Method for operating a blood pressure measuring apparatus, and apparatus for carrying out the method

1 . A method for operating a blood pressure measuring apparatus comprising the following method steps:

applying the blood pressure measuring apparatus to a measuring point on the body, wherein the blood pressure measuring apparatus contains a pressure measuring unit and a pressure unit;

initialising the blood pressure measuring apparatus by carrying out a reference measurement and determining person-specific initialisation parameters;

storing the person-specific initialisation parameters in a memory and control unit;

performing at least one blood pressure measurement in the presence of a counter pressure through the pressure unit in a sub-systolic range;

maintaining the counter pressure within a sub-systolic plateau phase for a predetermined duration and registering first temporal blood pressure curve data during the predetermined duration;

converting the registered first temporal blood pressure curve data into temporal arterial blood pressure data via the initialisation parameters,

wherein

the initialisation is carried out by performing the reference measurement with the following steps:

applying a measurement pressure to the blood pressure measuring apparatus in a defined pressure range;

changing in a defined way the measurement pressure from the blood pressure measuring apparatus and registering second temporal pressure curve data in the control and memory unit;

extracting an oscillating pulse component from the second temporal pressure curve in conjunction with a storing of a series of data regarding individual pulse waves in the control and memory unit;

performing a signal analysis of the individual pulse waves and a data comparison with a pulse wave signal model by the control and memory unit;

determining a first person-specific transfer function and coefficients thereof from the data comparison and storing the determined transfer function as one of the person-specific initialisation parameters in the control and memory unit,

wherein

after the initialisation and the determination of the coefficients of the first transfer function,

a second transfer function Hk(jω) is determined for a constant cuff pressure using the coefficients known from the initialization; and

an arterial pulse wave is calculated from an oscillating signal component of a sub-systolic plateau measurement using an oscillometric sub-systolic plateau measurement and the second transfer function Hk(jω) for constant cuff pressure associated with constant plateau pressure; and

wherein

the signal analysis of the individual pulse waves is performed with the following steps:

evaluating a form of each of the individual pulse waves and classifying each of the individual pulse waves in question in an evaluation unit and storing each of the individual pulse waves in an internal memory;

assembling and transforming pulse waves from at least one classification into the pulse wave signal model reproducing features of the arterial pulse wave; and

adapting measured pulse wave curves to the at least one pulse wave signal model and determining at least one specific transfer function for the particular pulse wave signal model.

2 . The method according to claim 1 ,

wherein

a validation of the person-specific transfer function is carried out, wherein second blood pressure curve data determined and stored during a validation blood pressure measurement at a given counter pressure are compared with given reference parameters.

3 . The method according to claim 1 ,

wherein

the at least one blood pressure measurement in the sub-systolic range includes conversion of measured temporal blood pressure values into arterial blood pressure values in the control and memory unit based on an inversion of the person-specific transfer function determined from the initialisation step.

4 . The method according to claim 1 ,

wherein

the at least one blood pressure measurement in the sub-systolic range includes carrying out an iterated model-based blood pressure determination in the control and memory unit, wherein a deviation-minimising adaptation of parameters of the pulse wave signal model to the oscillating signal component of the measured blood pressure is performed via a signal transformation.

5 . The method according to claim 1 ,

wherein

in a validation of the initialisation parameters, a model-based blood pressure determination is carried out in the sub-systolic range and is compared with the pulse wave signal model and a signal curve from the reference measurement, wherein an initialisation result is compared with the provided initialisation parameters.

6 . The method according to claim 1 ,

wherein

the reference measurement is carried out by an invasive blood pressure measuring catheter, located in a blood vessel, wherein a time curve of blood pressure is determined and is compared with a temporal pressure curve determined in parallel at the blood pressure measuring apparatus in order to determine the at least one specific transfer function for the pulse wave signal model, wherein the pulse wave signal model is scaled so that a resulting calculated pulse wave signal approximates the arterial pulse wave as accurately as possible.

7 . The method according to claim 1 ,

wherein

for the initialisation and/or the at least one blood pressure measurement, an inflatable pressure cuff or a combination of a pressure cuff and a garment exerting a constant sub-systolic pressure is used as the pressure unit of the blood pressure measuring apparatus.

8 . The method according to claim 1 ,

wherein

an inflatable pressure cuff in combination with an optical or electromagnetic sensor is used as the pressure unit of the blood pressure measuring apparatus, wherein the inflatable pressure cuff is used for carrying out the reference measurement and the sensor is used for the at least one blood pressure measurement in the sub-systolic range.