First Aid Basics: How to Recognise and Respond to Medical Emergencies

Bystander first aid is not a substitute for professional medical care, but it can keep a person alive until paramedics arrive. According to the British Red Cross, the same basic sequence applies to almost every emergency: check whether the person is responsive and breathing, call the emergency number, and then give care while waiting for help.

CPR: someone is unresponsive and not breathing

The British Red Cross advises gently shaking the person's shoulders and shouting for a response, then tilting the head back and checking whether the chest is moving and breathing can be seen, heard or felt. If there is no normal breathing, call the emergency number immediately and start chest compressions.

1. Call the emergency number (999 or 112 in the UK, or the local equivalent) before starting compressions, St John Ambulance says.
2. Kneel beside the person and place the heel of one hand in the middle of the chest, with the other hand on top and fingers interlocked, per St John Ambulance guidance.
3. Push straight down with arms locked, delivering compressions quickly and firmly. St John Ambulance specifies a rate of 100 to 120 compressions per minute and a depth of about 5 to 6 centimetres, followed by full chest recoil.
4. If trained, give 30 compressions followed by two rescue breaths. St John Ambulance states that a rescuer who cannot or does not want to give breaths should instead give continuous chest compressions.
5. Send someone to fetch an AED but do not leave the person to search for one yourself, St John Ambulance advises. Continue compressions until the person shows signs of life, emergency help arrives, an AED is ready, or you are too exhausted to continue.

Using a defibrillator (AED)

When an AED arrives, open it and follow its voice prompts, the British Red Cross says. The device analyses the heart's rhythm itself and will only deliver a shock if one is needed; if the heart has not restarted, it will give further instructions. Pads should not be used on infants under one year old, and paediatric pads are recommended for children aged one to eight if available.

Choking: clearing a blocked airway

The British Red Cross describes severe choking as a person who clutches at their chest or neck and cannot speak, cough or breathe. If the person can still cough, they should be encouraged to keep coughing, since this may clear the blockage on its own.

1. If coughing does not clear the obstruction, lean the person forward and give up to five firm back blows between the shoulder blades with the heel of your hand, the British Red Cross advises.
2. If the blockage remains, stand behind the person, place a fist just above the navel, and give up to five abdominal thrusts, pulling sharply inward and upward.
3. Keep alternating five back blows and five abdominal thrusts until the object is dislodged or the person starts breathing or coughing normally.
4. Call the emergency number if the choking continues. If the person becomes unresponsive, start CPR, the British Red Cross says.

Severe bleeding: stopping blood loss

For heavy bleeding, the British Red Cross says the priority is to press on the wound with whatever material is available, since pressure helps blood clot. St John Ambulance adds that rescuers should wear protective gloves if available and should not remove any object embedded in the wound, instead applying pressure around it.

1. Apply firm, direct pressure to the wound with a sterile dressing or clean cloth, St John Ambulance advises.
2. Ask someone to call the emergency number, or call yourself, the British Red Cross says.
3. Secure the dressing firmly with a bandage, not so tight that it cuts off circulation; St John Ambulance recommends checking circulation beyond the bandage by pressing a nail until it pales and confirming colour returns within about two seconds.
4. If blood soaks through the dressing, remove it and apply a fresh dressing while keeping up firm pressure, both the British Red Cross and St John Ambulance advise.
5. If the person looks pale, feels cold or dizzy — signs of shock — lay them down and raise their legs above heart level, keeping them warm, both organisations advise.

Stroke: the FAST test

The British Red Cross recommends the FAST test to recognise a possible stroke: Face — is there weakness or drooping on one side of the face; Arms — can the person raise both arms and keep them up; Speech — is their speech clear and understood; Time — call the emergency number straight away if any of these signs are present.

• Other possible signs include dribbling from the mouth, numbness, blurred vision, a severe headache, dizziness or problems with balance, the British Red Cross notes.
• Once the emergency number has been called, help the person sit or lie down, stay with them, and reassure them that help is coming.
• The British Red Cross states that the faster a person having a stroke receives medical help, the less damage is likely to occur.

These steps summarise guidance published by the British Red Cross and St John Ambulance for bystanders without medical training. Both organisations also offer hands-on courses that let people practise the techniques on manikins, which written instructions cannot fully replace.