What is cardiopulmonary resuscitation (CPR) and how did it save Christian Eriksen's life?
On Saturday, Christian Eriksen suffered a cardiac arrest. The swift intervention of Simon Kjaer and the medical staff saved his life. "[Eriksen] was gone," Denmark's team doctor Morten Boesen said. "We did cardiac resuscitation, it was a cardiac arrest. I don't know but we got him back after one defib, so that's quite fast." Eriksen's sudden collapse prompted Kjaer to clear his team-mate's airways and start the life-saving CPR technique, which was continued with the aid of a defibrillator and professional medical staff. Fortunately, the Denmark captain's first aid skills proved vital and Eriksen is now recovering in hospital and considered to be out of danger. CPR is quite easy to learn and it can be the difference between life and death before emergency medical services can arrive to help out. CPR stands for cardiopulmonary resuscitation and is a medical technique which is given to someone who goes into cardiac arrest. That occurs when the heart encounters an electrical issue and stops pumping blood around the body and to the brain, causing the person to fall out of consciousness and stop breathing. Medics define this as 'clinical death', which is the onset of biological death, although CPR can help re-start the person's heart functions and save their life. By administering chest compressions and rescue breaths, the CPR performer helps to pump blood and oxygen around the person's body, taking over the role of their heart and lungs. 4:10 Dr Sanjay Sharma, a sports cardiologist at St George's Hospital who worked with Christian Eriksen at Tottenham, says the speedy response of the medical team on the field was critical for his recovery  "Time is myocardium, that's what we say in medicine - that means the longer that there is a time delay, the higher the chance that the heart muscle will never recover," Professor of Cardiology Dr Sanjay Sharma told Sky Sports News. "In fact for every minute that passes, the chances of an individual surviving go down by between seven and 10 per cent. So it's very, very crucial to keep the heart beating during these crucial moments and get the heart started as quickly as possible. "Not just so that the cardiac outcome will be good, but also that the other organs, such as the brain, remain well perfused so that the individual after survival remains healthy." 2:46 Fabrice Muamba says Christian Eriksen's health and wellbeing is the most important thing, after the Denmark midfielder suffered a cardiac arrest  Always seek professional help by calling 999 before starting CPR. The NHS's advice to carry out chest compressions is as follows:  Place the heel of your hand on the breastbone at the centre of the person's chest. Place your other hand on top of your first hand and interlock your fingers. Position yourself with your shoulders above your hands. Using your body weight (not just your arms), press straight down by 5 to 6cm (2 to 2.5 inches) on their chest. Keeping your hands on their chest, release the compression and allow the chest to return to its original position. Repeat these compressions at a rate of 100 to 120 times a minute until an ambulance arrives or you become exhausted. The British Heart Foundation recommends that in an emergency situation it is better to try and perform CPR, even if unsure, rather than to not do anything at all. Muamba's doctor relieved by Eriksen's recovery  1:29 Dr Andrew Deaner, who treated Fabrice Muamba when he suffered a cardiac arrest nine years ago, praised the speedy medical response after Christian Eriksen collapsed  Dr Andrew Deaner, who treated Fabrice Muamba when he suffered a cardiac arrest nine years ago, praised the speedy medical response after Christian Eriksen collapsed. "In many ways, Christian has reacted to CPR and defibrillation in the way we would have expected Fabrice to," he told Sky Sports News. "We were obviously really disappointed and surprised that Fabrice didn't come around so quickly, fortunately by continuing CPR and other advanced resuscitation efforts we managed to save Fabrice, but after being unconscious for a much longer time. "The norm is what happened with Christian, that if CPR is started effectively you have early access to defibrillators and get a positive result. "I think it's just another example that everybody should recognise the importance of early CPR, learn how to do CPR and make sure that you have defibrillators available quickly." For more information on FA medical courses which can help to deal with such things as cardiac arrest and how to treat them, visit the FA Bootroom.