVENTIONAL
Conditions
Summary
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.
Eligibility
Inclusion Criteria1
- Patients who will undergo lumbar stabilization in the prone position
Exclusion Criteria9
- 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
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Interventions
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.
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.
Locations(1)
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NCT07349719