General Anesthesia

What Is General Anesthesia?

General anesthesia is medicine you get before some types of surgery to make you sleep and prevent you from feeling pain.

General Anesthesia Procedure

General anesthesia works by interrupting nerve signals in your brain and body. It prevents your brain from processing pain and from remembering what happened during your surgery.

A specially trained doctor, called an anesthesiologist, gives you general anesthesia and cares for you before, during, and after your surgery. A nurse anesthetist and other team members may also be involved in your care. 

Before your surgery, you'll get anesthesia through an IV line that goes into a vein in your arm or hand. You might also breathe in gas through a mask. You should fall asleep within a couple of minutes.

Once you're asleep, the doctor might put a tube through your mouth into your windpipe. This tube ensures that you get enough oxygen during surgery. The doctor will first give you medicine to relax the muscles in your throat. You won't feel anything when the tube is inserted.

During surgery, the anesthesia team will check these and other body functions:

Your medical team will use these measurements to adjust your medications or give you more fluids or blood if you need them. They will also make sure you stay asleep and pain-free for the whole procedure.

After surgery, the doctor will stop your anesthesia medicines. You'll go to a recovery room, where you'll slowly wake up. The doctors and nurses will make sure you aren’t in pain and that you don't have any problems from the surgery or the anesthesia.

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Stages of General Anesthesia

Before they had machines to track your vital signs during general anesthesia, doctors came up with a monitoring system to keep patients safe. They divided the system into four stages:

  • Stage 1: Induction. The earliest stage lasts from when you first take the medication until you go to sleep. You’re calm but able to talk for a while. Your breathing is slow but regular, and you lose the ability to feel pain.
  • Stage 2: Excitement or delirium. The second stage can be dangerous, so the anesthesiologist will want to get you through it as quickly as possible. You can have uncontrolled movements, fast heartbeat, and irregular breathing. You might vomit, which could make you choke or stop breathing.
  • Stage 3: Surgical anesthesia. At this stage, surgery can take place. Your eyes stop moving, your muscles completely relax, and you may stop breathing without the help of machines. The anesthesiologist will keep you at this stage until the procedure is over.
  • Stage 4: Overdose. If you get too much anesthesia, your brain will stop telling your heart and lungs to work. It’s rare with modern technology, but it can be fatal.

When Do You Get General Anesthesia?

The doctor might give you general anesthesia if your procedure:

  • Takes a few hours or more
  • Affects your breathing
  • Affects a large area of your body
  • Involves a major organ, like your heart or brain
  • Could make you lose a lot of blood

When Is General Anesthesia Not Needed?

You and your doctor may decide it isn’t the right choice for you if:

  • Your surgery is minor
  • The procedure affects a small part of your body (such as on your foot or face)

For these types of procedures, you might just need:

Local anesthesia. This prevents any pain in the small area of the surgery, but you stay awake.

Regional anesthesia. This numbs a larger area of your body, like your legs, but you also stay awake.

General Anesthesia Preparation

You'll meet with your doctor and anesthesiologist before the surgery. They'll go over your surgery so you know what to expect. The anesthesiologist will ask you:

  • What medical conditions you have
  • Which medications you take, including over-the-counter medicines and herbal supplements
  • If you have any allergies, such as to eggs, soy, or any medications
  • If you smoke, drink alcohol, or take street drugs like cocaine or marijuana
  • If you've ever had a reaction to anesthesia during a past surgery

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The doctor will tell you not to eat or drink anything but water for about 8 hours before your surgery. This is because general anesthesia relaxes your muscles, which can cause food from your stomach to get into your lungs.

You might need to stop taking certain medicines a week or more before your surgery. These include medications and herbal supplements that can make you bleed, such as:

Ask your doctor which medicines you can still take with a small sip of water on the morning of your surgery.

General Anesthesia Risks and Side Effects

You might feel a little drowsy when you wake up from the anesthesia. Other common side effects from the medicine are:

It’s rare, but some people are confused for a few days after their surgery. This is called delirium. It usually goes away after about a week.

Some people have memory trouble after they get general anesthesia. This is more common in people with heart disease, lung disease, Alzheimer's, or Parkinson's disease. The doctor should tell you about all of these possible complications before your surgery.

General anesthesia is safe for most healthy people. Yet it can carry a greater chance of complications if you:

  1. Are obese
  2. Are elderly
  3. Have high blood pressure, diabetes, heart disease, lung disease, epilepsy, or kidney disease
  4. Have obstructive sleep apnea, which causes your breathing to pause many times while you sleep
  5. Smoke
  6. Take medicines such as aspirin, which can make you bleed more
  7. Are allergic to the medicines used in general anesthesia

It’s rare, but you can still be awake after you get general anesthesia. It’s even more unlikely, but you can feel pain during the surgery and not be able to move or tell the doctor you’re awake and in pain. Being awake during surgery can cause long-term emotional problems.

WebMD Medical Reference Reviewed by Hansa D. Bhargava, MD on July 28, 2020

Sources

SOURCES:

American Society of Anesthesiologists: "Effects of Anesthesia."

Mayo Clinic: "General anesthesia: How you prepare," "General Anesthesia: Overview," "General anesthesia: Risks," "General Anesthesia: What you can expect," "General anesthesia: Why it's done."

University of Texas MD Anderson Cancer Center: "What to know about general anesthesia."

National Health Service: "General anesthesia."

National Institute of General Medical Sciences: "Anesthesia Fact Sheet."

Nemours Foundation: "About Anesthesia."

StatPearls: “Anesthesia Stages.”

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