EMS A to Z: Mechanical Circulatory Support Devices

Show Notes:

From your hosts, Dr. Josh Gaither, Dr. Amber Rice, and Dr. Rachel Munn

 

There are two types of mechanical circulatory support devices: Left Ventricular Assist Devices (LVAD) and Total Artificial Heart (TAH). 

 

Left Ventricular Assist Device:

An LVAD is a Mechanical Circulatory Support (MCS) device designed to restore blood flow and improve survival, functional status, and quality of life for those suffering from advanced heart failure.

The device is implanted in parallel with the heart, taking over a majority of its circulatory function.

An LVAD is often implanted as a temporary treatment, but is sometimes used as a permanent solution to very low cardiac output.

 

What are the reasons for VAD implantation? 

Bridge to Transplant

The patient must meet criteria to be listed for a heart transplant

Destination Therapy

The patient does not qualify for a heart transplant but meets criteria for Destination Therapy

The patient lives the rest of their life with an VAD

Bridge to Recovery

VAD for a few days or weeks, provides temporary supportto a patient expected to recover native heart function

 

What are the special considerations for LVAD patients? 

Routine assessments such as blood pressure, pulses, and pulse-oximetry may not be unattainable  

Chest compressions are usuallynot indicated 

The patients carry external equipment: a controller and power sources that operate the implanted pump though a single driveline

 

How do you assess patients with LVADS? 

Attempt to auscultate over the apex of the heart for a “whirling” or “smooth, humming” sound indicating that the VAD is working 

A cable exits the abdominal wall that connects the device to power and the control unit

Many VAD patients also have an implanted cardiac defibrillator

Blood Pressure (BP) - BP taken with a manual cuff;  Automatic BP readings are considered unreliable

Pulse - A palpable pulse is variable and clinically insignificant in VAD patients

Pulse Oximetry- Can be unreliable

Look for physical s/s of ↓ oxygenation

EKG is typically unaffected

 

What types of problems are LVAD patients at risk for? 

Bleeding complications due to blood thinner use

Arrhythmias

VAD flows may be affected

Infection (as with any implanted device)

 

How do you treat arrhythmias in LVAD patients? 

Many VAD patients have an ICD / Pacemaker

Persistent arrhythmias are treated aftercontacting the VAD coordinator 

Okay to defibrillate & cardiovert VAD patients per ACLS protocol

Okay to administer anti-arrhythmic medications per ACLS protocol

 

What are the differences between LVADs and Total artificial hearts? 

An ECG is meaningless since there is no heart

Pulse oximetry is accurate

A regular BP measurement may be obtained

Chest compressions are not performed

Cardioversion or defibrillation are not performed