Respiratory - from West's 8th ed Chapter 6 - Gas Transport by the Blood Flashcards
1. The presence of hemoglobin in normal arterial blood increases its oxygen concentration approximately how many times? A. 10 B. 30 C. 50 D. 70 E. 90
D.
Arterial PO2 is 100mmHg, which makes for an oxygen concentration of 100 x 0.003 mL/dL.
Arterial blood contains 15g/dL Hb. Each gram of Hb can combine with 1.39mL oxygen.
2. An increase in which of the following increases the O2 affinity of hemoglobin? A. Temperature. B. PCO2. C. H+ concentration. D. 2,3-DPG. E. Carbon monoxide added to the blood.
E. Adding CO will shift the O2 dissociation curve slightly to the left.
- A patient with carbon monoxide poisoning is treated with hyperbaric oxygen that increases the arterial Po2 to 2,000 mm Hg. The amount of oxygen dissolved in the arterial blood (in ml/100ml) is:
A. 2 B. 3 C. 4 D. 5 E. 6
E
- A patient with severe anemia has normal lungs. You would expect:
A. Low arterial PO2. B. Low arterial O2 saturation. C. Normal arterial O2 concentration. D. Low oxygen concentration of mixed venous blood. E. Normal tissue PO2.
D
- In carbon monoxide poisoning, you would expect:
A. Reduced arterial PO2.
B. Normal oxygen concentration of arterial blood.
C. Reduced oxygen concentration of mixed venous blood.
D. O2 dissociation curve is shifted to the right.
E. Carbon monoxide has a distinct odor.
C. Carbon monoxide has no odor, which is one reason why it is so dangerous.
- The laboratory reports the following arterial blood gas values in a patient with severe lung disease who is breathing air: PO2 60 mm Hg, PCO2 110 mm Hg, pH 7.20. You conclude:
A. Patient has a normal PO2.
B. Patient has a normal PCO2.
C. There is a respiratory alkalosis.
D. There is a partially compensated respiratory alkalosis.
E. The values for PO2 and PCO2 are internally inconsistent.
E. Using the alveolar gas equation, the alveolar PO2 is about 149-110, that is, 39 (for an R value of 1), and even less for an R value less than 1. This is less than the stated arterial PO2, which is not possible.
- Most of the carbon dioxide transported in the blood is in the form of:
A. Dissolved. B. Bicarbonate. C. Attached to hemoglobin. D. Carbamino compounds. E. Carbonic acid.
B
- A patient with chronic lung disease has arterial PO2 and PCO2 values of 50 and 60 mm Hg, respectively, and a pH of 7.35. How is his acid-base status best described?
A. Normal.
B. Partially compensated respiratory alkalosis.
C. Partially compensated respiratory acidosis.
D. Metabolic acidosis.
E. Metabolic alkalosis.
C
- The PO2 (in mm Hg) inside skeletal muscle cells during exercise is closest to:
A. 3 B. 10 C. 20 D. 30 E. 40
A
- A patient with chronic pulmonary disease undergoes emergency surgery. Postoperatively the arterial PO2, PCO2, and pH are 50 mm Hg, 50 mm Hg, and 7.20, respectively. How would the acid-base status be best described?
A. Mixed respiratory and metabolic acidosis.
B. Uncompensated respiratory acidosis.
C. Fully compensated respiratory acidosis.
D. Uncompensated metabolic acidosis.
E. Fully compensated metabolic acidosis.
A
- The laboratory provides the following report on arterial blood from a patient: PCO2 32 mm Hg, pH 7.25, HCO3- concentration 25 mmol/L. You conclude that there is:
A. Respiratory alkalosis with metabolic compensation.
B. Acute respiratory acidosis.
C. Metabolic acidosis with respiratory compensation.
D. Metabolic alkalosis with respiratory compensation.
E. A laboratory error.
E
- A patient with shortness of breath is breathing air at sea level, and an arterial blood sample shows PO2 90 mm Hg, PCO2 32 mm Hg, pH 7.30. Assuming that the respiratory exchange ratio is 0.8, these data indicate:
A. Primary respiratory alkalosis with metabolic compensation.
B. Normal alveolar-arterial PO2 difference.
C. Arterial O2 saturation less than 70%.
D. The sample was mistakenly taken from a vein.
E. Partially compensated metabolic acidosis.
E
