Had a case about a month ago that was interesting to me and thought i would post to see what people think.

Lefort 1 osteotomy on a 28y/o healthy male about 90kg, no meds, had this procedure done 2 years prior with no issues. They used general anesthesia on the first procedure 2 years ago. He had a cousin who had MH in the past so we decided doing a TIVA was best.

He had 2mg versed, 150mcg fentanyl before hooking up monitors etc which made him a little loopy but didn't knock him out by any means. Induction he got 200mg propofol 40mg rocuronium. Nasal intubation went fine with no issues. Surgeon wants BP no more than 100 systolic. I started a propofol gtt at 200mcg/kg/min and precedex at .4mcg/kg/hr. I gave another 100mcg fentanyl couple minutes before incision. Surgeon starts working and BP is 130 systolic so i give 100mcg more of fentanyl. HR was 70-80's if i remember right. After the last dose of fentanyl i started talking about giving a beta blocker or asking about starting an esmolol gtt just to hopefully keep a nice steady level for the BP. CRNA wanted to do more narcotic and just increase our gtt's so we went with that. I increased propofol to 225mcg/kg/min and precedex was brought to .7mcg/kg/hr within 30 minutes of start time. Pt also got 2mg dilaudid 10-15 minutes after increasing the gtt's. Another 250mcg fentanyl given throughout next 30-40 minutes or so. He finally was around 90-100 systolic with all of this. Surgery was about 2.5-3hrs. I shut the precedex off 15-20 minutes or so before he was done closing and decreased propofol to 175mcg/kg/min and then turned that off as he was done closing. It took 25-30 minutes for him to come back breathing on his own. He was breathing 8/min with 500 tidal volumes but would not move or wake to any stimulus. We decided to leave him intubated and place an O-ring on the tube and hook up nasal cannula to that and take him to pacu. Gave report and by this time he was breathing 10-12/minute with good chest rise and sats mid 90's. I extubate place nasal cannula and leave the pacu. According to the MD and PACU nurse he was "comatose" for another hour before he just "woke up" they said. When we got to pacu it had been almost 2hrs since any narcotic but he had 500mcg fentanyl and 2mg dilaudid total all within first hour of surgery.
Ive asked 5 different people there opinions and so far have had several different answers. I was sure i knew the answer that day but once i got some different opinions and starting looking into the pharmacokinetics of these my answer changed. I don't know if there is a for sure answer but curious of what everyone thinks was the reason for the slow wake up...
Precedex? Propofol? Narcotic? or combo of all of them?