Elite Level Vasoactive & Receptor Pharmacology

Vocabulary flashcards covering mechanisms, clinical applications, receptor interactions, and CVICU caveats for key vasoactive and receptor pharmacology agents.

Norepinephrine (Levophed)

Pure Alpha-1 receptor agonist causing strong vasoconstriction in systemic arterioles, with mild Beta-1 receptor agonist activity (slight increase in inotropy/chronotropy); first-line agent to restore mean arterial pressure (MAP) by increasing systemic vascular resistance (SVR), particularly during vasoplegia post-cardiopulmonary bypass.

Epinephrine (Adrenalin)

Potent Beta-1 and Beta-2 agonist at low doses with Alpha-1 agonist effects dominating at higher doses; used for severe hemodynamic collapse or structural right/left ventricular failure post-bypass to aggressively spike heart rate (chronotropy), stroke volume (inotropy), and cardiac output.

Dopamine

Dose-dependent agonist hitting dopaminergic receptors at low doses ($0.5\text{--}2\text{ mcg/kg/min}$), Beta-1 receptors at medium doses ($2\text{--}10\text{ mcg/kg/min}$), and Alpha-1 receptors at high doses ($>10\text{ mcg/kg/min}$); less favored in CVICUs due to a high incidence of tachyarrhythmias such as atrial fibrillation.

Milrinone (Primacor)

Phosphodiesterase-3 (PDE3) inhibitor that blocks the breakdown of cyclic adenosine monophosphate (cAMP), increasing intracellular calcium influx in cardiac myocytes (positive inotropy) while relaxing vascular smooth muscle (systemic and pulmonary vasodilation); unloads the right heart in RV failure and pulmonary hypertension by lowering pulmonary vascular resistance (PVR).

Dobutamine

Strong Beta-1 agonist with mild Beta-2/Alpha-1 activity that boosts myocardial contractility and heart rate to augment cardiac index (CI) in pure cardiogenic shock; cleared renally and hepatically, making it safer in acute kidney injury (AKI).

Vasopressin (Pitressin)

Non-adrenergic vasopressor that directly stimulates V1 smooth muscle receptors in the vasculature, bypassing the adrenergic network; added when a patient is refractory to high-dose Norepinephrine or in systemic acidosis, without causing arrhythmias or pulmonary vasoconstriction.

Nitroprusside (Nipride)

Direct, ultra-potent venous and arterial smooth muscle relaxant via nitric oxide release that drops afterload instantly; carries a risk of thiocyanate/cyanide toxicity during prolonged or high-dose infusions, presenting as unexplained metabolic acidosis.

Nicardipine (Cardene)

Dihydropyridine calcium channel blocker and pure arterial vasodilator with zero effect on cardiac contractility; used for precise, smooth blood pressure reduction to protect fresh vascular grafts or aortic dissections.

Norepinephrine (Levophed)

Pure Alpha-1 receptor agonist causing strong vasoconstriction in systemic arterioles, with mild Beta-1 receptor agonist activity (slight increase in inotropy/chronotropy); first-line agent to restore mean arterial pressure (MAP) by increasing systemic vascular resistance (SVR), particularly during vasoplegia post-cardiopulmonary bypass.

Epinephrine (Adrenalin)

Potent Beta-1 and Beta-2 agonist at low doses with Alpha-1 agonist effects dominating at higher doses; used for severe hemodynamic collapse or structural right/left ventricular failure post-bypass to aggressively spike heart rate (chronotropy), stroke volume (inotropy), and cardiac output.

Dopamine

Dose-dependent agonist hitting dopaminergic receptors at low doses ($0.5\text{--}2\,\text{mcg/kg/min}$), Beta-1 receptors at medium doses ($2\text{--}10\,\text{mcg/kg/min}$), and Alpha-1 receptors at high doses ($>10\,\text{mcg/kg/min}$); less favored in CVICUs due to a high incidence of tachyarrhythmias such as atrial fibrillation.

Milrinone (Primacor)

Phosphodiesterase-3 (PDE3) inhibitor that blocks the breakdown of cyclic adenosine monophosphate (cAMP), increasing intracellular calcium influx in cardiac myocytes (positive inotropy) while relaxing vascular smooth muscle (systemic and pulmonary vasodilation); unloads the right heart in RV failure and pulmonary hypertension by lowering pulmonary vascular resistance (PVR).

Dobutamine

Strong Beta-1 agonist with mild Beta-2/Alpha-1 activity that boosts myocardial contractility and heart rate to augment cardiac index (CI) in pure cardiogenic shock; cleared renally and hepatically, making it safer in acute kidney injury (AKI).

Vasopressin (Pitressin)

Non-adrenergic vasopressor that directly stimulates V1 smooth muscle receptors in the vasculature, bypassing the adrenergic network; added when a patient is refractory to high-dose Norepinephrine or in systemic acidosis, without causing arrhythmias or pulmonary vasoconstriction.

Nitroprusside (Nipride)

Direct, ultra-potent venous and arterial smooth muscle relaxant via nitric oxide release that drops afterload instantly; carries a risk of thiocyanate/cyanide toxicity during prolonged or high-dose infusions, presenting as unexplained metabolic acidosis.

Nicardipine (Cardene)

Dihydropyridine calcium channel blocker and pure arterial vasodilator with zero effect on cardiac contractility; used for precise, smooth blood pressure reduction to protect fresh vascular grafts or aortic dissections.

Central Venous Pressure (CVP)

Normal range: $2\text{--}6\,\text{mmHg}$. Measured directly from the blue (proximal) port in the Right Atrium; serves as an indicator of right-sided preload and fluid volume status returning to the right heart.

Pulmonary Artery Pressure (PAP)

Normal range: $15\text{--}25 / 8\text{--}15\,\text{mmHg}$ (Mean: $10\text{--}20\,\text{mmHg}$). Measured continuously from the yellow (distal) port tip sitting in the Pulmonary Artery; reflects pulmonary vascular pressures and the workload the Right Ventricle must pump against.

Pulmonary Artery Wedge Pressure (PAWP / PCWP)

Normal range: $6\text{--}12\,\text{mmHg}$. Measured by inflating the balloon at the tip for less than $15\,\text{seconds}$ to look forward; represents left-sided preload and pressure in the Left Atrium and Left Ventricle at end-diastole.

Cardiac Output (CO)

Normal range: $4.0\text{--}8.0\,\text{L/min}$. Calculated as $\text{CO} = \text{Heart Rate} \times \text{Stroke Volume}$; represents the total volume of blood the heart pumps per minute.

Cardiac Index (CI)

Normal range: $2.5\text{--}4.0\,\text{L/min/m}^2$. Calculated as $\text{CI} = \frac{\text{Cardiac Output}}{\text{Body Surface Area}}$; adjusts raw output to the patient's unique body size.

Systemic Vascular Resistance (SVR)

Normal range: $800\text{--}1200\,\text{dynes}\cdot\text{sec/cm}^5$. Calculated as $\text{SVR} = \frac{\text{MAP} - \text{CVP}}{\text{CO}} \times 80$; represents Left Ventricular afterload and the resistance/clamping of the systemic arterial bed.

Pulmonary Vascular Resistance (PVR)

Normal range: $37\text{--}250\,\text{dynes}\cdot\text{sec/cm}^5$. Calculated as $\text{PVR} = \frac{\text{Mean PAP} - \text{PAWP}}{\text{CO}} \times 80$; represents Right Ventricular afterload and the resistance/tightness of the blood vessels inside the lungs.

Mixed Venous Oxygen Saturation (SvO_2)

Normal range: $60\%\text{--}80\%$. Measured continuously via fiberoptics at the catheter tip or drawn from the distal port; evaluates the oxygen supply vs. demand balance by measuring the percentage of oxygen remaining when blood returns to the heart.