Alcohol induced delirium and Ketamine

NPO

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I have been hearing multiple reports from field providers that they have been giving large IM doses of ketamine (within protocol) and that every time the patient 'required' intubation upon arrival at the ED due to respiratory compromise. In every case alcohol has been a compounding factor.

Personally, I believe it hasn't been 'required' but was probably an over zealous knee-jerk reaction by the ED physicians. We are serviced by a small community hospital who's ER staff tend to be lacking in the "advanced" category. Ketamine, for example, is not something they use often if ever in the ED.

However, I have seen several articles where patients did truly suffer adverse consequences from ketamine and alcohol induced delirium, and I'm open to the possibility that that's what is happening.

Is there truly a mechanism for alcohol and Ketamine to potentiate so strongly as to cause respiratory depression? Is it related to rate of administration?

I've never had an issue, and like I said, I don't truly believe these patients "need" airway support, I think they're just seeing a KO'd drunk patient and over reacting.
 

justin1232

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Going off what I recently listened to on a emcrit podcast, there had been veryyyyy few cases of ketamine cashing respiratory depression, and In the cases it has, it wasn't ever truly identified of being due to ketamine since the patient was also under other drugs/disease states/ etc. the only literature on the matter is if ketamine is pushed quickly it can cause 15-30 seconds of apnea. but by going the IM route I'm pretty sure that get avoided.
I feel it is more of the matter of them seeing a KOd patient and not wanting to have to watch over them to make sure there airway stays patent.
 

RocketMedic

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It’s happened to me, twice, both in the context of profound ETOH intoxication.

Case 1: Male, young 20s, mass maybe 70kg. LOTS of liquor quickly, plus some synthetic marijuana, plus “maybe” some cocaine. Initial presentation was psychotic, nonviolent but threatening to jump off of the roof of a three-story apartment and “fly to fight the devils”/agitated/erratic, became combative after PD/FD tackled him and lowered him to ground. I knew about the synthetic marijuana and some of the alcohol, cut our standard ED dose of 4mg/kg (a heavy one) down to 2mg/kg and gave 150mg IM. Patient calmed down within 2 minutes...then started to become depressed, progressing rapidly to apnea. Luckily, we had prepared for that, so we simply ventilated him, suctioned when he vomited and intubated him. BAC was .45 an hour later at the hospital, and we learned he’d also consumed a half-gallon or so of schnapps in addition to everything else he’d drank and smoked. I don’t think the ketamine kept him down, but I do believe that it was the potentiating agent in his respiratory failure and it really hammered home the point that sedation needs to be prepared for with an eye towards immediate airway and ventilators support.

Case 2 was somewhat similar- 35 y/o M, approximately 140kg, severe depression + suicidal thoughts + significant ETOH intoxication and lots of opiates and probably a lot of Xanax on board. Dude’s girlfriend came over to check on him because he’d left some disturbing messages, caught him tasting his AR and talked him down, called us and SO. By the time we arrived, SO had him in custody, but had not yet restrained him and he was getting angry. He was a very large, strong man with combatives experience (former Marine) and was winning the fight against both (armed) deputies, so I dropped 500mg IM and the rassle stopped pretty quickly. Just like the last one though, that calm period was followed by about twenty minutes of spontaneous hypoventilation, which we were able to BVM our way through. No Narcan, because I didn’t want to take away whatever sedative affects he was enjoying from that, and the BVM did a splendid job of ventilation without need for further adjuncts. After about twenty minutes, respiration’s rapidly returned to normal and adequate, patient remained calm and we transported without incident. Unlike the first one though, he didn’t vomit, so I didn’t see it as vital to intubate him. Didn’t get a BAC, but he reeked of ETOH and had been drinking non-stop for at least a day per GF. There was also Rx norco and Xanax involved in the party, but dose/time are unknown.

Overall, I think that alcohol is a strong danger sign for ketamine in prudent practice. It’s relatively safe, yes, but if you sedate with ketamine (or anything else), you need to be prepared for rapid respiratory collapse and potential airway management. I think this is a combination of the fact that we’re rapidly loading enough meds on to physically affect the cognitive process and that we’re doing it in the presence of other substances that have their own affects on the body, particularly alcohol. At a minimum, I recommend that ketamine sedation be performed in the presence of a BVM and suction unit, and that whomever performs the sedation be aware of, prepared for and willing to manage the airway/ventilation to the best of their ability within their scope of practice.
 

Remi

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Large doses of ketamine can definitely cause direct respiratory depression, and like any other drug that can, those effects are absolutely more pronounced when combined with other respiratory depressants.

Ketamine is considered safer than other anesthetics in this way because 1) it generally takes a much higher dose than other sedatives to achieve significant respiratory depression, 2) the respiratory depression is generally more transient, and 3) probably the biggest advantage ketamine has in terms of breathing is that it enhances or at least maintains airway tone. This means that you are less likely to get the passive upper airway obstruction that often results from sedation with other drugs, and which is probably a more common cause of severe hypoventilation following opioid administration than direct depression of respiratory effort.
 
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