Author Question: A female patient (59-kg IBW) with no history of pulmonary disease is being invasively ventilated ... (Read 134 times)

ts19998 · **on:** Jul 16, 2018

A female patient (59-kg IBW) with no history of pulmonary disease is being invasively ventilated with VC-CMV, f = 12/min, VT = 470 mL, PEEP = 5 cm H2O, FIO2 = 0.5.

ABG results with these settings are: pH 7.31, PaCO2 54 mm Hg, PaO2 92 mm Hg, SaO2 90, HCO3 24 mEq/L. The most appropriate action for the respiratory therapist to take is which of the following?
a. Increase f to 16/min.
b. Increase VT to 635 mL.
c. Decrease VT to 400 mL.
d. Decrease PEEP to 3 cm H2O.

Question 2

A male patient (76-kg IBW) with no history of pulmonary disease is brought to the emergency department for treatment of a drug overdose. He is intubated and placed on mechanical ventila-tion with VC-CMV, f = 12/min, VT = 450 mL.

The resulting arterial blood gas values are: pH 7.32, PaCO2 53 mm Hg, and HCO3 25 mEq/L. The most appropriate action to correct the acid-base disturbance is which of the following?
a. Increase VT to 595 mL.
b. Increase VT to 760 mL.
c. Increase frequency to 16/min.
d. Decrease frequency to 10/min.

meow1234 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: A
The target VT for an individual without pulmonary disease is 5-8 mL/kg IBW. This patient's VT range is 295-472 mL, meaning that the upper limit of this range has been reached. The f should be changed to increase this patient's minute ventilation.

Answer to Question 2

ANS: A
Desired VT Known PaCO2 Known VT / Desired PaCO2
The desired target for VT for this patient is 5-8 mL/kg IBW. Because the set VT of 450 mL is at 5.9 mL/kg, there is room to increase the VT. After calculating the desired VT using the formula, the new volume is at 7.8 mL/kg. A VT of 760 mL would be at 10 mL/kg IBW.