Intermountain Healthcare, McKay-Dee Hospital Center, Ogden, UT 84403, USA.
J Perinatol. 2011 Jul;31(7):477-80. doi: 10.1038/jp.2010.154. Epub 2011 Mar 3.
On the day of birth, the bleeding time of very low birth-weight (VLBW, <1500 g) neonates is generally prolonged, compared with term neonates. However, their bleeding time generally improves (shortens) over the next 7 to 10 days. Ampicillin can prolong the bleeding times of term and late preterm neonates, but its effect on VLBW neonates, who already have a somewhat prolonged bleeding time initially, is not known.
This was a prospective, single-centered, paired, before vs after test of the effect of ampicillin on template bleeding time and PFA-100 time (platelet function analyzer). Ampicillin was dosed at every 12 h intravenously, but decisions about discontinuation were made by the responsible clinician, independent of this study.
A total of 20 VLBW neonates were studied. They ranged from 23- to 30-weeks gestation at birth and weighed 500 t 1410 g. Initial bleeding times averaged 166 s (95% CI, 138 to 194) and initial PFA-100 times averaged 119 s (95% CI, 90 to 148). In all, 10 had ampicillin dosing stopped after a shorter course (4 to 7 doses) and 10 had it continued for a longer course (10 to 15 doses). Blood cultures were sterile in all 20, and no differences in laboratory or clinical features were found between those treated with a shorter vs longer course. After stopping the ampicillin following a short course the bleeding times and PFA-100 times were similar to the initial values. However, after a longer course the bleeding times were prolonged by an average of 2 min, to 284 s (95% CI, 242 to 326; P=0.001 vs initial). The PFA-100 times also trended longer by an average of 44 s (P=0.07). The number of doses of ampicillin received in the first week correlated with the degree of prolongation in bleeding time (r=0.68).
Over the first week of life, a period when the bleeding time of VLBW neonates normally shortens, the opposite occurred (the bleeding time lengthened) if ≥ 10 doses of ampicillin were administered.
极低出生体重儿（VLBW，<1500g）的出生日出血时间通常较足月新生儿延长。然而，他们的出血时间通常在接下来的 7 到 10 天内改善（缩短）。氨苄西林可延长足月和晚期早产儿的出血时间，但对于最初出血时间已有一定延长的 VLBW 新生儿，其效果尚不清楚。
这是一项前瞻性、单中心、配对、前后测试氨苄西林对模板出血时间和 PFA-100 时间（血小板功能分析仪）的影响。氨苄西林每 12 小时静脉注射一次，但停药决定由负责的临床医生根据本研究之外的情况做出。
共研究了 20 名 VLBW 新生儿。他们出生时胎龄为 23 至 30 周，体重为 500 至 1410g。初始出血时间平均为 166 秒（95%CI，138 至 194），初始 PFA-100 时间平均为 119 秒（95%CI，90 至 148）。共有 10 名患儿在较短疗程（4 至 7 剂）后停止氨苄西林治疗，10 名患儿继续较长疗程（10 至 15 剂）。所有 20 名患儿的血培养均为无菌，接受较短疗程和较长疗程治疗的患儿在实验室和临床特征方面无差异。在较短疗程后停止氨苄西林治疗后，出血时间和 PFA-100 时间与初始值相似。然而，在较长疗程后，出血时间平均延长 2 分钟，达到 284 秒（95%CI，242 至 326；与初始值相比，P=0.001）。PFA-100 时间也平均延长了 44 秒（P=0.07）。在第一周内接受的氨苄西林剂量数与出血时间的延长程度相关（r=0.68）。
在 VLBW 新生儿出血时间正常缩短的生命第一周内，如果给予≥10 剂氨苄西林，则会发生相反的情况（出血时间延长）。
