Anesthesia, page 17
Not necessarily, warned Bargh. In a series of classic experiments, he and his team showed that people could be unwittingly primed to butt into a conversation simply by first getting them to rearrange sentences that included words such as “rude,” “obnoxious” and “bold.” In another study, people exposed to words such as “old,” “lonely” and “bingo” were timed walking away from the experiment more slowly than their fellow participants. In another, non–African American students shown subliminal images of African American faces went on to behave more aggressively toward experimenters than those who had been primed with Caucasian faces. All without the participants having any idea that they were being manipulated. Again, the results have been inconsistent. Several well-publicized studies early this decade failed to replicate various of Bargh’s findings on behavior priming. But a 2016 meta-analysis of the literature in the prestigious Psychological Bulletin confirmed a small but robust effect—particularly when the behavior or goal was important to the person being primed. It also pointed to “potential real-world implications” of such priming.
The real world, of course, is even more slippery than the (relatively) controlled confines of the testing laboratory.
I met Kathryn Hall, like several of the people who wander in and out of these pages, at a writers center outside Sydney. She was taking time away from her daytime jobs as a graphic artist and mother to work on a book for teenagers. A few years before, Kathryn had gone to the hospital for an operation on her sinuses. For some reason I have always imagined a sinus as a body part, like a small bit of spiral-shaped pasta tucked somewhere up the nasal passage, but it turns out to be more of an absence: a cavity in the bone. Kathryn, in any case, remembers nothing apart from waking congested and in pain. And feeling a bit odd. “This kind of peculiar feeling,” she said. “I had this shaky sensation. Like my body was on edge. A shaky sensation under my skin. I just put it down to the anesthetic.”
But almost a month later she was still having that sensation: “Like I was on edge all the time, and the anxiety thing creeping in, and starting to be worried. Just feeling like something was wrong with me.” She felt that she was going to die.
The feeling escalated over three or four days. At first, she said, “it was more a sense of feeling out of control, something happening in my body. Shortness of breath, couldn’t breathe properly, and just that shaky feeling, but much, much more intense.” By the fourth day she was in a strange doctor’s surgery, her heart doing a drum solo. “I had pain in my neck. I couldn’t breathe. It was absolutely terrifying.” The doctor examined her and told her quietly that she was having a panic attack.
Although Kathryn had dealt with anxiety before, triggered in part by a serious car accident she had been in as a younger woman, she said she had never experienced anything like these attacks. Kathryn went to her own GP and told her she suspected that the feeling was linked somehow to the operation. She had a vague memory of something her anesthesiologist had mentioned when he came and saw her afterward. About her blood pressure having plummeted during the surgery—the fact that it had been tricky to get it back up. “It was just a very passing comment. It stuck with me, but I never really thought about it.” Her GP was unconvinced; she felt Kathryn was suffering from an unrelated depression as well as anxiety, and recommended drugs and counseling. Kathryn duly began seeing a counselor. The process has been helping somewhat. Her psychologist believes the anesthetic might have reopened a door to traumatic events in Kathryn’s earlier life. She hasn’t had any more panic attacks. “But I still do have this very base concern that I’m dying, that there’s something wrong.”
She just doesn’t know what it is.
Three things we know, and one we don’t:
We know that the brain’s auditory pathways can continue to process sound after we are unconscious.
We know that implicit memory or priming can continue in anesthetized surgical patients to the same degree as in conscious volunteers.
We know too that, at light doses of some anesthetic drugs, while patients quickly lose the ability to form conscious memories of disturbing images, the threat-detecting amygdala can keep pinging away behind the scenes.
What we don’t know is what any of this might mean for a real person having real surgery in a real operating theater.
All of which helps explain the continuing allure of an odd and inventive German study from more than twenty years back. In the mid-nineties, a team led by anesthesiologist Dierk Schwender played tape recordings to forty-five people having heart surgery using one of three different anesthetics. Some time between when their chests were sawn open and bypass surgery began, two-thirds of the patients were played a ten-minute message including an abridged version of Daniel Defoe’s Robinson Crusoe—the story of a castaway who, shipwrecked and alone on an inhospitable island, eventually learns to survive and flourish with the help and companionship of Man Friday. “The story was meant to be a parable for the patients to cope with their current difficult situation and facilitate postoperative recovery,” explained the authors. Three to five days later they interviewed the patients. First they asked each if they remembered anything of the surgery. None did. Then they asked them to say the first word that came to mind when they heard the word “Friday.”
“Last working day of the week,” said one. “Fish for lunch and dinner,” said another.
But other patients went on to make a different connection.
“When you say Friday, I think of an island and the story of Robinson Crusoe,” said one, “but I think this has nothing to do with your question.”
“When you say Friday,” said another, “I remember that when I was a child we used to play on a little island in a river near my parents’ home. We called that place Robinson island.”
None of the fifteen patients in the control group—those who had not been played the story tape—linked the word “Friday” to Robinson Crusoe. Nearly a quarter of the remaining thirty did: seven people, five of them with one particular anesthetic.
Schwender and his team had used an EEG to monitor the transmission of electrical impulses from each patient’s ear to the part of the brain responsible for processing sound. Some patients’ EEG readings showed little or no activity in the primary auditory cortex during the time when the messages were delivered; and those subjects showed no evidence of hidden memory. But the patients who mentioned Robinson Crusoe were all among those in whom these auditory signals (known as “auditory evoked potentials”) had continued. In other words, their brains were still processing the words, at least partially.
The Robinson Crusoe study has been something of a Rorschach’s test for those interested in how much patients can take in when unconscious. Different researchers have seen different things in the study’s blurred outline. To Schwender it suggested a measurement tool (auditory evoked potentials) that might be used by anesthesiologists to prevent surgical patients forming not only conscious but unconscious memories. To others its message was that different anesthetics provided differing levels of protection against memory formation. For some its main lesson was that patients do not form memories at deeper levels of anesthesia; for others that even an adequately anesthetized patient can take in information.
To British psychologist Michael Wang, however, it was the story at the center of the study—of a man alone on an island—that provided its force. For Wang, it was the emotional correspondence between Crusoe’s predicament and the patients’ own experiences that most resonated. This study, he argued at the time, hinted at something deeper than mere word association. It suggested an emotional learning more resistant than verbal memory or language to the effects of some drugs: an inarticulate feeling network that could be activated unconsciously and that might then translate into actions and behaviors that could affect our lives in all sorts of ways we couldn’t imagine. Abracadabra. As I say it so it will be.
It’s an appealing story. Rich, resonant. Allusive.
Except that many years later, not long before he retired, Wang would attempt a replication of the Man Friday study, this time with intensive care patients. The result? Nothing. There were differences in the staging of the experiment (they waited longer before interviewing the patients). But none that even Wang felt could account for the result. It was, he acknowledged, disappointing.
So there we are. Again.
Now you see it, now you don’t.
•
There is something very reassuring about talking with British psychologist Jackie Andrade. I don’t know what she does after hours when she is not teaching and researching and speaking to people like me. Maybe she behaves erratically. Maybe she makes wild unsubstantiated claims or stands too close to strangers. But I don’t think so. She has a soft Devon accent and a calm and straightforward way of explaining her work that, each time I have heard her speak, has left me feeling, I suppose, that I am in good hands. The first time she heard claims that people could form hidden memories while anesthetized, she was incredulous. Even after she was persuaded by colleagues in the mid-nineties to carry out a review of the available literature, she remained underwhelmed at the evidence. The issue, she felt certain, was in the study designs or anesthetic techniques. “I was the biggest skeptic of the lot.” This was not to say she was convinced by Ted Eger’s 1995 rerun of Bernard Levinson’s fake crisis. (“I think it would have been very interesting had it worked . . . I think it’s less interesting that it didn’t replicate it.”) In the end, however, like Eger, she determined to let science decide.
After a preliminary study led by one of her PhD students, Catherine Deeprose, the pair set out, like Eger and Bennett a decade earlier, to settle the matter. Working with surgical patients drugged with the intravenous anesthetic propofol and nitrous oxide, and using the BIS monitor, they mounted a painstaking study designed to confirm whether memories could really be awakened and reactivated during deep anesthesia. “I was convinced,” said Andrade years later from Devon, where she is now professor of psychology at Plymouth University, “that if you did the tests properly and used a good measure of depth of anesthesia, to ensure patients were truly unconscious, there would be no memory.”
But there was.
“And we did do them properly!”
How big was the effect? Not big. Pretty small in fact. Presenting words to anesthetized patients improved their chances of later selecting those words in a word-stem completion test by 33 percent, but it still only amounted to a “quite small” figure, said Andrade. On average patients remembered half a word out of a set of seven. Nor was this new information they were learning—simply existing memories being jogged.
Even so.
“Having said it’s small, the reason I think it could be really important—and this is speculative—is that for ethical reasons we’ve only done studies with neutral words that people are very familiar with already—words like table and automobile, things like that.”
Andrade then went on to hypothesize (as Levinson had suggested about Ted Eger’s replication of his own fake-crisis study) that the reason the experimental effect was so small was because the words did not matter enough for the patient to process them. Offer the anesthetized you or me something we care about—our name, for instance, or the name of our illness; or a prognosis—and we need less mental juice to process that information than for something irrelevant. It’s a bit like suddenly hearing ourselves mentioned across a crowded room despite all the competing chatter. Basically, we have had so much practice over a lifetime of recognizing that (very particular) word that it skates nimbly along its own well-worn brain pathways with minimal effort on the part of our already overloaded neurons. Andrade makes a parallel with anesthesia. “Even if there’s very little activity left in your auditory cortex, this information can get through better than irrelevant information.”
The other reason she believes her study is important is that, while the memories being created in her team’s experiments are single words that piggyback on knowledge the patient already has, each word can trigger a network of associations.
“So if you’re self-conscious about your body, for instance, and you overhear somebody saying ‘fat’ and you interpret that as applied to you, that won’t just activate the word ‘fat,’ it will activate all your anxieties about your weight and how you look and those sorts of things. I’m picking this example because this is something that anaesthetists do say about their patients, because it’s harder to anesthetize some-body who’s obese, so they’re very likely to comment on their weight because it’s important for them in deciding how to do the anesthetic.”
Andrade’s research raises the possibility that, in this instance, the patient’s brain could still react to those comments even while she or he was anesthetized. Again, she said, all speculative—and likely to stay that way. Even if, ethically, researchers could go around saying alarming or insulting things to unconscious surgical patients, it would be very difficult to attribute any changes in the patients’ behavior solely to hidden memories of the event. There are all sorts of reasons why people feel odd or upset after surgery: pain, sleeplessness, anxiety, changes to body image. And of course many—most—people seem to leave hospital feeling relatively sanguine. But this did not have to mean the issue was trivial, Andrade said. “Because of course, in the course of doing their work, surgeons and anaesthetists and theatre staff can say things that are much more profound from the patient’s point of view than we could ever do as experimenters.”
Dreams
One day early in my research, I rang my father and told him I was writing about anesthesia.
“Oh,” he said, “fancy that. I had one of my ether dreams just the other day.”
My father, like many in his generation, had his tonsils taken out when he was around ten years old. This would have been in the late 1940s. He does not know what anesthetic he was given, though he remembers clearly something being held against his face. Fear. A sense of suffocation. A bad smell. Probably ether; maybe another early anesthetic, chloroform. As he went under, he had a vision or dream. In the dream, he said, he was sitting in the sky with his legs straight out in front of him. As he sat, feeling quite relaxed, he saw in the distance a cloud moving toward him, a large white cloud, “which came inexorably closer and closer.” The closer the cloud came, the more uneasy my father became, until it slowly enveloped him, first the toes, then the thighs, “then the lot.” In the years since, he had experienced a recurring nightmare in which this vision, or variations on it, was repeated. There he would be sitting in the sky, legs stuck out in front of him, and then there in the distance, moving toward him, was the cloud.
What was the feeling? I asked him.
“Oh,” he said. “Oh. Absolute terror.”
Dreams occupy an amorphous space in anesthesia theory and practice. Patients often wake from surgery and report having dreamed (recent studies suggest somewhere between 20 and 50 percent of patients might do it) and traditionally doctors have paid little attention to these reports. Most doctors see dreams as curiosities, or perhaps as a sort of psychic static—like “noise” in digital photography; an artifact or drug-induced hallucination. Certainly they have been happening for as long as people have been being anesthetized.
Not long after William Morton’s miraculous 1846 demonstration of ether anesthesia, a surgeon called Henry Bigelow visited Morton’s rooms to witness the dentist at work with his new technique. Bigelow had already had some experience with ether, as with nitrous oxide—though not in a surgical context. “In my own former experience,” he noted of ether, “the exhilaration has been quite as great, though perhaps less pleasurable, than that of this gas [nitrous oxide], or of the Egyptian haschish.” He watched, fascinated, as Morton moved through his list of patients. One, “A boy of sixteen, of medium stature and strength,” inhaled for some time and eventually passed out for three minutes, during which time Morton extracted a troublesome molar. “At the moment of extraction the features assumed an expression of pain, and the hand was raised. Upon coming to himself he said he had felt no pain but had had a “first rate dream—very quiet [. . .] and had dreamed of Napoleon . . .”
Another patient, wrote Bigelow,
was a healthy-looking, middle-aged woman, who inhaled the vapour for four minutes; in the course of the next two minutes a back tooth was extracted, and the patient continued smiling in her sleep for three minutes more. Pulse 120, not affected at the moment of the operation, but smaller during sleep. Upon coming to herself, she exclaimed that “it was beautiful—she dreamed of being at home—it seemed as if she had been gone a month.”
These results, said Bigelow, were typical of ether: “Dr. Morton states that in upward of two hundred patients, similar effects have been produced.”
The character of the lethargic state, which follows this inhalation, is peculiar. The patient loses his individuality and awakes after a certain period, either entirely unconscious of what has taken place, or retaining only a faint recollection of it. Severe pain is sometimes remembered as being of a dull character; sometimes the operation is supposed by the patient to be performed upon somebody else.
From time to time, in fact, the dreams were so enjoyable that doctors were shocked. American anesthesiologists Robert Strickland and John Butterworth noted a decade ago that within a few years of Ether Day reports had started appearing in journals of patients, mainly women, waking from anesthesia in a state of high arousal, some reporting erotic dreams, some using obscene language. New England physician Moreton Stille cited a report in the 1850s of a woman in Germany emerging from an ether anesthetic “in a highly excited state . . . her eyes sparkled and a certain erotic excitation was very observable.” In a case mentioned by a Professor Dubois, a Parisian prostitute having vaginal surgery later reported erotic dreams. In another of Dubois’s cases, “The woman drew an attendant toward her to kiss, as she was lapsing into insensibility, and this woman afterward confessed to dreaming of coitus with her husband while she lay etherized.”
