US20060235376A1 - Methods and apparatus for hemostasis following arterial catheterization - Google Patents

Abstract

A method for accelerating hemostasis of an artery having a puncture after arterial catheterization, the catheterization using a catheter introducer, the method including the steps of inserting into an artery a catheter introducer prior to arterial catheterization, following arterial catheterization, introducing a hemostasis device into the catheter introducer, such that a forward end of the hemostasis device lies exterior of the artery adjacent a puncture in a wall of the artery, accelerating hemostasis by heating blood in the vicinity of the puncture, thereby shortening the time required for hemostasis and following hemostasis, removing the catheter introducer and hemostasis device from the patient. A method for monitoring the progress of hemostasis of an artery is also disclosed.

Description

FIELD OF THE INVENTION
• The present invention relates to methods and apparatus for hemostasis following arterial catheterization.
BACKGROUND OF THE INVENTION
• Various techniques are known for arterial catheterization. Following arterial catheterization, it is necessary to promote hemostasis quickly and without undue hardship for the patient.
• Applicant's U.S. Pat. Nos. 5,728,134 and 6,048,358, and published PCT Applications WO 98/11830 and WO 00/02488 describe methods and apparatus for hemostasis which greatly simplify hemostasis and thus greatly reduce patient discomfort following arterial catheterization. These patent documents, the disclosures of which are hereby incorporated by reference, and the prior art referenced therein are considered to represent the state of the art.
SUMMARY OF THE INVENTION
• The present invention seeks to provide improved apparatus and techniques for measuring the progress of and accelerating hemostasis.
• There is thus provided in accordance with a preferred embodiment of the present invention a method for monitoring the progress of hemostasis of an artery having a puncture after arterial catheterization, the catheterization using a catheter introducer, the method including the steps of inserting into an artery a catheter introducer prior to arterial catheterization, following arterial catheterization, introducing a hemostasis device into the catheter introducer, such that a forward end of the hemostasis device lies exterior of the artery adjacent a puncture in a wall of the artery, during hemostasis, measuring the heat conductivity of blood in the vicinity of the puncture, thereby to provide an output indication of the progress of hemostasis and following hemostasis, removing the catheter introducer and the hemostasis device from the patient.
• Preferably, the method also includes inflating a balloon attached to the catheter introducer to block the puncture, prior to the introducing a hemostasis device. Additionally, the removing the catheter introducer also includes deflating the balloon prior to removing the catheter introducer.
• There is also provided in accordance with another preferred embodiment of the present invention a method for accelerating hemostasis of an artery having a puncture after arterial catheterization, the catheterization using a catheter introducer, the method including the steps of inserting into an artery a catheter introducer prior to arterial catheterization, following arterial catheterization, introducing a hemostasis device into the catheter introducer, such that a forward end of the hemostasis device lies exterior of the artery adjacent a puncture in a wall of the artery, accelerating hemostasis by heating blood in the vicinity of the puncture, thereby shortening the time required for hemostasis and following hemostasis, removing the catheter introducer and hemostasis device from the patient.
• In accordance with another preferred embodiment of the present invention the method also includes inflating a balloon attached to the catheter introducer to block the puncture, prior to the introducing a hemostasis device. Additionally, the removing the catheter introducer also includes deflating the balloon prior to removing the catheter introducer.
• Alternatively or additionally, the method also includes measuring the heat conductivity of blood in the vicinity of the puncture during hemostasis, thereby to provide an output indication of the progress of hemostasis.
• There is further provided in accordance with still another preferred embodiment of the present invention a hemostasis device including a resistance element, disposed at a forward end of the hemostasis device, a resistance sensor and a resistance indicator, operative to provide an indication of the resistance at the resistance sensor.
• In accordance with another preferred embodiment of the present invention, the hemostasis device also includes a power supply serially connected to the resistance element, the resistance sensor and the resistance indicator. Preferably, the power supply is operative to supply a high level current to the resistance element. Alternatively, the power supply is operative to supply a low level current to the resistance sensor.
BRIEF DESCRIPTION OF THE DRAWINGS
• The present invention will be understood and appreciated more fully from which the following detailed description taken in conjunction with the drawings in which:
• FIGS. 1A and 1B are simplified pictorial illustrations of respective first and second modes of operation of a hemostasis device constructed and operative in accordance with a preferred embodiment of the present invention;
• FIG. 2 is a simplified pictorial illustration of the hemostasis device ofFIGS. 1A and 1B during hemostasis; and
• FIGS. 3A and 3B are graphs illustrating the typical conductivity levels measured by the hemostasis device when used in the operating modes shown inFIGS. 1A and 1B, respectively.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
• Reference is now made toFIGS. 1A and 1B, which are simplified pictorial illustrations of a preferred embodiment of a hemostasis device in respective first and second modes of operation.
• As seen inFIG. 1A, ahemostasis device10 is inserted into a catheter introducer11, following arterial catheterization and withdrawal of a catheter (not shown), such that aforward end12 of thehemostasis device10 lies adjacent to and outside apuncture14 in anartery16. At least oneexternal balloon18 is preferably disposed adjacent catheter introducer11 and is shown in an inflated orientation, wherein theballoon18 forms a skirt surrounding and sealingpuncture14 from the tissue external thereto. At this stage blood normally fillsartery16 as well aspuncture14, as well as theannular volume20 surrounded byballoon18adjacent puncture14 andforward end12.
• In accordance with another preferred embodiment of the present invention, the at least oneballoon18 need not be provided.
• In accordance with a preferred embodiment of the present invention, aresistance element22 is disposed at aforward edge24 of theforward end12, and is coupled in series with anexternal power supply26 viaconductors28, which typically extend along the length of thehemostasis device10. Preferably, the series connection includes aresistance indicator30, which provides an indication of the resistance at aresistance sensor32.
• As seen inFIG. 1A, a low level current, typically less than0.1 ampere, is provided byexternal power supply26 to enable theresistance indicator30 to monitor the progress of hemostasis, to allow for timely removal of catheter introducer11 andhemostasis device10 from the patient.
• It is appreciated that the heat conductivity of the blood in liquid form is measurably different from that of a blood clot formed during hemostasis, as will be described hereinbelow with reference toFIGS. 3A and 3B.
• FIG. 1B illustrates the hemostasis device ofFIG. 1A in a second preferred mode of operation. As shown inFIG. 1B, a high level electrical current, typically greater than 0.1 ampere, is supplied via theexternal power supply26 toresistance element22. The provision of this current causes heating of the blood adjacent to theresistance element22 and provides for accelerated hemostasis. The provision ofresistance indicator30, connected toresistance sensor32, enables the monitoring of the progress of the accelerated hemostasis, to allow for regulation of the current provided toresistance element22 over time, and to allow timely removal of catheter introducer11 andhemostasis device10 from the patient.
• It is appreciated that the heat conductivity of the blood in liquid form is measurably different from that of a blood clot formed during hemostasis, as will be described hereinbelow with reference toFIGS. 3A and 3B.
• Reference is now made toFIG. 2, which is a simplified pictorial illustration ofhemostasis device10 ofFIGS. 1A and 1B during hemostasis.
• FIG. 2 shows thehemostasis device10 ofFIGS. 1A and 1B and illustrates the different heat conductivity of the blood during the various stages of hemostasis. As seen inFIG. 2, the blood flowing through theartery16 and adjacent thepuncture14 in the artery is in liquid form, where its heat conductivity is greater than that of theblood40 which has begun to coagulate.Blood40 is in a viscous form, which has a heat conductivity greater than that of theblood42, which has already begun to solidify into a blood clot.Resistance sensor32 is thus able to measure the process of coagulation by measuring the heat conductivity of the adjacent blood.
• Reference is now made toFIGS. 3A and 3B, which are graphs illustrating the typical conductivity levels measured by the catheter introducer assembly when used in the operating modes shown inFIGS. 1A and 1B, respectively.
• FIG. 3A shows the heat conductivity of the blood over time, in the mode of operation illustrated inFIG. 1A, where the blood is in a liquid form at time T₀, with relatively high heat conductivity, where the heat conductivity decreases gradually over time as the blood forms a clot at time T_H.
• FIG. 3B shows the heat conductivity of the blood over time, in the mode of operation illustrated inFIG. 1B, where the blood is heated to accelerate clotting. As seen inFIG. 3B, the heat conductivity begins at time T₀in a liquid form with relatively high heat conductivity, which decreases rapidly as the blood is heated and the clotting occurs at an accelerated rate.FIG. 3B also shows the heat conductivity curve over time shown inFIG. 3A, which clearly illustrates the accelerated hemostasis described in reference toFIG. 1B hereinabove, where T_HAis the accelerated hemostasis time and T_His the non-accelerated hemostasis time.
• It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as variations and modifications which would occur to persons skilled in the art upon reading the specification and which are not in the prior art.

Claims (11)

1. A method for monitoring the progress of hemostasis of an artery having a puncture after arterial catheterization, said catheterization using a catheter introducer, the method comprising the steps of:

inserting into an artery a catheter introducer prior to arterial catheterization;

following arterial catheterization, introducing a hemostasis device into said catheter introducer, such that a forward end of said hemostasis device lies exterior of the artery adjacent a puncture in a wall of the artery;

during hemostasis, measuring the heat conductivity of blood in the vicinity of said puncture, thereby to provide an output indication of the progress of hemostasis; and

following hemostasis, removing said catheter introducer and said hemostasis device from the patient.

2. A method for monitoring the progress of hemostasis according toclaim 1 and also comprising inflating a balloon attached to said catheter introducer to block said puncture, prior to said introducing a hemostasis device.

3. A method for monitoring the progress of hemostasis according toclaim 2 and wherein said removing said catheter introducer also comprises deflating said balloon prior to removing said catheter introducer.

4. A method for accelerating hemostasis of an artery having a puncture after arterial catheterization, said catheterization using a catheter introducer, the method comprising the steps of:

inserting into an artery a catheter introducer prior to arterial catheterization;

following arterial catheterization, introducing a hemostasis device into said catheter introducer, such that a forward end of said hemostasis device lies exterior of the artery adjacent a puncture in a wall of the artery;

accelerating hemostasis by heating blood in the vicinity of said puncture, thereby shortening the time required for hemostasis; and

following hemostasis, removing said catheter introducer and hemostasis device from the patient.

5. A method for accelerating hemostasis of an artery according toclaim 4 and also comprising inflating a balloon attached to said catheter introducer to block said puncture, prior to said introducing a hemostasis device.

6. A method for accelerating hemostasis of an artery according toclaim 5 and wherein said removing said catheter introducer also comprises deflating said balloon prior to removing said catheter introducer.

7. A method according toclaim 4 and also comprising measuring the heat conductivity of blood in the vicinity of said puncture during hemostasis, thereby to provide an output indication of the progress of hemostasis.

8. A hemostasis device comprising:

a resistance element, disposed at a forward end of said hemostasis device;

a resistance sensor; and

a resistance indicator, operative to provide an indication of the resistance at said resistance sensor.

9. A hemostasis device according toclaim 8 and also comprising a power supply serially connected to said resistance element, said resistance sensor and said resistance indicator.

10. A hemostasis device according toclaim 9 and wherein said power supply is operative to supply a high level current to said resistance element.

11. A hemostasis device according toclaim 9 and wherein said power supply is operative to supply a low level current to said resistance sensor.

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