Inhalational anesthesia is a method of using anesthetic drugs through the respiratory tract to put the patient into a state of unconsciousness but still maintain vital functions before surgery. Inhalational anesthesia is indicated in some surgeries or pain relief in some cases.

Recovery from anesthesia is one of the stages of anesthesia, in the recovery phase the patient may experience some side effects of the drug and post-operative effects. Therefore, in this recovery phase, it is necessary to pay attention to monitoring to minimize and promptly overcome the complications caused.

Preoxygenation before induction of anesthesia and before intubation is a method used to prevent hypoxemia during apnea. Because of the unpredictable difficulties of ventilation and intubation, preoxygenation before induction of anesthesia is necessary in all patients.