Russell gives the instruction to start the infusion pumps, which will push the anesthetic into her bloodstream, and then puts a gas mask over her mouth and nose. “Take a big deep breath.” Within seconds she is gone.

* * *

In 1993, as a little-known anesthesiologist from the recursive Hull, England, Russell published a startling study. Using a technique almost primitive in its simplicity, he monitored 32 women undergoing major gynecological surgery at the Hull Royal Infirmary to assess their levels of consciousness. The results convinced him to stop the trial halfway through.

The women were put to sleep with a low-dose anesthetic cocktail that had been recently lauded as providing protection against awareness. The main ingredients were the (then) relatively new drug midazolam, along with a painkiller and muscle relaxant to effectively paralyze her throughout the surgery. Before the women were anesthetized, however, Russell attached what was essentially a blood-pressure cuff around each woman’s forearm. The cuff was then tightened to act as a tourniquet that prevented the flow of blood, and therefore muscle relaxant, to the right hand. Russell hoped to leave open a simple but ingenious channel of communication—like a priority phone line—on the off chance that anyone was there to answer him.

Once the women were unconscious Russell put headphones over their ears through which, throughout all but the final minutes of the operation, he played a prerecorded one-minute continuous-loop cassette. Each message would begin with Russell’s voice repeating the patient’s name twice. Then each woman would hear an identical message. “This is Dr. Russell speaking. If you can hear me, I would like you to open and close the fingers of your right hand, open and close the fingers of your right hand.”

Under the study design, if a patient appeared to move her hand in response to the taped command, Russell was to hold her hand, raise one of the earpieces and say her name, then deliver this instruction: “If you can hear me, squeeze my fingers.” If the woman responded, Russell would ask her to let him know, by squeezing again, if she was feeling any pain. In either of these scenarios, he would then administer a hypnotic drug to put her back to sleep.

By the time he had tested 32 women, 23 had squeezed his hand when asked if they could hear. Twenty of them indicated they were in pain. At this point he stopped the study.

When interviewed in the recovery room, none of the women claimed to remember anything, though three days later several showed some signs of recall. Two agreed after prompting that they had been asked to do something with their right hand. Neither of them could remember what it was, but while they were thinking about it, said Russell, both involuntarily opened and closed that hand. Fourteen of the patients in the study (including one who was later excluded) showed some signs of light anesthesia (increased heart rate, blood-pressure changes, sweating, tears), but this was true of fewer than half of the hand-squeezers.* Overall, said Russell, such physical signs “seemed of little value” in predicting intraoperative consciousness.