Effects of cardiopulmonary resuscitation with automated external defibrillator training among schoolchildren in Slovenia: A pre- and post-test cohort study

Sudden cardiac arrest is a serious public health concern owing to its high mortality rate, high morbidity, and frequent disability among survivors (1). According to recent data, the rate of bystander cardiopulmonary resuscitation (CPR) in Slovenia is 30%, ranking the country in the bottom third of all European nations (2). The most common reasons for bystander failure to provide CPR to individuals experiencing cardiac arrest include not recognizing cardiac arrest symptoms and lacking CPR knowledge (3), fear of contracting an infectious disease (4), and fear of making a mistake or causing an injury (5). Because early CPR is key to the survival of patients with cardiac arrest, many countries strive to increase the percentage of lay people who would provide CPR with the use of an automated external defibrillator (AED) (6). AEDs provide audio-visual instructions to initiate and guide CPR and can possibly improve CPR quality (7). According to some estimates, at least 15% of the population would have to be trained in CPR to achieve a significant increase in survival rates following cardiac arrest (8), a goal that is impossible to achieve with the existing amount of CPR training offered to adults in Slovenia. It is believed that mandatory CPR training of children in primary schools could help in reaching that goal; in addition to public health campaigns, such training has been proven to increase cardiac arrest survival rates (6, 8). CPR training should be offered in primary schools because, compared with adults, schoolchildren are more motivated to learn, can learn faster and are better able to retain the skills learned (9). In 1961, Norway was the first country in the world to include optional CPR training in the school curricula (10). In Europe, CPR training in primary schools is mandated by law in six countries (Belgium, Denmark, France, Italy, Portugal, and England), whereas others are still in the process of considering this option (11, 12, 13, 14, 15). The joint “Kids save lives” statement on training schoolchildren in CPR worldwide was launched by the European Resuscitation Council and other organizations, and endorsed by the World Health Organization in 2015. This statement recommends two hours of CPR training annually from the age of 12 years in all schools worldwide (8, 11).

Given the importance of early CPR training among children, we investigated pre- and post-training theoretical CPR knowledge in three age groups of schoolchildren to obtain evidence for introducing mandatory CPR training into the primary school curricula in Slovenia.

Compared with the level of CPR knowledge before training, the level of knowledge after training increased to an average score of 11.62 (standard deviation [SD]=2.04) among seventh graders, to 11.44 (SD=2.11) among eighth graders, and to 11.52 (SD=2.00) among ninth graders. The scores improved significantly during the second assessment for all grades (p=0.001 for all three grades of primary school). In the post-training assessment, the level of knowledge was comparable among seventh, eighth, and ninth graders (p=0.693); however, the progress made differed significantly among the three grades (p=0.001). The greatest progress in knowledge was seen among seventh graders, who improved their results by an average of 2.65 points out of a total of 15 points (Table 1).

The distribution of rankings of schoolchildren before and after CPR training is shown in Figure 1. For the entire cohort, the percentage of children who were ranked excellent increased from 5.9% to 35.2%, and the percentage of those who were ranked very good increased from 28.4% to 38.2%. Moreover, fewer children were ranked in the categories good, satisfactory, and unsatisfactory after CPR training.

Figure 1

Table 2 shows the knowledge rankings according to different grades. A statistically significant improvement in knowledge rankings was noted among children in all three primary school grades included in the study (p<0.005 for all). After training, the scores obtained by seventh graders were comparable to those of the eighth and ninth graders. Seventh graders comprised most respondents who were categorized as having very good or excellent CPR knowledge after training (38.9% and 36.8%, respectively).

The proportion of explained variance of the final score obtained on the pre-training test was 4.6% (R²=0.046), and this model was thus acceptable and significant (F=6.089, p<0.001). Children with a higher mean age (β=0.128, p=0.001), girls (β=−0.109, p=0.006), children with a higher BMI (β=0.081, p=0.037), and those who had previously participated in CPR training (β=0.090, p=0.024) showed greater knowledge levels. In the predictive post-training model, few independent variables were suitable for inclusion. Although the model was statistically significant (F=9.036; p=0.004), it explained 4.4% of the knowledge level variance (R²=0.044), and girls had greater knowledge after training than boys (β=−0.119, p=0.002). Both before and after CPR training, girls’ final test scores were up to 0.7 points higher than those of boys (B=−0.447 and B=−0.704, respectively) (Table 3).

In this study, we examined the impact of a single two-hour theoretical and practical CPR training on the level of CPR knowledge, assessed one to two months after training, in a large sample of Slovenian schoolchildren enrolled in the final three grades of primary school (aged 12–15 years). The main finding of this study is that the implementation of CPR training was most effective at the age of 12.5 years (seventh graders). Greater CPR knowledge was associated with previous training, and thus continuous CPR education should be introduced into school curricula.

CPR education among schoolchildren increases the rate of bystander CPR and improves survival after cardiac arrest. Convincing data in this regard is reported from Denmark, where mandatory CPR education was implemented in 2005 (6), and from the United States, where the American Heart Association advocated compulsory CPR training in all American schools nine years ago (24). The optimal age proposed by the European Resuscitation Council to begin CPR training is 12 years old (8). The American Heart Association recommends that CPR be taught from as early as age 9 years, although at that age schoolchildren can only learn certain aspects of CPR (24). It has been shown that schoolchildren aged 7 to 10 years are sufficiently able to recognize the signs of cardiac arrest and understand the importance of CPR and the use of AEDs (25, 26, 27). Owing to having a lower BMI, the depth of chest compressions provided by children in this age group is insufficient; however, they are as successful as their older peers in the frequency of chest compressions provided and the correct CPR sequence (25, 28). Some authors have found that younger schoolchildren are as successful as their older peers in providing chest compressions and in attaining adequate theoretical CPR knowledge, on the condition that they receive continuous CPR training (19, 27). Nevertheless, data regarding the most appropriate age to start teaching different components of CPR are inconsistent because most evidence mainly focuses on the physical ability to perform practical CPR skills (25, 26, 29). In general, our study revealed a moderate level of pre-training theoretical knowledge in cardiac arrest and CPR principles (mean score 9.46±2.08, maximum score 15). Baseline theoretical CPR knowledge prior to training, using a 15-item questionnaire, was greatest in ninth graders (average age 14.5 years) and lowest in seventh graders (average age 12.5 years); similar findings have been reported in most other studies conducted among schoolchildren (19, 25).

At 1 to 2 months after CPR training, a significant improvement in the level of theoretical knowledge remained among students in all three observed grades. Surprisingly, children in all grades had a comparable level of knowledge (mean score 11.53±2.05, maximum score 15). After CPR training, most participating schoolchildren were categorized as having very good or excellent knowledge, which is in sharp contrast to the pre-training findings where most children were categorized as having good, satisfactory, or unsatisfactory knowledge. Although the effect of CPR training with the use of an AED on theoretical knowledge among the participants is evident, one would expect the differences in knowledge established before training between different grades to also be reflected after training. The number of correct answers in the written test two months after training increased by 17.5%, 13%, and 9.8% among the seventh, eighth, and ninth graders, respectively. This means that the effect of CPR training on improvement in CPR knowledge was inversely proportional to the age of schoolchildren; the observed improvement in theoretical knowledge scores was highest among seventh graders, as supported using exploratory statistical methods rather than explanatory methods. We can thus conclude that younger schoolchildren are more influenced by theoretical content related to resuscitation and the implementation of CPR with an AED. In contrast, some authors have found that schoolchildren aged over 13 years were more successful in solving theoretical tests after training than their younger peers (19, 25, 26). Although our study showed that the level of knowledge after CPR training was comparable for different grades (seventh graders did not achieve higher scores than eighth and ninth graders), it is nevertheless advisable to begin CPR training in the use of an AED among younger children, as suggested in previous research (20, 24, 27, 30). This is because younger schoolchildren are better able to learn practical CPR interventions than their older peers (26), and also because early training reduces anxiety about making mistakes and considerably increases participants’ willingness to help (19). In general, continuous training helps with retaining the same level of knowledge, although a six-year longitudinal analysis carried out in Germany showed that resuscitation skills were retained even when training was interrupted for three years (26). The correlation between previous CPR training with the use of an AED and level of knowledge in our study suggests that CPR training should be provided continuously, preferably as a brief annual refresher training. Strong interaction effects of training frequency were seen in both CPR knowledge level and chest compression depth (19). CPR training in the use of an AED must be adapted to schoolchildren’s age and gender (31, 32), and modern teaching approaches, such as self-instruction kits and computer-based learning, should be used. Preferably, CPR training should be conducted by school nurses whenever possible, or by schoolteachers with experience of teaching CPR (27). The German Resuscitation Council has proposed an exemplary model curriculum for primary schools based on children’s cognitive and psychomotor development, in which the training content and goals are arbitrarily divided into three age groups (8–10, 11–14, and 15–18 years) (31). Although these recommendations were issued eight years ago, Germany had not yet adopted CPR legislation at the time of the present study (11).

A higher level of CPR knowledge prior to CPR training was noted in older schoolchildren, those with a higher BMI, girls, those who had previously attended CPR training, and schoolchildren whose mothers had higher educational achievement. Girls had higher levels of knowledge than boys both before and after CPR training. Better motivation and attitudes toward CPR and better theoretical CPR performance in girls compared with boys were demonstrated in a recent review, suggesting that sex-related aspects need to be addressed in CPR training program in schools (33). The correlation between higher maternal educational achievement and higher levels of CPR knowledge among schoolchildren might suggest that children whose mothers have a higher level of education tend to have a more positive attitude toward education, place a higher value on knowledge, have higher expectations of themselves, greater awareness about the importance of skills in resuscitation, and feel socially responsible to conduct CPR. However, these assumptions were not investigated in our study, and should be further explored.

This study demonstrated a marked improvement in the post-training levels of theoretical CPR knowledge in a large cohort of schoolchildren aged 12–15 years. Because the greatest increase in knowledge was observed among seventh graders, CPR training should be introduced to children at a mean age of 12.5 years (i.e., seventh graders). Previous research has shown that bystanders fail to recognize cardiac arrest and to provide assistance owing to a lack of knowledge and fear of performing resuscitation procedures. In addition to increased knowledge, early and compulsory CPR training during childhood can induce long-term behavioural changes and reduce anxiety around making mistakes, which could translate into better outcomes for survivors of cardiac arrest.