Prevention and Treatment of Frostbite
MAINTAINING PERIPHERAL PERFUSION
PROTECTION FROM COLD
- avoiding environmental conditions that predispose to frostbite, specifically below -15°C, even with low wind speeds;
- protecting skin from moisture, wind, and cold;
- avoiding perspiration or wet extremities;
- increasing insulation and skin protection (eg, by adding clothing layers, changing from gloves to mitts);
- ensuring beneficial behavioral responses to changing environmental conditions (eg, not being under the influence of illicit drugs, alcohol, or extreme hypoxemia)
- using chemical hand and foot warmers and electric foot warmers to maintain peripheral warmth (note: warmers should be close to body temperature before being activated and must not be placed directly against skin or constrict flow if used within a boot);
- regularly checking oneself and the group for extremity numbness or pain and warming the digits and/or extremities as soon as possible if there is concern that frostbite may be developing;
- recognizing frostnip or superficial frostbite before it becomes more serious; and
- minimizing duration of cold exposure. Emollients do not protect against—and might even increase—risk of frostbite.
- The time that a digit or extremity can remain numb before developing frostbite is unknown; thus, digits or extremities with paresthesia should be warmed as soon as possible. An extremity at risk for frostbite (eg, numbness, poor dexterity, pale color) should be warmed with adjacent body heat from the patient or a companion, using the axilla or abdomen.
Field treatment and secondary prevention
SPONTANEOUS OR PASSIVE THAWING
- Scenario 1: The frozen part has the potential for refreezing and is not actively thawed.
- Scenario 2: The frozen part is thawed and kept warm without refreezing until evacuation is completed.
THERAPEUTIC OPTIONS FOR BOTH SCENARIOS
Treatment of hypothermia
Low molecular weight dextran
SPECIFIC RECOMMENDATIONS—SCENARIO 1
Ambulation and protection
Rapid field rewarming of frostbite
Spontaneous or passive thawing
Debridement of blisters
Topical aloe vera
Ambulation and protection
Elevation of extremity
Immediate medical therapy—hospital (or high-level field clinic)
TREATMENT OF HYPOTHERMIA
LOW MOLECULAR WEIGHT DEXTRAN
RAPID REWARMING OF FROZEN TISSUES
MANAGEMENT OF BLISTERS
TOPICAL ALOE VERA
Thrombolytic treatment should be undertaken in a facility familiar with the technique and with intensive care monitoring capabilities. If a frostbite patient is being cared for in a remote area, transfer to a facility with tPA administration and monitoring capabilities should be considered if tPA can be started within 24 h of tissue thawing. Time to thrombolysis appears to be very important, with best outcomes within 12 h and ideally as soon as possible. Recent work from Hennepin County has found that each hour of delay of thrombolytic therapy results in a 28% decrease in salvage. Rare use of tPA in the field has shown variable success and should only be undertaken with extreme caution because bleeding complications may be impossible to detect and treat. If other treatment options are limited or unavailable, tPA should be considered for field treatment only of severe frostbite extending to the proximal interphalangeal joint or more proximally (eg, Cauchy classification grade 3 to 5).
Method of administrationDosing is typically a 3 mg bolus (30 mL of 0.1 mg·mL-1 solution) followed by infusion of 1 mg·mL-1 (10 mL·h-1) until specialists (eg, vascular, burn, radiology) recommend discontinuation. Heparin is administered concurrently: 500 units·h-1.Intra-arterial angiography or IV pyrophosphate scanning should be used to evaluate the initial injury and monitor progress after tPA administration as directed by local protocol and resources. As of the end of 2018, the following have been published on tPA use in frostbite: 1 randomized controlled prospective trial (tPA plus iloprost, 16 patients), 3 retrospective cohort studies (59 patients), 8 retrospective case series (130 patients), and 3 case reports. Although further studies are needed to determine the absolute efficacy of tPA for frostbite injury and to compare intra-arterial tPA to IV prostacyclin, we recommend IV or intra-arterial tPA within 24 h of injury as a reasonable choice in an environment with appropriate monitoring capabilities.
If available, appropriate imaging should be used to assess tissue viability and guide timing and extent of amputation. (1 – Strong, C)
A randomized trial by Cauchy et al assessed the efficacy of aspirin plus: 1) buflomedil, an alpha-blocker vasodilator; 2) iloprost; or 3) intravenous tPA plus iloprost. Forty-seven patients with severe frostbite, with 407 digits at risk, were randomly assigned to 8 d of treatment with the 3 different regimens. Iloprost alone (0% amputation rate) was found superior to tPA plus iloprost (19%) and buflomedil (60%) groups. A limitation of this study was that ischemia was not documented with angiography or technetium scanning before treatment; groups were randomized according to clinical severity.
A Canadian study documented full recovery of grade 3 frostbite when iloprost was started within 48 h of injury in 2 long distance runners. In a Finnish study, iloprost was partially beneficial with digit salvage rate of 78% in 4 persons: 2 with contraindication for tPA, 1 with failed tPA therapy, and 1 with vasospasm without thrombosis on angiography. One patient with minimal response to tPA had complete reperfusion with iloprost.
Despite the limitations of these initial studies, iloprost has shown consistently favorable effects. Extending the treatment window, Pandey et al. reported good results with iloprost therapy up to 72 h after injury. In 5 Himalayan climbers with 34 digits at risk, 5 d of daily iloprost infusion produced excellent outcomes in 4 of 5 patients. Treatment delayed beyond 72 h has not been beneficial except in 1 patient. No serious side effects have been noted in these studies.
Intravenous iloprost should be considered first-line therapy for grade 3 and 4 frostbite <72 h after injury, when tPA is contraindicated, and in austere environments where tPA infusion is considered risky or evacuation to a treatment facility will be delayed. Field use of both iloprost and IV tPA has been advocated to reduce delay in treatment for mountaineers who will invariably take >48 h for evacuation to a hospital. In these situations, iloprost may be the safer alternative. The IV form of iloprost is not approved by the US Food and Drug Administration, however. Consider iloprost for deep frostbite to or proximal to the proximal interphalangeal joint; within 48 h after injury, especially if angiography is not available; or with contraindications to thrombolysis. Expedition physicians should consider adding iloprost to their medical armamentarium, especially if it can be safely sourced and when treatment is occurring outside of the United States. (1 – Strong, B)
Method of administrationIloprost dosage is given IV via controlled infusion or syringe pump. Iloprost is mixed with normal saline or dextrose in water. On days 1 through 3, start at an initial rate of 0.5 ng·kg-1·min-1, then gradually increase by 0.5 ng·kg-1·min-1 at 30-min intervals to a maximum dose of 2.0 ng·kg-1·min-1. If intolerable side effects (nausea, headache, flushing) emerge or blood pressure or heart rate are outside normal limits, reduce the rate by 0.5 ng·kg-1·min-1 until side effects are tolerable or vital signs normalize. Mild and tolerable side effects can be treated symptomatically, whereas hypotension or severe symptoms require dose reduction. Continue the highest dose achieved or a maximum of 2.0 ng·kg-1·min-1 for 6 h total. For days 4 through 5, start directly at the highest/optimum rate or a maximum of 2.0 ng·kg-1·min-1 for 6 h daily. Some protocols recommend up to 8 d of treatment; the first dose is considered the most important.
the 1 Israeli traveler with excellent outcome in the Kathmandu study, and 4 patients in the Finnish study were treated with low molecular weight heparin (enoxaparin) in addition to iloprost. Whether low molecular weight heparin offers additional benefit when combined with iloprost requires further investigation; currently data are insufficient for a recommendation on this combination. (, U)
OTHER VASODILATOR THERAPY
Other post-thaw medical therapy
HYPERBARIC OXYGEN THERAPY
SURGICAL TREATMENT OR AMPUTATION
Prevention and Treatment of Frostbite
July 1, 2019
Supplemental Implementation Tools
External Publication Status
Country of Publication
Female, Male, Adolescent, Adult, Child, Older adult
Health Care Settings
Ambulatory, Hospital, Medical transportation
Paramedic emt, athletics coaching, nurse, nurse practitioner, physician, physician assistant
Prevention, Management, Treatment
D007035 - Hypothermia, D005627 - Frostbite
rewarming, Frostbite, hypothermia, thrombolysis, iloprost