Apparatus and method for prediction of rapid symptomatic blood pressure decrease

A medical system configured to perform blood treatment of a subject, wherein the system comprises:

• a dialysis machine configured to perform extracorporeal blood treatment of the subject (P);
• a pulse recording apparatus configured to repeatedly register a pulse shape parameter in a peripheral body part of the subject wherein the pulse recording apparatus comprises a pulse oximetry instrument configured to register the pulse shape parameter based on light response variations in at least one blood vessel of the subject and
• a control unit configured to receive the pulse shape parameter, the control unit comprising a processing unit configured to:
• calculate, during a measurement period, a respective pulse magnitude measure based on each of a number of received pulse shape parameters,
• calculate a statistical dispersion measure from the pulse magnitude measures,
• investigate whether the statistical dispersion measure fulfils a decision criterion relative to a reference measure, and
• generate an output signal indicating a prediction of said rapid symptomatic blood pressure decrease in the subject.

A control unit for predicting rapid symptomatic blood pressure decrease in a subject, the control unit comprising:

• an input for receiving pulse shape parameters from a pulse recording apparatus configured means to repeatedly register a pulse shape parameter in a peripheral body part of the subject, wherein the pulse recording apparatus means comprises a pulse oximetry instrument configured to register the pulse shape parameter based on light response variations in at least one blood vessel of the subject, and
• a processing unit configured adapted to:
• calculate, during a measurement period, a respective pulse magnitude measure based on each of a number of received pulse shape parameters,
• calculate a statistical dispersion measure from the pulse magnitude measures,
• investigate whether the statistical dispersion measure fulfils a decision criterion relative to a reference measure, and
• generate an output signal indicating a prediction of said rapid symptomatic blood pressure decrease in the subject.

A method of predicting rapid symptomatic blood pressure decrease in a subject, the method comprising:

• registering a pulse shape parameter of a peripheral body part of the subject at repeated occasions,
• investigating, for each pulse shape parameter, whether or not the pulse shape parameter fulfils a decision criterion, and if so, causing an output signal to be generated,
• wherein the registering of the pulse shape parameter involves a pulse oximetry measurement, wherein the pulse shape parameter is determined based on light response variations in at least one blood vessel of the subject, and
• wherein the investigating comprises:
• calculating, during a measurement period, a respective pulse magnitude measure based on each of a number of received pulse shape parameters,
• calculating a statistical dispersion measure from the pulse magnitude measures, and
• investigating whether the statistical dispersion measure fulfils the decision criterion relative to a reference measure.

A computer readable medium comprising computer instructions which, when executed by a processor, cause the processor to predict rapid symptomatic blood pressure decrease in a subject by:

• registering a pulse shape parameter of a peripheral body part of the subject at repeated occasions,
• investigating, for each pulse shape parameter, whether or not the pulse shape parameter fulfils a decision criterion, and if so, causing an output signal to be generated,
• wherein the registering of the pulse shape parameter involves a pulse oximetry measurement, wherein the pulse shape parameter is determined based on light response variations in at least one blood vessel of the subject, and
• wherein the investigating comprises:
• calculating, during a measurement period, a respective pulse magnitude measure based on each of a number of received pulse shape parameters,
• calculating a statistical dispersion measure from the pulse magnitude measures, and
• investigating whether the statistical dispersion measure fulfils the decision criterion relative to a reference measure.

A monitoring arrangement for predicting rapid symptomatic blood pressure decrease in a subject, the monitoring arrangement comprising:

• means for registering a pulse shape parameter in respect of a peripheral body part of the subject at repeated occasions,
• means for investigating, for each pulse shape parameter, whether or not the pulse shape parameter fulfils a decision criterion, and
• means for causing, if the pulse shape parameter fulfils the decision criterion, an output signal to be generated,
• wherein means for registering is adapted to obtain the pulse shape parameter from a pulse oximetry instrument which is adapted configured to determine the pulse shape parameter based on light response variations in at least one blood vessel of the subject, and
• wherein the means for investigating comprises:
• means for calculating, during a measurement period, a respective pulse magnitude measure based on each of a number of received pulse shape parameters,
• means for calculating a statistical dispersion measure from the pulse magnitude measures (PM), and
• means for investigating whether the statistical dispersion measure fulfils a decision criterion relative to a reference measure.