Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: DoctorBeaver on 10/12/2008 11:38:39
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I've seen people who have been heavily sedated and they seemed asleep to me. The same is true of full anaesthetic. So what's the difference?
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Can I add a further question here?
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Is it relevant? [:(!]
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Yes, of course, Mr Grumpy.
I don't understand the removal of the pain part. Do patients receive anaesthetic as well as a sedative? So if you undergo surgery, there is more than just being "knocked out"?
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Dunno [???]
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There is the thankfully rare phenomenon of anesthesia awareness, where a patient becomes conscious during an operation but is unable to communicate this because they have been deliberately temporarily paralysed by medication...
A common risk factor is the use of a medication that induces muscle paralysis. Under general anesthesia, the patient's muscles may be paralysed in order to facilitate tracheal intubation, surgical exposure, or mechanical ventilation. The paralytic agent does not cause unconsciousness or take away the patient's ability to feel pain.
A fully paralyzed patient is unable to move, speak, blink the eyes, or otherwise respond to the pain except through physiological signs such as increased heart rate (tachycardia), blood pressure (hypertension), dilation of the pupils (mydriasis), sweating (diaphoresis), and the formation of tears (lacrimation) in response to pain. This is because these paralytic drugs cause skeletal muscle paralysis but do not typically interfere with the functioning of the autonomic nervous system. Even though the patient cannot directly signal their distress, they may exhibit signs of awareness detectable by clinical vigilance.
Many types of surgery do not require the patient to be paralysed. A patient who is anesthetised but not paralysed can move in response to a painful stimulus if the analgesia is inadequate. This can serve as a warning sign that the anesthetic depth is inadequate. However, "moving" under general anesthesia does not necessarily correlate with awareness, nor does "not moving" under general anesthesia necessarily correlate with amnesia.
http://en.wikipedia.org/wiki/Anesthesia_awareness