Method for determining blood pressure in a blood vessel and device for carrying out said method

1. A method for determining blood pressure in a blood vessel, comprising the steps of:

determining a pulse wave transit time using at least two sensors arranged at a defined distance from one another;

determining the blood pressure from a change in the pulse wave transit time by a calibration based on a signal that is synchronous with pulse rate and without use of any further signal that is in proportion to the flow velocity.

2. The method in accordance with claim 1 , wherein the calibration comprises calibrating the blood pressure determination using a clamping blood pressure measurement.

3. The method in accordance with claim 1 , wherein the step of determining a pulse wave transit time is performed multiple times and the calibration is performed after multiple determinations of the pulse wave transit time.

4. The method in accordance with claim 3 wherein, if no clamping pressure measurement is performed, a holding clamping pressure is applied by means of a pressure cuff incorporating the at least two sensors.

5. The method in accordance with claim 1 , wherein:

light pulses are emitted in a direction of the blood vessel using an illuminant of the at least two sensors; and

a portion of the light pulses reflected by blood in the blood vessel and/or a portion transmitted by the blood in the blood vessel is detected using a detector of the at least two sensors during a light detection.

6. The method in accordance with claim 5 , wherein a time offset between an activation of the at least two sensors is controlled so that similar relative light detection measurement readings are achieved, which essentially show a same place in a comparable light detection measurement value trends in regard to a light detection measurement curve form.

7. The method in accordance with claim 6 , wherein the time offset is determined based on characteristic values of light detection measurement trends.

8. The method in accordance with claim 7 , wherein minimum and/or maximum values and/or values at points of maximum increase in the light detection measurement are used as characteristic values.

9. The method in accordance with claim 5 , wherein a duration of the light pulses in comparison to phases of a drop in the light detection measurement readings is extended in phases of an increase in the light detection measurement readings.

10. The method in accordance with claim 9 , wherein multiple light detections per light pulse are performed in phases of an increase.

11. The method in accordance with claim 9 , wherein a duration of the light detection is extended in phases of an increase in the light detection measurement readings in comparison to the duration of the light detection in phases of a drop in the light detection measurement readings.

12. The method in accordance with claim 5 , wherein a number of the light pulses per heartbeat is kept constant, depending upon the heart rate.

13. The method in accordance with claim 1 , wherein in order to determine a light detection measurement reading, a maximum increase and/or a integral of the corresponding light detection measurement signal pattern is used.

14. A device for carrying out the method in accordance with claim 1 , comprising:

at least two sensors;

a pressure cuff for performing a clamping pressure measurement; and

an evaluation unit;

wherein the at least two sensors are integrated into the pressure cuff.

15. A device in accordance with claim 14 , wherein the sensors have a common detector or two detectors connected in parallel.

16. A device in accordance with claim 15 , wherein the detector of a sensor is located between an illuminant of said sensor and a central longitudinal axis of the pressure cuff.