Pleasant smell may reduce apnea in preemies

Premature newborns have a heightened risk of sleep apnea - brief periods when they stop breathing - but pumping a pleasant odor into their incubators seems to reduce the frequency of such spells, a study from France suggests.

More effective treatments are needed for the common problem of recurrent apnea among premature babies, Dr. Luc Marlier from Centre Hospitalier Regional Universitaire de Hautepierre in Strasbourg note in the medical journal Pediatrics.

In a previous study that examined the ability of preterm infants to detect and discriminate between different odors, Dr. Marlier's team observed that pleasant odors led to an increase in their breathing rate, particularly during active sleep.

With the current study, the researchers attempted to verify "whether the stimulating effect of a pleasant odor could counterbalance (at least partly) the respiratory fall observed during apneic spells."

Over a 24-hour period, the investigators diffused a pleasant odor (vanillin) into the incubators of 14 infants born at 24 to 28 weeks into pregnancy who had recurrent apnea despite medical therapy.

Overall, odor therapy led to a 36 percent reduction in the rate of apneas in 12 of the infants. The average number of apnea episodes rose again when the odor therapy was stopped.

There did not appear to be any adverse effects from odor therapy. Daily respiratory rates and heart rates appeared to remain stable regardless of whether the infant was exposed to odor.

Marlier's team adds that they "cannot fully explain the efficacy of vanillin in these cases." Nonetheless, it appears from this study that the introduction of a pleasant odor in the incubator is helpful to these infants and should be explored further, they conclude.

SOURCE: Pediatrics, January 1, 2005.