Although diaphragmatic motion is readily studied by ultrasonography, the procedure
remains poorly codified. The aim of this prospective study was to determine the reference
values for diaphragmatic motion as recorded by M-mode ultrasonography.
Two hundred ten healthy adult subjects (150 men, 60 women) were investigated. Both
sides of the posterior diaphragm were identified, and M-mode was used to display the
movement of the anatomical structures. Examinations were performed during quiet breathing,
voluntary sniffing, and deep breathing. Diaphragmatic excursions were measured from
the M-mode sonographic images. In addition, the reproducibility (inter- and intra-observer)
was assessed.
Right and left diaphragmatic motions were successfully assessed during quiet breathing
in all subjects. During voluntary sniffing, the measurement was always possible on
the right side, and in 208 of 210 volunteers, on the left side. During deep breathing,
an obscuration of the diaphragm by the descending lung was noted in subjects with
marked diaphragmatic excursion. Consequently, right diaphragmatic excursion could
be measured in 195 of 210 subjects, and left diaphragmatic excursion in only 45 subjects.
Finally, normal values of both diaphragmatic excursions were determined. Since the
excursions were larger in men than in women, the gender should be taken into account.
The lower limit values were close to 0.9 cm for women and 1 cm for men during quiet
breathing, 1.6 cm for women and 1.8 cm for men during voluntary sniffing, and 3.7
cm for women and 4.7 cm for men during deep breathing.
We demonstrated that M-mode ultrasonography is a reproducible method for assessing
hemidiaphragmatic movement.