Sensors for monitoring blood gases in intensive care

Abstract

The partial pressure of oxygen in blood and the oxygen saturation of blood reflect the ability of the lungs to transport oxygen from inspired air into the bloodstream, in order to make oxygen available to the tissues. Blood gas analysis is now one of the most frequent hospital diagnostic procedures. The technique of analysing individual blood samples, however, only gives information at one point in time, a snapshot of what is happening. It is now known that large variations in these gas levels can occur over the course of a few minutes. Invasive and non-invasive techniques have become available in the last few years for continuously measuring the arterial gas levels in patients. Of these, the transcutaneous technique and, more recently, the technique of pulse oximetry are now used extensively in medicine. The author deals with the advantages and current limitations of these techniques and with some of the developments in sensor technology associated with these measurements.