Beta Blockade during C-section

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Pt in her early 20s had a history of "fast heart rates", not formally diagnosed by a physician. Becomes mildly symptomatic when it occurs at home... sits down until it goes away.

During c-section with SAB becomes tachycardic with HRs in the 180s. BP stable in the 110s to 120s, but pt states she is becoming dizzy and short of breath.

In my anesthesia drawer I have Esmolol, Metoprolol, and Verapamil. I also have Edrophomium and Neostigmine for those who favor a less traditional (or perhaps more traditional) approach.

Which of the afore mentioned medications would be my best bet for treating the patients tachycardia assuming vagal maneuvers had failed and why?

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I'd probably reach for the esmolol first, give her 10-20mg and see how she handles it. My reasons for choosing it are the 1/2 life (9 minutes compared to 2-8 hours for some of the other choices) and onset of action (although verapamil and esmolol are both pretty close to each other).

Verapamil would be my second choice since the heart would still be responsive to sympathetic innervation (unlike with beta-blockers) ... and it's duration of action is relatively short.

What did you choose?

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What was her pressure to start with? If they were fairly high with an acute drop, even though still in the 110's, I might think about a little phenylephrine.

Also, with the SOB, I'd be thinking about high spinal as well.

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Spinal for C-section means you’ve got at least a T4 level. It’s probably fairly safe to assume that some, if not all, of her cardiac accelerators are blocked, thus beta blockade wouldn’t be my first choice. Sounds like she might be experiencing some sort of irritable focus or re-entry phenomenon, but obviously I’d have to know more about the pt. If I didn’t have anything more, I’d probably reach for verapamil. I would think that if her tachycardia subsided, as it often does at home, that I might hose myself giving a cholinergic agonist. If she was really worked up over the dyspnea, I’d talk her through it and, if I truly believed that her cogitative state might be contributing to the rhythm, I’d consider some fentanyl.

So, how’d you handle it?

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I would probably start with some extra fluid. Of the drugs available, I would probably have gone with Esmolol as well.

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Sensory block was T4. Initial pressure was 130's.

Can anyone come up with a good idea not to use Esmolol?

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Sensory block was T4. Initial pressure was 130's.

Can anyone come up with a good idea not to use Esmolol?

Possibly fetal bradycardia? I looked at a couple of research articles (actually anecdotal case reports) of parturients receving esmolol for tachycardia, and it did state that there were reports of fetal bradycardia, but they were short lived and had no lasting effects.

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I gave the patient 15 mg of esmolol, bringing her HR back into the 130s. Ten minutes later she was again in the 180s complaining of feeling unwell, dizzy, and slightly SOB.

I was hesitant to administer a further dose of esmolol since I had learned in school that there were case reports of esmolol causing profound persistant fetal bradycardia. It's at this time that I gave the patient 1 mg of Metoprolol, which fairly quickly brought her HR into the 90s, making her previous symptoms disappear. No further episodes occurred during the C-section, the baby was delivered healthy with good apgars and a normal HR.

From the brief research I completed this previous weekend, it seems like Metoprolol might not have been the best choice since, like all extensively liver metabolized drugs, it is fat soluble and crosses the placenta easily. Propranolol has been the drug of choice in the past, since it has extensive tissue binding and therefore does not cross as readily. Another choice if available, might be Atenolol, a more water soluble drug, however, it is my understanding that IV Atenolol is not available in the US.

I was not eager to use Neosynephrine in this situation since it increases intrauterine artery resistance and therefore decreases blood flow to the placenta. The acetylcholinsterase inhibitors weren't an option to me for obvious reasons.

Open for all comments or suggestions.

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This is why OB is so challenging...you are not just treating 1 patient and you must think about how a drug that is good for mom may not be so good for the baby.

I have another OB related question, the other night, one of the new OB docs requested Methergine IV. We are taught to NEVER give methergine IV so I hesitated. I grabbed the vial and it says on it for IM/IV use. I even did a quick look up on my PDA. The Ologist that was with me meanwhile added some additional Pitocin to the bag since he wanted me to look it up first too. My PDR states IV dose slow over 60 sec. I diluted it and gave it slowly since I was unsure of it;s IV effects. What are your thoughts?

Why are we taught not to give it IV when it plainly says on the label for IM/IV use only? I have used methergine plenty of times but have always given it IM and have never had a problem.

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This is why OB is so challenging...you are not just treating 1 patient and you must think about how a drug that is good for mom may not be so good for the baby.

I have another OB related question, the other night, one of the new OB docs requested Methergine IV. We are taught to NEVER give methergine IV so I hesitated. I grabbed the vial and it says on it for IM/IV use. I even did a quick look up on my PDA. The Ologist that was with me meanwhile added some additional Pitocin to the bag since he wanted me to look it up first too. My PDR states IV dose slow over 60 sec. I diluted it and gave it slowly since I was unsure of it;s IV effects. What are your thoughts?

Why are we taught not to give it IV when it plainly says on the label for IM/IV use only? I have used methergine plenty of times but have always given it IM and have never had a problem.

Methergine IV can cause severe vasoconstriction or vasospasm which can cause ischemia to the limb the IV is in. Don't get me wrong I've given it IV as well but I've always been pretty vasoconstricted myself when I had to do it.

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Brenna's Dad,

the latest and greatest in literature is contraindicating earlier beliefs that neo causes fetal comprimise and is now considered just as safe and first line as ephedrine....

however, i work w/ many doc's and CRNA's who continue to practice w/o neo...

just a heads up...

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Brenna's Dad,

the latest and greatest in literature is contraindicating earlier beliefs that neo causes fetal comprimise and is now considered just as safe and first line as ephedrine....

however, i work w/ many doc's and CRNA's who continue to practice w/o neo...

just a heads up...

Just an old fart here - it's taken me a good while to feel comfortable with neo, but it works great, and as an expected bonus, has cut way down on those high heart rates from big doses of ephedrine.

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