Survival From Pediatric Out-of-Hospital Cardiac Arrest During Nights and Weekends

Background Disparities in survival after pediatric out-of-hospital cardiac arrest (OHCA) between on-duty hours and off-duty hours have previously been reported. However, little is known about whether these disparities have remained in recent years. Objectives This study aimed to examine the association of outcomes after pediatric OHCA with time of day and day of week. Methods This observational study analyzed the Japanese government-led nationwide population-based registry data of OHCA patients. Pediatric (<18 years) patients who experienced OHCA between 2012 and 2017 were included. A multivariable logistic regression model was used to examine the association of both time of day (day/evening vs night) and day of week (weekday vs weekend) with outcomes after OHCA. The primary outcome was 1-month survival. Results A total of 7,106 patients (mean age, 5.7 ± 6.5 years; 60.9% male) were included. 1,897 events (26.7%) occurred during night hours, and 2,096 events (29.5%) occurred on weekends. Overall, 1,192 (16.8%) survived 1 month after OHCA. After adjusting for potential confounders, 1-month survival during day/evening (1,047/5,209 [20.1%]) was significantly higher than that at night (145/1,897 [7.6%]) (adjusted odds ratio: 2.31 [95% CI: 1.87–2.86]), whereas there was no significant difference in 1-month survival between weekdays (845/5,010 [16.9%]) and weekends (347/2,096 [16.6%]) (adjusted odds ratio: 1.04 [95% CI: 0.88–1.23]). Conclusions One-month survival after pediatric OHCA remained significantly lower during night than during day/evening, although disparities in 1-month survival between weekdays and weekends have been eliminated over time. Further studies are warranted to investigate the mechanisms underlying decreased survival at night.

O ut-of-hospital cardiac arrest (OHCA), a leading cause of mortality, is a major public health concern worldwide. 1-5 In the United States, an estimated 155,000 to 350,000 cases of OHCA occur annually, and the survival rates of OHCA are 9% to 10%. 2,6-8 Pediatric cases account for 2% to 6% of all OHCA cases, and their survival rates are 6% to 13%. 6,[9][10][11] In Japan, approximately 130,000 cases of OHCA occur annually, and <10% survive. [12][13][14] The survival rate from pediatric OHCA, which accounts for approximately 1% of the total patients with OHCA, remains low (17%-19%), 12,15,16 although it is higher than that of adult cases of OHCA.
To improve treatment outcomes, Japan's health policy has promoted the establishment of more emergency and critical care centers that can provide advanced and highly specialized care for critically ill and injured pediatric patients 24 hours a day, 365 days a year (Supplemental Table 1). 12,17 Although a previous study in Japan demonstrated worse survival for pediatric OHCA (who were treated from 2005 to 2011) during nights or weekends compared with days/evenings or weekdays, 16 much less is known about how survival differences between off-duty hours (ie, nights and weekends) and on-duty hours (ie, days/evenings and weekdays) change over time through the increase in emergency and critical care centers. This information is important for evaluating the effectiveness of Japan's health policy and identifying opportunities for quality improvement in pediatric resuscitation.
To address this knowledge gap, we evaluated survival rates for pediatric cases of OHCA (who were treated from 2012 to 2017) by time of day and day of week. We hypothesized that survival rates from pediatric OHCA presenting during off-duty hours would be similar to those during on-duty hours in recent years.

METHODS
STUDY DESIGN AND DATA SOURCE. This study was a registry-based analysis of pediatric OHCA patients in Japan. The All-Japan Utstein Registry is a government-led nationwide population-based registry of OHCA patients managed by the Fire and Disaster Management Agency (FDMA). OHCA related terminology is followed by the Utstein definitions. 1,12,18 As previous studies have described in detail, [13][14][15][16] trained emergency medical service (EMS) personnel prospectively collected data on all OHCA patients who were transported to an emergency hospital by using Utstein-style uniform reporting. 18,19 During the study period, almost all OHCA patients in Japan were included in this registry regardless of whether they had do not resuscitate (DNR) orders, because EMS personnel in Japan are not allowed to terminate out-of-hospital resuscitation except in specific situations (eg, decapitation, rigor mortis, livor mortis, or decomposition).
The FDMA collected data from 3 sources (ie, 1-1-9 dispatch centers, fire stations, and receiving hospitals) and integrated them into the All-Japan Utstein Registry system on the FDMA database server. The integrity, accuracy, and completeness of the data were ensured through logical internal checks with standardized software and FDMA certification. Japan has a nationally uniform EMS system with universal health coverage. 20 12 We also excluded patients with missing, incomplete, or inconsistent data, which accounted for <1% of all OHCA patients ( Figure 1).

The institutional review board of Toranomon
Hospital and University of the Ryukyus approved this study with a waiver of informed consent due to the anonymous nature of the data. The study was conducted in accordance with the amended Declaration of Helsinki.   OUTCOMES. The primary outcome of our analysis was survival 1 month after OHCA. The secondary outcomes were prehospital return of spontaneous circulation and favorable neurological status 1 month after OHCA, defined as a Glasgow-Pittsburgh cerebral performance category score of 1 (good performance) or 2 (moderate disability). 18,24 STATISTICAL ANALYSIS. Descriptive statistics were used to characterize the study cohort. Categorical   As an ancillary analysis, a comparison between the current study and the previous study of pediatric OHCA in Japan was also conducted. In conformity with the previous study, 16

RESULTS
During the study period, we identified 7,106 eligible pediatric patients with OHCA ( Figure 1). The baseline characteristics are shown in Table 1   In the ancillary analysis (Supplemental Table 2

DISCUSSION
In this nationwide population-based observational study of pediatric OHCA, the rate of 1-month survival  Table 1). 12,17 Considering that the survival disparity between day/evening and night was larger than that between weekdays and weekends in the previous study, 16 25 The survival disparity between day/evening and night was observed even in mature adult EMS system in Japan. If we expand the scope of the search from OHCA to include in-hospital cardiac arrest (IHCA), a larger study (treating 12,404 pediatric IHCA patients in North America from 2000 to 2012) can be identified. 26 That study found that the rate of survival from pediatric IHCA was lower during the night than during day/evening (adjusted OR: 0.88 [95% CI: 0.80-0.97]), but did not differ between weekends and  Values are n (%), unless otherwise indicated. The association between day of week (weekday vs weekend) and 1month survival after pediatric OHCA was reported as adjusted ORs with 95% CIs. a 57 patients for whom 1-month neurological status was not available were excluded from analysis.
Abbreviations as in Table 2. This study examined whether the rate of survival after pediatric out-of-hospital cardiac arrest was affected by the time of day or day of the week when the event occurred. The rate of 1-month survival was lower at night than during the day/evening, whereas there was no difference in 1-month survival between weekday and weekend.   The associations between time of day (day/evening vs night) and 1-month survival after pediatric out-of-hospital cardiac arrest were reported as adjusted ORs with 95% CIs for the prespecified subgroups according to age (0 years, 1-7 years, or 8-17 years) and etiology of arrest (cardiac, external, or noncardiac nonexternal cause).
Multivariable logistic regression models were performed by including the same set of variables used in the primary analyses.
can eliminate survival disparities between day/evening and night.

CONCLUSIONS
We found that the rate of 1-month survival after pediatric OHCA was lower at night compared with day/evening, whereas there was no difference be- TRANSLATIONAL OUTLOOK: Further research should explore the underlying causes of survival disparities between day/evening and night. A clearer understanding of the reasons for these disparities will play an important role in policy making to achieve parity in treatment outcomes between on-duty hours and off-duty hours among critically ill and injured pediatric patients.