The chest radiograph of a patient just placed on HFOV shows the diaphragm at the level of the seventh rib. Which of the following parameters should be adjusted?

a. mPaw
b. Power
c. Bias flow
d. Amplitude

ANS: A
The mPaw directly affects the PaO2 by changing the lung volume. The position of the diaphragm on the chest radiograph correlates with lung expansion. Adequate lung expansion in an adult shows the ninth posterior rib above the level of the diaphragm in the midclavicular line. With this patient, the diaphragm is only at the seventh rib. Therefore, the mPaw needs to be increased to improve lung expansion.