Expert: Ronald Levy, M.D. - 12/14/2006

Question
>Personally, I have never heard the term before nor has it >ever been a factor in anesthesia that I am aware of. That >is the purpose of anesthesia, to reduce or elimiate any >responses to surgery.

General anesthesia and/or sedatives decrease the level of the patient's consciousness so that he/she is not aware of the pain the surgery would otherwise cause. However, the nociceptors are other sensory nerves at the site of the surgery will continue to fire-off. These signal maybe not be consciously perceived but would still be detected by the autonomic nervous system and cause a significant response. I assume that the ANS's response to these signals fired-off by the nerves in the injured tissues could cause a shock-reaction. This can dangerously-alter the rhythm of the heart and possibly kill the patient.

>Obviously during times of trauma, etc., we are under a >great deal of stress which causes the release of numerous >hormones and neurotransmitters. This is probably what they >are referring to, but again, I have never heard of it.

Is there anything that can be done to prevent the release of these hormones/neurotransmitters, so that the patient under going surgery does not enter a state of shock. My guess is that all sensory receptors and sensory nerve-ending in the area that will be operated on would need to be locally-anesthetized before the surgery takes place.

From what I know, extreme pain can cause neurogenic shock even if the victim isn't aware of the pain.  

Answer
As I said before, what you describe does not happen under general anesthesia (at least not to the extent that you presume), otherwise we could never do surgery. Anesthesia intercepts the signals going to the brain that tell it to release these neurotransmitters, etc. We don't prevent the release of neurotransmitters, we reduce or eliminate their effect. In cases where we don't (like autonomic hyperreflexia) we get into great trouble if we can't control the unopposed autonomic effects. What you say about the ANS response...this does not happen in practice.

Ronald Levy, MD
Associate Professor of Anesthesiology
UTMB-Galveston