Flow-Controlled Versus Volume-Controlled Ventilation in Lumbar Disc Herniation Surgery

Comparison of Flow-Controlled and Volume-Controlled Ventilation During Lumbar Disc Herniation Surgery: A Prospective Randomized Trial

This prospective randomized trial aims to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on intraoperative airway pressures and oxygenation in patients undergoing lumbar disc herniation surgery under general anesthesia.

Adult patients aged 18-65 years, with ASA physical status I-III and a body mass index of 18-30 kg/m², will be allocated to receive either FCV or VCV during routine intraoperative mechanical ventilation. Ventilatory parameters, including peak airway pressure, plateau pressure, pulmonary compliance, EtCO₂, SpO₂, and arterial blood gas variables, will be recorded at predefined time points after intubation.

The primary endpoint is the PaO₂ value measured after 20 minutes in the prone position.

By comparing respiratory mechanics and oxygenation between the two ventilation modes, this study aims to contribute to the optimization of intraoperative ventilatory management in lumbar disc herniation surgery.

Inclusion Criteria:

• Age between 18 and 65 years
• ASA physical status I-III
• Body Mass Index between 18 and 30 kg/m²

Exclusion Criteria:

• Age < 18 years or > 65 years
• Known or previously diagnosed pulmonary disease
• Patients with severe preoperative pulmonary function impairment (e.g., FEV₁ < 50% predicted, severe restrictive or obstructive pathology)
• Patients with markedly altered lung anatomy or function due to prior major thoracic surgery
• Patients who were dependent on supplemental oxygen therapy in the preoperative period
• ASA physical status IV or higher
• Refusal or inability to provide informed consent