ObjectiveThe effects of microfibrillar collagen hemostat (Colgel) and oxidized cellulose (Surgicel) on bleeding and allogeneic transfusions were compared in cardiac operations with a predicted high risk of bleeding. MethodsBetween August 1999 and November 2001, 71 patients undergoing elective, high risk of bleeding operations were studied after giving informed consent. The procedures included repeat cardiac operations (aorta-coronary bypass operations or valvular operations), ascending aortic aneurysm repair necessitating deep hypothermic circulatory arrest, and ascending aortic grafting without deep hypothermic circulatory arrest. Subjects were excluded if they had recent (<5 days) acetylsalicylic acid ingestion, thrombolytic therapy, or anticoagulant therapy (heparin <4 hours preoperatively or warfarin <3 days preoperatively). Consenting subjects were randomized to receive either Colgel or Surgicel. ResultsChest tube drainage in the first 24 hours was 373 ± 143 mL in the Colgel group and 571 ± 144 mL in the Surgicel group (P = .01). Total postoperative chest tube drainage was 423 ± 154 mL (range, 280-1100 mL) in the Colgel group and 677 ± 128 mL (range, 285-1350 mL) in the Surgicel group (P = .01). In addition, chest tube drainage was compared between the 2 groups every 3 hours after operation. Blood loss in the first 3 postoperative hours was significantly less in the Colgel group (132 ± 41 vs 228 ± 57 mL, P < .001). In the following 3-hour interval, this significant difference persisted (67 ± 24 vs 121 ± 49 mL, P < .001). ConclusionsIn conclusion, the easy application, low cost, and significant blood-loss reduction effect of microfibrillar collagen powder renders this agent attractive for cardiac operations associated with high risk of bleeding.