Edited by Conor Deasy SECTION 1

1.1 Basic 1 1.2 5

1.1 Sameer A. Pathan

compressions and rapid , which ESSENTIALS significantly improves the chances of survival from ventricular fibrillation (VF) in OHCA.1–3 CPR 1 A patient with sudden out-of-hospital (OHCA) requires activation of plus defibrillation within 3 to 5 minutes of collapse the Chain of Survival, which includes early high-quality cardiopulmonary resuscitation following VF in OHCA can produce survival rates (CPR) and early defibrillation. The medical dispatcher plays a crucial and as high as 49% to 75%.5–7 Each minute of delay central role in this process. before defibrillation reduces the probability of survival to hospital discharge by 10% to 12%.2,3 2 Over telephone, the dispatcher should provide instructions for external chest The final links in the Chain of Survival are effec- compressions only CPR to any adult caller wishing to aid a victim of OHCA. This approach tive ALS and integrated post-resuscitation care has shown absolute survival benefit and improved rates of bystander CPR. targeted at optimizing and preserving cardiac 8 3 In the out-of-hospital setting, bystanders should deliver chest compressions to any and cerebral function. unresponsive patient with abnormal or absent breathing. Bystanders who are trained, able, and willing to give rescue breaths should do so without compromising the main focus on high quality of chest compressions. Development of protocols Any guidelines for BLS must be evidence based 4 Early defibrillation should be regarded as part of Basic Life Support (BLS) training, as and consistent across a wide range of providers. it is essential to terminate ventricular fibrillation. Many countries have established national com- mittees to advise community groups, 5 There is strong emphasis on the implementation of public-access defibrillation services and the medical profession of appropri- programs, which include the use of automated external defibrillators by untrained or ate BLS guidelines. Box 1.1.1 lists the national asso- minimally trained lay rescuers in public areas. ciations that make up the International Liaison Committee on Resuscitation (ILCOR). The ILCOR group meets every 5 years to review the BLS This chapter outlines an approach to BLS that and ALS guidelines and to evaluate the scientific Introduction can be delivered by any rescuer while awaiting evidence that may lead to changes. Basic Life Support (BLS) aims to maintain respira- the arrival of emergency medical services (EMS) tions and circulation in the cardiac arrest victim. or medical expertise able to provide Advanced BLS’s major focus is on CPR with minimal use Life Support (ALS) (see Chapter 1.2). of ancillary equipment. It includes chest com- Box 1.1.1 Membership of the International pressions with or without rescue breathing Chain of Survival Liaison Committee on Resuscitation 2015 and defibrillation with a manual or automated The Chain of Survival is the series of linked American Association (AHA) external defibrillator (AED). BLS can be success- actions taken in treating a victim of sudden European Resuscitation Council (ERC) fully performed immediately by any rescuer with cardiac arrest.4 The first steps are early recogni- Heart and Foundation of Canada (HSFC) Resuscitation Council of Southern Africa (RCSA) little or no prior training or experience using tion of an individual at risk of or in active cardiac Australian and New Zealand Committee on dispatcher-assisted telephone instructions in the arrest and an immediate call to activate help from Resuscitation (ANZCOR) OHCA. BLS has proven value in aiding the survival EMS. This is followed by early commencement InterAmerican Heart Foundation (IAHF) Resuscitation Council of Asia (RCA) of neurologically intact victims.1–3 of CPR with an emphasis on high-quality chest

1 1.1 BASIC LIFE SUPPORT

as it is available, and prompts are followed if it is Basic Life Support automatic or semiautomatic. Change to the adult Basic Life Support in 2015 D Dangers? A significant change to the adult BLS in the ILCOR 2010 resuscitation guidelines was the recommen- dation for a Compressions, Airway, Breathing Responsive? (CAB) sequence instead of an Airway, Breathing, R Compressions (ABC) sequence. This was aimed at minimizing any delay in initiating chest compres- sions, particularly when the sudden collapse is S Send for help witnessed and likely of cardiac origin. In the 2015 guidelines, the ILCOR task force differed from regional resuscitation councils in deciding to use A Open airway the CAB or ABC sequence, as limited literature exists to make any single recommendation. Regional variations B Normal breathing? There are regional variations in the interpretation and incorporation of opening the airway within the BLS algorithm. In the European Resuscita- Start CPR tion Council (ERC) and the ARC with the NZRC C 30 compressions : 2 breaths algorithm, opening the airway comes before assessment of breathing followed by compres- sion if required. This effectively preserves the ABC sequence to avoid confusion, whereas the Attach Defibrillator (AED) American Heart Association (AHA) Resuscita- as soon as available and follow its prompts D tion Guidelines 2015 continue to advise a CAB sequence for CPR. The ILCOR 2015 universal BLS algorithm with Continue CPR until responsiveness or ARC and NZRC considerations is discussed in the normal breathing return remainder of this chapter. Check for response and send for help The patient who has collapsed is rapidly assessed FIG. 1.1.1 Australian Resuscitation Council and New Zealand Resuscitation Council Basic Life Support flowchart. AED, Automated external defibrillator; CPR, cardiopulmonary resuscitation. (Reproduced from to determine whether he or she is unresponsive https://resus.org.au/guidelines/flowcharts-3/) and not breathing normally, indicating pos- sible cardiorespiratory arrest. For an untrained rescuer, this can be sequentially assessed by Revision of the Basic Life Support http://www.resus.org.au/policy/guidelines/ and a gentle ‘shake and shout’ and observation of guidelines, 2015 http://www.nzrc.org.nz/guidelines/ respectively. the patient’s response rather than by looking The most recent revision of the BLS guidelines specifically for signs of life (which was deemed occurred in 2015 and followed a comprehensive potentially confusing). The rescuer can then evaluation of the scientific literature for each DRSABCD approach to Basic Life assess the unresponsive patient for absent or aspect of BLS. Evidence evaluation worksheets Support inadequate breathing. were developed and were then considered by A flowchart for the initial evaluation and provi- If cardiac arrest is assumed, the rescuer ILCOR (available at http://circ.ahajournals.org/ sion of BLS for the collapsed patient is shown in should immediately telephone the EMS (call content/132/16_suppl_1/S40). The final recom- Fig. 1.1.1. This is based on a DRSABCD approach, first) and initiate chest compressions as advised 8 mendations were published in late 2015. the letters of which stand for Dangers? Respon- by the dispatcher to initiate BLS care. A trained sive? Send for help; open Airway; normal rescuer or health care provider may check for Australian Resuscitation Council and Breathing? start CPR; and attach Defibrillator. This ­unresponsiveness and abnormal breathing at the New Zealand Resuscitation Council process therefore includes the recognition that a same time and then activate the EMS or cardiac Basic Life Support guidelines patient has collapsed and is unresponsive, a safe arrest team. Each national committee endorsed the guide- approach to checking for danger and immedi- The health care rescuers may commence lines with minor regional variations to take into ately sending for help to activate the emergency CPR with ventilation for approximately 2 min- account local practices. The recommendations medical response team. This is followed by open- utes before calling the EMS (CPR first) when the of the Australian Resuscitation Council (ARC) ing the airway and briefly checking for abnormal collapse is due to suspected airway obstruction combined with those of the New Zealand or absent breathing, with rapid commencement () or inadequate ventilation (, ­Resuscitation Council (NZRC) on BLS were of chest compressions and rescue breaths if the hanging, etc.) or for infants and children up to published jointly in 2016 and are available at pulse is absent. A defibrillator is attached as soon 18 years of age.

2 1.1 BASIC LIFE SUPPORT 1 RESUSCITATION Assessment of airway and breathing effectiveness of the chest compressions. There Passive ventilation with chest recoil Make an assessment of the airway if a patient has is strong emphasis on delivering high-quality The rationale for hands-only or chest compres- collapsed and is apparently unconscious. Place chest compressions: rescuers should push hard sion–only CPR is that if the airway is open, the patient supine if face down and look for any to a depth of at least 5 cm (or 2 inches) at a rate passive ventilation may provide some gas signs of obvious airway obstruction. A trained of approximately 100 to 120 compressions per exchange during the recoil phase of the chest lay rescuer or health care rescuer may open the minute, allowing full chest recoil by avoiding compressions. However, the passive ventilation airway using the head tilt–chin lift manoeuvre leaning on the chest between the compres- technique should not be considered an alterna- when assessing breathing or giving ventilations. sions and minimizing interruptions in the chest tive to conventional CPR. The EMS responders Care should be taken not to move the patient’s compressions.8 Hence the maxim, ‘Push hard, may adopt the passive ventilation technique neck in the case of suspected trauma; however, push fast, allow complete recoil and minimize as part of a bundled intervention of care with the airway takes precedence over any . interruptions’. During BLS in the OHCA setting, free-flowing oxygen supply during a continuous Adequate is assessed by visually there is insufficient evidence to support a pulse high-quality chest compression phase. inspecting the movement of the chest wall, check while performing CPR. Therefore all atten- whether it rises and falls, and listening for tion should be paid to delivering high-quality CPR Emergency medical services bundled upper airway sounds. In cases of cardiac arrest, and noting any obvious change in the patient’s intervention cardiopulmonary occasional deep respirations (agonal gasps) response until the EMS arrives. resuscitation care may continue for a few minutes after the initial In a broad definition, most EMS bundled interven- collapse; these are not considered to represent Cardiac or thoracic pump mechanism tions include 200 initial chest compressions fol- normal breathing. In suspected foreign body There is ongoing debate as to whether external lowed by single and immediate resumption obstruction, one can assess the severity of chest compressions generate blood flow via of next 200 chest compressions before a rhythm obstruction by effective cough in a conscious a ‘cardiac’ or a ‘thoracic pump’ mechanism. or pulse check. The rate of compressions remains patient. If the initial assessment of an uncon- Whatever the predominant mechanism of blood 100 to 120 per minute and ventilation is achieved scious patient reveals adequate respiration the flow, owing to the relative rigidity of the chest with bag-mask device at the rate of 8 per minute so victim should be turned to the semi-prone or wall, chest compressions result in around 20% as to minimize interruptions during compressions. lateral , followed by constant of normal cardiac output in the adult. Few EMS systems also use passive oxygen insuf- checks to ensure continued respiration and the flation with basic airway adjunct and rely solely maintenance of breathing while awaiting the Chest compressions with ventilation on passive ventilations during chest recoil. There arrival of the EMS. Rescuers willing, trained, and able to provide is a growing literature in support of EMS bundled The current recommendation for an untrained ventilation should give two rescue breaths after intervention as an alternative to conventional CPR lay rescuer is that he or she should not attempt to each 30 compressions, for a compression/venti- for witnessed shockable OHCA. palpate for a pulse, as a pulse check is inaccurate lation ratio of 30/2. However, time to deliver two in this setting.8 A health care provider should take rescue breaths should be kept to 10 seconds or Airway and breathing no more than 10 seconds to check for a pulse. less, followed by immediate resumption of the The airway is opened using the head tilt–chin If the rescuer does not definitely feel a pulse chest compressions. lift manoeuvre when assessing breathing or within 10 seconds, chest compressions should giving ventilations in an unresponsive adult or be started immediately. ‘Chest compression only’ child. Solid material in the oropharynx should cardiopulmonary resuscitation be removed with a careful sweep of a finger if Cardiopulmonary resuscitation In the case of untrained rescuers, where rescuers inspection of the airway reveals visible foreign In the past, the BLS sequence of rescuer opening are unable or unwilling to perform mouth-to- material or vomitus in the upper airway. the airway, positioning the patient, retrieving a mouth breaths (‘standard’ CPR), ‘compression barrier or giving mouth-to-mouth expired air only’ CPR is recommended. This technique is also Foreign body airway obstruction resuscitation (EAR) breaths as two initial ‘rescue recommended for EMS dispatchers providing If a victim suspected of a foreign body airway breaths’ often delayed the chest compressions. telephone advice to callers seeking to aid adults obstruction (FBAO) can cough, he or she should These are also difficult and challenging for an with suspected OHCA. be encouraged to cough and expel it out. If the untrained lay rescuer to implement and have Health care professionals as well as lay cough is ineffective and the patient is conscious, resulted in significant delays or, worse still, no rescuers are often uncomfortable giving he or she may be given up to five back blows attempt at CPR at all. Therefore the current rec- mouth-to-mouth ventilation to an unknown with the heel of a hand and then up to five chest ommendation is to initiate CPR with immediate victim of cardiac arrest. This should not, how- thrusts at the same compression point as in CPR, chest compressions if the patient is assumed to ever, prevent them from carrying out at least but sharper and slower. These techniques may be in cardiac arrest. ‘hands-only’ or ‘chest compression–only’ CPR, be alternated, but it is also important to call for as bystander CPR has been shown to improve the EMS. If the victim becomes unresponsive, survival over no CPR at all.9 The consensus on CPR may be started as described in Fig. 1.1.1. Management compression-only CPR compared with con- Chest compressions ventional CPR suggests no difference between Airway obstruction manoeuvres A number of All lay rescuers (trained or untrained) and health the two methods in survival and favourable manoeuvres have been proposed to clear the care rescuers should begin CPR by perform- neurological or functional outcome in the short airway if it is completely obstructed by a foreign ing chest compressions on the lower half of or long term.10 Therefore to improve the likeli- body. In many countries, are the sternum on any adult in apparent cardiac hood of bystander CPR, compression-only CPR still endorsed as the technique of choice (i.e. arrest. The patient should be placed supine remains the recommended technique for the the Heimlich manoeuvre). However, as this on a firm surface―such as a backboard, hard untrained rescuer or OHCA responder who is technique is associated with life-threatening mattress, or even the floor―to optimize the unable or unwilling to deliver rescue breaths. complications, such as intra-abdominal injury, it

3 1.1 BASIC LIFE SUPPORT is no longer recommended by the ARC or NZRC. randomized study showing superiority in terms Instead, the preferred technique for clearing an of neurological survival or survival to hospital Basic life support summary obstructed airway is by alternating back blows discharge. The five links in the Chain of Survival for a patient and/or chest thrusts. If a shock is not indicated, the rescuer should with sudden cardiac arrest include the following: immediately resume CPR at a 30/2 compression/ • Immediate recognition of the emergency Airway equipment ventilation ratio and wait for EMS to arrive or for and activation of help from the EMS system When cardiac arrest occurs in a medical facility, the victim to start responding. • Early CPR with an emphasis on chest com- simple airway equipment may be used as an pressions adjunct to EAR. This would include the use of a Automated external defibrillator • Earliest use of defibrillation simple face mask or bag-valve-mask ventilation The automated external defibrillator is now con- • Effective ALS with or without an oropharyngeal Guedel airway. sidered a part of BLS. AED devices are extremely • Integrated post-resuscitation care This equipment has the advantage of familiarity, accurate in diagnosing VF or VT. AEDs are Cardiac arrest may be presumed if the it decreases the risk of cross-infection, is aestheti- simple, safe and effective when used by either adult victim is unresponsive and not breathing cally more appealing and may deliver additional lay rescuers or health care professionals (in or normally (ignoring occasional gasps) without oxygen, but it does require prior training.8 out of hospital). assessing for a pulse. A trained rescuer may Whichever technique of assisted ventilation open the airway using the head tilt–chin lift is used, the adequacy of the tidal volume deliv- Lay rescuer/nonmedical personnel manoeuvre as part of the breathing assessment, ered over 1 second is assessed by a rise of the and public-access automated external but the lay/untrained rescuer should waste no victim’s chest. Current guidelines during adult defibrillator time in initiating chest compressions. Rescuers cardiac arrest support the use of the highest AEDs have been shown to be an effective part should activate the EMS system and start chest possible percentage of inspired oxygen during of the BLS program. Both ILCOR and ANZCOR compressions immediately. If a lone health CPR. However, any concentration of oxygen strongly recommend implementation of public- care rescuer responds to suspected asphyxia or during CPR is acceptable, the aim being to use access AED programs for patients with OHCA. respiratory-related cardiac arrest (e.g. immersion the maximum available concentration to correct AED use in public places such as airports, schools, or drowning), it is still reasonable for the health 8 tissue . sport facilities and recreation facilities by mini- care rescuer to provide 2 minutes of CPR before mally trained rescuers, untrained rescuers, police leaving the victim alone to activate EMS. Defibrillation officers or fire and disaster management first All rescuers, whether trained or not, should at As soon as a defibrillator is available, the elec- responders has achieved improved survival rates. least provide chest compressions to a victim of trode pads should be attached to the victim and Data from multiple observational, nationwide cardiac arrest, with a strong emphasis on deliv- the device switched on. Self-adhesive defibril- studies have shown improved rates of successful ering high-quality chest compressions. Trained lation pads have the practical advantages of defibrillator use and chances of survival through rescuers should also provide two rescue breaths being safe, convenient and effective; they are public-access AED programs. after each 30 chest compressions at a ratio of 30/2 increasingly preferred over handheld paddles. and deliver five cycles of 2 minutes each. The In all cases, the safety of the rescuers and other Home-access automated external compression rate should be approximately 100 team members remains paramount during the defibrillator to 120 per minute and a depth of at least 5 cm (or handling of defibrillators and shock delivery. Finally, an AED may be placed in the home of a 2 inches). All BLS guidelines encourage the use of patient who is at increased risk of sudden cardiac an AED by lay rescuers in cases of cardiac arrest, Shock delivery arrest (who does not have an implantable cardio- maintaining chest compressions while charging When using an automated external defibrillator, verter-defibrillator [ICD]) for use by a relative who the defibrillator to minimize any pre-shock pause. the rescuer follows the voice instructions, such might witness the event. However, home-access BLS care should be continued until advanced as ‘stand clear’ and ‘press the button’ to deliver AEDs are not associated with any improvement in help arrives and takes over CPR, the victim starts the shock if indicated. When using a manual survival rates. Therefore the use of such a device to respond or begins breathing normally, it is defibrillator, the health care rescuer must person- may be considered on an individual basis rather impossible for the rescuer to continue CPR (e.g. ally select the desired energy level and deliver a than as routine recommendation. exhaustion or safety compromise to rescuer) or shock after recognizing a shockable rhythm (VF a health care professional calls for the cessation or pulseless [VT]). Implantable cardioverter defibrillator and of CPR. cardiopulmonary resuscitation Minimizing interruptions to chest compres- Patients at highest immediate risk of unexpected CONTROVERSIES AND sions Irrespective of the resultant rhythm, cardiac arrest may have an ICD inserted which, KNOWLEDGE GAPS chest compressions must be resumed immedi- on sensing a shockable rhythm, will discharge • CPR to follow ABC or CAB sequence initially ately after each shock to minimize the ‘no-flow’ approximately 40 J through an internal pacing • Role of passive oxygenation and ventila- time. The interruption during chest compres- wire embedded in the right ventricle. Although tion in compression only CPR sions, including the preshock interval (for rhythm most patients with an implanted defibrillator • EMS bundled intervention care in OHCA analysis and shock delivery) and postshock remain conscious during defibrillation, CPR presenting in non-shockable rhythm interval (from shock delivery to resumption should be commenced if the patient fails to • Timing of CPR cycle and optimal interval of compressions), should be no more than 10 respond to the ICD counter shocks and becomes for rhythm check seconds. unconscious. Intermittent firing of the implanted • Value of pulse check while performing All modern defibrillators are now biphasic defibrillator presents no additional risk to CPR in BLS rather than monophasic and are more effec- bystanders or medical personnel. However, it is • Role of real-time audiovisual feedback tive in terminating ventricular at prudent to wear gloves and to minimize contact and prompt devices during CPR lower energy levels. However, there is still no with the patient while the device is discharging.

4 1.2 ADVANCED LIFE SUPPORT 1 RESUSCITATION 4. Iwami T, Kawamura T, Hiraide A, et al. Effectiveness out-of-hospital cardiac arrest. JAMA. 2008;299:1158–1165. References of bystander-initiated cardiac-only resuscitation for https://doi.org/10.1001/jama.299.10.1158. patients with out-of-hospital cardiac arrest. Circulation. 8. Hoke RS, Heinroth K, Trappe HJ, Werdan K. Is external 1. Cummins RO, Ornato JP, Thies WH, Pepe PE. Improving 2007;116:2900–2907. https://doi.org/10.1161/CIRCULATIO- defibrillation an electric threat for bystanders? Resuscita- survival from sudden cardiac arrest: the ‘Chain of Sur- NAHA.107.723411. tion. 2009;80:395–401. vival’ concept. A statement for health professionals from 5. Bobrow BJ, Spaite DW, Berg RA, et al. Chest 9. Mitani Y, Ohta K, Yodoya N, et al. Public access defibrilla- the Advanced Cardiac Life Support Subcommittee and compression-only CPR by lay rescuers and survival from tion improved the outcome after out-of-hospital cardiac the Emergency Cardiac Care Committee, American Heart out-of-hospital cardiac arrest. JAMA. 2010;304:1447–1454. arrest in school-age children: a nationwide, population- Association. Circulation. 1991;83(5):1832–1847. https://doi.org/10.1001/jama.2010.1392. based, Utstein registry study in Japan. Europace. 2013; 2. 2015 International Consensus on Cardiopulmonary Resus- 6. Bobrow BJ, Ewy GA, Clark L, et al. Passive oxygen 15:1259–1266. https://doi.org/10.1093/europace/eut053. citation and Emergency Cardiovascular Care Science with insufflation is superior to bag-valve-mask ventilation for 10. Weisfeldt ML, Sitlani CM, Ornato JP, et al. Survival after Treatment Recommendations. Circulation. 2015;132:S1–S311. witnessed ventricular fibrillation out-of-hospital cardiac application of automatic external defibrillators before 3. Sasson C, Rogers MA, Dahl J, Kellermann AL. Predictors arrest. Ann Emerg Med. 2009;54:656–662.e1. https://doi. arrival of the emergency medical system: evaluation in of survival from out-of-hospital cardiac arrest: a sys- org/10.1016/j.annemergmed.2009.06.011. the resuscitation outcomes consortium population of 21 tematic review and meta-analysis. Circ Cardiovasc Qual 7. Bobrow BJ, Clark LL, Ewy GA, et al. Minimally interrupted million. J Am Coll Cardiol. 2010;55:1713–1720. https://doi. Outcomes. 2010;3(1):63–81. cardiac resuscitation by emergency medical services for org/10.1016/j. jacc.2009.11.077.

1.2 Advanced life support Sameer A. Pathan

patient survival. ALS involves the continuation ESSENTIALS of BLS as necessary, but with the additional use basic or advanced airway devices, vascular 1 Follow the Advanced Life Support (ALS) resuscitation guidelines developed by, or access techniques, and the administration of based on, those of the International Liaison Committee on Resuscitation (ILCOR). pharmacological agents. 2 Perform chest compressions without interruption for patients with no pulse, except when performing essential ALS interventions. Aetiology and incidence of cardiac arrest 3 Deliver a shock to attempt defibrillation (150–200 joules [J] biphasic or 360 J monophasic) if the rhythm is either ventricular fibrillation (VF) or pulseless ventricular The commonest cause of sudden cardiac arrest tachycardia (VT). in adults is ischaemic heart disease.3 Other causes include , drug overdose, meta- 4 Institute other ALS interventions as indicated. bolic derangements, trauma, hypovolaemia, immersion and . 5 Correct reversible causes of cardiac arrest the ‘4 Hs and 4 Ts’. ― The incidence of out-of-hospital cardiac arrest 6 Implement a comprehensive, structured post-resuscitation treatment protocol. (OHCA) recorded in Aus-ROC Epistry was 102.5 cases per 100,000 population.4 The crude inci- dence of OHCA in New Zealand was noted as 124 cases per 100,000 person-year. In both studies, 12% to 15% of cases with attempted resuscitation Introduction Chain of Survival survived to hospital discharge or 30 days. A patient in cardiac arrest represents the most The importance of rapid treatment for cardiac time-critical medical crisis an emergency physi- arrest led to the development of a systems man- cian manages. The interventions of Basic Life agement approach, represented by the concept Advanced Life Support guidelines Support (BLS) and Advanced Life Support (ALS) of a ‘Chain of Survival’, which has become the and algorithms have the highest probability of success when accepted model for emergency medical services The most clinically relevant advance in ALS, over applied immediately; they become less effective (EMS).2 This concept implies that more people the last two decades has been the substantial with the passage of time and, after only a short survive sudden cardiac arrest when a cluster simplification of the management of cardiac interval without treatment, are ineffectual.1 or sequence of events is activated as rapidly arrest by the development of widely accepted Larsen et al., in 1993, calculated the time as possible. The Chain of Survival includes the universal guidelines and algorithms that include intervals from collapse to the initiation of BLS, following: evidence-based recommendations. defibrillation, and other ALS treatments and ana- • Early access to EMS and cardiac arrest lysed their effect on survival after out-of-hospital ­prevention International Liaison Committee on cardiac arrest. When all three interventions were • Early high-quality cardiopulmonary resusci- Resuscitation immediately available, the survival rate was 67%. tation (CPR) In Chapter 1.1, Box 1.1.1 shows the national asso- This figure declined by 2.3%/min of delay to BLS, • Early defibrillation ciations that formed the International Liaison by a further 1.1%/min of delay to defibrillation, • Early advanced care and post-resuscitation Committee on Resuscitation (ILCOR) in 1993. and by 2.1%/min to other ALS interventions. care The ILCOR group used to meet every 5 years to Without treatment, the decline in survival rate is All the links in the chain must connect, as review the best available scientific literature and the sum of the three, or 5.5%/min. weakness in any one reduces the probability of to publish the Consensus on Cardiopulmonary 5