Objective: To summarize the experience in diagnosis and treatment of pulmonary hypertension caused by sleep hypoventilation.
Methods: The clinical data of 4 patients in a family with pulmonary hypertension caused by sleep hypoventilation, full brothers and sisters, 2 (Cases 1 and 2) being treated presently and 2 (Cases 3 and 4) being deceased and traced by family medical history, were retrospectively analyzed.
Results: Three of the 4 cases (cases 1, 3, and 4) were misdiagnosed as with cor pulmonale combined with pulmonary hypertension, and one case (case 2) was misdiagnosed as with primary pulmonary hypertension. Polysomnography (PSG) revealed alveolar hypoventilation-induced long period of oxygen desaturation at sleep in Cases 1 and 2, thus confirming the diagnosis. Pulmonary function test showed that the percentage of maximum inspiratory pressure (PImax) in predicted value (51.5% and 20.9%) and the maximum expiratory pressure (PEmax) in predicted value (51.3% and 29.6%) decreased, the percentage of mouth occlusion pressure (P0.1) in predicted value (141% and 133%) compensatively increased, and the respiratory muscle strength decreased in Cases 1 and 2, which suggested that there was neuromuscular disorder in these patients. Treated by noninvasive ventilation the symptoms of these 2 patients were improved and they were discharge at last. Subsequently, they were treated by long-term night noninvasive ventilation at home, and returned to normal work and life. During the follow-up for 22 and 12 months respectively after discharge, PSG showed that the alveolar hypoventilation-induced long period oxygen desaturation at sleep had been greatly improved, and echocardiogram showed that the pulmonary pressure was greatly decreased.
Conclusion: For the patients with unexplained pulmonary hypertension, PSG monitoring and pulmonary function tests such as PImax, PEmax, and P0.1 help determine the etiology, and long-term night noninvasive ventilation at home can improve the outcome of sleep hypoventilation-induced pulmonary hypertension.