The effect of continuous positive pressure in the nasal airway on the right ventricular function in obstructive apnea sleep syndrome

BACKGROUND: The aim of this study was to evaluate the right ventricular function in the obstructive apnea sleep syndrome (OSAS) and to determine the effect of the continuous use of a continuous positive pressure nasal device on the airway (CPSPn) produces on this aspect of the disease. METHODS: Forty patients were diagnosed of OSAS by study of spontaneous night sleep. A functional respiratory study was performed in all the patients as was a calculation of the index of body mass (IBM) and isotopic ventriculography for the calculation of the right and left ventricular ejection fractions (RVEF and LVEF). Twenty-six patients were followed after 8.4 +/- 3.3 months of home treatment with CPAPn in which these studies were repeated. RESULTS: Twenty-four of the 40 patients (60%) had RVEF lower than 0.45. These 24 patients had paO2 in vigil state (69.9 +/- 13.6 mmHg) than those with a normal RVEF (80.1 +/- 8.7 mmHg) (p < 0.05). After treatment with CPAPn an elevation was observed in the RVEF in the group which was followed. This increase was significant in the subgroup sharing low RVEF (n = 16) prior to starting treatment upon passing from 0.39 (+/- 0.02) to 0.45 (+/- 0.04) (p < 0.001). CONCLUSIONS: Right ventricular dysfunction in frequent in patients with the obstructive apnea sleep syndrome and is more frequent in patients maintaining hypoxemia in vigil. The continual use of continuous positive pressure in the nasal airway produces improvement in right ventricular function particularly in those in whom this was most disturbed.