to the editor: We would like to commend Dr. Biagioli on the excellent article, “Proper Use of Child Safety Seats.”¹ However, some clarification of issues regarding the most recent guidelines for best practices is needed.

Dr. Biagioli correctly explains the benefits of keeping infants rear-facing until they weigh 20 lb and reach one year of age. However, the benefits do not stop for children who are over one year of age and 20 lb. Guidelines from the American Academy of Pediatrics² state that a child in a convertible seat can remain rear-facing until they reach the upper weight limit of the seat (30 to 35 lb), provided the top of their head remains at least one inch below the top of the child restraint. While the child's feet may touch the vehicle seatback, this is not a problem unless it causes excessive discomfort for the child. For parents concerned about the potential risk of leg injury, an appropriate response is that broken legs heal more easily than broken necks. We have both kept our children rear-facing until 30 lb (at age 20 months and 24 months, respectively). In addition, the recommended 45-degree angle for rear-facing child restraints applies only to small infants so they can maintain an open airway. For older infants and toddlers, a more upright seat provides superior crash protection.

Children in forward-facing seats may outgrow the height of the shoulder harness slots before they exceed the weight limits, since the harness slots must be at or above the shoulders in a forward-facing configuration. In addition, most older vehicles can be retrofitted with anchors for use with an upper tether strap; parents should consult their vehicle owner's manuals for instructions on how to take advantage of this additional safety feature.

We disagree with Dr. Biagioli's recommendation against low-back boosters. While they are inappropriate for use in vehicles without headrests or high seatbacks, they are an excellent choice when the vehicle seat or headrest can offer the child head and neck protection in rear impacts. They also have the advantage of being less conspicuous than high-back boosters, which may be more acceptable to an older child. Their smaller size may allow installation of three child restraints in the rear seats of small vehicles, and facilitate use when carpooling. In addition, low-back boosters are usually inexpensive. However, shield boosters, which are somewhat similar in design to low-back boosters, are no longer recommended as acceptable child restraint systems.

Finally, we would like to recommend that children be evaluated for graduation to a vehicle seatbelt alone using the posture and belt fit guidelines of the SafetyBeltSafe five-step test described atwww.carseat.org. The height, weight, and age limits published by the National Highway Traffic Safety Administration³ are based on a limited number of vehicles and children, and are not absolute rules. A child may need a booster in a vehicle with a long seat cushion, but not in a vehicle with smaller seats where they can comfortably sit up straight and achieve good belt fit.

In reply: I would like to clarify two items from my article, “Proper Use of Child Safety Seats.”¹ In March 2002, the Committee on Injury and Poison Prevention for the American Academy of Pediatrics (AAP) changed their recommendation on how long to face a child's car seat rearward. The AAP policy statement still recommends that “children should face the rear of the vehicle until they are at least (one) year of age and weigh at least 20 (lb).”² This is consistent with my article¹; however, the updated policy also recommends that “if a car safety seat accommodates children rear facing to higher weights, for optimal protection, the child should remain rear facing until reaching the maximum weight for the car safety seat, as long as the top of the head is below the top of the seat back.”² Therefore, providers should recommend that parents check the limits of their seat and that a child face rearward as long as possible.

The article¹ states that “low-back boosters are not recommended,” but this information applies only to low-back shield boosters. There are other models of low-back boosters that employ the use of a lap and shoulder belt that are safe and inexpensive. To protect the head, back, and neck, providers should advise that low-back boosters only be used in an automobile seat that has a headrest and a shoulder-lap combination belt.