Out-of-hospital ketamine: review of a growing trend in patient care

Fixed dose ketamine for prehospital management of hyperactive delirium with severe agitation

INTRODUCTION

Patients exhibiting signs of hyperactive delirium with severe agitation (HDSA) may require sedating medications for stabilization and safe transport to the hospital. Determining the patient's weight and calculating the correct weight-based dose may be challenging in an emergency. A fixed dose ketamine protocol is an alternative to the traditional weight-based administration, which may also reduce dosing errors. The objective of this study was to evaluate the frequency and characteristics of adverse events following pre-hospital ketamine administration for HDSA.

METHODS

Emergency Medical Services (EMS) records from four agencies were searched for prehospital ketamine administration. Cases were included if a 250 mg dose of ketamine was administered on standing order to an adult patient for clinical signs consistent with HDSA. Protocols allowed for a second 250 mg dose of ketamine if the first dose was not effective. Both the 250 mg initial dose and the total prehospital dose were analyzed for weight based dosing and adverse events.

RESULTS

Review of 132 cases revealed 60 cases that met inclusion criteria. Patients' median weight was 80 kg (range: 50-176 kg). No patients were intubated by EMS, one only requiring suction, three required respiratory support via bag valve mask (BVM). Six (10%) patients were intubated in the emergency department (ED) including the three (5%) supported by EMS via BVM, three (5%) others who were sedated further in the ED prior to requiring intubation. All six patients who were intubated were discharged from the hospital with a Cerebral Performance Category (CPC) 1 score. The weight-based dosing equivalent for the 250 mg initial dose (OR: 2.62, CI: 0.67-10.22) and the total prehospital dose, inclusive of the 12 patients that were administered a second dose, (OR: 0.74, CI: 0.27, 2.03), were not associated with the need for intubation.

CONCLUSION

The 250 mg fixed dose of ketamine was not >5 mg/kg weight-based dose equivalent for all patients in this study. Although a second 250 mg dose of ketamine was permitted under standing orders, only 12 (20%) of the patients were administered a second dose, none experienced an adverse event. This indicates that the 250 mg initial dose was effective for 80% of the patients. Four patients with prehospital adverse events likely related to the administration of ketamine were found. One required suction, three (5%) requiring BVM respiratory support by EMS were subsequently intubated upon arrival in the ED. All 60 patients were discharged from the hospital alive. Further research is needed to determine an optimal single administration dose for ketamine in patients exhibiting signs of HDSA, if employing a standardized fixed dose medication protocol streamlines administration, and if the fixed dose medication reduces the occurrence of dosage errors.

Hyperactive Delirium with Severe Agitation

Hyperactive delirium with severe agitation is a clinical syndrome of altered mental status, psychomotor agitation, and a hyperadrenergic state. The underlying pathophysiology is variable and often results from sympathomimetic abuse, psychiatric disease, sedative-hypnotic withdrawal, and metabolic derangement. Patients can go from a combative state to periarrest with little warning. Safety of the patient and of the medical providers is paramount and the emergency department should be prepared to manage these patients with adequate staffing, restraints, and pharmacologic sedatives. Treatment with benzodiazepines, antipsychotics, or ketamine is recommended, followed by airway protection, supportive measures, and cooling of hyperthermia.

The Pain Management of Trauma Patients in the Emergency Department

The vast majority of injured patients suffer from pain. Systematic assessment of pain on admission to the emergency department (ED) is a cornerstone of translating the best treatment strategies for patient care into practice. Pain must be measured with severity scales that are validated in clinical practice, including for specific populations (such as children and older adults). Although primary care ED of trauma patients focuses on resuscitation, diagnosis and treatment, pain assessment and management remains a critical element as professionals are not prepared to provide effective and early therapy. To date, most EDs have pain assessment and management protocols that take into account the patient's hemodynamic status and clinical condition and give preference to non-pharmacological approaches where possible. When selecting medications, the focus is on those that are least disruptive to hemodynamic status. Pain relief may still be necessary in hemodynamically unstable patients, but caution should be exercised, especially when using opioids, as absorption may be impaired or shock may be exacerbated. The analgesic dose of ketamine is certainly an attractive option. Fentanyl is clearly superior to other opioids in initial resuscitation and treatment as it has minimal effects on hemodynamic status and does not cause central nervous system depression. Inhaled analgesia techniques and ultrasound-guided nerve blocks are also increasingly effective solutions. A multimodal pain approach, which involves the use of two or more drugs with different mechanisms of action, plays an important role in the relief of trauma pain. All EDs must have policies and promote the adoption of procedures that use multimodal strategies for effective pain management in all injured patients.

Nebulized Ketamine for Analgesia in the Prehospital Setting: A Case Series

We report the initial seven patients treated with nebulized ketamine for moderate to severe pain, via breath-actuated nebulizer, in an urban, ground-based emergency medical services (EMS) system. Ketamine for analgesia in the emergency setting has become widespread over the past decade. The addition of a non-parenteral, inexpensive, and well-tolerated ketamine delivery option is extremely desirable. We believe these initial data demonstrate promising pain reduction coupled with minimal side effects, indicating a potential role for nebulized ketamine in EMS.

Prehospital Use of Ketamine versus Benzodiazepines for Sedation among Pediatric Patients with Behavioral Emergencies

INTRODUCTION

Ketamine is an emerging alternative sedation agent for prehospital management of agitation, yet research is limited regarding its use for children. Our objective was to compare the effectiveness and safety of ketamine and benzodiazepines when used for emergent prehospital sedation of pediatric patients with behavioral emergencies.

METHODS

We performed a retrospective review of 9-1-1 EMS records from the 2019-2020 ESO Data Collaborative research datasets. We included patients ≤18 years of age who received ketamine or benzodiazepines for EMS primary and secondary impressions indicating behavioral conditions. We excluded patients with first Glasgow Coma Scale (GCS) scores ≤8, those receiving ketamine or benzodiazepines prior to EMS arrival, those receiving both ketamine and benzodiazepines, and interfacility transfers. Effectiveness outcomes included general clinician assessment of improvement, decrease in GCS, and administration of a subsequent sedative. Safety outcomes included mortality; advanced airway placement; ventilatory assistance without advanced airway placement; or marked sedation (GCS ≤8). Chi-square and t-tests were used to compare the ketamine and benzodiazepines groups.

RESULTS

Of 57,970 pediatric patients with behavioral complaints and GCS scores >8, 1,539 received ketamine (13.3%, n = 205) or a benzodiazepine (86.7%, n = 1,334). Most patients were ≥12 years old (89.2%, n = 1,372), predominantly Caucasian (48.3%, n = 744), and were equally distributed by sex (49.7% male, n = 765). First treatment with ketamine was associated with a greater likelihood of improvement (88.8% vs 70.5%, p < 0.001) and a greater average GCS reduction compared to treatment with benzodiazepines (-2.5 [SD:4.0] vs -0.3 [SD:1.7], p < 0.001). Fewer patients who received ketamine received subsequent medication compared to those who received benzodiazepines (12.2% vs 27.0%, p < 0.001). Marked sedation was more frequent with ketamine than benzodiazepines (28.8% vs 2.9%, p < 0.001). Provision of ventilatory support (1.5% vs 0.5%, p = 0.14) and advanced airway placement (1.0% vs 0.2%, p = 0.09) were similar between ketamine and benzodiazepine groups. No prehospital deaths were reported.

CONCLUSION

In this pediatric cohort, prehospital sedation with ketamine was associated with greater patient improvement, less subsequent sedative administration, and greater sedation compared to benzodiazepines. Though we identified low rates of adverse events in both groups, ketamine was associated with more instances of marked sedation, which bears further study.

Patterns of Palliation: A Review of Casualties That Received Pain Management Before Reaching Role 2 in Afghanistan

INTRODUCTION

Battlefield pain management changed markedly during the first 20 years of the Global War on Terror. Morphine, long the mainstay of combat analgesia, diminished in favor of fentanyl and ketamine for military pain control, but the options are not hemodynamically or psychologically equivalent. Understanding patterns of prehospital analgesia may reveal further opportunities for combat casualty care improvement.

MATERIALS AND METHODS

Using Department of Defense Trauma Registry data for the Afghanistan conflict from 2005 to 2018, we examined 2,402 records of prehospital analgesia administration to assess temporal trends in medication choice and proportions receiving analgesia, including subanalysis of a cohort screened for an indication with minimal contraindication for analgesia. We further employed frequency matching to explore the presence of disparities in analgesia by casualty affiliation.

RESULTS

Proportions of documented analgesia increased throughout the study period, from 0% in 2005 to 70.6% in 2018. Afghan casualties had the highest proportion of documented analgesia (53.0%), versus U.S. military (31.9%), civilian/other (23.3%), and non-U.S. military (19.3%). Fentanyl surpassed morphine in the frequency of administration in 2012. The median age of those receiving ketamine was higher (30 years) than those receiving fentanyl (26 years) or nonsteroidal anti-inflammatory drugs (23 years). Among the frequency-matched subanalysis, the odds ratio for ketamine administration with Afghan casualties was 1.84 (95% CI, 1.30-2.61).

CONCLUSIONS

We observed heterogeneity of prehospital patient care across patient affiliation groups, suggesting possible opportunities for improvement toward an overall best practice system. General increase in documented prehospital pain management likely reflects efforts toward complete documentation, as well as improved options for analgesia. Current combat casualty care documentation does not include any standardized pain scale.

Intubation Rates following Prehospital Administration of Ketamine for Acute Agitation: A Systematic Review and Meta-Analysis

BACKGROUND

Ketamine is a fast-acting, dissociative anesthetic with a favorable adverse effect profile that is effective for managing acute agitation as a chemical restraint in the prehospital and emergency department (ED) settings. However, some previously published individual studies have reported high intubation rates when ketamine was administered prehospitally.

OBJECTIVE

This systematic review aims to determine the rate and settings in which intubation following prehospital administration of ketamine for agitation is occurring, as well as associated indications and adverse events.

METHODS

We searched PubMed, Scopus, Ovid MEDLINE, Embase, CINAHL Plus, PsycINFO, the Cochrane Library, ClinicalTrials.gov, OpenGrey, Open Access Theses and Dissertation, and Google Scholar from the earliest possible date until 13/February/2022. Inclusion criteria required studies to describe agitated patients who received ketamine in the prehospital setting as a first-line drug to control acute agitation. Reference lists of appraised studies were screened for additional relevant articles. Study quality was assessed using the Newcastle-Ottawa quality assessment scale. Synthesis of results was completed via meta-analysis, and the GRADE tool was used for certainty assessment.

RESULTS

The search yielded 1466 unique records and abstracts, of which 50 full texts were reviewed, resulting in 18 being included in the analysis. All studies were observational in nature and 15 were from USA. There were 3476 patients in total, and the overall rate of intubation was 16% (95% confidence interval [CI] = 8%-26%). Most intubations occurred in the ED. Within the studies, the prehospital intubation rate ranged from 0% to 7.9% and the ED intubation rate ranged from 0 to 60%. The overall pooled prehospital intubation rate was 1% (95% CI = 0%-2%). The overall pooled ED intubation rate was 19% (95% CI = 11%-30%). The most common indications for intubation were for airway protection and respiratory depression/failure.

CONCLUSIONS

There is wide variation in intubation rates between and within studies. The majority of intubations performed following prehospital administration of ketamine for agitation took place in the ED.

Current status of perioperative hypnotics, role of benzodiazepines, and the case for remimazolam: a narrative review

Anaesthesiologists and non-anaesthesiologist sedationists have a limited set of available i.v. hypnotics, further reduced by the withdrawal of thiopental in the USA and its near disappearance in Europe. Meanwhile, demand for sedation increases and new clinical groups are using what traditionally are anaesthesiologists' drugs. Improved understanding of the determinants of perioperative morbidity and mortality has spotlighted hypotension as a potent cause of patient harm, and practice must be adjusted to respect this. High-dose propofol sedation may be harmful, and a critical reappraisal of drug choices and doses is needed. The development of remimazolam, initially for procedural sedation, allows reconsideration of benzodiazepines as the hypnotic component of a general anaesthetic even if their characterisation as i.v. anaesthetics is questionable. Early data suggest that a combination of remimazolam and remifentanil can induce and maintain anaesthesia. Further work is needed to define use cases for this technique and to determine the impact on patient outcomes.