Resuscitation 95 (2015) 81–99 Contents lists available at ScienceDirect Resuscitation journal homepage: www.elsevier.com/locate/resuscitation European Resuscitation Council Guidelines for Resuscitation 2015 Section 2. Adult basic life support and automated external defibrillation Gavin D. Perkinsa,b,∗ , Anthony J. Handleyc , Rudolph W. Kosterd , Maaret Castréne , Michael A. Smytha,f , Theresa Olasveengeng , Koenraad G. Monsieursh,i , Violetta Raffayj , Jan-Thorsten Gräsnerk , Volker Wenzell , Giuseppe Ristagnom , Jasmeet Soarn , on behalf of the Adult basic life support and automated external defibrillation section Collaborators1 a Warwick Medical School, University of Warwick, Coventry, UK b Critical Care Unit, Heart of England NHS Foundation Trust, Birmingham, UK c Hadstock, Cambridge, UK d Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands e Department of Emergency Medicine and Services, Helsinki University Hospital and Helsinki University, Finland f West Midlands Ambulance Service NHS Foundation Trust, Dudley, UK g Norwegian National Advisory Unit on Prehospital Emergency Medicine and Department of Anesthesiology, Oslo University Hospital, Oslo, Norway h Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium i Faculty of Medicine and Health Sciences, University of Ghent, Ghent, Belgium j Municipal Institute for Emergency Medicine Novi Sad, Novi Sad, Serbia k Department of Anaesthesia and Intensive Care Medicine, University Medical Center Schleswig-Holstein, Kiel, Germany l Department of Anesthesiology and Critical Care Medicine, Medical University of Innsbruck, Innsbruck, Austria m Department of Cardiovascular Research, IRCCS-Istituto di Ricerche Farmacologiche “Mario Negri”, Milan, Italy n Anaesthesia and Intensive Care Medicine, Southmead Hospital, Bristol, UK Introduction This chapter contains guidance on the techniques used during the initial resuscitation of an adult cardiac arrest victim. This includes basic life support (BLS: airway, breathing and circulation support without the use of equipment other than a protective device) and the use of an automated external defibrillator (AED). Simple techniques used in the management of choking (foreign body airway obstruction) are also included. Guidelines for the use of manual defibrillators and starting in-hospital resuscitation are found in the section Advanced Life Support Chapter.1 A summary of the recovery position is included, with further information provided in the First Aid Chapter.2 The guidelines are based on the ILCOR 2015 Consensus on Science and Treatment Recommendations (CoSTR) for BLS/AED.3 The ILCOR review focused on 23 key topics leading to 32 treatment recommendations in the domains of early access and cardiac arrest prevention, early, high-quality CPR, and early defibrillation. For these ERC guidelines the ILCOR recommendations were supplemented by focused literature reviews undertaken by Writing Group members in areas not reviewed by ILCOR. The writing group were ∗ Corresponding author. E-mail address: g.d.perkins@warwick.ac.uk (G.D. Perkins). 1 The members of the Adult basic life support and automated external defibrillation section Collaborators are listed in the Collaborators section. cognisant of the costs and potential confusion created by changing guidance from 2010, and therefore sought to limit changes to those judged to be essential and supported by new evidence. Guidelines were drafted by Writing Group members, then reviewed by the full writing group and national resuscitation councils before final approval by the ERC Board. Summary of changes since the ERC 2010 guidelines Guidelines 2015 highlights the critical importance of the interactions between the emergency medical dispatcher, the bystander who provides CPR and the timely deployment of an automated external defibrillator. An effective, co-ordinated community response that draws these elements together is key to improving survival from out-of-hospital cardiac arrest (Fig. 2.1). The emergency medical dispatcher plays an important role in the early diagnosis of cardiac arrest, the provision of dispatcherassisted CPR (also known as telephone CPR), and the location and dispatch of an automated external defibrillator. The sooner the emergency services are called, the earlier appropriate treatment can be initiated and supported. The knowledge, skills and confidence of bystanders will vary according to the circumstances, of the arrest, level of training and prior experience. The ERC recommends that the bystander who is trained and able should assess the collapsed victim rapidly to determine if the victim http://dx.doi.org/10.1016/j.resuscitation.2015.07.015 0300-9572/© 2015 European Resuscitation Council. Published by Elsevier Ireland Ltd. All rights reserved. 82 G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 COMMUNITY RESPONSE SAVES LIVES 112 Fig. 2.1. The interactions between the emergency medical dispatcher, the bystander who provides CPR and the timely use of an automated external defibrillator are the key ingredients for improving survival from out of hospital cardiac arrest. is unresponsive and not breathing normally and then immediately alert the emergency services. Whenever possible, alert the emergency services without leaving the victim. The victim who is unresponsive and not breathing normally is in cardiac arrest and requires CPR. Immediately following cardiac arrest blood flow to the brain is reduced to virtually zero, which may cause seizure-like episodes that may be confused with epilepsy. Bystanders and emergency medical dispatchers should be suspicious of cardiac arrest in any patient presenting with seizures and carefully assess whether the victim is breathing normally. The writing group endorses the ILCOR recommendation that all CPR providers should perform chest compressions for all victims in cardiac arrest. CPR providers trained and able to perform rescue breaths should combine chest compressions and rescue breaths. The addition of rescue breaths may provide additional benefit for children, for those who sustain an asphyxial cardiac arrest, or where the emergency medical service (EMS) response interval is prolonged. Our confidence in the equivalence between chest compression-only and standard CPR is not sufficient to change current practice. High quality cardiopulmonary resuscitation remains essential to improving outcomes. The ERC 2015 guideline for chest compression depth is the same as the 2010 guideline. CPR providers should ensure chest compressions of adequate depth (at least 5 cm but not more than 6 cm) with a rate of 100–120 compressions per minute. Allow the chest to recoil completely after each compression and minimise interruptions in compressions. When providing rescue breaths/ventilations spend approximately 1 s inflating the chest with sufficient volume to ensure the chest rises visibly. The ratio of chest compressions to ventilations remains 30:2. Do not interrupt chest compressions for more than 10 s to provide ventilations. Defibrillation within 3–5 min of collapse can produce survival rates as high as 50–70%. Early defibrillation can be achieved through CPR providers using public access and on-site AEDs. Public access AED programmes should be actively implemented in public places that have a high density of citizens, such as airports, railway stations, bus terminals, sport facilities, shopping malls, offices and casinos. It is here that cardiac arrests are often witnessed, and trained CPR providers can be on-scene quickly. Placing AEDs in areas where one cardiac arrest per 5 years can be expected is considered cost-effective, and the cost per added life-year is comparable to other medical interventions. Past experience of the number of cardiac arrests in a certain area, as well as the neighbourhood characteristics, may help guide AED placement. Registration of public access AEDs allows dispatchers to direct CPR providers to a nearby AED and may help to optimise response. The adult CPR sequence can be used safely in children who are unresponsive and not breathing normally. For CPR providers with additional training a modified sequence which includes providing 5 initial rescue breaths before starting chest compressions and delaying going for help in the unlikely situation that the rescuer is alone is even more suitable for the child and drowning victim. Chest compression depths in children should be at least one third of the depth of the chest (for infants that is 4 cm, for children 5 cm). A foreign body causing severe airway obstruction is a medical emergency. It almost always occurs whilst the victim is eating or drinking and requires prompt treatment. Start by encouraging the victim to cough. If the victim has severe airway obstruction or begins to tire, give back blows and, if that fails to relieve the obstruction, abdominal thrusts. If the victim becomes unresponsive, start CPR immediately whilst help is summoned. Cardiac arrest Sudden cardiac arrest (SCA) is one of the leading causes of death in Europe. Depending how SCA is defined, about 55–113 per 100,000 inhabitants a year or 350,000–700,000 individuals a year are affected in Europe.4–6 On initial heart-rhythm analysis, about 25–50% of SCA victims have ventricular fibrillation (VF), a percentage that has declined over the last 20 years.7–13 It is likely that many more victims have VF or rapid ventricular tachycardia (VT) at the time of collapse, but by the time the first electrocardiogram (ECG) is recorded by emergency medical service personnel their rhythm has deteriorated to asystole.14,15 When the rhythm is recorded soon after collapse, in particular by an on-site AED, the proportion of victims in VF can be as high as 76%.16,17 More victims of SCA survive if bystanders act immediately while VF is still present. Successful resuscitation is less likely once the rhythm has deteriorated to asystole. The recommended treatment for VF cardiac arrest is immediate bystander CPR and early electrical defibrillation. Most cardiac arrests of non-cardiac origin have respiratory causes, such as drowning (among them many children) and asphyxia. Rescue breaths as well as chest compressions are critical for successful resuscitation of these victims. The chain of survival The Chain of Survival summarises the vital links needed for successful resuscitation (Fig. 2.2). Most of these links apply to victims of both primary cardiac and asphyxial arrest.18 Early recognition and call for help Chest pain should be recognised as a symptom of myocardial ischaemia. Cardiac arrest occurs in a quarter to a third of patients with myocardial ischaemia within the first hour after onset of chest pain.19 Recognising the cardiac origin of chest pain, and calling the emergency services before a victim collapses, enables the emergency medical service to arrive sooner, hopefully before cardiac arrest has occurred, thus leading to better survival.20–23 Once cardiac arrest has occurred, early recognition is critical to enable rapid activation of the EMS and prompt initiation of bystander CPR. The key observations are unresponsiveness and not breathing normally. Emergency medical dispatchers can improve recognition by focusing on these keywords. G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 83 Fig. 2.2. The chain of survival. Early bystander CPR The immediate initiation of CPR can double or quadruple survival from cardiac arrest.20,24–28 If able, bystanders with CPR training should give chest compressions together with ventilations. When a bystander has not been trained in CPR, the emergency medical dispatcher should instruct him or her to give chestcompression-only CPR while awaiting the arrival of professional help.29–31 Early defibrillation Defibrillation within 3–5 min of collapse can produce survival rates as high as 50–70%. This can be achieved by public access and onsite AEDs.13,17,32,33 Each minute of delay to defibrillation reduces the probability of survival to discharge by 10–12%. The links in the chain work better together: when bystander CPR is provided, the decline in survival is more gradual and averages 3–4% per minute delay to defibrillation.20,24,34 Early advanced life support and standardised post-resuscitation care Advanced life support with airway management, drugs and correcting causal factors may be needed if initial attempts at resuscitation are un-successful. The quality of treatment during the post-resuscitation phase affects outcome and are addressed in the adult advanced life support and post resuscitation care chapters.1,35 The critical need for bystanders to act In most communities, the median time from emergency call to emergency medical service arrival (response interval) is 5–8 min,16,36–38 or 8–11 min to a first shock.13,27 During this time the victim’s survival depends on bystanders who initiate CPR and use an automated external defibrillator (AED). Victims of cardiac arrest need immediate CPR. This provides a small but critical blood flow to the heart and brain. It also increases the likelihood that the heart will resume an effective rhythm and pumping power. Chest compressions are especially important if a shock cannot be delivered within the first few minutes after collapse.39 After defibrillation, if the heart is still viable, its pacemaker activity resumes and produces an organised rhythm followed by mechanical contraction. In the first minutes after termination of VF, the heart rhythm may be slow, and the force of contractions weak; chest compressions must be continued until adequate cardiac function returns. Use of an AED by lay CPR providers increases survival from cardiac arrest in public places.16 AED use in residential areas is also increasing.40 An AED uses voice prompts to guide the CPR provider, analyse the cardiac rhythm and instruct the CPR provider to deliver a shock if VF or rapid ventricular tachycardia (VT) is detected. They are accurate and will deliver a shock only when VF (or rapid VT) is present.41,42 Recognition of cardiac arrest Recognising cardiac arrest can be challenging. Both bystanders and emergency call handlers (emergency medical dispatchers) have to diagnose cardiac arrest promptly in order to activate the chain of survival. Checking the carotid pulse (or any other pulse) has proved to be an inaccurate method for confirming the presence or absence of circulation.43–47 Agonal breaths are slow and deep breaths, frequently with a characteristic snoring sound. They originate from the brain stem, the part of the brain that remains functioning for some minutes even when deprived of oxygen. The presence of agonal breathing can be erroneously interpreted as evidence that there is a circulation and CPR is not needed. Agonal breathing may be present in up to 40% of victims in the first minutes after cardiac arrest, and if responded to as a sign of cardiac arrest, is associated with higher survival rates.48 The significance of agonal breathing should be emphasised during basic life support training.49,50 Bystanders should suspect cardiac arrest and start CPR if the victim is unresponsive and not breathing normally. Immediately following cardiac arrest, blood flow to the brain is reduced to virtually zero, which may cause seizure-like episodes that can be confused with epilepsy. Bystanders should be suspicious of cardiac arrest in any patient presenting with seizures.51,52 Although bystanders who have witnessed cardiac arrest events report changes in the victims’ skin colour, notably pallor and bluish changes associated with cyanosis, these changes are not diagnostic of cardiac arrest.51 Role of the emergency medical dispatcher The emergency medical dispatcher plays a critical role in the diagnosis of cardiac arrest, the provision of dispatcher assisted CPR (also known as telephone CPR), the location and dispatch of an automated external defibrillator and dispatch of a high priority EMS response. The sooner the emergency services are called, the earlier appropriate treatment can be initiated and supported. Dispatcher recognition of cardiac arrest Confirmation of cardiac arrest, at the earliest opportunity is critical. If the dispatcher recognises cardiac arrest, survival is more likely because appropriate measures can be taken.53,54 84 G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 Enhancing dispatcher ability to identify cardiac arrest, and optimising emergency medical dispatcher processes, may be cost-effective solutions to improve outcomes from cardiac arrest. Use of scripted dispatch protocols within emergency medical communication centres, including specific questions to improve cardiac arrest recognition may be helpful. Patients who are unresponsive and not breathing normally should be presumed to be in cardiac arrest. Adherence to such protocols may help improve cardiac arrest recognition,9,55–57 whereas failure to adhere to protocols reduces rates of cardiac arrest recognition by dispatchers as well as the provision of telephone-CPR.58–60 Obtaining an accurate description of the victim’s breathing pattern is challenging for dispatchers. Agonal breathing is often present, and callers may mistakenly believe the victim is still breathing normally.9,60–68 Offering dispatchers additional education, specifically addressing the identification and significance of agonal breathing, can improve cardiac arrest recognition, increase the provision of telephone-CPR,67,68 and reduce the number of missed cardiac arrest cases.64 Asking questions regarding the regularity or pattern of breathing may help improve recognition of abnormal breathing and thus identification of cardiac arrest. If the initial emergency call is for a person suffering seizures, the call taker should be highly suspicious of cardiac arrest, even if the caller reports that the victim has a prior history of epilepsy.61,69 Dispatcher assisted CPR Bystander CPR rates are low in many communities. Dispatcherassisted CPR (telephone-CPR) instructions have been demonstrated to improve bystander CPR rates,9,56,70–72 reduce the time to first CPR,56,57,68,72,73 increase the number of chest compressions delivered70 and improve patient outcomes following out-ofhospital cardiac arrest (OHCA) in all patient groups.9,29–31,57,71,74 Dispatchers should provide telephone-CPR instructions in all cases of suspected cardiac arrest unless a trained provider is already delivering CPR. Where instructions are required for an adult victim, dispatchers should provide chest-compression-only CPR instruc- tions. If the victim is a child, dispatchers should instruct callers to provide both ventilations and chest compressions. Dispatchers should therefore be trained to provide instructions for both tech- niques. Adult BLS sequence The sequence of steps for the initial assessment and treatment of the unresponsive victim are summarised in Fig. 2.3. The sequence of steps takes the reader through recognition of cardiac arrest, calling EMS, starting CPR and using an AED. The number of steps has been reduced to focus on the key actions. The intent of the revised algorithm is to present the steps in a logical and concise manner that is easy for all types of rescuers to learn, remember and perform. Fig. 2.4 presents the detailed step-by-step sequence for the trained provider. It continues to highlight the importance of ensuring rescuer, victim and bystander safety. Calling for additional help (if required) is incorporated in the alerting emergency services step below. For clarity the algorithm is presented as a linear sequence of steps. It is recognised that the early steps of checking response, opening the airway, checking for breathing and calling the emergency medical dispatcher may be accomplished simultaneously or in rapid succession. Those who are not trained to recognise cardiac arrest and start CPR would not be aware of these guidelines and therefore require dispatcher assistance whenever they make the decision Unresponsive and not breathing normally Call Emergency Services Give 30 chest compressions Give 2 rescue breaths Continue CPR 30:2 As soon as AED arrives - switch it on and follow instructions Fig. 2.3. The BLS/AED Algorithm. to call 112. These guidelines do not therefore include specific recommendations for those who are not trained to recognise cardiac arrest and start CPR. The remainder of this section provides supplemental information on some of the key steps within the overall sequence. Opening the airway and checking for breathing The trained provider should assess the collapsed victim rapidly to determine if they are responsive and breathing normally. Open the airway using the head tilt and chin lift technique whilst assessing whether the person is breathing normally. Do not delay assessment by checking for obstructions in the airway. The jaw thrust and finger sweep are no longer recommended for the lay provider. Check for breathing using the techniques described in Fig. 2.4 noting the critical importance of recognising agonal breathing described above. Alerting emergency services 112 is the European emergency phone number, available everywhere in the EU, free of charge. It is possible to call 112 from fixed and mobile phones to contact any emergency service: an ambulance, the fire brigade or the police. Some European countries provide an alternative direct access number to emergency medical services, which may save time. Bystanders should therefore follow national guidelines on the optimal phone number to use. Early contact with the emergency services will facilitate dispatcher assistance in the recognition of cardiac arrest, telephone instruction on how to perform CPR, emergency medical service/first responder dispatch, and on locating and dispatching of an AED.75–78 If possible, stay with the victim while calling the emergency services. If the phone has a speaker facility switch it to speaker as this will facilitate continuous dialogue with the dispatcher including (if required) CPR instructions.79 It seems reasonable that CPR G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 85 Fig. 2.4. Step by step sequence of actions for use by the BLS/AED trained provider to treat the adult cardiac arrest victim. 86 G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 Fig. 2.4. (Continued ). G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 87 Fig. 2.4. (Continued ). 88 G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 Fig. 2.4. (Continued ). training should include how to activate the speaker phone.80 Additional bystanders may be used to help call the emergency services. Starting chest compressions In adults needing CPR, there is a high probability of a primary cardiac cause. When blood flow stops after cardiac arrest, the blood in the lungs and arterial system remains oxygenated for some minutes. To emphasise the priority of chest compressions, it is recommended that CPR should start with chest compressions rather than initial ventilations. Manikin studies indicate that this is associated with a shorter time to commencement of CPR.81–84 When providing manual chest compressions: 1. Deliver compressions ‘in the centre of the chest’. 2. Compress to a depth of at least 5 cm but not more than 6 cm. 3. Compress the chest at a rate of 100–120 min−1 with as few interruptions as possible. 4. Allow the chest to recoil completely after each compression; do not lean on the chest. Hand position Experimental studies show better haemodynamic responses when chest compressions are performed on the lower half of the sternum.85–87 It is recommended that this location be taught in a simplified way, such as, “place the heel of your hand in the centre of the chest with the other hand on top”. This instruction should be accompanied by a demonstration of placing the hands on the lower half of the sternum.88,89 Chest compressions are most easily delivered by a single CPR provider kneeling by the side of the victim, as this facilitates movement between compressions and ventilations with minimal interruptions. Over-the-head CPR for single CPR providers and straddle-CPR for two CPR providers may be considered when it is not possible to perform compressions from the side, for example when the victim is in a confined space.90,91 Compression depth Fear of doing harm, fatigue and limited muscle strength frequently result in CPR providers compressing the chest less deeply than recommended. Four observational studies, published after the 2010 Guidelines, suggest that a compression depth range of 4.5–5.5 cm in adults leads to better outcomes than all other compression depths during manual CPR.92–95 Based on an analysis of 9136 patients, compression depths between 40 and 55 mm with a peak at 46 mm, were associated with highest survival rates.94 There is also evidence from one observational study suggesting that a compression depth of more than 6 cm is associated with an increased rate of injury in adults when compared with compression depths of 5–6 cm during manual CPR.96 The ERC endorses the ILCOR recommendation that it is reasonable to aim for a chest compression of approximately 5 cm but not more than 6 cm in the average sized adult. In making this recommendation the ERC recognises that it can be difficult to estimate chest compression depth and that compressions that are too shallow are more harmful than compressions that are too deep. The ERC therefore decided to retain the 2010 guidance that chest compressions should be at least 5 cm but not more than 6 cm. Training should continue to prioritise achieving adequate compression depth. Compression rate Chest compression rate is defined as the actual rate of compressions being given at any one time. It differs from the number of chest compressions in a specific time period, which takes into account any interruptions in chest compressions. G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 89 Two studies, with a total of 13,469 patients, found higher survival among patients who received chest compressions at a rate of 100–120 min−1, compared to >140, 120–139, <80 and 80–99 min−1. Very high chest compression rates were associated with declining chest compression depths.97,98 The ERC recommends, therefore, that chest compressions should be performed at a rate of 100–120 min−1. Minimising pauses in chest compressions Delivery of rescue breaths, shocks, ventilations and rhythm analysis lead to pauses in chest compressions. Pre- and post-shock pauses of less than 10 s, and chest compression fractions >60% are associated with improved outcomes.99–103 Pauses in chest compressions should be minimised, by ensuring CPR providers work effectively together. Firm surface CPR should be performed on a firm surface whenever possible. Air-filled mattresses should be routinely deflated during CPR.104 The evidence for the use of backboards is equivocal.105–109 If a backboard is used, take care to avoid interrupting CPR and dislodging intravenous lines or other tubes during board placement. Chest wall recoil Leaning on the chest preventing full chest wall recoil is common during CPR.110,111 Allowing complete recoil of the chest after each compression results in better venous return to the chest and may improve the effectiveness of CPR.110,112–114 CPR providers should, therefore, take care to avoid leaning after each chest compression. Duty cycle Optimal duty cycle (ratio of the time the chest is compressed to the total time from one compression to the next) has been studied in animal models and simulation studies with inconsistent results.115–123 A recent human observational study has challenged the previously recommended duty cycle of 50:50 by suggesting compression phases >40% might not be feasible, and may be associated with decreased compression depth.124 For CPR providers, the duty cycle is difficult to adjust, and is largely influenced by other chest compression parameters.119,124 In reviewing the evidence, the ERC acknowledges there is very little evidence to recommend any specific duty cycle and, therefore, insufficient new evidence to prompt a change from the currently recommended ratio of 50%. Feedback on compression technique The use of CPR feedback and prompt devices during CPR in clinical practice is intended to improve CPR quality as a means of increasing the chances of ROSC and survival.125,126 The forms of feedback include voice prompts, metronomes, visual dials, numerical displays, waveforms, verbal prompts, and visual alarms. The effect of CPR feedback or prompt devices has been studied in two randomised trials92,127 and 11 observational studies.128–138 None of these studies demonstrated improved survival to discharge with feedback, and only one found a significantly higher ROSC rate in patients where feedback was used. However, in this study feedback was activated at the discretion of the physician and no details of the decision-making process to activate or not activate feedback were provided.136 The use of CPR feedback or prompt devices during CPR should only be considered as part of a broader system of care that should include comprehensive CPR quality improvement initiatives,138,139 rather than as an isolated intervention. Rescue breaths In non-paralysed, gasping pigs with unprotected, unobstructed airways, continuous-chest-compression CPR without artificial ventilation resulted in improved outcome.140 Gasping may be present early after the onset of cardiac arrest in about one third of humans, thus facilitating gas exchange.48 During CPR in intubated humans, however, the median tidal volume per chest compression was only about 40 mL, insufficient for adequate ventilation.141 In witnessed cardiac arrest with ventricular fibrillation, immediate continuous chest compressions tripled survival.142 Accordingly, continuous chest compressions may be most beneficial in the early, ‘electric’ and ‘circulatory’ phases of CPR, while additional ventilation becomes more important in the later, ‘metabolic’ phase.39 During CPR, systemic blood flow, and thus blood flow to the lungs, is substantially reduced, so lower tidal volumes and respiratory rates than normal can maintain effective oxygenation and ventilation.143–146 When the airway is unprotected, a tidal volume of 1 L produces significantly more gastric inflation than a tidal volume of 500 mL.147 Inflation durations of 1 s are feasible without causing excessive gastric insufflation.148 Inadvertent hyperventilation during CPR may occur frequently, especially when using manual bag-valve-mask ventilation in a protected airway. While this increased intrathoracic pressure149 and peak airway pressure,150 a carefully controlled animal experiment revealed no adverse effects.151 From the available evidence we suggest that during adult CPR tidal volumes of approximately 500–600 mL (6–7 mL kg−1) are delivered. Practically, this is the volume required to cause the chest to rise visibly.152 CPR providers should aim for an inflation duration of about 1 s, with enough volume to make the victim’s chest rise, but avoid rapid or forceful breaths. The maximum interruption in chest compression to give two breaths should not exceed 10 s.153 These recommendations apply to all forms of ventilation during CPR when the airway is unprotected, including mouth-tomouth and bag-mask ventilation, with and without supplementary oxygen. Mouth-to-nose ventilation Mouth-to-nose ventilation is an acceptable alternative to mouth-to-mouth ventilation.154 It may be considered if the victim’s mouth is seriously injured or cannot be opened, the CPR provider is assisting a victim in the water, or a mouth-to-mouth seal is difficult to achieve. Mouth-to-tracheostomy ventilation Mouth-to-tracheostomy ventilation may be used for a victim with a tracheostomy tube or tracheal stoma who requires rescue breathing.155 Compression–ventilation ratio Animal data support a ratio of compression to ventilation of greater than 15:2.156–158 A mathematical model suggests that a ratio of 30:2 provides the best compromise between blood flow and oxygen delivery.159,160 A ratio of 30:2 was recommended in Guidelines 2005 and 2010 for the single CPR provider attempting resuscitation of an adult. This decreased the number of interruptions in compression and the no-flow fraction,161,162 and reduced the likelihood of hyperventilation.149,163 Several observational studies have reported slightly improved outcomes after implementation of the guideline changes, which included switching from a compression ventilation ratio of 15:2–30:2.161,162,164,165 The ERC continues, therefore, to recommend a compression to ventilation ratio of 30:2. 90 G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 Compression-only CPR Animal studies have shown that chest-compression-only CPR may be as effective as combined ventilation and compression in the first few minutes after non-asphyxial arrest.140,166 Animal and mathematical model studies of chest-compression-only CPR have also shown that arterial oxygen stores deplete in 2–4 min.158,167 If the airway is open, occasional gasps and passive chest recoil may provide some air exchange.48,141,168–170 Observational studies, classified mostly as very low-quality evidence, have suggested equivalence of chest-compression-only CPR and chest compressions combined with rescue breaths in adults with a suspected cardiac cause for their cardiac arrest.26,171–182 The ERC has carefully considered the balance between potential benefit and harm from compression-only CPR compared to standard CPR that includes ventilation. Our confidence in the equivalence between chest-compression-only and standard CPR is not sufficient to change current practice. The ERC, therefore, endorses the ILCOR recommendations that all CPR providers should perform chest compressions for all patients in cardiac arrest. CPR providers trained and able to perform rescue breaths should perform chest compressions and rescue breaths as this may provide additional benefit for children and those who sustain an asphyxial cardiac arrest175,183,184 or where the EMS response interval is prolonged.179 Use of an automated external defibrillator AEDs are safe and effective when used by laypeople with minimal or no training.185 AEDs make it possible to defibrillate many minutes before professional help arrives. CPR providers should continue CPR with minimal interruption of chest compressions while attaching an AED and during its use. CPR providers should concentrate on following the voice prompts immediately when they are spoken, in particular resuming CPR as soon as instructed, and minimizing interruptions in chest compression. Indeed, pre-shock and post-shock pauses in chest compressions should be as short as possible.99,100,103,186 Standard AEDs are suitable for use in children older than 8 years.187–189 For children between 1 and 8 years paediatric pads should be used, together with an attenuator or a paediatric mode if available; if these are not available, the AED should be used as it is. There are a few case reports of successful use of AEDS in children ages less than 1 year.190,191 The incidence of shockable rhythms in infants is very low except when there is cardiac disease.187–189,192–195 In these rare cases, if an AED is the only defibrillator available, its use should be considered (preferably with a dose attenuator). CPR before defibrillation The importance of immediate defibrillation has always been emphasised in guidelines and during teaching, and is considered to have a major impact on survival from ventricular fibrillation. This concept was challenged in 2005 because evidence suggested that a period of up to 180 s of chest compression before defibrillation might improve survival when the EMS response time exceeded 4–5 min.196,197 Three more recent trials have not confirmed this survival benefit.198–200 An analysis of one randomised trial suggested a decline in survival to hospital discharge by a prolonged period of CPR (180 s) and delayed defibrillation in patients with a shockable initial rhythm.200 Yet, for EMS agencies with higher baseline survival-to-hospital discharge rates (defined as >20% for an initial shockable rhythm), 180 s of CPR prior to defibrillation was more beneficial compared to a shorter period of CPR (30–60 s).201 The ERC recommends that CPR should be continued while a defibrillator or AED is being brought on-site and applied, but defibrillation should not be delayed any longer. Interval between rhythm checks The 2015 ILCOR Consensus on Science reported that there are currently no studies that directly address the question of optimal intervals between rhythm checks, and their effect on survival: ROSC; favourable neurological or functional outcome; survival to discharge; coronary perfusion pressure or cardiac output. In accordance with the ILCOR recommendation, and for consistency with previous guidelines, the ERC recommends that chest compressions should be paused every two minutes to assess the cardiac rhythm. Voice prompts It is critically important that CPR providers pay attention to AED voice prompts and follow them without any delay. Voice prompts are usually programmable, and it is recommended that they be set in accordance with the sequence of shocks and timings for CPR given above. These should include at least: 1. minimise pauses in chest compressions for rhythm analysis and charging; 2. a single shock only, when a shockable rhythm is detected; 3. a voice prompt for immediate resumption of chest compression after the shock delivery; 4. a period of 2 min of CPR before the next voice prompt to reanalyse the rhythm. Devices measuring CPR quality may in addition provide realtime CPR feedback and supplemental voice/visual prompts. The duration of CPR between shocks, as well as the shock sequence and energy levels are discussed further in the Advanced Life Support Chapter.1 In practice, AEDs are used mostly by trained rescuers, where the default setting of AED prompts should be for a compression to ventilation ratio of 30:2. If (in an exception) AEDs are placed in a setting where such trained rescuers are unlikely to be available or present, the owner or distributor may choose to change the settings to compression only. Fully-automatic AEDs Having detected a shockable rhythm, a fully automatic AED will deliver a shock without further action from the CPR provider. One manikin study showed that untrained nursing students committed fewer safety errors using a fully automatic AED compared with a semi-automatic AED.202 A simulated cardiac arrest scenario on a manikin showed that safety was not compromised when untrained lay CPR providers used a fully automatic AED rather than a semiautomatic AED.203 There are no human data to determine whether these findings can be applied to clinical use. Public access defibrillation (PAD) programmes The conditions for successful resuscitation in residential areas are less favourable than in public areas: fewer witnessed arrests, lower bystander CPR rates and, as a consequence, fewer shockable rhythms than in public places. This limits the effectiveness of AED use for victims at home.204 Most studies demonstrating a survival benefit from AED use were conducted with AEDs in G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 91 public places.32,205–208 More recent data from nationwide studies in Japan and the USA confirmed that when an AED was available, victims were defibrillated much sooner and with a better chance of survival.16,209 However, an AED delivered a shock in only 3.7%209 or 1.2%16 of all cardiac arrests. There was a clear inverse relationship in the Japanese study between the number of AEDs available per square km and the interval between collapse and the first shock, leading to a positive relationship with survival. Public access AED programmes should, therefore, be actively implemented in public places with a high density and movement of citizens such as airports, railway stations, bus terminals, sport facilities, shopping malls, offices and casinos where cardiac arrests are usually witnessed and trained CPR providers can quickly be on scene. The density and location of AEDs required for a sufficiently rapid response is not well established, especially when cost-effectiveness is a consideration. Factors such as expected incidence of cardiac arrest, expected number of life-years gained, and reduction in response time of AED-equipped CPR providers compared to that of traditional EMS should inform this decision. Placement of AEDs in areas where one cardiac arrest per 5 years can be expected is considered cost-effective and comparable to other medical interventions.210–212 For residential areas, past experience may help guide AED placement, as may neighbourhood characteristics.213,214 Registration of AEDs for public access, so that dispatchers can direct CPR providers to a nearby AED, may also help to optimise response.215 Cost saving is also possible, as early defibrillation and on-site AED defibrillation may result in lower in-hospital cost.216,217 The full potential of AEDs has not yet been achieved, because they are mostly used in public settings, yet 60–80% of cardiac arrests occur at home. The proportion of patients found in VF is lower at home than in public places, however the absolute number of potentially treatable patients is higher at home.204 Public access defibrillation (PAD) rarely reaches victims at home.208 Different strategies, therefore, are required for early defibrillation in residential areas. Dispatched first responders, such as police and fire fighters will, in general, have longer response times, but they have the potential to reach the whole population.17,36 The logistic problem for first responder programmes is that the CPR provider needs to arrive, not just earlier than the traditional ambulance, but within 5–6 min of the initial call, to enable attempted defibrillation in the electrical or circulatory phase of cardiac arrest.39 With longer delays, the survival benefit decreases: a few minutes gain in time will have less impact when a first responder arrives more than 10 min after the call.34,218 Dispatched lay CPR providers, local to the victim and directed to a nearby AED, may improve bystander CPR rates33 and help reduce the time to defibrillation.40 When implementing an AED programme, community and programme leaders should consider factors such as development of a team with responsibility for monitoring, maintaining the devices, training and retraining individuals who are likely to use the AED, and identification of a group of volunteer individuals who are committed to using the AED for victims of cardiac arrest.219 Funds must be allocated on a permanent basis to maintain the programme. Programmes that make AEDs available in residential areas have only been evaluated for response time, not for survival benefit.40 The acquisition of an AED for individual use at home, even for those considered at high risk of sudden cardiac arrest is not effective.220 The special circumstances chapter provides the evidence underpinning the ERC recommendation that AEDs should be mandatory on board all commercial aircraft in Europe, including regional and low-cost carriers.221 Universal AED signage When a victim collapses an AED must be obtained rapidly: simple and clear signage indicating the location of an AED and the fastest way to it is important. ILCOR has designed such an AED sign that may be recognised worldwide and this is recommended.222 In-hospital use of AEDs There are no published randomised trials comparing in-hospital use of AEDs with manual defibrillators. Two older, observational studies of adults with in-hospital cardiac arrest from shockable rhythms showed higher survival-to-hospital discharge rates when defibrillation was provided through an AED programme than with manual defibrillation alone.223,224 A more recent observational study showed that an AED could be used successfully before the arrival of the hospital resuscitation team.225 Three observational studies showed no improvements in survival to hospital discharge for in-hospital adult cardiac arrest when using an AED compared with manual defibrillation.226–228 In one of these studies,226 patients in the AED group with non-shockable rhythms had a lower survival-to-hospital discharge rate compared with those in the manual defibrillator group (15% vs. 23%; P = 0.04). Another large observational study of 11,695 patients from 204 hospitals also showed that in-hospital AED use was associated with a lower survival-to-discharge rate compared with no AED use (16.3% vs. 19.3%; adjusted rate ratio [RR], 0.85; 95% confidence interval [CI], 0.78–0.92; P < 0.001).229 For non-shockable rhythms, AED use was associated with lower survival (10.4% vs. 15.4%; adjusted RR, 0.74; 95% CI, 0.65–0.83; P < 0.001), and a similar survival rate for shockable rhythms, (38.4% vs. 39.8%; adjusted RR, 1.00; 95% CI, 0.88–1.13; P = 0.99). This suggests that AEDs may cause harmful delays in starting CPR, or interruptions in chest compressions in patients with non-shockable rhythms.230 Only a small proportion (less than 20%) of in-hospital cardiac arrests have an initial shockable rhythm.229,231,232 We recommend the use of AEDs in those areas of the hospital where there is a risk of delayed defibrillation,233 because it will take several minutes for a resuscitation team to arrive, and first responders do not have skills in manual defibrillation. The goal is to attempt defibrillation within 3 min of collapse. In hospital areas where there is rapid access to manual defibrillation, either from trained staff or a resuscitation team, manual defibrillation should be used in preference to an AED. Whichever defibrillation technique is chosen (and some hospitals may choose to have defibrillators that offer both an AED and manual mode) an effective system for training and retraining should be in place.232,234 Sufficient healthcare providers should be trained to enable the goal of providing the first shock within 3 min of collapse anywhere in the hospital. Hospitals should monitor collapse-to-first shock intervals and audit resuscitation outcomes. Risks to the CPR provider and recipients of CPR Risks to the victim who receives CPR who is not in cardiac arrest Many CPR providers do not initiate CPR because they are concerned that delivering chest compressions to a victim who is not in cardiac arrest will cause serious complications. Three studies have investigated the risk of CPR in persons not in cardiac arrest.235–237 Pooled data from these three studies, encompassing 345 patients, found an incidence of bone fracture (ribs and clavicle) of 1.7% (95% CI 0.4–3.1%), pain in the area of chest compression 8.7% (95% CI 5.7–11.7%), and no clinically relevant visceral injury. Bystander CPR extremely rarely leads to serious harm in victims who are eventually found not to be in cardiac arrest. CPR providers should not, 92 G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 therefore, be reluctant to initiate CPR because of concern of causing harm. Risks to the victim who receives CPR who is in cardiac arrest A systematic review of skeletal injuries after manual chest compression reports an incidence of rib fractures ranging from 13% to 97%, and of sternal fractures from 1% to 43%.238 Visceral injuries (lung, heart, abdominal organs) occur less frequently and may or may not be associated with skeletal injury.239 Injuries are more common when the depth of chest compression exceeds 6 cm in the average adult.96 Risks to the CPR provider during training and during real-life CPR Observational studies of training or actual CPR performance and case reports have described rare occurrences of muscle strain, back symptoms, shortness of breath, hyperventilation, pneumothorax, chest pain, myocardial infarction and nerve injury.240,241 The incidence of these events is very low, and CPR training and actual performance is safe in most circumstances.242 Individuals undertaking CPR training should be advised of the nature and extent of the physical activity required during the training programme. Learners and CPR providers who develop significant symptoms (e.g. chest pain or severe shortness of breath) during CPR training should be advised to stop. CPR provider fatigue Several manikin studies have found that chest compression depth can decrease as soon as two minutes after starting chest compressions.243 An in-hospital patient study showed that, even while using real-time feedback, the mean depth of compression deteriorated between 1.5 and 3 min after starting CPR.244 It is therefore recommended that CPR providers change over about every two minutes to prevent a decrease in compression quality due to CPR provider fatigue. Changing CPR providers should not interrupt chest compressions. Risks during defibrillation Many studies of public access defibrillation showed that AEDs can be used safely by laypeople and first responders.185 A systematic review identified eight papers that reported a total of 29 adverse events associated with defibrillation.245 The causes included accidental or intentional defibrillator misuse, device malfunction and accidental discharge during training or maintenance procedures. Four single-case reports described shocks to CPR providers from discharging implantable cardioverter defibrillators (ICDs), in one case resulting in a peripheral nerve injury. No studies were identified which reported harm to CPR providers from attempting defibrillation in wet environments. Although injury to the CPR provider from a defibrillator shock is extremely rare, it has been shown that standard surgical gloves do not provide adequate protection.246–249 CPR providers, therefore, should not continue manual chest compressions during shock delivery, and victims should not be touched during ICD discharge. Direct contact between the CPR provider and the victim should be avoided when defibrillation is performed. Psychological effects One large, prospective trial of public access defibrillation reported few adverse psychological effects associated with CPR or AED use that required intervention.242 Two large, retrospective, questionnaire-based studies found that bystanders who performed CPR regarded their intervention as a positive experience.250,251 Family members witnessing a resuscitation attempt may also derive psychological benefit.252–254 The rare occurrences of adverse psychological effects in CPR providers after performing CPR should be recognised and managed appropriately. Disease transmission The risk of disease transmission during training and actual CPR performance is extremely low.255–257 Wearing gloves during CPR is reasonable, but CPR should not be delayed or withheld if gloves are not available. Barrier devices for use with rescue breaths Three studies showed that barrier devices decrease transmission of bacteria during rescue breathing in controlled laboratory settings.258,259 No studies were identified which examined the safety, effectiveness or feasibility of using barrier devices (such as a face shield or face mask) to prevent victim contact when performing CPR. Nevertheless if the victim is known to have a serious infection (e.g. HIV, tuberculosis, hepatitis B or SARS) a barrier device is recommended. If a barrier device is used, care should be taken to avoid unnecessary interruptions in CPR. Manikin studies indicate that the quality of CPR is superior when a pocket mask is used compared to a bagvalve mask or simple face shield.260–262 Foreign body airway obstruction (choking) Foreign body airway obstruction (FBAO) is an uncommon but potentially treatable cause of accidental death.263 As most choking events are associated with eating, they are commonly witnessed. As victims initially are conscious and responsive, there are often opportunities for early interventions which can be life saving. Recognition Because recognition of airway obstruction is the key to successful outcome, it is important not to confuse this emergency with fainting, myocardial infarction, seizure or other conditions that may cause sudden respiratory distress, cyanosis or loss of consciousness. FBAO usually occurs while the victim is eating or drinking. People at increased risk of FBAO include those with reduced conscious levels, drug and/or alcohol intoxication, neurological impairment with reduced swallowing and cough reflexes (e.g. stroke, Parkinson’s disease), respiratory disease, mental impairment, dementia, poor dentition and older age.264 Fig. 2.5 presents the treatment algorithm for the adult with FBAO. Foreign bodies may cause either mild or severe airway obstruction. It is important to ask the conscious victim “Are you choking?” The victim that is able to speak, cough and breathe has mild obstruction. The victim that is unable to speak, has a weakening cough, is struggling or unable to breathe, has severe airway obstruction. Treatment for mild airway obstruction Coughing generates high and sustained airway pressures and may expel the foreign body. Aggressive treatment with back blows, abdominal thrusts and chest compressions, may cause harm and can worsen the airway obstruction. These treatments should be reserved for victims who have signs of severe airway obstruction. Victims with mild airway obstruction should remain under continuous observation until they improve, as severe airway obstruction may subsequently develop. Treatment for severe airway obstruction The clinical data on choking are largely retrospective and anecdotal. For conscious adults and children over one year of age G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 93 Fig. 2.5. Step by step sequence of actions for the treatment of the adult victim with foreign body airway obstruction. 94 G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 Fig. 2.5. (Continued ). with complete FBAO, case reports have demonstrated the effectiveness of back blows or ‘slaps’, abdominal thrusts and chest thrusts.265 Approximately 50% of episodes of airway obstruction are not relieved by a single technique.266 The likelihood of success is increased when combinations of back blows or slaps, and abdominal and chest thrusts are used.265 Treatment of foreign body airway obstruction in an unresponsive victim A randomised trial in cadavers267 and two prospective studies in anaesthetised volunteers268,269 showed that higher airway pressures can be generated using chest thrusts compared with abdominal thrusts. Bystander initiation of chest compression for unresponsive or unconscious victims of FBAO was independently associated with good neurological outcome (odds ratio, 10.57; 95% CI, 2.472–65.059, P < 0.0001).270 Chest compressions should, therefore, be started promptly if the victim becomes unresponsive or unconscious. After 30 compressions attempt 2 rescue breaths, and continue CPR until the victim recovers and starts to breathe nor- mally. Aftercare and referral for medical review Following successful treatment of FBAO, foreign material may nevertheless remain in the upper or lower airways and cause complications later. Victims with a persistent cough, difficulty swallowing or the sensation of an object being still stuck in the throat should, therefore, be referred for a medical opinion. Abdominal thrusts and chest compressions can potentially cause serious internal injuries and all victims successfully treated with these measures should be examined afterwards for injury. Resuscitation of children (see also Recognition of Cardiac Arrest section) and victims of drowning (see also The Chain of Survival section) Many children do not receive resuscitation because potential CPR providers fear causing harm if they are not specifically trained in resuscitation for children. This fear is unfounded: it is far better to use the adult BLS sequence for resuscitation of a child than to do nothing. For ease of teaching and retention, laypeople should be taught that the adult sequence may also be used for children who are not responsive and not breathing normally. The following minor modifications to the adult sequence will make it even more suitable for use in children: • Give 5 initial rescue breaths before starting chest compressions. • Give CPR for 1 min before going for help in the unlikely event the CPR provider is alone. • Compress the chest by at least one third of its depth; use 2 fingers for an infant under one year; use 1 or 2 hands for a child over 1 year as needed to achieve an adequate depth of compression. The same modifications of 5 initial breaths and 1 min of CPR by the lone CPR provider before getting help, may improve outcome for victims of drowning. This modification should be taught only to those who have a specific duty of care to potential drowning victims (e.g. lifeguards). Collaborators Leo L. Bossaert, University of Antwerp, Antwerp, Belgium, Antonio Caballero, Emergency Department, Hospital Universitario Virgen del Rocío, Sevilla, Spain, Pascal Cassan, Global First Aid Reference Centre, International Federation of Red Cross and Red Crescent, Paris, France, Cristina Granja, Emergency and Intensive Care Department, Hospital de Faro, Centro Hospitalar do Algarve, Porto, Portugal, Claudio Sandroni, Department of Anaesthesiology and Intensive Care, Catholic University School of Medicine, Rome, Italy, David A. Zideman, Imperial College Healthcare NHS Trust, London, UK, Jerry P. Nolan, Department of Anaesthesia and Intensive Care Medicine, Royal United Hospital, Bath, UK, Ian Maconochie, Paediatric Emergency Medicine and NIHR BRC, Imperial College, London, UK, Robert Greif, Department of Anaesthesiology and Pain Medicine, University Hospital Bern and University Bern, Bern, Switzerland. Conflicts of interest Gavin D. Perkins Editor Resuscitation Jasmeet Soar Editor Resuscitation Anthony J. Handley Medical advisor BA, Virgin, Places for people, Life saving Societies, Trading Company Secretary RCUK Giuseppe Ristagno Expert advice ZOLL: ECG interpretation Maaret Castren Medical advisory Board Falck Foundation Rudolph W. Koster Medical advisor Physio Control and HeartSine, Research grants PhysioControl, Philips, Zoll, Cardiac Science, Defibtech, Jolife Volker Wenzel Research grants, Medical advisor, Speakers honorarium “AOP Orphan” Pharma Jan-Thorsten Gräsner No conflict of interest reported Koenraad G. Monsieurs No conflict of interest reported Michael A. Smyth No conflict of interest reported Theresa Mariero Olasveengen No conflict of interest reported Violetta Raffay No conflict of interest reported G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 95 References 1. Soar J, Nolan JP, Bottiger BW, et al. European Resuscitation Council guidelines for resuscitation 2015 section 3 adult advanced life support. Resuscitation 2015;95:99–146. 2. Zideman DA, De Buck EDJ, Singletary EM, et al. European Resuscitation Council guidelines for resuscitation 2015 section 9 first aid. Resuscitation 2015;95:277–86. 3. Perkins GD, Travers AH, Considine J, et al. Part 3: Adult basic life support and automated external defibrillation: 2015 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations. Resuscitation 2015;95:e43–70. 4. Berdowski J, Berg RA, Tijssen JG, Koster RW. Global incidences of out-ofhospital cardiac arrest and survival rates: systematic review of 67 prospective studies. Resuscitation 2010;81:1479–87. 5. Grasner JT, Herlitz J, Koster RW, Rosell-Ortiz F, Stamatakis L, Bossaert L. Quality management in resuscitation – towards a European cardiac arrest registry (EuReCa). Resuscitation 2011;82:989–94. 6. Grasner JT, Bossaert L. Epidemiology and management of cardiac arrest: what registries are revealing. Best Pract Res Clin Anaesthesiol 2013;27:293–306. 7. Cobb LA, Fahrenbruch CE, Olsufka M, Copass MK. Changing incidence of outof-hospital ventricular fibrillation, 1980–2000. JAMA 2002;288:3008–13. 8. Rea TD, Pearce RM, Raghunathan TE, et al. Incidence of out-of-hospital cardiac arrest. Am J Cardiol 2004;93:1455–60. 9. Vaillancourt C, Verma A, Trickett J, et al. Evaluating the effectiveness of dispatch-assisted cardiopulmonary resuscitation instructions. Acad Emerg Med 2007;14:877–83. 10. Agarwal DA, Hess EP, Atkinson EJ, White RD. Ventricular fibrillation in Rochester, Minnesota: experience over 18 years. Resuscitation 2009;80:1253–8. 11. Ringh M, Herlitz J, Hollenberg J, Rosenqvist M, Svensson L. Out of hospital cardiac arrest outside home in Sweden, change in characteristics, outcome and availability for public access defibrillation. Scand J Trauma Resusc Emerg Med 2009;17:18. 12. Hulleman M, Berdowski J, de Groot JR, et al. Implantable cardioverterdefibrillators have reduced the incidence of resuscitation for out-of-hospital cardiac arrest caused by lethal arrhythmias. Circulation 2012;126:815–21. 13. Blom MT, Beesems SG, Homma PC, et al. Improved survival after out-ofhospital cardiac arrest and use of automated external defibrillators. Circulation 2014;130:1868–75. 14. Cummins R, Thies W. Automated external defibrillators and the Advanced Cardiac Life Support Program: a new initiative from the American Heart Association. Am J Emerg Med 1991;9:91–3. 15. Waalewijn RA, Nijpels MA, Tijssen JG, Koster RW. Prevention of deterioration of ventricular fibrillation by basic life support during out-of-hospital cardiac arrest. Resuscitation 2002;54:31–6. 16. Weisfeldt ML, Sitlani CM, Ornato JP, et al. Survival after application of automatic external defibrillators before arrival of the emergency medical system: evaluation in the resuscitation outcomes consortium population of 21 million. J Am Coll Cardiol 2010;55:1713–20. 17. Berdowski J, Blom MT, Bardai A, Tan HL, Tijssen JG, Koster RW. Impact of onsite or dispatched automated external defibrillator use on survival after out-ofhospital cardiac arrest. Circulation 2011;124:2225–32. 18. Nolan J, Soar J, Eikeland H. The chain of survival. Resuscitation 2006;71:270–1. 19. Muller D, Agrawal R, Arntz HR. How sudden is sudden cardiac death? Circulation 2006;114:1146–50. 20. Waalewijn RA, Tijssen JG, Koster RW. Bystander initiated actions in outof-hospital cardiopulmonary resuscitation: results from the Amsterdam Resuscitation Study (ARRESUST). Resuscitation 2001;50:273–9. 21. Sasson C, Rogers MA, Dahl J, Kellermann AL. Predictors of survival from out-ofhospital cardiac arrest: a systematic review and meta-analysis. Circ Cardiovasc Qual Outcomes 2010;3:63–81. 22. Nehme Z, Andrew E, Bernard S, Smith K. Comparison of out-of-hospital cardiac arrest occurring before and after paramedic arrival: epidemiology, survival to hospital discharge and 12-month functional recovery. Resuscitation 2015;89:50–7. 23. Takei Y, Nishi T, Kamikura T, et al. Do early emergency calls before patient collapse improve survival after out-of-hospital cardiac arrests? Resuscitation 2015;88:20–7. 24. Valenzuela TD, Roe DJ, Cretin S, Spaite DW, Larsen MP. Estimating effectiveness of cardiac arrest interventions: a logistic regression survival model. Circulation 1997;96:3308–13. 25. Holmberg M, Holmberg S, Herlitz J, Gardelov B. Survival after cardiac arrest outside hospital in Sweden. Swedish Cardiac Arrest Registry. Resuscitation 1998;36:29–36. 26. Holmberg M, Holmberg S, Herlitz J. Factors modifying the effect of bystander cardiopulmonary resuscitation on survival in out-of-hospital cardiac arrest patients in Sweden. Eur Heart J 2001;22:511–9. 27. Wissenberg M, Lippert FK, Folke F, et al. Association of national initiatives to improve cardiac arrest management with rates of bystander intervention and patient survival after out-of-hospital cardiac arrest. JAMA 2013;310:1377–84. 28. Hasselqvist-Ax I, Riva G, Herlitz J, et al. Early cardiopulmonary resuscitation in out-of-hospital cardiac arrest. N Engl J Med 2015;372:2307–15. 29. Rea TD, Fahrenbruch C, Culley L, et al. CPR with chest compresssions alone or with rescue breathing. N Engl J Med 2010;363:423–33. 30. Svensson L, Bohm K, Castren M, et al. Compression-only CPR or standard CPR in out-of-hospital cardiac arrest. N Engl J Med 2010;363:434–42. 31. Hupfl M, Selig HF, Nagele P. Chest-compression-only versus standard cardiopulmonary resuscitation: a meta-analysis. Lancet 2010;376:1552–7. 32. Valenzuela TD, Roe DJ, Nichol G, Clark LL, Spaite DW, Hardman RG. Outcomes of rapid defibrillation by security officers after cardiac arrest in casinos. N Engl J Med 2000;343:1206–9. 33. Ringh M, Rosenqvist M, Hollenberg J, et al. Mobile-phone dispatch of laypersons for CPR in out-of-hospital cardiac arrest. N Engl J Med 2015;372:2316–25. 34. Larsen MP, Eisenberg MS, Cummins RO, Hallstrom AP. Predicting survival from out-of-hospital cardiac arrest: a graphic model. Ann Emerg Med 1993;22:1652–8. 35. Nolan JP, Soar J, Cariou A, et al. European Resuscitation Council and European Society of Intensive Care Medicine Guidelines for Post-resuscitation Care 2015. Section 5 Post-resuscitation care. Resuscitation 2015;95:201–21. 36. van Alem AP, Vrenken RH, de Vos R, Tijssen JG, Koster RW. Use of automated external defibrillator by first responders in out of hospital cardiac arrest: prospective controlled trial. Br Med J 2003;327:1312. 37. Fothergill RT, Watson LR, Chamberlain D, Virdi GK, Moore FP, Whitbread M. Increases in survival from out-of-hospital cardiac arrest: a five year study. Resuscitation 2013;84:1089–92. 38. Perkins GD, Lall R, Quinn T, et al. Mechanical versus manual chest compression for out-of-hospital cardiac arrest (PARAMEDIC): a pragmatic, cluster randomised controlled trial. Lancet 2015;385:947–55. 39. Weisfeldt ML, Becker LB. Resuscitation after cardiac arrest: a 3-phase timesensitive model. JAMA 2002;288:3035–8. 40. Zijlstra JA, Stieglis R, Riedijk F, Smeekes M, van der Worp WE, Koster RW. Local lay rescuers with AEDs, alerted by text messages, contribute to early defibrillation in a Dutch out-of-hospital cardiac arrest dispatch system. Resuscitation 2014;85:1444–9. 41. Kerber RE, Becker LB, Bourland JD, et al. Automatic external defibrillators for public access defibrillation: recommendations for specifying and reporting arrhythmia analysis algorithm performance, incorporating new waveforms, and enhancing safety. A statement for health professionals from the American Heart Association Task Force on Automatic External Defibrillation, Subcommittee on AED Safety and Efficacy. Circulation 1997;95:1677–82. 42. Calle PA, Mpotos N, Calle SP, Monsieurs KG. Inaccurate treatment decisions of automated external defibrillators used by emergency medical services personnel: incidence, cause and impact on outcome. Resuscitation 2015;88:68–74. 43. Bahr J, Klingler H, Panzer W, Rode H, Kettler D. Skills of lay people in checking the carotid pulse. Resuscitation 1997;35:23–6. 44. Nyman J, Sihvonen M. Cardiopulmonary resuscitation skills in nurses and nursing students. Resuscitation 2000;47:179–84. 45. Tibballs J, Russell P. Reliability of pulse palpation by healthcare personnel to diagnose paediatric cardiac arrest. Resuscitation 2009;80:61–4. 46. Tibballs J, Weeranatna C. The influence of time on the accuracy of healthcare personnel to diagnose paediatric cardiac arrest by pulse palpation. Resuscitation 2010;81:671–5. 47. Moule P. Checking the carotid pulse: diagnostic accuracy in students of the healthcare professions. Resuscitation 2000;44:195–201. 48. Bobrow BJ, Zuercher M, Ewy GA, et al. Gasping during cardiac arrest in humans is frequent and associated with improved survival. Circulation 2008;118:2550–4. 49. Perkins GD, Stephenson B, Hulme J, Monsieurs KG. Birmingham assessment of breathing study (BABS). Resuscitation 2005;64:109–13. 50. Perkins GD, Walker G, Christensen K, Hulme J, Monsieurs KG. Teaching recognition of agonal breathing improves accuracy of diagnosing cardiac arrest. Resuscitation 2006;70:432–7. 51. Breckwoldt J, Schloesser S, Arntz HR. Perceptions of collapse and assessment of cardiac arrest by bystanders of out-of-hospital cardiac arrest (OOHCA). Resuscitation 2009;80:1108–13. 52. Stecker EC, Reinier K, Uy-Evanado A, et al. Relationship between seizure episode and sudden cardiac arrest in patients with epilepsy: a communitybased study. Circ Arrhythm Electrophysiol 2013;6:912–6. 53. Kuisma M, Boyd J, Vayrynen T, Repo J, Nousila-Wiik M, Holmstrom P. Emergency call processing and survival from out-of-hospital ventricular fibrillation. Resuscitation 2005;67:89–93. 54. Berdowski J, Beekhuis F, Zwinderman AH, Tijssen JG, Koster RW. Importance of the first link: description and recognition of an out-of-hospital cardiac arrest in an emergency call. Circulation 2009;119:2096–102. 55. Heward A, Damiani M, Hartley-Sharpe C. Does the use of the Advanced Medical Priority Dispatch System affect cardiac arrest detection? Emerg Med J 2004;21:115–8. 56. Eisenberg MS, Hallstrom AP, Carter WB, Cummins RO, Bergner L, Pierce J. Emergency CPR instruction via telephone. Am J Public Health 1985;75:47–50. 57. Stipulante S, Tubes R, El Fassi M, et al. Implementation of the ALERT algorithm, a new dispatcher-assisted telephone cardiopulmonary resuscitation protocol, in non-Advanced Medical Priority Dispatch System (AMPDS) Emergency Medical Services centres. Resuscitation 2014;85:177–81. 58. Castren M, Kuisma M, Serlachius J, Skrifvars M. Do health care professionals report sudden cardiac arrest better than laymen? Resuscitation 2001;51:265–8. 59. Hallstrom AP, Cobb LA, Johnson E, Copass MK. Dispatcher assisted CPR: implementation and potential benefit. A 12-year study. Resuscitation 2003;57:123–9. 96 G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 60. Dami F, Fuchs V, Praz L, Vader JP. Introducing systematic dispatcher-assisted cardiopulmonary resuscitation (telephone-CPR) in a non-Advanced Medical Priority Dispatch System (AMPDS): implementation process and costs. Resuscitation 2010;81:848–52. 61. Nurmi J, Pettila V, Biber B, Kuisma M, Komulainen R, Castren M. Effect of protocol compliance to cardiac arrest identification by emergency medical dispatchers. Resuscitation 2006;70:463–9. 62. Lewis M, Stubbs BA, Eisenberg MS. Dispatcher-assisted cardiopulmonary resuscitation: time to identify cardiac arrest and deliver chest compression instructions. Circulation 2013;128:1522–30. 63. Hauff SR, Rea TD, Culley LL, Kerry F, Becker L, Eisenberg MS. Factors impeding dispatcher-assisted telephone cardiopulmonary resuscitation. Ann Emerg Med 2003;42:731–7. 64. Bohm K, Stalhandske B, Rosenqvist M, Ulfvarson J, Hollenberg J, Svensson L. Tuition of emergency medical dispatchers in the recognition of agonal respiration increases the use of telephone assisted CPR. Resuscitation 2009;80:1025–8. 65. Bohm K, Rosenqvist M, Hollenberg J, Biber B, Engerstrom L, Svensson L. Dispatcher-assisted telephone-guided cardiopulmonary resuscitation: an underused lifesaving system. Eur J Emerg Med 2007;14:256–9. 66. Bång A, Herlitz J, Martinell S. Interaction between emergency medical dispatcher and caller in suspected out-of-hospital cardiac arrest calls with focus on agonal breathing. A review of 100 tape recordings of true cardiac arrest cases. Resuscitation 2003;56:25–34. 67. Roppolo LP, Westfall A, Pepe PE, et al. Dispatcher assessments for agonal breathing improve detection of cardiac arrest. Resuscitation 2009;80: 769–72. 68. Tanaka Y, Taniguchi J, Wato Y, Yoshida Y, Inaba H. The continuous quality improvement project for telephone-assisted instruction of cardiopulmonary resuscitation increased the incidence of bystander CPR and improved the outcomes of out-of-hospital cardiac arrests. Resuscitation 2012;83: 1235–41. 69. Clawson J, Olola C, Heward A, Patterson B. Cardiac arrest predictability in seizure patients based on emergency medical dispatcher identification of previous seizure or epilepsy history. Resuscitation 2007;75: 298–304. 70. Akahane M, Ogawa T, Tanabe S, et al. Impact of telephone dispatcher assistance on the outcomes of pediatric out-of-hospital cardiac arrest. Crit Care Med 2012;40:1410–6. 71. Bray JE, Deasy C, Walsh J, Bacon A, Currell A, Smith K. Changing EMS dispatcher CPR instructions to 400 compressions before mouth-to-mouth improved bystander CPR rates. Resuscitation 2011;82:1393–8. 72. Culley LL, Clark JJ, Eisenberg MS, Larsen MP. Dispatcher-assisted telephone CPR: common delays and time standards for delivery. Ann Emerg Med 1991;20:362–6. 73. Rea TD, Eisenberg MS, Culley LL, Becker L. Dispatcher-assisted cardiopulmonary resuscitation and survival in cardiac arrest. Circulation 2001;104:2513–6. 74. Hallstrom AP. Dispatcher-assisted “phone” cardiopulmonary resuscitation by chest compression alone or with mouth-to-mouth ventilation. Crit Care Med 2000;28:N190–2. 75. Stromsoe A, Svensson L, Axelsson AB, et al. Improved outcome in Sweden after out-of-hospital cardiac arrest and possible association with improvements in every link in the chain of survival. Eur Heart J 2015;36:863–71. 76. Takei Y, Inaba H, Yachida T, Enami M, Goto Y, Ohta K. Analysis of reasons for emergency call delays in Japan in relation to location: high incidence of correctable causes and the impact of delays on patient outcomes. Resuscitation 2010;81:1492–8. 77. Herlitz J, Engdahl J, Svensson L, Young M, Angquist KA, Holmberg S. A short delay from out of hospital cardiac arrest to call for ambulance increases survival. Eur Heart J 2003;24:1750–5. 78. Nehme Z, Andrew E, Cameron P, et al. Direction of first bystander call for help is associated with outcome from out-of-hospital cardiac arrest. Resuscitation 2014;85:42–8. 79. Birkenes TS, Myklebust H, Neset A, Olasveengen TM, Kramer-Johansen J. Video analysis of dispatcher-rescuer teamwork-Effects on CPR technique and performance. Resuscitation 2012;83:494–9. 80. Birkenes TS, Myklebust H, Kramer-Johansen J. Time delays and capability of elderly to activate speaker function for continuous telephone CPR. Scand J Trauma Resusc Emerg Med 2013;21:40. 81. Marsch S, Tschan F, Semmer NK, Zobrist R, Hunziker PR, Hunziker S. ABC versus CAB for cardiopulmonary resuscitation: a prospective, randomized simulatorbased trial. Swiss Med Wkly 2013;143:w13856. 82. Lubrano R, Cecchetti C, Bellelli E, et al. Comparison of times of intervention during pediatric CPR maneuvers using ABC and CAB sequences: a randomized trial. Resuscitation 2012;83:1473–7. 83. Sekiguchi H, Kondo Y, Kukita I. Verification of changes in the time taken to initiate chest compressions according to modified basic life support guidelines. Am J Emerg Med 2013;31:1248–50. 84. Kobayashi M, Fujiwara A, Morita H, et al. A manikin-based observational study on cardiopulmonary resuscitation skills at the Osaka Senri medical rally. Resuscitation 2008;78:333–9. 85. Cha KC, Kim HJ, Shin HJ, Kim H, Lee KH, Hwang SO. Hemodynamic effect of external chest compressions at the lower end of the sternum in cardiac arrest patients. J Emerg Med 2013;44:691–7. 86. Qvigstad E, Kramer-Johansen J, Tomte O, et al. Clinical pilot study of different hand positions during manual chest compressions monitored with capnography. Resuscitation 2013;84:1203–7. 87. Orlowski JP. Optimum position for external cardiac compression in infants and young children. Ann Emerg Med 1986;15:667–73. 88. Chamberlain D, Smith A, Colquhoun M, Handley AJ, Kern KB, Woollard M. Randomised controlled trials of staged teaching for basic life support: 2. Comparison of CPR performance and skill retention using either staged instruction or conventional training. Resuscitation 2001;50:27–37. 89. Handley AJ. Teaching hand placement for chest compression – a simpler technique. Resuscitation 2002;53:29–36. 90. Handley AJ, Handley JA. Performing chest compressions in a confined space. Resuscitation 2004;61:55–61. 91. Perkins GD, Stephenson BT, Smith CM, Gao F. A comparison between over-the-head and standard cardiopulmonary resuscitation. Resuscitation 2004;61:155–61. 92. Hostler D, Everson-Stewart S, Rea TD, et al. Effect of real-time feedback during cardiopulmonary resuscitation outside hospital: prospective, clusterrandomised trial. Br Med J 2011;342:d512. 93. Stiell IG, Brown SP, Christenson J, et al. What is the role of chest compression depth during out-of-hospital cardiac arrest resuscitation?*. Crit Care Med 2012;40:1192–8. 94. Stiell IG, Brown SP, Nichol G, et al. What is the optimal chest compression depth during out-of-hospital cardiac arrest resuscitation of adult patients? Circulation 2014;130:1962–70. 95. Vadeboncoeur T, Stolz U, Panchal A, et al. Chest compression depth and survival in out-of-hospital cardiac arrest. Resuscitation 2014;85:182–8. 96. Hellevuo H, Sainio M, Nevalainen R, et al. Deeper chest compression – more complications for cardiac arrest patients? Resuscitation 2013;84:760–5. 97. Idris AH, Guffey D, Pepe PE, et al. Chest compressionrates and survival following out-of-hospital cardiac arrest. Crit Care Med 2015;43:840–8. 98. Idris AH, Guffey D, Aufderheide TP, et al. Relationship between chest compression rates and outcomes from cardiac arrest. Circulation 2012;125: 3004–12. 99. Cheskes S, Schmicker RH, Verbeek PR, et al. The impact of peri-shock pause on survival from out-of-hospital shockable cardiac arrest during the Resuscitation Outcomes Consortium PRIMED trial. Resuscitation 2014;85:336–42. 100. Cheskes S, Schmicker RH, Christenson J, et al. Perishock pause: an independent predictor of survival from out-of-hospital shockable cardiac arrest. Circulation 2011;124:58–66. 101. Vaillancourt C, Everson-Stewart S, Christenson J, et al. The impact of increased chest compression fraction on return of spontaneous circulation for out-ofhospital cardiac arrest patients not in ventricular fibrillation. Resuscitation 2011;82:1501–7. 102. Sell RE, Sarno R, Lawrence B, et al. Minimizing pre- and post-defibrillation pauses increases the likelihood of return of spontaneous circulation (ROSC). Resuscitation 2010;81:822–5. 103. Christenson J, Andrusiek D, Everson-Stewart S, et al. Chest compression fraction determines survival in patients with out-of-hospital ventricular fibrillation. Circulation 2009;120:1241–7. 104. Delvaux AB, Trombley MT, Rivet CJ, et al. Design and development of a cardiopulmonary resuscitation mattress. J Intensive Care Med 2009;24:195–9. 105. Nishisaki A, Maltese MR, Niles DE, et al. Backboards are important when chest compressions are provided on a soft mattress. Resuscitation 2012;83:1013–20. 106. Sato H, Komasawa N, Ueki R, et al. Backboard insertion in the operating table increases chest compression depth: a manikin study. J Anesth 2011;25:770–2. 107. Perkins GD, Smith CM, Augre C, et al. Effects of a backboard, bed height, and operator position on compression depth during simulated resuscitation. Intensive Care Med 2006;32:1632–5. 108. Perkins GD, Kocierz L, Smith SC, McCulloch RA, Davies RP. Compression feedback devices over estimate chest compression depth when performed on a bed. Resuscitation 2009;80:79–82. 109. Cloete G, Dellimore KH, Scheffer C, Smuts MS, Wallis LA. The impact of backboard size and orientation on sternum-to-spine compression depth and compression stiffness in a manikin study of CPR using two mattress types. Resuscitation 2011;82:1064–70. 110. Niles DE, Sutton RM, Nadkarni VM, et al. Prevalence and hemodynamic effects of leaning during CPR. Resuscitation 2011;82:S23–6. 111. Fried DA, Leary M, Smith DA, et al. The prevalence of chest compression leaning during in-hospital cardiopulmonary resuscitation. Resuscitation 2011;82:1019–24. 112. Zuercher M, Hilwig RW, Ranger-Moore J, et al. Leaning during chest compressions impairs cardiac output and left ventricular myocardial blood flow in piglet cardiac arrest. Crit Care Med 2010;38:1141–6. 113. Aufderheide TP, Pirrallo RG, Yannopoulos D, et al. Incomplete chest wall decompression: a clinical evaluation of CPR performance by EMS personnel and assessment of alternative manual chest compression–decompression techniques. Resuscitation 2005;64:353–62. 114. Yannopoulos D, McKnite S, Aufderheide TP, et al. Effects of incomplete chest wall decompression during cardiopulmonary resuscitation on coronary and cerebral perfusion pressures in a porcine model of cardiac arrest. Resuscitation 2005;64:363–72. 115. Jung E, Babbs CF, Lenhart S, Protopopescu VA. Optimal strategy for cardiopulmonary resuscitation with continuous chest compression. Acad Emerg Med 2006;13:715–21. G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 97 116. Betz AE, Menegazzi JJ, Logue ES, Callaway CW, Wang HE. A randomized comparison of manual, mechanical and high-impulse chest compression in a porcine model of prolonged ventricular fibrillation. Resuscitation 2006;69: 495–501. 117. Koeken Y, Aelen P, Noordergraaf GJ, Paulussen I, Woerlee P, Noordergraaf A. The influence of nonlinear intra-thoracic vascular behaviour and compression characteristics on cardiac output during CPR. Resuscitation 2011;82:538–44. 118. Sunde K, Wik L, Naess PA, Ilebekk A, Nicolaysen G, Steen PA. Effect of different compression–decompression cycles on haemodynamics during ACD-CPR in pigs. Resuscitation 1998;36:123–31. 119. Handley AJ, Handley JA. The relationship between rate of chest compression and compression:relaxation ratio. Resuscitation 1995;30:237–41. 120. Swart GL, Mateer JR, DeBehnke DJ, Jameson SJ, Osborn JL. The effect of compression duration on hemodynamics during mechanical high-impulse CPR. Acad Emerg Med 1994;1:430–7. 121. Dean JM, Koehler RC, Schleien CL, et al. Improved blood flow during prolonged cardiopulmonary resuscitation with 30% duty cycle in infant pigs. Circulation 1991;84:896–904. 122. Halperin HR, Tsitlik JE, Guerci AD, et al. Determinants of blood flow to vital organs during cardiopulmonary resuscitation in dogs. Circulation 1986;73:539–50. 123. Fitzgerald KR, Babbs CF, Frissora HA, Davis RW, Silver DI. Cardiac output during cardiopulmonary resuscitation at various compression rates and durations. Am J Physiol 1981;241. H442-H8. 124. Johnson B, Coult J, Fahrenbruch C, et al. Cardiopulmonary resuscitation duty cycle in out-of-hospital cardiac arrest. Resuscitation 2015;87:86–90. 125. Yeung J, Meeks R, Edelson D, Gao F, Soar J, Perkins GD. The use of CPR feedback/prompt devices during training and CPR performance: a systematic review. Resuscitation 2009;80:743–51. 126. Kirkbright S, Finn J, Tohira H, Bremner A, Jacobs I, Celenza A. Audiovisual feedback device use by health care professionals during CPR: a systematic review and meta-analysis of randomised and non-randomised trials. Resuscitation 2014;85:460–71. 127. Bohn A, Weber TP, Wecker S, et al. The addition of voice prompts to audiovisual feedback and debriefing does not modify CPR quality or outcomes in out of hospital cardiac arrest – a prospective, randomized trial. Resuscitation 2011;82:257–62. 128. Abella BS, Edelson DP, Kim S, et al. CPR quality improvement during in-hospital cardiac arrest using a real-time audiovisual feedback system. Resuscitation 2007;73:54–61. 129. Berg RA, Sanders AB, Milander M, Tellez D, Liu P, Beyda D. Efficacy of audio-prompted rate guidance in improving resuscitator performance of cardiopulmonary resuscitation on children. Acad Emerg Med 1994;1:35–40. 130. Bobrow BJ, Vadeboncoeur TF, Stolz U, et al. The influence of scenario-based training and real-time audiovisual feedback on out-of-hospital cardiopulmonary resuscitation quality and survival from out-of-hospital cardiac arrest. Ann Emerg Med 2013;62, 47-56 e1. 131. Chiang WC, Chen WJ, Chen SY, et al. Better adherence to the guidelines during cardiopulmonary resuscitation through the provision of audio-prompts. Resuscitation 2005;64:297–301. 132. Kern KB, Sanders AB, Raife J, Milander MM, Otto CW, Ewy GA. A study of chest compression rates during cardiopulmonary resuscitation in humans: the importance of rate-directed chest compressions. Arch Intern Med 1992;152:145–9. 133. Kramer-Johansen J, Myklebust H, Wik L, et al. Quality of out-of-hospital cardiopulmonary resuscitation with real time automated feedback: a prospective interventional study. Resuscitation 2006;71:283–92. 134. Lukas RP, Grasner JT, Seewald S, et al. Chest compression quality management and return of spontaneous circulation: a matched-pair registry study. Resuscitation 2012;83:1212–8. 135. Niles D, Nysaether J, Sutton R, et al. Leaning is common during in-hospital pediatric CPR, and decreased with automated corrective feedback. Resuscitation 2009;80:553–7. 136. Sainio M, Kamarainen A, Huhtala H, et al. Real-time audiovisual feedback system in a physician-staffed helicopter emergency medical service in Finland: the quality results and barriers to implementation. Scand J Trauma Resusc Emerg Med 2013;21:50. 137. Sutton RM, Niles D, French B, et al. First quantitative analysis of cardiopulmonary resuscitation quality during in-hospital cardiac arrests of young children. Resuscitation 2014;85:70–4. 138. Couper K, Kimani P, Abella BS, Chilwan M, Cooke MW, Davies RP. The system-wide effect of real-time audiovisual feedback and postevent debriefing for in-hospital cardiac arrest: the cardiopulmonary resuscitation quality improvement initiative. Crit Care Med 2015, http://dx.doi.org/10.1097/ CCM.0000000000001202 (in press). 139. Couper K, Salman B, Soar J, Finn J, Perkins GD. Debriefing to improve outcomes from critical illness: a systematic review and meta-analysis. Intensive Care Med 2013;39:1513–23. 140. Kern KB, Hilwig RW, Berg RA, Sanders AB, Ewy GA. Importance of continuous chest compressions during cardiopulmonary resuscitation: improved outcome during a simulated single lay-rescuer scenario. Circulation 2002;105: 645–9. 141. Deakin CD, O’Neill JF, Tabor T. Does compression-only cardiopulmonary resuscitation generate adequate passive ventilation during cardiac arrest? Resuscitation 2007;75:53–9. 142. Bobrow BJ, Clark LL, Ewy GA, et al. Minimally interrupted cardiac resuscitation by emergency medical services for out-of-hospital cardiac arrest. JAMA 2008;299:1158–65. 143. Idris A, Wenzel V, Banner MJ, Melker RJ. Smaller tidal volumes minimize gastric inflation during CPR with an unprotected airway. Circulation 1995;92. I-I759. 144. Winkler M, Mauritz W, Hackl W, et al. Effects of half the tidal volume during cardiopulmonary resuscitation on acid-base balance and haemodynamics in pigs. Eur J Emerg Med 1998;5:201–6. 145. Idris A, Gabrielli A, Caruso L. Smaller tidal volume is safe and effective for bagvalve-ventilation, but not for mouth-to-mouth ventilation: an animal model for basic life support. Circulation 1999;100:I–I644. 146. Dorph E, Wik L, Steen PA. Arterial blood gases with 700 ml tidal volumes during out-of-hospital CPR. Resuscitation 2004;61:23–7. 147. Wenzel V, Idris AH, Banner MJ, Kubilis PS, Williams JLJ. Influence of tidal volume on the distribution of gas between the lungs and stomach in the nonintubated patient receiving positive-pressure ventilation. Crit Care Med 1998;26: 364–8. 148. von Goedecke A, Wagner-Berger HG, Stadlbauer KH, et al. Effects of decreasing peak flow rate on stomach inflation during bag-valve-mask ventilation. Resuscitation 2004;63:131–6. 149. Aufderheide TP, Sigurdsson G, Pirrallo RG, et al. Hyperventilationinduced hypotension during cardiopulmonary resuscitation. Circulation 2004;109:1960–5. 150. O’Neill JF, Deakin CD. Do we hyperventilate cardiac arrest patients? Resuscitation 2007;73:82–5. 151. Gazmuri RJ, Ayoub IM, Radhakrishnan J, Motl J, Upadhyaya MP. Clinically plausible hyperventilation does not exert adverse hemodynamic effects during CPR but markedly reduces end-tidal PCO(2). Resuscitation 2012;83:259–64. 152. Baskett P, Nolan J, Parr M. Tidal volumes which are perceived to be adequate for resuscitation. Resuscitation 1996;31:231–4. 153. Beesems SG, Wijmans L, Tijssen JG, Koster RW. Duration of ventilations during cardiopulmonary resuscitation by lay rescuers and first responders: relationship between delivering chest compressions and outcomes. Circulation 2013;127:1585–90. 154. Ruben H. The immediate treatment of respiratory failure. Br J Anaesth 1964;36:542–9. 155. Kowalik MM. Mouth-to-tracheostomy tube ventilation in an emergency situation. Resuscitation 2007;73:322–3. 156. Sanders AB, Kern KB, Berg RA, Hilwig RW, Heidenrich J, Ewy GA. Survival and neurologic outcome after cardiopulmonary resuscitation with four different chest compression-ventilation ratios. Ann Emerg Med 2002;40: 553–62. 157. Dorph E, Wik L, Stromme TA, Eriksen M, Steen PA. Quality of CPR with three different ventilation:compression ratios. Resuscitation 2003;58:193–201. 158. Dorph E, Wik L, Stromme TA, Eriksen M, Steen PA. Oxygen delivery and return of spontaneous circulation with ventilation:compression ratio 2:30 versus chest compressions only CPR in pigs. Resuscitation 2004;60:309–18. 159. Babbs CF, Kern KB. Optimum compression to ventilation ratios in CPR under realistic, practical conditions: a physiological and mathematical analysis. Resuscitation 2002;54:147–57. 160. Fenici P, Idris AH, Lurie KG, Ursella S, Gabrielli A. What is the optimal chest compression–ventilation ratio? Curr Opin Crit Care 2005;11:204–11. 161. Sayre MR, Cantrell SA, White LJ, Hiestand BC, Keseg DP, Koser S. Impact of the 2005 American Heart Association cardiopulmonary resuscitation and emergency cardiovascular care guidelines on out-of-hospital cardiac arrest survival. Prehosp Emerg Care 2009;13:469–77. 162. Olasveengen TM, Vik E, Kuzovlev A, Sunde K. Effect of implementation of new resuscitation guidelines on quality of cardiopulmonary resuscitation and survival. Resuscitation 2009;80:407–11. 163. Aufderheide TP, Lurie KG. Death by hyperventilation: a common and lifethreatening problem during cardiopulmonary resuscitation. Crit Care Med 2004;32. S345–51. 164. Steinmetz J, Barnung S, Nielsen SL, Risom M, Rasmussen LS. Improved survival after an out-of-hospital cardiac arrest using new guidelines. Acta Anaesthesiol Scand 2008;52:908–13. 165. Hinchey PR, Myers JB, Lewis R, et al. Improved out-of-hospital cardiac arrest survival after the sequential implementation of 2005 AHA guidelines for compressions, ventilations, and induced hypothermia: the Wake County experience. Ann Emerg Med 2010;56:348–57. 166. Chandra NC, Gruben KG, Tsitlik JE, et al. Observations of ventilation during resuscitation in a canine model. Circulation 1994;90:3070–5. 167. Turner I, Turner S, Armstrong V. Does the compression to ventilation ratio affect the quality of CPR: a simulation study. Resuscitation 2002;52:55–62. 168. Geddes LA, Rundell A, Otlewski M, Pargett M. How much lung ventilation is obtained with only chest-compression CPR? Cardiovasc Eng 2008;8:145–8. 169. Berg RA, Kern KB, Hilwig RW, et al. Assisted ventilation does not improve outcome in a porcine model of single-rescuer bystander cardiopulmonary resuscitation. Circulation 1997;95:1635–41. 170. Berg RA, Kern KB, Hilwig RW, Ewy GA. Assisted ventilation during ‘bystander’ CPR in a swine acute myocardial infarction model does not improve outcome. Circulation 1997;96:4364–71. 171. Panchal AR, Bobrow BJ, Spaite DW, et al. Chest compression-only cardiopulmonary resuscitation performed by lay rescuers for adult out-of-hospital cardiac arrest due to non-cardiac aetiologies. Resuscitation 2013;84: 435–9. 98 G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 172. Kitamura T, Iwami T, Kawamura T, et al. Time-dependent effectiveness of chest compression-only and conventional cardiopulmonary resuscitation for out-ofhospital cardiac arrest of cardiac origin. Resuscitation 2011;82:3–9. 173. Mohler MJ, Wendel CS, Mosier J, et al. Cardiocerebral resuscitation improves out-of-hospital survival in older adults. J Am Geriatr Soc 2011;59: 822–6. 174. Bobrow BJ, Spaite DW, Berg RA, et al. Chest compression-only CPR by lay rescuers and survival from out-of-hospital cardiac arrest. JAMA 2010;304:1447–54. 175. Kitamura T, Iwami T, Kawamura T, Nagao K, Tanaka H, Hiraide A. BystanderInitiated Rescue Breathing for Out-of-Hospital Cardiac Arrests of Noncardiac Origin. Circulation 2010;122:293–9. 176. Ong ME, Ng FS, Anushia P, et al. Comparison of chest compression only and standard cardiopulmonary resuscitation for out-of-hospital cardiac arrest in Singapore. Resuscitation 2008;78:119–26. 177. Bohm K, Rosenqvist M, Herlitz J, Hollenberg J, Svensson L. Survival is similar after standard treatment and chest compression only in out-of-hospital bystander cardiopulmonary resuscitation. Circulation 2007;116:2908–12. 178. SOS-KANTO Study Group. Cardiopulmonary resuscitation by bystanders with chest compression only (SOS-KANTO): an observational study. Lancet 2007;369:920–6. 179. Iwami T, Kawamura T, Hiraide A, et al. Effectiveness of bystander-initiated cardiac-only resuscitation for patients with out-of-hospital cardiac arrest. Circulation 2007;116:2900–7. 180. Bossaert L, Van Hoeyweghen R. Evaluation of cardiopulmonary resuscitation (CPR) techniques. The Cerebral Resuscitation Study Group. Resuscitation 1989;17:S99–109, discussion S99–206. 181. Gallagher EJ, Lombardi G, Gennis P. Effectiveness of bystander cardiopulmonary resuscitation and survival following out-of-hospital cardiac arrest. JAMA 1995;274:1922–5. 182. Olasveengen TM, Wik L, Steen PA. Standard basic life support vs. continuous chest compressions only in out-of-hospital cardiac arrest. Acta Anaesthesiol Scand 2008;52:914–9. 183. Kitamura T, Iwami T, Kawamura T, et al. Conventional and chest-compressiononly cardiopulmonary resuscitation by bystanders for children who have out-of-hospital cardiac arrests: a prospective, nationwide, population-based cohort study. Lancet 2010;375:1347–54. 184. Goto Y, Maeda T, Goto Y. Impact of dispatcher-assisted bystander cardiopulmonary resuscitation on neurological outcomes in children with out-of-hospital cardiac arrests: a prospective, nationwide, population-based cohort study. J Am Heart Assoc 2014;3:e000499. 185. Yeung J, Okamoto D, Soar J, Perkins GD. AED training and its impact on skill acquisition, retention and performance – a systematic review of alternative training methods. Resuscitation 2011;82:657–64. 186. Edelson DP, Abella BS, Kramer-Johansen J, et al. Effects of compression depth and pre-shock pauses predict defibrillation failure during cardiac arrest. Resuscitation 2006;71:137–45. 187. Mitani Y, Ohta K, Yodoya N, et al. Public access defibrillation improved the outcome after out-of-hospital cardiac arrest in school-age children: a nationwide, population-based, Utstein registry study in Japan. Europace 2013;15:1259–66. 188. Johnson MA, Grahan BJ, Haukoos JS, et al. Demographics, bystander CPR, and AED use in out-of-hospital pediatric arrests. Resuscitation 2014;85:920–6. 189. Akahane M, Tanabe S, Ogawa T, et al. Characteristics and outcomes of pediatric out-of-hospital cardiac arrest by scholastic age category. Pediatr Crit Care Med 2013;14:130–6. 190. Bar-Cohen Y, Walsh EP, Love BA, Cecchin F. First appropriate use of automated external defibrillator in an infant. Resuscitation 2005;67:135–7. 191. Divekar A, Soni R. Successful parental use of an automated external defibrillator for an infant with long-QT syndrome. Pediatrics 2006;118:e526–9. 192. Rodriguez-Nunez A, Lopez-Herce J, Garcia C, Dominguez P, Carrillo A, Bellon JM. Pediatric defibrillation after cardiac arrest: initial response and outcome. Crit Care 2006;10:R113. 193. Samson RA, Nadkarni VM, Meaney PA, Carey SM, Berg MD, Berg RA. Outcomes of in-hospital ventricular fibrillation in children. N Engl J Med 2006;354:2328–39. 194. Atkins DL, Everson-Stewart S, Sears GK, et al. Epidemiology and outcomes from out-of-hospital cardiac arrest in children: the Resuscitation Outcomes Consortium Epistry-Cardiac Arrest. Circulation 2009;119:1484–91. 195. Bardai A, Berdowski J, van der Werf C, et al. Incidence, causes, and outcomes of out-of-hospital cardiac arrest in children. A comprehensive, prospective, population-based study in the Netherlands. J Am Coll Cardiol 2011;57: 1822–8. 196. Cobb LA, Fahrenbruch CE, Walsh TR, et al. Influence of cardiopulmonary resuscitation prior to defibrillation in patients with out-of-hospital ventricular fibrillation. JAMA 1999;281:1182–8. 197. Wik L, Hansen TB, Fylling F, et al. Delaying defibrillation to give basic cardiopulmonary resuscitation to patients with out-of-hospital ventricular fibrillation: a randomized trial. JAMA 2003;289:1389–95. 198. Jacobs IG, Finn JC, Oxer HF, Jelinek GA. CPR before defibrillation in out-ofhospital cardiac arrest: a randomized trial. Emerg Med Aust 2005;17:39–45. 199. Baker PW, Conway J, Cotton C, et al. Defibrillation or cardiopulmonary resuscitation first for patients with out-of-hospital cardiac arrests found by paramedics to be in ventricular fibrillation? A randomised control trial. Resuscitation 2008;79:424–31. 200. Stiell IG, Nichol G, Leroux BG, et al. Early versus later rhythm analysis in patients with out-of-hospital cardiac arrest. N Engl J Med 2011;365:787–97. 201. Rea T, Prince D, Morrison L, et al. Association between survival and early versus later rhythm analysis in out-of-hospital cardiac arrest: do agency-level factors influence outcomes? Ann Emerg Med 2014;64:1–8. 202. Monsieurs KG, Vogels C, Bossaert LL, Meert P, Calle PA. A study comparing the usability of fully automatic versus semi-automatic defibrillation by untrained nursing students. Resuscitation 2005;64:41–7. 203. Hosmans TP, Maquoi I, Vogels C, et al. Safety of fully automatic external defibrillation by untrained lay rescuers in the presence of a bystander. Resuscitation 2008;77:216–9. 204. Weisfeldt ML, Everson-Stewart S, Sitlani C, et al. Ventricular tachyarrhythmias after cardiac arrest in public versus at home. N Engl J Med 2011;364:313–21. 205. Caffrey SL, Willoughby PJ, Pepe PE, Becker LB. Public use of automated external defibrillators. N Engl J Med 2002;347:1242–7. 206. Page RL, Hamdan MH, McKenas DK. Defibrillation aboard a commercial aircraft. Circulation 1998;97:1429–30. 207. O’Rourke MF, Donaldson E, Geddes JS. An airline cardiac arrest program. Circulation 1997;96:2849–53. 208. The Public Access Defibrillation Trial Investigators. Public-access defibrillation and survival after out-of-hospital cardiac arrest. N Engl J Med 2004;351:637–46. 209. Kitamura T, Iwami T, Kawamura T, Nagao K, Tanaka H, Hiraide A. Nationwide public-access defibrillation in Japan. N Engl J Med 2010;362:994–1004. 210. Nichol G, Valenzuela T, Roe D, Clark L, Huszti E, Wells GA. Cost effectiveness of defibrillation by targeted responders in public settings. Circulation 2003;108:697–703. 211. Nichol G, Huszti E, Birnbaum A, et al. Cost-effectiveness of lay responder defibrillation for out-of-hospital cardiac arrest. Ann Emerg Med 2009;54, 226-35 e1-2. 212. Folke F, Lippert FK, Nielsen SL, et al. Location of cardiac arrest in a city center: strategic placement of automated external defibrillators in public locations. Circulation 2009;120:510–7. 213. Chan TC, Li H, Lebovic G, et al. Identifying locations for public access defibrillators using mathematical optimization. Circulation 2013;127:1801–9. 214. Folke F, Gislason GH, Lippert FK, et al. Differences between out-of-hospital cardiac arrest in residential and public locations and implications for publicaccess defibrillation. Circulation 2010;122:623–30. 215. Hansen CM, Lippert FK, Wissenberg M, et al. Temporal trends in coverage of historical cardiac arrests using a volunteer-based network of automated external defibrillators accessible to laypersons and emergency dispatch centers. Circulation 2014;130:1859–67. 216. van Alem AP, Dijkgraaf MG, Tijssen JG, Koster RW. Health system costs of out-of-hospital cardiac arrest in relation to time to shock. Circulation 2004;110:1967–73. 217. Berdowski J, Kuiper MJ, Dijkgraaf MG, Tijssen JG, Koster RW. Survival and health care costs until hospital discharge of patients treated with onsite, dispatched or without automated external defibrillator. Resuscitation 2010;81:962–7. 218. Waalewijn RA, de Vos R, Tijssen JG, Koster RW. Survival models for out-ofhospital cardiopulmonary resuscitation from the perspectives of the bystander, the first responder, and the paramedic. Resuscitation 2001;51:113–22. 219. Priori SG, Bossaert LL, Chamberlain DA, et al. Policy statement: ESC-ERC recommendations for the use of automated external defibrillators (AEDs) in Europe. Resuscitation 2004;60:245–52. 220. Bardy GH, Lee KL, Mark DB, et al. Home use of automated external defibrillators for sudden cardiac arrest. N Engl J Med 2008;358:1793–804. 221. Truhlar A, Deakin CD, Soar J, et al. European Resuscitation Council guidelines for resuscitation 2015 section 4 cardiac arrest in special circumstances. Resuscitation 2015;95:147–200. 222. ILCOR presents a universal AED sign. European Resuscitation Council, 2008.; 2015, available from https://www.erc.edu/index.php/newsItem/en/nid=204/ (accessed 28.06.15). 223. Zafari AM, Zarter SK, Heggen V, et al. A program encouraging early defibrillation results in improved in-hospital resuscitation efficacy. J Am Coll Cardiol 2004;44:846–52. 224. Destro A, Marzaloni M, Sermasi S, Rossi F. Automatic external defibrillators in the hospital as well? Resuscitation 1996;31:39–43. 225. Kloppe C, Jeromin A, Kloppe A, Ernst M, Mugge A, Hanefeld C. First responder for in-hospital resuscitation: 5-year experience with an automated external defibrillator-based program. J Emerg Med 2013;44:1077–82. 226. Forcina MS, Farhat AY, O’Neil WW, Haines DE. Cardiac arrest survival after implementation of automated external defibrillator technology in the inhospital setting. Crit Care Med 2009;37:1229–36. 227. Smith RJ, Hickey BB, Santamaria JD. Automated external defibrillators and survival after in-hospital cardiac arrest: early experience at an Australian teaching hospital. Crit Care Resusc 2009;11:261–5. 228. Smith RJ, Hickey BB, Santamaria JD. Automated external defibrillators and in-hospital cardiac arrest: patient survival and device performance at an Australian teaching hospital. Resuscitation 2011;82:1537–42. 229. Chan PS, Krumholz HM, Spertus JA, et al. Automated external defibrillators and survival after in-hospital cardiac arrest. JAMA 2010;304:2129–36. 230. Gibbison B, Soar J. Automated external defibrillator use for in-hospital cardiac arrest is not associated with improved survival. Evid Based Med 2011;16:95–6. 231. Nolan JP, Soar J, Smith GB, et al. Incidence and outcome of in-hospital cardiac arrest in the United Kingdom National Cardiac Arrest Audit. Resuscitation 2014;85:987–92. 232. De Regge M, Monsieurs KG, Vandewoude K, Calle PA. Should we use automated external defibrillators in hospital wards? Acta Clin Belg 2012;67:241–5. G.D. Perkins et al. / Resuscitation 95 (2015) 81–99 99 233. Chan PS, Krumholz HM, Nichol G, Nallamothu BK. Delayed time to defibrillation after in-hospital cardiac arrest. N Engl J Med 2008;358:9–17. 234. Spearpoint KG, Gruber PC, Brett SJ. Impact of the Immediate Life Support course on the incidence and outcome of in-hospital cardiac arrest calls: an observational study over 6 years. Resuscitation 2009;80:638–43. 235. White L, Rogers J, Bloomingdale M, et al. Dispatcher-assisted cardiopulmonary resuscitation: risks for patients not in cardiac arrest. Circulation 2010;121:91–7. 236. Haley KB, Lerner EB, Pirrallo RG, Croft H, Johnson A, Uihlein M. The frequency and consequences of cardiopulmonary resuscitation performed by bystanders on patients who are not in cardiac arrest. Prehosp Emerg Care 2011;15:282–7. 237. Moriwaki Y, Sugiyama M, Tahara Y, et al. Complications of bystander cardiopulmonary resuscitation for unconscious patients without cardiopulmonary arrest. J Emerg Trauma Shock 2012;5:3–6. 238. Hoke RS, Chamberlain D. Skeletal chest injuries secondary to cardiopulmonary resuscitation. Resuscitation 2004;63:327–38. 239. Miller AC, Rosati SF, Suffredini AF, Schrump DS. A systematic review and pooled analysis of CPR-associated cardiovascular and thoracic injuries. Resuscitation 2014;85:724–31. 240. Sullivan F, Avstreih D. Pneumothorax during CPR training: case report and review of the CPR literature. Prehosp Disaster Med 2000;15:64–9. 241. Cheung W, Gullick J, Thanakrishnan G, et al. Injuries occurring in hospital staff attending medical emergency team (MET) calls – a prospective, observational study. Resuscitation 2009;80:1351–6. 242. Peberdy MA, Ottingham LV, Groh WJ, et al. Adverse events associated with lay emergency response programs: the public access defibrillation trial experience. Resuscitation 2006;70:59–65. 243. McDonald CH, Heggie J, Jones CM, Thorne CJ, Hulme J. Rescuer fatigue under the 2010 ERC guidelines, and its effect on cardiopulmonary resuscitation (CPR) performance. Emerg Med J 2013;30:623–7. 244. Sugerman NT, Edelson DP, Leary M, et al. Rescuer fatigue during actual in-hospital cardiopulmonary resuscitation with audiovisual feedback: a prospective multicenter study. Resuscitation 2009;80:981–4. 245. Hoke RS, Heinroth K, Trappe HJ, Werdan K. Is external defibrillation an electric threat for bystanders? Resuscitation 2009;80:395–401. 246. Sullivan JL, Chapman FW. Will medical examination gloves protect rescuers from defibrillation voltages during hands-on defibrillation? Resuscitation 2012;83:1467–72. 247. Petley GW, Cotton AM, Deakin CD. Hands-on defibrillation: theoretical and practical aspects of patient and rescuer safety. Resuscitation 2012;83:551–6. 248. Deakin CD, Lee-Shrewsbury V, Hogg K, Petley GW. Do clinical examination gloves provide adequate electrical insulation for safe hands-on defibrillation? I: Resistive properties of nitrile gloves. Resuscitation 2013;84:895–9. 249. Petley GW, Deakin CD. Do clinical examination gloves provide adequate electrical insulation for safe hands-on defibrillation? II: Material integrity following exposure to defibrillation waveforms. Resuscitation 2013;84:900–3. 250. Axelsson A, Herlitz J, Ekstrom L, Holmberg S. Bystander-initiated cardiopulmonary resuscitation out-of-hospital. A first description of the bystanders and their experiences. Resuscitation 1996;33:3–11. 251. Axelsson A, Herlitz J, Karlsson T, et al. Factors surrounding cardiopulmonary resuscitation influencing bystanders’ psychological reactions. Resuscitation 1998;37:13–20. 252. Jabre P, Belpomme V, Azoulay E, et al. Family presence during cardiopulmonary resuscitation. N Engl J Med 2013;368:1008–18. 253. Jabre P, Tazarourte K, Azoulay E, et al. Offering the opportunity for family to be present during cardiopulmonary resuscitation: 1-year assessment. Intensive Care Med 2014;40:981–7. 254. Compton S, Fernandez R. Presence during cardiopulmonary resuscitation is beneficial to family members in the out-of-hospital setting. Evid Based Med 2014;19:13. 255. Bierens JJ, Berden HJ. Basic-CPR and AIDS: are volunteer life-savers prepared for a storm? Resuscitation 1996;32:185–91. 256. Mejicano GC, Maki DG. Infections acquired during cardiopulmonary resuscitation: estimating the risk and defining strategies for prevention. Ann Intern Med 1998;129:813–28. 257. Torabi-Parizi P, Davey Jr RT, Suffredini AF, Chertow DS. Ethical and practical considerations in providing critical care to patients with ebola virus disease. Chest 2015;147:1460–6. 258. Blenkharn JI, Buckingham SE, Zideman DA. Prevention of transmission of infection during mouth-to-mouth resuscitation. Resuscitation 1990;19:151–7. 259. Cydulka RK, Connor PJ, Myers TF, Pavza G, Parker M. Prevention of oral bacterial flora transmission by using mouth-to-mask ventilation during CPR. J Emerg Med 1991;9:317–21. 260. Adelborg K, Bjornshave K, Mortensen MB, Espeseth E, Wolff A, Lofgren B. A randomised crossover comparison of mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation by surf lifeguards in a manikin. Anaesthesia 2014;69:712–6. 261. Adelborg K, Dalgas C, Grove EL, Jorgensen C, Al-Mashhadi RH, Lofgren B. Mouth-to-mouth ventilation is superior to mouth-to-pocket mask and bag-valve-mask ventilation during lifeguard CPR: a randomized study. Resuscitation 2011;82:618–22. 262. Paal P, Falk M, Sumann G, et al. Comparison of mouth-to-mouth, mouthto-mask and mouth-to-face-shield ventilation by lay persons. Resuscitation 2006;70:117–23. 263. Fingerhut LA, Cox CS, Warner M. International comparative analysis of injury mortality. Findings from the ICE on injury statistics. International Collaborative Effort on Injury Statistics. Adv Data 1998:1–20. 264. Wong SC, Tariq SM. Cardiac arrest following foreign-body aspiration. Respir Care 2011;56:527–9. 265. Proceedings of the 2005 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science with treatment recommendations. Resuscitation 2005;67:157–341. 266. Redding JS. The choking controversy: critique of evidence on the Heimlich maneuver. Crit Care Med 1979;7:475–9. 267. Langhelle A, Sunde K, Wik L, Steen PA. Airway pressure with chest compressions versus Heimlich manoeuvre in recently dead adults with complete airway obstruction. Resuscitation 2000;44:105–8. 268. Guildner CW, Williams D, Subitch T. Airway obstructed by foreign material: the Heimlich maneuver. JACEP 1976;5:675–7. 269. Ruben H, Macnaughton FI. The treatment of food-choking. Practitioner 1978;221:725–9. 270. Kinoshita K, Azuhata T, Kawano D, Kawahara Y. Relationships between pre-hospital characteristics and outcome in victims of foreign body airway obstruction during meals. Resuscitation 2015;88:63–7.