Detection of drastic blood pressure changes

An alarm apparatus for predicting a rapid blood pressure decrease in a patient undergoing extracorporeal blood treatment, the apparatus comprising:

• an input interface configured to receive a basic electrocardiogram signal of the patient;
• a primary beat morphology analysis unit configured to:
• discriminate a first heartbeat and a second heartbeat in the basic electrocardiogram signal, said basic electrocardiogram signal having a plurality of signal segments,
• classify each of the discriminated first heartbeat and the second heartbeat into one out of at least two different beat categories from the group of a beat whose morphology is typical for the patient, a ventricular ectopic beat representing a beat whose morphology differs substantially from a normal sinus beat, a supraventricular ectopic beat representing a beat whose morphology differs from a normal sinus beat with respect to P-wave morphology, and a prolonged RR-interval, to subsequently process a signal that estimates the onset of a rapid blood pressure decrease,
• associate each of the plurality of signal segments of the basic electrocardiogram signal with event-type data reflecting one of said at least two different beat categories represented by the signal during that segment, the event-type data and the basic electrocardiogram signal together forming an enhanced electrocardiogram signal, and
• determine a number of secondary signal analyses to be performed in respect of the basic electrocardiogram signal;
• a bank of secondary analysis units configured to:
• receive and use the enhanced electrocardiogram signal to perform at least two different types of the determined secondary signal analyses in response to control instructions from the primary beat morphology analysis unit, and for each analysis performed, produce a respective test signal;
• and
• an alarm generating unit configured to:
• receive the test signals,
• investigate whether any of the test signals fulfill at least one alarm criterion, and if so,
• trigger an alarm signal indicative of an estimated rapid blood pressure decrease.