LVADs: Not Just for Big People Anymore

Until recently left ventricular assist devices (LVADs) were used exclusively for the dying and nearly dead. That is not the case anymore. Until recently transporting patients with LVADs required a full critical care team. That also is not the case anymore. And until recently LVADs were only for adults. That, too, is not the case anymore! 

Here’s a short, sweet, real-life review for treating those increasingly common patients with these devices.

When the Heart Needs Help

How to support the sick and diseased heart has long plagued medical providers. Evolving treatments, from pharmacotherapeutics to mechanical circulatory devices, have been targeted toward remodeling the heart for better function. Since the 1960s the LVAD has been one of several mechanical devices utilized to enhance the function of otherwise sick and dying hearts.

A ventricular assist device (VAD) is a manmade electromechanical pump implanted in either the right or left ventricle (or both) that assists the heart in circulating blood. Our primary focus for this article is the LVAD, which pulls blood from the left ventricle and pumps it to the aorta. The aorta then distributes the oxygenated blood throughout the body. Without the assistance of pump, a patient whose heart muscle is too weak to push the necessary amount of blood to the body will experience heart failure. With an LVAD the heart’s pumping action is augmented so the demands of the body are met and homeostasis maintained.

The key components of a VAD are the pump (implanted in the heart) and an external controller connected to the pump via a driveline. The pump and controller are both AC- and DC (battery)-operated. Though there are several different manufacturers of VADs, they all have the same basic components and operate similarly.

Abbott’s HeartMate II and HeartMate 3 and Medtronic’s HeartWare are the most common LVAD types implanted in the U.S. and will likely be what EMS personnel encounter most frequently. There are likely still a few older-generation VADs out there, but we wouldn’t expect them in the pediatric population. Of note, children’s hospitals across the world are now implanting HeartMate and HeartWare VADs in children as young as 7. VADs are not just for big people anymore!

Assessment First

As with anything in EMS, a solid assessment is required when caring for a patient with an LVAD. This is a time when treating both the patient and the equipment is essential. Assessing one but not the other can lead to critical failures.

The LVAD is working if you see a green light on the controller or hear an audible mechanical hum over the heart. The hum naturally will be loudest in the area of the left ventricle, but it should be easily audible if your stethoscope is anywhere on the chest—especially for pediatric patients with small chest areas. The newest LVADs have digital screens with a constant display of readings as well as loud audible alarms.

Know the basics of how an LVAD operates. The first-generation pumps were pulsatile, with systolic and diastolic pressure changes. Second-generation and newer pumps are referred to as continuous-flow and typically have no pulsatile pressure changes. Instead they have a continuous pressure (set by maintaining a specific range of revolutions per minute) to meet the patient’s demands. 

Knowing which style pump your patient has will be one way to figure out whether you will be able to palpate a pulse. You might not expect a patient who has a continuous-flow LVAD to have a palpable pulse. However, if that patient also has an ejection fraction (EF) of 25% or more (normal is 60%–70%), you may be able to palpate one. If a patient’s ejection fraction is but 5%, you probably won’t feel a pulse at all. 

With this in mind, let’s talk more about palpating pulses.

Palpating Pulses

Pulseless and talking are two words rarely found in the same line of an assessment. But when an LVAD is working, some patients (adults and kids) may not have a palpable pulse, and that’s OK.

On the other hand, if your patient presents with no pulse and no talking and no noise from the LVAD, that’s a bad sign. When the LVAD is not operating (no hum can be auscultated) due to pump or power failure, the patient will probably appear dead. A monitor will probably show v-fib or asystole, and there will be no spontaneous breathing and little or no exhaled EtCO₂ on capnography. 

If this happens, treat this patient as you would any other with the same presentation. Initiate high-quality chest compressions, secure the airway, and provide medications and therapies per protocols. If ROSC is achieved and the patient reaches the emergency department, call a pediatric cardiology consult immediately to evaluate the LVAD.

Compressions pose a significant risk of the dislodging the device and causing internal bleeding and potentially death. That is an understandable risk. But despite the potential damage chest compressions may cause, not doing compressions in a pulseless patient is certainly not recommended. 

Blood Pressure

Generally, a continuous-flow LVAD pulls blood from the failing left ventricle through a pump and then pushes the blood into the aorta. Patients with an LVAD have a seriously sick left ventricle, and the LVAD may be providing a large majority of their cardiac output. As such, there will be little to no pulse pressure (difference between the systolic and diastolic BP). This is why palpating a pulse on these patients can be nearly impossible, and pulse pressures tend to be small. 

Understand that for these patients, the important blood pressure number is not the systolic or diastolic pressure or even the pulse pressure. Since the heart is not creating effective pressure through its intrinsic pumping, the pressure we are most concerned about is the mean arterial pressure (MAP) maintained by the LVAD.

If you’re using any sort of device to monitor noninvasive blood pressure (NIBP) on your LVAD patient, it may detect a blood pressure (usually with a really narrow pulse pressure) and a fairly normal mean arterial pressure. For example, you might see a BP of 72/68 with a MAP of 67. But it will only do so if the heart is able to outpump the LVAD flow. A measure of the heart’s pumping strength is called the ejection fraction. If a blood pressure is measurable, the EF might be in the range of 30%. If the EF is lower, an automatic BP machine may only give you a MAP reading or possibly no reading at all. This is due to the lack of a strong pulsatile flow. With this knowledge, we can understand why the gold standard recommendation is to check at least one (or, even better, two) manual Doppler BPs to verify the accuracy of the MAP.

Without an arterial line in place (rarely seen in EMS or at triage) and with automatic blood pressure machines not always being much help, what’s an EMS provider to do? Go back to basics and take a good old-fashioned manual blood pressure (but with a Doppler). For a patient with an LVAD, a manual Doppler BP reflects the patient’s MAP. Place an appropriate-size cuff on the patient’s arm and place the Doppler on the same spot as you would a stethoscope, over the brachial artery in the antecubital fossa. Inflate the cuff until the Doppler pulse is no longer heard. As the pressure on the cuff is slowly released, the first sound heard will be the Doppler BP. For the LVAD patient this is the MAP. 

With the newer generation of LVADs, it is recommended to average two Doppler blood pressures. This is because some newer LVADs (like the HeartMate 3) have alternating rates of RPMs, so an initial MAP may be different than one taken shortly thereafter. 

If a Doppler is not available, an automatic noninvasive blood pressure machine may provide a relatively accurate estimate of the MAP. With the increasing number of LVADs in our population, we urge all EMS services to include this helpful tool to their inventory.

Pulse Oximetry

Just as palpating a pulse or checking a Doppler BP can aid in the assessment of the LVAD patient, pulse oximetry can help as well. Be aware that pulse oximeters may or may not work—most LVAD patients don’t have a palpable pulse, so getting a pulse ox to work accurately can be difficult. If a pulse ox is picking up a signal and it appears to be normal, it is probably correct. However, if the pulse ox isn’t picking up well or seems low, it may not be accurate. In every case assess your patient as well as the equipment.

Common EMS/ER Issues 

The most common EMS/ER issues for LVAD patients are: 

• Thrombosis/clot;
• Dehydration/hypovolemia;
• GI bleed;
• Brain bleed;
• Driveline infection;
• Pump failure/got unplugged/battery died (leading to asystole).

A few pearls for treating these problems:

VAD center—Most tertiary hospitals have VAD coordinators. This person can be your best friend, so keep their contact information handy. 

Alarms—If an LVAD is alarming, check the connections first. Figure 1 is a handy reference to LVAD alarms.

Just say yes—Yes, you can give ACLS and PALS medications. You can cardiovert. You can defibrillate. You can externally pace. You can perform manual CPR. You can place and use a LUCAS, AutoPulse, or other mechanical CPR device. 

IV fluids—VADs love volume. If the patient looks sick, chances are a bolus of normal saline or lactated Ringer’s might help, at least temporarily.

Low-flow states—To remember some of the common causes of low-flow states, consider the mnemonic SHABDORC:

• S—Sedation or sepsis
• H—Hypertension
• A—Arrhythmia
• B—Bleeding (25% are GI in nature)
• D—Dehydration
• O—Overdrive (LVAD speed is too fast)
• R—Right heart failure
• C—Clot

BOD CRASH covers the same information in an order that may be easier to remember. 

Power, driveline, power—If you need to change an LVAD controller, it must always remain attached to at least one battery. Change one battery while keeping the other attached. This should only be done if there is a hardware fault or as directed by a VAD coordinator. (We highly suggest a video chat if you are able.)

The authors wish to thank Maria Broadstreet, MSN, RN, and Brenna Kouzoukas, MSN, RN, for their assistance and pediatric CVICU insights with this article. 

Sidebar: LVAD Color Codes

Flight nurse educator Allen Wolfe has developed a color-coding system to help EMS providers identify specific LVAD models. Deployed in many areas throughout the country, this program assists EMS services and ED providers by improving information exchange: Callers can simply tell the VAD coordinator the patient has, for instance, a purple VAD, and the make and model are easily identified. Most VAD coordinators know which color corresponds with which type of VAD and can immediately lend guidance. In addition to the color coding, device names are clearly branded on VAD controllers.

• HeartMate 3—green
• HeartMate II—orange
• HeartWare—blue
• Jarvik 2000—purple
• Freedom Driver Total Artificial Heart—pink

Resources 

Dipchand AI, Kirk R, Naftel DC, et al.; Pediatric Heart Transplant Study Investigators. Ventricular Assist Device Support as a Bridge to Transplantation in Pediatric Patients. J Am Coll Cardiol, 2018 Jul 24; 72(4): 402–15.

Guglin M. Approach to Unresponsive Patient with LVAD. VAD Journal, 2018 Jan; 4: 2.

Holleran RS, Wolfe AC, Frakes MA, eds. Patient Transport: Principles and Practice, 5th ed. New York, N.Y.: Elsevier, 2018.

Shin YR, Park Y, Park HK. Pediatric Ventricular Assist Device. Korean Circ J, 2019 Aug; 49(8): 678–90.

Scott DeBoer, RN, MSN, CPEN, CEN, CCRN, CFRN, EMT-P, is a pediatric emergency/transport nurse educator and cofounder of Pedi-Ed-Trics Emergency Solutions.

Allen C. Wolfe, Jr., MSN, APRN, CNS, CCNS, CFRN, CTRN, CMTE, is the senior director of clinical education for Life Link III in Minneapolis. 

Bruce Hoffman, MSN, CFRN, FP-C, CCP-C, NRP, C-NPT,  is a nurse and paramedic specializing in cardiology and emergency/critical care transport. 

Lisa DeBoer, NREMT-P/PI, CET, is a paramedic educator and president of Pedi-Ed-Trics Emergency Medical Solutions. 

Michael Seaver, RN, BA, is a senior healthcare informatics consultant.