Anesthesia
Risks and Complications
Although all types of anesthesia involve some risk, major side effects and complications from anesthesia are uncommon. Your specific risks depend on your health, the type of anesthesia used, and your response to anesthesia.
Personal risk factors
Your age may be a risk factor. In general, the risks associated with anesthesia and surgery increase in older people.
Certain medical conditions, such as heart, circulation, or nervous system problems, increase your risk of complications from anesthesia.
Complications from local anesthesia
When used properly, local anesthetics are safe and have few major side effects. But in high doses local anesthetics can have toxic effects caused by being absorbed through the bloodstream into the rest of the body (systemic toxicity). This may significantly affect your breathing, heartbeat, blood pressure, and other body functions. Because of these potential toxic effects, equipment for emergency care must be immediately available when local anesthetics are used.
Complications from regional anesthesia
For regional anesthesia, an anesthetic is injected close to a nerve, a bundle of nerves, or the spinal cord. In rare cases, nerve damage can cause persistent numbness, weakness, or pain.
Regional anesthesia (regional nerve blocks, epidural and spinal anesthesia) also carries the risk of systemic toxicity if the anesthetic is absorbed through the bloodstream into the body. Other complications include heart or lung problems, and infection, swelling, or bruising (hematoma) at the injection site.
Spinal anesthesia medicine is injected into the fluid that surrounds the spinal cord (cerebrospinal fluid). The most common complication of spinal anesthesia is a headache caused by leaking of this fluid. With current techniques of giving spinal anesthesia, this occurs in about 1% to 2% of all people who have spinal anesthesia and is more common in younger people. A spinal headache may be treated quickly with a blood patch to prevent further complications. A blood patch involves injecting a small amount of the person's own blood into the area where the leak is most likely occurring to seal the hole and to increase pressure in the spinal canal and relieve the pull on the membranes surrounding the canal.
Complications from general anesthesia
Serious side effects of general anesthesia are uncommon in people who are otherwise healthy. But because general anesthesia affects the whole body, it is more likely to cause side effects than local or regional anesthesia. Fortunately, most side effects of general anesthesia are minor and can be easily managed.
General anesthesia suppresses the normal throat reflexes that prevent aspiration, such as swallowing, coughing, or gagging. Aspiration occurs when an object or liquid is inhaled into the respiratory tract (the windpipe or the lungs). To help prevent aspiration, an endotracheal (ET) tube may be inserted during general anesthesia. When an ET tube is in place, the lungs are protected so stomach contents cannot enter the lungs. Aspiration during anesthesia and surgery is very uncommon. To reduce this risk, people are usually instructed not to eat or drink anything for a specific number of hours before anesthesia so that the stomach is empty. Anesthesia specialists use many safety measures to minimize the risk of aspiration.
Insertion or removal of airways may cause respiratory problems such as coughing; gagging; or muscle spasms in the voice box, or larynx
(laryngospasm), or in the bronchial tubes in the lungs (bronchospasm). Insertion of airways also may cause an increase in blood pressure (hypertension) and heart rate (tachycardia). Other complications may include damage to teeth and lips, swelling in the larynx, sore throat, and hoarseness caused by injury or irritation of the larynx.
Other serious risks of general anesthesia include changes in blood pressure or heart rate or rhythm, heart attack, or stroke. Death or serious illness or injury due solely to anesthesia is rare and is usually also related to complications from the surgery. Death occurs in about 1 in 250,000 people receiving general anesthesia, although risks are greater for those people with serious medical conditions.1
Some people who are going to have general anesthesia express concern that they will not be completely unconscious but will "wake up" and have some awareness during the surgical procedure. But awareness during general anesthesia is very rare because anesthesia specialists devote careful attention and use many methods to prevent this.
Risks from reactions to anesthetic medicines
Some anesthetic medicines may cause allergic or other abnormal reactions in some people, but these are rare. If you suspect you may have such a problem, you should tell both your surgeon and anesthesia specialist well before your surgery. Testing will then be arranged as necessary.
A rare, potentially fatal condition called malignant hyperthermia (MH) may be triggered by some anesthetics. The anesthetics most commonly associated with malignant hyperthermia include the potent inhalation anesthetics and the muscle relaxant succinylcholine. For more information, see the listing for the Malignant Hyperthermia Association of the United States (MHAUS) in the Other Places to Get Help section of this topic.
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| Author: | Caroline Rea, RN, BS, MS | Last Updated: February 4, 2008 |
| Medical Review: | E. Gregory Thompson, MD - Internal Medicine John M. Freedman, MD - Anesthesiology | |
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| Topic Contents | |
| Topic Overview | |
| Frequently Asked Questions | |
| Preparing for Anesthesia | |
| Types of Anesthesia | |
| What Happens During Anesthesia | |
 | Risks and Complications |
| Recovering From Anesthesia | |
| Other Places To Get Help | |
| References | |
| Credits | |