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Anesthesia awareness is a rare but worrisome occurrence that can happen during a procedure where general anesthesia is used.

The goal of general anesthesia is to put you into a form of reversible coma. You shouldn’t be able to feel pain or have any awareness of what’s going on. However, in some rare instances, people can become “aware” during general anesthesia, even if they aren’t exactly awake.

Awareness is a difficult term to define, and some research has focused on how exactly doctors and anesthesiologists can tell how deeply sedated you are.

During some procedures, it’s possible — and even desired — for you to respond in certain ways, either physically or even verbally. But you still shouldn’t feel pain or remember what happened after you are brought out of sedation.

Most of the time, general anesthesia is used for surgeries, but there have been reports from people who remember things said or done during the procedure. Some even say that they felt pain but were unable to move. This is anesthesia awareness.

“Awake” is an abstract term when it comes to sedation, as sleep and sedation are very different things that are subject to one’s own perception. The goal of sedation or anesthesia is to make you unconscious — unable to interact, feel pain, or remember anything.

There are varying levels of sedation that may be used during a procedure, and you should know before a procedure what type of sedation you’ll have.

Minimal sedation

In this level of sedation, you may be given calming medications, but your awareness and physical state shouldn’t be altered.

Moderate sedation or ‘conscious sedation’

During conscious sedation, you remain “awake,” but in a state of lowered consciousness. You can respond but may be hazy. Your breathing or other physical functions shouldn’t be affected.

Deep sedation

With deep sedation, you’ll be “asleep” or in a lower state of consciousness. While you’ll be able to respond in some way to pain or other stimulation, you shouldn’t easily awaken or feel pain. You also probably won’t remember your procedure.

During deep sedation, your breathing or other body functions may be impaired, so you’ll be monitored closely and offered support with tools like a ventilator or medications to keep you heart rate or blood pressure strong.

General anesthesia

During general anesthesia, you will be placed in the deepest level of sedation, unable to feel pain or respond to any stimulation. Your body functions, like breathing, will be taken over for you.

How it works

Your level of sedation is measured by your response to stimulation and how well you’re able to maintain vital functions like breathing. Sedation is given continuously throughout your procedure and monitored closely.

General sedation usually occurs in three stages:

  • induction, or the initiation of anesthesia
  • maintenance, or the continued administration of sedation
  • recovery, or the emergence from sedation

As with any procedure, there are risks or errors that can occur. In some cases:

  • people are administered incorrect medications during anesthesia
  • medications are given at the wrong level or dose
  • the device delivering the medication malfunctions
  • you fail to have the expected response (this is most common in people with substance use disorder)

There have been many studies to try and find out exactly how often this happens, but it can be difficult to detect anesthesia awareness. Some people may have flashbacks or memories to a procedure after it has happened and be hesitant to discuss it.

Different studies have estimated the frequency of anesthesia awareness at as little as 1 in almost 17,000 procedures, and as often as 1 in 600. The accepted average is about 1 in 1,000.

When you think about waking up during surgery, it may conjure visions of sitting up mid-surgery and screaming at your surgeon.

This, of course, should never happen. Surgery won’t begin until your surgeon is confident you’re well-sedated. Your sedation level will be closely monitored and maintained throughout the procedure by measuring your responsiveness and physical vital signs.

For people who report anesthesia awareness, the stories are far from what you may think. Reports of “waking up” during surgery are limited to:

  • memories of sounds or things that were said.
  • remembering the feeling that it was difficult to breathe
  • recalling feelings of pressure or pain
  • feelings of helplessness

There isn’t much you can do in the moment if you experience anesthesia awareness. If you become aware during general anesthesia or deep sedation, you’ll most likely not be able to physically move or communicate what you’re feeling.

Many people who experience anesthesia awareness have vague or fuzzy memories of a procedure after they wake up. Most of the medications used for anesthesia can affect the memory, so you may even have some level of awareness during a procedure and not remember it afterward.

If you do remember pain, pressure, sounds, or even visions, speak with your surgeon about it. These memories may cause:

Counseling may help.

If during your surgery there’s any indication that you are waking up or becoming aware, your surgical team will increase your level of sedation to achieve the desired effect. You’ll also be monitored for signs of overdose. If this happens, your sedation may be reduced or even reversed.

While your surgery team will monitor your sedation using your vital signs and responses to stimulation to gauge your level of sedation, it can be difficult to detect awareness. Various tools and monitoring devices have been used to measure brain waves or electrical signals in the body, but there are no real reliable ways to measure consciousness.

There are a number of reasons you may experience consciousness or awareness while under general anesthesia, but ultimately, the issue is the failed delivery of anesthesia medication.

This can happen due to mistakes made by the surgical team — so-called “syringe swaps,” where the wrong medication is used, or technical or device errors that don’t give you enough medication.

If you have multiple medical conditions or you’re being sedated under difficult conditions, you also run the risk of anesthesia awareness. This is most common with cesarean deliveries, some heart surgeries, and other delicate operations where it may not be safe to use the usual amount of sedation.

Before you undergo surgery, you should meet with the surgeon who will perform the procedure, as well as the anesthesiologist in charge of your sedation. Your overall health, other medical conditions, and any medications you take will be reviewed.

Be sure to tell your anesthesiologist about:

  • your medical history
  • allergies
  • prior surgical complications
  • drug and alcohol use
  • current medications including vitamins and supplements

Surgical teams should also take a number of precautions to ensure successful sedation, including:

  • regular calibrations and safety checks of machines used for anesthesia
  • labeling of any medications that are to be used
  • double-checking of medications and doses to be used during the procedure
  • appropriate monitoring of adequate sedation levels

Surgery can be concerning enough without worrying about whether you’ll wake up in the middle of the procedure. While you’re extremely unlikely to become truly awake during a surgery, there’s a chance that you may remember a feeling of pressure, sounds, or even conversations that occurred during the procedure.

While rare, this happens in about one in 1,000 surgeries, often because of inadequate delivery or effect of medications used for anesthesia.

Anesthesia awareness is traumatic in many cases, and you may need counseling. Be sure to talk with your surgical team about any addictions or medical history that could decrease how effective anesthesia may be to you, and discuss any memories you have of the procedures with your doctor.