Home / the ABCs of VADs : Answers

the ABCs of VADs : Answers

 

Case review: an unconscious unresponsive patient with no carotid pulse. During application of AED pads, you notice this.

  1. What is this device? 
  2. How does it work?
  3. Do I continue with my immediate resuscitation?
  4. Should this device cause me to modify my resuscitation efforts?

 

This is a VAD (ventricular assist device).  A ventricular assist device (most often a left ventricular assist device –LVAD) is a mechanical pump that is connected to the left ventricle at, or near the apex and to the ascending aorta. It continuously pumps blood from the left ventricle to the rest of the body. Heart transplantation remains the definitive therapy for patients with advanced heart failure; however, owing to limited donor organ availability and long wait times, left ventricular assist devices (LVADs) have become standard therapy.

 Currently, the most common LVADs being implanted in the United States are second- and third-generation devices, the HeartMate II (Thoratec Corp., St. Jude Medical) and the HeartWare HVAD (HeartWare International, Inc.). A newer third-generation pump, the HeartMate III (Thoratec Corp., St. Jude Medical), is designed to create an artificial pulse and is currently under investigation in the United States.

The system has 4 parts: The pump, the driveline, the controller and the batteries.

 

The pump is internal and pulls blood from the left ventricle into the pump and then sends it to the ascending aorta which then sends the blood to the rest of the body. The driveline is internal and external. It connects the pump to the controller and contains the electrical and power cables and exits the skin on the right or left side of the abdominal wall. The controller is external and operates the pump. The controller may have lights, messages or alarms if the power is low or the pump is not functioning properly.

 

 

System Controller

 

 

Batteries: When asleep, patient’s need to plug their LVAD into an external AC power source. When outside the home, they need to have fully charged batteries. These batteries, depending on the specific VAD,  can be in a pack carried with the controller or in a holster carried over the shoulder.

 

Physical assessment in the altered or unconscious patient with an LVAD:

by Zach Shinar, MD and Joe Bellezo, MD from EDECMO

When assessing the patient with an LVAD these patients may not have a palpable pulse.  Auscultate the chest to see if the motor is working and check the controller for low battery or low flow status.

Look, listen and feel.

Look: Look at all the connections. is everything connected?  Look at the controller. Is the Green Light on?  No? Troubleshoot for a problem with the VAD and keep working until you get the green light on the controller.

Listen: to the hum. Assuming a green light on the controller…there should be an LVAD Hum. No hum? the pump isn’t functional. Find out why. Again, check all the connections and then touch the control box and check RPM, flow, etc. Pump thrombosis is your reversible problem here.

Feel: hot control box is not good and usually means thrombosis or dislodgement of the outflow cannula to the aorta…or a distal obstruction like a dissection.

Compressions: here is my thought: if you’ve gone through all of the above and there is nothing to fix…then you have an LVAD patient who does not have a functional LVAD. I would treat them just as if they came to the ED the day before they got their LVAD: a patient with end-stage heart failure and no blood pressure. I would begin chest compressions if their MAP was below 60 because they aren’t perfusing their vital organs and will die. I know this goes against Zack’s recommendations but that shows you that nobody really knows the best answer here. This patient will die. I say start the chest compressions and get inotropes going. Dobutamine or milrinone stat in addition to levophed. In other words…pretend they don’t have a VAD and aggressively resuscitate them. Yes, dislodging the pump is possible…but these patients are going to die anyway.

 

Here are some helpful algorithms to use in the resuscitation of the LVAD patient.

 

 

MOST patients have a tag located on the controller around their waist that says what type of device it is, what institution put it in and a number to call. Most importantly is the color of the tag – it matches this EMS Field Guide and allows you to quickly locate the device you are caring for.

 

If you remember anything from this post, please click this image link and download or save this PDF file which includes step-by-step guides for troubleshooting each of the 6 VADs listed. 

 

 

 

Dr.Scott Weingart’s EMCrit LVAD Podcast

with Zack Shinar, MD

 

 

 

 

 

Want to read more…?

EMCrit : Left Ventricular Assist Devices (LVADS)

ALIEM : Academic Life in Emergency Medicine. PV Card: LVAD Complications

REBELEM: Left Ventricular Assist Device

emDocs: LVAD patients. What you need to know?