Outcomes from out-of-hospital cardiac arrest in Detroit

Transcription

1 Resuscitation (2007) 72, CLINICAL PAPER Outcomes from out-of-hospital cardiac arrest in Detroit Robert B. Dunne a,, Scott Compton a,b,c,d, R.J. Zalenski b, Robert Swor c, Robert Welch d, Brooks F. Bock d a Department of Emergency Medicine, Sinai-Grace Hospital, b Department of Emergency Medicine, John D. Dingell VA Hospital, c Department of Emergency Medicine, William Beaumont Hospital, d Department of Emergency Medicine, Detroit Receiving Hospital, Received 7 October 2005; received in revised form 14 April 2006; accepted 14 April 2006 KEYWORDS Out-of-hospital CPR; Emergency medical services; Adult; Cardiac arrest Summary Objective: To determine the out-of-hospital cardiac arrest survival rate, and prevalence of modifiable factors associated with survival, in Detroit, Michigan, over a 6-month period of time in Methods: A retrospective review of all out-of-hospital cardiac arrests responded to by the Detroit Fire Department, Division of Emergency Medical Services. All elements of the EMS runsheet were transcribed to a database for analysis. Patient hospital records were reviewed to determine survival to hospital admission. All survivors to hospital admission were surveyed later in the Michigan Department of Vital Records death registry search. Results: During this study timeframe, there were 538 confirmed out-of-hospital cardiac arrests within the City of Detroit, of which 67 were excluded for being dead on scene [51 (12.5%)] or having no available hospital records [16 (3.0%)]. Of the remaining 471 patients, 443 (94.1%) died before hospital admission. Only 44 (9.9%) of the 471 patients had a first recorded rhythm of ventricular fibrillation (VF), and 339 (76.5%) were asystolic. Of the 28 patients who survived to hospital admission, only 2 (7.1%) were noted to have a first rhythm of VF, and 15 (53.6%) were asystolic. Only one patient survived to hospital discharge. Conclusions: In this urban setting, out-of-hospital cardiac arrest is an almost uniformly fatal event Published by Elsevier Ireland Ltd. A Spanish translated version of the summary of this article appears as Appendix in the final online version at doi: /j.resuscitation Corresponding author at: 4201 St. Antoine, UHC-6G, Detroit, MI , United States. Tel.: ; fax: address: rdunne@med.wayne.edu (R.B. Dunne) /$ see front matter 2006 Published by Elsevier Ireland Ltd. doi: /j.resuscitation

2 60 R.B. Dunne et al. Introduction A tremendous amount of public resources are spent on planning for, and responding to, out-ofhospital cardiac arrests. These resources include layperson training programs for cardiopulmonary resuscitation (CPR), emergency medical service (EMS) equipment and training, and more recently, publicly accessible automated external defibrillators (AEDs). There is a large body of literature that supports these factors as being associated with survival from out-of-hospital cardiac arrest. This includes provision of bystander CPR, and a rapid EMS response providing early defibrillation. 1,2 Interestingly, however, in the largest study of the impact of an advanced cardiac life support EMS system ever published, no benefit on survival from cardiac arrest was identified. 3 Despite the dramatic increase in public resources commissioned in the past 40 years to respond to cardiac arrests, no evidence exists that suggests there has been a commensurate increase in the overall survival rate. The low survival rate in of cardiac arrest patients reported from cities such as New York City 4 and Chicago 5 in the early 1990s persist in the more recently published results from Los Angeles. 6 Given these reported mortality rates, and our clinical experience, we designed a study to estimate the survival rate from nontraumatic cardiac arrest in the City of Detroit, Michigan. We therefore instituted a non-traumatic cardiac arrest registry for 6 months in 2002 to evaluate both the survival rate and the prevalence of modifiable factors known to improve out-of-hospital cardiac arrest survival. Methods The Detroit Cardiac Arrest Registry (D-CAR) was designed as a retrospective observational cohort study of all adult out-of-hospital cardiac arrests within the City of Detroit. All EMS run sheets generated between 1 January 2002 and 30 June 2002 were obtained from the Detroit Fire Department Division of EMS. These records were searched by three research assistants, with overlapping review, to detect all records with EMS dispatch information or chief complaint described as: cardiac arrest, found down, not breathing, heart attack, or unconscious. Additionally, all records indicating CPR provision or advanced cardiac life support (ACLS) procedures were also included, to obtain information on possible EMS witnessed arrests. All data elements from the EMS records were entered into a Microsoft Access database specifically designed to match the EMS record, and later exported to SPSS (Chicago, IL) for analysis. Each record was reviewed by three investigators (RD, SC, JW) for data completion and validity. Through the above process, a database of all adult ( 18 years) out-of-hospital cardiac arrest patients, and the receiving hospital that they were transported to, was compiled. The emergency department records for these patients were then reviewed for survival to hospital admission. All patients were classified with regard to death in the emergency department and survival to hospital admission. Information on patients, admitted to the hospital, or for whom no emergency department record could be found, were submitted to the Michigan Department of Vital Records for a death registry search. Patients who survived to hospital admission, and whom were not listed in the death registry within 60 days of the hospitalization, were recorded as survivors. This study was approved by the Wayne State University Human Investigations Committee, and by each receiving hospital. Results According to the 2000 United States Census, the City of Detroit is approximately 139 square miles, with 6855 persons per square mile. In 2002, Detroit s population was approximately 950,000 people, of which approximately 10% were 65 years or older. There were approximately 375,000 housing units. Median household income was approximately $30,000, and many residents (26.1%) were living below the poverty level. Residents of the city are predominantly Black (81.6%). During the 6-month study period, there were 62,261 EMS dispatches, and 34,244 transports. Of these, 538 were identified as adult, nontraumatic, out-of-hospital cardiac arrests. This incidence of cardiac arrest (99.1/100,000/year) given the population size and time of study corresponds with published estimates of New York City, 4 Chicago, 5 and Los Angeles. 6 As shown in Figure 1, of the 538 identified cases, 67 (12.5%) were excluded. These exclusions consisted of either pronouncement of death on scene [51 (9.5%)], which in this system requires evidence of advanced rigor or decomposition, or patients listed as dead with no available identifiers [16 (3.0%)].

3 Outcomes from out-of-hospital cardiac arrest in Detroit 61 Figure 1 Out-of-hospital cardiac arrests (OHCAs) 1 January 2002 through 30 June Patient characteristics As shown in Table 1, patients were predominantly Black (70.9%), and arrests most frequently occurred in private residences (79.0%). Mean patient age was 63.3 years (±17.2). Few arrests were witnessed by EMS personnel [24 (5.1%)], and none of these survived to hospital discharge. EMS response characteristics Mean response interval, defined as the time that the EMS ambulance received the call and the time of arrival at the designated address, was 8.36 min, and a response of less than 6 min was noted in 38.1% of all cases. All responding units were ALS ambulances as there are no first responders in this system. This response covered a mean of 3.8 miles to scene (minimum 0, maximum 15). EMS response characteristics are shown in Table 2. Figure 2 describes characteristics of included cardiac arrest cases. Bystander witness information was not available for 56 (12.5%) of 447 non-ems witnessed arrests. The majority (64.5%) of the remaining arrests were not witnessed by a bystander. Of 471 patients, 443 (94.1%) died before hospital admission, 44 (9.9%) of those patients had a first recorded rhythm of ventricular fibrillation (VF), and 339 (76.5%) were asystolic. Sixty-nine patients (14.5%) received cardiac defibrillation. Data for time to first shock was available for 66 of these, average time from EMS receipt of the call to the first shock averaged 14 min. Defibrillation in less than 8 min was achieved in 19 (28.8%). Only 34 (7.2%) patients were noted to have a return of spontaneous circulation in the prehospital setting. Survival There were 28 (5.9%) patients who survived to hospital admission. Of those, only 2 (7.1%) were noted to have a first rhythm of VF, and 15 (53.6%) were

4 62 R.B. Dunne et al. Table 1 Patient characteristics Table 2 EMS response characteristics Characteristics Gender, n (%) Male 238 (50.5%) Female 233 (49.5%) Age, years (n = 462; 9 missing) Mean (S.D.) (17.2) Median (IQR) ( ) Minimum maximum Race, n (%) Black 334 (70.9) White 45 (9.6) Asian 6 (1.3) Hispanic 3 (0.6) Other 1 (0.2) Unknown 82 (17.4) Location, n (%) Private residence 372 (79.0) Public location 35 (7.4) Doctor s office 11 (2.3) Convalescent center 34 (7.2) Other 19 (4.0) asystolic. Only one (0.2%) patient survived to 60 days post admission. Discussion This study documents an almost uniformly fatal outcome from out-of-hospital cardiac arrest in this community. Out-of-hospital cardiac arrest remains a major cause of mortality for adults in the United States. 7 The evolution of the treatment of cardiac arrest has paralleled and in many ways has been responsible for the growth of emergency medical services. Strategies to improve survival have driven improvements in education and equipment for prehospital responders. The majority of the population in the United States lives in metropolitan areas. In New York City, Los Angeles and Chicago EMS systems cardiac arrest survival rate is low. 4 6 Hong Kong also reports a 1.25% survival rate. 8 The OPALS group in Canada report an overall 4.6% survival rate. 9 Rochester, MN reported 40% neurologically intact survivors of 200 patients with ventricular fibrillation, mean time to defibrillation was 5.7 min. Of their non V-fib group there were only four survivors out of Many factors affecting cardiac arrest survival are independent of the EMS system, including rate of bystander CPR, patient demographics, time from collapse to activation of the 911 system, and availability of rapid defibrillation. 11,12 Recent literature has examined the effect of public EMS characteristics EMS miles to scene (n = 469) Mean (S.D.) 3.81 (2.6) Median (IQR) 3.00 ( ) Minimum maximum 0 15 EMS response time a (n = 470) Mean (S.D.) 8.36 (4.5) Median (IQR) 8.00 ( ) Minimum maximum 0 36 Response 6 min, n (%) 179 (38.1) EMS first recorded rhythm, n (%) V-Fib 46 (9.8) V-Tach 4 (1.1) Asystole 354 (75.2) PEA 47 (10.0) Sinus 13 (2.8) Idio-ventricular 5 (1.1) Missing 1 (0.2) Number of shocks provided, n (%) (85.4) 1 21 (4.5) 2 12 (2.5) 3 19 (4.0) 4 9 (1.9) 5 2 (0.4) 6 3 (0.6) 7 2 (0.4) 8 1 (0.2) EMS time to first shock (n = 66) Mean (S.D.) (7.5) Median (IQR) ( ) Minimum maximum 4 45 First shock 8 min, n (%) 19 (28.8) Prehospital ROSC, n (%) Yes 34 (7.2) No 385 (81.7) Not recorded 52 (11.0) a Note: EMS response time is defined as the number of minutes between the EMS call reception and time to arrival at address. access defibrillation 13 and examined the implementation of certain aspects of ALS care in a structured fashion. 2,3 Our system is unique among 200 cities in listed in the Journal of Emergency Medical Services annual survey, in that there is no first response system. 14 All ambulances at the time of this initial collection of data for the Detroit Cardiac Arrest Registry (DCAR) were ALS with at least one paramedic and one basic EMT on the vehicle. EMS is a division of the fire service but operates under a different collective bargaining agreement and there is strict separation between fire suppression assets

5 Outcomes from out-of-hospital cardiac arrest in Detroit 63 Figure 2 Study sample flowchart. and EMS responders. There are no fire-fighter medical responders. Pharmaceutical boxes carried by EMS have been updated to accommodate changes in ACLS algorithms. Hospitals in the city have individually participated in resuscitation studies in the past with low reported survival. 15 Unpublished data from 1987, shortly after deployment of automated defibrillators with basic EMT s, reported 594 arrests and no survivors to hospital discharge. 16 Many municipalities around the world have reported cardiac arrest data using the now standard Utstein Style. 17 Cardiac arrest survival has been used as a quality benchmark for many EMS systems and has driven the development of prehospital advanced life support. 18 Survival from outof-hospital cardiac arrest is very low in our system, in fact lower than is reported in other large metropolitan areas. 4 6 The low rates of ventricular dysrythmia in our study population may related to problems with recognition of cardiac arrest and perhaps a long collapse to call interval. There is also a low rate of bystander CPR, a longer time before first defibrillation, and a high prevalence of asystole as presenting rhythm. Other factors, not specifically examined or documented in the record, such as severe underlying disease may play a part

6 64 R.B. Dunne et al. in decreased survival. Detroit residents have a high prevalence of hypertension, coronary artery disease, diabetes and renal failure. We do not have consistent data regarding the socioeconomic characteristics of the cardiac arrest victims but Detroit has a large number of families below the poverty level. Effecting change on the factors that lead to decreasing cardiac arrest survival is challenging. Urban areas in the United States, including Detroit, face budget crises which limit options. Health care spending and access to care is consistently decreasing for the urban population and more cuts are proposed. In the 2 years before the study period two large hospitals closed, since the end of the study period another hospital has eliminated its inpatient unit and become a free standing emergency department not taking resuscitation patients. This may affect overall response time intervals in the city, because units have to travel farther and spend more time from scene to hospital delaying the time they are available for service. The city has tried adding a few non-transporting EMS units that are simultaneously dispatched with transporting units and these have been observed to occasionally arrive sooner [personal communication Detroit EMS Chief G. Kelly]. There is not enough data on these at this time to determine if there is an effect on out-of-hospital cardiac arrest. There is an increasing demand for a fire based first response system but no specific plan is in place at this time. More CPR training may result in increased rates of bystander CPR and may also increase awareness of cardiac arrest and need for prompt 911 activation. Additional changes may benefit the system and improve survival from out-of-hospital cardiac arrest. Rarely are any patients declared dead in the field after resuscitation is started. Clearly those in our study who had asystole as initial rhythm had a survival rate of 0% and efforts could have been terminated in the field. This would necessitate some changes in the support system available from law enforcement and the medical examiner to rapidly care for the dead in a sensitive manner. Units that did not transport could get back into service more rapidly and be available for other runs. Decreasing the number of very low priority runs that the ALS units are involved in responding to and transporting may increase the ALS availability and impact out-of-hospital cardiac arrest. This solution has proved challenging in Detroit and elsewhere. 19 Public access defibrillation is not likely to affect overall survival. There are no large regular gathering places in the city that are not already staffed by responders. EMS leadership in the city has long been concerned that any examination of data results in blame and criticism and not meaningful improvement. The department s cooperation with this study represents a step forward and open discussion of data can drive positive changes in the system. Additional information on other aspects of our EMS system needs to be collected. Although out-ofhospital cardiac arrest survival is reported to be a common marker of EMS system quality, the multitude of factors in the urban environment may limit the improvement in survival rates. Conclusion The results of this study demonstrate that survival in an urban ALS system with no first responders is very low, but similar to other major metropolitan communities that do have first responders. This is the first systematic examination of cardiac arrest in the Detroit EMS system and provides the basis for future studies which may capitalize on the noted opportunities for improvement. Conflict of interest statement There are no conflicts of interest for any of the authors. Acknowledgement Supported by a grant from Wyeth-Ayers. References 1. 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(1): Stiell IG, Wells GA, Field BJ, et al. Improved out-of-hospital cardiac arrest survival through the inexpensive optimization of an existing defibrillation program: OPALS study phase II. Ontario Prehospital Advanced Life Support. JAMA 1999;281(13): Stiell IG, Wells GA, Field B, et al. Advanced cardiac life support in out-of-hospital cardiac arrest. N Engl J Med 2004;351(7): Lombardi G, Gallagher J, Gennis P. Outcome of outof-hospital cardiac arrest in New York City. The Pre- Hospital Arrest Survival Evaluation (PHASE) Study. JAMA 1994;271(9): Becker LB, Ostrander MP, Barrett J, Kondos GT. Outcome of CPR in a large metropolitan area where are the survivors? Ann Emerg Med 1991;20(4):

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