CARDIAC ASSIST

DEVICES
 -Dhinakaran.S B.E ECE
 CONTENT
Open And
What is cardiac assist
devices and How It Is Closed Chest
Assisted Through
Respiration
Types

INTRO EXPLORE Types VADS

What Is RVADS & LVADS

Auxiliary (artificial pumps)
Ventricle
 What is cardiac assist devices?

 A medical device designed to support and augment(increase)

the function of the heart in individuals with severe heart failure
or other cardiac conditions is called CAD.
 A cardiac assist device (CAD), also known as a ventricular
assist device (VAD).
 These devices can be used as short-term therapy, bridge to
transplantation, and as permanent cardiac support
 How it is Assisted Through Respiration?

 Assisted through respiration is life-support intervention

where a person's breathing augmented using mechanical
devices or techniques.
 This assistance can be provided when a person is unable
to breathe adequately on their own. Often due to
respiratory failure.
 There are several ways respiration can be
assisted:
 Mechanical Ventilation
 Bilevel Positive Airway Pressure (BIPAP) or Continuous Positive Airway
Pressure (CPAP)
 Oxygen Therapy
 Bag-Valve-Mask (BVM) Resuscitation
 Intubation and Endotracheal Tubes
 Tracheostomy
 Non-Invasive Ventilation
 EXPLANATION:

 Mechanical Ventilation:This involves using a ventilator, a machine that delivers air

with oxygen into the lungs and removes carbon dioxide. It's often used in critical
care settings, such as intensive care units (ICUs), to support patients with severe
respiratory issues.
 Bilevel Positive Airway Pressure (BIPAP) or Continuous Positive Airway
Pressure (CPAP):These devices deliver a constant flow of air into the airways to
help keep them open. BiPAP provides different air pressures during inhalation and
exhalation, while CPAP delivers a continuous pressure.
 Oxygen Therapy: This involves delivering supplemental oxygen to a person who
is not receiving enough oxygen on their own. It can be done through a nasal
cannula, oxygen mask or other devices.
 Bag-Valve-Mask (BVM) Resuscitation: This technique involves manually squeezing
a bag attached to a mask over a person's face to provide positive pressure ventilation.
It's often used during CPR or in emergency situations.
 Intubation and Endotracheal Tubes: in some cases, a tube may be inserted into a
person's windpipe (trachea) to maintain an open airway and provide ventilation
 Tracheostomy: A surgical procedure where a hole is made in the front of the neck and
a tube is inserted directly into the trachea. This is done when a person needs long-term
assistance with breathing
 Non-Invasive Ventilation: This includes methods like using a mask over the nose
and/or mouth to provide positive pressure ventilation, as seen in BiPAP or CPAP
  What Is Auxiliary Ventricle?
 An auxiliary ventricle is a mechanical pump that is used to help the heart pump
blood. It is a type of ventricular assist device (VAD).
 Auxiliary ventricles are typically used in patients with severe heart failure who are
not responding to other treatments. They can be used as a bridge to heart
transplantation or as a permanent treatment.
 Auxiliary ventricles are implanted in the chest and connected to the heart with
tubes. The pumps are powered by a battery pack that is worn on a belt or in a
backpack.
 Auxiliary ventricles can improve the quality of life for patients with severe heart
failure. They can help patients to breathe easier, have more energy, and reduce
their risk of death.
 Schematic representation:
 Structure:
 An artificial auxiliary ventricle is provided having a generally spherical shape and an
internal configuration to direct or regulate the flow of blood.
 The unit is implanted in the ascending aorta during short-term inflow and outflow
occulsion(block) of the heart after which the circulation is re-established and the
anastomosis completed, or by direct and through side anastomosis without interrupting
the circulation.
 The device is driven by compressed air from an outside tank via an air tube and is
controlled by a solenoid valve which is triggered by the ECG or the left ventricular
pressure curve.
THE RISKS OF AUXILIARY VENTRICLES
INCLUDE:

 Infection: The pump can introduce bacteria into the bloodstream,

leading to infection.
 Blood clots: Blood clots can form in the pump or in the blood
vessels leading to the pump. These clots can travel to the brain and
cause a stroke.
 Device malfunction: The pump can malfunction, which can stop it
from working properly.
TYPES OF CADS:
OPEN CHEST TYPES
 CLOSED CHEST TYPES
 OPEN CHEST TYPES:

 Open chest CADs are surgically implanted inside the chest.

 They are typically used for people who are in end-stage heart failure
and need a more permanent solution.
 There are two main types of open chest CADS:
⚫ Ventricular assist devices (VADs): These
devices help the left or right ventricle of the heart pump blood.
⚫Total artificial hearts (TAHS): These
devices replace the entire heart.
 CLOSED CHEST TYPES

 Closed chest CADs are placed on the outside of the chest.

 They are typically used for people who are waiting for a heart transplant or who need
temporary support while their heart recovers from an injury or illness.
 There are two main types of closed chest CADs:
 ⚫ Intra-aortic balloon pump (ABP): This device is
inserted into the aorta and inflates to help increase blood flow to the heart.
 ⚫ External counter pulsation (ECP): This device
uses cuffs that are placed on the legs to inflate and deflate in a synchronized pattern
to help increase blood flow to the heart.
 Differences:

FEATURES OPEN CHEST CLOSED CHEST

TYPES TYPES

Location Inside the chest Outside the chest

Duration of use Permanent or long-term Temporary

Risks Surgery, infection, blood Less invasive, fewer risks

clots

Recovery time Longer Shorter

 LEFT AND RIGHT
VENTRICULAR DEVICES
 What is a left ventricular assist
device?
 A left ventricular assist device (LVAD) is a mechanical pump that providers implant in
people who have heart failure.

 The device helps the lower left chamber (left ventricle) of your heart pump blood out of
the ventricle to your aorta and the rest of your body. Because it helps your left ventricle,
it's a left ventricular assist device.

 This is an important job because your aorta sends oxygen-rich blood to your whole
body. You can't live without a steady supply of oxygen to your cells and tissues.
 How does a left ventricular assist
device work?
 A left ventricular assist device works by pumping blood from your left ventricle to
your aorta.

 Your aorta is the large artery that takes blood from your heart to the rest of your
body. A surgeon implants the left ventricular assist device's pump unit at the
bottom of your heart inside your chest.

 The device receives blood and sends it through a tube to your aorta.
 Condition for LVADS call:
 What are the parts of a left ventricular
assist device?
 Pump: Attaches to a driveline (cable) and control system (controller).

 Driveline:Passes from the device through the skin on your belly (abdomen
controller (a small computer) on the outside of your body

 Controller: Runs the pump. Messages and alarms from the controller help you) to
the operate the system.

 Power supply: Keeps the LVAD running with rechargeable batteries or a cord that
plugs into an electrical outlet. Batteries can provide up to 14 hours of power,
depending on the device. When the batteries are low on power, you need to
replace them.
 What does a left ventricular assist
device manage
 A left ventricular assist device is for people with end-stage heart failure. It's a bridge
to transplant for people waiting for a heart transplant. It can also help people who
aren't candidates for a heart transplant.

 Healthcare providers call that destination therapy. Bridge to transplant (BTT) While
you wait for a heart transplant, your medical condition may continue to get worse.

 This may lead to hospital admission, increased symptoms and damage to other
organs such as your kidneys, liver and lungs.
Bridge to transplant
 Bridge to transplant (BTT) helps you survive until you can receive a donor's heart. The LVAD assists your
heart and allows you to have a better quality of life and fewer symptoms. A surgeon removes the device at
the time of your transplant The amount of time you receive support from an LVAD until heart
transplantation varies and depends on your medical condition, blood type and body size.

Destination therapy (DT)

 Destination therapy (DT) is for people with heart failure who aren't candidates for heart transplant
surgery. Healthcare providers consider this only for people after they've tried everything else (like
medications, lifestyle changes and heart procedures)A left ventricular assist device supports your heart's
function and improves your quality of life for the rest of your life. Your provider will determine if a left
ventricular assist device is an appropriate treatment option for you, based on your medical condition,
symptoms, body size and presence of other medical conditions
RIGHT AND LEFT VENTRICULAR
BYPASS PUMP
 RIGHT AND LEFT VENTRICULAR
BYPASS PUMP

 Function of Left Ventricular Bypass Pump The goal in developing a left ventricular bypass
pump is to relieve strain on the failing heart during the critical recuperative period after
cardiac damage.

 Ineffective emptying of a failing left ventricle during systole decreases cardiac output and
lowers systemic pressure. The increase in left ventricular end-diastolic pressure inhibits
filling from the left atrium, and the resulting rise in left atrial pressure increases pulmonary
venous pressure and causes pulmonary congestion.
 RIGHT AND LEFT VENTRICULAR
BYPASS PUMP
 The complex metabolic changes consequent to these hemodynamic disturbances, if an
attended, produce a vicious cycle that leads to rapid deterioration of the patient's condition .

 The reduction in arterial oxygen tension caused by the pulmonary congestion further inhibits
tissue perfusion, which has already been impaired by the low cardiac output.

 The resulting severe metabolic acidosis further restricts cardiac function and, if this series of
events is not reversed, vasopressor resistant hypotension, hypoxemia, arrhythmia and death
ensue. Use of the left ventricular bypass pump interrupts.
 This cycle by immediately lowering left
atrial pressure and, therefore, left
ventricular end- diastolic pressure Strain
on the failing left ventricular myocardium
is reduced, and pulmonary congestion is
relieved, with improvement in arterial
oxygen tension. The resultant prompt
increase in cardiac output and in coronary
flow of well-oxygenated blood to the
myocardium enhances recuperability of
the myocardium and left ventricular
function.
 Description of the Pump
 The left ventricular bypass pump is a gas-energized synchronized pump of hemispherical
design made of Dacron-reinforced Silastic, with a molded diaphragm separating the gas
chamber from the blood chamber.

 Pressurized CO2. pulsed into the gas chamber collapses the central lumen or blood chamber
and thereby empties it. A Teflon bellows driven by an electric motor constitutes the external
energizing and controlling system.

 The pump may be controlled manually or by an electrocardiographic triggering mechanism.

The speed of the motor is controlled by phase-variable firing of silicon-controlled rectifiers,
and a dynamic braking circuit brings the motor to a complete stop at the end of each stroke.
 Description of the Pump
 Synchronization is maintained by initiation of a stroke from each electrocardiographic signal, every other signal or every
third signal. This override circuit also ensures continuous operation, not necessarily synchronized, in case the
electrocardiographic rate should rise sharply or be interrupted.

 Stroke and volume may be regulated to determine output. The transistorized control system has a minimum of switch
and relay contacts. An independent power supply operates the system without synchronization, and the entire system can
become a portable unit for as long as 1 hour by use of a battery-powered converter. The pump lies completely outside
the body.

 One connecting tube is inserted, through an intercostal incision, into the left atrium and the other, through a small
incision, into a systemic artery, such as the right axillary artery, which is readily accessible and requires insertion of only
I tube into the chest.

 When the pump is no longer needed, its removal is relatively simple and consists essentially in dividing the connecting
tubes just beneath the skin, under local anaesthesia, and oversewing the proximal ends and then suture-closing the
subcutaneous tissue and skin overlying the closed ends of the tubes.
 Cardiac Assist Devices To Aid The
Failing Heart
 Different types of cardiac assist devices have been developed to aid the failing heart.

 These devices can be divided into roller pumps, balloon pumps, ventricular assist devices, and

total artificial hearts.

 Roller pumps provide temporary support during or immediately following cardiac surgery.

 Balloon pumps aid the heart during cardiopulmonary bypass and cardiogenic shock.

 Ventricular assist devices assist the function of either the left or right ventricle. Total artificial

hearts entirely replace the human heart

 Roller pumps
 Roller pumps were the first generation of cardiac assist devices. These devices are designed to
allow the natural heart to rest and recuperate after the surgical procedures have been completed.
 Roller pumps were first used in humans in 1953. These pumps are non pulsatile and are used during
cardiopulmonary bypass (CPB). They remain an integral part of most modern extracorporeal
membrane oxygenators (ECMO), supporting patients for an average of 10 days.
 During open heart surgery, blood is routed extracorporeally (outside the body) through arterial and
venous cannulation via clastic tubing to membranes that facilitate oxygen and carbon dioxide
exchange with the blood.
 Roller pumps used in CPB and ECMO have resulted in extremely high levels of damage to red blood
cells (hemolysis) and other blood components with increasing damage with extended support
time.
 Patients are then required to take high dosage levels of anticoagulants that may lead to excessive
bleeding Additional complications include blood cavitation due to tubing fatigue resulting in the
tubing becoming less compliant. Because of these complications, roller pumps are typically limited
to pediatric patients, and those adult patients who do not require large flow rates.
 Roller pumps
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