Prehospital Ketamine is a Safe and Effective Treatment for Excited Delirium in a Community Hospital Based EMS System

Abstract

Excited delirium syndrome (ExDS) is defined by marked agitation and confusion with sympathomimetic surge and incessant physical struggle, despite futility, which may lead to profound pathophysiologic changes and sudden death. Severe metabolic derangements, including lactic acidosis, rhabdomyolysis, and hyperthermia, occur. The pathophysiology of excited delirium is a subject of ongoing basic science and clinical research. Positive associations with ExDS include male gender, mental health disorders, and substance abuse (especially sympathomimetics). Excited delirium syndrome patients often exhibit violent, psychotic behavior and have "superhuman" strength which can result in the patient fighting with police and first responders. Continued struggle can cause a patient with ExDS to experience elevated temperature (T) and acidosis which causes enzymes to fail, leading to sudden death from cardiovascular collapse and multi-system organ failure. Therefore, effective early sedation is optimal to stop this fulminant process. Treatment of ExDS must be focused on rapidly, safely, and effectively sedating the patient and providing intensive, supportive care. Benzodiazepines, like midazolam, may not be ideal to sedate ExDS patients since their onset takes several minutes, and their side effects include loss of airway control and respiratory depression. Injectable antipsychotic medications have a relatively slow onset and may cause prolongation of the QTc interval. Ketamine is the ideal medication to sedate patients with ExDS. Ketamine has a rapid, predictable onset within three to four minutes when given by intramuscular (IM) injection. It does not adversely affect airway control, breathing, heart rate, or blood pressure (BP). In this retrospective case series, prehospital scenarios in which ExDS patients received ketamine by paramedics for sedation, and their subsequent treatment in the emergency department (ED) and hospital, are described. It is demonstrated that ketamine administered by paramedics in the prehospital setting of a community hospital based Emergency Medical Services (EMS) system is a safe and effective treatment for ExDS. Scaggs TR , Glass DM , Hutchcraft MG , Weir WB . Prehospital ketamine is a safe and effective treatment for excited delirium in a community hospital based EMS system. Prehosp Disaster Med. 2016;31(5):563-569.

Keywords: BP blood pressure; CK creatinine kinase; CO carbon dioxide; ED emergency department; EMS Emergency Medical Services; ETOH ethanol; Emergency Medical Services; ExDS excited delirium syndrome; IDPH Illinois Department of Public Health; IM intramuscular; IV intravenous; P pulse; R respiration; SpO oxygen saturation; T temperature; WBC white blood cells; delirium; ketamine; therapeutics.