Color Spectrographic Analysis of Respiratory Sounds: A Promising Technology for Respiratory Monitoring

Abstract

* Address correspondence to this author at the Department of General Anesthesiology, Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA, E-mail: djdoyle@hotmail.com movements as well as observing signs, such as nasal flaring, or the use of the accessory muscles of respiration. Later, with the invention of stethoscope, simple acoustical methods of respiratory assessment became available to the clinical community. With the subsequent invention of electronic amplification, a variety of new technologies became available, including respiratory monitoring belts placed on the chest and abdomen [6 9], nasal pressure methods [10, 11], nasal / oral thermistor methods [12, 13] (the thermistor warms up with expired gases), nasal / oral capnography [14, 15], extraction of respiratory information from the photoplethysmograph signal [16, 17], and electrical impedance methods based on a small injected electrical current [18, 19].