CPR and Choking: What to Do in the First Three Minutes
Most people who witness a cardiac arrest do nothing, usually because they are afraid of doing it wrong. The relevant fact is that doing nothing is the worst available option. Imperfect CPR substantially outperforms no CPR.
Recognising cardiac arrest
- Unresponsive to shouting and shaking
- Not breathing, or breathing abnormally
Agonal breathing is the critical trap. In the first minutes of cardiac arrest, a person may make occasional gasping, snoring or gurgling sounds. It looks like breathing, and it is not. If breathing is not normal and regular, treat it as cardiac arrest.
Do not spend time checking a pulse. Lay rescuers are unreliable at it, and the time is better spent starting compressions.
The sequence
- Check for danger to yourself.
- Check response. Shout and shake the shoulders.
- Shout for help. Ask someone specific to call emergency services and fetch a defibrillator. Pointing at one person works better than a general appeal.
- Open the airway. Head tilt, chin lift.
- Check breathing for no more than 10 seconds. Look, listen, feel.
- If not breathing normally, start compressions immediately.
Compressions
- Heel of one hand in the centre of the chest, on the lower half of the breastbone. Other hand on top, fingers interlocked
- Arms straight, shoulders directly above the hands
- Press down 5 to 6 cm in an adult
- 100 to 120 compressions a minute
- Allow the chest to recoil fully between compressions; leaning on the chest reduces effectiveness
- Minimise interruptions
The tempo matches a number of well-known songs; any of them will do if it keeps you in range.
Hands-only CPR is acceptable and recommended for untrained rescuers, and for anyone unwilling or unable to give rescue breaths. Continuous compressions alone are far better than nothing and avoid the hesitation that stops people starting.
If trained and willing, use 30 compressions to 2 rescue breaths.
Expect to break ribs. It happens frequently and is not a reason to stop or to press more gently. A broken rib heals; a brain without circulation does not.
Swap rescuers every two minutes if possible, because compression quality falls off quickly with fatigue, and the rescuer rarely notices.
Defibrillators
An automated external defibrillator analyses the heart rhythm and delivers a shock only if one is needed. It will not shock someone who does not need it, which means you cannot harm a person by attaching it.
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To use: switch it on and follow the spoken instructions. Attach the pads to bare skin as shown on the diagram, stand clear while it analyses, and press the shock button if instructed. Resume compressions immediately afterwards.
Dry the chest if wet. Remove a medication patch if one is under a pad. Avoid placing a pad directly over a pacemaker bump.
Early defibrillation is the single largest determinant of survival in shockable rhythms, and every minute of delay costs roughly ten per cent of the chance of survival.
For children and infants
The principles are the same with adjustments.
- Start with 5 rescue breaths before compressions, because cardiac arrest in children is more often caused by a breathing problem
- Compress about one third of the chest depth
- Children: one or two hands. Infants: two fingers, or two thumbs with hands encircling the chest
- Use paediatric pads on a defibrillator if available; if not, adult pads are better than no defibrillation, placed front and back on an infant
Choking
Mild obstruction: the person can cough, speak or breathe. Encourage coughing. Do not intervene; coughing is more effective than anything you can do.
Severe obstruction: the person cannot speak, cough or breathe, may clutch the throat, may make high-pitched sounds or none, and will become cyanosed.
For an adult or child over one:
- Give 5 back blows between the shoulder blades with the heel of your hand, leaning them forward
- If unsuccessful, give 5 abdominal thrusts. Stand behind, make a fist above the navel and below the breastbone, grasp with the other hand, pull sharply inward and upward
- Alternate 5 and 5 until the obstruction clears or the person becomes unresponsive
- If they become unresponsive, lower them to the ground, call emergency services and start CPR. Compressions can dislodge the obstruction
For an infant under one: do not use abdominal thrusts. Alternate 5 back blows, face down along your forearm with the head lower than the body, and 5 chest thrusts, face up, using two fingers on the lower half of the breastbone.
For a pregnant or very large person: use chest thrusts instead of abdominal thrusts.
If choking alone: call emergency services even if you cannot speak, as many systems can locate a silent call, then perform abdominal thrusts against a chair back or counter edge.
Anyone who has received abdominal thrusts should be medically assessed afterwards, because of the possibility of internal injury.
The recovery position
For someone who is unresponsive but breathing normally: roll them onto their side, head tilted back to keep the airway open, with the lower arm extended and the upper leg bent to stabilise. Monitor breathing continuously and be prepared to start CPR if it stops.
The short version
If someone is unresponsive and not breathing normally, including occasional gasps, call for help, start hard fast compressions in the centre of the chest, and send someone for a defibrillator. Hands-only is fine. For choking, five back blows then five abdominal thrusts, alternating, and start CPR if they go unresponsive. The only serious mistake is hesitating.