ketamine and WPW

[dfk]

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i had a case today of an 18 y.o. fem with WPW/SVT hx for ablation.. in general (and short), ketamine and prop gtt with whiffs of benadryl/fent worked well(for the most part). as i got to thinking, giving (low dose = 30 mg in 25-30 ml prop) ketamine may worsen (or risk) WPW-esque result intra-EPStudy. just wondering, what you all think in this case.
FWIW: there were only three times over 6 hrs that she was "off the hook" for a minute until prop bolus was jammed.. i ended up using 3400 mg of prop, 37.5 of benadryl, 650 mcg fent and 6 of midaz. my question is (and the literature is split in my quick search), would any of you care less to use ketamine in say, 1 mg/ml of prop? i was just (perhaps uneducatedly) concerned about introducing a re-entrant tachy (or non-re-entrant tachy). thoughts?

 

[urge]

You know the cardiologist will induce svt. What is your concern? Making their job too easy?

BTW, why do you use so many drugs for a simple case? 650 of fentanyl for 2 sticks in the groin, seriously?

 

[stone123]

How beneficial is ketamine added to propofol for MAC/sedation cases. Some like to use it often, others never. Do the benefits outweigh the side effects/potential side effects? Just curious. I use it in some situations, but most of the time get along fine without it.

 

[huktonfonix]

How beneficial is ketamine added to propofol for MAC/sedation cases. Some like to use it often, others never. Do the benefits outweigh the side effects/potential side effects? Just curious. I use it in some situations, but most of the time get along fine without it.

depends what side effects you are worried about. The benefit is that since propofol is not analgesic, the ketamine provides you with some analgesia and supposedly maintains spontaneous ventilation better than narcotics. I personally feel its not needed in nonstimulating procedures or procedures where the surgeon has blocked the site well. For a continuously stimulating procedure I find it more useful in the appropriate patient. Of course, I can usually get the same result with well titrated narcotic and propofol.

 

[plants]

this is a good article about the comb for MAC

http://www.anesthesia-analgesia.org/cgi/content/abstract/90/4/858

 

[Noyac]

I never looked at the person posting this and just jumped right into the thread. As I was reading I was thinking 😱 look at all the drugs. I don't think polypharmacy adds any benefit in this case. Then I saw the benadryl and immediately thought, nurse. No offense, I know there are a hundred ways to skin a cat. Personally, I would have just used propofol.

 

[ChrisA]

Hey Noy


Why dont you like benadryl ? The person who taught me to use it in anesthesia (and i think its a nice adjunct) was an attending who I see as an awesome anesthesiologist and my mentor.

(For this case, i dunno but just asking your opinion about it in general)

I never looked at the person posting this and just jumped right into the thread. As I was reading I was thinking 😱 look at all the drugs. I don't think polypharmacy adds any benefit in this case. Then I saw the benadryl and immediately thought, nurse. No offense, I know there are a hundred ways to skin a cat. Personally, I would have just used propofol.

 

[Licoricestick]

Hey Noy


Why dont you like benadryl ? The person who taught me to use it in anesthesia (and i think its a nice adjunct) was an attending who I see as an awesome anesthesiologist and my mentor.

(For this case, i dunno but just asking your opinion about it in general)

Sorry....benadryl? Is this the same thing over there as what I'm used to (diphenhydramine - sedating antihistamine)?

I've never seen or heard of this being this used over here (although I'm discovering quite a few intercontinental differences in anaesthesia on this forum). Do you use it for the side effects (eg premed for antimuscarinic effects)? What sort of doses? What's the benefit over propofol/benzo/opioid?

 

[Arch Guillotti]

The whole benadryl thing seems kinda weird to me. I have never even considered using it in the OR except for an allergic reaction.

 

[ChrisA]

Hey

Well, this attending (who is da bomb seriously) taught me to use it this way.

Obviously there are some sedative effects (as everyone knows) and they are more pronounced in the elderly.

I was doing a knee where i had done the standard fem blk then spinal and MAC. There were some minor pressure issues even on a prop drip of 50. Not much and not enough to keep this patient comfortable. Didnt really want to give any narcotics since this knee guy is fast. So attending comes in and we are talking about the situation. After going through some of the drugs we had avaliable he asks what I think about benadryl (i acted the same way everyone here has) and he suggests I try 50.

So i give the 50 IV and the patient drifts off nicely to sleep on a 25 mcg prop drip, no narcs and wakes up happy at the end of the case. Avoided all the BP issues and adding more polypharmacy to the mix just by using a little squirt of benadryl. I thought it was genious and have used it in that similar way (with old folks and MACs) every since.

Try it see what yah think. Does not work well on the younger folks (for obvious reasons) but great on the elderly.

 

[proman]

I've seen GI and pulmonary guys use it when they do their sedation (without us). Normally give midazolam, fentanyl, and diphenhydramine. It's a dirty drug, has a lot of side effects with unpredictable effects. Sure you can use it but why? We have much better drugs.

 

[ChrisA]

Well it is in many OTC sleep aid for its sedative effects. So it isnt like using it is taking any significant risk. Sure, its an H1 blocker and has anticholinergic effects but at low doses it has a pretty safe profile.

just another tool in the toolbox

I've seen GI and pulmonary guys use it when they do their sedation (without us). Normally give midazolam, fentanyl, and diphenhydramine. It's a dirty drug, has a lot of side effects with unpredictable effects. Sure you can use it but why? We have much better drugs.

 

[Noyac]

Chris A, instead of us telling you why we don't like it. Why don't you tell us what it is doing for you beyond the sedation. Give us the pharmacologic definition b/c we are physicians and we don't give anything without knowing exactly what it is we are giving and why.

 

[ChrisA]

I doubt I need to explain benadryl to anyone here. I could spout it all off but what exactly is the point?

 

[OB1🤙]

My problem with benadryl and elderly folk is that I don't like having to order stupid tests when they get delirious (granted, my experience with this is in inpatients, but still).

 

[Licoricestick]

Chris A, instead of us telling you why we don't like it. Why don't you tell us what it is doing for you beyond the sedation. Give us the pharmacologic definition b/c we are physicians and we don't give anything without knowing exactly what it is we are giving and why.

please do!

 

[ChrisA]

Ok.

I was just mentioning the reasons for concern (tho not likely with one IV dose of 25-50).

What exactly are you looking for me to say? Im not going to waste time discussing how the drug works, that is homework anyone can do. It seems pretty clear to me how it is useful in the situation I described....

 

[Bertelman]

Well it is in many OTC sleep aid for its sedative effects. So it isnt like using it is taking any significant risk. Sure, its an H1 blocker and has anticholinergic effects but at low doses it has a pretty safe profile.

just another tool in the toolbox

I'm not sure I would be so confident saying that.

 

[dfk]

You know the cardiologist will induce svt. What is your concern? Making their job too easy?

BTW, why do you use so many drugs for a simple case? 650 of fentanyl for 2 sticks in the groin, seriously?

unfortunately the case wasn't all that easy. this girl (18 yrs old) had a case cancelled prior b/c she couldn't tolerate the procedure. so, she came back in the attempt to be successful with ablation. none the less, she was told that she was jumping off the table the first time.
aside from the stimulating points (3 sticks: one in subclavian, two in groin), what really got her is when isuprel was running and her HR was maintained at 240-ish. she just couldn't get comfortable. i've had good luck with prop and ketamine in the past for EPS procedures, but wasn't sure if there was a contraindication to use ketamine here.
so, i gave her whiffs of benadryl (12.5 mg) and fentanyl (25-50 mcg) along with prop during the procedure.
six hours later, ablation was still unsuccessful.

thanks for the replies guys!

 

[Noyac]

unfortunately the case wasn't all that easy. this girl (18 yrs old) had a case cancelled prior b/c she couldn't tolerate the procedure. so, she came back in the attempt to be successful with ablation. none the less, she was told that she was jumping off the table the first time.
aside from the stimulating points (3 sticks: one in subclavian, two in groin), what really got her is when isuprel was running and her HR was maintained at 240-ish. she just couldn't get comfortable. i've had good luck with prop and ketamine in the past for EPS procedures, but wasn't sure if there was a contraindication to use ketamine here.
so, i gave her whiffs of benadryl (12.5 mg) and fentanyl (25-50 mcg) along with prop during the procedure.
six hours later, ablation was still unsuccessful.

thanks for the replies guys!

OK, I'll stop being an arse and answer your question as I see it but I am still waiting for ChrisA to explain what it is about benadryl he likes so much and why he uses it instead of the other drugs that are made to achieve his goal with less SE's. As far as a contraindication to use ketamine in WPW I don't necessarily see one in the doses used for sedation. In larger doses I could see where there may be a problem due to sympathetic stimulation. But my point is that mixing drugs confuses the picture (I know I tout the benefits of ketamine all the time) and in this situation I'd prefer to keep it as simple as possible. Maybe you needed the K, I wasn't there.
Just my $0.02

 

[ChrisA]

Noy

As i stated. The patients I use it on (as well as many attendings I worked with) are elderly patients who do not tolerate propofol well for MAC short procedures and simply need a little extra sedation and low doses of benadryl achieves that. There are many ways to skin a cat, this is one that works well. One that has been used for 15 years by my mentor and now by myself with these specific subsets of patients.

WHAT exactly is it you want to ask me about it. Im not going to regurgitate goodman and gilman on the drug. My experience with it (over 10 years), has been excellent as an adjunct. Where I trained and everywhere ive been people (MDs and CRNAs) use this technique.

Dont like it dont use it.

 

[Noyac]

Noy

As i stated. The patients I use it on (as well as many attendings I worked with) are elderly patients who do not tolerate propofol well for MAC short procedures and simply need a little extra sedation and low doses of benadryl achieves that. There are many ways to skin a cat, this is one that works well. One that has been used for 15 years by my mentor and now by myself with these specific subsets of patients.

WHAT exactly is it you want to ask me about it. Im not going to regurgitate goodman and gilman on the drug. My experience with it (over 10 years), has been excellent as an adjunct. Where I trained and everywhere ive been people (MDs and CRNAs) use this technique.

Dont like it dont use it.

Alright then. You finally told us how you use it, in the elderly.
First of all, I haven't found an elderly person who didn't tolerate propofol. Maybe I haven't done enough though. Could you explain, "do not tolerate propofol"?

Secondly, it is the elderly that I hesitate to give benadryl to in the first place. The reasons I hesitate in this population is b/c of prolonged sedation, confusion, urinary retention, among other things. You will probably claim to see or call all your pts post-op and that you have not seen this but to that I will say, you haven't done enough.

Your right about the many ways to skin a cat. I choose my way over yours.

 

[ChrisA]

Hey Noy

the issue with propofol was that the pt's pressure would dip quickly at very very small doses. So even on the pump she would wake up and move with low pressures. Just was not getting enough sedation and could not tolerate more from a hemodynamic standpoint. Initially we treated the dips but they persisted.

Your right about the many ways to skin a cat. I choose my way over yours.

I can respect that.

 

[Noyac]

Hey Noy

the issue with propofol was that the pt's pressure would dip quickly at very very small doses. So even on the pump she would wake up and move with low pressures. Just was not getting enough sedation and could not tolerate more from a hemodynamic standpoint. Initially we treated the dips but they persisted.



I can respect that.

I can seriously say I have never seen the pressure drop so much and the pt still not be adequately sedated. But if I do see it then I will mix in a neo drip if necessary. The nice thing about propofol in the elderly is that it is still metabolized quickly unlike benadryl.

 

[switching2gas]

Noy

As i stated. The patients I use it on (as well as many attendings I worked with) are elderly patients who do not tolerate propofol well for MAC short procedures and simply need a little extra sedation and low doses of benadryl achieves that.

I thought as a general rule, anticholinergics are to be avoided in the elderly due to risk of delirium.

 

[proman]

Just anticholinergics that cross the blood-brain barrier, like diphenhydramine.

 

[fakin' the funk]

I thought as a general rule, anticholinergics are to be avoided in the elderly due to risk of delirium.

My understanding is, avoided in the elderly due to risk of exacerbating cognitive impairment/dementia...which may look a lot like delirium. Dementia is supposedly an ACh disorder hence the donepezil and rivastigmine.

 

[jwk]

I can seriously say I have never seen the pressure drop so much and the pt still not be adequately sedated. But if I do see it then I will mix in a neo drip if necessary. The nice thing about propofol in the elderly is that it is still metabolized quickly unlike benadryl.

Dammit Noy, I just found this thread and by the time I got to the end of it, you'd already made all the points I was thinking about posting!

Seriously though, the polypharmacy MAC concept just isn't ideal. We do a ton of long podiatry cases - they MIGHT get some fentanyl around the time of the block, and then they get a propofol drip for four hours to get all their hammertoes and bunions fixed in one sitting.

I've never understood the hoopla about propofol and old/sick folks. Just use less, give it slowly, and BE PATIENT. That's all we give for cardioversions - some of them only get 20mg.