Whenever you have surgery, anesthesia helps you get through the procedure without pain. While anesthesia acts mostly during the operation, some effects persist afterward. The type of effects depends largely on whether you are fully asleep, as in general anesthesia, or you receive regional or local anesthesia. Nausea, vomiting and sleepiness are quite common after general anesthesia. For all types of anesthesia, most effects resolve within 24 hours after surgery.
Temporary Effects After General Anesthesia
General anesthesia can produce many effects that are most prominent in the first few hours after awakening. They typically disappear within 24 hours, as the anesthesia drugs leave the body. If symptoms persist after this, they are usually due to other factors, such as painkillers or the after-effects of surgery itself. Common temporary effects include sleepiness, dizziness, difficulty urinating, impaired thinking, nausea and vomiting. Difficulty urinating may require temporary insertion of a tube into the bladder. Several medications can relieve nausea and vomiting.
Short-Term Effects After General Anesthesia
Some effects can persist a few days after general anesthesia. Mild sore throat and hoarseness are possible. They are caused by the breathing tube often used during anesthesia, breathing in dry air and anesthesia gases, or being required to not eat or drink before surgery. Succinylcholine, an anesthesia muscle relaxant, may produce short-term generalized muscle pain.
Confusion -- known as postoperative delirium -- is another possible short-term effect. It is more common in older individuals, especially after major surgery. Anesthesia may play a role in the development of postoperative delirium, but other factors likely also contribute, including painkillers, the stress of surgery or being in the hospital.
Long-Term Effects After General Anesthesia
Long-term effects from general anesthesia are unlikely. A possible exception is postoperative cognitive dysfunction -- persistently reduced memory and thinking ability. The impairment may be subtle, usually resolves within 3 to 6 months, and is more common in older people and after major surgery. Although anesthesia has been suggested as a factor contributing to postoperative cognitive dysfunction, its role is uncertain. A February 2014 review article in "Current Opinion in Anaesthesiology" indicated that the main cause is brain inflammation due to surgery itself.
Effects After Regional Anesthesia
During regional anesthesia, local anesthetic medication is injected at a specific location, producing numbness and muscle weakness in a certain area. Spinal anesthesia, for example, involves medication injected into the fluid around the spinal cord to produce numbness and weakness in the lower part of the body. After surgery, numbness and weakness persist for a period of time that depends on the injection location and medication used. The longest regional anesthetics last up to 24 hours.
Spinal anesthesia may cause difficulty urinating in the first several hours after surgery until bladder sensation returns. It may also produce a headache that is present when sitting or standing but disappears when lying down. This headache may last several days. Sedative medications are often administered through a vein during regional anesthesia. They may cause symptoms similar to, though less severe than, the temporary general anesthesia effects.
Effects After Local Anesthesia
Local anesthesia involves injecting local anesthetic medication directly into the surgery area. It is used for minor operations in a small area. Numbness may persist for a few hours after surgery. Like regional anesthesia, sedation may be added and may produce similar mild symptoms after surgery.
Precautions and When to Seek Medical Attention
Because of temporary sleepiness, dizziness and impaired thinking after general anesthesia, do not drive, operate machinery, make important decisions or consume alcohol for the first 24 hours after surgery. If you had sedation with regional or local anesthesia, follow these same precautions.
Contact your surgeon if you have temporary or short-term effects of general anesthesia that are severe or prolonged. After regional anesthesia, seek immediate medical attention if you have significant pain, bleeding or other fluid leaking from the injection site, or if numbness or weakness persists beyond the time expected for your specific type of anesthesia.