Does vacuum-assisted venous drainage increase gaseous microemboli during cardiopulmonary bypass?
BACKGROUND
Vacuum-assisted venous drainage enables adequate drainage through small-diameter cannulas but concerns are that it results in more gaseous microemboli delivered to the patient.


METHODS
Five identical embolus detectors monitored the propagation of entrained air through a cardiopulmonary bypass (CPB) model. The ability of the CPB circuit to remove gaseous microemboli was studied with vacuum-assisted venous drainage and gravity siphon venous drainage using different pump speeds and rates of gaseous microemboli delivery.


RESULTS
Under all conditions entrained venous air resulted in the detection of gaseous microemboli in the perfusate after the arterial filter. In blood-primed circuits, increased flow rates and higher levels of vacuum-assisted venous drainage were independently associated with increased gaseous microemboli counts in the arterial line. Vacuum-assisted venous drainage at -40 mm Hg did not significantly increase gaseous microemboli activity when compared with gravity siphon venous drainage at 4 L/min flow rate.


CONCLUSIONS
Vacuum-assisted venous drainage at -40 mm Hg does not statistically reduce the ability of the CPB circuit to remove gaseous microemboli at lower pump rates. High levels of vacuum and increased pump flow rates should be avoided. Air should not be introduced into the venous line.
Jones
Timothy J
TJ
Department of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1009, USA.
Deal
Dwight D
DD
Vernon
Jason C
JC
Blackburn
Noel
N
Stump
David A
DA
D002315:Cardiopulmonary Bypass / Q000379:methods*; D004618:Embolism, Air / Q000209:etiology*; D013396:Suction / Q000009:adverse effects*; D014618:Vacuum; D014680:Veins