23.2 — CPR and Choking

Survival from cardiac arrest falls by around 7 to 10 percent for every minute without CPR and defibrillation.

After ten minutes, survival is close to zero.

An ambulance takes on average 7 to 10 minutes to arrive in a city, and considerably longer elsewhere.

Which means the person standing there decides the outcome. Not the paramedics, not the hospital. The bystander.

And bystander CPR roughly doubles or triples survival. That is the whole argument for this page.

What cardiac arrest actually is

The heart stops pumping effectively.

Not a heart attack, and the confusion between the two is worth clearing up:

A heart attack is a blockage in a coronary artery. Heart muscle is dying. The person is usually conscious and in pain. It can cause cardiac arrest, and most of the time it does not (Chapter 23.4).

Cardiac arrest is the pump stopping. The person collapses, becomes unresponsive, and stops breathing normally within seconds.

In cardiac arrest, blood stops moving. Brain cells begin to die within about 4 to 6 minutes without oxygen (Chapter 11.10).

Chest compressions keep blood moving. They do not restart the heart. They buy time — keeping the brain and heart muscle alive until a defibrillator can restart a coordinated rhythm.

Which is why compressions and a defibrillator work together and neither alone is enough.

Recognising it

Three things, and only three:

Unresponsive.

Not breathing, or not breathing normally.

And that is enough. Start.

Do not check for a pulse. Even trained clinicians take too long and get it wrong under pressure.

Agonal gasping is the trap. Slow, irregular, noisy, snoring or sighing gasps occur in a large proportion of cardiac arrests in the first minutes. They look like life. They are the brainstem's dying reflex.

If the breathing is not regular, quiet and effective, treat it as absent.

A short seizure at the moment of collapse is also common in cardiac arrest, and is another reason people delay.

The cost of starting CPR on someone whose heart has not stopped is small. They will usually respond, move, or tell you to stop. The cost of not starting on someone whose heart has stopped is their life.

When in doubt, start.

Adult CPR — step by step

1. Danger, response, shout for help

As in Chapter 23.1.

2. Open the airway and check breathing

Head tilt, chin lift. Look, listen, feel for up to 10 seconds.

3. Call for an ambulance and get a defibrillator

If someone else is there: send them to call and to fetch the nearest defibrillator while you start compressions.

If you are alone: call the emergency number yourself, put the phone on speaker on the floor beside you, and start compressions. Do not go looking for a defibrillator if it means leaving them for more than a few seconds.

The call handler will guide you and will count out loud for you if you need it. Let them. They do this all day.

Many countries have apps and registries that alert nearby trained responders and locate the nearest defibrillator.

4. Chest compressions

Position:

Kneel beside them, level with the chest.

Place the heel of one hand in the centre of the chest, on the lower half of the breastbone. The centre of the chest between the nipples is close enough — do not spend time measuring.

Place your other hand on top and interlock your fingers. Lift your fingers so pressure goes through the heel of the hand, not the ribs.

Position your shoulders directly above your hands, arms straight, elbows locked.

Push down using your body weight, not your arm muscles, because arms tire within a minute and body weight does not.

Technique:

Depth: 5 to 6 centimetres in an adult. About one third of the chest depth.

That is deeper than almost anyone expects. The single commonest fault in bystander CPR is compressions that are too shallow. You are trying to squeeze a fist-sized muscle between the breastbone and the spine hard enough to push blood around the body.

Rate: 100 to 120 compressions per minute.

That is roughly two per second. The tempo of "Stayin' Alive" by the Bee Gees is famously at exactly the right rate, and so is "Baby Shark", "Another One Bites the Dust" and "Dancing Queen". Pick one and think it.

Allow full recoil. Let the chest come all the way back up between compressions without taking your hands off.

This matters more than it sounds. The heart refills during the recoil. Leaning on the chest between compressions is the second commonest fault, and it reduces the blood you move by a large fraction.

Minimise interruptions. Every pause drops the pressure in the arteries, and it takes several compressions to build it back up. Keep pauses under 10 seconds.

About the ribs: broken ribs and cartilage occur in a substantial proportion of CPR. You may feel or hear cracking.

Keep going. Broken ribs heal. Brains do not. Stopping because of the sound is a well-documented reason CPR fails.

5. Rescue breaths — or not

The standard is 30 compressions followed by 2 rescue breaths, repeating.

If you are unwilling or unable to give rescue breaths — for any reason, including not wanting to put your mouth on a stranger's — do compression-only CPR.

Continuous chest compressions with no breaths.

And that is a genuine recommendation, not a compromise. For an adult with a sudden collapse from a cardiac cause, compression-only CPR by a bystander gives similar survival to compressions with breaths in the first several minutes, because there is still oxygen in the blood and the lungs, and what is missing is circulation.

Anything is enormously better than nothing.

If you do give breaths:

After 30 compressions, open the airway with head tilt and chin lift.

Pinch the soft part of the nose closed with the thumb and index finger of your hand on the forehead.

Take a normal breath, seal your lips around their mouth, and blow steadily for about 1 second, watching the chest rise.

Take your mouth away, let the chest fall, and give a second breath.

Then return to compressions immediately. Both breaths should take no more than 10 seconds in total.

If the chest does not rise: recheck the airway, remove any visible obstruction, and check the seal. Do not attempt more than two breaths before returning to compressions.

Use a face shield or pocket mask if you have one.

6. Keep going until

Professional help takes over.

The person shows definite signs of life — moving, opening their eyes, breathing normally.

Or you are too exhausted to continue.

Swap with another rescuer every 2 minutes if you can, because compression quality falls off measurably after that even when the rescuer does not feel tired. Swap fast — during the pause for a breath if possible.

Defibrillators

An automated external defibrillator — an AED — is designed to be used by someone with no training at all.

It will not shock someone who does not need it. It analyses the rhythm and only delivers a shock if the rhythm is one a shock can fix. You cannot harm someone with it by mistake.

How to use one:

1. Switch it on. It starts giving spoken instructions immediately. Follow them.

2. Expose the chest. Cut or tear clothing off. Wipe the chest dry if wet. Shave excessive hair only if a razor is in the kit and it takes seconds.

3. Attach the pads as shown in the pictures on them — one below the right collarbone, one on the left side of the chest below the armpit.

4. Do not touch the person while it analyses.

5. If it advises a shock: shout "stand clear", check nobody is touching them, and press the flashing button.

6. Resume compressions immediately after the shock — do not wait to see what happens.

7. It will re-analyse every 2 minutes. Follow it.

Special situations:

Pacemaker or implanted device — a lump under the skin. Place the pad at least 8 centimetres away from it.

Medication patches — remove them and wipe the skin, because they can arc.

Wet person or wet ground — move them to a dry surface if you can do it in seconds, and dry the chest. A slightly damp environment is not a reason to withhold a shock.

Metal surface — fine, as long as nobody is touching the person.

Pregnancy — use it normally.

Children under 8 or under 25 kg — use paediatric pads or a paediatric setting if available. If not available, use adult pads — place one on the front of the chest and one on the back if the pads would overlap. An adult defibrillator on a child is far better than no defibrillator.

Children and babies

And this is where the sequence genuinely changes, for a reason worth understanding.

In adults, cardiac arrest is usually a sudden heart rhythm problem, and the blood still contains oxygen.

In children, cardiac arrest is usually the end result of a breathing problem — choking, drowning, severe asthma, infection. By the time the heart stops, the blood is already low on oxygen.

Which is why children get breaths first, and why breaths matter far more in children than in adults.

Child — over 1 year to puberty

1. Check danger, response, airway, breathing.

2. Give 5 initial rescue breaths.

3. Then start CPR at 30 compressions to 2 breaths if you are alone, or 15 to 2 if you are trained and there are two rescuers.

4. If you are alone, do 1 minute of CPR before leaving to call for help — unlike an adult, where you call first. Use a speakerphone if you have one so you do not have to leave at all.

Compressions: one or two hands, whichever gets you to a depth of about one third of the chest — roughly 5 centimetres. Same rate, 100 to 120.

Baby — under 1 year

1. Check response by tapping the foot and calling. Never shake a baby.

2. Open the airway to a neutral position — the head flat, not tilted back. A baby's head is large and the neck is soft, and tilting it back kinks the airway closed rather than opening it.

3. Give 5 initial rescue breaths, covering both the mouth and the nose with your mouth, and blowing only gently — a puff from your cheeks, enough to make the chest just visibly rise. A full adult breath will damage the lungs.

4. Compressions: two fingers in the centre of the chest, just below the nipple line. Depth about 4 centimetres, again about a third of the chest. Rate 100 to 120.

Two-thumb technique if there are two rescuers — hands encircling the chest, thumbs on the breastbone.

5. 30 compressions to 2 breaths alone, 15 to 2 with two trained rescuers.

6. One minute of CPR before calling if alone.

Choking

And the first question is the one that decides everything: can they cough?

Mild obstruction — they can cough, speak or breathe

Encourage them to cough.

A cough generates far more pressure than any manoeuvre you can perform.

Do not slap their back, do not put fingers in their mouth, do not give them water. Stay with them and watch.

Most choking resolves this way.

Severe obstruction — they cannot cough, speak or breathe

Signs: silence; clutching the throat; distress and panic; a silent cough; wheezing or nothing at all; turning blue; and rapid loss of consciousness.

Act immediately.

Adult and child over 1:

1. Five back blows.

Stand to the side and slightly behind. Support their chest with one hand and lean them well forward — so that anything dislodged comes out of the mouth rather than going further down.

Give five sharp blows between the shoulder blades with the heel of your hand.

Check after each one. Five separate attempts, not a rhythm of five.

2. Five abdominal thrusts.

Stand behind them and put both arms around the upper abdomen.

Make a fist and place it between the navel and the bottom of the breastbone.

Grasp the fist with your other hand and pull sharply inwards and upwards.

Five times, checking after each.

3. Alternate five back blows and five abdominal thrusts until it clears or they become unresponsive.

If they become unresponsive: lower them to the ground, call an ambulance, and start CPR beginning with chest compressions. The compressions generate pressure that can dislodge the object, and by that point the airway must be cleared and circulation maintained regardless.

Check the mouth each time before giving breaths and remove anything you can see.

Anyone who has received abdominal thrusts should be assessed medically afterwards, because of the risk of internal injury.

Babies under 1 — never abdominal thrusts:

Abdominal thrusts can rupture a baby's liver. Use chest thrusts instead.

1. Five back blows. Lay the baby face down along your forearm, head lower than the body, supporting the head and jaw with your hand — and do not compress the soft tissue under the jaw. Five sharp blows between the shoulder blades with the heel of your hand.

2. Five chest thrusts. Turn the baby face up along your other forearm, still head-down. Two fingers on the breastbone, in the same place as compressions — five sharp thrusts, sharper and slower than CPR compressions.

3. Alternate, checking the mouth each time, and never sweep blindly with a finger.

If they become unresponsive: start infant CPR.

If you are choking alone

Call the emergency number even if you cannot speak — in many countries an open line with no speech triggers a response, and some systems allow tapping the handset.

Give yourself abdominal thrusts, or press your upper abdomen hard against a firm edge — the back of a chair, a worktop, a railing — and thrust sharply.

Special situations

Pregnancy — for CPR, place a firm object under the right hip or have someone manually push the uterus to the left, because the pregnant uterus compresses the main vein returning blood to the heart. Compressions and defibrillation are otherwise the same.

For choking in advanced pregnancy, use chest thrusts rather than abdominal thrusts.

Drowning — give 5 initial rescue breaths before compressions, because it is a breathing-caused arrest (Chapter 23.10).

Trauma — control catastrophic bleeding first.

Hypothermia — continue CPR for longer, and do not conclude death until the person has been rewarmed. "Not dead until warm and dead" is a real rule, and people have survived prolonged arrest in extreme cold with full recovery (Chapter 23.10).

Opioid overdose — give naloxone if available, and do compressions and breaths, because this too is a breathing-caused arrest (Chapter 23.6).

Afterwards

If they recover: place them in the recovery position and monitor continuously, because arrest can recur.

For the rescuer: performing CPR is distressing, and most attempts do not succeed. That is not a failure of the person who tried.

Debriefing and support after an attempt is normal and worth seeking, and many ambulance services offer it.

And the fact worth ending on: someone who receives immediate bystander CPR has two to three times the chance of surviving compared with someone who does not.

You cannot make a dead person worse.

What the next page fixes

Chapter 23.3 covers severe bleeding — how to stop it, when to use a tourniquet, and how to deal with wounds you should not remove anything from.