Flow-Controlled Versus Volume-Controlled Ventilation During Balloon Dilatation Under Direct Laryngoscopy

Ankara Etlik City Hospital40 enrolled

Overview

This prospective trial aims to compare the effects of flow-controlled ventilation (FCV) and volume-controlled ventilation (VCV) on airway pressures and oxygenation in adult patients undergoing balloon dilatation under direct laryngoscopy. Airway procedures performed under general anesthesia are associated with unique respiratory mechanics and limited ventilation conditions, making the choice of an optimal ventilation strategy particularly important. Adult patients aged 18-65 years with American Society of Anesthesiologists (ASA) physical status I-III will be allocated to receive either FCV or VCV during surgery. Ventilatory parameters, airway pressures, pulmonary compliance, and arterial blood gas values will be recorded at predefined intraoperative time points. The primary outcome is the PaO₂ measured 20 minutes under an FiO₂ of 0.8-1.0 after starting the ventilation under general anesthesia, reflecting early intraoperative oxygenation under stable conditions. By providing comparative data on respiratory mechanics and oxygenation, this study aims to contribute to the identification of lung-protective ventilation strategies in patients undergoing balloon dilatation under direct laryngoscopy.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

Conditions

Airway Stenosis Upper Airway Obstruction

Interventions

FCV GroupPROCEDURE

Patients allocated to the FCV group will receive mechanical ventilation using a flow-controlled ventilation mode throughout the surgical procedure performed under general anesthesia. Ventilation will be managed according to routine clinical practice, with standardized anesthetic induction and monitoring. Ventilatory parameters, airway pressures, pulmonary compliance, and arterial blood gas values will be recorded at predefined intraoperative time points, including after starting the ventilation under general anesthesia and 20 minutes after intubation. This group aims to evaluate the effects of FCV on airway pressures and early intraoperative oxygenation during balloon dilatation performed under direct laryngoscopy.

VCV GroupPROCEDURE

Patients allocated to the VCV group will receive mechanical ventilation using a conventional volume-controlled ventilation mode throughout the surgical procedure under general anesthesia. Anesthetic management and monitoring will follow standard clinical protocols identical to those applied in the FCV group. Ventilatory parameters, airway pressures, pulmonary compliance, and arterial blood gas measurements will be recorded at the same predefined intraoperative time points, including after starting the ventilation under general anesthesia and 20 minutes after intubation. This group serves as the comparator arm to assess the effects of volume-controlled ventilation on airway pressures and oxygenation during balloon dilatation under direct laryngoscopy.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Age between 18 and 65 years * ASA physical status I-III 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

Outcomes

Primary Outcomes

The PaO₂ measured 20 minutes after intubation.

The primary outcome measure will be the PaO₂ derived from arterial blood gas analysis at 20 minutes after intubation.

Time frame: 20 minutes after intubation in the intraoperative period

Secondary Outcomes

The PaO₂ measured during perioperative period

The PaO₂ values will be measured and recorded using arterial blood gas analysis.

Time frame: At the initiation of mechanical ventilation following intubation and at the first postoperative hour after extubation

Peak airway pressure (Ppeak) values during perioperative period.

Ppeak will be measured and recorded.

Time frame: At the initiation of mechanical ventilation following intubation and 20 minutes after intubation

Plateau airway pressure (Pplateau) values during perioperative period

Pplateau will be measured and recorded.