Out-of-hospital cardiac arrest (OHCA) is witnessed by relatives, friends or other people in 70% of cases. In most instances, bystander cardiopulmonary resuscitation (CPR) attempts take place in the home, but CPR is only attempted before the arrival of medical emergency teams in less than 20% of cases,1 when early CPR is a key determinant of survival and neurologic outcome.2 The main strategy to increase the frequency of bystander CPR is training in basic life support (BLS), and in this regard, school-based training of students may be one of the most effective approaches.1,3

In Spain, there have been several official initiatives and projects to provide BLS training in the school setting,4–6 but there is no evidence yet on its actual impact on bystander initiation of BLS and victim survival. On the other hand, several studies in recent years have analysed the methodology of BLS training in children, with educational strategies varying significantly in terms of the duration of training, the methods used, the instructors and the minimum age for training.7

The Kids Save Lives initiative promoted by the European Resuscitation Council (ERC) with the support of the World Health Organization recommends 2 hours of school-based CPR training a year starting from age 12 years.3 However, it may not be necessary to wait until this age to start teaching first aid and BLS skills to children, as children as young as 6 years of age can learn the chain of survival8 and even how to use a semi-automatic defibrillator.9 In addition, while children under 12 years may not be able to deliver quality chest compressions (possibly on account of anthropometric factors),10 they are capable of delivering vigorous compressions and learn theoretical concepts.

The Adestrando Nenos e Xóvenes a Salvar Vidas project (Teaching children and youth to save lives, ANXOS) addresses the main practical uncertainties that have emerged in relation to school-based BLS training of children and youth. In this context, the aim of our study was to assess the acquisition of BLS theoretical knowledge and skills in students aged less than 13 years through a brief training delivered by their physical education instructors.

The initial sample consisted of 658 students, of who we excluded 42 (6.4%) due to incomplete data and 49 (7.4%) due to lack of signed informed consent at the start of the study, so the final sample included 567 students (48.0% female). The distribution by school year was: 32.1% in year 3 of primary education (PE), 31.6% in year 5 of PE, and 36.3% in year 1 of compulsory secondary education (known in Spain as ESO).

Basic life support sequence

Fig. 1 and supplemental file 3 in Appendix B present the data concerning the performance of the BLS sequence after the training. At least 50% of the students were able to perform all the steps in the BLS sequence in each school year. The steps the students performed less frequently (< 70%) were “securing the scene” and “checking for a response” (students in year 3 of PE) and “opening the airway” (students in year 3 of EP and year 1 of ESO). More than 80% of students performed the “look-listen-feel assessment of breathing”, “alerting medical emergency services” and “initiation of chest compressions” steps.

Figure 1.

Percentage of participants that performed each step of the basic life support chain sequence post training. Data disaggregated by school year.

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When we analysed the percentage of students that performed the full sequence by school year, we found that a higher proportion of students in year 5 of PE could perform the full sequence compared to year 3 of PE or year 1 of ESO (year 3 of PE: 16.5%; year 5 of PE: 54.4%; year 1 of ESO: 28.5%; P = .030). In the subset of students that performed the full sequence, we did not find significant differences based on school year in the seconds elapsed from the start of the simulation to initiation of chest compressions (year 3 of PE: median, 52.2 [IQR, 43.3-58.7]; year 5 of PE: median, 47 [IQR, 42.5-55.3]; year 1 of ESO: median, 40.7 [IQR 40.3-56.4]; P = .577).

Quality of CPR

Fig. 2 presents the results on the parameters used to assess the overall quality of CPR by school year, with additional results presented in supplemental file 4 in Appendix B.

Figure 2.

Overall quality of resuscitation and each compression-related variable. Data disaggregated by school year.

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The chest compression fraction, mean depth of compressions and percentage of compressions with correct depth increased with the school year (P < .001). We also found significant linear associations between with CPR quality parameters and anthropometric variables (Table 1).

Table 1.

Linear relationship between cardiopulmonary resuscitation variables and anthropometric variables.

	Weight	Height	BMI
	r	r	r
	P	P	P
Overall quality of resuscitation	0.572	0.518	0.405
	< .001	< .001	< .001
Mean depth of compressions	0.636	0.618	0.450
	< .001	< .001	< .001
Percentage of compressions with adequate recoil	−0.237	−0.167	−0.228
	< .001	< .001	< .001
Percentage of compressions with adequate depth	0.470	0.398	0.334
	< .001	< .001	< .001
Percentage of compressions at adequate rate	0.111	0.129	–
	0.008	0.002	–

BMI, body mass index.

Fig. 3 presents the results regarding the depth of compressions (mm) and mean rate of compressions (per minute). It shows a target area, marked in red, that includes the recommended values,13 and a blue area defined by arbitrary deviation thresholds of ± 10 compressions per minute and ±5 mm of depth. When it came to depth, the target of 50 mm was only achieved by 3.4% of participants in year 1 of ESO (P = .002) compared to none in years 3 and 5 of PE. As for the compression rate, 31.9% of students in year 3 of PE, 33.0% in year 5 of PE and 45.1% in year 1 of ESO maintained an adequate rate of compressions (P = .003).

Figure 3.

Target chest compression rate and depth grid and scatterplot of depth and rate achieved by all participants in each school year. Participants that met the recommended targets are in the red area, those that came close to the targets are in the blue area.

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Only 2 students (0.98%) in year 1 of ESO delivered CPR at a depth of 50-60 mm and rate of 100-120 compressions/minute. However, 19 students of year 1 of ESO (9.27%), 4 (2.23%) in year 5 of PE (although none in year 3 of PE) managed to position themselves in the wider arbitrarily defined blue area.

Our study shows that following a brief and simple training, delivered during school hours by the physical education instructors of the schools, enabled students in years 3 and 5 of PE and year 1 of ESO (ages 8-12 years) to activate the chain of survival and initiate basic life support, although the quality of CPR was insufficient.

Similar to previous studies, we found that students in the sample were able to assimilate knowledge on first aid and BLS.14–16 In fact, the results of a small study in Italy showed that students could even have greater capacity for knowledge acquisition and retention for this type of content compared to adults,17 which would further justify teaching BLS to schoolchildren without waiting for them to reach adolescence or adulthood.

When we assessed the performance of the BLS sequence, more than half of the children performed each of the steps, a proportion that exceeded 70% in the oldest group. Although most were not able to perform the full sequence with every step in the right order, it is fair to say that they exhibited good knowledge acquisition, as reported in previous studies.14,18 It must be taken into account that carrying out each step consecutively in adherence with current guidelines is no simple task even for adults.19

Another factor at play in the delivery of basic CPR was the physical characteristics of the students, in an age range that is strongly associated with anthropometric growth. Achieving the recommended depth of compression has proven a nearly impossible goal for children under 13 years.10,20 This is not the case of other compression quality parameters that are not as dependent on height and weight, such as the chest compression fraction, correct hand positioning or full chest recoil (which happens to be easier for weaker and younger children), for which we observed proportions greater than 85%, as did previous studies.10,14,18

The percentage of compressions followed by adequate decompression decreased with increasing student age. One of the possible explanations is that younger children allow adequate thoracic decompression to occur due to anthropometric factors, as it is more challenging for them to stop the recoil of the manikin’s chest. The association between the depth of compression, chest recoil and compression rate has already been demonstrated in the context of out-of-hospital CPR.21 When it comes to the compression rate, the factors at play are not only the anthropometric characteristics of rescuers or their ability to assimilate knowledge, but also the level of psychomotor development, which determines the ability to move at a given pace, in this case, at a rate of 100-120 compressions per minute. This explains why, despite the fact that the mean rate of compressions was in the recommended target range in every group, a higher proportion of older children achieved an adequate chest compression fraction. These differences between groups in favour of older students have already been observed in previous studies.10,14,22

The Kids Save Lives statement, issued by the ERC and endorsed by the World Health Organization, has the objective of increasing survival after OHCA and promotes 10 principles, the first of which is that “kids can save lives”.1 In consequence, the school is considered the ideal setting for training with the aim of having a significant impact on the response to OHCA. In several European countries, BLS training in schools is mandatory and integrated in the academic curriculum23; in Spain, Royal Decrees 126/201424 and 1105/2014,25 which establish the primary and secondary education curricula, respectively, include training on first aid, but do not specify the contents to be taught, so that teaching of BLS and CPR is not mandatory as it is in some neighbouring countries.

The inclusion of contents related to first aid in general or BLS in particular requires adequate knowledge of this material by schoolteachers. In a study conducted in Galicia, 70.6% of surveyed teachers reported having been trained on first aid, but the vast majority answered questions about BLS incorrectly.26 Recently, the ERC has issued a position statement on the subject,27 proposing that once they have been trained, teachers can be as competent as health care professionals in teaching BLS contents. In addition, training by schoolteachers would substantially cut costs compared to having to send health care professionals to each school. Therefore, inclusion of first aid-related subjects in the educational curricula of university courses for the training of early childhood educators and primary education teachers should be considered.26,28

There are limitations to our study. The conditions of the simulation hinder the extrapolation of results to potential real-world victims. On one hand, the psychological variables that affect a real-life situation cannot be introduced in this type of simulated scenarios, and on the other, simulations are conducted on manikins, which, while being a valid and reliable instrument, do not exactly reproduce the conditions of real-world CPR, in which compression parameters are also influenced by the physical characteristics of the victim.

We used only one training method, without a control group, and the assessment was conducted immediately after completion of the training, so that it does not reflect the retention of acquired knowledge and skills in the medium and long terms.

A 2hour theoretical/practical workshop during school hours and taught by physical education instructors contributes to students learning how to identify an emergency, initiate the chain of survival and initiate basic CPR with chest compressions. The quality of compressions in terms of depth and rhythm proved insufficient. Training on BLS skills should be delivered in every school in Spain, as recommended by the World Health Organization and the ERC.

The authors have no conflicts of interest to declare.