Abstract: A catheter includes a longitudinally extending catheter tube to be inserted into a body. A plurality of sensing portions are arranged in the catheter tube for detecting at least two types of pressures acting on the catheter when inserted into the body. Each sensing portion is arranged along the longitudinal direction of the catheter tube. A silicone gel transmits the two types of pressures acting in the body to each sensing portion. The two types of pressures act on each sensing portion in a radial direction of the catheter tube by way of the silicone gel.

Abstract: An apparatus is in development which measures the blood outflow through the heart valves by means of the bolus thermodilution method and which from then on measures the continuous cardiac output, considering the formula of Gorlin and the measurement of the blood pressure in the compartments of the heart.

Abstract: Apparatus and method are provided for obtaining a measure of blood flow, and more specifically cardiac output, by analyzing blood temperature variations in the arterial tract. In a first embodiment, a lead carrying two closely spaced temperature sensors is positioned so that the sensors are in the atrial tract and produce temperature signals representative of small cyclical temperature variations of the blood outputted from the heart. The two signals have substantially similar patterns for each cardiac cycle, but the signals are separated by a short time (.increment.T) representative of the distance between the two sensors. The patterns are correlated to find .increment.T, from which cardiac output is calculated. In an alternate embodiment, a single blood temperature sensor is employed along with a sensor for determining cardiac contractions, and a measure of cardiac output is obtained by comparing the time difference between a feature of the blood temperature signal with the time of cardiac contraction.

Abstract: A stent or graft stent energized from an external power source is provided with one or more sensors to sense a parameter, producing a signal that is transmitted outside a vessel in which the stent is implanted. At least a portion of a body of the stent or an insulated electrical conductor comprises a plurality of turns that serve as an RF antenna. An expandable mesh or helical coils that form the stent body may serve as the antenna or it may comprise a separate insulated conductor. The RF antenna receives energy electromagnetically coupled to the antenna from an external (or implanted) coil and conveys a data signal corresponding to the parameter sensed by the sensor(s) on the stent or stent graft to a monitor disposed outside the patient's body. In one form of the invention, a plurality of conformal array transducers are used to produce and sense ultrasonic waves that are affected by a fluid flowing through a lumen of the stent. This transducer determines fluid flow or fluid velocity.

Abstract: A cardiac output measurement device volumetrically heating a predefined quantity of blood flowing through a heart by arbitrarily applying a containable energy field to the blood using a thermodilution catheter having an emitter that uniformly emits electromagnetic radiation. Blood temperature is measured at the pulmonary artery by a sensor that provides a signal representing the temperature of the mixed blood to a controller. The controller determines the flow rate, or cardiac output, by performing a heat balance analysis based upon the applied power and resultant blood temperature. The cardiac output measurement device includes a catheter having an emitter and, preferably, a temperature sensor located at its distal end. The catheter is coupled to a laser or other energy source capable of generating containable electromagnetic radiation, such as an ultraviolet or microwave energy source.

Abstract: An intravascular catheter system capable of mapping thermal variations in the temperature of athrosclerotic plaque, on the athrosclerotic plaque surface, and in the arterial wall of aneurysms and other vascular lesions of the human vasculature is provided. The catheter system incorporates a plurality of thermal sensors fixedly attached along the catheters multi-lumen flexible tubular member which is adapted for insertion into the human body. Optionally, the thermal mapping catheter of the present invention is combined with other features such as intravascular ultrasound, and localized drug delivery, to provide integrated device functions.

Abstract: A guide wire assembly comprises a tubular body having a distal end and an proximal end. At least a portion of the body comprises a single continuous helical spring to which one or more tubular electrodes are secured. The electrodes are insulated from the spring by means of an insulator. The electrodes can take a variety of forms, including conductive ribbons, longitudinally split conductive tubes, tubular sections, etc. The guide wire assembly may further include a variety of sensors, such as velocity sensors or temperature sensors. In order to allow flowable material to be passed to the distal end of the guide wire, the guide wire can include a catheter tube passable over the tubular body of the guide wire.

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 process and a device for determining the cerebral blood flow, and the intracerebral blood volume are described.After injection into the bloodstream of a predefined quantity of a double indicator, arterial and venous measurements of the indicator dilution curves resulting in the blood stream are carried out. A dye solution differing in its temperature from the body temperature serves as a double indicator, in which heat or cold constitute a highly diffusible indicator component, and dye, preferably indo cyanine green ICG, constitute an intravascular indicator component. The cerebral blood flow CBF is calculated from the ratio of a distribution coefficient .lambda..sub.therm of the highly diffusible indicator component therm between blood and cerebral tissue and the mean transit time mtt.sub.therm of the highly diffusible indicator component therm through the brain. The intracerebral blood volume ICBV is calculated from the product of cerebral blood flow CBF and the mean transit time mtt.sub.

Abstract: An instrument for achieving rapid hemostasis at the conclusion of a catheterization procedure comprising a hemostatic agent injection device for use with a conventional introducer sheath used to gain access to the blood vessel. The injection device includes an elongated tubular member having ejection ports proximate its distal end. A hub member is located on the proximal end of the tubular member and includes an elongated groove or track located in its surface with a transparent cover. The enclosed track is in fluid communication with the lumen extending through the tubular member. After the catheterization procedure, the instrument is inserted into the introducer sheath. Blood flows into the lumen of the device and into the enclosed track. The leading edge of the blood pulsates within the enclosed track, clearly indicating that the ports are located in the blood vessel and subjected to variations in blood pressure.

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: A thermodilution catheter having a heating filament which is fabricated so as to be thin and flexible enough to avoid contact with the patient's blood. The heating filament is either inserted in a preformed catheter lumen, incorporated into a wall of the catheter body itself, or wrapped around the catheter body wall and surrounded by an external sheath. Generally, the covering of the heating filament is minimally thin so as to allow the heat from the heating filament to be transferred to the surrounding blood and to minimally increase the overall cross-sectional area. Since the heating filament does not directly touch the patient's blood, the outer surface may be made smooth so as to prevent inducement of blood clots. In addition, the heating filament may be maintained at a safe temperature by forming the heating element of a flexible material having a high temperature coefficient of resistance, low thermal capacitance and high thermal conductivity.

Abstract: A system for keeping the surface temperature of an electric resistance-type heater element in a thermodilution catheter within safe physiological limits includes, in the preferred embodiment, a heater element core temperature monitor, a monitor for monitoring the power that is supplied to the heater element, and a surface temperature calculator for calculating the surface temperature of the heater element based on the core temperature, supplied power, and information representing the characteristics of the particular catheter under anticipated clinical conditions. A second aspect of the invention involves a system for determining the supply of power to the heater element based on the core temperature of the heater element. A third aspect of the invention involves a system readiness test for determining, in vivo, that the thermodilution catheter system is properly calibrated before the system is operational. Methods of operation for each of the above-referenced aspects of the invention are also disclosed.