A portable instrument for non-invasive monitoring of beat-by-beat cardiovascular haemodynamic parameters based on the volume-compensation and electrical-admittance method.

A new, portable instrument has been developed for simultaneous monitoring of blood pressure, cardiac output and other cardiovascular haemodynamic variables. The measurements are based on the volume-compensation method and the transthoracic electrical admittance method. The instrument is small and light and can be carried by the subject. The portable unit controls the measurement procedures, performs the blood pressure and cardiac output measurement, processes signals and stores almost 32,000 beats of time-series data in a fully automated manner. A conventional personal computer is used to initialize the measurement system, and to reproduce and evaluate the measurement data. The measurement system provides a means to evaluate in detail, without restriction, the subject's cardiovascular haemodynamic responses to daily physical activities as well as to various psycho-physiological stresses. The paper describes a new, portable, cardiovascular haemodynamic instrument and in-the-field test results. Twelve subjects are monitored for trials, 60-210 min, and fewer than 3% of the data in each trial are artifactual. Artefacts are due mainly to body movements.