IV-38 Circulation December 13, 2005 emphasized the importance of organization, planning, train- AEDs are of no value for arrest not caused by vF/pulseless ing, linking with the EMS system, and establishing a process VT, and they are not effective for treatment of nonshockable of continuous quality improvement. 50,51 rhythms that may develop after termination of VF. Nonper Studies of lay rescuer AED programs in airports52 and fusing rhythms are present in most patients after shock casinos53.54 and first-responder programs with police offi- delivery, 5. 26. 28.44 and CPR is required until a perfusing cers26,3436.44.55-57 have shown a survival rate of 41% to 74% rhythm returns. Therefore, the AEd rescuer should be trained from out-of-hospital witnessed VF SCA when immediate not only to recognize emergencies and use the AED but also bystander CPR is provided and defibrillation occurs within to support ventilation and circulation with CPR as needed. about 3 to 5 minutes of collapse. These high survival rates, The mere presence of an AEd does not ensure that it will however, are not attained in programs that fail to reduce time be used when SCA occurs Even in the NHLBI trial, in which to defibrillation, 58-60 almost 20 000 rescuers were trained to respond to SCA, lay In a large prospective randomized trial (LOE 1)6l funded rescuers attempted resuscitation before EMS arrival for only (NHLBI, and several aeD manufacturers, lay rescuer CPR was used for only 34% of the victims who experience o by the AHA, the National Heart, Lung, and Blood Institute half of the victims of witnessed SCA, and the on-site Al Aed programs in targeted public settings doubled the arrest at locations with AED programs. b These findings number of survivors from out-of-hospital VF SCA when ggest that lay rescuers need frequent practice to optimize compared with programs that provided early EMS call and response to emergencies early CPR. The programs included a planned response, lay ment processes of continuous quality improvement(Class ing elements are recommended for community lay rescuer routine inspections and postevent data(from AED recordings AED programs and responder reports) to evaluate the following 50,51 A planned and practiced response; typically this requires Performance of the emergency response plan, including oversight by a healthcare provider accurate time intervals for key interventions (such as Training of anticipated rescuers in CPR and use of the AED collapse to shock or no shock advisory to initiation of Link with the local EMS system CPR), and patient outcome Process of ongoing quality improvement Responder performance More information is available on the aha website: www AED function, including accuracy of the ECG rhythm Under the topic "Links on this site, analysis Battery status and function Lay rescuer AED programs will have the greatest potentia impact on survival from SCA if the programs are created locations where SCA is likely to occur. In the NHLBI trial, Automated Rhythm Analysis programs were established at sites with a history of at least I AEDs have microprocessors that analyze multiple features of out-of-hospital cardiac arrest every 2 years or where at least the surface ECG signal, including frequency, amplitude, and I out-of-hospital SCA was predicted during the study period some integration of frequency and amplitude, such as slope or (ie, sites having >250 adults over 50 years of age present for wave morphology. Filters check for QRS-like signals, radio >16hd).61 transmission, or 50-or 60-cycle interference as well as loose To be effective, AED programs should be integrated into electrodes and poor electrode contact. Some devices are an overall EMS strategy for treating patients in cardiac arrest. programmed to detect spontaneous movement by the patient CPR and AED use by public safety first responders(tradi or others. Prototype defibrillators were used in 2 recent witnessed cardiac arrest(eg, airports, casinos, sports facili- providea, mpt resaa9al tional and nontraditional) are recommended to increase sur- clinical trials evaluating quality of CPr in the out-of-hospital vival rates for SCA(Class I). AED programs in public and hospital settings, and they hold promise for future AEDs locations where there is a relatively high likelihood of that may the quality of CF ties)are recommended( Class I). Because the improvement in AEDs have been tested extensively, both in vitro against survival rates in aED programs is affected by the time to libraries of recorded cardiac rhythms and clinically in many CPR and to defibrillation, sites that deploy AEDs should field trials in adultsb3, 6 and children. os. 6 They are extremely establish a response plan, train likely responders in CPR and accurate in rhythm analysis. Although AEDs are not designed AED use, maintain equipment, and coordinate with local to deliver synchronized shocks(ie, cardioversion for VT with EMS systems pulses), AEDs will recommend a(nonsynchronized) shock Approximately 80% of out-of-hospital cardiac arrests oc- for monomorphic and polymorphic VTif the rate and r-wave cur in private or residential settings (LOE 4).62 Reviewers morphology exceed preset values found no studies that documented the effectiveness of home Electrode placement AED deployment, so there is no recommendation for or Rescuers should place AED electrode pads on the victim' against personal or home deployment of AEDs(Class bare chest in the conventional sternal-apical(anterolateral) position(Class Ia). The right(sternal)chest pad is placed onemphasized the importance of organization, planning, train￾ing, linking with the EMS system, and establishing a process of continuous quality improvement.50,51 Studies of lay rescuer AED programs in airports52 and casinos53,54 and first-responder programs with police offi￾cers26,34,36,44,55–57 have shown a survival rate of 41% to 74% from out-of-hospital witnessed VF SCA when immediate bystander CPR is provided and defibrillation occurs within about 3 to 5 minutes of collapse. These high survival rates, however, are not attained in programs that fail to reduce time to defibrillation.58–60 In a large prospective randomized trial (LOE 1)61 funded by the AHA, the National Heart, Lung, and Blood Institute (NHLBI), and several AED manufacturers, lay rescuer CPR AED programs in targeted public settings doubled the number of survivors from out-of-hospital VF SCA when compared with programs that provided early EMS call and early CPR. The programs included a planned response, lay rescuer training, and frequent retraining/practice. The follow￾ing elements are recommended for community lay rescuer AED programs50,51: ● A planned and practiced response; typically this requires oversight by a healthcare provider ● Training of anticipated rescuers in CPR and use of the AED ● Link with the local EMS system ● Process of ongoing quality improvement More information is available on the AHA website: www. americanheart.org/cpr. Under the topic “Links on this site,” select “Have a question?” and then select “AED.” Lay rescuer AED programs will have the greatest potential impact on survival from SCA if the programs are created in locations where SCA is likely to occur. In the NHLBI trial, programs were established at sites with a history of at least 1 out-of-hospital cardiac arrest every 2 years or where at least 1 out-of-hospital SCA was predicted during the study period (ie, sites having
250 adults over 50 years of age present for
16 h/d).61 To be effective, AED programs should be integrated into an overall EMS strategy for treating patients in cardiac arrest. CPR and AED use by public safety first responders (tradi￾tional and nontraditional) are recommended to increase sur￾vival rates for SCA (Class I). AED programs in public locations where there is a relatively high likelihood of witnessed cardiac arrest (eg, airports, casinos, sports facili￾ties) are recommended (Class I). Because the improvement in survival rates in AED programs is affected by the time to CPR and to defibrillation, sites that deploy AEDs should establish a response plan, train likely responders in CPR and AED use, maintain equipment, and coordinate with local EMS systems.50,51 Approximately 80% of out-of-hospital cardiac arrests oc￾cur in private or residential settings (LOE 4).62 Reviewers found no studies that documented the effectiveness of home AED deployment, so there is no recommendation for or against personal or home deployment of AEDs (Class Indeterminate). AEDs are of no value for arrest not caused by VF/pulseless VT, and they are not effective for treatment of nonshockable rhythms that may develop after termination of VF. Nonper￾fusing rhythms are present in most patients after shock delivery,25,26,28,44 and CPR is required until a perfusing rhythm returns. Therefore, the AED rescuer should be trained not only to recognize emergencies and use the AED but also to support ventilation and circulation with CPR as needed. The mere presence of an AED does not ensure that it will be used when SCA occurs. Even in the NHLBI trial, in which almost 20 000 rescuers were trained to respond to SCA, lay rescuers attempted resuscitation before EMS arrival for only half of the victims of witnessed SCA, and the on-site AED was used for only 34% of the victims who experienced an arrest at locations with AED programs.61 These findings suggest that lay rescuers need frequent practice to optimize response to emergencies. It is reasonable for lay rescuer AED programs to imple￾ment processes of continuous quality improvement (Class IIa). These quality improvement efforts should use both routine inspections and postevent data (from AED recordings and responder reports) to evaluate the following50,51: ● Performance of the emergency response plan, including accurate time intervals for key interventions (such as collapse to shock or no shock advisory to initiation of CPR), and patient outcome ● Responder performance ● AED function, including accuracy of the ECG rhythm analysis ● Battery status and function ● Electrode pad function and readiness, including expiration date Automated Rhythm Analysis AEDs have microprocessors that analyze multiple features of the surface ECG signal, including frequency, amplitude, and some integration of frequency and amplitude, such as slope or wave morphology. Filters check for QRS-like signals, radio transmission, or 50- or 60-cycle interference as well as loose electrodes and poor electrode contact. Some devices are programmed to detect spontaneous movement by the patient or others. Prototype defibrillators were used in 2 recent clinical trials evaluating quality of CPR in the out-of-hospital and hospital settings, and they hold promise for future AEDs that may prompt rescuers to improve the quality of CPR provided.18,19 AEDs have been tested extensively, both in vitro against libraries of recorded cardiac rhythms and clinically in many field trials in adults63,64 and children.65,66 They are extremely accurate in rhythm analysis. Although AEDs are not designed to deliver synchronized shocks (ie, cardioversion for VT with pulses), AEDs will recommend a (nonsynchronized) shock for monomorphic and polymorphic VT if the rate and R-wave morphology exceed preset values. Electrode Placement Rescuers should place AED electrode pads on the victim’s bare chest in the conventional sternal-apical (anterolateral) position (Class IIa). The right (sternal) chest pad is placed on IV-38 Circulation December 13, 2005