Lumbar Disc Herniation, Lumbar Spine Stenosis, Postoperative Complications, Ventilator-Induced Lung Injury
Conditions
Brief 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.
Interventions
PROCEDUREDynamic 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.
PROCEDUREStandard 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.
Sponsors
Ankara City Hospital Bilkent
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
OTHER
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Modified Lung Ultrasound Score | 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). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Incidence postoperative pulmonary complications(PPC) | 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 |
| Intraoperative Dynamic Compliance (Cdyn) | intraoperative | Mean dynamic respiratory compliance measured during the intraoperative period. Unit of Measure: mL/cmH2O |
| Intraoperative Plateau Pressure (Pplat) | intraoperative | Mean airway plateau pressure measured during the intraoperative period. Unit of Measure: cmH2O |
| Intraoperative Driving Pressure (ΔP) | intraoperative | Mean airway Driving Pressure measured during the intraoperative period. Unit of Measure: cmH2O |
| Intraoperative Peak Pressure (Ppeak) | intraoperative | Mean airway Peak Pressure measured during the intraoperative period. Unit of Measure: cmH2O |
| Mean arterial pressure(MAP) | Baseline,intraoperative,1st hour postoperatively. | Mean arterial pressure(MAP) |
| Heart Rate | Baseline,intraoperative,1st hour postoperatively. | Heart Rate |
| Length of stay | From date of surgery until date of hospital discharge | Hospitalization duration |
| Partial pressure of oxygen | Baseline, intraoperative,1st hour postoperatively. | arterial blood oxygen partial pressure |
| SPO2 | Baseline,intraoperative,1st hour postoperatively. | Measurement of non invasive oxygen saturation |
Countries
Turkey (Türkiye)
Outcome results
None listed