implemented at all sites. Survival was double at AED sites compared to non‐AED sites [23]. Other reports also describe successful public‐access defibrillation programs [51].
In Japan, public‐access defibrillators became rapidly available starting in 2004 [52, 53]. The cumulative number of public‐access defibrillators (excluding medical facilities and EMS institutions) increased from 9,906 in 2005 to 297,095 in 2011 [54]. From 2005 to 2007, the proportion of bystander‐witnessed VF/VT arrest victims who received public‐access defibrillation increased from 1.2% (45/3841) to 6.2% (274/4402) [52]. 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 [55]. A related innovation is the wearable cardioverter‐defibrillator, which combines a long‐term ECG monitoring system with an external automatic defibrillator [56].
Locations at high risk can be identified using public health surveillance tools such as registries that collect standardized data about 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 [57, 58]. These should have emergency preparedness and response plans that include AED deployment [59–61]. Such 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 public‐access defibrillation 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 public‐access defibrillation programs. Several web sites and publications provide detailed suggestions for public‐access defibrillation program development [62–65].
First‐Responder and Basic Life Support Care
Before the advent of public‐access defibrillation, EMS 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 advanced life support (ALS) ambulance could. The first important report of this concept involved firefighter first‐responders in King County, Washington in 1989 [65]. Police first‐responders in Rochester, Minnesota and suburban areas near Pittsburgh, Pennsylvania successfully used AEDs [19,66–68]. 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 [68]. The use of motorcycles in urban settings to reduce response time has also been described [69].
The OPALS study specifically evaluated the effect of optimizing time to defibrillation by basic life support (BLS) responders, with a goal of having a defibrillator‐equipped vehicle on scene within 8 minutes of 9‐1‐1 call receipt for 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% [70]. A subsequent analysis found that increasing time to defibrillation was associated with decreased survival (Figure 12.4) [1]. 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. Research indicates that the quality of CPR is vitally important, especially rate, depth, and reducing prolonged interruption of chest compressions, as interruptions result in less cycle time and lower coronary perfusion pressures [5771–75]. Deploying multiple first‐responders (teams of four or more) to enable closely supervised BLS has also been advocated as “high‐performance CPR.” Also, use of mechanical CPR has been recommended, especially if transport with on‐going CPR is needed, for example in BLS ambulance systems [76], though data showing a survival benefit to mechanical CPR are lacking.
Figure 12.4 Predicted survival versus defibrillation response interval.
Source: De Maio VJ, Stiell IG, Wells GA, and Spaite DW. Optimal defibrillation response intervals for maximum out‐of‐hospital cardiac arrest survival rates. Ann Emerg Med. 2003; 42(2):242–50. Reproduced with permission from Elsevier.
Basic Life Support
The 2015 ILCOR Consensus on Science with Treatment Recommendations re‐emphasized the findings of the 2010 reviews [77]. It confirmed the importance of high‐quality CPR commencing as soon as cardiac arrest has been recognized. It referenced multiple studies that found no differences in neurologic outcomes or mortality between compression‐only and conventional high‐quality CPR but recommended that first‐responders should perform ventilations if trained and willing. It similarly re‐emphasized the importance of components such as compression rate between 100 and 120/min, noting lower survival when rates were faster. It emphasized a depth of 5 cm or 2 inches, the need for adequate chest recoil, and the need for a high as possible chest compression fraction [78].
As with many other facets of resuscitation, the COVID‐19 pandemic has significantly altered some of these recommendations, as the risk of coronavirus infection has increased the risk of some interventions (Figure 12.5). In Seattle, COVID‐19 was diagnosed in fewer than 10% of patients with OHCA and investigators estimated that, with an approximate 1% mortality rate for COVID‐19, approximately 1 rescuer in 10,000 bystander CPR events might die from the disease, compared with over 300 lives/10,000 events saved by the CPR [79].
Although older lay rescuers are more vulnerable to infection with SARS‐CoV‐2 and are unlikely to have access to adequate personal protective equipment (PPE), new guidelines state that if the cardiac arrest occurs at home, as the majority do, lay rescuers are likely to have already been exposed to COVID‐19 [80]. It is recommended that compression‐only CPR be delivered by lay rescuers, with a facemask or cloth covering the mouth and nose of the rescuer and the patient. Rescue breaths are still recommended for pediatric cardiac arrests, if the lay rescuers are household members who have been exposed to the patient at home. Lay rescuers should follow instructions given by the 9‐1‐1 telecommunicator [81].
The June 2020 consensus statement from the Emergency Cardiovascular Care Committee and Get With The Guidelines‐Resuscitation Adult and Pediatric Task Forces of the AHA stated that, “Before entering the scene, all rescuers should don PPE to guard against contact with both airborne and droplet particles,” and that personnel in the room or on the scene should be limited to those “essential for patient care” [80]. Hand hygiene should be performed before and after all patient contact, putting on and after removing PPE (including gloves), and contact with potentially infectious material [82].
The diagnosis of cardiac arrest still relies on the combination of unresponsiveness and an absence of normal breathing. Instead of opening the airway, and looking, listening, and feeling for breathing with the rescuer’s face close to the patient’s mouth and nose, it is recommended that rescuers place a hand on patient’s chest to feel for chest rise and fall while assessing for normal breathing [83].