Wilderness Medical Society Clinical Practice Guidelines for the Prevention and Treatment of Heat Illness: 2024 Update.

The Wilderness Medical Society (WMS) convened an expert panel in 2011 to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. The current panel retained 5 original members and welcomed 2 new members, all of whom collaborated remotely to provide an updated review of the classifications, pathophysiology, evidence-based guidelines for planning and preventive measures, and recommendations for field- and hospital-based therapeutic management of heat illness. These recommendations are graded based on the quality of supporting evidence and the balance between the benefits and risks or burdens for each modality. This is an updated version of the WMS clinical practice guidelines for the prevention and treatment of heat illness published in Wilderness & Environmental Medicine. 2019;30(4):S33-S46.

Day of Ascent Dosing of Acetazolamide for Prevention of Acute Mountain Sickness.

Background: Acetazolamide is the most common medication used for prevention of acute mountain sickness (AMS), usually administered the day or night before ascent. The objective of this study was to evaluate the efficacy of day of ascent dosing of acetazolamide for AMS prevention. Methods: Double-blind, randomized, controlled noninferiority trial of acetazolamide 125 mg twice daily beginning either the night before or the morning of ascent. Healthy low altitude adults ascended from 1240 m (4100 ft) to 3810 m (12,570 ft) during summer 2018 on White Mountain, California. Primary outcome was incidence of AMS with the two different dosing patterns, assessed by the 1993 Lake Louise Questionnaire (LLQ) of ≥3 with headache and a minimum of 1 for other symptom. Results: One hundred four participants completed the study, with 54 (52%) randomized to night before acetazolamide and 50 (48%) to day of ascent dosing, without differences in baseline characteristics. There was 9% greater incidence of AMS in the day of ascent acetazolamide group (48.0% vs. 39%, 95% confidence interval [CI] -11.8 to 30, p = 0.46, number needed to treat [NNT] = 5.6 vs. 3.7), with the CI just surpassing the predetermined 26% noninferiority margin. There was a lower incidence of severe AMS (1993 LLQ >5) in the day of ascent group (n = 5, 10%, NNT = 2.3) compared with night before dosing (n = 12, 22%, NNT = 3.1) (95% CI -28 to 3.6), and lower average symptom severity in the day of ascent group (3 vs. 3.5, 95% CI -0.5 to 1.4). Conclusions: Day of ascent acetazolamide demonstrated higher rates of AMS compared with traditional dosing by a small margin. With similar rates of severe AMS and overall symptom severity, the potential for improved convenience and compliance may support day of ascent use.

Ibuprofen versus placebo effect on acute kidney injury in ultramarathons: a randomised controlled trial.

BACKGROUND: Despite concerns that non-steroidal anti-inflammatory drugs (NSAIDs) contribute to acute kidney injury (AKI), up to 75% of ultramarathon runners ingest these during competition. The effect of NSAID on AKI incidence in ultramarathon runners is unclear. METHODS: Multisite randomised double-blind placebo-controlled trial in the Gobi, Atacama, Ecuador and Sri Lankan deserts to determine whether ibuprofen (400 mg every 4 hours) would be non-inferior to placebo during a 50-mile (80 km) foot race. The primary outcome was incidence of AKI defined as severity categories of 'risk' of injury of 1.5× baseline creatinine (Cr) or 'injury' as 2× Cr, combined to calculate total incidence at the finish line. Non-inferiority margin for difference in AKI rates was defined as 15%. RESULTS: Eighty-nine participants (47% ibuprofen and 53% placebo) were enrolled with similar demographics between groups. The overall incidence of AKI was 44%. Intent-to-treat analysis found 22 (52%) ibuprofen versus 16 (34%) placebo users developed AKI (18% difference, 95% CI -4% to 41%; OR 2.1, 95% CI 0.9 to 5.1) with a number needed to harm of 5.5. Greater severity of AKI was seen with ibuprofen compared with placebo (risk=38% vs 26%; 95% CI -9% to 34%; injury=14% vs 9%; 95% CI -10% to 21%). Slower finishers were less likely to encounter AKI (OR 0.67, 95% CI 0.47 to 0.98) and greater weight loss (-1.3%) increased AKI (OR 1.24, 95% CI 1.00 to 1.63). CONCLUSION: There were increased rates of AKI in those who took ibuprofen, and although not statistically inferior to placebo by a small margin, there was a number needed to harm of 5.5 people to cause 1 case of AKI. Consideration should therefore be taken before ingesting NSAID during endurance running as it could exacerbate renal injury. TRIAL REGISTRATION NUMBER: NCT02272725.

Wilderness Medical Society practice guidelines for the prevention and treatment of heat-related illness: 2014 update.

The Wilderness Medical Society (WMS) convened an expert panel to develop a set of evidence-based guidelines for the recognition, prevention, and treatment of heat illness. We present a review of the classifications, pathophysiology, and evidence-based guidelines for planning and preventive measures as well as best practice recommendations for both field and hospital-based therapeutic management of heat illness. These recommendations are graded on the basis of the quality of supporting evidence, and balance between the benefits and risks or burdens for each modality. This is an updated version of the original WMS Practice Guidelines for the Prevention and Treatment of Heat-Related Illness published in Wilderness & Environmental Medicine 2013;24(4):351-361.