Laryngotracheal surgery often requires a small diameter endotracheal tube to oxygenate patients under general anesthesia. Oxygenation is often only possible with high-frequency jet ventilators due to the use of small diameter and high resistance airway cannulas. Flow controlled ventilation is a new ventilation modality capable for ventilation through a small diameter endotracheal tube (Tritube) with an active expiratory phase and the possibility of controlled carbon dioxide elimination during mechanical ventilation. The aim of the present trial is to characterize perioperative changes in lung volume, ventilation inhomogeneity and respiratory mechanics in patients undergo upper airway surgery under general anesthesia with either flow controlled or high-frequency jet ventilation.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
50
Patients undergoing general anesthesia and mechanical ventilation.
Mechanical ventilation is assured by Flow-controlled ventilation mode.
Mechanical ventilation is assured by High frequency jet ventilation mode.
Geneva University Hospitals
Geneva, Switzerland
RECRUITINGAlterations in the functional residual capacity (FRC)
FRC measured by the nitrogen multiple breath washout technique that will be applied before and after general anesthesia
Time frame: Right before general anesthesia and approximately 1 hour after general anesthesia or before discharge from post anesthesia care unit
Alterations in the Lung clearance index (LCI)
LCI measured by the nitrogen multiple breath washout technique that will be applied before and after general anesthesia
Time frame: Right before general anesthesia and approximately 1 hour after general anesthesia or before discharge from post anesthesia care unit
Alterations in the respiratory resistance assessed by the forced oscillation technique (FOT)
Respiratory mechanics will be measured by the forced oscillation technique (FOT) to evaluate respiratory resistance (R).
Time frame: Right before general anesthesia and approximately 1 hour after general anesthesia or before discharge from post anesthesia care unit
Alterations in the respiratory reactance assessed by the forced oscillation technique (FOT)
Respiratory mechanics will be measured by the forced oscillation technique (FOT) to evaluate respiratory reactance (X).
Time frame: Right before general anesthesia and approximately 1 hour after general anesthesia or before discharge from post anesthesia care unit
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