The Effects of Employing Pillows for Postural Changes on Ventilation: An Investigation Using an Ultrasonic Imaging Device

Abstract

[Purpose] We investigated the effects of compression on the posterior surface of the thorax caused by a pillow used for postural changes on the respiratory function. [Subjects] The subjects were 22 healthy males with no history of ailments of the respiratory and circulatory organs. [Methods] With the subjects placed in the supine position, a half-lateral position with a pillow supporting the posterior surface of the thorax (pillow-supported position (1)), and a half-lateral position with pillows supporting the shoulder girdle and the pelvic band (pillow- supported position (2)), the ventilatory volume per breath (hereinafter TV) and expiratory reserve volume (hereinafter ERV) were measured based on the respiratory function, and at the same time, the distanced moved by the diaphragm was measured using an ultrasonic imaging device. [Results] Significantly lower values for TV were observed in the pillow-supported position (1) in comparison to the other postures. Significantly higher values for ERV were observed in the pillow-supported position (1) in comparison to the other postures. Significantly lower values for the distance moved by the diaphragm were observed in the pillow-supported position (1) in comparison to the other postures. [Conclusion] Ventilation decreased in pillow-supported position (1). We therefore consider that the movement of the diaphragm was reduced due to an expanded state caused by increase in residual air in the lungs.