What is the appropriate emergency department management for a patient presenting with frostbite, including assessment, rewarming, analgesia, tetanus prophylaxis, and treatment of superficial versus deep injuries?

Emergency Department Management of Frostbite

Rapidly rewarm all frostbitten tissue in warm water at 37-40°C (98.6-104°F) for 20-30 minutes, administer ibuprofen immediately for anti-inflammatory and anti-thrombotic effects, and consider thrombolytic therapy within 24 hours for severe injuries with perfusion deficits. 1, 2

Initial Assessment and Stabilization

Priority Determination

• If the patient has moderate to severe hypothermia, rewarm the core FIRST before treating frostbite, as rewarming extremities first can cause core temperature to drop further 1, 2
• Remove all jewelry, rings, watches, and tight clothing immediately from affected extremities to prevent constriction as swelling develops 1, 2
• Protect frostbitten tissue from mechanical trauma—do not allow the patient to walk on frozen feet or use frozen hands for any activity, as frozen tissue cannot sense ongoing damage 1, 2

Clinical Examination

• Assess for the "6 P's" of acute ischemia: Pain, Pallor/Purple discoloration, Pulselessness, Paresthesias, Paralysis, and Poikilothermia 3
• Check pedal pulses bilaterally—absent pulses suggest arterial insufficiency requiring urgent vascular consultation 3
• Classify injury severity: superficial frostbite (outer skin layers, no permanent tissue loss) versus deep frostbite (deeper tissues, potential for tissue necrosis and amputation) 4, 5
• Note that estimating severity is challenging initially, and tissue that appears severely damaged may recover better than expected 1, 2

Rewarming Protocol

Technique

• Immerse the affected extremity in warm water at 37-40°C (98.6-104°F) for 20-30 minutes 1, 2
• If no thermometer is available, test water against your wrist—it should feel slightly warmer than body temperature 1, 2
• Never use water above 40°C as this causes additional tissue damage 2, 5
• Air rewarming can be used as an alternative when warm water immersion is not possible 1, 2
• A continuous-temperature circulating water bath system maintains consistent temperature without requiring constant monitoring 6

Critical Rewarming Principles

• Do not rewarm if there is ANY risk of refreezing, as freeze-thaw-refreeze cycles cause exponentially worse tissue damage 1, 2, 4
• Rewarming causes hyperemia and is often extremely painful—prepare for aggressive analgesia 4
• The tissue will become numb during freezing but painful during rewarming 2, 4

Pharmacologic Management

Immediate Therapy

• Administer ibuprofen 400-600mg every 6-8 hours immediately to decrease prostaglandin and thromboxane production that causes vasoconstriction, dermal ischemia, and further tissue damage 1, 2, 7
• Provide aggressive analgesia for rewarming pain—opioids are often necessary 4
• Ensure tetanus prophylaxis is up to date 2

Advanced Therapy for Severe Injuries

• Consider tissue plasminogen activator (tPA) within 24 hours for severe frostbite with perfusion deficits, as this may decrease amputation rates 4, 8, 9
• Mean time to tPA should be under 120 minutes from ED arrival when indicated 8
• Fluorescence microangiography (FMA) can identify perfusion deficits at bedside and expedite decision-making for thrombolytic therapy 8
• Iloprost (prostacyclin therapy) is very promising for severe cases 4, 9

Post-Rewarming Wound Care

Dressing Application

• Apply bulky, clean, dry gauze or sterile cotton dressings to affected areas 2, 7
• Place dressing material between all digits (fingers and toes) to prevent maceration and pressure injury 2
• Wrap circumferentially but loosely to allow for swelling without constricting blood flow 1, 2
• The bulky dressings protect vulnerable tissue from trauma, absorb moisture, reduce infection risk, and distribute pressure evenly 1

Blister Management

• Do not debride blisters in the ED—leave intact blisters alone as intact skin is an essential barrier against infection 1, 2
• Hard eschar may form with healthy tissue deep to it—do not debride until clear demarcation from viable tissue develops, typically 1-3 months 4, 5
• Immediate escharotomy or fasciotomy is necessary only when circulation is compromised by compartment syndrome 5

Disposition and Follow-Up

Safe Discharge Criteria

• Discharge is safe if: no evidence of tissue ischemia on examination, tissue has been properly rewarmed, no risk of refreezing exists, and the patient can protect affected areas from further trauma 2
• Deep frostbite may require specialized care at a burn center 1, 2

Outpatient Management

• Arrange prompt podiatry or hand surgery follow-up within 24-48 hours for moderate injuries, sooner if any concern 2
• Continue ibuprofen long-term to prevent ongoing prostaglandin-mediated vasoconstriction 7
• Instruct patients to return immediately for: increasing pain, numbness, color changes, development of blisters, signs of infection, or any tissue breakdown 2

Critical Pitfalls to Avoid

• Never rewarm in the field if the patient will be transported to a facility within a reasonable time, as partial rewarming followed by refreezing is catastrophic 1, 2, 4
• Do not use chemical warmers directly on frostbitten tissue as they can reach temperatures causing burns 2
• Do not assume absence of pain means absence of injury in patients with diabetes or peripheral neuropathy—their impaired sensation masks injury 2
• Frozen and thawed tissues are extremely vulnerable to refreezing and infection—aggressive protection is mandatory 1, 2
• Previously frostbitten tissue has permanently altered thermoregulation and remains at high risk for recurrent injury with future cold exposure 3