Dobutamine is considered as the first line inotrope for perioperative hemodynamic support in cardiac surgery by some of the classic references. What is your inotrope of choice? Have you stopped dobutamine due to adverse effects?
Dobutamine can not be considered as first choice inotrope after cardiac surgery. It is particularly useful where a high PVR is an important concern e.g. after mitral valve surgery. After CPB it increases CO mostly by increasing HR, action on SV is modest. However, ADR or Norad both increase SV and Adr is reported to increase HR less than dobutamine. IMO a combination of ADR and Norad after CPB may be a more logical inotrope as it will both increse SV with minimal tachycardia with a favorable CBF profile.
It really depends on the patient. I have found dobutamine to be very effective in patients with dilated cardiomyopathy. If you want a lot of alpha and a little beta, norepinephrine is useful. If you want only alpha, phenhylephrine is very effective.
In our current practice, we prefer dobutamine or norepinephrine as a first choice inotropic to support hemodynamics in cardiac surgical patients. The patient’s hemodynamics parameters play an important role in this selection. In a inquiry study from Germany, Kastrup et al. reported that epinephrine (41.8%) and dobutamine (30.9%) were the first-choice inotropic drugs for the treatment of low cardiac output syndrome, followed by phosphodiesterase inhibitors (14.5%). They also suggested that second-choice drugs for the treatment of low cardiac output syndrome were enoximone (29%), milrinone (25%) and dobutamine (25%) [Kastrup et al. Acta Anaesthesiol Scand 2007;51(3):347-358].
In our centre the first inotropic drug mainly used is Norepinephine; begining at very low doses (ie 0.02-0.05 µg/kg/min) mainly for vascular effects [norepinephrine 2mg in 50ml saline, begin at 2-5 ml/min] , dobutamine is used in 2d line when norepinephine level is superior to 0.1-0.2 µg/kg/min and cardiac output remain low (< 2l/min/m2) or blood pressure remain low (PAM< 50mm Hg).
This is to be modulated with preopérative cardiac status, for dilated cardiomyopathy, we go faster to dobutamin.
On 2d line the choice goes to epinephrine or milrinon / enoximon depending on peripheral and pulmonary vascular resistance analysis.
I will not discuss the pro and con of dobutamine or Norepinephrine ( NE) in this particular population, but i would like to know, when the Nantes group and Jean Rigal used NE at very low dose, they speak of NE BITARTRE or NE Base?
I think that norepinephrin can not be considered as an inotropic drug (in contrast to epinephrin) since it has no positive effect on SV or CI. The combination of norepi and dobutamine is very useful so you can titrate PVR and CI with two different agents. in cardiac surgery epinephrin is still commonly used even in patients with ischemic heart failure. Yet it has some adverse effects (arrhythmias, increased myocardial oxygen consumption...)
low dose epinephrine (0.025-0.05 mcg/kg/min) : no pro-arrythmic effect, no tachycardia, good improvement in CI and BP
The best inotropic drug in my view is oxygen. And therefore any drug improving delivery of oxygen to myocard cell could be the best inotrope So I think, in contrary to Maximilian, that NE could be considered as inotropic drug. In the set of anesthesia where lower pressure is common situation coul be the NE the drug of choice. As noradrenalin is coronarodilatator of both coronary art. and simultaneously increases the mean pressure which has an additive effect on coronary flow , bringing oxygen to myocardial cell.
On our unit we have moved to using enoximoe. A bolus of 0.25-0.5mg/kg (25-50mg) will rapidly increase the cardiac index and not normally be associated with severe vasodilatation. This is then followed up with an infusion of enoximone ( at up to 25mg/hr in the average patient. Patients that are vasodilated can be given norepinephrine infusion to counteract thhe vasodilatation. We consider norepinephrine to be a vasopressor rater than an inotrope although it appears to have soe inotropic effect in some patients.
We have found that dobutamine can be associated with dyssynchronous contraction of the ventricle leading to a reduction in blood pressure which is often assumed to be vasodilatation and associated with addition of norepinephrine infusion. This was found using TEE in a patient that was not responding to dobutamine and norepinephrien following cardiac surgery. On stopping the dobutamine, the blood pressure improved, as did the ventricular contractility, and we were able to reduce the norepinephrine infusion and extubate the patient a few hours later. Unfortunately, this a long time ago and do not have the echo pictures and we have never submitted a case report for publication. However, we changed our practice after this. I am sure any of you will be aware of patients that are not responding to dobutamine and norepinephrine on ICU and are deemed terminal. In some of these patients, the BP appears to improve when the dobutamine is reduced or stopped.
Well well well -
the point is what do I need the drug for......
1. if i have anesthetic side effects - low BP due to Propofol etc - and the rest of the heart is fine - NA is the drug of choice.
2. if I have low CO and adequate BP - the point is to increase CO with inotropic support and afterload reduction - dobutamine, milrinone, enoximoen etc are fine - and studies exist
3. if there is severe impaired CO - the use of adrenaline together with afterload reduction (i.e. milrinone, phenoxybenzamine, phentolamine, etc.) is the combination of choice - may be as an add-on to the things mentioned above
4. if there is low BP - needed for organ perfusion - some NA may be helpful if dobutamine lowers the BP too much
5. dopamine - especially low dose - is useless and only increases afterload and shows a good BP, only increases the rate of sepsis, impairs endocrine function, has no effect on kidney function, etc, etc,
here you are - open for discussion
Nik
No better inotrope than adequate preload as Frank Starling postulated some time ago. If fluid overload is present i would initiate Dobutamine as my forst choice.
Frankly Sirs, I definitely agree with the Niikolaus' point-by-point indications. Sorry Maximilian but I disagree when you say that NE is not an inotropic drug. Me personally, I had good results with it when LV contractility was worsening, especially in the postop patient with complex CHD.
Eventually, please let me add a 6th point to the ones by Nikolaus:
- dopamine /= 5 mcg, especiallly in the newborn infant moreover if with septic shock.
Depsite the recent concerns in the literature I think that they are far from being thrown out of the window so far.
Take care
Claudio
I agree with Nicolaus. But sometimes is it more complex. In cardiac surgery You can have a patient with poor RV contractility overloaded after CPB and after the use of predominantly vasopresor like noradrenalin or phenylephrin you can see increased contractility of the RV -"surprisingly" ( because of better perfusion through RCA) , which on the other hand better fills the LV and according to FS the contractility of the LV rises. So with alfa agonist You get both without any other action.
Therefore I don't really like something like do that if this ...... I thing we should really understand what happens in our patient for that is the echo and knowledge of pathophysiology substantial. So, dear Xose if contractility is low and fluid overload is present not always is Dobutamine my first choice :-). I have mentioned it before sometimes oxygen in myocardial cell is the best inotrope .
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