Field Study on Intravenous Iloprost for Treatment of Severe Frostbite at High Altitude

This is a research project looking into the feasibility of frostbite treatment with iloprost in remote high altitude locations. This is an observational study. Rationale Frostbite is a significant risk for climbers and trekkers at high altitude, often resulting in long- term disability. Iloprost, a prostacyclin analogue, has shown promise in reducing amputation rates when administered intravenously within 72 hours of frostbite injury. Treatment delays are frequent due to the remoteness of climbing / trekking sites and limited access to medical facilities capable of administering iloprost. Each hour of treatment delay correlates with decreased digit salvage rates. Helicopter evacuations, commonly required to access such facilities, are often impossible or delayed due to harsh weather conditions, potentially compromising patient outcomes. We hypothesize that treatment for frostbites grade 3 \& 4 with iloprost is feasible and safe in pre-hospital, high-altitude settings and can contribute to ensuring treatment initiation within the recommended time frame. We anticipate a comparable incidence and severity of side effects to iloprost treatments facilitated in clinical settings. Our primary objective is to systematically evaluate the feasibility and safety of iloprost treatment under high-altitude field conditions. This assessment will encompass the analysis of logistical challenges and the practicality of iloprost use in remote and extreme environments. Outline This prospective field study aims to assess the feasibility and safety of iloprost administration for severe frostbite at high-altitude at Everest Basecamp, Nepal (5364m). The research will be conducted during the peak climbing seasons of 2026 and 2027, targeting adult patients (aged 18 and older) presenting with frostbite grades 3 or 4 according to the Cauchy visual grading scale. Method After obtaining written informed consent, patients will receive intravenous iloprost according to current clinical guidelines, ideally within 72 hours after thawing. Throughout the study practical challenges of administering advanced medical therapy in remote, resource-limited environments will be documented. Adverse effects associated with iloprost monitored for and treated as required. Data will be collected on participant demographics, injury characteristics, time to rewarming, time to treatment, drug administration details, and side effects, as well as short-term clinical outcomes such as tissue preservation and functional status upon discharge / further referral for treatment continuation in Kathmandu. If fewer than ten eligible cases are recruited in the first two years, the study will extend for an additional season to achieve its objectives. Whenever possible, follow-up assessments will be conducted to evaluate longer-term recovery and need for amputation. Outcomes will be compared with historical data from similar high-altitude environments to estimate the potential benefit of on-site iloprost treatment. Discussion By systematically evaluating the feasibility and safety of field-based iloprost administration for frostbite, this study seeks to generate actionable evidence for improving emergency care protocols in remote and extreme environments. The findings have the potential to reduce morbidity and healthcare costs associated with frostbite, inform future wilderness medicine guidelines, and improve outcomes for climbers and high-altitude workers worldwide.

• Baseline tissue at risk for amputation (Hennepin Frostbite Score at-risk component) [Time frame: From enrolment to 1 week after treatment initiation]
• Overall digital salvage rate at 6 and 12 months (Hennepin Frostbite Score-defined digits at risk vs amputated) after treatment completion [Time frame: From enrolment to 18 months after treatment completion]
• Number of participants undergoing any frostbite-related amputation by 6 months and by 12 months after end of treatment (clinical charts/operative notes & self reported) [Time frame: from enrollment to follow ups up to 18 months after discharge.]
• Number of joints salvaged per participant at 6 and 12 months (Hennepin Frostbite Score-based joint tissue at risk vs amputated) [Time frame: From enrolment to 18 months after discharge]
• Change from baseline in pain at follow-up (measured by Numeric Rating Scale (NRS) 0-10) [Time frame: from enrolment to 18months after treatment completion]
• Change from baseline in upper-extremity function at 6 and 12 months (QuickDASH, self-reported) [Time frame: From enrolment to 18months after treatment completion]
• Change from baseline in foot/ankle function at 6 and 12 months (FAAM-ADL, self-reported) [Time frame: From enrolment to 18 months after treatment completion]