HAEMODYNAMIC EFFECTS OF DOPAMINE AND DOPAMINE COMBINED WITH NITROGLYCERIN IN PATIENTS SUBJECTED TO CORONARY BYPASS SURGERY

The haemodynamic effects of dopamine and dopamine with nitroglycerinwere evaluated in eight patients with coronary heart diseasewho underwent aortocoronary bypass surgery. The study was performedunder anaesthesia and before surgery. Dopamine 8 µg kg^–1min^–1 alone produced a marked increase of the cardiacindex from 2.47 to 3.47 litre min^–1 m^–2 but onlysmall changes in heart rate (from 65 to 68 beat min^–1).This improvement in cardiac performance was accompanied by anincrease of the mean pulmonary artery pressure from 10.9 to21.3 mm Hg and in the left ventricular filling pressure from6.1 to 13.8 mm Hg with unchanged systemic and pulmonary vascularresistance. Mean arterial pressure increased from 72 to 103mm Hg. Simultaneous infusion of dopamine (8 µg kg^–1min^–1 and nitroglycerin (mean dose 0.5 µg kg^–1min^–1) resulted in a favourable reduction of mean pulmonaryartery pressure (from 21.3 to 14.4 mm Hg) and of left ventricularfilling pressure (from 13.8 to 7.9 mm Hg). Cardiac index (from3.47 to 3.34 litre min^–1 m^–2) and mean arterialpressure (from 103 to 95 mm Hg) were not reduced to the sameextent by the addition of nitroglycerin. The combined treatmentof dopamine with nitroglycerin seems to be of value in patientswith pre-existing high lseft ventricular filling pressure orwith pulmonary hypertension.