This was my case a few weeks ago. I changed quite a few details (including the fact that I had no help around) just to make it sound a little more prehospital scenario-ish.
The problem was......wait for it........a
cholinesterase deficiency, and the resulting prolonged neuromuscular blockade from succinylcholine!
Some degree of cholinesterase deficiency or dysfunction is present in around 1% of the general American population (considerably higher or lower in some ethnic groups) but only a few percent of
that group has such a degree of dysfunction that it results in clinically significant prolongation of paralysis from succinylcholine. Many anesthetists go their entire career without seeing such a dramatic example as this one.
Most patients who have this do not know it until they undergo anesthesia with succinylcholine. This patient, for instance, had undergone several procedures in the past, but it's likely that he never had sux before. When he said "I wake up slowly from anesthesia" (lots of people say that and it isn't true), I'm very confident this was not what he was talking about. If this had happened before, he would have had it explained to him and been tested before now.
So here's what happened:
- Up until the wake-up, this case was very routine - everything from the pre-op to the block to the induction to the surgery itself. All the drugs and doses that I listed are what I actually gave and are my standard for a case like this, and 99% of the time my patients wake up easily and are very comfortable. The only thing slightly remarkable here was that his airway was MP 3 and he had a large neck, so I Glidescope'd him. No problems there.
- He never breathed during the case. I usually get them breathing on PSV not too long after induction, but he never did, and that's not a big deal or that unusual, so I thought nothing of it.
- After the case ended, when the gas was completely off and he should have been breathing well and responding, he was breathing extremely fast and shallow and was very hypertensive and was not responding at all. This was the first time that I knew something was really wrong, and I started working through differentials in my head. Gas is off - check. Flows are up - check. Narcotized? Nope - all he got was the 100 mcg of fent on induction. Local anesthetic toxicity? No; he got bupivacaine, which tends to case cardiovascular collapse. Worst-case in my mind was an intra-op stroke. He also had twitching movements in his extremities that I was afraid was seizure activity. I treated his hypertension and the twitching movements didn't stop. I considered giving versed but decided against it; his Sp02 was 100 and I figured I'd dose him with propofol in a couple of minutes if it didn't stop. A stroke seemed extremely unlikely, though. MH crossed my mind a couple times, but his Etc02 was normal and his temp was only slightly elevated. I had the OR nurse check his BG - 140. I then called for the i-Stat to check a sodium.
- About this time, the charge MDA walked by and poked his head in the door and said "you guys about to come out?" and then when he saw the patient still intubated and I was still assisting his ventilations he said "do you need anything?" I told him to come in and explained the problem. He immediately said "he looks like he's still paralyzed - didn't you reverse him?" I explained that he had never gotten a non-depolarizer - just the tiny defasiculating dose 90 minutes ago at this point. MDA wondered if maybe the 100 of sux I'd given him wasn't actually roc. I didn't in fact draw up the drugs for this case, but the likelihood of that seemed low. Even if that had happened, it should have worn off by now. I hadn't checked his twitches ever, because, again, I'd never given him anything long-acting. Residual paralysis post-op is actually not that uncommon - I'd seen weakness a handful of times, but never like this - but it almost always happens in someone who was inadequately reversed after several doses of a long-acting non-depolarizer. Anyway, I checked his twitches, and he had 4 weak twitches with tetany. MDA wanted to reverse the guy, thinking that he definitely looked partially paralyzed, and knowing that measuring twitches isn't always 100% reliable. I was very reluctant because I was not at all convinced we were on the right track, but at that moment I couldn't think of any reason not to try, so I agreed. Gave the guy a dose of edrephonium and....nothing.
- About now, one of the other CRNA's wandered in. "What are you guys screwing up?" he asks. We explained the situation and he says "sounds like a cholinesterase deficiency to me - you didn't reverse him, did you?" Crap. We hadn't thought of that.
- Knowing that the other CRNA was probably right about a cholinesterase deficiency - and also knowing that the reversal we just gave would prolong his weakness even more, I turned on the sevo at a low concentration to provide sedation, started the ventilator, and just waited. About 2.5 hours later I tried a 4th time to wake him up, and he was extubated successfully. We then watched him in PACU for several hours. MDA explained everything to the patient in detail, called the guy's primary, and wrote him a letter explaining what happened and strongly recommending that he avoid succinylcholine and get tested for a cholinesterase deficiency.
- Two weeks later the guy calls and tells us he got tested.....he had a dibucaine number <30
This was a great learning experience for me as a newer CRNA. I wished I had recognized much quicker that he had residual paralysis, but he just didn't look like the floppy patients I'd seen before. I also wish I'd thought a little harder about what 4 weak twitches meant in someone who'd gotten sux and was still weak a long time later, but like I said, this just wasn't something that you see.....it was one of those things that you have a hard time thinking of because it's so uncommon.....but as soon as someone else mentions it, you want to slap yourself for not thinking of it.
Anyway, I know we don't test twitches in EMS, and I know we don't usually wake people up......but if we are giving sux I think it's important to keep in mind how it works and how it's metabolized and what can go wrong with it. I vaguely remember hearing about cholinesterase deficiency when i first learned about succinylcholine years ago as a new paramedic, and just not worrying about really understanding what it meant, because it just didn't seem relevant.
Hope you guys found this interesting.