Quiz 3 Flashcards
Septic:
Increased CI, Decreased PCWP, Decreased SVR
Hypovolemic
Dec CI, Dec PCWP, Inc SVR
Cardiogenic
Dec CI, Inc PCWP, Inc SVR
cAMP Dependent positive inotropes
- Beta Agonists
- Dopaminergic Agonists
- Phosphodiesterase Inhibitors
cAMP independent positive inotropes
- Cardiac Glycosides
- Calcium
Look at slide 11-12
.
Drug highest risk of tachyarrhythmias?
Isoproterenol
then Epi, Dopa, Dobutamine
Prototypical catecholamine Stimulates
Alpha-1, Beta-1, and Beta-2 receptors
Low dose Epi
-Stimulate alpha-1 receptors in the skin, mucosa, and hepatorenal system while beta-2 receptors are stimulated in skeletal muscle
- Beta-2 effects in peripheral vasculature predominate.
- The net effect is decreased SVR and distribution of blood to skeletal muscle
- MAP remains essentially the same
-Essentially a vasodilator.
Intermediate dose Epi
- Inotrope
- Increased H.R. and contractility and increased C.O.
- Inotropic activity.
- Increased automaticity
- May lead to dysrrhythmias (PVCs) in sensitized myocardium
High dose Epi
- Most potent activator of Alpha-1 receptors
- Potent vasoconstrictor including cutaneous, splanchnic and renal vascular beds
- Used to maintain myocardial and cerebral perfusion
- Increases Aortic dBP.
- Reflex bradycardia can occur
- Vasoconstrictor.
Norepi: Cardiac output may ______ at low doses, but at higher doses may ________ because of increased afterload and baroreceptor-mediated reflex bradycardia
increase
decrease
Catecholamine Complications
- Local tissue ischemia from SQ infiltration of inoconstrictors.
- Increased myocardial oxygen consumption
- Enhance lipolysis and gluconeogenesis
- Alter electrolyte concentrations
- Activate coagulation
- Override microvascular control mechanisms
- Alter distribution of CO
- Increase myocardial work
- Increase the risk of cardiac arrhythmias
Isoproterenol
- Beta-1 and Beta-2 Receptor Effects (No Alpha-1 effects)
- Increases HR , contractility, B.P., and cardiac automaticity
- Decreases SVR and diastolic BP
- Net effect is increased C.O. and decreased M.A.P.
- Bronchodilator
Isoproterenol uses
- Chemical pacemaker after heart transplant or in complete heart block
- Bronchospasm management during anesthesia
- Maybe used to attempt to decrease PVR in patients with pulmonary hypertension and RV failure***
Synthetic catecholamine with structural characteristics of Dopamine and Isoproterenol
Dobutamine
Dobutamine
- Acts primarily on Beta-1 receptors with small effects on Beta-2 and Alpha-1 receptors.
- Less increase in conduction compared to isoproterenol.
- Less likelihood of adverse increase in myocardial O2 requirements.
- Dilates coronary vasculature.
- No dopaminergic receptor activation.
- Increases renal blood flow by increasing C.O.
_____________ interacts with itself at alpha receptors agonist and antagonist effects
Dobutamine
D-1 like receptors
- G coupled > stimulate adenylate cyclase > activate cAMP
- Smooth muscle of blood vessels: vasodilatation
- Naturesis, Diuresis
D-2 like receptors
- G coupled > inhibits AC > inhibits cAMP
- Presynaptic: Inhibit NE release and promote vasodilation
- Attenuate the beneficial effects of DA on renal blood flow
Dopamine Dose Dependent Effects
- 0.5-3 mcg/kg/min dopamine effect (DA1 and DA2)
- 3-10 mcg/kg/min beta effect
- 10-20 mcg/kg/min beta and alpha effects
- Over 20 mcg/kg/min alpha effects
Dopamine Receptor Effects
- DA1 stimulation produces vasodilatation in the renal, mesentery, coronary, and cerebral arteries
- Inhibit secretion of aldosterone
- Increases RBF, GFR, Na+ excretion and urine output
- BUT NOT RENAL PROTECTIVE
- Had been used a lot during periods of renal stress (aortic surgery, sepsis, resuscitation, CPB, and NE infusion)
Look at slide 40
.
__________ interferes with the ventilatory response to hypoxemia
Dopamine
Inhibitory role of DA at the carotid bodies.
