Abstract 1877 Poster Session IV, Tuesday, 5/4 (poster 296)

ANS treatment is recommended to prevent Hyaline Membrane Disease (HMD) in preterm infants. However the potential pulmonary beneficial effects of ANS treatment and/or whether there is a dose dependent response in VLBW ≤1000g remain unclear. This is a relevant issue in preterm deliveries where full ANS dosing is not possible. At our institution Dexamethasone is administered q12h for a total of four doses in the event of preterm labor (≤34wks) and in the absence of maternal diabetes, infection, or pregnancy induced hypertension (PIH). The study objective was to determine the dose dependent effects of ANS on the outcome of VLBW infants ≤1000g. Adverse respiratory outcomes included HMD, surfactant treatment, and chronic lung disease (CLD) defined as oxygen requirement at 36 wks gestational age (GA). The incidence of intraventricular hemorrhage (IVH) and death is also reported. Between Jan 95 and Dec 97, 171 liveborn infants ≤1000g were delivered at Parkland memorial Hospital. Exclusion criteria included congenital anomalies (n=3), infants of mothers with PIH (n=31), SGA infants (n=5), and discordant twins (n=5). The remaining infants (n=127) were categorized into three groups based on the steroid doses received prior to delivery: Group I (n=49, 39%) received no steroids, Group II (n=31, 24%) received 1 or 2 doses, and Group III (n=47, 37%) received 3 or 4 doses. Data were assessed by Chi-square analysis, and ANOVA as indicated. Results: The three groups (I vs II vs III) were comparable with regard to mean BW (785, 835, 805gms), median GA (26.1, 26.3, 26.3wks), Male (51%, 64%, 53%), C/S delivery (57%, 45%, 51%), cord pH (median 7.30, 7.29, 7.30), 5 min Apgar score (median 6, 7, 7), twins (10%, 16%, 11%), and chorioamnionitis (6%, 10%, 21%, p=0.07). HMD was less in infants in group III vs I (38%, 58%, 78%, p<0.001), as was surfactant requirement (34%, 64%, 69%, p<0.002). However, there were no difference in the incidence of CLD (48%, 53%, 60%, p=0.6) and CLD or death (55%, 61%, 76%, p=0.12), though death occurred less frequently in the steroid treated infants (13%, 16%, 39%, p=0.01). Any IVH (23%, 54%, 55%, p<0.005), and severe IVH (11%, 26%, 37%, p<0.005) also occurred less in group III vs II vs I. These data indicate: 1) VLBW ≤1000g who receive a complete course of ANS exhibit less HMD and are less likely to be administered surfactant than infants exposed to lesser or no ANS. 2) No difference in the evolution of CLD was noted among the three groups. This finding cannot be attributed to the increased mortality noted in the less exposed infants though this may reflect sampling size. 3) Similarly, a full course of ANS is necessary for a decrease in any and severe IVH.