Prevention and Treatment of Nonfreezing Cold Injuries and Warm Water Immersion Tissue Injuries: Supplement to Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Frostbite.

We convened an expert panel to develop evidence-based guidelines for the evaluation, treatment, and prevention of nonfreezing cold injuries (NFCIs; trench foot and immersion foot) and warm water immersion injuries (warm water immersion foot and tropical immersion foot) in prehospital and hospital settings. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according to the criteria published by the American College of Chest Physicians. Treatment is more difficult with NFCIs than with warm water immersion injuries. In contrast to warm water immersion injuries that usually resolve without sequelae, NFCIs may cause prolonged debilitating symptoms, including neuropathic pain and cold sensitivity.

Novel application of chemical cold packs for treatment of exercise-induced hyperthermia: a randomized controlled trial.

OBJECTIVE: Heat-related illness is a common disease with significant morbidity and mortality. Despite no proven efficacy, application of chemical cold packs (CCP) to the skin overlying the large vessels of the neck, groin, and axillae is a traditional recommended cooling modality. The study objective was to compare the cooling rates of CCP applied to these traditional areas vs the glabrous skin surfaces of the cheeks, palms, and soles in exercise-induced hyperthermia. METHODS: Ten healthy adult male volunteers walked on a treadmill in a heated room (40°±0.5°C) while wearing insulated military overgarments until their esophageal temperatures (Tes) reached 39.2°C. Each participant had three heat stress trials on separate days: no treatment followed by randomly ordered traditional (neck, groin, and axillae) cooling and glabrous skin cooling. RESULTS: With no treatment, Tes remained stable after the first 5 minutes of the heat trial (ΔTes=0.12°±0.07°C/10 min). Traditional cooling followed a linear decline (ΔTes=0.17°±0.04°C/10 min; P<.001). Glabrous cooling enhanced the treatment effect by a steeper decline (ΔTes=0.30°±0.06°C/10 min; P<.001), significantly different from traditional cooling by 2-way analysis of variance (P<.001). CONCLUSIONS: Application of CCP to glabrous skin surfaces was more effective for treating exercise-induced heat stress than the traditional CCP cooling intervention. This novel cooling technique may be beneficial as an adjunctive treatment for heat-related illness in the prehospital environment.

Wilderness Medical Society practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia.

To provide guidance to clinicians, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations.

Wilderness Medical Society practice guidelines for the out-of-hospital evaluation and treatment of accidental hypothermia: 2014 update.

To provide guidance to clinicians, the Wilderness Medical Society (WMS) convened an expert panel to develop evidence-based guidelines for the out-of-hospital evaluation and treatment of victims of accidental hypothermia. The guidelines present the main diagnostic and therapeutic modalities and provide recommendations for the management of hypothermic patients. The panel graded the recommendations based on the quality of supporting evidence and the balance between benefits and risks/burdens according the criteria published by the American College of Chest Physicians. The guidelines also provide suggested general approaches to the evaluation and treatment of accidental hypothermia that incorporate specific recommendations. This is an updated version of the original Wilderness Medical Society Practice Guidelines for the Out-of-Hospital Evaluation and Treatment of Accidental Hypothermia published in Wilderness & Environmental Medicine 2014;25(4):425-445.

Core content for wilderness medicine fellowship training of emergency medicine graduates.

Wilderness medicine is the practice of resource-limited medicine under austere conditions. In 2003, the first wilderness medicine fellowship was established, and as of March 2013, a total of 12 wilderness medicine fellowships exist. In 2009 the American College of Emergency Physicians Wilderness Medicine Section created a Fellowship Subcommittee and Taskforce to bring together fellowship directors, associate directors, and other interested stakeholders to research and develop a standardized curriculum and core content for emergency medicine (EM)-based wilderness medicine fellowships. This paper describes the process and results of what became a 4-year project to articulate a standardized curriculum for wilderness medicine fellowships. The final product specifies the minimum core content that should be covered during a 1-year wilderness medicine fellowship. It also describes the structure, length, site, and program requirements for a wilderness medicine fellowship.

D-dimer is not elevated in asymptomatic high altitude climbers after descent to 5340 m: the Mount Everest Deep Venous Thrombosis Study (Ev-DVT).

We performed this study to determine the prevalence of elevated D-dimer, a marker for deep venous thrombosis (DVT), in asymptomatic high altitude climbers. On-site personnel enrolled a convenience sample of climbers at Mt. Everest Base Camp (Nepal), elevation 5340 m (17,500 ft), during a single spring climbing season. Subjects were enrolled after descent to base camp from higher elevation. The subjects completed a questionnaire to evaluate their risk factors for DVT. We then performed a D-dimer test in asymptomatic individuals. If the D-dimer test was negative, DVT was considered ruled out. Ultrasound was available to perform lower-extremity compression ultrasounds to evaluate for DVT in case the D-dimer was positive. We enrolled 76 high altitude climbers. None had a positive D-dimer test. The absence of positive D-dimer tests suggests a low prevalence of DVT in asymptomatic high altitude climbers.

Prospective, double-blind, randomized, placebo-controlled comparison of acetazolamide versus ibuprofen for prophylaxis against high altitude headache: the Headache Evaluation at Altitude Trial (HEAT).

OBJECTIVE: High altitude headache (HAH) is the most common neurological complaint at altitude and the defining component of acute mountain sickness (AMS). However, there is a paucity of literature concerning its prevention. Toward this end, we initiated a prospective, double-blind, randomized, placebo-controlled trial in the Nepal Himalaya designed to compare the effectiveness of ibuprofen and acetazolamide for the prevention of HAH. METHODS: Three hundred forty-three healthy western trekkers were recruited at altitudes of 4280 m and 4358 m and assigned to receive ibuprofen 600 mg, acetazolamide 85 mg, or placebo 3 times daily before continued ascent to 4928 m. Outcome measures included headache incidence and severity, AMS incidence and severity on the Lake Louise AMS Questionnaire (LLQ), and visual analog scale (VAS). RESULTS: Two hundred sixty-five of 343 subjects completed the trial. HAH incidence was similar when treated with acetazolamide (27.1%) or ibuprofen (27.5%; P = .95), and both agents were significantly more effective than placebo (45.3%; P = .01). AMS incidence was similar when treated with acetazolamide (18.8%) or ibuprofen (13.7%; P = .34), and both agents were significantly more effective than placebo (28.6%; P = .03). In fully compliant participants, moderate or severe headache incidence was similar when treated with acetazolamide (3.8%) or ibuprofen (4.7%; P = .79), and both agents were significantly more effective than placebo (13.5%; P = .03). CONCLUSIONS: Ibuprofen and acetazolamide were similarly effective in preventing HAH. Ibuprofen was similar to acetazolamide in preventing symptoms of AMS, an interesting finding that implies a potentially new approach to prevention of cerebral forms of acute altitude illness.

Drive-through medicine: a novel proposal for rapid evaluation of patients during an influenza pandemic.

STUDY OBJECTIVE: During a pandemic, emergency departments (EDs) may be overwhelmed by an increase in patient visits and will foster an environment in which cross-infection can occur. We developed and tested a novel drive-through model to rapidly evaluate patients while they remain in or adjacent to their vehicles. The patient's automobile would provide a social distancing strategy to mitigate the person-to-person spread of infectious diseases. METHODS: We conducted a full-scale exercise to test the feasibility of a drive-through influenza clinic and measure throughput times of simulated patients and carbon monoxide levels of staff. We also assessed the disposition decisions of the physicians who participated in the exercise. Charts of 38 patients with influenza-like illness who were treated in the Stanford Hospital ED during the initial H1N1 outbreak in April 2009 were used to create 38 patient scenarios for the drive-through influenza clinic. RESULTS: The total median length of stay was 26 minutes. During the exercise, physicians were able to identify those patients who were admitted and discharged during the real ED visit with 100% accuracy (95% confidence interval 91% to 100%). There were no significant increases of carboxyhemoglobin in participants tested. CONCLUSION: The drive-through model is a feasible alternative to a traditional walk-in ED or clinic and is associated with rapid throughput times. It provides a social distancing strategy, using the patient's vehicle as an isolation compartment to mitigate person-to-person spread of infectious diseases.

Acetazolamide fails to decrease pulmonary artery pressure at high altitude in partially acclimatized humans.

In this randomized, double-blind placebo controlled trial our objectives were to determine if acetazolamide is capable of preventing high altitude pulmonary edema (HAPE) in trekkers traveling between 4250 m (Pheriche)\4350 m (Dingboche) and 5000 m (Lobuje) in Nepal; to determine if acetazolamide decreases pulmonary artery systolic pressures (PASP) at high altitude; and to determine if there is an association with PASP and signs and symptoms of HAPE. Participants received either acetazolamide 250 mg PO BID or placebo at Pheriche\Dingboche and were reassessed in Lobuje. The Lake Louise Consensus Criteria were used for the diagnosis of HAPE, and cardiac ultrasonography was used to measure the velocity of tricuspid regurgitation and estimate PASP. Complete measurements were performed on 339 of the 364 subjects (164 in the placebo group, 175 in the acetazolamide group). No cases of HAPE were observed in either study group nor were differences in the signs and symptoms of HAPE found between the two groups. Mean PASP values did not differ significantly between the acetazolamide and placebo groups (31.3 and 32.6 mmHg, respectively). An increasing number of signs and symptoms of HAPE was associated with elevated PASP (p < 0.01). The efficacy of acetazolamide against acute mountain sickness, however, was significant with a 21.9% incidence in the placebo group compared to 10.2 % in the acetazolamide group (p < 0.01). Given the lack of cases of HAPE in either group, we can draw no conclusions about the efficacy of acetazolamide in preventing HAPE, but the absence of effect on PASP suggests that any effect may be minor possibly owing to partial acclimatization during the trek up to 4200 m.