Abstract

Objective: To characterize the survival and its related factors in extremely low birth weight infants (ELBW). Methods: Cohort of 93 premature infants weighing <1000g admitted at the NICU of the Clinical Regional Hospital from Valdivia, Chile, between 2000 and 2005, and followed until the discharge. Survival was estimated using Kaplan-Meier method, evaluating its relation with birth weight (BW), gestational age (GA), relation BW-GA, Apgar score, antenatal corticosteroid administration (ANC) and surfactant administration, comparing survival curves through Log-Rank test. Results: Overall survival was 64.5%, varying by BWfrom 33% (<600g) to 87% (900-999g), and by GA from null survival (<24 weeks) to 100% (>30 weeks). Deaths occurred mainly in neonatal period (97%), highlighting pulmonary hemorrhage (21.2%), hyaline membrane disease (18.2%) and extreme prematurity (18.2%) as the most important causes of death. Higher survival probability with greater BW and GA was found, detecting significant differences when comparing the groups of 800-899g versus 900-999g and between <25 weeks of gestation and 25-26 weeks. The use of ANC was significantly associated with better survival, but the number of doses administered was not related with the survival. Also, the best Apgar score at the minute and five minutes were associated with better survival. In overall analyses or by categories of BW and GA, gender, surfactant administration, and the condition of small for GA, were not associated with the survival. Conclusions: Nowadays, survival of Chilean ELBW infants begins in 24 weeks improving with greater GA. Consequently, strategies are required to avoid the premature birth or to extend the opportunity of the delivery in cases of maternal-fetal risk.