Sex Disparities in Receipt of Bystander Interventions for Students Who Experienced Cardiac Arrest in Japan

This cohort study examines sex disparities among youths who experienced cardiac arrest in schools in receipt of public-access automated external defibrillator pad application and cardiopulmonary resuscitation from bystanders in Japan.


Introduction
Out-of-hospital cardiac arrest (OHCA) is an important public health issue in resource-rich countries, [1][2][3][4] and the survival rate of OHCA remains low. [5][6][7] Pediatric patients who experience OHCA accounted for only 3% of all patients who experience OHCA in Japan. [8][9][10] However, OHCA and sudden OHCA-associated death among children have significant negative impacts on a community in terms of life-years lost, health care costs for survivors, and emotional burden for family members. 11 Therefore, evaluating factors for improving survival after pediatric OHCA is important in resuscitation science.
As recommended in the cardiopulmonary resuscitation (CPR) guidelines, 1-3 bystanders performing CPR and using a public-access automated external defibrillator (AED) are important factors for improving survival outcomes in OHCAs. Previous studies have reported that women experiencing OHCA in public locations were less likely to receive bystander-initiated CPR compared with men, [12][13][14] and girls aged 12 to 17 years who experienced OHCA witnessed by nonfamily members were less likely to receive bystander-initiated CPR than boys. 15 Additionally, El-Assaad et al 16 reported that children aged 2 to 11 years experiencing OHCAs were less likely to receive AED pad application than children aged 12 to 18 years. Thus, resuscitation behaviors of lay rescuers might change depending on the age and sex of the individual experiencing OHCA. In particular, schoolchildren spend most of their active hours of the day in schools, but to our knowledge, no clinical studies have been conducted to assess sex disparities in receiving public-access AED pad application and bystander-initiated CPR in school settings.
We commenced a nationwide prospective observational study of youths who experience OHCA occurring in school settings in Japan, called the Stop and Prevent Cardiac Arrest, Injury, and Trauma in Schools (SPIRITS) study. 17 Using this database, we evaluated whether there are sex differences by school level in receiving public-access AED pad application or bystander-initiated CPR among youths experiencing OHCA in school settings.

Ethical Review
This study conformed to the principles of the Declaration of Helsinki, 18 19 Data on approximately 1.1 million injury and unintentional injury cases were reported and registered annually from nearly 73 000 schools and nurseries nationwide during the study. 19 In Japan, 98.0% of high schools, 89.8% of junior high schools, and 72.0% of elementary schools had at least 1 public-access AED in 2008; in 2015, 99.7% of high schools, 99.9% of junior high schools, and 99.9% of elementary schools had at least 1 public-access AED. 20 The All-Japan Utstein Registry is a population-based OHCA registry based on the international Utstein format 21,22 and covers the entire population of Japan (approximately 127 million people). In this registry, cardiac arrest is defined as the cessation of cardiac mechanical activity confirmed by the absence of signs of circulation, and OHCA data are recorded by emergency medical service (EMS) personnel in cooperation with the physician in charge of the patient. Since prehospital termination of resuscitation by EMS personnel is generally not allowed in Japan, most patients experiencing OHCA cared for by EMS personnel are transported to hospitals, and the data are recorded in this registry, except for patients who are not transported to a hospital by EMS (ie, transported to a hospital by family members or bystanders, non-EMS transporting vehicles, or air ambulance). Thus, the SPIRITS database, which was developed by merging these 2 nationwide registries, has retained the data for most pediatric patients who experienced OHCA in school settings in Japan from April 1, 2008, to December 31, 2015. Data analysis was performed from January 5, 2019, to April 11, 2019.

Study Participants
Youths from elementary schools (ages 6-12 years), junior high schools (ages 12-15 years), high schools (ages 15-21 years), and technical colleges (ages 15-21 years) in Japan who experienced nontraumatic OHCA from April 1, 2008, to December 31, 2015, were included in this study. Youths in whom a resuscitation attempt was performed by EMS personnel or bystanders were included. Youths whose OHCA occurred after EMS arrival, was caused by trauma (eg, vehicle crashes, falling incidents, and hanging), occurred outside the school campus, or had unknown first documented rhythm were excluded from the analyses.

Data Collection
We obtained the following data from the SPIRITS database: date and time of emergency call by bystanders, time of contact with patient by EMS personnel, time of arrival at hospital, region, school level, sex, age, whether the OHCA occurred during class time or extracurricular activities, location of cardiac arrest, whether the cardiac arrest was witnessed, cardiac origin of arrest, first documented rhythm, bystander-initiated CPR, and application of public-access AED pads. Based on a 2013 study, 23 we classified regions in Japan as Hokkaido-Tohoku, Kanto, Tokai-Hokuriku, Kinki, Chugoku-Shikoku, and Kyushu-Okinawa. The end points of this study were bystander interventions for students experiencing OHCA (ie, application of public-access AED pads or initiation of CPR by a bystander).

Statistical Analysis
Summary statistics were expressed by mean and SD for numerical variables and percentages for categorical variables. Among the eligible students who experienced OHCA, student and EMS characteristics were compared between sexes using the χ 2 test for categorical variables and t test or Mann-Whitney U test for numerical variables. In addition, the regional and age distributions between sexes were evaluated by school level. Univariable and multivariable logistic regression analyses were conducted to assess sex differences in the application of public-access AED pads and bystanderinitiated CPR. In multivariable analysis, odds ratios (ORs) and their associated 95% CIs were calculated by using multivariable logistic regression, adjusting for region, location of cardiac arrest, school level, whether the cardiac arrest was witnessed, whether the cardiac arrest occurred during class time or extracurricular activities, and cardiac origin of arrest. In addition, since sex differences in the initiation of bystander interventions would vary by school level, ORs and 95% CIs were estimated for each school level by using an interaction of sex and school level in the multivariable model, adjusting for region, location of cardiac arrest, school level, whether the cardiac arrest was witnessed, whether the cardiac arrest occurred during class time or extracurricular activities, and cardiac origin of arrest.

JAMA Network Open | Emergency Medicine
All tests were 2-tailed, and a P value of less than .05 was considered statistically significant.
Statistical analyses were conducted using Stata statistical software version 15.0 MP (StataCorp).

Results
The Figure shows

Discussion
From the nationwide SPIRITS database in Japan, we assessed differences in receiving public-access AED pad application and bystander-initiated CPR between male and female students who experienced an OHCA in a school setting. We found that female sex was associated with lower odds of receiving public-access AED pad application compared with male sex, and the association remained after adjusting for potential confounders. There were no significant differences in receiving bystander-initiated CPR between sexes. To our knowledge, this was the first attempt to assess sex differences in receiving public-access AED pad application and bystander-initiated CPR in schools, where school-aged youths spend most of their active hours of the day. The results of this study would be useful for future revisions of school CPR education programs and for improving survival from pediatric OHCA in school settings.
To our knowledge, there are few previous studies that have evaluated AED pad application among youths who experienced OHCA. In the only previous study assessing factors associated with AED pad application for pediatric OHCA, to our knowledge, El-Assaad et al 16 reported that a factor associated with AED pad application in the United States was age: children aged 2 to 11 years who experienced OHCA were less likely to receive AED pad application compared with youths aged 12 to  18 years. El-Assaad et al 16 speculated that this was because there was a lack of CPR knowledge and confusion about AED use for children among bystanders. There were no significant differences in receiving AED application between sexes, and they did not assess sex differences in receiving AED pad application by school level or age group.
Our study found that female sex among youths who experienced OHCA in schools was associated with significantly lower odds of receiving public-access AED pad application than male sex among youths who experienced OHCA in schools. The reason for this sex difference in receiving public-access AED pad application is unclear. We speculate that it may be because bystanders must undress a person experiencing OHCA to apply AED pads, but chest compressions can be conducted without undressing. Bystanders might be embarrassed and afraid of applying AED pads on schoolaged female youths because undressing women and girls is an unfavorable behavior in public places, even if they are experiencing cardiac arrest, and for male bystanders to do so, it might be misunderstood as sexual assault.
In this study, more than 80% of youths who experienced OHCA received CPR from a bystander, should be continuously carried out in schools for staff and students to achieve the Japanese Circulation Society's goal of no deaths of sudden cardiac arrests in schools. 26 Because female sex among students who experienced OHCA in schools was associated with lower odds of receiving public-access AED pad application than male sex, we must educate school staff and students on the recognition of OHCA as well as the proper use of AED via CPR education and training so that they can apply AED pads for female students experiencing OHCA without hesitation.
Almost all elementary, junior high, and high schools in Japan have installed at least 1 AED. 25 To further increase the implementation of AED pad application regardless of sex, public-access AEDs should be located in school buildings as well as in school athletic areas, such as the schoolyard, pool, and gymnaseum, 27 so that AED interventions can be delivered within 5 minutes, based on Japanese recommendations on the deployment criteria of public-access AEDs. 28

Limitations
This study has several inherent limitations. First, our study did not obtain information regarding the sex of bystanders performing CPR or their experience with previous CPR training. Second, the concern of undressing an older girl might be a barrier to AED placement. For example, there are some all-girls schools in Japan, but we did not obtain information on whether schools where the cardiac arrests occurred were single-gender schools. However, only 7% of schools in Japan are all-girls schools, 29 so the impact of all-girls schools on our data would be small. Third, the implementation of public-access AED pad application and bystander-initiated CPR were our main outcome, and the survival outcome after OHCA between sexes was not evaluated in this study. Survival after OHCA is significantly affected by other factors, such as witness status, first documented rhythm, and treatments by EMS personnel and medical institutions as well as the provision of bystander-initiated CPR. Fourth, our findings may not be fully generalizable to other health care settings, given the differences in patient characteristics and medical care systems. Fifth, there is a possibility of input errors in the items for data linkage for the development of the SPIRITS database, which could lead to underestimation of OHCA cases to a certain degree. Moreover, the exclusion of participants who were not transported to the hospital by EMS personnel could also cause underestimation of OHCA incidence. Additionally, there may be unmeasured confounding factors that might have influenced the association of sex with AED pad application.

Conclusions
Female sex among students who experienced OHCA in schools in Japan was associated with lower odds of receiving public-access AED pad application compared with male sex, and the association remained after adjusting for potential confounders. Observational studies in other countries are essential to verify sex disparities in receiving public-access AED pad application among school-aged youths who experience OHCA and to confirm our results.