effects of extreme cold

Effects of Cold

Characteristics of cold region Low humidity in Ladakh region High Humidity in Sikkim, Kashmir &

Arunanchal Pradesh Temp may go below -20 degree C to -40

degree C Less vegetation Wind Chill factor (at -1 degree C with

wind velocity at 50 Kmph effective temp becomes minus 10 degree C

Summer – Avalanches (Glaciers) Sun (UV Radiation) - Snow blindness

WIND-CHILL FACTOR

The felt air temperature on exposed skin due to wind

The combination of ambient low temperature and wind movement is termed the 'wind-chill' factor

The power of the climate to cause cold injuries is directly proportionate to the 'wind-chill' factor rather than its temperature alone

WIND-CHILL FACTOR

At altitude of < 2000 mtrs

Summer Slush Cold Winds But less severe because of

Protection by coniferous forests Temp low up to -10 degree C Rivers take shape here/originate Chillblains

BODY CORE - Heart- Heart - Brain- Brain - Lungs - Lungs - Liver- Liver - Kidneys- KidneysEXTREMITIES - Legs & feet- Legs & feet - Arms & hands- Arms & hands

Normal Normal core core body body

temperatemperature:ture:

98.6°F98.6°F

Adverse effects of Cold

Generalized – Hypothermia Localized

NON-FREEZING - Chillblain - Trench foot

FREEZING - Frostnip - Frostbite Others

Solar Keratitis (Snow blindness) Sunburns Rhinitis

HYPOTHERMIA

Elderly & ill Accidental In patrols/ treks, night duty Drug Addicts & Alcoholic (loss of heat & poor

decision making) Acute illness (disruption of thermoregulation) Premature neonate Diseases Hypothyroidism, Pitutary insuff,

addisons disease, Hypoglycemia, MI, Cirrhosis, Pancreatitis etc.

Outcome Acuteness and duration of exposure

HYPOTHERMIA

CORE BODY TEMP 35oC OR 95oF

MILD : 32 - 35 0C MODERATE : 32 - 28 0C SEVERE : 280C

CLINICAL FEATURES

Effects32 to 350C – Mental processes are slowed, Shivering

becomes violent, Paradoxical undressingless than320C – Ability to shiver lost, Deep tendon reflexes lost 280C – Coma supervenes, severe bradycardia 180C – EEG flat

CVS Effect Initially CO, HR & BP Then HR (Sinus bradycardia) (2-3 beats per min) ECG – Osborne wave (J wave) 280C - 300C – Susceptibility to refractory VF & Asystole

MILD HYPOTHERMIA

Shivering is intense & uncontrolled (sympathetic stimulation)

Rise in BP (peripheral V/C & increased CO)

Still alert & able to help himself Feels pain & discomfort Movements less coordinated Lethargy & later mild confusion Reversible

MODERATE HYPOTHERMIA

Shivering slows or stops Shivering is replaced by marked muscular

rigidity, and stiff distal movements Mental confusion & apathy Glassy stare slurred speech Blood pressure not detectable with arm

sphygmomanometer Breathing shallow and irregular Cardiac rhythm irregularities appear with

tachycardia, supra-ventricular arrhythmias, ventricular extra-systoles and T wave inversion in ECG

SEVERE HYPOTHERMIA

Deep coma and rigidity develop ECG may show classic J wave or Osborne

wave notching at end of QRS complex Pulmonary edema can occur Ventricular fibrillation resistant to cardio-

version May appear dead (in metabolic icebox) Lethal temperature can be highly

variable, and survival has been recorded at deep body temperature as low as 20`C

TREATMENT

PASSIVE EXTERNAL REWARMING Prevent heat loss (check rectal temp) Remove wet clothing Dry blankets Protection from wind Mattress – Ground sheet, blankets, poly sheets

Maint of airway, Oxygenation

Principle:Quick warming of the core without causing Simultaneous V/D of the periphery

TREATMENT

ACTIVE EXTERNAL REWARMING Apply warm packs at axillae, groin and

neck ‘Insulatory wrap’ (4 inches) Give warm sweetened tea, coffee or milk DON’T WARM EXTREMITIES (Arms by the

side) ‘AFTER DROP’ DON’T massage the limbs No physical activity No alcohol & tobacco

INTERNAL/CORE REWARMING 5 % IV Dextrose warmed upto 37- 41 degree

C 500ml to 1 ltr in half to one hr Oxygen inhalation by face mask Catheterise, monitor urine output Monitoring rectal temp (thermometer

inserted at least 15 cm into rectum) CPR if no carotid pulse Peritoneal / hemo-dialysis fluid at 37 – 41

degree C

Declare DEAD only after re-warming to 36 degree C of core temp

DICTUM : “A patient of hypothermia, in finality, is

never “Cold and Dead” but is “WARM AND DEAD”

Local Cold Injuries

COMMONLY AFFECTED AREAS

FingersFingers ToesToes Ear lobesEar lobes NoseNose CheeksCheeks Chin Chin Soles, heelSoles, heel Dorsal surface of Dorsal surface of

foot foot Male genitaliaMale genitalia ButtocksButtocks

CHILLBLAINS

- Nonfreezing cold injury - Cold, wet conditions (high humidity) - Repeated, prolonged exposure of bare skin - Can develop in only a few hours - Ears, nose, cheeks, fingers, and toes

CHILLBLAINS

SYMPTOMS: Initially pale and colorless worsens to achy, prickly sensation

then numbness red, swollen, hot, itchy, tender skin

upon rewarming Blistering in severe cases

TRENCH FOOT

Potentially crippling, nonfreezing injury

Prolonged exposure of skin to moisture (12 or more hours, days)

High risk during wet weather, in wet areas, or sweat accumulated in boots or gloves

TRENCH FOOT

TRENCH FOOT

SYMPTOMS: Initially appears wet, soggy, white,

shriveled Sensations of pins and needles, tingling,

numbness and then pain Skin discoloration - red, bluish, or black Becomes cold, swollen and waxy

appearance May develop blisters, open weeping or

bleeding

FROSTNIP

Mildest form of a freezing cold injury Generally reversible, no tissue injury or

permanent damage

Skin turns white, top layer of skin feels hard but deeper tissue still feels normal (soft)

May feel tingling or numbness

FROSTBITE Exposure to below

freezing temperatures

Can occur in above freezing temperatures due to wind chill factors and wetness

Contact with extremely cold objects (especially metal)

Contact with cooled or compressed gases, at normal temperatures (e.g., liquid nitrogen)

CLINICAL CLASSIFICATIONFIRST DEGREE - Erythema - Edema - Itching - No blisters/necrosis - Recovers

completely

CLINICAL CLASSIFICATION

SECOND DEGREE - Vesicles with clear

or milky fluid - Edema

CLINICAL CLASSIFICATION

THIRD DEGREE - Skin Necrosis - Blue grey

discolouration - Presence of blood

filled blisters

CLINICAL CLASSIFICATION

FOURTH DEGREE - Minimal oedema - Initially mottled, deep

red/cyanotic - Full thickness damage

affecting muscles, tendons & bones

- Later stages mummified

- Auto amputation

Frostbite Face

TREATMENT & PREVENTION

TREATMENT

PRE-HOSPITAL - Prevent further cold injury - Prevent mechanical trauma - Avoid rubbing - Restore general body warmth - Analgesics - Tetanus toxoid

TREATMENT

• Re-warming- 37 – 410 c for about 30 mins/ till flushed- Danger of burn injury- Avoid freeze-thaw-freeze cycle- Analgesics/sedatives

• Sterile loose dressings• Prophylactic antibiotics

TREATMENT

SURGERY- Excision- Escharotomy, - Skin graft- Amputation- Reconstruction procedures

TREATMENT

DRUG THERAPY - Vasodilators (ketanserin, buflomedil) - Pentoxifylline - Platelet aggregation inhibitiors (Aspirin) - Heparin - Hyperbaric oxygen

PRIMARY PREVENTION

Health promotion - Hygiene - Nutrition - Exercise - Avoid Smoking

Specific protection - Shelter - Clothing, boots & socks - Foot hygiene - Avoid Venous congestion - Aloe Vera

SECONDARY PREVENTION Early Diagnosis First Aid Prompt treatment

PREVENTION …contd Buddy system Cold adaptation Rapid evacuation Limit tissue injury Avoid re-exposure

DO’S & DON’T’S

DO’S - Remove tight shoes, socks etc. - Warm the injured parts (Not by direct heat) - Cover the body with blankets - Provide hot drinks and rest - Cover blisters with dry dressing - Treat as a stretcher patients

DON’T’S - Don’t massage or rub the parts - Don’t smoke or drink

DISCUSSION