Abstract: A method for determining a value of a parameter of an object or an environment includes positioning a device having a balanced circuit in or on an object or within a particular environment, wherein the balanced circuit comprises elements which are operationally sensitive to changes in a parameter of the object or the environment. The method further includes measuring a common mode signal of the balanced circuit and determining, from the common mode signal, a value of the parameter. An exemplary implementation of the method includes determining temperature using a resistive sensor having a Wheatstone bridge circuit with two variable resistors and two fixed resistors. Embodiments of systems and devices configured to employ such methods are provided, particularly medical probes, electronic signal monitoring devices, and systems employing such devices.

Abstract: A method for determining a value of a parameter of an object or an environment includes positioning a device having a balanced circuit in or on an object or within a particular environment, wherein the balanced circuit comprises elements which are operationally sensitive to changes in a parameter of the object or the environment. The method further includes measuring a common mode signal of the balanced circuit and determining, from the common mode signal, a value of the parameter. An exemplary implementation of the method includes determining temperature using a resistive sensor having a Wheatstone bridge circuit with two variable resistors and two fixed resistors. Embodiments of systems and devices configured to employ such methods are provided, particularly medical probes, electronic signal monitoring devices, and systems employing such devices.

Abstract: A method for determining a value of a parameter of an object or an environment includes positioning a device having a balanced circuit in or on an object or within a particular environment, wherein the balanced circuit comprises elements which are operationally sensitive to changes in a parameter of the object or the environment. The method further includes measuring a common mode signal of the balanced circuit and determining, from the common mode signal, a value of the parameter. An exemplary implementation of the method includes determining temperature using a resistive sensor having a Wheatstone bridge circuit with two variable resistors and two fixed resistors. Embodiments of systems and devices configured to employ such methods are provided, particularly medical probes, electronic signal monitoring devices, and systems employing such devices.

Abstract: A system for monitoring a pH level of a sample medium is disclosed herein as including a pH probe having a pH-sensitive electrode, a reference electrode and a temperature electrode arranged within a housing of the pH probe. The probe housing generally includes a flexible inner tube and a flexible outer tube, the inner tube being concentrically arranged within the outer tube. Preferably, a size of the probe housing minimizes the amount of trauma introduced by insertion of the pH probe into physiological tissues, muscles or fluids. The system also includes a processing means, which is coupled to the pH probe for determining the pH of the sample medium. A method of forming a pH-sensitive electrode, a method of manufacturing a pH probe, and a method for using a pH probe are also disclosed herein.

Abstract: The present invention relates to a pressure sensor module for use in catheters having a pressure sensor operable to provide a signal representative of pressure. The pressure sensor includes a sensing side and a pressure reference side. At least one signal transmission media is coupled to the sensor for transmitting the signal representative of pressure. A convex-shaped carrier is provided having a slot formed to expose the sensing side of the sensor. The convex-shaped carrier is adapted for receiving the sensor such that the sensing side of the sensor is adjacent the slot. A bonding material is provided for mounting the sensor to the carrier. The pressure sensing module provides ease of installation and manufacture because the module may easily be bonded to and installed within a catheter.

Abstract: A system for monitoring a pH level of a sample medium is disclosed herein as including a pH probe having a pH-sensitive electrode, a reference electrode and a temperature electrode arranged within a housing of the pH probe. The probe housing generally includes a flexible inner tube and a flexible outer tube, the inner tube being concentrically arranged within the outer tube. Preferably, a size of the probe housing minimizes the amount of trauma introduced by insertion of the pH probe into physiological tissues, muscles or fluids. The system also includes a processing means, which is coupled to the pH probe for determining the pH of the sample medium. A method of forming a pH-sensitive electrode, a method of manufacturing a pH probe, and a method for using a pH probe are also disclosed herein.

Abstract: A system for monitoring a pH level of a sample medium is disclosed herein as including a pH probe having a pH-sensitive electrode, a reference electrode and a temperature electrode arranged within a housing of the pH probe. The probe housing generally includes a flexible inner tube and a flexible outer tube, the inner tube being concentrically arranged within the outer tube. Preferably, a size of the probe housing minimizes the amount of trauma introduced by insertion of the pH probe into physiological tissues, muscles or fluids. The system also includes a processing means, which is coupled to the pH probe for determining the pH of the sample medium. A method of forming a pH-sensitive electrode, a method of manufacturing a pH probe, and a method for using a pH probe are also disclosed herein.

Abstract: A device, system, and method for determining the sensing performance of pressure-sensing devices. The device generates dynamic pressure waveforms that enable researchers and medical personnel to accurately assess the characteristics and performance of a particular pressure-sensing device. The system and methods allow for comparison of performance between two or more pressure-sensing devices, including catheter tip pressure transducers and fluid-filled catheters. The system may also be used to practice priming and preparing catheters for insertion into a living body, as the system provides immediate feedback that may indicate the presence of air in the system.

Abstract: The present invention relates to a pressure sensor module for use in catheters having a pressure sensor operable to provide a signal representative of pressure. The pressure sensor includes a sensing side and a pressure reference side. At least one signal transmission media is coupled to the sensor for transmitting the signal representative of pressure. A convex-shaped carrier is provided having a slot formed to expose the sensing side of the sensor. The convex-shaped carrier is adapted for receiving the sensor such that the sensing side of the sensor is adjacent the slot. A bonding material is provided for mounting the sensor to the carrier. The pressure sensing module provides ease of installation and manufacture because the module may easily be bonded and installed within a catheter.

Abstract: The present invention relates to a catheter pressure transducer having a pressure sensing module operable to provide a signal representative of pressure. The pressure sensor includes a sensing side and a pressure reference side. At least one signal transmission media is coupled to the sensor for transmitting the signal representative of pressure. A convex-shaped carrier is provided having a slot formed to expose the sensing side of the sensor. The convex-shaped carrier is adapted for receiving the sensor such that the sensing side of the sensor is adjacent the slot. A bonding material is provided for mounting the sensor to the carrier. The pressure sensing module provides ease of installation and manufacture because the module may easily be bonded and installed within a catheter.

Abstract: An inverted sensor module for sensing physical and chemical fluid characteristics in a vessel in a living body. The inverted sensor module includes an inverted sensor bonded to a hollow carrier so that sensing occurs in the lumen of the inverted sensor module. An inverted sensor module comprising one or more inverted sensors is implantable and allows fluid to flow through, thereby allowing for measurements of acute and chronic conditions. The inverted sensor module may be used in series with other inverted sensor modules to assess trends such as pressure gradients along a bloodstream.

Abstract: An external fluid-filled catheter pressure transducer for monitoring fluid pressure characteristics in a vessel in a living body. The external fluid-filled catheter pressure transducer includes an inverted sensor bonded to a hollow carrier so that measuring occurs on the inside of the carrier. The fluid-filled catheter pressure transducer allows pressure measurements to be taken in vessels smaller than 1 mm in diameter. A method for manufacturing an external fluid-filled catheter pressure transducer describes connecting sections of tubing (semi-rigid and flexible) to an inverted sensor module, and providing a reference port for the inverted sensor module.

Abstract: The invention provides a method and system for reconstructing a high-fidelity pressure waveform with a balloon catheter used in a heart. First, a balloon catheter having an air line is inserted into the aorta of the heart. The air line is then closed and sufficient air is introduced in order to equalize the pressure in the balloon catheter and the aorta. The AC components of the aortic pressure and the mean aortic pressure are detected separately and then added to form a high-fidelity pressure waveform. The high fidelity pressure waveform may be displayed on an oscilloscope, a patient monitor, or other suitable display.

Abstract: The present invention relates to a pressure sensor module for use in catheters having a pressure sensor operable to provide a signal representative of pressure. The pressure sensor includes a sensing side and a pressure reference side. At least one signal transmission media is coupled to the sensor for transmitting the signal representative of pressure. A convex-shaped carrier is provided having a slot formed to expose the sensing side of the sensor. The convex-shaped carrier is adapted for receiving the sensor such that the sensing side of the sensor is adjacent the slot. A bonding material is provided for mounting the sensor to the carrier. The pressure sensing module provides ease of installation and manufacture because the module may easily be bonded and installed within a catheter.

Abstract: A device that contemplates a unique and advantageous reduced size catheter tip measurement device. By using a bottom support member and a thin outer insulating layer, rather than a tubular metal casing, to support and isolate the electrical measurement sensor, the present invention drastically reduces feature size possible with current structures for catheter tip measurement devices. More specifically, the device contemplates a reduced size catheter tip pressure transducer device. The device includes a catheter body that has a support member attached to its distal tip. The support member has a support surface for a semiconductor pressures sensor that provides mechanical stability to the pressure sensor. The exposed electrical and metal areas of the device are insulated from surrounding tissues and fluids by an outer insulating layer, which is preferably a polyimide sleeve.

Abstract: A pulse transducer is disclosed having a pressure sensor for detecting pulse pressure and a velocity sensor for simultaneously detecting pulse velocity in blood vessels. The present invention allows reproduction of pulse pressure and velocity waveforms. The present invention combines a conventional applanation tonometer with a mounted velocity sensor, such as a Doppler crystal. The velocity sensor is placed proximate to the pressure sensor to allow simultaneous detection of pulse velocity, in real time, at substantially the same location as the pulse pressure measurement. The sensing direction of the velocity sensor may be at an angle with respect to the sensing direction of the pressure sensor. The present invention may be applied vertically to a vessel for proper applanation, while ultrasound, traveling across the vessel, may be used to detect a major component of the velocity.

Abstract: The invention relates to catheters having a distally-mounted balloon and pressure sensor and to methods of placing such catheters within physiological vessels. Catheters have a central lumen extending through the catheter and a pressure sensor which lies within the distal portion of the central lumen but does not occlude the lumen. Additionally, catheters may have a Doppler velocity measurement sensor affixed to the distal end of the catheter for measuring fluid velocity distal to the catheter. Inflation of the balloon prevents vessel wall contact with other portions of the catheter tip during flow-directed placement of the catheter. During catheter placement to obtain a wedge pressure, the balloon is inflated until fluid velocity detected with the Doppler sensor is substantially zero.

Abstract: A method and assembly is provided which allows measurement of intracranial fluid charateristics at the intracranial region of the brain. The invention contemplates a method of implanting a ventricular catheter having one end residing in the ventricular region and the other end exiting the cranial region at a distal location. A grooved needle allows placement of a transducer tipped catheter and rerouting of both the ventricular, in-dwelling catheter and the transducer tipped catheter placed within the in-dwelling catheter. Intracranial fluid characteristics are monitored by an electrically coupled distal monitor. Further, access to the intracranial fluid is also provided to allow either short-term or long-term withdrawal or injection of intracranial fluid.

Abstract: A method and assembly is provided which allows measurement of intracranial fluid characteristics at the intracranial region of the brain. The invention contemplates a method of implanting a ventricular catheter having one end residing in the ventricular region and the other end exiting the cranial region at a distal location. A grooved needle allows placement of a transducer tipped catheter and rerouting of both the ventricular, in-dwelling catheter and the transducer tipped catheter placed within the in-dwelling catheter. Intracranial fluid characteristics are monitored by an electrically coupled distal monitor. Further, access to the intracranial fluid is also provided to allow either short-term or long-term withdrawal or injection of intracranial fluid.

Abstract: A method and system for introducing one or more devices into a biological fluid vessel. The system includes a device having a coupling structure comprising a pair of spaced-apart fingers adapted for receiving a guidewire therebetween. Preferably, the system includes a guidewire having a constricted fitting region at its proximal end where the coupling structure may be easily connected to the guidewire. In one use, the method is used in coronary angioplasty to diagnose and treat stenosis across a coronary valve or other vessel in the coronary arterial tree. In this method, a guiding catheter is percutaneously inserted with its distal end proximate the ostium. A guidewire is inserted through the guiding catheter and subselectively positioned in a region of interest in the coronary arterial tree. Multiple devices may be coupled to the guidewire in accordance with the present invention and then threaded down the guidewire and positioned in the region of interest.