Questions to prepare for classes and examination
• Typical forms of disorder of the respiratory system:
— disorders of alveolar ventilation;
— disorders of pulmonary perfusion;
— disorder of ventilation-perfusion matching;
— disorder of diffusive capacity of the alveolar-capillary barrier.
• Static and dynamic parameters of breathing used to characterize ventilation.
• Alveolar hyperand hypoventilation: causes, mechanisms of development, consequences, and typical changes in breathing volumes.
• Disorders of the neurogenic control of breathing. Pathological forms of breathing.
• Types and consequences of perfusion dicorders: pulmonary arterial hyperand hypotension, venous hypertension.
• Types and mechanisms of ventilation-perfusion mismatch.
• Diseases characterized by abnormal diffusive capacity of the alveolarcapillary barrier. Pneumoconiosis.
• Combined disorders of respiratory function. Adults respiratory distress syndrome.
N 106
A 38-year-old patient K. has a history of heavy smoking more than 1.5 packs of cigarettes per day for the last 12 years. He complains of recurrent bronchitis and tracheitis, persistent cough with secretions, and dyspnea during physical exertion. On examination: the patient has asthenic body habitus, the barrel chest; he uses accessory muscles during breathing. X-ray of the chest shows diminished lungs vascular markings, diaphragm depression and the bronchioles' walls thickening.
Arterial blood gases:
PaO2 - 83 mm Hg.
PaCO2 - 49 mm Hg.
Oxygen carrying capacity - 19.0 vol%.
SaO2 - 96.1%.
The results of spirometry (% to normal values): Total lung capacity - 119%. Vital capacity - 80%. Inspiratory reserve volume - 86%. Expiratory reserve volume - 88%. Functional residual volume - 112%. Residual volume - 114%.
Tiffeneau ratio (FEV1/FVC) - 85%.
The patient has signs of a diminished diffusive capacity of the alveolocapillary membrane; his breathing rate is 20 per minute. After injection of bronchodilator drug aminophylline (euphylline) the value of Tiffeneau ratio increases by 7%.