Comparison of the Effects of Ketamine and Morphine on Performance of Representative Military Tasks

Effects of melancholic features on positive and negative suicidal ideation in patients with treatment-resistant depression and strong suicidal ideation receiving low-dose ketamine infusion

The role of melancholic features on the antisuicidal effect of 0.5 mg/kg ketamine infusion has remained unclear in patients with treatment-resistant depression (TRD) and strong suicidal ideation (SI). Whether ketamine diminishes suicidal ideation in patients with TRD-SI was also unknown. We enrolled 84 patients with TRD-SI, including 27 with melancholic features and 57 without, and then randomly administered a single infusion of 0.5 mg/kg ketamine or 0.045 mg/kg midazolam. The clinician-rated Montgomery-Åsberg Depression Rating Scale (MADRS) item 10, Columbia Suicide Severity Rating Scale-Ideation Severity Subscale (CSSRS-ISS), and self-reported Positive and Negative Suicide Ideation Inventory (PANSI) were used to assess suicidal symptoms from baseline to day 7. Generalized estimating equation models showed that only patients without melancholic features (MADRS item 10: infusion group effect, p = 0.017; CSSRS-ISS: infusion group × time effect, p = 0.008; PANSI-negative suicidal ideation: infusion group effect, p = 0.028) benefited from the antisuicidal effect of low-dose ketamine. The PANSI-positive ideation scores were higher in the ketamine group than in the midazolam group (p = 0.038) for patients with melancholic features. Additional studies are necessary to clarify the neuromechanisms underlying the ketamine-related positive effect against SI and antisuicidal effects among patients with TRD-SI. Additional studies are necessary to clarify the neuromechanisms underlying the ketamine-related positive effect against SI and antisuicidal effects among patients with TRD-SI.

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.

Battlefield Pain Summit 2022: Expert Consensus Statements

BACKGROUND

Battlefield pain occurs in combat casualties who suffer multiple severe injuries The nature of battlefield scenarios requires a distinct approach to battlefield pain research. A Battlefield Pain Summit was thus convened to identify shortcomings in current understanding of battlefield pain management, review the current state of battlefield pain research, and shape the direction of future research.

METHODS

On 10-11 January 2022, a hybrid in-person and virtual meeting hosted by the United States Army Institute of Surgical Research (USAISR) defined research priorities for the Combat Casualty Care Research Program's Battlefield Pain research portfolio. Summit participants identified key focus areas under the umbrella of battlefield pain research: battlefield injury patterns; use of ketamine and non-opioid analgesics; analgesic delivery systems; the impact of analgesia on performance, cognition, and survival; training methods; battlefield regional anesthesia; and research models. Preliminary statements presented during the summit refined and rank ordered through a Delphi process.

RESULTS

A total of seven statements achieved consensus addressing ideal analgesic properties, delivery systems, operational performance concerns, and pain training. Ketamine was identified as safe and effective for battlefield use, and further research into non-opioid analgesics represented a high priority.

CONCLUSIONS

The seven consensus statements that emerged from this Battlefield Pain Summit serve as a template to define the near-term research priorities for military-specific battlefield pain research.

Ketamine Use in Operation Enduring Freedom

INTRODUCTION

Ketamine is a dissociative anesthetic increasingly used in the prehospital and battlefield environment. As an analgesic, it has been shown to have comparable effects to opioids. In 2012, the Defense Health Board advised the Joint Trauma System to update the Tactical Combat Casualty Care Guidelines to include ketamine as an acceptable first line agent for pain control on the battlefield. The goal of this study was to investigate trends in the use of ketamine during Operation Enduring Freedom (OEF) and Operation Freedom's Sentinel (OFS) during the years 2011-2016.

MATERIALS AND METHODS

A retrospective review of Department of Defense Trauma Registry (DoDTR) data was performed for all patients receiving ketamine during OEF/OFS in 2011-2016. Prevalence of ketamine use, absolute use, mechanism of injury, demographics, injury severity score, provider type, and co-administration rates of various medications and blood products were evaluated.

RESULTS

Total number of administrations during the study period was 866. Ketamine administration during OEF/OFS increased during the years 2011-2013 (28 patient administrations in 2011, 264 administrations in 2012, and 389 administrations in 2013). A decline in absolute use was noted from 2014 to 2016 (98 administrations in 2014, 41 administrations in 2015, and 46 administrations in 2016). The frequency of battlefield ketamine use increased from 0.4% to 11.3% for combat injuries sustained in OEF/OFS from 2011 to 2016. Explosives (51%) and penetrating trauma (39%) were the most common pattern of injury in which ketamine was administered. Ketamine was co-administered with fentanyl (34.4%), morphine (26.2%), midazolam (23.1%), tranexamic acid (12.3%), plasma (10.3%), and packed red blood cells (18.5%).

CONCLUSIONS

This study demonstrates increasing use of ketamine by the U.S. Military on the battlefield and effectiveness of clinical practice guidelines in influencing practice patterns.

Prehospital Use of Ketamine in the Combat Setting: A Sub-Analysis of Patients With Head Injuries Evaluated in the Prospective Life Saving Intervention Study

Objectives

Ketamine is used as an analgesic for combat injuries. Ketamine may worsen brain injury, but new studies suggest neuroprotection. Our objective was to report the outcomes of combat casualties with traumatic brain injury (TBI) who received prehospital ketamine.

Methods

This was a post hoc, sub-analysis of a larger prospective, multicenter study (the Life Saving Intervention study [LSI]) evaluating prehospital interventions performed in Afghanistan. A DoD Trauma Registry query provided disposition at discharge and outcomes to be linked with the LSI data.

Results

For this study, we enrolled casualties that were suspected to have TBI (n = 160). Most were 26-year-old males (98%) with explosion-related injuries (66%), a median injury severity score of 12, and 5% mortality. Fifty-seven percent (n = 91) received an analgesic, 29% (n = 46) ketamine, 28% (n = 45) other analgesic (OA), and 43% (n = 69) no analgesic (NA). The ketamine group had more pelvic injuries (P = 0.0302) and tourniquets (P = 0.0041) compared to OA. In comparison to NA, the ketamine group was more severely injured and more likely to require LSI procedures, yet, had similar vital signs at admission and disposition at discharge.

Conclusions

We found that combat casualties with suspected TBI that received prehospital ketamine had similar outcomes to those that received OAs or NAs despite injury differences.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.