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Comment by zoba | Hacker News Reader

Wouldn't your heart rate increase to alarming levels?

If you were awake & in pain during surgery, you would (of course) freak out. Even if you were paralyzed, your heart rate would increase and the doctors would know. This is what a doctor once told me when I asked.

I'm not sure how to contrast that with what the article says.

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Yes. The anesthetist is monitoring the patient's vital signs, and one of the things they are watching for are elevations of the heart rate, indicating inadequate sedation.

This isn't foolproof though. Not everyone will have the same physiological response, and over the course of an hours long procedure (during which nothing happens in the "routine" case), it's easy to lose focus and perhaps not notice a change for a little while...

Especially in the case of an intubated patient with neuromuscular blockade, I don’t think an EKG would be useful. You’re already going to have all kinds of fluctuations from the anesthesia, muscle relaxants, analgesics and just from the intubation. I’ve read about the use of EEG [1] as a way to detect awareness, but it has serious limitations. Most of all though, many anesthetic agents have a profound effect on the autonomic nervous system, and I don’t think your body would react as it would if you were conscious. You probably wouldn’t have a significant increase in heart rate, you’re already not breathing on your own, you probably wouldn’t sweat or cry either.

[1] https://twin.sci-hub.se/5746/9679b963c5859d4991d906fef74c0b7...

Paralytics used in surgery impact voluntary muscle control only, they have very little in the way of effect on things like heart rate.

Heart rate is absolutely monitored closely during surgery (precisely because it can be an indication of inadequate sedation).

Paralytics primarily effect voluntary muscles (and spontaneous respiration), but GA impacts the autonomic system to varying degrees. The blockade will keep you from moving (or breathing), the GA will depress your autonomic functioning. Now it’s true that the anesthesiologist will monitor your heart, but they have to interpret the cause of any change. If they don’t realize that the change in heart rate is due to awareness, you’re screwed.

Just my experience, but I didn't wake up during the surgery; I had a surgery with half of my body paralyzed. My vital signs remained stable (in particular, heart rate <= 60 and blood pressure 120/80). I was exceptionally fit at that time, I am sure that helped somewhat.

I was watching the whole surgery live, so to say, but I was also a little bit sedated. Felt no pain, though.

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