Randomized Controlled Trial:High-flow Oxygen Therapy and Tracheal Intubation for Laryngeal Microsurgery

Over time, the accumulation of carbon dioxide reduces the pressure gradient for the alveolar transfer of oxygen, limiting the successful duration of apneic oxygenation. NIRS (Near-Infrared Spectroscopy) technology is able to provide an estimate of the regional balance between demand and supply of brain oxygen. The primary hypothesis of this study is that although high-flow oxygen therapy may be associated with transiently higher PaCO2 values than those found in patients undergoing tracheal intubation and traditional mechanical ventilation, due to the brevity of this phenomenon the variations in the average values of frontal cerebral tissue oxygen saturation are expected to be of similar magnitude between the two groups. Secondary objectives will be the comparison of the success rate of high-flow oxygen therapy compared to traditional airway management by mechanical ventilation. The success rate will be defined as blood pressure of carbon dioxide (PaCO2) \= 94% throughout the procedure, in the absence of adverse events (haemodynamic alteration, dyspnea, discomfort). The data will be analyzed according to an intention-to-treat principle. Continuous variables with repeated measurements will be compared with a mixed-effect linear regression model. Normality of distribution will be verified with the Shapiro-Wilk test. Continuous variables will be compared with Student t- or Mann-Whitney test; categorical variables with the Chi-square test.