Dopamine infusion in patients with hepatic encephalopathy: plasma levels and haemodynamic changes.

During a constant infusion of dopamine (DA 4.5 micrograms/kg/min), the plasma levels of DA reached at 30 min of infusion were 81 +/- 6.9 ng/ml and 71.6 +/- 14.8 ng/ml in patients with hepatic encephalopathy (HE) and control patients, respectively. In both groups of patients, the plasma levels of DA did not change between 30 and 60 min of continuous DA infusion. The DA infusion was associated with an increase of arterial blood pressure, heart rate and cardiac index. In the patients with HE, the increase in cardiac index was directly correlated with the plasma level of DA (r = 0.843, p less than 0.01). The present results clearly demonstrate that in HE circulating DA does not accumulate during continuous infusion of DA. They further provide evidence that the increase in circulating catecholamines in HE reflects increased release from the sympatho-adrenal system.