Surfactant therapy has improved survival rates for <1 kg birth weight. Its effect on the spectrum of BPD is unclear. Differences in BPD definition have rendered epidemiologic analysis difficult. Therefore, we analyzed our BPD experience in the post-surfactant era. We retrospectively reviewed 488 hospital records of infants less than 2000 gm birth weights admitted to the NICU between 1988--91 and 1992--94 inclusive. Many clinical and laboratory variables, including maternal betamethasone therapy, O2 requirements, BPD incidence and survival rates were compared for two periods in two weight groups. BPD was defined in two ways: BPD #1 = O2 dependency at day 28; and BPD #2 = O2 dependency at 36 weeks of conceptional age. Results: In <1 kg infnats during 1988--91 (n=46), the mean(+SD) duration of O2 therapy was 73 + 46 days, and the median 75 days; and during 1992--94 (n=97) they were 65 ± 43 days, and the median 63 days. In > 1 kg infants during 1988--91 (n=154), the mean duration of O2 therapy was 12 ± 24, and the median 3 days; and during 1992--94 (n=191), they were 20 ± 28 days, and the median 6 days. Other data are in the table (vent = ventilation, Mat-B=maternal betamethasone; * = median values).

Table 1
Full size table

Summary and Conclusions: In infants > 1 kg, the BPD spectrum did not reveal a clear trend. Mat-B frequency increased; median vent. days were equal, or lower; yet, BPD incidence (per both definitions) increased. In<1 kg infants, despite decreased mortality (15% vs 13%), the median vent. days dropped (by 8.5 days); median O2 therapy duration dropped (by 12 days); and BPD incidence remained the same (per definition #1) or dropped (per definition #2). Some of these changes can be due to a 26% increase in Mat-B use (in <1 kg) during 92--94. These trends need continuous monitoring.