It sounds like the plot of a horror film or a nightmare. You are scheduled for surgery, and the anesthesiologist tells you to “have a good sleep.” But rather than regaining consciousness in the recovery room, you realize at some point that you are awake, but you are still on the operating table. And when your ordeal is over, you find out that your experience was not unique, but anesthesiologists cannot agree on whether there is anything that can be done about it.

Can you really wake up in the middle of surgery?

In the largest study ever of its kind, anesthesiologist Jaideep Pandit of Oxford University Hospitals collected the stories of patients who had told a staff member that they had experienced awareness during their surgery anywhere in the UK or Ireland in 2012. In some 300 cases, both the patient and the doctors were interviewed in an attempt to understand what had happened and to look for common factors.

The study reported a rate of about one case of consciousness for every 19,000 uses of general anesthesia. However, the researchers did not speak to a patient unless they had already brought up the topic with another staff member, so it is impossible to know how many cases may have been missed. The researchers said that most of the occurrences were brief, and that in 51 percent of cases, they occurred before or after the surgery, rather than during it.

The most common experience reported by patients was one of complete paralysis and accompanying panic – which is understandable since many patients are given drugs to relax muscles and prevent reflexive movements. Pandit noted that people are familiar with the experience of pain, but very few know what it is like to be paralyzed. “I thought I was about to die,” said a 12-year-old who regained consciousness during a dental procedure. Some patients also reported pain or the feeling of choking.

Can awakenings during surgery be prevented?

Some doctors advocate the use of a device called a nerve stimulator that could allow them to give lower doses of paralyzing drugs. If the patient woke up enough to feel pain or panic, they would be able to move and alert the doctors. Critics say that in certain types of surgeries, complete paralysis is very important, and they suggest the use of a system using scalp electrodes. Pandit argues that interpreting the signals from the electrodes is difficult and that there is no one reading that shows that a patient is conscious.

The researchers found that 41 percent of patients had ongoing effects from their experiences, including episodes of intense fear and panic, and with some patients comparing their symptoms to those of post-traumatic stress disorder. If you have had general anesthesia and you remember waking up during the procedure, it probably was not in your imagination. You should consider speaking to an attorney, especially if you have symptoms that affect your daily life and your level of functioning. The only thing worse than having a nightmare is waking up and realizing it wasn’t a dream at all.