Biochemical evaluation of vacuum-assisted venous drainage: a randomized, prospective study.

Aims of the Study: In this prospective, randomized study, we investigate the potential advantages of vacuum-assisted venous drainage (VAVD), compared to gravitational drainage (GD), in patients undergoing first-time coronary artery bypass graft (CABG) surgery, concerning biochemical markers of organ and blood cell damage.
Materials and Methods: Seventy-two consecutive patients were randomized into two groups ['Vacuum' (VAVD) n=36; 'Not vacuum' (GD) n=36]. VAVD was achieved using a wall vacuum source and with a suction regulator connected to the vent port of the hardshell venous reservoir. In the VAVD group, we used 28-French venous cannulas, and 36-French in the GD group. In the VAVD group, we measured arterial perfusion flow (APF) and the venous reservoir volume (VRV) with and without vacuum application just after starting extracorporeal circulation (ECC). Six blood samples were drawn at different times before, during and after ECC. Routine blood tests were performed to evaluate hemolysis, and hepatic and renal function.
Results: The two groups were similar in terms of preoperative and operative characteristics. There were no significant differences in biochemical markers of organ function or hemolysis between the two groups. In the VAVD patients, platelet count was higher at 24 h after the end of the operation (VAVD 151.77+/-50.28 microl versus Not vacuum 124.93+/-41.60 microl, p=0.028). With the narrower venous cannulas (28-French), only VAVD achieved a satisfactory APF (VAVD 2.35+/-0.38 l/min/m2 versus GD 1.88+/-0.27 l/min/m2, p=0.002), with a larger VRV (VAVD 1091.67+/-421 ml versus GD 808.33+/-284.31 ml, p=0.025).
Conclusion: Vacuum-assisted venous drainage is a technique comparable to gravitational drainage with regard to hemolysis and organ perfusion. It allows better perfusion flow and heart decompression with smaller venous cannulas. This study suggests reduced platelet consumption with VAVD.