Author Question: Which of the following are true statements regarding the volume of tissue nitrogen excreted dur-ing ... (Read 68 times)

tiara099 · **on:** Jul 16, 2018

Which of the following are true statements regarding the volume of tissue nitrogen excreted dur-ing the N2 washout test for measuring functional residual capacity (FRC)?

1. It is not a factor.
2. It varies with the length of the test.
3. It varies with the weight of the patient.
4. It cannot be correct.
a. 1 only
b. 2 and 3 only
c. 2, 3, and 4 only
d. 4 only

Question 2

To what should all spirometric values obtained under ambient conditions be converted?

a. Ambient temperature and pressure, satu-rated (ATPS)
b. Standard temperature and pressure, dry (STPD)
c. Body temperature, ambient pressure, sat-urated (BTPS)
d. Ambient temperature and pressure, dry (ATPD)

ryhom · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: B
The volume of tissue nitrogen excreted (Vtis in milliliters) is directly related to the duration (t in minutes) of the test and weight (W in kilograms) of the patient. A correction for this extra nitro-gen should be made according to the following formula:
Vtis (ml) = (0.1209 0.0665) (W/70). Vtis (ml) is subtracted from the BTPS-corrected lung volume. The residual volume is the difference between the expiratory reserve volume and the FRC.

Answer to Question 2

ANS: C
All lung volumes and capacities must be reported under BTPS conditions.