Compared with a square wave flow pattern, a decelerating flow waveform has which of the fol-lowing potential benefits?

1. Reduced peak pressure
2. Improved cardiac output
3. Less inspiratory work
4. Decreased volume of dead space-to-tidal volume ratio (VD/VT)
a. 1 and 3 only
b. 1, 3, and 4 only
c. 2 and 4 only
d. 2, 3, and 4 only

ANS: B
Compared with a square flow waveform, decreasing flow has been shown to reduce peak pres-sure, inspiratory work, VD/VT, and P(A−a)O2 without affecting hemodynamic values.