Mechanical Properties of the Chest During Intermittent Positive-Pressure Respiration

The distribution of blood flow, oxygen consumption, and work output among the respiratory muscles during unobstructed hyperventilation.

“…Also, if it is asstumed that our estimate of 15.5% is lower than 19-25% efficiency maximum for skeletal mutscle duie to this unmeasured work on the chest wall and abdomen, then ouir estimate has failed to measture 18-38% of the work done by the respiratory muscles. This range correlates nicely with the range of previouis estimates of the percentage of respiratory work requiired to move the tissues of the thorax and abdomen, from 18-20% (35) to 34% (36).…”

“…Thus, the efficiency of the respiratory muscles (Table IV) (32). These studies have used the change in total body oxygen consumption (33)(34)(35)(36)(37)(38) as an index of the increase in respiratory muscle oxygen consumption needed for an increased work of breathing. Since the oxygen consumption of the respiratory muscles in normal subjects is only 1-3% of total body oxygen consumption (33) Our estimate of efficiency dturing CO2 rebreathing may be slightly low because in calculating oxygen constumption we have assumed for all mtuscles of r-espirattion a simiilar A-V A Co., to that of the diaplhra(rigm.…”

Expiratory Pressures and Air Flow During Speech

“…The excursions of the spirometer were recorded on the same kymograph. Howell and Peckett (1957) and Opie, Spalding, and Stott (1959) used a balloon 10 cm. long sited lower in the oesophagus to give a measure of intrapleural pressure; as discussed below, the size of the balloon and its position in the oesophagus are important.…”

The Effect of Intermittent Positive Pressure Breathing on the Lung Compliance and Intrapulmonary Mixing of Gases

“…Howell and Peckett (1957) also found that both the whole chest and lung compliances in anaesthetized and paralysed subjects, inflated by a positive pressure method, were less than they expected from the results obtained by other workers under normal pressure conditions. In the paretic patients studied by Opie, Spalding, and Stott (1959) the average lung compliance during intermittent positive pressure breathing was less than half that during spontaneous breathing.…”

“…In the paretic patients studied by Opie, Spalding, and Stott (1959) the average lung compliance during intermittent positive pressure breathing was less than half that during spontaneous breathing.…”