US 3435819 A
Description (OCR text may contain errors)
April 1, 1969 G. s. REYNOLDS ETAL 3,435,819
VENOUS PRESSURE MONITORING APPARATUS Filed May 17, 1966 INVENTORS Gaza 01v 6: 57/1/04 05 [/42L 4 Pia/WW5? Je.
BY 2 W Q r Z- a ATTORNEYS United States Patent 3 435 819 VENOUS PRESSURE MofuToRING APPARATUS Gordon S. Reynolds and Karl A. Pannier, In, Salt Lake City, Utah, assignors to Le Voys Inc., a corporation of Utah Filed May 17, 1966, Ser. No. 550,732 Int. Cl. A61b /02; A61m 5/14 U.S. Cl. 128-205 Claims This invention or discovery relates to venous pressure monitoring apparatus, and more particularly to a simple and positive form of apparatus for measuring and indicating the blood pressure in the venous system, and while the apparatus will readily monitor peripheral venous pressure, the invention is highly desirable for use in accurately monitoring central venous pressure, although the invention may have other uses and purposes as will be apparent to one skilled in the art.
It has been learned that central venous pressure, pressure measured within the chest of a patient in a vicinity adjacent the heart itself, as distinguished from pressure measured in peripheral veins of the body, is least subject to extraneous influence, and therefore is the more reliable, indicative, and meaningful to the attending surgeon. Central venous pressure best provides information as to the condition of the heart and how well it is performing its function, what the circulating blood volume may be at any given time, vascular tone, and other information important to the attending surgeons and physicians. Such information indicates to the attending surgeon at any time desired whether a patient undergoing surgery should be immediately given a plasma extender, an electrolyte to improve vascular tone, additional blood, digitalis, or some other medicament or beneficial remedy. It is believed that numerous lives have been lost on the operating table because of lack of such information when needed. Therefore, the present trend is for physicians and surgeons to insist upon central venous pressure informa tion at any desired time, pre-operative, operative, and post-operative, at least in connection with major surgery cases.
Heretofore the most popular method of monitoring venous pressure was with the use of an open-topped manometer with which a rather confusing three-way valve was utilized, and also a bottle of infusion liquid, and suitable tubing for interconnecting the bottle and manometer, the manometer and a vein in a patient, and the infusion bottle with the patients vein, such different connections being controlled by manipulation of the valve or stopcock. In operating this form of device, the manometer had to first be filled with infusion fluid from the bottle, and then the valve could be turned to cut olf flow of infusion fluid and connect the manometer directly with the patients vein, whereupon the fluid level in the manometer would drop to a point indicating venous pressure. Then the manometer would have to be again filled from the bottle, and during that process infusion into the patients vein could not take place. In addition to the time lost refilling the manometer, this arrangement was objectionable in other ways mainly to the special arrangement of various sterile pieces required that was an objectionably burdensome task to assemble, and also the manometer frequently runs over in the process of filling it from the bottle, thus providing a most undesirable mess, and there is danger of error in manipulating the three-way valve.
Wtih the foregoing in mind, it is an important object of the instant invention to provide venous pressure monitoring apparatus embodying a manometer which cannot overflow, and in which apparatus a three-way stopcock or valve is not needed.
Patented Apr. 1, 1969 Also an object of this invention is the provision of venous pressure monitoring apparatus including a manometer, and in which a reading of venous pressure may be taken almost instantaneously at any desired time, and intravenous infusion may proceed immediately after such reading without waiting for the manometer to fill with infusion fluid.
Another object of this invention is the provision of venous pressure monitoring apparatus including a manometer so arranged that the manometer will fill with infusion liquid during intravenous infusion in a patient.
Also an object of the invention is the provision of venous pressure monitoring apparatus embodying a manometer that will automatically close at the top thereof when filled with infusion fluid, thus eliminating the possibility of the manometer running over.
It is still another desideratum of this invention to provide venous pressure monitoring apparatus that is economical, simple, practically foolproof, and which may be quickly and easily assembled in position for use.
While some of the more salient features, characteristics and advantages of the instant invention have been above pointed out, others will become apparent from the following disclosures, taken in conjunction with the accompanying drawing, in which:
FIGURE 1 is a fragmentary side elevational view of venous pressure monitoring apparatus embodying principles of the instant invention, showing the same in operative position for use with a patient;
FIGURE 2 is a greatly enlarged fragmentary central vertical sectional view through the manometer of FIG- URE 1, with parts shown in elevation; and
FIGURE 3 is a greatly enlarged fragmentary part sectional part elevational view showing the connection of the manometer needle with the tube leading therefrom.
As shown on the drawings:
The instant invention is used in combination with substantially any desired form of intravenous infusion sys tem including a system capable of infusing a patient from a single bottle or source of supply, or an infusion system capable of administering any of a plurality of infusion fluids or solutions from a plurality of sources of supply. By way of example, therefore, we have illustrated an infusion system including a conventional form of stand 1 from which two separate bottles or containers 2 and 3 are suspended. Connected to the underside of each of the bottles 2 and 3 is a conventional fluid metering device, these being designated 4 and 5 respectively. The bottle 2 discharges through an elongated flexible plastic tube 6 on which is a known form of clamp 7 which will pinch off flow through the tube or permit the tube to expand by its own resiliency and flow continue therethrough, simply by a flick of the attendants thumb in the proper direction. Similarly, the bottle 3 discharges through a tube 8, flow being controlled by a clamp 9. The tubes 6 and 8 lead to separate arms of a Y-fitting 10, the leg of which discharges into a tube 11 connected to a catheter 12 by means of a suitable Luer fitting 13 or the equivalent.
The catheter 12 passes through a vein in the arm of a patient diagrammatically indicated at 14, and extends to a point approximately at 15 in the superior vena cava in the vicinity of the patients heart 16. From this point, an accurate reading of the most reliable venous pressure taken from inside the chest of the patient is easily available. The catheter, which is approximately 24 inches in length, may be safely and expeditiously positioned so as to terminate in the superior vena cava by the catheter placement unit shown in FIGURES 1 to 6 of the drawings and described and claimed in W. H. Ring Us. Letters Patent No. 3,185,152 issued May 25, 1965.
The means for monitoring the central venous pressure of the patient 14 include a manometer 17 in the form of an elongated transparent tube of plastic, glass, or other suitable material. The tube carries a scale 18 along the length thereof, graduations being satisfactory in millimeters and centimeters, although other graduation measurements may be utilized, if desired. The manometer 17 is positioned with its longitudinal axis vertical and clamped as indicated at 19 to the upright of the stand 1 at a position well below the bottles 2 and 3. As seen in FIGURE 1, a manometer is preferably so positioned that the zero mark 20 on the scale 18 is at approximately the same level as the right atrium of the patients heart, as indicated by the dotted line 21.
At the open bottom end of the tube or manometer 17 there is a passaged fitting 22 to which a flexible tube 23 is connected, the opposite end of the tube 23 carrying a Luer-type fitting 24 for frictional engagement in a complementally shaped hub 25 carrying a needle cannula 26, as best seen in FIGURE 3. Near the upper end of the manometer tube a hollow seat 27 is cemented,
fused or equivalently secured to the inside tube wall to prevent a floating valve 28 disposed thereabove from dropping any further than the seat 27. The valve 23 comprises merely a tube of light weight plastic material having its lower end 29 bevelled or rounded and roughened or grooved in any manner suificient to permit the passage of air in both directions between the valve and the seat 27. The upper end of the valve is closed by way of a membrane 30 which may satisfactorily be a thin flexible plastic film, a rubber membrane, or any other suitable material inert to infusion fluid. At the top of the manometer tube there is a fitting 31 having an air port 32 therethrough and the fitting is provided with a depending rounded valve seat 33 immediately around the port. A tube 34 is connected to the open upper end of the fitting 31, and carries on its outer end a reservoir or receptacle 35 containing a mass of suitable filtering material 36 to prevent contaminants from being carried into the manometer tube by incoming air.
In use, the instant invention is extremely simple, accurate, and eflicient. The patient is prepared for surgery in the customary manner, and the catheter 12 is properly positioned within the patients body, as above explained, and connected to the infusion system. Infusion may then be started from either or both of the bottles 2 and 3, as the patients condition may indicate. Then the manometer needle 26 is entered into the infusion tube 11, as indicated in FIGURE 1, and the manometer immediately fills with infusion liquid, since the manometer is disposed well below the infusion bottles. The manometer tube 17 will fill almost to the top, and there will be a bubble of air trapped inside the valve 28 beneath the membrane 30, and the valve is floated up so that the membrane is pressed over the valve seat 33 closing the air port and preventing any of the infusion liquid running over from the manometer tube. The manometer is of a size such that it contains a higher column of liquid than venous pressure will support.
When it is desired to take a reading of the venous pressure, it is a simple expedient to clamp off infusion liquid flow with either of the clamps 7 or 9, depending upon which may be open. Immediately upon cessation of infusion, the liquid in the manometer will drop to the level to which it is sustained by venous pressure, the valve 28 admitting air into the manometer tube above the liquid level. The accurate venous pressure is then registered in the manometer, and as soon as it has been properly noted by the surgeon, infusion into the patient is again started, and the manometer immediately filled to the point where the valve is closed. Readings of the venous pressure may be taken whenever desired in the same manner and these readings will at once denote to the surgeon any variation in venous pressure so that the patient may be attended accordingly. Once infusion is stopped, the liquid in the manometer rapidly falls to the indicating level, and once infusion is started the manometer rapidly fills while infusion into the patients body goes on. Consequently, no time is lost in filling the manometer before infusion into the patient can occur. Therefore, there is no danger of blood backed into the catheter, and possibly into the manometer needle 26, clotting and ruining the entire venipuncture arrangement. Between venous pressure readings .it is not necessary to remove the manometer needle 26 from the infusion tube 11 but it may remain in position as long as desired and does not interfere in any manner with infusion into the patients body. It will also be noted that in most cases the manometer need not be thoroughly sterilized after each usage because blood from the patients body will only very rarely back into the manometer tube. It will also be noted that there is no danger of air being forced intravenously into the patient, since the only air flowing enters and leaves the upper portion of the manometer tube and none of that air can ever reach the infusion tubing.
From the foregoing, it is apparent that the instant invention is virtually foolproof, and any possible error in manipulation of a three-way stopcock in emergency circumstances is totally eliminated. There is no danger of the manometer running over at any time, and no time lost in filling the manometer between readings. Venous pres sure readings are available almost instantaneously at any time desired before, during, and after the surgery.
It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.
We claim as our invention:
1. Venous pressure monitoring apparatus including a manometer in the form of a transparent open-ended tube for disposition in a substantially vertical position,
a graduated scale on said tube,
means for placing the lower end of said manometer in communication with an intravenous infusion system,
a ported fitting on the upper end of said manometer,
automatically operable valve means to close the port in said fitting when the manometer is filled with infusion liquid to a predetermined extent.
2. The monitoring apparatus of claim 1, wherein said valve means is a float valve.
3. The monitoring apparatus of claim 2, wherein the valve comprises a tube of less diameter than said manometer, and
a membrane over the upper end of said valve tube, whereby a bubble of air may be trapped in said valve tube when the liquid level in the manometer reaches the valve.
4. The monitoring apparatus of claim 3, including a valve seat for abutment by said diaphragm around the port on the inner end of said ported fitting.
5. The monitoring apparatus of claim 2, including stop means in said manometer limiting the downward movement of said loat valve.
6. The monitoring apparatus of claim 1, wherein the means for placing the lower end of said manometer in communication with an intravenous infusion system include a passaged fitting on the lower end of the manometer,
a flexible tube connected at one end of said passaged fitting, and
a needle cannula removably connected to the other end of said flexible tube.
'7. In combination,
an infusion tube removably connected to said catheter,
a source of infusion fiuid in communication with said infusion tube,
means to control the flow of infusion fluid from said source,
an open-ended manometer tube disposed in substantially vertical position well below said source of infusion fluid, and
means establishing communication between the lower end of the manometer tube and said infusion tube, whereby said manometer tube will substantially fill with infusion fluid while infusion fluid flows to said catheter.
8. The combination of claim 7 including automatically operating valve means to close and open to air the upper end of said manometer tube in response to the rise and fall of the liquid level therein, whereby said manometer tube cannot overflow.
9. The combination of claim 7, wherein the means establishing communication between the manometer tube and the infusion tube include a tube connected at one end to the lower end of the manometer tube, and
a needle cannula removably connected to the other end of the last said tube.
References Cited UNITED STATES PATENTS 3/ 1909 Bishop 128-205 11/ 1931 Egster 1282.05 3/1964 Marbach 128-214 RICHARD A. GAUDET, Primary Examiner.
S. BRODER, Assistant Examiner.
US. Cl. X.R.