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
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
anesthesia specialist 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.
People are instructed not to eat or
drink anything for up to 8 hours before anesthesia so that the
stomach is empty. The amount of time depends on the procedure. This will help to prevent food from being inhaled (aspirated) into the lungs.
The breathing tube inserted during general anesthesia can also prevent stomach contents from entering the
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
Increases or decreases in blood pressure.
Pneumonia or other breathing disorders.
Difficulty placing a breathing tube.
Reactions to medicines used in the
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
How this information was developed to help you make better health decisions.