ALVEOLAR HYPOVENTILATION WITH NORMAL LUNGS: THE SYNDROME OF PRIMARY OR CENTRAL ALVEOLAR HYPOVENTILATION *

Abstract

Summary This paper describes the cases of primary or central alveolar hypoventilation syndrome that have been reported, as well as three previously unreported cases seen in our hospital. Although the presenting symptoms of the patients were quite different, physiologically they were quite similar. Significant neurological disease was noted to coexist in a majority of the patients. This fact, plus the physiological observations of essentially normal lung and chest bellows function, and a decreased to absent response to inhaled CO 2 , suggest that this disorder is the result of a disturbance in the medullary respiratory center. The mortality has been 20 per cent. Interesting neuropathological abnormalities have been noted in the area of the respiratory center and elsewhere, consisting of an increased number of capillaries. Whether this is a primary or secondary change is not clear. A variety of therapies has been used in an attempt to augment alveolar ventilation. These include pharmocological agents, hypnosis, implantation of pacemaker electrodes into the diaphragm and later the phrenic nerve, and the use of simulated breath sounds. The details and results of these modalities of therapy are described.