It sounds like something out of a Stephen King novel: You're under anesthesia for surgery but you wake up during the procedure. Unfortunately, the phenomenon, known as "intraoperative awareness," or "anesthesia awareness," isn't a product of Stephen King's imagination; it's real.
Though anesthesia awareness is rare — estimates put it around approximately one out of every 1,000 surgeries — when it happens it can be traumatic and frightening. So how does it occur, and who is at risk? First, let's explain a little bit about anesthesia.
What Is Anesthesia?
Not all anesthesia is created equal. There are varying levels of sedation that patients can receive during medical procedures.
The first is local anesthesia, which is the safest and most common type. You've probably had local anesthesia before. It numbs a small area with a drug like lidocaine or articaine for procedures like stitches and dental surgeries.
Regional anesthesia is another type of minimal sedation. It blocks pain in larger areas. An epidural, which blocks pain to the lower half of the body during childbirth, is a good example of regional anesthesia. Neither local nor regional anesthesia impacts your cognitive function or level of consciousness.
IV/monitored sedation is used in minor procedures such as colonoscopies and major dental surgeries. You're conscious with moderate sedation, but anesthetized into a very drowsy state or a light sleep. Although you shouldn't feel pain, you may be able to continue to communicate and follow basic instructions from medical staff. But you likely won't remember anything afterward.
Finally, there's general anesthesia. It's administered by an anesthesiologist and used for major surgeries, especially lengthy ones. It causes you to lose consciousness and have no memory of the operation. That's because most general anesthesia surgeries include a neuromuscular-blocking agent that also causes temporary paralysis. Although it's considered safe, there are more risks involved with general anesthesia than with other types.
What Is Anesthesia Awareness?
As we mentioned, when anesthesia works properly, you shouldn't feel pain during a procedure, and during major operations, you should be totally unconscious. But what happens when things go awry?
When a patient experiences anesthesia awareness, they often describe hearing sounds, and feeling sensations and emotions when they were supposed to be unconscious. They are essentially aware or conscious during the procedure. Some might remember the operating room setting or noises from machines. Some even recall pain, but it's usually brief.
Atlanta area occupational therapist Ben Keeling says he will never forget having extensive dental surgery when he was 18. "I heard the nurse count from five to one and then tell the doctor he could start. I knew I was not supposed to be aware by one," he says.
Keeling was heavily sedated, but he was alert enough to hear — and feel — much of what was going on. "I felt pressure and at one point, even felt a cold blade against my gums. It was terrible."
The combination of being aware and terrified, but drowsy with a numb mouth, prevented Keeling from being able to get anyone's attention until the end of surgery.
It's not uncommon for patients to report dreaming during anesthesia. Research shows that most dreams aren't related to anesthesia or awareness, rather they're often short and pleasant and about topics like family or travel.
How Does It Happen?
Despite major advances in medicine, people, with the help of technology, still determine the dosage for anesthesia medicines. Human error, along with equipment failure, is the main cause of patients experiencing awareness while under anesthesia.
Jeanne Smart, a trauma nurse at Grady Hospital in Atlanta, has never, to her knowledge, had a patient who experienced anesthesia awareness, although she agrees that dosing, or even the medication, isn't one-size-fits-all.
"Some people are definitely more difficult to 'put under' than others," she explains. "We use Versed (a benzodiazepine) in pre-op, before anesthesia — it has a helpful side effect of causing amnesia. It's the 'I don't care, I don't remember drug.'"
Some patients also are more high risk for anesthesia awareness, including those with certain medical issues, or those who have had prior problems with anesthesia. People with a history of drug and alcohol abuse, also have a higher chance of waking during surgery.
Emergency surgeries, including C-sections and some heart surgeries, require lower doses of anesthesia for a patient's safety, as do some trauma surgeries. These types of procedures can be more likely to result in some level of awareness.
Can You Prevent Anesthesia Awareness?
There are a few preventative measures you can take to lower your odds of being one of the few who "wake up" during surgery.
Talk to your doctor and anesthesiologist before surgery. It's important to discuss any fears you have about your surgery and any problems you've experienced with past surgeries or anesthesia.
Be completely honest when answering questions, too. For instance, if you have a history of drug and alcohol abuse, you might require a higher dose of anesthesia. Also disclose any medication you take including prescriptions, over-the-counter meds, and herbal and other natural supplements.
If you experience any degree of awareness during surgery, tell your doctor, surgeon or anesthesiologist as soon as you recall the incident. Research shows that immediately after surgery, only one-third of patients who wake up during the operation remember it. It can take up to a month for the rest to recall the experience.
Many patients never report their experiences for several reasons. Some patients aren't distressed enough by it to mention it to their doctor. Some want to be sure the event even happened before they say anything.
Then there are those patients who are so traumatized they essentially go into denial. These are the patients who are at high risk of developing post-traumatic stress disorder (PTSD).
Despite how scary the thought of waking up during surgery sounds, anesthesia awareness occurs very infrequently. The small chance that it will happen to you should not prevent you from having needed surgery.
Fortunately, medical science has come a very long way and "biting the bullet" during a medical procedure is a now a thing of the past. Anesthesia is a medical marvel that has infinitely improved surgery, despite the inherent risks.