Transcript PowerPoint Presentation: An Overview of Ventricular Assist

Drill of the Month
Developed by Michael Lindsay
An Overview of Ventricular Assist
Devices
&
Pre Hospital Management
Student Objectives
At the conclusion of this Drill Students will
be able to:

Define Heart Failure
 Define Ventricular Assist Device (VAD) and their use in treating
Heart Failure
 Identify types of Ventricular Assist Devices
 Explain the difference between Pulsatile and Nonpulsatile flow
 Identify hemodynamic differences in patients with a VAD
 List VAD related complications
 Demonstrate how to assess a patient with a VAD
 Describe how to treat VAD complications
 Identify VAD resources that can be utilized when caring for
these patients.
Heart Failure
* Heart failure is a condition where the heart
cannot pump enough blood throughout the
body.
* It develops over time as the pumping
action of the heart grows weaker.
* Most cases involve the left side where the
heart cannot pump enough oxygen-rich
blood to the rest of the body.
* With right sided failure, the heart cannot
effectively pump blood to the lungs where
the blood picks up oxygen.
What is a VAD?
A single system device that is surgically attached
to the left ventricle of the heart and to the aorta
for left ventricular support
For Right Ventricular support, the device is
attached to the right atrium and to the
pulmonary artery
Ventricular Assist Device (VAD)

A mechanical pump that is surgically attached to one
of the heart’s ventricles to augment or replace native
ventricular function
 Can be used for the left (L VAD), right (R VAD), or
both ventricles (Bi VAD)
 Are powered by external power sources that connect
to the implanted pump via a percutaneous lead
(driveline) that exits the body on the right abdomen
 Pump output flow can be pulsatile or nonpulsatile
Why Do We Need VADs?

Heart disease is the leading cause of death in the
Western world

~5 million people in the US have congestive heart
failure (CHF)

250,000 are in the most advanced stage of CHF

~500,000 new cases each year

~50,000 deaths each year

only effective treatment for end stage CHF is heart
transplant
Why Do We Need VADs?
 But,
in 2008:

7318 people were waiting for a heart

2210 received one

623 died waiting

~1200-1500 VAD implanted in 2008
Indications for VAD

Bridge to transplant (BTT)
 most common
 allow rehab from severe
CHF while awaiting
donor

Bridge to recovery (BTR)
 unload heart, allow
“reverse remodeling”
 can be short- or longterm
“Destination” therapy (DT)
 permanent device,
instead of transplant
 currently only in
transplant-ineligible
patients
 Bridge to candidacy
(BTC)/
Bridge to decision (BTD)
 when eligibility unclear
at implant
 not true “indication” but
true for many pts

Types of VADs
Pulsatile
and
Non Pulsatile
Pulsatile

Ventricle-like pumping sac device.
 Blood enters via the inflow cannula and fills a flexible
pumping chamber.
 Electric motor or pneumatic (air) pressure collapses the
chamber and forces blood into systemic circulation via the
outflow cannula.

Can be LVAD, RVAD, or BiVAD

First-generation devices (in use since early 1980s)

Patients will have a palpable pulse and a measurable blood
pressure. Both are generated from the VAD output flow.
Pulsatile VAD Key Parameters

Pump Rate:
 How fast the VAD is pumping (filling & emptying)
 Can be set at a fixed rate or can automatically
adjust
 Pulsatile VADs are loud and the rate can be
assessed by listening

Output:
 The amount of blood ejected from the VAD
 Measured is liters per minute
 Is dependent upon preload, afterload, and pump
rate
Non-Pulsatile

Continuous-flow devices

Impeller (spinning turbine-like rotor blade) propels blood continuously
forward into systemic circulation.

Axial flow: blood leaves impeller blades in the same direction as it enters
(think fan or boat motor propeller).

Most implanted devices are LVADs only

Are quite and cannot be heard outside of the patient’s body. Assess VAD
status by auscultation over the apex of the LV. The VAD should have a
continuous, smooth humming sound.

The Patient may have a weak, irregular, or non-palpable pulse

The Patient may have a narrow pulse pressure and may not be
measurable with automated blood pressure monitors. This is due to the
continuous forward outflow from the VAD.

The Mean Arterial Pressure is the key in monitoring hemodynamics.
Ideal range is 65-90 mmHg.
Non Pulsatile VAD Key Parameters

Flow:
 Measured in liters per minute
 Correlates with pump speed (speed=flow,
↓speed=↓flow)
 Dependent on Preload and Afterload

Speed:
 How fast the impeller of the internal pump spins
 Measured in revolutions per minute (rpm)
 Flow speed is set and determined by VAD clinical
team and usually cannot be manipulated outside of
the hospital
Non Pulsatile VAD Key Parameters

Power:
 The amount of power the VAD consumes to
continually run at a set speed
 Sudden or gradual sustained increases in the
power can indicate thrombus inside the VAD

Pulsatility Index (PI):
 A measure of the pressure differential inside the
internal VAD pump during the native heart’s cardiac
cycle
 Varies by patient
 Indicates volume status, right ventricle function, and
native heart contractility
Non Pulsatile VAD Key Parameters

The device parameters are displayed numerically on
the VAD console or Controller

Will vary with each individual patient and VAD device
VAD Parameters
 Parameters
for pulsatile and non pulsatile
devices vary with each device model
 Patients
and their care givers know the
expectable parameter ranges and goals for
their specific device
 Contact
the VAD Coordinator at the implanting
medical center, they will be your best resource
when treating a VAD patient.
Basic VAD Management

ALL VADs are:
 Preload-dependent
 EKG-independent
 Afterload-sensitive
 Anticoagulated
 Prone to:
• infection
• bleeding
• thrombosis/stroke
• mechanical malfunction
 Key differences depend on pulsatile vs. nonpulsatile device
VADs commonly seen in the
community
Thoratec VAD (pVAD/iVAD)

Pneumatic, external(pVAD) or internal (iVAD), pulsatile
pump(s)



right-, left-, or bi-ventricular support
(RVAD/LVAD/BiVAD)
up to ~7.2 lpm flow
Short- to medium-term use (up to ~1-2 years)

bridge to recovery

bridge to transplant

hospital discharge possible
iVAD
pVAD
Thoratec pVAD
HeartMate XVE LVAS


Internally implanted, electric pulsatile pump

left heart support only

up to 10 lpm flow
Medium- to long-term therapy (months to years)

bridge to transplant

destination therapy (only FDA-approved DT device)
HeartMate II LVAS

Internally implanted, axial-flow (non-pulsatile) device

left heart support only

speed: 8000-15000 rpm
• flow: ~3-8 lpm

Medium- to long-term therapy (months to years)

bridge to transplant (FDA-approved)

destination therapy (investigational)
Jarvik 2000 LVAD

Axial-flow (non-pulsatile)
pump


electric, intra-ventricular

left heart support only
Speed: 8000-12000 rpm

flow: ~3-5 lpm

Medium- to long-term therapy
(months to years)

bridge to transplant
(investigational)
Jarvik 2000 LVAD
VAD Issues
Problems/Complications

Major VAD Complications

Bleeding

Thrombosis

Infection
• sepsis is leading cause of death in long-term VAD support

RV dysfunction/failure

Suckdown (low preload causes a nonpulsatle VAD to collapse
the ventricle)

Device failure/malfunction (highly variable by device type)

Hemolysis (the VAD destroys blood cells)
Problems/Complications

Other Common Issues

Arrhythmias
• A patient can be in a lethal arrhythmia and be
asymptomatic. Treat the patient not the monitor.
• Do not cardiovert/ defib. unless the patient is unstable
with the arrhythmia.
• Do not initiate chest compressions unless instructed by a
physician or VAD coordinator. Chest compressions can
disrupt the implanted equipment causing bleeding and
death
• Electrical shock from cardiovert/ defib. will not damage
any of the VAD equipment
Problems/Complications

Other Common Issues

Hypertension
• High afterload can limit VAD flow/ output
• Do not administer antihypertensive medications or
nitrates unless instructed by a physician or VAD
Coordinator

Hypotension/ loss of Preload
• All VADs are preload dependent. A loss or reduction in
preload will compromise VAD function and limit flow/
output
Problems/Complications

Other Common Issues

Depression/ Adjustment Disorders
• Living with a VAD is difficult to management for a lot of
patients.
• A large percentage of patients experience symptoms of
depression

Portability/ Ergonomics
• The external VAD equipment is heavy and cumbersome
limiting a patient’s mobility and greatly impacting their
quality of life.
Problems/Complications
 Bleeding

& Thrombosis
Careful control of anticoagulation is
imperative
• Patients are often on both anticoagulants and
platelet inhibitors
• Device thrombosis


rare in pulsatile devices
typically revealed by increased power and signs and
symptoms of hemolysis
Problems/Complications
 Bleeding




& Thrombosis Tx
Assess for signs and symptoms of bleeding
Neuro Assessment to rule out CVA
Initiate IV therapy and administer fluid slowly
to maintain preload
Device Thrombus is treated with low dose
lytics and/ or increasing anticoagulation
therapy
Problems/Complications
 Infection
*The leading cause of mortality in VAD
patients
*Higher incidence in pulsatile VADs
*The driveline provides direct access into
the body and into the blood stream
*Often recurrent and difficult to treat
Problems/Complications
 Preventing
Infection
* Always observe clean/ sterile
technique when able
* Make sure driveline exit site is
covered with a clean, dry gauze
dressing
Problems/Complications
 Suckdown



LV collapse due to
hypovolemia/hypotension or VAD
overdrive
nonpulsatile devices only
indicators: hypotension, PVCs/VT, low
VAD flows.
Problems/Complications
 Treating



Suckdown
Initiate a peripheral IV and slowly give
volume to increase preload
If able and instructed by the VAD
Coordinator, reduce the speed of the
VAD
Assess for signs and symptoms of
bleeding and sepsis
Problems/Complications
 Device

Failure
This is a true emergency requiring immediate
transport to the implanting VAD center



Most common in pulsatile devices
Patients & caregivers are trained to identify
signs and symptoms of device failure
May require the VAD to be replaced
Problems/Complications
 Hemolysis


Blood cells are destroyed as they travel
through the VAD
More common in non pulsatile devices
Problems/Complications
 Treating



Hemolysis
Initiate a peripheral IV and slowly give
volume
If able and instructed by the VAD
Coordinator, reduce the speed of the VAD
If thrombus is suspected to be causing
hemolysis, administer lytics and
anticoagulants as able/ ordered
Alarms
 All
VAD devices typically have two
distingue alarms to indicate a problem and
it’s severity


Advisory Alarms
Critical/ Hazardous Alarms
Alarms
 Advisory Alarms
are intermittent beeping
sounds that have a corresponding
YELLOW light that illuminates on the
system controller


Not critical but the device requires attention
Likely due to low battery, cable disconnected,
or device not functioning properly.
Alarms
 Hazardous
or Critical alarms are a loud,
continuous, shrill sound that have a
corresponding RED light that illuminates on the
system controller



Indicating the device needs immediate attention
Often because the pump has stopped or a problem
is detected with the system controller
Most likely intervention required is to change out
the system controller
Field Management
 All
VADs are dependant on adequate
preload in order to maintain proper
functioning
 Volume resuscitation in an unstable VAD
patient is the first line of therapy before
vasopressors but be cautious with fluid as
to not over load the right ventricle in L
VADs only.
Field Management
 Nitrates
can be detrimental to a VAD
patient because of the reduction in preload


Results in decreased pump efficiency
Consult with medical control before
administering nitrates per protocol
Field Management
 Initiate
IV therapy with all VAD patients if
possible

Use aseptic technique due to the patient’s
increased risks of infection
Field Management
 VAD
patients are susceptible to other
injuries unrelated to the VAD
 Contact the VAD Coordinator, they are
your most valuable resource when
encountering these patients
 Consult with medical control about
transport
Patient Transport





This is emergency, resource and protocol driven
decision making
VAD patients require unique care that not all medical
centers are equipped to handle. Transport to the
implanting center when able or the closest VAD center
Make sure when transporting to bring all VAD related
equipment
Secure VAD batteries and the controller to prevent
dropping or damage
Make sure to keep all cables tangle and kink free
Preplanning
 Medical

Inquire ahead of time the level of knowledge/
comfort with your medical directors regarding
the management of VAD patient
 Know


Control
Transport Options
Air vs. Ground
Know your tertiary facilities and their ability to
management VAD patients
Remember…
 EMS
can walk into just about any situation
 Depending on the individuals- the family may
not be able to handle the emergency
 Listen to the family members that can handle
the emergency and “assist” them with whatever
they need
 The only resources/ tools you can truly rely on
are the ones you bring to the call
 Follow-up and educate yourself to new
technologies that keep entering into the industry
Remember…
 Ask
for the contact number for the managing
center’s VAD Coordinator as soon as you
arrive, this should be on the person or close by.
This is the coordinator they work very closely
with and will be your best resource
 Family, friends, co-workers- listen to them for
direction, they should be educated/ trained to
assist with most VAD related complications
 911 activation may not be for a VAD related
emergency
Remember…

Emergency bag containing back-up VAD supplies
needs to stay with the patient at all times. Should
contain extra batteries and the spare system controller
 Ask the family for any trouble shooting guidelines that
maybe available. This often includes various alarms
and interventions
 Remember that the family/ friends are not emergency
responders or maybe too upset to assist you
 If a VAD patient calls 911 it will not be for something
simple like a battery change. VAD related
emergencies are serious life threatening events
For additional resources materials
and information please visit:
 www.thoratec.com
 www.jarvikheart.com
 www.umm.edu/heart/index.htm
Thank You!