Norepinephrine
Norepinephrine is a catecholamine with a high affinity for alpha receptors. It is primarily used to increase systemic vascular resistance. Norepinephrine can enhance coronary perfusion during severe hypotension and should stabilize blood pressure until further cardiac treatments are initiated.
Norepinephrine benefits patients with low blood pressure and inappropriate vasodilation (low blood pressure with normal or high cardiac output). It must be given through a central venous line to prevent tissue necrosis from extravasation.
Vasopressors, such as phenylephrine, norepinephrine, and vasopressin, also increase afterload. Afterload refers to the total resistance to the ejection of blood from the ventricle during contraction. Increasing afterload results in decreased extent and velocity of myocardial contraction.
Norepinephrine mainly increases blood pressure in heart failure by raising systemic vascular resistance, with minimal impact on cardiac output. Its use is restricted to patients with severe hypotension or complicating conditions like sepsis due to the increased myocardial oxygen demand it causes.
Norepinephrine in patients with cardiogenic shock
The Comparison of Dopamine and Norepinephrine in the Treatment of Shock (SOAP II) trial compared norepinephrine and dopamine in 1,679 patients with various shock causes.
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The primary outcome showed no difference in survival at 28 days between patients treated with norepinephrine or dopamine. However, dopamine was linked to significantly higher arrhythmia rates (24% compared to 12.4% for norepinephrine), e.g., atrial fibrillation. Additionally, there was a higher incidence of severe arrhythmia with dopamine (6.1%) versus norepinephrine (1.6%).
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In a pre-defined subgroup of patients with cardiogenic shock, comprising 280 patients (16.7%), dopamine use was associated with a notably increased mortality rate.
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Based on this study's findings, norepinephrine is recommended as the preferred vasopressor for patients with cardiogenic shock.
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In my pinion, due to various mechanisms of heart failure, norepinephrine is the preferred vasopressor for managing shock in acute pulmonary embolism, critical pulmonary hypertension, and in combination with inotropic agents for left ventricular failure. For patients with valvular heart disease, my preference depends on the hemodynamics associated with the valve condition. For instance, in cases of severe mitral valve stenosis caused by rheumatic disease, I usually prefer beta-blockers. In cases of valve regurgitation, I prefer arterial vasodilators with or without inotropic agents for hemodynamic support before valve interventions.
Norepinephrine in patients with septic shock
Norepinephrine in patients with acute pulmonary embolism
Norepinephrine in patients with right ventricular failure due to pulmonary hypertension
Comparative effects of dopamine(pink) and dobutamine (blue) on heart rate, pulmonary capillary wedge pressure, and total systemic vascular resistance in patients with moderate to severe heart failure.
Dopamine is a less useful agent for the treatment of heart failure because its effects result in tachycardia, coronary vasoconstriction, increased afterload, and increased oxygen consumption.
Dopamine increases heart rate at higher doses.
Dopamine increases pulmonary capillary wedge pressure at higher doses.
Dopamine increases systemic vascular resistance at higher doses.
dobutamine
dobutamine
dobutamine
Modified from Leier CV. Regional blood flow responses to vasodilators and inotropes in congestive heart failure. Am J Cardiol. 1988;62:86E
References
David L. Brown (Eds.). (2019). Cardiac Intensive Care (3nd ed.). Elsevier. https://doi.org/10.1016/C2014-0-03291-1
Leier CV. Regional blood flow responses to vasodilators and inotropes in congestive heart failure. Am J Cardiol. 1988 Sep 9;62(8):86E-93E.
De Backer Daniel, Biston Patrick, Devriendt Jacques, Madl Christian, Chochrad Didier, Aldecoa Cesar, et al. Comparison of Dopamine and Norepinephrine in the Treatment of Shock. New England Journal of Medicine. 362(9):779–89.
Chen HH, Anstrom KJ, Givertz MM, et al. Low-Dose Dopamine or Low-Dose Nesiritide in Acute Heart Failure With Renal Dysfunction: The ROSE Acute Heart Failure Randomized Trial. JAMA. 2013;310(23):2533–2543.
Parrillo, Joseph E.; Dellinger, R. Phillip. Critical Care Medicine E-Book: Principles of Diagnosis and Management in the Adult (Kindle Locations 29221-29222). Elsevier Health Sciences. Kindle Edition.
Anastasiadis, Kyriakos; Westaby, Stephen; Antonitsis, Polychronis. The Failing Right Heart . Springer International Publishing. Kindle Edition.