Idiopathic Alveolar Hypoventilation: Clinical Spectrum

Seven patients had varying degrees of impaired pulmonary function but in other respects resembled patients with idiopathic alveolar hypoventilation. These patients were characterized by chronic cor pulmonale; a diminished ventilatory response to inhaled carbon dioxide; carbon dioxide retention disproportionate to the extent of airflow obstruction; and by the ability to voluntarily hyperventilate and return PaO2 and PaCO2 to normal or near normal levels. These studies suggest that the clinical spectrum of idiopathic alveolar hypoventilation, that is, inappropriate or unexplained carbon dioxide retention, can be extended to include some patients with obstructive and restrictive lung disease and that respiratory insensitivity to carbon dioxide is commoner than previously recognized.