It happens to me when numbing drops are put in my eyes for an exam, but it hasn't happened with any general anasthesia. Go figure.
I get nauseous, sweaty, dizzy, and I have to lie down
within a few seconds before I fall down or pass out. It is really unpleasant, and there is nothing I can do to change it. However, I have heard that a shot of atropine before the anasthetic can help prevent the response. It opposes the action of the vagus nerve and helps keep the heart rate up.