Vascular Dilation, Tachycardia, and Increased Inotropy Occur Sequentially with Increasing Epinephrine Dose Rate, Plasma and Myocardial Concentrations, and cAMP (original) (raw)
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Hemodynamic effects of epinephrine in rats: evaluation by impedance cardiography
2017
BACKGROUND AND OBJECTIVES This study was aimed to examine how inotropic effects of intravenously injected epinephrine change thoracic impedance measurements and to reveal the possible effects of this change on other hemodynamic parameters by using the technique of impedance cardiography. METHODS 10 male Wistar Albino rats were divided into two equal groups: control and epinephrine. 0.2 mg/kg of epinephrine was administered to the rats in the epinephrine group via the tail vein. All hemodynamic parameters obtained by impedance cardiography [the base impedance (Z0), the maximum rate of change in impedance (dZmax/dt), the left ventricular ejection time (LVET), stroke volume (SV), cardiac output (CO), contractility index (IC), thoracic fluid content (TFC), heart rate (HR)] were recorded using the EBI 100C, DA 100 and ECG modules in the BIOPAC MP100 system. RESULTS CO (p ≤ 0.05), HR (p ≤ 0.001), dZmax/dt (p ≤ 0.05) and IC (p ≤ 0.05) increased statistically significantly in the epinephrin...
BMC cardiovascular disorders, 2014
In current guidelines, prolonged cardiopulmonary resuscitation (CPR) mandates administration of repeated intravenous epinephrine (EPI) doses. This porcine study simulating a prolonged CPR-situation in the coronary catheterisation laboratory, explores the effect of EPI-administrations on coronary perfusion pressure (CPP), continuous coronary artery flow average peak velocity (APV) and amplitude spectrum area (AMSA). Thirty-six pigs were randomized 1:1:1 to EPI 0.02 mg/kg/dose, EPI 0.03 mg/kg/dose or saline (control) in an experimental cardiac arrest (CA) model. During 15 minutes of mechanical chest compressions, four EPI/saline-injections were administered, and the effect on CPP, APV and AMSA were recorded. Comparisons were performed between the control and the two EPI-groups and a combination of the two EPI-groups, EPI-all. Compared to the control group, maximum peak of CPP (Pmax) after injection 1 and 2 was significantly increased in the EPI-all group (p = 0.022, p = 0.016), in EPI...
Critical Care, 2021
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Demonstration of a different sensitivity to epinephrine in isolated and in vivo hearts
European Journal of Pharmacology, 1988
Studies in isolated preparations dealing with myocardial effects of catecholamines usually employ epinephrine concentrations 10-1000 times higher (10-7-10-5 M) than those observed during maximal cardiac adrenoceptor activation in vivo (10-9-5 x 10-8 M) to obtain measurable cardiac responses. The reason for this discrepancy is still unclear, but it may reflect a diminished sensitivity to catecholamines in vitro. The main purpose of this study was to evaluate if a different myocardial sensitivity to epinephrine in vivo and in vitro does exist and to investigate which epinephrine concentrations in vitro mimic the effect of cardiac adrenoceptor activation in vivo. We compared concentration-response curves to cumulative increasing concentrations of epinephrine, measured by high pressure liquid chromatography, in chloralose anesthetized or pithed rats (in vivo) and in isolated Langendorff perfused rat hearts (in vitro). We found that the amplitude of response to epinephrine was significantly higher in vivo at all concentrations. For example, an increase of 50 beats/rain was observed at an epinephrine concentration of 29 + 6 nM in chloralose anesthetized, 25 + 4 nM in pithed rats and 149 + 52 nM in isolated hearts (P < 0.05 vs. in vivo). Data on contractility closely parallel those on heart rate. These data indicate that, when methodological differences are minimized, there is a marked reduction in the amplitude of the response to epinephrine in vitro. This depressed response, which is not due to the absence of an intact central or peripheral innervation, implies that in vitro concentration of 5 x 10-7 M are required to mimic the effect of cardiac adrenoceptor activation in vivo. The physiological significance of even higher concentrations remains unclear.
Journal of applied physiology (Bethesda, Md. : 1985), 2016
Inotropic medications are routinely used to increase cardiac output and arterial blood pressure during critical illness. However, few comparative data exist between these medications, particularly independent of their effects on venous capacitance and systemic vascular resistance. We hypothesized that an isolated working heart model that maintained constant left atrial pressure and aortic blood pressure could identify load-independent differences between inotropic medications. In an isolated heart preparation, the aorta and left atrium of Sprague Dawley rats were cannulated and placed in working mode with fixed left atrial and aortic pressure. Hearts were then exposed to common doses of a catecholamine (dopamine, epinephrine, norepinephrine, or dobutamine), milrinone, or triiodothyronine (n = 10 per dose per combination). Cardiac output, contractility (dP/dtmax), diastolic performance (dP/dtmin and tau), stroke work, heart rate, and myocardial oxygen consumption were compared during...
International Journal of Psychophysiology, 1999
The effects of epinephrine administration on cardiovascular function were examined in 26 men who were given a bolus injection of either 1:10,000 epinephrine hydrochloride or physiological saline. Impedance cardiographic and continuous blood pressure measures were recorded during a 2-min pre-injection baseline and in the post-injection period. Compared to a saline control, epinephrine elicited greater shortening of heart period, pre-ejection period, and the R-B interval; greater increases in cardiac output, stroke volume, dZ/dt amplitude, Heather Index, and systolic and diastolic pressures; and greater decreases in total peripheral resistance (all P < 0.05). Left ventricular ejection time and the Q-R interval were not affected. The results indicate that inotropic indices that are readily measured by impedance cardiography should be considered as important non-invasive indices of adrenergically mediated responses to stress.
Anesthesiology, 2012
Background Myocardial depression is a frequent event during septic shock and may mimic a cardiogenic shock state with decreased cardiac output. Nevertheless, data are scarce regarding the myocardial effects of vasopressors used to treat hypotension. In this study, the authors compared the effects of three commonly used vasopressors acting on different adrenergic receptors on myocardial function in a rodent model of septic shock, as explored with conductance catheter and positron emission tomography. Methods Septic shock was induced in rats by peritonitis. Eighteen hours after septic insult, vasopressors were titrated to increase mean arterial pressure by 20% compared with baseline values. Results We observed that peritonitis was associated with arterial hypotension and systolodiastolic dysfunction. Norepinephrine and epinephrine improved mean arterial pressure, cardiac output, and preload recruitable stroke work, a load-independent measure of systolic function, as well as diastolic ...
Circulation, 1987
Although epinephrine has been shown to improve myocardial blood flow during cardiopulmonary resuscitation (CPR), the effects of standard as well as larger doses of epinephrine on regional myocardial blood flow have not been examined. In this study we compared the effects of various doses of epinephrine on regional myocardial blood flow after a 10 min arrest in a swine preparation. Fifteen swine weighing greater than 15 kg each were instrumented for regional myocardial blood flow measurements with tracer microspheres. Regional blood flow was measured during normal sinus rhythm. After 10 min of ventricular fibrillation, CPR was begun and regional myocardial blood flow was determined. Animals were then randomly assigned to receive 0.02, 0.2, or 2.0 mg/kg epinephrine by peripheral injection. One minute after drug administration, regional myocardial blood flow measurements were repeated. The adjusted regional myocardial blood flows (ml/min/100 g) for animals given 0.02, 0.2, and 2.0 mg/kg epinephrine, respectively, were as follows: