Gas separation: apparatus – Degasifying means for liquid – Defoaming means
Reexamination Certificate
1999-12-22
2001-03-27
Weiss, John G. (Department: 3761)
Gas separation: apparatus
Degasifying means for liquid
Defoaming means
C096S195000, C096S209000, C604S005010, C604S406000, C210S188000
Reexamination Certificate
active
06206954
ABSTRACT:
BACKGROUND OF THE INVENTION
Blood sets are used for conveying blood between a patient and an extracorporeal blood treatment device such as a dialyzer. Typically, an extracorporeal blood treatment system uses two separate blood sets: an arterial blood set and a venous blood set for respectively conveying blood from the patient to the treatment device, and for conveying blood from the treatment device back to the patient. Accordingly, an extracorporeal blood treatment system such as a hemodialysis system generally has a complex series of tubes and other set components such as bubble trap chambers, peristaltic pump tubing, branch connectors, and the like. The handling and set up of such blood sets with a device such as a hemodialyzer is complex and confusing.
By this invention, the handling of extracorporeal blood treatment sets can be simplified, with greater flexibility of use because the same sets can be used with different designs of commercially available dialysis machines. Particularly, by this invention it becomes practical to provide a flexible tubing blood set that is both an arterial set and a venous set, for the simplification of installation and priming, and also for a possible reduction in the number of connections that must be made, and reduction in cost and overall complexity. Also, new designs of blood chambers are used herein.
DESCRIPTION OF THE INVENTION
By this invention, a combined arterial-venous blood flow set may be provided for extracorporeal blood treatment, which sets may fit a plurality of existing dialysis machines. The set comprises connected lengths of flexible tubing for receiving blood from the patient, for conveying the blood to a blood processing device such as a dialyzer, and for returning the blood to the patient.
The blood flow set of this invention comprises an optional first bubble trap chamber which is connected in series flow between two of the lengths of tubing at an arterial flow position, namely a flow position which is downstream from the patient but upstream from the blood processing device.
A second bubble trap chamber may be connected in series flow between two of the lengths of tubing at a venous flow position, which is downstream from the blood processing device and upstream from the patient, so that blood may be circulated through the extracorporeal system from the patient and then returned to the patient.
A first portion of the tubing, which is in a flow position upstream from the blood processing device, extends by the second bubble trap chamber. This first portion of tubing is physically connected to the bubble trap chamber without flow connection with the bubble trap chamber. This helps to stabilize the positioning of components of the flow set.
Particularly, one of the lengths of tubing may comprise peristaltic pump tubing. Preferably, the first bubble trap chamber is directly connected in flow communication to an end of the pump tubing. The second bubble trap chamber may be externally connected to tubing adjacent the pump tubing (including the possibility of being directly externally connected to the pump tubing), but this second chamber is out of direct flow communication therewith. Instead, the pump tubing adjacent to the second bubble trap chamber, and connected tubing, may comprise the first portion of the tubing as described above which is physically connected to the second bubble trap chamber without direct flow connection. Blood from the pump tubing passes externally by the second bubble trap chamber to the dialyzer or other blood treatment device. Then, the blood is returned to the second bubble trap chamber for final debubbling before being returned to the patient.
This arrangement provides a significant improvement in the ease of installation of the arterial and venous set into, particularly, conventional commercial hemodialysis machines or other blood treatment devices, such as low density lipid (LDL) removing systems. As the peristaltic pump tubing is installed into the peristaltic pump housing, the two bubble trap chambers which are preferably present are positioned in known positions adjacent to the pump housing, causing a known positioning of the various chambers and tubing sections, for connection to the dialyzer and to the patient with greater ease than is found with the separate installation and connection of separate arterial sets and venous sets. Specifically, the bottom of the pump housing of the dialysis machine can help to position the set chambers as the set is installed, avoiding the need for extra tube retention clips.
The second bubble trap chamber is also novel in itself, comprising a chamber-defining housing, plus a flow inlet tube connected to a length of the flexible tubing which is in a flow position downstream from the blood processing device (typically a dialyzer). The flow inlet tube extends into the chamber adjacent to one side of the chamber, and has an aperture that directs substantially the entire flow of blood through the inlet tube horizontally into the chamber. The housing also has an outlet port which is positioned adjacent to the chamber bottom, and is further positioned adjacent to an opposed side of the chamber to the one side.
The chamber has a sidewall that defines a flow-diverting indentation positioned between the one side and the opposed side of the chamber. The effect of this flow diverting indentation is to interfere with a direct flow path of blood flowing through the chamber between the flow inlet tube and the outlet port. Thus, a substantial portion of the blood entering the chamber, typically most of the blood, follows a circuitous path around the peripheral wall of the chamber in travelling from the flow inlet tube to the outlet port. This longer flow path gives bubbles in the blood more time to rise to the surface of the chamber, keeping away from the outlet port, which is positioned adjacent to the chamber bottom. Thus, a smaller bubble trap can be used having a longer flow path and equal or better bubble removing effect than larger bubble traps of different designs. This provides the advantage that the blood chamber of this invention may have less volume, which means that less blood is maintained outside of the patient during the blood handling process.
Preferably, the aperture of the flow inlet tube faces away from the outlet port by at least about 90°, to facilitate this longer, circuitous blood flow path through the bubble trap chamber.
Typically, the first portion of tubing, referred to above, is externally connected to the second bubble trap chamber at a position to permit the fluid flow of the first portion of tubing to pass through a recess defined by the outside surface of the portion of the second bubble trap chamber sidewall that defines the indentation. Thus, the recess-defining side of the bubble trap chamber can be rather flat, and can stably rest against a flat surface of dialyzer hardware during use, while providing the external blood flow passageway adjacent to the side and in the recess as described above. The chamber top can also be substantially flat, to allow it to stably rest against the underside of a commercial dialysis machine pump housing. This facilitates the use of the chamber and set of this invention with a variety of conventionally available dialysis machine hardware, for which the combined arterial-venous set of this invention comprises a removable, and often disposable, component along with the membrane dialyzer unit or other blood processing device such as an LDL filter.
Specifically, the housing of the second bubble trap chamber carries an integral tube extending through the above described recess, with the integral tube having opposed ends which may be connected to separate lengths of the flexible tubing of the set, to define the first portion of the tubing.
The housing of the second bubble trap chamber may define a cup-like main body which, in turn, defines a bottom wall and sidewall. Also, the housing comprises a fitting lid which is sealed to an open mouth of the main body. The fitting lid thus defines a closed chamber with t
Schnell William J.
Utterberg David S.
Cho David J.
DSU Medical Corporation
Ellis Garrettson
Seyfarth Shaw
Weiss John G.
LandOfFree
Blood set and chamber does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Blood set and chamber, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Blood set and chamber will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2531121