A patient in the subacute care unit is receiving NIV with a PTV ...

[roselinechinyere27m]

A patient in the subacute care unit is receiving NIV with a PTV system, with an IPAP of 10 cm H2O and an EPAP of 3 cm H2O.
 
  The patient's latest arterial blood gas values reveal an increase in the PaCO2. The most appropriate action to take is which of the following?
  a. Increase the IPAP.
  b. Decrease the IPAP.
  c. Increase the EPAP and IPAP.
  d. Intubate and mechanically ventilate.

Question 2

If oxygen is bled into each of the following portable PTVs at the same rate, which of the follow-ing combinations will provide the highest oxygen concentration?
 
  a. Leak port at mask, oxygen bleed at mask, IPAP 8 cm H2O, EPAP 16 cm H2O
  b. Leak port at mask, oxygen bleed at ma-chine outlet, IPAP 6 cm H2O, EPAP 18 cm H2O
  c. Leak port in circuit, oxygen bleed at mask, IPAP 5 cm H2O, EPAP 10 cm H2O
  d. Leak port in circuit, oxygen bleed in cir-cuit, IPAP 5 cm H2O, EPAP 15 cm H2O

[Joy Chen]

Answer to Question 1

ANS: C
The EPAP of 3 cm H2O is not providing enough continuous flow of gas through the system to minimize the rebreathing of CO2. Increasing both the EPAP and IPAP will provide enough flow to wash out the CO2 and keep the pressure support DIF consistent.

Answer to Question 2

ANS: C
The highest oxygen concentration will occur when the IPAP and EPAP DIFs are lower. The lowest DIF in this question is an IPAP of 5 cm H2O and an EPAP of 10 cm H2O. Also, if the leak port is in the circuit, higher oxygen concentrations are obtained when the oxygen is bled into the patient's mask.