Apparatus for determining an indicator representative for a physiological parameter

A method for determining an indicator that is representative for a physiological parameter, wherein the method comprises:

• providing) a measured pulse signal of a patient over a time period corresponding to a plurality of subsequent respiratory cycles of the patient by a pulse signal provider, wherein the pulse signal is a pressure signal that has been measured by using a pressure cuff with a pressure sensor being in contact with the outer skin of the patient, wherein pressure applied to the patient by the pressure cuff is increased or decreased, while the pressure sensor measures the pressure signal on the outer skin of the patient, and wherein the measured pressure is indicative of blood pulsations,
• carrying out a determination procedure adapted to determine an indicator that is representative for a physiological parameter based on the provided pulse signal by an indicator determiner, wherein the determination procedure includes a) determining a respiratory pulse variation signal (r0) corresponding to pulse variations caused by ventilation or respiration induced heart-lung interaction based on the provided measured pulse signal, b) determining a systolic part of the respiratory pulse variation signal, which corresponds to a time period in which the increasing or decreasing applied pressure passed the systolic arterial pressure of the patient and which therefore is prone to comprising an artifact, c) modifying the respiratory pulse variation signal such that the determined systolic part of the respiratory pulse variation signal is corrected and d) determining the indicator based on the measured pulse signal and the modified respiratory pulse variation signal.

A tangible non-transitory computer readable storage medium that stores a computer program, wherein the computer program, when executed by a processor, causes a computer apparatus to to carry out the steps of:

• providing a measured pulse signal of a patient over a time period corresponding to a plurality of subsequent respiratory cycles of the patient by a pulse signal provider, wherein the pulse signal is a pressure signal that has been measured by using a pressure cuff with a pressure sensor being in contact with the outer skin of the patient, wherein pressure applied to the patient by the pressure cuff is increased or decreased, while the pressure sensor measures the pressure signal on the outer skin of the patient, and wherein the measured pressure is indicative of blood pulsations,
• carrying out a determination procedure adapted to determine an indicator that is representative for a physiological parameter based on the provided pulse signal by an indicator determiner, wherein the determination procedure includes a) determining a respiratory pulse variation signal (r0) corresponding to pulse variations caused by ventilation or respiration induced heart-lung interaction based on the provided measured pulse signal, b) determining a systolic part of the respiratory pulse variation signal, which corresponds to a time period in which the increasing or decreasing applied pressure passed the systolic arterial pressure of the patient and which therefore is prone to comprising an artifact, c) modifying the respiratory pulse variation signal such that the determined systolic part of the respiratory pulse variation signal is corrected and d) determining the indicator based on the measured pulse signal and the modified respiratory pulse variation signal.