Medical fluid drainage and sampling system

Abstract

An improvement in medical fluid drainage systems, for permitting invasion of the system for sampling of the most recently collected fluid while insuring against the entry of infectious agents. A sample chamber is placed in a collection tube line between a catheter and a drainage collection vessel. The chamber has a self-sealing, elastomeric seal for entry of a sterile hypodermic needle to allow sampling of fluids collected in the chamber without contaminating the liquid in the chamber or the body of a patient to whom the system is connected.

Description

BACKGROUND OF THE INVENTION

Body fluid drainage systems such as urinary catheterization systems are well-known for medical use. In such systems a Foley-type catheter is inserted into the bladder in the body of a patient and often connected through flexible tubing to a collection vessel. The catheter is maintained in the body for long periods of time often for days or even weeks. Samplings are taken from the collection vessel periodically to perform desired urinalysis studies. It has long been a problem that patients are susceptible to infection traveling through the catheterization system up into the body. Bacteria can invade the system as when samples are taken from the collection vessel.

There have been a number of systems suggested to prevent bacterial infection to the patient during urinary catheterization over long time periods. However, most commonly used medical procedures and systems still result in an undesirably high rate of infection to patients.

SUMMARY OF THE INVENTION

It is a primary object of this invention to provide an improvement in medical fluid drainage systems for permitting invasion of the system for sampling of the most recently collected fluid while insuring against the entry of infectious agents.

Still another object of this invention is to provide an improvement in accordance with the preceding object which is inexpensive and can readily be adopted to existing systems rapidly and efficiently.

Still another object of this invention is to provide an improvement in accordance with the preceding objects which can be used by relatively untrained medical personnel without the need for physician supervision.

Still another object of this invention is to provide an improved means for permitting invasion of a medical fluid drainage system and sampling of the most recently collected fluid while insuring against entry of infectious agents to the system and thereby lowering the danger of infection to the patient.

According to the invention, a sample chamber is provided in a medical fluid drainage system for conducting fluid from the body of the patient which system has a fluid collection vessel and a fluid collection tube connected to a catheter in the patient's body. The sample chamber comprises a self-sealing elastomeric seal in its wall which seal permits entrance of a sterile hypodermic needle while the remainder of the system is maintained sterile to withdraw fluid samples for testing. Preferably the sample chamber has means for preventing backflow of fluid from the chamber to the body and means for holding a predetermined volume of body fluid while allowing passage to the collection vessel of additional body fluid passing from the body.

It is a feature of this invention that the sample chamber enables sampling of the most recently collected fluid specimen since the chamber can be placed close to the catheter leading from the body. Because sterile invasion of the system for sampling can be carried out, samples can be taken more frequently than is the case with existing surgical drainage systems where each opening of a collection device can lead to bacterial infection. This is particularly useful in tests such as the Schilling test where radioisotopes are injected into the body and the urine collected for 24-hour periods. Often the urine is tested and the collection vessel emptied only at the end of a 24 hour period to determine the degree of absorption. With the system of this invention, it is possible to sample every two or four hours or as desired without leading to bacterial infection yet obtaining a rate of isotope absorption as well as a total amount in any 24 hour period.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features, objects and advantages of the present invention will be better understood from the following specification when read in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of a medical fluid drainage system of this invention;

FIG. 2 is a side view of an element thereof;

FIG. 2a is a cross sectional view through line 2a--2a of FIG. 2;

FIG. 3 is a side view of an alternate embodiment of an element thereof;

FIG. 4 is a side view of another alternate embodiment of a sample chamber; and

FIG. 5 is a view through line 5--5 of FIG. 4.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference now to the drawings and more particularly FIGS. 1 and 2, the urinary catheterization system 10 is shown having a preferred embodiment of a sample chamber 11 of this invention incorporated therein.

The conventional parts of the system 10 as normally used in urinary catheterization include a Foley or other drainage catheter 12 which is inserted in a body of a patient diagrammatically indicated at 13 and has an end 15 attached to a plastic or rubber collection tube 14 forming an input portion and a lower output tube portion 16. The output portion of the tube is attached to a conventional metering vessel or chamber 17 which is in turn linked by a drainage tube 18 to a storage vessel or chamber 19.

In conventional practice, the plastic tube portions 14 and 16 are a unitary collection tube leading directly to the metering chamber. The metering chamber may be for example, a Curity urine-meter produced by Kendall Corporation of New Jersey, having rigid transparent plastic walls with calibrated volume markings to determine the volume of fluid output from the patient. Preferably the metering chamber has a drainage stopper 20 to allow sampling as in conventional practice although it is preferred that this drainage stopper not be used. The storage chamber 19 is preferably a Curity bedside drainage bag produced by Kendall Corporation of New Jersey formed of thin plastic walls and having a collection tube 21 stoppered as at 22 by a clamp with a microporous filter 23 allowing equalizing of air pressure when fluid enters the system but preventing bacterial invasion of the system. Thus the system is closed to the atmosphere except at filter 23.

In accordance with this invention, the sample chamber 11 is provided. The sample chamber 11 is preferably of a rigid plastic such as polystyrene in the form of two joined conical portions 30 and 31 each having tubular stems 32 and 33 extending through the apex ends. The stems extend into the space within the chamber. Thus, fluid collected in the chamber does not pass down the tube 16 until a level is reached above the level of the orifice 34 of the stem 32. This permits a fresh sample to always be present within the chamber 11 while permitting over-flow to pass through the collection tube 16 to a collection vessel. Similarly, the extension of the stem 33 to an area within the chamber spaced from the side walls of the chamber, prevents backflow of liquid to the patient. When the chamber is inverted, since the stem 33 extends at least as far into the chamber as the stem 32, no backflow is possible to the patient.

The chamber 11 also carries an orifice 35 in which is mounted an elastomeric self-sealing seal 36. This seal can be a rubber plug as for example the type used in resealable pharmaceutical vials and Vacutainers (a trademarked product of Becton, Dickinson & Company of Columbus, Nebraska and Rutherford, New Jersey) and the like. Thus, fluid specimens within the chamber can be sampled by inserting a hypodermic needle through the plug 36 withdrawing a sample of the fluid and then removing the hypodermic needle whereupon the plug automatically reseals the chamber. Since all parts of the system are sterilized initially before use, if a sterile hypodermic needle is used, invasion of the system by the hypodermic needles does not cause bacterial entrance into the system. Thus, sterile invasion of the system is possible with sampling at whatever time intervals desired. It is preferred that the chamber 11 be as close to the catheter 12 as possible in order to enable collection and sampling of the freshest fluids removed from the body at all times.

In using the system 10, the Foley catheter is connected to the patient and the apparatus set up as shown in FIG. 1. As fluid drains from the patient, it is passed to the sample chamber 11 which is preferably located below the level of the patient and preferably in a generally upright position. However, the system can be near horizontal although the orifice 34 should always be somewhat below the orifice of the stem 33 to allow drainage to the collection vessel rather than passage back to the patient. Fluids collect below the level of rim 34 and overflow passes to the metering chamber 17 where volume can be measured at periodic intervals. At such intervals, the storage chamber 19 can be lowered with respect to the metering chamber to cause drainage of the metering chamber into the storage chamber. Thus, large volumes of fluids can be stored without the need for opening the system to the atmosphere over short time periods. This prevents bacterial invasion of the sterile system which could be caused by bacteria carried in the atmosphere. At any time during drainage, a sterile hypodermic needle can be inserted through the plug 36 to sample fresh fluid collected below the level of rim 34. Preferably the chamber 11 is transparent to allow visual access to the chamber which is preferred. The chamber can be completely drained by the sampling needle if desired.

Turning now to an alternate embodiment of a sample chamber 11, a plastic thin wall rigid sampling chamber 40 is illustrated in FIG. 3 having a stem 32 as previously described with conical sections 30 and 31. A plug 36 as previously described is mounted in the conical section 31. In this embodiment, the stem 33 is truncated at the entrance to the chamber and a divider wall 41 extends across the chamber having a central aperture 42. In this embodiment, fluid collected passes through the aperture 42 when the chamber is vertically held. Thus, the first portion of the chamber provides one collection area when the chamber is other than vertical while allowing drainage to the second chamber when the chamber is vertically held. Sampling can be accomplished by inserting a needle through plug 36 to either the first or second portion of the chamber. If desired, additional plugs 36 can be used in the lower portion of the chamber.

FIGS. 4 and 5 illustrate still another embodiment of a sample chamber in accordance with this invention. As in the first alternate embodiment, identical numbers indicate identical parts to those shown in FIGS. 1 and 2. The sample chamber 50 has walls 30 and 31 with inwardly extending stem 32. In place of the stem 33, a one-way valve 51 is positioned in the end of tube 15 to prevent backflow to the patient. The valve is formed of a resilient nipple having a slit 52 which allows flow to chamber 50 but prevents backflow to the body of the patient. In this embodiment, stem 52 ends at the chamber wall 31.

While specific embodiments of the present invention have been shown and described, many modifications are possible. The chamber 11 or modifications thereof need not be made of plastic. Glass, or other materials can be used. Although it is preferred that the sample chambers be transparent, in some cases, opaque walls can be used. Similarly, the size and number of self-sealing seals used can vary.

The specific collection and metering chambers can be any of those known in the art. While it is preferred that the system be closed to the atmosphere, the sampling chamber has use even in open systems to collect the freshest sample removed from the patient.

It is preferred that the volume of the chamber 11 hold from 1 to 100 cc, and preferably 10 cc in urinary catheterization, before additional fluids are passed to the collection or metering chamber. Thus, normal urinary output of 1000 to 2000 cc per 24 hour period passes to the metering chamber always leaving a sample which is a fresh sample of a predetermined size in the sample chamber. For example, when the total volume of the sample chamber is 200 cc, approximately 10 cc is preferably left for sampling at all times by proper dimensioning of the length of stem 32. If desired, volumetric calibrations can be mounted directly on the wall of the sample chamber to determine the volume held in the chamber.

The specific size and configuration of the sample chamber 11 can vary greatly as desired. While conical-shaped portions are shown in the preferred embodiment, the chamber can be circular or of irregular configuration. While rigid walls are preferred, in some cases, resilient or collapsible wall devices can be used although it is preferred that the stem 32 always have its orifice 34 spaced from the walls of the chamber.

While the stem extending into the chamber provides for collection of a portion of fluid desired, in some cases, valves of various types can be used in place of the inward extension of the stem 32. Valves or other means can be used to provide for filling of the chamber to a desired level with a preselected amount of fluid drained, after which, excess fluid drains to the storage vessel. In all cases, it is important that a self-sealing, seal be mounted on the chamber in operative relationship to the fluid portion collected for sampling, to allow sterile invasion of the system for sampling purposes.

While urinary catheterization has been specifically described, the method and apparatus of this invention can be used in connection with other medical drainage systems. For example, use can be made in nasal and gastric drainage.

The hypodermic needle used for sampling is preferably attached to a sterile vacuum tube. However, sterile syringes and the like can be used so long as the system is maintained free of the entrance of bacteria during sampling.

Claims

What is claimed is:

1. In a medical fluid drainage system for conducting fluid from the body of a patient, said drainage system comprising a fluid collection vessel and a fluid collection tube, the tube being connected at one end to a catheter insertable in the patient and to the vessel at another end, the improvement comprising, a wall defining a closed unitary sample chamber mounted intermediately in said collection tube between the catheter and the collection vessel, establishing an input section of the tube between the catheter and the sample chamber, the input section being connected to a first opening in the wall and the sample chamber also establishing an output section of the tube between the collection vessel and the sample chamber, the output section being connected to an output tubular stem means extending through a second opening in the wall for collecting a sample in the chamber and terminating inside said chamber and spaced from said wall at its termination within the chamber,

an elastomeric self-sealing seal means in the wall of said chamber constructed and located to receive a sterile hypodermic needle therethrough into communication with a collected sample and to maintain its seal upon withdrawal of such hypodermic needle whereby collection of the most recently drained fluid from a patient's body is permitted by sterile invasion of the system.

2. The improvement of claim 1 and further comprising means for preventing backflow of fluid from the sample chamber to the input section of the tube.

3. The improvement of claim 1 wherein said sample chamber further comprises an input tubular stem extending into said chamber and spaced from said chamber wall at an orifice end.