Saving Broken Hearts
What happens when you suffer a cardiac arrest?
Every year in the UK, more than 30,000 people's hearts stop, as footballer Fabrice Muamba did and they collapse, writes Dr Rob Galloway.
Without treatment, within a few minutes the brain becomes starved of oxygen and the patient dies.
Usually the cause is a malfunction of the hearts electrical circuitry instead of normal, strong contractions, the heart starts to quiver. The key is to keep the patientâ€s body alive while waiting for a defibrillator to shock the heart back into its correct rhythm.
And this means CPR heart massage. Compressing on the chest pushes blood to the brain as well as the muscles of the heart; this keeps the brain alive while â€˜priming the heartâ€ so it has enough blood and oxygen, and is capable of being shocked back into a normal rhythm.
This is the first treatment Fabrice Muamba would have received on the pitch at White Hart Lane after he collapsed. The quicker a defibrillator is used, the greater the chance of survival.
These days some offices, hotels and even shopping centres carry defibrillators for public use these have voice-prompts to tell you what to do at each step.
Once the heart restarts, doctors and paramedics have the problem of keeping the patient alive.
The patient won't be able to breathe on their own because the brain will have been affected and their chest wall muscles won't be working properly. This means a breathing tube is inserted and a life-support machine takes over.
The next thing to do is to cool the brain. The problem is that, even during CPR, the brain is not supplied with as much oxygen as a fully functioning heart would provide.
This lack of oxygen causes the release of free radicals that destroy brain cells, leading to brain damage.
We used to think nothing much could be done about this, and 75per cent of the patients the paramedics brought to hospital alive after a cardiac arrest died soon afterwards.
However, a new treatment cooling the brain down for 24 hours using special ice packs to reduce the temperature of the patient's whole body limits the release of these free radicals and so gives the brain time to repair itself.
As a result, more and more patients survive cardiac arrest with a fully functioning brain.
Dr Rob Galloway is a consultant in accident and emergency and a crowd doctor for Brighton and Hove Albion FC.