CA2051152A1 - Less position dependent volumetric flow measuring apparatus, catheter for use therein, and method - Google Patents
Less position dependent volumetric flow measuring apparatus, catheter for use therein, and methodInfo
- Publication number
- CA2051152A1 CA2051152A1 CA 2051152 CA2051152A CA2051152A1 CA 2051152 A1 CA2051152 A1 CA 2051152A1 CA 2051152 CA2051152 CA 2051152 CA 2051152 A CA2051152 A CA 2051152A CA 2051152 A1 CA2051152 A1 CA 2051152A1
- Authority
- CA
- Canada
- Prior art keywords
- catheter
- transducers
- vessel
- tubular member
- transducer
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
Links
- 238000000034 method Methods 0.000 title claims description 26
- 230000001419 dependent effect Effects 0.000 title description 9
- 238000005259 measurement Methods 0.000 claims abstract description 32
- 239000007788 liquid Substances 0.000 claims abstract description 10
- 210000001147 pulmonary artery Anatomy 0.000 claims description 20
- 238000004891 communication Methods 0.000 claims description 10
- 239000012530 fluid Substances 0.000 claims description 5
- 229910001220 stainless steel Inorganic materials 0.000 claims description 4
- 239000010935 stainless steel Substances 0.000 claims description 4
- 210000005245 right atrium Anatomy 0.000 claims description 3
- 210000005241 right ventricle Anatomy 0.000 claims description 3
- 238000005070 sampling Methods 0.000 claims 2
- 230000000153 supplemental effect Effects 0.000 claims 2
- 230000003247 decreasing effect Effects 0.000 claims 1
- 239000007787 solid Substances 0.000 claims 1
- 230000000747 cardiac effect Effects 0.000 description 7
- 240000004543 Vicia ervilia Species 0.000 description 5
- 230000017531 blood circulation Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000012544 monitoring process Methods 0.000 description 5
- 230000001746 atrial effect Effects 0.000 description 4
- 239000004020 conductor Substances 0.000 description 3
- 238000003780 insertion Methods 0.000 description 3
- 230000037431 insertion Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 239000004033 plastic Substances 0.000 description 3
- 229910000679 solder Inorganic materials 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 230000004872 arterial blood pressure Effects 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 230000005465 channeling Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 230000008030 elimination Effects 0.000 description 2
- 238000003379 elimination reaction Methods 0.000 description 2
- 210000004731 jugular vein Anatomy 0.000 description 2
- 239000004816 latex Substances 0.000 description 2
- 229920000126 latex Polymers 0.000 description 2
- 230000002685 pulmonary effect Effects 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 210000001367 artery Anatomy 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000013131 cardiovascular procedure Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000002788 crimping Methods 0.000 description 1
- 230000002526 effect on cardiovascular system Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 238000005188 flotation Methods 0.000 description 1
- 235000015277 pork Nutrition 0.000 description 1
- 210000003102 pulmonary valve Anatomy 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 210000000591 tricuspid valve Anatomy 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 210000005166 vasculature Anatomy 0.000 description 1
- 230000002861 ventricular Effects 0.000 description 1
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/06—Measuring blood flow
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/02—Detecting, 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
- A61B5/026—Measuring blood flow
- A61B5/0275—Measuring blood flow using tracers, e.g. dye dilution
- A61B5/028—Measuring blood flow using tracers, e.g. dye dilution by thermo-dilution
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/12—Diagnosis using ultrasonic, sonic or infrasonic waves in body cavities or body tracts, e.g. by using catheters
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/44—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device
- A61B8/4444—Constructional features of the ultrasonic, sonic or infrasonic diagnostic device related to the probe
- A61B8/445—Details of catheter construction
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/46—Ultrasonic, sonic or infrasonic diagnostic devices with special arrangements for interfacing with the operator or the patient
- A61B8/461—Displaying means of special interest
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/46—Ultrasonic, sonic or infrasonic diagnostic devices with special arrangements for interfacing with the operator or the patient
- A61B8/467—Ultrasonic, sonic or infrasonic diagnostic devices with special arrangements for interfacing with the operator or the patient characterised by special input means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
- G01F1/663—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters by measuring Doppler frequency shift
Abstract
ABSTRACT OF THE DISCLOSURE
Apparatus for measuring the volumetric flow of a liquid in a vessel having a wall and having an axis extending longitudinally of the vessel parallel to the vessel wall. A flexible catheter is provided which has a longitudinal axis adapted to be disposed in the vessel.
The catheter has first and back sides. First, second, third and fourth transducers are carried by the catheter. The first, second and fourth transducers are disposed on the front side of the catheter and the third transducer is positioned on the back side of the catheter. The second and fourth transducers are spaced apart a predetermined distance. The first, second and third transducers comprise a first set of transducers and the first, third and fourth transducers comprise a second set of transducers. Instrumentation is connected to the first, second, third and fourth transducers. The instrumentation causes the first, second, third and fourth transducers to emit ultrasonic energy beams therefrom. The first transducer is positioned on the catheter to emit an ultrasonic energy beam at an angle with respect to the longitudinal axis of the catheter. The second and third transducers are positioned in the catheter to emit ultrasonic beams extending generally perpendicular to the longitudinal axis of the catheter. The fourth transducer is positioned so that it emits an ultrasonic beam. The instrumentation receives the signals from the first, second, third and fourth transducers and measures the velocity of profile of the flow of liquid in the vessel by Doppler shift and ascertains the diameter of the vessel in the vicinity of the transducers. The instrumentation is capable of ascertaining which of said first and second sets of transducers provides more accurate velocity profile and diameter measurements of the vessel.
Apparatus for measuring the volumetric flow of a liquid in a vessel having a wall and having an axis extending longitudinally of the vessel parallel to the vessel wall. A flexible catheter is provided which has a longitudinal axis adapted to be disposed in the vessel.
The catheter has first and back sides. First, second, third and fourth transducers are carried by the catheter. The first, second and fourth transducers are disposed on the front side of the catheter and the third transducer is positioned on the back side of the catheter. The second and fourth transducers are spaced apart a predetermined distance. The first, second and third transducers comprise a first set of transducers and the first, third and fourth transducers comprise a second set of transducers. Instrumentation is connected to the first, second, third and fourth transducers. The instrumentation causes the first, second, third and fourth transducers to emit ultrasonic energy beams therefrom. The first transducer is positioned on the catheter to emit an ultrasonic energy beam at an angle with respect to the longitudinal axis of the catheter. The second and third transducers are positioned in the catheter to emit ultrasonic beams extending generally perpendicular to the longitudinal axis of the catheter. The fourth transducer is positioned so that it emits an ultrasonic beam. The instrumentation receives the signals from the first, second, third and fourth transducers and measures the velocity of profile of the flow of liquid in the vessel by Doppler shift and ascertains the diameter of the vessel in the vicinity of the transducers. The instrumentation is capable of ascertaining which of said first and second sets of transducers provides more accurate velocity profile and diameter measurements of the vessel.
Description
LESS POSITION DEPENDENT VOLUMETRIC
FLOW MEASURING APPARATUS, CATHETER
FOR USE THEREIN, AND METHOD
This invention relates to a volumetric flow measuring apparatus and catheter ~or use therein which is less position dependent and method.
This is a continuation-in-part o~ application Serial No.
254,317 filed on October 5, 1~88.
In co-pending application Serial No. 254,317 filsd on October 5, 1988, there is disclosed an apparatus and method for continuously measuring volumetric blood flow using multiple transducers. In that application there is disclosed positioning of such a multiple transducer catheter within a vessel such as the main pulmonary artery so as to obtain accurate volumetric flow measurements. During utilizing such a multiple t~ansducer catheter and method, it has been found that certain doctors have had some di~ficulty in ascertaining the correct position for the catheter. In addition, it has been found that even after the catheter has been oorrectly positioned, a~ter a period of time, as for example, in an intensive care unit, movement of the catheter may occur requiring repositioning of the catheter. Since typically attendant nurses are not . : . . ,. : ,. ... . . ... ....... . . .
FLOW MEASURING APPARATUS, CATHETER
FOR USE THEREIN, AND METHOD
This invention relates to a volumetric flow measuring apparatus and catheter ~or use therein which is less position dependent and method.
This is a continuation-in-part o~ application Serial No.
254,317 filed on October 5, 1~88.
In co-pending application Serial No. 254,317 filsd on October 5, 1988, there is disclosed an apparatus and method for continuously measuring volumetric blood flow using multiple transducers. In that application there is disclosed positioning of such a multiple transducer catheter within a vessel such as the main pulmonary artery so as to obtain accurate volumetric flow measurements. During utilizing such a multiple t~ansducer catheter and method, it has been found that certain doctors have had some di~ficulty in ascertaining the correct position for the catheter. In addition, it has been found that even after the catheter has been oorrectly positioned, a~ter a period of time, as for example, in an intensive care unit, movement of the catheter may occur requiring repositioning of the catheter. Since typically attendant nurses are not . : . . ,. : ,. ... . . ... ....... . . .
permitted to reposition the catheter, there is still a need for obtaining accurate volumetric readings until a physician can be summoned. Also, there ~s a need for a catheter to provide accurate volumetric readings for substantial periods of time without the need for repositioning.
Also, in application Serial No. 254,317 filed on October 5, 1988, there is disclosed an apparatus and method for continuously measuring volumetric blood flow which utilizes a catheter having predetermined bends at the distal extremity ~hereof and in which a positioning device is used to alter the shape of the bends prior to insertion of the catheter into the patient. The positioning device is extended to enlarge the angle of the predetermined bend to enable the tip of the catheter to negotiate with an inflated balloon the right atrium, the right ventricle and to the main pulmonary artery and finally out to the right branch of the pulmonary artery.
Thereafter, the positioning device is typically retracted and thereafter acts as a passive element providing some support to the catheter but not in the region of the predetermined bend. It has been found that it is desirable to eliminate the complexity of the catheter to make it easier for the cardiovascular surgeon to utilize it in cardiovascular procedures.
There is therefore a need for a volumetric flow measuring apparatus and method which is less position dependent.
In general, it i~ an object of the present invention to provide a volumetric flow measuring apparatus and method which is less position dependsnt.
Also, in application Serial No. 254,317 filed on October 5, 1988, there is disclosed an apparatus and method for continuously measuring volumetric blood flow which utilizes a catheter having predetermined bends at the distal extremity ~hereof and in which a positioning device is used to alter the shape of the bends prior to insertion of the catheter into the patient. The positioning device is extended to enlarge the angle of the predetermined bend to enable the tip of the catheter to negotiate with an inflated balloon the right atrium, the right ventricle and to the main pulmonary artery and finally out to the right branch of the pulmonary artery.
Thereafter, the positioning device is typically retracted and thereafter acts as a passive element providing some support to the catheter but not in the region of the predetermined bend. It has been found that it is desirable to eliminate the complexity of the catheter to make it easier for the cardiovascular surgeon to utilize it in cardiovascular procedures.
There is therefore a need for a volumetric flow measuring apparatus and method which is less position dependent.
In general, it i~ an object of the present invention to provide a volumetric flow measuring apparatus and method which is less position dependsnt.
3~
Another object of the invention is to provide an apparatus and method of the above character in which redundancy is provided by providing one or more additional transducers.
~nother object of the invention is to provide an apparatus and method of the above character which substantially reduces the need for repositioning of the catheter.
Another object of the invention is to provide a method and apparatus of the above character in which a cath~ter is utilized which eliminate the need for a movable guide wlre .
Another object of the present invention is to provide a catheter which utilizes an elongate wire in a fixed position which is used to 6tiffsn certain portions of the catheter.
Another object of the invention i8 to provide an apparatus and method of the above character in which real time feedback is provided to aid in the positioning of the catheter.
Another object of the invention is to provide an apparatus and method of the above character in which error criteria are defined such that gradual ~ignal degradation or improvement i6 displayed continuously to aid in placement of the catheter by the physician and at the same time optimizing a displayed figure of merit for the received signals.
- . . . ~ ..
:. : -. .
.. , ~ . ~ .. . .
. ,: , ... .. .
Another object of the invention is to provide an apparatus and method of the above character in which redundancy is provided by providing one or more additional transducers.
~nother object of the invention is to provide an apparatus and method of the above character which substantially reduces the need for repositioning of the catheter.
Another object of the invention is to provide a method and apparatus of the above character in which a cath~ter is utilized which eliminate the need for a movable guide wlre .
Another object of the present invention is to provide a catheter which utilizes an elongate wire in a fixed position which is used to 6tiffsn certain portions of the catheter.
Another object of the invention i8 to provide an apparatus and method of the above character in which real time feedback is provided to aid in the positioning of the catheter.
Another object of the invention is to provide an apparatus and method of the above character in which error criteria are defined such that gradual ~ignal degradation or improvement i6 displayed continuously to aid in placement of the catheter by the physician and at the same time optimizing a displayed figure of merit for the received signals.
- . . . ~ ..
:. : -. .
.. , ~ . ~ .. . .
. ,: , ... .. .
-4- ~c,'~
Another ob;ect of the invention i~ to provide an apparatus and method o~ the a~ovs charaatsx in which the optimum tran~ducer configuration is ~elected.
Another ob;ect of the inven~ion ls to provide an apparatus and mekhod of the above character in which real time flow measurements are displayed.
Additional objects and features of the invention will appear from the following description in which the preferred embodiment is set forth in detail in conjunction with the accompanying drawings.
Figure l is an isometric view of an apparatus for continuously measuring volumetric blood flow incorporating the present invention.
Figure 2 is a cross sectional view taken along the line 2-2 of Figure l.
Figure 3 is a schematic illustration of a catheter of the present invention disposed within a vessel for obtaining a volumetric flow rate utilizing four transducers on the catheter.
Figures 4A, 4B and 4C are cross sectional views of a human heart showing three different positions of the catheter of the present invention in the pulmonary artery of the heart.
Figures 5A, 5B, 5C and 5D are schematic illustrations of various transduaer arrangement~ on a catheter of the pre~ent invention.
Another ob;ect of the invention i~ to provide an apparatus and method o~ the a~ovs charaatsx in which the optimum tran~ducer configuration is ~elected.
Another ob;ect of the inven~ion ls to provide an apparatus and mekhod of the above character in which real time flow measurements are displayed.
Additional objects and features of the invention will appear from the following description in which the preferred embodiment is set forth in detail in conjunction with the accompanying drawings.
Figure l is an isometric view of an apparatus for continuously measuring volumetric blood flow incorporating the present invention.
Figure 2 is a cross sectional view taken along the line 2-2 of Figure l.
Figure 3 is a schematic illustration of a catheter of the present invention disposed within a vessel for obtaining a volumetric flow rate utilizing four transducers on the catheter.
Figures 4A, 4B and 4C are cross sectional views of a human heart showing three different positions of the catheter of the present invention in the pulmonary artery of the heart.
Figures 5A, 5B, 5C and 5D are schematic illustrations of various transduaer arrangement~ on a catheter of the pre~ent invention.
-5~
Figure 6 is a plan view of an alkernative embodiment of an ultrasonic pulmonary artery ca~heter which incorporates the pre~ent invention and eliminates the need for a movable guide wire~
Figure 7 i9 an enlarged detail view of the fixed wire used in the catheter shown in Figure 6.
In general, the apparatus is for measuring volumetric flow of liquid in a vessel which has a wall and an axis extending longitudinally o~ the vessel parallel to the vessel wall. A flexible catheter which has a longitudinal axis is provided and i6 adapted to be disposed in the vessel. First, ~econd and third ultrasonic transducers are carried by tha catheter on one side of the catheter and are spaced apart longitudinally of the catheter. The second and third transducars are spaced apart a predetermined distance.
~he first and second transducers comprise one set of transducers and the first and third transducers comprising another set of transducers. Instrumentation means is provided which iæ connected to the first, second and third transducers for causing them to emit ultrasonic energy beams therefrom. The first of the ultrasonic transducers is positioned on the catheter to emit an ultrasonic energy beam at an angle with respect to the longitudinal axis of the catheter and the second and third transducers are positioned on ~he catheter to emi~ ultrasonic beams extending generally perpendicular to the longitudinal axis of the catheter. The instrumentation means provided includes means connecting the first, second and third transducers whereby the first transducer mea~ures the velocity profile of the flow of the liguid in the vessel by Doppler shift mea6urements and the second and khird transducers are . , , ;,:, . ~ ; . :, , .
--6-- 2 ~
used for measuring the velocity profile of the flow of the liquid in the vessel by Doppler shi~t measurements and at least a portion of the diame~er o~ the vessel at the location that the transducer is positioned on the catheter. The instrumentation means also includes means for ascertaining which o~ the first and second sets, or all, of ultrasonic tranæducers provides the optimal velocity profile and diameter measurements. The instrumentation means also includes means for sensing an error condition when an optimal measurement i5 not available from the catheter as it is positioned.
~ore specifically, the apparatus and method for continuously measuring volumetric blood flow using multiple transducers is shown in Figure 1. As shown therein the apparatus consi~ts of a control console 11 and a catheter 12 which is connected to the control console 11. The catheter 12 consists of a flexible elongate member 13 formed o~ suitable material such as plastic. A cross-sectional view of the elongate member 13 is shown in Figure 2 and as ~hown therein, the flexible elongate member 13 is provided with a plurality of lumens 16, 17, 18, 19, 21, 22 and 23 for a total of 7 lumens. As shown, the lumens are of various sizes and perform different functions. For example, lumen 16 is utilized for providing pressure monitoring, also serves as a possible injectate lumen and it accommodates the front distal, intermediate and proximal transducers T4, T2 and Tl. Lumen 17 is provided for the wires 24, 26, 27, 28 and 30a and 30b for the ~ront proximal, intermediate and distal transducers T4, T2 and Tl respectively. Lumen 18 is provided for the thermistor and the thermistor wires 31 and 32. Lumen 19 is utilized for providing pressure monitoring and ~erves as a possible injectate lumen. Lumen 21 is provided for ,, --~ ~ " ',~ 1~ r~
a guide wire 29 and al~o ~erve~ as a balloon ln~lationand de~lation lumen. Lumen 22 i5 used to provide pressure monikoring and also ~erves a~ a passible in~ectate lumen. Lumen 22 generally indiaate~ right ventricular or main pulmonary artery pressure. Lumen 23 accommodates the wires 33 and 34 ~or the back transducer T3.
In the preferred embodiment, lumen 16 provides right arterial pressure monitoring and serves as an injectate lumen. Lumen 19 provides distal or pulmonary wedge pressure monitoring. ~umen 22 provides pressure monitoring in the area of the transducers, so as to indicate their position and serves as an injectate lumen.
It has been found that these seven lumens can be provided in ~lexible plastic tubing 13 having an outside diameter of 0.098 inches plus or minus .003 inches. The outside circular wall 36 has a minimum thickness of approximately 0,007 inches. The septa 37 dividlng the lumens ~hould have minimum thicknesses of approximataly 0.004 inches.
As can be seen ~rom Figure 1, the di~tal extremity or tip 41 of the elongate member 13 is generally U-shaped.
The flexible elongate memher 13 is provided with a substantially straight flexible portion 13a having a length of approximately 110 centimeters. The U-shaped tip 41 configuration has a length of approximately 15 c~ntimeter~ for a total length o~ la5 centimeters ~or the elongate member 13. The ~lexible elongate member 13 i~ provided with another relatively straight p~rtion 13b extending beyond an approximately 90 bend 43. It also i~ provided with another generally straight portion , , , 13c extending beyond a more gently curved approximately 60~ bend 44.
~n inflatable flotation balloon 46 i~ mounked on the distal extremity of the portion 13c by suitable means such as an adhesive. The balloon is formed of a suitable material such as latex and can be inflated and deflated by a fluid passing through an inflation and deflation port 47 which i6 in communication with the balloon inflation lumen 21. The balloon 46 will take a generally spherical configuration as shown in dotted lines when inflated and can be in~lated to a suitable diameter as, for example, 10 to 14 millimeters. As can be seen the portion 13c extends through the balloon and is provided with a distal pressure port 48 which is in communication with the lumen 19.
A thermistor 51 of a conventional construction is mounted in the portion 13c proximal of the balloon 46 intermediate o~ the bend 44 and the balloon 46. It is mounted in the space occupied by the lumen 1~. The thermistor 51 is connected to conductors 31 and 32 which extend through the lumen 13.
Additional ports are provided in the catheter 12 and include a positioning port 54 which is in communication with the lumen 22 and a right atrial pressure port and injectate port 56 which is in communication with the lumen 16. Both of the ports 54 and 56 are located near the distal extremity of the flexible elongate member 13 with the port 54 being located from 1 to 3 centimeters from the proximal end of the bend 43 and the port 56 being located approximately 18 centimeters from khe port 54.
.
, The proximal extremity of the elongate member 13 is connected to a plurality oP ~ittings through a manifold molding 96 as shown in Figure 1. Thus there i5 provided an elongate flexible member 61 which i~ provided with a Luer-type ~itting 62. ~he ~lexible elongate tubular member 61 is aonnected to the right atrial pre~ure lumen 16. Another elongate flexible tubular member 63 is provided with a Luer-type fitting 64 and is connected to the distal pressure lumen 19. Another ~lexible elongate member 66 is connected ~o the balloon inflation lumen 21. A two arm adapter 67 is mounted on the tubular member 66 that is connected to a 6top cock 71 which is provided with a handle 72 and a Luer-type fitting 73. A syringe 74 of a conventional type is provided which carries a fluid of a suitable type such as carbon dioxide which can be used for inflating and deflating the balloon 46. The adapter 67 is also provided with a central arm 76.
The guide wire 29 serves as a positioning and straightening device and extends through the lumen 21 and has a suitable diameter such as .012 inches. The guide wire 29 is formed of a ~uitable material such as stainless steel and is attached to a relatively straight piece o~ hypodermic tube 79 having a suitable diameter ~5 such as 0.042 inches and is also formed of a suitable material such as stainless steel. The tube 79 has a length such that it extends approximately the entire length o~ the flexible elongate member 66. A knob 81 i6 sscured to the proximal extremity of the tube 79 and is u~ed for advancing and retracting the guide wire 29.
The guide wire 29 has a length so that when the knob i6 pushed forward into the central arm 76, the guide wire 29 extends through to the distal extremity or tip 41 of the catheter 12 to ~ubstantially straighten the same to . ~ - ; .
, . : ....
facilitate insertion o~ the catheter 12 into the vessel of the human body and al~o to ~acilitate advancement o~
the same as the inflated balloon 46 is utilized to advance the catheter as hereina~ter de~cribed. A raised section such as solder joint or other means 82 on the tube 79 serves as a stop to prevent retraction of the tube 79 through a removable cap 83 carried by the central arm 76. The proximal extremity of the wire 29 and the tube 79 are joined together by conventional means such as solder or by crimping.
Another flexible elongate element 86 with a Luer-type fitting 87 is provided which is in communication with the positioning pressure lumen 22. Another flexible elongate tubular member ~8 is in communication with the lumen 18. It is provided with a thermodilution connector 89 of a conventional type. Another flexible elongate member 91 is provided which has wires extending therethrough which are connected to the back transducer provided in the lumen 23 and the front transducer wires provided in lumen 17. The elongate member 91 is connected to a connect~r 92 which is connected to all of the wires extending through the elongate member 91.
A manifold molding 96 is provided around the proximal extremity of the flexible elongate member 13 and the distal extremities of the flexible elongate members 61, 63, 66, 86, 88 and 91. A strain relief and reinforcing member 97 formed of a suitable materia~ such as rubber extends out of the molding 96 and covers the proximal extremity 42 of the flexible elongate element 13.
The connector 92 plugs into it~ corresponding connector 101 which is at the end o~ cahle 102 that extends into the front panel 103 of the control console 11. As shown in Figure 1, the control console includes a knob 104 ; ~, , ' , . ,. ~ ' ':
.... , ,-- . .. , i . :
' .Y '.S
provided on the front panel 103 which can be utilized for setting the alarm settings of the cardiac output limits and the diameter limits o~ the appar~kus. A
"power on" push button 106 is provided as well as an alarm muting push button 107. In addiklon, push buttons 108 and 109 can be provided for setting "alarm on", and "high" and "low~ alarm limits for the cardiac output.
Similarly, push buttons 111 and 112 can be provided for setting "alarm on", and t'low" and ~high~ alarm limits for the diameter measurement. A graphic display 116 is provided for displaying instantaneous flow waveforms, flow trends or velocity profiles. Mode push buttons 117 are provided for selecting either a "monitor" or "insert" mode. A digital readout 118 is provided for displaying the cardiac output in liters per minute with push buttons 119 and 121 giving the capabilities to provide the mean cardiac and the peak cardiac outputs.
In addition, a digital display 122 is provided for giving a readout of measured parameters such as the diameter of the vessel being monitored in millimeters, stroke volume or a cardiac index. Vertical LCD bars display 123 is provided adjacent the display 116. The bars display 123 by their heights give an indication of the validity of the acoustic information being processed by the control console 11 and thereby give an indication of the efficacy of position of the catheter in making correct velocity and volumetric flow measurements in the vessel in which it is positioned.
In accordance with the present invention, to obtain the 30 type of information which is provided by the console 11, at least four ultrasonic transducers are carri.ed by the catheter 12. Front and back transducers are provided as her~inafter de~cribed. The front transducers typically are mounted within the recess provided by the :, . . . .
- .' ~
::
, : , - , ' ' ~- :
-12~ ~ f~ 3 i~
lumen 16 wherea~ the back transducere are provided in the lumen 23 which i~ diametrically opposite the lumen 16. The distal extremity bends 43 and 44 are formed within the plane which includes the longikudinal axis of the catheter 12 and a line passing diametrically through the catheter and through the middle of the front and back transducer lumens 16 and 23 respectively. This is necessary to orient the transducer beams such that each lies substantially within a single plane which includes the longitudinal axis of the main pulmonary artery when the catheter's distal extremity 13c is positioned downstream in one of the smaller branches of the right pulmonary artery. This beam positioning is essential to obtain accurate diameter and velocity profile measurements for calculating volumetric blood flow or cardiac output.
In Figures 4A, 4B and 4C, the catheter 12 is shown positioned within a human heart. The introduckion of the catheter 12 through the jugular vein of the patien~
is a technique which is generally well known to those skilled in the art. In order to facilitate introduction, the guide wire 29 is advanced to its extreme distal position by operation of the knob 81 to straighten the distal extremity or tip 41 of the catheter 12 to facilitate introduction of the catheter into the jugular vein o~ the patient. The catheter 12 as showrl in Figures 4A, 4B and 4C passes into the heaxt 161 through the venous port 162 of the superior vena cavae 163, through the right atrium 164, and ~hen through the tricuspid valve lS6, the right ventricle 167, through the pulmonary valve 168, through the main pulmonary artery 1~9 and inko the right pulmonary artery branch 171 and then wedglng downstream ln one of the secondary branches leading from the right pulmonary -13- ~J~
artery branch with the tip o~ the catheter having the balloon thereon being disposed in that branch. In the course of inserting the catheter, i~s location can be monitored by observing the pressure waveforms which are guite distinct from one another in the di~ferent parts of the circulatory sy6tem. Adeguate velocity and diameter determinations can generally be made with the transducers positioned in the region between pulmonic valve 168 and below bifurcation 172.
In the arrangement shown in ~igures l and 3, it can be seen that first, ~econd and fourth ultrasonic transducers Tl, T2 and T4 are carried by the catheter on the front side of the catheter and are spaced longitudinally o~ the catheter 12. The second and fourth transducers or, in other words, the transducers T2 and T4 are spaced apart a predetermined distance.
A third transducer T3 is provided on the back 6ide of the catheter 12 oppo6ite the transducers Tl, T2 and T4 and faces in a direction which is 180 opposed to the direction in which the transducers T2 and T4 face. The transducer T3 may not be necessary when the catheter is immediately adjacent a wall of the vessel. As hereinafter described, the first and second transducer6, transd~cers Tl and T2 serve a~ one set o~ transducers in conjunction with the third transducer T3 and the first and fourth transducers Tl and T4 form another set of transducer~ in conjunction with the third tranæducer T3. ~he control console ll ~erves to supply electrical signals to the transducers through the connecting wires hereinbefore described to cause the transducers to emit ultrasonic energy beams as indicated by the rays Bl, B2, B3 and B4 æhown in Figure 3. The first ultrasonic transducer Tl is positioned on the catheter 50 that it emits an ultrasonic energy beam Bl which is at an angle .
~1 with respact to the longitudinal axis of the catheter 12. The transducers T2, T3 and T4 emit ultrasonic beams B2, B3 and B4 at angles ~2, e 3 and ~4 which are generally perpendicular to the longitudinal axis of the catheter 12. The beams B2, B3 and B4 are directed at angles which are substantially 90 with respect to the longitu~inal axis of the catheter 12. The beam B3 is directed in a direction which is 180 or opposite to that of the beams B2 and B4.
In conjunction with the instrumentation means provided by the control console 11, the first transducer Tl measures the velocity profile of the liquid in the vessel 181 by Doppler shift measurements. The second and fourth transducers T2 and T4 are also used for measuring ~he velocity profile o~ the flow of the liquid in the vessel by Doppler shift measurements and at least a portio~ of the diameter of the vessel at the location that the transducer is positioned on the catheter. The third transducer T3 measures at least a portion of the diameter of the vessel at the location that the transducer is positioned on the catheter. The instrumentation means provided by the control console 11 also includes means for ascertaining which of the first and second sets, or all, of ultrasonic transducers provides optimal velocity pro~ile and diameter measuremen~s.
In the po6ition of the catheter 12, ~hown in Figure 4A, the catheter 12 either becau~e o~ the vasculature of the heart or the longitudinal position of the catheter in the pulmonary artery or vessel in the heart has both o~
the transducers T2 and T4 on the front side of the catheter in good posi~ions to receive the desired information to provide accurate velocity and volumetric A-53061~HCH
' '''"':
-15~ f'~"
blovd flow through ~he vessel. The transducers T2 and T4 are both ln optimum po~itions wikhin the pulmonary artery to make accura~e mea~urement~. In this ~ituation, instrumentatlon 11 w~11 u~e either transducers Tl, T2, and T3 as a ~et, or tran~ducers Tl, T4, and T3 a6 a set. Or, it may u~e all four transducers Tl, T2, T3, and T4 as a set.
In the position of the ca~heter 12, as ~hown in Figure 4B, there is depicted a 6ituation in which the pulmonary artery ie too 6hort in comparison to the ~pacing between the catheter transducers T2 and T4 or the catheter 12 is somewhat proximal to the position where it should be located because the transducer T4 is in a region of or below the pulmonic valve 168 in the heart. For that reason the information supplied by the transducer T4 is inaccurate or inappropriate. However, the transducer T2 is still in a good position and therefore the instrumentation ll will ascertain that this information is appropriate information and will supply the appropriate measurements utilizing transducers Tl, T2 and T3 as the set of transducers, rather than the transducers Tl, T4 and T3 as the 6et of transducers.
In Figure 4C there is depicted a situation in which the transducer T2 may not provide good information with the ~ituation being that the catheter 12 has been pushed too far di6tally or the pulmonary artery is quite long in comparison to the spacing between the tran~ducers T2 and T4. In ~uch a ~ituation the in6trumentation ll will select the transduc~rs Tl, T3 and T4 as belng the transducers to be utllized rather than the transducers Tl, T2 and T3. The diameter transducers are used two at a time to measure diameter when the catheter 12 i~
not immediately adjacent a wall of the ve~sel. Thue, , ~ . . . ~ ~ , . . , .; . :: .
- . . : . :: .
- :: : . . : : . : :
: . : . . , : :
-16- 7 J~
eithex T2 and T3 or T3 and T4 are used to measure the diameter of the vessel.
I~ the catheter 12 is positioned in such a manner that neither o~ the transducer~ T2 and T4 in conjunction with transducers Tl and T3 can provide good signals to provide accurate velocity profile and volumetric flow measurements, this situation i8 sensed by the instrumentation or control console 11, and an error signal will be provided on the control console 11 which will appear on the digital di6play. However, it can be seen that an error ~ignal will only be generated by the control console 11 when neither the transducers T2 and T4 in conjunction with transducers Tl and T3 will provide a good measurement. Becauss of this factor, the position of the catheter 12 is much less position dependent and thus will give a range of accurate readings in a wider range along the longitudinal axis of the catheter 12 than would be possible with a single transducer such as transducer T2 or transducer T4.
It should be appreciated that if desired the fourth transducer T4 rather than being a diameter transducer can be positioned at an angle similar to transducer Tl to be a velocity transducer (see Fig. 5A). This would make it possible to select either of the velocity transducers Tl or T4 using always the two diameter transducers T2 and T3.
It should also be appreciated that if the ~ourth transducer T4 rather than being primarily a diameter transducer iB instead a velocity transducer eimilar to Tl, its beam direction can be opposite to that of Tl.
That is if beam Bl points upstream, beam B4 would point downstxeam, as in Fig. 5B.
, . . . . . . . .
It should also be appreciated that transducers T1, T2, T3 and T4 can be in other order~ and directions, depending on the algorithms used to analyze the velocity and diameter in~ormation and per~orm the ~low calculations. As examples, Tl, T3 and T4 could be primarily for diameter~ measurements, with T2 being used ~or velocity measurements (see Fig. 5c). Or, T3 and T4 could be used primarily for diameter measurements with Tl and T2 being for velocity measurements (See Fig. 5D).
In the past, a pressure psrt has been located adjacent to the transducers and this pressure port has been utilized as a key for positioning the catheter.
However, with respect to the present catheter, this pressure pork is merely used as a reference point when the positioning of the catheter has been accomplished more effectively by utili7ing error criteria to determine the proper position of the catheter. This can be readily accomplished by utilizing error criteria in an algorithm incorporated into so~tware implemented within the control console 11 to establish whether or not the diameter and the velocity ~ignals being received are in ~act accurate measurements. Appropriate data would be incorporated into the algorithm by channeling the algorithm. By channeling the algorikhm data parallel with the signals being received from the transducer, the control console 11 can be utilized to detect errors in the input signals. Utilizing such information, appropriate instruction6 can be provided on the control console 11 to facilitate positioning of the catheter 12 in the vessel. For example, instructions can be given to advance or retract the catheter to improve the signal~ being received.
. ...
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- .: .:
: : :
From the foregoing, it can be seen that there has been provided a volumetric flow measuring apparatus and method which is less position dependent. Because of the use of an additional transducer or transducers, the need for repositioning of the catheter is substantially reduced. Real time feedback i8 provided to aid in positioning of the catheter. Error criteria are defined such that gradual signal degradation or improvement is displayed continuously to aid in placement of the catheter by the physician while at the same time optimizing a displayed figure of merit for the received signals from the transducers.
It also has been found that in order to make the volumetric flow measuring apparatus and method less dependent upon positioning of the catheter that it is desirable to provide a catheter which does not utilize a movable guidewire. Such a catheter 201 is shown in Figures 6 and 7. The ~atheter 201 shown therein is adapted to be substituted for the catheter 12 and is adapted to be connected to the control console 11 shown in Figure 1. This catheter 201 in many respects is very similar to the catheter 12 shown in Figure 1 with the exception that the guidewire 79 utilized in the catheter a~sembly shown in Figure 1 is eliminated. Also a gentle substantially J-shaped bend is provided in the distal extremity of the catheter 201 rather than the generally U-shaped bend provided in Figure 1.
The catheter 201 6hown in Figure 6 consi~ts of a flexible elongate member 202 formed of plastic. A cross section like Figure 2 taken of the flexible elongate member in the position shown in Figure 1 would provide a similar cross section in which a total of sev2n lumens are provided in the flexible elongate member 2~2.
: . . . : , . , " - . : . , . .
.: ~; ~ . : : , ~ .
, : . ~ ; . . . .
, . . , " ~ ~ , The flexible elongate member 202 is provided with a relatively straigh~ flexible portion 202a having a suitable length as for example approximately 110 cm up to a bend 203 of approximately 15 to 20 after which there is provided another flexible relatively straight portion 202b up to a bend 204 of another ~mall angle as fvr example 15 to 20 after which there is provided another flexible relatively straight portion 202c extending to the distal extremity of the catheter 201.
Thus, the bend 203 forms an angle of approximately 165 to 160 and bend 204 forms an angle of approximately 165 to 160. Thus it can be sePn that the bend 203 and 204 in the distal extremity of the catheter 201 provide a very gentle curvature which represents a substantially modified J-bend. An inflatable latex balloon 206 is provided on the distal extremity of the flexible elongate member 202 and is adapted to he inflated and deflated through a port 207.
A thermistor 211 is mounted in the portion 202c adjacent the bend 204. Transistors T1, T2, and T4 are mounted on the front side of the flexible elongate member 202 proximal of the bend 203 and the transistor T3 is provided on the backside of the member 202 opposite and between the transducers T2 and T4. However, it should be appreciated that the four transducers can be arranged in any of the manners heretofore desoribed. A main pulmonary artery port 212 is provided in the ~lexible elongate member 202 slightly proximal of the transistor T4 and a right atrial port 213 is provided proximal of the port 212.
Markers 216 visible to the human eye of a conventional type are provid2d on the exterior surface of the flexible elongate member 202 and are spaced . .
-, , , ' '.~',, . . . ' : ~
~ - ; . - . . , ~ .
-20- , ~ 5 ~ s longitudinally thereof. The markers 216 ~erve to indicate to the ~urgeon how far the ~atheter 201 has been introduced into the patient.
The proximal extremity of the flexible elongate member 202 is connected through a manifold 221 to a plurality of flexible elongate members 222, 223, 224, 226, 227 and 228. The flexible elongate member 222 is connected to the distal pressure lumen and is provided with a Luer adap~er 231 at its proximal extremi~y. The flexible elongate member 223 carries the conductors provided in the flexible elongate member 202 connQcted to the devices in the catheter. The conductors in the elongate member 223 are connected to an electrical connector 232 at the proximal extremity of the flexible elongate member 223. The flexible elongate member 224 is provided with a Luer adapter 233 at its proximal extremity. The flexible elongate member 226 is provided with an electrical connector 234 adapted to be connected to a conventional thermodilution console (not shown).
The flexible elongate member 227 is connected to the balloon inflation lumen and is provided with a stop cock 236 which is secured to the flexible elongate member 227 with an adapter 237. The stop cock 236 i6 provided with a Luer type ~itting 238 and a handle 239. The flexible elongate member 228 is connected to the right atrial pressure lumen and is provided with a Luer adapker 240.
Suitable means is provided for giving additional stif~ne6s to the rlexible elongate member 202 which i6 just short of the pre-~ormed bend 03 to provide support and additional rigidity to the catheter throughout substan~ially i~e entire length except in ~he region of the pre-formed bend 203 and beyond to the distal extremity of the catheter. The predetermined bends 203 --2 ~ , !i J
and 204 have been provid~d in the flexible elongate member 202 to provide stability ~or the catheter 201 when the catheter 201 i8 positioned in the pulmonary artery. One means ~or providing thi~ additional rigidity and 6tiPfness in the flPxible elongate member 202 is obtained by utilizing a flexible elongate element 241 in the form of a wire of a suitable mat2rial such as stainless steel. The wire 241 has a length so that it extends substan~ially the entire length of the flexible elongate member 202. Its proximal extremity 241a has a suitable diameter such as .014" which diameter continues ~or a suitable distance as ~or example 70 cm. The wire 241 is then taper ground to a diameter of .012" to provide a portion 241b that extend6 for approximately 20 additional centimeters. Another taper grind then reduces the diameter of the wire 241 to .009" to provide a portion 241c which extends for approximately another 20 centimeters to a region adjacent the transducers Tl to T2, T3 and T4 and in the region of these transducers a portion 241d ie provided on the wire 241 which has a larger diameter of .014" for a distance of 2 to 3 centimeters. The wire portion 241d serves to provide increased stif~ness in the region of the catheter 201. The distal extremity of the wire 241 is provided with a portion 241e which has a continuous taper in which the diameter o~ the wire is reduced ~rom . 014" to .0025" to give additional flexibility to the distal extremity of the wire 241. A coil spring 242 is mounted on the wire 241 by having the tapered portion 241e extend into the coil 242 and be secured thereto by suitable means such as solder. The spring 242 is formed o~ a suitable material such as .002" diameter stainle~s steel wire. The spring has a suitable outside diameter as for example .014" and a length of approximately 2 cm.
The wire 241 with the spring 242 i6 positioned so the .; .
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spring 242 is just short o~ the bend 203. This makes it possible for the distal extremity o~ the catheter 11 to have good flexibility so that it can be floated into the desired position upon inflation of the balloon 206.
At the same time, wire 241 provides additional rigidity to the catheter 201 to facilitate its insertion into ths vessel of the patient.
The proximate extremity of the wire ~41 is provided with a right angle hook portion 241f which is positioned in a hole 244 in the adapter 237 and is retained therein by the stopcock 236 (see Figure 7).
The use of the catheter 201 in the volumetric flow measuring apparatus shown in Figure 1 is very similar to that hereinbefore described in conjunction with the apparatu~ shown in Figure 1. However, it ha~ been ~ound that the catheter 201 makes the catheter less position dependent because the elimination of the movable wire removes another variable in the positioning of the catheter in a desired position within the heart of the patient. This is true because after removal o~ the movable wire from the distal extremity of the catheter, the distal extremity of the catheter has a different flexibility than when the guidewire was positioned in the distal extremity making it more difficult for the instrumentation 11 to ascertain whether or not the catheter 12 has been properly positioned in the heart.
With the use of the fixed wire which only extends up to the bend 203, the flexibility of the distal extremity of the catheter 201 remains constant. The fixed wire 241 provides additional rigidity throughout the remainder of the catheter while providing the desired transitions in flexibility in the regions leading up to the portions of the catheter carrying the transducers , .. . : ~, , ~ . . ;
~ ~ r~
Tl, T2, T3 and T4 while still providing the desired rigidity within the catheter at that region. The spring 242 provides graduated transi~ion at the distal extremity of the wire 241 and provides a r~l~tively blunt end so that the wire 2~1 will not puncture the flexible elongate element 202. Alternatively if desired the spring 242 can be eliminated and a blunt end can be formed on the end of the wire 241 ~or a similar purpose.
The relatively small angle preformed bends 203 and 204 provided in the distal extremity o~ the catheter 201 make it possible for the catheter 201 to negotiate the vessels of the patient and make it possible to facilitate positioning the distal extremity of the catheter in the appropriate position in the heart to thereby properly position the transducers Tl through T4.
The bends 203 and 204 also provide the necessary stability for the distal extremity of the catheter during the time that measurements are being made by the instrumentation console ll from information supplied by the transducers Tl through T4.
From the foregoing it can be seen that the catheter which is shown in Figures 6 and 7 can be utilized in the volumetric flow measuring apparatus and method heretofore described to provide a less position dependent apparatus and met~od. The elimination of the movable wire eliminates one additional variable ~rom the system. Thls makes it possible to more accurately predict when the catheter has been properly positioned in the heart to make accurate volumetric ~low measurement~.
.
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, .
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Figure 6 is a plan view of an alkernative embodiment of an ultrasonic pulmonary artery ca~heter which incorporates the pre~ent invention and eliminates the need for a movable guide wire~
Figure 7 i9 an enlarged detail view of the fixed wire used in the catheter shown in Figure 6.
In general, the apparatus is for measuring volumetric flow of liquid in a vessel which has a wall and an axis extending longitudinally o~ the vessel parallel to the vessel wall. A flexible catheter which has a longitudinal axis is provided and i6 adapted to be disposed in the vessel. First, ~econd and third ultrasonic transducers are carried by tha catheter on one side of the catheter and are spaced apart longitudinally of the catheter. The second and third transducars are spaced apart a predetermined distance.
~he first and second transducers comprise one set of transducers and the first and third transducers comprising another set of transducers. Instrumentation means is provided which iæ connected to the first, second and third transducers for causing them to emit ultrasonic energy beams therefrom. The first of the ultrasonic transducers is positioned on the catheter to emit an ultrasonic energy beam at an angle with respect to the longitudinal axis of the catheter and the second and third transducers are positioned on ~he catheter to emi~ ultrasonic beams extending generally perpendicular to the longitudinal axis of the catheter. The instrumentation means provided includes means connecting the first, second and third transducers whereby the first transducer mea~ures the velocity profile of the flow of the liguid in the vessel by Doppler shift mea6urements and the second and khird transducers are . , , ;,:, . ~ ; . :, , .
--6-- 2 ~
used for measuring the velocity profile of the flow of the liquid in the vessel by Doppler shi~t measurements and at least a portion of the diame~er o~ the vessel at the location that the transducer is positioned on the catheter. The instrumentation means also includes means for ascertaining which o~ the first and second sets, or all, of ultrasonic tranæducers provides the optimal velocity profile and diameter measurements. The instrumentation means also includes means for sensing an error condition when an optimal measurement i5 not available from the catheter as it is positioned.
~ore specifically, the apparatus and method for continuously measuring volumetric blood flow using multiple transducers is shown in Figure 1. As shown therein the apparatus consi~ts of a control console 11 and a catheter 12 which is connected to the control console 11. The catheter 12 consists of a flexible elongate member 13 formed o~ suitable material such as plastic. A cross-sectional view of the elongate member 13 is shown in Figure 2 and as ~hown therein, the flexible elongate member 13 is provided with a plurality of lumens 16, 17, 18, 19, 21, 22 and 23 for a total of 7 lumens. As shown, the lumens are of various sizes and perform different functions. For example, lumen 16 is utilized for providing pressure monitoring, also serves as a possible injectate lumen and it accommodates the front distal, intermediate and proximal transducers T4, T2 and Tl. Lumen 17 is provided for the wires 24, 26, 27, 28 and 30a and 30b for the ~ront proximal, intermediate and distal transducers T4, T2 and Tl respectively. Lumen 18 is provided for the thermistor and the thermistor wires 31 and 32. Lumen 19 is utilized for providing pressure monitoring and ~erves as a possible injectate lumen. Lumen 21 is provided for ,, --~ ~ " ',~ 1~ r~
a guide wire 29 and al~o ~erve~ as a balloon ln~lationand de~lation lumen. Lumen 22 i5 used to provide pressure monikoring and also ~erves a~ a passible in~ectate lumen. Lumen 22 generally indiaate~ right ventricular or main pulmonary artery pressure. Lumen 23 accommodates the wires 33 and 34 ~or the back transducer T3.
In the preferred embodiment, lumen 16 provides right arterial pressure monitoring and serves as an injectate lumen. Lumen 19 provides distal or pulmonary wedge pressure monitoring. ~umen 22 provides pressure monitoring in the area of the transducers, so as to indicate their position and serves as an injectate lumen.
It has been found that these seven lumens can be provided in ~lexible plastic tubing 13 having an outside diameter of 0.098 inches plus or minus .003 inches. The outside circular wall 36 has a minimum thickness of approximately 0,007 inches. The septa 37 dividlng the lumens ~hould have minimum thicknesses of approximataly 0.004 inches.
As can be seen ~rom Figure 1, the di~tal extremity or tip 41 of the elongate member 13 is generally U-shaped.
The flexible elongate memher 13 is provided with a substantially straight flexible portion 13a having a length of approximately 110 centimeters. The U-shaped tip 41 configuration has a length of approximately 15 c~ntimeter~ for a total length o~ la5 centimeters ~or the elongate member 13. The ~lexible elongate member 13 i~ provided with another relatively straight p~rtion 13b extending beyond an approximately 90 bend 43. It also i~ provided with another generally straight portion , , , 13c extending beyond a more gently curved approximately 60~ bend 44.
~n inflatable flotation balloon 46 i~ mounked on the distal extremity of the portion 13c by suitable means such as an adhesive. The balloon is formed of a suitable material such as latex and can be inflated and deflated by a fluid passing through an inflation and deflation port 47 which i6 in communication with the balloon inflation lumen 21. The balloon 46 will take a generally spherical configuration as shown in dotted lines when inflated and can be in~lated to a suitable diameter as, for example, 10 to 14 millimeters. As can be seen the portion 13c extends through the balloon and is provided with a distal pressure port 48 which is in communication with the lumen 19.
A thermistor 51 of a conventional construction is mounted in the portion 13c proximal of the balloon 46 intermediate o~ the bend 44 and the balloon 46. It is mounted in the space occupied by the lumen 1~. The thermistor 51 is connected to conductors 31 and 32 which extend through the lumen 13.
Additional ports are provided in the catheter 12 and include a positioning port 54 which is in communication with the lumen 22 and a right atrial pressure port and injectate port 56 which is in communication with the lumen 16. Both of the ports 54 and 56 are located near the distal extremity of the flexible elongate member 13 with the port 54 being located from 1 to 3 centimeters from the proximal end of the bend 43 and the port 56 being located approximately 18 centimeters from khe port 54.
.
, The proximal extremity of the elongate member 13 is connected to a plurality oP ~ittings through a manifold molding 96 as shown in Figure 1. Thus there i5 provided an elongate flexible member 61 which i~ provided with a Luer-type ~itting 62. ~he ~lexible elongate tubular member 61 is aonnected to the right atrial pre~ure lumen 16. Another elongate flexible tubular member 63 is provided with a Luer-type fitting 64 and is connected to the distal pressure lumen 19. Another ~lexible elongate member 66 is connected ~o the balloon inflation lumen 21. A two arm adapter 67 is mounted on the tubular member 66 that is connected to a 6top cock 71 which is provided with a handle 72 and a Luer-type fitting 73. A syringe 74 of a conventional type is provided which carries a fluid of a suitable type such as carbon dioxide which can be used for inflating and deflating the balloon 46. The adapter 67 is also provided with a central arm 76.
The guide wire 29 serves as a positioning and straightening device and extends through the lumen 21 and has a suitable diameter such as .012 inches. The guide wire 29 is formed of a ~uitable material such as stainless steel and is attached to a relatively straight piece o~ hypodermic tube 79 having a suitable diameter ~5 such as 0.042 inches and is also formed of a suitable material such as stainless steel. The tube 79 has a length such that it extends approximately the entire length o~ the flexible elongate member 66. A knob 81 i6 sscured to the proximal extremity of the tube 79 and is u~ed for advancing and retracting the guide wire 29.
The guide wire 29 has a length so that when the knob i6 pushed forward into the central arm 76, the guide wire 29 extends through to the distal extremity or tip 41 of the catheter 12 to ~ubstantially straighten the same to . ~ - ; .
, . : ....
facilitate insertion o~ the catheter 12 into the vessel of the human body and al~o to ~acilitate advancement o~
the same as the inflated balloon 46 is utilized to advance the catheter as hereina~ter de~cribed. A raised section such as solder joint or other means 82 on the tube 79 serves as a stop to prevent retraction of the tube 79 through a removable cap 83 carried by the central arm 76. The proximal extremity of the wire 29 and the tube 79 are joined together by conventional means such as solder or by crimping.
Another flexible elongate element 86 with a Luer-type fitting 87 is provided which is in communication with the positioning pressure lumen 22. Another flexible elongate tubular member ~8 is in communication with the lumen 18. It is provided with a thermodilution connector 89 of a conventional type. Another flexible elongate member 91 is provided which has wires extending therethrough which are connected to the back transducer provided in the lumen 23 and the front transducer wires provided in lumen 17. The elongate member 91 is connected to a connect~r 92 which is connected to all of the wires extending through the elongate member 91.
A manifold molding 96 is provided around the proximal extremity of the flexible elongate member 13 and the distal extremities of the flexible elongate members 61, 63, 66, 86, 88 and 91. A strain relief and reinforcing member 97 formed of a suitable materia~ such as rubber extends out of the molding 96 and covers the proximal extremity 42 of the flexible elongate element 13.
The connector 92 plugs into it~ corresponding connector 101 which is at the end o~ cahle 102 that extends into the front panel 103 of the control console 11. As shown in Figure 1, the control console includes a knob 104 ; ~, , ' , . ,. ~ ' ':
.... , ,-- . .. , i . :
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provided on the front panel 103 which can be utilized for setting the alarm settings of the cardiac output limits and the diameter limits o~ the appar~kus. A
"power on" push button 106 is provided as well as an alarm muting push button 107. In addiklon, push buttons 108 and 109 can be provided for setting "alarm on", and "high" and "low~ alarm limits for the cardiac output.
Similarly, push buttons 111 and 112 can be provided for setting "alarm on", and t'low" and ~high~ alarm limits for the diameter measurement. A graphic display 116 is provided for displaying instantaneous flow waveforms, flow trends or velocity profiles. Mode push buttons 117 are provided for selecting either a "monitor" or "insert" mode. A digital readout 118 is provided for displaying the cardiac output in liters per minute with push buttons 119 and 121 giving the capabilities to provide the mean cardiac and the peak cardiac outputs.
In addition, a digital display 122 is provided for giving a readout of measured parameters such as the diameter of the vessel being monitored in millimeters, stroke volume or a cardiac index. Vertical LCD bars display 123 is provided adjacent the display 116. The bars display 123 by their heights give an indication of the validity of the acoustic information being processed by the control console 11 and thereby give an indication of the efficacy of position of the catheter in making correct velocity and volumetric flow measurements in the vessel in which it is positioned.
In accordance with the present invention, to obtain the 30 type of information which is provided by the console 11, at least four ultrasonic transducers are carri.ed by the catheter 12. Front and back transducers are provided as her~inafter de~cribed. The front transducers typically are mounted within the recess provided by the :, . . . .
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::
, : , - , ' ' ~- :
-12~ ~ f~ 3 i~
lumen 16 wherea~ the back transducere are provided in the lumen 23 which i~ diametrically opposite the lumen 16. The distal extremity bends 43 and 44 are formed within the plane which includes the longikudinal axis of the catheter 12 and a line passing diametrically through the catheter and through the middle of the front and back transducer lumens 16 and 23 respectively. This is necessary to orient the transducer beams such that each lies substantially within a single plane which includes the longitudinal axis of the main pulmonary artery when the catheter's distal extremity 13c is positioned downstream in one of the smaller branches of the right pulmonary artery. This beam positioning is essential to obtain accurate diameter and velocity profile measurements for calculating volumetric blood flow or cardiac output.
In Figures 4A, 4B and 4C, the catheter 12 is shown positioned within a human heart. The introduckion of the catheter 12 through the jugular vein of the patien~
is a technique which is generally well known to those skilled in the art. In order to facilitate introduction, the guide wire 29 is advanced to its extreme distal position by operation of the knob 81 to straighten the distal extremity or tip 41 of the catheter 12 to facilitate introduction of the catheter into the jugular vein o~ the patient. The catheter 12 as showrl in Figures 4A, 4B and 4C passes into the heaxt 161 through the venous port 162 of the superior vena cavae 163, through the right atrium 164, and ~hen through the tricuspid valve lS6, the right ventricle 167, through the pulmonary valve 168, through the main pulmonary artery 1~9 and inko the right pulmonary artery branch 171 and then wedglng downstream ln one of the secondary branches leading from the right pulmonary -13- ~J~
artery branch with the tip o~ the catheter having the balloon thereon being disposed in that branch. In the course of inserting the catheter, i~s location can be monitored by observing the pressure waveforms which are guite distinct from one another in the di~ferent parts of the circulatory sy6tem. Adeguate velocity and diameter determinations can generally be made with the transducers positioned in the region between pulmonic valve 168 and below bifurcation 172.
In the arrangement shown in ~igures l and 3, it can be seen that first, ~econd and fourth ultrasonic transducers Tl, T2 and T4 are carried by the catheter on the front side of the catheter and are spaced longitudinally o~ the catheter 12. The second and fourth transducers or, in other words, the transducers T2 and T4 are spaced apart a predetermined distance.
A third transducer T3 is provided on the back 6ide of the catheter 12 oppo6ite the transducers Tl, T2 and T4 and faces in a direction which is 180 opposed to the direction in which the transducers T2 and T4 face. The transducer T3 may not be necessary when the catheter is immediately adjacent a wall of the vessel. As hereinafter described, the first and second transducer6, transd~cers Tl and T2 serve a~ one set o~ transducers in conjunction with the third transducer T3 and the first and fourth transducers Tl and T4 form another set of transducer~ in conjunction with the third tranæducer T3. ~he control console ll ~erves to supply electrical signals to the transducers through the connecting wires hereinbefore described to cause the transducers to emit ultrasonic energy beams as indicated by the rays Bl, B2, B3 and B4 æhown in Figure 3. The first ultrasonic transducer Tl is positioned on the catheter 50 that it emits an ultrasonic energy beam Bl which is at an angle .
~1 with respact to the longitudinal axis of the catheter 12. The transducers T2, T3 and T4 emit ultrasonic beams B2, B3 and B4 at angles ~2, e 3 and ~4 which are generally perpendicular to the longitudinal axis of the catheter 12. The beams B2, B3 and B4 are directed at angles which are substantially 90 with respect to the longitu~inal axis of the catheter 12. The beam B3 is directed in a direction which is 180 or opposite to that of the beams B2 and B4.
In conjunction with the instrumentation means provided by the control console 11, the first transducer Tl measures the velocity profile of the liquid in the vessel 181 by Doppler shift measurements. The second and fourth transducers T2 and T4 are also used for measuring ~he velocity profile o~ the flow of the liquid in the vessel by Doppler shift measurements and at least a portio~ of the diameter of the vessel at the location that the transducer is positioned on the catheter. The third transducer T3 measures at least a portion of the diameter of the vessel at the location that the transducer is positioned on the catheter. The instrumentation means provided by the control console 11 also includes means for ascertaining which of the first and second sets, or all, of ultrasonic transducers provides optimal velocity pro~ile and diameter measuremen~s.
In the po6ition of the catheter 12, ~hown in Figure 4A, the catheter 12 either becau~e o~ the vasculature of the heart or the longitudinal position of the catheter in the pulmonary artery or vessel in the heart has both o~
the transducers T2 and T4 on the front side of the catheter in good posi~ions to receive the desired information to provide accurate velocity and volumetric A-53061~HCH
' '''"':
-15~ f'~"
blovd flow through ~he vessel. The transducers T2 and T4 are both ln optimum po~itions wikhin the pulmonary artery to make accura~e mea~urement~. In this ~ituation, instrumentatlon 11 w~11 u~e either transducers Tl, T2, and T3 as a ~et, or tran~ducers Tl, T4, and T3 a6 a set. Or, it may u~e all four transducers Tl, T2, T3, and T4 as a set.
In the position of the ca~heter 12, as ~hown in Figure 4B, there is depicted a 6ituation in which the pulmonary artery ie too 6hort in comparison to the ~pacing between the catheter transducers T2 and T4 or the catheter 12 is somewhat proximal to the position where it should be located because the transducer T4 is in a region of or below the pulmonic valve 168 in the heart. For that reason the information supplied by the transducer T4 is inaccurate or inappropriate. However, the transducer T2 is still in a good position and therefore the instrumentation ll will ascertain that this information is appropriate information and will supply the appropriate measurements utilizing transducers Tl, T2 and T3 as the set of transducers, rather than the transducers Tl, T4 and T3 as the 6et of transducers.
In Figure 4C there is depicted a situation in which the transducer T2 may not provide good information with the ~ituation being that the catheter 12 has been pushed too far di6tally or the pulmonary artery is quite long in comparison to the spacing between the tran~ducers T2 and T4. In ~uch a ~ituation the in6trumentation ll will select the transduc~rs Tl, T3 and T4 as belng the transducers to be utllized rather than the transducers Tl, T2 and T3. The diameter transducers are used two at a time to measure diameter when the catheter 12 i~
not immediately adjacent a wall of the ve~sel. Thue, , ~ . . . ~ ~ , . . , .; . :: .
- . . : . :: .
- :: : . . : : . : :
: . : . . , : :
-16- 7 J~
eithex T2 and T3 or T3 and T4 are used to measure the diameter of the vessel.
I~ the catheter 12 is positioned in such a manner that neither o~ the transducer~ T2 and T4 in conjunction with transducers Tl and T3 can provide good signals to provide accurate velocity profile and volumetric flow measurements, this situation i8 sensed by the instrumentation or control console 11, and an error signal will be provided on the control console 11 which will appear on the digital di6play. However, it can be seen that an error ~ignal will only be generated by the control console 11 when neither the transducers T2 and T4 in conjunction with transducers Tl and T3 will provide a good measurement. Becauss of this factor, the position of the catheter 12 is much less position dependent and thus will give a range of accurate readings in a wider range along the longitudinal axis of the catheter 12 than would be possible with a single transducer such as transducer T2 or transducer T4.
It should be appreciated that if desired the fourth transducer T4 rather than being a diameter transducer can be positioned at an angle similar to transducer Tl to be a velocity transducer (see Fig. 5A). This would make it possible to select either of the velocity transducers Tl or T4 using always the two diameter transducers T2 and T3.
It should also be appreciated that if the ~ourth transducer T4 rather than being primarily a diameter transducer iB instead a velocity transducer eimilar to Tl, its beam direction can be opposite to that of Tl.
That is if beam Bl points upstream, beam B4 would point downstxeam, as in Fig. 5B.
, . . . . . . . .
It should also be appreciated that transducers T1, T2, T3 and T4 can be in other order~ and directions, depending on the algorithms used to analyze the velocity and diameter in~ormation and per~orm the ~low calculations. As examples, Tl, T3 and T4 could be primarily for diameter~ measurements, with T2 being used ~or velocity measurements (see Fig. 5c). Or, T3 and T4 could be used primarily for diameter measurements with Tl and T2 being for velocity measurements (See Fig. 5D).
In the past, a pressure psrt has been located adjacent to the transducers and this pressure port has been utilized as a key for positioning the catheter.
However, with respect to the present catheter, this pressure pork is merely used as a reference point when the positioning of the catheter has been accomplished more effectively by utili7ing error criteria to determine the proper position of the catheter. This can be readily accomplished by utilizing error criteria in an algorithm incorporated into so~tware implemented within the control console 11 to establish whether or not the diameter and the velocity ~ignals being received are in ~act accurate measurements. Appropriate data would be incorporated into the algorithm by channeling the algorithm. By channeling the algorikhm data parallel with the signals being received from the transducer, the control console 11 can be utilized to detect errors in the input signals. Utilizing such information, appropriate instruction6 can be provided on the control console 11 to facilitate positioning of the catheter 12 in the vessel. For example, instructions can be given to advance or retract the catheter to improve the signal~ being received.
. ...
' .'., ' ~
- .: .:
: : :
From the foregoing, it can be seen that there has been provided a volumetric flow measuring apparatus and method which is less position dependent. Because of the use of an additional transducer or transducers, the need for repositioning of the catheter is substantially reduced. Real time feedback i8 provided to aid in positioning of the catheter. Error criteria are defined such that gradual signal degradation or improvement is displayed continuously to aid in placement of the catheter by the physician while at the same time optimizing a displayed figure of merit for the received signals from the transducers.
It also has been found that in order to make the volumetric flow measuring apparatus and method less dependent upon positioning of the catheter that it is desirable to provide a catheter which does not utilize a movable guidewire. Such a catheter 201 is shown in Figures 6 and 7. The ~atheter 201 shown therein is adapted to be substituted for the catheter 12 and is adapted to be connected to the control console 11 shown in Figure 1. This catheter 201 in many respects is very similar to the catheter 12 shown in Figure 1 with the exception that the guidewire 79 utilized in the catheter a~sembly shown in Figure 1 is eliminated. Also a gentle substantially J-shaped bend is provided in the distal extremity of the catheter 201 rather than the generally U-shaped bend provided in Figure 1.
The catheter 201 6hown in Figure 6 consi~ts of a flexible elongate member 202 formed of plastic. A cross section like Figure 2 taken of the flexible elongate member in the position shown in Figure 1 would provide a similar cross section in which a total of sev2n lumens are provided in the flexible elongate member 2~2.
: . . . : , . , " - . : . , . .
.: ~; ~ . : : , ~ .
, : . ~ ; . . . .
, . . , " ~ ~ , The flexible elongate member 202 is provided with a relatively straigh~ flexible portion 202a having a suitable length as for example approximately 110 cm up to a bend 203 of approximately 15 to 20 after which there is provided another flexible relatively straight portion 202b up to a bend 204 of another ~mall angle as fvr example 15 to 20 after which there is provided another flexible relatively straight portion 202c extending to the distal extremity of the catheter 201.
Thus, the bend 203 forms an angle of approximately 165 to 160 and bend 204 forms an angle of approximately 165 to 160. Thus it can be sePn that the bend 203 and 204 in the distal extremity of the catheter 201 provide a very gentle curvature which represents a substantially modified J-bend. An inflatable latex balloon 206 is provided on the distal extremity of the flexible elongate member 202 and is adapted to he inflated and deflated through a port 207.
A thermistor 211 is mounted in the portion 202c adjacent the bend 204. Transistors T1, T2, and T4 are mounted on the front side of the flexible elongate member 202 proximal of the bend 203 and the transistor T3 is provided on the backside of the member 202 opposite and between the transducers T2 and T4. However, it should be appreciated that the four transducers can be arranged in any of the manners heretofore desoribed. A main pulmonary artery port 212 is provided in the ~lexible elongate member 202 slightly proximal of the transistor T4 and a right atrial port 213 is provided proximal of the port 212.
Markers 216 visible to the human eye of a conventional type are provid2d on the exterior surface of the flexible elongate member 202 and are spaced . .
-, , , ' '.~',, . . . ' : ~
~ - ; . - . . , ~ .
-20- , ~ 5 ~ s longitudinally thereof. The markers 216 ~erve to indicate to the ~urgeon how far the ~atheter 201 has been introduced into the patient.
The proximal extremity of the flexible elongate member 202 is connected through a manifold 221 to a plurality of flexible elongate members 222, 223, 224, 226, 227 and 228. The flexible elongate member 222 is connected to the distal pressure lumen and is provided with a Luer adap~er 231 at its proximal extremi~y. The flexible elongate member 223 carries the conductors provided in the flexible elongate member 202 connQcted to the devices in the catheter. The conductors in the elongate member 223 are connected to an electrical connector 232 at the proximal extremity of the flexible elongate member 223. The flexible elongate member 224 is provided with a Luer adapter 233 at its proximal extremity. The flexible elongate member 226 is provided with an electrical connector 234 adapted to be connected to a conventional thermodilution console (not shown).
The flexible elongate member 227 is connected to the balloon inflation lumen and is provided with a stop cock 236 which is secured to the flexible elongate member 227 with an adapter 237. The stop cock 236 i6 provided with a Luer type ~itting 238 and a handle 239. The flexible elongate member 228 is connected to the right atrial pressure lumen and is provided with a Luer adapker 240.
Suitable means is provided for giving additional stif~ne6s to the rlexible elongate member 202 which i6 just short of the pre-~ormed bend 03 to provide support and additional rigidity to the catheter throughout substan~ially i~e entire length except in ~he region of the pre-formed bend 203 and beyond to the distal extremity of the catheter. The predetermined bends 203 --2 ~ , !i J
and 204 have been provid~d in the flexible elongate member 202 to provide stability ~or the catheter 201 when the catheter 201 i8 positioned in the pulmonary artery. One means ~or providing thi~ additional rigidity and 6tiPfness in the flPxible elongate member 202 is obtained by utilizing a flexible elongate element 241 in the form of a wire of a suitable mat2rial such as stainless steel. The wire 241 has a length so that it extends substan~ially the entire length of the flexible elongate member 202. Its proximal extremity 241a has a suitable diameter such as .014" which diameter continues ~or a suitable distance as ~or example 70 cm. The wire 241 is then taper ground to a diameter of .012" to provide a portion 241b that extend6 for approximately 20 additional centimeters. Another taper grind then reduces the diameter of the wire 241 to .009" to provide a portion 241c which extends for approximately another 20 centimeters to a region adjacent the transducers Tl to T2, T3 and T4 and in the region of these transducers a portion 241d ie provided on the wire 241 which has a larger diameter of .014" for a distance of 2 to 3 centimeters. The wire portion 241d serves to provide increased stif~ness in the region of the catheter 201. The distal extremity of the wire 241 is provided with a portion 241e which has a continuous taper in which the diameter o~ the wire is reduced ~rom . 014" to .0025" to give additional flexibility to the distal extremity of the wire 241. A coil spring 242 is mounted on the wire 241 by having the tapered portion 241e extend into the coil 242 and be secured thereto by suitable means such as solder. The spring 242 is formed o~ a suitable material such as .002" diameter stainle~s steel wire. The spring has a suitable outside diameter as for example .014" and a length of approximately 2 cm.
The wire 241 with the spring 242 i6 positioned so the .; .
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spring 242 is just short o~ the bend 203. This makes it possible for the distal extremity o~ the catheter 11 to have good flexibility so that it can be floated into the desired position upon inflation of the balloon 206.
At the same time, wire 241 provides additional rigidity to the catheter 201 to facilitate its insertion into ths vessel of the patient.
The proximate extremity of the wire ~41 is provided with a right angle hook portion 241f which is positioned in a hole 244 in the adapter 237 and is retained therein by the stopcock 236 (see Figure 7).
The use of the catheter 201 in the volumetric flow measuring apparatus shown in Figure 1 is very similar to that hereinbefore described in conjunction with the apparatu~ shown in Figure 1. However, it ha~ been ~ound that the catheter 201 makes the catheter less position dependent because the elimination of the movable wire removes another variable in the positioning of the catheter in a desired position within the heart of the patient. This is true because after removal o~ the movable wire from the distal extremity of the catheter, the distal extremity of the catheter has a different flexibility than when the guidewire was positioned in the distal extremity making it more difficult for the instrumentation 11 to ascertain whether or not the catheter 12 has been properly positioned in the heart.
With the use of the fixed wire which only extends up to the bend 203, the flexibility of the distal extremity of the catheter 201 remains constant. The fixed wire 241 provides additional rigidity throughout the remainder of the catheter while providing the desired transitions in flexibility in the regions leading up to the portions of the catheter carrying the transducers , .. . : ~, , ~ . . ;
~ ~ r~
Tl, T2, T3 and T4 while still providing the desired rigidity within the catheter at that region. The spring 242 provides graduated transi~ion at the distal extremity of the wire 241 and provides a r~l~tively blunt end so that the wire 2~1 will not puncture the flexible elongate element 202. Alternatively if desired the spring 242 can be eliminated and a blunt end can be formed on the end of the wire 241 ~or a similar purpose.
The relatively small angle preformed bends 203 and 204 provided in the distal extremity o~ the catheter 201 make it possible for the catheter 201 to negotiate the vessels of the patient and make it possible to facilitate positioning the distal extremity of the catheter in the appropriate position in the heart to thereby properly position the transducers Tl through T4.
The bends 203 and 204 also provide the necessary stability for the distal extremity of the catheter during the time that measurements are being made by the instrumentation console ll from information supplied by the transducers Tl through T4.
From the foregoing it can be seen that the catheter which is shown in Figures 6 and 7 can be utilized in the volumetric flow measuring apparatus and method heretofore described to provide a less position dependent apparatus and met~od. The elimination of the movable wire eliminates one additional variable ~rom the system. Thls makes it possible to more accurately predict when the catheter has been properly positioned in the heart to make accurate volumetric ~low measurement~.
.
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, .
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Claims (22)
1. In an apparatus for measuring the volumetric flow of a liquid in a vessel having a wall and having an axis extending longitudinally of the vessel parallel to the vessel wall, a flexible catheter having an longitudinal axis adapted to be disposed in the vessel, said catheter having front and back sides, first, second, third and fourth transducers carried by the catheter, said first, second and fourth transducers being disposed on the front side of the catheter and the third transducer being positioned on the back side of the catheter, said second and fourth transducers being spaced apart a predetermined distance, the first, second and third transducers comprising a first set of transducers and the first, third and fourth transducers comprising a second set of transducers, instrumentation means connected to the first, second, third and fourth transducers, said instrumentation means including means for causing the first, second, third and fourth transducers to emit ultrasonic energy beams therefrom, the first transducer being positioned on the catheter to emit an ultrasonic energy beam at an angle with respect to the longitudinal axis of the catheter, the second and third transducers being positioned in the catheter to emit ultrasonic beams extending generally perpendicular to the longitudinal axis of the catheter, the fourth transducer being positioned so that it emits an ultrasonic beam, said instrumentation means includes means for receiving the signals from the first, second, third and fourth transducers and for measuring the velocity of profile of the flow of liquid in the vessel by Doppler shift and for ascertaining the diameter of the vessel in the vicinity of the transducers, said instrumentation means including means for ascertaining which of said first and second sets of transducers provides more accurate velocity profile and diameter measurements of the vessel.
2. Apparatus as in Claim 1 wherein said instrumentation means includes means for ascertaining which set of transducers provides an optimal measurement.
3. Apparatus as in Claim 1 wherein said instrumentation means includes means for generating an error signal when accurate velocity and diameter measurements cannot be ascertained from either the first and second sets of transducers.
4. Apparatus as in Claim 1 wherein said instrumentation means includes means for periodically sampling the output from the first and second sets of transducers and for switching from one set of transducers to another set of transducers in the event the measurements from one set of transducers is better than the measurements from the other set of transducers.
5. Apparatus as in Claim 1 wherein the fourth transducer is positioned so that it measures the diameter of the vessel.
6. Apparatus as in Claim 1 wherein said fourth transducer is positioned so that the beam therefrom extends at an angle with respect to the longitudinal axis so as to be capable of measuring velocity of the flow of liquid in the vessel.
7. Apparatus as in Claim 1 wherein a catheter has a distal extremity and wherein first and second bends are provided in the distal extremity and wherein the first, second, third and fourth transducers are positioned in the proximity to the first bend of the catheter.
8. Apparatus as in Claim 7 wherein said catheter is provided with a supplemental means for providing additional graduated stiffening to the catheter from the proximal extremity of the catheter to a portion which just extends beyond the first, second, third and fourth transducers positioned in the catheter.
9. Apparatus as in Claim 8 wherein said graduated stiffening means includes means which provides increased stiffness in the catheter in the vicinity of the first, second, third and fourth transducers to compensate for openings provided in the catheter to accommodate the transducers.
10. Apparatus as in Claim 7 wherein said supplemental stiffening means is in the form of a wire extending through the catheter.
11. Apparatus as in Claim 10 wherein the wire is provided with a distal extremity together with spring means secured to the distal extremity of the wire.
12. In a method for measuring the volumetric flow of a liquid in a vessel which has a wall and an axis extending longitudinally of the vessel parallel to the vessel wall by the use of a flexible catheter which has a longitudinal axis and is adapted to be disposed in the vessel and in which the catheter is provided with first, second, third and fourth transducers, the first, second and fourth transducers being positioned on one side of the catheter and the third transducer being positioned on the opposite side of the catheter, the first, second and third transducers comprising a first set of transducers and said first, third and fourth transducers comprising a second set of transducers and instrumentation means connected to the first, second, third and fourth transducers for supplying energy to the transducers and for receiving energy from the transducers, the steps of sensing one set of transducers and then sensing the other set of transducers and ascertaining which of the first and second sets of transducers provides accurate velocity and diameter measurements.
13. A method as in Claim 12 together with the step of selecting one of the first and second sets of transducers for providing velocity and diameter measurements.
14. A method as in Claim 12 together with the step of periodically sampling the other set of transducers after the first set of transducers has been selected to ascertain whether more accurate information is being provided by the other set of transducers and when such is the case switching to the other set of transducers for providing the velocity and diameter measurements.
15. A method as in Claim 12 together with the step of generating error signal when neither the first nor second set of transducers provides an accurate measurement of the velocity and diameter.
16. A method as in Claim 13 together with the step of repositioning the catheter until the error signal disappears.
17. A catheter for making measurements in a vessel defined by a wall carrying a fluid, comprising an elongate flexible tubular member having a plurality of lumens including a balloon inflation lumen extending therethrough and having proximal and distal extremities, an inflatable balloon carried by the distal extremity of the tubular member and having the interior of the balloon in communication with the balloon inflation lumen in the flexible tubular member, the tubular member having at least one preformed bend therein adjacent the distal extremity of the tubular member, a transducer carried by the tubular member in the region of the preformed bend, conductive means connected to the transducer and carried by the tubular member and extending through one of the lumens in the tubular member to the proximal extremity of the tubular member, the tubular member having an opening in the distal extremity distal of the balloon in communication with one of the lumens in the tubular member, and fixed wire means disposed in one of the lumens and extending through said one of the lumens into a region which is just short of the preformed bend so that the fixed wire provides support for the catheter throughout substantially its entire length except in the region of the predetermined bend and beyond to the distal extremity, the shape of the predetermined bend being such so that it provides stability for the catheter when the catheter is positioned in the pulmonary artery.
18. A catheter as in Claim 17 wherein said fixed wire is solid and is formed of stainless steel and has a distal extremity together with a coil spring secured to the distal extremity of the fixed wire.
19. A catheter as in Claim 17 wherein said fixed wire is provided with portions having diameters of decreasing size extending in a direction towards the distal extremity of the wire with the exception of a portion in the vicinity of the transducer.
20. A catheter as in Claim 17 wherein said fixed wire extends through the balloon inflation lumen which is used for inflating and deflating the inflatable balloon, said fixed wire having a proximal extremity and means for securing the proximal extremity of the wire in the balloon inflation lumen.
21. A catheter as in Claim 17 together with a stop cock carried by the balloon inflation lumen.
22. A method for introducing a catheter for making measurements in a vessel defined by a wall carrying a fluid by utilizing a catheter having an elongate flexible tubular member having a plurality of lumens extending therethrough and having proximal and distal extremities, an inflatable balloon carried by the distal extremity of the tubular member and having the interior of the balloon in communication with one of the lumens in the flexible tubular member, the tubular member having at least one preformed bend therein adjacent the distal extremity of the tubular member, a transducer carried by the tubular member in the region of the preformed bend, conductive means connected to the transducer and carried by the tubular member and extending through one of the lumens in the tubular member to the proximal extremity of the tubular member, the tubular member having an opening in the distal extremity distal of the balloon in communication with one of the lumens in the tubular member and fixed guide wire means disposed on one of the lumens and extending through said one of the lumens to a region which is just short of the preformed bend so that the fixed guide wire provides support for the catheter throughout substantially its entire length except in the region of the predetermined bend and beyond towards the distal extremity, the method comprising introducing the catheter into the vessel, inflating the balloon to permit the balloon to float in the fluid in the vessel and to further advance the catheter in the vessel and manipulating the catheter to cause it to advance into the right atrium, the right ventricle and into the main pulmonary artery and into the right branch of the pulmonary artery.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US581,012 | 1984-02-17 | ||
| US07/581,012 US5121749A (en) | 1988-10-05 | 1990-09-12 | Position in dependent volumetric flow measuring apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2051152A1 true CA2051152A1 (en) | 1992-03-13 |
Family
ID=24323551
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2051152 Abandoned CA2051152A1 (en) | 1990-09-12 | 1991-09-11 | Less position dependent volumetric flow measuring apparatus, catheter for use therein, and method |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US5121749A (en) |
| EP (1) | EP0475773A1 (en) |
| JP (1) | JPH05146439A (en) |
| CA (1) | CA2051152A1 (en) |
Families Citing this family (36)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5207226A (en) * | 1991-01-25 | 1993-05-04 | Regents Of The University Of Minnesota | Device and method for measurement of blood flow |
| US6387052B1 (en) * | 1991-01-29 | 2002-05-14 | Edwards Lifesciences Corporation | Thermodilution catheter having a safe, flexible heating element |
| US5553622A (en) * | 1991-01-29 | 1996-09-10 | Mckown; Russell C. | System and method for controlling the temperature of a catheter-mounted heater |
| US5720293A (en) * | 1991-01-29 | 1998-02-24 | Baxter International Inc. | Diagnostic catheter with memory |
| US5205292A (en) * | 1991-06-03 | 1993-04-27 | Applied Biometric, Inc. | Removable implanted device |
| US5174299A (en) * | 1991-08-12 | 1992-12-29 | Cardiac Pacemakers, Inc. | Thermocouple-based blood flow sensor |
| US5339816A (en) * | 1991-10-23 | 1994-08-23 | Aloka Co., Ltd. | Ultrasonic doppler blood flow monitoring system |
| US5207228A (en) * | 1992-01-21 | 1993-05-04 | Baxter International Inc. | Dual port thermodilution catheter |
| US5246007A (en) * | 1992-03-13 | 1993-09-21 | Cardiometrics, Inc. | Vascular catheter for measuring flow characteristics and method |
| US6623516B2 (en) * | 1992-08-13 | 2003-09-23 | Mark A. Saab | Method for changing the temperature of a selected body region |
| US5335663A (en) * | 1992-12-11 | 1994-08-09 | Tetrad Corporation | Laparoscopic probes and probe sheaths useful in ultrasonic imaging applications |
| US5421334A (en) * | 1993-10-06 | 1995-06-06 | Cardiovascular Imaging Systems, Inc. | Pre-filled imaging catheter |
| US5439003A (en) * | 1993-12-16 | 1995-08-08 | Modern Technologies Corp. | Apparatus and method for measuring fluid flow |
| US5453576A (en) * | 1994-10-24 | 1995-09-26 | Transonic Systems Inc. | Cardiovascular measurements by sound velocity dilution |
| WO1996016600A1 (en) * | 1994-11-30 | 1996-06-06 | Boston Scientific Corporation | Acoustic imaging and doppler catheters and guidewires |
| EP0750879B1 (en) * | 1995-06-29 | 2000-11-29 | Schneider (Europe) GmbH | A medical appliance for pressure measurement in a blood vessel |
| US6582392B1 (en) * | 1998-05-01 | 2003-06-24 | Ekos Corporation | Ultrasound assembly for use with a catheter |
| US6676626B1 (en) | 1998-05-01 | 2004-01-13 | Ekos Corporation | Ultrasound assembly with increased efficacy |
| US6986744B1 (en) * | 1999-02-02 | 2006-01-17 | Transonic Systems, Inc. | Method and apparatus for determining blood flow during a vascular corrective procedure |
| US6435037B1 (en) | 2000-01-06 | 2002-08-20 | Data Sciences International, Inc. | Multiplexed phase detector |
| US6595071B1 (en) | 2000-01-06 | 2003-07-22 | Transoma Medical, Inc. | Estimation of error angle in ultrasound flow measurement |
| US6539316B1 (en) | 2000-01-06 | 2003-03-25 | Data Sciences International, Inc. | Phase detector |
| US6585660B2 (en) | 2001-05-18 | 2003-07-01 | Jomed Inc. | Signal conditioning device for interfacing intravascular sensors having varying operational characteristics to a physiology monitor |
| AU2002359576A1 (en) | 2001-12-03 | 2003-06-17 | Ekos Corporation | Catheter with multiple ultrasound radiating members |
| US6663570B2 (en) * | 2002-02-27 | 2003-12-16 | Volcano Therapeutics, Inc. | Connector for interfacing intravascular sensors to a physiology monitor |
| US7134994B2 (en) * | 2002-05-20 | 2006-11-14 | Volcano Corporation | Multipurpose host system for invasive cardiovascular diagnostic measurement acquisition and display |
| US10182833B2 (en) | 2007-01-08 | 2019-01-22 | Ekos Corporation | Power parameters for ultrasonic catheter |
| US9380992B2 (en) * | 2007-03-30 | 2016-07-05 | General Electric Company | Method and apparatus for measuring flow in multi-dimensional ultrasound |
| US9044568B2 (en) | 2007-06-22 | 2015-06-02 | Ekos Corporation | Method and apparatus for treatment of intracranial hemorrhages |
| US20120245457A1 (en) * | 2011-03-25 | 2012-09-27 | Crowley Robert J | Ultrasound imaging catheters and guidewires with non-interfering and coordinated position and orientation sensors |
| US10888232B2 (en) | 2011-08-20 | 2021-01-12 | Philips Image Guided Therapy Corporation | Devices, systems, and methods for assessing a vessel |
| US9339348B2 (en) | 2011-08-20 | 2016-05-17 | Imperial Colege of Science, Technology and Medicine | Devices, systems, and methods for assessing a vessel |
| US9320493B2 (en) * | 2014-07-08 | 2016-04-26 | Nadarasa Visveshwara | System and method for measuring fluidics in arteries |
| EP3307388B1 (en) | 2015-06-10 | 2022-06-22 | Ekos Corporation | Ultrasound catheter |
| EP3962364A4 (en) | 2019-05-01 | 2023-08-30 | Bard Access Systems, Inc. | Puncturing devices, puncturing systems including the puncturing devices, and methods thereof |
| CN114964066B (en) * | 2022-08-02 | 2022-11-25 | 深圳市海清视讯科技有限公司 | Measuring device and screening system |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4674336A (en) * | 1984-11-01 | 1987-06-23 | Johnston G Gilbert | Volumetric flow rate determination in conduits not directly accessible |
| US4637401A (en) * | 1984-11-01 | 1987-01-20 | Johnston G Gilbert | Volumetric flow rate determination in conduits not directly accessible |
| DE3639321A1 (en) * | 1985-12-18 | 1987-08-06 | Karl Dr Wernecke | Angiographic catheter set having a sound microprobe for the sonographic visualisation of vessels |
| US4721115A (en) * | 1986-02-27 | 1988-01-26 | Cardiac Pacemakers, Inc. | Diagnostic catheter for monitoring cardiac output |
| US4869263A (en) * | 1988-02-04 | 1989-09-26 | Cardiometrics, Inc. | Device and method for measuring volumetric blood flow in a vessel |
| US4947852A (en) * | 1988-10-05 | 1990-08-14 | Cardiometrics, Inc. | Apparatus and method for continuously measuring volumetric blood flow using multiple transducer and catheter for use therewith |
-
1990
- 1990-09-12 US US07/581,012 patent/US5121749A/en not_active Expired - Fee Related
-
1991
- 1991-09-11 CA CA 2051152 patent/CA2051152A1/en not_active Abandoned
- 1991-09-12 JP JP23334791A patent/JPH05146439A/en active Pending
- 1991-09-12 EP EP19910308363 patent/EP0475773A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| JPH05146439A (en) | 1993-06-15 |
| EP0475773A1 (en) | 1992-03-18 |
| US5121749A (en) | 1992-06-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |