seamonkey

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So, I tried mixing 10ml of ketamine with 100ml of propofol the other day. as I was doing it, I thought to myself "this won't work, its like mixing oil and water", ans sure enough the two separated just like vinagrette. I brought this to the attention of my attending, who noted that they normally mixed a more concentrated 1ml ket/100ml prop combo, and had never seen this problem before. However, they were mostly using the 1/100 mix, so they admit that a 1ml dose floating on the top may have been overlooked.

It turns out that we had suddenly changed from the Diprivan version ("ask for it by name") to the generic version, and a poll of other attendings turned up no other reports of this occuring with the brand-name.

Makes me wonder it the patients getting Ketofol weren't really just getting only propofol the whole time (untill the end, when they suddenly got a whopping dose of ketamine for dessert)

There is a benzyl alcohol preservative difference between the Diprivan and generic versions.....but I wonder if that is enough.

I mean, why would ketamine, dissolved in what I believe to be a polar solvent, mix with propofol, which is a lipid emulsion? Why would the benzyl alcohol preservative make a diff? Why does everyone say this works in the first place? To me it is totally counter-intuitive.

Does anyone here have any experience with this?
 

maceo

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So, I tried mixing 10ml of ketamine with 100ml of propofol the other day. as I was doing it, I thought to myself "this won't work, its like mixing oil and water", ans sure enough the two separated just like vinagrette. I brought this to the attention of my attending, who noted that they normally mixed a more concentrated 1ml ket/100ml prop combo, and had never seen this problem before. However, they were mostly using the 1/100 mix, so they admit that a 1ml dose floating on the top may have been overlooked.

It turns out that we had suddenly changed from the Diprivan version ("ask for it by name") to the generic version, and a poll of other attendings turned up no other reports of this occuring with the brand-name.

Makes me wonder it the patients getting Ketofol weren't really just getting only propofol the whole time (untill the end, when they suddenly got a whopping dose of ketamine for dessert)

There is a benzyl alcohol preservative difference between the Diprivan and generic versions.....but I wonder if that is enough.

I mean, why would ketamine, dissolved in what I believe to be a polar solvent, mix with propofol, which is a lipid emulsion? Why would the benzyl alcohol preservative make a diff? Why does everyone say this works in the first place? To me it is totally counter-intuitive.

Does anyone here have any experience with this?
why on gods green earth are you mixing ketamine with propofol to begin with?
 

BobBarker

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A neuro guy I know does TIVA with Ketamine and Propofol. Runs a Precedex drip also.
 

coprolalia

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Don't worry. JCAHO is going to outlaw admixing, unless you are a phamacist. If you admix yourself, you will be fired, stripped of your license, and thrown in prison. So, this immiscibility is basically a non-issue. And I promise tou that no pharmacist is goint to make "Ketafol" for you unless you show them two dozen peer-reviewed papers saying its okay... and a note from your mom.

-copro
 

pgg

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why on gods green earth are you mixing ketamine with propofol to begin with?
Are you kidding? Have you really never heard of this?

for what reason do you do it?
Because ketamine infusions are sometimes useful. For those cases in which a propofol infusion might also be useful, it's convenient to only have one syringe, one pump, and one line to deal with.
 

maceo

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Are you kidding? Have you really never heard of this?



Because ketamine infusions are sometimes useful. For those cases in which a propofol infusion might also be useful, it's convenient to only have one syringe, one pump, and one line to deal with.
can you tell me a case where a ketamine infusion would be more beneficial to a propofol infusion?
 

sevoflurane

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can you tell me a case where a ketamine infusion would be more beneficial to a propofol infusion?
Ketamine will increase the amplitude of your SSEP's. Neuromonitoring people love it. Propofol has no analgesic properties. 1/2 life of ketamine is like 2.5 hours. Great analgesic. No respiratory depresison. Potentiated by magnesium and propofol. Comfortable patients. You need to know when to turn off your infusion however, I do so about 45 minutes before the end of the case. For ortho I mix 100mg of ketamine into 1000 mg of propofol (will last me all day). Run a low infusion with 1/2 a MAC of desflurane and good regional block. 4gm of Magnesium + LMA. No narcs. The patients are supper comfy and have great wake ups with prolonged analgesia from Ketamine.
 

Bertelman

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Ketamine will increase the amplitude of your SSEP's. Neuromonitoring people love it. Propofol has no analgesic properties. 1/2 life of ketamine is like 2.5 hours. Great analgesic. No respiratory depresison. Potentiated by magnesium and propofol. Comfortable patients. You need to know when to turn off your infusion however, I do so about 45 minutes before the end of the case. For ortho I mix 100mg of ketamine into 1000 mg of propofol (will last me all day). Run a low infusion with 1/2 a MAC of desflurane and good regional block. 4gm of Magnesium + LMA. No narcs. The patients are supper comfy and have great wake ups with prolonged analgesia from Ketamine.
1) Why would you run des at .5 MAC for the duration of a general anesthetic? If you're running .5 MAC, you should be able to titrate a smooth wakeup with any inhalational.

2) Why do you even need the propofol infusion if you've got an inhalational?

SSEPs are all fine and good, but I don't imagine you are running those on your average ortho case, or any case involving an ortho attending.
 

sevoflurane

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1) Why would you run des at .5 MAC for the duration of a general anesthetic? If you're running .5 MAC, you should be able to titrate a smooth wakeup with any inhalational.

2) Why do you even need the propofol infusion if you've got an inhalational?

SSEPs are all fine and good, but I don't imagine you are running those on your average ortho case, or any case involving an ortho attending.
1) The word "Titrate" implies either use of Narcs which can = N/V, urinary retntion etc, or incresing your Mac requirements with Inha. agents = N/V, right and downshift of your C02 response curve, etc... (no effect with ketamine and only shift to the right with propofol)

2) Propofol potentiates ketamine. You can give a lot less ketamine and avoid it's own set of problems if you hit up different receptors (gaba, glutamate etc...)

I didn't say I use ketamine for SSEP in an ortho case. I use the above for big ***** fusions, harrington rods, etc. If your baseline SSEP's are crapy, ketamine will beef them up so that you have a new baseline to compare. Ketmaine is the ONLY drug available that will do this without increasing latency.


In my experience not all anesthetics are created equal and I prefer the above for my ortho cases. Anesthesia is 1/2 art in my opinion. That is why I like it so much. If you run 1/2 MAC + versed and fentanyl for cases and that is what you prefer, that is all good. Definately nothing wrong with that.
 
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pgg

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can you tell me a case where a ketamine infusion would be more beneficial to a propofol infusion?
I use propofol with 2 mg/ml ketamine for MAC cases sometimes - things like D&Cs, colonoscopies. It's opiate sparing and (just as important IMO) a bit of ketamine tends to keep them nice and still while using less propofol. They wake up briskly and totally satisfied.

It's safe, it's easy, it's very effective, the patients like it, and the surgeons like it. It's one of a dozen safe and effective ways to do those cases.

You know maceo, you might want to consider approaching discussions on these forums with less of a scornful "that's stupid" attitude and this transparent obnoxious pretense of "not understanding" why all of us morons are practicing anesthesia wrong.
 

maceo

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lol:laugh:

Since you obviously are being a tool, I am going to ignore you:sleep:
im not being a tool. ive been out of residency for a bit now but Ive never ever had to say hey where is that ketamine when i need it? but i know crnas mix that **** all the time when they are doing like an upper endoscopy or something... ketamine in my eyes is a evil drug. the only two times i will ever use it is for cardiac tamponade induction and maybe dressing c hanges in the icu. an infusion is anathema dude... stop using ketamine you crazy mot ......f........
 

Trisomy13

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why is it an "evil" drug? :rolleyes: the scary nightmares? emergence delirium? every drug at our disposal has its role in the proper setting.

i've used it in cases more than a few times with no ill effects. for that matter, i had it used on me for a procedure in an ED years ago, and then again as a guinea pig in a psychiatry research project in grad school. i can tell you from those two experiences that it has the potential to be a very useful drug in the right population - basically i would hesitate to give it to anyone with anxiety or obvious psych issues. and i would pay psych guinea pigs more than $30. :laugh:
 

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im not being a tool. ive been out of residency for a bit now but Ive never ever had to say hey where is that ketamine when i need it? but i know crnas mix that **** all the time when they are doing like an upper endoscopy or something... ketamine in my eyes is a evil drug. the only two times i will ever use it is for cardiac tamponade induction and maybe dressing c hanges in the icu. an infusion is anathema dude... stop using ketamine you crazy mot ......f........

and may we all, recent graduates, ask WHY?

I have used ketamine a lot - including my previous life and had never seen any emergence deliriums. More even - I've had ketamine myself twice and so did my son. But it was never ever used as a solo anesthetic either.
 
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2win

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and may we all, recent graduates, ask WHY?

I have used ketamine a lot - including my previous life and had never seen any emergence deliriums. More even - I've had ketamine myself twice and so did my son. But it was never ever used as a solo anesthetic either.
Boys and girls - ketamine is a wonderful drug!
I used it for sedation, general anesthesia, post op pain , RSD or whatever CRS...
What's the problem? I don't get it....
 

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I've heard of mixing 'white lightning' - propofol + ketamine + midazolam, but why not just run separate infusions? You get no issues with immiscibility and you have better ability to titrate the drugs independently. Why lock yourself into a particular ratio between your propofol and ketamine when there is really no benefit to doing so? Seriously, setting up a syringe pump isn't time consuming.
 
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Stitch

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We're using ketamine more and more in the peds ER, occasionally after a dose of versed, but often alone. It's great for shorter painful procedures, or bone reductions, and I've found it useful for intubating an asthmatic or other kid with an airway issue or even the congenital heart kids that come through.

The only problem that's come up (and I haven't experienced it) is rarely laryngospasm, so I'm a little wary of using it for oral procedures such as minor maxillofacial procedures done in the ER. That said, we've just got access to propfol, and my partners describe good experience mixing the two as described above to make 'ketafol' for those types of things. Our PICU guys are saying the same thing.

Just my thoughts coming from another perspective. I do understand adults are quite a bit different.
 

pgg

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I've heard of mixing 'white lightning' - propofol + ketamine + midazolam, but why not just run separate infusions? You get no issues with immiscibility and you have better ability to titrate the drugs independently.
I wouldn't run 3 in one syringe. I had one attending in residency who liked to mix propofol, ketamine, sufentanil, and midazolam in one syringe, but I didn't like that technique much, for most of the reasons you bring up.

I've never had immiscibility issues with ketamine and propofol.

Why lock yourself into a particular ratio between your propofol and ketamine when there is really no benefit to doing so?
I've found that the 1:5 ratio of ketamine : propofol is just about right for all the cases I use it for. I'm always titrating the infusion to effect anyway, without specific pre-preprocedure goals for total doses. It's not like I'd have a really compelling reason to keep the propofol at 50 mcg/kg/min and change the ketamine from 10 to 6 or 15.

Seriously, setting up a syringe pump isn't time consuming.
No, but setting up two is more time consuming than setting up one. Then I've got to put a stopcock in there, or use our Y-tubing that adds 10-12" of dead space to the line for each extra infusion (at low infusion rates this makes a difference).

1:5 ketafol just works, it's fast, it's easy.


I also do background ketamine infusions on most of my chronic opiate using patients having painful surgeries ... especially spines.


And long ago, I cut off a guy's hand in a tent in Afghanistan using ketamine ... not particularly proud of that anesthetic in retrospect, but it worked.


Ketamine is a great drug. Aside from using methadone (which I use sometimes, but it carries its own set of issues), it's the only practical way to hit the NMDA receptors.
 

sevoflurane

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Interesting story. Give me lots of versed with that k for an arm amp.

How do you use methadone and in what circumstances. I have very limited experience with personally administering it. NMDA antagonism is an iteresting profile for a narcotic.
 

pgg

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Interesting story. Give me lots of versed with that k for an arm amp.
Yeah, I didn't have any Versed. :oops: The story's buried in this thread over in the milmed forum, as we were discussing the sub-optimal things GMOs in the military do when they're deployed after their PGY1 years. It's not exactly a shining example of how it should have been done, but that was during my pre-residency days and I, uh, didn't know any better.

How do you use methadone and in what circumstances. I have very limited experience with personally administering it. NMDA antagonism is an iteresting profile for a narcotic.
Usually 10-20 mg of methadone IV at the start of the case depending on how narc tolerant they already were. No more methadone intraop or postop, just judicious titrating of fentanyl, realizing that the methadone I gave up front wouldn't fully kick in for several hours. I've used it maybe a dozen times, always for longer painful cases in chronic opiate users (almost all were 6+ hour spines). Basically the same patients I use light background ketamine infusions for. The upside to the methadone is that its NMDA effects last a lot longer than ketamine's. The downsides were mainly inconvenience (had to go get it from the main pharmacy) and I didn't get to use it much in the last year because I had a streak of attendings who didn't want to use it at all, or had reservations about sending them to unmonitored beds postop because of its kinetics.
 

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I use propofol with 2 mg/ml ketamine for MAC cases sometimes - things like D&Cs, colonoscopies. It's opiate sparing and (just as important IMO) a bit of ketamine tends to keep them nice and still while using less propofol. They wake up briskly and totally satisfied.

It's safe, it's easy, it's very effective, the patients like it, and the surgeons like it. It's one of a dozen safe and effective ways to do those cases.

You know maceo, you might want to consider approaching discussions on these forums with less of a scornful "that's stupid" attitude and this transparent obnoxious pretense of "not understanding" why all of us morons are practicing anesthesia wrong.
ketamine for colonoscopies? seems like overkill, doesn't it? propofol alone works fine for me. for EP lab cases, i'll bolus 0.3mg/kg ketamine and start ketofol infusion (1 mg K:10 mg prop mix).