Abstract 1734

Hyperbilirubinemia is the most common problem during the neonatal period and phototherapy is the most prevalent therapeutic modality. However the influence of phototherapy on cardio-respiratory activity during sleep has not yet been studied.

Methods: Ten healthy full term infants (GA 38.6±1.4 wk., 3.2 ±0.5 kg., Apgar score at 5 min. 8.8±0.3) with physiological hyperbilirubinemia (13.8±2.1 mg%) underwent two subsequent polysomnographic tests of three hours each at 3.6±0.6 and 4.5±0.8 days of life respectively. Each infant served as his own control. The first test (control) was performed shortly after the diagnosis of jaundice was made and just before phototherapy was started. The second test (study) was done 22±4 hrs. later, during phototherapy. The study test was done only if serum bilirubin level was not significantly different from the pre-phototherapy bilirubin concentration (14.5 ±1.4 and 13.8±2.1 mg% respectively, NS). Periods of active and quiet sleep, heart and respiratory rate and episodes of central and obstructive apnea were analyzed in each of the test periods. Comparisons were made for each of these parameters before and during phototherapy. (paired t test)

Results: During active sleep phototherapy was associated with a significant decrease in respiratory rate from 54±1 BPM to 49±1 BPM, P<0.05 and with a concurrent increase in heart rate from 125± 3 BPM to 132± 3 BPM, P< 0.05). In contrast, during quiet sleep, no change was observed in either heart or respiratory rate. Both number and duration of apneic episodes (>3 seconds) were significantly higher under phototherapy and occurred only during active sleep (P<0.05). Apneic episodes were all self-limited and were associated with a transient acceleration in heart rate during those events. Phototherapy did not cause any change in either the number or severity of apneic episodes during quiet sleep and nor in the ratio of active to quiet sleep. From these data we conclude that although phototherapy can affect cardio-respiratory activity during active sleep, these effects are mild and probably not clinically significant in most cases.