HEMODYNAMIC AND ENDOCRINOLOGIC EFFECTS OF NONINVASIVE MECHANICAL VENTILATION IN RESPIRATORY-FAILURE

The aim of this study was to investigate the haemodynamic and endocrin ological effects of noninvasive positive pressure ventilation (NIPPV). Eleven patients with oedema and recent hypercapnic and hypoxaemic wor sening of a chronic respiratory insufficiency were included, Echocardi ography, cardiac radionuclide assessment, blood catecholamines,salt an d water handling hormones were measured at admission and discharge (lo ng study (LS)), To discriminate between the action of NIPPV and other treatments, measurements were performed on the fourth day, for 4 h wit hout NIPPV and 4 h with NIPPV (short study (SS)),NIPPV entailed a corr ection of Pa,CO2 and an increase of Pa,O-2 in LS and SS. Oedema disapp eared, Body weight decreased (from 85+/-42 to 81+/-40 kg) during LS. S ystolic and mean pulmonary arterial pressure decreased in LS and SS, R ight ventricular ejection fraction increased in LS, Left ventricular e jection fraction did not change, Cardiac index was normal on admission and then decreased, Natriuretic peptides and catecholamines were incr eased on admission, whereas plasma renin activity, aldosterone and vas opressin were normal, We suggest that in these patients, oedema can oc cur independently of renin-angiotensin-aldosterone-vasopressin and wit h a normal cardiac output, Noninvasive positive pressure ventilation a llowed a correction of blood gases, associated with the resolution of oedema, a decrease in pulmonary arterial pressures and an increase in right ventricular ejection fraction.