Author Question: Which of the following statements are true about low-flow O2 delivery systems? 1. The greater the ... (Read 159 times)

ericka1 · **on:** Jul 16, 2018

Which of the following statements are true about low-flow O2 delivery systems?

1. The greater the patient's inspiratory flow, the greater is the FiO2.
2. All low-flow devices provide variable O2 concentrations.
3. The O2 provided by a low-flow device is diluted with air.
4. The patient's flow usually exceeds that from a low-flow device.
a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

Question 2

Which of the following are true about absorption atelectasis?

1. It can occur only when breathing supplemental O2.
2. Its risk is increased in patients breathing at low tidal volumes (VT values).
3. Its risk is decreased through the natural sigh mechanism.
4. It results in an increase in the physiologic shunt fraction.
a. 1 and 3 only
b. 1, 2, and 3 only
c. 3 and 4 only
d. 2, 3, and 4 only

aprice35067 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: D
In this case, the more the patient breathes, the more air dilutes the delivered O2, and the lower is the FiO2. Hence, there is an inverse or opposite relationship between FiO2 and inspiratory flow with such O2 devices.

Answer to Question 2

ANS: D
The risk of absorption atelectasis is greatest in patients breathing at low tidal volumes as a result of sedation, surgical pain, or CNS dysfunction. In these cases, poorly ventilated alveoli may be-come unstable when they lose O2 faster than it can be replaced. The result is a more gradual shrinking of the alveoli that may lead to complete collapse, even when the patient is not breathing supplemental O2. For an alert patient this is not a great risk, because the natural sigh mechanism periodically hyperinflates the lung.