Bystander recognition of arrest and calling for help

The most important first steps in cardiac arrest care are recognition of the event and summoning help. These actions require widespread public awareness of the existence of OHCA, how to recognize OHCA, and the importance of immediate action.

The methods for teaching laypersons the recognition of OHCA have evolved over recent years. Many studies have described the difficulty of and delays caused by laypersons attempting to feel for a pulse [29]. One showed that even trained EMTs were inaccurate in detecting the presence or absence of a pulse in patients undergoing cardiac bypass during open heart surgery [30]. Thus, current American Heart Association (AHA) guidelines advise that bystanders should call 9-1-1 and begin treatment for OHCA if the person has no movement and no regular breathing. Bystanders must not mistake agonal gasps for normal breathing [31].

Emergency medical dispatch (EMD) is essential in cardiac arrest care. Dispatch centers must quickly and accurately recognize potential cardiac arrest calls and promptly dispatch appropriate first responder and EMS units. Providing prearrival instructions for bystander CPR and AED use is another important EMD role. Dispatcher instruction in CPR improves the likelihood of the caller performing CPR [32]. The details and requirements for emergency dispatching systems are discussed in Volume 2, Chapter 10.

Bystander cardiopulmonary resuscitation

Bystander CPR refers to CPR performed by someone who was already present at or passing by the location of the patient. This contrasts with CPR performed by dispatched emergency responders. Bystanders have the earliest opportunity to provide CPR to the cardiac arrest victim. Multiple studies have demonstrated the survival benefit of bystander CPR as well as the increase in mortality with delays in CPR delivery [33,34].EMS medical directors and agencies should monitor and optimize the rate of bystander CPR in their communities [35]. Prior efforts have included community education about OHCA and the importance of CPR, increasing access to training, and teaching CPR in schools to develop a culture of bystander assistance.

When callers do not know CPR, the dispatcher should provide real-time instructions over the phone. Most current EMD protocols detail specific CPR instructions [36]. Growing evidence suggests that properly performed chest compressions are more important than ventilations [37–39]. Most emergency dispatch protocols now favor providing instructions only for chest compressions.

The AHA recommends that bystanders not trained in CPR and those trained but not confident or willing to perform ventilations should perform chest compression-only CPR until a defibrillator is ready for use (Class IIa) [37]. Unrecognized fatigue is common after just 1–2 minutes, so bystanders providing chest compressions should switch frequently [40].

Public access defibrillation

The most important cardiac arrest interventions for patients in VF or VT are early chest compressions and defibrillation. Although 70–80% of VF can be successfully converted to a perfusing rhythm if shocked within 3 minutes of VF onset, this success rate deteriorates rapidly with each additional minute [41]. Survival decreases 7–10% for each minute that passes before defibrillation [34] (Figure 11.1).

Automated external defibrillators provide lay bystanders with the ability to deliver rescue shocks. These devices were first used clinically in 1979 to recognize and deliver rescue shocks for VF and rapid VT [42]. AEDs are automated and simple to use with visual and audible instructions for operating the defibrillator and initiating CPR. They are relatively inexpensive and extremely safe; modern AEDs do not allow delivery of inappropriate shocks [43]. Most are equipped with memory modules that can record the entire resuscitation event, including continuous ECG and audio recording.

Defibrillators with CPR feedback use accelerometers embedded within chest defibrillation pads to measure depth and rate of compression, or use variations in chest impedance to reflect chest wall movements [44,45]. These devices are able to give verbal as well as visual prompts to cue the rescuer to speed up, slow down, or increase the depth of compressions or ventilations [46]. Such devices have been shown to improve the quality of CPR for out-of-hospital [47] as well as in-hospital cardiac arrest [46].

A variety of AED models are now available, ranging in sophistication and ruggedness. Some models are designed for minimally trained lay bystanders, and are available for consumer purchase without physician prescription.

There is strong scientific evidence confirming the efficacy of early first responder, bystander, and public access defibrillation. A trial which trained security personnel in casinos to recognize OHCA, start CPR, and use on-site AEDs achieved 53% survival from VF, and among patients shocked within 3 minutes survival was 74% [23]. AEDs have also been successfully used on aircraft and in the airport [48]. In the multicenter PAD trial, 993 high-risk locations were randomized to deploy or not deploy on-site AEDs. A response plan with identification and training of on-site responders was implemented at all sites. Survival was double at AED sites compared to non-AED sites [22]. Other reports also describe successful PAD programs [49].

One successful real-world example is Japan, where public access defibrillators have rapidly become more available since 2004 [50,51]. The cumulative number of public access defibrillators (excluding medical facilities and EMS institutions) increased from 9,906 in 2005 to 297,095 in 2011 [52]. From 2005 to 2007, the proportion of bystander-witnessed VF/VT arrests who received public access defibrillation increased from 1.2% (45/3841) to 6.2% (274/4402) [50]. The latest data show that over 40% of cardiac arrests in public places like train stations and sports facilities received shocks with public access defibrillators.

The observation that a majority of OHCA events occur in residential settings raised interest in home deployment of AEDs. This concept was evaluated in a large, multicenter, international trial of anterior wall myocardial infarction survivors who were not candidates for implantable cardiac defibrillators [53]. A related innovation is the wearable cardioverter-defibrillator, which combines a long-term ECG monitoring system with an AED [54].

Locations at high risk can be identified using public health surveillance tools such as registries that collect standardized data on OHCA. Cardiac arrest locations can be analyzed using geographic information systems and spatial epidemiology methods to identify and target high-risk neighborhoods within a community [55,56]. These should have emergency preparedness and response plans that include AED deployment [57–59]. These areas may include airports, fitness centers, large workplaces, arenas and convention centers, and even jails. AED deployment and response plans should include registration with dispatch centers, development of a notification system to alert on-site responders, selection and training of responders, and deployment of appropriate AED and other rescue equipment. Equipment maintenance, annual response plan review, and quality improvement incident reviews are essential components of an effective PAD program. Smartphone apps are also available which can show the location of the nearest AED during an emergency. These can be integrated into local response systems.

There is an important opportunity for local EMS agencies and medical directors to assist public and private sites with implementing PAD programs. Several websites and publications provide detailed suggestions for PAD program development [60–72].

First responder and Basic Life Support care

Before the advent of PAD, medical directors sought ways to shorten the delays to initial defibrillation.One solution was to equip first responders with AEDs because these individuals could often reach a cardiac arrest victim faster than an ALS ambulance. The first important report of this concept involved firefighterfirst responders in King County, Washington, in 1989 [73]. Police first responders in Rochester, Minnesota, and suburban areas near Pittsburgh, Pennsylvania, also successfully used AEDs [19,74,75]. These programs demonstrated benefit even if the first responders arrived only 2 minutes before EMS. Cardiac arrest survival was 50% in Rochester, Minnesota, after introducing a police AED program [75,76]. The use of motorcycles in urban settings to reduce response time has also been described [77].

The OPALS study specifically evaluated the effect of optimizing time to defibrillation by BLS responders, with a goal of having a defibrillator-equipped vehicle on scene within 8 minutes of 9-1-1 call receipt in 90% of calls. Increasing the proportion of responses that met the 8-minute standard from 77% to 92% improved survival to hospital discharge from 3.9% to 5.2% [78]. A subsequent analysis found that increasing time to defibrillation was associated with decreased survival [1] (Figure 11.2). These observations further underscored the greater importance of bystander action in facilitating additional survival.

Performing high-quality, continuous chest compressions is another important role for first responders. There is increasing evidence of the role of high-quality chest compressions in improving defibrillation success [79–81]. Research indicates that the quality of CPR is vitally important [54,80], especially rate, depth, and reducing prolonged interruption of chest compressions, as interruptions result in less cycle time and lower coronary perfusion pressures [74–77]. Use of multiple first responders (teams of four or more) to allow for closely supervised BLS has also been advocated as “high-performance CPR.” Also, use of mechanical CPR has been recommended, especially if transport with ongoing CPR is needed, for example in BLS ambulance systems [78].

Advanced Life Support care

Although traditionally viewed as the cornerstone of cardiac arrest care, the limited effectiveness of traditional ALS interventions in cardiac arrest is increasingly being shown. In the OPALS study, which added ALS care to previously optimized first responder defibrillation, ALS care did not further improve cardiac arrest survival [2]. In other words, early CPR and defibrillation had greater effects on cardiac arrest survival than advanced airway management or drug administration.

In the systematic and comprehensive evidence review undertaken for the production of the International Liaison Committee on Resuscitation (ILCOR) guidelines in 2010, many ALS interventions previously accepted as routine were found to be supported by little good-quality evidence. ILCOR Consensus on Science authors stated that there were no data to support the routine use of any specific approach to airway management during cardiac arrest, and elaborated on concerns that extended attempts to insert an endotracheal tube may lead to harmful interruption of chest compressions [82].

They concluded that there was insufficient evidence to define the optimal timing of advanced airway placement during cardiac arrest, and also stated that supraglottic airway devices may be considered by health care professionals trained in their use as an alternative to bag-valve-mask ventilation during CPR. Cricoid pressure was not recommended for use in cardiac arrest, whereas waveform capnography was. A lack of evidence supporting many ALS pharmacological interventions was emphasized, including vasopressors, atropine, steroids, fibrinolytics, and fluids during cardiac arrest, with placebo-controlled trials being called for; calcium and sodium bicarbonate were not recommended [82].

Since 2010, studies have continued to show that advanced airway management during cardiac arrest appears not to benefit patients. A prospective, population-based study in Japan involving 650,000 out-of-hospital cardiac arrest patients showed that any type of advanced airway management was independently associated with decreased odds of neurologically favorable survival compared with conventional bag-valve-mask ventilation [83].

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