Topic summary
General anesthesia
Extracted from the Wikipedia article General anaesthesia.
Maintenance
The duration of action of intravenous induction agents is generally 5 to 10 minutes, after which spontaneous recovery of consciousness will occur. In order to prolong unconsciousness for the duration of surgery, anaesthesia must be maintained. This is achieved by allowing the patient to breathe a carefully controlled mixture of oxygen and a volatile anaesthetic agent, or by administering intravenous medication (usually propofol). Inhaled anaesthetic agents are also frequently supplemented by intravenous analgesic agents, such as opioids (usually fentanyl or a fentanyl derivative) and sedatives (usually propofol or midazolam). Propofol can be used for total intravenous anaesthesia (TIVA), therefore supplementation by inhalation agents is not required. General anesthesia is usually considered safe; however, there are reported cases of patients with distortion of taste and/or smell due to local anesthetics, stroke, nerve damage, or as a side effect of general anesthesia.