Ketamine for Prehospital Pain Management Does Not Prolong Emergency Department Length of Stay

Evaluation of the Use of Ketamine in Prehospital Seizure Management: A Retrospective Review of the ESO Database

OBJECTIVES

Benzodiazepines are the primary antiseizure medication used by Emergency Medical Services (EMS) for seizures. Available literature in the United States and internationally shows 30% to 40% of seizures do not terminate with benzodiazepines called benzodiazepine refractory status epilepticus (BRSE). Ketamine is a potential treatment for BRSE due to its unique pharmacology. However, its application in the prehospital setting is mostly documented in case reports. Little is known about its use by EMS professionals for seizure management, whether as initial treatment or for BRSE, creating an opportunity to describe its current use and inform future research.

METHODS

We performed a retrospective review of 9-1-1 EMS encounters with a primary or secondary impression of seizure using the ESO Data Collaborative from 2018 to 2021. We isolated encounters during which ketamine was administered. We excluded medication administrations prior to EMS arrival and encounters without medication administration. Subgroup analysis was performed to control for airway procedure as an indication for ketamine administration. We also evaluated for co-administration with other antiseizure medications, dose and route of administration, and response to treatment.

RESULTS

We identified 99,576 encounters that met inclusion. There were 2,531/99,576 (2.54%) encounters with ketamine administration and 50.7% (1,283/2,531) received ketamine without an airway procedure. There were 616 cases (48%, 616/1,283) where ketamine was given without another antiseizure medication (ASM) and without any airway procedure. The remaining 667 (52%) cases received ketamine with at least one other ASM, most commonly midazolam (89%, 593/667). Adjusted for the growth in the ESO dataset, ketamine use by EMS professionals during encounters for seizures without an airway procedure increased from 0.90% (139/15,375) to 1.45% (416/28,651) an increase of 62% over the study period.

CONCLUSIONS

In this retrospective review of the ESO Data Collaborative, ketamine administration for seizure encounters without an airway procedure increased over the study period, both as a single agent and with another ASM. Most ketamine administrations were for adult patients in the south and in urban areas. The frequency of BRSE, the need for effective treatment, and the growth in ketamine use warrant prospective prehospital research to evaluate the value of ketamine in prehospital seizure management.

Ketamine intolerance in patients on enhanced recovery after surgery protocols undergoing colorectal operations

BACKGROUND

Ketamine is used in enhanced recovery after surgery (ERAS) protocols because of its beneficial antihyperalgesic and antitolerance effects. However, adverse effects such as hallucinations, sedation, and diplopia could limit ketamine's utility. The main objective of this study was to identify rates of ketamine side effects in postoperative patients after colorectal surgery and, secondarily, to compare short-term outcomes between patients receiving ketamine analgesia and controls.

METHODS

This was a retrospective observational cohort study. Subjects were adults who underwent ERAS protocol-guided colorectal surgery at a large, integrated health system. Patients were grouped into ketamine-receiving and preketamine cohorts. Patients receiving ketamine were divided into tolerant and intolerant groups. Propensity score-adjusted models tested multivariate associations of ketamine tolerance/intolerance vs control group.

RESULTS

A total of 732 patients underwent colorectal surgery within the ERAS program before ketamine's introduction (control). After ketamine's introduction, 467 patients received the medication. Intolerance was seen in 29% of ketamine recipients, and the most common side effect was diplopia. Demographics and surgical variables did not differ between cohorts. Multivariate models revealed no significant differences in hospital stays. Pain scores in the first 24 hours after surgery were slightly higher in patients receiving ketamine. Opiate consumption after surgery was lower for both ketamine tolerant and ketamine intolerant cohorts than for controls.

CONCLUSION

Rates of ketamine intolerance are high, which can limit its use and potential effectiveness. Ketamine analgesia significantly reduced opiate consumption without increasing hospital stays after colorectal surgery, regardless of whether it was tolerated.

Ambulance Transport Destinations In The US Differ By Patient Race And Ethnicity

Patients in the US belonging to racial or ethnic minority groups often receive medical care in different hospitals than White patients, which contributes to health care disparities. We explored whether ambulance transport destinations contribute to this phenomenon. Using a national emergency medical services research data set for calendar year 2020, we made within-ZIP code comparisons of the transport destinations for White patients and non-White patients transported by ambulance from emergency scenes. We used the dissimilarity index to measure transport destination discordances and decided a priori that a more than 5 percent difference in transport destinations (that is, dissimilarity index >0.05) would be practically meaningful. We found meaningful differences in the destination hospitals for White and non-White patients transported by ambulance from locations in the same ZIP code. The median ZIP code dissimilarity index was 0.08, 64 percent of ZIP codes had a dissimilarity index above 0.05, and 61 percent of patients were transported from ZIP codes with a dissimilarity index above 0.05. Forty-one percent of ZIP codes had a dissimilarity index above 0.10, and one-third of the patients were transported from those ZIP codes. These data indicate that ambulance transport destinations contribute to discordances in where White and non-White patients receive medical care.

Out-of-Hospital Ketamine: Indications for Use, Patient Outcomes, and Associated Mortality

STUDY OBJECTIVE

To describe out-of-hospital ketamine use, patient outcomes, and the potential contribution of ketamine to patient death.

METHODS

We retrospectively evaluated consecutive occurrences of out-of-hospital ketamine administration from January 1, 2019 to December 31, 2019 reported to the national ESO Data Collaborative (Austin, TX), a consortium of 1,322 emergency medical service agencies distributed throughout the United States. We descriptively assessed indications for ketamine administration, dosing, route, transport disposition, hypoxia, hypercapnia, and mortality. We reviewed cases involving patient death to determine whether ketamine could be excluded as a potential contributing factor.

RESULTS

Indications for out-of-hospital ketamine administrations in our 11,291 patients were trauma/pain (49%; n=5,575), altered mental status/behavioral indications (34%; n=3,795), cardiovascular/pulmonary indications (13%; n=1,454), seizure (2%; n=248), and other (2%; n=219). The highest median dose was for altered mental status/behavioral indications at 3.7 mg/kg (interquartile range, 2.2 to 4.4 mg/kg). Over 99% of patients (n=11,274) were transported to a hospital. Following ketamine administration, hypoxia and hypercapnia were documented in 8.4% (n=897) and 17.2% (n=1,311) of patients, respectively. Eight on-scene and 120 in-hospital deaths were reviewed. Ketamine could not be excluded as a contributing factor in 2 on-scene deaths, representing 0.02% (95% confidence interval 0.00% to 0.07%) of those who received out-of-hospital ketamine. Among those with in-hospital data, ketamine could not be excluded as a contributing factor in 6 deaths (0.3%; 95% confidence interval 0.1% to 0.7%).

CONCLUSION

In this large sample, out-of-hospital ketamine was administered for a variety of indications. Patient mortality was rare. Ketamine could not be ruled out as a contributing factor in 8 deaths, representing 0.07% of those who received ketamine.