General anesthesia is a combination of medicines that causes you to become unconscious. You inhale or receive the medicines through a needle in a vein. This affects your whole body. Under anesthesia, you should be completely unaware and not feel pain during the surgery or procedure. General anesthesia also causes you to forget things for a short time and relaxes your muscles.
General anesthesia suppresses many of your body's normal automatic functions. This includes those that control breathing, heartbeat, circulation of the blood (such as blood pressure), and movements of the digestive system. It also includes throat reflexes such as swallowing, coughing, or gagging that prevent foreign material from being inhaled into your lungs (aspiration).
Risks and side effects
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.
You will be instructed on when to stop eating or drinking before anesthesia so that your stomach is empty. This will help to prevent food from being inhaled (aspirated) into your lungs. Be sure to carefully follow the directions you are given. The breathing tube inserted during general anesthesia can also prevent stomach contents from entering your lungs.
After surgery using general anesthesia, a common side effect is nausea and vomiting. Most of the time, this can be treated and doesn't last long. Also, some people have a sore throat or hoarseness from the breathing tube inserted after the person is unconscious. Inserting the breathing tube can sometimes cause damage to a person's mouth or teeth, but this is uncommon.
Rare but serious risks of general anesthesia include:
- Heart attack, heart failure, or stroke.
- Increases or decreases in blood pressure.
- Pneumonia or other breathing disorders.
- Reactions to medicines used in the anesthesia.
- Muscle damage and a rapid increase in body temperature.
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. Anesthesia specialists devote careful attention and use many methods to prevent this.
When beginning to wake up from general anesthesia, some people experience some confusion, disorientation, or difficulty thinking clearly. This is normal. It may take some time before the effects of the anesthesia are completely gone. It's important not to do anything for 24 hours that requires attention to detail. This includes going to work or school, making important decisions, and signing any legal documents.
For your safety, do not drive or operate any machinery that could be dangerous until the medicine wears off and you can think clearly and react easily.
Current as of: June 23, 2021
Author: Healthwise Staff
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
John M. Freedman MD - Anesthesiology
Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.
HealthLinkBC Files are easy-to-understand fact sheets on a range of public health and safety topics including disease prevention and immunizations.
Find Services and Resources
If you are looking for health services in your community, you can use the HealthLinkBC Directory to find hospitals, clinics, and other resources.