AUTOMATIC METHOD FOR MEASURING AND PROCESSING BLOOD PRESSURE Russian patent published in 2016 - IPC A61B5/215 G06F19/00 

FIELD: medicine.

SUBSTANCE: group of inventions refers to medicine. An automatic method for blood pressure signal processing is implemented by means of an automatic device for blood pressure signal processing, which comprises a processing unit. That involves A. sampling a recorded pressure signal P(t) for one or more cardiac contractions. Each cardiac contraction starts at the initial moment coinciding with one of initial points of diastolic pressure, and finishes at the final moment coinciding with the following point of diastolic pressure, and contains a dicrotic point. Each contraction comprises a systolic phase continuing from the initial diastolic point to dicrotic point; B. analysing and identifying the morphology of the pressure signal P(t) sample automatically for each cardiac contraction. A pressure moment and value are determined for one or more characteristic pressure signal P(t) points specified in a group containing: an initial point of diastolic pressure, a point of systolic pressure, a dicrotic point and one or more resonant points, each of which coincides with the moment, when the second derivative d²P/dt² of the pressure signal P(t) has a local maximum. At least one characteristic pressure signal P(t) point belongs to a systolic phase of the cardiac contraction of interest and differs from the initial point of diastolic pressure. C. determining an energy efficiency RES for each cardiac contraction is ensured by C1. measuring a direct dynamic impedance Z_{d_D}(t) for each of one or more characteristic points belonging to the systolic phase of the cardiac contraction of interest and different from the initial point of diastolic pressure. The direct dynamic impedance Z_{d_D}(t) equals to a relation of the pressure signal P(t) in the characteristic point to a period of time from the initial point of the cardiac contraction of interest to the moment of the above characteristic point. A direct pressure wave impedance Z_D is calculated by deriving a reverse-sign sum of the direct dynamic impedances Z_{d_D}(t) pre-ordered in accordance the moments starting from the initial point of the cardiac contraction of interest to the moment of the dicrotic point. The first mechanical dynamic impedance Z_{d_D}(t) in accordance with the moment pre-order is taken with a positive sign. C2. A reflected dynamic impedance Z_{d_R}(t) is determined for each of one or more characteristic points. The reflected dynamic impedance Z_{d_D}(t) equals to a relation of the pressure signal P(t) in the characteristic point to a period of time from the final point of the cardiac contraction of interest to the moment of the characteristic point. A reflected pressure wave impedance Z_R is calculated by deriving a reverse-sign sum of the reflected dynamic impedances Z_{d_R}(t) post-ordered in accordance the moments starting from the final point to the initial point of the cardiac contraction of interest. The first reflected dynamic impedance Z_{d_R}(t) in accordance with the moment post-order is taken with a positive sign. C3. The energy efficiency RES is described as a relation of the direct wave impedance Z_D to the reflected wave impedance Z_R: RES = Z_D/Z_R. D. For the energy efficiency RES determined at the stage C, it needs verifying if the first derivative dP/dt of the pressure signal P(t) is sure to be less than the first maximum threshold T_d throughout the duration of the cardiac contraction of interest, and the second derivative d²P/dt² of the pressure signal P(t) is sure to be less than the second maximum threshold T_d2 throughout the duration of the cardiac contraction of interest. If the verification procedure appears to give a negative result, the stage E is supposed to be performed, whereas the verification with a positive result is followed by the stage F. E. A low-pass filter frequency cut-off is specified in accordance with the energy efficiency RES determined at the stage C, first derivative dP/dt and second derivative dP/dt of the pressure signal P(t). The low-pass filter is applied to the pressure signal P(t) to produce thereby a new pressure signal sample, and the previous stages are performed starting with B. F. The pressure signal P(t) which was the last to processed through the stage B is presented.

EFFECT: achieving higher reliability of the blood pressure measurement ensured by dynamic adjustment to blood pressure variability.

19 cl, 7 dwg