title: Bloodless spinal surgery: a review of the normovolemic hemodilution technique.
abstract: BACKGROUND
  "Bloodless spinal surgery" predominantly refers to NH, a procedure that minimizes blood transfusion requirements. By limiting or eliminating allogeneic transfusions, NH reduces the risk of transmitting HIV or hepatitis, and the need for predonating autologous blood with the risks of blood bank contamination, misidentification, or the removal of coagulation factors (fresh frozen plasma, platelets).
  
  
  METHODS
  The NH technique technically requires the controlled removal of a volume of whole blood at the beginning of surgery. The quantity removed is dependent upon the preoperative hematocrit and varies from 1 to 3 U. Each 1 mL of whole blood removed is then replaced with 3 to 4 mL of colloid or crystalloid. Intraoperatively, NH typically reduces the hematocrit to 28%, taking care to avoid hemodynamic compromise through adequate volume replacement.
  
  
  RESULTS
  For adolescents undergoing scoliosis/spinal fusions, NH reduced allogeneic transfusion requirements from 79% to 37% [Cha CW, Deible C, Muzzonigro T, et al. Allogeneic transfusion requirements after autologous donations in posterior lumbar surgeries. Spine. 2002; 27(1) 99-104]. Without NH, 40% of patients undergoing instrumented lumbar spine fusions in one series required allogeneic blood transfusions [Catoire P, Saada M, Liu N, et al. Effect of preoperative normovolemic hemodilution on left ventricular segmental wall motion during abdominal aortic surgery. Anesth Analg (US). 1992; 75(5): 654-9.]. With the use of NH in a comparable series, this frequency was reduced to 23.5% [Epstein NE, Peller A, Korsh J, et al. Impact of intraoperative normovolemic hemodilution on transfusion requirements for 68 patients undergoing lumbar laminectomies with instrumented posterolateral fusion. Spine. 2006; 31(19): 2227-2230].
  
  
  CONCLUSIONS
  This study reviews how NH may be safely and effectively used by spinal surgeons, particularly for those who perform multilevel lumbar laminectomies with or without fusion.
authors.affiliation: Long Island Neurosurgical Associates, New Hyde Park, NY 11042, USA. dch3@columbia.edu
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Epstein
mesh_terms: D000293:Adolescent; D000328:Adult; D001803:Blood Transfusion; D001810:Blood Volume; D002648:Child; D006438:Hemodilution / Q000379:methods*; D006801:Humans; D007796:Laminectomy; D013123:Spinal Fusion