Children left in hot cars: Data and research

 
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As the weather warms, government agencies begin to warn families about the dangers of leaving children in hot vehicles. Each year, dozens of youngsters die in parked cars, where temperatures can rise rapidly even on cool days. In 2016, heatstroke killed 39 kids, according to the National Highway Traffic Safety Administration (NHTSA). Already in 2017, news reports have chronicled the deaths of two sisters in Texas, a 5-year-old Arkansas boy who was left in a day-care van and others.

In many states, it’s illegal to leave a kid unattended in a car. In June 2017, three members of Congress introduced a bill that would require new automobiles to be equipped with systems for alerting the driver if a passenger is in the back seat after the vehicle is turned off.

To help reporters understand this important topic, Journalist’s Resource has gathered several key research studies and reports, including those that examine the conditions inside a vehicle that contribute to heat stroke.

Another helpful resource is NoHeatStroke.org, a website run by a meteorologist at San Jose State University who tracks media reports of child deaths in parked cars. Some prominent groups working to raise awareness are KidsAndCars.org and Safe Kids Worldwide.

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Estimates of child deaths

“Retrospective Analysis of Heat Stroke Deaths of Children in Motor Vehicles”
National Center for Statistics and Analysis. Traffic Safety Facts Research Note, December 2015.

This report explains why numbers released by the NHTSA for heat-stroke related deaths of children are generally lower than what is reported by other sources. The NHTSA collects information from death certificates. For children who died of suspected heat stroke, the official cause of death is sometimes listed as “fever, unspecified” or “assault (homicide) by other specified means” or “neglect and abandonment.” These children would not be included in the NHTSA’s tally of children who died of heat stroke in parked vehicles.

 

“Not-in-Traffic Surveillance: Non-Crash Fatalities and Injuries”
National Center for Statistics and Analysis, Traffic Safety Facts Research Note, March 2015.

Summary: “This Research Note provides updated information on fatalities and injuries among the overall population as well as among children 14 and younger who were involved in ‘motor vehicle non-crash incidents’ (herein referred to as non-crash incidents). The data on such incidents are obtained by the National Highway Traffic Safety Administration (NHTSA) through its Not-in Traffic Surveillance system. These updates reflect non-crash fatality data from 2005 to 2007 and injury estimates in 2011 and 2012.”

 

Circumstances leading to death

“Hyperthermia Deaths Among Children in Parked Vehicles: An Analysis of 231 Fatalities in the United States, 1999–2007”
Booth III, John N.; Davis, Gregory G.; Waterbor, John; McGwin Jr., Gerald. Forensic Science, Medicine, and Pathology, 2010. DOI: 10.1007/s12024-010-9149-x.

Abstract: “Motor vehicle-related child hyperthermia fatalities (MVRCHF) have risen slightly in the past decade, but little research has been done investigating the circumstances surrounding MVRCHF. In order to address gaps in our understanding, the current study describes MVRCHF circumstances among children <1–14 years of age in the United States from 1999 to 2007. Three sources were used to identify child hyperthermia death cases in the United States from 1999 to 2007: the Centers for Disease Control and Prevention’s Compressed Mortality File (1999–2004), the Golden Gate Weather Service’s public MVRCHF database (2003-Present), and an independent internet search. Data about the victim’s characteristics and the circumstances surrounding the death were extracted. From 1999 to 2007, 231 MVRCHF were identified. Children were left unattended in >80 percent of cases, 25 percent of victims were playing at the time of death, and 60 percent were male. On average, the core body temperature was 107.2 degrees F after being left inside the vehicle for an average of 4.6 hours. The largest number of deaths occurred in the South, followed by the West, Midwest, and Northeast. Parents were found to be accountable for 2/3 of the hyperthermia deaths. The geographic distribution of incidence may be attributable to two major influences: (1) regional climate differences; and (2) population characteristics. The accountability of parents for MVRCHF is likely due to the exposure-risk concept, in which the situation/circumstances increase the injury probability.”

 

How automobiles contribute to heat stroke

“Impact of Dangerous Microclimate Conditions within an Enclosed Vehicle on Pediatric Thermoregulation”
Grundstein, Andrew; Duzinski, Sarah; Null, Jan. Theoretical and Applied Climatology, 2017. DOI: 10.1007/s00704-015-1636-2.

Abstract: “Pediatric vehicular hyperthermia (PVH) persists as the leading cause of non-crash, vehicle-related deaths among U.S. children with an average of 37 children dying after being left unattended in motor vehicles each year. Our study aims to demonstrate the microclimate conditions within an enclosed vehicle that lead infants and small children to reach key physiological heat thresholds: uncompensable heating (>37 degrees C) and heatstroke (>40 degrees C) under ‘worst case’ conditions. A modified version of the Man-Environment Heat Exchange Model was used to compute the length of time for an infant to reach these thresholds. Several different scenarios were modeled using different initial cabin air temperatures. Assuming full sun exposure and maximum heating rates, an infant may reach uncompensable heating within 5 minutes and experience hyperthermia anywhere from 15 to 55 minutes depending on the starting cabin air temperature. The rapid approach of these heat-related thresholds occurs as enclosed vehicles maximize heating and minimize cooling mechanisms, leading to net heating and increase in core body temperatures. Health experts can use this information to support public health messaging on the topic of PVH by explaining why it is important to never leave a child alone in a car and increase the public perception of severity and susceptibility to this ongoing public health issue.”

 

“Heat Stress from Enclosed Vehicles: Moderate Ambient Temperatures Cause Significant Temperature Rise in Enclosed Vehicles”
McLaren, Catherine; Null, Jan; Quinn, James. Pediatrics, 2005. DOI: 10.1542/peds.2004-2368.

Conclusions: “Even at relatively cool ambient temperatures, the temperature rise in vehicles is significant on clear, sunny days and puts infants at risk for hyperthermia. Vehicles heat up rapidly, with the majority of the temperature rise occurring within the first 15 to 30 minutes. Leaving the windows opened slightly does not significantly slow the heating process or decrease the maximum temperature attained. Increased public awareness and parental education of heat rise in motor vehicles may reduce the incidence of hyperthermia death and improve child passenger safety.”

 

How young bodies are impacted

“Fatal Heat Stroke in Children Found in Parked Cars: Autopsy Findings”
Adato, Berliz; et al. European Journal of Pediatrics, 2016. DOI: 10.1007/s00431-016-2751-5.

Abstract: “A common and unfortunate cause for heat stroke-related deaths in children is entrapment in closed vehicles. The aim of this study was to analyze the pathological consequences of such grave events. Autopsy reports of all children that were brought to a national forensic medicine center after being found dead in closed vehicles over a 21-year period (1995–2015) were reviewed. Data extracted were the circumstances of the events, child age, sex, height and weight, time, date and duration of entrapment, and environmental temperatures at the time of entrapment and the autopsy findings. Eight deceased children were brought to the forensic medicine center for autopsy, and seven families consented to the procedure. Autopsy findings included diffuse petechiae and hemorrhages of serosal membranes (n = 7/7) and lung congestion (n = 3/7).”

 

“Evaluating Infant Core Temperature Response in a Hot Car Using a Heat Balance Model”
Grundstein, A.J.; et al. Forensic Science, Medicine and Pathology, 2015. DOI: 10.1007/s12024-014-9619-7.

Results: “In all four seasons, despite differences in starting temperature and solar radiation, the model infant reached heat stroke and demise before 2:00 pm. Time to heat stroke and demise occurred most rapidly in summer, at intermediate durations in fall and spring, and most slowly in the winter. In August, the model infant reached un-compensable heat within 20 min, heat stroke within 105 min, and demise within 125 min. The average rate of heating from un-compensable heat to heat stroke was 1.7 degrees C/hour (3.0 degrees F/hour) and from heat stroke to demise was 4.8 degrees C/hour (8.5  degrees F/hour).”

Last updated: June 19, 2017

 

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