Excessive Polycythemia of High Altitude: Role of Ventilatory Drive and Lung Disease1–3
| Autor: | John V. Weil, Meir H. Kryger, David V. Collins, Robert E. McCullough, Robert F. Grover, Robert Doekel |
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| Rok vydání: | 1978 |
| Předmět: |
Pulmonary and Respiratory Medicine
Spirometry medicine.diagnostic_test business.industry Dead space respiratory system Hypoxia (medical) respiratory tract diseases Hypoxemia Hypoventilation Anesthesia Medicine medicine.symptom business Hypercapnia Tidal volume Respiratory minute volume circulatory and respiratory physiology |
| Zdroj: | American Review of Respiratory Disease. 118:659-666 |
| ISSN: | 0003-0805 |
| DOI: | 10.1164/arrd.1978.118.4.659 |
| Popis: | Persons residing at high altitude who develop excessive polycythemia are more hypoxemic than normal high-altitude residents. We investigated the causes of hypoxemia in 20 patients with excessive polycythemia residing at an altitude of 3,100 m. Lung disease evidenced by abnormal spirometric features and results of a respiratory questionnaire was present in 10 of 20 patients and resulted in increased alveolar-arterial difference for PO2 [(A-a)PO2]. The excessive hypoxemia in the patients with normal lungs was not due to increased (A-a)PO2. We measured ventilatory responses to hypoxia and to hypercapnia to determine whether blunting of these responses was a cause of this excessive hypoxemia. We found, however, that chemical drives to breathe, although blunted, were the same in patients with polycythemia as in high-altitude control subjects. However, an abnormal breathing pattern was observed; the polycythemic patients had a smaller tidal volume and a greater ratio of dead space to tidal volume than did the normal subjects. In addition, the polycythemic patients had increased minute ventilation on breathing 100 percent O2, whereas the normal subjects did not. Thus, hypoxic depression of ventilation may have been present. Our findings suggested that blunted chemical drives are not causative in this disease, and that some other cause of hypoxemia must be present. |
| Databáze: | OpenAIRE |
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