PMC9720332_01
A and 1B: Diaphragm ultrasound in a patient with myofibrillar myopathy associated with chronic respiratory insufficiency 1A: right diaphragm paradoxical sniff TM motion TM: time movement, 1B: major utilization of the right parasternal intercostal muscle at rest breathing, The end expiratory thickness parasternal inter costal muscle is at 5.6 mm. The end inspiratory thickness of the parasternal intercostal muscle is at 7.9mm; the thickening fraction of the parasternal intercostal muscle (TFic) is at 41%.
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Diaphragm ultrasound revealed significant diaphragm dysfunction with paradoxical ultrasound sniff diaphragm motion (-7 mm for the right hemi diaphragm and -14 mm for the left hemi diaphragm) (Fig. 1A). We used also ultrasound to assess parasternal muscle by the measurement of the parasternal intercostal muscle TFic, that is calculated from the measurement of parasternal intercostal thickness end expiratory and parasternal intercostal thickness end inspiratory using this formula: parasternal TFic = (end inspiratory parasternal intercostal thickness - end expiratory para sternal intercostal thickness)/end expiratory parasternal intercostal thickness (Fig. 1B). Ultrasound found a higher right parasternal intercostal muscle solicitation at rest breathing (5.6 mm at expiratory/7.9 mm at inspiration) with a parasternal intercostal muscle thickening fraction at 41% (Fig. 1B).To optimize ventilation, noninvasive ventilation settings were modified with an increase of the inspiratory positive airway pressure level.