A 64 year old woman with headache and breathlessness

The ensuing alveolar hypoventilation leads to hypercapnic respiratory failure and the associated symptoms of morning headaches, daytime sleepiness, and dyspnoea. Because this comprises the majority of normal sleep, a more serious and prolonged rise in carbon dioxide tension occurs. Overnight pulse oximetry and transcutaneous monitoring of carbon dioxide followed by analysis of early morning arterial blood gases will confirm the presence of alveolar hypoventilation by showing a rise in carbon dioxide saturation and fall in oxygen saturation. 6 Oximetry may identify evidence of upper airway obstruction suggestive of coexistent obstructive sleep apnoea-hypopnoea syndrome. Data from 244 patients with respiratory failure as a result of kyphoscoliosis show a clear survival benefit with NIV over long term oxygen therapy. 9 NIV has also been shown to improve quality of life in kyphoscoliosis. 7 However, no data from randomised controlled trials are available to date.