MXPA00002874A - Closed, one-handed blood sampling system - Google Patents

Abstract

A one-handed blood sampling reservoir (80) for an infusion line (74, 82) having a configuration which allows fluid to be drawn into the reservoir and then returned to the patient. Both drawing and returning steps are performed by squeezing two of a plurality of finger grips (180, 274, 126, 180) provided on the reservoir (80). The reservoir may include a bracket (87) which enables one-handed operation in either a hand-held or a pole-mounted configuration. In the alternative, the reservoir and finger grips may be formed by telescoped inner (322) and outer housings (306) without a bracket. The reservoir desirably includes a syringe-like body forming a chamber (102) and a plunger/piston assembly (104) reciprocal therein to vary the volume of the chamber. A narrow gap (G) is provided in the chamber open to both inlet and outlet ports when the piston is fully seated to ensure a consistent and minimum flush volume in the chamber. The reservoir is preferably placed within an infusion line having a pressure transducer (90) therein, and a spring-loaded piston (110, 114) may be adjustable to vary the dynamic response of the fluid pressure system.

Description

BLOOD SAMPLING SYSTEM. IN ONE HAND CLOSED FIELD OF THE INVENTION The present invention relates to blood sampling systems and, in particular, to one-hand blood sampling systems, closed and methods of use.

BACKGROUND OF THE INVENTION In a hospital facility there is always a need to monitor the health of patients by evaluating the profile of blood chemistry. The simplest method used in the hospital is to use a syringe that has a sharp cannula at one end and insert the cannula into a vein or artery to draw a sample of blood from the patient. Patients who are in critical care units or operating rooms sometimes require up to twelve samples per day. Such injection sampling is frequent, potentially exposing the patient to bacteria and viruses from the environment which can enter the bloodstream through the opening made by a sharp cannula. In addition, accidental stings often occur with the needle for the nurse or technician. He REF, 33051 problem of infection by accidental needling or needle damage to contract viruses such as HIV or hepatitis has prompted the medical field to adopt alternative blood sampling systems. One way to obtain a blood sample is to draw blood from a catheter that has been inserted in advance into the patient, either in a central venous line, such as one placed in the right atrium or in the arterial line. Typically, there are injection sites for infusion of arterial or venous medications or pressure monitoring lines that are used to take periodic samples of the patient's blood. Conventional mechanisms for drawing blood from the lines used for infusion or pressure monitoring use a plurality of stopcock mechanisms that impede flow from the infusion fluid supply or from the drip supply of the pressure column, although they allow blood flowing from the patient to a collection syringe connected to a removal hole formed in one of the stopcocks. However, the closing keys increase the contamination and the risk of infection, and increase the waste of blood. In addition, the first uses of sampling site were made with sharp cannulas forced through an elastomeric septum that is provided in a hole in the housing of the stopcock. Repeated perforation of the septum at such injection sites was a source of physical damage known as microegregation or laceration which can shorten the effective duration of the injection site. In addition, such an apparatus does not eliminate the danger of a nurse or doctor being cut with a sharp cannula. The next development of the sampling systems was to use a blunt cannula and sliding septa. Although the blunt cannula eliminates the danger of sting to the nurse or physician, the possibility of infection of the bloodborne pathogens remains since the blood at the sampling site and the syringe are typically under arterial or venous pressure, and in extreme cases it may cause a fine blood sprinkling which makes contact with the user. The first systems also require the operation of two stages where a first fluid sample, generally about 5 ml in volume for intensive care environments, is drawn into the sampling syringe and discarded. The first sample potentially includes part of the infusion fluid and thus could an unreliable blood chemistry measurement sample. After the initial sample has been discarded, the second sample is pure blood from the artery or vein. In addition to the unnecessary loss of blood, the two-sample process potentially introduces potential effects in relation to problems such as air production in the air piping and introduction of contaminants into the blood supply. The two-stage process also requires a substantial effort on the part of the nurses or other physicians who must draw the blood sample. In response to the drawbacks associated with the first sampling systems, closed systems such as the blood sampling device have been developed in U.S. Patent No. 4,673,386 to Gordon. The Gardon device is shown schematically in Figure 1 and comprises a piston / chamber device 20 positioned in an infusion line upstream of a sample orifice 22. Sampling orifice 22 includes a slidable septum 24 into which a blunt cannula 26 may be inserted for sampling blood therefrom. When used, the piston in the device 20 is retracted to draw fluid from the patient into the fluid supply and store it in the chamber. Sufficient fluid is drawn into the chamber to take a supply of pure blood past the sampling orifice 22 so that the syringe 28 can draw a usable sample of blood through the blunt cannula 26. In some systems which make use of the Gordon device, such as the Edwards Critical-Care Venous Arterial Blood Management Protection System (VAMPMR), a total shut-off valve is placed between the piston / chamber device 20 and the orifice 22 of the device. Sampling to ensure that syringe 28 does not draw any of the diluted blood or infusion solution from inside the chamber. Such closed systems eliminate the problem of needle bites, and reduce the number of injections in the patient to one, for the initial introduction of the cannula. The process still requires two-hand operation of the piston / chamber device 20, followed by the two-handed operation of the syringe 28 to obtain the blood sample. As mentioned before, blood samples can also be taken from catheter tubes used for blood pressure monitoring. The Gordon closed system shows a pressure transducer 30 positioned in the pressure line connected to a monitor 32 which shows the blood pressure. Such pressure lines typically make use of a relatively rigid tubing primed with a suitable IV fluid such as saline or 5% dextrose solution as a pressure column. For adults, a bag pressurized with air surrounds the IV fluid supply bag to maintain a constant pressure differential in the tubing that constantly pushes fluid to the patient through the restrictor orifice. Slow drip of IV fluid discharges the tubing to prevent coagulation. The transducer includes a diaphragm exposed to the pressure column on one side and has a device for measuring the reflection of the diaphragm on the other. Some transducers such as the TruWave ™ disposable pressure transducer available from Baxter Healthcare of Irvine California include a discharge device that can also be used to send pressure waves to the patient through the tubing. A Snap-Tab ™ TruMR ™ device is a rubber tab which, when pulled and then released, sends a square wave through the pressure column which can be used to verify the inherent frequency response of the whole system, which includes the pipe and any components attached thereto, such as sampling holes and temporary fluid storage devices. The frequency response of the appropriate system is necessary for reliable measurements of blood pressure. Another closed sampling system manufactured by Abbot Laboratories and described in U.S. Patent No. 5,324,266 for Ambrísco et al., Is shown in Figures 2A and 2B. This system includes a supply 34 of fluid connected through conduit 36 to a variable flow control device and a discharge valve 3B. The discharge valve is connected to the proximal end of a fluid storage mechanism 40 having a piston 42 therein with a hollow interior 44. The infusion fluid from the supply 34 drips through the hollow interior 44 and through a swirl inducing element 48 out of the storage mechanism 40. The infusion fluid continues through line 36 past full shut-off valve 50, a sampling orifice 52 and finally through a sharp cannula 54 which has previously been implanted in the patient. When a blood sample is required, the user holds the locking cap 56 and presses both sides, releasing it from a flange 58. As the lid 56 is removed, the piston 42 generates a vacuum within the blood storage mechanism 40 by pulling blood and residual infusion fluid from the patient into the chamber 60 (Figure 2B). At this point, the total closure valve 50 is closed, and the blunt-tipped cannula is used to draw a sample of blood from a sampling orifice 52. Although the device in the Ambrisco patent is supposedly easier to use than the Gordon device due to its concentric filling chamber configuration, a two-hand operation is still required to pull fluid into the chamber 60 and a two-way operation. hands to draw blood from hole 52 of. sampling. In view of the foregoing, there is a need for a simplified system and method for blood sampling.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a preferred fluid sampling system comprising a conduit pipe with a proximal portion adapted to be supplied with a fluid, and a distal portion adapted to be in communication with a fluid system of a patient. A reservoir assembly having a variable volume chamber includes an inlet opening open to the proximal portion of the conduit line and an outlet orifice open to the distal portion of the conduit line. A piston is movable inside the chamber to vary the volume of the chamber. The tank assembly has a first pair of pressure surface faces remote from each other and adapted to move the piston relative to the chamber to increase the volume within the chamber, and a second pair of pressure surfaces oriented away from each other and adapted to displace the piston with respect to the chamber to decrease the volume within the chamber, wherein the fluid can be withdrawn into the chamber and expelled therefrom by actuation of the first and second pair of pressing surfaces, respectively . The reservoir assembly may comprise a syringe-like device and includes a bracket for mounting the mount to an external bra the syringe-like device is attached to the mounting bracket, wherein one of the first pair of pressurized surfaces is on the bracket. The reservoir assembly can include a body defining the chamber within a plunger assembly comprising the piston at a first end, and a plunger at a second end extending out of the body, wherein the plunger defines the other of the first pair of pressed surfaces to cooperate with one on the support. Preferably, the plunger defines one of the second pair of pressurized surfaces, and the body includes a member that extends generally radially outward, which defines the other of the second pair of pressurized surfaces to cooperate with one of the plunger. The present invention also provides a preferred method of fluid sampling using a reservoir assembly and a sampling orifice that is located on a line attached to a catheter in communication with a fluid system of a patient. The method comprises pressing a first pair of depressed surfaces in the reservoir assembly, the first pair of depressed surfaces being oriented in opposite directions, so as to move a piston within a chamber of variable volume defined within the reservoir assembly and It extracts a fluid from the patient by passing the sampling orificic and inside the chamber. The fluid is sampled from the sampling port, and a second pair of pressing surfaces oriented in directions opposite the reservoir assembly are depressed to move a piston within the variable volume chamber and infuse fluid from the chamber past the sampling port. inside the patient. The reservoir assembly may include a syringe-like device having an axis in which the pressure of the first and second pair of pressurized surfaces moves the piston axially to increase or decrease the volume of the chamber respectively. The reservoir assembly can include the syringe-like device and a mounting bracket for mounting to an external support, wherein the syringe-like device is attached to a mounting bracket, wherein one of the first pair of depressed surfaces is the support. The mounting bracket may have a retaining portion and the syringe-like device may have a body defining a chamber therein, wherein the body is received in the retaining portion and is maintained preventing axial movement with respect thereto. . In a preferred form, a plunger assembly comprising a piston on a first end and a plunger on a second end extending out of the body is provided., wherein the plunger defines the other of the first pair of pressurized surfaces to cooperate with one on the mounting bracket. Additionally, the plunger may define one of the second pair of pressurized surfaces, and the body may include a member that extends generally radially outwardly, which defines the other of the second pair of pressurized surfaces to cooperate with one on the plunger. In another preferred embodiment, a reservoir is provided for use in a fluid sampling system. The deposit comprises: a deposit body that defines a chamber inside; a piston having a piston wall facing the chamber and movable within the body from a first position to a second position to vary the volume of the chamber; a fluid inlet port and a fluid outlet port open to the chamber; the structure of either the body or the piston which maintains a minina separation between the piston wall and the body when the piston is in the first position, the separation defines a volume in which the inlet and outlet holes are communicated to allow the fluid to flow between them; and a deflection element which urges the piston wall to the first position. The present invention also provides another preferred method for unloading a reservoir used in a sampling system. The method comprises the steps of providing a reservoir having a chamber and a displaceable piston having a piston wall facing the chamber and movable within the body to vary the volume of the chamber, connecting a proximal portion of the tubing between a discharge fluid source and an inlet to the variable volume chamber, connect a distal portion of the tubing between a patient's fluid system and an outlet to the variable volume chamber, divert the piston to a first position within the variable volume chamber with the piston wall adjacent to the inlet and outlet holes, and maintain a minimum separation between the piston wall and the chamber when the piston is in the first position with structure in the chamber or piston, the separation defines a volume in which the inlet and outlet holes communicate and allow the fluid to flow from the proximal portion of the pipe to the porc distal ion of the pipe. In another preferred embodiment, a reservoir is provided for use in a fluid sampling system. The reservoir comprises a reservoir body defining a variable volume chamber therein, the body having a peripheral wall and a bottom wall. A fluid inlet orifice extends perpendicularly through the lower wall of the body and opens to the chamber. A fluid outlet hole also opens towards the chamber. A piston is displaceable within the body from a first position adjacent to the lower wall, to a second separated position further away from the lower wall to increase the volume of the chamber. The piston has a pressure surface which is spaced apart from the bottom wall to form a narrow gap between them when the piston is in the first position, with the fluid inlet and outlet openings towards the separation. Finally, a seal surrounds the pressure surface and provides a fluid tight seal between the piston against the peripheral wall of the chamber. The fluid enters the chamber through the inlet port when the piston is in the first position and is directed generally in a 360 ° direction through the bottom wall and towards the peripheral wall of the chamber. The additional objects and advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description of a currently preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram of a blood sampling system of the prior art; Figures 2A and 2B are schematic cross-sectional views of another blood sampling system of the prior art; Figure 3 is a schematic diagram of a blood sampling system of the present invention incorporating an improved blood sampling reservoir; Figures 4 and 5 are front and rear perspective views of the blood sampling reservoir used in the system of Figure 3; Figure 6a is a side elevational view of the main body of the reservoir of Figures 4 and 5; Figures 6b and 6c are top and bottom plan views of the main body of the reservoir; Figure 7a is a cross-sectional view of the main body of the reservoir taken along line 1a-1a of Figure 6c; Figure 7b is a cross-sectional view of the main body of the reservoir, taken along the line 7b-7b of Figure 6c; Figures 8a and 8b are top and bottom perspective views of a piston assembly of the reservoir of Figures 4 and 5; Figures 9a and 9b are front elevation and side views of a piston component of the reservoir of Figures 4 and 5; Figure 9c is a top plan view of the plunger; Figure 9d is a cross-sectional view of the plunger along line 9d-9d of Figure 9a; Figures 10a and 10b are top and bottom perspective views of a lid component of the reservoir of Figures 4 and 5; FIGS. 11 and 11b are top and bottom perspective views of a piston component of the reservoir of FIGS. 4 and 5; Figures 12a and 12b are side and front cross-sectional views of the assembled reservoir of Figures 4 and 5 showing a plunger assembly fully housed within the main body; Figure 12c is an enlarged portion of the reservoir within circle 12c-12c of Figure 12b; Figure 12d is an enlarged portion of the reservoir within circle 12d-12d of Figure 12b; Figures 13a and 13b are side and front cross-sectional views of the assembled reservoir showing the plunger assembly fully retracted within the main body; Figure 14 is a schematic cross-sectional view of a sampling reservoir similar to that shown in Figures 4 and 5 with an adjustable piston spring load; Figure 15 is a perspective view of an alternative blood sampling reservoir of the present invention; and Figures 16a, 16b and 16c are "cross-sectional views of a blood sampling tank similar to that shown to that of Figure 15.

DESCRIPTION OF THE PREFERRED MODALITIES The present invention comprises a hand-held, fenced and improved blood sampling system, especially useful for the operating room or critical care unit (CCU). This system provides flexibility by allowing a blood collection tank to be mounted on a support or removed from the support, and the operation of the deposit requires minimal effort. In one form, the reservoir is part of a pressure monitoring system and includes a consistently open channel for flow therethrough to discharge surfaces in contact with the blood. An inlet and outlet to the tank additionally ensures good discharge of the channel therethrough. In another advantageous feature, the blood sampling system allows adjustment of the frequency response of the pressure column to provide clearer and more accurate readings of the pressure sampling transducer within the system. These and other advantages will be apparent from the following detailed description.

SAMPLING SYSTEM Figure 3 schematically illustrates a blood sampling system 70 of the present invention. The system 70 comprises a distal end 72 terminating in a male luer-type connector 76 for attaching to a female luer connector (not shown) of an injection site, or another conduit that is directed to the patient. A first intubation line 74 extends between the distal end 72 and a one way stop key 78. The closure key 78 is preferably rigidly attached to the lower end of the reservoir 80. A second intubation line 82 extends from the reservoir 80 in a proximal direction and terminates in a female luer connector 84 at a proximal end 86 of the sampling system 70 of blood. The reservoir 80 is removably mounted to a support 87, which in turn, can be fixed to a conventional pole holder with the reservoir in a vertical orientation. As mentioned above, the blood sampling system 70 preferably forms a portion of a pressure monitoring system, and a female luer connector 84 is attached to a T-union 88 which in turn has a hole connected to a transducer 90 pressure, such as a Tru aveMR disposable pressure transducer available from Baxter Healthcare of Irvine California. A supply of discharge solution (not shown) is connected to a discharge port 92 of the transducer 90. In addition, a supply of infusion fluid (not shown) can be provided in communication with an infusion port 94 of the junction 88 in T. The pressure transducer 90 is thus placed in fluid communication with the patient's arterial or venous system through the lines 74 and 82, and preferably includes a coaxial cable and a pin 96 for connection to an exhibit monitor. The sampling system 70 further comprises a pair of sampling sites 98a and 98b. Each of the sampling sites 98 desirably define Z-shaped passages therein to induce turbulence and improve clarification of blood from around a septum prior to a groove (unnumbered). With this configuration, a minimum amount of discharge volume is needed to clean the pipe before sampling. The septum preferably comprises a latex disc which accepts a blunt cannula and reseals after each sample is removed, which reduces the potential for contamination and eliminates the danger of pinching by needles. Such a sampling site is described in U.S. Patent No. 5,135,489 to Jepson, et al., Which is expressly incorporated herein by reference.

DEPOSIT Figures 4 and 5 illustrate one embodiment of a blood sampling tank 80 of the present invention attached to the support 87. The reservoir 80 is desirably a syringe-type variable volume chamber for withdrawing fluid from the distal end 72 of the system 70. In addition, reservoir 80 includes a constantly open flow channel for passage of discharge fluid from end 86 proximal to distal end 72. Finally, the tank 80 has the ability to re-infuse blood and other fluids extracted into the tank during the sampling operation, thereby eliminating a wasted volume. The complete sampling system 70 is thus closed because the "priming" volume ensures a pure sample of blood at the sites 98a and 98b which remains within the system 70 and is reinfused into the patient's interior. It will be understood by those skilled in the art that the modality 80 of the type of syringe shown in Figures 4 to 5 is exemplary only and that other configurations may be designed to adequately perform the functions of the invention of the present application. For example, the reservoir 300 shown in FIG. 15 is a further embodiment which does not include a detachable holder for one-handed operation. Briefly, the present preferred embodiment of Figures 4 to 5 should be considered as exemplary and not necessarily limiting.

ASSEMBLY OF THE PENCIL As seen in the cross section in Figures 7a and 7b, the reservoir 80 comprises an outer body 100 defining an internal cylindrical chamber 102 which receives a plunger assembly 104. With reference to Figures 8a and 8b, the plunger assembly 104 comprises, from the top to the bottom, a plunger 106, a lid 108 adapted to be attached to the open upper end of the chamber 102, a plunger 110 and a seal 112 The reservoir 80 is generally elongated along an axis which will be described for orientation purposes as vertical with the cap 108 on an upper end thereof. However, when used, the deposit 80 will often be inverted, as described later. The reservoir body 100, the plunger 106, the cap 108 and the piston 110 are preferably molded from biocompatible polycarbonate parts, while the seal 112 preferably is made of a silicone elastomer. However, other materials may be suitable.

The assembled plunger assembly 104 performs reciprocating movement vertically within the chamber 102 and the seal 112 is sized to provide a fluid-tight displaceable packing or sweep at the bottom of the plunger bottom 104. With reference to Figure 12a, the plunger assembly further includes a spring 114 placed in compression between the plunger 106 and the piston 110, and a contamination cover 116 surrounding a main plunger assembly portion 104. These components will be described in greater detail later.

DEPOSIT BODY As best seen in Figures 6 and 7, the exterior of the body 100 is preferably cylindrical and includes graduations 120 with corresponding numeric markings indicating a volume of fluid within the chamber 102. In this regard, the body.100 includes a wall Bottom flat and circular, and a top mouth 124 (which receives the lid 108). A pair of diametrically opposed slots 125 are formed near the upper part of the body 100 to secure the lid 108 over the mouth 124. A pair of outwardly extending gripping fingers or fins 126 are provided proximate the open mouth 124. Additionally, the body 100 includes a pair of outer tabs 127 positioned on both sides of each slot 125, to interact with the support 87. In one embodiment, the body 100 comprises a cylinder of constant diameter from the wall 122 lower than the mouth 124 that has an inner diameter of approximately 1.90 cm (0.75 inches) and a height of approximately 7.6 cm (3 inches). In this modality, the chamber 102 has a volume sufficient to extract at least 12 cc of fluid, which is typically sufficient for sampling procedures in the operating room. In other embodiments, the reservoir 80 can be provided only for applications in CCU and may include a smaller extraction volume. Below the lower wall 122 of the body 100 there are provided fluid inlet and outlet holes to the chamber 102 as best seen in Figures 6b and 7a. More particularly, when observing inside the upper part of the chamber 102 of Figure 6b, an inlet hole 130 is formed as an opening in the lower wall 122 in a position approximately halfway between the periphery and the center of the chamber. the camera. An outlet port 132 preferably of the same diameter is provided in the inlet hole 130 near the periphery of the chamber 102. As used herein, the term "inlet" refers to the direction of the fluid flowing from a source of solution discharge to the patient, but it will be understood by those skilled in the art that in the sampling operation, the fluid actually flows through the exit orifice 132. The exit orifice 132 opens an intubation lumen 134 defined within a rigid cylinder 136. Similarly, the inlet orifice 130 opens to the lumen 138 defined by a rigid cylinder 140. The cylinders 136 and 140 are downwardly dependent from the lower wall 122 approximately the same distance and are connected by a rib 142. The rib 142 reinforces the cylinders 136 and 140 to prevent accidental rupture thereof. The lumen 134 has a first diameter and opens to a larger lumen 144. Significantly, the lumen 138 leads to the inlet 130 and is oriented perpendicularly to the lower wall 122 to improve the discharge operation of the reservoir described below. The gradual lumens 134 and 144 receive a nipple of the key valve 78, seen in Figures 4 and 5. The key valve 78 typically comprises a cylindrical main body 150 defining a housing within which the valve rotates 152 of closing key. In the present embodiment, an arcuate shoe 154 is shaped to receive the main cylindrical body 150 of the key valve 78 and is rigidly attached to the lower end of the rib 142. Desirably, the stepless diameter of the key nipple The closure end is glued in place within the lumens 134 and 144. The end of the body 150 of the opposite valve of the nipple comprises a female connector tube 156 for receiving the first intubation line 74, as seen in FIG. 3. Similarly, the lumen 138 of tubing for the inlet 130 receives the second intubation tubing 82. The intubation lines 74 and 82 can be glued in place for safety. The lower wall 122 further includes one or more vertical projections or shoulders 158a, 158b and 158c extending inside the chamber 102 which interact with the piston 110 to separate it from the lower wall, as will be explained later, and ensure a volume of consistent and minimal discharge into the reservoir 80. Desirably there are at least three shoulders 158a, b, c evenly spaced around a circle positioned slightly off-center on the bottom wall 122 towards the exit orifice 13_2. The circle around which the shoulders 158a, b, c are placed are separated from the side walls of the chamber 102 to leave a non-obstructed peripheral band 159 surrounding the shoulders. A first shoulder 158a is preferably located adjacent and radially inward from the exit orifice 132, while the other two shoulders 158b, 158c are located approximately 120 ° around the circle from the first and on both sides of the inlet hole 130. This arrangement provides a tripod support for the piston 110 and minimizes clogging to the discharge fluid flow. Preferably, the shoulders have a rounded cross section, although other shapes can be substituted. In addition, and as will be evident below in the description of the operation of the deposit, a single ledge may be sufficient for separation purposes.

PLUNGER Figures 8a and 8b show plunger assembly 104 including plunger 106 which comprises, as seen in detail in Figures 9a-d, a relatively thin, elongated stem 160 terminating at an upper end on a plate 162 upper whose upper surface forms a support 164 for the thumb, and at the lower end a push rod 168. The rod 160 is preferably formed of a horizontal section in the shape of a cross (Figure 9d) with four radially directed walls 166a-d, although other configurations may be used. The cross shape is preferred to prevent rotation of the plunger 106 in an aperture 170 similarly (Fig. 10a) in the lid 108, and also to provide a number of cantilevered separate fingers formed in one or more of the four walls 166 for cooperation with other components of piston assembly 104 and reservoir body 100. For example, when observing the upper end of the piston 106, a wall 166a of the cross-shaped rod 160 comprises a plunger release lever 172 defining a separation 174 with the main body of the rod 160. More particularly, the lever 172 of Plunger release extends outwardly from a first position 176 about 2.5 cm (1 inch) below the top plate 162. The release lever 172 continues upward and gradually slopes outward from the remaining portion of the rod 160, and thus defines the separation 174. At the upper end, the lever 172 defines a plunger trigger 180 that extends outwardly. adjacent to a plurality of pull buttons 182. Just below the pull buttons 182, a recess 184 is oriented outward from the lever 172 which terminates in a lower stop 186. The release lever 172 then continues downwardly from the retainer 186 in a substantially constant line until it joins the main vertical profile of the rod 160. The plunger release lever 172 is provided on one of the four walls 166 of the rod 160 in cross shape, and preferably complements a cantilever retraction stop that is formed on the same wall.

Those skilled in the art will recognize that the retraction stop 188 can be formed on one of the other walls, or on more than one wall. The retraction stop 188 begins at a point about 5.1 cm (2 inches) below the top plate 162 and continues downwardly forming a cantilevered finger that diverges from the main portion of the rod 160 through a 190 spacing. The exterior of the retraction stop is preferably vertical and continuous with the remaining portion of the rod 160, and includes a tooth 192 projecting outwardly at the lower end. Just below the retraction stop 188, a pair of piston latch 194 is formed on opposite walls of the cross-shaped rod 160. The piston latches 194 again comprise cantilever fingers that are downwardly dependent from the walls and ending in projections 196 facing outwardly. Preferably, the projections 196 have a sloping upper surface, although a perpendicular surface is shown. The piston latches 194 are preferably formed as extensions of two opposite walls 166a, 166c, of the four defining the cross-shaped rod 160, and more particularly one of the piston latches comprises a projection of the wall 166a including the piston release lever 172 and retraction stop 188. The plunger 106 continues down from the piston latch 194 on the two opposite walls perpendicular to the piston latches 194 to terminate at the lower corners 200. A pair of projection ridges 202 is provided outwardly at the level of the corners 200 and in the same plane as the walls 166a, c in which the piston locks 194 are formed. Finally, the plunger 106 continues downwardly from the shoulders 202 on the push rod 168 centered. The functions of the various element of the plunger will now be described together with the other components of the tank 80.

AP One of the other components of the plunger assembly 104, which is seen in detail in Figures 10a and 10b, comprises the lid 108 for joining the open mouth 124 of the body 100. The lid 108 comprises a circular upper wall 210 having a tube 212 descendant formed integrally dependent on it. The circularity of the upper wall 210 is broken by an orientation tab 214_ that extends outwardly. The down tube 212 continues and ends in a circular reinforcement 216 projecting outwardly. A pair of diametrically opposed locking flanges 218 extend downwardly from the lower edge of the upper wall 210. The locking flanges 218 comprise cantilevered fingers which terminate in protrusions 220 projecting outwardly having lower cam surfaces 222. The aforementioned cross-shaped plunger aperture 170 is formed in an embossed portion 224 of the upper wall 210. The undersurface of the portion 224 embossed at its intersections with the outermost portions of the cross-shaped plunger aperture 170 comprises a slightly cut out bump protrusion. Mobilization boss 226 is adapted to coincide with both plunger release lever 172 and retraction stop 188, as will be described further below.

PISTON The piston 110 is shown in detail in FIGS. 11 and 11b and comprises a tubular body 230 extending upwardly from a flat circular bottom wall 232. The entire piston is approximately 2.18 cm (0.86 inches) in axial height. The lower surface of the lower wall 232 is preferably uniform and makes contact with the shoulders 158 projecting upwards from the lower wall 122 of the tank. The function of the shoulders 158 is to separate the piston 110 from the bottom wall and in this respect, those skilled in the art will recognize that, alternatively, the shoulders may be formed on the underside of the piston 110 instead of on the wall. 122 lower of the deposit. In addition, other piston / chamber configurations may be substituted such as a hemispherical convex piston bottom wall 232 which interacts with a concave or hemispherical bottom wall 122. The lower wall 232 projects radially outward from the tubular body 230 and defines a lower wall 236 of a groove 238, which is completed by an upper wall 240. The slot 238 receives an annular seal 112. An upper portion of the tubular body 230 is interrupted by a pair of diametrically opposed bolt openings 242. The bolt openings 242 are dimensioned to receive the projections 196 of the piston bolts 194. In this way, the plunger 106 and the piston 110 engage. Preferably, the lock openings 242 are recessed at an angle to preferably receive the inclined projections 196 of a more secure coupling, although the interacting surfaces are shown in the drawings perpendicular to the axis of the plunger. One or more circular reinforcements 244 are provided above the slot 238 to retain the cover 116 against contamination. Finally, a vertical guide tube 246 (FIG. 12a) is rigidly formed with the bottom wall and extends up concentrically within the tubular body 230 approximately 0.58 cm (0.23 inches).

DEPOSIT SUPPORT Referring again to FIGS. 4 and 5, support 87 can be fabricated from molded ABS (acrylonitrile-butadiene-styrene) and comprises a lower reservoir retention portion 250, a rear mounting plate 252 and an operating arm 254 of the upper plunger ^ The flat mounting plate 252 includes a pair of elongated vertical slots 256. A pair of resilient and arcuate holding arms 258 extend forwardly from the mounting plate 252 and are joined thereto by means of a bridge portion 260. The retaining arms 258 are of cylindrical cross-section and terminate at opposite vertical edges 262 so that the retaining arms 258 define a partial cylinder of about 270 °. The diameter of the partial cylinder circumscribed by the retaining arms 258 is approximately the same and preferably slightly smaller than the outer diameter of the cylindrical body 100 of the reservoir 80. More particularly, the cylindrical body 100 preferably has an outer diameter of approximately 2.26 cm (0.89 inches), and the inner diameter of the partial cylinder defined by the retaining arms 258 is approximately 2.18 cm (0.86 inches). In addition, the edges 262 are approximately 1.83 cm (0.72 inches) apart so that the cylindrical body 100 can be pressed between them and in engagement with the resilient holding arms 258 to securely hold them thereon. At the upper edge of the partial cylinder defined by the retaining arms 258, the support 87 includes a cavity 264 that continues through the mounting plate 252. Above the cavity 264, the plunger operation arm 254 is formed integrally with the mounting plate 252 on a horizontal wall 266, and includes a pair of reinforcing side walls 268 extending upward therefrom. The side walls are joined at their leading edges by a concave vertical front wall 270. In the upper wall of the front wall 270, a reinforcing mast 272 supports an upper thumb support 274. The thumb support 274 extends substantially perpendicular to the arched front wall 270. Finally, a pair of stop flanges 276 extend forward from the lower end of the forward wall 270. The abutment lips 276 cooperate with the reservoir 80, as will be described later.

DEPOSIT / SUPPORT ASSEMBLY A preferred orientation of the tank 80 assembled to the support 87 is shown in Figures 4 and 5, with the mounting plate 252 in a vertical plane to the rear side of the assembly. The reservoir retaining arms 258 thus extend forward and accept the body 100 with the tabs 127 resting on the upper and arm edges to prevent relative downward movement of the reservoir in the holder 87. The reservoir 80 is placed in the support 87 so that the opposite fins 126 extend back and forth, respectively. The rear fin 126 extends into the cavity 264 with the support 87 to provide a convenient means for orienting the reservoir 80. This orientation also shows the volumetric markings 120 towards the front, and the valve 152 of the closing key 78 oriented forward. In addition, the plunger release lever 172 is oriented forward, so that the plunger trigger 180 is conveniently positioned to drive the plunger assembly 104. Alternatively, the fins 126 are at the same elevation as the lower edges of the tabs 127 and can therefore provide the same stop function of the tabs to prevent relative movement of the reservoir 80 with respect to the retaining arms 258, at least in one direction. Therefore, it is necessary that the tank 80 rotate in a variety of angles around the axis of the tank with respect to the orientation illustrated.

ASSEMBLY OF DEPOSIT The assembled reservoir 80 is seen in FIGS. 4 and 5, and also in its cross section in FIGS. 12 and 13. The cap 108 is preferably fixed to the open mouth 124 of the body 100 by engagement between the immobilization flanges 218 and the teeth. slots 125. Prior to coupling the cap 108 to the body 100, the plunger 106 is inserted into the intersecting opening 170 in the raised portion 224. The lower end of the plunger 106 is then coupled to the upper end of the piston 110. By engaging the plunger 106 and the piston 110, the spring 114 resides concentrically within the tubular body 230 of the piston, and outside the guide tube 246. As shown in the figures, the piston latches 194 perform an inward cam movement by passing the upper end of the tubular body 230 and the spring outwardly within the bolt openings 242 to secure the two components while allowing some axial clearance between the same . - Figures 12a and 12b show the piston assembly 104 in a fully inserted position within the reservoir body 100. In this position, the piston release lever 172 is resiliently deflected outwardly against one of the arms of the piston aperture 170 with the edge of the embossed portion 224 extending into the recess 184, and the retainer 186 captured over the recessed corner. of the enhanced portion. The contamination cover 116 is shown extended surrounding the piston rod 160 and is connected between the falling tube 212 of the cap 108 and the projecting reinforcement 244 outwardly of the tubular piston body 230. A pair of elastomeric retaining rings 280 fix the contamination cover against the reinforcement 216 of the cover 108 and the reinforcement 244 of the piston 110. The contamination cover 116 preferably is a polyethylene pipe having a non-corrugated cross-section which is flexible and will collapse when the piston assembly 104 is retracted from the body 100. When the shoulders 158 contact the bottom wall 232 of the piston 110, a gap G is formed between the piston and the bottom wall 122 of the reservoir. This separation G remains open constantly and provides a passage for discharge fluid. The gap G is determined by the axial height of the shoulders 158, and preferably they are between about 0.127 mm and 0.76T2 mm (0.005-0.030 inches) and more preferably, approximately 0.356 mm (0.014 inches). This small space provides sufficient flow of discharge fluid and at the same time minimizes the volume of fluid necessary for discharge of the reservoir 80 between sampling sequences. The placement of the inlet hole 130 and the outlet orifice 132 also improve the discharge action, as seen in Figure 6b. The inflow flow of the discharge fluid is shown directed outwards by the arrows 228 from the inlet orifice 130. This flow effectively discharges the small volume under the piston 110, and the shoulders 158 are designed to minimize the structure within the volume which can interrupt or slow down this flow. A space S shown in Fig. 12a represents the effective relative axial displacement available between the plunger 106 and the piston 110. In this state, the latch 186 of the release lever engages and deflects upwardly against the cover 108 for defining a first position of the plunger 106 with the piston 110 recessed out of the chamber 102. The spring 114 is compressed between the corners 200 and the outwardly extending flanges 202 and the lower wall 236, thereby deflecting the plunger 106. and to the piston 110. Because the piston 110 is pressed outward, the spring 114 also deflects the plunger upward, at least initially, with respect to the body 100. The piston latches 194 and the openings 242 limit the vertical displacement of the piston 106 relative to the piston 110. When released, the piston 106 will move upward relative to the piston 110 over the space S until the piston bolt projections 196 ison and the openings 242 are engaged, at which time the components move up in battery. Space S is nominally approximately 0.635 mm (0.025 inches). It should be noted that in the position shown at 12a-c, the plunger 106 is not completely recessed out into the guide tube 246, and the plunger can be depressed a further small axial distance, as indicated by the space below the push rod 168. Therefore, S is only the effective axial displacement distance between the plunger 106 and the piston 110 when the plunger is retracted.

FUNCTIONING When used, the reservoir 80 is connected to the tubing of the sampling system 70, as "shown in FIG. 3, before or after being placed on a support post or attached to a patient's arm, for example. respect, the rear mounting plate 252 of the bracket 87 is normally inserted in a tongue and groove manner in a complementary structure that is provided in a vertical hospital support post.The bracket 87 in this manner can be attached to a portable assembly or similar post adjacent the patient and at a convenient elevated position for the nurse or doctor. the reservoir 80 is typically placed in an inverted vertical orientation, with the bottom wall 122 actually above the open mouth 124. Thus , the numerical marks corresponding to the gradations 120 are shown vertical and an increase in value from the upper part to the lower one.The tank 80 and the support 87 can also be attached to the bra the patient with a strip through vertical oblong slots, rolled around the arm and fixed with sailboat or other similar material. In any position, the tank 80 can be maintained by retaining arms 258 with the wings 126 aligned toward and away from the bracket 87, as shown in the drawings, or sideways thereto. Therefore, if necessary, the reservoir 80 can be turned laterally in its assembly to accommodate different distributions of CCUs or operating rooms. Finally, the tank 80 can be completely removed from the support 87 and can operate in a conventional two-hand manner. This flexibility was not previously available in blood sampling tank designs. Before extracting the blood sample, the plunger assembly 104 is in the position shown in Figures 12a-d with the plunger release lever 172 immobilizing the assembly within the body 100. The gap G allows the discharge of fluid through the second intubation line 82 to pass into the inlet hole 130 and below the piston 110 to exit the volume into the reservoir 80 through the outlet orifice 132. The discharge fluid cleans the residual blood from the reservoir 80 and thus prevents coagulation or other undesirable consequences of static blood. With the guidance hole 130 inlet, the fluid entering the gap G in a direction perpendicular to the piston 110 causes immediately vent or disperses radially outwardly in a thin sheet. Figure 6b illustrates the preferred flow vectors 228 of the fluid entering the gap G from the inlet orifice 130. Hole position input 130 allows discharge effect as portions of the sheet of fluid are directed to the peripheral wall of the chamber 102, while some are directed to the output port 132. As seen in Fig. 12c, the gap G is relatively constant between the piston 110 and the bottom wall 122, except for a peripheral channel 284 created above the non-obstructed peripheral band 159 surrounding the shoulders 158 V This channel 284 it is formed by the circumferential termination of the bottom wall 232 of the piston 110 and the release space formed by the stepped lower edge of the seal 112 before the first seal sweep. The discharge fluid is not directed to the outlet orifice 132 and enters the peripheral channel 284 and continues circumferentially around the chamber 102, towards the exit orifice 132. The outlet orifice 132 opens to the peripheral channel 284 and thus effectively drains the fluid flowing circumferentially from the channel as well as the fluid that enters more directly from the inlet 130. In addition, the shoulders 158 are relatively small and therefore a minimum amount of discharge fluid is needed to maintain the reservoir 80 reservoir. Because the discharge fluid continues along the intubation line 74 passing the sites 98a and 98b of sampling inside the patient, a minimum of fluid is desired to avoid overdilution of the bloodstream of the patient. In designing the appropriately dimensioned G-separation, numerous factors such as the diameter of the reservoir body 100, the flow velocity and the flowing fluid pressure, the size of the inlet orifice 130, the time period that has to be taken into consideration must be taken into consideration. the deposit will be connected in the pressure monitoring system, etc. Desirably, under preferred operating conditions, the separation G is such that a thin sheet of 360 ° of fluid is directed from the inlet 130 into the peripheral wall of the chamber 102 and into the interior of the channel 284. In one embodiment exemplary, the gap G is less than the orifice of the inlet port 130, which is about 1.78 mm (0.07 inches), but more desirably is between about 0.127 and 0.762 mm (0.005-0.030 inches) for a deposit 80 which has an inner chamber diameter of approximately 1.97 cm (0.77 inches). The input fluid pressure range will be determined by the operating specifications of the pressure transducer 90, and is typically not greater than 300 mm Hg, and desirably approximately 250 mm Hg. As mentioned, this pressure is generated by an inflatable bag that surrounds the fluid supply bag. The flow rate of the discharge fluid through the system 70 between the blood samples is typically between 50-100 cc / minute. When a blood sample is to be taken, the discharge flow of the infusion fluid is stopped, so that with the use of a stopcock valve (not shown) upstream of the reservoir 80. The nurse or the doctor then the tank 80 is held with a finger or thumb on the thumb support 274 on the top of the support 87 and the other finger or thumb below the plunger trigger 180 of the plunger release lever 172. By pressing the two surfaces together, the plunger release lever 172 pivots inwardly due to the gap 174. At some point, the retainer 186 is released from the underside of the plunger aperture 170 thus crossed, releasing the assembly 104 from plunger so that it moves upwardly within the body 100. Therefore, the pressing operation with one hand simultaneously releases the plunger assembly 104 and begins its movement within the chamber 102 of the reservoir. The plunger assembly 104 is retracted from the interior of the body 100 by continuous pressure of pressure between the thumb support 274 and the plunger trigger 180. The body 100 is restricted from its upward movement by the abutment lips 276 on the support 87. The pressure operation with one hand to retract the plunger assembly 104 is a major advantage of the present invention, and releases the other hand of the physician to meet other needs of the patient. In addition, it does not need to grasp the reservoir body 100 to retract the piston assembly 104, as would normally be the case with conventional syringe-like pulling devices of this type. Finally, the force required to retract the plunger assembly 104 is the same as with a pull-type syringe device, but it is easier to generate with a pressing operation as opposed to "a pulling operation." Therefore, Nurses or physicians with less strength can easily operate the reservoir 80. The plunger assembly 104 can be retracted to remove a variable amount of fluid sufficient to pull pure blood past both the sampling sites 98a and 98b.This volume differs in different hospital facilities, but is typically 12 cc in an operating theater environment and 55 cc in the CCU The reservoir body 100 illustrated, as described above, has the capacity of 12 cc when the plunger assembly 104 retracts completely. Figures 13a and 13b show the piston assembly 104 in a second position completely retracted with respect to the reservoir body 100. In this position, the piston release lever 172 is prevented from retracting further from the body 100 by interference between the tooth 192 projecting outward from the retraction stop 188 and the trimmed edge 226 (Figure 12d) of the raised portion 224 of the cap 110. The total displacement of the plunger 106 is shown as T in Figure 12a, and is approximately 4.39 cm (1.73 inches) in the exemplary embodiment. This distance will vary based on the volume extracted within the reservoir, and the diameter of the chamber 102, but the small distance is ergonomically designed to facilitate single-hand operation by small-sized physicians. Desirably, the distance T is no greater than the distance of the thumb and the index of the smallest physician who can operate the system. The nurse or physician is notified of the complete retraction of the plunger assembly 104 by the positive interaction between the tooth and the lid 110. Of course, those skilled in the art will recognize that different stops can be provided for flexibility in sequential stopping of the tooth. volumes of fluid through the first intubation line 74. The contamination shield 116 collapses when the plunger assembly 104 retracts completely. It will be noted that the seal 112 prevents blood and other fluid from moving upwardly into the region within the body 100 and around the piston assembly 104. To further protect against contamination of blood within the body 100 below the piston 110, the contamination cover 116 separates the internal components of the piston assembly 104 from the interior walls of the reservoir 100, which are in contact with the volume of the fluid and finally infused back to the patient. After complete retraction of the plunger assembly 104, the closing key 78 is closed, and the blood samples are taken at the sites 98a and 98b. This operation preferably takes place with a blunt-tipped cannula syringe, and is well described in the prior art. It should be noted, however, that a single sampling site can be used, and other sampling devices such as sharp-tipped cannulas can also be used, with less safety for the nurse or physician. After the samples have been taken, the closing key 78 is opened and the volume within the reservoir 80 is infused back into the patient. This is accomplished by depressing the plunger assembly 104 within the body 100. The nurse or physician places the thumb or one finger on the thumb support 164 of the upper plate 162, and the other finger of the same hand on the upper plate 162. bottom side of the fin 126 extending forward, when pressing with the thumb and the other finger together, the piston assembly 104 moves downwardly inside the body 100. The plunger assembly 104 continues to descend until the piston 110 makes contact with the shoulders 158. in the lower wall 122, at which point the piston 110 stops moving downwards, but the plunger 106 continues. The spring 114 is compressed by the outwardly extending flanges 202 and the lower wall 236 until the retainer 186 in the plunger operation lever 172 is immobilized with the underside of the plunger opening 170. The provision of the spring 114 provides several advantages to the blood sampling system 70 of the present invention. First, the spring 114 biases the HDTiacia piston down into contact with the shoulders 158 in the bottom wall 122. This ensures a constant G-clearance for fluid to flow through the inlet hole 130 into the outlet orifice 132 with the concomitant discharge advantages described above. The spring 114 also eliminates the need for narrow manufacturing tolerances of the height of the components of the piston assembly 104, which would otherwise be the case if the piston 110 is biased and the shoulders 158.

That is, the spring 114 allows the size range of the gap G to be determined only by the tolerances associated with the shoulders 158. Any problem of tolerance stacking in the making of the parts of the piston assembly 104 is compensated and covered by spring 114. Therefore, the parts can be made to wide tolerances, which reduces the costs of manufacturing the reservoir 80. Finally, the spring 114 provides a particular frequency response of the plunger assembly 104 so that it is optimized monitoring "pressure by the transducer 90. That is, the length and character of the pipe and the sampling holes between the reservoir 80 and the patient determine a particular volume with the sampling system 70, and the spring constant of the spring 114 interacts with this volume, or the fluid mass if desired, to affect the damping of the fluid system.This control of the damping factor is useful to optimize the operation of pressure measurement. In a further embodiment of the present invention, which is shown schematically in Figure 14, the speed of the spring, of the spring 114 may be adjustable. In this embodiment, a reservoir 286 includes a plunger 288 which is threadably coupled to a spring yoke 290 by means of a threaded rod 292. A spring 294 is placed in compression between the yoke 292 and a piston 296. The relative position of the yoke 292 determines the preload in the spring 294 thus the force that is needed to raise the piston 296 when the plunger 288 is immobilized in the deposit as in the previous. This control allows the physician to optimize the dynamic response by performing a frequency response test and then adjusting the system's damping coefficient if the frequency response is not adequate. Figure 15 illustrates another one hand reservoir 300 for use in a blood sampling system. The reservoir 300 comprises an outer housing 302 having an oval cross section and a pair of opposed elongated slots 304 on the narrow sides. The slots receive extensions outward from an inner housing 306 that also has an oval cross section which is reciprocal linearly within the outer housing 302. The inner housing 306 includes an inner chamber (not shown) with an inlet hole 308 and an outlet hole 310 communicating therewith. A pair of ring 312 is rigidly attached for the thumbs to the inner housing 306 projecting outwards, through the slots 304. The operation of the tank 300 is better described with respect to Figures 16a-c which illustrate a deposit 314 identical except that the rings 312 are placed with the flanges 316. Otherwise, the similar elements receive the same numbers.

As seen in Figures 16a-c, the reservoir 314 includes a top cover 318 fixed on an open upper end of the outer housing 302 with a piston 32CL-rigidly attached thereto and extending within a chamber 322 of variable volume of the accommodation 306 interior. A seal 324 is housed in the distal end of the piston 320 and defines an end of the chamber 322 of variable volume opposite the inlet and outlet orifices 308, 310. The contamination cover 326 extends between an upper end of the inner housing 306 and the seal 324. The reservoir 314 operates in a manner similar to the reservoir 80 previously described, and is preferably installed in a pressure monitoring line with the orifice 308 of inlet to the pressure transducer and the fluid supply, and the outlet port 310 to the sampling sites and to the patient. Figure 16a shows the inner housing 306 in a first position with respect to the outer housing 302, where the piston 320 is in contact with the lower wall 328 of the chamber 322. Desirably, a small separation is maintained between the piston 320 and the lower wall 328 of the chamber to allow the flow of a discharge fluid therethrough, as previously described. In this regard, projections may be formed on the piston 320 or the lower wall 328 of the chamber to form the gap. In addition, the inlet hole 308 is shown as in the above entering the chamber perpendicularly with respect to the bottom wall 328 and in a position separated from the periphery to improve the discharge effect. In contrast to the previous embodiment, however, the outlet orifice 310 is still positioned in the periphery but is parallel to the lower wall 328 of the chamber. Figure 16b shows a second position of the inner housing 306 with respect to the outer housing 302 where the piston 320 is no longer in contact with the lower wall 328 of the chamber and a volume of fluid 330 has been withdrawn within the chamber 322. The lower wall 328 ~ is stopped against the lower surface 331 of the outer housing 302. In this step, the physician closes the closure key 332 and takes blood samples from one or more sites between the reservoir 314 and the patient. The reservoir 314 may include features such as a spring loaded piston, as previously described. The reservoir 314 differs from the reservoir 80 previously described by the lack of a mounting bracket for the support post or the patient's arm. Of course, such a structure can be provided for the reservoir 314 fixed to the inner or outer housing. The one-hand pressure operation of reservoir 314 is maintained, however, without a separable support. With reference to Figure 16a, the force arrows 334 show the moving position of the opposing thumb and finger to move the inner housing 306 from its first position to its second position in Figure 16b. Conversely, Figure 16b illustrates the force arrows 336 that apply the opposite thumb and fingers to move the inner housing 306 from its second position to its first position. It should be understood that the examples and embodiments described herein and shown in the drawings represent only the currently preferred embodiments of the invention, and are not intended to exhaustively describe in detail all possible modalities in which it may take physical form. the invention. In fact, various modifications of additions to such modalities can be made without departing from the spirit and scope of the invention. For example, although the present sampling system is described and is particularly for venous or arterial blood sampling, other body fluids such as urine may be mixed, and the device may have other uses for example in wound drainage. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers.

Claims (51)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A fluid sampling system, characterized in that it comprises: a conduit pipe with a proximal portion adapted to be supplied with a fluid, and a distal portion adapted to be in communication with a fluid system of a patient; a reservoir assembly having a variable volume chamber with an inlet opening open to the proximal portion of the conduit tubing, and an outlet port open to the distal portion of the conduit tubing; a piston that can be moved inside the chamber to vary the volume of the chamber; a first pair of pressing surfaces in the reservoir assembly facing away from each other and adapted to move the piston relative to the chamber to increase the volume within the chamber; a second pair of depressed surfaces in the reservoir assembly facing away from each other and adapted to move the piston relative to the chamber to decrease the volume within the chamber, wherein the fluid can be withdrawn into the chamber and expelled from the chamber. same by actuating the first and second pair of pressing surfaces, respectively.

2. The system according to claim 1, characterized in that the reservoir assembly comprises a syringe-like device having an axis with the entry hole located at an axial end of the chamber and the piston is axially displaceable by actuation of the first or second for pressing surfaces to increase or decrease respectively the volume of the camera.

3. The system in accordance with the claim 2, characterized in that the chamber is centered around the axis, and the inlet hole is located offset at an axial end.

4. The system according to claim 2, characterized in that the piston includes a wall facing the entrance orifice and that partially defines the volume of the chamber, and the entry orifice is oriented substantially perpendicular with respect to the face.

5. The system according to claim 2, characterized in that the reservoir assembly comprises the syringe-like device and a holder for mounting the assembly to an external support, the syringe-like device is attached to a mounting bracket, and wherein one of a first pair of pressed surfaces is on the support.

6. The system according to claim 5, characterized in that the syringe-like device is removably attached to the mounting bracket.

7. The system according to claim 5, characterized in that the mounting bracket includes a retaining portion and the syringe-like device has a body defining a chamber therein, the body is received in the retaining portion and the axial movement with respect to it.

8. The system according to claim 5, characterized in that the syringe-like device further includes a body defining a chamber within a plunger assembly comprising the piston at a first end and a plunger at a second end extending out of the body, wherein the plunger defines the other of the first pair of pressurized surfaces to cooperate with one of the supports.

9. The system according to claim 8, characterized in that the plunger defines one of a second pair of pressing surfaces.

10. The system according to claim 9, characterized in that the body includes a member that extends generally radially outwardly, which defines the other of the second pair of pressurized surfaces to cooperate with one on the plunger.

11. A method for sampling a fluid using a reservoir assembly and a sampling hole located in a line attached to a catheter in communication with a patient's fluid system, the method is characterized in that it comprises: pressing a first pair of pressing surfaces in the tank assembly, the first pair of pressing surfaces are oriented in opposite directions, so that they move a piston inside a chamber of variable volume defined between the reservoir assembly and extract a fluid from the patient through the sampling hole into the chamber; sample the fluid from the sampling hole; and pressing a second pair of pressurized surfaces in the reservoir assembly, the second pair of depressed surfaces is oriented in opposite directions, so as to move the piston within the variable volume chamber and infuse fluid from the chamber through the chamber. sampling hole inside the patient.

12. The method according to claim 11, characterized in that the reservoir assembly comprises a syringe-like device having an axis, wherein depressing the first or second pair of pressurized surfaces moves the piston axially to increase or decrease respectively the volume of the camera.

13. The method according to claim 12, characterized in that the reservoir assembly comprises a syringe-like device and a holder for mounting the assembly to an external holder, the syringe-like device is attached to a mounting bracket, and wherein one of the first pair of pressed surfaces is on the support.

14. The method according to claim 13, characterized in that the mounting bracket includes a retaining portion and the syringe-like device has a body defining the chamber therein, the body is received in a retaining portion and is maintained preventing the axial movement with respect to it.

15. The method according to claim 13, characterized in that the syringe-like device includes a body defined by the chamber within a plunger assembly comprising the piston at a first end and a plunger at a second end extending out of the body , wherein the plunger defines the other of the first pair of pressurized surfaces to cooperate with one of the mounting brackets.

16. The method according to claim 15, characterized in that the piston defines one of the second pair of pressing surfaces.

.17. The method according to claim 16, characterized in that the body includes a member that extends generally radially outwardly which defines the other of the second pair of pressurized surfaces to cooperate with one on the plunger.

18. A reservoir for use in a fluid sampling system, characterized in that it comprises: a reservoir body defining a chamber therein, a piston having a piston wall facing the chamber and movable within the body from a first position a a second position to vary the volume of the camera; a fluid inlet port and a fluid outlet port open to the chamber; a structure on the chamber or piston which maintains a minimum separation between the piston wall and the body when the piston is in the first position, the separation defines a volume in which the inlet and outlet holes are communicated to allow the fluid flowing between them; and a deflection member which urges the piston wall to the first position.

19. The reservoir according to claim 18, characterized in that the reservoir comprises a syringe-like device, having an axis with an entrance hole located at an axial end of the chamber and the piston is axially displaceable along the length of the chamber. axis between the first and second positions.

20. The reservoir according to claim 19, characterized in that the chamber is centered around the axis and the inlet hole is located offset at an axial end.

21. The reservoir according to claim 18, characterized in that the wall of the piston is oriented towards the inlet orifice and the inlet orifice is oriented substantially perpendicular with respect to the wall of the piston.

22. The reservoir according to claim 18, characterized in that it further includes a reciprocating plunger assembly within the reservoir body comprising the piston at a first end and a plunger at a second end extending out of the body, wherein the limb Deviation is placed between, and drives separating the piston and the piston.

23. The deposit in accordance with the claim 22, characterized in that the body and plunger assembly cooperate to form a syringe-like device with the reciprocating plunger assembly along an ee defined by the body, and wherein the biasing member substantially acts on the axial direction.

24. The deposit in accordance with the claim 23, characterized in that the plunger includes locking detents which cooperate with the openings in the piston to couple the plunger and the piston together while permitting relative axial movement therebetween.

25. The deposit in accordance with the claim 24, characterized in that it also includes a complementary structure in the plunger and in the body which maintains the plunger in a retracted position that urges the wall of the piston to the first position.

26. The deposit in accordance with the claim 25, characterized in that it further includes a trigger on the plunger which releases the plunger from its retracted position.

27. The deposit in accordance with the claim 26, characterized in that the trigger comprises a cantilevered lever member biased outwardly against an edge when the plunger is in the retracted position, the edge is fixed with respect to the body, the lever member includes a detent which interferes with the edge and holds the plunger in the retracted position until the lever member is moved inwardly.

28. The reservoir according to claim 18, characterized in that the structure which maintains a minimum separation between the wall of the piston and the body when the piston is in the first position, comprises a projection on the wall of the piston.

29. The deposit in accordance with the claim 18, characterized in that the structure which maintains a minimum separation between the wall of the piston and the body when the piston is in the first position, comprises a projection on an interior wall of the body facing the wall of the piston.

30. The reservoir according to claim 29, characterized in that there are three projections on the inner wall generally distributed uniformly around a circle - spaced apart from the side walls of the chamber.

31. The deposit in accordance with the claim 18, characterized in that the inlet orifice is in fluid communication with a pipe that is directed from a fluid source and the outlet orifice is in fluid communication with a pipe that is directed to a fluid system of a patient.

32. The deposit in accordance with the claim 18, characterized in that the magnitude of the deflection member is adjustable.

33. The reservoir according to claim 32, characterized in that it also includes a plunger with reciprocating movement capability inside the reservoir body and coupled to the piston with an axial play between them, wherein the deflection member is a spring placed between a part of piston drive and plunger.

34. A method for unloading a reservoir using a fluid sampling system, characterized in that it comprises: providing a reservoir having a chamber and a displaceable piston having a piston wall facing the chamber and movable within the body to vary the volume of the camera; connect a proximal portion of the intubation between a source of discharge fluid and an inlet to the variable volume chamber; connecting a distal portion of the intubation between a fluid system of a patient and an exit to the chamber of variable volume; diverting the piston in a first position within the variable volume chamber with the piston wall adjacent to the inlet and outlet holes; and maintain a minimum separation between the piston wall and the chamber when the piston is in the first position with the structure either the chamber or the piston, the separation defines a volume to which the inlet and outlet orifices are communicated and allow that the fluid flows from the proximal position of the intubation to the distal portion of the intubation.

35. The method in accordance with the claim 34, characterized in that the reservoir comprises a syringe-like device having an axis with the entry hole located at an axial end of the chamber and the method includes axially displacing the piston along the axis within the first position.

36. The method according to claim 35, characterized in that the chamber is centered around the axis and the inlet hole is located offset to an axial end, the method includes flowing discharge fluid into the chamber through the inlet orifice when the piston is in the first position.

37. The method according to claim 34, characterized in that the wall of the piston of the piston is oriented towards the inlet orifice and the inlet orifice is oriented substantially perpendicular with respect to the wall of the piston, the method includes flowing discharge fluid inside the chamber through the inlet port when the piston is in the first position, where the discharge fluid makes contact with the piston wall perpendicularly and disperses within the separation.

38. The method according to claim 34, characterized in that it includes a plunger with reciprocating movement capability within the reservoir body and coupled to the piston with axial play therebetween, wherein the method includes adjusting the magnitude of the deflection member.

39. The method according to claim 34, characterized in that it further includes a plunger assembly with reciprocating movement capability inside the tank body comprising the piston at a first end and a plunger on a second end extending out of the body, in wherein the diverting member is positioned between and urges apart the piston and the plunger, and wherein the body and plunger assembly cooperate to form a syringe-like device with reciprocating reciprocating piston assembly along an axis defined by the body, the method includes deflecting the piston in an axial direction to a first position.

40. The method according to claim 39, characterized in that it includes coupling the plunger and the piston together and at the same time allowing relative axial movement between them.

41. The method according to claim 39, characterized in that it includes holding the plunger in a retracted position or urging the piston to the first position.

42. The method according to claim 41, characterized in that it further includes actuating a trigger on the plunger to drive the plunger from the retracted position.

43. The method according to claim 34, characterized in that it includes maintaining the minimum separation between the wall of the piston and the body when the piston is in the first position, with a projection on the wall of the piston.

44. The method according to claim 34, characterized in that it includes maintaining a minimum separation between the piston wall and the body when the piston is in the first position with a projection on an interior wall of the body facing the piston.

45. A reservoir for use in a fluid sampling system, characterized in that it comprises: a reservoir body defining a variable volume chamber therein, the body having a peripheral wall and a lower wall; a fluid inlet orifice perpendicular through the lower wall of the body and open to the chamber; a fluid outlet opening open to the chamber; a piston movable within the body from a first position adjacent to the bottom wall, to a second position further away from the bottom wall to increase the volume of the chamber, the piston has a pressure surface which is separated from the bottom wall to form a narrow gap between them when the piston is in the first position, the fluid inlet and outlet holes open towards the separation; and a seal which surrounds the pressure surface and which provides a first airtight seal to the fluid between the piston against the peripheral wall of the chamber, wherein the fluid entering the chamber through the inlet port when the piston is in the chamber. first position, is generally directed in a 360 ° sheet through the lower wall and towards the peripheral wall of the chamber.

46. The deposit in accordance with the claim 45, characterized in that the pressing surface is substantially flat and is placed parallel to the lower wall.

47. The reservoir according to claim 45, characterized in that it includes a projection on the pressure surface which makes contact with the lower wall and forms the separation.

48. The reservoir according to claim 45, characterized in that it includes a projection on the surface of the lower wall which makes contact with the pressure surface and forms the separation.

49. The reservoir according to claim 48, characterized in that there are three projections on the lower wall generally distributed uniformly around a circle separated inwards from the peripheral wall.

50. The reservoir according to claim 45, characterized in that the pressure surface is spaced between approximately 0-13 mm and 0.76 mm (0.005-0.030 inches) from the lower wall, when the piston is in the first position.

51. The reservoir according to claim 45, characterized in that the outlet orifice of the fluid extends perpendicularly through the lower wall of the body.