Cardiac arrest refers to the sudden cessation of cardiac mechanical activity as confirmed by the absence of signs of circulation 1. The victim collapses when the cardiac mechanical activity becomes too limited to provide adequate blood flow and oxygen to the brain and muscles. The victim is perceived to be lifeless if no vital signs are detectable (responsiveness, pulse, respiration). Electrical cardiac activity (ventricular fibrillation [VF], ventricular tachycardia [VT], or pulseless electrical activity [PEA]) seen on a cardiac monitor may become the only sign of vital activity. In the absence of cardiopulmonary resuscitation (CPR) and/or electrical defibrillation, such electrical cardiac activity is followed by asystole and then by death in a matter of minutes.

Cardiac arrest remains the leading cause of mortality in North America. The incidence of out-of-hospital cardiac arrest in Canada is estimated to be 55 per 100,000 of population 2, resulting in more than 17,875 deaths annually. Coronary artery disease is the most frequent condition leading to cardiac arrest 3. More than 40% of all deaths from heart disease occur suddenly, and often constitute the victim's first manifestation of heart disease 4. Sixty-five percent of all cardiac arrests occur outside the hospital setting 5, where the overall rate of survival to hospital discharge rarely exceeds 5% 2. Survivors have a quality of life (Health Utilities Index Mark 3) similar to the general population 6. Most commonly, cardiac arrest victims are men in their sixties. Canadian cardiac arrest victims collapse in their own home 85% of the time and 50% are witnessed by a family member or bystander 2. However, bystander CPR rates remain low in Canada, and rarely exceed 15% of all cases in Ontario 2.

The American Heart Association "Chain of Survival" illustrates important concepts in the community response to out-of-hospital cardiac arrest 7. The chain metaphor implies that cardiac arrest care is only as strong as its weakest link among the four links in the chain: 1) Early access: When dialling 9-1-1, a caller is put in communication with personnel that will appropriately dispatch police, fire, emergency medical services (EMS), or all three. In the case of a medical emergency, the call will rapidly be transferred to a medical dispatch centre. Dispatch Officers collect information on the nature of the medical emergency and dispatch the appropriate EMS unit(s), often as more information is being collected. 2) Early CPR: CPR can be defined as a succession of lung insufflations and chest compressions performed by a rescuer with the intention of restoring spontaneous circulation. Although police, fire, and EMS paramedics have all been trained to perform CPR in cases of cardiac arrest, it is what occurs during the first minutes before their arrival that is most crucial to the victim. A victim is almost four times more likely to survive a cardiac arrest event when receiving citizen bystander CPR before emergency personnel arrives [OR 3.7 (95% CI 2.5–5.4)] 8. 3) Early defibrillation: Defibrillation occurs when myocardial cells in a chaotic or abnormal electrical rhythm, VF or VT, are depolarized at the same time by the delivery of an electrical current. This results in the re-establishment of a rhythmic and organized heart beat. Defibrillation can only occur when the heart exhibits disorganized electrical activity and is never successful in the case of asystole or PEA. 4) Early Advanced Care: Advanced cardiac life support care is defined by the use of definitive airway management such as endotracheal intubation, intravenous access and administration of drugs. Such drugs serve the purpose of increasing the coronary perfusion pressure by increasing peripheral vascular resistance (Epinephrine, Vasopressin), or to promote arrhythmia termination either alone by acting on myocardial cell electric action potential and/or by facilitating defibrillation (Lidocaine, Procainamide, Amiodarone). This being said, early advanced care failed to improve survival to hospital discharge in the largest prospective prehospital study conducted to date 8.

Data from Seattle indicates that a survival rate of 30% can be achieved for witnessed VF cardiac arrest victims receiving bystander CPR 9. Other communities such as Akita and Otsu, Japan report overall survival rates from cardiac arrest of 15% and 9%, respectively, in association with bystander CPR rates of 49% and 29% 10. In comparison, citizen bystander CPR and overall survival rates are rather modest in most Canadian provinces, rarely exceeding 15% and 5% respectively 2.

Various attempts have been made to improve bystander CPR rates in the past. Two very popular and contrasting approaches are mass CPR training events and targeted CPR training of family members of patients suffering from cardiovascular disease. The objective of the mass CPR training is to teach as many CPR providers as possible from the general population in a group setting. Although mass CPR training events can reach groups of a few hundred to thousands of participants at a time 11121314, these events usually attract young participants unlikely to witness cardiac arrest. In addition, they are not cost-effective15 and their effect on survival has not been demonstrated. Targeting the population at large may not achieve the desired goal of increasing bystander CPR rates 1617.

The second approach, targeted CPR training, involves spouses and other family members of cardiac arrest victims, the people most likely to witness the event 181920. Many authors have suggested targeting family members of patients with known cardiovascular disease for CPR training 212223242526272829303132. As few as 9% of this target group have generally received CPR training, while the highest rate is found in Detroit at 47.4% 2033343536. Although one study associated advancing age with failing to succeed in CPR training 37, other publications show a high success rate in the older population group 383940. While some authors suggest the addition of counselling to deal with the extra responsibility and stress associated with being a potential CPR provider 4142, CPR training was shown to decrease anxiety, and increase emotional adjustment in family members of cardiac arrest survivors 434445. Since 40% of cardiac arrest victims never had any documented cardiovascular disease preceding the event 4, targeting only family members of patients with known cardiovascular disease may not achieve the desired goal. Instead, we should find ways to target the whole population at risk, namely the male and female population aged 55 and older.

Irrespective of the teaching method, retention of CPR knowledge and skills is poor 464748. The Heart and Stroke Foundation of Canada currently recommends yearly retraining 49. There is a large amount of literature demonstrating a significant decrease in CPR knowledge and skills after one year 50515253545556575859606162. Trainees may go back to pre-training skill levels as early as six months after their CPR class 6364656667. Some evidence exists that re-training may be protective against a decline in CPR skills 68.

Authors have asked many people why they were not interested in taking a CPR class. A common response from lay persons is that it simply never occurred to them that CPR training was something they should be doing. Interest in CPR training appears to decrease with advancing age 6970717273. When a group of elders were asked why they had not sought CPR training in the past, most gave no specific reason, or mentioned the inconvenience of having to leave the house, bad health, or cost 7475. Some respondents did not understand why they should perform CPR when they can call 9-1-1 76. Other common reasons for not seeking CPR training were lack of time or interest, inability to find a course, physical limitations, fear of contracting HIV, or fear of being sued despite the absence of any successful lawsuit for having provided CPR 7778. To the contrary, the notion of negligence and failure to provide support could theoretically have legal consequences 79. There is a lack of consistency among what various studies have found, and none of them clearly demonstrated which factors were most susceptible to influence someone's decision to seek CPR training.

It is also important to address the fear of contracting an infectious disease. Historically, tuberculosis and polio were major concerns on the minds of potential rescuers 80. In our time, HIV and hepatitis B have replaced those diseases 8081. Two surveys published in the late eighties reported that up to 50% of CPR students and instructors alike believed HIV to be transmissible despite standard precautions or simply from giving mouth-to-mouth to a manikin 8283. In another survey published during the same period, 90% of homosexuals knew that HIV could not be transmitted from mouth-to-mouth ventilations 84. No case of HIV, hepatitis B, hepatitis C, or Creutzfeldt-Jakob disease has ever been reported as a result of providing basic CPR to a victim or a manikin 8586. There are only three documented cases of horizontal transmission of HIV to health care professionals and they all involved a significant amount of blood and the absence of basic precautions 85. In a time where people are better educated about the transmission of communicable diseases, we need to re-examine what effect the fear of HIV has on bystander CPR.

Besides fear of disease transmission, there exist other deterrents to bystander CPR. Mouth-to-mouth ventilation is an intimate act that may influence the decision of potential rescuers to perform CPR 8788. Willingness to perform CPR appears directly related to the closeness of the relationship with the victim 1325347589909192. In a survey conducted in 1995, 68% mentioned they would perform only chest compressions on a stranger 93. Other conditions such as vomit, dentures, blood, body odour, and alcohol smell may be unexpected, and have been associated with reluctance to provide CPR to a cardiac arrest victim 94959697. Nobody knows what impact these conditions have on bystander CPR rates.

CPR certification is associated with increased confidence in one's ability to provide care, which in turn is associated with an increased helping behaviour 27339899100101. But CPR training is still not an assurance of action when the time comes for the rescuer to apply what he or she has learned 102. Social scientists have studied the effects of ambiguity and the presence of other bystanders on helping behaviour. The more obvious it is that actions are required in a specific situation, the more likely it is that someone will help 103104105106. It has been suggested that people are often unable to make the decision to help rather than choosing not to help 104. Furthermore, it has been demonstrated that overall helping behaviour decreases with an increasing number of bystanders, a phenomenon known as diffusion of responsibility 106107108109110. Although the likelihood of finding someone with CPR training in a crowd increases, the helping behaviour of that rescuer will be reduced by the presence of the other bystanders. Simple and complex behavioural methods have been postulated to address those issues, most of them involving one form or the other of behavioural or cognitive approaches to teaching helping behaviour, but none specifically during CPR classes 111112113. Once again, we do not fully understand what truly motivates an individual to perform CPR or not when it is necessary to do so.

While it remains unclear from previous research if situation-specific factors such as the ones mentioned previously affect the likelihood of CPR-related behaviours, it may also be that general constructs known to affect other health-related behaviours are also relevant. Examination of CPR training and performance behaviours have never been studied in the context of these more general theories, despite their utility in explaining a wide variety of health behaviours 114115116117118. For example, the theory of planned behaviour (TPB) proposes that the strength of an individual's intention (or motivation) to engage in a behaviour, and the degree of control they feel they have over that behaviour (perceived behavioural control) are the proximal determinants of engaging in it 119. The TPB also proposes that intention strength is determined by three variables: attitudes towards the behaviour (a product of beliefs about its consequences and evaluations of those consequences), subjective norms (a product of perceptions of the views of other individuals or groups about the behaviour, and the strength of the individual's desire to gain approval of these groups) and perceived behavioural control (a function of beliefs about factors likely to facilitate or inhibit the behaviour – these might include organizational constraints and patient preferences). The TPB has been shown to predict a range of individual health related behaviours with some success 120121 (e.g. recent meta-analyses have suggested that the TPB can account for around 20% of the variance in health behaviour 122123124). To our knowledge, the TPB has never been utilized to study bystander's motivations with regard to CPR training and performance. However, early studies suggest that it is a useful, systematic tool to identify barriers to and facilitators of change and hence appropriate forms of intervention 122123124125126127128.

CPR is a crucial yet weak link of the Chain of Survival for out-of-hospital cardiac arrest. We sought to understand what is known about the determinants of bystander CPR and factors associated with successful CPR training by conducting a systematic review of the available literature 129. Eleven electronic databases, one trial registry, and nine scientific web sites were searched. In addition, hand searches were performed and six content experts were contacted. All communications pertaining to WHO should learn CPR, WHAT should be taught, WHEN to repeat training, WHERE to give CPR instructions, and WHY people lack the motivation to learn and perform CPR were reviewed with restriction. Publications were grouped by category and recommendations were developed using a standardized classification system based on level of evidence.

A total of 252 articles were included out of 2,409 located. Differences in their study design precluded a meta-analysis. Twenty-two recommendations were classified. Recommendations with the highest scores (A, I-2) were: 1) Dispatch-assisted CPR instructions; 2) Teaching CPR to family members of cardiac patients; 3) Braslow's self-training video; 4) Maximizing time spent using manikins; and 5) Teaching concepts of ambiguity and diffusion of responsibility. Other examples include: Mass training events (C, II-3), pulse taking by laymen (D, I-2), and CPR using chest compressions alone (E, I-2).

This exercise resulted in the evaluation and classification of the potential impact of interventions designed to improve bystander CPR rates. These results will help identify common barriers and facilitators to CPR training and CPR performance for the purpose of the current project, more specifically for the purpose of including theoretical constructs represented in the literature.

A multi-phase approach will be taken to develop, pilot-test, and administer a telephone survey examining the determinants of CPR training and performance among a population aged 55 or older. In the first phase, data will be used from a recently completed systematic review of the literature 129 to inform the development of a semi-structured interview guide designed to identify barriers and facilitators to a) obtaining CPR training, and b) actually performing CPR, among our target population. Interviews of people aged 55 and older will be carried out until information saturation is achieved; we estimate no more than 20 interviews will be necessary. In the second phase, relevant barriers/facilitators to the two CPR-related behaviours from the interviews will inform development of a pilot telephone survey using the theoretical framework provided by the Theory of Planned Behaviour. In the third phase, a telephone survey will be conducted on individuals over the age of 55 to identify which combinations of barriers, facilitators, and theoretical constructs best predict intention to receive CPR training and/or to perform CPR on a cardiac arrest victim.

The primary hypotheses of the third phase of the project (Survey Phase) will involve examining whether constructs comprising the Theory of Planned Behaviour are significantly related to our two primary outcomes. Specifically:

Hypothesis 1: Attitudes, subjective norms, and perceived behavioural control will be significant predictors of intention to engage in CPR training, and

Hypothesis 2: Attitudes, subjective norms, and perceived behavioural control will be significant predictors of intention to engage in intention to perform CPR in appropriate circumstances.

Analysis of the survey data will first involve descriptive statistics describing the most commonly cited barriers/facilitators to our two target behaviors. Analysis of Hypothesis 1 and 2 will be carried out by multiple regression. For each of the two target behaviours (intention to engage in CPR training, intention to perform CPR), a blocked multiple regression will test the strength of relationship of these outcomes with the constructs predicted by the Theory of Planned Behaviour; i.e. the constructs of attitude, subjective norms, and behavioural control will be added into the model as a block, and any additional constructs suggested by the Interview Phase added to the model to see if it contributes to the model over and above the factors discussed in the Theory of Planned Behaviour.

In addition to standard regression modelling, we will also produce a structural equation model of our data. Structural equation modelling (SEM) allows the researcher to model not only direct relationships between constructs and outcomes (e.g. is perceived behavioural control related to actual behaviour?), but also indirect relationships through intervening constructs (e.g. is the effect of perceived behavioural control on intention mediated by other constructs?). Because the constructs in the structural model are determined theoretically rather than statistically, this technique is useful for testing the validity of whole theories within a single analysis. Furthermore, SEM does not assume perfect measurement of the constructs, as does regression, but rather explicitly measures and excludes error in the measurement variables from the definition of the constructs.

Power calculations for multiple regression analysis depend on the number of cases per predictor variable. A minimum sample size of 50 + 8 m, where m is the number of predictor variables, is recommended for testing the multiple correlation, and 100 + 8 m for testing individual predictors 140141. The two behaviours under study will be "seeking CPR training and providing CPR to a cardiac arrest victim". The survey will be organized using the theoretical constructs of the Theory of Planned Behaviour which measure: behavioural intentions, attitudes, subjective norms, and perceived behavioural control. Assessments for each of the four theoretical constructs for both behaviours under study will include direct and indirect belief-based measures; each measure will use a minimum of three items on a 7-point Likert scale. Our survey will require a minimum of 146 respondents (assuming three confounders per theoretical construct). We will over sample to handle incomplete data, and target 200 participants.

This study has been approved by the Research Ethics Board of the Ottawa Hospital (protocol # 2007751-01H).