Hemostatic sleeve for use with a catheter

Abstract: The device for use with a catheter includes a sleeve 21 for assembly onto the shaft of a catheter 1, between the catheter shaft and a Tuohy-Borst connector 3. The internal diameter of the sleeve 21 is complementary with the external diameter of the catheter 1 so that the catheter is movable within the sleeve. The external diameter of the sleeve is such that when the Tuohy-Borst connector is closed, a seal is formed between the sleeve and the connector. A flange 24 is provided at one end of the device for engagement with the connector, to prevent movement of the sleeve with the catheter. The internal diameter of the sleeve 21 is also complementary with the external diameter of the catheter 1 so as to provide an annular space about the catheter whereby, in use, a controlled amount of backbleed of blood is allowed.

Description: The present invention relates to a device for use with a catheter by medical personnel. Catheters may be introduced into the human body as part of diagnostic or treatment procedures. They are introduced into organs, for example the heart, via blood vessels which lead into the organ. In standard use, the technique for advancing a catheter and wire requires the opening of a Tuohy-Borst connector mounted on the catheter, moving the catheter to its required site within the body and reclosing the connector. The standard practice presents a number of difficulties. Firstly, overtightening of the Tuohy-Borst connector on reclosure can impair catheter movement and manipulation. Secondly, small diameter catheters make positive, sealing, closure of the Tuohy-Borst connector difficult. Thirdly, during manipulation of the catheter while the Tuohy-Borst connector is open, severe backbleed occurs from the blood vessels. The backbleed may continue for an extended period while the catheter is being positioned, resulting in considerable loss of blood for the patient. The rate of backbleed is related to the outside diameter of the catheter so that as the catheter shaft diameter decreases, the rate of backbleed increases. The object of the present invention is to seek to overcome the above difficulties. One known valve described in EP 0 267 584 A (Cordis) is designed to permit advancement of catheters and guide wires without blood leakage through the application of a low pressure seal which remains even when the high pressure seal is released (see figure 2A, lips (44) of gasket (30)). The present invention provides an assembly comprising a Tuohy-Borst connector, a device and a complementary catheter, as characterized by the features of claim 1. In particular, the internal diameter of the sleeve is complementary with the external diameter of the catheter so as to provide an annular space about the catheter whereby, in use, a controlled amount of backbleed of blood is allowed. The controlled backbleed prevents thrombosis which would otherwise occur when blood collects in restricted spaces. Alternatively, a sealing element may be provided about the external surface of the sleeve so as to prevent blood from entering the restricted space between the external diameter of the sleeve and the internal diameter of the connector. Conveniently, the sealing element is provided at or towards the distal end of the sleeve. In this way, blood is prevented from entering the restricted space of the connector. Conveniently, a portion of the sleeve adjacent the shoulder is of an enlarged diameter relative to the diameter of the remainder of the sleeve thereby providing a region of greater cross-sectional area intermediate the shoulder and the other end of the sleeve. In use, the Tuohy-Borst connector closes onto the external diameter of the sleeve, thus creating a seal between the Tuohy-Borst connector without impairing freedom of movement of the catheter within the sleeve. The effect of the device is to considerably reduce (though not totally eliminate) the backbleed of blood which occurs between the catheter and the internal diameter of the sleeve. The device may be composed of any suitable material such as a metal or plastic, and may if required be coated with a non-stick material such as PTFE. The sleeve portion of the device must however be sufficiently rigid to prevent the sealing ring of the Tuohy-Borst connector from restricting the internal diameter of the sleeve. The inner surface should have low frictional characteristics to allow for ease of movement of the catheter within it. The term "catheter" is to be read as embracing both a guide wire and a probe. The invention will now be described more particularly with reference to the accompanying drawings which show by way of example only, one embodiment of a device according to the invention. In the drawings: Figure 1 is a cross-sectional side view of a device mounted on the shaft of a catheter; Figure 2 is a sectional view as in Figure 1 showing additionally a Tuohy-Borst connector engaged with the device. Figure 3 is a side view of an assembly of a Tuohy-Borst connector sleeve, guide catheter and probe. Referring now to Figure 1, the catheter 1 is engaged with a device 2 having a sleeve 21 with a shoulder 22. The internal diameter of the sleeve 21 is complementary with the external diameter of the catheter 1. The end of the sleeve 21 adjacent the shoulder 22 has a region 23 of greater cross-sectional area which strengthens the device. Turning now to Figures 2 and 3, the catheter 1 and device 2 have a Tuohy-Borst connector 3 mounted thereon. The connector 3 may be tightened or loosened on the assembly by engagement or release respectively of the sealing ring 4 by means of the screw 5. A guide catheter 10 is connected to the other end of the connector 3. In use, the screw 5 is tightened to exert pressure on the sleeve 21 but not on the guide wire or catheter 1, thus stemming backbleed between the connecter 3 and sleeve 21 but not between the sleeve 21 and catheter 1. Such an arrangement allows the catheter 1 to be moved, but considerably reduces backbleed which would otherwise occur, in the absence of the sleeve 21. While the catheter 1 is being moved into the blood vessel, in the direction shown by the arrow A, the sleeve 21 is prevented from being displaced with the catheter 1 by virtue of the flange 22 which engages over the edges of the connector 3. EXAMPLE 1. In the following example the leakage rate between an open Tuohy-Borst connector and a balloon catheter having a PTFE sleeve was determined. The Tuohy-Borst was left in an open position thereby ensuring that the normal blood pressure (120/80) would be completely exerted on the Teflon sleeve. Using water, a pressure of 120 mm Hg was induced into the entire system and the leakage rate was measured over a period of 5 mins. Sleeve ID 0.047", 3.5F Shaft Diameter. RESULTS: Quantity after 5 mins. = 2.5 ml. Leakage rate = 0.5 ml/min. With water leaking at this rate, it may be correct to suggest that with blood, which has a viscosity approximately 3.5 times greater than that of water, the leakage rate would be adversely affected i.e. leakage rate would be lower. EXAMPLE 2. A similar procedure to that of example 1 was carried out using a solution of glycerine and milk, which possessed similar flow characteristics as blood. No significant difference from water was found in the leakage rate.

Claims: An assembly comprising a Tuohy-Borst connector (3), a device (2) and a complementary catheter (1), the connector (3) having proximal and distal ends, being adapted to receive freely the catheter introduced through said proximal end and having seal means (4) within the connector for engaging the received catheter (1) and providing a seal between the connector (3) and the received catheter (1), the device (2) comprising a sleeve (21) for assembly onto the shaft of the catheter (1) between the catheter shaft and a Tuohy-Borst connector (3), the internal diameter of the sleeve (21) is greater than and complementary with the external diameter of the catheter (1) received within said sleeve (21) so that the catheter (1) is movable within the sleeve (21), characterized in that the sleeve (21) is an elongate, narrow cross-sectional tube and has a shoulder (22) which engages the outside of the proximal end of the connector (3), and the sleeve defines a space about the catheter (1) within and along the length of said sleeve (21) sufficient to allow backbleed of blood therethrough in a controlled manner, and the external diameter of the sleeve (21) is such that when the Tuohy-Borst connector is closed, a seal is formed between the outer surface of the sleeve (21) and the connector (3) said sleeve (21) having sufficient rigidity to maintain said defined space for a controlled amount of backbleed of blood therethrough and without impairing freedom of movement of the catheter within the sleeve. An assembly as claimed in Claim 1, in which the device (2) includes a portion of the sleeve adjacent the shoulder (22) of an enlarged diameter relative to the diameter of the remainder of the sleeve (21) thereby providing a region (23) of greater cross-sectional area intermediate the shoulder (22) and the other end of the sleeve (21). An assembly as claimed in Claim 1 or Claim 2, in which the device (2) is manufactured from a material having low frictional characteristics. An assembly as claimed in any one of the preceding claims, in which the device (2) includes a sealing element provided about the external surface of the sleeve (21), the sealing element being adapted to cooperate with the internal surface of the connector (3) so as to prevent blood from entering the restricted space between the external diameter of the sleeve and the internal diameter of the connector. An assembly as claimed in Claim 4, in which the sealing element is provided at or towards the distal end of the sleeve (21).

Inventors: GILSON JAMES PAUL, RICKARDS ANTHONY F ROYAL BROMP, GILSON, JAMES PAUL, RICKARDS, ANTHONY F. ROYAL BROMPTON NATIONAL
Applicants: BARD CONNAUGHT
Application year: 1991
Main classification: A61M25
IPC codes: A61M25, A61M39