CPB Hardware and Primes. A comprehensive presentation

1. CARDIOPULMONARY BYPASS HARDWARE
AND
PRIMES

3. “However, we had begun to suspect massive physiologic disturbances evoked by total body
perfusion and open cardiotomy about which we knew very little and that by temporarily
instituting a ‘‘placental’’ circulation we might minimize or even correct those to permit
successful surgeries that would have otherwise been impossible”
Herbert Warden
Clarence Walton Lillehei Morley Cohen

4. CARDIOPULMONARY
BYPASS EQUIPMENTS

5.  CARDIOPULMONARY BYPASS CIRCUIT
 PUMPS
 ROLLER
 CENTRIFUGAL
 PULSATILE
 NONOCCLUSIVE ROLLER/PRESSURE REGULATED PUMPS
 EXTRACORPOREAL CIRCUITRY
 BLOOD GAS EXCHANGE DEVICES
 HEAT EXCHANGERS
 CANNULA AND TUBING
 FILTERS AND BUBBLE TRAPS
 CARDIOPLEGIA DELIVERY SYSTEMS
 DISPOSABLE CARDIOPLEGIA CIRCUITS
 CARDIOPLEGIC DELIVERY CATHETERS
 ANTEGRADE AORTIC ROOT ROOT CARDIOPLEGIA
 RETROGRADE CORONARY SINUS CARDIOPLEGIA

6. CARDIOPULMONARY
BYPASS CIRCUIT

7. CARDIOPULMONARY BYPASS CIRCUIT
• Oxygenation and elimination of CO2.
• Circulation of blood.
• Systemic cooling and re-warming.
• Diversion of blood from the heart.

8. BASIC SCHEMATIC

10. CARDIOPULMONARY BYPASS CIRCUIT

11. CARDIOPULMONARY
BYPASS PUMPS

12. Flow Rate 7 L/ Min Pressure 500 mm Hg
Non Damaging
No Turbulence
Disposable
Exact Calibration
Manually Operable
BLOOD PUMPS

13. 4 Types
•Roller Pumps
•Centrifugal Pumps
•Pulsatile Pumps
•Non Occlusive Roller Pump
BLOOD PUMPS

14. Most common
1855 patented by Porter and Bradley
1934 De Bakey modified
1959 Melrose grooved backplate.
ROLLER PUMPS
Classified according to number of rollers
A. Single –More pulsatility.
B. Double –Relatively nonpulsatile flow
C. Multiple – causes more haemolysis.

15. • Positive Displacement Pump
• Length of tubing inside curved raceway
• Predictable pump flow
• Preload/ Afterload independent
• Simple
• Setting Occlusion
ROLLER PUMPS

16. ROLLER PUMPS – OCCLUSION.

17. • Malocclusion
• Miscalibration
• Tubing Fracture
• Runaway pump
• Spallation
• Air Pumping
• Cavitation
ROLLER PUMPS – POTENTIAL ISSUES

18. ROLLER PUMP: POSITIVE DISPLACEMENT
PUMP
CENTRIFUGAL PUMP: KINETIC PUMP
Advantages • Reusable pump with disposable parts
• Ease of sterilization
• Simple flow rate determination: (rpm x sv)
• Variable SV for different sized patients
• No possibility of disruption from excessive line
pressure buildup
• Decreased blood trauma
• Less risk of massive air emboli
• Less cavitation
• Elimination of tubing wear or spallation
Disadvantages • Blood trauma
• Possibility of circuit disruption from excessive
line pressure
• Particulate microemboli from tubing spallation
• Possibility of massive air emboli
• Occlusion variability affecting flow rate and
blood trauma
• Contraindicated for long term use because of
tubing wear and blood trauma
• Different operator technique for initiation
• Flowmeter is necessary
• Retrograde flow when pump slows or stops
• More expensive non-reusable

19. CENTRIFUGAL PUMPS
Since 1976
Impeller with Vanes/ Cones
Magnetically coupled another magnet in pump head
Non Occlusive
Pre & After load Dependent

20. CENTRIFUGAL PUMPS
Less blood trauma
Does not over pressurize & disrupt
No tubing wear
No spallation
No cavitation
Decreased risk of air embolism

21. CENTRIFUGAL PUMPS – ISSUES
Lacks versatility in placement
No vent / suction
Adds to complexity
Adds to cost
Non Pulsatile
Retrograde flow

22. Pump chamber
Polyurethane bag
Wrapped around rollers
No negative pressure generated
No retrograde filling
Does not damage blood elements
PERISTALTIC PUMP

23. NONOCCLUSIVE ROLLER PUMP
• Metaplus pump (Baxter Healthcare):
• No Negative pressure
• No over pressure.
• No retrograde flow.
• Priming Volume – 120 mL.

24. EXTRACORPOREAL
CIRCUITRY
BLOOD GAS EXCHANGE DEVICES
HEAT EXCHANGERS
CANNULA AND TUBING

25. OXYGENATORS
The ideal oxygenator:
1. Excellent gas exchange.
2. Minimum trauma to the blood.
3. Smaller priming volume.
4. Safety - the device must be easily assembled, primed and operated
5. Minimum pressure drop.
6. Minimal faliure incidents and easy to replace during CPB
Types of oxygenators:
• Disk & film oxygenator
• Bubble oxygenator
• Membrane oxygenator

27. BUBBLE OXYGENATOR
• Blood drains into chamber
• Oxygen diffuses through diffusion plate
• Simple
• Easy to prime
• Inexpensive
• RISKS
• Gas embolism
• > 2 hours protein denaturation
• Platelet, complement activation.

28. MEMBRANE OXYGENATOR
• Characteristics:
• Gas exchange across a thin membrane
• No direct contact with blood - more physiologic
• Minimal blood damage
• Two types:
• Solid type (Silicone)
• Microporous type (polypropylene)
• 0.3-0.8-um pores
• Popular design = hollow fiber membrane (120-200 um)
• Advantages
Safer; Less particulate and gaseous emboli; Less reactive
• Problems
Plasma leakage and membrane wets at use of period > 6 hours

29. Membrane material are organized
into three types of configuration:-
1. Scrolled envelope,
2. Parallel plate and
3. Hollow fiber.
Currently most commonly used
oxygenators are membrane
oxygenators with polypropylene
hollow fiber structure

30. GAS BLENDER
Simple oxygen blender integrated with flow meter for CPB
A standard O2 blender
Can supply 21-100% FiO2
With gas flow@ 100 ml to 10 Ltrs.
It has a high pressure relief valve for safety purpose .

31. RESERVOIR
HARD SHELL
Open to atmosphere
• Easier to measure volume
• Handling venous air more effectively
• Larger capacity
• Easier to prime
• Permits vacuum assisted venous
drainage

32. RESERVOIR
SOFT SHELL
Collapses on Itself.
Eliminates blood gas interface and reduces
risk of massive air embolism.
Cardiotomy sucker is not permitted.

33. HEAT EXCHANGERS
• Function in combination with an external
heater-cooler (TCM).
• Warms and Cools patient.
• Proximal to Oxygenator.
• Heat exchange is also improved by
allowing the blood and water to flow in
opposite directions

34. TCM – TEMPERATURE CONTROL MONITOR
Now a days standard TCM consist of two tanks.
Large and small tank
• Three outlets of water-
to Heat exchanger, to Blanket and to BCD system.
A control panel with digital monitor
Capacity: large tank 34 ltrs, small tank 4.5 ltrs
Temperature : Range 0 to 42°c

35. BLOOD CARDIOPLEGIA DELIVERY SYSTEM
• Used for the delivery of cardioplegia.
• Inbuilt heat exchanger within the device.
• BCD facilitates the delivery of cardioplegia along
with blood in the ratio of 4:1 for St. Thomas
solution and 1:4 for del Nido solution by some
modification in the circiut.
• The temperature of the BCD is controlled through
the TCM.
• Priming volume of this device is approx 60 ml.

36. CANNULA

37. ARTERIAL CANNULA
• Narrowest part of circuit
• High flow jet
• Pressure gradient > 100 mm Hg hemolysis
• Choose smallest canula that will provide calculated
flow rate with a gradient < 100 mm Hg
• COANDĂ EFFECT
• Tendency of a jet stream to adhere itself to a curved
surface due to areas of low pressure. Preferential flow.
• Carotid hypoperfusion

38. DOUBLE LUMEN ARTERIAL CANNULA

39. VENOUS CANNULATION AND DRAINAGE
CANNULA chosen by Size and AGE & WEIGHT
1 STAGE 10 - 46 F
2 STAGE 36- 51 F
Flow 1/3 SVC & 2/3 IVC
CANNULATION
Bicaval Cavo atrial
Single Atrial Peripheral

40. PERFUSION CANNULA CHART

41. VENOUS DRAINAGE
Gravity Siphon
Assisted
Vacuum Assisted (VAVD)
Regulated vacuum to closed hard shell reservoir
Kinetic Assisted (KAVD)
Centrifugal pump in venous line
Roller pump
Between cannula and reservoir

42. ADVANTAGES OF ASSISTED VENOUS DRAINAGE
• Improved venous return.
• Lowers the priming volume.
• Alternative venous cannulation sites
• Almost impossible to have an air-lock in the venous line
• Improved drainage in special procedures. [ Heart port, modified access cases ]

43. VAVD

44. CORONARY PERFUSION CANNULAE
• Self-inflating balloon cannulae
and cone tip cannulae
• Balloon inflating is automatic and
continuous and results from the
infusion of cardioplegic solution
• Less traumatic

45. RETROGRADE CARDIOPLEGIA CANNULA
• A soft flexible PVC tip
• Stainless steel trocar needle and features a
security system: on removal, the steel tip of
trocar retracts completely into a protective
sheath thus preventing injury.
• Luer-lock connectors for quick connection
• Automatically inflating balloon by the flow of
cardioplegic solution to seal and secure the
cannula tip in position within the coronary
sinus.
• The pressure at the cannula tip can be
monitored using the measuring lumen.

46. TUBING
• Medical grade Polyvinyl Chloride (PVC) with tygon to make it durable.
•Transparent
•Resilient
•Flexible
•Non-kinking
•Hardness
•Tough
•Inert
•Smooth
•Non-wettable
•Heat Tolerance
•Blood compatibility

47. BIO MATERIAL TUBING.
Binding heparin or other surface modifying agents into inner surface of the tubing to improve biocompatibility.
Examples
1. Biomembrane mimicry – Tubing are coated with a derivative of phosphorylcholine (Memys, Sorin)
2. Heparin coated circuits
Heparin bound to tubing is slowly released into circulation (Duroflo ll, Baxter)
Heparin is permanently bound covalently to biomaterial surface (Carmeda,Trillium, Medtronic)
Hybrid surface-combination of heparin releasing and heparin immobilized (Bioline, Jostra).
3. Surface modified additives -Terumo Corporation has developed CPB circuits coated with poly 2-methoxy ethylacrylate
which has hydrophobic properties and little tendency to react with blood products.
ADVANTAGES
Potent antithrombotic behavior.
Decreased thrombogenecity. (No evidence)
However, inflammation related to complement activation is decreased.

48. CONNECTORS
• Connectors are made of poly carbonate; used to connect
-tubing to tubing.
-tubing to cannulae in different parts of the circuit.
• Different size and shape are available

49. SAFETY DEVICES
• Power failure alarm
• Bubble detector
• Level sensor
• Anaesthetic gas-scavenging apparatus
• Out of range temperature alarm on the heater–cooler unit.

50. LEVEL SENSOR AND BUBBLE DETECTOR

51. FILTERS
• Filters are used in numerous locations in the CPB
circuit.
1.Arterial line filter:-
Characteristics of arterial line filter-
Very low resistance.
Easy to de-air.
Removes both particulate and gaseous emboli.
Produces minimal blood trauma.
Minimal holdup volume.

52. • 2.Cardiotomy filters- microemboli- related to
blood trauma and platelet activation in the
pericardium- fat particles, and bone wax. pore
size generally 20-µm.
• 3.Prebypass filter- Extracorporeal circuit contains
particles of all sizes, like glass plastisizers, bits of
tubing from spallation and even endotoxin.
It has pore size 0.2-5 µm.

53. • 4. Transfusion filters- used for filtration of
stored blood.
Screen filter, depth filter or combination
Pore size- ~40 µm.
• 5. Gas filter- Bacteria or debris which are
present in medical O2 or CO2 or Nitrous
Oxide.
Pore size- 0.2 µm.

54. Cardioplegic filter- Particulate contaminants have been demonstrated in crystalloid
cardioplegic solutions. Pore size of 0.2- 5 µm. For blood cardioplegia 20-40 µm.

55. ULTRAFILTER
It is used for the ultrafiltration during the
CPB to minimize hemodilution.
Molecules up to a molecular weight of 20,000 Da
are removed.
Its conserves platelets, albumin &
Coagulation factors.

56. HAND CRANK
Vital
Emergency Situations
Electrical or Mechanical
Failure

57. PRIMES

58. HEMODILUTION AND PRIMING SOLUTION
• Rapid initiation of CPB without the risk of air embolism.
• Both Arterial and Venous Limbs primed with adequate reserve volume.
• No best solution.
• Ideal prime should be capable of maintaining oxygen delivery, carbon
dioxide and physiological homeostasis.

59. HISTORICAL PERSPECTIVE
• Blood was used to prime CPB circuit.
• Crystalloids in the prime improved outcome due to hemodilution.
• Zuhdi et al developed the process of hemodilution in 1961.
• DeWall confirmed the benefits of hypothermic hemodilution.

60. BENEFITS OF HEMODILUTION
• Decreases blood viscosity - Improves regional blood flow.
• Improved oxygen delivery to tissues.
• Decreased exposure to homologous blood products.
• Improved blood flow at lower perfusion pressure especially during
hypothermic perfusion

61. HEMATOCRIT ON CPB
< 30 % HCT at 300C,
25 % HCT at 250C.
< 20% = abnormal distribution of blood flow to organs.
>34% in CABG = greater risk of Q wave infarct, worsened LVEF and
increased mortality.

62. PRIMING
1. BLOOD PRIMING
2. NON-BLOOD PRIMING:
A] CRYSTALLOID PRIMES
Dextrose
Balanced Crystalloid Fluid
Mannitol
B] COLLOD PRIMES
Albumin
Gelatins
Dextrans
Hydroxymethyl Starch

63. BLOOD PRIMING
• Reduces the degree of hemodilution
• Indications
• Pediatric Patients
• Low hematocrit.
• Blood is a non Newtonian fluid. Its viscosity depends on flow rates.

64. WATER
NEWTONIAN
SAME VISCOSITY
KETCHUP
NON - NEWTONIAN
VARIABLE VISCOSITY

65. POISEUILLE EQUATION
Q= Flow
P1dP2= pressure drop along a tube of radius R and length L
u=viscosity
Jean Léonard Marie
Poiseuille

66. NON-BLOOD PRIMING - Crystalloid Prime
• DEXTROSE - Hypotonic and Acidic
Functions.
1. Less damage to RBCs
2. Diuresis.
3. Reduced Post OP Fluid requirement.
Disadvantages
1. Metabolism – Acidosis.
2. CPB – Hyperglycemia and Raised Serum Insulin levels. Further increase in Glucose.
3. Diabetics.
4. CPB related neurological complications.

67. NON-BLOOD PRIMING - Crystalloid Prime
• BALANCED CRYSTALLOID FLUID
• Neutral pH and concentration of electrolyte similar to that of human plasma.
• Ringer’s lactate and Hartmann’s solution are typical examples.
• Caution in diabetic patients, as lactate may be converted in to glucose in vivo
through the gluconeogenic pathway.

68. NON-BLOOD PRIMING - Crystalloid Prime
• MANNITOL
• Mannitol is hypotonic, low molecular weight crystalloid, stimulates diuresis.
• Protective effect on renal function.
• As a volume expander, mannitol draws fluid initially across the capillary into
the plasma. Then it rapidly diffuses volume of the whole extracellular phase
by withdrawing water from the body cells.

69. NON-BLOOD PRIMING - Colloid Prime
• ALBUMIN
• Molecular weight 69000 daltons.
• 75% to 80% of the plasma oncotic pressure.
• Albumin prime reduces post-operative bleeding.
• Albumin can induce anaphylactic or anaphylactoid reactions.

70. NON-BLOOD PRIMING - Colloid Prime
• DEXTRANS
• Molecular weight 40,000 - 70,000 daltons.
• Polysaccharide produced from sucrose by the bacterium leuconostoc mesenteroides.
• Mobilizes water from the extracellular into the intravascular space.
• Rapidly eliminated by the kidneys.
• Reduces blood viscosity and prevents the adhesion of leukocytes in the microcirculation.

71. NON-BLOOD PRIMING - Colloid Prime
• GELATINS
• Obtained from bovine collagen.
• Molecular weight 30,000 to 35,000 daltons.
• Types
• Urea Linked Gelatin
• Succinyl linked Gelatin.
• Disadvantage –High incidence of anaphylactoid reactions compared with
other artificial colloid.

72. NON-BLOOD PRIMING - Colloid Prime
• HYDROXYETHYL STARCH
• Synthetic colloid that consists of hydroxyethylated polymers of glucose
derived from amylopectin.
• Has similar clinical effects of volume expansion in cardiac surgical patients
with low incidence of anaphylactoid reactions like albumin.

73. ADDITIONAL COMPONENTS IN PRIMING FLUID