Surgery – Devices transferring fluids from within one area of body to...
Patent
1995-01-09
1996-10-08
McDermott, Corrine M.
Surgery
Devices transferring fluids from within one area of body to...
604113, 604 96, A61M 500
Patent
active
055626068
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a cannula for draining venous blood directly from both venae cavae, comprising an insertion piece for insertion into the renee cavae through the right atrium, and a connecting piece for coupling with a suction device, wherein the insertion piece has two openings for draining the superior vena cava and the inferior yens cava respectively.
BACKGROUND OF THE INVENTION
Such a cannula is known from the U.S. patent specification 4,309,994. This patent suggests that an opening in the right atrium is made, through which a cannula with Y-shaped branches can be inserted. One branch goes into the inferior vena cava, while the other goes into the superior vena cava. In this way, blood from both venae cavae can be extract d using one cannula.
Using such a cannula, it is possible to block off or to allow access to either one of the venae cavae, along the cannula to the right atrium, so that, if desired, the right atrium can be shut off from the circulatory system of the body; this is known as total bypass and partial bypass.
Opening the right atrium results in the formation of scar tissue, which can cause heart rhythm disturbances that negatively influence the circulation.
SUMMARY OF THE INVENTION
The subject invention aims to avoid damage to the heart and to make a physiological total bypass technique possible.
This subject is realized with the cannula described above in that the insertion piece is substantially greater in length than the distance between both entrances of the venae cavae in the right atrium, and has a diameter allowing insertion into the right atrium through the entrances of the venae cavae and across into the opposite vena cava, wherein the insertion piece comprises an opening near the free end, and a side opening, near the junction with the connection piece, and in that the cannula is provided sealing means which seal the cannula after insertion through the incision made in the vena cava.
The invention is based on the idea that an incision should no longer be made in the right atrium, but instead, in one of the venae cavae, and that the entrance of the vena cava in the right atrium should be used for introducing the insertion piece of the cannula. To achieve this, either one of the venae cavae must be opened. In both cases, it is also possible to use the cannula for draining blood from the vena cava which received the incision. To this end, it is preferable to make a bend in the cannula, and to make an opening in an extension of the insertion piece. The angle of the bend should, especially, lie in between 90.degree. and 145.degree.. The cannula can drain the blood out of the vena cava which was incised through the side opening, and can drain the blood from the opposite vena cava through the open end of the insertion piece. Both bloodstreams should be drained, via the cannula, into the connecting piece, possibly being lead via an internal profile, designed to promote optimal flow; additionally, the internal diameter of the connecting piece should, in comparison with the internal diameter of the insertion piece, be proportional to the transported bloodstreams.
The proximity of the side opening in the cannula to the insertion point in the vena cars makes means for sealing off the cannula at the insertion point necessary. A flexible flange on the connecting piece, which contacts with the outside of the insertion point, provides such a seal, and can also serve to secure placement of the cannula.
A supplementary seal for the cannula at the insertion point could be a ring-shaped, inflatable seal, or cuff, around the side opening, which can seal off the direct access from the incised yena cava to the right atrium, and also centers the cannula in the yena cava. By using such a seal, partial bypass can be done, because the blood from the side opening and from the insertion part of the cannula can reach the opposite vena cava and from there, the right atrium. For this purpose, an independently inflatable cuff, with a duct containing a valve, can be made.
W
REFERENCES:
patent: 3995617 (1976-12-01), Watkins et al.
patent: 4309994 (1982-01-01), Grunwald
Leeds, S., "A Cannula for Simultaneous Drainage of Both Cavae in Artificial Heart Experiments", Proceedings of the Society for Experimental Biology and Medicine, Oct.-Dec. 1950 (inclusive), vol. 75, pp. 468-469.
Gring N. Kent
McDermott Corrine M.
LandOfFree
Bi-caval cannula does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bi-caval cannula, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bi-caval cannula will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-53732