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Why 30 compressions instead of 15? – the evolution of CPR

Over 30,000 people in the UK experience sudden cardiac arrest in the community every year. In the United States the figure is 383,000. Many are not aware of having heart disease and may not have any of the associated risk factors.

In the UK, fewer than 10% of people on whom a resuscitation attempt is made outside hospital, survive. A British Heart Foundation survey from 2015, conducted by the University of Warwick, highlighted that fewer than half of bystanders would attempt potentially-life-saving cardiopulmonary resuscitation (CPR). Only 37% of respondents reported that they would feel “confident” to deliver immediate CPR. This is of vital importance, as every minute without CPR or defibrillation can reduce the chance of survival by around 10% - after 10 minutes of no intervention the patient only has around a 2% chance of survival. Normally, the heart pumps oxygenated blood to the brain and other vital organs with relentless stability and reliability. However, without oxygen, the brain’s cells go into a state of shock and begin to die within minutes. The UK Resuscitation Council guidelines suggest that immediate bystander CPR can double or quadruple survival from out-of-hospital cardiac arrest. (see also Hasselqvist-Ax et al. 2015, N Engl J Med).

One of the biggest changes in the guidelines – implemented in 2005 – was to move from 15 compressions/2 breaths (15:2) to 30:2. The intention was to increase the number of chest compressions delivered per minute and reduce interruptions in chest compressions. Generally speaking, interruptions in chest compressions are harmful; no blood is pushed forwards. However, maintaining good compression technique is just as important as the sheer number of compressions alone. It is vital to let the chest recoil fully (which helps to refill the heart), not perform compressions too quickly (as this gives insufficient time for the heart to refill; try to maintain 100-120 per minute) and push down far enough on the chest (at least 2 inches). Another key change was that lay bystanders now no longer needed to look for signs of circulation before starting chest compressions.

Some first aid groups recommend performing hands-only CPR, as it can be just as effective as conventional CPR with breaths. One study reported that compression-only CPR (supported by telephone instructions) increased the proportion of patients who survived to hospital discharge. There is also some evidence to suggest that bystanders are more likely to engage in CPR if they do not have to give rescue breaths. This advice is now given as standard by organisations like the British Heart Foundation in their ‘Hard & Fast hands-only CPR’ strategy. The recommended first actions of CPR are also different to what was recommended previously. Nowadays it is preferable to perform chest compressions first, not rescue breaths (AFTER assessing that the patient is unresponsive and not breathing).

There is evidence that some patients can recover – pretty much fully – after long periods in which their heart was in a state of arrest (although this is most likely the exception, rather than the rule). A notable example is the case of ex-professional footballer Fabrice Muamba, who in 2012 collapsed on-field and was, in effect, “dead” for 78 minutes before his heart was restarted. One of the key advantages was having so many qualified, trained first aiders on-site, who could start to deliver good quality CPR straight away whilst getting an automated external defibrillator (AED) ready. It’s important to note that CPR on its own will not return an arrested heart to normal ‘sinus’ rhythm – essentially CPR buys time to access and apply the AED. It is the AED that acts like a ‘reset’ button, trying to ‘shock’ the heart out of its irregular, chaotic pattern of electrical activity. Muamba received some 15 AED shocks in total; three at the football stadium and 12 in the ambulance. It demonstrates the importance of acting FAST.

The current methods of CPR will likely change again in the future, as this is an active area of research. Having the knowledge and the skills to save a life is a valuable contribution to community resilience. If you want to refresh your memory on CPR then the British Heart Foundation is a good place to start. In addition, the European Resuscitation Council promote ‘World Restart a Heart Day’ on the 16th of October every year. The sole purpose of this campaign is to create awareness that everyone and anyone can learn CPR. It is OUR responsibility to learn this life saving skill and share it with others.

So, get some accredited training, choose your favourite up-tempo song to do CPR to, and be READY. Our personal favourite is ‘500 miles’ by Scottish band The Proclaimers. Some others may like Baby Shark!

*This blog does not constitute accredited training guidance on how best to perform CPR.


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