It’s time for another post on everyone’s favourite drug: ketamine! Hooray!
Ok, so this is not entirely about ketamine, but ketamine does come into it. AV paramedics have recently received training to administer IM ketamine to agitated patients as part of a greater focus on paramedic safety when managing these situations(MICA paramedics have had ketamine for a while, it is now used by all paramedics)
Speaking with crews since the roll-out, there seems to be some confusion around some aspects of managing these patients, so I thought I would attempt to
exacerbate alleviate that. This post is pretty specific to Victoria I’m afraid, so everyone else might want to find a more useful blog to peruse (i.e. any other blog).
The two main issues that seem to be causing confusion, are 1) when do we give ketamine, and 2) why do we need MICA?
So, when do we give ketamine? The CPG is pretty clear in this regard, having separate pathways for agitated patients, and severely agitated/violent/dangerous patient. However, it seems that the message coming out of training is that any patient who needs managed, especially if they need mechanical restraint, needs ketamine. This is not the case.
The CPG we have has a graduated approach to the patient with agitation, similar to the approach outlined here:
Obviously the pharmacology we have is different: midazolam or ketamine, however the intent behind our CPG is the same, as can be seen in the notes in this guideline:
- The Mild/Moderate Agitation pathway is intended for patients who do not present a high risk of extreme violence or for whom the risk is expected to be controlled with Midazolam alone, e.g. a combative dementia patient or a hyperthermic psychostimulant patient presenting with agitation/restlessness rather than violence.
- The Extreme Agitation pathway is intended to provide protection for patients and staff in circumstances where there is a high risk of extreme violence and the priority is to sedate the patient quickly. It should be applied judiciously and exercising clinical judgement.
The vast majority of agitated patients we see fall into the Mild/Moderate Agitation guideline and will be amenable to de-escalation strategies, or failing that, de-escalation strategies and a little IM midazolam.
The Extreme Agitation guideline is for when we need rapid control of a patient who is extremely agitated, violent, and a risk to themselves or others. Often (but not always) these will be patients who are affected by stimulants. “Ice” (methamphetamine) is what we all worry about, but honestly, I find “bath salts” (synthetic cathinones) just as bad, if not worse, and synthetic marijuana is also a concern.
However we need to remember that there are many things that cause agitation, and we should never jump to the conclusion that stimulant use is all that is happening when we come across the extremely agitated patient. It is entirely possible that these patients may have an organic disorder, either exacerbated by stimulants, or in isolation without drug use.
Which brings us to the next point of confusion: why do we have to call for MICA for these patients when we have ketamine now?
The simple answer is: the extremely agitated patient is extremely sick.
The patients who need rapid takedown and control with ketamine – the highly agitated, violent, dangerous, excited delirium patient – are people who are at risk of rapid deterioration and death.
They are typically hypermetabolic, hyperthermic, and acidotic as a result of the drugs (which affect dopamine and serotonin transport), and physical activity. They are at risk of cerebral oedema, rhabdomyolysis, renal failure, cardiomyopathy, cardiac channelopathies, cardiac ischaemia, and electrolyte abnormalities, any of which may cause death.
These are not irritable people who punched a wall, mouthed off at the cops, or were otherwise angry, uncooperative, or generally have shit on the liver. They are sick patients with severely deranged physiology, and they need managed aggressively and appropriately. This may include going as far as intubation, paralysis, and ventilation in some cases. So they are definitely patients you want MICA backup for.
Unfortunately we all (quite naturally) focus on the behaviours the patient displays, often to their detriment. These behaviours are a symptom, not the disease. We sometimes can have an unfortunate tendency to think of these patients as bad, not sick. This is compounded by the threat they may pose to our safety, which we cannot help but take a little personally! Then, when the ketamine is in, and the drama is over, we relax. Unfortunately, when we let our guard down is exactly when disaster strikes…
So, most patients who are agitated don’t need much more than some good de-escalation. Some will need some chemical/physical restraint. But the truly ketamine deficient patient is relatively rare, and jabbing everyone with ketamine will do nobody any favours. By all means, err on the side of caution, but don’t be indiscriminate with the special-K. Ketamine is a good drug, but we shouldn’t fall prey to the idea that it is completely benign. We know that we need to take great care when midazolam has been administered, but I’m concerned that the message of “ketamine is safe” will lead us into all sorts of trouble.
In my next post I will continue the discussion with some of the practicalities of managing the patient with extreme agitation: until then, stay safe out there.
Ambulance Victoria. (2016). Clinical practice guidelines for Ambulance and MICA paramedics. Doncaster, Vic.: Ambulance Victoria.
Takeuchi, A., Ahern, T. L., & Henderson, S. O. (2011). Excited delirium. Western Journal of Emergency Medicine, 12(1).