# First Aid/C for Compressions
## Principles

The human heart is an electro-mechanical pump, circulating nourishing blood throughout the body. If beating stops, the brain, lungs and even the heart itself stop receiving oxygen and perish. Rescuers can use a technique called chest compressions to squeeze the heart from outside the patient's chest, helping to circulate blood around. When performing chest compressions during CPR, you are helping move the oxygen you delivered through rescue breathing where it is needed.
Chest compressions are often started before any other intervention in an emergency setting, because even blood that has already passed through the body has oxygen remaining to be used. Using compressions to pump that existing blood around can help buy the patient more time. This is the reason that CPR can be done "compression only", or without rescue breathing. Once compressions start, they must continue for as long as possible.

## Technique

The goal is always to compress in the center of the chest, regardless of the shape or size of the patient. This means that compressions are to performed on the sternum or breastbone of the patient, in line with the casualty's armpits or nipple line.
* For adults (>8) - place the heel of one hand in the centre of the chest, approximately between the nipple line (on adult males - for females, you may need to approximate the ideal position of this line due to variations in breast size and shape). You may also use the bottom of the casualty's armpits as a reference mark. Bring your other hand to rest on top of the first hand, and interlock your fingers. Bring your shoulders directly above your hands, keeping your arms straight. You should then push down firmly onto the heel of the lower hand, depressing the chest 5–6 cm (2-2.5inches).
* For children (1-8) - place the heel of one hand in the centre of the chest, approximately between the nipple line. Bring your shoulder directly above your hand, with your arm straight, and perform compressions to at least one third (1/3) the depth of the chest with one arm only.
* For infants (<1yr) - Use your forefinger and middle finger only. Place your forefinger on the centre of the child's chest between the nipples, with your middle finger immediately below it on the chest, and push downwards using the strength in your arm, compressing the chest at least one third (1/3) of its depth. For newborns and small infants, you can hold the child in your opposite arm (head in your palm, feet at your elbow) for easier access.
Give 30 compressions in a row, and then two (2) rescue breaths.
Then restart your next cycle of compressions

## Making compressions effective

You MUST allow the ribs to come all the way back out after each compression, followed by a brief pause. This allows the heart's chambers to refill. Spacing compressions too close together will lead to them being ineffective.
You are aiming for a rate of 100 compressions per minute, which includes the time to give rescue breaths. In practice, you should get just over 2 cycles of 30 compressions in along with breaths per minute.
Almost everyone compresses the chest too fast - Experience shows that even well trained first aiders tend to compress the heart too fast. The rate you are aiming for is only a little over one per second. The best equipped first aid kits should include a Metronome with an audible 'beep' to match your speed to. Many public access defibrillators have these included in their pack. If one is not available, count the number of compressions with the word 'and' between them. When you press down on the chest, say the number, when the chest rises say 'and'. this way, you will be saying 'one-and-two-and-three...'
The patient should be on a hard surface - If the patient is in bed or a similar cushioned area, moving them to the floor will help assure you are compressing their chest and not the mattress or couch cushions. If moving the casualty is impractical, a hard, flat board can be placed behind them to make compressions more effective.
Keep your arms straight - A lot of television and films show actors 'performing CPR' bending their elbows. This is not effective - you should always keep your arms straight, with your elbows locked and directly above your hands.
It often helps to count out loud - You need to try and get 30 compressions per cycle, and it helps to count this out loud or under your breath. In such a stressful situation, you will be anxious and unable to count out loud for the duration, but ensure you keep counting, even if it's in your own mind.
If you lose count, don't stop, just estimate - It is important to carry on once you've started, so if you lose count, don't panic, and simply estimate when 30 compressions is over, and do 2 breaths, then start over counting again. Avoid any interruptions in CPR.
You are likely to break ribs - When performing compressions, especially on the elderly, you may find yourself breaking the patient's ribs. This often feels like flicking the finger of one hand against the palm of another. This is to be expected during CPR, and you should carry on regardless. It is a sign that you are performing good, strong compressions. Oftentimes the cracking sound you will hear is just the cartilage of the ribs and sternum breaking, and not the bones themselves. If bystanders are concerned about injury to the patient, you may want to remind them of the life over limb principle and assure them that it is a normal occurrence, and what you are doing is critically important.
Chest compressions are tiring - This is especially true if you are performing both rescue breathing and compressions by yourself. Studies show that the efficacy of CPR drops when one rescuer performs compressions for an extended time. Hospital emergency rooms switch personnel performing compressions often for this reason. If you are with someone else trained in CPR, rotate between compressions and rescue breaths.

## When to Stop

You should continue giving the patient CPR until:
* The casualty starts breathing spontaneously - This occurs very infrequently, and does not include gasping, called agonal breathing. Patients are also likely to make sighing noises or groans as you perform chest compressions - this is just the sound of air trapped in the lungs being forced out, and you should not stop CPR if these noises are heard.
* The patient vomits - This is an ACTIVE mechanism, meaning the patient moves and actively vomits. Not to be confused with regurgitation, where stomach contents make their way passively in to the mouth. If the casualty vomits, roll them to their side, clear the airway once they're done vomiting and reassess ABCs. Vomit is obviously undesirable for the person performing CPR. Attempt to clear the mouth with your fingers (preferably while wearing a barrier device) and continue CPR. If you are without barrier device and feel uncomfortable giving rescue breaths, give chest compressions only.
* Qualified help arrives and takes over. This could be a responder with a defibrillator, the ambulance service or a doctor. DO NOT STOP until instructed to. They are likely to require time to set up their equipment and evaluate the patient (as you did at first) and you should continue with CPR until instructed to stop. The emergency medical personnel are used to working around people, and may do things like place defibrillator patches while you continue. By continuing CPR, you are keeping the medical personnel free to perform other tasks.
* You are unable to continue - CPR is physically very demanding, and continued periods can be exhausting. Try to change places frequently with another trained rescuer to lessen the chance of exhaustion.
* You put yourself in danger by continuing - Hazards may change, and if your life is endangered by a new hazard, you should stop CPR. If possible, remove the patient from the hazardous situation as well, but never at the risk of your own life or health.