Acute Normovolemic Hemodilution (ANH) is a valuable method of perioperative blood conservation for those patients who are not good candidates for donor transfusion, autologous pre-donation, or autotransfusion. Surgical oncology patients can benefit greatly from ANH.
ANH is performed under specifically approved protocols. ANH is initiated by an Anesthesiologist, Nurse or Phlebotomist by drawing off a predetermined amount of whole blood from the surgical patient immediately before or at the beginning of surgery. ANH blood contains red blood cells, plasma, platelets and other clotting factors that assist in hemostasis, along with a small amount of anticoagulant.
The patient’s blood is appropriately labelled, and all ANH units are numbered and stored at room temperature in the Operating Room at the patient’s side until the end of surgery. Based upon a number of factors, as the patient’s blood is drawn it is simultaneously replaced with either colloids or crystalloids, at a specific ratio of ANH blood to replacement fluid. At the end of the surgical procedure, when active bleeding has ceased, the units of ANH blood are transfused back into the patient.
By drawing, preserving and re-transfusing the patient’s own blood at the beginning of the procedure, net blood loss is reduced, because the blood that may be lost during surgery was diluted by the replacement fluids.