Which of the following may indicate a decrease in systemic vascular blood flow during high-frequency ventilation?

1. High central venous pressure (CVP)
2. Low CVP
3. Decreased mean arterial pressure (MAP)
4. Increased MAP
a. 1 and 3 only
b. 2 and 3 only
c. 1 and 4 only
d. 1, 2, 3, and 4

ANS: B
Increases in CVP or decreases in MAP indicate decreases in systemic blood flow as a result of overdistention of the lung and inappropriately high −Paw, after adequate intravascular volume has been established.