Kreimeier U, Messmer K
Department of Anesthesiology, Ludwig-Maximilians-University Munich, Klinikum Grosshadern, Marchioninistrasse 15, D-81377 Munich, Germany.
World J Surg. 1996 Nov-Dec;20(9):1208-17. doi: 10.1007/s002689900184.
Acute normovolemic hemodilution entails removal of blood from a patient either immediately before or shortly after induction of anesthesia and simultaneous replacement with cell-free fluid. Nowadays, because of their predictable volume effects, the synthetic colloids (6% dextran 60/70, 6% hydroxyethyl starch 200,000) are preferred as volume substitutes; albumin should be avoided because of its high cost. Hemodilution has experienced a renaissance in recent years, mainly due to the evolving discussion of legal aspects, immunologic changes, viral infections, and a potentially higher cancer recurrence rate associated with the transfusion of homologous blood. Hemodilution should be considered for elective surgical patients free of contraindications and presenting with an initial hemoglobin concentration >/= 12 g/dl and an anticipated blood loss of >/= 1500 ml. The efficacy of this method (judged by the need to give homologous blood transfusion) depends on the preoperative (initial) hematocrit, the target hematocrit (to which hemodilution is performed), and the preset intra- and postoperative transfusion trigger. In the past, data from clinical trials showed that in healthy subjects a target hematocrit of 20% to 25% (hemoglobin 7.0-8. 0 g/dl) is feasible and safe for the patient. The lower the target hematocrit accepted, the more extensive is the monitoring required: Intraoperative target hemoglobin concentrations of 5.0 g/dl and less have been tolerated by surgical patients without adverse effects. The safety and efficacy of acute normovolemic hemodilution in terms of reducing homologous blood transfusion requirements has been demonstrated in various clinical studies. Hemodilution therefore is regarded an integral part of programs aimed at reducing the need for homologous blood and can thus be successfully combined with preoperative autologous blood deposition, intraoperative blood salvage, and carefully adjusted surgical techniques. Hemodilution is feasible and relatively cost-effective, and it minimizes adverse effects associated with transfusion of homologous blood, particularly transmission of viral diseases, immunosuppression, and infectious complications.
急性等容血液稀释是指在麻醉诱导前即刻或诱导后不久从患者体内采集血液，并同时用无细胞液体进行置换。如今，由于其容量效应可预测，合成胶体（6% 右旋糖酐 60/70、6% 羟乙基淀粉 200,000）更适合作为容量替代物；由于成本高昂，应避免使用白蛋白。近年来，血液稀释再度兴起，主要是因为法律方面、免疫变化、病毒感染以及与输注同源血相关的潜在更高癌症复发率等方面的讨论不断发展。对于无禁忌证、初始血红蛋白浓度≥12 g/dl 且预计失血量≥1500 ml 的择期手术患者，应考虑进行血液稀释。该方法的疗效（通过是否需要输注同源血来判断）取决于术前（初始）血细胞比容、目标血细胞比容（进行血液稀释所达到的水平）以及预设的术中和术后输血触发点。过去，临床试验数据表明，对于健康受试者，目标血细胞比容为 20% 至 25%（血红蛋白 7.0 - 8.0 g/dl）对患者而言是可行且安全的。接受的目标血细胞比容越低，所需的监测就越广泛：手术患者术中目标血红蛋白浓度低至 5.0 g/dl 及更低时，也能耐受且无不良影响。各种临床研究已证实急性等容血液稀释在减少同源血输注需求方面的安全性和有效性。因此，血液稀释被视为旨在减少对同源血需求的方案的一个组成部分，从而可以成功地与术前自体血储存、术中血液回收以及精心调整的手术技术相结合。血液稀释是可行的且相对具有成本效益，它能将与输注同源血相关的不良影响降至最低，尤其是病毒疾病传播、免疫抑制和感染并发症。
