European Resuscitation Council Guidelines for Resuscitation ... - CPR

If there is more than one rescuer present, another rescuer shouldtake over delivering CPR every 2 min to prevent fatigue. Ensurethat interruption of chest compressions is minimal during thechangeover of rescuers.6b. Chest-compression-only CPR may be used as follows:• if you are not trained, or are unwilling to give rescue breaths,give chest compressions only;• if only chest compressions are given, these should be continuous,at a rate of at least 100 min −1 (but not exceeding 120 min −1 ).7. Do not interrupt resuscitation until:• professional help arrives and takes over; or• the victim starts to wake up: to move, opens eyes and to breathenormally; or• you become exhausted.Recognition of cardiorespiratory arrestChecking the carotid pulse (or any other pulse) is an inaccuratemethod of confirming the presence or absence of circulation,both for lay rescuers and for professionals. 64–66 Healthcare professionals,as well as lay rescuers, have difficulty determining thepresence or absence of adequate or normal breathing in unresponsivevictims. 67,68 This may be because the victim is makingoccasional (agonal) gasps, which occur in the first minutes afteronset in up to 40% of cardiac arrests. 69 Laypeople should be taughtto begin CPR if the victim is unconscious (unresponsive) and notbreathing normally. It should be emphasised during training thatthe presence of agonal gasps is an indication for starting CPR immediately.Initial rescue breathsIn adults needing CPR, the cardiac arrest is likely to have a primarycardiac cause – CPR should start with chest compressionrather than initial ventilations. Time should not be spent checkingthe mouth for foreign bodies unless attempted rescue breathingfails to make the chest rise.VentilationDuring CPR, the optimal tidal volume, respiratory rate andinspired oxygen concentration to achieve adequate oxygenationand CO 2 removal is unknown. During CPR, blood flow to the lungs issubstantially reduced, so an adequate ventilation–perfusion ratiocan be maintained with lower tidal volumes and respiratory ratesthan normal. 70 Hyperventilation is harmful because it increasesintrathoracic pressure, which decreases venous return to the heartand reduces cardiac output. Interruptions in chest compressionreduce survival. 71Rescuers should give each rescue breath over about 1 s, withenough volume to make the victim’s chest rise, but to avoid rapidor forceful breaths. The time taken to give two breaths should notexceed 5 s. These recommendations apply to all forms of ventilationduring CPR, including mouth-to-mouth and bag-mask ventilationwith and without supplementary oxygen.Chest compressionChest compressions generate a small but critical amount ofblood flow to the brain and myocardium and increase the likelihoodthat defibrillation will be successful. Optimal chest compressiontechnique comprises: compressing the chest at a rate of at least100 min −1 and to a depth of at least 5 cm (for an adult), butnot exceeding 6 cm; allowing the chest to recoil completely aftereach compression 72,73 ; taking approximately the same amountof time for compression as relaxation. Rescuers can be assisted18 de 0ctubre de 2010 www.elsuapdetodos.comJ.P. Nolan et al. / Resuscitation 81 (2010) 1219–1276 1225to achieve the recommended compression rate and depth byprompt/feedback devices that are either built into the AED or manualdefibrillator, or are stand-alone devices.Compression-only CPRSome healthcare professionals as well as lay rescuers indicatethat they would be reluctant to perform mouth-to-mouth ventilation,especially in unknown victims of cardiac arrest. 74,75 Animalstudies have shown that chest-compression-only CPR may be aseffective as combined ventilation and compression in the firstfew minutes after non-asphyxial arrest. 76,77 If the airway is open,occasional gasps and passive chest recoil may provide some airexchange, but this may result in ventilation of the dead spaceonly. 69,78–80 Animal and mathematical model studies of chestcompression-onlyCPR have shown that arterial oxygen storesdeplete in 2–4 min. 81,82 In adults, the outcome of chest compressionwithout ventilation is significantly better than the outcome ofgiving no CPR at all in non-asphyxial arrest. 46,47 Several studies ofhuman cardiac arrest suggest equivalence of chest-compressiononlyCPR and chest compressions combined with rescue breaths,but none of these studies exclude the possibility that chestcompression-onlyis inferior to chest compressions combined withventilations. 47,83 Chest compression-only may be sufficient onlyin the first few minutes after collapse. Chest-compression-onlyCPR is not as effective as conventional CPR for cardiac arrests ofnon-cardiac origin (e.g., drowning or suffocation) in adults andchildren. 84,85 Chest compression combined with rescue breaths is,therefore, the method of choice for CPR delivered by both trainedlay rescuers and professionals. Laypeople should be encouraged toperform compression-only CPR if they are unable or unwilling toprovide rescue breaths, or when instructed during an emergencycall to an ambulance dispatcher centre.Risks to the rescuerPhysical effectsThe incidence of adverse effects (muscle strain, back symptoms,shortness of breath, hyperventilation) on the rescuer fromCPR training and actual performance is very low. 86 Several manikinstudies have found that, as a result of rescuer fatigue, chest compressiondepth can decrease as little as 2 min after starting chestcompressions. 87 Rescuers should change about every 2 min to preventa decrease in compression quality due to rescuer fatigue.Changing rescuers should not interrupt chest compressions.www.elsuapdetodos.comRisks during defibrillationA large randomised trial of public access defibrillation showedthat AEDs can be used safely by laypeople and first responders. 88 Asystematic review identified only eight papers that reported a totalof 29 adverse events associated with defibrillation. 89 Only one ofthese adverse events was published after 1997. 90Disease transmissionThere are only very few cases reported where performing CPRhas been linked to disease transmission. Three studies showed thatbarrier devices decreased transmission of bacteria in controlledlaboratory settings. 91,92 Because the risk of disease transmissionis very low, initiating rescue breathing without a barrier deviceis reasonable. If the victim is known to have a serious infectionappropriate precautions are recommended.Recovery positionThere are several variations of the recovery position, each withits own advantages. No single position is perfect for all victims. 93,94The position should be stable, near to a true lateral position with