Another mechanism could be increased stimulation or irritation of chest wall and airway receptors generating an increase in Po.i. In this study, there was no statistically significant correlation between PaC02 and Po.i. Finally, it has been shown that respiratory muscle fatigue is less likely to occur with submaximal than with maximal Ve. If this phenomenon […]

Transdiaphragmatic pressure swings (APdi) during quiet breathing in patients with myotonic dystrophy are nearly three times that of normal seated subjects and are probably related to greater impedance to diaphragmatic motion caused either by chest wall stiffness or increase of tone in intercostal and abdominal wall muscles. Patients with muscular dystrophy and other paralytic neuromuscular […]

The increased Po.i relative to Ve measurements in the group with neuromuscular disease demonstrates that these two measurements are not comparable under these circumstances. In a study of eight normal volunteers undergoing C02 rebreathing during progressive curarization, Holle and coworkers also found that despite increasing muscle weakness and decreasing Ve, Po.i did not decrease, and […]

In fact, in the patients with neuromuscular disease, Po.i ranged between 0.72 and 3.59 cm H20, while Pimax at FRC averaged 43 percent of the control mean. Similar augmentation of the central drive to breathe has been documented in other chronic chest wall disorders without C02 retention, such as obesity. The breathing pattern of our […]

In addition, microatelectasis, by reducing the volume of gas remaining in the lungs at the end of a maximal expiration, may also tend to counter the increase in RV that would otherwise occur. In our study, the patients with neuromuscular disease demonstrated VC and ERV values that were, on the average, about one third of […]

In contrast, Ers in the patients with neuromuscular disease averaged 0.27 cmH20/percent VC, similar to the Ers of 0.19 cm H20/percent VC in seated conscious patients with neuromuscular disease whose cases were reported by Gibson et al. These findings imply that the increase in Ers observed in our patients with neuromuscular disease is proportional to […]

(c) Most Pmax values are recorded at one lung volume, usually FRC, and, as such, are regarded as quasi-static measurements during which flow rates are considered to be negligible. Because of flow- and volume-related losses in patients with neuromuscular disease, Pmax measurements may fail to detect an inability to cope with the increased ventilatory demands […]