Vasopressors M5/TL

Question 1

alpha 1 adrenergic stimulation causes constriction of …, …., …. and contraction of …, which all consistent with fight/flight response and therefore, its effect on metabolism is ….

Answer 1

BV, bronchus, sphincter,and ciliary muscle (mydraisis).

Urtine contraction.

suppressed insulin and lipolysis.

Question 2

Why CO is slightly decreased with the large increase of afterload (vasoconstriction) with with alpha 1 agoinist meds?

Answer 2

Mild intopy resulted from cardiac alpha receptors stimulation.

Question 3

Will Neo causes coronary vasoconstriction and feared to be administered in CAD?

Answer 3

Coronary arteries to left ventricle is only pressure during diastole (when aorta diastole pressure > LVEDP) and when Decreasing HR.

Neo accomplishments both
- yes it can constrict coronary but the metabolic vasodilator (NO) easily override the weak vasoconstriction

Question 4

Pressor of choice to preserve kidney function in sepsis

Answer 4

NorEpi

Not dopamine

Question 5

The reason of NorEpi gtt became first of choice in sever hypotension compared to dopamine is

Answer 5

Associated with lower rates of arrhythmias

Question 6

Catecholamines metabolites?

Answer 6

VMA

It’s breaker down by COMT and MAO.

Patients on MAOI should theoretically need lower doses

Question 7

Dobutamine works on both beta receptors and only one alpha receptor?

Answer 7

Beta agonist and alpha-1 agonist

Question 8

Press that will increase CO with minimal HR change ….

And … increases HR the most.

Answer 8

Dobutamine.

Isoproterenol

Question 9

Dromotropic Vs chronotrophy effect?

Answer 9

Conduction speed of electrical impulses within the heart.

Chronotrophy refers to HR.

Question 10

Lusitropy vs inotropy

Answer 10

Lusitropy is the process of myocardial relaxation during diastole

Intoropy; contractility

Question 11

Tachyphlaxis of ephedrine caused by …

Answer 11

Depletion of presynaptic NorEpi

Question 12

Beta receptor stimulation leads too …. which converts ATP to …

Answer 12

Gs protein -> Andenylate cyclase -> Converts ATP to cAMP -> increase Ca

Question 13

Milrinone MoA?

Answer 13

It inhibits the enzyme thatmetabolize cAMP and therefore keeping Ca levels high intercellular.

The enzymes phosphodiesterases

Causing vasodilation, decrease preload and afterload. Increases intropy, lusitropy and chronotrophy

Question 14

Inhaled vasodilator to lower pulmonary artery pressure is

Answer 14

Nitric oxide (not nitrous; it increases plum artery pressure).

Nitric has minimal effect on systemic pressure because it metabolized quickly

Question 15

Nitric oxide MoA ?

Answer 15

(+) guantlate cyclase -> increasing cGMP -> relaxes smooth muscle and vasodilation

(cGMP broken down by 5th isoform phosphodiesterase, which is sildenafil inhibits it)

Question 16

Milrinone MoA

Answer 16

Causes SM vasodilation and decreases PVR by increasing intercellular cAMP

Selective PDE III inhibitor which impairs breakdown of cAMP and therefore increases intracellular cAMP -> leads to increased influx of intracellular Ca -> cardiac ionotropy

Question 17

When Gulcagon considered therapy for low CO states

Answer 17

• following cardiopulmonary bypass.
• following MI
• chronic CHF
• low CO from excessive BB
• anaphylaxis shock with refractory hypotension

Question 18

The pressor that should not be given IM, only through central line?

Answer 18

NorEpi

It causes local ischemia necrosis given its alpha receptors stimulation&raquo_space; beta leading to potent vasoconstriction

Phentolamine solution of 5-10 mg in 10-15 NS decreases the degree of necrosis if happened.

Question 19

Why Ephedrine can be given IM when compared to NorEpi and what’s the dose/action time?

Answer 19

Because it’s not a direct vasoactive and will not cause loca ischemi.

0.5-0.6 mg/kg increases BP and HR within 10-15 min from time of injection

Question 20

Can phenylephrine given IM?

Answer 20

Yes because it’s less potent than NorEpi and causes venoconstriction&raquo_space; arterial constriction.

Dose: 2-5 mg raises BP and lowers HR within 10-15 min from injection.

Question 21

Vasodilator that can increase RBF?

Answer 21

Fenoldopam is a selective dopamine-1 agonist that increases renal blood flow.

Question 22

At lower dose of dopamine (0.5 to 3 mcg/kg/min) primarily acts on … and produce …

Answer 22

D-1 dopamine receptors to produce vasodilation of the renal, mesenteric, and coronary vasculature. The main result is an increase in the glomerular filtration rate and renal blood flow. Furthermore, low dose dopamine will result in sodium excretion which will increase urine output.

Question 23

Moderate doses of dopamine ( 3 to 10 mcg/kg/min) will stimulate the … and produce …

Answer 23

beta-1 receptors to increase release of norepinephrine from sympathetic nerve terminals. The end result is an increase in heart rate, systolic blood pressure, and pulse pressure. Diastolic blood pressure is minimally affected however pulmonary vascular resistance may increase.

Question 24

Highest doses of dopamine ( >10 mcg/kg/min) will stimulate the … and produce …

Answer 24

alpha-1 receptors which results in peripheral vasoconstriction.

Question 25

Side effects of dopamine depend on the dose and the patient’s comorbid conditions. Dopamine can cause …

Answer 25

tachyarrhythmias and myocardial ischemia.

At higher doses a decrease in splanchnic blood flow may occur with resultant gut ischemia.

Dopamine infusions may alter endocrine and immune functions including decreased secretion of thyroid stimulating hormone, prolactin, and growth hormone.

Dopamine decreases the ventilatory response to hypoxemia and hypercarbia secondary to exertion of a depressive effect on the carotid bodies.

Furthermore, dopamine may impair regional ventilation/perfusion matching in the lung, potentially causing or worsening hypoxemia.

If dopamine is extravasated, it can result in skin necrosis and sloughing thus administration into a central line is recommended. If extravasation does occur, prompt infiltration of the area with phentolamine and/or application of topical nitroglycerin should be considered to counter the vasoconstriction.

Question 26

Glucagon MoA?

Answer 26

Glucagon activates adenyl cyclase to increase cyclic AMP levels. Glucagon increases cardiac index, mean arterial pressure, and ventricular contractility.

Question 27

Intraoperative hypotension refractory to first line measures such as fluids, ephedrine, phenylephrine, and glycopyrrolate, think of? whats the most effective treatment?

Answer 27

Patients who continue ACEi/ARB on day of surgery.

Reversed with either norepinephrine or vasopressin, but only norepinephrine will do so while maintaining cardiac output and gastric perfusion.

Question 28

Milrinone Effects:

• Intropy through …
• vasodilation through …

Answer 28

1) Cyclic AMP Effect: Inotropy
- Increases contractility (inotropy), heart rate (chronotropy) and conduction velocity (dromotropy).
- Increased cardiac output.
2) Cyclic AMP Effect: Vasodilation
- Smooth muscle relaxation.
- Decreased left ventricular end-diastolic pressure.
- Improves pulmonary blood flow and left ventricular filling.

Question 29

The cardiovascular effects of milrinone can be summarized as:

Answer 29

increased inotropy
increased lusitropy
increased CO, SV, and EF

decreased afterload
decreased preload

pulmonary vasodilation, and systemic vasodilation.