THE EFFECT OF CONTINUOUS POSITIVE PRESSURE IN THE NASAL AIRWAY ON RIGHT-VENTRICULAR FUNCTION IN THE OBSTRUCTIVE APNEA SLEEP SYNDROME

BACKGROUND: The aim of this study was to evaluate the right ventricula r function in the obstructive apnea sleep syndrome (OSAS) and to deter mine the effect of the continuous use of a continuous positive pressur e nasal device on the airway (CPSPn) produces on this aspect of the di sease. METHODS: Forty patients were diagnosed of OSAS by study of spon taneous night sleep. A functional respiratory study was performed in a ll the patients as was a calculation of the index of body mass (IBM) a nd isotopic ventriculography for the calculation of the right and left ventricular ejection fractions (RVEF and LVEF). Twenty-six patiens we re followed after 8.4 +/- 3.3 months of home treatment with CPAPn in w hich these studies were repeated. RESULTS: Twenty-four of the 40 patie nts (60 %) had RVEF lower than 0.45. These 24 patients had paO2 in vig il 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 obse rved in the RVEF in the group which was followed. This increase was si gnificant 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 patien ts with the obstructive apnea sleep syndrome and is more frequent in p atients maintaining hypoxemia in vigil. The continual use of continuou s positive pressure in the nasal airway produces improvement in right ventricular function particularly in those in whom this was most distu rbed.