| Question | Answer |
| A patient has a whole-body oxygen consumption of 320 ml/min and a measured CaO2 - Cv O2 of 8 ml/dl. What is the cardiac output? | B) 4.0 L/min |
| When Hb saturation with oxygen is high, less carbon dioxide is carried in the blood. What is this relationship called? | D) Haldane effect |
| What is the affect of an elevated intracellular 2,3-DPG concentration? | C) Increases the availability of oxygen to the tissues. |
| The time available for diffusion in the lung is mainly a function of which of the following? | D) Rate of pulmonary blood flow |
| A 70-kg male patient has a VCO2 of 200 ml/min and a VA of 9 L/min. From this information, what can you infer? | C) The patient will have a lower than normal PACO2. |
| The expected PaO2 for an 80-year-old man who is otherwise in good health and breathing room air is about what level? | B) 75 mm Hg |
| What is the approximate normal CaO2 - CvO2 in a healthy adult at rest? | A) 5 ml/dl |
| What is the most important component in the oxygen transport system? | C) Hb |
| When a Hb molecule accumulates excessive amounts of HCO3-, it is expelled from the cell in exchange for Cl-. What is this called? | C) Hamburger phenomenon |
| Carbon dioxide is most commonly elevated due to significant pulmonary disease that results in small tidal volumes. | B) True |
| What does V/Q mismatch have the biggest impact on? | C) Oxygenation |
| Which of the following best represents the partial pressures of all gases in the normally ventilated and perfused alveolus when breathing room air at sea level? | B) PO2 = 100 mm Hg; PCO2 = 40 mm Hg; PN2 = 573 mm Hg; PH2O = 47 mm Hg |
| Under normal physiologic circumstances, how many milliliters of oxygen are capable of combining with 1 g of Hb? | D) 1.340 ml |
| In which of the following conditions will erythrocyte concentration of 2,3-DPG be decreased? | B) Banked blood |
| Which of the following conditions must exist for gas to move between the alveolus and pulmonary capillary? | B) Difference in partial pressures (pressure gradient) |
| In which of the following forms is carbon dioxide transported by the blood? | D) I, II, and III I. Chemically combined with proteins II. Ionized as bicarbonate (HCO3-) III. Simple physical solution |
| A patient has a P50 value of 29 mm Hg. What does this indicate? | A) Decreased affinity of Hb for oxygen. |
| The oxidation of the Hb molecule’s iron ions to the ferric state (Fe3+) results in which of the following? | C) II and III II. Formation of methemoglobin (metHb). III. Inability of metHb to bind with oxygen. |
| Regarding pulmonary blood flow in the upright lung, which of the following statements is true? | B) The bases receive about 20 times more blood flow than the apexes. |
| The lowest PO2 would normally be found in what location? | C) Cells |
| Which of the following “layers” must be traversed by gases moving across the alveolar-capillary membrane? | A) I, II, and III I. Alveolar epithelial membrane II. Capillary endothelial membrane III. Interstitial space IV. Transbronchial radial tethering mechanisms |
| What is the minimum amount of time that blood must take for pulmonary capillary transit for equilibration of oxygen to occur across the alveolar-capillary membrane? | B) 0.25 second |
| What is the most common cause of hypoxemia? | D) V/Q mismatch |
| Which of the following are potential causes of hypoxia? | D) I, II, and III I. Decrease in arterial PO2. II. Decrease in available Hb. III. Decrease in cardiac output. |
| An area of the lung has no ventilation but is normally perfused by the pulmonary circulation. Which of the following statements are correct? | D) I, II, and III I. Blood exiting the pulmonary capillary will have a PO2 = 40 and a PCO2 = 46. II. The area represents an alveolar shunt. III. The V/Q is 0. |
| In a person breathing room air (and with all else being normal), if the alveolar PCO2 rises from 40 to 70 mm Hg, what would you expect? | A) PAO2 to fall by about 30 mm Hg |
| Which of the following equations best describes oxygen delivery to the tissues? | B) arterial oxygen content x cardiac output |
| Which of the following values corresponds most closely to the normal PO2 and PCO2 in the mixed venous blood returning to the lungs from the right side of the heart? | A) PO2 = 40 mm Hg; PCO2 = 46 mm Hg |
| Which of the following does NOT increase the affinity of Hb for oxygen? | D) Increased temperature |
| On what does the movement of gases between the lungs and the body tissues mainly depend? | B) Gaseous diffusion |
| An abnormal metabolic state in which the tissues are unable to utilize the oxygen made available to them best describes which of the following? | B) Dysoxia |
| What is the highest PAO2 one could expect to observe in an individual breathing room air at sea level? | B) 110 to 120 mm Hg |
| As the amount of oxygen that dissolves in the plasma increases, what is it directly proportional to? | A) Its partial pressure |
| Which of the following are true regarding fetal hemoglobin (HbF)? | C) It delivers more oxygen to tissues at low PaO2 than normal Hb. |
| According to the Bohr effect, when the pH drops (blood becomes more acidic), what happens? | A) I and II I. The affinity of Hb for oxygen decreases. II. The Hb saturation for a given PO2 falls. |
| Given the following blood parameters, compute the total oxygen content (dissolved + HbO2) of the blood in ml/dl: Hb = 16; PO2 = 625 Hg; SO2 = 100%. | D) 23.3 ml/dl |
| Which of the following gases would diffuse fastest across the alveolar-capillary membrane? | B) Carbon dioxide |
| Why is it necessary to keep the patient’s PaO2 greater than 60 mm Hg? | A) A level of 60 mm Hg marks the beginning of the steep part of O2Hb dissociation curve. |
| Compared to normal levels, a shift in the HbO2 curve to the right has which of the following effects? | B) I and II I. The affinity of Hb for oxygen decreases. II. The Hb saturation for a given PO2 falls. |
| At body temperature, how much oxygen will physically dissolve in plasma at a PO2 of 40 mm Hg? | A) 0.12 ml/dl |
| The affinity of Hb for carbon monoxide (CO) is approximately how many times greater than its affinity for oxygen? | D) 200 or greater |
| The highest PCO2 levels are found in what location? | C) Cells |
| Given the following blood parameters, compute the total oxygen content (dissolved + HbO2) of the blood in ml/dl: Hb = 18; PO2 = 40 mm Hg; SO2 = 73%. | B) 17.7 ml/dl |
| According to the Fick principle, if oxygen consumption remains constant, an increase in cardiac output will manifest itself as which of the following? | A) Decrease in the CaO2 - CvO2 |
| Even in healthy young subjects, regional differences in pulmonary ventilation and blood flow result in the PaO2 being lower than the PAO2. Why is this so? | C) Most blood flows through the bases of the lung. |
| Under what conditions will the alveolar PACO2 rise above normal? | C) If VA decreases relative to carbon dioxide production. |
| What role does the Bohr effect play in oxygen transport? | C) Enhances oxygen delivery to tissues and oxygen pickup at lungs. |
| Which of the following would you expect to find with “oxygen debt”? | B) I and II I. Accentuated in diseases such as sepsis. II. Oxygen demand exceeds oxygen delivery. |
| If the total hemoglobin content (Hb + HbO2) of a sample of blood is 20 g/dl and the oxyhemoglobin (HbO2) content is 15 g/dl, what is the HbO2 saturation? | C) 75% |
| What occurs in the bases of the upright lung? | D) The V/Q is lower than the average. |
