Single stage venous catheter

A single stage venous catheter for use in open heart surgery which has an extended insertion end provided with axially extending open-sided sectorial grooves around a common axis, the grooves terminating in a common receiving chamber surrounded by circumferentially spaced multiple fins or ribs to maintain the proper clearance for the catheter chamber.

FIELD OF INVENTION 
Catheters for introduction to the heart organ during open heart surgery. 
BACKGROUND AND OBJECTS OF THE INVENTION 
In heart surgery, life support machines are utilized to perform temporarily 
the function of the heart and lungs while the patient's heart is being 
surgically serviced such as the repair of heart wall lesions, installation 
of a valve, and by-pass artery work. The life support machine must take 
the flowing blood from the patient, maintain the temperature, pressure, 
and flow rate within certain physiologic limits, and provide the lung 
function. 
In the course of an operation of this type, it is essential that a 
change-over be accomplished from the natural heart function to the 
machine. This involves installation of a venous return catheter into the 
right atrium (chamber) of the heart to serve as a drainage supply 
connection to the pumping machine. Experience has shown that, when used in 
certain procedures such as coronary artery by-pass to the circumflex 
coronary artery, anatomical variations and intra-operative manipulation of 
the heart may cause a reduction in venous drainage due to distortion of 
the atrial walls and vena cava or shifting of the catheter position. 
The traditional method of venous drainage has been to place two catheters, 
one into the superior vena cava. This method provides good venous return 
in all operative circumstances but requires that additional time be spent 
placing the two catheters. Single catheter venous drainage from the right 
atrium was developed to simplify and shorten the time required for 
cannulation. However, the disadvantage of single catheter drainage from 
the right atrium only is its limitation to those procedures not requiring 
the previously discussed operative manipulations which reduce the blood 
flow. A two-stage catheter has also been developed to combine the 
desirable simplicity, convenience, and time savings of the single catheter 
with the higher reliability of the two catheter technique. 
It is an object of the present invention to provide a single stage venous 
catheter which achieves the advantages of the double catheter on the 
two-stage catheter, which is easily installed and which insures adequate 
drainage during a heart operation. It is a further object to provide a 
catheter designed for maximum flow and one which can be installed with a 
minimal loss of blood and through a single aperture created by the 
amputation or incision of a portion of the distal appendage. 
One type of two-stage catheter is disclosed in U.S. Pat. No. 4,129,129, 
issued to Bruce A. Amrine on Dec. 12, 1978. The present invention relates 
to a simplified catheter construction which is readily molded in a 
one-piece unit and which performs the function of a two-point pick up 
while eliminating the more complex internal passages. 
Other objects and features of the invention will be apparent in the 
following detailed description and claims in which there is set forth the 
invention together with details to enable a person to practice the 
invention, all in connection with the best mode presently contemplated for 
the invention.

WITH REFERENCE TO THE DRAWINGS, in FIG. 1, an elevation of the single stage 
venous catheter is shown. The section 10 bracketed as A is composed of 
four fins 12 each 90.degree. apart joined at the axis. FIG. 2 illustrates 
the end view of the cannula showing the fins 12. FIG. 4 illustrates the 
sectional view of these fins 12. The tip of this section of the cannula 
tapers at 14 to a rounded end 16. Thus, this portion of the cannula forms 
longitudinally extending open-sided sectorial passages around a common 
axis. 
The bracketed section B in FIG. 1 shows the fins 12 enlarging in diameter 
and thickness to fins 20 up to a root section 22 of the cannula with a 
slight decrease in diameter past the point 24. This is illustrated in the 
end view of FIG. 2. 
With further reference to section B of the cannula, four additional fins 30 
originate at the root section 22 extending away from the root section 
toward the tip 16. Four of these fins 30 are located half-way between fins 
20 bisecting the 90.degree. angle between fins 20. These fins 30 extend 
toward the tip a little beyond the point 24 and are shown in sectional 
view FIG. 6. 
Eight shorter fins 40 bisect the space between fins 20 and 30, these 
terminating short of the point 24. Sectional view FIG. 7 shows these fins 
40. 
The root section 22 shown in section in FIG. 5 has a fist circular opening 
42 to receive the end of tubing 44 leading to the life support system. An 
opening 52 of smaller diameter provides a shoulder 54 against which the 
end of the tubing can abut. The opening 52 provides a clear passage from 
the tubing to the sectorial passages 60 between fins 20-12 as shown in 
FIGS. 2 and 3. 
It will be noted that, while fins 12-20 extend to a common axis of the 
cannula, the shorter fins 30 and 40 have an inner diameter terminating at 
the inner diameter of the opening 52. 
In the use of the above-described single stage venous catheter, an opening 
into the heart is surgically instituted as is the practice in open heart 
surgery. The catheter is inserted into the atrium of the heart toward the 
inferior vena cava. Both the the tip 16 and the root 22 should be inserted 
smoothly and quickly to minimize blood loss. The distal tip 16 is advanced 
into the inferior vena cava, thus positioning the root section 22 into the 
right atrium. This permits collection of blood from the coronary sinus and 
venous return from the superior vena cava. The webs or fins 12 at the tip 
end 26 keep the inferior vena cava open and flow will occur along the four 
sectorial channels between the fins 12. The ribs or fins 30 prevent the 
atrium from collapsing over the opening 52 in the root 22 and thus prevent 
blocking of flow. 
The area of the catheter at the root 22 and the fins 30 and 40 is sometimes 
referred to as the basket area of the cannula. With the single basket area 
in the cannula, there is no pressure drop in the open fin section and thus 
flow is significantly improved with the use of the finned section A. 
The material from which the catheter is formed is preferably a flexible 
plastic molded to the proper shape and dimensions with suitable fillets 
and no sharp corners. 
In FIG. 8, a modified form of the catheter is illustrated in which the 
insertion end is shaped such that fins 12' have a spiral shape to 
facilitate insertion and flow.