I recently had a minor operation under general anaesthetic. The procedure took around 45 mins and was carried out as day surgery.
I left my Dexcom on and pump connected the whole time. The anaesthesiologist and her assistant carefully went over the procedure for accessing my Dexcom readings on the pump screen (I am using a Vibe). I also showed them how to suspend the pump in an emergency although we then decided that it would be better simply to disconnect at the infusion set (I showed them how).
The objective was to have my BG at ~ 8 mmol/L and running flat just prior to the op. In reality I woke up at around 3.8 and even with a TB it was only around 5.8 just before surgery. The nurses and anaesthesiology team took at least 4 or 5 fingersticks in the couple of hours between arrival at the hospital and going under. My pump was set to a TB of -50% for the duration of the op.
Apart from the minor low BG beforehand, everything went like clockwork. Dexcom output sat at around 7-8 for the rest of the day - Purrfect -