title: Mild hypothermia increases blood loss and transfusion requirements during total hip arthroplasty.
abstract: BACKGROUND
  In-vitro studies indicate that platelet function and the coagulation cascade are impaired by hypothermia. However, the extent to which perioperative hypothermia influences bleeding during surgery remains unknown. Accordingly, we tested the hypothesis that mild hypothermia increases blood loss and allogeneic transfusion requirements during hip arthroplasty.
  
  
  METHODS
  Blood loss and transfusion requirements were evaluated in 60 patients undergoing primary, unilateral total hip arthroplasties who were randomly assigned to normothermia (final intraoperative core temperature 36.6 [0.4] degrees C) or mild hypothermia (35.0 [0.5] degrees C). Crystalloid, colloid, scavenged red cells, and allogeneic blood were administered by strict protocol.
  
  
  RESULTS
  Intra- and postoperative blood loss was significantly greater in the hypothermic patients: 2.2 (0.5) L vs 1.7 (0.3) L, p < 0.001). Eight units of allogeneic packed red cells were required in seven of the 30 hypothermic patients, whereas only one normothermic patient required a unit of allogeneic blood (p < 0.05 for administered volume). A typical decrease in core temperature in patients undergoing hip arthroplasty will thus augment blood loss by approximately 500 mL.
  
  
  CONCLUSIONS
  The maintenance of intraoperative normothermia reduces blood loss and allogeneic blood requirements in patients undergoing total hip arthroplasty.
authors.affiliation: Department of Anaesthesia and Intensive Care Medicine, Hospital of Amstetten, Austria.
authors.forename: H
authors.initials: H
authors.lastname: Schmied
authors.forename: A
authors.initials: A
authors.lastname: Kurz
authors.forename: D I
authors.initials: DI
authors.lastname: Sessler
authors.forename: S
authors.initials: S
authors.lastname: Kozek
authors.forename: A
authors.initials: A
authors.lastname: Reiter
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016063:Blood Loss, Surgical / Q000706:statistics & numerical data*; D001803:Blood Transfusion / Q000706:statistics & numerical data*; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged