What Makes the Ventricular Assist Device So Special? -

What Makes the Ventricular Assist Device So Special?

You and your family are sitting at the Food Court at a local mall as you hear a woman frantically screaming, “Call 911!” Having recently just undergone first aid training, you get out of your chair and saunter over to the commotion. There you find a middle-aged man slumped over at his table. As another bystander activates the 911 system, you begin to assess the status of the man. He’s not breathing and does not appear to have a carotid pulse. After enlisting the help of another person nearby, you lower the man to the ground to start chest compressions, when his wife scolds you, “He has a VAD! Don’t do CPR!” This goes against everything you’ve been taught this far, but you honor the wife’s wishes, and wait for EMS to arrive and take control of the scene. So, what is a VAD, and why is it so important?

VAD stands for Ventricular Assist Device. It was invented in the mid-1980s, and has been in common usage since the early 1990s. The VAD is only appropriate for a small percentage of people; unfortunately, due to its rarity, it’s rarely ever covered in CPR or pre-hospital training. The majority of the public that has a VAD wear what appear to be suspenders with battery packs resting on each hip. If you allow me to digress, I will momentarily delve into how the VAD works. As you know, the heart is broken up into four different quadrants: the right atrium, the right ventricle, the left atrium, and the left ventricle. The ventricles tend to carry the heavier part of the workload, so ventricular failure is often looked upon as drastically serious. The right ventricle feeds into the pulmonary valve and into the lungs to become oxygenated; the left ventricle pumps into the aortic valve and into the aorta to disperse blood throughout the body. Essentially, there are three different VAD devices: the right ventricular assist device (RVAD), the left ventricular assist device (LVAD), and the BIVAD (a combination of the RVAD/LVAD). This device ensures that the blood remains oxygenated, as well as maintaining blood production to the rest of the body.

So why the uproar about performing chest compressions on someone that appears to be in cardiac arrest? The main reason behind this is, that chest compressions and the VAD do the same job. You are trying to circulate blood through the body, or to be technical, become an artificial left ventricle. Secondarily, there is fear that overzealous chest compressions could dislodge the VAD leading to major life-threatening complications, especially, if chest compressions were being provided to someone that was not in full cardio-respiratory arrest. Thus begs the question, then what do we do? The majority of VAD devices should have a manufacturer number on the side of the battery pack. When you call this number, there should be an operator that instructs you whether or not you can perform chest compressions or defibrillate this patient. If the number is not available, you are going to need to do some critical thinking, and quickly.

Many of the older VAD devices have a hand pump that act as fail safe; it’s not nearly as effective, but it is better than nothing. Remember that hand pumping the device should be roughly the same rate as normal chest compressions during CPR. Newer devices will not have a hand pump, so you may have to do some trouble-shooting. In the heat of the moment, we tend to overlook the obvious. Does everything look like it is plugged in? Is there a light flashing indicating a dead or dying battery? Green lights are your best friend in this situation; if the light is green the VAD is working. Secondly, there should a “buzz”; this will be the engine whirling, also indicating that it is functioning. If the machine is quiet, the VAD has malfunctioned and no blood is being pumped at all. Lastly, does the box feel hot to the touch? When the box feels hot, this means that the VAD is being overworked, and this can happen for a plethora of reasons. Unfortunately, none of these reasons can be fixed without an emergency room and possibly a surgeon, so we will stay away from those right now.

Now that we’re done playing auto mechanic, what next? If you have checked out all of the possibilities and the patient is still presenting to be in cardiac arrest, you need to start chest compressions. If you’re in the pre-hospital setting, obviously airway management and cardiac monitoring is paramount, and should have been long ago, but I would like to point out that sometimes even the basics can be overlooked in stressful situations. If a shockable rhythm presents, you need to still defibrillate the patient. When in doubt, perform standard CPR until instructed otherwise. A recent study was just conducted in 2012, following eight VAD patients that experience cardiac arrest. All eight received standard chest compressions, defibrillation, and ACLS medications. Not a single patient had their VAD dislodged. Eight patients is a significantly small sample size, but this study should bolster our confidence.

So to recap, here is how we treat the unconscious, pulseless, apneic VAD patient. Support the airway first, just as you would any other patient. If available, place the patient on a defibrillator or cardiac monitor. Is there a phone number on the VAD for online support of how to treat the patient? Call it. Is there any indicator the VAD is not working? If you can fix it, do just that. If not, it is good old-fashioned CPR. VADs are no different than any other scenario; with a little bit of education and experience, the fear of taking action dissipates.

 

Resources:

Bellezzo, J., Cheskes, S., Chillcott, S., Dembitsky, W., Shinar, Z., & Stahovich, M. (n.d.). Chest compressions may be safe in arresting patients with left ventricular assist devices (LVADs). Resuscitation, 5(85). doi:May 2014

Weingart, S. (Director) (2012, July 8). Left Ventricular Assist Devices (LVADS). EmCrit.

What Is a Ventricular Assist Device? (2012). National Heart, Lung, and Blood Institute. Retrieved from http://www.nhlbi.nih.gov/health/health-topics/topics/vad#