Rotary valve especially useful in a medical system including a flow-directed venous catheter

A rotary valve, especially designed for use in medical systems, has an arrangement of passageways in its rotary valve plug and ports in its housing that permit manual manipulation of the valve to switch the medical system from monitoring pulmonary artery pressure to measuring central venous pressure. The system can also be used for cardiac output measurement or for the withdrawal of a mixed venous blood sample. Patient trauma and contamination are avoided.

FIELD OF THE INVENTION 
This invention is concerned with a rotary valve construction that is 
generally useful with liquids and gases. More particularly, the valve is 
especially useful in connection with the administration of medications and 
intravenous fluids and the measurement of pressures within the body. 
BACKGROUND OF THE INVENTION 
The use of the flow-directed balloon-tipped pulmonary artery catheter is 
now well established in clinical practice. It was initially described in 
1970 in the important paper by Swan, Ganz et al., "Catheterization of the 
Heart in Man with Use of a Flow-Directed Balloon-Tipped Catheter", New 
England Journal of Medicine (N.E.J.M.), 283, 447-451. 
The uses for this device range from the management of critically ill 
patients in the Intensive Care Unit to the monitoring of patients for 
open-heart surgery, diagnostic cardiac catheterization, and research 
applications. The device can be used to measure central venous, pulmonary 
artery and wedge pressures. 
The Swan-Ganz catheter equipment and the accessories often employed with it 
are described in many medical publications, including, for example, the 
following: 
Anaesthesia 34, 651-656 (1979), "The Swan-Ganz Pulmonary Artery Catheter", 
and Anesthesiology 45, 146-155 (1976), "Hemodynamic Monitoring: Invasive 
Techniques". 
In the operating room and in the intensive care area, the Swan-Ganz, 
balloon-tipped, pulmonary artery thermodilution catheter is often used for 
the measurement for intracardiac, intraarterial, and intravenous 
pressures. Often this use is combined with use for the administration of 
intravenous fluids and medication. For these purposes, the catheter 
generally is provided with a thermistor sensor, a distal lumen for 
pulmonary artery pressure measurement (the lumenal opening generally being 
at the tip), a proximal lumen generally located about 30 cm from the 
distal lumen for central venous pressure measurement, and a balloon tip 
for flow directing. This catheter has become standard for the care of 
patients with medical histories demanding the careful regulation of fluid 
balance and for the measurement of cardiopulmonary performance in the 
operating room and in intensive care. 
To use the catheter, it is inserted percutaneously, generally with the 
assistance of an introducer cannula. The distal lumen is connected with a 
pressure transducer for monitoring the pulmonary artery pressure. The 
distal lumen can also be used for mixed venous blood sampling. If so 
designed, it can be used for the measurement of cardiac output by the 
thermal dilution principle. It can also be used for the administration of 
drugs or agents likely to cause phlebitis or which it is desirable to 
direct in a concentrated form into the heart or great vessels. 
The prevention of blood clots in the catheter system is achieved by 
continuously flushing both lumens with sterile solution. This is usually 
accomplished by the connection of intravenous fluids to the proximal lumen 
port and the distal lumen port to the transducer flush system. A schematic 
diagram illustrating the technique for connecting the transducer appears 
in the article in N.E.J.M., supra. 
In addition, fluid may be injected into the proximal lumen for the 
determination of cardiac output by the thermal dilution method, and blood 
may be withdrawn from the distal lumen for the determination of 
intrapulmonary shunt fraction. Such data as the pressure measurements 
referred to, cardiac output, intrapulmonary shunt, and body temperature 
are utilized for the diagnosis and treatment of conditions arising in the 
operating room and in the intensive care unit. 
In current practice, since the central venous pressure measurement is 
required less frequently than the pulmonary artery pressure measurement 
from the distal lumen, a single transducer is commonly connected to the 
distal lumen and a single intravenous solution is connected to the 
proximal lumen. When the central venous pressure is to be measured, the 
transducer tubing is disconnected from the distal lumen, both parts being 
held in the hands, and the intravenous tubing is also disconnected from 
the proximal lumen, these tubings being placed on the patient's bed. The 
tubings are then reversed, the intravenous solution being connected to the 
distal lumen, the transducer being connected to the proximal lumen, and 
central venous pressure then being measured. The process is reversed to 
establish the original conditions. 
In addition, it is common practice to place additional stopcocks and tubing 
in the system, to permit the injection of fluid for cardiac output 
measurement, and for sampling of blood for intrapulmonary shunt 
determination. These stopcocks are known to be sites of contamination of 
catheter systems, Anesthesia and Analgesia, 55, 141-142 (1979), "Stopcock 
Contamination". There is always a risk of malpositioning one of the 
stopcocks, a risk of the entry of air into the system, or of the 
production of blood clots in the catheter, rendering the catheter 
non-functional and subjecting the patient to the substantial risks of 
catheter replacement which include ventricular extrasystoles, heart block, 
ventricular fibrillation, intracardiac knotting, balloon rupture, thrombus 
formation and pulmonary infarction, perforation of the pulmonary artery, 
and infection, Anaesthesia, 33, 172-177 (1978), "Hazards of Central Venous 
Pressure Monitoring". In addition, the catheter should be firmly stitched 
in place, and all devices attached to it preferably should have locking 
hubs. 
At present, there is no available valve design which permits these 
measurements, injections or sampling to be made through the operation of a 
valve, simply, safely, and with the necessary degree of sterility. 
Accordingly, each time a reversal of the tubings is done, the patient is 
placed at significant risk for the introduction of bacteria into the 
catheter and consequent bacteremia, sepsis, and endocarditis. When an 
array of stopcocks and tubing is used, the arrangement is often baffling, 
even to its designer, leading often to confusion and sometimes to errors 
on the part of personnel who must monitor the patient and use the 
arrangement on a 24 hour per day basis, especially when the designer of 
the arrangement is not at hand to explain it. Seldom are these 
arrangements uniform in structure or function, so that each requires study 
and sometimes experimentation. All of these considerations can generate 
potentially life-threatening complications for the patient. 
In the intensive care area and in the operating room, such procedures may 
be repeated up to 30 times per day per patient, thus exposing the patient 
many times to these risks. 
SUMMARY OF THE INVENTION 
The invention is a rotary valve that is especially designed for certain 
medical applications. However, the valve has general utility wherever 
certain types of flexibility are needed in interconnecting different lines 
of fluid communication. 
The rotary valve of the invention comprises a housing having a bore 
extending partly therethrough. This bore is bounded by a surface of 
revolution. The housing has a plurality of ports opening into the bore 
through the side wall of the housing. These ports are disposed in 
cooperating pairs, each pair of ports being spaced from each other pair of 
ports. 
A valve plug is movably mounted in the bore of the housing for rotary 
movement therein. This plug is formed with passageways, positioned so that 
in one orientation of the plug within the housing, the passageways are in 
communication with the pairs of ports respectively in the housing, to 
place each port in communication with the other cooperating member in its 
pair respectively. 
In a preferred embodiment of the invention, the pairs of ports are axially 
spaced of the housing bore, relative to each other, and there are 
transversely-extending passageways that correspond in number to the number 
of pairs of ports. 
The valve plug is also formed with other passageways therein that are 
disposed, upon proper orientation of the plug in the housing by rotation 
thereof, each to be in communication with one port of one pair of ports 
and with another port from another pair of ports, respectively, to 
establish communication between these thus-connected ports. Preferably 
these other passageways are in the form of a plurality of channels in the 
surface of revolution of the plug. These channels are formed so they can 
provide communication, respectively, upon proper orientation of the plug, 
between one port of one pair of ports and a second port from a different 
pair of ports. 
According to another preferred embodiment of the invention, the valve plug 
is formed with an exposed outer face and with an additional passageway 
that extends partly axially through the plug from said outer face, and 
partly transversely through the part of the plug that is within the bore 
of the housing, opening upon the surface of revolution of the plug. The 
transverse portion of this passageway is positioned so that upon proper 
orientation of the plug within the housing, the transverse portion of this 
passageway is placed in communication with one of said ports in the 
housing, and the remaining ports are sealed closed by the surface of the 
plug. 
Most preferably, there are two such additional passageways within the plug, 
the two passageways having different axial extents, so that one of these 
additional passageways is available for communication with one pair of 
ports, and the other additional passageway is available for communication 
with another pair of ports. 
For medical applications, all parts are formed to be readily sterilizable, 
and for quick connection and disconnection of tubing, and an easily 
detachable cap is provided to close each opening in the exposed outer face 
of the plug, to facilitate the maintenance of sterile conditions. 
In a preferred medical application of this valve, it is used in a medical 
system that includes: a flow-directed intravenous catheter having a distal 
lumen and a proximal lumen; a pressure transducer; and an infusion device. 
The rotary valve is so designed and the system is so connected that when 
the valve plug is oriented to place the ports in each pair of ports in 
communication with each other respectively, through the transversely 
extending passageways in the plug, the ports of one pair of ports are in 
communication with the proximal lumen and the infusion device 
respectively, and the ports in the other pair of ports are in 
communication with the distal lumen and with the pressure transducer, 
respectively. Upon rotation of the valve plug to make use of the channels 
in the surface of the plug, rather than the transversely extending 
passageways therethrough, one channel serves to establish communication 
between the proximal lumen and the pressure transducer, and the other 
channel establishes communication between the distal lumen and the 
infusion device. 
It is also possible to orient the plug to establish communication between 
one port in the exposed outer face of the plug and the proximal lumen, all 
other ports being sealed closed. This permits the injection of fluid 
through the port in the exposed outer face of the valve plug, for use in a 
procedure such as a cardiac output measurement. 
In a different orientation of the valve plug, communication can be 
established between another port in the exposed outer face of the valve 
plug and the distal lumen, with all other ports being sealed off and out 
of service. This permits the removal of a blood sample and is useful in a 
procedure such as the taking of a mixed venous blood sample.

DETAILED DESCRIPTION OF THE INVENTION 
Referring now in detail to the drawings by numerals of reference, the 
numeral 10 denotes generally the housing for the rotary valve. This 
housing is a generally cylindrical body having two ports 11 and 12 
respectively, that are arranged in axial alignment. Each of these ports 11 
and 12 is equipped as a male, hooded Luer fitting. The housing is also 
provided with two other ports 13 and 14, respectively, which are in 
diametric opposition to the first-named ports 11 and 12. The ports 13 and 
14 are each formed as female Luer fittings. The Luer-type fittings are 
standard fittings in use in medical equipment for quick but fluid-tight 
connection with tubing. 
The housing 10 is also formed with a generally cylindrical bore 16, that 
extends partly through the housing. The bore is thus bonded by a generally 
cylindrical wall 17 of the housing, and by the closed end 18 of the 
housing. 
The housing wall 17 is formed, just within the open end of the bore 16, 
with a groove 19, for receiving a resilient retainer ring or an O-ring, as 
will be described presently. 
Turning now specifically to FIGS. 4-7 inclusive, the numeral 20 denotes 
generally the valve plug. The plug 20 is formed with a generally 
cylindrical shape. It has a section 21 that is insertable within the 
housing bore 16, as will presently be described. The plug also has another 
section 22 that, upon assembly of the two valve parts, projects out of the 
housing. These two sections 21 and 22 are of different diameters and are 
separated from each other by a shoulder 24 that, upon assembly, abuts 
against the end of the housing to limit the travel of the insertable 
section 21 into the bore of the housing. 
In its insertable section 21, the valve plug is formed with a pair of 
diametrically-extending passageways 25 and 26 respectively, that are 
spaced from each other axially of the plug, and that are located to be in 
registry with the pairs of ports in the housing 11 and 13, and 12 and 14, 
respectively. 
The insertable section 21 of the valve plug is also formed to have a 
generally cylindrical surface designed to confront and engage against the 
inner surface 16, in fluid-tight fashion. The plug is formed in this 
surface with a pair of generally helical channels 27 and 28 respectively. 
These channels have the same pitch, and the midpoint of each is 
diametrically opposed to the midpoint of the other. Each channel has at 
one end a generally circular termination that is disposed to be in 
transverse registry, upon assembly of the valve, with the housing ports 11 
and 13, and each has at its opposite end a generally circular termination 
that is in registry respectively with the ports 12 and 14 of the housing. 
As best shown in FIGS. 4 and 5, the ends of these channels are angularly 
spaced from the openings of the two diametrically-extending passageways 25 
and 26 respectively, by 90.degree.. 
The insertable section 21 of the plug is also formed with a resilient, 
compressible detent 30, which seats in the groove 19 in the surface of the 
bore of the housing. Instead of an integral detent 30, an O-ring may be 
used but is less preferred. The function is to permit snap assembly of the 
valve. 
The valve plug is also formed with a pair of additional passageways 31 and 
32 respectively. These passageways extend primarily axially along the 
length of the plug. 
The passageway 31 opens onto the exposed outer face 34 of the plug to 
provide a port 35. This passageway 31 extends axially of the plug for 
almost the entire length of the plug, then has a right-angled extension 36 
that extends transversely of the plug to open through the cylindrical plug 
face to provide a port 37. The passageway extension 36 and port 27 have an 
axis that falls in the same plane as the axis of the transversely 
extending passageway 26. 
Similarly, the additional passageway 32 opens through the outer face 34 of 
the plug to provide a port 38. This additional passageway 32 extends 
axially through the body of the plug until it intersects the plane of the 
axis of the transversely-extending passageway 25. At that point, it has a 
transverse extension 39 that opens through the cylindrical surface of the 
plug to provide a port 40. 
As shown in FIGS. 8 and 10, the valve plug is formed with an integral 
closure cap that is generally denoted by the numeral 41. This cap is 
connected to the body of the valve plug through a split hinge 42. The 
closure cap 41 has two separately operable halves or flaps 44 and 45. 
These closure flaps are each formed with plugs 46 and 48 respectively, 
that are shaped for insertion in the ports 35 and 38, to close them. Each 
plug is formed with a resilient detent ring 57, for seating engagement in 
a recess 58 that is formed in the surface of each of the ports 35 and 38 
respectively. 
Upon insertion of the valve plug into the housing, the assembly shown in 
FIGS. 8-10 inclusive is obtained, the split closure cap 41 being shown in 
its closed position. 
As shown in FIG. 8, the housing carries thereon three indicator marks, 50, 
51, and 52. The indicator mark 50 is accompanied by the legend, 
"PROXIMAL". The indicator mark 51 is accompanied by the legend, "CARDIAC 
OUTPUT". The indicator mark 52 is accompanied by the legend, "DISTAL". 
These three indicator marks are angularly spaced from each other about the 
periphery of the valve housing as shownn in FIG. 8. Still referring to 
FIG. 8, the projecting section 22 of the valve plug carries an indicator 
mark 54. In FIG. 8, the valve plug is oriented with the DISTAL indicator 
mark 52 and the plug indicator mark 54 in alignment. 
As shown in FIG. 10, the other face of the housing is also provided with an 
indicator mark 56, which is accompanied by the legend "MIXED VENOUS". 
Referring to FIG. 9, the flap 44 of the closure cap 41 carries the legend 
"CARDIAC OUTPUT". The other flap 45 of the closure cap carries the legend, 
"MIXED VENOUS". 
The preferred embodiment of the invention, described above, is well suited 
for use in connection with a flow-directed, balloon-tipped pulmonary 
artery catheter, of the kind described in the publication by Swan, Ganz et 
al., N.E.J.M., supra. Generally such a system will include: a 
flow-directed intravenous catheter having a distal lumen and a proximal 
lumen; a pressure transducer with a continuous flush device; and an 
infusion device. 
In such a medical system, the normal orientation of the rotary valve plug 
is as shown diagrammatically in FIG. 11. The female Luer-type connections 
(not shown) to the proximal lumen and the distal lumen of the catheter are 
mated with the male Luer-type connections 11 and 12 of the valve housing. 
Thus, the proximal lumen of the catheter is connected to the male port 11, 
and its distal lumen is connected to the male port 12. The pressure 
transducer is connected, preferably by high pressure flush tubings, to the 
female Luer-type port 14 of the valve housing. An infusion device, for the 
maintenance of patency, or for the administration of fluids through the 
proximal lumen of the catheter, is attached to the female Luer-type port 
13 of the valve housing. 
In use of the valve, when the indicator line 54 on the projecting section 
22 of the valve plug is aligned with the DISTAL datum line 52 on the valve 
housing (FIG. 8), then the distal lumen of the thermodilution catheter 
(which is connected to the port 12) communicates with the pressure 
transducer (which is connected to the port 14) through the 
transversely-extending passageway 26, as shown in FIG. 11, so that the 
pulmonary artery pressure can be monitored by the pressure transducer. 
Still referring to FIG. 11, the infusion device is connected to the port 
13 and communicates through the line 25 and port 11 with the proximal 
lumen of the catheter, so that the patency of the proximal lumen may be 
maintained. All other pathways are occluded in this orientation. 
Referring now to FIG. 12, when measurements of pressures in the proximal 
lumen of the catheter are required, such as central venous pressure, the 
valve plug is rotated within the valve housing 90.degree. from the 
position shown in FIG. 8, to align the indicator mark 54 on the valve plug 
with the PROXIMAL mark 50 on the valve housing. In this orientation, the 
transversely-extending passageways 25 and 26 respectively are occluded. 
The proximal lumen of the catheter is in communication with the pressure 
transducer through the port 11, the helical channel 27, and the port 14. 
Similarly, the infusion device communicates with the distal lumen of the 
catheter through the port 14, the helical channel 28, and the port 12, and 
patency in the distal lumen of the catheter is assured. When the 
measurements are completed, the valve plug can be returned to its initial 
position shown in FIG. 8, so that the distal lumen (pulmonary artery 
pressure) is returned to communication with the pressure transducer as 
shown in FIG. 11. 
When it is desired to perform a cardiac output measurement, the valve plug 
is rotated 45.degree. within the housing from the position shown in FIG. 
8, to align the indicator mark 54 on the valve plug with the CARDIAC 
OUTPUT indicator mark 51 on the housing. At this orientation, the 
transversely extending passageways 25 and 26 are occluded; the helical 
channels 27 and 28 are occluded; and the port 40 of the extension 39 of 
the axially-extending passageway 32 in the valve plug is aligned with the 
port 11 of the housing and, thus, the axially-extending passageway 32 is 
in communication with the proximal lumen of the catheter. By lifting off 
the closure flap 44, a syringe may be inserted in the port 38 in the outer 
face 34 of the plug, and fluid may be injected into the axially extending 
passageway 32 for passage to the proximal lumen of the catheter. 
When the injection has been completed, the cap 44 and its plug 46 may be 
cleaned and then the closure plug 46 may be snapped back into the port 38 
to seal off the passageway 32. After the cardiac output measurement 
procedure has been completed, the valve plug may be rotated in the housing 
to return it to the position shown in FIGS. 8 and 11. 
Referring now to FIG. 14, when it is desired to obtain a mixed venous blood 
sample from the distal lumen of the catheter, the valve plug is rotated 
until the mark 54 is aligned with the MIXED VENOUS line 56 (FIG. 10). In 
this orientation of the valve plug, the transversely extending passageways 
25 and 26 are occluded. The helical channels 27 and 28 are occluded; and 
the port 37 in the cylindrical surface of the insertable section 21 of the 
valve plug is aligned with the port 12 in the housing, thus placing the 
axially extending passageway 31 in communication through the port 12 with 
the distal lumen of the catheter. By lifting off the closure flap 45, a 
syringe may be inserted through the port 35, to permit removal of a blood 
sample. 
Because blood remains in the axially-extending passageway 31 after the 
blood sample has been removed, a flushing operation is necessary. To 
accomplish this, the valve plug is rotated through 180.degree. until the 
indicator mark 54 is aligned with the CARDIAC OUTPUT mark 51. In this 
position, the port 37, that opens in the cylindrical surface of the valve 
plug, is aligned with the port 14 in the housing, the axially-extending 
passageway 31 may be flushed using the transducer flush, the line of 
communication being that shown in FIG. 13. The closure flap 45 should then 
be cleansed, and the closure plug 48 can then be inserted in the port 35 
again. The valve plug is then rotated to return it to the position shown 
in FIG. 8. 
Advantages 
A valve constructed in accordance with the foregoing preferred embodiment 
of the invention has many advantages for use in medical applications. It 
can be fabricated from a synthetic plastic, and the cost is sufficiently 
low so that it is disposable. It is also readily sterilizable. 
The valve is manually operated. It can be formed, as illustrated in the 
drawings, with male and female Luer and Linden fittings, which are in 
standard use on current medical pressure monitoring and fluid 
administration lines. 
Another important advantage of the valve is that it provides the capability 
of switching to fluid lines along simple, direct, small volume pathways to 
eliminate the potential for the formation of air bubbles and to minimize 
abrupt directional changes. The presence of air bubbles in a catheter line 
can significantly alter frequency response and pressure accuracy. 
Reference, Anesth. 53, 498-504 (1980), "The Dynamic Responses of 
Liquid-Filled Catheter Systems for Direct Measurement of Blood Pressure". 
If the valve housing is constructed of a clear, transparent synthetic 
plastic, visual inspection can be used to detect the presence of air 
bubbles in the less direct pathways. Severe direction changes can 
adversely affect and alter frequency response. 
Particularly when compared to present techniques, use of the valve 
simplifies procedures, increases reliability, and greatly minimizes the 
potential for contamination. Use of the valve decreases the time required 
to perform volume-flow measurements, pressure measurements, fluid 
injections, and fluid samplings. In addition, the valve provides an 
injection port through which liquid can be injected into a low volume 
pathway which is in communication with an easily selected outlet port. The 
visual signals on the valve itself minimize the opportunity for error. The 
occlusion of ports not in use, through proper orientation of the valve, 
protects the transducer and insures the use of the correct volume for 
injection when cardiac output is measured. 
The valve also provides a blood sampling port that communicates with a low 
volume pathway. This low volume pathway in turn is in communication with 
the appropriate port in only one orientation of the valve plug in its 
housing. 
The separate flaps on the closure cap occlude and protect the injection and 
blood sampling ports. Since they may be molded with and integral with the 
valve plug, their presence in the device greatly minimizes the potential 
for contamination. 
The valve also provides the ability to flush residual blood from the blood 
sampling port using the transducer flush, thus preventing clotting and 
subsequent occlusion of the port. While flushing, all uninvolved ports in 
the valve are occluded. 
While offering many advantages, the structure of the valve involves the use 
of only two parts. Preferably, the housing is formed from a clear 
synthetic resin, and the valve plug is opaque, formed of a resilient, 
compressible material with an integral closure cap. If the ring 30 is made 
integral with the valve plug, the use of an O-ring being eliminated, 
sterilization is facilitated. 
Three Channel, Eight Port Valves 
There are situations in the operating room and in the surgical intensive 
care setting where it is desirable to monitor a thermodilution catheter, 
with its proximal and distal ports, as well as an arterial line for blood 
pressure, utilizing one or more pressure transducers. The basic principles 
of the present invention, discussed above in connection with one 
embodiment of the invention wherein the rotary valve has two channels and 
six ports, can be incorporated in another preferred embodiment of the 
invention in which the valve has three channels and eight ports. 
Referring now in detail to FIGS. 15-21 by numerals of reference, like 
numerals, primed, have been applied to parts of this valve that are 
essentially similar to the valve shown in FIGS. 1 through 10 inclusive. 
Structural descriptions that are obvious from the earlier drawings and 
description are not repeated. 
The housing 10' is provided with an additional male Luer-type port 54, and 
an additional female Luer-type port 55. These two ports are not 
diametrically opposed as is the case with the other ports of this valve 
housing. 
The insertable section 21' of the valve plug 20' is formed with a pair of 
diametrically-extending passageways 25' and 26' respectively. It is also 
formed in its generally cylindrical surface with three primary helical 
channels. A first helical channel 67 is disposed so that, upon proper 
orientation of the plug within the housing, it can provide communication 
between the ports 12' and 55 of the housing. A second helical channel 68 
is formed so that upon proper orientation of the plug in the housing, it 
provides communication between the ports 11' and 55 respectively. The 
third helical channel 69 is so formed that upon proper orientation of the 
plug in the housing, it provides communication between the ports 11' and 
14'. 
The insertable section 21' of the valve plug is also formed with a 
diametrically extending, passageway 64 (FIGS. 16 and 17), which in the 
assembled valve, has an axis that is aligned with the axis of the port 54. 
The plug section 21' is also formed in its cylindrical face with a short 
channel 65 that communicates with the passageway 64, and that, upon proper 
orientation of the plug, provides communication between the port 55 and 
the passageway 64, to permit communication of the passageway 64 with the 
port 54. 
The plug section 21' is also formed with a helical channel 66 that is 
formed so that upon proper orientation of the plug in the housing, the end 
of the channel 66 furthest inserted in the housing communicates with the 
port 55. The other end of the channel 66 communicates with a port 70 to be 
described presently. 
The valve plug is also formed with a pair of axially extending passageways 
74 and 75. The passageway 74 opens through a port 72 in the outer face 34' 
of the plug. At its other end, the passageway 74 has a short, transversely 
extending section that opens through a port 71 that is transversely 
aligned to be in the same plane as the axis of the ports 11' and 13'. The 
passageway 75 opens through the outer face 34' of the plug through a port 
73, and at its other end has a short transverse extension that opens on 
the cylindrical surface of the plug to provide the port 70. 
The insertable section 21' of the valve plug is also formed with a curved 
channel 80 (FIG. 17) in its generally cylindrical surface. This channel 80 
is formed so that upon proper orientation of the valve plug, it provides 
communication between the port 14' and the port 12'. 
Referring now to FIG. 19, the surface of the external section 22' of the 
valve plug is provided with an indicator mark 81. The surface of the 
housing 10' is provided with several cooperating indicator marks, namely a 
CARDIAC OUTPUT mark 82, a MIXED VENOUS FLUSH mark 83, an ARTERIAL mark 84, 
a PROXIMAL/CVP mark 85, and a DISTAL mark 86. Referring to FIG. 21, the 
other side of the housing 10' is provided with a MIXED VENOUS mark 87. 
Referring to FIG. 20, the closure cap flap 44' is provided with indicia, 
"CARDIAC OUTPUT", and the other closure cap flap 45' is provided with 
indicia, "MIXED VENOUS". 
This three channel, eight port valve is particularly intended for use in a 
medical system where there is a flow-directed, balloon-tipped pulmonary 
artery catheter having a distal lumen and a proximal lumen, with ports; 
two infusion devices; a pressure transducer; and an arterial line. With 
the use of the valve just described, having three primary helical channels 
and eight ports, this system can be arranged to permit the monitoring of 
arterial pressure, the monitoring of pulmonary artery pressure, the 
monitoring of central venous pressure, withdrawal of a mixed venous 
sample, and, when the catheter is a thermodilution catheter, the 
measurement of cardiac output, all without disturbing any connection to 
the patient, through the use of the valve as a switching device. 
Ordinarily in such a system the arterial line would be monitored most of 
the time. The normal arrangement would be that shown in FIG. 22. In this 
arrangement, the indicator mark 81 on the projecting end 22' of the valve 
plug is aligned with the ARTERIAL indicator mark 84 on the housing 10'. 
The arterial line is connected to the male Luer-type port 54, which is 
aligned with the transversely-extending passageway 64 and its extension 
groove 65. The arterial line thus communicates through the port 54, the 
passageway 64, groove 65, and the female Luer-type port 55, which 
communicates with the pressure transducer. The distal port of the catheter 
is connected to the port 12', which communicates through the 
diametrically-extending passageway 26' through the valve plug, and the 
port 14', with an infusion device. The proximal lumen or port of the 
catheter is connected through the port 11', the generally 
diametrically-extending passageway 25', and the port 13', with an infusion 
device. All other ports and grooves or channels of the valve plug are 
occluded. 
In this arrangement, the arterial line is thus in communication with the 
pressure transducer, to permit the arterial pressure to be monitored. 
In order to monitor the distal port of the thermodilution catheter for 
pulmonary artery pressure, the valve plug is rotated 90.degree. from the 
FIG. 22 position, just described, so that the indicator mark 81 on the 
valve plug is aligned with the DISTAL mark 86 on the housing. Then, as 
shown in FIG. 23, the port 54 is occluded. The port 54 communicates with 
the arterial line and its occlusion prevents any high pressure bleed-back 
into the valve. The distal port of the catheter is connected to the port 
12' and communicates through the helical channel 67 and the port 55 with 
the pressure transducer. The proximal port of the catheter communicates 
through the port 11', the helical channel 69, and the port 14', with an 
infusion device. All other grooves and ports on the valve plug are 
occluded, as are the ports 54 and 13' of the housing. When the 
measurements have been completed, the valve plug can be returned to its 
initial (FIG. 22) position, with the indicator mark 81 on the valve plug 
aligned with the ARTERIAL mark 84 on the housing, so that the arterial 
line pressure can be monitored. In situations where there is no arterial 
line, the valve plug can be left in the position shown in FIG. 23, where 
the indicator line 81 on the valve plug is aligned with the DISTAL mark 86 
on the housing. 
To monitor the proximal port of the catheter for central venous pressure, 
the valve plug is rotated within the housing until the indicator mark 81 
is aligned with the PROXIMAL/CVP mark 85. As shown in FIG. 24, this again 
occludes the port 54 attached to the arterial line, preventing high 
pressure bleed-back into the valve. In this arrangement, the proximal port 
of the catheter is connected to the pressure transducer through the port 
11', the helical channel 68, and the port 55. The distal port communicates 
through the port 12', the curved channel 80, and the port 14', with an 
infusion device. All of the other ports and channels are occluded. When 
measurements have been completed, the valve plug can be returned to its 
normal (FIG. 22) position, that is, with the indicator mark 81 on the 
valve plug aligned with the ARTERIAL mark 84. 
This type of rotary valve can also be used in a slightly different medical 
system where a flow-directed, balloon-tipped catheter is used without an 
arterial line. In this configuration, the indicator mark 81 is aligned 
with the DISTAL mark 86 on the housing. As shown in FIG. 25, this occludes 
the port 54 which is not in use. In this arrangement, the distal port of 
the catheter is connected to the pressure transducer through the port 12', 
the helical channel 67, and the port 55. The proximal port communicates 
through the port 11', the helical channel 69 and the port 14', with an 
infusion device. All other ports and channels are occluded. When it is 
desired to monitor the central venous pressure, the valve plug is rotated 
until the indicator mark 81 is aligned to the PROXIMAL/CVP mark 85. As 
shown in FIG. 26, in this arrangement, the proximal port of the catheter 
is connected to the pressure transducer through the port 11', the helical 
channel 68, and the port 55. The distal port communicates through the port 
12', the curved channel 80, and the port 14', with an infusion device. All 
other ports and channels are occluded. When measurements have been 
completed, the valve plug can be returned to its normal (FIG. 24) position 
for this configuration with the indicator mark 81 on the valve plug 
aligned with the DISTAL mark 86. 
This type of rotary valve can also be used in a slightly different medical 
system. As shown in FIG. 27, the port 11' can be connected to a CENTRAL 
VENOUS PRESSURE monitor line, and the port 54 can be connected to an 
arterial line. With the rotary plug adjusted so that the indicator mark 81 
on the valve plug is aligned with the ARTERIAL indicator line 84, the 
infusion device is connected to the port 13', and there is communication 
through this port with the diametrically extending passageway 25' and the 
port 11', to permit infusion of the central venous pressure line. The 
arterial line is connected to the port 54 and communicates through it with 
the diametrically extending passageway 64, the groove 65, and the port 55, 
thus placing the arterial line in communication with the pressure 
transducer to permit monitoring of arterial pressure. The port 14' and the 
port 12' communicate through the diametrically-extending passageway 26', 
but both of these ports are out of service. 
To measure the central venous pressure with this particular medical system, 
the valve plug is rotated within the housing until the indicator mark 81 
on the plug is aligned with the PROXIMAL/CVP mark 85 on the housing. In 
this orientation, as shown in FIG. 28, the central venous pressure line 
communicates with the port 11', through the helical channel 68, and the 
port 55, with the pressure transducer. This permits measurement of the 
central venous pressure. The arterial line is occluded, as are all other 
ports and channels, except the curved channel 80 which interconnects the 
ports 12' and 14', which in any case are not in service. 
After the central venous pressure has been measured, the valve plug is 
rotated to return it to its normal (FIG. 27) position for this particular 
medical system, with the indicator mark 81 on the valve plug aligned with 
the ARTERIAL indicator mark 84 on the housing. 
When this particular embodiment of the valve of the invention is employed 
in a medical system including a thermodilution catheter, some features and 
advantages arising through the use of the valve can be illustrated by 
reference to FIG. 29, which illustrates the measurement of cardiac output. 
For this purpose the indicator mark 81 on the valve plug is aligned with 
the CARDIAC OUTPUT indicator mark 82 on the housing. Then, as shown in 
FIG. 29, the proximal port of the catheter communicates through the port 
11' of the housing, the port 71, and the axially-extending passageway 74 
in the valve plug, with the port 72 in the outer face 34' of the valve 
plug. The closure cap flap 44' is then lifted off the outer face 34' of 
the valve plug, removing the closure plug 46' from the port 72. The 
necessary injection can then be made through the port 72 into the 
axially-extending passageway 74, for passage through the ports 71 and 11' 
into the proximal port of the catheter. All other ports and helical 
channels are occluded. When the injection has been completed, the cap can 
be cleaned and snapped back into place, to close off the port 72 in 
sterile fashion. 
The valve plug can then be returned to its normal (FIG. 22) position for 
this medical system, which is the position in which the indicator mark 81 
of the valve plug is aligned with the ARTERIAL indicator mark 84 on the 
housing. 
With this same medical system, when it is desired to draw a mixed venous 
sample from the distal port of the thermodilution catheter, the valve plug 
is rotated until the indicator mark 81 is aligned with the MIXED VENOUS 
mark 87 (FIGS. 21 and 30). 
Referring now to FIG. 30, in this orientation of the valve, the distal port 
of the catheter is connected to the port 12', which establishes 
communication through the port 70 in the cylindrical face of the valve 
plug with the axially-extending passageway 75 and the port 73 in the outer 
face 34' of the plug. To take a sample of blood, the closure cap flap 45' 
is lifted to remove the closure plug 48' from the port 73, and using a 
syringe, blood from the distal port of the thermodilution catheter can be 
aspirated from the port 73. 
To clear blood from the valve, the valve plug is rotated to align the 
indicator mark 81 on the valve plug with the MIXED VENOUS FLUSH indicator 
mark 83. Then, as shown in FIG. 31, communication is established from the 
port 73 through the axially-extending passageway 75, and through the port 
70, with the helical groove 66 which in turn communicates through the 
housing port 55 with the pressure transducer. Flushing originates at the 
transducer, with the flush liquid traveling through the communicating 
ports and passageways just mentioned. When the flushing has been 
completed, the closure cap flap 45' is cleaned and snapped back in place, 
and the valve plug may be returned to its normal position. 
Advantages of This Embodiment of the Invention 
Generally this embodiment of the invention affords all of the advantages 
already mentioned for the two channel, six port valve embodiment. However, 
in addition, the three channel, eight port embodiment is much more 
flexible, so that the valve can be used in several different modes. That 
is, it can be used in a medical system including a thermodilution catheter 
with an arterial line; with a thermodilution catheter alone; or with an 
arterial line in conjunction with a central venous pressure line, all 
without compromise of the valve function. 
In this embodiment of the invention, the offset of the housing port 55 from 
the opposite port 54 on the other side of the housing has a definite 
advantage. The port 55 is normally placed in communication with the 
pressure transducer. The port 54 is normally used for communication with 
the arterial line. The offset prevents high pressure bleed-back into one 
of the low pressure input ports. 
Still another advantage is that one pressure transducer can be employed for 
all desired pressure measurements. Simple manual rotation of the plug is 
the only requirement for switching the transducer among channels. 
Concluding Remarks 
Two preferred embodiments of the invention have been described in some 
detail above. The functions that are performed are of particular 
importance, whereas the specific structure illustrated in the drawings, 
while preferred, need not necessarily be used to perform the functions. 
For example, in both embodiments of the invention, the valve plug has been 
shown as having a generally cylindrical surface, as has the bore of the 
housing. Other mating surfaces of revolution would perform the same 
functions. Conical sections, for example, could be used for the mating 
surfaces of the rotary plug and of the bore of the housing. 
In describing the cooperating pairs of ports in the housing, it has been 
mentioned that they are preferably axially spaced relative to the bore of 
the housing. However, by appropriate modifications in construction, 
angular spacing could be employed, with the center lines of all ports 
falling in the same plane, while still accomplishing the desired 
functions. Some modification in the plug construction would of course be 
required. In addition, the spacing between the pairs of ports may be a 
combination of angular and axial. Those constructions illustrated are 
those that are preferred and generally those that are the simplest. 
Similarly, while diametrically opposed ports, and diametrically extending 
passageways for communication between ports, are preferred, such an 
arrangement is not essential. 
The valve plug preferably is constructed from a resilient plastic material, 
as a single part. Polypropylene produces a very strong hinge for the 
closure cap, although a long life is not essential since in most cases the 
valve would be constructed to be expendible. In any case, it is preferred 
for medical applications that the valve plug be opaque, whereas the 
housing should be transparent, to facilitate inspection for the presence 
of air bubbles, and to permit visual inspection of fluid flow. The valve 
can thus be made from only two molded parts, which preferably are 
sterilizable. However, the valve is intended for general utility and is 
especially useful wherever a cross-over between two parallel fluid flow 
lines is necessary. 
While the invention has been disclosed herein by reference to the details 
of preferred embodiments thereof, it is to be understood that such 
disclosure is intended in an illustrative, rather than in a limiting 
sense, and it is contemplated that various modifications in the 
construction and arrangement of the parts will readily occur to those 
skilled in the art, within the spirit of the invention and the scope of 
the appended claims.