By Mark Kroll, PhD, FACC, FAIMBE, Jeffrey Ho, MD, & Gary Vilke, MD, FACEP, FAAEM, P1 Contributors
Excited delirium syndrome (ExDS) continues to be a major problem for law enforcement that is associated with a high percentage of arrest-related deaths. Fortunately, several quality studies of ExDS have been recently published so we now know a lot more about how to recognize and treat it. Here is a summary of eight key findings:
1. The basics have not changed.
Much of the initial writing on ExDS is still accurate and recommendations from the American College of Emergency Physicians’ White Paper Report on Excited Delirium Syndrome should be followed.  Decreased stimulation and training for de-escalation is a reasonable thing as well, but realize that de-escalation training does not have a high likelihood of changing outcomes significantly.  ExDS subjects often require physical restraint combined with emergent sedation. Once the decision to do this has been made, action needs to be swift and efficient, and performed with all responders present when feasible.
2. “Spice” is now a recognized substance of abuse associated with ExDS.
In the past, most cases of ExDS were linked to chronic abuse of methamphetamine, cocaine, or PCP, or poorly controlled mental illness such as schizophrenia or bipolar disease. Today, synthetic marijuana analogs or “cathinones” (aka “spice,” “flakka,” or “bath salts” ), are also known to be associated with ExDS. 
3. EMS and sedation.
It is believed that once an officer has become concerned about a person exhibiting ExDS, EMS should be asked to respond to evaluate the patient. Best practice suggests that sedation should be considered for safe management of ExDS. Several sedatives are used for this medical emergency including ketamine, which is gaining in popularity. A 2018 review and meta-analysis paper suggests it may be a nearly ideal sedative as it can be administered intramuscularly, readily crosses the blood-brain barrier, and has a typical onset of action of under 5 minutes and a duration of 30 minutes.  Ketamine would seem to be optimal based on today’s thinking that what kills these people is profound acidosis and excess circulating adrenaline. Stopping the agitation and exertion quickly is likely key. The caveat is that while ketamine may offer the best chance for survival, it is not a guarantee of survival. ExDS is a medical emergency and even if the optimal care is provided, the risk of a fatal outcome is present.
4. The role of tactile hyperthermia (elevated body temperature or hot to the touch)
Tactile hyperthermia appears to correlate closely with the more serious and potentially fatal ExDS cases. A 2018 paper by Ross and Hazlett reported on a study of 1,085 forceful arrests.  A majority (635 subjects) were felt to be acting in an abnormal or intoxicated manner. Tactile hyperthermia was only seen in 11 of the 635, so about 2%. A 2016 study by Baldwin et al found this in 8 of his 441 cases or 2% of those showing some signs of ExDS.  Thus, tactile hyperthermia may be less common that we used to think. However, tactile hyperthermia was the hallmark sign of the most severe ExDS cases and could thus be a harbinger of lethality. 
5. More dangerous than drunks.
Another very interesting 2018 paper by Baldwin et al looked at officer risk with ExDS cases.  This involved 2,836 forceful arrests of subjects judged to be emotionally disturbed by officers. This was 31.5% of the total forceful arrests of 9006 in this study. Of the total forceful arrests, 906 (10% of the total, but 32% of the emotionally disturbed) displayed at least 3 signs of ExDS. They found an interesting correlation between the ExDS severity and the number of officers called to the scene – the more ExDS features, the more officers required for control.
In the past, some have suggested that a violent drunk might be confused with an ExDS case. Not so much. Baldwin found a strong inverse correlation between alcohol intoxication and the number of ExDS features. Of the 3,704 “merely drunk” (alcohol only) cases, 97% had less than 3 ExDS signs. Only 3% had between 3 and 5 ExDS signs; only 7 (0.2%!) had 6 or more ExDS signs. ExDS subjects were far more violent than the drunks. Subjects with probable ExDS (at least 6 features) were about 4 times as likely to threaten great bodily harm than those with under 3 features. With probable ExDS, 89% of the time there was a struggle that went to ground.
6. Media myths persist.
This includes the myth that ExDS deaths require law enforcement officer restraint. The truth is that solo at-home deaths have been documented for over 20 years with subjects often surrounded by wet towels and even empty ice trays to deal with the hyperthermia.  A typical example of a non-police-related fatal outdoor case report involved a man found nonresponsive and nude near a Philadelphia park with a rectal temperature of 107° F. 
Another popular myth is that the American Medical Association (AMA) does not recognize ExDS. That has been false since 2009 when the annual meeting of the AMA passed a resolution that included the following: “Excited delirium is a widely accepted entity in forensic pathology and is cited by medical examiners to explain the sudden in-custody deaths of individuals who are combative and in a highly agitated state. Excited delirium is broadly defined as a state of agitation, excitability, paranoia, aggression, and apparent immunity to pain, often associated with stimulant use and certain psychiatric disorders.” 
7. Asking for early EMS staging remains a good management strategy.
EMS should be provided with immediate access to the individual to start assessment and treatment when safe to do so. ExDS is a medical emergency and it is not necessarily up to the officer to make the decision whether or not the subject should or should not be seen by EMS. Having them evaluated by EMS is never going to be the wrong answer because other medical problems can mimic ExDS such as low blood sugar, seizures, or intoxication. Having the benefit of a clinical perspective with agitated subjects works in an officer’s favor by covering potential issues of which the officer may not have considered.
8. Glass under the microscope.
It has been long taught that attraction to glass, bright lights, or shiny objects is a sign associated with ExDS. However, in the Ross study, of the subjects with 3 or more ExDS signs, this was only reported in 4 of the 635 so under 1%. The 2016 Baldwin study included glass destruction (and not just attraction) and they found this in 64 or 15% of the 441 cases with 3 or more signs. An earlier (2012) Canadian study found glass attraction or destruction in only 17% of subjects with 3 or more ExDS signs. 
There is some correlation between glass and ExDS, but this particular sign does not appear to compete with the more common signs mentioned above in the AMA list. This does not mean that it is okay for an officer to shine all their lights on the subject and assume that such stimuli are no longer a problem. The new questions about glass are based on self-reporting of officers and there is a high likelihood that many such interactions were missed or simply not entered. It is probably too soon to throw glass out of the window.
We are learning some new things about excited delirium syndrome that we did not know a few years ago. Hopefully, this information will be of some benefit to the law enforcement officers who have to handle this extremely challenging condition when responding to calls.
1. Vilke GM, DeBard ML, Chan TC, Ho JD, Dawes DM, Hall C, Curtis MD, Costello MW, Mash DC, Coffman SR, McMullen MJ, Metzger JC, Roberts JR, Sztajnkrcer MD, Henderson SO, Adler J, Czarnecki F, Heck J, Bozeman WP. Excited Delirium Syndrome (ExDS): Defining based on a review of the literature. J Emerg Med. 2012;43:897-905.
2. Taheri SA. Do crisis intervention teams reduce arrests and improve officer safety? A systematic review and meta-analysis. Criminal Justice Policy Review. 2016;27:76-96.
3. Castellanos D, Menendez B, Logan B, Mohr A, Ayer D. Flakka. Intoxication: What have We Learned. 2018.
4. Mankowitz SL, Regenberg P, Kaldan J, Cole JB. Ketamine for Rapid Sedation of Agitated Patients in the Prehospital and Emergency Department Settings: A Systematic Review and Proportional Meta-Analysis. J Emerg Med. 2018;55:670-681.
5. Ross D, Hazlett M. Assessing the symptoms associated with excited delirium syndrome and the use of conducted energy weapons. Forensic Research & Criminology International Journal. 2018;6:187-196.
6. Baldwin S, Hall C, Bennell C, Blaskovits B, Lawrence C. Distinguishing features of Excited Delirium Syndrome in non-fatal use of force encounters. J Forensic Leg Med. 2016;41:21-7.
7. Baldwin S, Hall C, Blaskovits B, Bennell C, Lawrence C, Semple T. Excited delirium syndrome (ExDS): Situational factors and risks to officer safety in non-fatal use of force encounters. Int J Law Psychiatry. 2018;60:26-34.
8. Wetli CV, Mash D, Karch SB. Cocaine-associated agitated delirium and the neuroleptic malignant syndrome. Am J Emerg Med. 1996;14:425-8.
9. Plush T, Shakespeare W, Jacobs D, Ladi L, Sethi S, Gasperino J. Cocaine-Induced Agitated Delirium: A Case Report and Review. J Intensive Care Med. 2013.
10. American Medical Association. Use of TASERS by Law Enforcement Agencies (Resolution 401, A-08). Resolutions of the 2009 AMA National Convention. 2009.
11. Hall CA, Kader AS, Danielle McHale AM, Stewart L, Fick GH, Vilke GM. Frequency of signs of excited delirium syndrome in subjects undergoing police use of force: Descriptive evaluation of a prospective, consecutive cohort. J Forensic Leg Med. 2013;20:102-7.
About the authors Mark Kroll, PhD, FACC, FAIMBE, is a biomedical scientist with a primary specialty in bioelectricity. He is an adjunct full professor of biomedical engineering at the University of Minnesota and the California Polytechnic University. He was awarded “fellow” recognition by the American College of Cardiology and the Heart Rhythm Society, and awarded fellow status by the Engineering in Medicine and Biology Society and the American Institute for Medicine and Biology in Engineering. He is the author of over 200 abstracts, papers, and book chapters and co-editor of 4 books including “TASER® Conducted Electrical Weapons: Physiology, Pathology and Law” and “Atlas of Conducted Electrical Weapon Wounds and Forensic Analysis.” Mark frequently serves as an expert witness in use-of-force litigation and also sits on the Axon scientific and corporate board.
Jeffrey Ho, MD, is a board-certified emergency medicine physician who practices clinically at Hennepin Healthcare Medical Center, an urban Level 1 trauma center in Minneapolis. He was awarded a Bush Foundation Medical Fellowship in Law Enforcement in 2003, which allowed him to complete his peace officer standards training. He is a licensed deputy sheriff in the state of Minnesota and currently serves in uniform patrol with the Meeker County (Minn.) Sheriff’s Office. Dr. Ho has served as a medical director/operator of an urban SWAT team. He regularly consults with law enforcement agencies and government on issues of sudden custodial death and conducted electrical weapons. He holds the academic rank of professor of Emergency Medicine at the University of Minnesota and is the medical director to Axon Enterprise (formerly TASER International).
Gary M. Vilke, MD, FACEP, FAAEM, is a professor in the Department of Emergency Medicine at the University of California, San Diego (UCSD) since 1996 and is the former medical director for the County of San Diego Emergency Medical Services. Dr. Vilke served as the director for custody services at UCSD for over 15 years, working at the San Diego County Sheriff’s jails weekly and caring for thousands of inmates. He has published over 220 original articles and 70 book chapters, including over 60 articles on topics including positional asphyxia, weight force on the back, OC spray, neck holds, restraint chairs, excited delirium syndrome and the TASER. He has lectured internationally on these topics and co-authored with Darell Ross the book, Guidelines for Investigating Officer-Involved Shootings, Arrest-Related Deaths and Deaths in Custody.