title: Intra-operative intravenous fluid restriction reduces perioperative red blood cell transfusion in elective cardiac surgery, especially in transfusion-prone patients: a prospective, randomized controlled trial.
abstract: BACKGROUND
  Cardiac surgery is a major consumer of blood products, and hemodilution increases transfusion requirements during cardiac surgery under CPB. As intraoperative parenteral fluids contribute to hemodilution, we evaluated the hypothesis that intraoperative fluid restriction reduces packed red-cell (PRC) use, especially in transfusion-prone adults undergoing elective cardiac surgery.
  
  
  METHODS
  192 patients were randomly assigned to restrictive (group A, 100 pts), or liberal (group B, 92 pts) intraoperative intravenous fluid administration. All operations were conducted by the same team (same surgeon and perfusionist). After anesthesia induction, intravenous fluids were turned off in Group A (fluid restriction) patients, who only received fluids if directed by protocol. In contrast, intravenous fluid administration was unrestricted in group B. Transfusion decisions were made by the attending anesthesiologist, based on identical transfusion guidelines for both groups.
  
  
  RESULTS
  137 of 192 patients received 289 PRC units in total. Age, sex, weight, height, BMI, BSA, LVEF, CPB duration and surgery duration did not differ between groups. Fluid balance was less positive in Group A. Fewer group A patients (62/100) required transfusion compared to group B (75/92, p < 0.04). Group A patients received fewer PRC units (113) compared to group B (176; p < 0.0001). Intraoperatively, the number of transfused units and transfused patients was lower in group A (31 u in 19 pts vs. 111 u in 62 pts; p < 0.001). Transfusions in ICU did not differ significantly between groups. Transfused patients had higher age, lower weight, height, BSA and preoperative hematocrit, but no difference in BMI or discharge hematocrit. Group B (p < 0.005) and female gender (p < 0.001) were associated with higher transfusion probability. Logistic regression identified group and preoperative hematocrit as significant predictors of transfusion.
  
  
  CONCLUSIONS
  Our data suggest that fluid restriction reduces intraoperative PRC transfusions without significantly increasing postoperative transfusions in cardiac surgery; this effect is more pronounced in transfusion-prone patients.
  
  
  BACKGROUND
  NCT00600704, at the United States National Institutes of Health.
authors.affiliation: Cardiac Anesthesia Unit, Department of Anesthesiology, University Hospital of Larissa, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Vretzakis
authors.forename: Athina
authors.initials: A
authors.lastname: Kleitsaki
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Stamoulis
authors.forename: Metaxia
authors.initials: M
authors.lastname: Bareka
authors.forename: Stavroula
authors.initials: S
authors.lastname: Georgopoulou
authors.forename: Menelaos
authors.initials: M
authors.lastname: Karanikolas
authors.forename: Athanasios
authors.initials: A
authors.lastname: Giannoukas
mesh_terms: D000368:Aged; D016063:Blood Loss, Surgical; D006348:Cardiac Surgical Procedures; D016009:Chi-Square Distribution; D017707:Erythrocyte Transfusion; D005260:Female; D006438:Hemodilution / Q000009:adverse effects*; D006801:Humans; D007262:Infusions, Intravenous / Q000009:adverse effects*; D007430:Intraoperative Care; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D018709:Statistics, Nonparametric; D016896:Treatment Outcome