Noise-resistant technique for recording pulse waves and measuring cardiac intervals to improve the accuracy of operational assessment of the patient’s functional state during a magnetic therapy session

Modern non-invasive means of quickly assessing the functional state of a patient, widely used in clinical practice and especially in intensive care units, are based on the method of variational pulsometry, where the sources of information are the pulse wave signal (photoplethysmogram signal) and the duration of cardio intervals. However, due to a number of reasons caused by the action of various interferences, artifacts and the nature of the change in the photoplethysmogram signal over time, the measured values of the durations of cardiac intervals may be distorted and unreliable. These factors reduce the diagnostic accuracy of the method. To develop a methodology and hardware and software that work effectively in conditions of all kinds of interference, increasing the accuracy of recording the photoplethysmogram signal and measuring the duration of cardiac intervals. A method and technical means are proposed that ensure reliable collection of a pulse wave signal from a patient during a magnetic therapy session, its conversion into code, processing, noise-resistant registration of signal implementations on each cardiac cycle and measurement of their durations, which are used for prompt assessment of the patient’s current functional state using a number of calculated diagnostic indicators. Physical modeling of the pulse wave signal and simulation of possible random interference and artifacts made it possible to determine the potential noise immunity of the proposed technique and estimate the errors in measuring the durations of cardiac intervals. The introduction of the developed methodology and hardware and software into the “Multimag” chronomagnetic therapy complex will make it possible to significantly increase the diagnostic accuracy of the operational determination of the patient’s functional state during a magnetic therapy session, and accordingly increase the effectiveness of treatment.