Changing mortality and causes of death in infants 23-27 weeks' gestationalage

Objective: To contrast the mortality rates and changes in the causes of dea th of very preterm infants (23-27 weeks): before and after the introduction of exogenous surfactant in 1991, and to identify any preventable causes of death remaining in the 1990s. Methodology: This was a cohort study on consecutive preterm infants of 23-2 7 weeks' gestational age born in the Royal Women's Hospital, Melbourne, a l evel III perinatal centre. The infants were livebirths free of lethal anoma lies from two distinct eras, 1983-90, and 1992-96, inclusive. The main outc ome measures were mortality during the primary hospitalization and the caus es of death before and after the introduction of exogenous surfactant in 19 91. Results: In 1983-90, 261 of 508 livebirths (51.4%) of 23-27 weeks' gestatio nal age died, a significantly higher proportion than the 109 of 384 (28.4%) livebirths who died in the period 1992-96. The mortality rate fell signifi cantly with increasing gestational age and was lower at each week of gestat ional age in 1992-96. More infants who died in 1992-96 were treated intensi vely in the neonatal intensive care unit (NICU). Of the group of infants wh o died or who were treated intensively in NICU, respiratory causes of death predominated. However, the causes of death changed over time. In 1992-96 p roportionally fewer infants died from respiratory causes (1983-90, 82.5%; 1 992-96, 60.0%; odds ratio (OR) 0.31, 95%; confidence interval (CI) 0.16-0.5 7), but more from septic causes (1983-90, 14.3%; 1992-96, 43.8%; OR 4.9, 95 %; CI 2.6-9.2). Conclusions: As the mortality rate has fallen over time, respiratory causes of death have diminished, but septic causes of death have increased. Furth er advances in the use of exogenous surfactant and respiratory support may reduce respiratory deaths. Effective strategies to reduce nosocomial infect ions are urgently required.