Effect of phototherapy on cardiorespiratory activity during sleep in neonates with physiologic jaundice.

BACKGROUND Phototherapy is considered the standard of care for neonatal jaundice. However, its short-term cardiorespiratory effects have not been studied thoroughly. OBJECTIVES To assess the cardiorespiratory effect of phototherapy during sleep in term infants with physiologicjaundice. METHODS We performed two polysomnography studies during 3 hours sleep in 10 healthy term infants with physiologic jaundice; each infant served as his/her own control. The first study was performed just prior to phototherapy and the second study during phototherapy 24 hours later. Heart and respiratory rates, type and duration of apneas, and arterial oxygen saturation were analyzed during active and quiet sleep. RESULTS Term infants (gestational age 38.6 +/- 1.4 weeks, birth weight 3.2 +/- 0.5 kg) underwent the two polysomnography studies within a short time interval and had a comparable bilrubin level (3.6 +/- 0.8 and 4.5 +/- 0.8 days; 14.5 +/- 1.4 and 13.8 +/- 2.1 mg/dl, P = NS, respectively). There was no difference in sleeping time or the fraction of active and quiet sleep before or during phototherapy. During active sleep under phototherapy there was a significant decrease in respiratory rate and increase in heart rate (54.3 +/- 10.3 vs. 49.1 +/- 10.8 breaths/minute, and 125.9 +/- 11.7 vs. 129.7 +/- 15.3 beats/minute, respectively, P < 0.05), as well as a decrease in respiratory effort in response to apnea. These effects were not found during quiet sleep. Phototherapy had no significant effect on oxygen saturation, apnea rate or periodic breathing in either sleep state. No clinical significant apnea or bradycardia occurred. CONCLUSIONS Phototherapy affected the cardiorespiratory activity during active sleep but not during quiet sleep in term infants with physiologic jaundice. These effects do not seem to have clinical significance in "real-life" conditions.