Dementia and snoring

A 65-year-old man was admitted to hospital in March, 1995, with confusion and breathlessness. His family reported his confusion, drowsiness, and slurred speech had come on during the preceding year. At night he would often become agitated and have hallucinations. In the previous month he had been admitted to hospital twice with similar symptoms. A diagnosis of dementia was made when a computed tomogram of his brain showed mild cerebral atrophy. He was known to have Chronic Obstructive Pulmonary Disease (COPD) and had smoked for most of his life. No lung-function tests were done. During this admission he was noted to be cyanosed and had pitting oedema in both legs to the mid calf. He was overweight at 98 kg. His chest radiograph was unremarkable. Arterial blood gases (on room air) were: pH 7·27; PCO2 11·6 KPa; PO2 3·8 KPa; bicarbonate 38 mmol/L. Diagnosis of acute or chronic respiratory failure secondary to an exacerbation of his COPD was made. He was treated with oxygen, corticosteroids, nebulised bronchodilators, antibiotics, and intravenous doxopram. He gradually improved over the next few days.