| |||||||||||||||||||||||||||||||
|
|
Bystanders who have been trained in Basic Life Support (BLS) and who witness a sudden collapse in an adult should immediately initiate rescue actions by providing 30 chest compressions of adequate force and depth at a rate of 100 per minute followed by two mouth-to-mouth ventilations. The rescuer(s) should ensure that ventilations cause minimum interruption of chest compressions. At the same time, other bystanders should alert the Emergency Medical Services. This sequence of chest compressions and ventilations should be continued until professional help arrives. For lay rescuers who have not been trained in BLS, or who are not willing or unable to give mouth-to-mouth ventilations, an acceptable alternative is to give uninterrupted chest compressions at a rate of 100/minute. For those rescuers without BLS training and who receive telephone instructions for BLS, the preferred instruction is to give uninterrupted chest compressions until professional help arrives. |
Children should be treated exactly as indicated by the existing paediatric basic life support guidelines.
The evidence for and against the use of compression-only CPR instead of conventional CPR
is being fully evaluated in preparation for the 2010 Consensus Conference on CPR Science.
The evidence available to date is insufficient to warrant a change in guidelines before 2010.
The factors that have been taken into consideration when making this decision are summarised in the table below.
|
In favour of compression-only CPR |
Against compression-only CPR |
| Many animal cardiac arrest studies have shown no survival benefit with the addition of ventilation.2-7 |
In these studies, animals’ airways are generally patent, which may enable chest compressions alone
to generate some ventilation. Pigs continue frequent gasping during good quality CPR and this provides
significant ventilation.8 Unconscious humans in the supine position will generally have an obstructed airway
(unless the airway is supported) and prolonged gasping is less common (7.1% in a recent study9).
A study using an animal model incorporating an obstructed airway demonstrated rapid and profound hypoxaemia
with compression-only CPR.10 |
| Several surveys of both laypeople and healthcare professionals have documented a reluctance to perform mouth-to-mouth ventilation, partly because of fears of infection, but also because it is aesthetically unpleasant.11-14 This fear may prevent bystanders making any attempt at CPR. |
One study indicates that laypeople trained in BLS do not perform bystander CPR mainly because of panic;
when interviewed after actual cardiac arrests, only 4 out of 279 (1.4%) CPR trained bystanders
who failed to do CPR indicated that this was because they objected to doing mouth-to-mouth ventilation.15 |
| In comparison with conventional CPR, compression-only CPR is easier to teach and learn.16 Potentially, far more people could be trained in the compression-only technique, which should lead to an increase in the rate of bystander CPR. |
If laypeople are trained in compression-only CPR they will not be capable of providing mouth-to-mouth
ventilation in those cases in which it is clearly essential, e.g. if cardiac arrest is caused by drowning. The AHA statement indicates that the recommendation for compression-only CPR does not apply to unwitnessed cardiac arrest, cardiac arrest in children or cardiac arrest presumed to be of non-cardiac origin. This implies that laypeople must be able to differentiate cardiac from non-cardiac arrest (unproven) and would need to be trained in conventional CPR as well as compression-only CPR. |
| In a study of dispatch-assisted (telephone) CPR, full instructions were more likely to be delivered completely when the ventilation component was omitted, and survival was (non-significantly) higher in the compression-only group.17 |
A controlled trial involving 4400 bystanders, randomised to provide either dispatch-assisted conventional
or compression-only CPR, will finish recruiting this year (personal communication Prof. Maaret Castren).
The results of this trial may help to determine whether compression-only CPR should be adopted more widely. |
| At least five observational studies have shown similar survival rates when bystanders deliver compression-only CPR rather than conventional CPR.9,18-21 In all of these studies, any CPR (rather than none) was associated with a higher survival rate compared with no CPR. |
These observational studies were undertaken before implementation of the 2005 BLS guidelines,
which included a compression-ventilation ratio of 30:2 instead of 15:2. It is feasible that the outcome
after conventional CPR using a 30:2 ratio is much better. Any benefit of compression-only CPR over conventional CPR has usually been seen only when EMS response times are short (< 4 minutes).9 Most EMS response times are significantly longer than this, and ventilation becomes increasingly important as the duration of cardiac arrest increases.20 |
|
A change to compression-only CPR may benefit particularly those patients in cardiac arrest from a cardiac cause:
approximately 65% - 80% of out-of-hospital, EMS-treated cardiac arrests are of
primary cardiac aetiology.9,22 |
Victims of asphyxial cardiac arrest will need early ventilation if they are to have any chance of surviving. This includes children and drowning victims. |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
© Resuscitation Council (UK) 2008 This page last updated: 8 April 2008 |