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

Abstract

Objective: 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.Study Design: We measured template bleeding times on 240 neonates at Ospedale A Perrino, in Brindisi, Italy; studying groups of n ¼ 60 at the following gestational ages; <28 weeks, 29 to 32 weeks, 33 to 37 weeks and X38 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.Result: 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 X38 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). Conclusion: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).

Ibuprofen lysine administration to neonates with a patent ductus arteriosus: effect on platelet plug formation assessed by in vivo and in vitro measurements

“…Hemorrhagic complications among ELBW neonates can be significant and therefore medications that do not impair platelet function might be considered preferentially above alternative medications that do. 17,20 In this study we assessed platelet plug formation of 20 NICU patients where ibuprofen dosing had been ordered by the clinician in order to close a PDA. We assessed platelet plug formation using two tests: the template bleeding time and the PFA-100 closure time.…”

“…22 However, the volume of blood required for aggregometry precludes application to neonates, and therefore the tests we selected are the best we are aware of for this population. 17 Third, operator variability reduces the reproducibility of the bleeding time, but we limited our technicians to only two (MJS and RDC). Indeed, the range in bleeding times we obtained was not more than the range in PFA-100 times.…”

“…17 Patients were considered ineligible if they had petechiae, mucocutaneous bleeding, bleeding into an endotracheal tube or gastrointestinal bleeding. A cranial ultrasound examination was not required before study entry.…”

“…16 A template bleeding time was performed (by MJS or RDC) using methods previously described. [2][3][4]10,13,17 Briefly, a blood-pressure cuff appropriate for the infant's size was placed on an upper extremity and set at a pressure equal to the last measured mean blood pressure. If no mean blood pressure had been recorded in the previous 6 h, the pressure was set at 20 mm Hg for those with a weight <1 kg, at 25 mm Hg for those weighing 1 to 2 kg, and at 30 mm Hg for those weighing >2 kg.…”

“…The capacity to generate a hemostatically effective platelet plug can be assessed by in vivo methods (template bleeding time) and by in vitro methods (platelet function analyzer (PFA)-100 time). [2][3][4][10][11][12][13][14][15][16][17] We obtained these tests before and at various preset intervals after ibuprofen administration to 20 neonatal intensive care unit (NICU) patients who had a PDA and herein report the results of those studies.…”