title: Blood use in patients undergoing coronary artery bypass surgery: impact of cardiopulmonary bypass pump, hematocrit, gender, age, and body weight.
abstract: We investigated the impact of cardiopulmonary bypass pump (CPB), hematocrit, gender, age, and body weight on blood use in patients undergoing coronary artery bypass graft surgery at a major university hospital. Participants were 1235 consecutive patients undergoing primary coronary artery surgery over a period of 2 yr (1999 and 2000); 681 patients underwent coronary surgery with use of CPB, and 554 patients underwent off-pump coronary artery bypass surgery using a median sternotomy incision. There were 881 males and 354 females. Average packed red blood cells (PRBC) transfusion for patients on CPB was 3.4 U compared with 1.6 U for the off-pump group (P = <0.001). Patients on CPB received more frequent PRBC transfusion (72.5%) compared with 45.7% of off-pump patients (P = <0.001). Average PRBC transfusion for males was 2.2 U compared with 3.6 U for females (P = <0.001). A lower percentage of males (52.6%) than females (79.4%) received transfusion (P = <0.001). The impact of CPB, off-pump status, preoperative hematocrit <35%, gender, age >or=65 yr, and weight <or=83 kilograms using median values as cut points, on blood use was examined using logistic regression models. Use of CPB, preoperative hematocrit, (<35%) female gender, increasing age, and decreased body weight were significant predictors of transfusion (P = <0.001). Preoperative hematocrit <35% and use of CPB were the strongest predictors of PRBC transfusion.
  
  
  CONCLUSIONS
  We examined the impact of cardiopulmonary bypass, preoperative hematocrit, gender, age, and body weight on blood use in patients undergoing primary coronary artery bypass surgery at a tertiary care institution. We found that all five of these variables are significant predictors of blood use in patients undergoing coronary artery bypass surgery.
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology; D001803:Blood Transfusion / Q000706:statistics & numerical data*; D001835:Body Weight / Q000502:physiology; D002315:Cardiopulmonary Bypass / Q000295:instrumentation*; D001026:Coronary Artery Bypass; D016208:Databases, Factual; D017707:Erythrocyte Transfusion; D005112:Extracorporeal Circulation / Q000009:adverse effects* / Q000295:instrumentation; D005260:Female; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012727:Sex Characteristics