The effect of postural change and upper respiratory tract infection on middle ear pressure.

The effect of a change in posture from sitting erect to lying supine and horizontal on middle ear pressure was investigated in 5 healthy adults and 5 adults with symptoms of an acute upper respiratory tract infection (URTI). The change in posture had no significant effect on middle ear pressure in the healthy subjects (p greater than 0.05). In those with URTI mean middle ear pressure increased from -39.5 daPa (erect) to -16.9 daPa (supine) (p = 0.026, n = 10). In the supine posture the middle ear pressure in subjects with URTI was raised. The cause of the increase in middle ear pressure is discussed in terms that the postural change may alter middle ear physiology such that in the supine posture there is a net production of middle ear gas as opposed to a net reabsorption in the erect posture. This may indicate that an increase in jugular venous pressure causes a net positive production of middle ear gas.