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Practice variability among the EMS systems participating in Cardiac Arrest Registry to Enhance Survival (CARES)
Resuscitation 83 (2012) 76–80
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Clinical paper
Practice variability among the EMS systems participating in Cardiac Arrest Registry to Enhance Survival (CARES)夽,夽夽 Prasanthi Govindarajan a,∗ , Lisa Lin b , Adam Landman c , Jason T. McMullan d , Bryan F. McNally e , Allison J. Crouch f , Comilla Sasson g a
Department of Emergency Medicine, University of California San Francisco, 505 Parnassus Avenue, L 126, Mail Code 0208, San Francisco, CA 94143-0208, United States University of California San Francisco School of Medicine, San Francisco, CA 94143, United States c Department of Emergency Medicine Brigham and Women’s Hospital, 75 Francis St., Boston, MA 02115, United States d Department of Emergency Medicine, University of Cincinnati, 231 Albert Sabin Way, PO Box 670769, Cincinnati, OH 45267-0769, United States e Department of Emergency Medicine, Emory University, 49 Jesse Hill, Jr. Drive, Atlanta, GA 30303, United States f Cardiac Arrest Registry to Enhance Survival, Atlanta, GA, United States g Department of Emergency Medicine, University of Colorado, Mail Code #0108, 777 Bannock St, Denver, CO 80206, United States b
a r t i c l e
i n f o
Article history: Received 10 January 2011 Received in revised form 14 June 2011 Accepted 21 June 2011
Keywords: Emergency Medical Services Resuscitation
a b s t r a c t Study objective: To describe the demographic, organizational and provider characteristics of the Emergency Medical Services (EMS) agencies participating in the Cardiac Arrest Registry to Enhance Survival (CARES). Methods: A web based survey instrument was developed by the CARES investigators and distributed to the EMS agencies participating in CARES in 2008. Survey questions addressed three domains related to prehospital care: (1) descriptors of the participating EMS agencies, (2) methods of clinical care and clinical protocols used by EMS agencies to deliver out-of-hospital cardiac arrest care and (3) use of resuscitation techniques by EMS agencies. Survey responses were collated and analyzed using descriptive statistics. Results: Surveys were received from 21/25 (84%) sites. The EMS agency characteristics including the response areas served by the agencies, organizational structure, medical direction status and deployment status are described. All respondents were non-volunteer agencies with a large number of them being fire-based (43%). Significant variability among the communities was observed with respect to their medical direction status and deployment status. We also observed differences in the management of OHCA among the participating agencies which included implementation of ACLS guideline updates, presence of termination of resuscitation protocol and destination policies for OHCA subjects. Similar variations between agencies were also observed in the use of resuscitation techniques. Conclusions: Differences were observed between the EMS agencies participating in CARES. The clinical impact of these observed differences in agency and provider characteristics on OHCA outcomes deserves study. © 2011 Elsevier Ireland Ltd. All rights reserved.
1. Background Cardiovascular disease is a leading cause of death in the United States.1 While prevention and treatment regimens have reduced morbidity and mortality resulting from cardiovascular disease, the incidence and survival outcomes of Out-of-Hospital Cardiac Arrest (OHCA) have not improved during the same period.2
夽 A Spanish translated version of the abstract of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2011.06.026. 夽夽 Poster presentation at the National Association of Emergency Medical Services Physicians Annual Meeting, Phoenix, AZ, January 2010 and 13th Annual SAEM Western Regional Research Forum, Sonoma, CA, March 2010. ∗ Corresponding author. Tel.: +1 415 353 8213; fax: +1 415 353 1799. E-mail address: [email protected] (P. Govindarajan). 0300-9572/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2011.06.026
In addition, significant regional and temporal variability in survival has been reported for OHCA some of which have been attributed to differences in case definitions, disparities in care among communities and secondary prevention of conditions leading to OHCA.3,4 However, even after controlling for these factors, unexplained differences in cardiac arrest survival persist, highlighting the need for further research into the reasons for this geographic variability.2 Rates of by-stander cardiopulmonary resuscitation (CPR), socio-economic status, community defibrillation programs and emergency medical services (EMS) agency factors (e.g. experience of providers and differences in treatment protocols) are factors hypothesized to be associated with this variability.5–7 Of the aforementioned factors, prehospital systems would benefit from studies that focus on identifying EMS agency and provider factors in the out of hospital setting that could have an impact on survival to discharge. It is important to understand these factors
P. Govindarajan et al. / Resuscitation 83 (2012) 76–80
and their distribution across EMS agencies since these are potentially modifiable and an important part of OHCA care. Therefore, in this study we describe the demographic differences and practice variations among EMS agencies in the CARES network. 2. Methods 2.1. Study design and population This is a descriptive study of the EMS agencies participating in the Cardiac Arrest Registry to Enhance Survival (CARES) registry using a web based survey (Survey Monkey). All CARES participating agencies in 2008 were invited to participate. 2.2. Cardiac Arrest Registry to Enhance Survival (CARES) CARES is a central repository of OHCA data from EMS agencies throughout the United States and is a collaborative effort between Centers for Disease Control and Prevention (CDC), Emory University, the Southeastern Affiliate of the American Heart Association, and Sansio Corporation (Duluth, MN). The registry serves as a quality improvement project and allows EMS agencies to compare key performance indicators to improve out-of-hospital cardiac arrest care. EMS agencies participating in the registry provide data elements related to OHCA from their 911 dispatch centres, EMS providers, and receiving hospitals. A description of the CARES methodology has been previously published.8,9 2.3. Study survey A structured questionnaire was developed by authors (CS, JM), who are experts in cardiac arrest care and emergency medical services delivery. Face validity was assessed by the study team and the survey was pilot tested by a subset of CARES site coordinators. The survey instrument was distributed by the research coordinator (AC) to the CARES co-ordinators who were emergency medical technicians/paramedics or nurse providers in charge of quality assurance for their agency. The eligible study population included EMS agencies contributing data to CARES as of April 2008. Survey questions addressed three domains related to out-of-hospital care: (1) descriptors of the participating EMS agencies, (2) methods of clinical care and clinical protocols used by EMS agencies to deliver out-of-hospital cardiac arrest care, (3) use of resuscitation techniques by EMS agencies serving CARES sites. (Appendix 1 presents a complete version of the survey questionnaire.) Follow up email and telephone calls were made to improve rates of survey completion and to answer any questions related to incomplete or missing responses. Survey responses were completed by the site administrative staff associated with the CARES project and reviewed by the authors (PG, LL) and CARES project coordinator (AC). All survey responses were collected, stripped of EMS agency identifiers, and entered into a Microsoft Excel 2007 database (PG, LL) (Microsoft Corporation, Redmond, WA). Data was analyzed in aggregate. Results are presented as mean with standard deviation, and medians and interquartile ranges when averages could not be calculated. Analysis was descriptive with no additional inferential statistics. 3. Results Twenty five agencies were members of the network at the time of this survey. Of those, twenty one sites (84%) responded to the survey; one agency did not complete the resuscitation techniques
77
Table 1 Characteristics of the EMS agency participating in CARES. n (IQR) Median number of 911 calls received by the communities Median number of emergency medical dispatches within the communities Median transport volume Median number of hours of ambulance coverage among EMS agencies
64,845 (20250,82604) 64,972 (24329,76032) 43,769 (11718,53277) 366 (204,559) n/N (%)
Response areas served by the EMS agencies Urban only Suburban only Urban and suburban Urban and rural Urban, suburban and rural Organizational type of EMS agencies Community non-profit agency Fire based agency Governmental third service (non-fire) based agency Hospital agency Private non-hospital based agency Medical direction statusa Salaried Contract Volunteer Full-time Part-time Review by committee More than one type of medical direction status Deployment status Fixed Dynamic a
3/21 (14%) 4/21 (19%) 5/21 (24%) 1/21 (5%) 8/21 (38%) 1/21 (5%) 9/21 (43%) 6/21 (29%) 2/21 (10%) 3/21 (14%) 11/21 (52%) 10/21 (48%) 1/21 (5%) 6/21 (29%) 6/21 (29%) 1/21 (5%) 12/21 (57%) 12/21 (57%) 12/21 (43%)
Total exceeds 100% due to overlap between categories.
section of the survey. The details of the participating sites can be found at https://mycares.net.9 3.1. Study survey questionnaire 3.1.1. Description of the CARES communities The descriptors of the CARES survey respondents are described in Table 1; 20/21 (95%) agencies serve sites with a population of more than 50,000 people (range 58,000–2.1 million) and 14/21 (67%) of the survey respondents report a population density of >1000 persons/square mile based on the 2000 U.S. Census population estimate. While all sites meet the criteria of the urbanized areas/urban clusters based on the official U.S. Census Bureau definitions, 9/21 (43%) survey respondents reported serving a combination of rural and urban areas and 5/21 (24%) reported serving a combination of urban and suburban areas.10 3.2. Characteristics of EMS agencies Emergency medical dispatch and the transport volumes for the agencies varied widely (Table 1). Five types of EMS service models serve the CARES sites. Nine (43%) sites are served by fire department-based EMS service providers and six sites (29%) are supported by non-fire-based EMS agencies. All respondents are non-volunteer organizations. Approximately one-third (6/21) of the EMS agencies within CARES have full-time medical directors and another third of the EMS agencies had part-time medical directors (6/21). More than half (57%) of the agencies have various sources of medical direction (i.e. single director, review committee, management committee). About 50% (n = 12/21) of the agencies use a fixed deployment model to deliver emergency services, where resources respond from a pre-designated and fixed location (e.g. fire station). Another 43% use dynamic deployment strategies, where the locations of specific ambulances are con-
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P. Govindarajan et al. / Resuscitation 83 (2012) 76–80
Fig. 1. Practice variation in out of hospital management of cardiac arrest among surveyed EMS agencies.
stantly redistributed according to overall system demand and resource availability. Although EMS agencies were of different organizational types, advanced life support response assignment configuration was similar. 3.3. Characteristics of EMS providers as reported by CARES agencies The survey respondents reported a total of 198 first responder units and 4556 paramedics during the study period. Of the total number of first responder units, number of first responder basic life support trained units (n = 112) was higher than automated external defibrillation first responder units (n = 45) or advanced life support units (n = 72). While the total numbers of paramedics varied widely among the agencies (range 25–664/EMS agency), no relationship was observed between the number of paramedics and total population served. The fire-based agencies have a slightly higher median number of paramedics [n = 230 (IQR 189, 325)] compared with non-fire based agencies [n = 200 (IQR 80, 219)], hospital-based [n = 93 (IQR 61, 122)], and non-hospital-based agencies [n = 206 (IQR 103, 181)]. Twelve agencies (57%) within CARES reported that majority of their EMS providers have at least five years of experience. More than half the number of agencies (57%) reported having at least 75% of their paramedics working full time. 3.3.1. Cardiac arrest management by EMS agencies Our results show wide variations in the protocols utilized for the care of cardiac arrest patients (Fig. 1). Protocol differences among dispatch centres were reported by EMS agencies including the ability to direct 911 callers to an automated external defibrillator (10/21 are able to do so). Ninety percent of the emergency medical dispatch centres among survey respondents reported providing pre-arrival CPR instructions; 95% of the EMS agencies reported
incorporating a quality review program that reviews emergency medical dispatcher instructions. EMS agencies have heterogeneous protocols for OHCA management, including implementation of 2005 ACLS guideline updates, cardiopulmonary resuscitation (CPR) procedures, and prehospital destination criteria for OHCA. About half (52%) of the agencies had modified the 2005 ACLS guidelines largely involving medication administration, airway and ventilatory strategies. Fourteen (67%) agencies reported continuing CPR for 2 min even with preceding bystander CPR. Only six of the surveyed respondents (29%) performed CPR before rhythm check in EMS-witnessed cardiac arrest, while four (19%) reported performing CPR during automated external defibrillator rhythm analysis. Seventeen of 21 (81%) respondents currently have a termination of resuscitation (TOR) protocol. Eighteen of the 21 (86%) agencies performed post-return of spontaneous circulation EKGs and nine reported (43%) triaging these patients to specific destination (resuscitation) hospitals. From a quality improvement (QI) perspective, less than half (43%) of the agencies provided feedback to their supporting first-responder agencies. Approximately a third (27%) supplied summary reports to participating hospitals. Feedback to individual providers was more commonly reported, but was not universal (57%).
3.3.2. Resuscitation techniques use among CARES agencies Similar to the variation noted in field management of OHCA, the use of resuscitation techniques varied widely among EMS agencies. We surveyed the EMS agencies on use of six resuscitation techniques: alternate airways, intraosseous lines, external compression devices, impedence threshold devices, field hypothermia implementation, and real-time CPR feedback devices. Overall, every agency used at least one of these techniques, while no agency used all six techniques. Table 2 provides a summary of resuscitation techniques use by CARES agencies. Alternate
P. Govindarajan et al. / Resuscitation 83 (2012) 76–80 Table 2 Resuscitation techniques among EMS agencies participating in CARES. Resuscitation techniques Alternate/blind airway insertion devices Intra-osseous Field hypothermia External compression device Impedance threshold device (ResQ Pod)
Currently using Num (%)a 19 (95%) 14 (70%) 10 (50%) 9 (45%) 7 (35%)
Years Median (IQR) 5 (2, 11) 2 (1, 3) 0.75 (0.5, 1) 4 (1.5, 4) 2 (2, 2)
a One EMS agency did not respond to the resuscitation techniques questions, leaving a sample size of 20 communities for this section.
airway devices and intraosseous lines are used in 19/20 (95%) and 14/20 (70%) of agencies, respectively. Real-time CPR feedback devices were only used by 2/20 (10%) agencies. External compression devices and alternate airway devices have been in use the longest, for four and five years, respectively. Field hypothermia implementation was the most recently added resuscitation technique. Resuscitation techniques may not be uniformly used in all OHCA, even when the device is available. All agencies that used real-time CPR feedback devices and impedance threshold devices used them in greater than 50% of OHCA. However, <20% of agencies using alternate airway devices and field hypothermia implementation used them in over 50% of OHCA patients. 4. Discussion The communities served and care delivered by EMS agencies participating in CARES differs in many respects. Important areas of variability include agency organizational structure, field management of OHCA, and use of resuscitation techniques. A similar variation was observed among EMS agencies serving the sites participating in the Resuscitation Outcomes Consortium (ROC) network, a clinical trial network created to focus research in the area of prehospital cardiac arrest and traumatic injury.11,12 However, this is the first study to report inter-agency differences for a specific disease process, i.e. OHCA. Demographic differences noted among the communities include size and population of the community and the density of the population. Differences were also observed among the agencies in the volume of 911 calls, EMS transports and the number of advanced life support providers. Although there were significant variations in the numbers of EMS providers, no clear relationship was observed with the total population or the transport volume. While some of this could be explained by the higher number of personnel serving densely populated areas rather than areas with larger population, future studies should identify the staffing pattern and provider configuration associated with favourable OHCA outcomes. In EMS systems, optimization of rapid first response provided by emergency responders such as police or fire-fighters has shown to improve survival in OHCA.13 In our study among the survey respondents, first responders consisted of providers trained in automated external defibrillation only, basic life support techniques and advanced life support techniques. Although a landmark Canadian study showed that in an already optimized defibrillation system, Advanced Life Support Services did not improve survival in OHCA subjects, this model has not been widely adopted by many of the EMS agencies within our network.14 Therefore, future studies using CARES should assess barriers that limit adoption of evidence based models and help to improve efficiency and effectiveness of OHCA management in the prehospital setting. We also found that dispatch-assisted instructions for CPR and directing callers to the closest AED varied widely among our sites. While published literature has shown that dispatch-assisted
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instructions are known to increase rates of bystander CPR and therefore associated with good outcomes the impact of other medical dispatch factors such as dispatcher experience and capabilities such as directing the caller to automated external defibrillator and presence of quality improvement programs on outcome variability are yet to be studied.15 Other significant findings in our study include the wide variability in adherence to clinical guidelines for management of OHCA among agencies. Many EMS agencies adhere to the most current ACLS guidelines, whereas half of survey respondents modified the guidelines in local protocols. Some of these differences are likely due to the agencies being “early adopters” of resuscitation techniques. Guidelines are updated every five years and may take another year for dissemination. Therefore, agencies may modify protocols based on new knowledge available prior to guideline development. Future studies should study the impact of adherence to guidelines on clinical outcomes. Our study also discovered the differences in the use of resuscitation techniques across the EMS agencies as well within individual community arrests. The 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care supported use of in-hospital hypothermia in unconscious adults with spontaneous circulation after OHCA.16 Although pre-hospital initiation of hypothermia may enhance survival, the magnitude has not been described in published studies.17 Alternative airway devices and intra-osseous lines are supported by published studies and endorsed by the 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.16 These three devices were used by the majority of communities participating in this study suggesting these communities are applying evidence-based medicine and AHA recommendations. However, within each community, alternate airway devices, intra-osseous lines, and field hypothermia were not uniformly applied in individual arrests. While some of this may be related to the evidence supporting use of techniques in only specific causes of arrests, other provider factors such as experience of the providers in the use of devices and training in the use of devices to improve outcome benefits must be explored. We observed that EMS agencies in our study population followed some of the AHA recommendations for resuscitation techniques. However, as resuscitation science evolves and updated AHA guidelines are released, resuscitation techniques uses will likely also change. Therefore, future studies may be able to harness CARES data to evaluate the impact of combinations of resuscitation techniques uses on OHCA outcomes. 4.1. Limitations One of the major limitations is that the survey was administered to EMS agencies participating in the CARES network. Since EMS agencies participating in CARES are a self-selected group, they may be systematically different from non-participants. Therefore, the differences observed in this group may not be similar to the non-CARES communities. However, we believe that this is a good starting point since the agencies serve a geographically diverse assortment of communities across the United States and are comprised of many different system designs. Although we have reported data from dispatch centres, this information was not obtained by an independent survey of the dispatch agencies and may be subject to sampling bias. The agency representatives who responded to the survey are knowledgeable about all aspects of OHCA care, including emergency medical dispatch procedures. Lastly, survey data is primarily self-reported, and subject to missing information, non-availability of data, and variability in interpretation of the survey questions. Although some of this
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improved after follow up calls to the agency contacts by the CARES coordinator, we were still left with some missing data in this study. 5. Conclusion Within an existing quality improvement network for OHCA, we have identified differences in the organizational and provider characteristics of the participating EMS agencies and in the protocols and devices used in managing resuscitations. Future studies will need to be conducted to assess which EMS and provider factors are most closely associated with increased survival, with the hope that this information can lead to “best practices” that can be adopted by all EMS agencies. This better understanding of the interplay between EMS characteristics and patient outcomes will hopefully improve OHCA survival. Conflict of interest statement Dr. Govindarajan is a member of the Stroke Task Force, Western States Affiliates, American Heart Association. None of the authors have any conflict of interest. Study contribution PG, CS, JM, BM and AL conceived the study and CS and JM designed the survey instrument. PG, AC and LL collected the data, PG and LL analyzed the data. PG, JM and AL drafted the manuscript, and all authors contributed substantially to its revision. PG takes responsibility for the paper as a whole. Acknowledgements The authors would like to acknowledge the CTSI-K program faculty mentors and peer reviewers, University of California, San Francisco for their feedback on the manuscript and Amy Markowitz, JD for her editorial assistance with this manuscript. Role of funding source: Dr. Govindarajan is supported by a career development award from the Agency of Healthcare Research and Quality K08 HS 017965-02 and Stroke Division of the American Heart Association, Western States Affiliate Clinical Research Program. The funding source has no role in the study design, in the collection, analysis and interpretation of data; in the writing of the manuscript; and in the decision to submit the manuscript for publication.
Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.resuscitation.2011.06.026. References 1. Roger VL, Go AS, Lloyd-Jones DM, et al. Heart disease and stroke statistics–2011 update: a report from the American Heart Association. Circulation 2011;123: e18–209. 2. Nichol G, Thomas E, Callaway CW, et al. Regional variation in out-of-hospital cardiac arrest incidence and outcome. JAMA 2008;300:1423–31. 3. Berdowski J, Berg RA, Tijssen JG, Koster RW. Global incidences of out-of-hospital cardiac arrest and survival rates: systematic review of 67 prospective studies. Resuscitation 2010;81:1479–87. 4. Brooks SC, Schmicker RH, Rea TD, et al. Out-of-hospital cardiac arrest frequency and survival: evidence for temporal variability. Resuscitation 2010;81: 175–81. 5. Hallstrom AP, Ornato JP, Weisfeldt M, et al. Public-access defibrillation and survival after out-of-hospital cardiac arrest. N Engl J Med 2004;351: 637–46. 6. Soo LH, Gray D, Young T, Skene A, Hampton JR. Influence of ambulance crew’s length of experience on the outcome of out-of-hospital cardiac arrest. Eur Heart J 1999;20:535–40. 7. Eschmann NM, Pirrallo RG, Aufderheide TP, Lerner EB. The association between emergency medical services staffing patterns and out-of-hospital cardiac arrest survival. Prehosp Emerg Care 2010;14:71–7. 8. McNally B, Stokes A, Crouch A, Kellermann AL, CARES Surveillance Group. CARES: Cardiac Arrest Registry to Enhance Survival. Ann Emerg Med 2009;54: 674–83. 9. Cardiac Arrest Registry to Enhance Survival (CARES). https://mycares.net/ [accessed on 03.05.11]. 10. Economic Research Service. http://www.ers.usda.gov/Briefing/Rurality/WhatIs Rural/ [accessed on 03.05.11]. 11. Davis DP, Garberson LA, Andrusiek DL, et al. A descriptive analysis of Emergency Medical Service Systems participating in the Resuscitation Outcomes Consortium (ROC) network. Prehosp Emerg Care 2007;11:369–82. 12. Resuscitation Outcomes Consortium. https://roc.uwctc.org/tiki/tiki-index.php [accessed on 03.05.11]. 13. Stiell IG, Wells GA, DeMaio VJ, et al. Modifiable factors associated with improved cardiac arrest survival in a multicenter basic life support/defibrillation system: OPALS Study Phase I results. Ontario Prehospital Advanced Life Support. Ann Emerg Med 1999;33:44–50. 14. Stiell IG, Wells GA, Field B, et al. Advanced cardiac life support in out-of-hospital cardiac arrest. N Engl J Med 2004;351:647–56. 15. Vaillancourt C, Stiell IG, Wells GA. Understanding and improving low bystander CPR rates: a systematic review of the literature. CJEM 2008;10: 51–65. 16. ECC Committee, Subcommittees Task Forces of the American Heart Association. 2005 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation 2005;112:1–203. 17. Hinchey PR, Myers JB, Lewis R, et al. Improved out-of-hospital cardiac arrest survival after the sequential implementation of 2005 AHA guidelines for compressions, ventilations, and induced hypothermia: the Wake County experience. Ann Emerg Med 2010;56:348–57.
Contents lists available at ScienceDirect
Resuscitation journal homepage: www.elsevier.com/locate/resuscitation
Clinical paper
Practice variability among the EMS systems participating in Cardiac Arrest Registry to Enhance Survival (CARES)夽,夽夽 Prasanthi Govindarajan a,∗ , Lisa Lin b , Adam Landman c , Jason T. McMullan d , Bryan F. McNally e , Allison J. Crouch f , Comilla Sasson g a
Department of Emergency Medicine, University of California San Francisco, 505 Parnassus Avenue, L 126, Mail Code 0208, San Francisco, CA 94143-0208, United States University of California San Francisco School of Medicine, San Francisco, CA 94143, United States c Department of Emergency Medicine Brigham and Women’s Hospital, 75 Francis St., Boston, MA 02115, United States d Department of Emergency Medicine, University of Cincinnati, 231 Albert Sabin Way, PO Box 670769, Cincinnati, OH 45267-0769, United States e Department of Emergency Medicine, Emory University, 49 Jesse Hill, Jr. Drive, Atlanta, GA 30303, United States f Cardiac Arrest Registry to Enhance Survival, Atlanta, GA, United States g Department of Emergency Medicine, University of Colorado, Mail Code #0108, 777 Bannock St, Denver, CO 80206, United States b
a r t i c l e
i n f o
Article history: Received 10 January 2011 Received in revised form 14 June 2011 Accepted 21 June 2011
Keywords: Emergency Medical Services Resuscitation
a b s t r a c t Study objective: To describe the demographic, organizational and provider characteristics of the Emergency Medical Services (EMS) agencies participating in the Cardiac Arrest Registry to Enhance Survival (CARES). Methods: A web based survey instrument was developed by the CARES investigators and distributed to the EMS agencies participating in CARES in 2008. Survey questions addressed three domains related to prehospital care: (1) descriptors of the participating EMS agencies, (2) methods of clinical care and clinical protocols used by EMS agencies to deliver out-of-hospital cardiac arrest care and (3) use of resuscitation techniques by EMS agencies. Survey responses were collated and analyzed using descriptive statistics. Results: Surveys were received from 21/25 (84%) sites. The EMS agency characteristics including the response areas served by the agencies, organizational structure, medical direction status and deployment status are described. All respondents were non-volunteer agencies with a large number of them being fire-based (43%). Significant variability among the communities was observed with respect to their medical direction status and deployment status. We also observed differences in the management of OHCA among the participating agencies which included implementation of ACLS guideline updates, presence of termination of resuscitation protocol and destination policies for OHCA subjects. Similar variations between agencies were also observed in the use of resuscitation techniques. Conclusions: Differences were observed between the EMS agencies participating in CARES. The clinical impact of these observed differences in agency and provider characteristics on OHCA outcomes deserves study. © 2011 Elsevier Ireland Ltd. All rights reserved.
1. Background Cardiovascular disease is a leading cause of death in the United States.1 While prevention and treatment regimens have reduced morbidity and mortality resulting from cardiovascular disease, the incidence and survival outcomes of Out-of-Hospital Cardiac Arrest (OHCA) have not improved during the same period.2
夽 A Spanish translated version of the abstract of this article appears as Appendix in the final online version at doi:10.1016/j.resuscitation.2011.06.026. 夽夽 Poster presentation at the National Association of Emergency Medical Services Physicians Annual Meeting, Phoenix, AZ, January 2010 and 13th Annual SAEM Western Regional Research Forum, Sonoma, CA, March 2010. ∗ Corresponding author. Tel.: +1 415 353 8213; fax: +1 415 353 1799. E-mail address: [email protected] (P. Govindarajan). 0300-9572/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.resuscitation.2011.06.026
In addition, significant regional and temporal variability in survival has been reported for OHCA some of which have been attributed to differences in case definitions, disparities in care among communities and secondary prevention of conditions leading to OHCA.3,4 However, even after controlling for these factors, unexplained differences in cardiac arrest survival persist, highlighting the need for further research into the reasons for this geographic variability.2 Rates of by-stander cardiopulmonary resuscitation (CPR), socio-economic status, community defibrillation programs and emergency medical services (EMS) agency factors (e.g. experience of providers and differences in treatment protocols) are factors hypothesized to be associated with this variability.5–7 Of the aforementioned factors, prehospital systems would benefit from studies that focus on identifying EMS agency and provider factors in the out of hospital setting that could have an impact on survival to discharge. It is important to understand these factors
P. Govindarajan et al. / Resuscitation 83 (2012) 76–80
and their distribution across EMS agencies since these are potentially modifiable and an important part of OHCA care. Therefore, in this study we describe the demographic differences and practice variations among EMS agencies in the CARES network. 2. Methods 2.1. Study design and population This is a descriptive study of the EMS agencies participating in the Cardiac Arrest Registry to Enhance Survival (CARES) registry using a web based survey (Survey Monkey). All CARES participating agencies in 2008 were invited to participate. 2.2. Cardiac Arrest Registry to Enhance Survival (CARES) CARES is a central repository of OHCA data from EMS agencies throughout the United States and is a collaborative effort between Centers for Disease Control and Prevention (CDC), Emory University, the Southeastern Affiliate of the American Heart Association, and Sansio Corporation (Duluth, MN). The registry serves as a quality improvement project and allows EMS agencies to compare key performance indicators to improve out-of-hospital cardiac arrest care. EMS agencies participating in the registry provide data elements related to OHCA from their 911 dispatch centres, EMS providers, and receiving hospitals. A description of the CARES methodology has been previously published.8,9 2.3. Study survey A structured questionnaire was developed by authors (CS, JM), who are experts in cardiac arrest care and emergency medical services delivery. Face validity was assessed by the study team and the survey was pilot tested by a subset of CARES site coordinators. The survey instrument was distributed by the research coordinator (AC) to the CARES co-ordinators who were emergency medical technicians/paramedics or nurse providers in charge of quality assurance for their agency. The eligible study population included EMS agencies contributing data to CARES as of April 2008. Survey questions addressed three domains related to out-of-hospital care: (1) descriptors of the participating EMS agencies, (2) methods of clinical care and clinical protocols used by EMS agencies to deliver out-of-hospital cardiac arrest care, (3) use of resuscitation techniques by EMS agencies serving CARES sites. (Appendix 1 presents a complete version of the survey questionnaire.) Follow up email and telephone calls were made to improve rates of survey completion and to answer any questions related to incomplete or missing responses. Survey responses were completed by the site administrative staff associated with the CARES project and reviewed by the authors (PG, LL) and CARES project coordinator (AC). All survey responses were collected, stripped of EMS agency identifiers, and entered into a Microsoft Excel 2007 database (PG, LL) (Microsoft Corporation, Redmond, WA). Data was analyzed in aggregate. Results are presented as mean with standard deviation, and medians and interquartile ranges when averages could not be calculated. Analysis was descriptive with no additional inferential statistics. 3. Results Twenty five agencies were members of the network at the time of this survey. Of those, twenty one sites (84%) responded to the survey; one agency did not complete the resuscitation techniques
77
Table 1 Characteristics of the EMS agency participating in CARES. n (IQR) Median number of 911 calls received by the communities Median number of emergency medical dispatches within the communities Median transport volume Median number of hours of ambulance coverage among EMS agencies
64,845 (20250,82604) 64,972 (24329,76032) 43,769 (11718,53277) 366 (204,559) n/N (%)
Response areas served by the EMS agencies Urban only Suburban only Urban and suburban Urban and rural Urban, suburban and rural Organizational type of EMS agencies Community non-profit agency Fire based agency Governmental third service (non-fire) based agency Hospital agency Private non-hospital based agency Medical direction statusa Salaried Contract Volunteer Full-time Part-time Review by committee More than one type of medical direction status Deployment status Fixed Dynamic a
3/21 (14%) 4/21 (19%) 5/21 (24%) 1/21 (5%) 8/21 (38%) 1/21 (5%) 9/21 (43%) 6/21 (29%) 2/21 (10%) 3/21 (14%) 11/21 (52%) 10/21 (48%) 1/21 (5%) 6/21 (29%) 6/21 (29%) 1/21 (5%) 12/21 (57%) 12/21 (57%) 12/21 (43%)
Total exceeds 100% due to overlap between categories.
section of the survey. The details of the participating sites can be found at https://mycares.net.9 3.1. Study survey questionnaire 3.1.1. Description of the CARES communities The descriptors of the CARES survey respondents are described in Table 1; 20/21 (95%) agencies serve sites with a population of more than 50,000 people (range 58,000–2.1 million) and 14/21 (67%) of the survey respondents report a population density of >1000 persons/square mile based on the 2000 U.S. Census population estimate. While all sites meet the criteria of the urbanized areas/urban clusters based on the official U.S. Census Bureau definitions, 9/21 (43%) survey respondents reported serving a combination of rural and urban areas and 5/21 (24%) reported serving a combination of urban and suburban areas.10 3.2. Characteristics of EMS agencies Emergency medical dispatch and the transport volumes for the agencies varied widely (Table 1). Five types of EMS service models serve the CARES sites. Nine (43%) sites are served by fire department-based EMS service providers and six sites (29%) are supported by non-fire-based EMS agencies. All respondents are non-volunteer organizations. Approximately one-third (6/21) of the EMS agencies within CARES have full-time medical directors and another third of the EMS agencies had part-time medical directors (6/21). More than half (57%) of the agencies have various sources of medical direction (i.e. single director, review committee, management committee). About 50% (n = 12/21) of the agencies use a fixed deployment model to deliver emergency services, where resources respond from a pre-designated and fixed location (e.g. fire station). Another 43% use dynamic deployment strategies, where the locations of specific ambulances are con-
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Fig. 1. Practice variation in out of hospital management of cardiac arrest among surveyed EMS agencies.
stantly redistributed according to overall system demand and resource availability. Although EMS agencies were of different organizational types, advanced life support response assignment configuration was similar. 3.3. Characteristics of EMS providers as reported by CARES agencies The survey respondents reported a total of 198 first responder units and 4556 paramedics during the study period. Of the total number of first responder units, number of first responder basic life support trained units (n = 112) was higher than automated external defibrillation first responder units (n = 45) or advanced life support units (n = 72). While the total numbers of paramedics varied widely among the agencies (range 25–664/EMS agency), no relationship was observed between the number of paramedics and total population served. The fire-based agencies have a slightly higher median number of paramedics [n = 230 (IQR 189, 325)] compared with non-fire based agencies [n = 200 (IQR 80, 219)], hospital-based [n = 93 (IQR 61, 122)], and non-hospital-based agencies [n = 206 (IQR 103, 181)]. Twelve agencies (57%) within CARES reported that majority of their EMS providers have at least five years of experience. More than half the number of agencies (57%) reported having at least 75% of their paramedics working full time. 3.3.1. Cardiac arrest management by EMS agencies Our results show wide variations in the protocols utilized for the care of cardiac arrest patients (Fig. 1). Protocol differences among dispatch centres were reported by EMS agencies including the ability to direct 911 callers to an automated external defibrillator (10/21 are able to do so). Ninety percent of the emergency medical dispatch centres among survey respondents reported providing pre-arrival CPR instructions; 95% of the EMS agencies reported
incorporating a quality review program that reviews emergency medical dispatcher instructions. EMS agencies have heterogeneous protocols for OHCA management, including implementation of 2005 ACLS guideline updates, cardiopulmonary resuscitation (CPR) procedures, and prehospital destination criteria for OHCA. About half (52%) of the agencies had modified the 2005 ACLS guidelines largely involving medication administration, airway and ventilatory strategies. Fourteen (67%) agencies reported continuing CPR for 2 min even with preceding bystander CPR. Only six of the surveyed respondents (29%) performed CPR before rhythm check in EMS-witnessed cardiac arrest, while four (19%) reported performing CPR during automated external defibrillator rhythm analysis. Seventeen of 21 (81%) respondents currently have a termination of resuscitation (TOR) protocol. Eighteen of the 21 (86%) agencies performed post-return of spontaneous circulation EKGs and nine reported (43%) triaging these patients to specific destination (resuscitation) hospitals. From a quality improvement (QI) perspective, less than half (43%) of the agencies provided feedback to their supporting first-responder agencies. Approximately a third (27%) supplied summary reports to participating hospitals. Feedback to individual providers was more commonly reported, but was not universal (57%).
3.3.2. Resuscitation techniques use among CARES agencies Similar to the variation noted in field management of OHCA, the use of resuscitation techniques varied widely among EMS agencies. We surveyed the EMS agencies on use of six resuscitation techniques: alternate airways, intraosseous lines, external compression devices, impedence threshold devices, field hypothermia implementation, and real-time CPR feedback devices. Overall, every agency used at least one of these techniques, while no agency used all six techniques. Table 2 provides a summary of resuscitation techniques use by CARES agencies. Alternate
P. Govindarajan et al. / Resuscitation 83 (2012) 76–80 Table 2 Resuscitation techniques among EMS agencies participating in CARES. Resuscitation techniques Alternate/blind airway insertion devices Intra-osseous Field hypothermia External compression device Impedance threshold device (ResQ Pod)
Currently using Num (%)a 19 (95%) 14 (70%) 10 (50%) 9 (45%) 7 (35%)
Years Median (IQR) 5 (2, 11) 2 (1, 3) 0.75 (0.5, 1) 4 (1.5, 4) 2 (2, 2)
a One EMS agency did not respond to the resuscitation techniques questions, leaving a sample size of 20 communities for this section.
airway devices and intraosseous lines are used in 19/20 (95%) and 14/20 (70%) of agencies, respectively. Real-time CPR feedback devices were only used by 2/20 (10%) agencies. External compression devices and alternate airway devices have been in use the longest, for four and five years, respectively. Field hypothermia implementation was the most recently added resuscitation technique. Resuscitation techniques may not be uniformly used in all OHCA, even when the device is available. All agencies that used real-time CPR feedback devices and impedance threshold devices used them in greater than 50% of OHCA. However, <20% of agencies using alternate airway devices and field hypothermia implementation used them in over 50% of OHCA patients. 4. Discussion The communities served and care delivered by EMS agencies participating in CARES differs in many respects. Important areas of variability include agency organizational structure, field management of OHCA, and use of resuscitation techniques. A similar variation was observed among EMS agencies serving the sites participating in the Resuscitation Outcomes Consortium (ROC) network, a clinical trial network created to focus research in the area of prehospital cardiac arrest and traumatic injury.11,12 However, this is the first study to report inter-agency differences for a specific disease process, i.e. OHCA. Demographic differences noted among the communities include size and population of the community and the density of the population. Differences were also observed among the agencies in the volume of 911 calls, EMS transports and the number of advanced life support providers. Although there were significant variations in the numbers of EMS providers, no clear relationship was observed with the total population or the transport volume. While some of this could be explained by the higher number of personnel serving densely populated areas rather than areas with larger population, future studies should identify the staffing pattern and provider configuration associated with favourable OHCA outcomes. In EMS systems, optimization of rapid first response provided by emergency responders such as police or fire-fighters has shown to improve survival in OHCA.13 In our study among the survey respondents, first responders consisted of providers trained in automated external defibrillation only, basic life support techniques and advanced life support techniques. Although a landmark Canadian study showed that in an already optimized defibrillation system, Advanced Life Support Services did not improve survival in OHCA subjects, this model has not been widely adopted by many of the EMS agencies within our network.14 Therefore, future studies using CARES should assess barriers that limit adoption of evidence based models and help to improve efficiency and effectiveness of OHCA management in the prehospital setting. We also found that dispatch-assisted instructions for CPR and directing callers to the closest AED varied widely among our sites. While published literature has shown that dispatch-assisted
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instructions are known to increase rates of bystander CPR and therefore associated with good outcomes the impact of other medical dispatch factors such as dispatcher experience and capabilities such as directing the caller to automated external defibrillator and presence of quality improvement programs on outcome variability are yet to be studied.15 Other significant findings in our study include the wide variability in adherence to clinical guidelines for management of OHCA among agencies. Many EMS agencies adhere to the most current ACLS guidelines, whereas half of survey respondents modified the guidelines in local protocols. Some of these differences are likely due to the agencies being “early adopters” of resuscitation techniques. Guidelines are updated every five years and may take another year for dissemination. Therefore, agencies may modify protocols based on new knowledge available prior to guideline development. Future studies should study the impact of adherence to guidelines on clinical outcomes. Our study also discovered the differences in the use of resuscitation techniques across the EMS agencies as well within individual community arrests. The 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care supported use of in-hospital hypothermia in unconscious adults with spontaneous circulation after OHCA.16 Although pre-hospital initiation of hypothermia may enhance survival, the magnitude has not been described in published studies.17 Alternative airway devices and intra-osseous lines are supported by published studies and endorsed by the 2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.16 These three devices were used by the majority of communities participating in this study suggesting these communities are applying evidence-based medicine and AHA recommendations. However, within each community, alternate airway devices, intra-osseous lines, and field hypothermia were not uniformly applied in individual arrests. While some of this may be related to the evidence supporting use of techniques in only specific causes of arrests, other provider factors such as experience of the providers in the use of devices and training in the use of devices to improve outcome benefits must be explored. We observed that EMS agencies in our study population followed some of the AHA recommendations for resuscitation techniques. However, as resuscitation science evolves and updated AHA guidelines are released, resuscitation techniques uses will likely also change. Therefore, future studies may be able to harness CARES data to evaluate the impact of combinations of resuscitation techniques uses on OHCA outcomes. 4.1. Limitations One of the major limitations is that the survey was administered to EMS agencies participating in the CARES network. Since EMS agencies participating in CARES are a self-selected group, they may be systematically different from non-participants. Therefore, the differences observed in this group may not be similar to the non-CARES communities. However, we believe that this is a good starting point since the agencies serve a geographically diverse assortment of communities across the United States and are comprised of many different system designs. Although we have reported data from dispatch centres, this information was not obtained by an independent survey of the dispatch agencies and may be subject to sampling bias. The agency representatives who responded to the survey are knowledgeable about all aspects of OHCA care, including emergency medical dispatch procedures. Lastly, survey data is primarily self-reported, and subject to missing information, non-availability of data, and variability in interpretation of the survey questions. Although some of this
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improved after follow up calls to the agency contacts by the CARES coordinator, we were still left with some missing data in this study. 5. Conclusion Within an existing quality improvement network for OHCA, we have identified differences in the organizational and provider characteristics of the participating EMS agencies and in the protocols and devices used in managing resuscitations. Future studies will need to be conducted to assess which EMS and provider factors are most closely associated with increased survival, with the hope that this information can lead to “best practices” that can be adopted by all EMS agencies. This better understanding of the interplay between EMS characteristics and patient outcomes will hopefully improve OHCA survival. Conflict of interest statement Dr. Govindarajan is a member of the Stroke Task Force, Western States Affiliates, American Heart Association. None of the authors have any conflict of interest. Study contribution PG, CS, JM, BM and AL conceived the study and CS and JM designed the survey instrument. PG, AC and LL collected the data, PG and LL analyzed the data. PG, JM and AL drafted the manuscript, and all authors contributed substantially to its revision. PG takes responsibility for the paper as a whole. Acknowledgements The authors would like to acknowledge the CTSI-K program faculty mentors and peer reviewers, University of California, San Francisco for their feedback on the manuscript and Amy Markowitz, JD for her editorial assistance with this manuscript. Role of funding source: Dr. Govindarajan is supported by a career development award from the Agency of Healthcare Research and Quality K08 HS 017965-02 and Stroke Division of the American Heart Association, Western States Affiliate Clinical Research Program. The funding source has no role in the study design, in the collection, analysis and interpretation of data; in the writing of the manuscript; and in the decision to submit the manuscript for publication.
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