Patent Application
20250128043
The present invention is directed to a fluid management system designed for treating fluid management disorders in a patient, and related components and methods. In particular, the present invention is directed to sensors and hardware used in intravascular catheters for monitoring and/or managing pressure within a blood vessel.
The invention provides systems and methods for controlling the operation of intravascular catheters to treat fluid management disorders such as acute decompensated heart failure, chronic heart failure, ascites, lymphedema, chronic kidney disease, cardiac insufficiency, cardiac value regurgitation, or plural effusions. In particular, the invention provides a console, for use in a clinical setting, where the console controls operation of an intravascular catheter. The console includes a controller with treatment logic and a connected hub. The hub has a connection point to which an intravascular catheter can be connected. When the intravascular catheter is connected to the hub, the controller executes instructions and operates devices on the catheter to relieve the fluid management disorder.
For example, the catheter may include a flow restrictor such as a balloon, or a pump such as an impeller. The console system can take measurements, such as intravascular blood pressure measurements, and execute instructions to operate the catheter. In particular, in preferred embodiments, the system is operable to calculate and use an offset that ensures that corrected fluid pressure values with great precision and accuracy are shown to a physician and/or used in operating the catheter.
Preferably, the console operates the intravascular catheter using intravascular measurements and optionally the offset to treat fluid conditions that impact interstitial (e.g., extravascular) and/or microcirculatory fluid management. To ensure the physician has the most precise and accurate fluid pressure information, the system uses stored correction data (such as calibration data and or thermal sensitivity data and/or drift characteristic data), intracorporeal and/or ambient sensors, and/or calibration/correction instruction programming to determine an “offset” and correct/adjust the direct pressure measurements to more accurate and precise “true” values, useful to precisely guide therapy. The calculated offset(s) are useful as “correction factors”. In one illustrative example, a blood pressure sensor in a jugular may return a reading of 5 mm Hg. But the controller (in the console) uses the correction data and logic (e.g., ambient pressure sensor, stored calibration data, thermal correction data, etc.) to determine and apply the “offset” so that the console can display to the physician that “true” blood pressure in the jugular is, in fact, 8 mm Hg, with significant implications for lymphatic return.
The offset may be calculated using such data as thermal sensitivity data, calibration data, ambient temperature, drift characteristic data or pressure measurements. The controller receives a baseline pressure reading and uses the offset to calculate a corrected “true” fluid pressure in the patient. This precise and accurate “true” pressure is used to inform a physician and/or operate the catheter and relieve the fluid disorder.
In some embodiments, for a patient undergoing acute decompensated heart failure, the system can operate the catheter to create a low pressure region in a venous angle at an outlet of a lymphatic duct. Such embodiments illustrate that consoles of the system include programming logic and data that allow intravascular or circulatory measurements and operations to address interstitial and microfluidic conditions. That is, systems and methods of invention that bridge a gap between intravascular treatments and fluid management as a whole. Bodily fluid systems naturally involve a variety of fluidic systems beyond and adjacent blood vessels, including lymphatic systems with lymphatic vessels and ducts as well as interstitial fluids that play vital health roles outside of vessels and ducts. Systems and methods of the invention use consoles with programming logic and additional data to calculate offsets and aid physicians in treating fluid management disorders holistically, to correctly and appropriately treat aspects of fluid management disorder that reach beyond the principle circulatory system.
Systems and methods of the invention are operable to control a pump, such as an impeller disposed on an intravascular catheter. The impeller may be driven by a motor, which may be at the impeller or in a connected hub. A controller of a console provides instructions and programming logic controlling operation of the pump.
For example, the pump may be controlled using pressure measurement feedback to adjust the pump operation until a target pressure is achieved. Additionally, systems and methods of the invention may include a variety of systems and features for safe operation of intravascular catheters. In an example, a controller (e.g., in a console) of the invention may use a determined corrected pressure measurement to operate a pump (e.g., impeller) while also limiting operation to a safe speed (flow volume). In another example, systems and methods of the invention use temperature and/or pressure measurements to avoid operating an impeller under conditions that promote hemolysis (e.g., shut down or slow down impeller at critical temperature/pressure combinations). Some embodiments detect evidence of the beginning of hemolysis via evidence of impeller resistance or reduced rotational speed, where the system can display a caution on a display of the console or change operation, e.g., change operation of the impeller. Programming logic and instructions in the controller thus aid in controlling operation of a pump to effectively treat fluid management conditions and also keep the entire system operating within safety parameters.
Various aspects of the present invention are directed to systems and methods for conducting a fluid management therapy that effectively monitors pressure during the fluid management procedure and reliably treats fluid management disorders in a patient.
In one aspect, the present invention provides a method of treating a patient with fluid management disorder using an intravascular catheter having pressure sensors. The method includes the steps of
In a second aspect, the present invention provides a method for monitoring pressure during a fluid management procedure using an intravascular catheter having pressure sensors. The method for monitoring includes the steps of
In a third aspect, the present invention provides a method for restricting fluid flow in a blood vessel using an intravascular catheter with a pressure sensor and a restrictor. The method for restricting fluid flow includes the steps of
In a fourth aspect, the present invention provides a system for pumping body fluids, the system comprises a pump assembly designed for deploying inside a human body, a controller with a microprocessor and a software designed to operate the pump assembly, a motor configured to drive a pumping element of the pump assembly.
For example, in one aspect the present invention provides a motor control system for pumping body fluids during an intravascular fluid management procedure. The system Includes:
In one embodiment, the pump assembly comprise a blood pump. The pump assembly Includes, in some embodiments, a housing encasing the pumping element. The pumping element, in some embodiments, includes an Impeller.
In some embodiments, the switch element comprises a plurality of switch states. In examples, the switch states comprises a first state and a second state. During the first state, in some embodiments, electron flow between the primary control circuit and motor is facilitated. In other embodiments, during the first state, electron flow between the primary control circuit and the motor is blocked. During the second state, in some embodiments, electron flow between the secondary control circuit and motor is facilitated. Likewise, in other embodiments, during the first state, electron flow between the primary control circuit and the motor is blocked. Further, in some embodiments, the plurality of switch states comprises a third state. Switching the switch element from the first state to the second state causes the motor to operate at a preset rotation speed limit, in some embodiments. In some embodiments, switching the switch element from the first state to the second state causes the motor to operate at a preset lower rotation speed limit. Further, In embodiments, switching the switch element from the first state to the second state causes the motor to operate at a preset standby rotation speed limit.
The hardware controller, in some embodiments, further comprises a current detection element configured to generate an electrical output proportional to the current detection by the current detection element. In some embodiments, the hardware controller further comprises a motor torque detection element configured to generate an electrical output proportional to the torque detected by the torque detection element. The software provides a computational operation on the electrical output of the motor torque detection element, in some embodiments. For example, the computational operation produces a computational output, which is used by the software to manage safe operation of the pump. In some embodiments, the manage safe operation of the pump includes
Further, in some embodiments, the software provides a computational operation on the electrical output of the current detection element. The computational operation produces a computational output, which is used by the software to manage safe operation of the pump. Thus, In some embodiments, the manage safe operation of the pump includes
In some embodiments of systems of the invention, the manage safe operation of the pump includes
These and other aspects and advantages of the present invention are described in the following detailed description of the invention.
Specific embodiments of the present invention are now described in detail with reference to the figures, wherein the reference numbers indicate identical or functionally similar elements. The terms “distal” or “proximal” are used in the following description with respect to a position or direction relative to the treating physician. “Distal” or “distally” are a position distant from or in a direction away from the physician. “Proximal” or “proximally” or “proximate” are a position near or in a direction toward the physician.
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. In the present disclosure, the singular forms “a”, “an” and “the” includes the plural reference. It is to be appreciated that certain features of the invention which are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. That is, unless obviously incompatible or excluded, each individual embodiment is deemed to be combinable with any other embodiment(s) and such a combination is considered to be another embodiment. Conversely, various features of the invention that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub-combination.
The microfluids entering the interstitium 8 in the capillary bed 7 fill the spaces between the interstitial cells 12 referred as the interstitial space 11 and bathe the interstitial cells 12 in fluid that is riche in oxygen and nutrients. Blood separated microfluid entering the interstitial tissues 8 is referred as interstitial fluid. In the process of bathing the interstitial cells, the interstitial fluid carry oxygen and nutrients to these cells and toxins and waste products are allowed to move from the interstitial cells 12 into the interstitial fluids.
The interstitial fluid is collected by lymphatic capillaries 10 which are abundant in the interstitial tissues 8 and the fluid is conveyed by the lymphatic system 25 back to the venous compartment. Interstitial fluid entering the lymphatic capillaries 9 is referred as lymph fluid. In the lymphatic vessels of the gut, this fluid is referred as chyle due to the absorption of fat molecules into lymph fluid in the small intestines of the gut.
The lymphatic system 25 is a complex drainage network that consists of (i) lymphatic collecting vessels which receive fluid from the lymphatic capillaries 10 and carry it to large lymphatic vessels, (iii) lymphangions 14 which are miniature tubular pumping elements with one way value inlets and outlets, smooth muscle cells in its wall structure and a signaling system that controls its pumping action, (iv) lymph nodes 15 which are small multifunctional glands that filter lymph and have other immune functions, (v) lymphatic ducts 16 that collect lymph fluid from the upstream part of the lymphatic system 25 and connect with the great veins 20 via a lymph duct outlet located above the heart 4 to return the lymph to the blood circulatory system.
According to
A lymph flow catheter system 30 according to the present invention is illustrated in
In a preferred embodiment of the lymph flow catheter system 30 according to the present invention, the lymph flow catheter system 30 includes a lymph flow catheter 34 and a console 50. The lymph flow catheter 34 includes a proximal restrictor 41 and a distal restrictor 40 with at least one the restrictors capable of defining a fluid flow path. Both the proximal restrictor 41 and distance restrictor 40 are depicted in the inflated state. In the preferred embodiment, the proximal restrictor 41 includes the fluid flow path. The catheter 34 includes a reduced pressure zone between the proximal and distal restrictors and the system 30 is configured to reduce the pressure in the reduced pressure zone and maintain the pressure in the reduced pressure zone over time. Since the proximal restrictor 41 includes a fluid flow path, a reduced volume of fluid flows across the proximal restrictor 41 and a reduced pressure zone between the proximal and distal restrictor can easily be maintained. For example, the fluid flow path reduces the volume of fluid entering the target zone and thereby making it easier to effect and sustain a pressure reduction in the target zone.
The lymph flow catheter 34 further comprises a blood pump 43 and blood pump 43 pumps blood from the reduced pressure zone to a region downstream of the reduced pressure zone. In one preferred embodiment of the blood pump 43 according to the present invention, the blood pump 43 includes an impeller pump with an impeller 44, an impeller housing 45, a motor 48 and a drive shaft 49 connecting the motor 48 to the impeller 44. In another embodiment, the console 50 wirelessly controls the operation of the motor 48 through communication with a local receiver element connected to the motor 48. The flow path is preferably configured such that a controlled flow of blood always enters the reduced pressure zone during the procedure. The controller of the console 50 controls the rotation of the impeller 44 to maintain the pressure in the reduced pressure zone at a constant level even if the pressures in upstream or downstream blood vessels change due to postural changes of the patient, or due to a reduction in venous volume due to diuresis or otherwise.
Preferably, the catheter 34 includes pressure sensors for monitoring pressure within a blood vessel. In one preferred embodiment of the catheter 34 according to the present invention, the catheter 34 includes three pressure sensors. A first pressure sensor 35 upstream of the proximal restrictor 41, a second pressure sensor 36 located between the first and second restrictors 40, 41, and a third pressure sensor 37 distal to the distal restrictor 40. The catheter 34 may include sensor lumens 38 in the wall of the catheter 34. The sensor lumens 38 extend proximally to facilitate intersection with one or more pressure sensor connectors 47. The pressure sensors 35,36, 37 may be configured for placement in sensor lumens 38. The pressure sensors 35, 36, 37 may include a sensing element and a sensor cable 64, the sensing element configured to sense the pressure and generate a signal and the sensor cable 64 configured to transmit the signal. The one or more sensing elements may be configured on the surface of the catheter 34. The one or more sensing elements may be configured in a lumen of the catheter 34. The one or more sensing elements may be configured at a proximal location and hydrodynamically connected to the vessel via a lumen through an opening in the wall of the catheter 34. The catheter 34 may include a sensor lumen outlet, the sensor lumen outlet including an opening or a skive in the wall of the catheter to hydrodynamically connect the sensor lumens 38 to bodily fluid adjacent to the sensor lumen outlet.
The pressure sensors 35, 36, 37 may include optical fiber (MOMS) pressure sensors. The pressure sensors 35, 36, 37 may include resistive or capacitive (MEMS) based pressure sensors. The catheter 34, pressure sensors 35, 36, 37 and controller 50 may be configured for monitoring pressure during the intravascular fluid management procedure. The catheter 34 may be operably connected to the controller 50. In a preferred embodiment according to the present invention, the operable connection includes connecting the pressure sensors 35, 36, 37 to the controller 50 for relaying sensed data for processing.
The system 30 may include stored thermal sensitivity data and/or drift characteristic data for the pressure sensors 35, 36, 37. The stored thermal sensitivity data and/or drift characteristic data may be stored on the controller 50 or a storage element of the catheter 34 or on a memory device connected to the system 30. Thermal sensitivity data and/or drift characteristic data allows the controller 50 to calculate an offset which can be applied when the temperature changes from a first temperature to a second temperature. The offset depends on the type of pressure sensor used and can even be specific to each pressure sensor. The offset ensures that the controller 50 is using accurate data on bodily fluid pressures notwithstanding a change in the operating temperature of the pressure sensors 35, 36, 37. Calculating an offset allows the controller 50 to measure pressure more accurately across a range of temperatures.
The controller 50 may include one or more ambient sensors 62 to measure ambient conditions including ambient pressure and ambient temperature. The one or more ambient sensors 62 are in contact with ambient conditions and include a data connection to the controller 50. The one or more ambient sensors 62 may be on the exterior surface of the controller 50 or may be integrated into a console on which the controller 50 is mounted. Alternatively, the one or more ambient sensor 62 may be wirelessly coupled to the controller 50. The one or more ambient sensors 62 provide accurate data to the controller 50 on ambient conditions. The controller 50 reads the thermal sensitivity data and/or drift characteristic data stored on the system 30, reads the ambient data provided by the ambient sensors 62, reads the pressure data provided by one or more of the pressure sensors 35, 36, 37 and calculates an offset for catheter operation in a body environment.
The controller 50 may also calculate pressure differences between two or more of the pressure sensors 35, 36, 37. The controller 50 provides the data of one or more of the pressure sensors 35,36, 37 to the treating physician. In one of the preferred embodiments, the pressure sensors 35, 36, 37 includes cables for communicating sensed data to the controller 50 and the cables extend from the sensors to the controller 50 for the transmission of sensed data. The system 30 is configured such that the at least one pressure sensors 35, 36, 37 are initialized in advance of conducting a fluid management procedure.
In another preferred embodiment of the system 30 according to the invention, the system 30 includes an intravascular catheter 34 with a first pressure sensor 35, a controller 50 with an ambient sensor 62 and a display 67. The first pressure sensor 35 (or 36 or 37) is mounted on the intravascular catheter 34 and is advanceable with the intravascular catheter 34 and is connected to the controller 50 and transmits pressure sensor data to the controller 50. The ambient sensor 62 is mounted relative to the controller 50 at a location where it can sense ambient pressure (without interference from local heat or cool sources). The ambient sensor 62 may be mounted on the controller 50 or in the controller 50 or on a console that carrier the controller 50 or spaced apart from the controller 50 but in all cases, the ambient sensor 62 is in communication with the controller 50 and transmits data on ambient conditions (pressure, temperature, humidity etc.) to the controller 50. In one preferred embodiment of the ambient sensor 62 according to the invention, the ambient sensor 62 is an absolute pressure sensor.
In second preferred embodiment, the ambient sensor 62 is a pressure sensor and a temperature sensor.
The system 30 includes thermal sensitivity data and/or drift characteristic data and calibration data stored on or connected to the controller 50. At the start of the procedure when the first pressure sensor 35 and the ambient sensor 62 are in a common environment the controller 50 is configured to read the pressure data of the first sensor 35 (or 36, or 37) and read the pressure data of the ambient sensor 62 and calculate an offset that is related to the difference between the reading from the first sensor 35 and the ambient sensor 62, the thermal sensitivity data and/or drift characteristic data of the first pressure sensor 35 and the calibration data of the first sensor 35.
In another variation, the offset is calculated based on the absolute reading of the first pressure sensor 35 (or 36 or 37), the absolute reading or the ambient sensor 62, the thermal sensitivity data of the first pressure sensor 35 (or 36 or 37) and/or drift characteristic data of the first pressure sensor 35 (or 36 or 37) and the calibration data of the first pressure sensor 35 (or 36 or 37).
The controller 50 may be configured to store the value of the offset for use during the procedure or the value may be stored on a memory device. The system 30 is further configured such that when the catheter 34 is inserted into a human body then the display 67 presents pressure data from the first pressure sensor 35 (or 36 or 37) modified by the application of the offset. The pressure data may be presented on the display 67 numerically, charted as a function of time, as a bar chart representation or in other forms that are standard for such data. The controller 50 may include a mobile cart 68 (stand).
The catheter 34 may be configured to increase or decrease bodily fluid pressure in at least a part of the vascular system. The catheter 34, in operation may be adjusted based on pressure measurements of the first pressure sensor 35 (or 36 or 37) and the offset. In one embodiment the first pressure sensor 35 (or 36 or 37) includes an absolute pressure sensor and the ambient sensor 62 includes an absolute pressure sensor.
In another preferred embodiment of the intravascular catheter 34 according to the present invention, the intravascular catheter 34 includes a passive state and an activated state. The passive state includes a delivery configuration, and the active state includes a treatment state.
In a preferred embodiment of the present invention, the initialized pressure reading includes a pressure reading that is adjusted for the ambient pressure in the local region (room, theatre, critical care unit or Cath lab) where the fluid management procedure is being conducted.
In another preferred embodiment of the present invention, the initialized pressure reading includes a pressure reading that is adjusted for the difference between the ambient temperature and the temperature of bodily fluids in the patient.
In yet another preferred embodiment of the present invention, the initialized pressure reading includes a pressure reading that is adjusted for the calibration data or drift characterization data of the of the first pressure sensor 35 (or 36 or 37).
The impeller pump 43 may include an impeller 44 that is housed within an impeller housing in the distal portion of the catheter 34. The impeller housing may further include a number of inlets and outlets for allowing blood flow to move through the distal portion of the catheter 34. The distal balloon 40 is mounted on the impeller housing and is shown in the inflated state where it provides a seal against the wall of the innominate vein 52. In this configuration, the impeller 44 and impeller housing receive blood through the inlets to the impeller pump 43 and pump it out the outlets while the inflated distal balloon 40 prevents downstream blood from flowing retrograde. In this way the catheter 34 maintains a pressure gradient in the vessel that is in opposition to the pressure gradient in the vessel. Blood moves from the proximal side of the distal balloon 40 to the distal side of the distal balloon 40 even though the pressure is lower on the proximal side of the distal balloon 40. With this arrangement the catheter 34 creates a pressure gradient in a vessel and causes blood to flow against the created pressure gradient in the vessel.
In a preferred embodiment and as illustrated in
In one of the preferred embodiments of the proximal restrictor 41 according to the present invention, the proximal restrictor 41 may include a precision restrictor 32. The precision restrictor 32 is configured to expand and oppose the vessel wall and it includes a fluid flow path that allows some fluid from the proximal internal jugular region 54 to flow across the precision restrictor 32 and thereby helps maintain the low-pressure zone 55 at a target pressure by reducing the volume flow rate of fluid entering the low-pressure zone 55.
The controller 50 reads the ambient atmospheric pressure data from the ambient sensor 62 at step 77. The controller 50 subtracts the atmospheric pressure data measurement from the data measurement of the pressure sensor 35 (or 36 or 37) at step 78 to calculate the offset required to zero the pressure sensor 35 (or 36 or 37) of the catheter 34 at step 79. The system zeros the pressure measurement displayed to the user on the display 67 at step 80 and the catheter 34 is now initialized and can be inserted into the patient.
At step 100, the catheter 34 has been initialized and a baseline pressure stored-the initialization pressure. At step 101, the controller 50 reads the pressure at the pressure sensor 35 (or 36 or 37) for a first pressure check. At step 102, the controller 50 checks if the value of the first pressure check has increased relative to the baseline pressure. If the first pressure measurement has not changed relative to the baseline pressure, then the controller 50 returns to step 101 and 102. When the pressure at the pressure sensor 35 (or 36 or 37) has increased above baseline then the controller 50 moves to step 103. In one of the preferred embodiments of the present invention, the step 103 may be skipped and a pressure displayed immediately. At step 103, the controller 50 displays the pressure reading of the pressure sensor 35 (or 36 or 37) on the display 67. This displayed pressure reading has been corrected for local atmospheric pressure and the temperature change from ambient and is an accurate measure of vascular pressure in the region of the pressure sensor 35 (or 36 or 37). The controller 50 checks if the user has continued the procedure at step 104. If yes, then at step 105, the controller 50 reads the pressure at the pressure sensor 35 (or 36 or 37) and at step 103, the controller 50 displays the pressure reading of the pressure sensor 35 (or 36 or 37) on the display 67. At step 104, the controller 50 again checks if the user has continued the procedure. If not the controller 50 proceeds to step 106 and terminates the procedure. It will be appreciated that the controller 50 may circle around the two loops ((i) 101/102 and (ii) 103/104/105) of
The steps are applicable to the system 30 when the catheter 34 of the system 30 is connected to the controller 50. The steps are initiated at step 150. At step 150 the operator initiates steps including steps 150-154. Alternatively, the connection of a hardware element of the system 30 to the controller 50 initiates these steps. At step 151, the controller 50 reads the data of the pressure sensor 35 (or 36 or 37). At step 152, the controller 50 reads the data of the ambient pressure sensor 62. At step 153, the controller 50 subtracts the atmospheric pressure measurement of the ambient pressure sensor 62 from the pressure reading of the pressure sensor 35 (or 36 or 37) and applies temperature sensitivity data and/or drift characteristic data and calibration data offsets to calculate accurately the pressure in the region of the pressure sensor 35 (or 36 or 37). Step 153 may include applying a mathematical calculation wherein the atmospheric pressure measurement and the pressure reading include variable parameters. Step 153 may include applying a mathematical calculation wherein the temperature sensitivity data and/or drift characteristic data and calibration data offsets comprise fixed parameters in the mathematical calculation. It will be appreciated that while the temperature sensitivity data and/or drift characteristic data and calibration data offsets may be fixed for a given temperature and so are fixed variables in one instant calculation they may vary from calculation to calculation. The thermal sensitivity data and/or drift characteristic data may also be variable with respect to time by a factor determined from the initial thermal sensitivity data and/or drift characteristic data. The controller 50 may display the pressure at the pressure sensor 35 (or 36 or 37) on the display 67. The steps end at step 154.
In one preferred embodiment of the first fluid sensor 208, the sensor 208 is configured to measure a fluid parameter, wherein the measured fluid parameter is influenced or controlled by the fluid management catheter 201.
In second preferred embodiment of the first fluid sensor 208, the sensor 208 is configured to measure a fluid parameter, wherein the measure fluid parameter is a measure of the progression of the therapy delivered by the fluid management system 200.
In third preferred embodiment of the first fluid sensor 208, the sensor 208 is configured to measure a fluid parameter, wherein the measured fluid parameter is used by the controller to control the operation of the fluid management catheter 201.
In fourth preferred embodiment of the first fluid sensor 208, the sensor 208 is a pressure sensor and the pressure sensor measures pressure in a circulatory system in the region of the fluid sensor 208.
In fifth preferred embodiment of the first fluid sensor 208, the sensor 208 is a flow sensor and the flow sensor measures the flow or the flow rate of fluid in a vessel of a circulatory system.
In sixth preferred embodiment of the fluid sensor 208, the sensor 208 is an impedance sensor and the impedance sensor takes an impedance measurement in the patient.
The catheter hub 202 further includes a motor 203, a noise and/or vibration damping arrangement 214, fluid sensor PCB 215 and a flushing manifold 216, the flushing manifold 216 including flush ports, stock cocks and/or other standard flushing and inflating components as are standard in interventional catheters. The motor 203 is configured to drive a fluid pump 256 in the catheter 201 and the speed of the motor 203 is controlled by the controller 205. The fluid sensor PCB 215 receives the signal from the fluid sensor 208 and processes the signal before feeding it to the controller 205 via the connection apparatus 204. The motor 203 is mounted in the hub 202 on a noise and/or vibration damping arrangement 214. The noise and/or vibration damping arrangement 214 is configured to allow the motor to operate at very high speeds without the patient or user experiencing excessive noise or vibration during the procedure.
In a preferred embodiment of the noise and/or vibration damping arrangement 214 according to the present invention, the arrangement 214 includes a plurality of rubber rings at least substantially encircling the motor 203 in the hub 202. The plurality of rubber rings may include split rings, or O rings. The plurality of rubber rings may include a rubber, synthetic rubber, elastomer, silicone or foam material. The plurality of rubber rings may include a vibration damping material. The plurality of rubber rings may include a sound absorbing or reflecting material.
In another preferred embodiment of the noise and/or vibration damping arrangement 214 according to the present invention, the arrangement 214 includes a plurality of strips, made from damping material, spaced apart and bonded to the motor 203 longitudinally.
In a preferred embodiment of the connection apparatus 204 according to the present invention, the apparatus 204 includes at least one cable connecting the catheter 201 and hub 202 to the controller 205. In the preferred embodiment, the hub 202 includes a hardware arrangement that allows a wireless connection between the hub and the controller 205. The hardware arrangement of the hub 202 includes a wireless transmitter and receiver, a microprocessor executing firmware and a battery. When operating wirelessly the fluid management system control parameters are received wirelessly from the controller 205. When operating wirelessly the hub 202 sends pressure parameters, pump parameters and information on battery state to the controller. In the preferred embodiment, the battery can be re-charged wirelessly and/or via a cable connection.
In another preferred embodiment, the battery can be removed by a user for charging and replaced while the fluid management system 200 continues to function via power from the connected cable 204 to the controller 205.
The ambient pressure sensor 259 is in communication with the controller 205 and provides the controller with real time measurement of atmospheric pressure in the room where the procedure is being carried out. The ambient pressure sensor 259 may be mounted on or near the controller 205 or it may be in another part of the room.
The fluid management catheter 201 may include a fluid flow restricting catheter, a fluid pumping catheter, a fluid aspiration catheter, a fluid infusing catheter, or a combination of these. The fluid management catheter 201 may include one or more lumens 211. The one or more lumens 211 are arranged in an efficient pattern to minimize the diameter of the catheter. In one pattern the lumens 211 of the catheter 201 may comprise a first central lumen substantially concentric with the OD of the catheter 201 and at least 2 other lumens in the annular wall of the catheter 201 and substantially equally angularly spaced apart.
The fluid management catheter 250 comprises a catheter distal end 212 and a catheter proximal end 213, a pump assembly 256 at the distal end 212 and at the catheter proximal end 213 a hub 202, the hub 202 comprising a motor 203 and hardware, a connection cable 204 and controller connector 258 for connecting the fluid management catheter 250 to a controller 205. The pump assembly 256 includes an impeller housing 253, an impeller 252, the impeller 252 disposed inside the impeller housing 253 and the impeller 252 configured to rotate relative to the impeller housing 253. The pump assembly 256 further includes at least one inlet 254 through which fluid enters the pump assembly 256 under the influence of a negative pressure gradient created by the impeller 252, at least one outlet 255 through which fluid exits the pump assembly 256 and an expandable restrictor 260. The expandable restrictor 260 has a collapsed state and an expanded state and in the expanded state the expandable restrictor 260 apposes the wall of the vessel.
The fluid management catheter 250 of the system 200 further includes a plurality of fluid sensors 251. A first fluid sensor 251a is configured to sense pressure distal of the outlet 255 of the pump assembly 256. A second fluid sensor 251b is configured to sense pressure proximal of the inlet 254 of the pump assembly 256. A third fluid sensor 251c is configured to sense pressure in a proximal region of the vessel, closer to the region where the catheter shaft exits the vessel to the exterior of the body
In one preferred embodiment of the fluid management catheter 250 according to the present invention, the catheter 250 includes a fourth sensor configured to measure the pressure inside the expandable restrictor 260. The diameter of the expandable restrictor 260 may be controlled by pressure or by inflation volume. When the expandable restrictor 260 is in its expanded state and the pump assembly 256 is operating then a pressure gradient is maintained across the expandable restrictor 260 by the operation of the pump assembly 256. If the impeller 252 of the pump assembly 256 is operated at relatively higher speeds, then a greater pressure drop will be maintained across the expandable restrictor 260.
It will be appreciated that the methods for initializing pressure sensors, for monitoring pressure during an intravascular procedure, for providing safety protection hardware and for controlling impeller rotation as illustrated in
In one preferred embodiment of the distal assembly 613 according to the present invention, the distal assembly 613 includes a pressure sensor 601. In one of the preferred embodiments of the present invention, the catheter (34 or 201) includes at least one lumen and the distal assembly 613 is configured for placement inside the at least one lumen, the at least one lumen further including an opening that puts the distal assembly 613 in fluid contact with fluid of the vessel or cavity. The distal assembly 613 further includes an optical fiber pressure measurement assembly comprising a flexible reflective membrane 608, a membrane housing 605 the membrane housing defining a cavity 606 into which the reflective membrane 608 can deflect, a second reflective membrane that provides a fixed reference 607 at the base of the cavity 606. The distal assembly further includes an outer protective housing 609, the outer protective housing 609 configured to protect the sensitive flexible reflective membrane 608 from damage and defining a pressure inlet 610. The protective housing 609 may include a rigid tubing made from metal or an engineering polymer.
The proximal assembly 614 includes an interferometer 603. The interferometer 603 is configured to send and receive light signals to the pressure sensor 601 through fiber optic cable 602. The interferometer 603 includes a light source 611, a detector 612, interferometer PCB 615 and an output cable 604 that relays the pressure measurement data in digital form to the controller (50, 205 or 512) of the system (30 or 200).
As fluid pressure increases in the vessel or cavity the pressure inlet 610 transmits fluid pressure to the flexible reflective membrane 608 and the flexible reflective membrane 608 deforms under the influence of the applied pressure. The position of the flexible reflective membrane 608 changes with respect to the fixed reference 607 and the connected interferometer 603 can sense this change as any distortion will result in a difference between the reflection of the fixed reference 607 and the reflection from the flexible membrane 608.
The interferometer measurement system 603 sends light signals to a connected pressure sensor 601 and the detector 612 detects reflected out of phase signals (interference) in the nanometer range from the connected fiber optic pressure sensor 601. The Interferometer 603 measures changes in the reflected optical signals to nanometer precision and uses stored calibration data from the individual sensor to convert the optical signals to a pressure value by performing a calculation on the processor 616 of the interferometer PCB 615. The interferometer 603 is integrated into a controller unit 50, 205 or 512 that transmits the digital pressure information to a display 67 or 511.
The light source 611 of the interferometer 603 is connected to and controlled by interferometer PCB 615 and is also connected to fiber optic cable 602 and is configured to generate and send light signals to the connected pressure sensor 601 via the fiber optic cable 602. The pressure sensing apparatus 600 is configured for incorporation into fluid management catheters (34, 201, or 505) of the invention. The pressure sensor 601 is configured to establish and maintain hydrostatic contact with fluid of the body vessel or cavity into which the catheter (34, 201 or 505) is placed. The pressure sensor 601 may be on the surface of the catheter (34, 201 or 505), extending from the catheter (34, 201 or 505) or in a hydrostatically connected lumen of the catheter (34, 201 or 505). If the pressure sensor 601 is in a hydrostatically connected lumen of the catheter (34, 201 or 505), then the lumen needs an opening sufficient to establish and maintain hydrostatic contact with fluids of the body cavity or vessel.
In one preferred embodiment of the present invention, the pressure sensor 601 is at a proximal end of a hydrostatically connected lumen. In second preferred embodiment of the present invention, the pressure sensor 601 is at a distal end of a hydrostatically connected lumen.
In one preferred embodiment of the present invention, the proximal assembly 614 is integrated into the catheter (34, 201 or 505). In second preferred embodiment of the present invention, the proximal assembly 614 is integrated into a distal segment of the catheter (34, 201 or 505). In third preferred embodiment of the present invention, the proximal assembly 614 is integrated into a proximal end of the catheter (34, 201 or 505) in another embodiment.
In one preferred embodiment of the present invention, the pressure sensor 601 and the interferometer 603 are in close proximity to one another or are integrated into a single assembly. Preferably the pressure sensor 601 is miniaturized for incorporation into a catheter (34, 201 or 505) or a catheter lumen.
In one preferred embodiment of the present invention, the catheter (34, 201 or 505) includes an indwelling catheter. With this embodiment indwelling means that at least a distal region of the catheter (34, 201 or 505) is configured for insertion into a body vessel or cavity for an extended duration, a period of hours, multiple days or longer or for permanent implantation. Where the interferometer 603 includes a part of an indwelling catheter (34, 201 or 505), the interferometer 603 includes a miniaturized assembly. It will of course be appreciated that a catheter (34, 201 or 505) or system (30 or 200) of the invention may incorporate multiple pressure sensing apparatus 600 to better deliver the fluid management therapy to the patient.
In another preferred embodiment of the sensor carrier 707 according to the present invention, the sensor carrier 707 is configured to protect the piezoresistive silicon membrane 701 from forces of assembly or forces arising from the assembly or manufacturing process.
In yet another preferred embodiment of the sensor carrier 707 according to the present invention, the sensor carrier 707 is configured to protect the piezoresistive silicon membrane 701 from bending forces, torque forces, compressive forces, stretching forces experienced during the delivery or use of the catheter during the fluid management procedure.
In one preferred embodiment of the present invention, the sensor carrier 707 is configured to carry and protect the piezoresistive sensor 700. In this embodiment, the sensor carrier 707 includes a longitudinal channel 712 between two lateral walls 711. The longitudinal channel 712 is configured to facilitate the sliding of the pressure sensor 700 along the longitudinal channel 712 during assembly until it is completely within and protected by the sensor carrier 707. The longitudinal channel 712 may include a partially tube-like element or a profile geometry. The sensor carrier 707 may include a fixing arrangement 708 to hold the piezoresistive sensor 700 at a fixed location in the sensor carrier 707. The fixing arrangement 708 may be a snap fit or an adhesive bond or a formed element.
The piezoresistors of the silicon membrane 701 of the pressure sensor 700 change resistance as it experiences changes in pressure. The pressure sensor 700 further comprises a backing material 714 which provides mechanical support to the piezoresistive silicon membrane 701.
In a preferred embodiment of the piezoresistive sensor arrangement 801 according to the present invention, the piezoresistive sensor arrangement 801 includes sensor controller 802, pressure sensor 700, and a signal processing assembly 804. The pressure sensor 700 includes a first piezoresistive resistor 813 and a second piezoresistive resistor 814 connected in series. The signal processing assembly 804 includes a first resistor 815 with a first known resistance, a second resistor 816 with a second known resistance, a filter 805, a buffer 806 and an analog to digital converter 807. The first resistor 815 and second resistor 816 are arranged with the first piezoresistive resistor 813 and a second piezoresistive resistor 814 to form a Wheatstone bridge 809. A constant voltage or current source 817 is used to supply energy to the bridge circuit. An unprocessed pressure signal 810 is generated by the response of the Wheatstone bridge 809 to a pressure and the unprocessed pressure signal 810 is filtered by passing the signal through filter 805 and buffer 806 to create a filtered analog pressure signal 811. The filtered analog pressure signal 811 is converted to a digital filtered pressure signal 812 by passing the filtered analog pressure signal 811 through an analog to digital converter 807. The digital filtered pressure signal 812 may then be used by the controller 802 in the management of the fluid management procedure. The controller 802 includes a processing unit 808 capable of measuring differences in voltage or current. The signal processing assembly 804 could be incorporated into the hub 202 with or without the sensor controller 802. The functions of controller 802 could be conducted by the controller (50 or 205 or 512) of the system (30 or 200) as described elsewhere in the patent.
In one of the preferred embodiments of the present invention, a constant current or constant voltage can be applied to the Wheatstone bridge 809 and the resulting change in voltages or current used to calculate a pressure by the controller 802 using sensor calibration data. Prior to sending the changes in current or voltage to the processor 808 on the controller 802 the signal is filtered, amplified, and converted to a digital form for transmission.
Referring to the
In a preferred embodiment of the motor control system 901 according to the present invention, the motor control system 901 is configured to maintain the motor (48 or 203) that drives the pump 43 or the impeller 252 at the target speed. To maintain a target speed for the motor (48 or 203) during a therapy procedure, the motor controller 901 is configured to correct for errors introduced by process variables. The motor control system 901 includes a microcontroller or Field-Programmable Gate Array (FPGA) 902, transistor circuit 903, hall sensors 905 and signal conditioner 906. The microcontroller or FPGA 902 further includes a PID controller 907 which is configured to bring the motor 48 or 203 to the target speed in a controlled way and maintain that speed once achieved. In
The microcontroller or FPGA 902 produces an output PWM (Pulse Wave Modulation) that is proportional to the speed calculated by the PID controller 907, that activate switches of the transistor circuits 902 which are connected to a power source. The PWM switching of the transistor circuit 903 allows electrical current to flow directly to the windings in the BLDC motor 904. To accurately control the motor 904, hall sensors 905 are included which send a signal on each revolution of the rotor of the BLDC motor 904. The hall sensor 905 feedback is conditioned by signal conditioner 906 for processing by microcontroller or FPGA 902.
In one of the preferred embodiments of the fluid management system (30 or 200) according to the present invention, the fluid management system (30 or 200) is configured for control of the motor 48 or 203 by current rather than by motor 48 or 203 rotor speed. With this embodiment a target pressure is achieved at the first pressure sensor 35, and/or the second pressure sensor 36 and/or the third pressure sensor 37 by monitoring and controlling the current delivered to the motor (48 or 203). The system (30 or 200) is as described in
In one preferred embodiment of the present invention, the motor (48 or 203) is a BLDC motor or a DC motor without hall sensors and is configured with another means of measuring motor speed such an encoder, tachometer or a signal processor capable of detecting EMF feedback. The alternative speed measurement system may be used to produce an input to a control system. The motor (48 or 203) may also be controlled using compensation circuit (I×R) which increases the motor voltage with increasing motor current (increased torque).
It will be appreciated that the motor controller safety systems 300 of
The motor controller safety system 1500 includes a motor 1501 (which is to be protected from system failures by hardware), a frequency to voltage converter 1502, a reference voltage 1503, a comparator 1504, an OR gate 1505, a control selection multiplexor 1506, a motor controller 1507, a primary DC voltage source 1508, a secondary fixed DC voltage course 1509 and a motor power driver circuit 1510.
The Frequency to Voltage Converter 1502 converts the actual motor speed 1511 to a voltage that is proportional to the actual motor speed. The comparator 1504 compares the converted voltage to a voltage reference 1503. The voltage reference 1503 is a defined threshold voltage that the motor should not normally run at. It is a voltage that signifies that the motor controller 1507 or some other system failure has occurred. The comparator 1504 produces an output signal when the motor speed 1511 has fallen below the threshold. The output of the comparator 1504 is connected to the OR gate 1505. Also connected to the OR gate is an output from the motor controller 1507. The motor control has an output 1512 that is only activated in the event of a failure of the motor controller 1507. If either the comparator 1504 output or the motor controller 1507 output 1512 are active then the OR gate 1505 produces an active output. The output of the OR gate is connected to the control selection multiplexor 1506. An active signal from the OR gate 1505 causes the multiplexor 1506 to switch its input. The multiplexor 1506 has two inputs. The first input of the multiplexor is the motor controller 1507. The default state of the multiplexor 1506 is such that the motor controller 1507 is directly connected to the motor power driver circuit 1510. The motor controller is capable of producing an output 1513 that drives the motor power driver circuit. In one embodiment this may be multiple phased PWM signals. The motor controller 1507 is capable of varying the speed of the motor 1501 by varying the output 1513. The motor controller 1507 is capable of maintaining a target speed received from another circuit. In another embodiment it is capable of maintaining a target torque/current received from another circuit. The motor controller is connected to a primary DC voltage source 1508 that is separate from the secondary fixed DC voltage source 1509. The second input of the multiplexor 1506 is connected to the secondary fixed DC voltage source 1509. The secondary fixed voltage source 1509 is capable of producing a voltage at a defined threshold to support running the motor 1501 at a low speed. In one embodiment these may be multiple phased PWM signals. If the multiplexor is activated by a signal from the OR gate 1505 it will switch inputs to the secondary fixed DC voltage source 1509 resulting in the secondary fixed DC voltage source 1509 being connected directly to the motor power driver circuit 1510. The motor power driver circuit 1510 is connected directly to the motor 1501. In one embodiment the motor power driver circuit 1510 deliver the desired voltage and current to each coil of a BLDC motor. In another embodiment it drives a single phase DC motor.
In another embodiment the hardware system 1500 may be modified to include in addition a low current/torque detection circuit, using elements similar to elements of the system described in the hardware system 300, with an appropriate resistor value for the current sense resistor 301, to detect a low current that is compared by comparing two voltages, one being a low voltage, by means of a comparator that is connected to the OR gate 1505. In another embodiment the low current/torque detection circuit may substitute the low speed detection element.
In another embodiment the hardware system 1500 is combined with the hardware system 300 to provide a system that has safety elements including motor operation at a fixed low speed or current/torque in the event of the primary motor control system failure, disabling of the motor controller when current/torque limits are exceeded and disabling of the motor controller when a high speed limit is exceeded.
While there have been described what are believed to be the preferred embodiments of the present invention, those skilled in the art will recognize that other and further changes and modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the true scope of the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2023/000069 | 2/3/2023 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63306248 | Feb 2022 | US |
