Feldman J M, Roth J V, Bjoraker D G
Department of Anesthesiology, Albert Einstein Medical Center, Philadelphia, Pennsylvania 19141.
Anesth Analg. 1995 Jan;80(1):108-13. doi: 10.1097/00000539-199501000-00019.
Acute normovolemic hemodilution (ANH) entails collecting blood from a patient immediately prior to surgery with concurrent fluid infusion to maintain intravascular volume constant. Blood collected during ANH is later reinfused to replace the red cell losses that occur during surgery. This technique is advocated as a means to reduce or eliminate homologous blood transfusion during surgery. Published guidelines for performing ANH vary, and the literature does not describe how to perform ANH to achieve the maximum benefit for a given patient. To evaluate how to save red blood cells as much as possible via ANH, and to determine the maximum benefit that can be expected, we developed a mathematic model of the process. Using the model, the net red cell mass savings possible when using ANH can be calculated given the patient's weight, initial hematocrit and minimum safe hematocrit. Results are reported to demonstrate the impact of the initial hematocrit and minimum safe hematocrit on the red cell savings possible with ANH. The data indicate that ANH does indeed save red blood cells that would otherwise be lost during surgery. However, the red cell savings possible when using ANH are not as much as typically published and, a degree of hemodilution more than that which is typically recommended is necessary to achieve even modest red cell savings.
急性等容血液稀释（ANH）是指在手术即将开始前采集患者血液，同时输注液体以维持血管内容量恒定。ANH过程中采集的血液随后回输，以补充手术期间发生的红细胞丢失。该技术被提倡作为减少或消除手术期间同种异体输血的一种方法。已发表的关于实施ANH的指南各不相同，且文献中未描述如何实施ANH才能使特定患者获得最大益处。为了评估如何通过ANH尽可能多地保存红细胞，并确定可预期的最大益处，我们建立了该过程的数学模型。利用该模型，给定患者的体重、初始血细胞比容和最低安全血细胞比容，就可以计算出使用ANH时可能节省的红细胞净量。报告结果以证明初始血细胞比容和最低安全血细胞比容对ANH可能节省红细胞的影响。数据表明，ANH确实能保存那些否则会在手术期间丢失的红细胞。然而，使用ANH时可能节省的红细胞量并不像通常公布的那么多，并且需要超过通常推荐程度的血液稀释才能实现哪怕是适度的红细胞节省。
