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Abstract

The venous reservoir accommodates variations in the total volume of blood circulating in the extracorporeal circuit during cardiopulmonary bypass (CPB). It is connected between the patient and the arterial pump and serves as a compliance chamber. Venous drainage by gravity alone provides an inadequate rate of blood return during procedures such as minimally invasive cardiac surgery and bypass via femoral cannulation. In these cases the resistance of the venous cannula limits the maximum achievable flow. Vacuum augmented venous drainage (VAVD) is a technique that overcomes flow limitations by applying suction to the hard shell reservoir thereby increasing the pressure difference between the venous site and venous reservoir. VAVD allows for a decrease in the inner diameter of the venous line, thereby reducing prime volume, as well as the use of a smaller cannula that translates to an easier insertion, a better surgical view, and a smaller surgical incision. VAVD precludes the use of the safer, soft-shell closed venous reservoir (bag) unless a more expensive and complicated two-pump system is used. The present invention describes a soft-shell venous reservoir that allows VAVD using a single pump. The invention describes a soft shell reservoir that is sealed within a, preferably, clear rigid housing. A gas port connected to the space between the bag and rigid housing is used to adjust the pressure within that space: it allows the user to adjust the 'atmospheric' pressure about the external walls of the soft-shell reservoir. Another aspect of the invention improves gas bubble removal.

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First Claim