Respiratory Effects of Flow-Controlled Ventilation and Jet Ventilation in Patients Undergoing Laryngotracheal Surgery

This study is a randomized, controlled, assessor blind, monocentric study. A new ventilation mode, called Flow Controlled Ventilation (FCV), has been suggested to minimize the amount of dissipated energy in the lungs and potentially could be protective during mechanical ventilation. FCV is unique in creating a stable gas flow into and also out of the patient's lungs to generate inspiration and expiration respectively. The FCV ventilation mode by its design allows the use of an ultrathin endotracheal tube with an inflatable cuff to secure the airways for ventilation. Therefore FCV offers several new surgical options for the treatment during laryngeal and tracheal surgery where the standard approach is usually the use of high-frequency jet ventilation (HFJV). The limitations of HFJV are however the lack of airway protection, limited monitoring of the respiratory variables and potential carbon dioxide (CO2) accumulation. Participants for this study will be recruited at the University Hospitals of Geneva, scheduled for laryngotracheal surgery under general anesthesia. A total of 50 patients will be enrolled and randomly assigned into 2 groups: Group FCV (Flow controlled ventilation) and Group HFJV (high-frequency jet ventilation). Measurements of functional residual capacity (FRC) and lung clearance index (LCI) will be performed in patients with a nitrogen multiple breath washout method, before and approximately 1 hour after surgery. Similarly, respiratory system resistance (R) and respiratory reactance (X) will be measured at the same time by using the Forced Oscillation Technique. Relevance: There are no studies that addressed the value of flow controlled ventilation in terms of lung function parameters (FRC and LCI) and lung mechanics (R, X) in comparison to high-frequency jet ventilation in patients undergoing upper airway surgery.