The Effect of Upper Chest Wall Restriction on Diaphragmatic Function

Abstract

Abstract.[Purpose] The purpose of the present study was to determine whether transient upper chest wall restriction would enhance diaphragmatic contribution to tidal volume in healthy subjects. [Methods] Changes of diaphragm thickness (ΔTdi) were studied by ultrasound in 24 healthy male subjects in the supine position. Tidal volume (Vt) and respiratory rate were measured by spirometer. ΔTdi with each breath was expressed as percentage of the thickness at the end of expiration (ΔTdi%) and the ratio of ΔTdi% to tidal volume was calculated (ΔTdi%/Vt). The upper rib cage was compressed with a sphygmomanometer cuff to restrict its motion. All parameters were measured in three conditions: during rib cage compression, prior to the compression, and subsequent to the compression.[Results] When upper rib cage compression was applied, ΔTdi% significantly increased, whereas it returned to baseline levels upon release of the compression. ΔTdi%/Vt tended to increase, however there was no significant difference. Subjects were divided into those who showed an increase in ΔTdi%/Vt (group 1: n=16) and those who showed a decrease (group 2: n=8). Prior to the compression, ΔTdi% and ΔTdi%/Vt of group 1 were higher than those of group 2.[Conclusion] These results suggest that in healthy male subjects transient upper rib cage ristriction may enhance diaphragmatic contribution to tidal volume, particularly in those subjects with low initial diaphragm recruitment.

Contractile capability of the diaphragm assessed by ultrasonography predicts nocturnal oxygen saturation in COPD

“…We measured the thickness of the diaphragm (Tdi) in the zone of apposition using B‐mode ultrasound imaging. In the supine position, an 18‐5 MHz linear transducer was placed on the chest wall in the eighth or ninth right intercostal space between the antero‐axillary and mid‐axillary line . Real‐time motion of the diaphragm, imaged via the non‐echogenic muscular layer outlined echogenically by the membranes of the peritoneum and diaphragmatic pleura, was recorded as a movie.…”

“…The mean values of Tdi at TLC (Tdi TLC ) and RV (Tdi RV ) were calculated. The change of Tdi (ΔTdi) was calculated as the absolute value of the difference between Tdi TLC and Tdi RV , and the change ratio of Tdi (%ΔTdi) was expressed as a percentage of Tdi RV …”

“…In the supine position, an 18-5 MHz linear transducer was placed on the chest wall in the eighth or ninth right intercostal space between the antero-axillary and mid-axillary line. [12][13][14][15][16][17] Real-time motion of the diaphragm, imaged via the non-echogenic muscular layer outlined echogenically by the membranes of the peritoneum and diaphragmatic pleura, was recorded as a movie. The participants performed at least three breaths and three images were captured at the end of the maximal inspiration (total lung capacity, TLC) and the end of the maximal expiration (residual volume, RV).…”

“…This research showed that inspiratory muscle strength was useful to predict NSaO 2 and desaturation, but measurement of Pdi, a specific indicator of diaphragmatic function, was invasive. However, ultrasound imaging, a non‐invasive method, has been used widely for imaging of the diaphragm . We hypothesized that ultrasound imaging could be substituted for the invasive methods to assess diaphragm function indicators such as Pdi.…”

“…However, ultrasound imaging, a non-invasive method, has been used widely for imaging of the diaphragm. [12][13][14][15][16][17] We hypothesized that ultrasound imaging could be substituted for the invasive methods to assess diaphragm function indicators such as Pdi.…”