WO2001076479A1 - Catheter for measuring the impedance of surrounding blood - Google Patents

Catheter for measuring the impedance of surrounding blood Download PDF

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Publication number
WO2001076479A1
WO2001076479A1 PCT/NL2001/000281 NL0100281W WO0176479A1 WO 2001076479 A1 WO2001076479 A1 WO 2001076479A1 NL 0100281 W NL0100281 W NL 0100281W WO 0176479 A1 WO0176479 A1 WO 0176479A1
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WIPO (PCT)
Prior art keywords
catheter
electrodes
characterized
distal end
measuring
Prior art date
Application number
PCT/NL2001/000281
Other languages
French (fr)
Inventor
Gheorghe Aurel Marie Pop
Original Assignee
Martil Instruments B.V.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to NL1014851 priority Critical
Priority to NL1014851 priority
Application filed by Martil Instruments B.V. filed Critical Martil Instruments B.V.
Publication of WO2001076479A1 publication Critical patent/WO2001076479A1/en

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/02Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/02028Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
    • A61B5/02035Determining blood viscosity

Abstract

The present invention relates to a catheter (1) for measuring the impedance of surrounding blood, comprising a catheter body (2), which comprises close to the distal end (3) thereof at least four electrodes (4) at mutual distances from each other, and connecting lines (5) extending through the catheter body from the electrodes to the proximal end of the catheter.

Description

CATHETER FOR MEASURING THE IMPEDANCE OF SURROUNDING BLOOD

The present invention relates to a catheter for measuring the impedance of surrounding blood.

Atherosclerosis is the most common disease in the western world and thereby represents one of the most significant problems of our health care services and our society. Atherosclerosis is a generalized disorder of the blood vessels, which can manifest itself for instance in the coronaries in unstable angina pectoris, myocardial infarction or even acute heart death. Atherosclerosis in the head is for instance responsible for the largest number of strokes (cerebral infarction) , while elsewhere in the body atherosclerosis can be the cause of reduced blood circulation in for instance the legs or the kidneys. Significant factors in the development of atherosclerotic complications are, amongst others, thrombotic processes. The treatment of atherosclerosis therefore generally focusses on suppressing such thrombotic processes. More recently it has been further discovered that inflammatory processes also appear to play a part in the occurrence of atherosclerotic complications .

The present invention has for its object to provide a catheter for measuring the impedance of surrounding blood, in particular for the purpose of determining the blood viscosity, whereby it is possible to monitor such thrombotic and/or inflammatory processes.

This object is achieved with the present invention by providing a catheter, comprising a catheter body, which comprises close to the distal end thereof at least four electrodes at mutual distances from each other, and connecting lines extending through the catheter body from the electrodes to the proximal end of the catheter. Using the catheter according to the invention impedance measurements of surrounding tissue, such as blood, can be performed, for instance in the heart, via the electrodes. It is known that blood has electrical properties. These electrical properties are different for the plasma and the blood cells. The plasma and the interior of the cells consist of conductive fluids with a determined electrical resistance and the cell membranes consist of phospholipids and proteins with dielectric properties. The electrical impedance of blood is primarily determined by three parameters: the plasma resistance, the internal resistance in the cell, and the capacitance of the cell membrane. The electrical impedance of the blood increases with an increased viscosity of the blood. The electrical impedance of blood is also found to be closely related to the fibrinogen content and the erythrocyte sedimentation rate, significant "markers" for the presence of inflammatory processes. The application of the catheter for instance for in vivo determining of the blood viscosity is based on the determining of the blood impedance as described in the Netherlands patent application number 1012223 and the international PCT application PCT/NL00/00378.

In a particular embodiment of the catheter according to the present invention the at least four electrodes comprise at least two voltage electrodes, which can be connected via the connecting lines to an alternating voltage source, and two measuring electrodes situated therebetween, which can be connected to a measuring unit via the connecting lines. Using the alternating voltage source connected to the voltage electrodes, an electric alternating voltage field with a determined frequency is generated for instance in the blood for a determined time, wherein using the measuring electrodes connected to the measuring unit a measuring signal of the electrical impedance of the blood is measured during this determined time. The measured measuring signal is then compared to a predetermined relation between the measured impedance and the blood viscosity.

In order to obtain reliable measurement results, the measuring electrodes are preferably arranged symmetrically relative to the centre between the voltage electrode. In a particularly suitable embodiment the mutual distances between the four electrodes are equal . The mutual distance between the measuring electrodes is preferably as small as possible, for instance between 0.5 and 2 mm, wherein the signal/noise ratio must be such that reliable measurements can still be made. Limiting the distance between the measuring electrodes as much as possible ensures that the field around the catheter in which measurement is taking place is as small as possible. The most reliable possible measurement of the impedance of the surrounding blood is hereby obtained, and for instance the vascular wall or the wall of the atrium are prevented from influencing the impedance measurement of the blood.

Each electrode is connected to a connecting wire which runs from the electrode through the catheter body to the proximal end of the catheter. In order to obtain shielding against stray capacitance, which can occur particularly when measurement takes place using alternating voltage, at least one shielding wire is arranged between two connecting wires. In a particularly suitable embodiment each connecting wire is enclosed by two parallel shielding wires. Herein the connecting wires are preferably carried helically at a mutual distance from each other as a " flat cable" from the distal end, where the electrodes are arranged, to the proximal end around a central core in the catheter body. The connecting wire is here thus enclosed by a "layer" of shielding wires. The shielding wires can remain loose, i.e. not connected, or be connected to the proximal end with a zero potential. A charge can also be applied to the shielding wires in order to obtain "active shielding" . This is especially relevant when higher frequencies are used, particularly at frequencies above 1 MHz.

In a special preferred embodiment of the catheter six electrodes are arranged at a mutual distance from Φ

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catheter the catheter body is for instance adapted such that the outer distal end of the catheter body comes to rest on the apex of the right-hand ventricle, wherein the electrodes are situated in the atrium of the heart . In this case the most distal electrode must be arranged further from the extreme distal end such that the most distal electrode comes to lie above the level of the tricuspid valve, so that the impedance measurement is performed in the right-hand atrium. According to a further preferred embodiment the electrodes are annular electrodes which are arranged close to the distal end of the catheter body. The electrodes are preferably platinum or stainless steel electrodes. The transfer resistance which results on the electrode surface increases as the surface decreases.

This resistance (impedance) may not become too great in respect of the compliance (operating range) of the voltage source.

The catheter according to the invention as described above can be suitably used for instance for in vivo determining of the blood viscosity of human or animal, as described earlier in for instance PCT/NL00/00378. Determining the blood viscosity in a patient can be used to evaluate the chance of thrombosis formation, and thereby the risk of thrombotic disorders such as a myocardial or cerebral infarction. When the measurement indicates a high viscosity, it may for instance be decided to apply viscosity-reducing therapy, such as the administering of a fibrinogen-reducing agent. By monitoring the effect of the administered agent on the viscosity, the ideal dosage of the agent can be precisely determined.

The invention is further elucidated with reference to the annexed figures, in which: Fig. 1 shows a schematic view of a preferred embodiment of the catheter with four electrodes;

Fig. 2 is a schematic, partly cut-away view of the human heart provided with the catheter shown in Fig. 1; Fig. 3 shows a schematic view of another preferred embodiment of the catheter according to the invention, provided with six electrodes.

Fig. 1 shows a schematic representation of a preferred embodiment of catheter 1 according to the invention. Catheter 1 herein comprises a catheter body 2, which close to the distal end 3 thereof comprises four annular platinum or stainless steel electrodes 4 (for instance 0.8 mm wide) at mutual distances from each other. Connecting lines 5 extend from electrodes 4 through the catheter body to the proximal end 6 thereof, where they can be connected to for instance an alternating voltage source and a measuring unit .

In the shown embodiment the mutual distances between the electrodes are equal (about 2 mm from the centre of a first electrode to the centre of a subsequent electrode) . The distal end on which the electrodes are arranged is situated during the impedance measurement in for instance the right-hand atrium at an angle relative to the rest of catheter body 2, as shown in figure 2. The most distal electrode is herein arranged at least 1 mm from the end, and the top of the distal end is preferably soft so as to prevent damage of the atrium wall by the most distal electrode. The other part of the catheter body is preferably made from a stiff material so as to ensure that the catheter can be repositioned from the outside such that the distal end with the electrodes remains centrally in the atrium.

As shown in Fig. 2, catheter 1 comprises an intravascular part 2 intended for placing in the bloodstream, which part is embodied such that the distal end with the at least four electrodes for performing the impedance measurement can be placed in the right-hand atrium 8 of a human heart 7. By way of orientation the right-hand ventricle is further designated in figure 2 with 9, the sino-atrial node with 10, and the atrioventricular bundle with 11. The distal end of catheter body 2 with the four electrodes is shown in area 12. During the impedance measurement the distal end is situated in right-hand atrium 8 at an angle relative to the rest of catheter body 2, such that the electrodes lie as centrally as possible in the atrium.

Finally, Fig. 3 shows a schematic representation of another preferred embodiment of catheter 1 according to the invention. Six electrodes 4 are herein arranged close to the distal end 3 of catheter body 2, wherein a connecting wire 5 runs from each electrode through the catheter body to the proximal end 6 of the catheter, and wherein each electrode is enclosed by two shielding wires. The most distal electrode is herein arranged at a greater distance, for instance about 12 cm, from the distal end. The embodiment of the catheter shown in these figures is for instance particularly suitable for use in the application where the tip of the distal end comes to rest on the apex of the right-hand ventricle. Because the electrodes are arranged at a greater distance from the distal end it is possible to ensure that the voltage electrodes and the measuring electrodes measure the impedance of the blood in the atrium. If the dimensions of the heart for sampling are for instance such that the most distal electrode or electrodes do not lie above the level of the tricuspid valve, four more proximally situated electrodes can be used for the measurement. It will be further understood that the dimensions given above can be varied, for instance depending on the size of the heart for which the catheter is intended, such as for instance human or animal.

Claims

1. Catheter for measuring the impedance of surrounding blood, comprising a catheter body, which comprises close to the distal end thereof at least four electrodes at mutual distances from each other, and connecting lines extending through the catheter body from the electrodes to the proximal end of the catheter.
2. Catheter as claimed in claim 1, characterized in that the at least four electrodes comprise at least two voltage electrodes, which can be connected via the connecting lines to an alternating voltage source, and two measuring electrodes situated therebetween, which can be connected to a measuring unit via the connecting lines .
3. Catheter as claimed in claim 1 or 2 , characterized in that the measuring electrodes are arranged symmetrically relative to the centre between the voltage electrode.
4. Catheter as claimed in claim 1, 2 or 3 , characterized in that the mutual distance between the four electrodes is equal.
5. Catheter as claimed in any of the claims 1-4, characterized in that at least one shielding wire is arranged between two connecting wires.
6. Catheter as claimed in any of the claims 1-5, characterized in that each connecting wire is enclosed by two parallel shielding wires.
7. Catheter as claimed in any of the foregoing claims, characterized in that the connecting wires are carried helically at a mutual distance from each other as a "flat cable" from the distal end, where the electrodes are arranged, to the proximal end around a central core in the catheter body.
8. Catheter as claimed in any of the foregoing claims, characterized in that six electrodes are arranged at a mutual distance from each other close to the distal end of the catheter body.
9. Catheter as claimed in any of the foregoing claims, characterized in that the catheter body comprises an elongate intravascular part intended for placing in the blood, which part is embodied such that the at least four electrodes for performing the impedance measurement can be placed in the right-hand atrium of the heart.
10. Catheter as claimed in claim 9, characterized in that the most distal of the at least four electrodes is arranged at least about 1 mm from the distal end of the catheter body.
11. Catheter as claimed in claim 9 or 10, characterized in that the distal end with the at least four electrodes can be placed in the right-hand atrium of the heart at an angle of between 0 and 180 °C relative to the catheter body.
12. Catheter as claimed in any of the foregoing claims, characterized in that the electrodes are annular electrodes.
13. Catheter as claimed in any of the foregoing claims, characterized in that the electrodes are platinum or stainless steel electrodes.
14. Use of a catheter as claimed in any of the foregoing claims for determining the blood viscosity of a human or animal .
PCT/NL2001/000281 2000-04-06 2001-04-06 Catheter for measuring the impedance of surrounding blood WO2001076479A1 (en)

Priority Applications (2)

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NL1014851 2000-04-06

Applications Claiming Priority (1)

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Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1021183C2 (en) 2002-03-20 2003-09-23 Martil Instr B V A catheter with an integrated signal processing device.
WO2009123508A1 (en) * 2008-03-31 2009-10-08 St. Jude Medical Ab Anti-arrhythmia implantable medical device
US8103326B2 (en) 2004-08-02 2012-01-24 Cardiac Pacemakers, Inc. Device for monitoring fluid status
US8388541B2 (en) 2007-11-26 2013-03-05 C. R. Bard, Inc. Integrated system for intravascular placement of a catheter
US8388546B2 (en) 2006-10-23 2013-03-05 Bard Access Systems, Inc. Method of locating the tip of a central venous catheter
US8437833B2 (en) 2008-10-07 2013-05-07 Bard Access Systems, Inc. Percutaneous magnetic gastrostomy
US8478382B2 (en) 2008-02-11 2013-07-02 C. R. Bard, Inc. Systems and methods for positioning a catheter
US8512256B2 (en) 2006-10-23 2013-08-20 Bard Access Systems, Inc. Method of locating the tip of a central venous catheter
USD699359S1 (en) 2011-08-09 2014-02-11 C. R. Bard, Inc. Ultrasound probe head
US8781555B2 (en) 2007-11-26 2014-07-15 C. R. Bard, Inc. System for placement of a catheter including a signal-generating stylet
US8784336B2 (en) 2005-08-24 2014-07-22 C. R. Bard, Inc. Stylet apparatuses and methods of manufacture
US8801693B2 (en) 2010-10-29 2014-08-12 C. R. Bard, Inc. Bioimpedance-assisted placement of a medical device
US8849382B2 (en) 2007-11-26 2014-09-30 C. R. Bard, Inc. Apparatus and display methods relating to intravascular placement of a catheter
US9125578B2 (en) 2009-06-12 2015-09-08 Bard Access Systems, Inc. Apparatus and method for catheter navigation and tip location
US9211107B2 (en) 2011-11-07 2015-12-15 C. R. Bard, Inc. Ruggedized ultrasound hydrogel insert
US9339206B2 (en) 2009-06-12 2016-05-17 Bard Access Systems, Inc. Adaptor for endovascular electrocardiography
US9445734B2 (en) 2009-06-12 2016-09-20 Bard Access Systems, Inc. Devices and methods for endovascular electrography
US9456766B2 (en) 2007-11-26 2016-10-04 C. R. Bard, Inc. Apparatus for use with needle insertion guidance system
US9492097B2 (en) 2007-11-26 2016-11-15 C. R. Bard, Inc. Needle length determination and calibration for insertion guidance system
US9521961B2 (en) 2007-11-26 2016-12-20 C. R. Bard, Inc. Systems and methods for guiding a medical instrument
US9532724B2 (en) 2009-06-12 2017-01-03 Bard Access Systems, Inc. Apparatus and method for catheter navigation using endovascular energy mapping
US9554716B2 (en) 2007-11-26 2017-01-31 C. R. Bard, Inc. Insertion guidance system for needles and medical components
US9636031B2 (en) 2007-11-26 2017-05-02 C.R. Bard, Inc. Stylets for use with apparatus for intravascular placement of a catheter
US9649048B2 (en) 2007-11-26 2017-05-16 C. R. Bard, Inc. Systems and methods for breaching a sterile field for intravascular placement of a catheter
US9839372B2 (en) 2014-02-06 2017-12-12 C. R. Bard, Inc. Systems and methods for guidance and placement of an intravascular device
US9901714B2 (en) 2008-08-22 2018-02-27 C. R. Bard, Inc. Catheter assembly including ECG sensor and magnetic assemblies
US10046139B2 (en) 2010-08-20 2018-08-14 C. R. Bard, Inc. Reconfirmation of ECG-assisted catheter tip placement

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US4437474A (en) * 1982-07-16 1984-03-20 Cordis Corporation Method for making multiconductor coil and the coil made thereby
US4836214A (en) * 1986-12-01 1989-06-06 Bomed Medical Manufacturing, Ltd. Esophageal electrode array for electrical bioimpedance measurement
EP0384060A2 (en) * 1989-02-13 1990-08-29 Cardiac Pacemakers, Inc. (a Minnesota corporation) Method and apparatus for matching the sensed length of an impedance measuring catheter to a ventricular chamber
WO1994022367A1 (en) * 1993-03-30 1994-10-13 Pfizer Inc. Radiotelemetry impedance plethysmography device
NL1012223C2 (en) 1999-06-03 2000-12-06 Martil Instr B V A heart pacemaker as well as pacemaker unit and electric wires therefor.

Patent Citations (6)

* Cited by examiner, † Cited by third party
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US4437474A (en) * 1982-07-16 1984-03-20 Cordis Corporation Method for making multiconductor coil and the coil made thereby
US4836214A (en) * 1986-12-01 1989-06-06 Bomed Medical Manufacturing, Ltd. Esophageal electrode array for electrical bioimpedance measurement
EP0384060A2 (en) * 1989-02-13 1990-08-29 Cardiac Pacemakers, Inc. (a Minnesota corporation) Method and apparatus for matching the sensed length of an impedance measuring catheter to a ventricular chamber
WO1994022367A1 (en) * 1993-03-30 1994-10-13 Pfizer Inc. Radiotelemetry impedance plethysmography device
NL1012223C2 (en) 1999-06-03 2000-12-06 Martil Instr B V A heart pacemaker as well as pacemaker unit and electric wires therefor.
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Cited By (48)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1021183C2 (en) 2002-03-20 2003-09-23 Martil Instr B V A catheter with an integrated signal processing device.
WO2003077759A1 (en) 2002-03-20 2003-09-25 Martil Instruments B.V. Catheter with integrated signal-processing device
US8103326B2 (en) 2004-08-02 2012-01-24 Cardiac Pacemakers, Inc. Device for monitoring fluid status
US10004875B2 (en) 2005-08-24 2018-06-26 C. R. Bard, Inc. Stylet apparatuses and methods of manufacture
US8784336B2 (en) 2005-08-24 2014-07-22 C. R. Bard, Inc. Stylet apparatuses and methods of manufacture
US8388546B2 (en) 2006-10-23 2013-03-05 Bard Access Systems, Inc. Method of locating the tip of a central venous catheter
US8858455B2 (en) 2006-10-23 2014-10-14 Bard Access Systems, Inc. Method of locating the tip of a central venous catheter
US9833169B2 (en) 2006-10-23 2017-12-05 Bard Access Systems, Inc. Method of locating the tip of a central venous catheter
US8512256B2 (en) 2006-10-23 2013-08-20 Bard Access Systems, Inc. Method of locating the tip of a central venous catheter
US9345422B2 (en) 2006-10-23 2016-05-24 Bard Acess Systems, Inc. Method of locating the tip of a central venous catheter
US8774907B2 (en) 2006-10-23 2014-07-08 Bard Access Systems, Inc. Method of locating the tip of a central venous catheter
US9265443B2 (en) 2006-10-23 2016-02-23 Bard Access Systems, Inc. Method of locating the tip of a central venous catheter
US9526440B2 (en) 2007-11-26 2016-12-27 C.R. Bard, Inc. System for placement of a catheter including a signal-generating stylet
US9649048B2 (en) 2007-11-26 2017-05-16 C. R. Bard, Inc. Systems and methods for breaching a sterile field for intravascular placement of a catheter
US8849382B2 (en) 2007-11-26 2014-09-30 C. R. Bard, Inc. Apparatus and display methods relating to intravascular placement of a catheter
US9681823B2 (en) 2007-11-26 2017-06-20 C. R. Bard, Inc. Integrated system for intravascular placement of a catheter
US9636031B2 (en) 2007-11-26 2017-05-02 C.R. Bard, Inc. Stylets for use with apparatus for intravascular placement of a catheter
US9554716B2 (en) 2007-11-26 2017-01-31 C. R. Bard, Inc. Insertion guidance system for needles and medical components
US9549685B2 (en) 2007-11-26 2017-01-24 C. R. Bard, Inc. Apparatus and display methods relating to intravascular placement of a catheter
US8781555B2 (en) 2007-11-26 2014-07-15 C. R. Bard, Inc. System for placement of a catheter including a signal-generating stylet
US10231753B2 (en) 2007-11-26 2019-03-19 C. R. Bard, Inc. Insertion guidance system for needles and medical components
US10105121B2 (en) 2007-11-26 2018-10-23 C. R. Bard, Inc. System for placement of a catheter including a signal-generating stylet
US10238418B2 (en) 2007-11-26 2019-03-26 C. R. Bard, Inc. Apparatus for use with needle insertion guidance system
US10165962B2 (en) 2007-11-26 2019-01-01 C. R. Bard, Inc. Integrated systems for intravascular placement of a catheter
US8388541B2 (en) 2007-11-26 2013-03-05 C. R. Bard, Inc. Integrated system for intravascular placement of a catheter
US9456766B2 (en) 2007-11-26 2016-10-04 C. R. Bard, Inc. Apparatus for use with needle insertion guidance system
US9492097B2 (en) 2007-11-26 2016-11-15 C. R. Bard, Inc. Needle length determination and calibration for insertion guidance system
US9521961B2 (en) 2007-11-26 2016-12-20 C. R. Bard, Inc. Systems and methods for guiding a medical instrument
US9999371B2 (en) 2007-11-26 2018-06-19 C. R. Bard, Inc. Integrated system for intravascular placement of a catheter
US8478382B2 (en) 2008-02-11 2013-07-02 C. R. Bard, Inc. Systems and methods for positioning a catheter
US8971994B2 (en) 2008-02-11 2015-03-03 C. R. Bard, Inc. Systems and methods for positioning a catheter
WO2009123508A1 (en) * 2008-03-31 2009-10-08 St. Jude Medical Ab Anti-arrhythmia implantable medical device
US9901714B2 (en) 2008-08-22 2018-02-27 C. R. Bard, Inc. Catheter assembly including ECG sensor and magnetic assemblies
US8437833B2 (en) 2008-10-07 2013-05-07 Bard Access Systems, Inc. Percutaneous magnetic gastrostomy
US9907513B2 (en) 2008-10-07 2018-03-06 Bard Access Systems, Inc. Percutaneous magnetic gastrostomy
US10231643B2 (en) 2009-06-12 2019-03-19 Bard Access Systems, Inc. Apparatus and method for catheter navigation and tip location
US9532724B2 (en) 2009-06-12 2017-01-03 Bard Access Systems, Inc. Apparatus and method for catheter navigation using endovascular energy mapping
US9339206B2 (en) 2009-06-12 2016-05-17 Bard Access Systems, Inc. Adaptor for endovascular electrocardiography
US9125578B2 (en) 2009-06-12 2015-09-08 Bard Access Systems, Inc. Apparatus and method for catheter navigation and tip location
US9445734B2 (en) 2009-06-12 2016-09-20 Bard Access Systems, Inc. Devices and methods for endovascular electrography
US10271762B2 (en) 2009-06-12 2019-04-30 Bard Access Systems, Inc. Apparatus and method for catheter navigation using endovascular energy mapping
US10046139B2 (en) 2010-08-20 2018-08-14 C. R. Bard, Inc. Reconfirmation of ECG-assisted catheter tip placement
US9415188B2 (en) 2010-10-29 2016-08-16 C. R. Bard, Inc. Bioimpedance-assisted placement of a medical device
US8801693B2 (en) 2010-10-29 2014-08-12 C. R. Bard, Inc. Bioimpedance-assisted placement of a medical device
USD754357S1 (en) 2011-08-09 2016-04-19 C. R. Bard, Inc. Ultrasound probe head
USD699359S1 (en) 2011-08-09 2014-02-11 C. R. Bard, Inc. Ultrasound probe head
US9211107B2 (en) 2011-11-07 2015-12-15 C. R. Bard, Inc. Ruggedized ultrasound hydrogel insert
US9839372B2 (en) 2014-02-06 2017-12-12 C. R. Bard, Inc. Systems and methods for guidance and placement of an intravascular device

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