Acute Normovolemic Hemodilution: A Practical Approach

Abstract

Justifications: Perioperative allogeneic blood transfusion can be reduced or even completely avoided by using a set of different strategies: meticulous hemostasis, the use of pharmaceutical agents that assist in the process of coagulation/ fibrinolysis, the use of blood substitutes, induced hypotension, preoperative autologous blood donation, collection and reinfusion of autologous blood during the operation, as well as from acute normovolemic hemodilution (ANH). Contents: ANH consists of taking a percentage of the patient's blood volume and a concurrent infusion of acellular fluids in order to maintain normovolemia. As a consequence, a hemodiluted patient will lose less blood cells for each blood volume that is lost during the surgical procedure. The aim of this study is to clarify doubts and provide practical information relative to the procedure of ANH through the author's own experiences as well as literary examples. Conclusions: ANH is an easy and cheap technique performed during the intraoperative period useful to reduce the use of hemoderivatives.

Blood Transfusion Strategies in Elective Vascular Surgery

“…More than 250 papers have been published which assess ANH 21 . The chief aim of the ANH technique is to avoid or reduce the need for the transfusion of allogeneic blood during the perioperative period, [20,21] moreover, ANH can also extend the allowable fractional surgical blood loss before erythrocyte transfusion is required (the Weiskopf study) [22] and, in contrast to cell salvage (RBC washing device), thrombocytes and coagulation factors are available for transfusion as a part of autotransfusion. Another benefit of this procedure is the improvement in blood fluidity, which results in an increase in venous return and a reduction in the left ventricular afterload; both lead to an increase in cardiac output, mainly through the rise in stroke volume, but also to some increase in heart rate.…”

“…As described above, the maintenance of tissue oxygenation during ANH results from an increase in cardiac output and oxygen extraction [27]. Moreover, ANH is inexpensive; it is the cheapest strategy and the most cost effective among all the options [20].…”

Utility of acute normovolemic hemodilution in major surgeries in rural area: A prospective comparative study from North India

“…Acute normovolemic hemodilution (ANH) has been sed for the past many years, and its aim is to reduce or even avoid the need for transfusion of homologous blood during the perioperative period. [ 1 ] There are many major surgeries in general surgery, orthopedic head and neck surgeries where we expect major blood loss during operation. [ 1 2 3 ]…”

“…[ 1 ] There are many major surgeries in general surgery, orthopedic head and neck surgeries where we expect major blood loss during operation. [ 1 2 3 ]…”

A reply

“…A much larger volume of crystalloid solution is needed to achieve normovolaemia (about three times) than HES, because the crystalloid is redistributed into the interstitial spaces . An in‐vitro serial haemodilution study with crystalloid solution and HES in a balanced salt solution reported a biphasic response, with a lower degree of haemodilution (20–40%) causing enhanced coagulation, and a higher degree of haemodilution (> 40%) causing a decrease in the coagulation pattern .…”