INTRODUCTION

Out-of-hospital cardiac arrest (OHCA) requires immediate intervention to prevent fatal outcomes and is a leading cause of death in many industrialized countries, including Japan.^1-3 Timely use of automated external defibrillators (AEDs) by lay rescuers significantly improves the chances of survival in OHCA cases.^{4, 5} The Japan Resuscitation Council Resuscitation Guidelines 2020 emphasize that when cardiac arrest is suspected, AEDs should be promptly delivered to the scene without hesitation.⁶

Schools are unique environments for AED implementation owing to the high concentration of children and adolescents. Although pediatric OHCA represents a small subset of overall OHCA incidents,^7-9 it has a significant societal impact in terms of lost productive years, healthcare costs for survivors, and emotional burden for families.⁷ Despite the increasing use of AEDs by lay rescuers for OHCA of schoolchildren in recent years, there remain some cases in which AEDs are not utilized.^{10, 11} This highlights the need for continued efforts to improve accessibility and usage of AEDs in school settings.

To ensure that AEDs are delivered more frequently to the OHCA scene in schools, identifying and addressing the factors associated with lay rescuers' AED use is essential. Understanding these factors can inform targeted educational programs and policies for enhancing emergency preparedness in schools. Therefore, this study aimed to identify the factors influencing whether lay rescuers bring AEDs to the scene of nontraumatic OHCAs among schoolchildren in Japan. Specifically, it aimed to explore the time trends in AED delivery by lay rescuers for various factors, identifying which factors showed improvement over time and which did not.

METHODS

RESULTS

Study population

Figure 1 illustrates the selection process for the study participants. Between April 2008 and December 2021, 476 nontraumatic OHCAs cases among schoolchildren were identified. Of them, 333 cases that occurred on school campuses were included in the analysis. Of the 333 OHCAs cases across the entire study period, lay rescuers brought an AED to the scene in 284 (85.3%) cases. Table 1 shows the characteristics of the study population. The study population comprised 249 (74.8%) male patients. Most OHCAs were witnessed by lay rescuers (294 [88.3%] cases) and were of cardiac origin (297 [89.2%] cases). OHCAs occurred most frequently during physical activity, with 116 (34.8%) cases occurring during sports classes and 149 (44.7%) cases during sports club activities. Most OHCAs occurred in facilities related to physical activity, with 159 (47.7%) in athletic fields, 80 (24.0%) in gymnasiums, and 32 (9.6%) in swimming pools.

TABLE 1. Factors related to bystanders' bringing AEDs to the scene of OHCA throughout the study period (2008–2021).

		Total	Bringing AEDs to the scene of OHCA by bystanders		Univariate analysis			Multivariate analysis
		N	n	(%)	RR	(95% CI)	p-value	RR	(95% CI)	p-value
Sex	Male	249	224	(90.0%)	Reference			Reference
	Female	84	60	(71.4%)	0.794	(0.689–0.915)	0.001	0.849	(0.738–0.977)	0.022
Educational stage	Elementary school	67	47	(70.1%)	0.790	(0.669–0.932)	0.005	0.839	(0.700–1.004)	0.056
	Junior high school	105	94	(89.5%)	1.008	(0.925–1.098)	0.856	0.995	(0.916–1.080)	0.898
	High school/technical college	161	143	(88.8%)	Reference			Reference
Witness of arrest	Witnessed	294	255	(86.7%)	1.166	(0.965–1.410)	0.112	1.062	(0.869–1.296)	0.558
	Not witnessed	39	29	(74.4%)	Reference			Reference
Origin of arrest	Cardiac	297	254	(85.5%)	1.026	(0.880–1.196)	0.740	0.860	(0.721–1.026)	0.095
	Noncardiac	36	30	(83.3%)	Reference			Reference
Activity at the time of arrest	Sports classes	127	116	(91.3%)	Reference			Reference
	Sports club activities	138	118	(85.5%)	0.936	(0.858–1.021)	0.138	0.927	(0.834–1.030)	0.160
	Non-sports activities	68	50	(73.5%)	0.805	(0.691–0.937)	0.005	0.764	(0.587–0.996)	0.046
Location of arrest	Athletic field	159	139	(87.4%)	Reference			Reference
	Gymnasium	80	72	(90.0%)	1.029	(0.937–1.131)	0.544	1.031	(0.945–1.125)	0.488
	Swimming pool	32	25	(78.1%)	0.894	(0.737–1.083)	0.253	0.927	(0.761–1.129)	0.450
	Classroom/other places	62	48	(77.4%)	0.886	(0.765–1.026)	0.105	1.065	(0.833–1.361)	0.614
Time of arrest	Weekdays from 8:00 to 16:00	232	199	(85.8%)	1.019	(0.923–1.126)	0.708	1.074	(0.956–1.205)	0.229
	All other times, including weekends	101	85	(84.2%)	Reference			Reference
Total		333	284	(85.3%)

• Abbreviations: AED, automated external defibrillator; CI, confidence interval; OHCA, out-of-hospital cardiac arrest; RR, risk ratio.

DISCUSSION

This study assessed the factors influencing whether lay rescuers bring AEDs to the scene of nontraumatic OHCAs among schoolchildren in Japan and investigated the 14-year trends in AED delivery. A unique feature of this study is its focus on whether lay rescuers brought an AED to the scene, rather than whether the AED was actually used. This approach provides a clear measure of lay rescuer intervention and highlights the crucial first step in the chain of survival by ensuring that an AED is promptly available at the scene. Previous studies have mostly concentrated on AED use and effectiveness,^{4, 5} but the actual usage of AEDs depends on the specific circumstances and conditions of the patient. By focusing on the act of bringing the AED, this study highlights a key aspect of lay rescuer response that is essential for improving overall emergency preparedness and outcomes. The insights gained from this research can guide improvements in emergency response protocols and lay rescuer education within school environments, supporting broader efforts in acute medicine to optimize prehospital care and enhance the effectiveness of early interventions in critical situations. Additionally, these findings could serve as valuable evidence for consideration in future updates to resuscitation guidelines, particularly in emphasizing the role of AED availability and timely intervention in prehospital settings. Our findings will inform targeted interventions and strategies to enhance AED accessibility and usage in school settings, ultimately improving survival outcomes in schoolchildren experiencing OHCA.

Our results indicate a significant year-by-year improvement in the proportion of AED deliveries by lay rescuers. This remarkable progress indicates the successful implementation of AED and resuscitation education programs in Japanese schools. Several factors contribute to this positive trend. First, the widespread distribution of AEDs in schools has likely played a significant role. In 2017, almost all public elementary, junior high, and high schools in Japan had at least one AED installed.¹⁶ Second, many teachers, staff members, and students have been equipped with the knowledge and skills to respond effectively to cardiac emergencies. As of 2017, approximately 95% of schools in Japan have conducted basic life support (BLS) training sessions for some or all staff members, and 74% have held training sessions for all staff members annually.¹⁶ BLS training for students has been provided during health and physical education classes, as stipulated by the curriculum guidelines for junior high¹⁷ and high schools.¹⁸ The proportions of schools providing hands-on training in health and physical education classes were as follows: 11.4% in elementary schools, 58.9%, junior high schools; and 66.0%, high schools. Third, the dissemination of the “ASUKA Model¹⁹” in schools across Japan has likely contributed to this positive trend. The ASUKA Model¹⁹ was developed in 2012 as a guideline for accident response in schools in response to a fatal accident that occurred at an elementary school in Saitama Prefecture in 2011. Schools nationwide have been implementing this model to enhance their emergency preparedness and response capabilities. Continued efforts to enhance these initiatives can serve as a model for other public places and contribute to further improvements in emergency response and survival rates for OHCAs.

This study also revealed that female students with OHCAs had a lower likelihood of receiving AED interventions than male students. Moreover, the improvement in AED delivery over time was less pronounced in females than in males, with no significant trend observed. Such sex disparities in lay rescuer interventions have been noted in various studies over the years.^20-23 The persistent sex disparity despite the overall improvements in AED delivery suggests that deeply ingrained social and psychological factors influence lay rescuer behavior.²⁴ A previous questionnaire survey indicated that female respondents feared inappropriate contact, whereas male respondents feared accusations of sexual assault or harassment,²⁵ both of which would be factors that inhibited the administration of lay rescuer interventions for women. Targeted interventions are essential to address these disparities. Educational campaigns should emphasize that legal protections for lay rescuers who provide emergency assistance apply equally, regardless of the patient's sex. Furthermore, training programs should include scenarios involving female patients to help normalize AED use in these situations. Featuring female rescuers and patients in training videos and campaigns can normalize AED use for women, reducing sex biases.

We also found that the proportion of AED deliveries was lower during non-sports activities compared with OHCAs occurring during sports classes. Additionally, the improvement in AED delivery over time was less pronounced in non-sports settings. One reason for this disparity can be the strategic placement of AEDs, predominantly near areas where physical activities are conducted. The most common locations for AED placement in schools were staff/visitor entrances and gymnasiums.¹⁶ Considering that most schools in Japan have only one or two AEDs,¹⁶ this placement strategy, while logical for high-risk sports events, may insufficiently cover all areas where OHCAs can occur. Furthermore, the visibility and perceived urgency of OHCAs during sports activities are relatively high, prompting a quicker and more decisive response from lay rescuers. Sports activities are often closely supervised, and the physical exertion involved increases the risk of cardiac events. By contrast, non-sports activities may not have the same level of supervision or immediate recognition of cardiac emergencies, leading to delayed responses. BLS training that simulates OHCAs in various locations can also improve lay rescuer readiness and response times, regardless of the activity or location. Enhancing awareness of the importance of AED accessibility in all areas of schools can help create a more comprehensive emergency preparedness strategy, ultimately improving the outcomes for all students. Furthermore, increasing education and training for students, who are often the bystanders present during emergencies, is also essential to improve overall emergency response readiness and outcomes in schools.

CONCLUSION

The present study investigated the factors affecting lay rescuer AED delivery in the context of nontraumatic OHCAs among schoolchildren in Japan. The proportion of AED deliveries by lay rescuers significantly increased from 73.7% in 2008–2010 to 93.3% in 2020–2021. However, there is still room for improvement, particularly in female patients and incidents during non-sports activities. Addressing these gaps requires further efforts to fulfill the stated aim of the AED Committee of the Japanese Circulation Society to achieve “zero sudden cardiac deaths in schools.”²⁶

CONFLICT OF INTEREST STATEMENT

The authors declare no conflicts of interest.

ETHICS STATEMENT

Approval of the research protocol: The study protocol was approved by the Ethics Committees of Otsuma Women's University and Osaka University.

Informed consent: Personal identifiers were removed from the database, and the requirement for informed consent was waived.

Registry and registration no. of the study/trial: This study was not registered.

Animal studies: N/A.