D'Errico C, Shayevitz J R, Martindale S J
Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, USA.
J Cardiothorac Vasc Anesth. 1996 Jun;10(4):451-7. doi: 10.1016/s1053-0770(05)80003-5.
The present study was conducted to determine how children and adults differ (it at all) with respect to sensitivity to heparin activity and heparin-protamine interactions during cardiac surgery requiring cardiopulmonary bypass (CPB).
A prospective study of both children and adults undergoing CPB.
A tertiary care academic medical center between July 1992 and October 1994.
Ninety patients who had cardiac or aortic arch surgery using CPB. The median age of the entire study sample was 15.8 years (range 2 months to 72 years).
Data were obtained using the Medtronic Hemotec Hepcon Hemostasis Management System (Englewood, CO). An ex vivo heparin dose-response (HDR) curve was generated for each patient before skin incision to determine the target heparin concentration (THC) needed to achieve an activated coagulation time (ACT) of at least 480 seconds. Protamine dose was determined on the basis of whole blood heparin concentration estimated by means of a heparin-protamine titration.
The study population was divided into four groups based on age: infants (< 1 year), preschool (1 to 5 years), school-age (5 to 14 years) and adults (> 14 years). The mean +/- SD THC for the preschool group was 4.0 +/- 1.1; for infants, 3.3 +/- 0.7; for school-age, 3.1 +/- 0.7; and for adults, 3.4 +/- 0.7. The initial dose of heparin needed to achieve this THC (mean +/- SD) was significantly higher in infants (578 +/- 220 U/kg) and preschool children (477 +/- 159 U/kg) than in school-age children (327 +/- 57 U/kg) and adults (332 +/- 64 U/kg). The ratio of protamine to heparin was significantly higher in adults (1.4 +/- 0.5) and school-age children (1.3 +/- 0.6) than in infants (1.1 +/- 0.7) and preschool children (1.1 +/- 0.4).
Pre-school children are less sensitive to heparin but also display a wider range of sensitivity. The data in this study support the use of 300 U/kg of heparin before CPB in patients > or = 5 years but suggest that heparin requirements may be greater in the younger patient who may require as much as 500 U/kg to achieve what is believed to be an appropriate target heparin concentration for initiating CPB.
本研究旨在确定在需要体外循环（CPB）的心脏手术期间，儿童和成人在肝素活性敏感性及肝素-鱼精蛋白相互作用方面（若存在差异的话）有何不同。
对接受CPB的儿童和成人进行的前瞻性研究。
1992年7月至1994年10月期间的一家三级医疗学术医学中心。
90例接受CPB心脏或主动脉弓手术的患者。整个研究样本的中位年龄为15.8岁（范围2个月至72岁）。
使用美敦力Hemotec Hepcon止血管理系统（科罗拉多州恩格尔伍德）获取数据。在皮肤切开前为每位患者绘制体外肝素剂量-反应（HDR）曲线，以确定达到至少480秒活化凝血时间（ACT）所需的目标肝素浓度（THC）。根据通过肝素-鱼精蛋白滴定估算的全血肝素浓度确定鱼精蛋白剂量。
根据年龄将研究人群分为四组：婴儿（<1岁）、学龄前儿童（1至5岁）、学龄儿童（5至14岁）和成人（>14岁）。学龄前儿童组的平均±标准差THC为4.0±1.1；婴儿组为3.3±0.7；学龄儿童组为3.1±0.7；成人组为3.4±0.7。达到该THC所需的初始肝素剂量（平均±标准差）在婴儿（578±220 U/kg）和学龄前儿童（477±159 U/kg）中显著高于学龄儿童（327±57 U/kg）和成人（332±64 U/kg）。成人（1.4±0.5）和学龄儿童（1.3±0.6）的鱼精蛋白与肝素的比例显著高于婴儿（1.1±0.7）和学龄前儿童（1.1±0.4）。
学龄前儿童对肝素的敏感性较低，但敏感性范围也更广。本研究数据支持≥5岁患者在CPB前使用300 U/kg肝素，但表明年龄较小的患者肝素需求量可能更大，可能需要高达500 U/kg才能达到被认为启动CPB合适的目标肝素浓度。
