Environmental Emergencies

K.S. ChewLecturer/Emergency Physician

School of Medical SciencesUniversiti Sains Malaysia

Introduction

HUMAN BODY ENVIRONMENT

Hemostasis Interaction

MAINTAIN A STABLE ENVIRONMENT FOR THE BODY METABOLISMS

Sources of Heat Loss

• Conduction– Heat lost to a cooler object with direct contact with the body

• Convection– Heat lost to surrounding air which then carried away by

convection currents• Radiation

– Heat lost in form of infra-red. For an unclothed person, this way accounts for ~ 60% of total heat loss

• Evaporation– Heat is lost as water evaporates (changing from liquid to vapor)

from skin and lungs at rate of ~ 600 ml/day • Respiration

– Combination of evaporation, convection and radiation

Temperature Regulation

• Thermoregulation is coordinated by anterior hypothalamus

• This centre receives information about environmental temperature from thermoreceptors in skin and core temperature from thermoreceptors in anterior hypothalamus itself.

Thermoregulation• Cutaneous blood vessels

– Vasodilation– Vasoconstriction

• Sweating• Shivering• Increasing/Decreasing Activity will cause

corresponding increases in heat production and decreases in heat production.

• Behavioral Responses

DROWNING AND HYPOTHERMIA

Drowning Sequence• Panic, hyperventilation, automatic

swimming movements• Uncontrolled breaths; increased amounts

of swallowed water• Vomiting & gasping with aspiration• Violent struggle before become

unconscious• Lost airway reflexes and passive entry of

fluid into airway

Drowning

First Aid

• ALWAYS be aware of your own personal SAFETY FIRST

• Whenever possible, attempt to save the drowning victim without getting into the water.

• HOW?– Reaching with a rescue aid – throwing rope,

buoyant rescue aid, stick etc

First Aid

• Alternatively, use rescue boat or other water vehicle to assist with the rescue

• If entry into water is a must, take a buoyant rescue aid / life jacket / floatation device with you.

• The key principle is TO REMOVE the patient from the water by the FASTEST and SAFEST means available.

Drowning Threats In Children

• A child can drown in as little as two inches of water

• A child can drown in less time than it takes to answer the telephone

• In California, 67% of all drowning deaths occur in their own backyard pool, spa or hot tub.

• And 25% of all children who have drowned or nearly drowned have had swimming lessons.

Remember

Drowning is a silent killer!The victims don't cry for help. Because, if they are not getting enough air to breathe, they do not have the extra air needed to call for help.

First Aid

• Put patient in horizontal position. Do not raise the legs as this would cause cold blood to flow from legs to body core and adversely affect the heart

• Do not let patient walk. • Do not massage the body.

When the patient in cardiac arrest

• Proceed with ABC as for other cardiac arrest victims

• DO NOT withhold resuscitation unless there is obvious lethal injuries or the body is completely frozen making CPR difficult– The brain has a 10 times higher chance to

tolerate cardiac arrest in hypothermic condition than in normal condition

Hypothermia• When body temperature less than 35ºC• Can occur even in people with normal

thermoregulation that – exposed to cold environments, especially in wet or

windy conditions– following immersion in cold water

• Arbitrarily classification:– Mild 32-35ºC– Moderate 30-32ºC– Severe less than 30ºC

The HELP Position• A life jacket helps in

two ways: – it reduces the need to

move– it helps insulate

against heat loss. • With the life jacket,

draw knees up into a H.E.L.P (Heat Escape Lessening Position) position

Heat Related Emergencies

Girl Locked In Van DiedKUALA KUBU BARU: A six-year-old girl who was locked inside a van for almost three hours died of heat exhaustion five days after she was found slumped inside the van.

Apparently the girl dozed off in the van while on her way to herkindergarten in Bukit Sentosa near Bukit Beruntung at 7.05am last Wednesday.

The heat caused the organs in Syarifah Fatin Syahirah SyedAhmad Najmi's body to fail……..

(The Star Online, Tuesday April 11, 2006)(www.thestar.com.my)

Hyperthermia

• Occurs when body’s thermoregulation fails• Hyperthermia maybe exogenous or

endogenous• Exogenous

– Heat Stress – including heat cramps, heat syncope, heat cramps

– Heat exhaustion– Heat stroke

Heat CrampsHOT ENVIRONMENTAL TEMPERATURE

VASODILATATION ON SKIN SURFACE

WATER AND ELECTROLYTES LOSS THROUGH SWEAT

PAINFUL MUSCLE CRAMPS DUE TO ELECTROLYTE LOSSES

First Aid

• Remove victim from the environment• Drink water, preferably with oral

rehydration salt or sport drinks– Salt tablet not advised as it is not readily

absorbed and can cause stomach irritation• Gentle elevation / stretching of cramped

muscle

Heat Exhaustion• Severe dehydration (water and sodium

loss)– Loss of about 1 – 2 L of water per hour when

working under hot environment• Signs and symptoms include

– Severe thirst with fatigue– Nausea and vomiting, sometimes diarrhea– Headache, anxiety

• If untreated can progress to heat stroke

LOSS OF THERMOREGULATORY CONTROL BY HYPOTHALAMUS

UNCOMPENSATED HYPERTHERMIA

CELLULAR DEATH AND ORGANS DAMAGE

HIGH CORE BODY TEMPERATURE (E.G. > 40.6ºC)

Signs and Symptoms of Heat Stroke

ORGAN SYSTEM DAMAGED SIGNS AND SYMPTOMS

Central Nervous system Confusion, disorientation, seizure

Sweat Glands Cessation of sweating, dry hot skin

Respiratory system Deep breathing initially, then shallow and rapid

Cardiovascular system Tachycardia, later bradycardiaHypotension with low or absent diastolic reading

Thermoregulatory center of anterior hypothalamus

High core body temperature (e.g. > 40.6C)

First Aid• Move victim to cool place• Initiate rapid cooling

– Remove victim’s clothing– Cover victim with sheets soaked in tepid

water– Spray with water– Fanning– Ice bags at large vein areas – groins, armpits

• Seek medical help

Preventing Heat Illnesses• Avoid dehydration

– Drink one cup (about 8 ounces) every 20 minuteswhile working

– Thirst not always a good indicator of adequacy of fluid intake

– If you drink water only when you feel thirsty, you may not be able to adequately replace the water loss

– An average person, would only be able to drink up to one pint (16 ounces) of water

– It takes time for the water to be absorbed – so there’s no point drinking too much water at any one time.

Preventing Heat Illnesses• Cool water is easier to be absorbed from the GI

tract than warm water• Most people require only water but commercial

sport drinks (that can be absorbed faster and resemble more closely to sweat) are useful in vigorous sport activities.

• Drinking too much water with profuse sweating for a long periods can result in water intoxication (hyponatremia).

Preventing Heat Illnesses• Fruit juices range from 11% - 18% of sugar and

have a longer time for absorption.• Avoid coffee or tea as they contain caffeine, a

diuretic that increases water loss through urination

• Dress in loose, light-colored clothing to reflect heat

• Rest frequently, preferably under shade• Apply cool water on exposed areas