Breathing pattern and load compensatory responses in young scoliotic patients.

The breathing pattern and mouth occlusion pressure developed in 0.1 seconds (P0.1) were measured at rest in sixteen young scoliotic patients in whom the blood gases were within the normal limits. The patients exhibited rapid and shallow breathing. P0.1 was increased above normal, indicating a compensatory increase of neuromuscular inspiratory drive in the face of a stiffer respiratory system. P0.1 (% predicted) correlated positively with the angle of scoliosis. Both duration of inspiration and inspiratory duty cycle correlated negatively with angle of scoliosis and P0.1 (% predicted). On theoretical grounds we show that these changes in breathing pattern are beneficial, both in terms of reducing the energy cost of breathing and preventing the development of inspiratory muscle fatigue.