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The efficacy and tolerance of a nasal CPAP device marketed in France (Pression +, Sefam) for the treatment of obstructive sleep apnoea syndromes have been evaluated in a co-operative trial including 12 patients. This study confirmed the efficacy of nasal CPAP on sleep parameters: total sleep time was increased; light non-REM sleep was diminished; slow-wave sleep and REM sleep were augmented; sleep apnoeas were eliminated completely or almost completely; oxygen saturation was markedly improved. At one month follow-up, most clinical features were improved; daytime blood gases showed little change but the number of red cells was decreased. On the whole, the tolerance was good in this highly motivated group of patients: eleven patients (92%) were willing to continue their home treatment with the same device. Most difficulties were due to the making of a tailored molded nasal mask and its use during sleep.

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.

The purpose of this study was to assess the relationship between the breathing pattern response to CO2 and the severity of mechanical impairment in twenty patients with COLD. The CO2 response was compared to that of a control group of twelve normal subjects. All patients had airway obstruction (FEV1 = 40 +/- 14% of predicted; means +/- SD) and hyperinflation (FRC = 154 +/- 23% of predicted). Tidal volume (VT), inspiratory and total cycle duration (TI, TT), occlusion pressure (P0.1) and endtidal PCO2 were measured at rest and during hyperoxic CO2 rebreathing. On the same day, in all patients, arterial blood gas analysis, spirometric and plethysmographic measurements were made. The slope (S) of the P0.1 response (SP 0.1) to increasing endtidal PCO2 was negatively correlated with airway resistance (r = -0.59; p less than 0.01). Although the flow response, S(VT/TI), was positively and closely correlated with SP 0.1 (r = 0.88; p less than 0.001), it also appeared to be independently influenced by obstruction (p less than 0.01). The tidal volume response, SVT, was principally correlated with inspiratory capacity (r = 0.90; p less than 0.001) and also, independently, with Vmax50 (p less than 0.01). SVT was diminished in seventeen patients, ten of whom only had a decreased S(VT/TI). The shortening in TI during hypercapnia was most marked in patients with the greatest S(P0.1), who did not have arterial hypercapnia at rest. These results suggest: that the poor VT response to CO2 in COLD patients is principally caused by a limitation in inspiratory volume expansion.(ABSTRACT TRUNCATED AT 250 WORDS)