Out-hospital cardiac arrest (OHCA) is an important health problem associated to cardiovascular disease, due to its high incidence and mortality.1–3 A study conducted in 37 European countries found the annual incidence of OHCA attended by the emergency medical services to be 38 cases per 100,000 inhabitants.2 However, the on-site management of such cases is ineffective, since it is typically applied late, despite scientific evidence that early basic cardiopulmonary resuscitation performed by witnesses of the event can result in a three- to four-fold increase in the patient chances for survival.4 Thus, early basic life support (BLS) maneuvering is necessary in order to improve the prognosis of OHCA – including immediate defibrillation if available, since it forms part of the third link in the patient chain of survival.5 Early defibrillation and public access to automated external defibrillators (AEDs) have been shown to increase the chances for survival to 74%.6–10 When carried out in the first 3–5min after collapse, survival rates of up to 50–70% have been reported,11–13 provided the previous steps—i.e., recognition of cardiac arrest (CA), activation of the emergency system and start of CPR maneuvering—have been correctly executed. In this regard, the chances for survival decrease between 7 and 10% for every minute of delay.14

On the other hand, insufficient awareness and capacitation on the part of the general population in dealing with OHCA,15 and the lack of training in how to deal with an emergency, have suggested the need to incorporate instruction on the use of an AED to the protocolized educational setting in order to palliate this situation. Knowing how to apply BLS techniques means knowing how to save lives.16 In this regard, we can speak of a strategy for population-based access to public defibrillators, with the implementation of different programs—some of which have already been tested in practice.8,17,18 It has been shown that the first individuals to intervene (usually laypersons)19,20 can safely use a defibrillator, regardless of whether they have received basic training in its use or not.8,9

The present study aims to analyze the use and time taken by university students to apply a discharge with the AED, since it is considered that a good setting in which to start the chain of training in BLS techniques (including the handling of AEDs) would be the teacher training schools. In effect, once these university students become teaching professionals, they will be the individuals in closest contact with the children of the future, and thus may contribute to transmit this kind of knowledge in schools over the long term, providing instruction for as many people as possible. Furthermore, according to the observations of previous studies, both laypersons and children can use an AED without training.21,22

The objective of this study is therefore to analyze knowledge and skills referred to the use of the AED among a population of students of the University of Santiago de Compostela (Spain), without prior training or experience with BLS, and centered on their capacity to administer defibrillation with an AED—measuring the time taken to apply the discharge in three different scenarios: initially, without previous training; after a brief visual and theoretical explanation lasting less than one minute; and 6months after such training activities.

The analysis of the results obtained in relation to university student knowledge of the use of the AED is described below.

Of the 129 students included in the study, 71.3% did not know what an AED is (P-K); 100% claimed to have received no prior training (P-T); and 100% had never used the device before (P-U) (Table 1).

A total of 28.7% of the university students had heard about AEDs, but had not received training or used the device before.

The results referred to the mean time (in seconds) taken by the students in applying a discharge with the AED were: T0=67.7 (SD=15.6) s; T1=44.2 (SD=6.3) s; T2=45.9 (SD=5.8)s. The mean time taken in applying a discharge among the emergency healthcare technicians was 51.9 (SD=9.7)s.

Table 2 shows the results of the repeated measures analysis of the mean times to defibrillation among the university students in the different moments of the study. Within-subject contrast testing revealed significant interaction between the time taken to deliver a discharge and the moment in which the time was recorded (T0, T1 and T2) – 66.5% of the variance of the study being explained by interaction of the factors F(1,128)=253.79 (p<0.001; Eta2p=0.665). This means that there were statistically significant differences among the three time measurements, i.e., the observed differences were not attributable to chance. A decrease of 23.4s in mean defibrillation time was observed after having received training (“improvement effect”) (34.6%). The defibrillation time in turn increased an average of 1.6s as measured after 6 months (T2) (3.7%) (“degree of forgetfulness effect”), but was still shorter than the mean time recorded at T0.

The variable “improvement effect” was not influenced by either gender (p=0.540) or age (p=0.124) – T0 being the only variable conditioning the decrease in time registries (p=0.004). Likewise, neither gender (p=0.637) nor age (p=0.272) exerted an influence upon the variable “degree of forgetfulness effect”.

Table 3 shows the results of the bivariate comparative analysis of the mean defibrillation times of the university students in the different moments of the study.

After the brief basic training provided, the time taken in delivering a discharge was seen to decrease 34.6%. Six months after the training received, the time was found to have increased an average of 1.6s.

On the other hand, regarding the results of the multivariate analysis of the mean defibrillation times of the university students in the different moments of the study, compared with the times recorded in the control group (emergency healthcare technicians), between-subject contrast testing revealed F (time 1)(1,148)=19.08 (p<0.001); F (time 2)(1,148)=21.71 (p<0.001) and F (time 3)(1,148)=15.04 (p<0.001). This means that there were statistically significant differences among the three time measurements, i.e., the observed differences were not attributable to chance – time 1 being understood as (T0us and T0eht); time 2 as (T1us and T0eht), and time 3 as (T2us and T0eht).

The present study shows the capacity of laypersons (university students) both without and with brief training to use an AED, compared with a group of trained staff. The findings confirm that defibrillation performed by first intervening individuals using a public access ARD is a feasible and effective strategy, in concordance with the observations in other settings, such as Japan, where excellent results were recorded in real interventions.8 Indeed, even 9-year-old children are able to understand the importance of CPR performed by witnesses, and can learn to apply BLS measures and retain the knowledge gained.26,27

The data obtained show that skill in using the AED after a brief (no more than 60s) explanation of how the device is employed and handled is noticeably greater than when the AED is used without any type of training. Specifically, the time required was found to decrease by 34.6%. This result is also 7.7s better than that obtained by the trained staff (emergency healthcare technicians). The explanation for this could be that most BLS training courses involve teamwork by two individuals: a first technician starts continuous cardiac massage, while the other member of the team is in charge of telephone activation of the emergency service switchboard and fitting of the AED. In this context, the technicians are more thoroughly trained in such aspects and in the quality of cardiac massage—with less emphasis being placed on immediate rapidity of execution.

On the other hand, the response time barely increased among the layperson sample after 6 months (−3.7%), and remained significantly better than the time taken in the absence of any previous training (about 23.4s). It therefore can be concluded that there is good retention of the skills gained, and in contrast to the situation in the case of thoracic compression maneuvers,28 no reinforcement training would be needed in under 6 months, since the time taken to deliver the discharge was seen to increase very little.21

This 22-s difference in skill retention cannot be attributed to biological aspects of the participants, since their ages were similar, and moreover studies are available corresponding to individuals of younger age in which long-term retention was found to be similar.22 Based on the results obtained, it is seen that skills in using an AED are easily gained and retained, independently of the age of the individual.

If laypersons were able to make use of a defibrillator several minutes before the arrival of professional help, the survival rates could be improved to about 49–75%.10 This is of great importance, since an early defibrillation program has a better chance for success if the time elapsed from CA to defibrillation is under 12min.29

On the basis of the results obtained, and as reflected by the European Resuscitation Council (ERC), AEDs can be regarded as safe and effective when used by both laypersons and medical staff.24 The Spanish Cardiopulmonary Resuscitation Council considers liberalization of the non-negligent use of AEDs by untrained non-sanitary staff (citizens in general) to be adequate when done with the intention of helping a CA victim.30

The results obtained in this investigation support the recommendations of the Spanish Cardiopulmonary Resuscitation Council,30 the ERC24 and the AHA,23 since university students—as a sample of general citizens without training in the use of defibrillators—can apply a discharge with the AED if necessary.

All this would reinforce implementation of the strategy proposed in 1992 by the AHA,31 whereby placing the AED in the hands of a great number of people capable of using the device could represent the key intervention for increasing the chances of survival among patients with OHCA. The generalized effectiveness and safety demonstrated by the AED make it acceptable for effective handling by non-professionals,8 in conjunction with the necessary recommendations and instructions received from the urgencies and emergencies coordination centers by telephone.32

In the context of training in BLS, the recognition of OHCA, activation of the emergencies system and the start of basic CPR maneuvering are crucial elements, followed by the use of the AED (if available) as the third link in the chain of survival. However, it must be mentioned that mere use of the AED alone is not enough: correct execution of the previous steps is equally important.5 For this reason, citizen training in BLS is essential, even when the programs used for this purpose are very brief, as demonstrated in the present study.

These contents should be incorporated to the training of future teachers, with a view to reaching as much of the population as possible. In this regard, teachers are regarded as targets for training since they in turn can become future instructors in their own classroom settings,33,34 transmitting this knowledge to the children in the morning, with the aim of achieving the goal of the ERC,5 i.e., to ensure that defibrillation with the AED occurs between 3 and 5min after patient collapse, though the adoption of programs contemplating public access to devices of this kind.

Consensus is still lacking regarding the timelines for a training program in AED, though our study could be a starting point for implementing public access to early defibrillation, since the AED is easy to handle. The university students, as laypersons without training, were able to perform defibrillation without prior instruction.

Training is simple, and should be carried out in the context of the university education of teacher training school students, as possible future teachers of children who in turn can receive the necessary knowledge and offer better chances for survival among people who suffer OHCA.

No funding was received for this investigation or preparation of the article.

All the authors have participated in all parts of the investigation and in preparation of the manuscript (study conception and design, data acquisition, data analysis and interpretation, drafting of the manuscript, critical review of the intellectual content, and definitive approval of the manuscript).

The authors declare that they have no conflicts of interest.