Stages of anaesthesia

You are feeling sleepy...

This young man is clearly in stage 1 of general anaesthesia.

There are 4 key stages of general anaesthesia, and the aim is to move seamless from stage one to stage three; skipping two and four entirely. Stages:

1. Analgesia - Things are a bit numb, and the patient is a bit woozy, but still conscious.
2. Excitement - Patient loses consiousness, but still jerks around in response to pain. You want to avoid this stage
3. Surgical Analgesia - This is the stage you are looking for. Respiration has stabilised, and they don't have any voluntary actions any more.
4. Medullary paralysis - This is particularly bad. Basically, the brain gets so suppressed that important things like breathing and having a pulse stop. It kills you in about 2 minutes, so you should try to avoid this stage with your patients.