Continuous Infusion Of Dopamine Research Articles

Increase in hepatic blood flow and cardiac output during dopamine infusion in man.

The object of this paper was to evaluate the effect of a continuous dopamine infusion (10--12 micrograms/kg . min) on the estimated hepatic blood flow (EHBF) and cardiac output (CO) in man. Measurements were made in 3 periods: the initial control state, during dopamine infusion, and after the infusion. The CO (by thermodilution) and EHBF (by hepatic vein sampling after continuous indocyanine green (ICG) infusion) were measured during each phase. Ten subjects, with inapparent hepatic disease, hemorrhage, or hemodynamic anomalies, were studied. The results showed a 64% increase in the EHBF and a 49% increase in the CO. All subjects showed a return to the original baseline state after infusion. The EHBF/CO was 14% in the control period, 17.3% during infusion, and 13.4% after dopamine infusion. These changes were not statistically significant. Dopamine, therefore, increased both EHBF and CO, but the existence of intrahepatic dopaminergic receptors could not be established.

Effect of dopamine and neuroleptics on plasma growth hormone and prolactin in normal men

(1) This study investigates further the locus of action of dopamine (DA) and DA antagonists in affecting growth hormone (GH) and prolactin (PRL) secretion in normal subjects. (2) Each of three normal men was tested twice with a continuous DA infusion (0.3 mg/min) over 90 min. (3) Mean plasma GH concentration was significantly ( p < 0.05) elevated above baseline at 30 min after onset of DA infusion. (4) The same subjects were also tested twice with the identical dose of a DA infusion after a single neuroleptic drug had been given i.v. 30 min earlier. This pretreatment with an antidopaminergic drug resulted in a significant delay and attenuation of the GH response to DA. (5) The elevated plasma PRL concentration induced by the neuroleptic was suppressed to baseline within 60 min after onset of the DA infusion. (6) Since DA does not cross the blood brain barrier (BBB) these findings indicate that GH secretion can be affected in normal men by dopaminergic mechanisms operating outside the BBB.

RESUSCITATION OF PRETERM INFANTS WITH EARLY POSTNATAL CARDIOVASCULAR SHOCK

This study was designed to evaluate the vascular compartment of infants born in the presence of maternal vaginal bleeding, and to describe one regimen for fluid and pharmacologic resuscitation. Eleven infants born to mothers with abruptio placentae exhibiting tachycardia (HR>150) and hypotension at 1 hr. age received empiric infusions of 20 ml/kg lactated Ringers solution (LR) and 20 ml/kg fresh blood. Blood volume (BV) determinations using the 51Cr RBC dilution technique were completed and BV deficits were then corrected by rapid transfusions of fresh blood. BV determinations were repeated and infants were given 1 μg/kg per min. continuous infusion of Dopamine if BV was normal and hypotension persisted.Eleven infants were studied and BV were markedly deficient as reflected in the mean red cell volume of 35 ml/kg (nl = 64), and mean total BV of 67 ml/kg (nl = 108). Two infants were infected (Group B strep, E. coli), and 2 infants remained hypotensive following BV restoration with a second transfusion. The infant with Strep infection and 1 infant given Dopamine expired.We conclude that preterm infants with hypotension resulting from abruptio placentae are markedly volume deficient and that proper management of these babies required BV determinations. Although early resuscitation with LR is efficacious (survival = 82%), treatment with Dopamine requires further evaluation.

Sustained complete autonomic blockade.

1. A 3-hr period of complete autonomic blockade was induced in anaesthetized sheep and dogs using a continuous intravenous infusion of trimetaphan camphorsulphonate and atropine. Circulatory, respiratory and metabolic parameters were studied over 24 hr or until the animal died, whichever came first.2. After termination of the blockade all animals remained hypotensive and within a few hours all died in irreversible shock which was not accompanied by any of the otherwise characteristic respiratory or metabolic consequences of circulatory failure.3. Administration of trimetaphan alone for a similar period was innocuous.4. When during complete autonomic blockade a continuous infusion of dopamine or hypertensin was additionally administered mortality rate was halved but all survivors remained hypotensive.