The Multiple Inert Gas Elimination Technique 50 years later: Lessons Learned

The Multiple Inert Gas Elimination Technique (MIGET) was developed in the early 1970’s to measure the way in which pulmonary ventilation (Va) and blood flow (Q) are distributed one to the other. It is based on the elimination of six foreign inert gases simultaneously infused intravenously, with computer analysis of their elimination pattern to deduce, qualitatively and quantitatively, the shape of the responsible Va/Q distribution. After summarising MIGET’s physiological basis, this article presents the key observations made using MIGET over many years in health and in three chronic lung diseases – chronic obstructive pulmonary disease (COPD), bronchial asthma and interstitial lung disease. While significantly advancing our understanding of the pathophysiology of these diseases, the findings have led to many still unanswered questions of clinical significance in each case. These questions are also presented and discussed.