Blood gas analysis in non invasive respiratory care units

Lung diseases needing a fast, pratical, and critical interpretation of blood gas data and acid-base disorders are usual in non invasive respiratory care units. The increasing development of non invasive mechanical ventilation forces the clinician to have a scientific background first to approach then to explain and finally to manage respiratory and metabolic problems of diffuse lung diseases such as COPD, acute pulmonary edema, pulmonary fibrosis and ALI/ARDS. Moreover patients undergoing lung transplantation and lung volume reduction need careful monitoring of acidosis and alkalosis, oxygen status of arterial blood and hypercapnia, and knowledge of abnormal gas exchange mechanisms to improve the prognosis after surgery. This review tries to give a basic and, if possible, easy pathophysiologic approach to an hystorically complex topic: the interpretation of blood gases and acid base mechanisms.