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A national scheme for public access defibrillation in England and Wales: Early results
Resuscitation (2008) 78, 275—280
available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/resuscitation
CLINICAL PAPER
A national scheme for public access defibrillation in England and Wales: Early results夽 M.C. Colquhoun a,b,c,∗, D.A. Chamberlain a,b, R.G. Newcombe a, R. Harris c, S. Harris c, K. Peel d, C.S. Davies e, R. Boyle e a
Department of Primary Care and Public Health, (Medical Statistics), School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, United Kingdom b Prehospital Emergency Research Unit, School of Medicine, Cardiff University, Lansdowne Hospital, Sanitorium Road, Cardiff CF11 8PL, United Kingdom c The Resuscitation Council (UK), 5th Floor, Tavistock House North, Tavistock Square, London WC1H 9HR, United Kingdom d The British Heart Foundation, 14 Fitzhardinge Street, London W1H 6DH, United Kingdom e Department of Health, Wellington House (Level 4), 133-155 Waterloo Road, London SE1 8UG, United Kingdom Received 10 February 2008; received in revised form 15 March 2008; accepted 24 March 2008
KEYWORDS Defibrillation; Public access defibrillation; Automated external defibrillator
Summary Background: Automated external defibrillators (AEDs) operated by lay persons are used in the UK in a National Defibrillator Programme promoting public access defibrillation (PAD). Methods: Two strategies are used:(1) Static AEDs installed permanently in busy public places operated by those working nearby. (2) Mobile AEDs operated by community first responders (CFRs) who travel to the casualty. Results: One thousand five hundred and thirty resuscitation attempts. With static AEDs, return of spontaneous circulation (ROSC) was achieved in 170/437 (39%) patients, hospital discharge in 113/437 (26%). With mobile AEDs, ROSC was achieved in 110/1093 (10%), hospital discharge in 32 (2.9%) (P < 0.001 for both variables).More shocks were administered with static AEDS 347/437 (79%) than mobile AEDs 388/1093 (35.5%) P < 0.001. Highly significant advantages existed for witnessed arrests, administration of shocks, bystander CPR before arrival of AED and short delays to start CPR and attach AED. These factors were more common with static AEDs. For CFRs, patients at home did less well than those at other locations for ROSC (P < 0.001) and survival (P = .006). Patients at home were older, more arrests were unwitnessed, fewer shocks were given, delays to start CPR and attach electrodes were longer.
夽 A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2008.03.226. ∗ Corresponding author at: Department of Primary Care and Public Health, (Medical Statistics), School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, United Kingdom. Tel.: +44 29 2093 2903. E-mail address: [email protected] (M.C. Colquhoun).
0300-9572/$ — see front matter © 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2008.03.226
276
M.C. Colquhoun et al. Conclusions: PAD is a highly effective strategy for patients with sudden cardiac arrest due to ventricular fibrillation who arrest in public places where AEDs are installed. Community responders who travel with an AED are less effective, but offer some prospect of resuscitation for many patients who would otherwise receive no treatment. Both strategies merit continuing development. © 2008 Elsevier Ireland Ltd. All rights reserved.
Introduction The use of automated external defibrillators (AEDs) by lay persons who are not professional health care providers, (‘public access defibrillation’, PAD) has proved an effective strategy in the management of sudden cardiac arrest occurring outside hospital.1—10 Delays in performing defibrillation can be appreciably reduced if those nearby can use an AED before the arrival of the emergency medical services. Most reports of PAD have described the use of AEDs made available in public places where the possibility of cardiac arrests can be foreseen and where lay persons working in the vicinity can be trained to use them.1—5,7,10 This is sometimes termed the ‘static AED’ or ‘on-site’ strategy.10,11 The alternative ‘mobile’ strategy for PAD employs lay volunteers as ‘community first responders’ (CFRs) dispatched by ambulance control centres because they can reach a victim sooner than a conventional ambulance. In some areas of the United Kingdom (UK) members of the fire and police services also act in this role. Such community first responders are not limited to specific sites. They may provide the best option for treating patients at home, the commonest place for cardiac arrest to occur.12—14 In England and Wales, PAD developed during the 1990s principally through the provision of AEDs driven by the British Heart Foundation (BHF), the UK’s leading heart charity. This was to equip not only locations where the ‘on-site’ strategy was planned but also community first responders (FRs) for the mobile strategy planned in association with ambulance services. Later, the Government, through the Department of Health (DH), made PAD a core part of the National Health Service (NHS) in England by placing 700 AEDs at high risk locations.15 These complemented AEDs already installed at other public sites or used by community first responder schemes. Subsequently, the BHF was awarded a national lottery grant and joined forces with the Department of Health to coordinate the expansion of both PAD strategies throughout England through a National Defibrillator Programme (NDP). The Welsh Assembly Government and the BHF later established similar arrangements in Wales. This paper describes the largest series of resuscitation attempts reported to date within an evolving PAD programme and is based on nationwide statistics. We report the effectiveness of defibrillation by lay persons and the relative effectiveness of different PAD strategies used in the UK.
Methods The establishment of the National Defibrillator Programme, methods of data collection and standard report form used are described in detail elsewhere.16,17 The cost of
AEDs, related equipment, training and administration was provided by the NHS, the BHF, and a national lottery fund. (a) ‘On-site’ defibrillators The DH placed AEDs in busy public places identified from routine ambulance data as sites where cardiac arrest was liable to occur such as airports and major railway stations. AEDs are kept in unlocked protective cabinets within 200 m walking distance from any part of the premises to which the public has access. Staff working at these sites volunteered to be trained over 4 h to provide basic life support (BLS) and to use an AED. A standardized competency-based curriculum with adequate manikin practice is supplemented by simulated cardiac arrest scenarios. Most training is provided by the statutory ambulance services. Similar arrangements were adopted by other organizations in sports facilities, workplaces, shopping centres and exhibition halls; these AEDs were usually funded by the BHF. At major sporting venues, members of the voluntary societies such as St John Ambulance and the Red Cross attend during events with one or more AEDs. (b) ‘‘Mobile’ defibrillators with community first responders Ambulance services train and equip lay community first responders to provide a service in the areas they administer. Dispatch is by ambulance control centres in response to emergency calls from the public. This strategy is commonly used in rural areas where ambulance response times are necessarily long. Police and fire services coordinate their own training, usually in conjunction with the local ambulance service. Deployment is by ambulance control centres or the control centre for the organization concerned.
Data collection and statistical analysis Data are recorded at the location on a report form compatible with the Utstein system for uniform recording of prehospital resuscitation attempts.18 The intervals between collapse and both the institution of basic life support and attachment of AED pads are usually estimated, but are sometimes supported by data from ambulance or other control systems. The interval from collapse to placement of pads allows a comparison of time to treatment for patients with and without shockable rhythms. Data from report forms were entered into a Microsoft Access database, and subsequently into SPSS v 12.0.2 for statistical analysis. Comparisons were made between groups A and B and between groups B and C as defined below, using chi-square tests for binary variables such as sex or survival, and Mann—Whitney tests for continuous variables
13((1.6)
viz. age and delays to start of CPR and AED pad placement.
Results This report is based on 1530 resuscitation attempts initiated by lay persons equipped with an AED from 11th March 1999 to 31st December 2005. Shocks were administered to 735 (48%) victims, with return of spontaneous circulation (ROSC) in 245 of them (33%). One hundred and thirty-two (18%) of those who received shocks were discharged alive from hospital. Outcome was poor among 795 unshocked patients, with 35 (4.4%) attaining ROSC and 13 (1.6%) surviving. Important differences in patient characteristics and outcome were apparent between patients treated ‘on-site’ (group A) and those treated by community first responders using the mobile strategy; among the latter category there were further important differences between patients treated outside the home (group B) and those treated at home (group C). The principal differences are shown in Table 1.
132((18.0)
Sex One thousand one hundred and twenty-four (74.7%) of 1504 victims whose sex was recorded were male. A higher proportion of males than females were shocked (53.2% vs. 31.1%, P < 0.001), achieved ROSC (20.4% vs. 11.8%, P < 0.001) and survived (10.8% vs. 4.2%, P < 0.001). Among patients who received shocks, however, similar proportions of the two sexes achieved ROSC (M 33.8% vs. F 31.4%, P = .61) with no significant difference in survival (M 18.6% vs. F 12.7%, P = .13).
1124((74.7)
735((48.0) 245((33.3)
795((52.0) 35((4.4)
7 (7.8) 1 (0.8) 5 (0.9) 7 (7.8) 8 (6.5) 20 (3.4) 106 (30.5) 13 (9.8) 13 (5.1) 163 (47.0) 37 (28.0) 45 (17.6) 368 (87.6) 209 (82.6) 547 (65.8)
347 (79.4) 132 (51.8) 256 (30.5)
90 (20.6) 123 (48.2) 582 (69.5)
ROSC no. (%) No. (%) Survival no. (%) ROSCc no. (%) No. (%)
Patients shocked Male no. (%)b
277
c
67.7 70 1530
Information on age was available in 1398 subjects. Gender was recorded for 1504 subjects. ROSC defined as return of spontaneous circulation on leaving scene. b
a
Whole group
437 (28.6) 62.9 63 255 (16.7) 63.7 65.5 838 (54.8) 71.4 74 A. On-site AED B. First responder outside home C. First responder at home
No. (%)
Age mean mediana
Age
Responder
Table 1
Demographics and outcome in three groups of patients defined according to responder and location
Patients not shocked
Survival no. (%)
A national scheme for public Access defibrillation in England and Wales
Age (estimated in some cases) was recorded as completed years in 1398 subjects; 1028 were recorded as men, 353 as women. Arrests occurred at a significantly younger age in males (mean 66.2 year, median 68) than females (mean 72.2, median 75, P < 0.001). The mean ages of groups A (62.9) and B (63.7) were similar, but patients attended by CFRs at home were significantly older, mean age 71.4 years (P < 0.001). Table 2 shows that overall survival in this series displayed an inverted U-shaped relationship to age, with highest survival rates at ages 45—74 and poorer outcome in both younger and older patients. Although mean ages were similar in groups A and B, the proportion aged 45—74 was greater in group A (77.3%) than in group B (65.0%) as well as group C (45.8%).
Overall outcomes Considering the groups as a whole, regardless of whether shocks were given, (Table 1) more patients attended by on-site personnel achieved ROSC (P < 0.001) or survived (P < 0.001) than when attended by CFRs with mobile AEDs outside the home. In turn, the patients attended by
278 Table 2
M.C. Colquhoun et al. Proportion of victims who survived, by age
Age
Proportion surviving
Under 25 25—34 35—44 45—54 55—64 65—74 75—84 85 and over
1/12 (8.3%) 0/24 (0%) 4/47 (8.5%) 15/144 (10.4%) 45/283 (15.9%) 45/382 (11.8%) 17/372 (4.6%) 3/134 (2.2%)
Total
130/1398 (9.3%)
Table 4 Influence of bystander CPR before AED arrival on outcome Outcome criterion
CPR (%)
No CPR (%)
Shock administered Overall ROSC Overall survival ROSC in those shocked Survival in those shocked
64.0 25.2 15.4 36.9 22.4
36.0 13.2 5.0 28.6 12.1
Table 5
Effect of delays to start CPR and place AED pads
Comparison
CFRs at these locations fared significantly better than patients attended at home for ROSC (P < 0.001) and survival (P = .006).
Presence of shockable rhythms Significantly more patients were administered shocks by on-site responders than by CFRs acting outside the home (P < 0.001), who in turn more often administered shocks to patients attended at these locations than in those attended at home (P < 0.001). Considering only those patients who were shocked, those attended by on-site personnel did significantly better than those attended by CFRs outside the home (P < 0.001 for both ROSC and survival). Those attended by CFRs outside home also fared better than those attended at home, though differences are of borderline statistical significance (P = .017 for ROSC, P = .075 for survival).
(P < 0.001) (P < 0.001) (P < 0.001) (P = .02) (P < 0.001)
CPR delay (min)
Pad placement delay (min)
Mean Median Mean Median Group A 2.9 Group B 6.7 Group C 11.1 Shock given 4.7 No shock 11.8 ROSC 3.2 No ROSC 9.3 Survival to discharge 2.2 Death 8.6 ROSC in those shocked 2.9 No ROSC in those shocked 5.6 Survival in those shocked 2.2 Death in those shocked 5.2
2.0 5.0 7.0 3.5 7.0 2.0 6.0 1.8 5.0 2.0 5.0 1.5 4.0
5.0 9.4 12.3 7.0 13.2 5.0 11.3 3.8 10.7 4.8 8.1 3.8 7.7
4.0 8.0 9.0 6.0 9.0 4.0 8.0 3.0 8.0 4.0 7.0 3.0 6.0
Delays to start of CPR and placement of AED pads Witnessed arrests The proportion of unwitnessed arrests was highest in group C (39.4%), lowest in group A (8.9%) and intermediate in group B (24.7%). Analysis showed a highly significant disadvantage for unwitnessed arrests compared with witnessed arrests (Table 3).
Cardiopulmonary resuscitation
Discussion
The proportion of victims in whom CPR was started before the arrival of the AED was 70.9% in group A, 48.6% in group B, falling to 26.5% in group C. Analysis showed a significant advantage when CPR was applied (Table 4).
Table 3 arrests
The delay to start CPR and the interval from collapse to AED pad placement were recorded in 954 and 1017 patients, respectively. The durations of both types of delay increased steadily from group A through group B to group C (Table 5, P < 0.001). Highly significant disadvantages were associated with longer delays of both kinds, with P < 0.001 for each comparison in Table 5.
Outcomes in witnessed compared to unwitnessed
Outcome criterion
Witnessed arrest (%)
Unwitnessed (%)
Shock administered Overall ROSC Overall survival ROSC in those shocked Survival in those shocked
57.6 22.7 12.3 35.4 19.6
23.8 7.2 2.3 20.4 7.8
(P < 0.001) (P < 0.001) (P < 0.001) (P = 0.003) (P = 0.004)
This is the first report of a national scheme that has incorporated PAD into mainstream health care provision. The project was an ambitious move by the authorities because at the time it was announced very little published evidence existed for its potential effectiveness. A National Health Service that includes a statutory ambulance service and the other bodies with national coverage including the Resuscitation Council (UK), the BHF, the British Red Cross and St John Ambulance provided an infrastructure that facilitated such a scheme. The role of the DH was crucial in the coordination of all these organizations from the outset. The contribution of the participating organizations depended largely on volunteers both for training and for using the AEDs. Employers agreed to release staff, often at significant cost, with little expectation of tangible benefit. Their tolerance was well rewarded by the credit and
A national scheme for public Access defibrillation in England and Wales attendant publicity they received when lives were saved. A further important factor was the absence of legal impediment under UK law for lay persons to use an AED. There is no ‘Good Samaritan’ legislation in the UK, yet the present legal climate also makes it very unlikely that an operator or their responsible organization could be sued for consequences arising from responding to an emergency in a PAD scheme.19 The results were very much better when the AED was immediately available as part of the on-site strategy than when it had to be transported to a patient. As expected, survival was positively associated with witnessed arrest, CPR by bystanders, and the presence of a shockable rhythm, all of which were more common in this group. The times between collapse and the start of CPR and attempted defibrillation were also short—–much quicker than is usually possible for ambulance services in the UK that currently report around 5% ROSC at hospital door and 2.5% survival.20 The on-site strategy has now proved to be very effective at places where there is an appreciable risk of cardiac arrest occurring. The level of such risk that makes implementation mandatory remains to be defined. The key principles of PAD — lay responders can initiate CPR and attempt defibrillation sooner than conventional ambulance services — apply to the approach using community first responders described reported here. As expected, their results were appreciably less good than those obtained with the on-site strategy, and were particularly poor in the patients who arrested at home. The favorable prognostic factors were less prevalent in both groups of patients they attended. They attended more unwitnessed arrests, CPR was administered less frequently and when attempted was started later, the AED pads were attached later and fewer patients were shocked, especially in those arresting at home. Many of the home arrests were unwitnessed making it likely that any prospect of successful resuscitation had passed in many cases. These patients were also older, with the likelihood of co-morbidity, or inter-current illness. The results achieved by community first responders should be regarded as a promising start to a strategy at an early stage of development; their results are already as good as those achieved by the ambulance service. They provide an additional approach to the treatment of the victims of sudden cardiac death who would otherwise have no chance of successful resuscitation. They have the potential to reach patients at sites where AEDs cannot generally be located, including private homes. There are other important considerations when comparing the two approaches. For the on-site strategy to be effective, there must be a considerable density of units in the vulnerable area. Inevitably the chance of any one AED being used is small but if it is used then the chance of success is high. In the ‘mobile’ strategy the number of units required is relatively small, they tend to be used more frequently, but with appreciably less success. The relative cost effectiveness of the two approaches has not been defined; the costs in terms per life saved may be similar. The two approaches are complementary and each is essential to provide a comprehensive response in the community to the problem of sudden cardiac death. While the effectiveness of the onsite strategy is now established, first responder use is at an
279
early stage of development. Both strategies show promise that deserves to be developed further.
Limitations of study This study is dependent on the voluntary reporting of resuscitation attempts by those concerned. For ‘on-site’ use the Department of Health data were collected systematically by their employees and are thought to be complete. The BHF requires all those who receive an AED from them to report every use of the device, but compliance is uncertain. The voluntary societies (which operated many AEDs in this study) require their use to be systematically reported by their members. For CFRs, reports are received from ambulance services that routinely collect data on cardiac arrests they attend. For both strategies, some resuscitation attempts may not have been reported, but the systems in place make it likely that the great majority of events are included. Whilst this factor may have exaggerated the benefits of PAD, another factor may operate in the other direction. Confidentiality regulations in the UK make it very difficult to follow patients’ progress once they have been admitted to hospital. We have attempted to follow up any patient who left the scene with the circulation restored; most survivors are happy to be identified once they learn of our interest, and many wish to thank their rescuers. It is possible however, that not all survivors were identified as such. Some of the intervals were estimates and therefore lack precision. The errors are not likely to be great because the durations were relatively brief. The problem is common to all reports of this type and therefore does not invalidate comparisons.
Conflict of interest statement The database is funded by the Resuscitation Council (UK). Professor Chamberlain is supported (expenses only) by a grant from the Laerdal foundation. The remaining authors have no conflicts of interest to declare.
Acknowledgements We thank Jane Turner, Anna Oakley, Kim Read and Helen Williams for administrative and secretarial support.
References 1. Jaggarao NSV, Sless H, Grainger R, Vincent R, Chamberlain DA. Defibrillation at a football stadium: an experiment with Brighton and Hove Albion. BMJ 1982;284:1451—3. 2. Wassertheil J, Keane G, Fisher N, Leditschke JF. Cardiac arrest outcomes at the Melbourne Cricket Ground and Shrine of Remembrance using a tiered response strategy—–a forerunner to Public Access Defibrillation. Resuscitation 2000;44:97— 104. 3. O’Rourke M, Donaldson E. Management of ventricular fibrillation in commercial airliners. Lancet 1995;345:515—6. 4. Valenzuela TD, Roe DJ, Nichol G, Clark LL, Spaite DW, Hardman RG. Outcomes after rapid defibrillation by security officers after cardiac arrest in casinos. N Engl J Med 2000;343:1206—9.
280 5. Page RL, Joglar JA, Kowal RC, et al. Use of automated defibrillators by a U.S. airline. N Engl J Med 2000;343:1210—6. 6. Capucci A, Aschieri D, Piepoli MF, Bardy GH, Iconomu E, Arvedi M. Tripling survival from sudden cardiac arrest via early defibrillation without traditional education in cardiopulmonary resuscitation. Circulation 2002;106:1065—70. 7. Caffrey SL, Willoughby PJ, Pepe PE, Becker LB. Public use of automated defibrillators. N Engl J Med 2002;347:1242—7. 8. PAD Trial investigators. Public access defibrillation and survival after out-of-hospital cardiac arrest. N Engl J Med 2004;351:637—46. 9. Cappato R, Curnis A, Marzollo P, et al. Prospective assessment of integrating the existing emergency medical system with automated external defibrillators fully operated by volunteers and laypersons for out-of-hospital cardiac arrest: the Brescia Early Defibrillation Study (BEDS). Eur Heart J 2006;27: 553—61. 10. Davies CS, Colquhoun MC, Boyle R, Chamberlain DA. A National Programme for on-site defibrillation by lay persons in selected high risk areas: initial results. Heart 2005;91:1299—302. 11. Priori SG, Bossaert LL, Chamberlain DA, et al. ESC-ERC recommendations for the use of automated external defibrillators (AEDs) in Europe. Eut Heart J 2004;25:437—45. 12. Litwin PE, Eisenberg MS, Hallstrom AP, Cummins RO. The location of collapse and its effect on survival from cardiac arrest. Ann Emerg Med 1987;16:787—91. 13. DeVreede-Swagemakers JJM, Gorgels APM, Dubois-Arbouw, et al. et al. Out-of-hospital cardiac arrest in the 1990s.: a population based study in the Maastricht area on incidence, characteristics and survival. J Am Coll Cardiol 1997;30:1500—5.
M.C. Colquhoun et al. 14. Holmberg M, Holmberg S, Herlitz J, et al. For the Swedish cardiac arrest registry. Survival after cardiac arrest outside hospital in Sweden. Resuscitation 1998;36:29—36. 15. Department of Health. Saving lives: our healthier nation. London HMSO 1999. 16. Davies CS, Colquhoun MC, Graham S, Evans TR, Chamberlain DA. Public access defibrillation: the establishment of a national scheme for England. Resuscitation 2002;52:13—21. 17. Colquhoun MC, Davies CS, Harris S, Harris R, Chamberlain DA. Public access defibrillation—–designing a universal report form and database for a national programme. Resuscitation 2004;61:49—54. 18. Cardiac arrest and cardiopulmonary resuscitation outcome reports: update and simplification of the Utstein templates for resuscitation registries. A statement for healthcare professionals from a task force of the international liaison committee on resuscitation (American Heart Association, European Resuscitation Council, Australian Resuscitation Council, New Zealand Resuscitation Council, Heart and Stroke Foundation of Canada, InterAmerican Heart Foundation, Resuscitation Council of Southern Africa) Resuscitation 2004; 63:233—249. 19. Colquhoun MC and Martineau E. The legal status of those who attempt resuscitation. Resuscitation Council, London 2000 http://www.resus.org.uk/pages/legal.htm. 20. Evans L. ASA/JRCALC National Out-of-Hospital Cardiac Arrest Project 2004. Prepared on behalf of the ASA and Joint Royal College Ambulance Liaison Committee (JRCALC) Clinical Effectiveness Committee http://www.asa.uk.net/content files/files/ NationalOutOfHospitalCardiacArrestAudit2004.pdf Accessed 23 October 2007.
available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/resuscitation
CLINICAL PAPER
A national scheme for public access defibrillation in England and Wales: Early results夽 M.C. Colquhoun a,b,c,∗, D.A. Chamberlain a,b, R.G. Newcombe a, R. Harris c, S. Harris c, K. Peel d, C.S. Davies e, R. Boyle e a
Department of Primary Care and Public Health, (Medical Statistics), School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, United Kingdom b Prehospital Emergency Research Unit, School of Medicine, Cardiff University, Lansdowne Hospital, Sanitorium Road, Cardiff CF11 8PL, United Kingdom c The Resuscitation Council (UK), 5th Floor, Tavistock House North, Tavistock Square, London WC1H 9HR, United Kingdom d The British Heart Foundation, 14 Fitzhardinge Street, London W1H 6DH, United Kingdom e Department of Health, Wellington House (Level 4), 133-155 Waterloo Road, London SE1 8UG, United Kingdom Received 10 February 2008; received in revised form 15 March 2008; accepted 24 March 2008
KEYWORDS Defibrillation; Public access defibrillation; Automated external defibrillator
Summary Background: Automated external defibrillators (AEDs) operated by lay persons are used in the UK in a National Defibrillator Programme promoting public access defibrillation (PAD). Methods: Two strategies are used:(1) Static AEDs installed permanently in busy public places operated by those working nearby. (2) Mobile AEDs operated by community first responders (CFRs) who travel to the casualty. Results: One thousand five hundred and thirty resuscitation attempts. With static AEDs, return of spontaneous circulation (ROSC) was achieved in 170/437 (39%) patients, hospital discharge in 113/437 (26%). With mobile AEDs, ROSC was achieved in 110/1093 (10%), hospital discharge in 32 (2.9%) (P < 0.001 for both variables).More shocks were administered with static AEDS 347/437 (79%) than mobile AEDs 388/1093 (35.5%) P < 0.001. Highly significant advantages existed for witnessed arrests, administration of shocks, bystander CPR before arrival of AED and short delays to start CPR and attach AED. These factors were more common with static AEDs. For CFRs, patients at home did less well than those at other locations for ROSC (P < 0.001) and survival (P = .006). Patients at home were older, more arrests were unwitnessed, fewer shocks were given, delays to start CPR and attach electrodes were longer.
夽 A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2008.03.226. ∗ Corresponding author at: Department of Primary Care and Public Health, (Medical Statistics), School of Medicine, Cardiff University, Heath Park, Cardiff CF14 4XN, United Kingdom. Tel.: +44 29 2093 2903. E-mail address: [email protected] (M.C. Colquhoun).
0300-9572/$ — see front matter © 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2008.03.226
276
M.C. Colquhoun et al. Conclusions: PAD is a highly effective strategy for patients with sudden cardiac arrest due to ventricular fibrillation who arrest in public places where AEDs are installed. Community responders who travel with an AED are less effective, but offer some prospect of resuscitation for many patients who would otherwise receive no treatment. Both strategies merit continuing development. © 2008 Elsevier Ireland Ltd. All rights reserved.
Introduction The use of automated external defibrillators (AEDs) by lay persons who are not professional health care providers, (‘public access defibrillation’, PAD) has proved an effective strategy in the management of sudden cardiac arrest occurring outside hospital.1—10 Delays in performing defibrillation can be appreciably reduced if those nearby can use an AED before the arrival of the emergency medical services. Most reports of PAD have described the use of AEDs made available in public places where the possibility of cardiac arrests can be foreseen and where lay persons working in the vicinity can be trained to use them.1—5,7,10 This is sometimes termed the ‘static AED’ or ‘on-site’ strategy.10,11 The alternative ‘mobile’ strategy for PAD employs lay volunteers as ‘community first responders’ (CFRs) dispatched by ambulance control centres because they can reach a victim sooner than a conventional ambulance. In some areas of the United Kingdom (UK) members of the fire and police services also act in this role. Such community first responders are not limited to specific sites. They may provide the best option for treating patients at home, the commonest place for cardiac arrest to occur.12—14 In England and Wales, PAD developed during the 1990s principally through the provision of AEDs driven by the British Heart Foundation (BHF), the UK’s leading heart charity. This was to equip not only locations where the ‘on-site’ strategy was planned but also community first responders (FRs) for the mobile strategy planned in association with ambulance services. Later, the Government, through the Department of Health (DH), made PAD a core part of the National Health Service (NHS) in England by placing 700 AEDs at high risk locations.15 These complemented AEDs already installed at other public sites or used by community first responder schemes. Subsequently, the BHF was awarded a national lottery grant and joined forces with the Department of Health to coordinate the expansion of both PAD strategies throughout England through a National Defibrillator Programme (NDP). The Welsh Assembly Government and the BHF later established similar arrangements in Wales. This paper describes the largest series of resuscitation attempts reported to date within an evolving PAD programme and is based on nationwide statistics. We report the effectiveness of defibrillation by lay persons and the relative effectiveness of different PAD strategies used in the UK.
Methods The establishment of the National Defibrillator Programme, methods of data collection and standard report form used are described in detail elsewhere.16,17 The cost of
AEDs, related equipment, training and administration was provided by the NHS, the BHF, and a national lottery fund. (a) ‘On-site’ defibrillators The DH placed AEDs in busy public places identified from routine ambulance data as sites where cardiac arrest was liable to occur such as airports and major railway stations. AEDs are kept in unlocked protective cabinets within 200 m walking distance from any part of the premises to which the public has access. Staff working at these sites volunteered to be trained over 4 h to provide basic life support (BLS) and to use an AED. A standardized competency-based curriculum with adequate manikin practice is supplemented by simulated cardiac arrest scenarios. Most training is provided by the statutory ambulance services. Similar arrangements were adopted by other organizations in sports facilities, workplaces, shopping centres and exhibition halls; these AEDs were usually funded by the BHF. At major sporting venues, members of the voluntary societies such as St John Ambulance and the Red Cross attend during events with one or more AEDs. (b) ‘‘Mobile’ defibrillators with community first responders Ambulance services train and equip lay community first responders to provide a service in the areas they administer. Dispatch is by ambulance control centres in response to emergency calls from the public. This strategy is commonly used in rural areas where ambulance response times are necessarily long. Police and fire services coordinate their own training, usually in conjunction with the local ambulance service. Deployment is by ambulance control centres or the control centre for the organization concerned.
Data collection and statistical analysis Data are recorded at the location on a report form compatible with the Utstein system for uniform recording of prehospital resuscitation attempts.18 The intervals between collapse and both the institution of basic life support and attachment of AED pads are usually estimated, but are sometimes supported by data from ambulance or other control systems. The interval from collapse to placement of pads allows a comparison of time to treatment for patients with and without shockable rhythms. Data from report forms were entered into a Microsoft Access database, and subsequently into SPSS v 12.0.2 for statistical analysis. Comparisons were made between groups A and B and between groups B and C as defined below, using chi-square tests for binary variables such as sex or survival, and Mann—Whitney tests for continuous variables
13((1.6)
viz. age and delays to start of CPR and AED pad placement.
Results This report is based on 1530 resuscitation attempts initiated by lay persons equipped with an AED from 11th March 1999 to 31st December 2005. Shocks were administered to 735 (48%) victims, with return of spontaneous circulation (ROSC) in 245 of them (33%). One hundred and thirty-two (18%) of those who received shocks were discharged alive from hospital. Outcome was poor among 795 unshocked patients, with 35 (4.4%) attaining ROSC and 13 (1.6%) surviving. Important differences in patient characteristics and outcome were apparent between patients treated ‘on-site’ (group A) and those treated by community first responders using the mobile strategy; among the latter category there were further important differences between patients treated outside the home (group B) and those treated at home (group C). The principal differences are shown in Table 1.
132((18.0)
Sex One thousand one hundred and twenty-four (74.7%) of 1504 victims whose sex was recorded were male. A higher proportion of males than females were shocked (53.2% vs. 31.1%, P < 0.001), achieved ROSC (20.4% vs. 11.8%, P < 0.001) and survived (10.8% vs. 4.2%, P < 0.001). Among patients who received shocks, however, similar proportions of the two sexes achieved ROSC (M 33.8% vs. F 31.4%, P = .61) with no significant difference in survival (M 18.6% vs. F 12.7%, P = .13).
1124((74.7)
735((48.0) 245((33.3)
795((52.0) 35((4.4)
7 (7.8) 1 (0.8) 5 (0.9) 7 (7.8) 8 (6.5) 20 (3.4) 106 (30.5) 13 (9.8) 13 (5.1) 163 (47.0) 37 (28.0) 45 (17.6) 368 (87.6) 209 (82.6) 547 (65.8)
347 (79.4) 132 (51.8) 256 (30.5)
90 (20.6) 123 (48.2) 582 (69.5)
ROSC no. (%) No. (%) Survival no. (%) ROSCc no. (%) No. (%)
Patients shocked Male no. (%)b
277
c
67.7 70 1530
Information on age was available in 1398 subjects. Gender was recorded for 1504 subjects. ROSC defined as return of spontaneous circulation on leaving scene. b
a
Whole group
437 (28.6) 62.9 63 255 (16.7) 63.7 65.5 838 (54.8) 71.4 74 A. On-site AED B. First responder outside home C. First responder at home
No. (%)
Age mean mediana
Age
Responder
Table 1
Demographics and outcome in three groups of patients defined according to responder and location
Patients not shocked
Survival no. (%)
A national scheme for public Access defibrillation in England and Wales
Age (estimated in some cases) was recorded as completed years in 1398 subjects; 1028 were recorded as men, 353 as women. Arrests occurred at a significantly younger age in males (mean 66.2 year, median 68) than females (mean 72.2, median 75, P < 0.001). The mean ages of groups A (62.9) and B (63.7) were similar, but patients attended by CFRs at home were significantly older, mean age 71.4 years (P < 0.001). Table 2 shows that overall survival in this series displayed an inverted U-shaped relationship to age, with highest survival rates at ages 45—74 and poorer outcome in both younger and older patients. Although mean ages were similar in groups A and B, the proportion aged 45—74 was greater in group A (77.3%) than in group B (65.0%) as well as group C (45.8%).
Overall outcomes Considering the groups as a whole, regardless of whether shocks were given, (Table 1) more patients attended by on-site personnel achieved ROSC (P < 0.001) or survived (P < 0.001) than when attended by CFRs with mobile AEDs outside the home. In turn, the patients attended by
278 Table 2
M.C. Colquhoun et al. Proportion of victims who survived, by age
Age
Proportion surviving
Under 25 25—34 35—44 45—54 55—64 65—74 75—84 85 and over
1/12 (8.3%) 0/24 (0%) 4/47 (8.5%) 15/144 (10.4%) 45/283 (15.9%) 45/382 (11.8%) 17/372 (4.6%) 3/134 (2.2%)
Total
130/1398 (9.3%)
Table 4 Influence of bystander CPR before AED arrival on outcome Outcome criterion
CPR (%)
No CPR (%)
Shock administered Overall ROSC Overall survival ROSC in those shocked Survival in those shocked
64.0 25.2 15.4 36.9 22.4
36.0 13.2 5.0 28.6 12.1
Table 5
Effect of delays to start CPR and place AED pads
Comparison
CFRs at these locations fared significantly better than patients attended at home for ROSC (P < 0.001) and survival (P = .006).
Presence of shockable rhythms Significantly more patients were administered shocks by on-site responders than by CFRs acting outside the home (P < 0.001), who in turn more often administered shocks to patients attended at these locations than in those attended at home (P < 0.001). Considering only those patients who were shocked, those attended by on-site personnel did significantly better than those attended by CFRs outside the home (P < 0.001 for both ROSC and survival). Those attended by CFRs outside home also fared better than those attended at home, though differences are of borderline statistical significance (P = .017 for ROSC, P = .075 for survival).
(P < 0.001) (P < 0.001) (P < 0.001) (P = .02) (P < 0.001)
CPR delay (min)
Pad placement delay (min)
Mean Median Mean Median Group A 2.9 Group B 6.7 Group C 11.1 Shock given 4.7 No shock 11.8 ROSC 3.2 No ROSC 9.3 Survival to discharge 2.2 Death 8.6 ROSC in those shocked 2.9 No ROSC in those shocked 5.6 Survival in those shocked 2.2 Death in those shocked 5.2
2.0 5.0 7.0 3.5 7.0 2.0 6.0 1.8 5.0 2.0 5.0 1.5 4.0
5.0 9.4 12.3 7.0 13.2 5.0 11.3 3.8 10.7 4.8 8.1 3.8 7.7
4.0 8.0 9.0 6.0 9.0 4.0 8.0 3.0 8.0 4.0 7.0 3.0 6.0
Delays to start of CPR and placement of AED pads Witnessed arrests The proportion of unwitnessed arrests was highest in group C (39.4%), lowest in group A (8.9%) and intermediate in group B (24.7%). Analysis showed a highly significant disadvantage for unwitnessed arrests compared with witnessed arrests (Table 3).
Cardiopulmonary resuscitation
Discussion
The proportion of victims in whom CPR was started before the arrival of the AED was 70.9% in group A, 48.6% in group B, falling to 26.5% in group C. Analysis showed a significant advantage when CPR was applied (Table 4).
Table 3 arrests
The delay to start CPR and the interval from collapse to AED pad placement were recorded in 954 and 1017 patients, respectively. The durations of both types of delay increased steadily from group A through group B to group C (Table 5, P < 0.001). Highly significant disadvantages were associated with longer delays of both kinds, with P < 0.001 for each comparison in Table 5.
Outcomes in witnessed compared to unwitnessed
Outcome criterion
Witnessed arrest (%)
Unwitnessed (%)
Shock administered Overall ROSC Overall survival ROSC in those shocked Survival in those shocked
57.6 22.7 12.3 35.4 19.6
23.8 7.2 2.3 20.4 7.8
(P < 0.001) (P < 0.001) (P < 0.001) (P = 0.003) (P = 0.004)
This is the first report of a national scheme that has incorporated PAD into mainstream health care provision. The project was an ambitious move by the authorities because at the time it was announced very little published evidence existed for its potential effectiveness. A National Health Service that includes a statutory ambulance service and the other bodies with national coverage including the Resuscitation Council (UK), the BHF, the British Red Cross and St John Ambulance provided an infrastructure that facilitated such a scheme. The role of the DH was crucial in the coordination of all these organizations from the outset. The contribution of the participating organizations depended largely on volunteers both for training and for using the AEDs. Employers agreed to release staff, often at significant cost, with little expectation of tangible benefit. Their tolerance was well rewarded by the credit and
A national scheme for public Access defibrillation in England and Wales attendant publicity they received when lives were saved. A further important factor was the absence of legal impediment under UK law for lay persons to use an AED. There is no ‘Good Samaritan’ legislation in the UK, yet the present legal climate also makes it very unlikely that an operator or their responsible organization could be sued for consequences arising from responding to an emergency in a PAD scheme.19 The results were very much better when the AED was immediately available as part of the on-site strategy than when it had to be transported to a patient. As expected, survival was positively associated with witnessed arrest, CPR by bystanders, and the presence of a shockable rhythm, all of which were more common in this group. The times between collapse and the start of CPR and attempted defibrillation were also short—–much quicker than is usually possible for ambulance services in the UK that currently report around 5% ROSC at hospital door and 2.5% survival.20 The on-site strategy has now proved to be very effective at places where there is an appreciable risk of cardiac arrest occurring. The level of such risk that makes implementation mandatory remains to be defined. The key principles of PAD — lay responders can initiate CPR and attempt defibrillation sooner than conventional ambulance services — apply to the approach using community first responders described reported here. As expected, their results were appreciably less good than those obtained with the on-site strategy, and were particularly poor in the patients who arrested at home. The favorable prognostic factors were less prevalent in both groups of patients they attended. They attended more unwitnessed arrests, CPR was administered less frequently and when attempted was started later, the AED pads were attached later and fewer patients were shocked, especially in those arresting at home. Many of the home arrests were unwitnessed making it likely that any prospect of successful resuscitation had passed in many cases. These patients were also older, with the likelihood of co-morbidity, or inter-current illness. The results achieved by community first responders should be regarded as a promising start to a strategy at an early stage of development; their results are already as good as those achieved by the ambulance service. They provide an additional approach to the treatment of the victims of sudden cardiac death who would otherwise have no chance of successful resuscitation. They have the potential to reach patients at sites where AEDs cannot generally be located, including private homes. There are other important considerations when comparing the two approaches. For the on-site strategy to be effective, there must be a considerable density of units in the vulnerable area. Inevitably the chance of any one AED being used is small but if it is used then the chance of success is high. In the ‘mobile’ strategy the number of units required is relatively small, they tend to be used more frequently, but with appreciably less success. The relative cost effectiveness of the two approaches has not been defined; the costs in terms per life saved may be similar. The two approaches are complementary and each is essential to provide a comprehensive response in the community to the problem of sudden cardiac death. While the effectiveness of the onsite strategy is now established, first responder use is at an
279
early stage of development. Both strategies show promise that deserves to be developed further.
Limitations of study This study is dependent on the voluntary reporting of resuscitation attempts by those concerned. For ‘on-site’ use the Department of Health data were collected systematically by their employees and are thought to be complete. The BHF requires all those who receive an AED from them to report every use of the device, but compliance is uncertain. The voluntary societies (which operated many AEDs in this study) require their use to be systematically reported by their members. For CFRs, reports are received from ambulance services that routinely collect data on cardiac arrests they attend. For both strategies, some resuscitation attempts may not have been reported, but the systems in place make it likely that the great majority of events are included. Whilst this factor may have exaggerated the benefits of PAD, another factor may operate in the other direction. Confidentiality regulations in the UK make it very difficult to follow patients’ progress once they have been admitted to hospital. We have attempted to follow up any patient who left the scene with the circulation restored; most survivors are happy to be identified once they learn of our interest, and many wish to thank their rescuers. It is possible however, that not all survivors were identified as such. Some of the intervals were estimates and therefore lack precision. The errors are not likely to be great because the durations were relatively brief. The problem is common to all reports of this type and therefore does not invalidate comparisons.
Conflict of interest statement The database is funded by the Resuscitation Council (UK). Professor Chamberlain is supported (expenses only) by a grant from the Laerdal foundation. The remaining authors have no conflicts of interest to declare.
Acknowledgements We thank Jane Turner, Anna Oakley, Kim Read and Helen Williams for administrative and secretarial support.
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