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Prehospital care
Out-of-hospital cardiac arrest in Cork, Ireland
  1. Kieran Henry1,
  2. Adrian Murphy2,
  3. David Willis1,
  4. Stephen Cusack2,
  5. Gerard Bury3,
  6. Iomhar O'Sullivan2,
  7. Conor Deasy4
  1. 1National Ambulance Service, Cork, Ireland
  2. 2Department of Emergency Medicine, Cork University Hospital, Ireland
  3. 3Department of General Practice, University College Dublin, Ireland
  4. 4Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia
  1. Correspondence to Kieran Henry, National Ambulance Service, H.S.E. Southern Region, South Link Road, Cork, Ireland; henrykieran{at}gmail.com

Abstract

Background Out-of-hospital cardiac arrest (OHCA) in Ireland accounts for approximately 5000 deaths annually. Little published evidence exists on survival from OHCA in this country to date. We aimed to characterise and describe ‘presumed cardiac’ OHCA in Cork City and County attended by the Ambulance Service.

Methods Dispatch records, ambulance patient records and hospital records for a 1-year period were examined for patient demographics, OHCA characteristics, interventions and patient outcomes.

Results There were 231 ‘presumed cardiac’ OHCAs attended over the study period; 130 (56%) were in urban locations and 101 (44%) in rural. OHCAs were lay-witnessed in 20% (n=46), and 22% (n=50) received bystander CPR. Shockable rhythm was present in 36 cases (16%) on initial assessment, and there was no difference in presence of shockable rhythm between urban and rural OHCAs (18% vs 13%, p=0.31). Resuscitation was attempted in 176 cases (77.5%), of whom 27 (15%) achieved return of spontaneous circulation and 13 (7.4%) survived to leave hospital. Survival when the initial rhythm was shockable was 16.7% (6 of 36 patients). Despite longer response times for rural compared with urban OHCAs (median (IQR) 16.5 (11.0–23.5) vs 9 (7–12) min, p<0.001), survival to leave hospital alive where resuscitation was attempted was similar (7.4% vs 7.4%, p=0.99, respectively).

Conclusion A survival rate of 16.7% in shockable rhythms indicates scope for improvement which would influence the overall survival rate which was found to be 7.4%. Real-time feedback of performance and quality of the continuum of patient care through a clinical-quality cardiac arrest registry would monitor and incentivise such initiatives.

  • Cardiac arrest
  • pre-hospital
  • outcome
  • rural
  • urban
  • OHCA
  • emergency services
  • registry
  • basic ambulance care
  • doctors in PHC
  • emergency ambulance systems
  • anaesthesia
  • acute coronary syndrome
  • cardiac care
  • treatment
  • CBRN
  • ethics
  • epidemiology
  • education
  • paramedics
  • trauma
  • major trauma management
  • alcohol abuse
  • resuscitation
  • clinical care
  • ultrasound
  • effectiveness
  • training

http://dx.doi.org/10.1136/emermed-2011-200888

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    Introduction

    In Ireland, approximately 5000 people die each year as a result of out-of-hospital cardiac arrest (OHCA).1 Early cardiopulmonary resuscitation (CPR) and defibrillation improve survival. In their absence, brain death begins 4 min after cessation of cardiac output.2 The European Society of Cardiology Task Force recommends a target time from emergency call to defibrillation in OHCA of less than 5 min.3

    Survival rates from OHCA in Ireland are unclear with little published evidence; the 2005 Sudden Cardiac Death report estimated national survival rates at <5% and recommended a wide range of community and professional initiatives to improve the situation.1 Some local communities in Ireland are funding public-access automated external defibrillator programmes. The government, through the Health Service Executive (HSE) offers training programmes to voluntary groups with the aim of improving response times to OHCA.

    The HSE National Ambulance Service provides all emergency ambulance responses in the Cork City and County area. The aim of this study was to analyse all ‘presumed cardiac’ OHCAs in Cork City and County which received an HSE Ambulance Service response over a one-year period (from 1 September 2007 to 31 August 2008). This retrospective, observational study examined patient demographics, prehospital clinical interventions, incident location, ambulance service response times and patient outcome.

    Methods

    Ireland uses the 999 or 112 telephone numbers as national access points to all emergency services. Paramedics are trained in basic life support, defibrillation and supraglottic airway insertion. They are permitted to administer a limited range of medications including intramuscular glucagon and epinephrine, nebulised salbutamol, aspirin and sublingual nitrates. The Health Service Executive (HSE) National Ambulance Service commenced training of Advanced Paramedics (APs) in 2004 and now has 147 trained APs deployed nationally on front-line emergency vehicles (of a total workforce of around 2000). APs are trained to intubate in situations of cardiac arrest, and can administer cardiac resuscitation drugs such as epinephrine, atropine and amiodarone, according to Advanced Life Support (ALS) algorithms. APs are trained to perform intravenous and intraosseus access. Paramedics and APs use Clinical Practice Guidelines to inform the decision to not resuscitate or to cease resuscitation, and to guide all clinical interventions.4 In general, on-scene times are kept to a minimum, and patients are transported with cardiopulmonary resuscitation (CPR) in progress.

    The study region has a total population of 481 295 people with 119 418 (24.8%) in Cork City and 361 877 (75.2%) in the Cork County area, which has a broadly rural and dispersed community.5 The geographical area of Cork City and County is 7545 square kilometres, which represents 11% of the Irish State. Cork City has a population density of 3014.8 persons for every square km, while Cork County has a population density of 48.5 persons per square kilometre.6 The regional ambulance control centre for Cork used a Computer Aided Dispatch and an Integrated Command and Control System during this study period; however, structured call-taking, or dispatcher CPR instructions were not in place. Time of ambulance dispatch and arrival at scene were digitally recorded by a status button system linked electronically through a two-way radio system. There are two ambulance bases in Cork City and 11 bases in Cork County. All ambulances are staffed with paramedics, while APs respond to higher acuity calls in ambulances or rapid response vehicles.

    Patient Care Report (PCR) forms are completed by ambulance crews for all calls, and in the Cork area, all PCRs involving cardiac arrests are collected centrally. In addition, ambulance control staff note all cases involving cardiac arrest on a database. Non-traumatic OHCA data for the period September 2007 through August 2008 was collected from three sources by a single investigator (KH):

    • The regional ambulance control database

    • The ambulance service PCR forms

    • The in-patient medical records from the five receiving hospitals

    This data was then entered onto the Utstein data collection form7 ,8 which was adapted for use in this study. The Utstein elements are designed to assess links in the cardiac arrest chain of survival and provide the basis for comparing outcomes within and across communities; they include the age of the patient, whether the arrest was witnessed or not, whether bystander CPR was performed, length of time to Emergency Service arrival and patient outcomes. Out-of-hospital cardiac arrest (OHCA) is presumed to be of cardiac aetiology unless, as best determined by the rescuers, it is known, or likely to have been caused by trauma, submersion, drug overdose, asphyxia, exsanguination or other non-cardiac causes.8 The Cerebral Performance Category (CPC) score is an easy-to-use measure of functional outcome after cardiac arrest which can be ascertained from the patient's hospital record.9 A CPC score of 1 or 2 corresponds with independent living.

    There was excellent correlation between the control centre database of OHCAs and the centralised PCR collection of OHCAs. All information was manually written into the data collection form and subsequently transferred to a Microsoft Excel spreadsheet. Statistical calculations were performed on STATA software (V.10.0 Stata Corporation). Chi-square analyses were used for categorical variables. Continuous variables were compared using the t test (normal distribution) or Mann-Whitney test. Data which was not normally distributed, such as age and ambulance response times were reported with medians and interquartile ranges (IQR). Ethical approval was granted by the Cork Teaching Hospitals Ethics Committee.

    Results

    Ambulance control received 16 899 ‘999/112’ calls during the study period, of which 231 (1.3%) represented ‘presumed cardiac’ OHCAs. In 55 cases, resuscitation was not attempted as the patient had signs of rigor mortis, or a Registered Medical Practitioner (RMP) had declared the patient to be dead at the scene. Resuscitation was attempted in 176 cases (77.5%), 100 patients (56.8%) were transported to hospital, 27 patients (15%) achieved return of spontaneous circulation (ROSC) and 13 patients (7.4%) survived to leave hospital. Survival, when the initial rhythm was shockable, was 16.7% (6 of 36 patients). Table 1 shows the characteristics of survivors and non-survivors, and the OHCA characteristics and outcomes.

    View this table:
    Table 1

    Description of the characteristics of out-of-hospital cardiac arrest patients who survived to leave hospital alive compared with those who did not

    Collapse was recorded as ‘lay-witnessed’ in 20% of cases (n=46) attended by the Ambulance Service, and 25% (n=45) of those where an attempted resuscitation was performed. Data on the witnessed status of the arrest, however, was missing in the documentation of 40 cases. Bystander CPR was performed in 50 patients; this represented 22.3% of all OHCAs, and 29% of patients who had an attempted resuscitation.

    Patient demographics

    One hundred and forty-six patients (63.2%) who attended were male. The median and interquartile age range was 65 years (51–75 years).

    Incident location

    Of OHCAs attended, 165 (71.4%) occurred in the home, 21 (9.1%) occurred on a road or street, one (0.4%) case occurred in the workplace and 44 (19%) cases occurred in other places.

    Rural versus urban outcomes

    One hundred and thirty (56%) OHCAs occurred in the urban area, and 101 (44%) in the rural area. Ninety-six (74%) urban OHCA patients, and 83 (82%) rural OHCA patients received an attempted resuscitation by the Ambulance Service (p=0.133). The median (IQR) age of the urban OHCA patients was 63 (46–75) years, and for rural patients it was 67 (57–75) years (p=0.09). The initial rhythm was shockable in 23 urban OHCAs (18%), and 13 (13%) rural OHCAs, p=0.32. Rural OHCAs were more likely to be witnessed, 28.7% versus 13.1%, p=0.003, and more received bystander CPR, 29.3% versus 16.8%, p=0.03. There were seven (7.3%) urban and six (7.2%) rural survivors that left hospital alive (p=0.98).

    Ambulance Service response times

    The median (IQR) response time by the Ambulance Service was 11 (7–17) min. The urban median (IQR) response time was 9 (6–12) min, while the rural median (IQR) response time was 15 (10–23) min (p<0.001). The ambulance response time, where resuscitation was not attempted (n=55) was median (IQR) 10 (8–18) min.

    Clinical interventions

    ALS, that is, intubation and/or advanced cardiac life support medications was administered in 90 (51.1%) cases where the Ambulance Service attempted resuscitation (n=176) (table 2). Where ALS care was provided it was performed by an AP in 59 (65.6%) cases, an RMP in 15 (16.7%), and an AP and RMP in 16 (17.8%) cases. Fourteen (16%) patients who received ALS achieved ROSC, while 13 patients (15%) who received Basic Life Support (BLS) achieved ROSC (p=0.93). There were five (5.6%) patients who received ALS and eight (9.3%) patients who received BLS discharged alive from hospital (p=0.34).

    View this table:
    Table 2

    Frequency of interventions performed where resuscitation attempted (n=176)

    Patient outcomes

    Of the 176 patients in whom resuscitation was attempted, 13 patients (7.4%) survived to hospital discharge. The survival, when the initial rhythm was Ventricular Fibrillation/pulseless Ventricular Tachycardia (VF/VT), was 16.7% (6/30). Of the 13 survivors, 11 had a CPC score of 1, one patient had a CPC score of 2, and we were unable to ascertain the CPC in one other patient.

    Patient and OHCA characteristics where resuscitation was not attempted (n=55)

    The median (IQR) age of patients who did not receive an attempted resuscitation was similar to those who did (66 (50–75) years). Most were un-witnessed (n=61, 98%) and bystander CPR was rarely performed (n=2, 3.8%).

    Discussion

    This is the first study from Ireland to describe outcomes from OHCA identified through ambulance records. This retrospective observational study using a standardised data recording tool, the Utstein template, benchmarks performance and allows for future comparisons. It shows that despite a low density and dispersed population with the associated longer ambulance response times, survival to leave hospital was 7.4% for all resuscitation attempts, and 16.7% for OHCAs with a shockable rhythm. Survivors and non-survivors differed in this study by the higher levels of a shockable rhythm and bystander CPR among survivors.

    Ewy's recent editorial in Circulation stated that the survival for witnessed arrest with a shockable rhythm should approach 40%, and where it does not, room for improvement and changes in emergency medical service (EMS) protocols should not be delayed.10 The Cardiac Arrest Registry to Enhance Survival in the USA reports an OHCA survival rate of 8.5% for all rhythms;11 the Resuscitation Outcomes Consortium registry which includes 174 Emergency Service agencies in North America and Canada reports an overall survival rate of 6.1%;12 the Victorian Ambulance Cardiac Arrest Registry in Australia reports a survival rate of 11.8% ‘for presumed cardiac’ OHCA;13 and London Ambulance reports a survival rate of 8.7%.14 Measurement of cardiac arrest outcomes is an integral part of quality assurance and quality improvement, yet only a minority of EMS systems know the survival rate to hospital discharge for victims of OHCA cared for by their service.15 Measurement of performance and feedback is integral to improving patient care, particularly in this condition where, around the world, survival is the exception rather than rule,16 yet survival rates of 16.3% for all OHCAs and 40% for witnessed ventricular fibrillation OHCAs are reported in some areas.17 A successful outcome for victims of OHCA depends on several factors. Eisenberg summarised these as ‘patient’, ‘environmental’ and ‘system’ factors.18 Patient factors include preexisting health problems, and the cardiac arrhythmia associated with the collapse. Environmental factors include whether the collapse was witnessed or not, and whether bystander CPR was performed. System factors include the presence of community-based Cardiac First Responder schemes, access to a defibrillator, and a well-resourced, highly trained, and dynamic EMS. The ‘chain of survival’ concept, as pioneered by Peter Safar and described by Cummins et al in 1991,5 ,6 focuses attention on four critical links in the resuscitation process of a victim of OHCA:

    1. Early recognition and access to EMS

    2. Early CPR

    3. Early defibrillation

    4. Post-resuscitation care

    Different agencies and different disciplines are involved in the provision of care in each link of the chain of survival; Ambulance Service, General Practice, Emergency Medicine, Cardiology, Intensive Care and Rehabilitation. Herein lies a challenge, as these agencies and disciplines often work in isolation. While a study such as this offers an insight into performance across agencies and disciplines, real-time monitoring and feedback through a dynamic clinical-quality cardiac arrest registry19 would offer sustained quality assurance and incentivise quality-improvement measures. The establishment of Ireland's OHCAR will address many of these issues.

    Some aspects of the chain of survival in our system require refinement to achieve an improvement in outcome. To decrease response times, to ensure the appropriate level of response to a call and to increase bystander CPR rates, the region's Ambulance Service must have a reliable call-taking and dispatch system with high sensitivity and specificity for OHCA, and the capability to give telephone-assisted bystander CPR advice.20 Since this study was completed, a number of initiatives have been commenced. These include the use of the Advanced Medical Priority Dispatch System®, as well as public access defibrillation programs and civilian CPR programs coordinated by the Ambulance Service. In addition, there has been increased engagement between the statutory agency and voluntary services such as Red Cross and St John's Ambulance, as well as changes to rostering and deployment within the Ambulance Service in Cork. The post-resuscitation link in the chain of survival has also been improved with increased access to cardiac catherisation and therapeutic hypothermia in the region.

    Bystander CPR has been shown to improve survival and quality of life of survivors who sustain an OHCA.21 Bystander CPR rates in this study were 22%, and are consistent with other regions,17 however, improvements are needed. Multiple studies have surveyed a variety of groups regarding their willingness to perform bystander CPR, and have identified a host of barriers, among them: composure to act, physical inability to perform bystander CPR, legal liability and transmission of infectious diseases.22 ,23 A successful strategy to improve bystander CPR will incorporate a variety of measures24 enabling timely OHCA identification, encouragement and empowerment of bystanders to act, and provision of effective CPR by them when they do.25 Immediate improvement may be facilitated through the provision of dispatcher CPR instructions which have been recommended,26 and have been shown to improve survival in certain subgroups of patients.27 Bystander CPR is of particular importance in the context of longer Ambulance response times, as seen in this region.

    Rates of attempted resuscitation were higher in this study when compared with the ROC epistry (76.2% vs 58%), while transport rates to an emergency department were similar (56.8% vs 62%, respectively).17 It may therefore be that our paramedics are resuscitating futile cases that were never going to survive, the larger denominator undermining the reported survival. The quality of CPR during transport has been questioned by some authors,28 and transport with ongoing CPR is the exception rather than the rule in some EMS agencies now.15 Fletcher et al describing quality and outcome improvements in Brighton and Hove in England described how they ended the practice of transporting patients to the hospital with ongoing CPR. Instead, crews were taught to take care of the patient where they were found until a pulse was present for at least 10 min, only then did the EMS professionals take the patient to the emergency department. They report that the survival rate for out-of-hospital bystander-witnessed ventricular fibrillation treated by the EMS system in their city improved to about 30% in 2009 and 2010.15 ,29 A clinical-quality cardiac arrest registry facilitates initiatives and interventions such as these in allowing real-time monitoring, governance and support.

    The rural and urban outcomes in this study were similar despite prolonged rural response times. This may be explained by a greater proportion of rural OHCAs being witnessed and receiving bystander CPR. Jennings et al found survival to leave hospital significantly lower in rural Victoria (urban, (7.4%); rural, (1.9%); OR, 4.13; 95% CI 1.09 to 34.91),30 while in Scotland, survival to hospital admission was greater in areas where the median response time was less than 10 min (13.5% vs 8.1%; p<0.05), though the survival to discharge from hospital rate was not significantly different (4.1% vs 3.2%; p=0.42).31 Novel approaches to compensate for prolonged ambulance response times to rural areas have been developed in certain areas; however, demonstrating improved outcomes on low presentation, high mortality events may not be possible.

    This retrospective observational study has some limitations. First, we are unsure of the initial cardiac arrest rhythm in five of our 13 survivors. These may have been either Pulseless Electrical Activity (PEA) or asystole, as they did not receive defibrillation, but we cannot specify survival rates where either PEA or asystole was the initial rhythm, due to missing data. Second, no structured system exists to dispatch prehospital doctors or GPs to the scene, thus limiting the ability to provide ALS to OHCA. Third, we have not linked deaths to autopsy reports; some presumed cardiac OHCAs may include subarachnoid haemorrhages, drug overdoses and abdominal aortic aneurysms whose outcomes may be different from coronary artery occlusion. Fourth, recent evidence suggests that outcomes may differ based on the hospital to which an OHCA victim is delivered.32 This study does not report the inpatient care pathway, such as provision of therapeutic hypothermia or interventional cardiology, which may influence outcome and may differ between the five hospitals to which patients were transported. It may be that designating a cardiac arrest centre for the region may improve outcomes.33

    Specific areas to be addressed in improving OHCA care in Ireland include increasing public recognition of OHCA and warning signs such as cardiac chest pain, introducing safe and reliable call-taking and dispatch with the facility for ongoing audit, improving rates of early bystander CPR and defibrillation, further rollout of the AP program and alerting systems for GPs to maximise the provision of ALS to OHCA victims, and an ongoing OHCA clinical-quality registry as a quality improvement and quality assurance tool.

    Conclusion

    A survival rate of 16.7% in shockable rhythms indicates scope for improvement which would influence the overall survival rate which was found to be 7.4%. The need for better public recognition of OHCA, early bystander CPR and defibrillation, in addition to faster EMS response times for this category of event are challenges seen here and elsewhere. These may in part be addressed by local initiatives. Real-time feedback on performance and quality of the continuum of clinical care through a clinical-quality cardiac arrest registry would monitor and incentivise such initiatives.

    Acknowledgments

    Providers of Out-of-Hospital Cardiac Arrest Care in the Cork region.

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    Footnotes

    • Contributors This is a letter to confirm that all authors have made substantial contributions to all of the following: (1) the conception and design of the study, or acquisition of data, or analysis and interpretation of data; (2) drafting the article or revising it critically for important intellectual content; (3) final approval of the version to be submitted. The manuscript, including related data, figures and tables, has not been published previously and is not under consideration elsewhere. There are no conflicts of interest to declare.

    • Competing interests None.

    • Ethics approval Cork Teaching Hospitals Ethics Committee.

    • Provenance and peer review Not commissioned; externally peer reviewed.