A Study of Acute Fatigue in the Canine Diaphragm with Documentation of Blood Flow, Oxygen Consumption, Work, and Efficiency of the Muscles of Respiration at Various Levels of Inspiratory Resistance

Abstract

We have designed an experimental model to investigate fatigue in the canine diaphragm under acute conditions when a large external resistive load is placed on inspiration. More specifically, we have attempted to determine whether or not the diaphragmatic blood supply limits the diaphragm's ability to perform heavy work. To accomplish this we have correlated measurements of diaphragmatic blood flow with inspiratory work, diaphragmatic oxygen consumption, and lactate production by the diaphragm. Since no previous work has been done in this particular area, this study was considered a preliminary investigation. In addition, we have employed the same model to study the recruitment of the various muscles of respiration as inspiratory work was increased, as well as estimating the mechanical efficiency of the respiratory muscles.