Pain management in the wilderness and operational setting

Wilderness Medical Society Clinical Practice Guidelines for the Treatment of Acute Pain in Austere Environments: 2024 Update

The Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the management of pain in austere environments. Recommendations are graded based on the quality of supporting evidence as defined by criteria put forth by the American College of Chest Physicians. This is an update of the 2014 version of the "WMS Practice Guidelines for the Treatment of Acute Pain in Remote Environments" published in Wilderness & Environmental Medicine 2014; 25:41-49.

Ketamine decreased opiate use in US military combat operations from 2010 to 2019

BACKGROUND

Ketamine is a dissociative anaesthetic currently used in a variety of healthcare applications. Effects are dose dependent and cause escalating levels of euphoria, analgesia, dissociation and amnesia. Ketamine can be given via intravenous, intramuscular, nasal, oral and aerosolised routes. A 2012 memorandum and the 2014 Tactical Combat Casualty Care (TCCC) guidelines included ketamine as part of the 'Triple Option' for analgesia. This study investigated the effect of ketamine adoption by the US military TCCC guidelines on opioid use between 2010 and 2019.

METHODS

This was a retrospective review of deidentified Department of Defense Trauma Registry data. The study was approved by the Institutional Review Board of Naval Medical Center San Diego (NMCSD) and facilitated by a data sharing agreement between NMCSD and the Defense Health Agency. Patient encounters from all US military operations from January 2010 to December 2019 were queried. All administrations of any pain medications via any route were included.

RESULTS

5965 patients with a total of 8607 pain medication administrations were included. Between 2010 and 2019, the yearly percentage of ketamine administrations rose from 14.2% to 52.6% (p<0.001). The percentage of opioid administrations decreased from 85.8% to 47.4% (p<0.001). Among the 4104 patients who received a single dose of pain medication, the mean Injury Severity Score for those who received ketamine was higher than for those who received an opioid (mean=13.1 vs 9.8, p<0.001).

CONCLUSION

Military opioid use declined as ketamine use increased over 10 years of combat. Ketamine is generally used first for more severely injured patients and has increasingly been employed by the US military as the primary analgesic for combat casualties.

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 Mountain Rescue: A Survey of Emergency Physicians of a Single-Center Alpine Helicopter-Based Emergency Service

INTRODUCTION

Although ketamine use in emergency medicine is widespread, studies investigating prehospital use are scarce. Our goal was to assess the self-reported modalities of ketamine use, knowledge of contraindications, and occurrence of adverse events associated with its use by physicians through a prospective online survey.

METHODS

The survey was administered to physicians working for Air-Glaciers, a Swiss alpine helicopter-based emergency service, and was available between September 24 and November 23, 2018. We enrolled 39 participants (participation rate of 87%) in our study and collected data regarding their characteristics, methods of ketamine use, knowledge of contraindications, and encountered side effects linked to the administration of ketamine. We also included a clinical scenario to investigate an analgesic strategy.

RESULTS

Ketamine was considered safe and judged irreplaceable by most physicians. The main reason for ketamine use was acute analgesia during painful procedures, such as manipulation of femur fractures. The doses of ketamine administered with or without fentanyl ranged from 0.2 to 0.7 mg·kg^-1 intravenously. Most physicians reported using fentanyl and midazolam along with ketamine. The median dose of midazolam was 2 (interquartile range 1-2) mg for a 70-kg adult. Monitoring and oxygen administration were used infrequently. Hallucinations were the most common adverse events. Knowledge of ketamine contraindications was poor.

CONCLUSIONS

Ketamine use was reported by mountain rescue physicians to be safe and useful for acute analgesia. Most physicians use fentanyl and midazolam along with ketamine. Adverse neuropsychiatric events were rare. Knowledge regarding contraindications to the administration of ketamine should be improved.

Femoral nerve blocks for the treatment of acute pre-hospital pain: A systematic review with meta-analysis

BACKGROUND

Pain management is one of the most important interventions in the emergency medical services. The femoral nerve block (FNB) is, among other things, indicated for pre- and post-operative pain management for patients with femoral fractures but its role in the pre-hospital setting has not been determined. The aim of this review was to assess the effect and safety of the FNB in comparison to other forms of analgesia (or no treatment) for managing acute lower extremity pain in adult patients in the pre-hospital setting.

METHODS

A systematic review (PROSPERO registration (CRD42018114399)) was conducted. The Cochrane and GRADE methods were used to assess outcomes. Two authors independently reviewed each study for eligibility, extracted the data and performed risk of bias assessments.

RESULTS

Four studies with a total of 252 patients were included. Two RCTs (114 patients) showed that FNB may reduce pain more effectively than metamizole (mean difference 32 mm on a 100 mm VAS (95% CI 24 to 40)). One RCT (48 patients) compared the FNB with lidocaine and magnesium sulphate to FNB with lidocaine alone and was only included here for information regarding adverse effects. One case series included 90 patients. Few adverse events were reported in the included studies. The certainty of evidence was very low. We found no studies comparing FNB to inhaled analgesics, opioids or ketamine.

CONCLUSIONS

Evidence regarding the effectiveness and adverse effects of pre-hospital FNB is limited. Studies comparing pre-hospital FNB to inhaled analgesics, opioids or ketamine are lacking.

Ketamine as a Prehospital Analgesic: A Systematic Review

OBJECTIVE

Analgesia in the prehospital setting is an extremely important, yet controversial topic. Ketamine, a N-methyl D-aspartate (NMDA) receptor antagonist, has been commonly used in the prehospital setting, including recommendations by the US Department of Defense and by the Royal Australian College of Pain Medicine, despite the paucity of high-level evidence.

METHODS

Accordingly, a review of the literature was conducted using several electronic medical literature databases from the earliest available records to the time at which the search was conducted (October 2018).

RESULTS

The search strategy yielded a total of 707 unique papers, of which 43 were short-listed for full review, and ultimately, ten papers were identified as meeting all the relevant inclusion criteria. The included studies varied significantly in the prehospital context and in the means of administering ketamine. There was only low-grade evidence that ketamine offered a safe and effective analgesia when used as the only analgesic, and only low-grade evidence that it was as effective as alternative opioid options. However, there was moderate evidence that co-administration of ketamine with morphine may improve analgesic efficacy and reduce morphine requirement.

CONCLUSIONS

Overall, ketamine as a prehospital analgesic may be best used in combination with opioids to reduce opioid requirement. It is suggested that future studies should use a standardized approach to measuring pain reduction. Future studies should also investigate short-term side effects and long-term complications or benefits of prehospital ketamine.

Low-dose intravenous ketamine versus intravenous ketorolac in pain control in patients with acute renal colic in an emergency setting: a double-blind randomized clinical trial

BACKGROUND

This study was conducted to compare the effectiveness of low-dose ketamine versus ketorolac in pain control in patients with acute renal colic presenting to the emergency department (ED).

METHODS

This is a double-blind randomized clinical trial. The initial pain severity was assessed using the numerical rating scale (NRS). Then, ketamine or ketorolac was administered intravenously at a dose of 0.6 mg/kg and 30 mg respectively. The pain severity and adverse drug reactions were recorded 5, 15, 30, 60, and 120 min thereafter.

RESULTS

The data of 62 subjects in the ketamine group and 64 patients in the ketorolac group were analyzed. The mean age of the patients was 34.2 ± 9.9 and 37.9 ± 10.6 years in the ketamine and ketorolac group, respectively. There was no significant difference in the mean NRS scores at each time point, except for the 5 min, between the two groups. Despite a marked decrease in pain severity in the ketamine group from drug administration at the 5 min, a slight increase in pain was observed from the 5 min to the 15 min. The rate of adverse drug reactions, including dizziness (P = 0.001), agitation (P = 0.002), increased systolic blood pressure (> 140 mmHg), and diastolic blood pressure (> 90 mmHg) was higher in the ketamine group.

CONCLUSIONS

Low dose ketamine is as effective as ketorolac in pain management in patients with renal colic presenting to the ED. However, it is associated with a higher rate of adverse drug reactions.

A Survey of Wilderness Medicine Analgesia Practice Patterns

INTRODUCTION

In 2014, the Wilderness Medical Society (WMS) published guidelines for the treatment of acute pain in remote settings. We surveyed wilderness medicine providers on self-reported analgesia prescribing practices.

METHODS

We conducted a prospective, anonymous survey. Respondents were recruited from the WMS annual symposium in 2016. All willing attendees were included.

RESULTS

During the symposium, we collected a total of 124 surveys (68% response rate). Respondent age was 42±12 (24-79) years (mean±SD with range), 58% were male, and 69% reported physician-level training. All respondents had medical training of varying levels. Of the physicians reporting a specialty, emergency medicine (59%, n=51), family medicine (13%, n=11), and internal medicine (8%, n=7) were reported most frequently. Eighty-one (65%) respondents indicated they prefer a standardized pain assessment tool, with the 10-point numerical rating scale being the most common (54%, n=67). Most participants reported preferring oral acetaminophen (81%, n=101) or nonsteroidal anti-inflammatory drugs (NSAID) (91%, n=113). Of those preferring NSAID, most reported administering acetaminophen as an adjunct (82%, n=101). Ibuprofen was the most frequently cited NSAID (71%, n=88). Of respondents who preferred opioids, the most frequently preferred opioid was oxycodone (26%, n=32); a lower proportion of respondents reported preferring oral transmucosal fentanyl citrate (9%, n=11). Twenty-five (20%, n=25) respondents preferred ketamine.

CONCLUSIONS

Wilderness medicine practitioners prefer analgesic agents recommended by the WMS for the treatment of acute pain. Respondents most frequently preferred acetaminophen and NSAIDs.

Battlefield Analgesia in Tactical Combat Casualty Care

At the start of the Afghanistan conflict, battlefield analgesia for US military casualties was achieved primarily through the use of intramuscular (IM) morphine. This is a suboptimal choice, since IM morphine is slow-acting, leading to delays in effective pain relief and the risk of overdose and death when dosing is repeated in order to hasten the onset of analgesia. Advances in battlefield analgesia, pioneered initially by Tactical Combat Casualty Care (TCCC), and the Army's 75th Ranger Regiment, have now been incorporated into the Triple-Option Analgesia approach. This novel strategy has gained wide acceptance in the US military. It calls for battlefield analgesia to be achieved using 1 or more of 3 options depending on the casualty's status: 1) the meloxicam and acetaminophen in the combat wound medication pack (CWMP) for casualties with relatively minor pain that are still able to function effectively as combatants if their sensorium is not altered by analgesic medications; 2) oral transmucosal fentanyl citrate (OTFC) for casualties who have moderate to severe pain, but who are not in hemorrhagic shock or respiratory distress, and are not at significant risk for developing either condition; or 3) ketamine for casualties who have moderate to severe pain, but who are in hemorrhagic shock or respiratory distress or are at significant risk for developing either condition. Ketamine may also be used to increase analgesic effect for casualties who have previously been given opioid medication. The present paper outlines the evolution and evidence base for battlefield analgesia as currently recommended by TCCC. It is not intended to be a comprehensive review of all prehospital analgesic options.

Wilderness Medical Society practice guidelines for the treatment of acute pain in remote environments: 2014 update

The Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for the management of pain in austere environments. Recommendations are graded on the basis of the quality of supporting evidence as defined by criteria put forth by the American College of Chest Physicians. This is an updated version of the original WMS Practice Guidelines for the Treatment of Acute Pain in Remote Environments published in Wilderness & Environmental Medicine 2014;25(1):41-49.

Managing moderate and severe pain in mountain rescue

AIMS

We aimed to describe evidence-based options for prehospital analgesia, and to offer practical advice to physicians and nonphysicians working in mountain rescue.

METHODS

A literature search was performed; the results and recommendations were discussed among the authors. Four authors considered a scenario. The final article was discussed and approved by the International Commission for Mountain Emergency Medicine (ICAR MEDCOM) in October 2013.

RESULTS AND RECOMMENDATIONS

Many health care providers fail to recognize, assess, and treat pain adequately. Assessment scales and treatment protocols should be implemented in mountain rescue services to encourage better management of pain. Specific training in assessing and managing pain is essential for all mountain rescuers. Persons administrating analgesics should receive appropriate detailed training. There is no ideal analgesic that will accomplish all that is expected in every situation. A range of drugs and delivery methods will be needed. Thus, an 'analgesic module' reflecting its users and the environment should be developed. The number of drugs carried should be reduced to a minimum by careful selection and, where possible, utilizing drugs with multiple delivery options. A strong opioid is recommended as the core drug for managing moderate or severe pain; a multimodal approach may provide additional benefits.

Wilderness Medical Society practice guidelines for the treatment of acute pain in remote environments

The Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for the management of pain in austere environments. Recommendations are graded based on the quality of supporting evidence as defined by criteria put forth by the American College of Chest Physicians.

Wilderness medicine

BACKGROUND

Human activity in wilderness areas has increased globally in recent decades, leading to increased risk of injury and illness. Wilderness medicine has developed in response to both need and interest.

METHODS

The field of wilderness medicine encompasses many areas of interest. Some focus on special circumstances (such as avalanches) while others have a broader scope (such as trauma care). Several core areas of key interest within wilderness medicine are discussed in this study.

RESULTS

Wilderness medicine is characterized by remote and improvised care of patients with routine or exotic illnesses or trauma, limited resources and manpower, and delayed evacuation to definitive care. Wilderness medicine is developing rapidly and draws from the breadth of medical and surgical subspecialties as well as the technical fields of mountaineering, climbing, and diving. Research, epidemiology, and evidence-based guidelines are evolving. A hallmark of this field is injury prevention and risk mitigation. The range of topics encompasses high-altitude cerebral edema, decompression sickness, snake envenomation, lightning injury, extremity trauma, and gastroenteritis. Several professional societies, academic fellowships, and training organizations offer education and resources for laypeople and health care professionals.

CONCLUSIONS

THE FUTURE OF WILDERNESS MEDICINE IS UNFOLDING ON MULTIPLE FRONTS: education, research, training, technology, communications, and environment. Although wilderness medicine research is technically difficult to perform, it is essential to deepening our understanding of the contribution of specific techniques in achieving improvements in clinical outcomes.

Ketamine in pain management

For ketamine's fiftieth birthday, a narrative review of this unique drug in pain management is presented. Its history is traced from its conception, and its heritage, as a phencyclidine offspring, delineated. The earliest roots of the conceptions concerning the mechanisms of action are sought, and then followed in preclinical as well as clinical research. The major proposed mechanisms in the literature are commented on and evaluated. The growth of the clinical evidence for perioperative pain, acute pain, and chronic pain is followed from early attempts to systematic reviews. Finally, an attempt is made to foresee what the next 50 years might hold in store for our 50 years old.

Prehospital advances in the management of severe penetrating trauma

BACKGROUND

Historic advances in combat prehospital care have been made in the last decade. Unlike other areas of critical care, most of these innovations are not the result of significant improvements in technology, but by conceptual changes in how care is delivered in a tactical setting. The new concept of Tactical Combat Casualty Care has revolutionized the management of combat casualties in the prehospital tactical setting.

DISCUSSION

The Tactical Combat Casualty Care concept recognizes the unique epidemiologic and tactical considerations of combat care and that simply extrapolating civilian care concepts to the battlefield are insufficient.

SUMMARY

This article examines the most recent and salient advances that have occurred in battlefield prehospital care driven by our ongoing combat experience in the Iraq and Afghanistan and the evolution around the Tactical Combat Casualty Care concept.

Venomous snakebite in mountainous terrain: prevention and management

The prevention and management of venomous snakebite in the world's mountains present unique challenges. This paper presents a series of practical, clinically sound recommendations for management of venomous snakebite in a mountain environment. The authors performed an extensive review of current literature using search engines and manual searches. They then fused the abundant knowledge of snakebite with the realities of remote first aid and mountain rescue to develop recommendations. A summary is provided of the world's most troublesome mountain snakes and the mechanisms of toxicity from their bites. Preventive measures are described. Expected symptoms and signs are reviewed in lay and medical terms. A review of currently recommended first-aid measures and advanced medical management for physicians, paramedics, and other clinicians is included. Venomous snakebites in mountainous environments present unique challenges for management. This paper offers practical recommendations for managing such cases and summarizes the approach to first aid and advanced management in 2 algorithms.

Earthquake injuries and the use of ketamine for surgical procedures: the Kashmir experience

The October 8, 2005 earthquake in Northern Pakistan had widespread destructive effects throughout the northern subcontinent. Large numbers of people were killed or severely injured and many medical services destroyed. This report describes the experience of the only standing surgical hospital in the Kashmir region of Bagh District. More than 1,500 people were triaged in 72 hours, many critically injured; 78.4% of patients had upper or lower limb injuries; 50.3% of patients had fractures, mainly closed; 37% of patients required extensive wound debridements. A total of 149 patients received emergency surgery using ketamine anaesthesia with benzodiazepine premedication. This was found to be safe, effective and with a low incidence of major adverse effects. We recommend that ketamine anaesthesia be encouraged in disaster area surgery, particularly in under-resourced regional centres.