1. Member:
1. Ahmad Rafiqan Bin Nayan
2. Muhammad Irfan Bin Alias
3. Mohammad Al-Karim Tayasneh
4. Mohd Izzad Samir Bin Iskandar
2.
3. What is Heart-lung Bypass unit?
External systems that
provide circulation,
oxygenation, and
filtration of the
blood as a temporary
substitute for
circulatory and
pulmonary function.
4. Often used for open-heart surgery, such as
coronary artery bypass grafting and cardiac
valve replacement.
In some cases, used for extracorporeal
membrane oxygenation (ECMO) in patients
with respiratory distress syndrome or with
respiratory insufficiency due to pneumonia,
smoke inhalation, or other causes.
7. During bypass, the patient is heparinized to
prevent blood from clotting within the heart-
lung bypass circuit. (After bypass,
anticoagulation must be reversed by protamine
sulfate)
Heart is infused with a cardioplegic chemical
solution (e.g potassium chloride) to stop its
rhythmic contractions and reduce its metabolic
requirements so as to avoid ischemic damage
to the myocardium.
8. The blood flows to the oxygenator/heat
exchanger for oxygenation, carbon dioxide
removal, temperature regulation, and any
necessary anesthetic exchanges.
Blood that pools in the surgical site is suctioned
and collected in a cardiotomy reservoir, where
it is filtered, defoamed, and either pumped or
drained to the oxygenator.
The oxygenated blood is then returned to the
patient, typically through the aorta, bypassing
the heart and lungs.
11. Roller pumps:
The pumps are designed so that one of the
rollers is always in contact with the pump-head
tubing, compressing it and forcing the blood
forward.
Pump-head occlusion is manually adjusted by
the operator. Some pumps can provide
pulsatile flow.
12. Advantages :
1. Require low volume of blood for priming.
2. The association with minimal biocompatibility
problems (because the tubing is the only
surface that contacts the blood)
3. A low haemolysis rate (possibly due to the lack
of blood backflow or turbulence).
Blood
rupture
13. Disadvantages:
1. Tubing will crack or release plastic fragments
that can become particulate emboli.
2. In the event of a tube blockage, there is a
possibility that the pump will continue to
operate and cause the tubing to rupture.
14. Centrifugal pump:
Uses centrifugal force to move blood through
the system. Spinning cones or rotating fins
create a vortex and force blood centrifugally
through a port in the periphery of the pump
head.
Flow output must be measured using a
noninvasive sensor or a disposable probe
inserted into the arterial line.
15. Advantage :
Reducing the risk of generating particulate
matter in the blood.
Provide protection against over pressurization
of the system in case of tubing occlusion.
Air-lock system- preventing air from being
administered to the patient. If there is air, the
filter will remove the air as the pump will
continue function.
16. Disadvantage :
Non-occlusive: not prevent blood backflow
from the patient if the pump stops, adding to
the risk of air entry into the circulation.
Generally:
Both a backup arterial pump and a connection
to an emergency power system are necessary to
ensure reliable pump operation.
A hand crank for manual pumping is
recommended as an additional backup as it can
provide the high rotational speeds required by
centrifugal pumps.
17.
18. Example :Membrane oxygenator. These devices
usually have an integral heat exchanger to
control the temperature of the blood.
Oxygenator must be primed before use with
lactated Ringer’s solution of
5% dextrose, to remove air pockets and bubbles
from the bypass circuit.
Consist of a gas-permeable membrane
separating a thin layer of blood from the
oxygenating gas.
19. Three major types of membrane oxygenators are
PLATE, COIL, and HOLLOW FIBER.
As a safety precaution, arterial blood is usually
pumped through an in-line arterial filter, which
helps trap particulate matter and gaseous emboli
before they reach the patient. If the filter becomes
clogged, the blood can be diverted through an
arterial-line shunt that has its own filter.
After oxygenation and filtration, the blood is
pumped into the body through a cannula placed in
the ascending aort
or femoral artery at a rate of four to six liters
per minute (L/min), depending on the
patient’s physiologic requirements.
20. To maintain the desired temperature in the
heat exchanger
water mixer regulates delivery of warming and
cooling water
mixer is typically part of the pump console and
includes a thermometer and a backup pressure-relief
valve
A separate electric water heater/cooler can be used
instead of a mixer
21. Thermistor probes are placed at various points
on the patient and in the extracorporeal circuit
Blood gases can be monitored from drawn
samples, by an in-line differential oxygen
monitor
Pressure monitors record left atrial, pulmonary
artery, and systemic arterial pressures
Electronic safety devices have been
incorporated into heart-lung bypass units, with
varying degrees of acceptance
22. Most manufacturers offer ultrasonic bubble
detectors, which use an ultrasonic transducer
and detector to shut down the pumps
automatically when gaseous emboli are
detected in the arterial line.
Level detectors-which alarm when blood falls
below acceptable levels in the oxygenator,
cardiotomy reservoir, or other components.
Some centrifugal pumps include a backflow
alarm to alert the clinician to retrograde blood
flow within the system.
23. Minimally invasive closed-circuit systems (also
called mini-bypass systems) are designed to be
used intermittently during beating-heart
surgery.
Incorporates the pump, filter, and oxygenator
in one housing and is stationed on the main
console.
It small, use shorter tubing and can be placed
closer to the patient as result
patient’s blood spends less time outside the bo
dy
24. less priming is required- this decreased
extracorporeal blood, coupled with less diluted
blood, results in less blood damage.
25. EMBOLISM
IMPROPER OR DEFECTIVE CONNECTION
IN TUBING
FAILURE OF SYSTEM HARDWARE
PROBLEM WITH CERTAIN ANCILLARY
PORTION OF EXTRACORPORCEAL
CIRCUITS
INTERFERENCE BETWEEN HEART LUNG
MACHINE AND BISPECTRAL INDEX(BIS)
MONITOR
