Lower Inspiratory Oxygen Fraction for Preoxygenation

During the induction period of general anesthesia, surgical patients are inevitably experienced a short period of apnea for endotracheal intubation or other airway manipulation. In order to minimize the risks of hypoxemia during the establishment of artificial airway, pure oxygen (FiO2=100%) is commonly applied to the patients throughout the preoxygenation and induction period. However, high concentration of oxygen therapy has been shown to result in hyperoxemia and substantial oxygen exposure during perioperative period or critical care. There is currently no clinical evidence indicating that preoxygenation with a lower oxygen partial pressure (such as FiO2=60%) during the induction of anesthesia increases the incidence of hypoxemia or other complications. The findings of this proposed clinical study may provide fundamental evidence for the use of different oxygen concentrations in clinical anesthesia during the induction period, and determine the effects of inspired oxygen concentrations on the general postoperative outcomes during general anesthesia.