Comparison of Flow-Controlled Ventilation and Volume-Controlled Ventilation on Respiratory Mechanics During Suspension Laryngoscopy: A Prospective Observational Study

Suspension laryngoscopy is a shared-airway surgical procedure that requires optimal visualization of the operative field while maintaining adequate ventilation and oxygenation. Conventional ventilation strategies may be associated with increased airway pressures and limited surgical exposure due to the use of standard endotracheal tubes. Flow-controlled ventilation (FCV) is a ventilation mode characterized by constant inspiratory and expiratory flow, which may offer advantages in procedures requiring a narrow airway device.

This prospective, non-randomized, observational comparative study evaluates adult patients undergoing elective suspension laryngoscopy. The choice of ventilation strategy-flow-controlled ventilation or conventional volume-controlled ventilation-was based on the attending anesthesiologist's clinical preference, reflecting routine clinical practice. All patients provided written informed consent prior to participation.

In both groups, standardized anesthetic management was applied, and ventilation parameters were adjusted to maintain normocapnia and adequate oxygenation. Intraoperative respiratory mechanics, including airway pressures and lung compliance, were recorded at predefined intervals. Hemodynamic parameters were monitored throughout the procedure. Pulmonary function tests were performed preoperatively and postoperatively using a portable spirometry device. Perioperative complications were documented.

The primary objective of this study is to compare intraoperative respiratory mechanics between flow-controlled and volume-controlled ventilation during suspension laryngoscopy. Secondary objectives include the assessment of perioperative hemodynamic parameters, changes in pulmonary function, and procedure-related complications.