Olfactory stimulation prevents apnea in premature newborns

Methylxanthines and doxapram are currently used to treat apnea of prematurity but are not fully effective and often present undesirable side effects. The present study examines whether exposure to an odor known to modulate the infant's respiratory rate could reduce the frequency of apneic spells.

Fourteen preterm newborns born at 24 to 28 gestational weeks presenting recurrent apnea despite caffeine and doxapram therapy were exposed to a pleasant odor diffused during 24 hours in the incubator. Efficiency of the olfactory treatment was judged by comparing frequency and severity of apneas occurring during the day of odorization with that observed the day before (baseline) and the day after (posttreatment control). Apnea was defined as any complete cessation of breathing movements for >20 seconds, or less if associated with hypoxia or bradycardia.

Concerning all types of apneas, a diminution of 36% was observed and seen in 12 of 14 infants. Apneas without bradycardia were reduced (44%) during the day with odorization, and this diminution affected all the infants. The frequency of apnea with moderate bradycardia (heart rate between 70 and 90 beats per minute) was maintained while the frequency of apnea associated with severe bradycardia (heart rate <70 beats per minute) decreased strongly (45%) and affected all the infants. No side effects were observed.

The introduction of a pleasant odor in the incubator is of therapeutic value in the treatment of apneas unresponsive to caffeine and doxapram.