Background of the Invention
In certain types of hemodynamic systems, a pressure transducer is attached to a pressure dome that is selectively connected by valve means to either of two catheters inserted into the patient's body. In order to reduce the chances of blood particles clogging the catheters, the blood pressure is translated to the transducer by a fluid, usually a saline solution, that fills the pressure dome and the catheters. Further reduction in clogging has been achieved by introducing a slow steady flow of the fluid into the patient's body via the catheters. Even so, it has been found necessary to cause a fast flow or flush of fluid through the catheters from time to time. The means used to introduce the fast flush should be failsafe, i.e., it should permit a fast flush to occur only when it is activated by an operator. Otherwise, enough fluid might flow into the patient to cause injury or into the pressure dome to cause a false alarm of high blood pressure. Heretofore, this function has been performed by an expensive combination of a number of separate valves that can be improperly set so as to connect both catheters to the pressure dome.
Brief Discussion of the Invention
In accordance with the invention, a single valve mechanism is provided for making the desired connections between a transducer and either of the two catheters and for providing the fast flush of fluid through the connections selected. In a preferred embodiment, a cylindrical cavity is formed in a valve body and passageways within the body enter the cavity at different points within a radial plane, the arc between one point and the points on either side subtending a given angle. The outer ends of two passageways can be respectively connected to different catheters and the outer end of the third passageway can be connected to a transducer. A hollow valve stem that is closed at one end and open at the other is mounted in the cavity. Its outer surface is cylindrical and has such diameter as to provide a fluid seal against the inner wall of the cavity. A pair of openings communicate between the space inside the hollow stem and points on the cylindrical surface thereof that are in the radial plane in which the passageways enter the cavity. Communication between the openings is provided by a groove in a surface of the hollow stem, preferably in the outer cylindrical surface thereof.
An elastomeric projection is inserted into the hollow valve stem so as to block its open end and thereby provide a confined space between it and the inner walls and closed end of the hollow stem. The exterior of the projection is so shaped and has such cross-section when in a normal condition of axial stress as to block the inner ends of the openings in the wall of the hollow stem.
A channel through which flush fluid may be passed is defined in the valve body and enters the cavity in the valve body at a different point than the points of entry of the aforesaid passageways. A port is defined through the wall of the hollow stem, and means are provided for permitting communication between the port in the stem and the channel in the valve body for any desired rotational position of the stem. The elastomeric projection may or may not block the inner end of the port in the stem when in its normal condition of axial stress.
When, as has been mentioned, the projection is in its normal state of axial stress, it blocks the inner ends of the openings in the wall of the valve stem so that flush fluid entering the confined space between the outside of the projection and the inside of the hollow stem via the channel and port cannot reach the passageways. When, however, the elastomeric projection is elongated along the axis of the stem, its cross-sectional area is reduced so as to permit the flush fluid to reach the passageways. Any means can be provided for elongating the elastomeric projection in this manner but preferably it is accomplished by making the projection in the form of a hollow bladder of elastomeric material and mounting a plunger within the bladder that can be pressed so as to elongate the bladder. The plunger may extend from a cap and resilient means may be placed between the cap and the stem so as to return the plunger to its initial position when pressure is removed from the cap.
Brief Description of the Drawings
FIG. 1 is an exploded projection view of the parts of a valve incorporating the invention;
FIG. 2 is a vertical cross-section AA of an assembled valve of FIG. 1 illustrating the relationship between parts when fast flush is not being provided;
FIG. 3 is a vertical cross-section AA of an assembled valve of FIG. 1 illustrating the relationship between parts when fast flush is being provided;
FIG. 4A is a cross-section BB of FIG. 1 when the valve is assembled and not providing a fast flush;
FIG. 4B is a cross-section BB of FIG. 1 when the valve is assembled and providing a fast flush;
FIGS. 5A and 5B are the same as FIGS. 4A and 4B but illustrate a different rotational position of the valve; and
FIGS. 6A and 6B are the same as FIGS. 4A and 4B but illustrate a still different rotational position of the valve.
Reference is now made to FIGS. 1-3. The exploded view of FIG. 1 does not show the valve body, but it does illustrate a stem assembly 2, an elastomeric projection assembly 4 that will fit into a cylindrical cavity 6 in the stem assembly 2, and a cap assembly 8 having a plunger 10 that will fit into a space 11 in the elastomeric assembly 4. It is to be understood that each of the assemblies noted above may be integral parts molded from plastic.
The stem assembly 2 is comprised of an annulus 12 having a radial flange 14 extending outwardly from its top. A rim 16 having radial tongues 18 and 18' extending outwardly from opposite sides of its top is mounted on the flange 14. The tongues 18 and 18' subtend a given angle .theta., and a handle 20 extends outwardly from the rim 16. Any suitable means 22 can be attached to the bottom of the annulus 12 to retain the stem assembly 2 within the valve body at the proper axial position but, in this case, it is illustrated as having a prism 24 attached thereto for the purpose of identifying the rotational position of the stem assembly 2, as set forth in my U.S. Pat. application, Ser. No. 6/072,515, filed on Sept. 4, 1979, and entitled "Optical Valve Position Sensing".
Only a portion of a circumferential groove 26 in the outer surface of the annulus 12 is seen in FIG. 1. One end of the groove 26 communicates with an opening 28 that extends through the wall of the annulus 12 and, although not seen in this view, it communicates with a similar opening 28', shown in other views, at the other end. As will be seen in FIGS. 4, 5 and 6, the circumferential groove 26 subtends a given angle .phi. such as 90.degree..
A circumferential groove 30 similar to the groove 26 is located on the opposite side of the annulus 12 but is in a radial plane that is below the radial plane of the groove 26. At one end, the circumferential groove 30 communicates with a port 32 that extends to the inside of the annulus 12. The groove 30 subtends an angle .phi. and may communicate with a port 32', not shown, at its other end that extends through the wall of the annulus 12.
The elastomeric projection assembly 4 is comprised of a cylindrical bladder 34 in the form of an annulus that is closed at one end and defines the cylindrical space 11 therein. Surrounding the upper end of the bladder 34 is an outwardly extending radial flange 38 of such diameter as to fit within the rim 16. The upper surface of the flange 14 and the lower surface of the flange 38 are shoulders that meet so as to seal off the open end of the annulus 12 and form a confined space, except for the port 32, between the inside of the annulus 12 and the outside of the bladder 34.
A third annulus 39 that is coaxial with the annulus 12 extends upwardly from the top of the flange 38. Its inner diameter is greater than that of the cylindrical space 11, and its outer diameter is less than that of the flange 38.
The cap assembly 8 is comprised of a disc 40 having a rim 42 extending below it. The inner diameter of the rim 42 is enough greater than the outer diameter of the rim 16 of the stem assembly 2 to provide a slide fit therewith. The rim 42 has apertures 44 on opposite sides thereof, only one of which can be seen in FIG. 1, each aperture subtending an angle .theta. and having a height that is greater than the height of the tongues 18 and 18'. A slot 46 in the rim 42 is of such size as to fit over the handle 20 and is located to do so when the tongues 18 and 18' of the stem assembly 2 extend through the apertures 44 of the cap assembly 8. The plunger 10 extends downwardly from the center of the disc 40 and is of such diameter as to fit into the space 11 in the projection assembly 4.
Complete Assembly and Operation
FIGS. 2 and 3 are vertical sections taken at AA of FIG. 1 when the valve is completely assembled and the annulus 12 is mounted within a cavity 48 in a valve body 50. As seen in FIGS. 4A and 4B, which are horizontal cross-sections taken at BB of FIG. 1 when the valve is completely assembled and mounted in the cavity 48, the valve body 50 defines a passageway DL that may be connected to a distal lumen, a passageway PL that may be connected to a proximal lumen, and a passageway T that may be connected to a transducer. All these passageways enter the cavity 48 at the same radial plane as the circumferential groove 26 of FIG. 1. One end of the groove 26 communicates with the opening 28, as also seen in FIG. 1, and the other end with an opening 28', not seen in FIG. 1, that extends to the inside of the annulus 12. Also defined within the valve body 50 is a channel 52 that enters the cavity 48 within the same radial plane as the circumferential groove 30 of FIG. 1. One side of the groove 30 communicates with the port 32 shown in FIG. 1 and the other end with a port 32', not shown in FIG. 1, that extend through the wall of the annulus 12. The channel 52, the circumferential groove 30 and the ports 32 and 32' are shown in dotted lines in FIGS. 4A and 4B. In FIG. 2 and FIG. 3, only the channel 52 and the passageway T are in direct view. The entry of the passageway DL is indicated by a dotted circle. Because the passageways, channel and grooves have a finite size, they obviously enter the cavity 48 between two separated radial planes, but a single radial plane is referred to for simplicity of language. When referring to an angle subtended between points at which openings or passageways enter a portion of the structure, the angle between their centers is intended.
In FIGS. 4A and 4B, the stem assembly 2 is oriented within the cavity 48 of the valve body 50 as depicted in the vertical cross-sections of FIGS. 2 and 3 respectively wherein, as indicated by the arrow, the handle 20 lies directly over the point at which the channel 52 enters the cavity 48. In this position, the passageway T is not connected to any other passageway. In FIG. 4A and in FIG. 2, the cap assembly 8 is not depressed so that the bladder 34, which is the elastomeric projection in this specie of the invention, is in its normal condition of axial stress and blocks the openings 28 and 28'. When, however, the cap assembly 8 is depressed, as shown in FIGS. 3 and 4B, the annulus 39 is deformed and the plunger 10 elongates the bladder 34 so as to reduce its cross-section and unblock the openings 28 and 28'. In some designs, the bladder 34 may also block the point where the ports 32 and 32' enter the cavity 6 inside the annulus 12, as shown in FIG. 2, but this is not necessary. In either case, flush fluid supplied to the channel 52 will pass through the groove 30 and the ports 32 and 32' into the enlarged space 54 that is between the inner surface of the annulus 12 and the outer surface of the bladder 34. From there it can reach the passageway T via the openings 28 and 28' and the groove 26, and provide a fast flush to a transducer connected to the passageway T.
It will be apparent that the function of the circumferential groove 30 is to connect the port 32 to the channel 52 regardless of the rotational position of the valve stem assembly 2. It is also apparent that either port 32 or 32' may be eliminated, but this could entrap air bubbles.
FIG. 5A illustrates the cross-section BB when the rotational position of the handle 20 is such that the proximal lumen channel PL is connected to the transducer channel T via the circumferential groove 26 so that the blood pressure in the proximal lumen may be measured. When the cap assembly 8 is depressed, as illustrated by FIG. 5B, the fast flush fluid will reach the selected passageways PL and T so as to flush both the proximal lumen and the transducer.
In FIG. 6A, the rotational position of the handle 20 is such as to connect the distal lumen channel DL to the transducer channel T. Both channels will be fast-flushed as indicated in FIG. 6B when the cap assembly 8 is depressed.
It will be apparent that with both ports 32 and 32' present, the circumferential groove 30 can be eliminated and replaced by a circumferential groove in the inner surface of the cavity 48 that subtends an angle of 90.degree. in either direction from the point of entry of the channel 52, e.g., a groove as indicated by the dashed line 56 in FIGS. 4A and 4B. In any rotational position of the handle 20, the flush fluid can reach one of the ports 32 or 32'.
Although the passageways T, DL and PL in the valve body 50 are shown as entering the cavity 48 in a radial plane, they could enter the cavity 48 at points that do not lie in a radial plane as long as they can be made to communicate with openings in the annulus 12 that are joined by a groove in either the inner or outer surfaces of the annulus 12.
Only one of the openings 28 and 28' are required to permit flushing fluid to flow into the groove 26 and into the passageways with which the groove communicates, but having only one opening would permit the entrapment of air.
If it is desired that the fast flush be available only during predetermined rotational positions of the valve assembly, the port means could be comprised of a port or ports extending through the wall of the annulus 12 at such point or points as to provide communication between the channel 52 and the space inside the annulus 12 when the valve assembly is in these positions. This would permit the elimination of the grooves 30 and/or 56.