The government of Pakistan on Tuesday 23rd of June, 2015, declared a state of emergency in Karachi, after an unprecedented heat wave killed about 800 people. The death toll has risen well beyond a thousand since then. Many more are left in life-threatening conditions. The death toll which was expected to rise is further exacerbated by lack of electricity, inadequate water and poor health care system.
In a similar event in India, over 2,500 people have died due to heat wave as at June. The 2015 Indian heat wave is said to be the 5th deadliest in the world and the 2nd deadliest in the history of India. The 2003 European heat wave that killed more than 70,000 people is the deadliest in history, next to that is the 2010 Russian heat wave that killed 56,000 people.
There are different definitions for heat wave, but generally in simple terms, heat wave occurs in a period of abnormally hot weather, usually humid and highly uncomfortable. Heat wave induces heat stresses including heat exhaustion and heat stroke, which can be fatal. It also worsens chronic cardiovascular and respiratory diseases.
Extreme weather events, including heat wave are expected more frequently in coming years, due to climate change. According to World Health Organization (WHO) projection, between 2030 and 2050, climate change is expected to cause approximately 250,000 additional deaths per year, from malnutrition, malaria, diarrhoea and heat stress.
Different regions of the world are prone to different natural events, hence, the need to be prepared.
Passers-by help a heatstroke victim in a market area of Karachi on June 23, 2015. Image credit: AFP Photo / Rizwan Tabassum (afp.com)

HEAT AND COLD INJURIES

Heat or cold injuries due to environmental conditions are conditions resulting from body’s temperature changes owing to the inability of the body to relatively adapt to the temperature changes of the surrounding. Continuous exposure to heat (such as heat wave) can induce heat-related conditions including heat stroke, heat exhaustion, heat syncope, heat cramp and heat rash.

TEMPERATURE CLASSIFICATION

There are different classifications for body temperature range. Body temperature depends on a number of factors including the individual’s state of health, age, time of the day, activities being done at the time of reading the temperature.
Normal: 36.5 – 37.5 °C (97.7 – 99.5 °F)
Hypothermia: < 35.0 °C (95.0 °F)
Fever: > 37.5 – 38.3 °C (99.5 – 100.9 °F)
Hyperthermia: > 37.5 – 38.3 °C (99.5 – 100.9 °F)
Hyperpyrexia: > 40.0°C (104°F)
The difference between fever and hyperthermia is the mechanism. Fever occurs with a corresponding increase in the hypothalamic set point, while hyperthermia occurs without a corresponding increase in the hypothalamic set point (temperature setting of the hypothalamus). All fevers are high temperature but not all high temperature conditions are fevers. Hyperthermia may also occur due to the effects of certain drugs of disease conditions; however, the focus here is on complications as a result of environmental conditions of heat wave.
Difference between hyperthermia, hypothermia and fever. Image credit: wikipedia.com

HEAT WAVE SAFETY

  • Monitor local weather situation for updates. A weather forecast may help. Crosscheck latest weather information with the heat index.
  • Avoid outdoor activities as much as possible. When indoors, maintain appropriate room air condition. Regulated mechanical equipment such as fans and air conditioners can be used.
  • If going out is unavoidable, wear only light-weighted, coloured and loose clothing. Dark coloured clothes absorb heat. A wide-brimmed hat can protect your face and head from heat. Using an umbrella and wearing sun glasses offers additional protection for the eyes.
  • If air conditioners are unavailable, stay on the ground floor.
  • If job tasks such as construction work are necessary, ensure they are carried out in teams and are adequately supervised. Take frequent breaks in a cool shelter.
  • Materials under the sun get heated up quickly; have a touch on them before using. Hot materials, especially metallic, can burn.
  • Monitor children and the elderly. They are prone to heat related illnesses.
  • Cars get heated up well in hot weather; don’t stay in them for too long if in heavy traffic except if appropriately air-conditioned; don’t leave children and the elderly alone in such situations. Pay more attention to cars with tinted windows as they tend to retain more heat with their windows wound up.
  • Avoid dehydration. Drink plenty of water or non-alcoholic drinks even when not thirsty. Do not drink alcoholic beverage. Consult your physician before increasing your fluid consumption if you are on a fluid restrictive diet.
  • Eat less food. More proteins equal more body heat production due to increased metabolism.
  • In addition to the above, know the signs and symptoms of heat related emergencies, their prevention and their management.
Heat index. Image credit: www.eurometeo.com

HEAT EXHAUSTION

This is a response of the body to continuous exposure to high environmental temperature, characterised by fatigue and collapse; it usually develops gradually after the loss of water and salt from the body through extensive sweating. Heat exhaustion can progress to heat stroke.
The casualty may experience cramps, known as heat cramp, due to the loss of water and salt from the body.
SIGNS AND SYMPTOMS OF HEAT EXHAUSTION         
  • Profuse perspiration
  • Fever
  • Moist and clammy skin
  • Pale or flushed skin
  • Headache
  • Dizziness and anxiety
  • Fatigue
  • Nausea, vomiting and diarrhoea
  • Rapid, but weak pulse
  • Fast and shallow breathing
  • Weakness
  • Muscular cramps
  • Impaired consciousness
FIRST AID FOR HEAT EXHAUSTION
  1. Remove the casualty to a cool place and make them rest.
  2. Lay the casualty down on the back, raise and support the legs, so as to improve blood supply to the brain.
  3. Remove excess clothing and sponge casualty with cold water.
  4. Give the casualty plenty of water, if possible, a weak salt solution of one teaspoon of salt per litre of water. You may also give sports drinks. Do not give tea, coffee, fizzy drinks or alcohol.
  5. Treat associated cramps.
  6. Place the casualty in recovery position, if his level of response deteriorates.
  7. Monitor the casualty and prepare to resuscitate.
  8. Call an ambulance.

HEAT CRAMP

Heat cramp involves painful muscular spasms as a result of loss of salt through sweating or profuse perspiration resulting from heat exhaustion. Heat cramps may occur during strenuous exercise or when working in an extremely hot environment or atmosphere.
SIGNS AND SYMPTOMS OF HEAT CRAMP         
  • Profuse perspiration.
  • Painful spasm of muscles, especially at the abdomen, arms and legs.
  • Flushed, moist and clammy skin.
FIRST AID FOR HEAT CRAMP
  1. Remove the casualty to a cool place.
  2. Lay the casualty down on the back, raise and support the legs, so as to improve blood supply to the brain.
  3. Remove excess clothing and sponge casualty with cold water.
  4. Give the casualty plenty of water, if possible, a weak salt solution of one teaspoon of salt per litre of water. You may also give sports drinks. Do not give tea, coffee, fizzy drinks or alcohol.
  5. Gently and slowly stretch the affected muscles.
  6. Call an ambulance or seek medical advice.

HEAT STROKE

Heat stroke is a condition or a state of sudden illness produced by prolonged exposure to excessive heat, characterized by a rapid rise of body temperature and sometimes in very serious cases, convulsion and coma. Heat stroke is an immediate, life-threatening emergency for which medical aid is urgently needed; this is because the sweat mechanism may be damaged
SIGNS AND SYMPTOMS OF HEAT STROKE
  • High body temperature (≥ 40.0°C)
  • Flushed and dry skin
  • Strong and rapid pulse
  • Deterioration in the level of consciousness
  • Fatigue
  • Headache and dizziness
  • Restlessness and confusion
  • Slurred speech
  • Lethargy
  • Casualty may develop seizure
FIRST AID FOR HEAT STROKE
  1. Remove the casualty to a cool place.
  2. Remove excess clothing and sponge casualty with cold water.
  3. Continually fan the casualty and sponge him with cold water or wrap the casualty in a cold, wet sheet and keep it wet until the temperature falls. You may immerse the casualty into cold water to the neck or place ice over them.
  4. If the casualty is conscious and alert, give the casualty plenty of water, if possible, a weak salt solution of one teaspoon of salt per litre of water. You may also give sports drinks. Do not give tea, coffee, fizzy drinks or alcohol.
  5. Monitor the casualty and prepare to resuscitate.
  6. Watch the casualty for repeated elevated temperature and deteriorating level of consciousness. If the casualty’s temperature starts to rise again, start the cooling process over again.
  7. Call an ambulance.