No abstract

Sixteen comparisons (3 in females, 13 in males) were made of pulmonary function tests in the standing, seated and supine positions. The significant changes were an increase in tidal volume on standing from either the seated or supine positions, but no change on lying (supine) from the seated position; a progressive decrease in the expiratory reserve volume on going from the standing to the seated to the supine positions; an increase in the inspiratory capacity on lying supine from either seated or standing positions, but no significant change on standing from the seated position; and a suggestion of increased turbulence (k2 term) on passing from the seated to either of the other positions. The other functions tested (minute volume, vital capacity, maximal pressures, elastance, resistance, maximal flows) did not change significantly. The variation and progression of week-to-week changes are described for five paralyzed patients after poliomyelitis and three normal subjects studied over a 2–3 month period. The changes occurring in five normal subjects studied at about 9-month intervals for periods of 9–39 months are also described. Submitted on August 17, 1959

In a group of 13 supine, anesthetized cats initial measurement was made of respiratory elastance, total resistance by sinusoidal pressure, total resistance, k1 and k2 and their ratio of change from breath to breath, the natural frequency, damping factor and mass factor or inertance, and the functional residual capacity (FRC) and tissue resistance. Comparison was then made with the value obtained by remeasurement in the same cat after a) control operation of mid-line abdominal incision; b) incisions eliminating the effects of the abdominal muscles (mid-line vertical plus transverse incision extended to back); c) evisceration of gastrointestinal tract and spleen and d) evisceration plus hepatectomy. The abdominal response was found to be mainly a surface wave response (at a speed of about 150 cm/sec.) above the natural frequency. The abdominal muscles impose a steady force, more like a weight than a spring, which decreases the FRC. The liver contributes significantly to the mass factor and natural frequency, but the viscera do not. About half the tissue resistance consists of a resistance within the abdomen to respiratory movements; since nearly half the total resistance is tissue resistance, this is nearly one fourth the total resistance to respiration. Submitted on June 2, 1958