1. a, b are correct

Incorrect:

c) patient may hyperventilate by breathing deeper than normal, or may even hyperventilate with both normal rate and depth if the level of CO₂ production falls.

d) patient could have metabolic acidosis

e) patient is not in a steady state for gas exchange since there is acute hyperventilation

2. a, b, c and e are correct

Incorrect:

d) In patients who may have lung disease, there are no useful bedside parameters for determining whether PaCO₂ is high or low.

3. b, c and e are correct.

Incorrect:

a) anemia reduces oxygen content, not PaO₂

d) carbon monoxide reduces SaO₂ and CaO₂, not PaO₂

4. a and d are correct

Incorrect:

b, c, and e; you need at least two of the three variables in the Henderson-Hasselbalch equation to assess the acid-base state of a patient's blood.

5. a, b, c and d are correct

incorrect:

e) In theory, the plasma HCO₃^- calculated from blood gases should be @ 2-4 mEq/L less than the serum CO₂ measured on a venous sample, since venous bicarbonate is higher than arterial and also because serum CO₂ measurement includes the quantity contributed by dissolved CO₂.

6. a, c, d, e are correct.

Incorrect:

b) Other determinants are those factors that affect the position of the oxygen-dissociation curve, e.g., temperature, pH, PaCO₂ and 2,3 DPG

7. c, d and e are correct

Incorrect:

a) each gram of hemoglobin can combine with 1.34 ml of O₂

b) Normal CaO₂ is between 16 and 22 ml O₂ /dl

8. a, c and e are correct

Incorrect:

b) arterial PO₂ and pH are not directly related by any equation

d) arterial PO₂ is related to SaO₂ by the O₂ dissociation curve, which has a sigmoid configuration

9. b and d are correct

Incorrect:

a) "hyperventilation" and "hypoventilation" should only be used clinically as they relate to the PaCO₂

c) people with normal lungs can increase arterial PO₂ above 100 mm Hg with hyperventilation

e) a patient can have profound acid-base imbalance yet normal pH from opposing acid-base disorders (e.g., combined metabolic acidosis and metabolic alkalosis)

10. a, b, e are correct

Incorrect:

c) The pulse oximeter is not equal in accuracy to the co-oximeter, since the latter employs four wavelengths of light to differentiate hemoglobin moieties; the pulse oximeter uses only two wavelengths, and reads carboxyhemoglobin and oxyhemoglobin together.

d) The end-tidal PCO₂ is usually equal to or lower than the PaCO₂. In lung diseases with V-Q imbalance, excess dead space contributes air with low or zero PCO₂ to the end-tidal sample, making end-tidal PCO₂ lower than PaCO₂.