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A new state of consciousness may exist for surgery patients

Teresa Tanoos's picture
Consciousness while in surgery

If you have ever had general anesthesia during surgery, you know what it’s like to wake up afterward as if only seconds passed, not having any memory about the surgery whatsoever.

Indeed, when anesthesia is administered properly, it is very rare for patients to wake up during surgery.

However, a new study suggests that a possible third state of mind exists that allows patients to respond to a command – without being disturbed by the surgery or by pain.

Dr. Jaideep Pandit, an anesthetist at St John's College in England, discussed this possibility Thursday at The Annual Congress of the Association of Anaesthetists of Great Britain and Ireland.

Pandit, who refers to this state of mind as “dysanaesthesia”, meaning the patient is neither fully conscious nor unconscious, says evidence of its existence is supported by a recent study, published September 12 in the journal Anaesthesia.

The study involved 34 surgical patients who were anesthetized, with their entire bodies paralyzed, except for their forearm to allow them to move their fingers in response to commands, or to show a sign if they were awake or in pain during surgery.

The results of the study found that one-third of the 34 surgery patients moved their finger if asked to while they were under what appeared to be adequate anesthesia.

"What's more remarkable is that they only move their fingers if they are asked. None of the patients spontaneously responded to the surgery. They are presumably not in pain," said Pandit, who wrote an editorial about the study.

Doctors usually monitor patients continuously while under anesthesia, administering anesthetic drugs as needed to make sure the patient receives enough medication to remain deeply unconscious during surgery.

However, there is a debate over the reliability of technologies used in determining how unconsciousness an anesthetized patient really is.

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"We don't have a model for consciousness," Pandit explained. "It is very difficult to design a monitor, to monitor something you don't have a model for."

The goal of the study was to investigate whether the 34 patients were fully unconscious when the monitoring technology typically used in operating rooms indicated they were.

In order to achieve this goal, the research team kept each patient’s arms separated from the rest of the body, which was receiving routine paralyzing drugs to block the blood supply. If they were still conscious, the patients were able to move their arms.

For those patients who responded when asked to move their hand, the doctors interpreted such movement as a sign of consciousness, and therefore increased the dose of anesthesia.

But Pandit argues that these patients were not "conscious” because of the fact that they only responded when asked to move their hand, which was not a spontaneous movement; rather, it showed their state of mind was different from normal consciousness, Pandit explained.

Previous surveys reveal that when patients were asked if they recalled being aware during surgery, about 1 in 500 reported they did. However, in a recent national United Kingdom survey that did not ask patients if they were aware during surgery, approximately 1 in 15,000 patients spontaneously responded that they were – and only 1 in 45,000 reported being disturbed by discomfort or pain during their surgery.

According to Pandit, these statistics combined suggest there is a state of mind in which patients are aware, but not reporting it – perhaps because it is an acceptable and neutral experience for them.

In other words, they may be aware of their surroundings to a certain extent, but not so much that it bothers them, especially since they are not in pain.

Pandit says his hypothesis may serve as a basis for developing anesthesia monitors in the future, adding that even though the state of dysanaesthesia may appear harmless, it could be a precursor to uncomfortable states of awareness during surgery that both doctors and patients would like to avoid.

"It's a hypothesis for future research, it's something that we can explore further and design experiment to see if it really exist," Pandit said.

SOURCES: 1. Annual Congress of the Association of Anaesthetists of Great Britain and Ireland, September 18-20, 2013. 2. The Psychologist, "Psychology in the operating theatre" (PDF), July 2013.