This week’s protocol was requested from one of our residents following the recent surge in coverage of Elijah McClain’s 2019 death and the associated controversy around the use of ketamine as a sedation agent. Protocol 530, Excited Delirium, discusses more than just ketamine administration, and I’d like to use this space to discuss the protocol overall without making this a ketamine-specific email. That being said, this is the only one out of all the NYC REMAC protocols to even mention ketamine, so I’ll touch on it a bit here, and hopefully we can use this to kick off a conversation about our own perspectives and experiences with administering ketamine, whether in-hospital or out-of-hospital. First thing to note about this protocol is that it is not a protocol for anxiety, nor is it for simple agitation. This is not supposed to be the go-to for the little granny with dementia who’s shouting expletives at passerby. Excited delirium is intended to encapsulate the belligerent, aggressive, potentially violent patient, for a couple of key reasons. For one, same as in the ED, you want to be able to quickly intervene on patients that pose an acute threat to themselves and/or first responders. Further than that, depending on etiology, you want to be able to quickly control the patient that is truly hypermetabolic, preferably without prolonged physical restraint, in order to prevent worsening hyperthermia or acidosis, either of which can be rapidly lethal if unmitigated. Protocol 530 starts with reference to BLS procedures, which put a large emphasis on rapidly ensuring scene safety, both by attempting verbal de-escalation but also having a low threshold for requesting assistance from law enforcement. For the ALS component, note that the default Standing Order for continued patient resistance is 10mg of IM midazolam. Not “up to,” not a weight-based calculation, just a flat 10mg dose. A quick note about that. The reasoning is, broadly, to quickly control the potential threat to first responders with the lowest potential for needlestick injuries in the process (whether from placing an IV or from attempting multiple IM injections). Yes, there is controversy about this dosing strategy. Ideally, if ALS has a 30kg geriatric in true excited delirium requiring medication, the paramedic will be cognizant enough to call OLMC for a Discretionary Order for a lower dose. What I can tell you is that during my time with FDNY, we looked at data surrounding administering 10mg midazolam IM for excited delirium in NYC and found it to be relatively safe, with the most common complication being hypotension that was responsive to IV fluids (the next SO in the protocol). If adequate sedation is achieved with the SO midazolam, great, EMS will package the patient and transport. If that dose somehow isn’t enough, expect an OLMC call for one of the MCO’s listed in the attached pdf. The request may be for a repeat dose of IM midazolam (this time “up to 10mg”) or IM lorazepam if the crew carries it. Another option is IN benzos (although these tend to not be preferred due to patients spitting them back at providers), or IV/IO benzos if the initial SO midazolam briefly calmed the patient enough for the crew to obtain vascular access. Finally, there is the option for ketamine, either IN (again, often not preferred) or IM. Now, a few things about ketamine. Recognize that many EMS services in NYC do not yet carry ketamine (although obviously our own Maimo medics do). This has been another example of how practice in the prehospital setting has developed somewhat behind that in the ED or the rest of the hospital. Similarly to how ketamine has surged in popularity in the ED over the last several years, so too is it now getting lots of attention in EMS systems. However, the “ketamine can do no wrong” mentality started to stall a few years ago after some studies began to show some adverse effects from its use. One of the most impactful papers was the 2016 study from Hennepin County, MN, comparing prehospital ketamine to haloperidol, which showed superior sedation but a worse side effect profile, specifically a significantly increased rate of subsequent intubation. Why? While this may be partially related to ketamine-induced laryngospasm, there is an argument that a large part of this is explained by inexperience with ketamine and unfamiliarity with how to manage a dissociated patient. There is also a question of correlation between ketamine dosing and adverse effects. The Hennepin study, along with many other EMS systems, utilizes a 5mg/kg dosing strategy for IM ketamine; for context, Elijah McClain appears to have been given a good deal more. Our own protocol here in NYC calls for 2-4mg/kg IM. Of note, a more recent study by the same Hennepin group comparing prehospital ketamine to midazolam was suspended after public backlash over informed consent with regards to ketamine administration. Finally, note that this protocol explicitly states in its title that it is for adults only. For NYC EMS, although you are considered a minor until the age of 18, you are only a pediatric patient until the age of 15. What this means is that you very well may encounter 16-year-olds who have received midazolam as Standing Order, and you may receive OLMC calls for large, violent 14-year-olds requesting a Discretionary Order for sedation. In the latter case, use your judgment, but remember to consider patient and provider safety, and if you do authorize the use of sedation, be sure to get an accurate weight for dosing. Very interested in hearing all of your takes on prehospital management of excited delirium, in-hospital and out-of-hospital (CLINICAL) ketamine use, and anything in between! Feel free to reply to this email chain, and in the meantime, keep checking out www.nycremsco.org and the protocols binder!
–– David Eng, MD Assistant Medical Director, Emergency Medical Services Attending Physician, Department of Emergency Medicine Maimonides Medical Center
