Modified Open Circuit and Vacuum-assisted Venous Return Reduces Blood Usage During Cardiopulmonary Bypass

Objectives: To determine whether vacuum-assisted venous return has clinical advantages over conventional gravity drainage apart from allowing the use of smaller cannulas, shorter tubing and reduced priming. Methods: A total of 80 CABG operations were performed at our institution between July 1999 to December 2010, using vacuum-assisted venous return with small venous cannulas connected to short tubing. These were randomized with 80 CABG operations using conventional gravity drainage. Priming volume, hematocrit value, red blood cell usage, and total blood product usage were compared by means of multivariate analysis. Results: The priming volume was 780+/-140mL for small-cannula vacuumassisted venous return, 1300+/-88mL for gravity drainage (P <.0001). Smaller priming resulted in higher hematocrit values both at the beginning of cardiopulmonary bypass (26%+/-5% compared with 21%+/-4%, respectively, P <.0001) and at the end (28%+/-4% compared with 24%+/-4%, respectively, P <.0001). Red cell transfusions were used in 12% of the patients having small-cannula vacuum-assisted venous return and 41% of the patients having gravity drainage (P =.001); total blood product usage was 15% and 61%, respectively (P =.001). Despite a postoperative blood loss, length of stay in intensive care unit was similar in both groups; the association of vacuum-assisted venous return with lowered blood product usage was confirmed also in the postoperative period. Conclusions: Modified open circuit and vacuum-assisted venous return result in 1) higher hematocrit values during cardiopulmonary bypass and 2) decreased red cell and total blood product usage