An improved blood reservoir formed by opposed, flexible sheets has a screen sandwiched between the sheets defining an input chamber, an output chamber, and vent chamber. A vent is in fluid communication with the vent chamber. An outlet is in fluid communication with the output chamber. One or more inlets direct blood into the input chamber through apertures that direct blood upward and along the screen, allowing gas bubbles entrained in the blood to escape through the vent. Support springs around the inlets allow them to be flexed without kinking. The reservoir can be coupled to an improved mounting board for use.
Venous reservoirs are interposed between the patient and the arterial pump and serve to remove air bubbles and provide compliance that accommodates variations in the volume of blood circulating in the extracorporeal circuit during cardiopulmonary bypass (CPB). The invention is a reservoir that incorporates automated means to remove air bubbles from the venous line prior to the blood entering the arterial blood pump. In form, the reservoir includes means that handle foam prior to the blood entering the blood pump. In another form, the invention provides means that improve air removal in a soft shell venous reservoir. These features are applicable to CPB circuits using gravity drainage or vacuum assisted venous drainage.
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.
A design and method of operation are disclosed for a fluid control conduit of a blood reservoir. The venous blood inflow conduit includes a fluid control nozzle and a base. When assembled together the nozzle and base form a trap feature which prevents reflux of air or other gas upwardly into the nozzle of the conduit. As a result, during use of the reservoir the conduit normally runs full of venous blood and turbulence of the blood is prevented. In addition, the conduit also functions to divert the downward flowing venous blood in the nozzle into the base at an optimum fluid velocity to overcome the buoyancy effect of air or gas bubbles within the blood.
A bag or reservoir for recirculation washing of blood cells has a top outlet port and bottom inlet port. A method of recirculation washing of blood cells uses the bag in conjunction with a spinning membrane filter. The method can be used in an instrument for magnetic cell selection or a stand-alone cell washing apparatus.
