Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

all patients

1st line – initial assessment and emergency care

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1st line – 

initial assessment and emergency care

Assess the patient for life-threatening injuries, hypothermia, and whether the patient is at risk of amputation. Life-threatening injuries, such as hypothermia or major trauma, take priority.[5]​ Fractures are managed conservatively until postwarming edema has resolved. If there is a risk of amputation, time is critical and transfer to a major trauma centre or vascular unit with access to modern treatments is urgent. The Canadian Frostbite Care Network Opens in new window

Early surgical intervention is only indicated to assist in wound debridement or to treat complications such as compartment syndrome and ischemia from a constricting eschar or subeschar infection.[1]

Oxygen should not be given routinely, but may be given if the patient is hypoxic.[4]

See Hypothermia, Compartment syndrome of extremities.

Plus – rapid rewarming

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Plus – 

rapid rewarming

Treatment recommended for ALL patients in selected patient group

Should be initiated as soon as possible, but not before the patient is safely protected from re-exposure to the cold.

Affected areas should be rapidly rewarmed in gently circulated warm water until rewarming is complete (usually 15 to 30 minutes).[4] The Wilderness Medical Society recommends that the water is warmed to 37°C to 39°C (98.6°F to 102.2°F), while The American Heart Association and American Red Cross Guidelines for First Aid recommend a higher upper limit of 40°C (104°F).[4][32]​ If a thermometer is not available, nonscalding water can be used, or water at a temperature that a non-frostbitten extremity can be comfortably submerged in for 45 minutes. Antibacterial soap or antiseptic solution can be added to protect against cellulitis, particularly if severe oedema is present. Warm wet packs can be used if a tub is not available.

Temperatures above 40°C (104°F) or dry heat can cause thermal injuries and should be avoided. Rubbing the affected tissue for rewarming should always be avoided.[33]

Jewellery should be removed from affected digits early because significant swelling can occur post-thaw and vascular compromise (tourniquet effect) may occur with tight rings.[4][14]​​ The affected extremity should be elevated above the level of the heart to avoid the development of dependent oedema.​[4]

Thawing is complete when the distal tip of the affected extremity flushes and skin becomes soft and pliable to the touch, signalling the end of vasoconstriction.[1][4][14][16][26][34]​​​[35][36][37][38][39][40]

Active movement of the affected extremity helps promote perfusion and should be encouraged early but patients should avoid walking on frostbitten extremities to avoid inadvertent injury.

Plus – non-steroidal anti-inflammatory drug (NSAID) ± additional analgesia

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all patients
Plus – 

non-steroidal anti-inflammatory drug (NSAID) ± additional analgesia

Treatment recommended for ALL patients in selected patient group

A non-steroidal anti-inflammatory drug (NSAID), such as ibuprofen, should be given for analgesia and to reduce inflammation. There is a theoretical benefit to blocking the arachidonic acid pathway that produces prostaglandins and thromboxanes which lead to vasoconstriction and further tissue damage. While no outcome studies have been reported, unless there are contraindications, ibuprofen can be commenced in the field and continued until the frostbite has healed or when surgery is needed.[4]

Alternatively, aspirin may be used if ibuprofen is not available. Aspirin blocks the production of certain prostaglandins that are beneficial to wound healing and may be counterproductive.[4] However, a therapeutic analgesic dose of aspirin may still be used if ibuprofen is not available, because its antiplatelet action is thought to be beneficial.[1]

An opioid (e.g., morphine) can be used for additional analgesia as required.[4]

Primary options

ibuprofen: 6 mg/kg orally twice daily initially (started in the field), increase dose according to response, maximum 2400 mg/day in 4 divided doses

Secondary options

aspirin: 325-650 mg orally every 4 hours when required, maximum 4000 mg/day

Tertiary options

morphine sulfate: 10-30 mg orally (immediate-release) every 4 hours when required initially, titrate dose according to response

Plus – wound care

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Plus – 

wound care

Treatment recommended for ALL patients in selected patient group

Although there is a paucity of evidence to support blister management, it is common practice to debride clear blisters in hospital, theoretically to prevent thromboxane-mediated tissue injury.[4] First aid providers should not debride blisters in the field.[32]​ Haemorrhagic blisters should be kept intact to avoid infection.[4]

Blisters should be treated topically with aloe vera cream or gel before dressing application and reapplied at each dressing change.[4] Aloe vera is believed to decrease prostaglandin and thromboxane formation.[4][15]

Padding with cotton or soft gauze should be used between digits to reduce tissue maceration, but circumferential dressings should be loose given the likelihood of the development of oedema.[4]

Affected parts should be kept elevated and loosely splinted.[4] Associated dislocations should be reduced as soon as thawing is complete, but fractures must be managed conservatively until oedema has resolved.

It usually takes 1 to 3 months to assess whether frostbitten and surrounding tissue is viable.[4]

Plus – tetanus prophylaxis

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all patients
Plus – 

tetanus prophylaxis

Treatment recommended for ALL patients in selected patient group

All patients require tetanus vaccination. Patients who have previously been immunised should receive a booster. Patients who have not been immunised should receive passive immunisation with tetanus immunoglobulin. Tetanus immunoglobulin should be administered at a different site from the tetanus vaccination, preferably in an uninjured extremity. See Tetanus.

Plus – hydrotherapy

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all patients
Plus – 

hydrotherapy

Treatment recommended for ALL patients in selected patient group

Daily hydrotherapy should be performed at 37°C to 39°C (98.6°F to 102.2°F) for 45 minutes in a tank with sodium chloride and calcium hypochlorite solution.[4]

For a large tank, filled with 285 gallons, 9.7 kg of sodium chloride and 95 mL of calcium hypochlorite solution should be used.

For a tank filled with 108 gallons of water, 3.7 kg of sodium chloride and 36 mL of calcium hypochlorite should be used.

For a tank filled with 72 gallons of water, 2.5 kg of sodium chloride, 71 g of potassium chloride and 24 mL of calcium hypochlorite should be used.

Surgical soap can be added instead of sodium chloride and calcium hypochlorite.

Consider – hydration

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all patients
Consider – 

hydration

Additional treatment recommended for SOME patients in selected patient group

Aggressive hydration is important on initial presentation. Warmed fluids (at least to 37°C [98.6°F] but preferably 40°C [104°F] to 42°C[107.6°F]) can be given either intravenously or orally, depending on the patient's condition.[14]​ If fluids are given intravenously in the field, they should be infused in small rapid boluses (e.g., 250 mL) to avoid cooling in the environment.[4]

Consider – antibiotic therapy

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all patients
Consider – 

antibiotic therapy

Additional treatment recommended for SOME patients in selected patient group

Antibiotics are generally recommended for more severe injuries (grade 3 and 4), if there is severe oedema after thawing, or if wounds appear infected.[4][14][43]​​​ If the damaged tissue appears infected, coverage should include Streptococcus species,Staphylococcus species, Pseudomonas species, and gram-negative bacteria.

Local antibiotic prescribing protocols should be consulted and antibiotics selected according to local sensitivity patterns and any patient antibiotics allergies considered.

When frostbite is severe, the risk of anaerobic infection is significant. This should be taken into consideration when choosing antibiotic regimens and making decisions regarding surgical intervention.[33]

Consider – rehabilitation

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Consider – 

rehabilitation

Additional treatment recommended for SOME patients in selected patient group

Early rehabilitation is essential for functional recovery and to prevent joint stiffness.[42]​ A high-protein, high-calorie diet helps promote healing.

Consider – iloprost or thrombolytic therapy

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all patients
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severe frostbite with risk of digit amputation (Grades 2 to 4)
Consider – 

iloprost or thrombolytic therapy

Additional treatment recommended for SOME patients in selected patient group

Patients should be transported to be treated in units familiar with the treatment of moderate to severe frostbite.

It is usually possible to determine if a patient is likely to require an amputation. The decision about who to treat with iloprost or recombinant tissue plasminogen activator (r-tPA), such as alteplase, is a judgement call for clinicians. In addition to the degree of severity, factors that influence the clinical decision include hand dominance, thumb injury, and the patient’s occupation (e.g., craftsman, musician, laborer). In the experience of the authors, units treating large numbers of patients with moderate to severe frostbite will have a better concept of the risk versus benefit of treating or not treating an individual patient, and which agent is most appropriate. Units with less experience, or who cannot access iloprost, might consider that the risk of r-tPA is only balanced by the benefit of treating more severe (Grade 3 to 4) frostbite.

Although it is more widely available, r-tPA is more complex to administer and has more adverse effects than iloprost. Both drugs are usually provided in a critical care or high-dependency setting with close monitoring of blood pressure and symptoms. Iloprost is given intravenously and r-tPA can be given intravenously or intra-arterially. r-tPA demonstrates better efficacy (and a higher complication rate) when given intra-arterially. It requires more intensive monitoring than iloprost and coagulation tests. In the opinion of the authors, there are no good indications for the use of r-tPA if iloprost is available.

Iloprost is a prostacyclin mimetic and a potent vasodilator that also reduces inflammation, and inhibits platelet aggregation.[4] It is approved in the US for the treatment of severe frostbite to reduce the risk of digit amputations, and has been used in Europe for many years (although it is not approved there for this indication).[44] Where there is a risk of amputation, iloprost can be given intravenously for deep frostbite extending to the distal interphalangeal joint or further (Grades 2 to 4). Despite a lack of strong evidence, iloprost is the first-line choice for Grades 3 to 4 frostbite.[4][44][45]​ Iloprost has a lower adverse effect and complication rate compared with r-tPA, so it may be considered as treatment for Grade 2 as well as more severe (Grades 3 and 4) frostbite. It should be given as soon as possible, but can be administered up to 72 hours after rewarming.[4] It is particularly helpful if angiography is not available or there are contraindications to thrombolysis.[14]​ The drug is typically given for approximately 6 hours a day for a total of 5 to 8 days in cases of grade 3 or 4 frostbite.[Figure caption and citation for the preceding image starts]: Typical frostbite injuries in the hands and feet of a climber with mildly haemorrhagic bullae presenting 3 days after exposure. The bullae were aseptically aspirated and a 5-day iloporost infusion resulted in a complete recoveryHallam M-J, BMJ 2010;341:c5864 [Citation ends].com.bmj.content.model.Caption@1b2960c4

r-tPA is more widely available than iloprost. Only deep injuries with likely amputations (e.g., extending into the proximal interphalangeal joints of digits, Grades 3 to 4) should be considered for thrombolytic therapy.[4] r-tPA may be considered within 24 hours after thawing with appropriate angiographic intervention for deep frostbite at the distal interphalangeal joint or more proximal to this.[4] Time to thrombolysis appears to be critical.[4] Contraindications to r-tPA include trauma, recent surgery and recent stroke. Heparin is used in r-tPA protocols, but there is no evidence to support the use of heparin alone for treating frostbite either in the field or in hospital.[4]

Primary options

iloprost: 0.5 nanograms/kg/minute intravenous infusion initially, titrate in 0.5 nanograms/kg/minute increments at 30 minute intervals according to response, maximum 2 nanograms/kg/minute; administer as continuous infusion for 6 hours each day up to a maximum of 8 consecutive days

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Secondary options

alteplase: consult specialist for guidance on dose

Consider – surgery

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necrotic tissue, signs of sepsis, or compartment syndrome
Consider – 

surgery

Additional treatment recommended for SOME patients in selected patient group

Early surgical intervention is only indicated to assist in the debridement of ulcers and necrotic tissue, or if the patient presents with signs of sepsis.[41]​ See Sepsis in adults. 

Fasciotomy is required to treat compartment syndrome that may be induced by oedema associated with thawing.[4] See Compartment syndrome of extremities.

Early amputation is rarely required. Most injuries will heal or mummify without surgery, so amputation should be delayed for as long as possible. It is also recommended that surgery be delayed until 6 to 12 weeks post-injury because surgical trauma can interfere with wound healing in the proximal tissue and thereby increase tissue loss. This also allows a sufficient period of time for demarcation of the wounds to help guide surgical procedures (skin graft, flap, or amputation).[16][42]​ Risk factors for amputation include late presentation, lower extremity involvement, and infection of the injured tissue.

Skin grafting can be considered in selected severely injured patients.[46][Figure caption and citation for the preceding image starts]: A typical frostbite affecting the hallux and third left toes showing the initial injury at presentation at base camp on Everest (A), at 6 weeks (B), and at 10 weeks (C). Note the delayed surgical amputation of the hallux after definitive demarcation and the recovery of the third digit after appropriate managementHallam M-J, BMJ 2010;341:c5864 [Citation ends].com.bmj.content.model.Caption@3d215557

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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