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General anesthesia


General anesthesia brings on a sleep-like state with the use of a combination of medicines. The medicines, known as anesthetics, are given before and during surgery or other medical procedures. General anesthesia usually uses a combination of intravenous medicines and inhaled gasses.

You'll feel as though you're asleep. But general anesthesia does more than put you to sleep. You don't feel pain when you're under general anesthesia. This is because your brain doesn't respond to pain signals or reflexes.

An anesthesiologist is a doctor who specializes in anesthesia. In many hospitals, an anesthesiologist and a certified registered nurse anesthetist (CRNA) work together as a team during your procedure. While you're under anesthesia, the anesthesia team monitors you, watches your body's vital functions, manages your breathing and treats pain related to the procedure.

Why it's done

Your anesthesiologist, together with your surgeon or another specialist, will recommend the best anesthesia option for you. The form of anesthesia is chosen based on the type of surgery you're having, your overall health and your preferences.

Your team may recommend general anesthesia for certain procedures. These include procedures that may:

  • Take a long time.
  • Require the use of muscle relaxants.
  • Result in significant bleeding.
  • Significantly change your breathing, blood pressure or heart rate.

Other forms of anesthesia may be recommended depending on your procedure. Spinal anesthesia may be recommended for surgery below your waist such as a cesarean section or hip replacement. Regional anesthesia may be recommended for surgery on a specific part of the body such as a hand or foot. Local anesthesia may be appropriate for minor procedures that involve a small area such as a biopsy. While these forms of anesthesia are commonly combined with sedation during the procedure, they may not be appropriate for more-involved procedures.


General anesthesia is very safe. Most people don't have serious problems from general anesthesia. This is true even for people with significant health conditions.

Your risk of complications is more closely related to the type of procedure you're undergoing and your general physical health.

Older adults or those with serious medical problems are at increased risk of confusion after surgery. They're also at higher risk of pneumonia, stroke or a heart attack after surgery. This is particularly true if they're undergoing more-extensive procedures.

Conditions that can increase your risk of complications during surgery include:

  • Smoking.
  • Sleep apnea.
  • Obesity.
  • High blood pressure.
  • Diabetes.
  • Stroke.
  • Seizures.
  • Other medical conditions involving the heart, lungs, kidneys or liver.
  • Medicines that can increase bleeding.
  • Heavy alcohol or drug use.
  • Allergies to medicines.
  • Previous adverse reactions to anesthesia.

Anesthesia awareness

During procedures in which someone only receives sedation, it's expected that the person will be relaxed and comfortable. The person won't necessarily be asleep or unaware. It's common that someone who's sedated may be aware for part or all of the procedure.

Although very rare, a person may be partially awake during general anesthesia. Estimates vary, but about 1 or 2 people in every 1,000 may experience unintended intraoperative awareness. It is even rarer to experience pain, but this can occur as well.

This is so rare that it's hard to understand why it happens. Most cases of unintended intraoperative awareness occur during urgent or emergency surgeries. Or they occur during unexpected emergencies in routine surgeries. When it happens, a person may experience stress or anxiety. For some people, the experience can result in long-term psychological problems similar to post-traumatic stress disorder.

How you prepare

In the days or weeks before your procedure, adopt healthy lifestyle habits. You can do this by increasing your activity level, eating a healthy diet, getting plenty of sleep and stopping tobacco use. Better health before surgery can help improve your recovery after anesthesia and surgery.

Be sure to let your health care provider know about all the medicines you take. This includes prescription medicines as well as medicines, vitamins and supplements you can get without a prescription.

Some medicines are safe or even encouraged to continue throughout your surgery. But some medicines must be stopped for a day or several days before surgery. Your health care provider or surgeon can tell you which medicines to take and which medicines to stop taking before surgery.

You'll be given instructions about when to stop eating and drinking. Rules about eating and drinking are set to allow enough time for food and liquid to empty from your stomach before your procedure. Sedation and anesthesia relax the muscles in your digestive tract. This reduces your body's usual protective reflexes that help prevent food and acid from passing from your stomach into your lungs. For your safety, it's important to follow these instructions. If you don't follow instructions about when to stop eating and drinking before surgery, your procedure may be delayed or canceled.

If you have sleep apnea, discuss your condition with your surgeon and anesthesiologist. The anesthesiologist or CRNA will need to carefully check your breathing during and after your surgery. If you wear a device at night for treatment of sleep apnea, bring your device with you to the procedure.

What you can expect

Before the procedure

Before you have anesthesia, your anesthesiologist will talk with you and may ask questions about:

  • Your health history.
  • Your prescription medicines, along with any nonprescription medicines and herbal supplements.
  • Any allergies to medicines you have.
  • Your past experiences with anesthesia.
  • The last time you ate or drank anything.

This will help your anesthesia team choose the form of anesthesia that will be the safest for you.

During the procedure

Your anesthesiologist or CRNA usually delivers the anesthesia medicines through an intravenous line in your arm. Sometimes you may be given a gas that you breathe from a mask. Children may prefer to go to sleep with a mask.

Once you're asleep, the anesthesiologist or CRNA may insert a flexible, plastic breathing tube into your mouth and down your windpipe. The tube ensures that you get enough oxygen. It also protects your lungs from oral secretions or other fluids such as stomach fluids. The breathing tube is removed at the end of the procedure as you start to awaken.

Someone from the anesthesia care team monitors you while you sleep. This anesthesia team member adjusts your medicines, breathing, temperature, fluids and blood pressure as needed. Any issues that occur during the surgery are corrected with medicine and fluids. Rarely, blood transfusions are needed.

After the procedure

When the surgery is complete, the anesthesiologist or CRNA stops the anesthetic medicines. You'll slowly wake either in the operating room or the recovery room. You'll probably feel groggy and a little confused when you first awaken.

You may experience side effects such as:

  • Sleepiness.
  • Nausea or vomiting.
  • Dry mouth.
  • Sore throat.
  • Mild hoarseness.
  • Shivering.
  • Itching.
  • Blurry vision.
  • Dizziness.
  • Muscle aches.

You also may experience other side effects after you awaken from anesthesia, such as pain. Your anesthesia care team will ask you about your pain and other side effects. Side effects depend on your condition and the type of surgery. Your health care provider may give you additional medicines after your procedure to reduce pain and nausea.

Content Last Updated: 16-Feb-2023
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