Abstract: A flexible elongate member such as a pressure guide wire (1000) includes an electrical device such as a pressure sensor (1002). The pressure sensor (1002) is electrically connected to conductive bands (304), (306) and (308) located on electrical connector (300). The electrical connector is attached to core wire (602) and shaft or hypotube (704). The use of electrical connector (300) helps minimize the assembly time of pressure guide wire (1000), as well as minimize some of the assembly problems associated with prior art designs such as pressure guide wire (100).

Abstract: The invention relates to a resonance based pressure transducer system, insertable into a living body for the in vivo measurement of pressure. It comprises a pressure sensor (2) having a mechanical resonator (16), the resonance frequency of which is pressure dependent; and a source of ultrasonic energy (4). The sensor (2) is mechanically coupled to said source (4) of ultrasonic energy, and the sensor and the source of ultrasonic energy are provided on a common, elongated member (6) at the distal end thereof. A system for pressure measurement comprises an AC power supply, a resonance based pressure transducer system, and a control unit for controlling the supply mode of the AC power, and for analyzing a resonance signal emitted from the resonance based pressure transducer system.

Abstract: A catheter for sensing vertebrate conditions has plural piezoresistive sensors directly electrically coupled to discrete application specific integrated circuits. A mechano-responsive element is in pressure sensitive relationship with the piezoresistive sensor to act as a transfer medium through which vertebrate conditions such as pressure, temperature, water, glucose, and pH are transferred. Each integrated circuit is electrically coupled to a data acquisition system with monolithic circuitry in order to amplify and multiplex signals from multiple sensors.

Abstract: A ball-shaped semiconductor monitoring device (150) having one or more transducer functions for use with an instrument that is insertable into a human body. In one disclosed embodiment, a needle (130) and modified stylet (140) are inserted into intraluminal body cavities for measuring fluid pressure. The modified stylet (140) has the monitoring device (150) attached to one end. The stylet (140) has a metal annulus (142) extending throughout its length and a communication wire (144) disposed therein. The wire (144) is surrounded by an insulator (146) to electrically isolate it from the stylet (140). A recessed cavity (148) is provided at the distal end of the stylet (140) to accommodate the ball monitoring device (150). A transducer (152) is integrated on the ball device (150) to measure such quantitative conditions as pressure. The ball (150) has a ground terminal (154) and a data terminal (156).

Abstract: A body implantable pressure sensor attached to an endocardial lead for implantation in a heart chamber or cardiac blood vessel for sensing blood pressure and providing blood pressure signals to an implanted or external hemodynamic monitor and/or therapy delivery device and method of fabrication thereof. A pressure sensor module is formed of an elongated receptacle having an elongated receptacle cavity for receiving a calibrated, micro-machined pressure transducer having a pressure responsive element. The receptacle cavity is covered by a diaphragm disposed alongside the lead body and in parallel with the lead axis. The receptacle cavity is filled with a incompressible oil for transferring pressure forces that are applied to the diaphragm to the pressure transducer. The oil is introduced through a fill port, and the fill port is sealed after the oil is introduced to prevent leakage of the oil from the receptacle cavity and to complete the hermetic sealing of the receptacle cavity.

Abstract: A sensor mounted on the distal end of an intra-corporeal catheter detects pressure applied thereto. The sensor includes a chip that is deformable in accordance with pressure applied thereto, strain gauges mounted on the chip, a sensing plate, a projection, a cap and a tube. A cover covers the chip, the sensing plate, the projection and the cap and gives a smooth tapered shape to the catheter's distal end. The projection and the cap transmit pressure applied to the catheter's distal end to the sensing plate and tilt the sensing plate in accordance with the pressure. The strain gauges issue detection signals according to the degree and the direction of the tilting. The pressure applied to the catheter's distal end is detected based on the issued signals.

Abstract: A sensor device (20) comprises a sensor package (22) having a cavity (24) formed therein, a sensor die (26) mounted on a bottom surface (28) of the cavity (24) and a protective coating (30) formed over the sensor die in the cavity. The protective coating (30) is formed from a material, preferably a polymer material, which is arranged to have a graduated cross-linking density such that the material at the top of the cavity (24) has a high density of cross-linking and the material at the bottom of the cavity (24), which material is in contact with the sensor die, has a low density of cross-linking.

Abstract: A flexible elongate member such as a pressure guide wire (1000) includes an electrical device such as a pressure sensor (1002). The pressure sensor (1002) is electrically connected to conductive bands (304), (306) and (308) located on electrical connector (300). The electrical connector is attached to core wire (602) and shaft or hypotube (704). The use of electrical connector (300) helps minimize the assembly time of pressure guide wire (1000), as well as minimize some of the assembly problems associated with prior art designs such as pressure guide wire (100).

Abstract: An apparatus and method for obtaining pressure data using a body implantable pressure sensor includes a measurement capacitor which is responsive to pressure changes of a body fluid. Non-constant, multiple current source charging of the measurement capacitor provides for a significant increase in sensitivity to conditions of pressure of a body fluid. Pressure data is obtained by charging the measurement capacitor at a first charge rate during a first charge period of an integration cycle and, during a second charge period of the integration cycle, charging the measurement capacitor at a second charge rate. The first charge rate is preferably greater than the second charge rate. The duration of the first and second charge periods may be varied. A signal indicative of a pressure change of a body fluid imparted to the measurement capacitor is produced by the pressure sensor. The signal may be a signal indicative of a change in a time of integration.

Abstract: A pressure sensor includes a tube for channeling a fluid therethrough. A seat is disposed in an outer surface of the tube, with a flexible diaphragm at the bottom thereof. The diaphragm is planar, and blends at its perimeter coextensively with an arcuate inner surface of the tube. A gauge is mounted in the seat above the diaphragm for measuring flexure thereof under pressure of the fluid inside the tube.

Abstract: A pressure sensing device includes a housing having an interior sized for containing a flexible diaphragm, the deflection of which causes subsequent movement of a movement mechanism relative to an indicating dial face. The diaphragm is nonfixedly attached to the bottom side of a support plate disposed within the housing interior, in which the plate includes a center opening sized to support the movement mechanism and position an input member of the movement mechanism adjacently to the flexible diaphragm. A pressure chamber is established between the bottom of the housing and the diaphragm such that air or other fluid entering the chamber causes deflection of the diaphragm and subsequent movement of the input member. Preferably, the diaphragm is retained within a slot formed in the housing and clamped into contact with a flexible gasket and the bottom surface of the support plate.

Abstract: A cannula that is usable to remove blood from a patient during an operation such as bypass surgery where the cannula has a pressure sensor in the form of an electronic piezoresistive chip located at or adjacent the location within the heart where the blood is being removed. The crystal has a sensing side and a reference side that is exposed to a reference pressure that is known. The piezoresistive chip is mounted at the distal end of the cannula such that its sensing side faces outwardly away from the central bore of the cannula that is transporting the blood that is being removed and thus is isolated from the dynamic effects of the moving blood. In addition, the pressure sensor has a characteristic drift based on temperature and the sensor is therefore standardized at body temperature, 36 degrees Centigrade, so that the pressure sensor is standardized at the temperature at which it will be used when positioned within the patient.

Abstract: A pressure transducer arrangement featuring a holding element for a number of pressure transducers. For each pressure transducer a group of electronic counter-contacts is provided on the holding element that are in contact with the contacts of the pressure transducer while it is attached to the holding element. All counter-contacts are connected to one common signal transfer device.

Abstract: A catheter-based physiological pressure sensing device, which can be calibrated in vivo, is disposed in the distal end of a catheter, and is preferably in the form of a bulb-like device. The pressure sensing device includes a pressure sensor tip and pressure sensor element disposed in the pressure sensor tip. The pressure sensor element has first and second opposing surfaces which form separate and isolatable first and second chambers. An aperture is formed in an external wall of the pressure sensor tip to provide a passageway into the first chamber and expose the first surface of the pressure sensor element to a physiological pressure. A blocking element, such as a balloon, is disposed in the first chamber and is adapted for selectively blocking the aperture.

Abstract: A physiological pressure transducer is disclosed which can be adapted for multiple uses and which employs a low cost semiconductor strain gauge sensor. The transducer is connected to a fluid-filled catheter/manometer system for measuring pressures inside a living body in areas of medical interest such as the heart, brain, uterus, or the vascular system. The catheter is coupled to the pressure transducer through a unique, disposable dome containing a shaped, compliant isolation media which is in intimate contact with the transducer diaphragm. The complete assembly is adapted for use with standard catheter flushing solutions and flush devices. An improved method of drawing blood samples by using the features of the assembly is also described.

Abstract: A guide wire having pressure sensing capabilities for measuring the pressure of liquid in a vessel comprising a flexible elongate member and having proximal and distal extremities and having an outside diameter of 0.018" or less. The distal extremity of said flexible elongate member is adapted to be disposed in the liquid in said vessel. A housing is carried by the flexible elongate member and has a diameter substantially the same as the diameter of the flexible elongate member. The housing has a space therein with a pressure sensor mounted in the space in the housing. The pressure sensor has a diaphragm that is sensitive to changes of pressure in the liquid in the vessel. The diaphragm is rectangular in shape and is bordered by a rim surrounding the well. A backing plate is formed of an insulating material bonded to the crystal and serves to reinforce the rim of the crystal of semiconductor material.

Abstract: A system for chronically measuring a physiologic parameter by an implantable device which has several forms is described. At its core a fixture for holding on to a blood vessel and forcing a sensor against a surface of the vessel is taught. Numerous adaptations and uses with various sensors are described.

Abstract: A method for construction ond delivery of a novel implantable medical device provides for use of a kit having sizeable fixture components for holding a blood vessel and a sensor portion connectable during surgery to the appropriately sized fixture.

Abstract: An apparatus and method for calibrating the pressure readings obtained by catheter tip pressure transducers. The apparatus includes a Plexiglas vessel covered by a closure containing eight catheter ports through which the transducers are introduced into the vessel. The vessel is filled with saline solution that has been warmed to body temperature. The transducer ends of the catheters are inserted through airtight hemostatic control valves into the vessel through the catheter ports. Plexiglas guide tubes are used to guide the transducers into the saline solution at predetermined distances below the surface of the saline solution. The distances are used to calculate the hydrostatic pressures exerted upon the transducers by the saline solution. Known pressures are applied to the transducers through an airtight pressure port in the closure. Calculated hydrostatic pressures are added to the known pressures to provide calibration pressures for comparison with monitored pressure readings.

Abstract: This invention relates to a blood pressure transducer (8) and provides a safe and economical transducer by providing a novel optical fiber (80) made of a transparent elastomer. The present invention provides an invasive direct blood pressure transducer (8) of an external sensor system consisting of a catheter (1a), a pressure tub (6) connected to the catheter at one of the ends thereof and a pressure transducer (8) connected to the other end of the pressure tube (6), part of the pressure transducer is composed of an optical fiber (80) made of a transparent elastomer.

Abstract: A sensor mechanism-equipped catheter is easy to produce, suitable for a diameter reduction, and achieves a high sensing precision. In a catheter, a sensor assembly has a pressure-receiving piston, a pressure-transmitting silicon gel or oil and a pressure sensor chip, and is fitted to a distal end of a catheter tube. The sensor assembly detects a pressure change. The sensor assembly further has an outer tube that carries the piston at a distal end side thereof, and an inner tube carrying the sensor chip an end side thereof. A space formed in the outer tube, between the piston and the sensor chip, is filled with the silicone gel or oil. A pressure barrier wall is provided for blocking flow of the silicone gel toward the catheter tube. The sensor chip is fixed in the sensor assembly by a joining member which divides an interior space of the sensor assembly into a distal end-side region and a base end-side region. The joining member may also serve as the pressure barrier wall.

Abstract: A physiological pressure transducer is disclosed which can be adapted for multiple uses and which employs a low cost semiconductor strain gauge sensor. The transducer is connected to a fluid-filled catheter/manometer system for measuring pressures inside a living body in areas of medical interest such as the heart, brain, uterus, or the vascular system. The catheter is coupled to the pressure transducer through a unique, disposable dome containing a compliant isolation media which is in intimate contact with the transducer diaphragm. The complete assembly is adapted for use with standard catheter flushing solutions and flush devices. An improved method of drawing blood samples by using the features of the assembly is also described.

Abstract: A biological pressure measuring system with a transmission device for transmitting a biological pressure at a biological location to a pressure monitor/transducer for measuring the biological pressure. An atmospheric pressure transmission device transmits an atmospheric pressure at a reference location to a reference pressure device for measuring atmospheric pressure and a vertical fluid pressure of the fluid in the atmospheric transmission device. The reference pressure device generates a reference pressure signal with a reference excitation signal representing a pressure of the fluid from the atmospheric pressure transmission device, a vertical distance between the reference location and the reference pressure transducer device being substantially similar to a vertical distance between the transducer and biological location. A signal connection device combines the biological pressure signal and the reference pressure signal into a combined signal.

Abstract: A captive deadender cap for use in venting the patient side chamber of a disposable pressure transducer through a vent port. The captive deadender cap includes retention tabs formed along the internal threads of the standard Luer threads of the deadender cap and which create a resistance with the mating external threads of the female Luer fitting on the vent port. Thus the captive deadender cap is not easily removable but is held captive to the vent port. By an increase in the torque, however, the resistance may be overcome by the user and, if desired, the captive deadender cap may be fully removed from the vent port.

Abstract: A device for measuring body fluid pressure, such as blood pressure, muscle compartment pressure, and spinal column pressure, is herein described. An invasive implement is inserted into a body area, and a fluid path extends from the body area into a fluid channel in the device. A valve is used to control the flow of fluid through the device and a pressure sensor is placed adjacent to the fluid channel, with the pressure sensor and/or a sealant gel forming a portion of the fluid channel. With the valve closed, pressure builds in the fluid channel and the pressure sensor detects the resulting pressure, and a pressure transducer and supporting electronics converts and communicates the pressure measurement. With this device the pressure sensor can detect pressure without contacting the fluid, so therefore a pressure can be taken with a minimum of fluid extraction. If fluid extraction is desired, the valve is opened and fluid flows from the body area to a fluid port where the fluid may be collected.

Abstract: An intravascular device for measuring blood pressure and flow is disclosed, which includes an elongate shaft having a pressure transducer and a flow transducer connected to its distal end. The pressure transducer may be a ferrofluid-type pressure transducer and the flow transducer may be an anemometer-type flow transducer. Measurement circuitry is also disclosed which provides a means for simultaneous measurement of both blood pressure and blood flow parameters. A sensor shield may be employed to isolate radial blood flow which is indicative of turbulent blood flow. An alternative blood flow measurement device is also disclosed which utilizes a thin metal film anemometer to measure flow in a vascular lumen.

Abstract: A flow-through cell for extra-corporeal measurement of blood parameters has a pressure sensor arranged in a measurement chamber. The pressure sensor has an active pressure sensor part and an inactive pressure sensor part. The inactive pressure sensor part is constructed identically to the active pressure sensor part, and is insulated from the pressure prevailing in the measurement chamber by a rigid covering. The active and inactive sensor parts produce respective electrical signals which are subject to the same disturbing influences, so that by subtracting the signal of the inactive sensor part from the signal of the active sensor part, a measured value free of disturbing influences is obtained.

Abstract: A medical pressure transducer includes a reusable component with channels to either side of a reusable diaphragm, and a disposable dome with mounting wings to either side of a disposable diaphragm and slidably receivable in the channels to mount the dome with the diaphragms in confronting relationship. Stand-off bumps are provided on the wings which cooperate with support surfaces on the reusable component in the channel to keep the dome and reusable diaphragms sufficiently spaced apart as to minimize deleterious wear thereon when the dome and reusable component are put together and/or taken apart. Dimples may be provided in the support surface to receive the bumps when the diaphragms are in confronting relationship and no longer need to be spaced sufficiently apart. Camming ramps are provided in the channels and on the wings by which to drive the dome diaphragm into the reusable diaphragm.

Abstract: A bioinstrumentation device utilizes an optical fiber for measuring biological parameters such as heart rate and breathing rate of a human subject. The device utilizes an optical fiber as a sensing element for sensing minute load variations resulting from the heart beating and breathing of the human subject and therefore indicative of the heart rate and the breathing rate. The device includes a base and a movable member movable relative to the base. The movable member is connected to a support structure for the human body and receives the minute load variations from the living body so as to vibrate in response thereto. Disposed between the base and the movable member is the optical fiber which is capable of resiliently deforming with changing characteristic of its internal reflectivity. A light source is disposed adjacent to the input end of the optical fiber to feed a light through the optical fiber.

Abstract: A balloon catheter includes an elongate pliable catheter tubing with a dilatation balloon fixed to the catheter tubing near its distal end. The dilatation balloon includes a first wall for dividing the balloon into a plurality of dilatation compartments adjacent one another and arranged angularly about the catheter tubing. Each dilatation compartment is fluid tight and in fluid isolation from other compartments. The compartments are individually controlled so the pressure within each balloon compartment may be adjusted as determined by the operator. The dilatation balloon includes a second wall composed of the respective outer wall portions of the dilatation compartments which defines an outer transverse profile of the dilatation balloon and adapted to form surface engagement with the tissue segments surrounding the balloon when the compartments are dilatated.

Abstract: A guide wire that is capable of sensing the phasic pressure at the distal end of the guide wire. The guide wire has a central lumen which provides a non-compliant fluid path from the distal end of the guide wire to a pressure transducer at the proximal end of the guide wire.

Abstract: A medical pressure transducer includes a reusable component with channels to either side of a reusable diaphragm, and a disposable dome with mounting wings to either side of a disposable diaphragm and slidably receivable in the channels to mount the dome with the diaphragms in confronting relationship. Camming ramps are provided in the channels and on the wings by which to drive the dome diaphragm into the reusable diaphragm. Where the channels are defined behind outer front walls, the outer surface of one is provided with a tab-receiving slot to receive a locking tab associated with dome to lock diaphragms into confronting relationship. The dome includes second wings spaced from the mounting wings to receive the outer front walls. The second wings have finger gripping portions one of which is a locking paddle supporting the lock tab. In alternative embodiments, the dome wings are edges, fixed or resilient, receivable through slots formed in the reusable component.

Abstract: A catheter that is guided into an intra-corporeal passageway is set forth. A catheter tube accommodates an element having a piston for detecting a pressure in the intra-corporeal passageway. Silicone gel is accommodated in the catheter tube to transmit the detected pressure in the catheter tube. A strain gage is disposed on a semiconductor chip to output an electric signal based on an amount of a deformation thereof indicative of the pressure in the catheter tube.

Abstract: A region of interest in a living body is exposed to excitation light, which causes it to produce fluorescence. The fluorescence is separated with respect to desired wavelength ranges and detected. A first detector detects an entire fluorescence component or a fluorescence sum component, which is the sum of a fluorescence component of a comparatively short wavelength region and a fluorescence component of a comparatively long wavelength region. A second detector detects a fluorescence component of a comparatively long wavelength region or a fluorescence difference component, which is the difference between a fluorescence component of a comparatively short wavelength region and a fluorescence component of a comparatively long wavelength region. The output from the first detector and the output from the second detector are divided by each other. The fluorescence intensity depending upon the distance with respect to the region of interest is thus corrected such that no error may occur in making an operation.

Abstract: A blood pressure monitor kit suitable for use in emergency scenarios such as cardiopulmonary arrest situations. The kit includes a catheter for insertion in the femoral artery of the patient, a transducer arranged to receive blood pressure signals from the catheter and operative to convert the blood pressure signals into electric signals; a housing; a monitor mounted in the housing and including electric circuitry arranged to receive the electric signals from the transducer and operative to generate at least one display indicative of a condition of the patient's blood pressure; a battery positioned within the housing and operative to power the electric circuitry; a switch associated with the housing for connecting the battery into the electrical circuitry to power the circuitry; and a securement device on the housing operative to secure the housing to a patient's body at a location proximate the location of the catheter insertion.

Abstract: The present invention provides an diagnostic apparatus and method for physiologically measuring the biological responses of a selected group of muscles during exercise. Biological responses measured include blood flow, blood pressure, transcutaneous oxygen, and lymphatic clearance rate. The apparatus comprises a pressure plate attached to an axle. A spring mechanism is attached to the pressure plate to bias the plate towards the resting position. The spring may be adjusted so as to increase the resistance to the group of muscles being exercised and induce fatigue.

Abstract: An in vivo rezero apparatus for a pressure transducer is disclosed. This invention includes embodiments where both sides of the pressure transducer are exposed to atmospheric pressure to rezero the pressure transducer and embodiments where both sides of the pressure transducer are exposed to physiologic pressure to rezero the pressure transducer.

Abstract: A catheter provided with a catheter tube that is inserted into a human body. A sensor detects pressure acting on a distal end of the catheter tube when inserted into the human body and outputs an output signal indicating fluctuations of the pressure. A CPU judges whether the waveform of the output signal contains a regular component and an irregular component and separates the output signal into a regular component and an irregular component based on the judgment. Based on the separated irregular component, a judgment is made as to whether an obstruction is present within an insertion path of the catheter.

Abstract: A medical pressure transducer includes a reusable component with channels to either side of a reusable diaphragm, and a disposable dome with mounting wings to either side of a disposable diaphragm and slidably receivable in the channels to mount the dome with the diaphragms in confronting relationship. Camming ramps are provided in the channels and on the wings by which to drive the dome diaphragm into the reusable diaphragm. Where the channels are defined behind outer front walls, the outer surface of one is provided with a tab-receiving slot to receive a locking tab associated with dome to lock diaphragms into confronting relationship. The dome includes second wings spaced from the mounting wings to receive the outer front walls. The second wings have finger gripping portions one of which is a locking paddle supporting the lock tab. In alternative embodiments, the dome wings are edges, fixed or resilient, receivable through slots formed in the reusable component.

Abstract: The present invention is a pressure monitor for measuring the pressure in a liquid in catheter, comprising a light emitting device, a photosensitive device receiving the light from the light emitting device and transforming the light received into electric signals. The invention also includes a measuring zone. The light transmitted through the measuring zone varies in accordance with the pressure in the catheter.