VERTICAL CANNULA
Field of the Invention
[0001] The present invention relates to cannula devices for transcutaneous movement of fluid. In particular, the present invention discloses an improved form of cannula device.
Background of the Invention
[0002] The use of cannula devices in medical procedures is extremely common especially where fluid is injected into or removed from a patient. With prior art devices, it is common for the medical practitioner to locate a vein on the patient's body and insert a point like cannula needle into the vein for dispersal or extraction of bodily fluids. [0003] General examples of prior art cannula devices can be found in US Patents US 4,874,379, US 5,624,401, US 6,123,689 and US Patent Application No. US 2005/0096594. [0004] The use of cannula devices is not without significant problems. One common problem is the difficulty of accurately locating veins in the patient and ensuring that the vein is readily accessed by the needle. This often leads to increased levels of pain amongst patients when the service provider fails to accurately and succinctly locate the vein for cannula insertion.
Summary of the Invention [0005] It is an object of the present invention to provide for an improved form of cannula device.
[0006] In accordance with a first aspect of the present invention, there is provided a cannula device including (a) a base portion including a first pressure application surface structure to engage the skin surface adjacent a patient's vein; a recessed surface surrounding the skin surface above a patient's vein; a base aperture interconnecting a top surface of the base portion with the recessed surface (b) a top portion slidably mounted in the aperture including a cannula needle slidable from a first position recessed in the aperture to a second position protruding from the aperture into a patient's vein. [0007] The first pressure application surface can be substantially planar and the recessed surface can comprise a recessed elongated channel. The top portion further preferably can include a profiled surface for applying finger pressure to the top portion so as to slide the top portion from the first to the second position. The base portion preferably can include a barrel formed around the aperture. The top portion can be mounted in the barrel formed in the base portion. The walls of the aperture can include a rotation prevention means for preventing the rotation of the base portion relative to the top portion. The side of the barrel preferably can include at least one slot and the top portion preferably can include a pin for slidably moving along the slot. The side walls of the slot are preferably irregularly shaped so that the top portion can be provided with a substantially snap fit in moving from the first position to the second position. The top portion can be detachable from the bottom portion. [0008] The first pressure application surface preferably can include a lip around a distal end thereof. The device can also include a wrist band to which the base portion can be rotateably mounted. The top portion preferably can include a Luer interconnection in fluid interconnection with the cannula needle for interconnecting a flow between the Luer interconnection and the needle.
Brief Description of the Drawings
[0009] Preferred forms of the present invention will now be described with reference to the accompanying drawings in which:
[0010] Fig. 1 illustrates a side cross sectional view of the preferred embodiment before engaging a vein; [0011] Fig. 2 illustrates a bottom plan view of the base portion of the preferred embodiment;
[0012] Fig. 3 illustrates a top plan view of the base portion including a fixing strap;
[0013] Fig. 4 is a side sectional view of the preferred embodiment after the top part has been lowered so that the needle engages a vein; [0014] Fig. 5 illustrates a sectional view showing the needle engaging a vein;
[0015] Fig. 6 is a side sectional view of the base portion of the preferred embodiment;
[0016] Fig. 7 is a bottom plan view of the base portion of an alternative embodiment; [0017] Fig. 8 is a side perspective view of the preferred embodiment before activation; and
[0018] Fig. 9 is a side perspective view of the preferred embodiment after activation Description of Preferred and Other Embodiments
[0019] In Fig. 1, there is illustrated a side perspective view of the cannula device 20 of the preferred embodiment. The device 20 can be formed from injection moulded clear plastic. The device 20 can be formed from two parts including a base part 1 and Luer interconnection top part 12. The end 11 can include a standard Luer locking ring so as to present a standard connection. The base 1 includes a generally flat planer portion 21 and a cross channel 2. The flat portion 21 is placed so as to surround the vein with the central channel 2 being directly over the vein and generally parallel with the vein. Pressure is applied to the platform 9 which causes the top portion 12 to slide within the generally hollow cylindrical portion 22. The barrel 8 slides along the cylinder 22 with alignment knuckle 5 sliding down the grove or slot 7. The needle 4 then protrudes into the vein located within channel 2. Hence, light pressure on the platform 9 causes the needle 4 to project out of the channel 2 into the patient's vein. The needle can then be withdrawn via a reverse process wherein the barrel 8 is drawn up the cylinder 22 thereby retracting the needle from the vein. A series of locating edges along the edge of slot 7 assist in locating the needle in one of the two positions.
[0020] Turning to Fig. 2, there is illustrated a bottom view of the base part 1. The base is again made of clear material so the user can see the location of the needle on the vein. [0021] Turning now to Fig. 3, a strap 18 can be provided for holding the vertical cannula in position for an extended period of time. The strap 18 can be again made from a transparent material and designed to fasten around, for example, the arm of the patient. The strap can be attached to a ring 19 on the barrel portion of the base, so that the base 1 can rotate for appropriate positioning relative to the vein. [0022] Turning to Fig. 4 there is illustrated a sectional view illustrating the movement of the barrel 8 relative to cylinder 6 after pressure has been applied to platform 9. The movement causes needle 4 to protrude into the vein within channel 2. Also shown in Fig. 4 is the ring 19 to which the strap 18 is attached. [0023] Fig. 5 better illustrates the insertion of the needle 4 into the vein 17 which is formed around the channel 2.
[0024] In Fig. 6, there is illustrated a further sectional view of the base portion 1. The upper cylinder 6 includes opposed slots 7 in each wall. The slot 7 further includes a series of slot width fluctuations 24, 25 so as to provide for locating positions for locating pin 5 (Fig. 1) on the top unit. The two sides of the cylinder are designed to flex slightly as the pin of the top portion slides along the edge so as to provide a 'snap fit' feel to the top portion movement. [0025] Further, the arrangement of Fig. 6 also include a number other optional modifications including end lips e.g. 26. As shown in Fig. 7, the end lips e.g. 26 are formed on the outer circumference of the base portion and do not totally surround the base portion. The lips 26 are designed to engage the surface of the skin so as to further hold the cannula unit in place. [0026] By way of further illustration, Fig. 8 is a side perspective view of the preferred embodiment before activation; and Fig. 9 is a side perspective view of the preferred embodiment after activation.
[0027] Overall, the arrangement of the preferred embodiments provides for the insertion of a cannula element into the vein in the correct position whilst not interfering with the blood circulation of the vein as the blood circulation is free to flow along the channel 2.
[0028] The vertical cannula arrangement can be used for administering anaesthesia, medication through a drip system or directly injection through the vertical cannula. Alternatively, the cannula can be utilised for drawing blood for blood tests or blood transfusion. The cannula has two simply made parts with the top part having a standard Luer interconnect and the base part being independently positioned for selecting a vein. The unit provides for simple operation for insertion and retraction of the cannula needle from a vein. The channel 2 can also be made of various sizes so as to cater for different patient types. [0029] The foregoing described preferred forms of the present invention. Modifications, obvious to those skilled in the art can be made thereto without departing from the scope of the invention.