Dr S Parthasarathy MD DA DNB MD Acu Dip DiabDCA Dip Software statistics Phd physio Mahatma Gandhi Medical college and research institute puducherry India ID: 998364
Download Presentation The PPT/PDF document "Basics of cardiopulmonary bypass" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
1. Basics of cardiopulmonary bypass Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab.DCA, Dip. Software statistics, Phd (physio)Mahatma Gandhi Medical college and research institute , puducherry , India
2. Why do we need ?? Unlike nasal polyp ,gut Cardiac surgery needs a motionless, bloodless surgical field
3. Definition Cardiopulmonary bypass(CPB) is a form of extracorporeal circulationIt temporarily takes over the function of the heart and lungs during surgery, maintaining the circulation of blood and the oxygen content of the bodyDon’t think it stops with two functions ??
4. four major functions1) oxygenation and carbon dioxide elimination, (2) circulation of blood, (3) systemic cooling and rewarming, (4) diversion of blood from the heart to provide a bloodless surgical field.
5. When to use ?? Cardiac NoncardiacThoracic aortic surgeries , mediastinal masses, we cant intubate in a respiratory obstruction , lung transplantation, liver transplantation DHCA in neurosurgical procedures
6. The process Typically, blood is gravity drained from the heart and lungs to a reservoir via venous cannulation and tubing, returned oxygenated to the cannulated arterial system by utilizing a pump and artificial lung (oxygenator or gas-exchanger).
7.
8. Venous arterial + venous
9.
10. Gravity based venous flow Height Tubings CVP Determine venous flow arterialAorta is preferred – large , less pressure more flow , dissection chance is less
11. Oxygen flow meter and blender
12. Oxygenator and heat exchanger Water
13. oxygenatorsprovided gas exchange by contact of a blood film to an oxygen rich atmosphere (e.g. disc oxygenators) by bubbling oxygen through blood (e.g. bubble oxygenators). Pump ?? Modern day oxygenators provide gas exchange to blood through a membrane(e.g. sheet and hollow-fibre oxygenators).
14. Bubble oxygenator
15. Need to have a defoaming matrix
16. artificial lungThe artificial lung material is more gas permeable to CO2 than O2; silicone membranes have a CO2:O2 transmission ratio of about 5 : 1.0.05 to 0.3 µm ( PP, area but thickness) law ?? CO2 transfer – difficult to predict Sweep gas !!
17.
18. Artificial lungs Diffusional distances are greater (approximately 200 mm in comparison with 10 mm in the human alveolus) surface area for gas exchange is 1.7–3.5 m2 compared with 70–100 m2 in the human lung.
19. Arterial line
20. HemothermCPB is performed under systemic hypothermia (typically a nasopharyngeal temperature of 25–32C)Single tank and double tank are available
21. Arterial and venous cannula
22. The tubing and cannulae are manufactured of clear polyvinyl chloride, while the oxygenator casing and connectors consist of polycarbonate.
23. Why should we so many ??
24.
25.
26. Cardioplegia Solution of potassium – aortic root – diastolic arrest concentration of approximately 20 mmol litreAnterograde or retrograde Warm or coldblood or crystalloid 1:2 or 1:1 0r 1:4 mixing Glutamate, aspartate, mannitol Nicorandil or esmolol cardioplegia
27.
28.
29. cardioplegia ?? Non-cardioplegic techniques include the use of moderate systemic hypothermia (i.e. core temperature of 30–32C) with short periods of aortic cross-clamping and ventricular fibrillation (VF).Also beating heart surgeries !!
30. Cardiotomy and vent The suckers attached to the CPB circuit allow blood to be salvaged from the operative field to be returned to the circuit via the reservoir.
31. Vent suckersspecifically used to drain blood that has not been directly removed from the heart by the venous pipes. The most common sites for placing dedicated vents are:• the aortic root;• the left ventricle;• the right superior pulmonary vein;• the left ventricular apex; • the left atrium or pulmonary artery.
32. Why we need venting to prevent distension of the heart;• to reduce myocardial re-warming;• to evacuate air from the cardiac chambers during the de-airing phase of the procedure;• to improve surgical exposure; • to create a dry surgical field, especially during the distal coronary anastamosis phase of CABG surgery
33.
34. Roller pumps --Produces flowNearly occlusive Nonpulsatile or pulsatileLow flow and low cost afterload – ok Low priming volume
35. Problems Tubing rupture Hemolysis Air embolism
36. Centrifugal pumps Produces pressureSuperior for right or left heart bypassPreferred for long-term bypass nonocclusive After load sensitiveBut large priming vol and cost ??
37. Centrifugal pumps CPs consist nest of smooth plastic cones within a plastic casing. These impellers or cones are magnetically coupled (at the base) with an electric motor when rotated rapidly, generate a centrifugal force to the blood, which is received by the pump bodyCF == Mass of blood * radius of pump head* speed of revolutions (RPM)
38. Filters Haemofilters (haemoconcentrators or ultrafilters) are utilized in CPB circuitry to remove excess fluid and electrolytes, attenuate inflammatory mediators and raise haematocrit. These devices mainly consist of a hollow-fibre semipermeable membrane to allow the passage of water and electrolytes from the blood to a filtrate compartment.
39.
40.
41. Inline monitoring systems
42. Aortic cross clampcross-clamp is placed across the ascending aorta above the coronary ostiaand proximal to the aortic cannula, isolating the coronary circulation preventing blood entering the chambers of the heart.ACC time ??
43. Priming solution The cardiopulmonary bypass (CPB) circuit must be primed with a fluid solution, (1500 ml to 2 litres) so that adequate flow rates can be rapidly achieved on initiation of CPB without risk of air embolism. Crystalloid, colloids and blood Mannitol, sodabicarb, heparin, steroids – additives 17 % hematocrit tolerated
44. Back to square one !!
45. Partial bypass ?? T.AOperation No oxygenator
46. CPB starts an extremely complex and multifactorial response involving activation of complement, platelets, neutrophils, monocytes and macrophages, thus initiating the coagulation, fibrinolytic and kallikrein cascades.
47. Neurologic dysfunction, pulmonary dysfunction,renal dysfunction, hematologic abnormalities.SIRS
48. The fundamentals Check and prime Monitoring lines, temperature, blood gases, urine _ GA- narcotics Incision, sternotomy Heparinization Cannulation – pump on ACC and cardioplegia, surgery – oxygen ! Agent? ACC off , ( O2 + agent) warm, investigations, TEE, hemodynamics, pump off , protamine, cannulae off – suturing
49. Thank you