Anatomical subdivisions of the volume of respiratory dead space and effect of position of the jaw

Abstract

The mean volume of the extrathoracic respiratory tract in six cadavers was found to be 72 ml (BTPS), (S.D. ±32). Expressed as a fraction of body weight in pounds this amounted to 0.55. The intrathoracic anatomical dead space was measured in three intubated subjects. The mean value was 66 ml (BPTS), (S.D. ±29) or 0.43 times the body weight in pounds. The influence of the position of the jaw on the dead space was studied in the six cadavers and three conscious subjects. Depression of the jaw with flexion of the neck produced a mean decrease in the dead space of 31.4 ml while a protrusion of the jaw with extension of the neck increased the dead space by 39.7 ml. Submitted on July 28, 1958