title: Platelet-rich-plasmapheresis for minimising peri-operative allogeneic blood transfusion.
abstract: BACKGROUND
  Concerns regarding the safety of transfused blood have generated considerable enthusiasm for the use of technologies intended to reduce the use of allogeneic blood (blood from an unrelated donor). Platelet-rich plasmapheresis (PRP) offers an alternative approach to blood conservation.
  
  
  OBJECTIVE
  To examine the evidence for the efficacy of PRP in reducing peri-operative allogeneic red blood cell (RBC) transfusion, and the evidence for any effect on clinical outcomes such as mortality and re-operation rates.
  
  
  METHODS
  We identified studies by searching MEDLINE (1950 to 2009), EMBASE (1980 to 2009), The Cochrane Library (Issue 1, 2009), the Internet (to March 2009) and the reference lists of published articles, reports, and reviews.
  
  
  METHODS
  Controlled parallel group trials in which adult patients, scheduled for non-urgent surgery, were randomised to PRP, or to a control group which did not receive the intervention.
  
  
  METHODS
  Primary outcomes measured were: the number of patients exposed to allogeneic RBC transfusion, and the amount of RBC transfused. Other outcomes measured were: the number of patients exposed to allogeneic platelet transfusions, fresh frozen plasma, and cryoprecipitate, blood loss, re-operation for bleeding, post-operative complications (thrombosis), mortality, and length of hospital stay. Treatment effects were pooled using a random-effects model. Trial quality was assessed using criteria proposed by Schulz et al (Schulz 1995).
  
  
  RESULTS
  Twenty-two trials of PRP were identified that reported data for the number of patients exposed to allogeneic RBC transfusion. These trials evaluated a total of 1589 patients. The relative risk (RR) of exposure to allogeneic blood transfusion in those patients randomised to PRP was 0.73 (95%CI 0.59 to 0.90), equating to a relative risk reduction (RRR) of 27% and a risk difference (RD) of 19% (95%CI 10% to 29%). However, significant heterogeneity of treatment effect was observed (p < 0.00001; I² = 79%). When the four trials by Boldt are excluded, the RR is 0.76 (95% CI 0.62 to 0.93). On average, PRP did not significantly reduce the total volume of RBC transfused (weighted mean difference [WMD] -0.69, 95%CI -1.93 to 0.56 units). Trials provided inadequate data regarding the impact of PRP on morbidity, mortality, and hospital length of stay. Trials were generally small and of poor methodological quality.
  
  
  CONCLUSIONS
  Although the results suggest that PRP is effective in reducing allogeneic RBC transfusion in adult patients undergoing elective surgery, there was considerable heterogeneity of treatment effects and the trials were of poor methodological quality. The available studies provided inadequate data for firm conclusions to be drawn regarding the impact of PRP on clinically important endpoints.
authors.affiliation: Discipline of Clinical Pharmacology, Faculty of Health, University of Newcastle, Level 5, Clinical Sciences Building, Newcastle Mater Hospital, Edith Street, Waratah, Newcastle, New South Wales, Australia, 2298.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Carless
authors.forename: Fraser D
authors.initials: FD
authors.lastname: Rubens
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Anthony
authors.forename: Dianne
authors.initials: D
authors.lastname: O'Connell
authors.forename: David A
authors.initials: DA
authors.lastname: Henry
mesh_terms: D000328:Adult; D016063:Blood Loss, Surgical / Q000517:prevention & control; D017558:Elective Surgical Procedures; D006801:Humans; D010956:Plasmapheresis / Q000379:methods*; D017713:Platelet Transfusion / Q000706:statistics & numerical data*; D016032:Randomized Controlled Trials as Topic; D014184:Transplantation, Homologous