There are various ways of determining whether a patient is suffering from hypotension (low blood pressure). One of those methods that incorporate the use of a electrocardiogram, during hemodialysis. This method is safe, thoroughly external and does not compromise the integrity of the body at any point. It works solely using the simple harmonic aspects of the ECG signal, and by detecting fluctuations in heart rate.

First, the ECG signal is separated into three processing blocks. The signal is preprocessed in the first block, where it undergoes baseline filtering, QRS detection, beat characterization and beat classification. The different classifications used in this case are ectopic beat, normal sinus beat, artifact and noise, and a cross correlation method is used to classify the beats into these categories.

The processed signal is fed to the following blocks, where it is respectively subjected to HRV (Heart Rate Variability) and EBC (Exhaled Breath Condensate) analyses, portraying two distinct and mutually inclusive mechanisms of cardiac activity. Application of EBC analysis is possible even in the presence of multiple ectopic beats, in which case HRV analysis is not possible.

Any deviations of blood pressure from normal can be determined from the results of these analyses.