Influence on Ventilation of a Pillow Used for Position Change as Examined by an Ultrasound Diagnostic Imaging Device

Abstract

The influence on respiratory function of the pressure exerted by a pillow placed behind the back for position change was examined. [Subjects] The subjects were 22 normal healthy males with no history of respiratory or cardiovascular disease. [Method] The tidal volume (TV) and expiratory reserve volume (ERV) were calculated from the respiratory function under two conditions: with the pillow placed at the back in side-lying (P1), and with the pillow placed between the scapular arch and the pelvic girdle in side-lying (P2). At the same time, the distance moved by the diaphragm (DD) was measured by an ultrasound diagnostic imaging device. [Results] In P1, a significantly lower value for TV, a significantly higher value for ERV, and a significantly shorter value of DD were shown. [Conclusion] Ventilation was decreased in P1, and the results suggest that the decrease in diaphragm movement resulted from increased residual air in the lungs putting them in an expanded state.