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You are here: MEDICA Portal. Our Topics in 2009. Topic of the Month September: Intensive Medicine. Neurology.

„A State Between Almost Awake and Deep Sleep“

„A State Between Almost Awake and Deep Sleep“

Photo: A closed eye

Dirk Rüsch is an anaesthetist at the university hopsital Gießen-Marburg in Germany. The expert talked to about inappropriate terminologies, patients participating in breathing and that nobody really knows how the issue with unconsciousness and drugs really works. Mr Rüsch, how does it feel when one experiences an artificial coma?

Dirk Rüsch: I don't know since I have not experienced it myself. After waking up from an artificial coma, patients typically only know that they have been asleep. What is an artificial coma?

Rüsch: First of all, I would like to make a remark regarding the terminology "artificial coma". It is one of the many terminologies, especially in Germany, that have been chosen inappropriately. People after all primarily associate something negative with a coma, a state of not being able to wake up due to disease. That is of course not very pleasing. Therefore, an artificial coma should rather be called an artificial sleep. If possible, I try to avoid this terminology when talking to patients and switch to other words. You are saying that the artificial coma has nothing in common with an illness-related coma?

Rüsch: No, an artificial coma generally has nothing in common with a coma. A coma is a state where the central nervous system prevents a person to be woken up through stimuli as well as to react to them adequately. An artificial coma on the other hand is a kind of sleep or a sedation - a decrease in being awake -, that has been caused by drugs and this kind of sleep can be ended at any time. Of course, it is possible to sedate a patient with severe injuries such as a traumatic brain injury so much that it is not possible to wake him which then is similar to a coma. However, as soon as the doctor wants to end this state it is possible to reverse the state by decreasing the drugs. That basically means that it is possible to control the level of this artificial sleep.

Rüsch: Depending upon the amount and type of drugs that an anaesthetist applies, the patient will be in a state between almost awake and deep sleep. Why do medics use artificial comas?

Rüsch: They use them to reduce consciousness and to make diverse intensive medical procedures, like artificial respiration, endurable for the patient. Moreover, as a result of the brain’s dormancy, the heavily stressed body is able to relax. Do physicians use comatoid sleeps often?

Rüsch: Patients have been sedated less frequently for the last ten years. Physicians want patients to be more awake which allows them to participate in artificial respiration, for example. Meanwhile, physicians know that specific disease patterns can be treated better when people are not highly sedated. Why?

Rüsch: In the past, patients were highly sedated and drugs for muscle relaxation were given. As a result, patients were not able to move their muscles and in consequence suffered from muscle atrophy. It is the same thing with bed-ridden people getting thin legs because of the atrophy of their legs muscular system. If the patient is only low sedated, he will be able to participate in artificial respiration or in physiotherapy which counteracts muscle athropy. Which kind of drugs do anaesthesiologists use for an artificial coma?

Rüsch: We use a lot of drugs which we also use for the conventional anaesthesia. Is there no difference between an anaesthesia and an artificial coma then?

Rüsch: There is no universal standard definition of anaesthesia or artificial coma. However, we can describe the conditions we achieve by anaesthesia, amongst others the absence of pain, unconsciousness, amnesia or relaxation. There are diverse kinds of anaesthesia but they always have one thing in common: the patient is more or less unconscious. This also applies to artificial comas. This is the minimal consensus. That is an anaesthesia is taken as a basis for an artificial coma. Researchers still do not know how an anaesthesia really works although it belongs to the daily medical practice all over the word.

Rüsch: Well, an anaesthesia is, like indicated before, not an entity. Meanwhile, it has been found out how heavy pain killers work and what is responsible for muscle atony. But we only have fragmentary knowledge about the elimination of consciousness and amnesia. Physicians use anaesthetic drugs without knowing how they work in detail. Researchers only slowly find out how these drugs work in the body. In the last years it became evident, that some inravenously administered drugs work at specific receptors and not at the lipid membrane of neurons which was assumed for a long time. However, there is still need of further research in order to develop drugs working more specific and have less side effects.

The interview was conducted by Wiebke Heiss


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