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.

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.

Wound care in the wilderness: is there evidence for honey?

Honey is one of the most ancient remedies for wound care. Current research has shown promising results for its use in wound care. This review is intended to inform readers of the physiological properties of honey and the evidence that exists to support its clinical use. When compared with evidence for current wound treatment, honey has proven to be a safe, effective, and sometimes superior treatment for various wounds. There are currently US Food and Drug Administration-approved medical-grade honey products available in the United States. Although there have been no clinical trials exploring the use of honey in wilderness environments, it may be a safe, improvisational wound treatment. More robust studies are needed for definitive conclusions of its efficacy and safety.

A blinded, randomized, palatability study comparing variations of 2 popular field water disinfection tablets.

OBJECTIVE: Halogen-based water disinfection tablets may render an unpleasant taste to treated water. Proposed safe additives such as ascorbic acid may reduce this objectionable taste. We compared the palatability of 2 field water disinfectants: iodine-based tetraglycine hydroperiodide (TGHP) and chlorine-based chlorine dioxide (CD) both with and without the concomitant use of an ascorbic acid taste neutralizer. METHODS: Blinded participants randomly sampled 5 different distilled water samples containing combinations of disinfectant tablets and ascorbic acid: 1) water; 2) water with TGHP; 3) water with CD; 4) water with TGHP plus ascorbic acid; and 5) water with CD plus ascorbic acid. Participants rated beverage taste via a 100 mm visual analogue scale (VAS) and ranked the samples from "most pleasant" to "least pleasant." RESULTS: Sixty participants evaluated the samples. On the VAS, water with TGHP tasted worst and water with CD tasted second worst. Water with TGHP plus ascorbic acid, water alone, and water with CD plus ascorbic acid measured similarly as significantly best tasting. Water with TGHP was ranked by 58% as "least pleasant" tasting, while water with TGHP and ascorbic acid was ranked by 40% as "most pleasant" tasting. CONCLUSIONS: Participants found halogen-based disinfected water significantly less palatable prior to the addition of ascorbic acid. Addition of ascorbic acid to treated water created a beverage of similar preference to distilled water. These results may increase compliance with the use of disinfecting tablets by increasing the palatability of drinking water made potable via addition of ascorbic acid to halogen-based chemical disinfection.

10% Povidone-iodine may be a practical field water disinfectant.

OBJECTIVE: A paucity of data exists regarding the use of iodophores such as povidone-iodine (PVI) to disinfect water. We sought to determine a practical minimal disinfecting concentration of 10% PVI over different contact times and temperatures when added to water inoculated with E. coli. METHODS: 1:100, 1:1,000, and 1:10,000 dilutions of 10% PVI were created. Escherichia coli was exposed to these dilutions for 5, 15, and 30 minutes at 10, 20, and 30°C. Bactericidal activity was neutralized with 0.5% sodium thiosulfate. Mean viable colony forming units (CFUs) was determined after triplicate plating on Luria-bertani agar and 24 hours of incubation at 37°C. Effective bactericidal activity was defined as a 5-log reduction. RESULTS: Of the 200,000 E. coli plated, no CFUs were observed after exposure to the 1:100 dilution. After 5 minutes of contact time with the 1:1,000 dilution, at 10°C CFUs were too numerous to count (TNTC), at 20°C the mean CFU count was 92 (standard error ±11), and at 30°C the mean CFU count was 25 (standard error ±8). No CFUs were observed after 15 minutes of exposure to the 1:1,000 dilution across experimental temperatures. The 1:10,000 dilution always yielded CFU growth that was TNTC. CONCLUSIONS: The lowest disinfecting concentration of 10% PVI was the 1:1,000 dilution at 15 minutes of contact time. This supports the use of PVI for water disinfection against E. coli, the organism most commonly responsible for traveler's diarrhea. Further studies may assess its effectiveness against more virulent water borne pathogens.

Pain management in the wilderness and operational setting.

The wilderness and operational setting places unique constraints on one's ability to treat pain. In this article we will discuss methods for treating pain both in the wilderness and operational setting. By operational we mean the austere deployed military setting, to include both noncombat and combat operations. The authors combined experience with wartime trauma pain management consists of experience in Operation "Just Cause" (Panama Invasion), Operation "Desert Storm" (Persian Gulf War), Operation "Uphold Democracy" (Haiti liberation), Operation "Enduring Freedom" (Afghanistan conflict), and Operation "Iraqi Freedom" (Iraq conflict).

Event medicine: injury and illness during an expedition-length adventure race.

To describe the incidence and type of injury and illness occurring during an expedition-length adventure race and identify those resulting in withdrawal from the event, a prospective cohort study was conducted of the injuries and illness treated during the Subaru Primal Quest Expedition Adventure Race trade mark held in Colorado July 7-16, 2002. All racers, support crewmembers, and race staff were eligible to participate in the study. When a member of the study group received medical care due to an injury or illness, the encounter was recorded on a Medical Encounter Form. If an injury or illness resulted in withdrawal from the race, this was also recorded. Information from the Medical Encounter Forms was used to generate the Medical Log. There were 671 individuals eligible to participate in the study. A total of 243 medical encounters and 302 distinct injuries and illnesses were recorded. There were 179 (59%) injuries and 123 (41%) illnesses. Skin and soft tissue injuries and illness were the most frequent (48%), with blisters on the feet representing the single most common (32.8%). Second was respiratory illness (18.2%), including upper respiratory infection, bronchitis and reactive airway disease-asthma. Respiratory illness was the most common medical reason for withdrawal from the event. Injuries accounted for almost 60% of all injury and illness yet they contributed to less than 15% of the medical withdrawals from the race. Blisters accounted for almost one-third of all conditions treated. Providers of medical support for expedition-length adventure races should be prepared to treat a wide variety of injury and illness.

Intubating laryngeal mask airway versus laryngoscopy and endotracheal intubation in the nuclear, biological, and chemical environment.

OBJECTIVE: Intubation is a difficult skill under normal circumstances and more so with a limited visual field such as wearing a protective mask in a chemical or biological incident. This study sought to determine whether successful intubation using the intubating laryngeal mask airway (ILMA) under protective mask conditions was equivalent to standard endotracheal intubation. METHODS: A pilot study was conducted using emergency medicine personnel. Participant's attempted intubation of a manikin while wearing a standard U.S. Army M-40 protective mask. Two attempts were performed with each method. RESULTS: One hundred percent of the ILMA placements were successful with only 78% success with endotracheal intubation (p = 0.1). Time to successful intubation and ventilation was significantly less for the ILMA versus endotracheal intubation (p = 0.005). CONCLUSION: This study suggests that under simulated chemical and biological conditions using an M-40 protective mask, intubation is accomplished faster and with more success with the ILMA.

Safety and efficacy of oral transmucosal fentanyl citrate for prehospital pain control on the battlefield.

BACKGROUND: Acute pain, resulting from trauma and other causes, is a common condition that imposes a need for prehospital analgesia on and off the battlefield. The narcotic most frequently used for prehospital analgesia on the battlefield during the past century has been morphine. Intramuscular morphine has a delayed onset of pain relief that is suboptimal and difficult to titrate. Although intravenously administered morphine can readily provide rapid and effective prehospital analgesia, oral transmucosal fentanyl citrate (OTFC) is a safe alternative that does not require intravenous access. This study evaluates the safety and efficacy of OTFC in the prehospital battlefield environment. METHODS: Data collected during combat deployments (Afghanistan and Iraq) from March 15, 2003, to March 31, 2010, were analyzed. Patients were US Army Special Operations Command casualties. Patients receiving OTFC for acute pain were evaluated. Pretreatment and posttreatment pain intensities were quantified by the verbal numeric rating scale (NRS) from 0 to 10. OTFC adverse effects and injuries treated were also evaluated. RESULTS: A total of 286 patients were administered OTFC, of whom 197 had NRS pain evaluations conducted before and approximately 15 minutes to 30 minutes following treatment. The difference between NRS pain scores at 0 minutes (NRS, 8.0 [1.4]) and 15 minutes to 30 minutes (NRS, 3.2 [2.1]) was significant (p < 0.001). Only 18.3% (36 of 197) of patients were also administered other types of analgesics. Nausea was the most common adverse effect as reported by 12.7% (25 of 197) of patients. The only major adverse effect occurred in the patient who received the largest opioid dose, 3,200-µg OTFC and 20-mg morphine. This patient exhibited hypoventilation and saturation of less than 90% requiring low-dose naloxone. CONCLUSION: OTFC is a rapid and noninvasive pain management strategy that provides safe and effective analgesia in the prehospital battlefield setting. OTFC has considerable implications for use in civilian prehospital and austere environments. LEVEL OF EVIDENCE: Therapeutic study, level IV.

Use of a novel abdominal aortic tourniquet to reduce or eliminate flow in the common femoral artery in human subjects.

BACKGROUND: Penetrating injuries of proximal femoral and iliac vessels are a common cause of death on the battlefield. Previous studies have shown that by applying 80 lb to 140 lb of pressure externally over the distal abdominal aorta, flow can be ceased in the common femoral artery (CFA). It has also been demonstrated that in a porcine model, an externally applied pneumatic abdominal aortic tourniquet (AAT) can occlude the aorta and inferior vena cava for 60 minutes without bowel injury or significant potassium elevations.The objectives of this study were (1) determine if AAT use in humans results in flow cessation in the CFA, (2) measure the pressure required to cease flow in the CFA, and (3) measure discomfort associated with application of the AAT. METHODS: Pulse wave Doppler measurements were taken in supine volunteers at the right CFA. The AAT was placed just above the iliac crests over the anterior abdomen. The AAT was inflated using a hand pump with an integrated manometer. Measurements were taken every 30 mm Hg. Discomfort was measured using a 10-point pain scale. RESULTS: In all subjects, flow was reduced in the CFA. Flow ceased in seven of nine subjects at a median pressure of 180 mm Hg (150-230 mm Hg). Median discomfort at ceasing of flow was 7 (3-10), returning to 0 after device removal. CONCLUSION: The AAT device was effective at reducing flow in the CFA and ceased flow in most of the subjects. Application of the device was associated with discomfort varying from moderate to severe and resolving with device removal.

Mass casualty triage: an evaluation of the science and refinement of a national guideline.

Mass casualty triage is the process of prioritizing multiple victims when resources are not sufficient to treat everyone immediately. No national guideline for mass casualty triage exists in the United States. The lack of a national guideline has resulted in variability in triage processes, tags, and nomenclature. This variability has the potential to inject confusion and miscommunication into the disaster incident, particularly when multiple jurisdictions are involved. The Model Uniform Core Criteria for Mass Casualty Triage were developed to be a national guideline for mass casualty triage to ensure interoperability and standardization when responding to a mass casualty incident. The Core Criteria consist of 4 categories: general considerations, global sorting, lifesaving interventions, and individual assessment of triage category. The criteria within each of these categories were developed by a workgroup of experts representing national stakeholder organizations who used the best available science and, when necessary, consensus opinion. This article describes how the Model Uniform Core Criteria for Mass Casualty Triage were developed.

Mass casualty triage: an evaluation of the data and development of a proposed national guideline.

Mass casualty triage is a critical skill. Although many systems exist to guide providers in making triage decisions, there is little scientific evidence available to demonstrate that any of the available systems have been validated. Furthermore, in the United States there is little consistency from one jurisdiction to the next in the application of mass casualty triage methodology. There are no nationally agreed upon categories or color designations. This review reports on a consensus committee process used to evaluate and compare commonly used triage systems, and to develop a proposed national mass casualty triage guideline. The proposed guideline, entitled SALT (sort, assess, life-saving interventions, treatment and/or transport) triage, was developed based on the best available science and consensus opinion. It incorporates aspects from all of the existing triage systems to create a single overarching guide for unifying the mass casualty triage process across the United States.

Pattern of injury and illness during expedition-length adventure races.

OBJECTIVE: To describe injuries and illnesses treated during an expedition-length adventure race and combine the results with those from previous studies to identify common patterns of injury and illness during these events. METHODS: The 2003 Subaru Primal Quest Expedition Length Adventure Race was held in Lake Tahoe, CA, from September 5 to 14, 2003. Eighty teams of 4 individuals participated. During the event, medical volunteers providing on-site medical care recorded each medical encounter on a medical encounter form. This information was used to describe the injuries and illnesses treated and was combined with previous investigations to identify common patterns of injury and illness during these events. RESULTS: During the 10-day study period, 356 patient encounters and 406 injuries and illnesses were recorded. The most frequent reason to require on-site medical care was injury of the skin and soft tissue (70.4%), with blisters the single most common of these injuries (45.6%). Other reasons were orthopedic injury (14.8%), respiratory illness (3.7%), and heat illness or dehydration (3.7%). CONCLUSIONS: The results of this and previous studies demonstrate a common pattern of injury and illness that includes a high frequency of skin and soft tissue injury, especially blisters. Injuries and illnesses such as altitude illness, contact dermatitis, and respiratory illness varied considerably among events. The number of patient encounters per athlete is similar among the studies, providing an approximation of the number of medical encounters expected given the number of participants. These results should assist medical providers for future events; however, it is imperative to carefully review the individual event to best predict the frequency of injury and illness.

To air is human: altitude illness during an expedition length adventure race.

OBJECTIVE: To calculate the incidence and prevalence of altitude illness (acute mountain sickness [AMS], high altitude pulmonary edema, and high altitude cerebral edema) during an expedition length adventure race and to determine factors contributing to its development as well as identify cases requiring medical treatment, withdrawal from the event, or both. METHODS: The Primal Quest Expedition Length Adventure Race was held in Colorado in July 2002. Sixty-two coed teams of four participated in the event. It began at an altitude of over 9500 feet, ascended to an altitude over 13,500 feet with a cumulative elevation gain of 69,400 feet, of which 40,000 feet occurred in the first 12 hours of the event. There was 138,800 total feet of altitude change during the event. All racers underwent a prerace medical assessment 24 hours before the start of the race and completed an Environmental Systems Questionnaire version 3-R (ESQ 3-R). Onsite medical staff provided treatment during the event. A standard medical encounter form was used to record all patient encounters including a presumed diagnosis and disposition. RESULTS: At the start of the race, the prevalence of altitude illness was 4.5%. The incidence of altitude illness requiring medical treatment during the race was 14.1% (AMS, 33 [13.3%]; high altitude pulmonary edema, 2 [.81%]) resulting in 4 (14.3%) of the 28 medical withdrawals from the race. There was no correlation between home altitude, prerace ESQ scores, and successful completion of the race. CONCLUSIONS: Altitude illness occurs among participants in expedition length adventure races and contributes significantly to withdrawal from the event.