Medición de gasto cardiaco para aplicaciones en docencia: comparación de dos tecnologías

Abstract

The Cardiac Output (CO) can be measured by using techniques like Electromagnetic Measurement, Dilution, Ultrasound, and Transthoracic Impedance (TIT). The TIT is a less invasive and cheap technique, and it is possible to use it for teaching application. Nowadays, the Biomedical Engineering Teaching Laboratories, at Universidad Autónoma Metropolitana-Iztapalapa, have two commercial technologies which carry out this kind of measurement by using the TIT, Nihon Kohden (NK) and Biopac Systems (BS). The purpose of this work was to compare both technologies in order to evaluate their utility for teaching application. To do this, the CO values and the operation procedures of both technologies were contrasted. The impedance changes, its first derivative, the ECG, and the PCG signals of five subjects were recorded using both technologies. Each subject executed six maneuvers, and the CO average value during each maneuver was calculated. Results showed that the CO values generated by both technologies were similar. BS is easier to operate than NK, and convenient for physiological applications where the main objective is to study the physiology related to CO phenomena. NK demands attention during its calibration and operation, but NK is very interesting for applications where the knowledge of the measurement instrument is the main objective.