ABSTRACT
El artículo presenta el desarrollo de una tarjeta de adquisición de datos (TAD) para uso biomédico. Este diseño forma parte de un sistema que permite realizar un análisis comparativo entre los sonidos cardiopulmonares (SC) y el electrocardiograma de alta definición (ECGAR). La TAD reportada digitaliza simultáneamente tres señales adquiridas. Los dos primeros canales digitalizan las señales correspondientes a las derivaciones dI y dIII del ECGAR. El tercer canal digitaliza la señal captada del SC. El instrumento consta de dos partes, una etapa de hardware para adquirir la señal y un software para la manipulación de datos en la computadora. El hardware está compuesto por un microcontrolador de alto rendimiento, una interfaz de comunicación con la computadora vía USB y los circuitos de seguridad eléctrica inherentes a un equipo médico. El software permite la adquisición de las señales transmitidas desde el hardware, su visualización gráfica y el almacenamiento de la información en una base de datos. Las pruebas de funcionamiento demostraron errores inferiores al 0,1 % en las mediciones de amplitud y no se registró perdida de información en la comunicación con la computadora
The paper reports the development of a data acquisition card (TAD) for biomedical use. This design is part of a system that allows a comparative analysis between cardiopulmonary sounds (SC) and the high-definition electrocardiogram (ECGAR). The reported TAD simultaneously digitizes three acquired signals. The channels 1 and 2 digitize the ECGAR signals corresponding to leads dI and dIII. The channel 3 digitizes to SC captured signal. The instrument consists of two parts, a hardware for acquire the signal and a software for data manipulation in the computer. The hardware consists of a high performance microcontroller, a USB communication interface with the computer and the electrical safety circuits inherent to medical equipment. The software allows the signals acquisition transmitted from the hardware, its graphic visualization and the information storage in a database. The performance tests showed errors less than 0.1 % in amplitude measurements and no loss of information in the communication with the computer
Subject(s)
Humans , Male , Female , Stethoscopes , Electrocardiography/instrumentation , Signal Processing, Computer-Assisted , Cardiovascular DiseasesABSTRACT
The purpose of this study was to assess the usefulness of the time-axis variable function of the digital stethoscope in teaching cardiac auscultation. The subjects were 61 fifth-year medical students. The effectiveness of the time-axis variable function of the digital stethoscope for cardiac auscultation was assessed with five representative heart sounds or murmurs. The students reported that auscultatory findings were clearer at half speed than at normal speed for the following sounds, in decreasing order of frequency: systolic murmur following a systolic click, splitting of the second heart sound, systolic ejection murmur, and the third heart sound. In contrast, students frequently reported that auscultatory findings were clearer at normal speed for systolic regurgitation murmur. We suggest that the time-axis variable function is useful for improving auscultatory ability and would be particularly effective for helping students identify and understand the temporal relation of sequential heart sounds or of multicomponent murmurs.