The role of alveolar recruitment and de-recruitment in pressure-volume hysteresis in lungs

Abstract

Gil and Weibel (1972) have demonstrated the importance of alveolar recruitment at relatively low inflating pressures, which has also been noted by Klingele and Staub (1970). These findings are incorporated into a model of alveolar mechanics which presents a possible solution to the questions concerning the classical theory of PV hysteresis which are raised by the mercury filled lung and the Tween 20 rinsed lung experiments. A mathematical model was used to test the hypotheses and curves consistent with the experimental data are generated by a small computer. It is concluded that according to the model, the classical theory of PV hysteresis is valid under normal physiologic conditions but alveolar recruitment and de-recruitment become important factors in alveolar mechanics under conditions of alveolar instability.