Clinical Review
Forum
Cardiac arrest – CPR
guidelines simplified
New CPR guidelines, which stress the importance of immediate
chest compressions, were recently issued, writes Seamus Clarke
A cardiac arrest is defined as the sudden abrupt loss of
heart function and is the terminal event in sudden cardiac
death.1 According to the recently published cardiovascular
strategy from the Department of Health, there are approximately 5,000 sudden cardiac deaths each year in Ireland.
That equates to approximately 14 deaths per day. Some
75% of these sudden collapses happen in the pre-hospital
environment.2 Of these, about 100 are under the age of 35.
The causes of sudden cardiac death are varied, such as
coronary artery disease, cardiomyopathy and arrhythmias.
The European Task Force on Sudden Cardiac Death has
recommended a time limit of five minutes from a cardiac
arrest to defibrillation in a community setting. Currently,
those suffering from a cardiac arrest have a 5-10% chance
of surviving to a hospital discharge.
The key to successful resuscitation lies in effective cardiopulmonary resuscitation (CPR) until defibrillation can occur.
The chance of survival reduces by 10% by each minute
that CPR and defibrillation are delayed. Indeed, early CPR
and defibrillation within two minutes of a cardiac arrest can
lead to survival rates of over 60%. GPs will experience cardiac arrests on an occasional basis but it is important that
they are familiar with the current international guidelines
on CPR to optimise this chance of survival.
The International Liaison Committee on Resuscitation
(ILCOR) was set up in 1992 to establish a consensus between
the major international resuscitation organisations on CPR
guidelines based on the latest scientific evidence. The last
meeting of ILCOR was in October 2010 at which new CPR
guidelines were announced.4 The previous guidelines were
issued in 2005. These have been endorsed by the European
Resuscitation Council for adoption and it is expected that
they will be implemented nationally in the coming months.
The changes on this occasion are certainly not as drastic as
the 2005 guidelines. In this article we will review the main
changes in the basic life support (BLS) and give a brief summary of the changes and the science behind the changes.
A huge emphasis is now placed on the importance of
bystander CPR and encouraging bystanders to respond
even if they have never been trained in CPR. On making
a 999/112 call, callers are now encouraged by the control
room call-taker to perform compression-only CPR. This is to
ensure that all victims receive early compressions.
It is worth noting that attending a class and practising
CPR improves performance during a cardiac arrest and
would certainly put these new changes into context.
Compressions
The 2010 guidelines continue to put emphasis on high
Practising CPR improves
performance
quality CPR and uninterrupted chest compressions. This
can be achieved by a:
• Compression rate of at least 100/min (which has increased
since 2005)
• Compression depth of at least 5cm (two inches) in adults,
in children approx 5cm (two inches) and in infants approx
4cm (1.5 inches). These depths are deeper than 2005
depths
• Allow complete chest recoil
• Minimise interruptions in chest compressions; in other
words the less time spent with hands off the chest, the
better the chance of a favourable outcome for the victim.
Research has shown that the only people who survive
cardiac arrest are those who have had early chest compressions. Compressions create blood flow and oxygen
delivery to the heart, brain and vital organs by increasing
intrathoracic pressure and compressing the heart directly.
If compressions are not deep enough this will result in inadequate blood flow and oxygenation. Compressions need to
be uninterrupted. If compressions are interrupted for a
period of 10 seconds blood flow is adversely affected and a
long period of chest compressions will be then required to
return an adequate cardiac output.
Ventilations
The ratio of compressions to ventilations remains at 30:2
in adult, infant and child. There are no changes in the following but it is worth recapping them:
• Avoid excessive ventilations
• Breaths should be given over one second each
• Rescue breaths are given at one breath every five to six
seconds
• Do not over-ventilate the victim.
Once again, ventilations are being de-emphasised. One of
the big changes is the elimination of ‘look listen and feel’.
The reason for this is that many rescuers find it difficult to
recognise adequate breathing and they spend a long period
of time checking for breathing and therefore delaying chest
FORUM April 2011 53
CPR/JMC/NH2/SS 1
25/03/2011 15:35:52
compressions. Agonal breathing is often mistaken for adequate breathing. We will discuss the new CAB sequence
below. Responders now briefly check for breathing as they
are checking for a response and pulse while shouting for
help. Basically, all of the initial steps have been put together
while adding to the speed of commencing compressions.
Change of sequence from ABC to CAB
One of the biggest changes in the 2010 guidelines is
the change from ABC to CAB. Therefore, instead of airway,
breathing and circulation we will now do compressions,
airway, breathing. This change was brought about because
of the importance of early chest compressions. It was found
that compressions are regularly delayed by responders being
slow to recognise cardiac arrest, confusing agonal breathing
with normal breathing and delaying while assembling face
masks and other devices. Agonal breathing is a shallow and
slow breathing pattern which is often irregular in nature
and provides no effective oxygenation.
On finding a collapsed victim, the new sequence is:
• Check for responsiveness. While checking this, scan the
chest for no breathing or no normal breathing (‘head tilt’,
‘chin lift’, and ‘look listen and feel’ are gone). While checking for breathing also check the pulse simultaneously
• Call for an automated external defibrillator (AED)/defibrillator and call emergency services on 999 or 112
• Start chest compressions
• Continue compressions and breaths at a ratio of 30:2
• When AED arrives, attach it with minimal interruptions.
AED use
The AED should be attached to the victim as soon as it
arrives on scene. There should be minimal interruptions in
chest compressions while attaching the pads. A new recommendation is the use of AEDs on infants. In the 2005
guidelines it was recommended that AEDs could be used
on children but this recommendation has now been further
extended to include infants. It is preferable to use child
AED pads but if these are not available, adult pads can be
used. Remember, two minutes of CPR are performed on
children and infants prior to attaching the AED except in a
sudden collapse, when it should be attached immediately.
Chain of survival
• Immediate recognition of cardiac arrest and activation of
the emergency response system
• Early CPR with an emphasis on chest compressions
• Rapid defibrillation
• Effective advanced life support
• Integrated post-cardiac arrest care.
A fifth link has been added to the chain of survival,
emphasising the importance of post-cardiac arrest care:
Early CPR
In summary, the guidelines have been further simplified to ensure that those in cardiac arrest are quickly
identified as being in cardiac arrest and that they
receive high quality uninterrupted CPR and defibrillation
early. To read more on the new guidelines, read Circulation, November 2010 edition. For CPR classes go to
www.irishheart.ie/resus and click onto affiliated training sites
for course providers. For information, see www.phecc.ie
Seamus Clarke is a GP in Co Monaghan
Acknowledgements: Brian Carlin, lecturer in emergency medicine, UCD
CPR/JMC/NH2/SS 2
25/03/2011 15:36:01