[Diurnal basal pulmonary arterial pressure and nocturnal levels of oxygenation in patients with chronic bronchitis].

The relationship between diurnal pulmonary arterial pressure (Ppa) measured in steady state and nocturnal level of oxyhaemoglobin saturation (Sao2) measured continuously was studied in fourteen patients with chronic obstructive lung disease. A right heart catheterization was carried out in the morning in each patient. The nocturnal polygraphic study included a continuous recording of transcutaneous Sao2. The behaviour of oxygenation state during sleep was closely linked with the mean level of Sao2 during nocturnal wakefulness. Whatever the nocturnal period (wakefulness, non-rapid-eye-movement sleep, rapid-eye-movement sleep), the mean value of Sao2, which is an integration of variations of the oxygenation state, was more closely linked with diurnal Ppa than a single measure of Sao2 carried out during the catheterization. Ppa seemed independent of the amplitude and frequency of desaturation episodes. In patients with chronic obstructive lung disease, the measurement of mean Sao2 at rest is an easier investigation to carry out during diurnal wakefulness than during nocturnal wakefulness. Thus, this might allow the evaluation of the risk of developing permanent arterial hypertension in chronic obstructive patients.