[Assessment of cyclic and phasic oxygen saturation using pulse oximetry in the diagnosis of nocturnal respiratory disorders].

Nocturnal pulse oximetry is frequently used in screening studies when diagnosing nocturnal respiratory disorders. Short-term cyclic desaturations of oxygen can serve to indicate recurring apnoeas, whereas long-lasting phasic reductions of oxygen saturation are predominantly seen in hypoventilation. However, there are no uniform assessment criteria. We developed a computer programme for the differentiated assessment of cyclic and phasic oxygen desaturations. With this programme it is possible to characterise the individual phases in respect of gradient and duration of the decrease in oxygen saturation, of the starting, minimal and final values and the total duration of the desaturation phase. This enables determination of the rate of incidence of various forms of desaturation during nocturnal recording. The results of this differentiated analysis of nocturnal pulse oximetry in patients with sleep apnoea syndrome (n = 6) and with chronic obstructive airways disease with respiratory insufficiency (n = 6) and without respiratory insufficiency (n = 6) are demonstrated as model examples.