With anesthetics properly given, very few patients wake up
during surgery. However, new findings point to the possibility of a state of
mind in which a patient is neither fully conscious nor unconscious, experts
say.
This possible third state of consciousness may be a state in
which patients can respond to a command, but are not disturbed by pain or the
surgery, according to Dr. Jaideep Pandit, anesthetist at St John's College in
England, who discussed the idea Thursday at The Annual Congress of the
Association of Anaesthetists of Great Britain and Ireland.
Pandit dubbed this state dysanaesthesia, and said the
evidence that it exists comes partly from a recent study, in which 34 surgical
patients were anesthetized, and had their whole body paralyzed except for their
forearm, allowing them to move their fingers in response to commands or to
signify if they are awake or in pain during surgery.
One-third of patients in the study moved their finger if they
were asked to, even though they were under what seemed to be adequate
anesthesia, according to the study
led by Dr. Ian F. Russell of Hull Royal Infirmary in England and published
Sept. 12 in the journal Anaesthesia.
"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.
Normally, while patients are under anesthesia, doctors
continuously monitor them, and administer anesthetic drugs as needed. The goal
is to ensure the patient has received adequate medication to remain deeply
unconscious during surgery. However, it is debated how reliable the
technologies used during surgery to "measure" unconsciousness are.
"We don't have a model for consciousness," Pandit
said. "It is very difficult to design a monitor, to monitor something you
don't have a model for.
The study of 34 patients was aimed at investigating whether
patients are fully unconscious when the monitoring technology commonly used in
the operating rooms indicates so. The researchers kept patients' arms separated
from rest of the body, which was receiving routine paralyzing drugs, by
blocking the blood supply. Patients were able to move their arm if they were
still conscious.
In the patients who responded to the doctor's command by
moving their hand, the doctors took it as a sign of consciousness, and
increased the anesthetic dose.
However, Pandit argues these patients were not
"conscious." The fact that patients only responded to command, and
didn't move spontaneously, shows their state of mind is different from normal
consciousness, he said.
The idea of a third state of consciousness may explain the
discrepancies in the reported prevalence of awareness during surgery, Pandit
said. Previous surveys have shown that when patients are asked if they recalled
being aware during surgery, about 1 in 500 will say they did. In contrast, a
recent national survey in the United Kingdom, in which patients were not
directly asked about awareness during surgery, 1 in 15,000 patients
spontaneously reported they were aware during their surgery. Only 1 in 45,000
reported pain or distress during their surgery.
Together, these statistics suggest there's a state in which
patients are aware but not reporting it, perhaps because it is an acceptable
and neutral experience for them, Pandit said. They may be aware of their
surroundings to some extent, but not concerned by this knowledge, especially
because they are not in pain.
Pandit's hypothesis may serve as basis for developing
anesthesia monitors in the future, he said. Although the state of
dysanaesthesia seems harmless, it could be a precursor to unpleasant awareness
during surgery that doctors, and patients, wish 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," he said.
Source;
http://www.nbcnews.com/health/strange-new-state-consciousness-could-exist-surgery-patients-4B11217250
No comments:
Post a Comment