Adult CPR: technique and what actually matters

CPR (cardiopulmonary resuscitation) is the manual technique that keeps oxygenated blood flowing to the brain and vital organs when the heart has stopped pumping effectively. It buys time. It doesn’t restart the heart by itself in most cases; that usually takes defibrillation. What CPR does is keep the patient alive long enough for a defibrillator or paramedics to arrive and have something to work with.

The numbers matter. Brain damage from oxygen deprivation begins within four to six minutes of the heart stopping. After about 10 minutes without circulation, the damage becomes severe and largely irreversible. Survival from sudden cardiac arrest drops roughly 10 percent for every minute defibrillation is delayed. In a workplace where the ambulance might be five to fifteen minutes away, the difference between someone surviving and not surviving is most often whether a colleague started CPR.

For first aid purposes, anyone over eight years old is treated as an adult. Below that age the technique is modified (covered in the next article on this site).

Position and setup

The patient needs to be flat on their back on a firm surface. A carpeted floor or hard ground is fine. A mattress is not, because it absorbs the compressions and you can’t get effective depth. If you find someone in cardiac arrest on a bed, move them to the floor before starting CPR if you can do so quickly.

Kneel beside them at chest level. If possible, expose the chest (remove or open shirts and jackets), but don’t waste time on clothing if it’s slowing you down. Compressions through a thin shirt or jumper are still effective.

Hand position

Place the heel of one hand in the centre of the chest, on the lower half of the breastbone. Place your other hand on top of the first and interlock your fingers, keeping the fingers off the ribs. Your shoulders should be directly over your hands. Lock your elbows straight. You’ll be using your body weight to compress, not your arm muscles. If you try to do this with bent arms, you’ll be exhausted in under a minute.

Compression depth and rate

Push hard, push fast. The depth target for an adult is at least 5cm (about one-third of the chest depth). Research consistently shows that rescuers under-compress rather than over-compress. Don’t hold back. Cracked ribs are a possible side effect; cardiac arrest without intervention is a certain bad outcome.

Rate is 100 to 120 compressions per minute, roughly two per second. The Bee Gees song “Stayin’ Alive” famously sits in that tempo (103 bpm); other songs at that beat include “Another One Bites the Dust” (which lands awkwardly given the context), “Dancing Queen”, and “Crazy in Love”. Whatever helps you keep the rhythm.

After each compression, let the chest come back up fully before the next one. This recoil lets the heart refill. Leaning on the chest between compressions cuts your effectiveness by about 25 percent. Push down. Release fully. Repeat.

Count out loud as you go. “One, two, three, four…” up to 30. Counting keeps the rhythm and signals to anyone helping you what cycle you’re in.

Rescue breaths

After 30 compressions, give two rescue breaths. Open the airway with head tilt chin lift. Pinch the soft part of the nose closed. Use a barrier device (face shield or pocket mask) if one is available. Seal your lips around the patient’s mouth and blow steadily for about one second. The chest should rise. If it doesn’t, reposition the head and try the second breath. Don’t spend more than 10 seconds on the two breaths.

Then back to compressions. Thirty more, then two more breaths. Continue the 30:2 cycle until something changes.

Compression-only CPR

If you can’t or won’t do rescue breaths (no barrier device, blood or vomit around the mouth, you’re uncomfortable with mouth-to-mouth on a stranger), give compression-only CPR instead. Continuous compressions at 100 to 120 per minute, no breaths. ANZCOR says compression-only CPR is acceptable for adult cardiac arrest. Some CPR is dramatically better than no CPR. Don’t skip it because the breaths feel like a barrier.

When the AED arrives

If someone arrives with an AED while you’re doing CPR, don’t stop compressions to set it up yourself if there’s another person who can do it. Continue compressions while they apply the pads. When the AED says “analysing rhythm” or “stand clear,” pause compressions and stay back. Resume immediately after the shock (or after “no shock advised”).

You can find out more about how an AED works in our first aid online refresher course.

Swapping rescuers

Good CPR is hard work. Within two minutes most rescuers are pushing shallower than they realise. If there’s a second trained person available, swap every two minutes (roughly every five cycles of 30:2). The changeover should be fast: the new rescuer is in position by the end of your current 30 compressions, you give the two breaths, and they take over immediately. Aim for less than 10 seconds of interruption.

What if they vomit, or you crack a rib?

Vomiting during CPR is common. Roll the patient onto their side, wipe the mouth clear, roll them back, continue CPR. Don’t let it stop you.

Cracked ribs feel terrible (a soft crunch under your hands) but are a known and acceptable side effect. The patient is in cardiac arrest. Without CPR they will die. A cracked rib heals. Carry on.

When to stop

Continue CPR until one of three things happens. Signs of life return (coughing, moving purposefully, eyes opening). Emergency services arrive and take over. Or you’re physically unable to continue. Don’t stop because you think it’s been too long, or because nothing seems to be working. Patients have survived after 40 minutes or more of bystander CPR followed by professional resuscitation. Your job is to keep going until someone with more equipment takes over.

A workplace scenario

A driver in a transport yard collapses while doing a pre-trip walk-around. A workmate runs over, finds him face-down, rolls him onto his back. The scene is safe. He shakes his shoulders and shouts; no response. He yells to the foreman to call 111 and grab the AED from the office wall. He opens the airway with head tilt chin lift, looks for breathing for 10 seconds, sees one ragged gasp and nothing else.

Hands on the centre of the chest. Locks his elbows. Starts compressions, counting out loud, pushing to a count that sounds about two per second. After 30, two breaths. Back to compressions. The foreman returns with the AED about 90 seconds in. The workmate keeps compressing while the foreman switches it on and applies the pads. The AED says “stand clear, analysing.” Shock advised. Shock delivered. Resume CPR. Three cycles later the driver starts to gag and his eyes flicker. The paramedics arrive a minute after that.

That outcome is the difference good CPR makes. Not magic, just rhythm and pressure applied without giving up.