[WntrMute2]

So I've begun working with students, (the blind leading the blind). Many of them tell me they were taught not to switch muscle relaxants once they begin giving one. I claim that that's nonsense and that there is no good reason not to switch to a different non-depolarizing agent if one wishes. I do know that there are some interesting effects with mixtures but I was taught to use what's appropriate and not to be concened. I don't find aything in my text books suggesting not to switch if one wants. What is being taught out there in SRNA land and for those practicing or privy to some research, how do you practice? Also, how many of you reverse Mivacron if indicated? Yes I know that neo inhibits plasma cholinesterase but it also allows more Ach to remain at the NMJ.

[Brenna's Dad]

A few things come to mind regarding this taching.

1. I have been taught to half my dose of NDMR after using Succinylcholine, so I do not get a prolong block.

my verdict is out on this one. Clinically, the times I have used a full dose of relaxant, I can't say I have gotten any really prolong block. The times I use half the dose, I think I get a much shorter block than I would get with a full dose.

2. Do not switch between benzolisoquinolones and steriod-type muscle relaxants. Effects are unpredictable.

I have read the research on this one and would have to agree. A few weeks ago, I use Rocuronium to intubate and put the patient on a Cisatracurium drip. Despite using a full dose of reversal, I believe the patient's ensuing respiratory distress after extubation (4 twitches before doing so and with absence of fade) was related to weakness.

3. Switching between muscle relaxants of the same class.

No problem. Clinically, I don't often do this. But I wouldn't be all the hesitant to do so.

[gotosleep]

1) why would you want to reverse mivacron?

2) Aren't mivacron and succs metabolized by pseudocholinesterase and therefore not susceptible to reversal?

[jrvb]

Originally Posted by gotosleep

1) why would you want to reverse mivacron?

2) Aren't mivacron and succs metabolized by pseudocholinesterase and therefore not susceptible to reversal?

Mivacron is metabolized slowly by pseudocholinesterase but it is a non-depolarizer as well. It competitively blocks acetylcholine from activating receptors. A massive rush of acetylcholine as provided by anticholinesterases will knock off the Mivacron. However, since anticholinesterases also inhibit plasma cholinesterase, reversing to early may lead to prolonged blockade. Since it is so short acting it seems like more trouble than its worth to try and reverse it.

SUX is a true depolarizer so it is not reversed w/ anticholinesterases.

[Brenna's Dad]

My understanding regarding Mivacron, is that it can be reversed as well. Since it is so short-acting, the duration (even if prolonged with Ach-E drug), should not outlast the reversal.

[deepz]

[quote=jrvb]Mivacron ....Since it is so short acting it seems like more trouble than its worth to try and reverse it.........

At the risk of being contradicted, as I seem always to be, lately ... I've always noticed that by the time Mivacron achieves full effect, it has already half worn off.

... It's a joke. I'm sure someone out there retains a sense of humor, someplace.

Please don't turn me in to the thought police.

deepz

[Brenna's Dad]

I agree with you Deepz, I am seriously considering whether it works at all!