Template bleeding times of 240 neonates born at 24 to 41 weeks gestation

Abstract

The template bleeding time is a test used to assess the hemostatic effectiveness of platelet/endothelial interactions. A modified template bleeding time, described over 15 years ago by Andrew et al., has been used to test this aspect of hemostasis in term and preterm infants, but questions remain regarding the effect of gestational age and postnatal age on results. The effect of the platelet count (platelets per microliter blood) and the circulating platelet mass (nl platelets per microliter blood) on the bleeding time of neonatal intensive care unit (NICU) patients also require better definition. We measured template bleeding times on 240 neonates at Ospedale A Perrino, in Brindisi, Italy; studying groups of n=60 at the following gestational ages; <28 weeks, 29 to 32 weeks, 33 to 37 weeks and > or =38 weeks. In each group of 60 neonates, 20 were studied on the first day after birth, 20 were studied on day 10 and 20 were studied on day 30. A multivariate analysis was performed to examine various associations with bleeding time. Bleeding times, on the first day of life, were shorter as gestational age increased. Those born <33 weeks gestation had bleeding times about twice that of those > or =38 weeks (P<0.001). Bleeding times tended to shorten between days 1 and 10. Little or no further shortening occurred between days 10 and 30, and by day 30 they were not statistically different between the various gestational age groups. No independent effect on bleeding time could be ascribed to gender, platelet count or circulating platelet mass, but independent effects were found for hematocrit (P<0.02) and gestational age (P<0.001). On the first day of life, preterm neonates have a longer bleeding time than do term neonates. By day of life 10, the bleeding times at all gestational ages are shorter and are indistinguishable on the basis of gestational age at birth. Additionally, since platelet counts as low as 110 000 per microliter did not prolong the bleeding time, we see no benefit of administering a platelet transfusion to a stable, nonbleeding, NICU patient with mild thrombocytopenia (platelet count 100 000 to 150 000 per microliter).