Author Question: During which phase of a capnogram does inhalation occur? a. Phase 1 b. Phase 2 c. Phase 3 d. ... (Read 109 times)

JMatthes · **on:** Jul 16, 2018

During which phase of a capnogram does inhalation occur?

a. Phase 1
b. Phase 2
c. Phase 3
d. Phase 4

Question 2

The respiratory therapist has just stopped postural drainage for a 24-year-old patient with cystic fibrosis because of shortness of breath and slight cyanosis in the head-down position.

The respiratory therapist should recommend which of the following adjustments to therapy?
a. Continue postural drainage and monitor patient with capnography.
b. Use only upright or flat postural drainage positions and draw an arterial blood gas (ABG).
c. Administer oxygen via nasal cannula and monitor with pulse oximetry.
d. Use a transcutaneous partial pressure of oxygen (PtcO2) monitor to assess the ex-tent of hypoxemia.

isabelt_18 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: D
During inhalation the capnogram will have a zero reading because there is no exhalation of car-bon dioxide (CO2). As soon as the exhalation phase begins there is rise of the waveform. In phase 1, the initial gas exhaled is from the conducting airways, which contain low levels of CO2 from inspired air. During phase 2, alveolar gas containing CO2 mixes with gas from the anatomical airways and the CO2 concentration rises. In phase 3, the curve plateaus as alveolar gas is exhaled. In phase 4, the concentration falls to zero because inspiration is occurring.

Answer to Question 2

ANS: C
The presence of slight cyanosis and shortness of breath in the head-down position is indicative of hypoxemia. The respiratory therapist should administer supplemental oxygen via nasal cannula (possibly 1-2 L/min) and monitor the patient with a continuous pulse oximetry. Capnography is not useful in detecting hypoxemia. Using flat postural drainage positions where the head is not lower than the shoulders has not been proven to be effective.