Cold and Heat Injuries-AUK.pptx heat and

Heat and cold

1. Cold and Heat Injuries

2. Content

3. TYPES OF COLD INJURIES TYPE Description Chilblains Caused by prolonged exposure of skin to non freezing temperatures Trench Foot Prolonged exposure to wet and cold conditions can cause constriction of blood vessels and can shut down circulation in feet Frost Bite Caused by freezing characterized by loss of sensation and color of the affected area. It can permanently damage the body tissues and severe cases can lead to self amputation

4. Chilblains Caused by prolonged exposure of skin to non freezing temperatures Common, prone to frost bite Hands and feet most affected R edness and itching Constriction of skin blood vessels, Edema in dermis Keep part dry and warm, Vaseline, Oral Nifedipine (20-60 mg/day) Resolve spontaneously in 1-3 weeks

5. Trench Foot Exposure to prolonged periods of wet but non freezing temperutures Immobilisation of lower extremities with constriction of limbs by shoes and clothing 1 Prehyperemic few hours to days cold swollen, discoloured , numb 2 Hyperemic 2-6 weeks bounding, pulsatile circulation in red swollen foot 3 Post Hyperemic weeks to months warm, increased sensitivity to cold, may show gangrene washing and air drying, gentle rewarming, bed rest Improvement in 24-48 h, injury resolution in 1-2 weeks

6. Frost bite A B

7. Frost bite Environmental temperature falls below the freezing point(about minus 4 o C or 25 o F) Irreversible tissue damage Prefreeze , Freeze thaw, vascular stasis, late ischaemic Grading: 1 degree: Loss of sensation, Hyperemia, edema 2 degree: Vesicles with clear fluid and surrounding edema 3 degree: Hemorrhagic vesicles with scar formation 4 degree: Necrotic tissue, auto amputation

8. Frost bite Hot fluids, sleeping bags, extra blankets Dry dressing, Ibuprofen, Pentoxyfiline Rewarming-water bath 39-42 o C- 30-45 min IV tissue plasminogen activator, heparin Treatment of blisters Bed rest 2 weeks

9. Hypothermia Core body temperature less than 35 o C (95 o F)

10. Hypothermia Multiple organ systems are affected Basal Metabolic Rate (BMR) decreases Chances of circulatory arrest, still one have an excellent chance of survival

11. Hypothermia Important questions to address Pulse/ Resp/ ECG Consciousness Shivering Mental Status Mild: 32.2-35 o C Moderate: 28-32.2 o C Severe: less than 28 o C

12. 36.8 ± 0.4 o C (98.2 ± 0.7 o F ) Normal body temperature Maintenance of Body Temperature

13. Factors Affecting Body Temperature 01 02 03 04 Infancy Old age AGE Diurnal variations Variation of 1 degree Highest: 1600-1800h Lowest: 0400-0600h Temperature can rise upto 38.3-40 degree Celsius Exercise Progesterone T3, T4 Epinephrine, Norepinephrine Hormones 05 Activation of Sympathetic system Stress / Anxiety Stress

14. SET POINT Shivering Increased Voluntary Activity Decreased Heat loss Cutaneous Vasoconstriction Curling up Horripilation Hunger Cutaneous vasodilation Sweating Panting Increased respiration Anorexia Apathy Temperature Regulation

15. Evaporation 1 g water – 0.58kCal heat lost Insensible loss- 600-700ml/day Sweat Acclimatization of sweating mechanism

16. Heat Related Disorders Heat Cramps Heat Edema (Deck Ankles or Colombo flop) Heat syncope Hidromeiosis Prickly Heat Heat exhaustion Heat stroke- Higher than 41 o C

17. Heat Cramps Painful, involuntary muscle spasms Heavy exercise Hot environment Stoppage of activity, rehydration and gentle stretching and transfer to health care facility

18. Heat exhaustion- salt depleted, water depleted Prolonged exposure to hot environment Weakness, Headache, ↑ Sweating Nausea & Vomiting Rest in a Cool place, cooling measures and symptomatic treatment

19. Heat stroke- Higher than 41 o C Failure of hypothalamic thermostat Core temperature> 105 Degree F Dizziness, abdominal distress Delirium, unconsciousness; Fatal Immediate treatment, cold water bath, active cooling.

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