Background: Following the introduction of the DRG system and the definition of structural requirements for neonatal intensive care units (NICUs) in Germany, the number of perinatal centres has increased dramatically. The question arises if the formation of a great number of small NICUs compromises the outcome of infants with less than 1 500 g birthweight (VLBW).
Material and methods: A systematic medline search was performed for publications on patient volume in relation to outcome of VLBW infants. Mortality and intraventricular hemorrhage were used as outcome criteria. 9 publications from North America, 7 from non-German Europe and 5 from Germany were found. In 18 studies odds ratios and 95 % confidence intervals were reported for volume-outcome relations.
Results: For VLBW infants, mortality and intraventricular hemorrhage rates varied greatly between hospitals. In 20 of 21 publications, results were significantly less favourable in smaller hospitals. The threshold for obstetrics was 500-1000 deliveries per year and for neonatology 35-50 VLBW admissions per year. No significant relation of volume and outcome was found above 50 VLBW infants per year.
Discussion: The requirement of a minimum patient volume is a necessary, but not the only condition for good results in VLBW infants.
Conclusions: In addition to fulfilling formal structural requirements, perinatal centres should be established in large delivery hospitals with at least 35 to 50 VLBW admissions per year.