1. Frostbites • Chemical burns • Electrical injury • Commisure burns

2. Frostbites

3. Frostbites • Military injury in the past • “Trench foot” • “Tropical immersion foot" • Rise in homelessness • Rise in outdoor activities and sports

4. Frostbites - Epidemiology • Ages 30-49 • Male : Female 10 : 1 • Predisposing factors - • Alcohol consumption (46%) • Motor vehicle trauma (19%) or failure (15%) • Psychiatric illness (17%)

5. Frostbites - Epidemiology Other comorbidities: • Homelessness • Improper clothing • Atherosclerosis • Diabetes • Smoking • Wound infection

6. Cold Injury – Hypothermia • Can occur in any weather. • Mechanisms of heat loss : • Radiation (55-65%) • Evaporation • Respiration • Conduction and convection (3-15%) (20-30%)

8. Hypothermia - Treatment • Field – passive rewarming • Hospital – active rewarming • Surface rewarming • Warm IV fluids, peritoneal irrigation, warm air inhalation • CBC, PT/PTT, Chem7, ABG ,Tox. Screen • Arrhythmias

9. “No patient is dead until warm and dead.”

10. Frostbites – Where ? Most commonly affected sites Hands and feet (90%) Ears Nose Cheeks Penis

11. Frostbites - Pathophysiology • Tissue freezing • Hypoxia • Release of inflammatory mediators

12. Frostbites – PathophysiologyFreezing • Extracellular ice crystal formation. • Intracellular ice crystals. • Intracellular dehydration. • Denaturation of membrane lipid-protein complexes.

13. Frostbites – PathophysiologyHypoxia • “The hunting reaction” • Local vasoconstriction • Acidosis • Increased blood viscosity • Thrombosis

14. Frostbites – PathophysiologyInflammation • Release of PGF2 and TXA2 • Cycles of warming and freezing increase mediator release • Cell death • Exacerbation of dermal vasoconstriction, aggregation, thrombosis, hypoxia…

16. Frostbites Degree of irreversability is related to the length of time the tissue remains frozen more than to absolute temperature

17. I White plaque + erythema II Clear/milky fluid blisters III Hemorrhagic blisters IV Necrosis – non blanching cyanosis, wooden feeling Superficial Deep Frostbites – Clinical ManifestationsPost Rewarming !!!

18. Frostbite - Symptoms • Numbness  pain (48-72 h) tingling and electric currents (1wk- 6mo) • Sensory loss, increased cold sesitivity, hyperhydrosis • Rare – growth plate disturbences, osteoarthritis, chronic pain, heterotopic calcifications

19. Frostbites - Radiology • X-Ray • fragmantation, distraction, disappearence • Epiphyseal fusion • Arteriography • Early flow slowing • Residual occlusion after rewarming • Vasodilatior addition – better predictor

20. Frostbites - Radiology • Tc scan • Assess tissue viability • Allows earlier debridment • MRI/MRA • Visualization of occluded vessels • Demarcation line of ischamic soft tissue

21. Frostbite – TreatmentField Care • Rapid transport to care center • Warm only if refreezing can be prevented or hospital arrival > 2 hours • Splint, bulky and loose padding • DO NOT rub extremity • NO alcohol and smoking

22. Frostbite – TreatmentAcute Hospital Care • Admit to hospital • Warm water immersion 40–42ºc, 15-30 min • Debridment of clear blisters, aloe vera cream • Splint, elevation, loose dressing

23. Frostbite – TreatmentAcute Hospital Care • Ibuprofen 12 mg/kg/d, 400 mg q12h • IM dT • IV PCN 5x105 U q6h, for 72 hours • IV MO

24. Frostbite – TreatmentLong Term Hospital Care • Hydrotherapy, physiotherapy • Medical tx • Dextran, anticoagulation, vasodalation - not proven • Thrombolysis, delayed sympathectomy– promising • Compartment syndrome  escharotomy, fasciotomy • Infection control  limited debridment • Amputation only after 22-45 days

25. Frostbites – early treatment • Minimize expectant duration • Maximize tissue saved • 48 hrs triple-phase bone scan identifies areas of bony nonperfusion.

26. Frostbites – early treatment • Early debridmant of “high metabolizing” tissue • Transfer of vascularized tissue to supply “low metabolizing” tissues

27. Frostbite – early treatment