Surgical blood conservation: Intraoperative hemodilution
- Michael Avidan, MD
Michael Avidan, MD
- Section Editor — Surgical Critical Care; Trauma Anesthesia
- Professor of Anesthesiology and Surgery
- Washington University School of Medicine
- Arthur J Silvergleid, MD
Arthur J Silvergleid, MD
- Section Editor — Transfusion Medicine
- Affiliate Associate Professor, Department of Pathology and Cell Biology
- University of South Florida, College of Medicine
- Medical Director, OneBlood, Inc.
- Section Editors
- Steven Kleinman, MD
Steven Kleinman, MD
- Section Editor — Transfusion Medicine
- Clinical Professor of Pathology
- University of British Columbia, Vancouver
- Roberta Hines, MD
Roberta Hines, MD
- Editor-in-Chief — Anesthesiology
- Section Editor — Anesthesia with Comorbid Cardiovascular/Pulmonary Conditions
- Professor and Chair, Department of Anesthesiology
- Yale School of Medicine
Acute normovolemic hemodilution (ANH) is a blood conservation technique that entails the removal of blood from a patient shortly after induction of anesthesia, with maintenance of normovolemia using crystalloid and/or colloid replacement. The amount of blood removed varies between one and three units (450 to 500 mL constitutes one unit), although larger volumes may be withdrawn safely in certain circumstances. The blood is infused into the patient during or shortly after the surgical procedure.
ANH can be used as the sole blood conservation technique, or it can be combined with preoperative autologous donation (see "Surgical blood conservation: Preoperative autologous blood donation"), blood salvage (see "Surgical blood conservation: Blood salvage"), or both.
Whether ANH is effective in decreasing allogeneic blood transfusion is debatable, and outcome benefits have not been clearly demonstrated. (See 'Advantages and disadvantages' below.)
Acute normovolemic hemodilution (ANH) can be considered for patients with normal initial hemoglobin (Hgb) levels who are expected to lose more than two units of blood (900 to 1000 mL) during surgery. It is safest when used in healthy, young adults, but can be used in other populations. It is a good option for Jehovah's Witnesses who will consent to ANH if the blood is maintained in a closed circuit continuous flow system . (See "The approach to the patient who refuses blood transfusion".)
In patients with a normal or high initial Hgb levels who are undergoing cardiac surgery, decreased blood viscosity associated with the induced anemia may have cardioprotective effects [2,3].
- Schaller RT Jr, Schaller J, Morgan A, Furman EB. Hemodilution anesthesia: a valuable aid to major cancer surgery in children. Am J Surg 1983; 146:79.
- Licker M, Ellenberger C, Sierra J, et al. Cardioprotective effects of acute normovolemic hemodilution in patients undergoing coronary artery bypass surgery. Chest 2005; 128:838.
- Licker M, Sierra J, Kalangos A, et al. Cardioprotective effects of acute normovolemic hemodilution in patients with severe aortic stenosis undergoing valve replacement. Transfusion 2007; 47:341.
- Feldschuh J, Enson Y. Prediction of the normal blood volume. Relation of blood volume to body habitus. Circulation 1977; 56:605.
- Lemmens HJ, Bernstein DP, Brodsky JB. Estimating blood volume in obese and morbidly obese patients. Obes Surg 2006; 16:773.
- Davy KP, Seals DR. Total blood volume in healthy young and older men. J Appl Physiol (1985) 1994; 76:2059.
- Jacob M, Bruegger D, Conzen P, et al. Development and validation of a mathematical algorithm for quantifying preoperative blood volume by means of the decrease in hematocrit resulting from acute normovolemic hemodilution. Transfusion 2005; 45:562.
- Weiskopf RB. Mathematical analysis of isovolemic hemodilution indicates that it can decrease the need for allogeneic blood transfusion. Transfusion 1995; 35:37.
- AABB. Standards for Perioperative Autologous Blood Collection and Administration, 5th ed, 2013.
- Carless PA, Henry DA, Moxey AJ, et al. Cell salvage for minimising perioperative allogeneic blood transfusion. Cochrane Database Syst Rev 2006; :CD001888.
- Curley GF, Shehata N, Mazer CD, et al. Transfusion triggers for guiding RBC transfusion for cardiovascular surgery: a systematic review and meta-analysis*. Crit Care Med 2014; 42:2611.
- Carson JL, Carless PA, Hebert PC. Transfusion thresholds and other strategies for guiding allogeneic red blood cell transfusion. Cochrane Database Syst Rev 2012; 4:CD002042.
- Carson JL, Terrin ML, Noveck H, et al. Liberal or restrictive transfusion in high-risk patients after hip surgery. N Engl J Med 2011; 365:2453.
- Salpeter SR, Buckley JS, Chatterjee S. Impact of more restrictive blood transfusion strategies on clinical outcomes: a meta-analysis and systematic review. Am J Med 2014; 127:124.
- Rohde JM, Dimcheff DE, Blumberg N, et al. Health care-associated infection after red blood cell transfusion: a systematic review and meta-analysis. JAMA 2014; 311:1317.
- Bennett J, Haynes S, Torella F, et al. Acute normovolemic hemodilution in moderate blood loss surgery: a randomized controlled trial. Transfusion 2006; 46:1097.
- Jarnagin WR, Gonen M, Maithel SK, et al. A prospective randomized trial of acute normovolemic hemodilution compared to standard intraoperative management in patients undergoing major hepatic resection. Ann Surg 2008; 248:360.
- Naqash IA, Draboo MA, Lone AQ, et al. Evaluation of acute normovolemic hemodilution and autotransfusion in neurosurgical patients undergoing excision of intracranial meningioma. J Anaesthesiol Clin Pharmacol 2011; 27:54.
- Zhou X, Zhang C, Wang Y, et al. Preoperative Acute Normovolemic Hemodilution for Minimizing Allogeneic Blood Transfusion: A Meta-Analysis. Anesth Analg 2015; 121:1443.
- Stehling L, Zauder HL. Acute normovolemic hemodilution. Transfusion 1991; 31:857.
- Fan FC, Chen RY, Schuessler GB, Chien S. Effects of hematocrit variations on regional hemodynamics and oxygen transport in the dog. Am J Physiol 1980; 238:H545.
- Rosberg B. Blood coagulation during and after normovolemic hemodilution in elective surgery. Ann Clin Res 1981; 13 Suppl 33:84.
- Milam JD, Austin SF, Nihill MR, et al. Use of sufficient hemodilution to prevent coagulopathies following surgical correction of cyanotic heart disease. J Thorac Cardiovasc Surg 1985; 89:623.
- Sahoo TK, Chauhan S, Sahu M, et al. Effects of hemodilution on outcome after modified Blalock-Taussig shunt operation in children with cyanotic congenital heart disease. J Cardiothorac Vasc Anesth 2007; 21:179.
- Segal JB, Blasco-Colmenares E, Norris EJ, Guallar E. Preoperative acute normovolemic hemodilution: a meta-analysis. Transfusion 2004; 44:632.
- Shander A, Perelman S. The long and winding road of acute normovolemic hemodilution. Transfusion 2006; 46:1075.