Blood gas measurements in clinical practice.

UNTIL recent years methods of blood gas measurement have been difficult and they were therefore not widely available. Their possible value in routine clinical practice was consequently largely unknown and unexplored, and many clinicians have forgotten their basic knowledge of oxygen and carbon dioxide physiology. The sequence is now in reverse. There are easy methods which could be widely available. Clinicians are learning their value in practice and in the process are relearning respiratory physiology. The aim of this article is to catalyse this chain reaction by indicating the most practicable methods and by describing the use of the measurements in practice. There is now no need for physicians to rely entirely on clinical judgment in assessing, for example, methods of treating respiratory depression in cases of poisoning. They would be unhappy without measurements of blood sugar in diabetic coma, urea in renal failure or sodium in adrenal failure. They are now entitled to require knowledge of the Pco2 in respiratory failure.