Abstract
Background: Ultrasound measurements of abdominal muscle thickening fraction (TF) may be useful to monitor abdominal muscle activity and function.
Aims: To establish the reproducibility of measuring maximal TF (TFmax) of the abdominal muscles and to confirm the validity of using TFmax to assess abdominal muscle function.
Methods: In 20 healthy subjects, TF of right external oblique (EO), internal oblique (IO), transversus abdominis (TrA) and rectus abdominis (RA) were measured during maximal expiratory efforts against a closed airway and during coughing at functional residual capacity (FRC) and total lung capacity (TLC). The correlation between TF of each muscle and airway pressure during five forceful consecutive expiratory efforts against a closed airway of progressively increasing force was assessed. Reproducibility was assessed using a random effects model.
Results: IO TFmax measurements were moderately reproducible (mean 0.78±0.46 cm, reproducibility coefficient 0.42) but TFmax measurements were only poorly reproducible for all the other muscles. TF was correlated with expiratory airway pressure for RA (p=0.03), IO (p<0.001) and EO (p=0.03), but not TA (p=0.74). These correlations were not affected by lung volume (p>0.1 for all interactions). TFmax varied significantly between the 4 muscles (p<0.001). TFmax was not affected by lung volume or maneuver type, except for IO TFmax which was lower at TLC during maximal expiratory effort.
Conclusions: IO TFmax showed the highest reproducibility. TF of the EO, IO and RA was correlated to expiratory force generation. TFmax measured during coughing varied between muscles but was unaffected by lung volume.
Footnotes
Cite this article as: European Respiratory Journal 2019; 54: Suppl. 63, OA5367.
This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).
- Copyright ©the authors 2019