A 155 lb., 60-year-old man had a chronic productive cough, exertional dyspnea, mild cyanosis, and marked slowing of forced expiration. His pulmonary function and laboratory tests follow:
| Frequency | 15 breaths/min |
| Alveolar ventilation | 4.1 L/min |
| Vital capacity (VC) | 2.2 L |
| Functional residual capacity (FRC) | 4.0 L |
| Total lung capacity (TLC) | 5.2 L |
| Maximum inspiratory flow rate | 252 L/min |
| Maximum expiratory flow rate | 21 L/min |
| PaO2 | 63 mm Hg |
| PaCO2 | 38 mm Hg |
Pulmonary function tests after bronchodilator therapy:
| Frequency | 15 breaths/min |
| Alveolar ventilation | 4.25 L/min |
| VC | 2.4 L |
| FRC | 4.0 L |
| TLC | 5.2 L |
| Maximum inspiratory flow rate | 252 L/min |
| Maximum expiratory flow rate | 24 L/min |
| PaO2 | 63 mm Hg |
| PaCO2 | 37 mm Hg |
Q1: What is the disorder of this man?
Q2: Is this mainly a restrictive or an obstructive disorder? Explain.
Q3: Why is the bronchodilator therapy ineffective for this patient?
Q4: What causes the hypoxemia?
Q5: Calculate the residual volume (RV) for this person before and after the bronchodilator therapy. RV = TLC – VC.
Q6: What is the cause of this altered RV?
Q7: Calculate the tidal volume (TV) for this person before and after the bronchodilator therapy. TV = AV/f + patient body weight. Hint: TV is calculated in mL, so you will need to convert L to mL before completing the equation.
Q8: Is each TV normal or altered?
Q9: Calculate the minute ventilation (MV) for this person before and after the bronchodilator therapy. MV = TV × f
Q10: Is each MV normal or altered?
