Medical device
This invention relates to a medical device. The device includes an elongate cannula which is insertable into a blood vessel and which is resiliently biased towards a closed condition in which it inhibits fluid flow through the cannula. The cannula is displaceable away from its closed position by the introduction of a displacement arrangement such as a device or instrument or a pressurised fluid and reverts to its closed condition when the displacement arrangement is removed from the cannula to inhibit the flow of blood therethrough. The invention further relates to a needle for use with the medical device, to a kit and to a method of accessing a blood vessel. In addition, it relates to a method of closing an incision in a blood vessel and to a closure member for use in the method.
1. A medical device which includes a cannula having a distal end portion which is insertable into a blood vessel, a proximal end, and a lumen extending through the cannula, in which the distal end portion of the cannula comprises a closure portion formed of a resiliently deformable material that extends longitudinally inwardly from the distal end portion of the cannula for at least part of a length of the cannula, in which the closure portion, is resiliently biased towards a closed configuration in which the closure portion inhibits fluid flow through the cannula, at least from the distal end portion to the proximal end, and which is displaceable against the bias away from the closed configuration of the closure portion to an open configuration by introduction of a needle through the lumen of the cannula and reverts the closure portion to the closed configuration when the needle is removed from the lumen of the cannula, in which the closure portion of the cannula has an arc shape in transverse cross-section when in the closed configuration.
2. The medical device as claimed in claim 1 , in which the resiliently deformable material is a flexible polymeric material.
3. The medical device as claimed in claim 1 , which includes a head to which the distal end portion of the cannula is connected and from which the head protrudes.
4. The medical device as claimed in claim 1 , which includes a head to which the distal end portion of the cannula is connected and from which the head protrudes in which the head is formed of a rigid or semi-rigid material and is provided with gripping formations to facilitate manipulation of the medical device.
5. The medical device as claimed in claim 3 or claim 4 , in which the head is coated with a soft material to improve patient comfort.
6. The medical device as claimed in claim 1 , which includes a head to which the distal end portion of the cannula is connected and from which the head protrudes, in which the cannula includes a proximal end portion which protrudes from the head in a direction opposite to a direction in which the distal end portion protrudes and the proximal end portion is connected in flow communication with the distal end portion.
7. The medical device as claimed in claim 1 , which includes a head to which the distal end portion of the cannula is connected and from which the head protrudes, in which the cannula includes a proximal end portion which protrudes from the head in a direction opposite to a direction in which the distal end portion protrudes and the proximal end portion is connected in flow communication with the distal end portion, in which the proximal end portion is rigid.
8. The medical device as claimed in claim 1 , in which a transverse opening is provided in a side or wall of the cannula at a position closely spaced from the distal end portion thereof.
9. The medical device as claimed in claim 1 , which includes a placement needle on which the cannula is mounted and relative to which the cannula is longitudinally displaceable to facilitate placement of the cannula.
10. The medical device as claimed in claim 1 , which includes a placement needle on which the cannula is mounted and relative to which the cannula is longitudinally displaceable to facilitate placement of the cannula, and which includes a guide wire engagement arrangement configured to engage with a guide wire to facilitate correct placement of the placement needle and hence of the cannula.
11. The medical device as claimed in claim 1 , wherein the closure portion of the cannula has a semi-circular arc shape in transverse cross-section when in the closed configuration.
12. A kit comprising (a) a cutting tipped needle for forming an arc shaped incision in a blood vessel and (b) a cannula having a distal end which is insertable into the blood vessel, a proximal end, and a lumen extending through the cannula, in which the distal end of the cannula comprises a closure portion formed of a resiliently deformable material that extends longitudinally inwardly from the distal end of the cannula for at least part of a length of the cannula, in which the closure portion, is resiliently biased towards a closed configuration in which the closure portion inhibits fluid flow through the cannula, at least from the distal end to the proximal end, and which is displaceable against the bias away from the closed configuration of the closure portion to an open configuration by introduction of a placement needle through the lumen of the cannula and reverts the closure portion to the closed configuration when the placement needle is removed from the lumen of the cannula, in which the closure portion of the cannula has an arc shape in transverse cross-section when in the closed configuration which is complementary in shape to the arc shaped incision formed by the cutting tipped needle to facilitate insertion of the distal end of the cannula into the blood vessel through the arc shaped incision, and in which the cannula is mountable on, and longitudinally displaceable relative to, the cutting tipped needle.
13. The kit of claim 12 , including a second needle having a distal end and a proximal end, the distal end being shaped and dimensioned to be inserted through the lumen of the cannula into flow communication with the blood vessel into which the distal end of the cannula has been inserted.
14. The kit of claim 12 , including a second needle having a distal end and a proximal end, the distal end being shaped and dimensioned to be inserted through the lumen of the cannula into flow communication with the blood vessel into which the distal end of the cannula has been inserted, in which the second needle is selected from:
(a) a dialysis needle, the proximal end of the dialysis needle being connectable in flow communication with a dialysis machine;
(b) a blunt-tipped atraumatic needle which is connected or connectable to a “Vacutainer” or other venepuncture system; and
a syringe or a drip-IV-system into the blood vessel.
15. The kit of claim 12 , wherein
the cutting tipped needle is configured to form a semi-circular arc shaped incision in the blood vessel, and
the closure portion of the cannula has a semi-circular arc shape in transfer cross-section when in the closed configuration which is complementary to the semi-circular arc shaped incision formed by the cutting tipped needle.