Pressure sensing guidewires and methods for making and using pressure sensing guidewires are disclosed. An example pressure sensing guidewire may include a tubular member having a proximal region and a housing region. An optical pressure sensor may be disposed within the housing region. The optical pressure sensor may include a sensor body and a deflectable membrane coupled to the sensor body. The deflectable membrane may include a polymer. An optical fiber may be coupled to the sensor body and may extend proximally therefrom. A pressure equalization channel is formed in the optical fiber, the sensor body, or both.

A pulse transit time measuring apparatus according to one aspect includes a belt unit configured to be wrapped around a measurement site of a user, an electrocardiogram acquisition unit including electrodes provided at the belt unit and configured to acquire an electrocardiogram of the user by using the electrodes, a pulse wave signal acquisition unit including a pulse wave sensor provided at the belt unit, and configured to acquire a pulse wave signal representing a pulse wave of the user by using the pulse wave sensor, and a pulse transit time calculation unit configured to calculate a pulse transit time based on a time difference between a waveform characteristic point of the electrocardiogram and a waveform characteristic point of the pulse wave signal.

A method for monitoring a cardiovascular pressure in a patient may include storing, in a memory of an implantable medical device system and in association with each one or more different patient postures, a respective offset value for the cardiovascular pressure of the patient. The one or more offset values may be determined based on a distance between an implantable pressure sensing device and an anatomical structure of the patient, a location of the implantable pressure sensing device within the patient, or one or more dimensions an anatomical structure of the patient. The method further includes determining a measured value of the cardiovascular pressure and a posture of the patient when the value of the cardiovascular pressure was measured, selecting a stored offset value associated with the current patient posture, and determining an adjusted cardiovascular pressure value based on the selected offset value and the measured cardiovascular pressure value.

Method for determining a blood pressure value including the steps of: providing a pulsatility signal, determining a time-related feature and a normalized amplitude-related feature on the basis of the pulsatility signal; and calculating a blood pressure value on the basis of a blood pressure function depending on the time-related feature, the normalized amplitude-related feature and function parameters.

A flexible, passive pressure sensor includes three LC tank circuits. The first LC tank circuit is a pressure sensing LC tank circuit, having a capacitance that varies in response to changes in environmental pressure. The second and third LC tank circuits are reference LC tank circuits, having capacitances that are relatively constant over changes in environmental pressure. A measurement tool measures the resonant frequencies of the three LC tank circuits and then computes a pressure measurement that accounts for changes in resonant frequencies in the LC tank circuits due to environmental effects and deforming.

A system for determining a pulse wave velocity comprises a body lumen insertable device with an actuator for providing a pulse in the vicinity of a vessel wall and a sensor for sensing arrival of the pulse. A pulse wave velocity is obtained from the time difference between actuation of the actuator and sensing of the pulse. This system is used to create an artificial pulse which is transmitted along a vessel by a known distance before detection by a sensor.

A blood pressure measurement system comprising a pressure sensor guide wire comprising a pressure sensor located in a distal region of the pressure sensor guide wire that is configured to be inserted into a blood vessel of a human body and a transceiver unit communicatively coupled to the pressure sensor guide wire. The transceiver unit comprises a housing adapted to be used external to the human body, a sensor signal adapting circuitry configured to process pressure sensor values generated by the pressure sensor to create processed pressure sensor values, and a first transceiver configured to wirelessly transmit a signal representing the processed pressure sensor values using first, second, and third packets at first, second, and third frequencies.

A hemodynamic monitor implements an adaptive method that optimally estimates scaling and offset calibration parameters by using a computationally efficient, iterative online method to minimize the mean square error between a high bandwidth arterial pressure cardiac output (APCO) measurement generated by a first physiological sensor affixed to a patient and a relatively low bandwidth continuous cardiac output (CCO) measurement generated by a second physiological sensor also affixed to the patient. When calibration parameters are used to adjust an APCO measurement, the combined APCO/CCO estimate provided by the hemodynamic monitor has accuracy comparable to a CCO measurement, but also tracks cardiac output dynamical variations that are outside of the CCO algorithm bandwidth.

An apparatus for estimating bio-information includes a sensor configured to measure a bio-signal from an object, and a processor configured to obtain a feature based on the measured bio-signal, obtain a bio-information variation based on the obtained feature, obtain an adjustment coefficient based on the obtained bio-information variation, and estimate the bio-information by applying the obtained adjustment coefficient to the obtained bio-information variation.

A calibration system for a surgical instrument. The calibration system includes an actuator, such as a motor system and a flexible shaft. The calibration system also includes a surgical instrument actuatable by the actuator. The calibration system also include calibration data corresponding to the surgical instrument. A processor is configured to process the calibration data for determining a position of the surgical instrument. The calibration system may include a sensor configured to provide a signal corresponding to a movement of the actuator, the processor being further configured to process the signal for determining a position of the surgical instrument.