Altitude, Field Physician Care, Frostbite
Conditions
Keywords
iloprost
Brief summary
The goal of this observational study is to learn whether intravenous iloprost treatment for severe frostbite (grades 3-4) is feasible and safe when delivered in pre-hospital, remote high-altitude settings. The main questions it aims to answer are: * Is it feasible to initiate and deliver guideline-based intravenous iloprost for grade 3-4 frostbite at high altitude and what logistical barriers arise? * Does field-based initiation of iloprost increase tissue preservation and reduce amputations (compared to historical cases from similar settings)? Participants receiving Iloprost as part of a frostbite treatment will be followed up after discharge as well as 6, 12 and 18 months to assess tissue preservation and long-term sequelae from the initial frostbite injury.
Detailed description
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.
Interventions
Begin Iloprost intravenous infusion as soon as feasible for all Grade 2-4 frostbite cases (optimally within 24-72 hours of injury, but it can be beneficial even if started later). Iloprost is a prostacyclin analogue vasodilator that improves blood flow and inhibits platelet aggregation, thereby counteracting frostbite's ischemic and thrombotic components. Key points for Iloprost administration: * Dosage and preparation: Iloprost is supplied in ampoules of 50mcg/0.5mL. Dilute 50 mcg into a 250mL bag of D5W (5% dextrose) to create a 0.2 mcg/mL solution. Iloprost infusion should be administered via a dedicated IV line using an infusion pump. * Infusion protocol: Start iloprost infusion at 10 mL/hour (which delivers 2 mcg/hour, assuming the 0.2 mcg/mL dilution). Every 30 minutes, increase infusion rate by 10 mL/hour, as tolerated, until the maximum rate appropriate for the patient's weight is reached (40-50 kg: up to 30 mL/hour; 51-74 kg: up to 40 mL/hour; ≥75 kg: up to 50 mL/hour.
Sponsors
Institute of Mountain Emergency Medicine
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Frostbite grade 3/4 eligible for Iloprost * \<72h of thawing * min. age of 18 years * provision of written informed consent
Exclusion criteria
* age \<18 years * general contraindication * pregnancy * inability/denial to provide informed consent
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Proportion of frostbite presentations with severe frostbite (Grade 3-4) at Everest ER | from enrolment to the end of treatment at 1 week | Patients will be assessed using Cauchy classification. Proportion of patients presenting with grade 3 + 4 frostbite in relation to the total number of patients with frostbite presenting at Everest ER Unit/format: proportion (%) |
| Proportion of eligible severe frostbite patients who complete ≥1 field iloprost treatment round | From enrolment to 1 week after beginning of treatment | The proportion of the number of patients who successfully completed at least one round of iloprost treatment under field conditions in relation to the number of eligible patients. Denominator explicitly: eligible grade 3-4 patients (Cauchy classification) Unit/format: proportion (%) |
| Time from thawing to initiation of iloprost treatment under field conditions | From enrolment to the end of treatment at day 1 | Unit/format: time (hours or minutes) |
| Proportion of iloprost-treated patients with mild adverse effects during/after ≥1 treatment round in the field setting | From enrollment to the end of treatment at 1 week | Unit/format: proportion (%) Adverse effects will be graded using CTCAE (CTCAE = Common Terminology Criteria for Adverse Events) severity criteria. Proportion of mild adverse effects in the field setting will then be compared with in-hospital settings. |
| Proportion of iloprost-treated patients with severe adverse effects during/after ≥1 treatment round in the field | From enrolment to the end of treatment at 1 week | Unit/format: proportion (%) Adverse effects will be graded using CTCAE (Common Terminology Criteria for Adverse Events) severity criteria. In a second step proportion of severe adverse events during field treatment will be compared with proportions of in-hospital treatment |
| Proportion of patients discontinuing field iloprost treatment (overall) and documented reasons for discontinuation | From enrolment to end of treatment at 1 week | Proportion of discontinued field treatments in relation to all initiated field treatments. Unit/format: proportion (%) + categorical reason counts |
| Proportion of iloprost treatment discontinuations attributable to adverse effects in the field | From enrolment to end of treatment at 1 week | Unit/format: proportion (%) Number of treatments discontinued due to adverse reactions in relation to all treatments discontinued (both in the field) |
| Qualitative description of logistical constraints and solutions from field notes and staff reports | From enrolment to end of treatment at 1 week | Notes and reports will be analysed using a thematic analysis approach to categorise logistical challenges. Reported as: themes/categories with illustrative summaries (qualitative) |
| Frequency of logistical challenges during field iloprost implementation | from enrolment to end of treatment at 1 week | Number of logistical challenges, classified using a logistical challenge themes arising from qualitative analysis of field notes and staff reports. Possible themes expected include challenges related to equipment availability or functionality, personnel issues, environmental barriers. Reported as: counts (n) and percentages (%) (number of challenges within one respective category in relation to all registered logistical challenges) |
| Proportion of logistical challenges resolved during the study period | from enrolment to end of treatment at week 1 | Number of logistical challenges resolved in relation to all challenges recorded within one defined logistical challenge theme. Reported as: percentage (%) The logistical challenges themes will be arising from qualitative analysis of field notes and staff reports. |
| Mean (SD) time from thawing to first iloprost administration (clinical charts/notes), stratified by logistical challenge status (none vs occurred), resolution status (resolved vs unresolved), and challenge category | From enrolment to end of treatment at 1 week | Time-to-treatment in the field will be calculated as the elapsed time between the documented thawing time and the documented start time of the first iloprost administration, as recorded in clinical charts/notes. Each case will be classified by logistical challenge status (no challenge vs challenge occurred). For cases with a challenge, resolution status will be recorded as resolved during the study period vs unresolved/persisting, and challenges will also be assigned to a logistical challenge category. Time-to-treatment will be summarized as mean (SD) within each stratum (e.g., none vs resolved vs unresolved, and by category) and compared across strata. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Baseline tissue at risk for amputation (Hennepin Frostbite Score at-risk component) | From enrolment to 1 week after treatment initiation | Baseline tissue at risk will be quantified using the Hennepin Frostbite Score at-risk component, documented at initial assessment (before 1st treatment administration). Results will be summarised as score values (mean \[SD\]). |
| Overall digital salvage rate at 6 and 12 months (Hennepin Frostbite Score-defined digits at risk vs amputated) after treatment completion | From enrolment to 18 months after treatment completion | At 6 and 12 months, the digital salvage rate will be calculated as the proportion of digits at risk that are not amputated, where "digits at risk" and "amputated" are determined using the Hennepin Frostbite Score methodology and follow-up documentation. Results will be reported as n/N and % with 95% confidence intervals, and may be compared with prespecified historical proportions from the literature (one-sample proportion testing as applicable). |
| 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) | from enrollment to follow ups up to 18 months after discharge. | Amputation status (any vs none) will be ascertained from clinical charts, operative notes and self reports at six and twelve months after treatment completion. Results will be reported as n (%) with 95% confidence intervals, and may be compared with pre-specified historical rates from the literature if feasible. |
| Number of joints salvaged per participant at 6 and 12 months (Hennepin Frostbite Score-based joint tissue at risk vs amputated) | From enrolment to 18 months after discharge | At 6 and 12 months after treatment completion, the number of joints salvaged per participant will be determined from the Hennepin Frostbite Score tissue-at-risk mapping and documented final tissue loss/amputation level. Results will be summarized per participant (e.g., mean \[SD\] and/or distributional summaries) at each timepoint. |
| Change from baseline in pain at follow-up (measured by Numeric Rating Scale (NRS) 0-10) | from enrolment to 18months after treatment completion | Pain intensity will be recorded using the Numeric Rating Scale (NRS) 0-10 as documented in clinical charts/notes at baseline (initial clinical assessment) and self reported at 6 months and 12 months follow-up. The outcome will be change from baseline in NRS score at each follow-up timepoint (follow-up minus baseline). Results will be summarised as mean (SD) at 6 and 12 months (and mean (SD) change), with within-person comparisons over time analysed using paired t-tests. |
| Change from baseline in upper-extremity function at 6 and 12 months (QuickDASH, self-reported) | From enrolment to 18months after treatment completion | Upper-extremity function will be assessed using the QuickDASH (11-item self-reported questionnaire about Disabilities of the Arm, Shoulder and Hand (DASH)) at baseline, 6 months, and 12 months. The outcome will be change from baseline in QuickDASH score at each follow-up timepoint (follow-up minus baseline). Results will be summarised as mean (SD) at 6 and 12 months (and mean (SD) change), with within-person comparisons over time analysed using paired t-tests (or pre-specified nonparametric alternatives if assumptions are not met). This assessment will only be undertaken in patients whit frostbites on the upper extremity. |
| Change from baseline in foot/ankle function at 6 and 12 months (FAAM-ADL, self-reported) | From enrolment to 18 months after treatment completion | Foot/ankle function will be assessed using the Foot and Ankle Ability Measure (FAAM) - Activities of Daily Living (ADL) subscale, a self-reported questionnaire, at baseline, 6 months, and 12 months. The outcome will be change from baseline in FAAM-ADL score at each follow-up timepoint. Results will be summarised as mean (SD) at 6 and 12 months (and mean (SD) change), with within-person comparisons analysed using paired t-tests (or pre-specified nonparametric alternatives if assumptions are not met). This assessment will only be undertaken in patients with frostbites affecting the lower extremities. |
Countries
Italy
Contacts
CONTACTLea AJ Duempelmann
Outcome results
None listed