Author Question: A patient being ventilated with APRV has the following settings: Phigh = 24 cm H2O; Thigh = 5 sec; ... (Read 38 times)

dalyningkenk · **on:** Jul 16, 2018

A patient being ventilated with APRV has the following settings: Phigh = 24 cm H2O; Thigh = 5 sec; Plow = 4 cm H2O; Tlow = 1 second, FIO2 = 0.3.

The patient's spontaneous respiratory rate is 10 breaths/min. The current arterial blood gas values are: PaO2 = 91 mm Hg; PaCO2 = 62 mm Hg. What should the respiratory therapist recommend for this patient?
a. Increase the Plow to 5.5 cm H2O.
b. Decrease the Tlow to 0.5 sec.
c. Increase the Phigh to 40 cm H2O.
d. Decrease the Plow to 0 cm H2O.

Question 2

Which variable in APRV is responsible for the removal of CO2 from the body?

a. Tlow
b. Thigh
c. Plow
d. Phigh

bd5255 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: D
To decrease the PaCO2, the Phigh/Plow gradient needs to be increased without increasing the Phigh above 35 cm H2O. Decreasing the Plow to 0 cm H2O is one way to increase that gradient. Increas-ing the Plow would decrease the gradient and therefore the VT. Although raising the Phigh would increase the pressure gradient and therefore the VT, pressures above 35 cm H2O increase the risk of overdistention injury.

Answer to Question 2

ANS: A
During the release time, or Tlow, the patient exhales a volume of gas; this allows ventilation and the removal of CO2 from the body.