Kick O, Daniel E
Department of Anesthesia and Surgical Intensive Care, University Hospital, Nantes, France.
Transfusion. 1997 Feb;37(2):141-3. doi: 10.1046/j.1537-2995.1997.37297203515.x.
Acute normovolemic hemodilution (ANH) is recommended as a simple and cost-effective method of autologous transfusion. The present mathematical model, based on the current clinical practice of removing 2 to 3 units of fresh whole blood, defines the indications for ANH.
A mathematical model and subsequent nomograms were developed to define patients for whom removal of 2 to 3 units (450 mL each) would allow a theoretical red cell savings equivalent to 1 unit of packed red cells (volume, 250 mL; hematocrit, 60%), that is, a successful application of the technique. Minimal safe target hematocrits were defined as 30, 26, and 22 percent.
The minimal initial hematocrits required for given patient weights are displayed on nomograms derived from the mathematical model. The nomograms also indicate the surgical blood loss allowed without ANH: for example, a 75-kg man, (2-unit ANH, minimal safe hematocrit 22%) requires a minimal initial hematocrit of 42 percent (surgical blood loss of 0.64 x estimated blood volume = 3100 mL).
ANH involving the removal of 2 to 3 units (450 mL each) may be useful in patients with anticipated blood loss exceeding 50 percent of estimated blood volume, high initial hematocrit, and a capacity to tolerate dilution-induced anemia.
急性等容血液稀释（ANH）被推荐为一种简单且具成本效益的自体输血方法。当前的数学模型基于目前去除2至3单位新鲜全血的临床实践，确定了ANH的适应证。
开发了一个数学模型及后续的列线图，以确定去除2至3单位（每单位450毫升）血液能在理论上节省相当于1单位浓缩红细胞（体积250毫升；血细胞比容60%）的红细胞的患者，即该技术的成功应用。将最低安全目标血细胞比容定义为30%、26%和22%。
根据数学模型得出的列线图显示了特定患者体重所需的最低初始血细胞比容。列线图还表明了在不进行ANH的情况下允许的手术失血量：例如，一名75千克的男性（2单位ANH，最低安全血细胞比容22%）需要最低初始血细胞比容为42%（手术失血量为0.64×估计血容量 = 3100毫升）。
对于预计失血量超过估计血容量50%、初始血细胞比容高且能够耐受稀释性贫血的患者，去除2至3单位（每单位450毫升）血液的ANH可能有用。
