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.
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.
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.
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.
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.
