The relationship between diaphragmatic mobility and chest wall expansion in cerebral palsy

Abstract

Diaphragmatic muscle weakness is one of the significant causes of respiratory failure leading to morbidity and mortality among cerebral palsy (CP). Ultrasound (US) measurement of the diaphragm has been recently developed to measure the function of diaphragm in some respiratory diseases and neuromuscular conditions. Critometry has been applied widely in clinical practice as a chest wall mobility index including diaphragmatic expansion. The aim of this study was to examine the correlation between diaphragmatic mobility measured by ultrasound and chest wall expansion measured by critometry among children with CP. A predictive relationship might permit the use of critometry as a measurement of diaphragmatic mobility for CP. Eighteen spastic diplegia CP (age 12.72±2.27 years) were included into the study. M-Mode US (GE Healthcare LOGIQ V2, USA) was applied to assess diaphragmatic mobility with the following instrument settings; Convex probe 4.0 MHz, depth 18 centimetres, speed 14 seconds per screen. Chest wall expansion was measured at three levels (upper, lower and abdomen) using a tape measure. The results showed significant correlations between right diaphragmatic mobility and chest expansions at three levels (r=0.64, p=0.004 for upper chest, r=0.74, p=0.001 for lower chest and r=0.73, p=0.001 for abdomen). There were also significant correlations between left diaphragmatic mobility and chest expansions at three levels (r=0.53, p=0.023 for upper chest, r=0.57, p=0.014 for lower chest and r=0.63, p=0.005 for abdomen). These initial results indicate that critometry might be able to monitor changes of diaphragmatic function among CP, though a larger sample is needed to confirm it.