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Chapter 4

Frostbite

Anne Wagner, MD and Rob Orman, MD
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35:01

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Managing frostbite is both simple and complex. It's been around since human skin met the cold but  research within the past few decades and even the past few years has dramatically changed how we care for  thermal cold injury. in this episode, frostbite expert and burn surgeon Dr. Anne Wagner discusses frostbite diagnosis, simple and advanced management.

 

Pearls:

  • Frostbite can cause damage through to the bone but on the surface may not look bad until 12 hours or more after rewarming.  

  • While a blister filled with serous fluid is characteristic of 2nd degree frostbite, hemorrhagic blisters occur in 3rd degree injuries.

  • Frostbitten tissue should be rapidly rewarmed in water. Once thawed, it is critical that the tissue not refreeze.

  • Aloe vera blocks harmful inflammatory mediators in blister fluid and can be applied to intact as well as unroofed blisters.

  • 3rd and 4th degree frostbite are emergent conditions warranting aggressive treatment. Intravenous thrombolytics should be considered if the patient presents to care within 24 hours of rewarming.

 

  • The guest today is Dr. Anne Wagner.  She is a trauma surgeon who is an expert in the management of burns, frostbite, and complex wounds.  Dr. Wagner runs the burn center at the University of Colorado Hospital.

 

  • What is the difference between frostnip,  frostbite, and burns?

    • Frostnip is a completely reversible injury manifested by pain and erythema after cold exposure which resolves within an hour.  

    • In frostbite, the tissue may initially be hard, white, insensate, and difficult to move.  With rewarming, the pain increases and the skin may take on a pale appearance.  Over time, the tissue may become red with areas of dark discoloration. Blistering may not develop for 2-7 days.

    • Unlike a burn which typically only affects the surface tissues, frostbite can cause damage through to the bone but may not look too bad until 12 hours or more after rewarming.  

    • Frostbite classification:

      • 1st degree -- Purplish tinge to the skin without blistering.  Can be painful. Heals completely without need for medical intervention other than padding for protection.

      • 2nd degree --Large, tense and painful blister filled with serous fluid. Pain relief with drainage of the blister.

      • 3rd degree -- Hemorrhagic blister.  Should be left alone and protected to avoid rupture.  

      • 4th degree -- Injury extends through skin into muscle, tendon and bone.  

  • Frostbite treatment

    • Protect the injured tissue to avoid ongoing damage from the ice crystals within the skin. Prehospital providers should apply a bulky dressing and take off cold or wet clothing. Anticipate swelling and remove anything that’s restraining, such as rings and socks.

    • Rapid rewarming

      • Do it once you know you can do it completely.

      • Use a vessel that can easily accommodate the affected area.

      • The best way to rewarm is with water, ideally 40 degree celsius temperature.  Frozen tissue can typically be thawed within 30 minutes.

      • You will need to add warm water to the bath to maintain the proper temperature.

    • Pain control

      • Those with 1st degree injuries may have pain for up to a week.  2nd degree injuries can be painful for a month and cold sensitive for a year.  Special precautions, such as extra warm socks and gloves, should be used until asymptomatic. Patients with 3rd and 4th degree injuries that are treated aggressively early on (ie. with thrombolytics)  may have pain for a shorter duration than those with 2nd degree frostbite.

      • Before rewarming, pain can be managed with high dose ibuprofen or ketorolac (Toradol) and gabapentin (300 mg).

        • In addition to analgesia, ibuprofen has been shown to block harmful inflammatory mediators which can cause vasoconstriction and deepening of the injury.  Wagner keeps patients on 800 mg tid as they’re healing.

        • NSAIDS are preferred over aspirin which blocks both the good and bad inflammatory mediators.

        • Heggers JP, et al. Experimental and clinical observations on frostbite. Ann Emerg Med. 1987 Sep;16(9):1056-62. PubMed PMID: 3631670

      • During rewarming, IV opiates (Wagner uses fentanyl), dexmedetomidine (Precedex), and/or ketamine may be necessary.  

    • Blister management and wound care

      • Keep the injured extremity elevated and wounds clean.  Apply 100% aloe vera to all frostbitten areas and cover with a gauze dressing/wrap.  Change this 3 times daily.

        • Aloe blocks thromboxane A2, a harmful inflammatory mediator in blister fluid. It can be irritating  to the skin, especially with open blisters. Adding a cream (such as Eucerin) can make it more tolerable.

        • Klein, Alan D., and Neal S. Penneys. "Aloe vera." Journal of the American Academy of Dermatology 18.4 (1988): 714-720.

      • Remove the serous or serosanguinous fluid from 2nd degree frostbite blisters by deroofing the blister and debriding the dead skin. This fluid is inflammatory and causes vasoconstriction. Then cover with aloe vera.

        • Robson MC, Heggers JP. Evaluation of hand frostbite blister fluid as a clue to pathogenesis. J Hand Surg Am. 1981 Jan;6(1):43-7. PubMed PMID: 7204918.

      • Leave hemorrhagic blisters alone due to the increased infection rate and risk of losing healthy skin if these are debrided.  Cover with aloe vera and protect from further harm with a dressing or splint. If on the foot, keep the patient non-weightbearing until the skin is mostly healed.

        • When a hemorrhagic blister ruptures on its own, sharply debride any loose skin and dress with aloe vera three times a day.

    • Avoid further cold exposure until after the tissue has completely recovered.  One of the worst things that can happen is to refreeze tissue recently thawed. Once someone has gone through a freeze, thaw, freeze cycle, the only treatment available for them is supportive care.

    • Removal of eschar shouldn’t be done too early as it may expose underlying tendon or bone.  A triple-phase bone scan can show how well a digit is perfusing and guide therapy.

    • Thrombolytics

      • Why does it work?  A large part of the injury with frostbite is endothelial damage and thrombosis.

      • Indications:  3rd or 4th degree frostbite, even if it just involves a small area.   Infusion within 24 hours of rewarming.

        • Multiple studies have shown decreased amputation rates with thrombolytics.

        • Some protocols have additional criteria for thrombolytics, such as absent doppler pulses in the limbs and/or digits and absence of perfusion on angiography or Technetium 99 triple-phase bone scanning.

      • Contraindications:  Greater than 24 hours since rewarming or anyone who’s gone through a freeze, thaw, freeze cycle.

        • The duration of time that tissue has been frozen is not an exclusion.  Wagner has had success with patients who have been frozen for over 2-3 days.

      • The earlier it’s given, the better, but start only after the patient has been rewarmed.  For every hour after rewarming that thrombolytics are withheld, there’s a 28% decrease in salvage rate.

      • Dosing regimen:  alteplase 0.15 mg/kg IV over 15 minutes, then 0.15 mg/kg/hr for 6 hours up to a maximum total dose of 100 mg.

      • Just prior to turning off the thrombolytic, Wagner starts patients on a 1 week course of treatment dose enoxaparin (1 mg/kg SQ).

      • Frostbite patients do best if cared for at a facility that’s accustomed to taking care of frostbite.  This ensures that the patient will get proper wound care, physical and occupational therapy, and advice regarding ambulation.  

      • Wagner prefers systemic/intravenous TPA to intra-arterial TPA because it treats the whole patient.  Most people with frostbite have multiple frozen extremities; the systemic route will treat any affected body part. Furthermore, systemic TPA is more readily available at most hospitals.

      • Twomey JA, et al. An open-label study to evaluate the safety and
        efficacy of tissue plasminogen activator in treatment of severe frostbite. J
        Trauma. 2005 Dec;59(6):1350-4; discussion 1354-5. PubMed PMID: 16394908.

      • Bruen KJ, et al. Reduction of the incidence of amputation in frostbite injury with thrombolytic therapy. Arch Surg. 2007 Jun;142(6):546-51; discussion 551-3. PubMed PMID: 17576891.

      • Gonzaga T, J et al. Use of Intra-arterial Thrombolytic Therapy for Acute Treatment of Frostbite in 62 Patients with Review of Thrombolytic Therapy in Frostbite. J Burn Care Res. 2016  Jul-Aug;37(4):e323-34. PMID: 25950290.

      • Nygaard RM, et al.  Time Matters in Severe Frostbite: Assessment of Limb/Digit Salvage on the Individual Patient Level. J Burn Care Res. 2017 Jan/Feb;38(1):53-59. PMID: 27606554.

    • Is there a role for hyperbaric oxygen (HBO) therapy?  It may help.  While original studies didn’t show benefit, recent case reports have shown success.

      • HBO decreases tissue edema, reverses inflammatory mediators, makes it easier for red blood cells to fit through vessels, and highly oxygenates the areas that are trying to heal.

      • The protocol involves treatment every day for 90 minutes, at least 5 days a week, at 2.4 atmospheres.

      • Finderle Z, Cankar K. Delayed treatment of frostbite injury with hyperbaric oxygen therapy: a case report. Aviat Space Environ Med. 2002 Apr;73(4):392-4. PubMed PMID: 11952063

      • von Heimburg D, et al. Hyperbaric oxygen treatment in deep frostbite of both hands in a boy. Burns. 2001 Jun;27(4):404-8. PubMed PMID: 11348755.

      • Kemper TC, et al. Frostbite of both first digits of the foot treated with delayed hyperbaric oxygen:a case report and review of literature. Undersea Hyperb Med. 2014 Jan-Feb;41(1):65-70. Review. PubMed PMID: 24649719.

gmete -

As an ER provider in Alaska I found this CME very helpful since I never really had much training on this. I really appreciate this lecture. It was great!

Rob O., MD -

Thanks for the positive feedback! When I first saw Dr. Wagner give her frostbite talk several years ago, my mouth was agape (figuratively) over the number of high yield pearls she dropped. Two that stand out to me were the importance of aloe vera and intravenous lytics instead of intra-arterial. Total game changers.

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