Cardio Pulmonary Bypass Machine Hardware and Primes.pptx

CPB Hardware and Primes. A comprehensive presentation

1. CARDIOPULMONARY BYPASS HARDWARE AND PRIMES

2. “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

3. CARDIOPULMONARY BYPASS EQUIPMENTS

4. 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

5. CARDIOPULMONARY BYPASS CIRCUIT

6. CARDIOPULMONARY BYPASS CIRCUIT Oxygenation and elimination of CO 2. Circulation of blood. Systemic cooling and re-warming. Diversion of blood from the heart.

7. BASIC SCHEMATIC

8. CARDIOPULMONARY BYPASS CIRCUIT

9. CARDIOPULMONARY BYPASS PUMPS

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

11. 4 Types Roller Pumps Centrifugal Pumps Pulsatile Pumps Non Occlusive Roller Pump BLOOD PUMPS

12. 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 .

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

14. ROLLER PUMPS – OCCLUSION.

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

16. 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

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

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

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

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

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

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

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

24. 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.

25. 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

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

27. 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 .

28. 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

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

30. 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

31. 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

32. 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.

33. CANNULA

34. 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

35. DOUBLE LUMEN ARTERIAL CANNULA

36. 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

37. PERFUSION CANNULA CHART

38. 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

39. 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 ]

40. VAVD

41. 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

42. 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.

43. 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

44. 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 . D ecreased thrombogenecity . (No evidence) However, inflammation related to complement activation is decreased.

45. 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

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

47. LEVEL SENSOR AND BUBBLE DETECTOR

48. 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.

49. 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.

50. 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 O 2 or CO 2 or Nitrous Oxide. Pore size- 0.2 µm.

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

52. 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.

53. HAND CRANK Vital Emergency Situations Electrical or Mechanical Failure

54. PRIMES

55. 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.

56. 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.

57. 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

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

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

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

61. WATER NEWTONIAN SAME VISC OSITY KETCHUP NON - NEWTONIAN VARIABLE VISC OSITY

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

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

64. 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.

65. 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.

66. 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.

67. 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.

68. 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.

69. 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.

70. ADDITIONAL COMPONENTS IN PRIMING FLUID