Gas exchange — Flashcards

Flashcard 171: The Po2 in dry inspired air is normally approximately _____ mmHg

Answer: 160

Flashcard 172: The lung diffusing capacity, DL, is _____ proportional to the diffusion coefficient of the gas

Answer: directly

Flashcard 173: Carboxyhemoglobin heme groups not bound by CO have a(n) _____ affinity for O2

Answer: increased

Flashcard 174: DLCO may be used to estimate the extent to which _____ passes from the air sacs of lungs into blood

Answer: oxygen

Flashcard 175: Normally 1g of hemoglobin can bind _____ mL of O2

Answer: 1.34

Flashcard 176: CO2 exhibits _____-limited gas exchange

Answer: perfusion

Flashcard 177: Is the A - a gradient normal, increased, or decreased, in response to diffusion defects (e.g. fibrosis, pulmonary edema)? _____

Answer: Increased

Flashcard 178: In emphysema, the DLCO is usually _____

Answer: decreased

Flashcard 179: What equation is used to determine the physiologic dead space ($V_D$)?

Answer: Bohr equation

Extra: $V_D = V_T \times \frac{P_aCO_2 - P_E CO_2}{P_aCO_2}$ **Mnemonic**: **Ta**co **Pa**co **Pe**co - **T**: Tidal volume ($V_T$) - **a**: arterial $CO_2$ ($P_aCO_2$) - **e**: expired $CO_2$ ($P_E CO_2$)

Flashcard 180: In the steady state, the respiratory quotient, R, is normally equal to _____

Answer: 0.8