Anesthesia awareness, or accidental awareness, is the rare but possible experience of regaining consciousness while under an anesthetic.

Some people may experience a general awareness, while others can recall detailed information, including the experience of pain or feeling paralyzed.

Experiencing this phenomenon can be extremely distressing and may cause severe psychological consequences.

This article explores what there is to know about anesthesia awareness. It discusses the likeness of waking up during surgery, what it may feel like, what happens if it occurs, and more.

A person under general anesthesia, who may experience anesthesia awareness -1.Share on Pinterest
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The possibility of having some type of awareness during surgery varies widely. A 2017 narrative review states that according to previous research, it may be as common as 1 in 600 people to as rare as 1 in 17,000.

The most common occurrence from studies is around 1 in 1,000 people.

Anesthesia awareness may occur due to several causes, such as medication dosing and administration errors or complications with the intravenous (IV) site. Several factors can put people at higher risk for anesthesia awareness.

A 2023 overview of previous research suggests that certain procedures, such as emergency surgeries — especially trauma or cesarean sections (c-section) — have a relatively higher risk of the person developing anesthesia awareness. This is because anesthesia doses sometimes need to be lower for these procedures.

People with a medical history of chronic substance misuse, including alcohol, opioids, or benzodiazepines, are also at higher risk of experiencing anesthesia awareness.

In other situations, the root cause of anesthesia awareness typically lies in the ineffective administration of anesthetic medication. This may be due to human error or equipment error that causes the person having surgery not to receive enough medication.

The goal of anesthetic is for the person to have no awareness during surgery and no memory of it when they wake up.

If anesthesia awareness does occur, there are several different levels of awareness people may experience.

Some people may have a vague memory of a moment in surgery and have no recollection of pain. Others may only have surgery-like flashbacks during dreams but have no specific recall while awake.

A person may have very specific recollections of the surgery, such as who was in the room, what was said, and other details. These people may report having felt pain, while others do not feel pain.

Sometimes, when people start waking up before the muscle relaxer medications wear off, they have feelings of paralysis or being unable to breathe.

The surgical team monitors the person under anesthetic in several ways to ensure they are comfortable and safe during surgery. Whether or not the team recognizes the person has anesthesia awareness depends on several factors.

During surgery, the medical team connects the person under sedation to machines that monitor vital signs, muscle movements, and sometimes brain activity.

Sometimes, a person may exhibit signs on these monitors that they are experiencing some level of awareness. For example, their heart rate or blood pressure may increase, or the neuromuscular monitoring may detect some movement. Any changes to brain activity can be seen on an electroencephalogram (EEG).

Any shifts on these monitors may alert the medical team to the situation. At this time, they may communicate with the person to reassure them and adjust the sedation to help them return to an unaware state.

However, some people verbalize having experienced anesthesia awareness, and the monitoring devices did not indicate this.

If a person experiences anesthesia awareness during surgery, it is very important that they receive support right away.

Some people experience extreme distress or post-traumatic stress disorder (PTSD) and require psychological support to cope with the emotional trauma of the experience.

Before a person has surgery, it is important to have meetings with both the surgeon and anesthesiologist who will oversee the sedation.

These medical professionals will review the person’s overall health and other medical conditions, which helps them make decisions about sedation.

It is important that the person undergoing the procedure tells the medical team their complete medical history, including:

  • all previous surgeries or procedures, and if they had complications
  • a complete list of medications, vitamins, and supplements
  • their use of drugs and alcohol
  • any allergies they have
  • all previous medical diagnoses

The surgical team must also take precautions and follow all protocols to ensure the sedation process goes smoothly. This includes:

  • conducting safety checks
  • calibrating anesthetic and monitoring machines
  • double-checking all medication dosages
  • properly labeling all medications they will use during the procedure
  • ensuring proper placement of all monitoring devices throughout the surgery
  • staying aware of and documenting all monitor signs throughout the procedure

Anesthesia awareness, although rare, can be a distressing experience that may occur during surgery. It happens when a person regains consciousness to some degree while under an anesthetic.

The likelihood of this happening varies according to certain risk factors.

People who do wake up during surgery may experience varying levels of awareness. Some may experience vague cognition without pain, while others may feel pain and have specific recollections of the surgery.

Sometimes, the medical team is aware of the anesthesia awareness and can adjust the sedation, while other times, they are not.

People with anesthesia awareness may require psychological support, as the experience can cause extreme distress or PTSD.

It is important for people having surgery to openly communicate their medical history, current medications, and drug or alcohol use with the surgical team to reduce risk factors.