| Abstract | A digital computer program for the study of lung mechanics which will be used to evaluate a respirator control scheme has been developed and tested. Seventeen patients were studied; 8 patients who underwent cardiac surgery demonstrated vital capacity decreases to 35 per cent of pre-operative, compliance decreases to 60 per cent, and resistance increases to 180 per cent. Seven patients who underwent abdominal surgery showed only a decrease in vital capacity. Three patients who had pulmonary resections showed changes similar to, but more severe than, the cardiac gruop. The monitoring potential of this information is discussed, as is the incorporation of this information into the design, testing, and ultimately the logic of a respirator controller. A controller is described which makes basic adjustments in minute ventilation and dead space to achieve controlled ventilation at normal arterial PCO2's. |