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General anesthesia
By Mayo Clinic staffMayo Clinic Health Manager
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Definition
General anesthesia is a treatment that puts you to sleep during medical procedures, so you don't feel or remember anything that happens. General anesthesia is commonly produced by intravenous drugs or inhaled gasses.
The "sleep" you experience under general anesthesia is different from regular sleep. The anesthetized brain doesn't form memories or respond to pain signals.
Why it's done
Other forms of anesthesia may provide light sedation or use injections to numb a region of your body selectively. Your doctor may recommend general anesthesia for procedures that:
- Take a long time
- Affect your breathing, such as chest or upper abdomen surgery
- Require you to be in an uncomfortable position during the surgery
Risks
Most healthy people don't have any problems with general anesthesia. However, the following factors can increase your risk of complications:
- Medical conditions involving your heart, lungs or kidneys
- Medications, such as aspirin, that can increase bleeding
- Smoking, which increases the likelihood of breathing problems
- Alcohol use, which may predispose you to liver damage
- Family history of adverse reactions to anesthesia
- Food or drug allergies
The following complications are rare and occur more frequently in people who have medical problems, or who are elderly:
- Temporary mental confusion
- Lung infections
- Stroke
- Heart attack
- Death
Anesthesia awareness
Estimates vary, but about one or two people in every 1,000 cases may wake up briefly during general anesthesia. In most cases, the person is simply aware of his or her surroundings and doesn't feel any pain. However, some people experience excruciating pain and develop long-term psychological problems.
The following factors appear to make this phenomenon — called anesthesia awareness or unintended intraoperative awareness — more likely:
- Long-term use of anticonvulsants, opiates, tranquilizers or cocaine
- Heart or lung problems
- Daily alcohol use
How you prepare
General anesthesia blunts your body's natural inclination to keep food in your stomach and out of your lungs. That's why it's important to follow your doctor's instructions about when to stop eating and drinking prior to surgery. In most cases, you should start fasting about eight hours before your procedure.
Your doctor may tell you to take certain medications with a small sip of water during your fasting time. You may need to avoid some medications, such as blood thinners like aspirin, for at least a week before your procedure. Some vitamins and herbal remedies also keep your blood from clotting normally, so you should discuss the types of dietary supplements you take with your doctor.
What you can expect
Before general anesthesia
Before you receive general anesthesia, a medical professional specially trained to deliver anesthesia will talk with you and may ask questions about:
- Your health history
- Prescription medications, over-the-counter medications and herbal supplements you take
- Allergies
- Your past experiences with anesthesia
The information you provide will help the anesthesia specialist choose the drugs that will work best and be safest for you.
During general anesthesia
In most cases, the anesthesia is started with medication delivered through an intravenous line in your arm, but sometimes it can be started with a gas that you breathe from a mask. For example, children who are afraid of needles may prefer to go to sleep with a mask. Once you are asleep, a tube may be inserted into your mouth and down your windpipe to ensure you get enough oxygen and to protect your lungs from secretions.
A member of the anesthesia care team stays with you constantly during your procedure, monitoring you closely and adjusting your medications, breathing, temperature, fluids and blood pressure as needed.
After general anesthesia
When the surgery is complete, the anesthesia drugs are discontinued and you gradually wake up either in the operating room or the recovery room.You'll probably feel groggy and a little confused when you first wake up. Other common side effects include:
- Nausea
- Vomiting
- Dry mouth
- Sore throat
- Shivering
- Sleepiness
