Medical devices to assist with needle placement

Abstract

The present invention relates to a medical device used to aid in successful placement of a needle tip within a blood vessel. The medical device comprises a body defining a vacuum chamber therein, a port for engaging a hub of a needle, a fluid passageway through the port from outside the body to the vacuum chamber inside the body, and a means for generating audio / tactile feedback to a user acted upon by a vacuum within the vacuum chamber. The means for generating audio / tactile feedback includes an abutment arm and a complementary abutment surface engaged by the abutment arm. The abutment surface has a rib along its length opposing the abutment arm. The vacuum within the vacuum chamber moves one of the abutment arm and the abutment surface relative to the other, whereby the abutment arm releasably engages the rib to generate the audio / tactile feedback.

Description

[Technical field]

[0001] The present invention relates to medical devices, and more particularly to medical devices used to aid in successful placement of a needle tip within a blood vessel. [Background technology]

[0002] One such medical device is disclosed in Applicant's own Patent Cooperation Treaty (PCT) patent application, U.S. Patent No. 6,333,636, the entire contents of which are incorporated herein by reference, including, inter alia, the discussion of the problems addressed by these medical devices, their features and advantages.

[0003] US Patent No. 5,399,633 discloses a medical device that provides rapid and useful feedback to a medical practitioner as the practitioner accesses a central vein during central line insertion. Furthermore, the medical device is less cumbersome than known devices, simplifies known techniques for needle placement, and is less expensive to manufacture than many alternatives.

[0004] However, it is envisioned that there are many aspects of these medical devices that could still be improved. For example, it would be advantageous to further improve the speed at which the medical practitioner is notified of successful placement of the needle tip into the vein, thereby preventing the medical practitioner from exiting the vein by penetrating the back wall of the vein. Secondly, it would be advantageous to provide more frequent and more prominent feedback than has been the case thus far. Thirdly, it would be advantageous to provide a medical device that is even more sensitive in detecting when the needle tip has penetrated the vein wall. Fourthly, it would be advantageous to provide a device that is easier to activate so as not to move the needle when it is believed to be in or close to the vein. Fifthly, it would be possible to manufacture the device using standard techniques. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2020 / 079251 Brochure Summary of the Invention [Problem to be solved by the invention]

[0006] It is an object of the present invention to provide a medical device that overcomes at least one of the shortcomings of known devices and offers consumers a useful alternative choice. [Means for solving the problem]

[0007] In accordance with the present invention there is provided a medical device for use in assisting in successful placement of a needle tip within a blood vessel, the medical device comprising: a body defining a vacuum chamber therein, the body having a port for engaging a hub of a needle, the port defining a fluid passageway from outside the body to the vacuum chamber within the body; and means for generating at least one of audio and tactile feedback to a user acted upon by a vacuum within the vacuum chamber, the means for generating feedback including an abutment arm and a complementary dedicated abutment surface operatively engaged by the abutment arm, the abutment surface having a plurality of closely spaced abutment members disposed along its length and opposing the abutment arm, the abutment surface operable to move one of the abutment arm and abutment surface relative to the other of the abutment arm and abutment surface, thereby generating feedback by the abutment arm releasably engaging at least one of the abutment members of the abutment surface.

[0008] By having such a medical device, the means for generating audio / tactile feedback provides faster and more frequent recognizable feedback and is therefore easier to detect. This increases the likelihood that the medical practitioner will recognize an indication that the needle tip is in the blood vessel and avoids the possibility that the medical practitioner will pass the needle tip through the vein and out the other side of the vein. The abutment member is preferably provided by a rib. Alternatively, the abutment member can be provided by other protrusions, cavities, depressions or uneven surfaces that the abutment arm contacts. The means for generating audio / tactile feedback no longer relies on the scraper arm passing against the folds of the bladder (which are relatively far apart and require a large amount of blood to flow into the device to provide feedback to the medical practitioner). This provides a more sensitive, faster and clearer indication that the needle tip is correctly located.

[0009] In one embodiment of the present invention, a medical instrument is provided in which the abutment arms and abutment surfaces are disposed inside the body. This is considered a useful embodiment of the present invention. By disposing the abutment arms and abutment surfaces inside the body, a more compact instrument is provided.

[0010] In one embodiment of the present invention, a medical device is provided that includes a valve in the fluid passageway intermediate the exterior of the body and a vacuum chamber operable to selectively apply a vacuum to the port. This is considered a particularly preferred embodiment of the present invention. By having such a valve, the device can be primed after the needle tip enters the body and before entering the blood vessel. This prevents the inadvertent introduction of air into the device and the corresponding loss of vacuum before the needle tip is inserted into the patient's body.

[0011] In one embodiment of the present invention, a medical device is provided with a releasable latch operable to control the application of vacuum to a port, which is also seen as a useful method of priming the device after insertion of the needle tip into a patient's body and prior to insertion of the needle tip into a blood vessel.

[0012] In one embodiment of the present invention, a medical device is provided in which the vacuum chamber comprises an elongated, collapsible bellows. The bellows is preferably cylindrical, although other shapes are readily envisioned, such as oval, square, rectangular, triangular, pentagonal, hexagonal, or other multi-sided cross-sections. Having an elongated bellows allows the bellows to fold in a compact and predictable manner.

[0013] In one embodiment of the present invention, a medical device is provided in which the collapsible bellows is constructed from an elastically deformable material, which is also seen as a useful aspect of the present invention since the bellows will attempt to return to its normal shape, thereby providing the vacuum force.

[0014] In one embodiment of the present invention, a medical device is provided with a spring operable to expand a collapsible bellows. The spring further assists in creating a vacuum suction force through the port resulting in a more usable device. Additionally, the spring is operable to overcome friction between the abutment arms and abutment surfaces, ensure uniform expansion within the bellows, and encourage the bellows to expand in a desired direction.

[0015] In one embodiment of the present invention, a medical device is provided in which the bellows has a pair of substantially planar opposing end plates that allow the end plates to fit together, thereby reducing the amount of air in the collapsed vacuum chamber and resulting in a more responsive device that reacts more quickly to the entry of blood into the needle and the resulting change in pressure.

[0016] In one embodiment of the present invention, a medical device is provided in which the bellows is provided with an internal plug operable to substantially fill the void within the bellows and minimize the amount of air within the bellows when the bellows is in a collapsed configuration. Again, by providing a plug that fills the void within the collapsed bellows, the amount of air within the collapsed vacuum chamber is reduced, resulting in a more responsive device that responds more quickly to the ingress of blood into the needle and the resulting pressure changes.

[0017] In one embodiment of the present invention, a medical device is provided in which guidance means for the bellows are provided to control the direction of movement of the outermost ends of the bellows, and thus the shape of the bellows, as the bellows transition to or from an expanded configuration and to or from a contracted configuration. By controlling the way in which the bellows deforms and returns to its rest configuration, the device can provide more diverse and controlled warning notifications than would otherwise be possible. Furthermore, this avoids the possibility of the bellows "getting jammed" as it returns to its rest configuration.

[0018] In one embodiment of the present invention, a medical device is provided in which the bellows has a dual skin, an inner bellows and an outer bellows. This is considered a particularly advantageous embodiment of the present invention. By having a dual skin bellows, a greater vacuum force is achieved, air pockets in the bellows are greatly reduced when compressed, and the internal volume of the bellows is reduced compared to a single skin bellows with the same external dimensions. The internal bellows effectively forms a plug, reducing air gaps. This results in a more accurate and sensitive device, as well as a more compact device that is easier for medical personnel to handle.

[0019] In one embodiment of the present invention, a medical device is provided with a releasably removable vacuum chamber. This is considered a useful alternative method of providing vacuum. Instead of using a bellows, a vacuumed container can also be connected to the body of the medical device to provide the vacuum. This allows the size of the vacuum to be chosen precisely as required.

[0020] In one embodiment of the present invention, a medical device is provided with multiple abutment arms, which can increase the amount of feedback to the user and provide a more prominent warning sign that the needle tip is in the blood vessel.

[0021] In one embodiment of the invention, a medical instrument is provided with a plurality of complementary abutment surfaces. In one embodiment of the invention, a medical instrument is provided with a dedicated abutment surface on each abutment arm.

[0022] In one embodiment of the present invention, a medical device is provided in which a valve is actuated by applying a force perpendicular to the longitudinal axis of a needle connected to a body. In one embodiment of the present invention, a medical device is provided in which a latch is actuated by applying a force perpendicular to the longitudinal axis of a needle connected to a body. These are considered useful because applying a force perpendicular to the longitudinal axis of a needle connected to a body does not advance or retract the needle by switching a valve or latch. This prevents accidental over-insertion and over-retraction of the needle, which can greatly improve patient safety.

[0023] In one embodiment of the present invention, a medical device is provided in which a fluid passage is defined by a body portion constructed of silicone rubber to which a valve engages. Silicone rubber has a relatively soft Shore A hardness and therefore can deform relatively easily to block the fluid passage in the body and maintain a vacuum in the bellows. This is considered useful because the valve is easily opened so that switching the valve does not advance or retract the needle. This prevents inadvertent over-insertion and over-retraction of the needle.

[0024] In one embodiment of the invention, the volume of the fluid passage between the opening of the needle hub and the closing point of the valve is 0.05 ml. Preferably, the volume of the fluid passage between the opening of the needle hub and the closing point of the valve is less than 0.05 ml. The fluid passage is generally limited in length and diameter to further limit any voids.

[0025] In one embodiment of the present invention, there are inserts in the fluid passages on either side of the valve to further reduce the effective open cross-sectional area of ​​the fluid passages to a similar cross-sectional area of ​​the needle attached to the device.

[0026] In one embodiment of the present invention, a medical device is provided with a vacuum between 150 mmHg (20 kPa) and 250 mmHg (33.3 kPa), which is believed to be particularly suitable for obtaining a rapid response from the device and for early identification of needle tip placement within the vein.

[0027] In one embodiment of the present invention, a medical device is provided in which the valve has a Shore hardness of 10-55 Shore A.

[0028] In one embodiment of the present invention, a medical device is provided in which the port is provided with a side port branching off therefrom, the side port having a closure thereon. Again, this is believed to be a particularly useful aspect of the invention. The side port can be used to introduce a wire through the side port, through the port and along with the needle, allowing for the rapid performance of the Seldinger or modified Seldinger technique.

[0029] The invention will now be more clearly understood from the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0030] [Figure 1] 1 is a perspective view of a medical device according to the present invention; [Diagram 2] FIG. 2 is another perspective view of the device of FIG. 1 with the bellows and compression spring removed. [Diagram 3] FIG. 2 is a side cross-sectional view of the device of FIG. 1. [Figure 4] FIG. 4 is an enlarged view of the circled portion B in FIG. 3. [Diagram 5] FIG. 4 is an enlarged view of the circled portion C in FIG. 3. [Figure 6] FIG. 2 is a perspective view of a medical instrument similar to FIG. 1 with the bellows in an expanded configuration. [Figure 7] FIG. 4 is a side cross-sectional view of the medical device similar to FIG. 3, with the bellows in an expanded configuration. [Figure 8] FIG. 3 is a view similar to FIG. 2 with the plunger in a retracted configuration. [Figure 9] FIG. 2 is a rear perspective view of a second embodiment of a medical device according to the present invention. [Figure 10] 10 is a side cross-sectional view of the medical device of FIG. 9. [Figure 11] 10 is a side cross-sectional view of the medical device of FIG. 9 with the bellows removed for clarity. [Figure 12] FIG. 10 is a rear perspective view of the medical instrument of FIG. 9 with the bellows removed for clarity. [Figure 13] 10 is a front perspective view of the medical instrument of FIG. 9 with the bellows and compression spring removed. [Figure 14] FIG. 14 is a rear perspective view similar to FIG. 13, but with the bellows and compression spring removed. [Figure 15] FIG. 13 is a rear perspective view of a third embodiment of a medical device according to the present invention. [Figure 16] FIG. 16 is a cross-sectional view of the medical device of FIG. 15. [Figure 17] FIG. 16 is an end view of the medical device of FIG. [Figure 18] FIG. 18 is a cross-sectional view taken along line BB in FIG. 17. [Figure 19] FIG. 18 is a cross-sectional view taken along line AA in FIG. 17. [Figure 20] FIG. 13 is a rear perspective view of a fourth embodiment of a medical device according to the present invention. [Figure 21] FIG. 21 is a cross-sectional view of the medical device of FIG. 20 excluding the valve. [Figure 22] 21 is another cross-sectional view of the medical device of FIG. 20 excluding the valve. [Figure 23] FIG. 23 is an enlarged view of the circled portion C in FIG. 22. [Figure 24] FIG. 21 is a cross-sectional view of the medical device of FIG. 20. [Diagram 25] 21 is another cross-sectional view of the medical device of FIG. 20. [Figure 26] FIG. 26 is an enlarged view of the circled portion C in FIG. 25. [Figure 27] FIG. 11 is a front view of a fifth embodiment of a medical device according to the present invention. [Figure 28] FIG. 28 is a perspective view of the medical device of FIG. 27. [Figure 29]FIG. 28 is a perspective view of the medical device of FIG. 27. [Diagram 30] FIG. 28 is a perspective view of the medical device of FIG. 27. [Diagram 31] FIG. 28 is an end view of the medical device of FIG. 27. [Diagram 32] FIG. 13 is a rear perspective view of a sixth embodiment of a medical device according to the present invention. [Diagram 33] FIG. 33 is a side cross-sectional view of the medical device of FIG. 32. [Diagram 34] FIG. 13 is a rear perspective view of a seventh embodiment of a medical device according to the present invention. [Diagram 35] FIG. 35 is a rear perspective view of the medical instrument of FIG. 34 with the plunger depressed. [Diagram 36] FIG. 35 is an end view of the medical device of FIG. 34. [Figure 37] FIG. 37 is a cross-sectional view taken along line BB in FIG. 36. [Figure 38] FIG. 37 is a cross-sectional view taken along line AA in FIG. 36. [Figure 39] FIG. 13 is a rear perspective view of an eighth embodiment of a medical device according to the present invention. [Diagram 40] FIG. 40 is a perspective cross-sectional view of the medical device of FIG. 39. [Diagram 41] FIG. 40 is a rear view of the medical device of FIG. 39. [Diagram 42] FIG. 42 is a side cross-sectional view taken along line AA in FIG. 41. [Diagram 43] FIG. 13 is a side view of a ninth embodiment of a medical device according to the present invention. [Diagram 44] FIG. 44 is a cross-sectional view taken along line AA in FIG. 43. [Diagram 45] FIG. 44 is a cross-sectional view taken along line AA in FIG. 43. [Figure 46] FIG. 46 is an enlarged view of the circled portion B in FIG. 45. [Figure 47] FIG. 44 is a rear perspective view of the medical device of FIG. 43. [Figure 48] FIG. 44 is a rear view of the medical device of FIG. 43. [Figure 49] FIG. 49 is a cross-sectional view taken along line AA in FIG. 48. [Figure 50] FIG. 49 is a cross-sectional view taken along line AA in FIG. 48. [Figure 51] FIG. 49 is a cross-sectional view taken along line AA in FIG. 48. [Figure 52] FIG. 15 is a perspective view of a tenth embodiment of a medical device according to the present invention. [Figure 53] FIG. 53 is a cross-sectional view of the medical device shown in FIG. 52. [Figure 54] FIG. 53 is a side cross-sectional view of the medical device of FIG. 52. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] 1, there is shown a medical instrument according to the present invention, generally designated by the reference numeral 10, used to aid in successful placement of a needle tip within a blood vessel. The medical instrument 10 comprises a body 11 housing a plunger 13 of circular cross section having raised abutment members, in this example ribs 15, spaced apart along its length thereby forming an abutment surface. The plunger 13 is disposed within a channel 17, also of circular cross section, within the body 11, and the plunger 13 is configured to move within the body 11 in a reciprocating back and forth motion in a direction substantially parallel to the longitudinal axis of the body.

[0032] The body 11 has an abutment arm lever 19 adjacent the opening 21. The lever 19 extends parallel to the longitudinal axis of the device 10 and has a projection 23 at its free end having a tip 25 narrower than the gap 27 between adjacent ribs 15 on the plunger 13. A bellows 29 is provided having a sleeve 31 which fits over the body 11, forming an airtight seal with an interference fit to secure the bellows 29 to the body 11.

[0033] Plunger 13 is mechanically attached to bellows 29 at plunger end 33, and plunger 13 and bellows 29 are biased away from body 11 by compression spring 35. Needle 37 having bore 39 is molded into the opposing end 41 of body 11, with needle bore 39 opening into interior channel 17 of body 11 that receives plunger 13.

[0034] A second lever 43 extending substantially parallel to the longitudinal axis of the device 10 is disposed adjacent the end 41 of the device 10. The lever 43 has a latching surface 45 that engages a complementary latching ridge 47 on the plunger 13. The second lever 43 extends beyond the outer diameter of the body 11 to form a finger tab 49 proximal to the needle 37. The lever 43 is connected to the body 11 at its base 51 with an opening 53 filled around the lever 43 by overmolding an elastomer within the opening 53. The elastomer bonds to the body 11 and the lever 43, thereby forming an airtight seal within the opening 53. At the same time, when the finger tab 49 is pulled substantially radially away from the body, the elastomer allows the lever 43 to bend away from the longitudinal axis of the body 11, thereby causing the latching surface 45 to disengage from the latching ridge 47.

[0035] During use, bellows 29 is compressed (as shown in FIGS. 1, 3, and 4), which compresses spring 35 and positions plunger 13 relative to body 11 so that latching surface 45 overlaps latching ridge 47 of plunger 13. Latching surface 45 drops into gap 55 between latching ridge 47 and one of the ribs 15 on plunger 13, thereby holding plunger 13 in place and holding bellows 29 and spring 35 in compression. The mating of latching ridge 47 and latching surface 45 provides positive tactile feedback that instrument 10 is primed and ready to apply a vacuum to the tip of the needle upon release of plunger 13.

[0036] The operator inserts needle 37 into the patient and lifts finger tab 49. Lifting finger tab 49 bends lever 43, disengaging latching surface 45 from latching ridge 47, releasing plunger 13 and applying a vacuum to the needle tip. As fluid enters needle 37 (once the needle tip is inserted into the vein), both bellows 29 and spring 35 expand, thereby moving plunger 13 and causing tip 25 of projection 23 of lever 19 to move over rib 15 on plunger 13, which provides vibration and tactile feedback that the operator can hear and feel.

[0037] It will be appreciated that the device 10 may be provided to the operator in a pre-compressed state such that once the needle has been inserted into the patient, the operator only has to release the lever 43, thereby ensuring a very simple sequence of operating steps.

[0038] Although a particular means for holding the bellows in compression is shown by holding the plunger in a retracted position, other means may be used, such as, but not limited to, squeezing the body 11 to hold the plunger 13 in place prior to inserting the needle. In fact, the plunger may be held in place by the user pressing the lever 19. When the user releases pressure on the lever 19, the plunger is released and a user keeping their finger in contact with the lever 19 will feel the plunger rib 15 move past the projection 23. In fact, there may be a separate portion (not shown) in the body 11 with an opening that is thin-walled or has an airtight membrane that prevents loss of vacuum in the bellows 29, so that the user can feel the plunger 13 through the thin wall or membrane as it moves within the body 11, thereby providing tactile feedback. This opening (if provided) may be provided in conjunction with the lever 19 or separate from the lever 19.

[0039] As previously described in other embodiments, depending on the strength of the vacuum required at the needle tip and the geometry of the bellows, a spring may not be required. As described in other embodiments below, the plunger may be formed as part of the bellows, thereby eliminating one part.

[0040] The advantage of molding the needle directly into the body is that it reduces the amount of air trapped within the device, thereby improving the sensitivity of the overall device. It also eliminates the need to manufacture the needle separately with a luer fitting and flashback chamber. However, if desired, the needle need not be molded directly into the body, but instead may be attached using a luer as described in other embodiments below.

[0041] The finger tab 49 moves perpendicular to the longitudinal axis of the needle to ensure that the needle is not inadvertently advanced or retracted during actuation. As described in an alternative embodiment, the use of multiple arms (i.e., protrusions 23) and complementary abutment members (i.e., ribs 15) can be used to increase the sensitivity of the device while utilizing the previously described methods for generating tactile feedback.

[0042] 9-14, there is shown an alternative embodiment of a medical instrument, generally designated by the reference numeral 60. The medical instrument 60 is of similar construction to the embodiment described with reference to FIGS. 1-8, and like parts have been given the same reference numerals as before. The medical instrument 60 differs from the medical instrument shown in FIGS. 1-8 in that the body 61 of the medical instrument 60 is shorter than the body 11 of the medical instrument 10, and the bellows 63 is wider but more compact in the longitudinal direction than the bellows 29 of the previous embodiment. The lever 43 is provided with a finger tab 65 to facilitate release of the lever during operation of the instrument. Additionally, whereas previously the rib 15 of the medical instrument 10 was located along the upper surface of the plunger for engagement with an abutment lever arm 19 also located along the upper surface of the plunger, in this embodiment the rib 15 is located on the underside of the plunger 13 for engagement with an abutment arm lever 19 also located on the underside of the body 61.

[0043] 15-19, there is shown a third embodiment of a medical device used to aid in successful placement of a needle tip within a blood vessel, generally designated 100, which includes a body 101 defining a vacuum chamber 103 therein. The body 101 has a port 105 for engaging a needle hub (not shown), which defines a fluid passageway 107 from the exterior of the body to the vacuum chamber 103 within the body.

[0044] The medical device is further provided with means 109 for generating audio / tactile feedback to a user, said means functioning from the vacuum within the vacuum chamber. The means 109 for generating audio / tactile feedback comprises an abutment arm 111 and a complementary dedicated abutment surface 113 operatively engaged by the abutment arm. The abutment surface 113 has a plurality of closely spaced ribs 115 disposed along its length and facing the abutment arm 111.

[0045] The medical device includes a plunger 117 incorporating a bellows 118 that can be depressed inwardly, toward the port 105, to evacuate air from the vacuum chamber through the fluid passage. Once the air has been evacuated from the vacuum chamber, a valve 119 is operated to close the fluid passage, thereby preventing air from flowing back into the vacuum chamber 103. When the valve is in the position shown in Figures 15 and 19, fluid may pass through the fluid passage, but when the valve is rotated approximately 90° about the pivot point 121 by operating the valve arm 123, an elliptical cam 124 is forced inwardly against the fluid passage 107, thereby sealing the fluid passage. When the valve is rotated to a position that seals the fluid passage, the plunger remains depressed as fluid cannot flow into the vacuum chamber.

[0046] In use, air is evacuated from the vacuum chamber by depressing the plunger 117 and then closing the valve 119. A needle (not shown, in the case of the Seldinger technique, or a sheathed needle in the case of the modified Seldinger technique) is connected to the port 105 of the medical device. The tip of the needle is then introduced into the patient, often using ultrasonic guidance. Once the tip of the needle is inside the patient, the valve 119 is actuated to reopen the fluid passageway 107. Because the needle is placed inside the muscle, no fluid enters the fluid passageway and the vacuum remains intact. The medical practitioner can then use ultrasonic guidance, if necessary, to guide the tip of the needle towards the vein. Once the tip of the needle has penetrated the wall of the vein and is inside the blood vessel, blood is allowed to move into the fluid passageway by the action of the vacuum in the vacuum chamber 103. The assembly is closed to the atmosphere, thus preventing the dangerous introduction of air into the bloodstream.

[0047] As blood enters the fluid chamber, the plunger and bellows, previously held in a contracted configuration by the vacuum in the vacuum chamber, begin to expand outwardly, away from port 105. This expansion occurs partly due to the elastic properties of the elastically deformable material that makes up bellows 118, and partly due to helical spring 125 (as shown most clearly in FIG. 16, with bellows 118 removed for clarity). While it is believed that either natural elasticity or a spring would be sufficient to provide this force, a combination of the two allows for more rapid and sensitive operation of the device. However, it will be appreciated that the use of a spring is not necessary. It will be appreciated that if a spring is used, the force of the spring will push the bellows beyond its fully contracted / compressed shape upon closing of the valve and priming of the device, not shown, thereby allowing a higher vacuum to be generated than would be possible by using the bellows alone. This is true for all of the embodiments using a combination of a bellows and a spring to generate a vacuum, as described below.

[0048] As blood enters the fluid chamber and is drawn inwardly by the vacuum in vacuum chamber 103, abutment surface 113 moves relative to abutment arm 111, causing abutment arm 111 to releasably engage at least one of ribs 115 on abutment surface 113. When the abutment arm contacts rib 115, audio / tactile feedback is generated. As more blood enters the fluid passageway and into the bellows, abutment arm 111 successively contacts spaced ribs along the length of the abutment surface, causing a series of clicks as the abutment surface moves relative to the abutment arm.

[0049] It will be appreciated that in the illustrated embodiment there are two abutment arms 111, one on each side of the abutment surface, and one set of ribs 115 on opposite sides of the abutment surface. More or less than two abutment arms can be provided if desired, and indeed more than one abutment arm can be provided on one or more sets of ribs. The two abutment arms and the two sets of ribs are offset relative to each other in a direction parallel to the longitudinal axis of the medical device. In this way, the abutment arms and associated ribs operate in alternating fashion when providing audio / tactile feedback. Preferably, the two sets of ribs are offset by half the distance between the apexes of a pair of adjacent ribs 115.

[0050] Various advantages of the embodiment will become apparent upon further consideration. For example, to ensure the first click of the abutment arm against the rib occurs as soon as possible, it is advantageous for the abutment arm to be angled to force movement as soon as possible in response to pressure changes within the bellows. In the embodiment shown in Figures 15-19, a layout is shown in which a spring 125 biases the plunger 117 against the end of the bellows 118. The plunger has ribbed surfaces 115 patterned along the length of the plunger that are opposed to one another and offset from one another by a half pitch along the length of the plunger.

[0051] The spring 125 overcomes the resistance of the abutment arms / ribs and ensures that the necessary vacuum is created. The spring increases the rate at which bellows 118 expands, imparting more expansion energy to the bellows, resulting in a higher vacuum, which causes fluid to flow into the needle and bellows faster, resulting in an earlier first click and subsequent clicks. The force generated by spring 125 (preferably) increases the vacuum force generated by the bellows beyond that required to overcome the friction of the abutment arms on the ribs. Thus, the combination of spring and bellows results in a more responsive device and speeds up the onset of haptic / audio feedback.

[0052] The expansion of the spring, and therefore the movement of the plunger and the generation of feedback, is constrained by the bellows, which is held by the vacuum. Thus, although the abutment arm is no longer on the bellows as in previous implementations, its movement is still directly controlled by the bellows. Importantly, the arrangement of spring 125 and plunger 117 limits / prevents the formation of a concave surface when the flat end of the bellows is pressed down to create a vacuum. This is advantageous because it eliminates the need for the ingress of fluid to first act on the concave surface to re-form the flatness of the outermost end of bellows 118 before the bellows begins to expand longitudinally. It also directs the expansion of bellows 118 along the longitudinal axis of the medical device, thus limiting the curvature of the bellows, which can be further supported by providing a mating feature between the bellows and plunger 117 to allow the plunger to be positioned on the bellows.

[0053] Advantageously, when plunger 117 is fully pushed into body 101, it hits a stop indicating the bellows is fully displaced to create maximum vacuum, and the stop provides feedback to the user that the bellows is fully compressed and the maximum amount of air has been expelled from the bellows before the valve closes to prime the device. This provides the operator with peace of mind that the device is primed, making the device easier to use and resulting in repeatable performance from the device. Releasing the force compressing the bellows causes the bellows to rebound, preferably curving the abutment arms against the ribs to prime the bellows for very small movements of the bellows with a small volume increase. In terms of the overall dimensions of the medical device, the configuration shown in Figures 15-19 allows bellows 118 to be manufactured with a very small internal volume / diameter, allowing a relatively long travel of the plunger for any given pressure / volume change caused by blood entering the needle. Additionally, the plunger reduces air pockets within the compressed bellows, effectively forming a plug and reducing the effective compressed internal volume of the bellows, thus making it more responsive to pressure changes.

[0054] Another advantageous aspect of the present invention is the way in which both the abutment arms and the abutment surfaces are located inside the bellows and the body of the device. Locating all these components internally advantageously reduces air pockets and provides a more ergonomic solution than an externally mounted spring. Locating the spring 125 and the means for generating audio / tactile feedback 109 internally eliminates the need for a bellows housing which adds thickness and weight to the device, allows for additional tactile feedback of the bellows moving in the operator's hand, and allows the operator to see directly inside the bellows. Advantageously, this embodiment allows for easy removal of the bellows from the valve for blood sampling. It will be appreciated that this feature of easy removal of the bellows is convenient, but not essential. Instead, the operator can simply compress the bellows once more to expel the blood sample from the device.

[0055] The movement of the loaded spring plunger 117 is controlled by the pressure in the bellows 118, and the spring 125 allows for a higher vacuum, a stronger rebound, and therefore a faster response after the blood vessel is punctured. The valve can be overmolded onto the body, reducing the number of assembly steps. The valve is preferably formed of a thermoplastic elastomer (TPE) that can be overmolded onto the body of the device, preferably made of clear grade polypropylene, high density polyethylene (HDPE), or medical grade silicone rubber with a Shore hardness of 10-55 Shore A. A thin plastic or metal clicker material can be used for the clicker (abutment arm), with a minimum Shore hardness of the plastic being preferably 60 Shore D. A similar Shore hardness is used for the plunger and abutment members (ribs), resulting in an audible click that must be heard even when immersed in blood.

[0056] The spring loaded plunger can contribute more to creating a vacuum in the bellows than the bellows itself, especially if the bellows is made of a soft material. In fact, the plunger can have a wall / sleeve that prevents deformation of the bellows walls when forced to expand by the force of the spring, ensuring that an adequate vacuum is created. This is particularly relevant if the bellows walls are unable to maintain their intended shape during expansion due to the high vacuum levels created by the spring.

[0057] Bellows with volumes in the range of 0.5ml to 2.5ml may have limited ability to press the abutment arms onto the abutment surface. Adding a spring can ensure that the abutment arms move over the abutment surface and capture the bellows.

[0058] Although ribs 115 are illustrated on plunger 117, it will be understood that ribs 115 may be formed in fluid passageway 107, and indeed ribs 115 may be formed with openings to facilitate molding (not shown) with abutment arms 111 located on plunger 117. Advantageously, the neck of bellows 118 covers these openings to maintain an airtight device.

[0059] 20-26, there is shown a fourth embodiment of a medical instrument in accordance with the present invention, generally designated by reference numeral 200, with like parts being given the same reference numerals as before. Medical instrument 200 differs from the previously described medical instruments in that it includes a twin-skin bellows 201 having an outer bellows skin 203 and an inner bellows skin 205. A plunger end cap 207 is connected to the outermost ends of each of the outer bellows skin 203 and the inner bellows skin 205. Plunger end cap 207 has an aperture 208 for passing an elongated shaft 209 therethrough.

[0060] 23 and 26 in particular, it can be seen that there is an abutment arm 211 on the plunger end cap 207 and an abutment surface 213 on the elongated shaft. The abutment surface is again provided by a plurality of closely spaced ribs 215. By closely, we mean less than 1.0 millimeter (0.001 m) apart. In some embodiments, the spaced ribs can be more than 1.0 millimeter (0.001 m) apart, but less than 4.0 mm (0.004 m) apart. In effect, there are again two abutment arms 211 and a pair of abutment surfaces 213, one for each abutment arm, each abutment surface 213 including a plurality of ribs along its length for engaging a complementary abutment arm 211.

[0061] In use, the end cap is depressed to expel air from bellows 201, causing elongated shaft 209 to pass through aperture 208 in plunger end cap 207. Once the air has been expelled, valve 119 operates (as shown in Figures 24 and 25) to close fluid passageway 107 and maintain the bellows in a collapsed state. A needle or sheathed needle is attached to port 106 and the needle tip is inserted into the patient before the valve is released again. Once the needle tip enters the vein, the vacuum force created by the natural elasticity of bellows 201 causes the bellows to expand and blood to be drawn into the bellows. As bellows 201 expands, plunger end cap 207 moves outward and abutment arms 211 move against ribs 215 of abutment surface 213, thereby providing audio / tactile feedback to the user indicating that the needle tip has been correctly positioned within the vein.

[0062] The structure shown in Figures 20-26 has several additional features and advantages. For example, a dual bellows is shown with an outer folded wall 203 and an inner folded wall 205, with a central ribbed shaft 209 attached to the base of the inner bellows. The ribbed shaft 209 passes through an aperture in a plunger end cap 207 that is provided with an abutment arm. The end cap is at the end of the bellows and moves with the bellows as it expands and contracts, providing tactile and audio feedback.

[0063] A double bellows with an outer diameter of 13 mm and an inner diameter of 6.4 mm can generate twice the expansion force with 75% less volume than a comparable single bellows with an outer diameter of 13 mm of the same material and wall thickness. This reduction in volume correlates to an increase in length along its axis with any increase in pressure within the bellows and a corresponding increase in change in length. Advantageously, due to the double wall, it can generate almost twice the vacuum of a standard single bellows with the same outer diameter. This arrangement allows for an in-line arrangement of the abutting arms and ribs, avoiding the risk of jamming between the ribs and arms impeding the movement of the bellows during expansion.

[0064] Central ribbed shaft 209 is attached to and extends outwardly beyond the base of the inner bellows 217. This base 217 of the inner bellows is forcefully inserted into the space formed by the cross 219 (best shown in FIG. 24) of valve connector 221, which forms a seal with the opening in bellows 201, such that when inserted into bellows 201, there is only a hole connecting the interior volume of the bellows to the valve housing fluid passage 107, and valve connector 221 has a push fit with the main valve body (this valve connector 221 component has been removed from FIGS. 21 and 22 for ease of viewing the remaining components).

[0065] Advantageously, central shaft 209 having ribs 215 connecting the base of the inner bellows to the base of the outer bellows ensures that the walls of the inner and outer bellows portions move in unison, providing greater expansion forces to the bellows and plunger end cap 207.

[0066] Of particular note is the abutment arm clicker located within the plunger end cap, with the two abutment arms spaced 1 / 2 pitch apart to allow for increased levels of sensitivity. The number of abutment arms can be increased with the pitch changed accordingly. This aspect of the invention is applicable to most, if not all, of the embodiments described herein.

[0067] Referring to the exploded view, an extension of the inner bellows extends through the main opening of the bellows and sits between the cross-shaped ribs of the neck portion. Ribbed shaft 209 is forcibly located on the opposite side of the extension from the open side, rigidly connecting valve connector 221, bellows 201 and ribbed shaft 209 together. Advantageously, the location of cross-shaped ribs 219 on valve connector 221 allows air to flow centrally through the central opening of the neck portion, between cross-shaped ribs 219 and into the interior volume of bellows 201.

[0068] It will be appreciated that this arrangement allows for an increase in the maximum potential vacuum that can be generated for a given outer diameter of the cylindrical bellows, reduces any air pockets during compression, improves the responsiveness of the system, and keeps the abutment arms and abutment surface ribs aligned along the central axis. This design also allows for hard stops for operator comfort. The dual bellows can also be made in multiple pieces for ease of manufacturing.

[0069] 27 to 31, there is shown a fifth embodiment of a medical instrument according to the present invention. It can be seen that the medical instrument comprises a substantially outer rectangular frame 301 for guiding a plunger 302 and a bellows 303. A pair of abutment arms 305 are attached to the plunger 302, and a pair of abutment surfaces 307, each having a plurality of ribs, are formed on the inner surface of the sides of the frame facing the abutment arms.

[0070] In use, the plunger is depressed, contracting the bellows and expelling air from the bellows. A needle is connected to port 105. If a valve (not shown) is provided, it is sealed to prevent premature expansion of the bellows. Alternatively, if no valve is provided, the user holds the plunger in place by keeping their thumb on the plunger. Alternatively, if a latch (not shown) is provided, it can be used to prevent premature expansion of the bellows. Once the needle tip is inside the body, the plunger may be released as it will not expand until the needle tip enters a blood vessel.

[0071] This embodiment has several advantages. It is a very simple embodiment with two parts (excluding the valve), with the abutment arm formed as part of the bellows (although it may be separate). In use, the bellows 303 is compressed and the valve is closed before the attached needle (not shown) enters the body (at this stage the valve is open). The integrated abutment arm has an opening that aligns with the arm of the frame, and the opposite surface presents a ribbed surface that slightly overlaps and engages the contact edge of the abutment arm. This arrangement allows the bellows to have a relatively small diameter, thus allowing a high level of movement for any volume change. As mentioned before, the spring can be applied internally or externally. It is envisaged that the opening of the bellows 303 needs to be large to facilitate the placement of the spring internally.

[0072] 32 and 33, there is shown a sixth embodiment of the present invention, generally designated by reference numeral 400, with like parts given the same reference numerals as before. Medical device 400 comprises a frame 401 having a port for attachment of a needle 403. Frame 401 has an opening into which the stem of bellows 407 fits loosely, the other end of the bellows being attached to the frame which fits tightly with the inner protrusion of the bellows. A spring 413 biases the frame from the bellows stem. The frame has a clasp 405 for engaging bellows 407 and holding the frame in place on the bellows stem with the bellows in a collapsed configuration. When use of the device is desired and the needle tip is placed inside the patient's body, clasp 405 can be released. As bellows 407 expands due to the additional force provided by the spring, frame 401 moves and an abutment arm on the frame moves along and against abutment surface 409 on the outer surface 411 of a portion of the bellows, clicking a rib 415 on abutment surface 409.

[0073] In this embodiment, no valve is required. The user releases the contraction force on the bellows when the needle is inserted into the patient, allowing the bellows to expand as the clasp is released, thus creating a vacuum within the bellows. The bellows protrusions that fit into the frame reduce air pockets within the bellows and improve sensitivity. The clasp 405 or abutment arm may be designed to break, limiting its use to a single-use device. The rib 415 and flange 417 to which the clasp is secured may be made from a separate, third piece that fits onto the bellows stem.

[0074] 34-38, there is shown a seventh embodiment of a medical device according to the present invention, generally designated by reference numeral 500, with like parts being given the same reference numerals as before. The seventh embodiment is similar in many respects in construction to the third embodiment (described above with reference to FIGS. 15-19). First, with reference to FIGS. 34 and 35, there is shown a medical device having a body 501, a plunger end cap 117, a valve 119 and a port 105. In FIG. 34, the device is at rest, the plunger end cap 117 is not depressed and the bellows (not shown) is not compressed. In FIG. 35, a user is pressing the plunger end cap 117 inwards with their thumb, thereby compressing the bellows. Once the bellows (not shown) is compressed and the air has been expelled from the bellows, the valve can be actuated to seal the fluid passageway 107. With particular reference to FIG. 35, when the plunger end cap 117 is depressed, the ribs 503 on the abutment surface can be seen. These ribs 503 engage with abutment discs 505 on the bellows.

[0075] With particular reference to FIG. 37, it can be seen that the valve 119 has an alternative cam surface. When the valve arm 123 is in the upright position as shown in FIG. 37, the fluid passageway 107 is blocked. When the valve arm is pivoted forward or backward about the pivot point 121 by the user manipulating the valve arm with a finger or thumb, the valve reopens the fluid passageway. It will be appreciated that, similar to the third embodiment shown in FIGS. 15-19 above, the valve arm can be positioned near the needle luer attached to the device. In this manner, the user can release the valve arm in a direction generally perpendicular to the longitudinal axis of the attached needle.

[0076] In use, as shown in FIG. 37, the plunger end cap is pushed inwardly into the body, placing the valve in a closed position (it will be appreciated that in this configuration, the bellows 103 is not folded and no air is evacuated, nor is the plunger end cap 117 pushed inwardly; only the valve is being operated). When the plunger is pushed inwardly to collapse the bellows, the valve is closed and the needle is placed at the end of the port 105. The needle is then introduced into the patient's body before the valve is released / opened. Once the needle tip (not shown) enters the blood vessel, the bellows 103 is free to expand again due to the elastic force of the elastically deformable material that forms the bellows. An abutment arm 505 attached to the outermost end of the bellows contacts a plurality of ribs 503 on the inner abutment surface of the body as the bellows 103 expands, generating audio and / or tactile feedback. Although shown as a separate part, the abutment arm may also be formed as part of the bellows 103.

[0077] 39-42, an eighth embodiment of the present invention is shown, generally designated by reference numeral 600, with like parts having the same reference numerals as before. The embodiment shown in FIGS. 39-42 differs from the other embodiments in that it is provided with a vacuum cylinder 601 that may be attached to the end of a body 603 to provide a vacuum source. The vacuum cylinder 601 is not a bellows and does not collapse. It is envisioned that the vacuum cylinder may be provided by a capsule that is evacuated and sealed. A needle 605 is connected to the body 603, although this is not required and a separate needle may be connected to the body 603. The body 603 further comprises an internal piston 607 housed within a cylindrical 609 casing. The piston 607 is configured to move in a direction parallel to the longitudinal axis of the body. The internal piston has an abutment surface 611 with a plurality of ribs arranged in a sawtooth configuration along its length for engaging an abutment arm (not shown) attached to the inside of the cylindrical casing 609. The body 603 further comprises a means for piercing the seal on the vacuum cylinder, provided via a hollow pipe 613 attached to the outer end of the cylindrical casing 609 and open at both ends, and having a sharp portion for piercing the seal of the vacuum cylinder.

[0078] In use, once the needle tip is inside the patient's body, the vacuum cylinder 601 is introduced into the end of the body 603 by piercing the vacuum cylinder 601 with a hollow pipe 613. The vacuum cylinder then creates a vacuum within the cylindrical casing 609, which draws the piston inwards. The piston is held in place until the needle tip enters a vein and the pressure at the needle tip is reduced. Blood begins to flow through the needle and into the cylindrical casing 609, drawing the internal piston back towards the vacuum cylinder 601 and generating audio and / or tactile feedback by the abutment surface engaging the abutment arm.

[0079] It will be appreciated that this embodiment has many differences and advantages over the previous embodiment. First, the vacuum is applied by a source other than a bellows. Second, the addition of a one-way valve (e.g., a duckbill valve) allows the vacuum source to be removed (not shown). The magnitude of the vacuum can be selected for different patient physiology and different tasks, depending on the level of vacuum the physician deems necessary, by providing different vacuum cylinders with different vacuum levels (measured in KPa) inside. This embodiment has the advantage of being very compact.

[0080] Manual vacuum generation using a syringe is also conceivable, allowing regeneration of the vacuum after a failed insertion, but a pre-filled vacuum vial is considered better. A push-on vial for introducing the vacuum penetrates the rubber seal. There is a very small amount of air on the other side of the piston, so the piston does not move much, and the amount of air is minimized by reducing any gap between the main housing and the plunger and ensuring that the audio / tactile feedback mechanism has the smallest possible air space within its enclosure. The piston flange is pressed, so it directly engages the abutment surface. Advantageously, a wiper is used to limit friction on the plunger, so that small pressure changes are registered as "clicks". Advantageously, the inner diameter of the main housing is made as small as possible to reduce the contact area between the wiper and the inner wall, further minimizing friction. A smaller diameter body results in a higher vacuum being created compared to a larger volume of the vacuum chamber. Although only one row of ribs is shown, it will be understood that, as previously mentioned, the number of abutment arms can be increased and more than one row used to increase the number of clicks for any given movement of the piston.

[0081] Although an abutment arm has been described to generate feedback, it will be appreciated that a plug can be inserted between the valve and the vacuum chamber. In this embodiment, the plug maintains a seal between the air volume on the valve side and the vacuum chamber. When the vacuum is applied, there is preferably a small amount of air on the valve side of the plug, which causes the applied vacuum to apply pressure to the plug, which is releasably held to its seat by the retaining means within a predetermined pressure difference on either side of the plug. As before, there is minimal air on the needle side of the valve to ensure that the plug is not released before fluid has entered the needle. Once the valve opens and fluid has entered the needle, additional pressure generated on the valve side of the plug releases the plug, which (due to the pressure difference) rapidly ejects from its seat and makes a clicking contact with a surface, thereby generating a sound, indicating that blood has entered the needle. The plug can be a metal bearing and the contact surface can be another metal surface which generates a distinctive and very audible sound. It will be appreciated that the movement of the plug on release can generate a clicking sound, as previously described.

[0082] While the vacuum is described above as being introduced from the vial by piercing a rubber seal, it will be appreciated that the vacuum can alternatively be applied by opening a valve between the vial and the port to create a vacuum at the port (as described in the previous embodiment).

[0083] 43-51, there is shown a ninth embodiment of the invention, generally designated by reference numeral 700, with like parts given the same reference numerals as before. This is a very simple implementation, low cost to manufacture and easy to use. The device 700 comprises a port 105 for attachment of a needle (not shown), a bellows 103 which can be compressed, and a spring 125 to assist in the expansion of the bellows. No valve is provided, but one may be provided if desired. An abutment arm 129 is attached to the inside of the bellows recess 131, and a ribbed abutment surface 130 is formed on the bellows 104. Depressing the plunger 117 compresses the inner bellows 104 and expels air.

[0084] The embodiment shown in Figures 43-51 includes an integrated bellows and rib configuration. There is a very small air pocket and it can be molded in one piece. In use, the user compresses the bellows to create a vacuum. The user maintains the bellows in a compressed state by squeezing the outer annular surface 126 that holds the cylindrical shaft 127 within the bellows recess 131. Upon inserting a needle (not shown) attached to the port of the instrument, the user releases the grip on surface 126, which releases shaft 127, thus applying a vacuum within the bellows as it expands again, which in turn applies a vacuum to port 105. The instrument can have a valve adjacent to the port that operates in a similar manner to the previous embodiment. The advantage of this solution is that the user feels the movement of abutment arms 129 against ribs 130 while the bellows expands.

[0085] The drawing shows only one abutment arm 129 extending over a rib 130 within the body of the device. The abutment arm may be an annular ring and the rib may be formed circumferentially inside the body. Alternatively, the abutment surface rib, abutment arm and spring may be added after molding through an opening (not shown) in the end of the cylindrical shaft 127 that sits within the bellows recess 131.

[0086] The cylindrical shaft 127 located within the bellows recess 131 functions to fill the voids within the bellows when it is compressed. The diameter of the cylindrical shaft 127 and the bellows recess 131 is close to the folded inner diameter of the body (i.e., the bellows chamber), advantageously making the diameter narrower. In this way, the air in the folded bellows is significantly reduced because the ribs receive the central components when the bellows is folded. As a further alternative, the ribs can be located on a sleeve located in the narrower part of the bellows body and the abutment arms can be located on an insert, as shown in the drawings. Additional vacuum / responsiveness can be provided by a spring, if desired.

[0087] 52-54, there is shown a tenth embodiment of the present invention generally designated by reference numeral 800, with like parts being given the same reference numerals as before. The device comprises a body 801 similar to a standard syringe, with a plunger 803. The syringe is preferably a so-called "frictionless" syringe as is known in the art. A spring 805 is operable to bias the plunger outwardly, thereby drawing fluid into a syringe chamber 807 and creating a vacuum inside the syringe chamber 807. A collar 809 has an abutment arm 811 thereon for engaging an abutment surface 813 along the shaft 815 of the plunger 803.

[0088] A valve (not shown) can be added to the port or release latch that controls the position of the plunger 803 within the body 801. In use, the user depresses the plunger 803, closing the valve (not shown) and positioning the plunger 803 so that there is minimal air in the chamber 807 between the plunger and the port 817, thereby keeping the spring 805 in compression. The user inserts a needle (not shown) attached to the device into the patient's body, opening the valve and applying pressure to the port. As the needle penetrates the vein, the spring extends the plunger, causing the abutment surface 813 on the plunger to pass the abutment arm 811, making a clicking noise as it moves. While the use of this embodiment has been described using a valve, a latch can also be deployed that automatically holds the plunger in a fully depressed position, and is released by the operator once the needle is inserted into the patient.

[0089] There are several additional advantageous aspects of different embodiments of the present invention, which are outlined below.

[0090] The device is very light and does not prevent the operator from delicately manipulating the needle. Importantly, the actuation of the valve or latch allows the needle tip to be vacuumed but does not cause unintended movement of the needle tip that could cause the operator to damage or miss a vessel. The third embodiment described above requires the valve to be rotated with a force perpendicular to the needle, thus preventing forward and backward movement of the needle. Due to the fact that the needle is located inside the patient when the valve is open, the needle can only move forward or backward. The general nature of silicone valves is that they require very little force to open, regardless of the lever position. Similarly, in embodiments with a latch configuration, the actuation of the latch does not adversely affect the placement of the needle in the patient.

[0091] The design of the end of the instrument adjacent the needle with the valve lever does not interfere with a standard grip used by the operator. Although a light touch squeeze valve has been described, other types of valves may be used as will be understood by those skilled in the art. Importantly, the valve / latch is adjacent to where the operator holds the needle and is very easily accessible and actuated by gentle movements of the operator's fingers.

[0092] Operators have developed fine motor skills and techniques / grips for directing needles into small blood vessels over the years, and the purpose of the present invention does not require the operator to deviate from this. Thus, the instrument must be lightweight and operable with currently deployed grips and movements. The means for deploying a vacuum at the needle tip must be proximal to the needle grip, easily found, and should require minimal movement and force to operate. Importantly, in the illustrated embodiment, moving the lever backwards does not encourage further needle advancement into the vessel, with the risk of penetrating the vessel completely as a result. The operator does not need to change or release the grip on the needle to release the valve, which is simply released with a normal grip on the needle or the instrument itself.

[0093] As mentioned above, it is important that the device does not require any changes in the way the user holds the needle. This is a learned method and cannot be compromised, nor is it acceptable to stop mid-insertion to open the valve. The valve needs to be lightweight and the valve lever needs to be easily found, so it should be close to the operator's fingertips, and its contact point should be as forward as possible towards the needle. Preferably, the action required to open the valve should not move the needle back and forth, and the valve should provide positive feedback in the open and closed positions. The release of the valve needs to be positive so that the user can be confident that the device is primed and active. The valve can be of any type, including a stopcock, but in particular its release should not cause the operator to change his grip on the needle or apply a force, directly or indirectly, to the needle, resulting in an unintended change in the needle's position or trajectory relative to the vessel, causing undesirable consequences.

[0094] Preferably the valve is provided by lightly pinching a silicone tube with a lever, requiring only a light touch to unpin the tube and allow first air and then blood to flow into the bellows.

[0095] The repulsive energy of the bellows can also be increased by applying an external vacuum with the bellows / vacuum chamber placed within a larger bellows / vacuum chamber. Other variations can be made without departing from the invention. Although dual bellows and springs have been shown in various embodiments, it will be understood that their use to increase the vacuum and repulsive energy of the bellows, thereby improving sensitivity, may be used interchangeably in one or more other embodiments. In fact, springs may also be used with dual bellows if it is necessary to create a very high vacuum, highly sensitive version of the instrument.

[0096] The pitch of the abutment surface relative to the pitch of the abutment arms may be important. There may be value in increasing the pitch of the ribs and increasing the number of abutment arms that do not click simultaneously on a rib. There are multiple rows of ribs on the body, each row with its own abutment arm, and each row or pair of abutment arms are arranged so that there are no simultaneous clicks from each row / clicker pair while the bellows is expanding. Reducing the pitch of the ribs and arms improves resolution and increases the likelihood that the ribs are at the cusp of a click when the valve or bellows is released, resulting in a faster first click indicating the vein has been punctured. A bellows of the smallest diameter practical to accommodate the means for generating tactile / audio feedback is preferred.

[0097] The design of the abutment arm is such that it needs to click quickly, especially on the first click. Therefore, it cannot be too long. It also cannot be too hard (due to a combination of material and thickness) or it may increase friction and restrict the movement of the bellows, delaying the first click. In some embodiments, the abutment arm can be constructed from rubber, such as rubber having a Shore A hardness of about 40A to 80A. This has been shown to provide a good level of audio feedback and be flexible enough to limit friction of the expanding bellows. As previously mentioned, the abutment arm can be made of a thin plastic, metal, or elastomer. In the embodiment shown in Figures 1-14, it is envisioned that the material of the arms and ribs can be a relatively hard polymer, such as acrylonitrile butadiene styrene (ABS), with a typical Shore hardness of over 60 Shore D.

[0098] Different combinations of materials for the arms and ribs can produce different acoustic effects. For a rubber arm to strike a plastic rib and produce a low pitch that is audible, a relatively large contact area between the two (defined by the area of ​​the rib impacting the rib) and a relatively stiff arm to produce a loud enough sound to be heard through the bellows and felt by the operator is required; this relatively large contact area and stiff arm adds resistance that must be overcome by the spring and / or bellows, which can make it difficult for some users to depress the plunger and slow the device's response to pressure changes. The same is true for a hard plastic or metal arm, which can produce an audible sound even with a small contact area, but this combination still produces a relatively high friction that must usually be overcome using a spring.

[0099] Advantageously, the arm can be a combination of rigid and flexible materials, with the base being the more flexible material, or it can be made entirely of rigid material and fixed to a flexible base, allowing it to bend relatively easily and reducing resistance to movement, as previously described. The configurations of the first and second embodiments differ in that they deploy a longer lever to generate audio and tactile feedback. It has been found that using an ABS polymer lever and plunger with a minimum Shore hardness of 60D provides the necessary tactile and audio feedback even when submerged in blood.

[0100] Through experimentation, it was found that by making the ribs approximately 1mm pitch, once the arm leaves the previous rib, it picks up enough speed to produce an audible sound when it hits the next rib. Reducing this pitch to less than 1mm reduces the kinetic energy of the arm, reducing the impact force and the sound produced from the impact.

[0101] It will also be appreciated that the effective amount of striking surface area between the rib and the arm can be altered by adding a radius or chamfer to the impacted corners of the square rib to increase the audible volume of the impact making the click more audible. It will also be appreciated that the pitch and height of the rib can be altered to provide different sounds indicative of various stages of expansion and contraction of the bellows as the arm moves relative to the rib. For example, there may be a larger gap between the first rib and the next rib that is impacted upon release of the latch or valve, with the first click indicating that the device is primed and the second click indicating that blood has entered the needle. This larger gap allows the bellows to expand when the compressive force is released before blood enters the needle. The larger gap also indicates that the bellows is fully collapsed. The pitch and amplitude can also be altered to indicate that the bellows is fully collapsed. This ensures that the maximum vacuum is achieved within the bellows and sufficient travel to provide the sensitivity of the device.

[0102] It will be appreciated that the arms can be hinged to provide different resistances in different directions and therefore different sounds. Indeed, torsion springs can be usefully positioned to achieve this, providing very high levels of kinetic energy on the release of a hard material object (or the spring may be locally hardened) on the striking end from the rib to generate an audible striking sound on the rib, with the spring providing different resistances depending on the direction in which it bends. Torsion springs can also be used to control stiffer ribs. Of course, other types of springs can also be used, such as coil springs at the base of a stiff rib, or legs of coil springs acting as arms. In all cases, the coil springs provide the flexibility required to generate the kinetic energy required for the rib while minimizing friction.

[0103] While the bellows is generally shown as being in line with the needle, it will be appreciated that the bellows may be at an angle of up to 90 degrees to the needle, effectively shortening the overall length of the device and allowing the operator to easily hold the device between their thumb and fingers. This effective shortening of the device significantly reduces the likelihood of the device contacting the palm of the operator's hand, particularly when the bellows is extended, and eliminates the need for the operator to change their well-established precision motor grip, which is important for carefully guiding the needle during operation, which is particularly important for operators with smaller hands. This provides a significant advantage over using a conventional syringe, which requires the operator to change their grip and where the typical syringe used is longer than the device.

[0104] It has been found that in some embodiments, fluid entering the bellows flows over the rib and arm configurations, even submerging them. It will be appreciated that providing a fluid passage opening or channel in the plunger can minimize this damping effect by encouraging the initial fluid to move away from the arms and ribs as it contacts the plunger and fills the bellows, thereby ensuring that the clicks are as loud as possible, especially the first few clicks before the bellows fills with liquid. Alternatively, a low friction seal can be added to the free end of the plunger, which moves with the plunger in the fluid channel and prevents blood from entering the first rib when it is impacted by the arms, further limiting the acoustic damping of the blood. To delay contact of the fluid with the arms and ribs, the ribs and arms can be positioned so that they are at their highest points and away from the initial fluid entry into the bellows.

[0105] Although the arms have been described as rubbing against the ribs to provide audio and audible feedback, it will be appreciated that any rubbing caused by the bellows moving in response to a drop in vacuum or blood ingress can provide audio / tactile feedback. Advantageously, the ribs provide a low friction solution that maximizes the force available within the bellows to generate vacuum, and also provide very effective audio feedback. It will be appreciated that although the bellows is shown to be cylindrical in shape, its shape may vary, and in fact may have a square or rectangular cross section. Air pockets between the needle and the bellows should be minimized where possible, and it is desirable for the diameter of any hole connecting the needle and the bellows to be less than the diameter of the largest needle expected to be used in the device, or as large as is practical for manufacturing.

[0106] Although the bellows has been described as creating a vacuum by the rigidity of its walls, it will be understood that a vacuum can be created by applying an expansion force using a spring or other means to expand its volume. A double bellows may be provided with helical folds to allow the inner core to be released from the mold. Expansion of a bellows with such helical pattern folds can result in rotation and elongation along its axis. The bellows is preferably blow molded, but may also be compression molded or rotationally molded. If the bellows opening is large enough relative to its diameter, and if the material has a high elastic limit, the bellows may be injection molded.

[0107] Preferably, it is desirable to have a small volume for the bellows to achieve the largest possible dimensional change of the bellows for a given volume change and reduce the weight of the device. The device should be able to draw enough blood into the transparent / opaque channel immediately after the needle that the operator can see to visually confirm that the needle is in the proper position, providing further assurance. The vacuum required to draw the blood depends, at least in part, on the gauge of the needle, which can be accommodated accordingly. In some embodiments, a trigger mechanism may be provided where the bellows moves against or contacts the user's hand (palm), which may also be used as an indication that the needle has successfully punctured the blood vessel.

[0108] It will be appreciated that the movement of the plunger can be converted into an electric charge to power an audio or light source to alert the operator of the extension of the bellows. For example, the abutment arm can be a piezo strip that generates a voltage during flexion, which can be used, for example, to light an LED or power a buzzer or other sensor or indicator to further alert the operator of the bellows movement.

[0109] Unless otherwise stated, the springs may be applied internally or externally to any embodiment. In many cases, the abutment arms are shown separate from the bellows, but it will be understood that the abutment arms may be part of the bellows. Indeed, if part of the bellows, the abutment arms are preferably located at the free ends of the bellows, but may be located anywhere in the moving portion of the bellows as desired.

[0110] It has been determined that the bellows must be capable of generating sufficient vacuum in the range of 150 mmHg (20 kPa) to 250 mmHg (33.3 kPa) at the tip of a needle, preferably in the range of 16 to 22 gauge, and having a length of 3 cm (0.03 m) to 8 cm (0.08 m). When the needle is connected to the bellows and the bellows is fully compressed and blood is drawn up through the needle, there must be a minimal amount of air in the chamber when fully compressed to avoid a pressure build-up, causing a reduction in volume (per Boyle's Law) and providing sufficient dimensional change to allow for the generation of audio and / or tactile and / or visual feedback as blood flows into the device.

[0111] Using a spring having a rate of 1635 Nm, the third embodiment provides a vacuum of 180 mmHg and has been found to provide a rapid response using a variety of needles.

[0112] It is important that the needle tip is evacuated before entering the blood vessel so that upon entry into the blood vessel the vacuum in the bellows chamber is released, which is registered as a change in the bellows dimension, resulting in a click or other positive audio and / or tactile feedback. For example, the abutment arm at the end of the bellows is tensioned against a rib to ensure that the first significant click occurs as soon as possible. It is not necessary that blood travel along the entire length of the needle, but that a registerable pressure change occurs in the bellows while it travels through the needle. In fact, the first click preferably occurs sooner than blood would passively exit the needle if the needle were not connected to the instrument, as this provides more immediate feedback to the operator than the traditional visual "flashback" method, which requires the operator to look away from the ultrasound screen to utilize this traditional cue.

[0113] To maximize the sensitivity of the device, the design must translate the smallest pressure increase in the system into a bellows movement to provide the critical initial click. To enable this, the bellows must have a chamber volume (when the bellows is compressed and a vacuum is created) such that the small amount of blood in the needle can be translated into a measurable dimensional change and a tactile / audio signal can be generated by the abutment arm. The bellows must be able to generate the necessary vacuum while being depressed to draw blood into the needle as quickly as possible in order to cause this dimensional change in the bellows as quickly as possible.

[0114] Thus, a bellows design is required that can provide the necessary vacuum at the tip of a commonly used needle, so that the bellows can draw blood through the needle, and the blood in the needle causes an appropriate dimensional change in the bellows, resulting in an increase in pressure, which in turn causes audio / tactile feedback more quickly than a flashback would normally provide. It will be appreciated that, although this preferably occurs sooner than the flashback, even if an auditory click is heard at approximately the same time that a flashback is observed, the auditory feedback does not require the operator to take their attention away from the needle tip, ultimately providing faster feedback and not distracting the operator from viewing the screen, thus eliminating the risk of the operator moving the needle too far or off target.

[0115] By approximation, it has been found that a 5 cm long 16 gauge needle, introducing 0.1 ml of fluid into a cylindrical bellows with an internal compressed diameter of 5 mm and a compressed volume of 1.26 ml, will provide a displacement of the order of 1.3 mm, with no air pockets present upon compression, which is sufficient movement to provide audio feedback in the described embodiment (where the ribs are spaced at a pitch at least less than the displacement). Bearing in mind that the bellows increases the blood flow rate through the needle, this improves the time it takes for the operator to receive notification that the needle is correctly placed, compared to traditional passive flashback methods. A smaller bellows volume provides proportionally more movement, which allows for better resolution and is even better in terms of speed of notification to the operator. Since the operator may wish to sample blood using the instrument, it may be desirable to have a larger uncompressed bellows volume of approximately 2.5 ml.

[0116] The device also allows collection of blood for analysis, in at least some embodiments, through a bellows that is detachable from the body of the device if desired, or blood can be squeezed out of the device by compressing the bellows, an extended use of which may require the addition of an anticoagulant. Although the abutment arms have been described as moving over fine pitch ribs, it will be appreciated that they may move over rough surfaces or ridges, or through a tortuous path (where the abutment arms are provided by protuberances or ridges), which will provide suitable tactile feedback. Although the bellows have generally been described as moving the clicker / abutment arms directly against the ribs or rough surfaces, it will be appreciated that the ribs or rough surfaces may move directly along the ribs. Indeed, the ribs / rough surfaces may move indirectly on the clicker / abutment arms that are connected to or may be part of the bellows.

[0117] As mentioned above, when fluid flows into the device, it is important that the corresponding reduced pressure level in the system translates into maximum dimensional change in the bellows. Therefore, any deformation of the bellows when physically depressed that does not directly translate to a vacuum in the bellows and audio / tactile / visual feedback upon recovery should preferably be avoided or minimized. Bellows made from low density polyethylene (LDPE), polypropylene, Hytrel®, thermoplastic elastomers, or other thermoplastics have wall thicknesses typically in the range of 0.1-0.3 mm and are easily deformable, or are made from softer silicone or TPE materials that are easily deformable. If air pockets are present in the fully depressed portion of the bellows, they will further slow and reduce the movement of the bellows, which may cause the user to question the value of using the device. For example, based on the previous example, if the depression caused by the concave end was 1 mm, and 0.1 ml of fluid was put into the system, even if the movement was only 1.3 mm, the recovery of this depression would severely affect the movement of the bellows (which is understood to be approximately equal to twice the volume of a 16 gauge needle that is 5 cm long). It would be desirable to provide the operator with a means to prevent such deformation, which may include a second non-deforming surface that engages with the bellows to avoid said deformation. Preferably, the bellows is attached to said surface to ensure that deformation of the bellows occurs only at the grooved wall and nowhere else.

[0118] The bellows are flexible and due to the fact that they curve when extended (the ends are not parallel) the bellows do not extend along their axis and therefore the extension is not uniform. Providing a guiding means ensures that the movement of the bellows is maximized for any drop in vacuum. This guiding means is preferably provided by a spring that directs the bellows in a particular direction as other guiding means may introduce friction into the system. Providing a spring also promotes uniform expansion of the bellows along the length required by the abutting arm / rib arrangement as described in the above embodiment.

[0119] However, it may be preferable to encourage the bellows to bend and extend more on one side. By restricting the movement ability of one side of the bellows, further movement of the free side is encouraged, creating a larger displacement that can be translated into feedback for a given vacuum drop. In this way, the first click for a given amount of fluid entering the device can be made sooner. Advantageously, once it is confirmed that the needle is in place, the restricted side may be released by the operator to allow the bellows to fully extend, or the restricted side of the bellows may be released automatically as the angle of the bellows changes as it extends. Referring to the third embodiment described above, the ribs may have different heights, thus releasing more easily on one side and allowing relatively more movement on the other side, thereby improving resolution. The ribs on the freer side may be positioned to maintain contact with the abutment arm as the bellows bends.

[0120] As mentioned above, air pockets in a bellows that is fully depressed before the valve is closed will cause a delay in the expansion of the bellows and therefore the initial "click" of the audio and / or haptic feedback. This is because the increase in pressure will compress the air (P1V1=P2V2) and cause the bellows to contract (you want the bellows to expand as quickly as possible). To reduce air pockets, one or more of the following techniques can be used:

[0121] First, the ends (unfolded walls) of the cylindrical bellows are preferably approximately parallel to each other so that when folded they touch or are as close to each other as possible. Second, a thin bellows material is used that allows maximum compression of the bellows folds. In this way, the stacked height of the wall folds is minimized, thereby reducing the dead space between the stacked walls. Third, it is considered useful to eliminate the void between the stacked bellows walls, either by filling that volume with a protrusion on the bellows itself, or by a separate part that can include a means for connecting directly to the valve or needle. Fourth, with the double bellows described above, the protrusion described above is in effect a second inner bellows incorporated into the first outer bellows. Fifth, the fluid channel between the main bellows chamber and the valve can be partially filled to reduce the air volume, leaving enough space to allow fluid and air to pass, but limiting air pockets. Sixth, partial filling of the fluid channel between the valve and the opening in the needle hub where blood enters the device can be applied. All or some of these techniques can be used to reduce the size of the air pockets in the bellows.

[0122] The volume of the fluid passage between the needle hub opening and the valve closing point is expected to be less than 0.05 ml, and preferably less (0.02 ml in the actual design). When the valve opens, a predetermined number of clicks occur before the needle contacts the fluid, allowing the air in the needle and the needle side of the valve to affect the vacuum drop in the bellows, thus making the operator aware of the operation of the device. It may be preferable to space the abutment arm and abutment surface so that there is no initial click when the valve opens before entering the blood vessel, eliminating false positives.

[0123] It is envisioned that various embodiments may be used to generate haptic feedback. First, the configuration for haptic feedback may be applied to the outer diameter of a cylindrical bellows. The bellows has a disk formed or attached thereto, preferably a thin material in the range of 0.1 mm (0.0001 m) to 1 mm (0.001 m) thick that can be flicked over the ribs. The ribs are positioned in close proximity to the outer surface of the bellows so that as the bellows expands, the disk flicks over the rib surface, thereby providing feedback. Multiple rows of ribs may also be provided. If multiple rows of ribs are provided, they are preferably spaced evenly around the bellows to reduce the tendency of the bellows to bend and reduce the chance of being pushed in during expansion, as this may cause the device to stop drawing blood into the bellows and stop providing haptic feedback.

[0124] When the spring is deployed, audio and / or tactile feedback may be generated by movement of any portion of the spring relative to an abutment arm or other protrusion.

[0125] In the described embodiments, reference is made to an abutment arm or an abutment disk that engages the abutment surface. It will be understood that the abutment arm can be a separate, separate arm or multiple separate, separate arms, the arm may be an elongated arm, or the abutment arm can take the form of a disk, a projection, a plate, a collar or annular ring attached to one of the body, a vacuum chamber, or a bellows (if present). The disk, plate, collar, or annular ring may have a uniform circumference or may have one or more circumferentially spaced protruding tabs for engaging the abutment surface. The abutment arm may be roughened.

[0126] Secondly, the placement of the haptic feedback can be applied along the longitudinal axis of the medical device. In this way, the bellows pushes the ribbed shaft onto the flicker (or vice versa), and the ribbed shaft is preferably aligned with the longitudinal axis of the bellows. It will be appreciated that where the clicker / rib contacts the fluid as it enters the bellows, the clicker / rib is in a position such that the fluid can pass without affecting their function. However, preferably, the clicker / rib is positioned such that the fluid does not pass over the clicker / rib during its entry into the bellows (when the device is held in the intended orientation), and the clicker / rib is not positioned where the fluid first collects within the bellows, and therefore does not interfere with the ability of the clicker / rib to generate the important initial click. The position of the abutment arms / ribs is such that the vibrations caused by their engagement are felt by the operator through the various housings. It is envisioned that if the abutment arms / clicker and abutment surfaces / ribs combination is inside the bellows, the sound waves will dwell longer, thus providing a longer feedback signal to the operator.

[0127] Priming the device after entry into the body but before entry into the blood vessel can be accomplished in a number of ways: first, by applying a vacuum in the bellows to the needle tip by opening a valve, second, by physically releasing the contraction force on the bellows or spring, which allows the bellows or spring to expand under its own force and apply a vacuum to the needle tip, and third, by applying an extension force to the contracted bellows, either separately or in combination with the first and second methods described above.

[0128] A one-way valve can be attached to the bellows to allow air to escape if the user accidentally presses the bellows while the needle is in the patient. It will be appreciated that in all of the described embodiments, the device prevents the drawing of air into the patient's bloodstream (air embolism), a potentially fatal complication that can occur when a needle or catheter-over-needle device is used for initial central venous puncture.

[0129] Although the invention is described from the perspective of an operator using ultrasound guidance, it will be appreciated that the invention may also be used to locate veins, typically without the use of ultrasound, in a typical clinical setting, for example, to locate blood vessels. Additionally, the instrument may be applied to many alternative procedures, such as, but not limited to, biopsy, fine needle aspiration, bone marrow aspiration, and placement of chest or peritoneal drains via the Seldinger technique, among others.

[0130] As used herein, the term elastically deformable will be understood to mean the property of a material, once deformed from its natural shape, to return to its original shape when the force is removed.

[0131] In this specification, the terms "comprise", "comprises", "comprised" and "comprising" are to be regarded as fully interchangeable and should be given the broadest possible interpretation.

[0132] The invention is not limited to the embodiments described above, but it may be modified in both structure and detail within the scope of the appended claims.

Claims

1. A medical device (10, 100) used to assist in successful placement of a needle tip within a blood vessel, comprising: The medical device comprises: a body (11, 101) defining a vacuum chamber (103) therein, said body having a port (41, 105) for engaging a needle hub, said port defining a fluid passageway from outside said body to said vacuum chamber within said body; means for generating at least one of audio and tactile feedback to a user affected by the vacuum in the vacuum chamber; Equipped with said means for generating feedback includes an abutment arm (19, 111) and a complementary dedicated abutment surface (113) operatively engaged by said abutment arm; the abutment surface having a plurality of closely spaced abutment members (15, 115) disposed along its length and facing the abutment arms; The medical device (10, 100) is operable to cause the vacuum in the vacuum chamber to move one of the abutment arm and the abutment surface relative to the other of the abutment arm and the abutment surface, thereby causing the abutment arm (19, 111) to releasably engage at least one of the abutment members (15, 115) of the abutment surface and generating the feedback.

2. 2. The medical device (10, 100) of claim 1, wherein the abutment arm (19, 111) and the abutment surface (113) are disposed inside the body.

3. 3. The medical device (10, 100) of claim 1 or 2, wherein the fluid passageway intermediate the exterior of the body and the vacuum chamber is provided with a valve (119) operable to selectively apply the vacuum to the port.

4. 3. The medical device (10, 100) of claim 1 or 2, wherein a releasable latch (43) is provided operable to control the application of the vacuum to the port.

5. 3. The medical device (10, 100) of claim 1 or 2, wherein the vacuum chamber comprises an elongated, collapsible bellows (29, 118).

6. 6. The medical device (10, 100) of claim 5, wherein the collapsible bellows (29, 118) is constructed from an elastically deformable material.

7. 6. The medical device (10, 100) of claim 5, further comprising a spring (35, 125) operable to expand the collapsible bellows.

8. 6. The medical device (10, 100) of claim 5, wherein the bellows (29, 118) has a pair of substantially planar, opposing end plates.

9. 6. The medical device (10, 100) of claim 5, wherein the bellows (29, 118) is provided with an internal plug operable to substantially fill a void within the bellows and minimize the amount of air inside the bellows when the bellows is in a collapsed configuration.

10. 6. The medical device (10, 100) of claim 5, wherein a guide means is provided for the bellows (29, 118) to control the direction of movement of the outermost end of the bellows, and thus the shape of the bellows, as the bellows transitions to or from an expanded configuration and to or from a contracted configuration.

11. 6. The medical device (10, 100) of claim 5, wherein the bellows (29, 118) has a dual skin of an inner bellows and an outer bellows.

12. The medical device (10, 100) of claim 5, wherein the bellows (29, 118) is substantially cylindrical.

13. 3. The medical device (10, 100) of claim 1 or 2, wherein the vacuum chamber comprises a releasably removable vacuum chamber.

14. 3. The medical device (10, 100) according to claim 1 or 2, wherein a plurality of abutment arms (19, 111) are provided.

15. 15. The medical device (10, 100) of claim 14, wherein a plurality of complementary abutment surfaces (113) are provided.

16. 16. Medical device (10, 100) according to claim 15, wherein each abutment arm (19, 111) is provided with a dedicated abutment surface (113).

17. 4. The medical device (10, 100) of claim 3, wherein the valve is actuated by applying a force perpendicular to the longitudinal axis of a needle connected to the body.

18. 5. The medical device (10, 100) of claim 4, wherein the releasable latch is actuated by applying a force perpendicular to a longitudinal axis of a needle connected to the body.

19. 4. The medical device (10, 100) of claim 3, wherein the fluid passage is defined by a portion of the body constructed from silicone rubber to which the valve engages.

20. The medical device (10, 100) of claim 1 or 2, wherein the vacuum is between 150 mmHg (20 kPa) and 250 mmHg (33.3 kPa).

21. A medical device (10, 100) as described in claim 1 or 2, wherein the valve has a Shore hardness of 10 to 55 Shore A.

22. 3. The medical device (10, 100) of claim 1 or 2, wherein the volume of the fluid passage between the needle hub opening and the valve closing point is 0.05 ml or less.

23. 3. The medical device (10, 100) of claim 1 or 2, wherein the port has a side port branching therefrom, the side port having a closure thereon.

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