43 OUTCOME TRENDS OF INFANTS WEIGHING LESS THAN 800 GRAMS AT BIRTH

Advancing neonatal technology and the refining expertise in perinatal and NICU management have led to the improved survival of extremely low birth weight infants (ELBW). In four separate reports, we have examined the outcome of infants born weighting less than 800 g admitted to the University of Washington NICU in Seattle. In these studies, mortality declined from 80% (1977-1980) to 64% (1983-1985) to 50% (1986-1990) and 53% (1991-1995) with no significant difference in the prevalence of major neurosensory disabilities in survivors. In this fifth cohort (1996-2000) we further examine the mortality and morbidity of this unique population and describe ELBW outcome trends over a near 25-year period. From 1996 to 2000, a total of 200 newborns weighing less than 800 g were admitted to the University of Washington NICU, compared with 208 (1991-1995), 206 (1986-1990), 128 (1983-1985), and 95 (1977-1980). One hundred ten (55%) survived to discharge compared with 97(47%) (1990-1995), 104 (50%) (1986-1990); 46 (36%) (1983-1985), and 18 (20%) (1977-1980). Mean birth weight of the survivors was 689 g (484-799) compared with 705 g (499-798) (1990-1995), 695 g (457-799) (1986-1990), 706 g (540-790) (1983-1985), and 730 g (595-780) (1977-1980). Mean gestational age of our current cohort was 25 weeks (23-31), which is comparable to the four previous cohorts. Seventy-seven of 110 (70%) of the surviving infants in our current cohort were followed longitudinally monitoring growth, vision and hearing, neurologic status, and developmental function. The mean corrected age at follow-up was 30 months (12-72). Major neurosensory disabilities were identified in 16/76 (21%), which is not significantly different from 11/74 (15%) (1991-1995), 17/72( 23%) (1986-1990), 8/38 (21%) (1983-1985), and 3/19(19%) (1977-1980). Over the past 25 years, the survival of our ELBW infants has improved from 20 to 55%. This improved survival has occurred without an increase in the prevalence of major neurosensory disabilities.