If respiratory acidosis persists after alveolar ventilation of a ...

[geoffrey]

If respiratory acidosis persists after alveolar ventilation of a patient has been increased, which of the following could be the cause?
 
  a. Chronic obstructive pulmonary disease
  b. Pulmonary embolism
  c. Pulmonary edema
  d. Low PEEP levels

Question 2

A male patient (74-kg IBW) is being ventilated with PC-CMV, f = 12/min, PIP = 20 cm H2O, TI = 1.5 seconds; the resulting flow-time scalar is shown below.
 
  The patient's measured VT is 435 mL. ABG results on these settings are: pH 7.32, PaCO2 54 mm Hg, HCO3 25 mEq/L. The most appropriate action to take is which of the following?
 
  a. Increase f to 16/min.
  b. Increase TI to 2.5 sec.
  c. Increase PIP to 27 cm H2O.
  d. Decrease flow rate to 40 L/min.

[blakeserpa]

Answer to Question 1

ANS: B
If pure respiratory acidosis persists even after alveolar ventilation has been increased, the patient may have a problem with increased dead space. One cause of increased dead space is a pulmo-nary embolism or low cardiac output, resulting in low pulmonary perfusion.

Answer to Question 2

ANS: C
The flow-time scalar shows that TI is adequate, because it shows a time of zero flow during in-spiration. Therefore, changing TI would not be appropriate. The measured VT for this patient is at 5.9 mL/kg IBW; therefore, the VT could be increased. In the PC mode, this would be done with by increasing the set PIP using the following formulas:

[geoffrey]

Thank you

[blakeserpa]

Happy to help you