- See:
- Inotropic Agents
- Inotropic agent (not vasoconstrictor);
- Useful in pt w/ poor CO output, elevated left ventricular filling pressures (PAOP > 18mm Hg), & marginal systemic blood pressures;
- For Shock syndrome as result of MI, endotoxins, trauma, Renal failure;
- Selective B1 stimulator;
- Causes direct iotropic stimulatorwith reflex vasodilation & increase CO;
- SBP remains constant;
- Causes less Tachycardia than Dopamine
- at higher doses, beta-2 activity increases, resulting in Tachycardia and peripheral vasodilation;
- w/ high systemic vascular resistance, dobutamine dose can be increased to give beta 2 mediated arterial vasodilation;
- Use w/ Myocardial Infarct:
- dobutamine's lack of induction of endogenous Norepinephrine minimizes its effect on myocardial oxygen demand;
- when titrated to avoid significant increases in heart rate, dobutamine does not increase infarct size or elicit arrhythmias;
- heart rate may decrease as hemodynamics improve;
- since vasodilation occurs in response to increased cardiac output, blood pressure may change very little;
- hence, dobutamine is agent of choice w/ hemodynamically signficant Rt. ventricular infarction;
- Dosage:
* infused at 2.5 - 10 ug/kg/min (Diluted: 250mg/250ml of D5W);
* maximum dose of 30 ug/kg/min
- must decrease dosage if SBP > 130mm Hg
- note Tachycardia ( > 10% may get Ischemia) and ectopic ventricular beats, evaluate BP, volume status;
* dopamine and dobutamine have been used together;
- combination of moderate doses of both drugs maintain arterial pressure better with less of an increase in wedge pressure and, thus, less pulmonary congestion than dopamine alone;
- Precautions:
* Must correct hypovolemia Before use, consider Swan Ganz;
* Decrease dosage with MAOI use;
* Note Dobutamine produces little vaso-constriction at usual doses and has no role in the absence of spontaneous circulation; Check BP & HR