LVAD 2018

So patients with left ventricular assist devices are basically patients with cardiovascular disease. So most of these individuals do have coronary disease or heart failure.

So they can have any of the emergencies that you could have with a normal cardiovascular patient. They can have arrhythmias, they can have myocardial infarctions. But the added unique feature is now they can have complications of their pump, and that's what makes this patient population unique. So you can have the mechanical pump failing, but you got to remember they still have their native heart. That's why they're called the cyst devices. These patients can have strokes because these patients are in anticoagulation. And as a result of their anticoagulation, they can also have bleeds. So the most common venues that you're going to. Let me introduce you to the concept of an lvad. LVAD stands for left ventricular assist device. So these are basically pumps that drain blood from the tip of the heart, then have a pump that spins and then have another cannula that goes to the aorta. So blood can go in the heart and out, or through this pump and out. There are two main manufacturers, these pumps. One is the HeartMate 2, which is made by Thoratech. The other one is called the HVAD or heartwar, which is made by Medtronic. They're very similar in function. They're slightly different in construction. The HeartMate 2 has a cannula that drains blood out of the heart and then to the pump and then to the aorta, whereas the HVAD is stuck right in the tip of the heart and right to the aorta. Logistically, you won't see any of that. But that's the internal difference between these two pumps. They're both active axial flow, meaning they provide continual blood flow. So with regard to any type of left ventricular assist device, the assessment is the same. What makes them unique is there's non pulsatile flow. These pumps pump at a constant speed and are always expelling blood as opposed to your heart. Squeezing, resting, squeezing, resting. Because of that, the assessment's slightly varied from a normal person in that you're not going to be able to assess a pulse in the normal fashion of palpating one in the neck or in the arm or in the leg, because it will be a constant pressure and hence your fingers can't palpate that. Neither can your dynamaps or blood pressure cuffs sense the difference between systole and diastole because it's the same Pressure. See, with these patients, that's unique to this population, one is the pump may fail. Two, these people can have strokes or bleeds translating into strokes or GI bleeds. They can also have infections of where the mechanical drive line comes out. And so those are the common issues that you're going to see or complications. Now, they also have heart failure, so they can manifest with right heart failure, since these pumps do support the left side and not the right side of the heart. So if you're concerned that you have an unresponsive patient, first make sure that you examine the patient. So it's the patient first, not the device. So assess their alertness, because you may not feel a pulse, and they may look like they're dead, but they may be just sleeping. So first thing is just try to rattle them and ask if they're okay. The next assessment that really needs to happen is the pump functioning. And the way to start this is just put your stethoscope at the tip of the apex of the heart, either the left upper quadrant of the abdomen or literally at the bottom of the left lower quadrant of the chest where the apex of the heart is. And you should hear a humming sound. If you hear this humming sound, the pump is active and working. If you do not hear the humming sound, then there may be a mechanical dysfunction with the pump. The other thing is these pumps are intelligent technologies that give you information. So they do require power, and that's the major limitation. And they have a controller telling you if they have power and they're functioning. So after you auscultate to see if they have a hum or not, and then that decides a decision tree that the pump is working or is not working. The next step is really to assess do they have power to the pump if it's not working, make sure that the batteries are connected. And then the connections from the batteries to the controller that runs the pump is connected as well as from the controller to the pump itself that these connections are intact. If they're not, then we'll demonstrate how to place the batteries to make sure that the pump can start running. And make sure you auscultate to see if this is truly running. And then really it's looking at the controller which will tell you if there is a dysfunction of the pump. Now, if the pump is working, then you approach these patients just as you would approach any patient in terms of assessment. So if the pump is working, but you feel they're unresponsive or you think they may have had a stroke, they may have had hypoglycemia or whatever, then you really need to approach that no differently than you normally would. If you feel they have an arrhythmia that's causing them problems, you may cardiovert them, you may defibrillate them, and that does not have any interaction with the pump. But before you do that, the thing that you should assess is, is the flow adequate? A lot of these patients don't need cardioversion or defibrillation because the pump really doesn't care about electrical activity. So if the electrical activity, the arrhythmia is causing hemodynamic instability, and you'll know that because a pump will tell you its flow is reduced, then feel free to put the pads where you normally put the pads, feel free to shock them or do as you need it. So the question arises, does this patient need acls and or chest compressions? You should not always expect a pulse, but you may have a pulse if the fit pump has failed. And that basically assumes that their own heart has taken over the job. So if you put a dynamap or a blood pressure cuff and it gives you a number, you can trust the number. If you're not registering one, then you cannot trust that data. So the next step would be if you feel that the pump is failed and the patient is inadequately perfused, the next step is really assess your end tidal CO2. If you deem that it's low and the patient is under perfused, then you would perform ACLS as standard with a few modifications. With regard to.

If there is a need or an indication to do chest compressions, that you are aware that the chest compressions may dislodge the outflow cannula of the pump which rides right underneath the sternum. So what we would recommend if you need to, in a last ditch effort to support this patient to realizing that you can dislodge this cannula, is be slightly to the right of the sternum and make sure your chest compressions are really compressing about an inch to an inch and a half, mainly supporting the rv. As you're doing this, somebody needs to listen to the pump as well because you may see it.

Make a noise as it is gearing up. So with regard to chest compressions, as we've already suggested, make sure you're slightly to the right of the sternum, primarily supporting the rv, not the lv because the pump is on the LV side. With regard to, you can't be overly vigorous with your chest compression. So don't go as hard and deep to break bones, if you will. The Lucas device is out because it's very rigorous, it's a great device, but in this population there is a higher probability of dislodgement or trauma to the pump. So you really should be very cautious in approaching it that way and you really should engage in manual chest compressions.

So there are a few differences and exceptions when it comes to resuscitation in a patient with the left ventricular assist device. So if in a last case resort emergency that you have to provide ACLs and chest compressions, there are a few modifications from a standard patient. And so we just want to demonstrate this. In a standard patient, you would be right over the sternum doing your chest compressions at the appropriate frequency at about an inch and a half.

In venue. But because the driveline of the pump as well as the cannulas are directly underneath the sternum, you have to be cautious about dislodging or lacerating that sternum cannula. So as a result, what we tend to do is we go slightly to the right of the sternum, again compress about one to one and a half inches, provided that we're not breaking ribs at the appropriate frequency as indicated by acls. And that's the only slight modification that we do make with regard to using the Lucas device or other support devices. They're a little over vigorous or with regard to causing rib fractures and sternal.

Trauma, and hence we don't utilize them in patients with left ventricular assist devices.