Medic_9 said:
Not in med school at all, but I am a medic so I have some understanding of the body.
Would the person waking up once they recieve the signal from their nerves to their brain not increase their heart rate or blood pressure? From experience I know that people who are in pain or panicked tend to show such in their vitals. Would this not be picked up by the anesthesiologist and rectified?
I'm not saying that the person doesn't wake up, just that the problem should be caught way before the end of the surgery.
Just coming off my anesthesiology rotation, thought I'd pipe in with a few points.
Medic_9 is exactly correct. Every day in the OR I would watch heart rate and blood pressure (among other thigns), and adjust the anesthetic accordingly. Frequently this means giving bumps of fentanyl (a powerful opioid) to treat pain, even though the patient is asleap. Prolonged tachycardia is not good, and there's evidence that receptor upregulation, etc, make for more post-op pain. So we treat pain aggressively and early.
You need to understand that anesthesia requires 4 things: amnesia, loss of consciousness, paralysis, and analgesia. Inhaled anesthetics (typically sevoflorane, isoflorane, desflorane) do all 4, other drugs only do some. We do give paralytic agents (frequently succinylcholine, rocuronium, or cisatrocurioum, all i.v.) regularly for induction and often throughout the case to allow the surgeon to operate, and yes, without any other anesthetic you can't move but are very much awake and aware. That is why some people advocate giving the muscle relaxant last - so that if you loose the i.v. you don't have a patient freaking out and unable to breathe (but the surgeon would be able to operate). Amnesia is part of many anesthetic agents, most notably the benzodiazapine (typically midazolam) that we give before heading into the room. And unconsciousness can be produced by any of the anesthetic drugs we regularly use, except the muscle relaxants.
The "head monitoring thing" is a BIS monitor. My understanding is that the company that makes these, Aspen Medical, was heavily involved in the Dateline piece. It's a highly processed EEG that gives you a number 0-100, where 0 indicates no brain activity, 100 is fully awake. They say for anesthesia you typically need 40-60. There are case reports of people being at all sorts of BIS levels that don't correlate with other data - one guy was talking post-op at a BIS of 52. The thought (largely by Aspen)is that the reflexes we typically look for are mediated by spinal nerves but we have no good way of knowing what the brain is doing, and that the BIS shows us the brain. I don't exactly buy that, but there's a grain of truth to it. The BIS is just another piece of data, which (IMO) can sometimes be of benefit. I've seen many cases done without the BIS which go just fine.
My guess is that many cases of intraoperative awareness are cases where the intent was NOT to fully anesthetise the patient. Some patients are given heavy sedation for a procedure, doze off to sleep (which is fine), but wake up and think that they were supposed to be fully asleap (not their fault, the anesthesiologist should have explain things better). I had a patient this week who got a dose of midazolam, and as we were walking down the hallway into the OR she asked if she was supposed to be unconscious (the answer is no, we just used the midazolam to relax her). It's possible the drug will have interfered with her memory, and she might remember being in the OR and not asleap, and worry that she had intraoperative awareness. Now, the resident I was with was great and explained things to her every step of the way so I doubt that, but it could happen. In fact, after the procedure she was thanking everybody profusly
🙂 Just another day at the office. I love this job.
never heard about that one, thats funny!
