Anesthesia Awareness (Waking Up During Surgery)

What is anesthesia awareness?

Anesthesia awareness is when a person under general anesthesia “wakes up” during surgery. This isn’t “waking” in the typical sense. It’s more like brief moments of consciousness. But effects vary, and people experience this awareness in different ways.

During surgery, someone with anesthesia awareness might:

• Hear sounds or conversations going on around them.
• Be in a dreamlike state.
• Wake up and realize they can’t move.
• Feel pressure or (in rare instances) pain.

Anesthesia awareness is something that happens under general anesthesia. It doesn’t occur with other types of sedation. This is because general anesthesia is the only type of sedation that takes over your body’s automatic functions, like breathing. Other types (like IV sedation or “twilight sleep”) put you in a lower state of consciousness, but you can still breathe on your own and talk to your medical team, if necessary.

What are the odds of anesthesia awareness?

Anesthesia awareness is rare, but it’s hard to know exact numbers. Some people may not remember anything about their surgery until one or two weeks later. Others may experience anesthesia awareness right away but not report it.

There have been several research studies to figure out how often anesthesia awareness happens. Findings vary, but on average, anesthesia awareness occurs in about 1 to 2 out of every 1,000 cases (less than 0.2% of the time).

What causes anesthesia awareness?

Three issues can result in anesthesia awareness:

1. Insufficient drug administration: This means the anesthesia care provider didn’t give enough anesthetic drugs. Most often, this happens during emergency procedures like heart surgeries, cesarean sections or surgeries following traumatic injuries.
2. Different anesthetic requirements: This is when the anesthesiologist gives a standard amount of anesthetic drugs to a person with different anesthetic needs. It happens most often to severely anxious people, those who have substance use disorders and individuals who’ve experienced anesthesia awareness in the past.
3. Anesthesia machine malfunction: Anesthesia awareness can occur if the machinery in the operating room malfunctions, or if the medical staff failed to run proper equipment checks.

Anesthesia awareness risk factors

You have a higher risk of anesthesia awareness if you:

• Smoke.
• Have multiple medical conditions.
• Have difficulty breathing (from things like respiratory conditions or lung disease).
• Have a history of substance use disorder (SUD).

People are also more likely to experience anesthesia awareness during procedures where it’s not safe to use the usual amount of sedation. This may include:

• C-sections.
• Heart surgery.
• Emergency surgery to treat trauma or blood loss.

Do you feel pain with anesthesia awareness?

Pain during anesthesia awareness is rare, but it’s possible. While most people recall things like sounds or conversations, some remember having a sore throat from the intubation tube or pain at their incision sites.

Are there long-term complications associated with anesthesia awareness?

Not everyone who experiences anesthesia awareness will have long-term effects. But in severe cases, people may develop:

• Anxiety.
• Depression.
• Nightmare disorder.
• PTSD (post-traumatic stress disorder).

People who develop these complications may feel a lingering sense of helplessness. As a result, they may avoid medical appointments altogether, putting themselves at a higher risk for health issues. If you’ve experienced anesthesia awareness, seeking help from a psychologist can empower you and improve your quality of life.

Can anesthesia awareness be detected?

While healthcare providers can tell if you’re sedated, they can’t always tell if you’re unconscious.

Anesthesiologists can detect your level of sedation by monitoring your vital signs — things like blood pressure, breathing rate and pupil size. But measuring consciousness is tricky. Because the drugs used during general anesthesia affect your autonomic nervous system, you can’t move around or speak. So, your provider can’t measure your consciousness the same way they measure your sedation level.

But there are tools that help your provider measure electrical activity in your brain during surgery. This helps them estimate your level of consciousness. First, your provider will take an electroencephalogram (EEG). For this test, they’ll place small sensors on your scalp. These sensors will pick up your brain’s electrical signals. Once they have your EEG results, they can use them in combination with other monitoring methods like:

• Bispectral Index™ monitoring (BIS). According to research, the BIS is the most reliable tool for measuring how sedated you are. It records your EEG results and generates a number between zero and 100. The lower the number, the deeper the sedation. For general anesthesia, the goal is to keep that number somewhere between 40 and 60.
• Auditory evoked potentials (AEP) monitor. This device records and mathematically processes the electrical activity in your brainstem and cerebral cortex. Your provider will place headphones over your ears and play certain sounds. The device then processes your brain’s response and comes up with a number between zero to 100. The lower the number, the deeper the anesthesia.
• Narcotrend®. Like BIS, Narcotrend uses your EEG results to estimate the depth of anesthesia. It classifies your results into six letters (A through F) and a number (zero through 100). Results can range from “awake” to “electrical silence.”

How do healthcare providers diagnose anesthesia awareness?

The best way for healthcare providers to know whether you’ve experienced anesthesia awareness is to ask you questions after your procedure. The Brice Interview is one way that healthcare providers do this. It includes a few short questions like:

• What’s the last thing you remember before surgery?
• What’s the first thing you remember after surgery?
• Do you remember anything during surgery?
• Did you have any dreams during surgery?

Can you prevent anesthesia awareness?

If you’re concerned about anesthesia awareness, discuss it with your anesthesia care provider. They’ll tell you about the steps they’ll take to reduce the risk of it occurring, including:

• Telling your healthcare provider about any medications or supplements you take.
• Discussing your medical history with your provider in detail.
• Bringing up any questions or concerns you have.
• If you’ve had anesthesia awareness in the past, being sure to tell your provider.
• Avoiding known risk factors.

Anesthesia awareness doesn’t occur because you’ve done something wrong. It’s just something that happens, and experts continue to research why.

What should I do if I have anesthesia awareness?

If you experience anesthesia awareness, tell your healthcare provider right away. Explain what happened in as much detail as you can remember. Your provider can document the occurrence and take steps to reduce your risk of anesthesia awareness in the future.

What’s the outlook for people who’ve experienced anesthesia awareness?

It depends on the situation and the severity of the effects. For example, someone who recalls a moment of conversation during surgery may not develop troubling side effects. But someone who feels pain or becomes keenly aware of things happening around them may develop more severe, long-lasting psychological complications. Most patients who’ve had anesthesia awareness can safely get anesthesia again in the future with a low risk of it happening again.

If you’ve experienced anesthesia awareness, talk openly with your healthcare provider about how it affects your day-to-day life. They can refer you to a psychologist or psychiatrist for testing and recommend appropriate resources.

A note from Cleveland Clinic

The thought of waking up during surgery is so terrifying that there are several movies exploring this very topic. While anesthesia awareness is rare, the fear around it is commonplace, living in our collective psyche. Its long-term psychological effects shouldn’t be ignored. At the same time, it shouldn’t keep you from getting the procedures you need to stay healthy. Anesthesia care providers use advanced monitoring tools to prevent it. And scientists continue to research why some people have anesthesia awareness and others don’t. If you’ve experienced this phenomenon — or you’re worried that you might — talk with your anesthesia care provider. They may be able to put your mind at ease.