TRANSCUTANEOUS DEVICE FOR REMOVAL OF FLUID FROM A BODY

Abstract

A single step body insertion device comprises a cannula and a Veress needle which penetrates the skin surface and relevant tissue layers to reach fluid and/or gases that need to be removed from the body. The cannula shaft and tapered tip are of a polymeric material which is flexible and kink resistant. The Veress needle has an engagement feature for engagement with the tapered tip of the cannula for delivery of the cannula into the body as the Veress needle is inserted into the body. The device is used for the management of conditions such as pneumothoraxes and pleural effusions as well as other conditions that require release of fluid and/or gas from the body.

Claims

1.-20. (canceled)

21. A single step body insertion device for removal of fluid from a body comprising a cannula having: a cannula shaft; a tapered tip at the distal end of the cannula shaft; and a hub at the proximal end of the cannula shaft, the hub having: a sealing valve aligned with the longitudinal axis of the cannula shaft for sealingly engaging a Veress needle which is adapted to extend through the cannula to penetrate the skin surface to facilitate delivery of the distal end of the cannula for fluid to be removed from the body; and a side port with a one-way valve which permits flow of fluid through the valve only in the proximal direction, wherein the cannula shaft is flexible and kink resistant, the main body of the cannula shaft is of a uniform thickness and the wall thickness progressively reduces inwardly distally along the distal tip of the cannula, wherein the Veress needle has a proximal hub and the cannula has a proximal hub and wherein a releasable interlock is provided between the needle proximal hub and the cannula proximal hub so that when the interlock is engaged the needle and the cannula move together on insertion into the body and when the interlock is released the Veress needle is removable through the cannula hub, and an indicator to provide a visual indication when the interlock between the Veress needle proximal hub and the cannula proximal hub is engaged.

22. A device as claimed in claim 21 wherein the cannula shaft is of a polymeric material with a shore hardness of about 63D.

23. A device as claimed in claim 21 wherein the cannula shaft is of an aliphatic polyether-based thermoplastic polyurethane.

24. A device as claimed in claim 21 wherein the cannula shaft is radiopaque.

25. A device as claimed in claim 21 wherein the inner diameter (IDt) along at least a portion of the tip is less than the inner diameter (IDb) of the main body of the cannula shaft.

26. A device as claimed in claim 25 wherein the difference between IDb and IDt is less than 0.4 mm.

27. A device as claimed in claim 25 wherein the difference between IDb and IDt is less than 0.2 mm.

28. A device as claimed in claim 25 wherein the difference between IDb and IDt is approximately 0.16 mm.

29. A device as claimed in claim 21 wherein the taper angle of the outer surface of the distal tip is from 4 to 13.

30. A device as claimed in claim 29 wherein the taper angle is from 7 to 11.

31. A device as claimed in claim 29 wherein the taper angle is approximately 9.

32. A device as claimed in claim wherein the length of the tapered distal tip is less than 10 mm.

33. A device as claimed in claim 21 wherein the length of the cannula shaft is from 100 to 150 mm.

34. A device as claimed in claim 21 wherein the cannula shaft has an outer diameter in the range of from 2 to 5 mm.

35. A device as claimed in claim 21 wherein the main body of the cannula shaft has a wall thickness in the range of from 0.5 mm to 1 mm.

36. A device as claimed in claim 21 wherein the main body of the cannula shaft has at least one opening in the wall thereof adjacent to the distal tip to provide a further pathway for fluid entry into the cannula shaft.

37. A device as claimed in claim 21 wherein the cannula shaft has indicia thereon to indicate the depth of penetration of the cannula shaft into the body.

38. A device as claimed in claim 21 wherein the side port comprises a connector for mounting of ancillary components to the side port, a three way tap for attachment to the side port, and a syringe for attachment to one of the ports of the three way tap.

39. A device as claimed in claim 21 wherein the one-way valve is a low pressure cracking valve having a cracking pressure of 12 mbar or less.

40. A device as claimed in claim 39 wherein the one-way valve has a backward pressure of up to 6 bar.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0121] The invention will be more clearly understood from the following description of an embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which:

[0122] FIG. 1 is an elevational view of a transcutaneous device according to the invention;

[0123] FIGS. 2 and 3 are detailed views of a side part with low pressure one way cracking valve of the device;

[0124] FIGS. 4 and 5 are isometric and cross sectional views of a hub section of the device;

[0125] FIG. 6 is a cross sectional view of a cannula tip of the device;

[0126] FIG. 7 is an enlarged cross section of the tip;

[0127] FIGS. 8 and 9 illustrate the insertion site for the device in the treatment of a pneumothorax;

[0128] FIG. 10 illustrates the correct insertion method for the device just above the upper border of the third rib (i.e. into the second intercostal space) in the anterior mid-clavicular line, to avoid the intercostal neurovascular bundle for the management of a pneumothorax;

[0129] FIGS. 11 and 12 illustrate the bending of the shaft of the device, in use;

[0130] FIG. 13 illustrates the inserted device with a Veress needle withdrawn and a three way tap attached and a syringe attached to one port of the three way tap;

[0131] FIG. 14 illustrates the inserted device with the Veress needle withdrawn and a three way tap attached and a syringe attached to one port of the three way tap and with the final tap closed;

[0132] FIG. 15 illustrates further embodiment of the device including a to FIG. 14 which comprises the addition of low pressure one way cracking valve to the final port of the three way tap;

[0133] FIG. 16 is an elevational view of an insertion device according to another embodiment of the invention;

[0134] FIG. 17 is a cross sectional view on the line A-A of FIG. 16;

[0135] FIG. 18 is an isometric view of a cannula of the invention;

[0136] FIG. 19 is an isometric view of a Veress needle of the device;

[0137] FIG. 20 is an isometric view of a cannula distal tip of the device;

[0138] FIG. 21 is a cross sectional view of the cannula distal end with a Veress needle extending through the cannula distal tip;

[0139] FIG. 22 is an isometric view of a gripping pad;

[0140] FIG. 23 is an isometric view of the gripping pad of FIG. 22 mounted on the cannula shaft;

[0141] FIGS. 24 to 29 are a series of images of the cannula proximal hub;

[0142] FIG. 30 is a diagram of a drainage bag system; and

[0143] FIG. 31 is a diagram of the drainage system of FIG. 30 attached to a patient.

DETAILED DESCRIPTION

[0144] The device of the invention may be used to treat a number of different conditions as follows. [0145] In a standard pleural effusion an abnormal amount of fluid accumulates around the lung. The excess fluid may accumulate because the body does not handle fluid properly (such as in congestive heart failure, or kidney and liver disease). The fluid in pleural effusions also may result from inflammation, such as in pneumonia, autoimmune disease, and many other conditions. [0146] In a pneumothorax air accumulates in the pleural space due to a tear of the lung which could occur for a number of reasons including a broken rib penetrating the lung or even simply a sac of the lung spontaneously rupturing. [0147] A tension pneumothorax standardly occurs in a trauma situation when a continuous leakage of air into the pleural space may occur following for example a penetrating trauma, and this collapses the lung because the air cannot escape. Progressive build-up of pressure in the pleural space pushes the mediastinum to the opposite haemothorax, and obstructs venous return to the heart. This leads to circulatory instability and may result in traumatic arrest. Needle thoracostomy (NT) is the most rapid method of achieving life-saving access to the pleural space. [0148] During prolonged field care continual treatment of pneumothoraxes can be challenging.

[0149] The pneumothorax may need to be continually drained or have fluid pumped from it over a long period of transportation time.

[0150] Referring to the drawings there is illustrated a single step transcutaneous insertion device for removal of fluid from a body. The device comprises a cannula 1 having a cannula shaft 2 with a tapered distal tip 3 and a proximal hub 4. The hub 4 has a housing part 5 with a sealing valve 6 which is aligned with the longitudinal axis of the cannula shaft 2 and a side port 7 with a housing part having a low pressure one way cracking valve 8 which is attached using a standard Luer lock system. In one embodiment the device comprises a one way low pressure cracking valve that has a cracking pressure of 12 mbar with a backward pressure of up to 6 bar thereby allowing fluid and gases to travel one way but not the other.

[0151] Other components may also be attached to the side port using the Luer lock system as will be described in more detail below.

[0152] A Veress needle 10 has a proximal end 11 and a needle shaft 12 which extends through the proximal sealing valve 6 and the cannula shaft. In a known manner, the distal end of the needle shaft 12 of the Veress needle 10 is used to puncture the skin surface and relevant tissue layers. In the invention the cannula shaft 2 is advanced into the body tracking over the needle shaft 12 to reach fluid and/or gases that need to be removed from the body. When the skin has been punctured and the cannula is in place the Veress needle 10 is removed through the sealing valve 6. The sealing valve 6 may be a silicone valve that prevents fluid flow through the valve when the needle is removed.

[0153] Body fluid flows up through the cannula shaft to the low pressure one way cracking valve 8 at the cannula side port 7 from which it can be drained and/or removed with the aid of a syringe, if necessary.

[0154] The cannula shaft 2 is of a polymeric material which is flexible and kink resistant but has sufficient shore hardness for penetrating through the needle puncture to the site from which fluid is to be removed. The material may be a polyurethane with a shore hardness of about 63D. The cannula shaft is preferably radiopaque. The shaft may contain a radio opaque agent such as barium sulphate at a loading of about 20% by weight. One such material is Tecoflex EG-65D-B20 polyurethane which is an aliphatic polyether-based thermoplastic polyurethane with a 20% loading of barium sulphate and is available from Lubrizol Corporation, 29400 Lakeland Boulevard, Wickliffe, Ohio 44092, USA.

[0155] Referring in particular to FIGS. 6 and 7 importantly, the cannula shaft 2 has a tapered distal tip section 20 to aid penetration. The main body 21 of the cannula shaft is of a uniform thickness and the wall thickness progressively reduces inwardly distally along the distal tip as will be particularly evident from FIG. 5. We have found that this configuration is optimum to provide the balance of properties required. The taper angle of the outer surface of the tip 20 is from 4 to 13, preferably 7 to 11 and ideally about 9. The length of the tip 20 is less than 10 mm and is preferably about 4 mm. The length of the cannula shaft 2 is preferably at least 100 mm, most preferably 100 to 150 mm and in one case about 155 mm.

[0156] The cannula shaft 2 has an outer diameter in the range of from 2 to 5 mm, preferably 3 to 4 mm with in one case about 3.5 mm.

[0157] The wall thickness of the cannula shaft main body 21 is in the range 0.5 mm to 1 mm, preferably about 0.7 mm.

[0158] The inner diameter (IDt) along at least a portion of, and in this case along the full length of, the distal tip 20 is less than the inner diameter (IDb) of the main body of the cannula shaft. Typically IDb>IDt by an amount of less than 0.4 mm, preferably less than 0.2 mm, preferably approximately 0.16 mm. This is important as it ensures that the distal tip closely hugs the needle shaft whilst allowing the needle to be readily inserted and withdrawn. This IDt provides a resistance aid when the needle and cannula are penetrating the skin so that the cannula can easily follow the needle through the skin.

[0159] The main body 21 of the cannula shaft 2 has at least one opening 30 in the side wall thereof adjacent to the distal tip to provide a further pathway for fluid entry into the cannula shaft. The cannula is sufficiently flexible to pig tail following withdrawal of the Veress needle 10 and also contains fenestrations 30 that allow for full fluid and gas functionality even if the primary cannula becomes obstructed. The cannula shaft can be maintained as illustrated in FIGS. 11 and 12 after withdrawal of the Veress needle and can be taped substantially flat for patient comfort and handling.

[0160] The cannula shaft also has indicia 40 marked thereon to indicate the depth of penetration of the cannula shaft into the body. In one embodiment of the invention the Veress needle 11 has a luer connection at the proximal end that allows for attachment of a syringe or other device, if required.

[0161] In one embodiment of the invention the Veress needle 10 has a visual indicator that pushes up when the needle is penetrating the harder skin and muscle layers as it is attached to the Veress protective tip. This visual indicator then pops down on penetrating these layers indicating penetration into the softer cavities of the body. The visual indicator may be luminous and/or made of a material that can be seen at night.

[0162] FIGS. 8 and 9 show the insertion site for the device in the treatment of a pneumothorax. Following location of which side of the chest the pneumothorax is located the insertion site is just above the upper border of the third rib (i.e. into the second intercostal space) in the anterior mid-clavicular line, to avoid the intercostal neurovascular bundle

[0163] FIG. 10 shows the correct insertion method for the device just above the upper border of the third rib (i.e. into the second intercostal space) in the anterior mid-clavicular line, to avoid the intercostal neurovascular bundle for the management of a pneumothorax.

[0164] FIG. 13 shows the inserted device with the Veress needle 10 withdrawn and a three way tap 50 attached and a syringe 51 attached to another port of the three way tap 50. In practice, the flexible nature of the cannula allows the taping of the device to the patient's skin surface.

[0165] FIG. 14 shows the inserted device with the Veress needle 10 withdrawn with a three way tap 50 attached and a syringe 51 attached to another port of the three way tap with the final tap closed. In this embodiment of the invention, if the syringe plunger 51 is withdrawn it will draw fluid and/or gases into the syringe in the direction shown by the blacked out arrows.

[0166] FIG. 15 shows an alternative arrangement to FIG. 12 which comprises the addition of low pressure one way cracking valve 53 to the final port of the three way tap 50. On withdrawal of the syringe plunger 51 fluid and/or gases is withdrawn from the pneumothorax or effusion into the syringe 51 in the direction shown by the blacked out arrows. Subsequent depressing of the syringe 51 pumps the fluid and/or gas out through the one way low pressure valve 53 in the direction indicated by the smaller arrows, thereby providing a simple pump system for effusion and pneumothorax treatment.

[0167] The invention provides a quick, easy, single step insertion device that can be used to manage conditions such pneumothoraxes and effusions particularly by providing a failsafe means to expire fluids and/or gas from the body. Moreover the invention provides for a pump system for the removal of fluid and/or gas from the body in a system that is more simplistic than any currently conceived.

EXAMPLE 1Skin and Tissue Penetration

[0168] The device of the invention successfully penetrated skin/muscle penetration using an uncooked pork belly sample. Uncooked pork belly provides a good human skin/muscle substitute due to its outer tough skin and multiple tissue layers.

EXAMPLE 2Freshly Thawed Cadaver Pleural Cavity Penetration

[0169] A cadaver study was performed with the invention. The device was tested for insertion into a freshly thawed non-embalmed cadaver. The study mimicked the placement of the device for the management of a tension pneumothorax. The device insertion site was located and insertion with the device was as described above. The device successfully penetrated the skin surface.

EXAMPLE 3Embalmed Cadaver Fluid Expiration Test

[0170] Example 2 was repeated using an embalmed cadaver. After insertion, embalming fluid escaped through the Veress needle on entry and after Veress needle withdrawal the fluid escaped through the side port one way crack valve but not through the self-sealing bung. This was representative of the in vivo fluid/gas functionality of the device.

EXAMPLE 4Aspiration Through Three Way Tap

[0171] The device was attached to a three way tap as shown in FIG. 14 with a syringe also attached to the three way tap. The device cannula was inserted into a beaker of water with the Veress needle removed instead of into the pleural cavity as specifically shown in FIG. 14. This set up was intended to mimic the device operation in a pleural effusion or a simple pneumothorax case. The third port on the three way tap was closed and the plunger in the syringe was withdrawn. Water was drawn from the beaker through the cannula and subsequently through the low pressure one way cracking valve into the three way tap and finally into the syringe. This confirmed successful device characteristics for the withdrawing of fluid from the body in such medical management cases as simple pneumothorax or pleural effusion.

EXAMPLE 5Fluid Pumping

[0172] In a similar experimental set-up to Example 4 a low pressure one way cracking valve was added to the final port of the three way tap as can be seen in FIG. 15. The low pressure one way cracking valve was purchased from Promepla SA (part number PBB01050). With this valve it is possible to orientate it so that it is possible to control which direction the fluid and/or gases pass through it.

[0173] As with Example 4, water was drawn from the beaker through the cannula and subsequently through the low pressure one way cracking valve into the three way tap and finally into the syringe. Subsequently when the syringe plunger was depressed, as water cannot pass back through the one way cracking valve on the side port of the device hub it is expelled through the other low pressure one way cracking valve to a collection vessel as that valve is orientated to let fluid out but no air or fluid in to the three way tap. Subsequent withdrawal of the syringe plunger takes up more water, with subsequent depression of the plunger pumping more water from the container. This example demonstrates the simple adaptation of the invention into a manual pump that can be used for the management of certain medical conditions.

EXAMPLE 6Cadaver Pneumothorax Model

[0174] A tension pneumothorax human cadaver thorax model was created. The tension pneumothorax was created by inserting a device as described with reference to FIGS. 1 to 15 through the 5th space between the mid and anterior axillary line. The one-way valve of the device was removed and it was connected to an O2 source. Excessive O2 flow into the pleural space was initiated and as well as obvious resonance difference with the model, mediastinal shift was also clearly visible. The device was then inserted via the 2nd space mid clavicular line. Clear venting occurred which was audible through the device one-way valve that is in the side port of the device. Subsequent to successful alleviation of the tension pneumothorax with the device a similar experimental strategy was used to test the BD Venflon improvised device. However, no venting of the tension pneumothorax occurred. Finally with the unsuccessful BDV still in the 2nd ICS space a device of the invention was placed. Venting of the tension pneumothorax was immediately observed through the device.

[0175] Referring to FIGS. 16 to 30 there is illustrated another single step body insertion device 100 according to the invention. This insertion device has some features similar to those of the insertion device of FIGS. 1 to 15.

[0176] The insertion device 100 comprises a cannula 101 and a Veress needle 102. The cannula 101 comprises a cannula shaft 105 and a tapered tip 106 at a distal end of the shaft 105. The cannula also has a proximal hub 107 with a sealing valve 108 aligned with the longitudinal axis of the cannula for sealing engagement with the shaft 109 of the Veress needle. A side port 110 is provided adjacent to the proximal end of the cannula and the side port 110 has a one-way valve which permits flow of fluid through the valve only in the proximal direction.

[0177] Referring in particular to FIG. 21 the shaft 109 of the Veress needle has an engagement feature for engagement with the tapered tip of the cannula for delivery of the cannula into the body on the Veress needle is inserted into the body. The engagement of the Veress needle may take any form suitable for engagement with the cannula distal tip. For example, the engagement feature may comprise a ridge 120 which engages with an end face 121 of the cannula distal tip.

[0178] The Veress needle enables a hard catheter tip 106 to conform to it. This enables the catheter to be pulled into the human body instead of being pushed into the body. The ability to pull the catheter into the body allows for a significantly softer catheter to be used. This helps to protect the re-inflating lung from damage by the catheter.

[0179] Because the catheter tip is now delivered into the body by the normal insertion action of the Veress needle the cannula shaft 101 can be much softer (and hence have increased flexibility) than the tapered tip 106 of the cannula. In one case the cannula tapered tip and the cannula shaft may be of a polymeric material. They may be of the same or similar polymeric materials, for example different grades of a suitable polymeric material such as an aliphatic polyether-based thermoplastic polyurethane. An example of one such material is an aliphatic polyether-based thermoplastic polyurethane. The cannula is preferably radiopaque, for example the polymer may contain a radio opaque agent such as barium sulphate at a loading of about 20% by weight. Such materials are available for example from Lubrizol Corporation, 29400 Lakeland Boulevard, Wickliffe, Ohio 44092, USA. The resulting cannula is easily inserted into the body. It is kink resistant and radio opaque. It may also be graduated.

[0180] The tapered tip 106 may be attached to the cannula shaft 105 in any suitable manner. In the embodiment illustrated in FIGS. 20 and 21 the tapered tip 106 has a male spigot portion 121 of reduced diameter which is engagable in a sleeve or socket portion 122 at the distal end of the cannula shaft 105. They may be heat sealed and/or bonded together.

[0181] The Veress needle 101 has a proximal hub 130 and a releasable interlock is provided between the needle proximal hub 130 and the cannula proximal hub 107. When the interlock is engaged the needle and the cannula move together on insertion into the body. When the interlock is released the Veress needle is removable through the cannula hub.

[0182] The interlock between the catheter and the Veress needle is advantageous as it prevents incorrect insertion if holding the catheter hub and not the Veress needle hub.

[0183] There may be an indicator 150 to provide a visual indication when the interlock between the Veress needle proximal hub 130 and the cannula proximal hub 107 is engaged and/or disengaged. The indicator may be luminous for enhanced visibility.

[0184] FIGS. 24 to 27 show longitudinal and side views of the cannula hub 107. The hub consists of two parts 125, 126 that link together via four interlocking segments provided by projections 127 on the outer part 126 that engage with grooves or slots 128. This combined hub contains the valve 108 that seals when the Veress needle 101 is removed.

[0185] The Veress needle proximal hub 130 shown in FIGS. 28 and 29 engages via a twist and lock mechanism 151 to the cannula 107 hub. The Veress needle proximal hub 130 can be transparent to allow visualisation of the colour indicator 150 within.

[0186] The insertion device also comprises a gripping pad 140 which, in use, extend radially outwardly from the cannula shaft 105 intermediate the proximal and distal ends of the shaft.

[0187] The pad 140 may be movable relative to the cannula shaft 105 to facilitate engagement by a user. In some cases the pad 140 may be releasably mounted to the cannula shaft.

[0188] The pad 140 aids gripping and assists with infection control and acts as an aid to control the insertion.

[0189] Referring to FIG. 30 there is illustrated a drainage bag 150 connected to the side port 110 of the device. The drainage bag 150 may be placed in a carrier 156 for portability. Such a system has utility in prolonged field care where continual drainage may be required. The system allows for attending medical professionals to manage conditions such as a pneumothorax over long periods of time. Using the syringe, fluid may be drawn from the patient and pumped into the drainage bag. In FIG. 30 160 is a female screw-threaded Luer which is attached to the side port 110. A three-way tap valve 161 is used to divert flow, as required. A syringe may be attached at a flushing port 162 or at a pumping port 164. One-way valves 163 are also provided.

[0190] Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention that may be embodied in other ways. While the preferred embodiment has been described the details may be changed without departing from the invention.

[0191] Modifications and additions can be made to the embodiments of the invention described herein without departing from the scope of the invention. For example, while the embodiments described herein refer to particular features, the invention includes embodiments having different combinations of features. The invention also includes embodiments that do not include all of the specific features described.

REFERENCES

[0192] 1. Barton E D, et al. P. Prehospital needle aspiration and tube thoracostomy in trauma victims: a six year experience with aeromedical crews. J Emerg Med. 1995;13:155-163. [0193] 2. Davis D P, et al. The safety and efficacy of prehospital needle and tube thoracostomy by aeromedical personnel. Prehosp Emerg Care. 2005;9:191-197. [0194] 3. Zengerink, I er al. Needle Thoracostomy in the Treatment of a Tension Pneumothorax in Trauma Patients: What Size Needle? J Trauma. 2008;64:111-114. [0195] 4. Ball, C G et al. Thoracic needle decompression for tension pneumothorax: clinical correlation with catheter length. J can chir, 2010 Vol. 53, No 3 [0196] 5. Harcke, H T et al. Chest Wall Thickness in Military Personnel: Implications for Needle Thoracentesis in Tension Pneumothorax. Journal of Special Operations Medicine 2008 Volume 8, Edition 2. [0197] 6. R Jones, J Hollingsworth. Tension pneumothoraces not responding to needle Thoracocentesis. Emerg Med J 2002;19:176-177 [0198] 7. Groves and Parekh. Death Following Thoracentesis: Investigating The Cause. The Internet Journal of Emergency and Intensive Care Medicine [0199] 8. The prehospital management of chest injuries a consensus statement. Faculty of Pre-hospital Care, Royal College of Surgeons of Edinburgh [0200] 9. Rawlins R, Brown K M, Carr C S, et al. Life threatening haemorrhage after anterior needle aspiration of pneumothoraces. A role for lateral needle aspiration in emergency decompression of spontaneous pneumothorax. Emerg Med J 2003;20:383-4. [0201] 10. Seneff M G, Corwin R W, Gold L H, et al. Complications associated with thoracocentesis. Chest 1986;90:97-100. [0202] 11. Carney M, Ravin C E. Intercostal artery laceration during thoracocentesis. Chest 1979;75:520-2. [0203] 12. Butler K L, Best I M, Weaver W L, et al. Pulmonary artery injury and cardiac tamponade after needle decompression of a suspected tension pneumothorax. J Trauma 2003;54:610-11.