As the barometric pressure increases, there is an increase in the density of the gas being breathed. The increase in gas density in turn causes a(n):

a. Decrease in work of breathing c. Increase in work of breathing
b. Increase in FIO2 d. Decrease in FIO2

ANS: C
The increase in gas density results in increased work of breathing, which is not noticeable and can easily be accommodated in healthy subjects. In patients with reduced lung reserves, however, this increased work can present problems and necessitate ventilatory support.