Low-cost and portable impedance plethysmography system for the simultaneous detection of respiratory and heart activities
Impedance plethysmography is a technique that allows monitoring changes in the volume of specific tissues or organs inside the human body, through the measurement of variations in the bio-impedance between electrodes placed on the body surface. One of its best-known applications is the monitoring of respiratory activity based on trans-thoracic impedance measurements. Provided the measurement system has enough sensitivity, trans-thoracic impedance can also allow the detection of heartbeats, thus adding cardiac activity monitoring capabilities.