Patent ID: 8831717

Claim:
An alarm apparatus for estimating a patient's propensity to suffer from symptomatic hypotension during extracorporeal blood treatment, the apparatus comprising: an output interface configured to generate an electromagnetic test signal, said electromagnetic test signal being configured to be fed to at least one transmitter electrode, said at least one transmitter electrode being configured to apply the test signal over a thoracic region of the patient; an input interface configured to receive a result signal via at least one receiver electrode on the patient's body, the result signal being produced in response to the electromagnetic test signal; and an analysis unit configured to determine a bio-impedance parameter based on the result signal, wherein the analysis unit comprises: a processing module configured to derive a test parameter based on the result signal, the test parameter expressing a fluid status of the thoracic region of the patient, a comparison module configured to test whether the test parameter fulfills an alarm criterion, and an alarm triggering module configured to cause an alarm signal to be generated if the alarm criterion is fulfilled, the electromagnetic test signal comprising at least two signal components with mutually different spectral properties, the input interface is adapted to receive a set of result signal components via the at least one receiver electrode, the set of result signal components being produced in response to the electromagnetic test signal, and the processing module is configured to derive the test parameter based on the set of result signal components.