1. Frostbites Chemical burns Electrical injury Commisure burns

2. Frostbites

3. 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. Other comorbidities: –Homelessness –Improper clothing –Atherosclerosis –Diabetes –Smoking –Wound infection Frostbites - Epidemiology

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 – Pathophysiology Freezing Extracellular ice crystal formation. Intracellular ice crystals. Intracellular dehydration. Denaturation of membrane lipid- protein complexes.

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

14. Release of PGF 2 and TXA 2 Cycles of warming and freezing increase mediator release Cell death Exacerbation of dermal vasoconstriction, aggregation, thrombosis, hypoxia… Frostbites – Pathophysiology Inflammation

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

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

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

21. Frostbite – Treatment Field 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 – Treatment Acute 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. Ibuprofen 12 mg/kg/d, 400 mg q12h IM dT IV PCN 5x10 5 U q6h, for 72 hours IV MO Frostbite – Treatment Acute Hospital Care

24. 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 Frostbite – Treatment Long Term Hospital Care

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

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

27. Frostbite – early treatment