SHORT-TERM ACE-INHIBITION HAS NO EFFECT ON SODIUM AND WATER-EXCRETIONDURING PEEP VENTILATION

The short-term effect of intravenous (i.v.) angiotensin converting enz yme (ACE) inhibitor enalaprilat in 10 critically ill patients, being v entilated with positive end-expiratory pressure (PEEP), on sodium and water excretion was investigated. Mean arterial pressure (MAP) decreas ed. Heart rate and central venous pressure (CVP) did not change. Glome rular filtration rate (GFR), urine volume (V) and sodium excretion (UN aV) decreased in two patients with reduced MAP. GFR, V and UNaV increa sed in two patients with decreased MAP. No relation between changes in MAP and excretion was observed in six patients. ACE decreased in all patients. Plasma renin activity increased, aldosterone decreased, whil e atrial natriuretic peptide as well as antidiuretic hormone did not c hange. Enalaprilat did not facilitate sodium and water excretion durin g ventilation with PEEP. Decreased MAP indicates that the investigated patients were very dependent on their renin-angiotensin system to mai ntain systemic perfusion pressure. Base-line MAP and CVP values were n o predictors of haemodynamic and excretory changes following acute ACE inhibition.