Milrinone or Dobutamine?

Milrinone or Dobutamine, which one is best for cardiogenic shock? As an Intensivist at a cardiovascular ICU is probably the most common question asked, and let me walk you through and my approach to this. The best evidence we have is from the DORAMINE trial done at the Ottawa Heart Institute, is where I trained, and they enrolled 192 patients, double blinded to get dobutamine or milrinone in milrinone in acute cardiogenic shock. The trial actually did not show any difference in their primary outcome of death, resuscitated cardiac arrest, receipt of a cardiac transplant or mechanical circulatory support, nonfatal myocardial infarction, transient ischemic attack or stroke diagnosed by a neurologist, or initiation of renal replacement therapy. Secondary outcomes included the individual components of the primary composite outcome. But what I found interesting about the trial is that it held beliefs in the CV ICU. One that dobutamine causes more which they which they didn't see, and causes more hypotension, which not not see significant differences in their primary outcome of death, cardiac arrest, MI, mechanical circulatory support, and stroke. But what I found interesting about the trial is that it challenged two commonly held beliefs in the CV ICU. One that dobutamine causes more arrhythmias, which they didn't see, and milrinone causes more hypotension, which they did not see significant differences of arrhythmias, hypertension, lactate clearance, and ICU length of stay. And the reason I find it interesting it challenges what my anecdotal experience has been with both of these agents. As astute clinicians, we must review the nuances of this trial. The first is that it was a single center study only. So it limits generalizability. Second, they enrolled less than 200 patients. So they were only powered relatively large treatment between the two agents. Meaning smaller yet clinically meaningful differences between the inotropes could have been missed by this trial. And this is why experts see this trial informative one, but it doesn't have word on this matter. So who gets what? So, how do I decide which patient gets which inotrope? Typically, if the patient's hypotensive, hypoperfused, I reach for dobutamine first. It's got a shorter half-life, it's easier to titrate, and it's not affected by renal impairment, which a lot of our cardiogenic shock patients do have. However, if the patient has severe RV dysfunction, pulmonary hypertension, or is chronically on beta blockers, then I reach for milrinone, because it'll improve the RV function, you'll get pulmonary vasodilation, and it works outside of the beta receptors, as long as their blood pressure can tolerate initial vasodilation. And if you're someone who likes milrinone, one thing to note is that renal impairment will increase the concentration of it. So it can be difficult to titrate, it can last longer, and will be difficult to predict its effect as you titrate it. One last thing is if the patient is not improving rapidly and is still hypoperfused, we're now moving towards mechanical circulatory support. So this is like putting an Impella in. There's a trial ongoing right now and we'll await the results of this. So if your patient is not improving, don't hesitate to put in an Impella. And remember, the question asking yourself is not which medication is better. The question is, which physiology am I treating? And this is the question I ask myself for every patient I see in the CVICU.