Safety and efficacy of shed mediastinal blood transfusion after cardiac surgery: A multicenter observational study

Objective: To examine the efficacy and safety of shed mediastinal blood (SM B) transfusion in preventing allogenic red blood cell(RBC) transfusion. Design: An observational clinical study. Setting: Twelve US academic medical centers. Participants: Six hundred seventeen patients undergoing elective primary co ronary artery bypass grafting. Interventions: Patients were administered SMB transfusion or not, according to institutional and individual practice, without random assignment. Measurements and Results: The independent effect of SMB transfusion on post operative RBC transfusion was examined by multivariable modeling. Potential complications of SMB transfusion, such as bleeding and infection, were exa mined. Three hundred twelve of the study patients (51%) received postoperat ive SMB transfusion (mean volume, 554 +/- 359 mt). Patients transfused with SMB had significantly lower volumes of RBC transfusion than those not rece iving SMB (0.86 +/- 1.50 v 1.08 +/- 1.65 units; p < 0.05). However, multiva riable analysis showed that SMB transfusion was not predictive of postopera tive RBC transfusion. Demographic factors (older age, female sex), institut ion, and postoperative events (greater chest tube drainage, lower hemoglobi n level on arrival to the intensive care unit, and use of inotropes) were s ignificant predictors of RBC transfusion. The volume of chest tube drainage on the operative day (707 +/- 392 v 673 +/- 460 mt; p = 0.30), reoperation for hemorrhage (3.1% v 2.5%; p = 0.68), and overall frequency of infection (5.8% v 6.6%; p = 0.81) were similar between patients receiving and not re ceiving SMB, respectively. However, in patients who did not receive allogen ic RBC transfusion, there was a significantly greater frequency of wound in fection in the SMB group (3.6% v 0%; p = 0.02). Conclusion: These data suggest that SMB is ineffective as a blood conservat ion method and may be associated with a greater frequency of wound infectio n. Copyright (C) 1999 by W.B. Saunders Company.