Loading patent…
AssigneesDeutsches Herzzentrum Berlin, Medserv GmbH
InventorErnst Wellnhofer
Estimating the term…
Method for determining, monitoring and updating correction data for correcting measured value distortions and for calibrating liquid-filled transmission systems, via which signals from the patient detected in the body of a patient are transmitted to an external measured value receiver, in particular for invasive pressure measurements in cardiology, intensive care medicine and anaesthesia. The correction data are determined in the frequency range for each frequency from statistics of the signals from the patient measured at this frequency, in particular from the transmission function obtained from the signal from the patient. In the determination of the correction data, empirically checked assumptions about the corresponding statistics of undistorted signals from the patient and general properties of the transmission function are used.
Method for determining, monitoring and updating correction data for correcting measured value distortions caused by a liquid-filled transmission system and for calibrating the liquid-filled transmission system via which signals from the patient detected in the body of a patient are transmitted to an external measured value receiver, wherein the determination, monitoring and updating of the correction data can be carried out at a later time than the detection of the signals from the patient, in particular for invasive pressure measurements in cardiology, intensive care medicine and anaesthesia, characterised in that the correction data are determined in the frequency range using logarithmic transformations for each frequency from spectral statistics of the measured signals from the patient.
Method according to at least one of the preceding claims, characterised in that the segmenting of a pressure signal from the patient measured invasively by means of a catheter system for the invasive intra-arterial and/or intra-venal pressure measurement takes place heartbeat by heartbeat.
Method according to at least one of the preceding claims, characterised in that the segmentation takes place in signal from the patient segments which are suitable with respect to their length for a Fourier transformation.
Method according to at least one of the preceding claims, characterised by a trend adjustment of the segmentation of the signal from the patient or pressure signal from the patient.
Method according to at least one of the preceding claims, characterized by a multiplication of the segmented signal from the patient or pressure signal from the patient.
Method according to at least one of the preceding claims, characterised in that the signal model for a complex Fourier coefficient Si is
Method according to at least one of the preceding claims, characterised by an averaging of a plurality of consecutive determinations of the transmission function.
Method according to at least one of the preceding claims, characterised by a formal modelling of the transmission function determined consecutively as a space-state model.
Method according to at least one of the preceding claims, characterised by a coarsening of the spectral resolution by class formation for a plurality of frequency lines.
Method according to at least one of the preceding claims, characterised by a flattening interpolation of the determined transmission function and/or filtering of the transmission function by means of a low-pass filter.
Method according to at least one of the preceding claims, characterised by a direct adaptation to a second-order system with minimal deviation of the noisy transmission function determined from the statistics.
Method according to at least one of the preceding claims, characterised in that after a reduction in the noise in the statistics expected from the ratio of the actual statistics to the statistics in an undistorted signal from the patient or the difference between these functions after a logarithmic transformation of the determined transmission function, the damping coefficient and the resonance frequency or the amount of the transmission function are determined for the individual frequency lines.
Method according to at least one of the preceding claims, characterised in that the phase is calculated from the transmission function.
Method according to at least one of the preceding claims, characterised in that the complex inverse of this function is determined by computer from the amplitude and the phase of the transmission function determined in this way, the complex inverse serving as the correction data record for a correction in the frequency range, a segment by segment Fourier transformation of the measured signals from the patient taking place.
Dependencies are inferred from the claim text.