Transcript Limitations of IABP in Pediatric Patients

Ventricular Assist Device
Seoul National University Hospital
Department of Thoracic & Cardiovascular Surgery
Acute Heart Failure in Child
Etiology
• Previous well child with structurally normal
heart, most commonly, secondary to acute or
fulminant myocarditis (lymphocytic myocarditis)
or cardiomyopathy
• Childrens, either in the early postoperative, or
longstanding myocardial dysfunction with
congenital heart disease
Acute Heart Failure in child
Non-pharmachologic treatment
• Balance between myocardial oxygen demand
and delivery
• Temperature control
• Mechanical circulatory support
• Intraaortic balloon pump
• Cardiopulmonary interaction; role of
mechanical ventilation
Mechanical Support
Indications
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Acute myocarditis
Low cardiac output state after cardiac surgery
A bridge to transplantation
Overwhelming systemic sepsis with circulatory failure
Severe pulmonary hypertension
Emergency management of intractable arrhythmia
with severely compromised myocardial perfusion,
subendocardial ischemia, and acute ventricular
dysfunction
Ventricular Assist Device
Ideal requirements
1. Durable
2. Biocompatible
3. Nonthrombogenic
4. Resistant to infection
5. Reasonably priced
6. Available numerous size
Ventricular Assist Device
Recent available specification
• Centrifugal pump
• Implantable pneumatic pulsatile Heartmate(Thermo
Cardiosystem)
• Paracorporeal ABIOMED BVS 5000 pump(ABIOMED)
• Paracorporeal pneumatic pulsatile Thoratec
VAD(Thoratec Laboratories)
• Paracorporeal pulsatile pediatric VAD System
including Berlin Heart VAD(Mediport Kardiotechnik)
& MEDOS HIA-VAD System(BYTEC GmbH)
• Jarvik 2000 System( Jarvik Research)
Intraaortic Balloon Pump
Calculation of IABP volume
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CO = HR x SV
SV = CO / HR
CI = CO / BSA
CO = CI x BSA
SV = ( CI x BSA ) / HR
IABP volume = 0.5 x SV = 0.5 x (CI x BSA)/HR
Assume CI = 2.0L/min/square M
Then, IABP volume = ( 1000 x BSA ) / HR
Mechanical Circulatory Support
 ECMO
1) ACT time 180-220 sec( around 200 )
2) Antifibrinolytic therapy
Initiation ; 100mg/kg
Maintain ; 30mg/kg
3) After congenital heart surgery with hypoxia,
pulmonary hypertension, biventricular failure
 VAD
1) 50ml Biopump less than 10kg
2) 80ml Biopump above 10kg
3) ACT 150-180 seconds ( around 150 )
4) Simple, less anticoagulative, less blood trauma
5) Platelets above 100,000, normal PT,
fibrinogen above 200mg%
Extracorporeral Membrane Oxygenation
Advantages & disadvantages
• Possibility of providing total cardiopulmonary support
and allowing for cardiac and pulmonary healing, but
needs for higher level of anticoagulation, leads to
bleeding, increased blood loss, blood product
requirement, multiple exploration, and potential
infection
Indications
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Neonatal respiratory failure
Pediatric respiratory failure
Neonatal and pediatric cardiac failure
Adult cardiorespiratory failure
Mechanical Circulatory Support
Technical principles
• In children, the most common form of VAD involves
use of centrifugal pump
• Atrial pressure lines are neccessory to monitor for
adequate decompression and kept as close to zero as
possible to ensure ventricular decompression
• All inotropes should be withheld if possible during the
recovery period
• Serial stress echocardiography should be performed
every 1-3 days to document progression of recovery
• Decannulation should be performed by gradually
weaning VAD support and be a team approach with
preparation of volume & catecholamine infusion ready.
Mechanical Assisted Circulation
Control of blood activation
• Surface modifications
• Inhibition of initial events
Platelet anesthesia
Contact phase inhibition
Complement inhibition
Monocyte inhibition
• End-point inhibition
Antifibrinolytic drugs
Modulation of neutrophil-mediated injury
Surface Modifications
Methods of modification
• Physical modification
• Chemical modification by grafting
a hydrophilic component
• Surface modification by inclusion
of bioactive components
• Biomembrane mimicry
• Cellular seeding and lining
Mechanical Circulatory Support
Complications
• Hemorrhage
1. Local bleeding
2. Major intracranial hemorrhage
3. Coagulopathy and clot formation
• Sepsis
• Multisystem organ failure
• Failure of myocardial recovery
• Mortality
IABP in Pediatric Patients
 Limitations
1. Inadequate hemodynamics due to increased
aortic elasticity
2. Rapid heart rate with small stroke volume
3. Technical difficulties related to insertion
4. Vascular occlusion of renal, mesenteric artery
& limb ischemia
5. Limited applications d/t small balloon
VAD for Pediatric Patients
Limitations of development
1 Size constraints
2 Differences in pathophysiology of failure
1) Right ventricular failure
2) Biventricular failure
3) Pulmonary failure
Ventricular Assist Devices
Advantages
• Providing good oxygen delivery to the tissue
• Unloading the supported ventricle to allow time for
ventricular healing
• Lower levels of anticoagulation than the ECMO
Disadvantages
• Bleeding complication
• Potential pulmonary dysfunction necessitating
conversion to ECMO
• Potential for infection
• Require a median sternotomy for direct access
Left Ventricular Assist Device
• The LVAD assists left ventricular function by pumping
blood from left atrium to aorta
Right Ventricular Assist Device
• The RVAD assists isolated right ventricular dysfunction by
pumping blood from right atrium to pulmonary artery
Berlin Heart VAD
• Berlin Heart VAD is a paracorporeal air-driven pulsatile VAD
Jarvik 2000 System
• Javik 2000 is an intraventricular axial flow impeller pump requiring
percutaneous electric power of possible implanted battery power
Biventricular Assist Device
• Thoratec. BIVAD
Extracorporeral Membrane Oxygenation
Cardiopulmonary Support System
Cardiopulmonary Support System
• Cardiopulmonary Support System are actually
modified ECMO circuits, have been used for rapid
resuscitation during acute cardiac and pulmonary
failure, designed as highly mobile units that offer the
high-risk cardiac patient a safety net especially in the
interventional cardiac catheterization.
• There are two potential disadvantages with this system;
limited oxygenator durability and an increased
potential for air embolism.
• Advantages over conventional ECMO includes rapid
set-up time with a bloodless prime, decreased
postoperative blood loss, and simplified transport.