Belle Riskin awoke in an operating room as doctors were pushing a breathing tube down her throat. Riskin was choking, but she couldn't move. She couldn't see, breathe or scream.
"I was terrified. Why is this happening to me? Why can't I feel my arms? I could feel my heart pounding in my head. It was like being buried alive, but with somebody shoving something down your throat," said Riskin, a 48-year-old Clifton, N.J., resident.
"I knew I was conscious, that something was going on during the surgery," she said. "I had just enough awareness to know I was being intubated."
Unable to even flutter an eyelash, she had no way of letting her surgeons know she was conscious.
Some 26,000 patients awaken during surgery under general anesthesia every year in the United States. This comes out to about 100 patients every weekday, according to a study to be published this summer.
Some of them recall feeling pain. Others remember, later in the recovery room, that they heard surgical instruments clanking in a metal pan or conversations between doctors and nurses. Some even were aware of their flesh and bone being cut.
"I wouldn't want to be one of those patients," said Dr. Mark Schlesinger, chief of anesthesiology at Hackensack University Medical Center in New Jersey.
Schlesinger is not surprised that some patients come to on the operating table. "I know it is a real thing. There are a lot of people who may experience awareness who are just afraid to say something" afterward, perhaps fearing their doctor would not believe them, he said.
The incidents, known as "interoperative awareness with recall," are rare – only 0.13 percent of the 20 million operations performed in this country each year, according to the study by Aspect Medical Systems of Newton, Mass.
Anesthesiologists expect the occurrences to decrease as more hospitals use a Bispectral Index (BIS) monitor – a device that measures people's electrical brain waves to ensure they aren't aware of what's happening during the surgery.
Through a sensor taped to the forehead, the device gauges a patient's level of consciousness in a numerical reading from zero to 100. An anesthesiologist uses the monitor to maintain the proper amount of anesthesia and sedatives. Because patients are given more accurate doses, the device also lessens nausea after the surgery.
Like other physicians, Schlesinger relies on his years of training and equipment that track a patient's vital signs while administering anesthesia during surgery. He has also used the BIS monitor since it received federal approval in 1998.
"When the technology came out, I felt very strongly about it," Schlesinger said. "I implemented the monitor across the board for anesthesia here at Hackensack. So we use the BIS in every operating room."
Surgeons are also traumatized if they hear a patient may have been even partially aware of what was going on, said Dr. Aryeh Shander, chief of anesthesiology and critical care medicine at Englewood Hospital and Medical Center in Englewood, N.J.
"It's devastating to the medical team. To think you can operate on somebody who's awake is horrible for the surgeon, not to the degree that it is for the patient. But it must also be absolutely devastating (to the surgeon)," said Shander, an early user of BIS monitoring in New Jersey.
The problem for anesthesiologists it that "it's hard to tell, with the different drugs they use, whether a patient is completely anesthetized or not," Shander said.
Anesthesiologists have guidelines for how much anesthesia to administer and for following vital signs, such as heart rate and blood pressure. But these are only secondary markers that do not tell whether a patient is completely unconscious.
"It's like flying in fog. Though you have instruments, you still can't see," he said.
Awareness during surgery became more of a factor in the past few decades with the use of muscle relaxants to paralyze a patient's involuntary reactions to pain that can disrupt surgery.
"In the old days, before muscle relaxants, a patient could move to say, 'I'm awake.' You could alert your anesthesiologist" in the rare case that awareness occurs, Schlesinger said. Muscle relaxants may mask the outward signs that a patient is not receiving enough anesthesia.
"These patients who have awareness are receiving anesthesia, (but) have some level of not being anesthetized. Some patients are truly aware throughout surgery, with complete knowledge of what's going on and no ability to communicate, and feeling pain. It must be a very, very frightening experience," Shander said.
The BIS monitor is not infallible, and its effectiveness depends on the interpretive skills of the anesthesiologist. "The BIS brings us closer. This is the first generation. There are competing companies that make the monitor, and the specificity is getting better," Shander said.