General anesthesia is a combination of medicines that you inhale through a mask 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.
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
ET tube may be inserted during general
anesthesia. When the 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 certain 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 an ET tube or other airway device may cause respiratory problems
such as coughing or gagging. Insertion of an airway device 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.
vomiting are more likely with a lengthy procedure and also with certain types of procedures, such as eye or abdominal surgery. In most cases, nausea after anesthesia doesn't last long and can be treated with
medicines called antiemetics. Vomiting may be a serious problem if it causes pain and stress or affects surgical incisions.
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
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
September 30, 2011
Adam Husney, MD - Family Medicine & John M. Freedman, MD - Anesthesiology
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