title: The effect of retrograde autologous priming on intraoperative blood product transfusion in coronary artery bypass grafting.
abstract: BACKGROUND
  Retrograde autologous priming (RAP) of the cardiopulmonary bypass (CPB) circuit could reduce the degree of haemodilution associated with priming with acellular solutions. However, there is no strong evidence to prove that the practice of RAP reduced intraoperative packed red cell (PRC) or blood product transfusion.
  
  
  OBJECTIVE
  To evaluate the effect of RAP on intraoperative PRC usage in coronary artery bypass grafting (CABG).
  
  
  METHODS
  This study is a prospective, observational study on patients who underwent first-time, isolated CABG using CPB between April 2012 and July 2012. Two groups of patients were identified: 1. Non-RAP group (n=128) and 2. RAP group (n=73). The primary outcome for the study was the amount of PRC and blood product usage between the induction of anaesthesia and the cessation of CPB.
  
  
  RESULTS
  Use of PRC and blood products in the operating room was comparable in both groups. Univariate logistic regression showed that RAP was not an independent predictor of PRC or blood product transfusion (p=0.43). Multivariate logistic regression showed that CPB time, preoperative haemoglobin (Hb) levels and creatinine clearance were independent predictors of blood product transfusion.
  
  
  CONCLUSIONS
  Practising RAP with mean volumes of 300 ml does not necessarily reduce PRC and other blood product transfusion requirements during CABG. In our practice, RAP was performed, aiming at displacing CPB circuit prime volume with which the perfusionist felt comfortable and dictated by haemodynamic parameters prior to commencing CPB. We presume this is the case in many units around the world. This practice, in our opinion, is not enough to achieve the benefits of RAP, if any, in the form of a reduction of packed red cell transfusion requirements. The true advantages of RAP in cardiac surgery need to be studied in a prospective, randomized, controlled trial.
authors.affiliation: 1Papworth Hospital NHS Trust, Cambridge, UK.
authors.forename: A
authors.initials: A
authors.lastname: Nanjappa
authors.forename: J
authors.initials: J
authors.lastname: Gill
authors.forename: U
authors.initials: U
authors.lastname: Sadat
authors.forename: S
authors.initials: S
authors.lastname: Colah
authors.forename: Y
authors.initials: Y
authors.lastname: Abu-Omar
authors.forename: S
authors.initials: S
authors.lastname: Nair
mesh_terms: D000368:Aged; D001804:Blood Transfusion, Autologous / Q000379:methods*; D001026:Coronary Artery Bypass / Q000379:methods*; D017707:Erythrocyte Transfusion / Q000379:methods*; D005260:Female; D006438:Hemodilution / Q000379:methods; D006801:Humans; D007430:Intraoperative Care / Q000379:methods; D008297:Male; D011446:Prospective Studies; D016896:Treatment Outcome
keywords: RAP; blood transfusion; cardiac surgery; perfusion; priming