Out-of-hospital cardiac arrest surveillance in Canada: a survey of national resources

EM Advances

CJEM 2010;12(2):119-127

Abstract

Résumé

Introduction

There are approximately 40 000 victims of cardiac arrest each year in Canada.1 Cardiac arrest is defined as "the cessation of cardiac mechanical activity as con firmed by the absence of signs of circulation."2 It is invariably fatal if not treated within minutes. Forty per cent of all cardiac arrest deaths occur suddenly and con stitute the first manifestation of heart disease for some people.3 Approximately 70% of all cardiac arrests occur in the prehospital setting.4 Among these out of hospital cardiac arrests (OOHCAs), 85% occur in the victim's residence.5 Currently in Canada, the overall survival rate to hospital discharge rarely exceeds 5%.5

Current prehospital treatment strategies for OOHCA are based on relatively weak data, often from animal investigations or uncontrolled human studies. In 2000, the Post resuscitative and Initial Utility in Life Saving Efforts (PULSE) international workshop identified numerous knowledge gaps in the care for victims of cardiac arrest.6,7 Among these gaps, PULSE identified the need to develop regional, national and interna tional cardiac arrest registries. In 2004, the Interna tional Liaison Committee on Resuscitation (ILCOR), in collaboration with 7 international resuscitation councils, published a revised and simplified Utstein template to facilitate the collection of information on cardiac arrest and cardiopulmonary resuscitation for resuscitation registries.2 The same year, the Canadian Cardiovascular Outcomes Research Team collaborated with researchers in emergency medicine to publish an article entitled "Cardiac arrest care and emergency medical services in Canada."5 This project highlighted regional variations in survival outcomes, and an overall paucity of comprehensive information on OOHCA in Canada.

To test new interventions and ultimately improve overall survival for OOHCA victims, we need access to good quality prehospital and in hospital data that are captured and recorded in a systematic and consistent fashion. There currently is no uniform program in place to collect information on OOHCA in Canada. The general objective of this study was to explore the challenges of establishing an OOHCA surveillance pro gram in Canada. More specifically, we attempted to determine the organizational structure of the delivery of emergency medical services (EMS) in Canada, describe the OOHCA data collection infrastructure in each province and determine which OOHCA variables are being collected.

Methods

Study design

We conducted a national survey to obtain information on the current status of OOHCA data collection across Canada. Because we did not collect information on human subjects, this survey did not require review by our institution's ethics review board.

Survey instrument

We developed the survey instrument after reviewing the literature on cardiac arrest registries, and incorporated the findings from a consensus publication by ILCOR.2 This ILCOR publication represents a consensus among cardiac arrest researchers from 7 international resuscita tion councils, listing a set of core variables that should be routinely collected for OOHCA and cardiopulmonary resuscitation as part of a resuscitation registry. We included these core variables in our survey in an effort to determine whether these patient and system characteris tics variables are captured across Canada. A panel of experts from the Ottawa Hospital Research Institute, the Heart and Stroke Foundation of Canada, the Public Health Agency of Canada, the Canadian Institute for Health Information and Statistics Canada reviewed the survey instrument for content and face validity.

In order to establish our distribution list, we searched the Web and obtained contact information for each provincial ministry of health. We subsequently con tacted several representatives from each provincial min istry of health by telephone and/or by electronic mail to determine who was responsible for prehospital emer gency services at the ministry, to obtain a list and con tact information for each responsible regional health authority in the province, and to determine whether a provincial OOHCA registry already existed. We defined "health authority" as any administrative entity responsible for the delivery of prehospital care in a well defined geographical area. In addition, we con tacted several cardiac arrest researchers, EMS program managers and EMS medical directors in each province to verify the completeness of our distribution list, which can be found in Appendix 1.

We distributed the survey in both official languages using a modified Dillman approach to all identified EMS health authorities in Canada (territories excepted). Participants were asked to provide informa tion on their EMS organization, data collection infra structure and ability to collect information on specific patient and system characteristics.

Data management and analysis

We entered data into an Access database (Microsoft Corp.), and randomly selected 25% of surveys to verify for data entry errors or omissions. We further ensured data quality using visual database inspection and verifi cation of expected data ranges.

Because a respondent could represent a small regional health authority or an entire province, we weighted each survey response by the population of the catch ment area represented by the health authority. We based population weights on Jul. 1, 2004, demographic statistics available from Statistics Canada.8 Weighting procedures have been well described for population based surveys.9-12 They provide more accurate estimates of the effective response rate, and can account for inequities in sampling and probabilities of selective representativeness. We performed a series of simple descriptive analyses using SPSS 11.0 (SPSS Inc.) and Excel (Microsoft Corp.).

Results

We distributed the survey in March 2005 to each of the 82 independent health authorities identified across Canada; we sent 67 (84%) electronically and the rest by regular mail. We received 60 completed surveys, repre senting a 73% response rate. The responding health authorities' catchment areas represented 80% of the Canadian population (weighted response rate). Charac teristics of the survey respondents and their population weights are presented in Tables 1 and 2.

The organizational structure of EMS varies across the country. In British Columbia, Nova Scotia and Prince Edward Island, EMS leadership comes directly from a single regulatory provincial body. In other regions (rep resenting 61% of the Canadian population), EMS is coordinated and administered by the regional health authorities, under the regulatory supervision of a provincial body. In few regions (representing 17% of the Canadian population), the regional health authority operates independently from a provincial regulatory body. In addition to land ambulances, most regions (89%) use a multiple tier response system for OOHCA emergencies consisting of firefighters (90%), police officers (49%) and first responders (40%).

Information on data collection infrastructure is pre sented in Table 3. Although several health authorities are moving toward electronic prehospital data capture, most continue to use paper charts for patient care reports. These patient care reports are usually standard within a given province, but they vary in content among provinces. Most regional health authorities maintain an OOHCA database. Two provinces, British Columbia and Nova Scotia, already maintain a provincial OOHCA registry. Data entered into these databases come from the paramedic's patient care report, and, in some cases, from the 911 dispatch centres. A minority of respondents reported the ability to link with in hospital outcome databases. The case identifiers most often used for data linkage are a run number assigned by the EMS system, followed by the victim's name. Information is most commonly entered manually into a database, and most respondents report using the Utstein template and data definitions for data entry. Data quality are insured using rudimentary methods such as simple visual inspection in the majority of cases. Among those enter ing OOHCA data in a database, only 70% mentioned being unable to pool their information with another region. More than confidentiality issues, respondents believe it is the lack of available resources causing the inability to pool their information. When data from more than one region are pooled, it is performed manu ally most of the time.

Information on patient and system characteristics col lected by the regional health authorities surveyed is pre sented in Table 4. Although most respondents reported using the Utstein template for OOHCA data collection, we observed great variation in what information is col lected and entered into OOHCA databases across the country. For example, only 80% of respondents reported being able to specify whether an OOHCA case was of cardiac etiology in their database. Demographic information on the victim including age, date of birth, sex and location when cardiac arrest occurred was cap tured in the majority of databases. However, informa tion pertaining to events occurring before paramedics' arrival was more variably captured; these variables included estimated time of collapse, estimated time car diopulmonary resuscitation (CPR) was initiated, differ entiating between CPR provided by citizen, fire or police, and the quality of CPR provided. In addition, there is great variability in the ability to collect informa tion following prehospital interventions, including survival to the emergency department, survival to hospital discharge, neurologic status at discharge and time of death. Although 50% of respondents reported the ability to collect information on survival to hospital discharge, only a minority of them reported the ability to link with in hospital outcome databases electronically.

Discussion

There currently is no national OOHCA surveillance program in Canada. The goal of this study was to explore the challenges of establishing such a program. The first step in establishing whether this is possible or not is to determine how and what information is being collected. We accomplished this by administering a sur vey to regional health authorities responsible for the delivery of EMS Services in the 10 provinces of Canada. The response rate was high, representing regions served by a large proportion of the Canadian population.

The survey results indicate that systems are in place that could be upgraded for the purpose of a national OOHCA surveillance program. When we reviewed the literature on this topic, we also identified a number of ongoing provincial initiatives that could potentially facili tate the implementation of an OOHCA surveillance pro gram in Canada. For example, the Western Electronic Health Record Regional Collaborative has been created to accelerate the delivery of electronic health records in British Columbia, Alberta, Saskatchewan and Manitoba.

The Health Information Solutions Centre is working with 5 of Saskatchewan's midsized regions to implement common, shared health care computer systems through a project called Integrated Clinical Systems.13 The Western Health Information Collaboration is a collaboration among the western provinces and territories to meet their health information needs.14 One of their initiatives is called the Ambulance Patient Care Information Sys tem. In Ontario, prehospital and in hospital data on car diac arrests in 20 cities have been routinely collected in a database since 1991 for the Ontario Prehospital Advanced Life Support (OPALS) study.15 In 2005, the Resuscitation Outcomes Consortium (ROC) was estab lished to facilitate clinical research on OOHCA and major trauma victims.16 British Columbia, Toronto and many of the original OPALS communities participate in this initia tive, and share a common OOHCA epidemiologic reg istry, also referred to as "epistry."17

Although there are many ongoing initiatives that could facilitate the implementation of a national OOHCA surveillance program, the survey results highlight a number of important challenges that would need to be addressed and overcome. First, some of the core Utstein data elements are being captured only sporadically. It is also essential to have access to in hospital survival statistics in order to evaluate the impact of prehospital interventions; we have discovered that only a minority of health authorities have access to such information. Second, we have noticed some vari ability in the way some health authorities interpret the Utstein data element definitions; common definitions would need to be adopted for the entire registry. Third, although the lack of resources appeared to be the major factor limiting the ability of respondents to share data among themselves, confidentiality issues may also represent a potential barrier to the implemen tation of a national OOHCA surveillance program. In the case of British Columbia, participation in a national OOHCA surveillance program could lead to contrac tual breaches with sponsor manufacturers such as Medtronic, Laritol and Space Lab. Finally, although the ROC and a Canadian OOHCA surveillance pro gram have much in common in terms of variable selec tion and definitions, each data registry initiative differs in its potential ability to adequately represent a broad range of urban and rural communities in Canada. Moreover, it is possible both initiatives will be in com petition for the same sources of funding.

It is important to acknowledge the potential limitations of this survey. First, we were unable to ascertain the con struct validity of the survey tool, and could not produce any pilot data owing to the tight timelines imposed on the project. Second, despite our success in collecting information from a representative sample of the country, we were unable to obtain a response rate higher than 60% for Alberta, Saskatchewan and New Brunswick. This being said, we were able to collect information from most large urban communities in those 3 provinces. Third, although respondents made diligent efforts to answer the questions in our survey to the best of their understanding, our analysis remains dependent on the accuracy of the information that was provided to us. Finally, the unit of analysis used was "the regional health authority responsible for OOHCA collection." In some cases, this meant a region very sparsely populated; for others, this may have meant a whole province. For this reason, we decided to weigh each survey response by their respective catchment area; these adjusted rates, although somewhat artificial, can help us draw more appropriate conclusions. We made no assumptions regarding nonresponding health authorities.

In conclusion, the results of this survey demonstrate the possibility of collecting OOHCA data and accessing in hospital survival outcomes. Future efforts should be concentrated in establishing common data definitions according to a common template, ensuring uniform data quality, establishing and maintaining linkages to in hospital survival outcomes, addressing potential confi dentiality issues in each province, determining ware housing location, finding financial resources for the project, and exploring collaborative efforts with the ROC and other potential provincial partners.