The Multiple Inert Gas Elimination Technique (MIGET) is a complex mathematical model and experimental technique for understanding pulmonary gas exchange. Simpler mathematical models have been proposed which have a limited view when compared to MIGET, but may be applicable for use in clinical practice. This study examined the use of a simple model of gas exchange to describe MIGET retention and excretion data in seven pigs prior to and following lung damage caused by oleic acid infusion, and subsequently at different levels of PEEP. The simple model was found to give, on average, a good description of MIGET data, as evaluated by a ² test on the weighted residual sum of squares resulting from the model fit (p > 0.2). Values of the simple model's parameters (VD, shunt, and fA2), compared well with the similar MIGET parameters (VD, shunt, logSDQ, logSDV), giving values of bias and standard deviation on the differences between VD and shunt of 0.002 ± 0.002 l and 7.3 ± 2.1 % (% of shunt value) respectively. Values of fA2 correlated well with logSDQ (r² = 0.86) and logSDV (r² = 0.92). These results indicate that this simple model provides a good description of lung pathology following oleic acid infusion. It remains to be seen whether physiologically valid values of the simple model parameters can be obtained from clinical experiments varying FiO2. If so, this may indicate a role for simple models in the clinical interpretation of gas exchange.