CARDIORESPIRATORY EFFECTS OF CONTINUOUS IV ADMINISTRATION OF THE ACE-INHIBITOR ENALAPRILAT IN THE CRITICALLY ILL

1 Cardiorespiratory effects of long-term, continuous i.v, administrati on of the ACE inhibitor enalaprilat were studied. 2 Forty-five consecu tive critically patients suffering from trauma or postoperative compli cations were randomly separated into three groups (15 patients in each up) receiving either 0.25 mg h(-1) or 0.50 mg h(-1) enalaprilat, resp ectively, or saline solution as placebo (= control group). The infusio n was continued for 5 days. 3 Haemodynamic and respiratory parameters were intensively monitored on admission to the intensive care unit (= 'baseline' values) and daily during the next 5 days. 4 Mean arterial b lood pressure (MAP) decreased significantly only in the enalaprilat-tr eated patients, whereas heart rate (HR) remained unchanged in these pa tients. 5 Pulmonary capillary wedge pressure (PCWP) and pulmonary arte ry pressure (PAP) were decreased by enalaprilat (0.50 mg h(-1): PAP (m ean +/- s.d.) decreased from 28.0 +/- 4.1 to 24.0 +/- 3.0 mm Hg) and r emained significantly lower than in the control group. In the untreate d control group, cardiac index (CI), oxygen consumption (VO2I) and oxy gen delivery (DO2I) significantly decreased, which was blunted by enal aprilat infusion. Oxygen extraction (O-2-extr) increased in both enala prilat groups (0.25 mg h(-1): from 26.1 +/- 5.5 to 30.4 +/- 4.0%; 0.50 mg h(-1): 25.2 +/- 5.6 to 30.9 +/- 4.4%) and decreased in the control patients. 6 Right ventricular haemodynamics improved by enalaprilat i nfusion (0.50 mg h(-1): RVEF increased from 40.0 +/- 3.5 to 45.5 +/- 4 .0%). Lactate plasma concentrations decreased in the group with 0.50 m g h(-1) enalaprilat (from 1.9 +/- 1.0 to 1.3 +/- 0.3 mg dl(-1)) and in creased in the control patients. 7 Continuous infusion of the ACE inhi bitor enalaprilat exerted beneficial cardiorespiratory effects in the critically ill. The widespread common risk of altered perfusion with d ecreased CI, DO2, VO2, O-2-extr and increased lactate concentration wa s blunted by enalaprilat infusion. 8 Although 0.5 mg h(-1) enalaprilat was most effective, a dose of 0.25 mg h(-1) also showed beneficial ha emodynamic effects in the critically ill.