General anesthesia is a combination of medicines that you inhale or receive through a needle in a vein to cause you to become unconscious. It affects your whole body. Under anesthesia, you should be completely unaware and not feel pain during the surgery or procedure. General anesthesia also causes forgetfulness (amnesia) and relaxation of the muscles throughout your body.
General anesthesia suppresses many of your body's normal automatic functions, such as those that control breathing, heartbeat, circulation of the blood (such as blood pressure), movements of the digestive system, and throat reflexes such as swallowing, coughing, or gagging that prevent foreign material from being inhaled into your lungs (aspiration).
Because these functions are suppressed, an anesthesiologist must carefully keep a balance of medicines while watching your heart, breathing, blood pressure, and other vital functions. An endotracheal (ET) tube or a laryngeal mask airway device is usually used to give you an inhaled anesthetic and oxygen and to control and assist your breathing.
General anesthesia is commonly begun (induced) with intravenous (IV) anesthetics. But inhaled anesthetics also may be used. After you are unconscious, anesthesia may be maintained with an inhaled anesthetic alone, with a combination of intravenous anesthetics, or a combination of inhaled and intravenous anesthetics.
As you begin to awaken from general anesthesia, you may 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.
Risks and 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.
You will be instructed on when to stop eating or drinking before anesthesia so that your stomach is empty. The amount of time depends on the procedure. 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. Anesthesiologists devote careful attention and use many methods to prevent this.
Primary Medical Reviewer Adam Husney, MD - Family Medicine
Brian O'Brien, MD, FRCPC - Internal Medicine
Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer John M. Freedman, MD - Anesthesiology
Current as ofJune 12, 2017
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