|Is sleeping in a car seat dangerous?|
Last week, the AAP was at it again, playing loose with the data but tight with recommendations based upon them. This time, it's car seats. In an article in the August, 2019 edition of the journal Pediatrics, Liaw et al present data showing that, in a cohort of 11,779 infant deaths, 3% occurred in "sitting devices", and in 63% of this 3%, the sitting device was a car safety seat (CSS). In the deaths in CSSs, 51.6% occurred in the child's home rather than in a car. What was the rate of infant death per hour in the CSS? We don't know. What is the expected rate of death for the same amount of time sleeping, you know, in the recommended arrangement? We don't know! We're at it again - we have a numerator without a denominator, so no rate and no rate to compare it to. It could be that 3% of the infant deaths occurred in car seats because infants are sleeping in car seats 3% of the time!
I'm very interested in this study because if our son falls asleep in the CSS and doesn't awaken when we remove him from the car, we allow him to keep sleeping for an hour or so in the CSS. Are we being reckless? Why is it that the authors think that it is the CSS that is causing an excess risk of death above the expected rate when they don't even know the observed rate of death per hour in the car seat, nor do they know the expected rate for infants sleeping in the recommended arrangement? Well, they explain, and here are some of their points we need to consider in turn:
- CSSs should "not be used for routine sleep".
- "Sitting and carrying devices (such as CSSs) were initially designed primarily for the transporting, feeding, and play of infants and young children."
- In reference 4, 14 children died in car seats and 10 of them were not in a car at the time; and in reference 5, 30 children died in car seats.
- "If a child falls asleep in a CSS while actively traveling in a motor vehicle, they should remain in the CSS until they are no longer traveling. If they are still asleep when they are no longer traveling, they should then be placed in a crib or bassinet."
- "Despite AAP recommendations, infants often spend prolonged periods of time in CSSs when not traveling, and the CSS frequently is used as an alternative to a crib or bassinet." (Emphasis added.)
- "When compared with other deaths, infants dying in sitting devices had higher odds of having a child care provider or baby-sitter as the primary supervisor at the time of death (compared with a parent or guardian)."
- Why not? Because they (AAP) say so. (Pediatrics. 2016;138(5):e20162940). Classic petitio principii. Appropriate for children, I suppose, who often ask why and are told by a frustrated adult "because I say so."
- So, because something was designed for one thing, does it follow that it is not suitable for another? Is this Aristotelian Telos in action here? What is the evidence that the car sear was designed exclusively to be safe in a car? What features of being out of the car make it less safe there? Are there any logical responses to these questions? If so, they are not given in the article.
- These small series may have been the impetus for the current larger one, but they don't inform the relevant questions any better than it does.
- Since sleeping in a CSS is dangerous outside of the vehicle, why don't the authors and the AAP advise to keep the child awake while in the CSS in the vehicle travelling? What makes it safe for a baby to sleep in the CSS at any time, and if it is unsafe at all times, why not admonish against all sleeping in CSS? They are silent on this, perhaps because it brings the absurdity of the underlying argument into sharp relief.
- Ahh, there's the rub. The authors probably didn't realize it, but with this sentence they gave a likely explanation for their findings - that the motion of the vehicle, during even a short trip causes a fussy child to fall asleep and then he is left to sleep for several more hours outside the vehicle. Since most trips are short, this is very likely, and it reinforces the need for a rate per hour of sleep.
- If it's the CSS that is responsible for the deaths, why does it matter who leaves the child in it, unless non-parent caregivers leave the child in the car seat for longer periods? No answer is given to this obvious question either, but the likely answer is again that the exposure time to the seat is different when you analyze by caregiver classification. Now, increased exposure time is consistent with the authors' argument, but it is also consistent with no increase in the rate of SIDS while sleeping in the car seat.
Oh, and don't worry about that baby in the pic - that car is moving, so he's perfectly safe!