Ketamine for Post-intubation Sedation. Experiences?

[18G]

Just looking for some experiences from providers who use ketamine for sedation in intubated patients.

I had a post-arrest patient from an ED who was receiving ketamine for post-intubation sedation. The ED obviously didn't understand this drug as they weren't dosing it every 5-15mins and they did not start a drip. The RN said, "we only had to give ketamine once", as the patient was reaching for the ETT. Go figure. I requested ketamine at 2mg/kg and fentanyl 50mcg and then dosed at 1mg/kg for maintenance sedation. The patient did not do as well with the 1mg/kg so I increased to 2mg/mg during transport. The higher dose worked much better however, with bolus dosing q10-15mins the patient did not have a smooth or consistent level of sedation and exhibited arm movement in between doses and also increased respiratory rate above the set vent rate.

Ketamine is a drug I have just started to use with my patients. I know some recommend to use ketamine with fentanyl even though ketamine has strong analgesic properties. What is the trick to achieve a smooth level of sedation while bolus dosing? I think a drip is the key but just curious if there is another strategy for bolus dosing.

Any experiences shared are much appreciated!

 

[TXmed]

I love using ketamine for post Intubation sedation, it works well when used with different drugs (propofol,fentanyl). You CAN NOT overdose someone on ketamine it just stays in the system a little longer with no ill effects. My suggestion with any post Intubation sedation is make sure you give some just prior to moving and loading. As that is when they will have the most stimulus.

Post Intubation management is alot more than just the drugs though. Reducing movement, patient position, ventilator settings all help. A patient over breathing the vent doesn't bother me as much. I would first adjust the ventilator (pressure support, rise/ramp time, trigger level, fio2, rate) all help the patients comfort level. As a patient is waking up don't underestimate how much talking to the patient helps. I also try to coban the patients thumbs together to keep from randomly grabbing the tube

 

[Carlos Danger]

There's no question that an infusion will result in more steady serum levels of the drug. With any sedative or analgesic, you'll likely find yourself giving less total dose of the drug over several hours with an infusion vs. bolus dosing. There isn't a "trick" to it, you just give a bolus and start the infusion, then adjust the infusion up or down as needed. But if you want the patient completely still, neuromuscular blockers are the best way to do it.

50 mcg of fentanyl is probably far too little to have any appreciable sedative effect in transport.

You CAN NOT overdose someone on ketamine it just stays in the system a little longer with no ill effects.

Actually, ketamine has plenty of potentially adverse effects, the risks of which increase with higher doses or faster rates of administration. Respiratory depression, loss of airway reflexes, hypersalivation, laryngospasm, seizures in susceptible individuals, and both systemic and intracranial hypertension, to name a few. It is true that the estimated LD50 requires much more ketamine (240 mg/kg) than you probably even have have available, but that doesn't mean that you can't give someone too much of it.

 

[jwk]

What do your hospitals use for post-intubation sedation? My guess is ketamine isn't it. And if you don't understand that there are tons of side effects associated with ketamine, you probably shouldn't be using it.

 

[NomadicMedic]

My service does a fair amount of vented community hospital to level 1 IFT and I've not seen Ketamine used in the post RSI sedation package. It's usually Propofol or Versed/fentanyl with vec as a paralytic.

 

[Carlos Danger]

My service does a fair amount of vented community hospital to level 1 IFT and I've not seen Ketamine used in the post RSI sedation package. It's usually Propofol or Versed/fentanyl with vec as a paralytic.

Yeah, I've never even seen it, I don't think. You certainly could use it I suppose, but I think the "ketamine for everything" craze has gotten a little out of hand. It is not necessarily the best agent for every situation.

 

[Tigger]

We are able to use it at 2mg/kg boluses for sedation. Anecdotally it seems to work alright and may be preferable in patients that are prone to hypotension as the alternative is Versed/fent. Propofol is a CCT only thing here, even on IFTs.

 

[TXmed]

http://www.smacc.net.au/2015/12/ketamine-how-to-use-it-fearlessly-for-all-i

it has become very popular in the state of texas. I use it very frequently in the HEMS service i currently work for and used it regularly during IFT on the ground service i used to work for. It goes great when used with propofol. i will usually give them a dose prior to moving and may or may not have to dose them depending on how rough the unloading process is. I have also found it helps alot with vent synchrony. every study i read or podcast i listen talks great about ketamine. while yes those side effects remi named are true they are not as profound or as common as what was once thought and i believe should not stop you from giving ketamine. but that is just an opinion of mine. I fully encourage talking to your medical director to see how he wants his paramedics to use the medication.

 

[TXmed]

http://www.bijc.org/article-reviews/analgosedation-with-ketamine-in-the-icu-what-is-the-evidence

 

[18G]

There's no question that an infusion will result in more steady serum levels of the drug. With any sedative or analgesic, you'll likely find yourself giving less total dose of the drug over several hours with an infusion vs. bolus dosing. There isn't a "trick" to it, you just give a bolus and start the infusion, then adjust the infusion up or down as needed. But if you want the patient completely still, neuromuscular blockers are the best way to do it.

50 mcg of fentanyl is probably far too little to have any appreciable sedative effect in transport.

Actually, ketamine has plenty of potentially adverse effects, the risks of which increase with higher doses or faster rates of administration. Respiratory depression, loss of airway reflexes, hypersalivation, laryngospasm, seizures in susceptible individuals, and both systemic and intracranial hypertension, to name a few. It is true that the estimated LD50 requires much more ketamine (240 mg/kg) than you probably even have have available, but that doesn't mean that you can't give someone too much of it.

In a perfect world yes, give the bolus and start the drip. But we are at the mercy of the ED physician and RNs who like to run interference sometimes because they don't understand why we're asking for the orders. In my case, the RN tried to get out of giving me a full vial of ketamine for transport because she obviously never heard of EMTALA and wasn't aware that ketamine is to be dosed q5-15mins. The ED was gonna send this patient 35mins away with only a single, pre-drawn syringe of 80mg of ketamine. Sometimes you need to pick and choose your battles, and in this case we wasted enough time already and I just wanted to get the patient to the CCU. I felt comfortable with bolus dosing the ketamine for 35mins and had fentanyl and Versed available.

 

[Carlos Danger]

In a perfect world yes, give the bolus and start the drip. But we are at the mercy of the ED physician and RNs who like to run interference sometimes because they don't understand why we're asking for the orders. In my case, the RN tried to get out of giving me a full vial of ketamine for transport because she obviously never heard of EMTALA and wasn't aware that ketamine is to be dosed q5-15mins. The ED was gonna send this patient 35mins away with only a single, pre-drawn syringe of 80mg of ketamine. Sometimes you need to pick and choose your battles, and in this case we wasted enough time already and I just wanted to get the patient to the CCU. I felt comfortable with bolus dosing the ketamine for 35mins and had fentanyl and Versed available.

I understand those situations well.

Not being there of course, I'll take a leap and guess that the nurse was not hesitant to give you 500mg of ketamine because "she doesn't understand EMTALA", rather she probably didn't think you'd need that much for a 35 minute trip and was concerned about hospital policies and federal laws that govern the handing over of an entire vial of a scheduled substance with no mechanism for documenting administration and waste. At any rate, these things are as much the fault of your EMS agency and medical director as they are the fault of the sending facilities.

Back to your original question - I don't think there is any practical way to make bolus dosing as smooth as an infusion. At least not unless you have a lot of experience with the drug. Frequent small boluses should do it, but of course that is labor intensive.

Given my experience with ketamine, I personally would have given a large bolus upon leaving the sending facility, and then not given any more until the patient looked like the needed it, at which point I would simply repeat the original dose. Or actually more likely, I would have just skipped the ketamine altogether.

Ketamine is like a Gerber or Leatherman multi-tool. It's great to have a single tool that works OK for pretty much anything. But if I have a toolbox full of dedicated tools at my fingertips, a multi-tool will only occasionally be the first thing I reach for.

 

[Akulahawk]

If you're out of ketamine (or you think you may run out before the trip's done), and you have fentanyl and midazolam, ativan, or diazepam, you could use those agents to keep the patient sedated... just get an order for it (or have it on standing order) so that you can switch over to your "backup" meds in case you run out of the ketamine.

My ED docs seem to like etomidate for RSI sedation and then propofol with occasional fentanyl boluses if necessary to keep the patient sedated.

 

[Nova1300]

It is one of my favorite sedative medications and I use it not infrequently. I tend to give a small bolus dose (10-30 mg) when starting the infusion, and follow that with 10-30 mg/hr regardless of the patient's weight. I rarely find those doses to be dissociative or dysphoric, but instead leave a comfortable, calm patient with just a hint of nystagmus but fully willing and able to follow commands. I'm not sure I can say the same for 1-2 mg/kg doses, which would result in much larger doses than I use. Im also not sure that repeat bolus dosing is the best strategy for a dissociative drug. I would get squirrely too if I was coming back from Mars every 15 minutes only to be skyrocketed back to space. I also rarely use it as monotherapy, but instead almost always combined with some other adjunct, be it a benzo, fentanyl or precedex. Having a secondary sedative or analgesic is probably key in being able to use relatively low infusion doses.

Just to add to what Remi mentioned, Ketamine is not without its potential hazards. Ketamine is a myocardial depressant. Generally its negative effects on cardiac output are offset by causing catecholamine release via stimulation of the autonomic nervous system. However, in patients with with depleted catecholamine stores such as end-stage heart failure or severe sepsis, there may not be enough catecholamine available to offset the decreased cardiac output, resulting in hypotension and potentially shock after an induction dose of ketamine.

 

[18G]

I understand those situations well.

Not being there of course, I'll take a leap and guess that the nurse was not hesitant to give you 500mg of ketamine because "she doesn't understand EMTALA", rather she probably didn't think you'd need that much for a 35 minute trip and was concerned about hospital policies and federal laws that govern the handing over of an entire vial of a scheduled substance with no mechanism for documenting administration and waste. At any rate, these things are as much the fault of your EMS agency and medical director as they are the fault of the sending facilities.

The kicker here is that I work for the hospital. The RN and myself are employees of the same health system. EMTALA requires that the sending hospital supply all medications that the patient will need in transport no matter if controlled substances or not. Documentation is as simple as notating the transfer of medication in the EPIC system. Once the medication is turned over to the paramedic, the RN is no longer responsible for it. Documentation of administration comes in the form of a legal document called the patient care report. Waste is documented on an agency waste form that is always witnessed by an RN at the receiving hospital. Again, we are all part of the same health system so you wouldn't think this issue would exist. Nurses don't understand the obligation under EMTALA, but that is a discussion for another thread. I agree that the EMS agency can do more, but they have tried to get this issue resolved as much as possible. When you have a turn over of ED staff it becomes an ongoing problem.

Thanks everyone for the input so far!

 

[medicsb]

For a 35 minute transport, I'd go with versed and fentanyl. Could also do versed and morphine (I've only done this when working in the Burn ICU as that was a preference of the attending surgeon). Just because a sending facility is using a particular regimen doesn't mean you have to go along with it.

 

[CANMAN]

If we use Ketamine for an RSI we will start a drip for sedation post RSI bolus in our protocols. We will also continue it coupled with analgesics if it's running already in drip form upon our arrival somewhere. Otherwise our sedation cocktails are usually some variation of fentanyl, versed, or propofol.

 

[Doczilla]

I've used it in serial boluses, and maintenence infusions, in conjunction with versed.

I've used it extensively for induction/maintenence, PSA for fracture reductions, chest tubes, and minor surgical procedures, difficult dental extractions, and low-dose for tourniquet pain that was not ammendable to local anesthesia.

Infusions are much more desirable in my opinion; though with short transport times, they may not be neccesary. EMS systems are still in their infancy in utilizing this versatile drug, and they seem to be allergic to hanging maintenence infusions. They just want you to shoot in the dark and keep pushing it.

That's fine, I guess, since hypersalivation isn't as much of an issue if they're intubated, but it should still be avoided if possible. It should always be used in conjunction with a benzo to attenuate emergence phenomenon in case they break back into reality. Ketamine is a theshold medication. They can dip in and out of the k hole as serum levels fluctuate.

Hospitals aren't keen on it so far also, because the ER doc that's receiving your patient sometimes forgets that you don't have a pharmacist at your disposal with a fridge full of sedatives and high quality I.V pumps.

 

[Doczilla]

Yeah, I've never even seen it, I don't think. You certainly could use it I suppose, but I think the "ketamine for everything" craze has gotten a little out of hand. It is not necessarily the best agent for every situation.

I agree wholeheartedly. I came back singing the praises of ketamine's versatility, only to he greeted with "that's a cat tranquilizer". Now it's the goddamned flavor of the month. There were instances where I would have much favored propofol, but didn't feel like waiting 20 mins for someone to wake up because it had to be given the old fashioned way due to lack of I.V pumps.

 

[Underoath87]

Since we've got the big guns are here and we're talking about Ketamine: why is ketamine dosing based on ideal body weight (height) rather than actual weight? It seems weird to me that a morbidly obese pt receive the same dose as their slender counterpart.

Based on the few experiences I've had with it, ketamine seemed more potent in those with a lower BMI...

 

[Nova1300]

Since we've got the big guns are here and we're talking about Ketamine: why is ketamine dosing based on ideal body weight (height) rather than actual weight? It seems weird to me that a morbidly obese pt receive the same dose as their slender counterpart.

Based on the few experiences I've had with it, ketamine seemed more potent in those with a lower BMI...

Anesthetic drugs are distributed immediately upon injection to the organs that receive the most cardiac output. That means the liver, kidneys, brain.

That initial distribution, which quickly deliver the drug to its site of action (the brain), accounts for the rapid onset of these drugs (several seconds after injection).

From there, these drugs will redistribute out of the high cardiac output organs and move into the fat tissue. They hang out in the fat for a while, but clearly will have no anesthetic effect there.

And, no matter how fat you are, your kidneys, liver, and brain don't grow with your waistline. Same number of receptors to be agonized by the initial dose of propofol.

So we inject a dose of propofol, the drug goes immediately the the 600 lb patient's brain, liver and kidneys (which have the same number of receptors as a 150 lb patient). The propofol exerts its effect on the receptors, patient goes to sleep.

A few minutes later, propofol redistributes to 600 lb patient's fat tissue to hang out for a while, but patient wakes up because propofol is leaving that brain, liver, kidney compartment.

So, putting a patient to sleep with most anesthetic agents should be done based on ideal body weight.