Principles of First Aid
 First Aid is the initial emergency care given immediately upon arrival at the scene to an ill or injured person and continues until professional medical assistance takes over the care of the casualty.
A first aider’s role is to:
• Preserve life.
• Protect the unconscious casualty.
• Prevent the condition worsening.
• Promote recovery.
• Call for medical assistance.

Priorities in an emergency
In all emergency situations, the first aider must:
• Ensure the safety of themselves, any bystanders and the casualty(s)
• Assess the situation quickly.
• Call for help 
• Commence appropriate treatment.
• Closely monitor the casualty for changes in condition

Objectives of Resuscitation
 To work efficiently, the human brain requires a constant supply of oxygen. A person who has stopped breathing will start to suffer irreversible brain damage within three to four minutes.
It is with this in mind that a first aider aims to provide basic life support to the casualty by administering an adequate supply of oxygen to the casualty and supporting circulation until signs of life return or until professional medical assistance arrives, and takes over treatment.
When calling for help, the “phone first” approach is recommended in life threatening situations. This allows for a quicker response time for the ambulance and is especially important for casualties suffering from a serious injury or conditions such as a cardiac arrest.
NOTE: Where there is more than one casualty, the care of an unconscious casualty has priority.

When the ambulance arrives, do not stop treatment until instructed by the ambulance officers. This allows the ambulance officers time to quickly prepare their equipment and get ready ready to take over treatment.
In rural locations, where single ambulance officers may respond, you may be asked to remain and assist the officer until further backup arrives.  In these circumstances follow carefully any directions given.

Please Remember
The first aider can then assist the Ambulance Officers by:
•Primary first aid treatment
•Information (such as: Initial presentation, History & Response to first aid treatment)
•Assistance if requested
It is important to remember that Ambulance Officers have a duty of care to the casualty and, as such, need to establish things for themselves despite what you, as a first aider, have told them. With this in mind, don’t be surprised if they question or re-assess the casualty, even though you may have presented a thorough history. Depending on the circumstances, they may remove any bandages that you have applied to assess the injury themselves and apply special, purpose made equipment
.
Infection Control
There is a risk of cross-infection as diseases can pass between the casualty and first aider and between casualties. It is therefore a requirement of the first aider to take reasonable precautions to prevent cross-infection.
 It is essential that as a first aider, you approach all situations involving body fluids: saliva, vomit, blood, urine and faeces etc as potentially infectious, adopting appropriate precautions to protect yourself.
Precautions to be taken:
• Wash your hands before and after treatment.
• Use disposable gloves when treating a casualty.
• Change gloves before treating a different casualty.
• Use protective aprons and eye protection where available.
• Cover any open cuts you may have with waterproof dressings.
• Wash off any body fluids immediately.
• Dispose of used gloves and contaminated waste correctly.
• Wash re-usable equipment in an anti-bacterial solution
• Use protective masks with a one-way valve and/or viral filter when performing Rescue Breathing.
Although the risks of contracting a serious disease are extremely low, there are still some very basic procedures to follow in the immediate treatment of an exposure.
•Wash the wound thoroughly with anti-bacterial hand wash or soap and water if unavailable.
•Seek treatment from a doctor as soon as possible for preventative medication and blood screening.
If blood/body fluids come into contact with your intact skin:
•Wash the area thoroughly with anti-bacterial hand wash or soap and water if unavailable.
If blood/body fluids come into contact with an open wound on your skin:
•Wash the area thoroughly with anti-bacterial hand wash or soap and water if unavailable.
•Seek treatment from a doctor as soon as possible for preventative medication and blood screening.
If eyes are contaminated:
•Rinse gently with water making sure to wash under the eyelid.
•Seek treatment from a doctor as soon as possible for preventative medication
If mouth is contaminated:
•Spit out and rinse with water.
•Seek treatment from a doctor as soon as possible for preventative medication
Human Anatomy and Body Function
As a first aider, you are there to assist a person who has been injured or is suffering any form of illness and therefore you need to have a basic understanding of the human anatomy and how the body functions.

The Nervous System
The nervous system comprises the brain, spinal cord and nerves.
The Brain
 The brain is enclosed in and protected by the skull. It is a very delicate organ that can be damaged easily. The brain analyses thoughts and functions. The brain stem contains the medulla oblongata, which controls the breathing rate and depth, the rate and force of heart contractions and it controls the size of the blood vessels by constricting (shrinking) and dilating (expanding).
The Spinal Cord
The spinal cord contains the sensory and motor control nerves. The spinal cord runs down from the brain, protected by the spinal column and finishes at about lumbar three (3) where it branches off into peripheral nerves.
The Nerves
 The peripheral nerves contain motor and sensory nerves, which send and receive electrical impulses. Motor nerves are responsible for transmitting the electrical impulses for muscle movement. Sensory nerves transmit impulses for sight, hearing, touch etc to the brain.

The Respiratory System
 The function of the respiratory system is to inhale the air we breathe, which allows oxygen to pass into the blood stream and waste products (carbon dioxide) to be removed from the blood stream and to be exhaled.
When you breathe in, air enters through the nose. The nasal cavity warms and filters the air we breathe before it enters the trachea. The trachea then divides into the left and right bronchi. The bronchi then divide into what are known as alveoli, which are small air sacs in the lungs. This is where the oxygen we breathe in enters the blood stream and when we breathe out this removes waste product (carbon dioxide) from the blood stream.
The air we breathe contains about 21% oxygen. The rest is made up of different gases. Our body uses approximately 5% of this oxygen, exhaling the remaining 16%. Therefore what we exhale has sufficient oxygen content for the purposes of Rescue Breathing

The Cardiovascular System 
The heart, blood vessels and blood make up the cardiovascular system.

The Heart
The heart is a four-chambered pump. Used blood is returned to the heart via the top (superior) and bottom (inferior) vena cava (largest veins in the body).
The blood enters the heart via the right atrium and is then pumped into the right ventricle. When the ventricle contracts, the blood is pumped to the lungs for the exchange of oxygen and the removal of carbon dioxide.
Once this process is complete, the oxygenated blood returns to the heart via the left atrium and is then pumped into the left ventricle. When the ventricles contract the blood is pumped back into the body via the aorta (the largest artery in the body). 
Blood
Blood consists of red and white blood cells, platelets and plasma. 
The red blood cells carry oxygen and waste products (carbon dioxide). White blood cells help fight infections, platelets help the blood to clot and plasma represents the fluid content of the blood.
In an adult, with each beat of the heart, approximately seventy (70) milliltres of blood is pumped into the circulatory system. An average heart rate is approximately seventy-two (72) beats per minute. The heart therefore pumps approximately five (5) litres of blood per minute.
Blood vessels (arteries, veins and capillaries)
 
Arteries carry blood away from the heart. The arteries are under constant pressure from the heart pumping. This pressure as the heart pumps can be felt as a pulse.  Pulses are best felt on the neck (carotid pulse), in the groin (femoral pulse) or on the wrist (radial pulse). In infants a good place to check for a pulse is on the inside of the elbow (brachial pulse).
If an artery is damaged (lacerated etc), it will be under high pressure causing the blood to spurt out. The blood will be bright red in colour, due to the high levels of oxygen.
Veins
Veins carry blood back to the heart to be oxygenated and for the removal of waste products (carbon dioxide). So the cycle starts again. The veins are not under as much pressure as the arteries. If a vein is damaged (lacerated etc) the blood will flow freely. It will be dark red in colour as the blood is not as highly oxygenated and is carrying waste product back to the heart.
Capillaries
Capillaries are minute vessels containing both arterial and venous blood. It is here where the exchange of oxygen, carbon dioxide and other nutrients occurs with the cells. The capillaries are also not under as much pressure as the arteries so if damaged (by abrasion etc) the blood will only ooze out. The colour of the blood may be bright or dark red as it contains both arterial and venous blood.

 What are the common or classic symptoms of a heart attack ?
• A pain in the centre of the chest.
• The pain can spread to the arms, neck or jaw.
• Some people can feel sick or sweaty as well as having central chest pain.
• Some people can feel short of breath as well as having central chest pain.
• A dull pain, ache, or ‘heavy' feeling in the chest .
• A mild discomfort in the chest that makes you feel generally unwell.
• The pain in the chest can spread to the back or stomach.
• Some people say that the chest pain feels like a bad episode of indigestion.
• Some people can feel a bit light-headed or dizzy as well as having chest pain.

The Digestive System
The digestive system includes the stomach, small intestine, liver, pancreas and large intestine. The role of the digestive system is to break down the food and fluids that we eat and drink. It is mixed with gastric juices followed by pancreatic juices. Once broken down, the nutrients, fats, energy etc are distributed to the body via the circulatory system. The waste products of this process leave the body via the bowel and the urinary system.

The Lymphatic System
The lymphatic system is our defence against infections and toxins , such as poisons. The lymph glands are located in the neck, armpits and groin. As infection/poison travels through the body via the lymphatic system, the lymph glands trap, break down and dispose of the infection/poison. This prevents the infection/poison re-entering the circulatory system. When an infection/poison has been trapped by the lymph glands, these glands become swollen, enlarged and painful.