Cardiovascular Effects of Dopamine in Developing Swine

Buckley, N. M.; Brazeau, Paul; Frasier, I. D.

doi:10.1159/000241637

Cited by 18 publications

(12 citation statements)

References 15 publications

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“…These observations support the theory of Gootman el a/. (40,41) and others (42) that in the postnatal period, vascular autonomic receptors mature at different rates (40), with the or adrenergic receptor being mature at birth, but the "dopaminergic" receptor requiring significant postnatal development.…”

Section: Effects Of Dopumine Infusionsupporting

confidence: 85%

The Effects of Dopamine Infusion on Regional Blood Flow in Newborn Lambs

et al. 1987

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ABSTRACT. The purpose of this project was to investigate the effects of high rates of dopamine infusion on cardiac output and regional blood flow in the lamb. We studied eight unanesthetized newborn lambs (mean age 7 + 2 days) during a 15-min baseline period and while infusing dopamine at 5-, 20-, 80-, and 160 pg/kg/min. We measured cardiac output and mean aortic, pulmonary arterial and left atrial pressures, and organ blood flow using radionuclidelabeled microspheres at each rate of dopamine infusion. Cardiac output increased significantly with increasing rates of infusion up to 80 pg/kg/min but decreased at 160 pg/kg/ min. Aortic, pulmonary arterial, and left atrial pressures increased at rates of infusion above 5 pg/kg/min. Blood flow to all organs was unchanged at the 5 pg/kg/min rate of infusion of dopamine while blood flow to the brain and heart increased at the 80 pg/kg/min rate of infusion and blood flow to the gut and kidney decreased. We conclude that dopamine is an effective inotropic agent in the newborn lamb but that an inotropic:afterload mismatch exists at high infusion rates. Despite an increase in cardiac output at low rates of infusion, dopamine did not selectively vasodilate the vascular bed of any organs tested. Furthermore, at high rates of infusion dopamine actually impaired blood flow to the gut and kidney. (Pediatr Res 21: 131-136, 1987) Dopamine remains an extensively used catecholamine in the management of shock in critically ill infants and children (1). We recently studied the effects of dopamine on hemodynamics in 2-to 3-wk-old lambs and found it to be an effective inotropic agent (2). However, inherent properties of neonatal myocardium may render it relatively unresponsive to the inotropic actions of dopamine and the same effects may not occur in the younger lamb. In the clinical setting, myocardial immaturity may prompt the use of rates of infusion of dopamine in excess of those currently recommended (1). The effects of high rates of infusion on regional blood flow in the newborn are unknown.The purpose of our study was to investigate the effects of dopamine on regional blood flow in newborn lambs over a wide range of infusion rates. We hypothesized that in the newborn lamb dopamine would not increase cardiac output at conventionally used rates of infusion but might at higher rates. At these higher rates, however, we anticipated that the a-adrenergic effect of dopamine would compromise blood flow to vital organs. MATERIALS AND METHODSSurgical preparations. We operated on eight lambs using halothane and nitrous oxide anesthesia delivered by a piston type ventilator. From a left hindlimb cutdown we inserted polyvinyl catheters into a peripheral artery and vein and advanced them into the descending aorta and inferior vena cava, respectively. We also inserted a 3.5 Fr thermistor wire (Edwards Laboratories, Inc., Irvine, CA) into a peripheral artery by separate hindlimb cutdown and advanced it into the descending aorta. Finally, we placed a polyvinyl catheter in a forelimb artery and ad...

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Section: Effects Of Dopumine Infusionsupporting

confidence: 85%

The Effects of Dopamine Infusion on Regional Blood Flow in Newborn Lambs

et al. 1987

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“…Interestingly, the renal response to low-dose dopamine is age dependent in animals. This is interpreted as a maturation process of renal dopamine receptors (6)(7)(8). However, premature neonates with respiratory distress syndrome receiving 2 pg/kg/min of dopamine increased their natriuresis compared to a matched control group not treated by dopamine (28).…”

Section: Discussionmentioning

confidence: 99%

“…A considerable amount of data supports its use in adults (1-5) but hemodynamic and renal effect of dopamine have not yet been assessed in children. Some animal (6)(7)(8) and clinical studies (9) suggest that differences in response to dopamine exist between adults and pediatric patients.…”

mentioning

confidence: 99%

Effect of Low Dose Dopamine on Hemodynamic and Renal Function in Children

et al. 1989

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ABSTRACT. The purpose of the study was to investigate the effect of low doses of dopamine in children. Fourteen cases were studied after open heart surgery. Cardiac output and renal parameters were determined under baseline conditions and under continuous infusion of dopamine 2.5 and 5 ~g/kg/min. During the control period cardiac index was 2.62 f 0.19 L/min/m2, renal plasma flow was decreased at 269 f 41 mL/min/1.73 m2, GFR was 86.6 2 9.2 mL/min/ 1.73 m2, and filtration fraction was elevated at 37.1 f 1.9%. Plasma concentration of aldosterone correlated with the filtration fraction. At 5 pg/kg/min dopamine increased significantly cardiac output, renal plasma flow, and to a lesser extent GFR, thus decreasing the filtration fraction. At 2.5 pg/kg/min dopamine, increased renal plasma flow only in patients older than 5 y and had no effect on the other parameters. The increase of cardiac output in response to dopamine was abolished by propanolol pretreatment. By contrast, the hemodynamic renal response to dopamine was not altered by P-blockade. These results indicate that 5 wg/kg/min of dopamine could prevent renal failure after open heart surgery in children by increasing renal blood flow and attenuating renal compensatory mechanisms. (Pediatr Res 26:200-203,1989) Abbreviation PAH, para-aminohippurateIn the presence of reduced cardiac output, dopamine is frequently used for both its positive cardiac inotropic and its renal vasodilatory effects. A considerable amount of data supports its use in adults (1-5) but hemodynamic and renal effect of dopamine have not yet been assessed in children. Some animal (6-8) and clinical studies (9) suggest that differences in response to dopamine exist between adults and pediatric patients.After open heart surgery, cardiac output and systemic pressure are often depressed. Renal failure develops in 3 to 20% of patients depending on the criteria used and the patient population. It markedly influences the ultimate prognosis (10-1 5).Our study was designed to test the effect of a continuous infusion of dopamine, 2.5 and 5.0 pg/kg/min, on hemodynamic and renal function in children after open heart surgery. renal function before the operation. The group consisted of eight girls and six boys aged 18 mo to 15 y. The clinical characteristics and the preoperative plasma creatinine concentrations are given in Table I. All the patients had normal urinalysis with negative or trace proteinuria. Before the operation, six children with tetralogy of Fallot were treated with 1 to 4 mg/kg/day of propranolol to prevent hypoxic spells; the drug was stopped 8 h before the beginning of the operation. The surgery was performed with cardiopulmonary bypass, deep hypothermia (1 8 to 24"C), and moderate hemodilution (20 to 30%).Cold chemical cardioplegia was used to obtain asystole. When cardiopulmonary bypass was discontinued, blood was infused until the left atrial pressure reached 9.5 to 12.5 mm Hg, and a single dose of furosemide (1 mg/kg) was given.Method. After the operation, a Swan-Ganz catheter (5 F...

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“…Renal vasoconstriction was noted in young swine, whereas vasodilatation occurred in older animals after a-and P-adrenergic receptor blockade. Bucky et al (16) observed renal vasoconstriction in swine younger than 1 month even after a single, low, intravenous dose of dopamine unless a-adrenergic receptors were blocked by phentolamine. In addition, they evaluated the regional circulatory effects of dopamine infused into developing swine and suggested that the developmental time course of dopamine receptors differed from the particular regional circulation (1 7).…”

Section: Discussionmentioning

confidence: 99%

Maturation-Related Changes in Dopamine-Induced Relaxation of Isolated Rabbit Pulmonary Artery

et al. 1988

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ABSTRACT. Studies were performed on isolated pulmonary arterial segments to investigate dopamine receptormediated relaxant effects at different times during development. Dopamine receptor-mediated relaxant effects can only be observed when vessels are precontracted with prostaglandin Fz, and in the presence of al, ag P, and serotonergic blockade. Helical strips of pulmonary arteries from rabbits of different ages (2, 7, 14, 30, and 90 days), partially precontracted by prostaglandin Fz, were tested for their responses to dopamine in the presence of prazosin M), yohimbin M), propranolol M), and methysergide M). Strips from 2-and 7-day-old rabbits were not induced to relax by dopamine, whereas those from 14-, 30-, and 90-day-old animals, after cumulative application of dopamine, underwent concentration-dependent relaxation. Dopamine (half the maximum response) concentration decreased during the development of rabbits from 14 to 90 days old. Mean values for apparent dopamine ED50 (half the maximum response) concentrations in the arteries of 14-, 30-, and 90-day old animals were 4.94 + 0.40, 2.02 + 0.30, and 0.113 + 0.028 wM, respectively.The effects of various dopamine antagonists on dopamineinduced relaxation were not markedly different at different ages. These findings indicate that dopamine receptor function is not fully developed in the pulmonary arteries of newborn rabbits, but matures as the age of the rabbit increases. (Pediatr Res 24: 160-165, 1988) Abbreviations ED50 concentration, concentration that produced half the maximum response pAz value, the negative logarithm of the molar concentration of the antagonist that produces a 2-fold shift to the right of the dose-response curve for the agonist Dopamine stimulates PI-adrenergic receptors causing positive inotropy and has been used to treat shock and congestive heart failure. In high doses, it also stimulates al-adrenergic receptors causing vasoconstriction. In low doses, however, specific dopaminergic receptors mediate vasodilation.In the cardiovascular system specific dopaminergic receptors are found in renal, mesenteric, splenic, coronary, cerebral, and femoral arteries. A vascular dopaminergic receptor classification has been proposed by Goldberg and Kohli (1, 2), in which the DA, receptor subserves smooth muscle relaxation, and the DA2 Received December 29, 1987; accepted March 18, 1988. Correspondence Dr. Miyako Mori, Department of Anesthesiology, Kobe University School of Medicine, Kusunoki-cho-7, Chuo-ku, Kobe, 650 Japan.Supported by grants from the Ministry of Education, Japan.receptor subserves the inhibition of noradrenaline release from postganglionic sympathetic nerves. Previously, we confirmed the existence of DAI dopamine receptors in the adult rabbit pulmonary artery (3). Dopamine produced a concentration-dependent relaxation of arterial strips contracted with prostaglandin F2, in the presence of prazosin (al-blocker), yohimbin (a2-blocker), propranolol (P-blocker), and methysergide (serotonin-blocker). The pulmonary circulatory system un...

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Cardiovascular Effects of Dopamine in Developing Swine

Cited by 18 publications

References 15 publications

The Effects of Dopamine Infusion on Regional Blood Flow in Newborn Lambs

The Effects of Dopamine Infusion on Regional Blood Flow in Newborn Lambs

Effect of Low Dose Dopamine on Hemodynamic and Renal Function in Children

Maturation-Related Changes in Dopamine-Induced Relaxation of Isolated Rabbit Pulmonary Artery

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