High Flow Oxygen in Patients Undergoing Surgery Under General Anesthesia

Preoxygenation remains an important determinant of morbidity and mortality in anesthesia despite advances in mask ventilation and difficult intubation management. 1. The usual practice Preoxygenation prior to the injection of the anesthetic agents is the administration of pure oxygen to delay the occurrence of hypoxemia during the apnea phase and intubation maneuvers. It consists of applying a mask on the patient's face and allowing it to ventilate, ensuring a perfect seal of the device. The end of oxygen exhalation fraction is a good reflection of the alveolar oxygenation and a value of 95% corresponds to a "total" alveolar oxygenation. When this value is reached, the injection of the anesthetic agents (hypnotic, morphine and myorelaxant) leads to the loss of consciousness and apnea, which forces to continue the manual ventilation to the mask. Intubation is performed when the myorelaxation is complete. 2. Anesthetic induction "without the hands" The Optiflow Anesthesia (Fisher and Paykel Healthcare, Auckland, New Zealand) device provides heated, Humidified High-Flow Nasal Oxygen. The hypothesis of this study is that Humidified High-Flow Nasal Oxygen, should allow anesthetic induction without having to impose the patient the establishment of a facial mask for several minutes before anesthetic induction and the doctor anesthetist assisted ventilation with the mask before intubation.