MONDAY, Aug. 24, 2009 (HealthDay News) -- Kids should be put in car seats only when traveling, not while sleeping or "hanging out" at home, child health experts warn.
That's because sitting upright in a car seat -- the position that's recommended -- can compress the chest and lead to lower levels of oxygen, according to a new study published online Aug. 24 in Pediatrics.
"There are people who have no baby beds and have their kids sleep in the car seat all the time," noted one expert, Dr. Iley Browning, an associate professor of pediatrics at the Texas A&M Health Science Center College of Medicine. "That's not a good choice. And dropping oxygen levels are going to get worse when children have colds so you're making your child worse by putting them in a car seat when they're sick. And I guarantee that parents do this more when their child is sick."
But experts agree that the new warning by no means dilutes the message that car seats are critical for protecting children from injury in a collision, just like seat belt restraints protect adults.
"Your child should be restrained properly even for the shortest ride," said Dr. Mike Gittelman, an associate professor of emergency medicine and co-director of the Comprehensive Children's Injury Center at Cincinnati Children's Hospital Medical Center. "You're 88 percent more likely to be saved in a motor vehicle collision if you're restrained. Car seats save lives."
In addition, Gittelman said, the changes in oxygen saturation detected in the study were "minimal."
Earlier studies on the subject focused primarily on more fragile, preterm infants, he said.
But the study's authors noted that airway obstruction in an infant, even if it's mild, has been linked with behavioral problems and lower IQ.
The researchers, from Slovenia and Boston, started looking at healthy newborns when they were 2 days old, measuring oxygen saturation and other indicators while the infants were in a hospital crib for 30 minutes, a car bed (also known as a "flat car seat") for 60 minutes and a car seat for 60 minutes.
For the 200 infants included in the study, the average oxygen saturation level was 97.9 percent in the crib, 96.3 percent in the car bed and 95.7 percent in the car seat.
Greater differences were seen in average minimal oxygen levels: 87.4 percent for the hospital crib, 83.7 percent for the car bed and 83.6 percent for the car seat.
Children in car seats and car beds spent more time with oxygen levels below 95 percent than did children in cribs, according to the study. And the longer the child was in the car seat, the worse the respiratory problem became.
Car beds may be safer in this respect than car seats, but even that is not ideal, the study noted.
In addition to keeping children out of car seats for long and unnecessary periods of time, the authors suggested that manufacturers consider modifications to the design of the seats.
"It's important for people to realize that doing some of these things is not benign and has potential risks involved," said Browning, who is also a pediatric pulmonologist at Driscoll Children's Hospital in Corpus Christi, Texas. "Use the car seats when you need to, but otherwise children need to be in a different setting."
The study still leaves many questions unanswered, such as whether the oxygen effect is long-term, said Dr. Judy Schaechter, associate professor of pediatrics at the University of Miami Miller School of Medicine and director of the Injury Free Coalition for Kids of Miami.
"Does this go away after a few days or does it last three months," she said. "Clearly, if it turns out to be real, we have to look at manufacturing of car seats."
The study was funded by the Japanese company Aprica, which makes child seats, strollers and other children's products.
The American Academy of Pediatrics offers a guide to car safety seats.