Oximetric and capnometric studies--aspects of natural and artificial ventilation

Methods and instrumentation of own design and their application to the measurement of oxygen and CO2 content in blood and respiration gases are discussed. Spectrophotometry, particularly double wavelength colorimetry using red light and IR light, applied to the measurement of oxygen blood saturation for in vitro examination and through an intravascular catheter for invasive in vivo study and by means of pulse oximetry for non-invasive in vivo examination are presented. The electrochemical methods applied to in vitro and in vivo measurement of oxygen in blood (amperometric method) and in respiration gases (amperometric and fuel cell methods) are discussed. The electrochemical Stow-Severinghaus method of CO2 tension measurement in blood and CO2 partial pressure in respiratory gases as well as the selective IR light (4.26 microm) absorption method and instruments of own design for CO2 measurements in respiratory gases are also discussed. The methods and instrumentation described are very important for monitoring respiratory and circulatory function, particularly during artificial ventilation and circulatory support.