Associate Editor: David Feller-Kopman
Sonographic assessment of changes in diaphragmatic kinetics induced by inspiratory resistive loading
Article first published online: 21 MAR 2013
© 2013 The Authors. Respirology © 2013 Asian Pacific Society of Respirology
Volume 18, Issue 3, pages 468–473, April 2013
How to Cite
Soilemezi, E., Tsagourias, M., Talias, M. A., Soteriades, E. S., Makrakis, V., Zakynthinos, E. and Matamis, D. (2013), Sonographic assessment of changes in diaphragmatic kinetics induced by inspiratory resistive loading. Respirology, 18: 468–473. doi: 10.1111/resp.12011
- Issue published online: 21 MAR 2013
- Article first published online: 21 MAR 2013
- Accepted manuscript online: 5 NOV 2012 07:07AM EST
- Manuscript Accepted: 10 SEP 2012
- Manuscript Revised: 31 AUG 2012
- Manuscript Received: 1 JUL 2012
- airway resistance;
- respiratory mechanics;
- respiratory muscle;
Background and objective
Diaphragmatic breathing patterns under resistive loading remain poorly documented. To our knowledge, this is the first study assessing diaphragmatic motion under conditions of inspiratory resistive loading with the use of sonography.
We assessed diaphragmatic motion during inspiratory resistive loading in 40 healthy volunteers using M-mode sonography. In phase I of the study, sonography was performed during normal quiet breathing without respiratory loading. In phase II, sonography was performed after application of a nose clip and connection of the subjects to a pneumotachograph through a mouth piece. In phase III, the participants were assessed while subjected to inspiratory resistive loading of 50 cm H2O/L/s.
Compared with baseline, the application of a mouth piece and nose clip induced a significant increase in diaphragmatic excursion (from 1.7 to 2.3 cm, P < 0.001) and a decrease in respiratory rate (from 13.4 to 12.2, P < 0.01). Inspiratory resistive loading induced a further decrease in respiratory rate (from 12.2 to 8.0, P < 0.01) and a decrease in diaphragmatic velocity contraction (from 1.2 to 0.8 cm/s, P < 0.01), and also an increase in tidal volume (from 795 to 904 mL, P < 0.01); diaphragmatic excursion, however, did not change significantly.
Inspiratory resistive loading induced significant changes in diaphragmatic contraction pattern, which mainly consisted of decreased velocity of diaphragmatic displacement with no change in diaphragmatic excursion. Tidal volume, increased significantly; the increase in tidal volume, along with the unchanged diaphragmatic excursion, provides sonographic evidence of increased recruitment of extradiaphragmatic muscles under inspiratory resistive loading.