In preparing for a medical procedure, the clinician chooses one or more drugs to achieve the types and degree of anesthesia characteristics appropriate for the type of procedure and the particular patient. The types of drugs used include general anesthetics, local anesthetics, hypnotics, sedatives, neuromuscular-blocking drugs, narcotics, and analgesics.
Risks during and following anesthesia are difficult to quantify, since many may be related to a variety of factors related to anesthesia itself, the nature of the procedure being performed and the patient’s medical health. Examples of major risks include death, heart attack and pulmonary embolism whereas minor risks can include postoperative nausea and vomiting and hospital readmission.
Of these factors, the person’s health prior to the procedure(stratified by the ASA physical status classification system) has the greatest bearing on the probability of a complication occurring. Patients typically wake within minutes of anesthesia being terminated and regain their senses within hours.