Deep (3rd–4th degree): Hard/woody texture, complete anesthesia, hemorrhagic blisters, progression to dry gangrene/mummification.
Immediate Management (High-Yield Hierarchy):
Stabilize core first: Address systemic hypothermia before local injury.
Rapid active rewarming: Water bath at 37–39°C (98.6–102.2°F) for 15–30 min until tissue is pliable/erythematous. c
Aggressive analgesia: IV opioids + NSAIDs (reperfusion is excruciating).
Wound care: Elevate extremity, apply topical aloe vera, apply loose non-adherent sterile dressings (separate digits with gauze), administer tetanus prophylaxis.
Critical Board “Don’ts”:
Do not rewarm in the field if there is any risk of refreezing (refreezing massively amplifies tissue necrosis).
Do not rub or massage tissue (causes mechanical shear injury).
Do not use dry radiant heat/heating pads (high burn risk due to loss of sensation).
Subacute & Advanced Medical Care:
Clear blisters: Debride or aspirate (removes destructive thromboxanes).
Hemorrhagic blisters: Leave intact (prevents deep dermal desiccation and infection).
Thrombolysis: IV/IA tPA or prostacyclin (iloprost) if deep/severe ischemia presenting < 24 hours post-thaw.
Imaging: Tc-99m bone scan or CTA to evaluate microvascular flow and tissue viability.
Surgical Management:
Delay amputation: Wait 1–3 months (“amputate in July”) to allow definitive tissue demarcation between viable skin and necrotic eschar.
Early surgery indications: Emergent escharotomy/fasciotomy for reperfusion-induced compartment syndrome; immediate debridement for acute wet gangrene/sepsis.