Psychiatric Outcomes of Patients With Severe Agitation Following Administration of Prehospital Ketamine

Abstract

Background: Ketamine is an emerging drug used in the management of undifferentiated, severe agitation in the prehospital setting. However, prior work has indicated that ketamine may exacerbate psychotic symptoms in patients with schizophrenia. The objective of this study was to describe psychiatric outcomes in patients who receive prehospital ketamine for severe agitation.Methods: This is a retrospective cohort study, conducted at two tertiary academic medical centers, utilizing chart review of patients requiring prehospital sedation for severe agitation from January 1, 2014, to June 30, 2016. Patients received either intramuscular (IM) versus intravenous (IV) ketamine or IM versus IV benzodiazepine. The primary outcome was psychiatric inpatient admission with secondary outcomes including ED psychiatric evaluation and nonpsychiatric inpatient admission. Generalized estimating equations and Fisher's exact tests were used to compare cohorts.Results: During the study period, 141 patient encounters met inclusion with 59 (42%) receiving prehospital ketamine. There were no statistically significant differences between the ketamine and benzodiazepine cohorts for psychiatric inpatient admission (6.8% vs. 2.4%, difference = 4.3%, 95% CI = -2% to 12%, p = 0.23) or ED psychiatric evaluation (8.6% vs. 15%, difference = -6.8%, 95% CI = -18% to 5%, p = 0.23). Patients with schizophrenia who received ketamine did not require psychiatric inpatient admission (17% vs. 10%, difference = 6.7%, 95% CI = -46% to 79%, p = 0.63) or ED psychiatric evaluation (17% vs. 50%, difference = -33%, 95% CI = -100% to 33%, p = 0.55) significantly more than those who received benzodiazepines, although the subgroup was small (n = 16). While there was no significant difference in the nonpsychiatric admission rate between the ketamine and benzodiazepine cohorts (35% vs. 51%, p = 0.082), nonpsychiatric admissions in the benzodiazepine cohort were largely driven by intubation (63% vs. 3.8%, difference = 59%, 95% CI = 38% to 79%, p < 0.001).Conclusions: Administration of prehospital ketamine for severe agitation was not associated with an increase in the rate of psychiatric evaluation in the emergency department or psychiatric inpatient admission when compared with benzodiazepine treatment, regardless of the patient's psychiatric history.A cute, undifferentiated agitation is a commonly encountered problem in the prehospital and emergency department (ED) setting. 1,2 When verbal deescalation is ineffective, pharmacologic management may be required to ensure safety for both patients and providers. Traditional pharmacologic treatments for From the

Variations in the care of agitated patients in Australia and New Zealand ambulance services

“…Lebin et al . found no differences in admissions or psychiatric evaluations between patients who received ketamine compared to benzodiazepines in the ED, although the sample size was relatively small and unable to account for safety . There is limited evidence regarding the optimum dose for ketamine, reflected in the wide dose range in the CPGs.…”

Exploring bias in restraint use: Four strategies to mitigate bias in care of the agitated patient in the emergency department

“…6,38 To our best knowledge, there are only F I G U R E 1 Multilevel systemic approach to mitigating bias in agitation management in the ED a few studies that look for meaningful demographic group differences in restraint use in the ED. [5][6][7] To better understand and improve care of agitated patients, more collective data are needed about patient, provider, and situational variabilities which may influence care. An example of this include the National Database of Nursing Quality Indicators (NDNQI), the largest database of unit-level, nurse-sensitive performance data in the United States, collecting data on nursing ratio and restraint use from 869 U.S. hospitals on the care of more than 923,000 patients from 2006 to 2010.…”

“…5-7 Several recent regional studies have found that Black patients were 13% to 22% more likely to be restrained when compared to White patients, suggesting racial differences in chemical and physical restraint use. [5][6][7] Although agitation is a common occurrence, the specific clinical scenarios can be as unique as the patients themselves. The management can be nuanced, oftentimes aimed at addressing potential threats of violence for staff as well as other patients.…”

Ketamine Use in Prehospital and Hospital Treatment of the Acute Trauma Patient: A Joint Position Statement

“…6. Although previously discouraged, ketamine use can be considered in trauma patients with schizophrenia as there does not appear to be an associated increase in the incidence of psychosis (7,8).…”