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Problems in Cardiopulmonary Problems in Cardiopulmonary Bypass Bypass
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IntroductionIntroduction
Perfusion Incident frequencyIdentify possible problems during CPBOutline remedial action
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Incident FrequencyIncident Frequency
Date Author Country Incidence / accidents
Permanent injury/death
1980 Stoney US 1 / 300 1 / 1000
1981 Wheeldon UK 1 / 300 1 / 1500
1986 Kuruz US 1 / 100 1 / 1000
1997 Jenkins Australia 1 / 35 1 / 1300
2000 Mejak US 1 / 130 1 / 1400
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Incident distributionIncident distribution
Stoney Wheeldon Kuruz Jenkins Mejak
DIC Elec failure Protamine reaction
Heater/cooler problems
DIC
air embolism air embolism Oxy failure air embolism Protamine reaction
Elec failure Oxy failure Elec / mech failure
Protamine reaction/prob
Ao dissection / cannula prob
Mech failure Mech failure Drug error Oxy failure Oxy failure
Oxy failure DIC air embolism air embolism
DIC
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Topics for Discussion Topics for Discussion
Mediation of Patient’s immune system response
Unusual syndromesOxygenator problemsEmbolic events Protocol for Gross Air
Embolism
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Systemic Inflammatory Systemic Inflammatory responseresponse
Platelet adhesion, activation of Factor XII Cascade activation :
kallikrein kinin-bradykinin Fibrinolytic Complement - C3a + C5a
leucocyte activation
oxygen free radicals
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Mediation of Inflammatory Mediation of Inflammatory response response
1. Biocompatible materials
•Albumin in priming fluid
•Heparin coating - ionic - benzalkonium heparin surface grafting -
covalent - Carmeda
•Endothelial-like surfaces - phosphorylcholine
trillium
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Mediation of Inflammatory Mediation of Inflammatory responseresponse
2. Leucocyte depletion
3. Isolation of Cardiotomy suction
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Anti-thrombin III deficiencyAnti-thrombin III deficiency
In the absence of adequate circulating AT-III, heparin has little or no effect retarding blood coagulation.
Congenital AT-III deficiencyAcute venous thrombosisDICLiver cirrhosis
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AT III - Diagnosis & actionAT III - Diagnosis & action
ACT still low after Heparin bolusRepeat bolus ( 30 - 40mg / Kg )ACT still low – give 2 units FFPRecheck ACTOn bypass add further FFP as reqd
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Microaggregates - Cold Microaggregates - Cold agglutininsagglutinins
gp1 : Immunoglobulin M class directed against erythrocyte I antigen – wide thermal range 4 to 32C
gp2 : narrow thermal range 0 - 10CClotting / grainy appearanceInterfere with cardioplegia distribution &
myocardial protection.
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Cold agglutinins – Cold agglutinins – management strategymanagement strategy
Rewarm pat to 320CSwitch to warm blood cardioplegiaSample to haematology to determine
thermal amplitudePre-op plasmapheresis for patients with
known agglutinins will remove most of the serum antibodies.
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Malignant HyperthermiaMalignant Hyperthermia
Inherited disorder – rapid temp to 42°C in response to volatile anaesthetic agents
Abnormal calcium metabolism - myoplasmic ionic calcium
Metabolic rate, resp + met acidosis, K+ , lactate + pyruvate, tachycardia, temp
Massive muscle swelling, Pul oedema, DIC & acute renal failure 70% mortality
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M.H. - remedial actionM.H. - remedial action
Stop all volatile anaesthetic agentsFiO2 to meet metabolic demandAdminister Dantrolene sodium IV Correct acidosis + hyperkalaemiaUse IV and surface cooling to control tempGive mannitol + frusemide to maintain
urine output of at least 2ml/Kg/hr
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Sickle Cell DiseaseSickle Cell Disease
Low O2 sat +/- hypothermia will cause sickle cells to clump + precipitate
Disease : Pats with 50% Haemoglobin S cells will sickle @ 85% O2 sat
Trait : Pats with 45% Haemoglobin S cells will sickle @ 40% O2 sat
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Sickle Cell Disease – Sickle Cell Disease – management strategymanagement strategy
Disease :
Trait :
Divert venous blood to cell salvage / plasmapheresis to separate plasma and plateletsReplace with RBC, FFP, colloid + crystalloid
Keep O2 saturations highAvoid acidosisAvoid hypothermiaWarm blood cardioplegia
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MethaemoglobinaemiaMethaemoglobinaemia
Severe cyanosis of arterial blood ( often appears chocolate brown rather than blue ) in spite of high pO2
Haem ion oxidised from ferrous (Fe 2+) to ferric (Fe 3+) state
Hereditary deficiency in control enzymesDrug reaction – e.g. nitroglycerine,
isosorbide dinitrate, sodium nitrate
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Remedial ActionRemedial Action
Withdraw all possible causative agentsAdminister 1% methylene blue infusion
1 – 3mg/kg over 5 minDoses > 7mg/kg are toxic High dose Vitamin C and/or exchange
transfusion in severe cases
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Oxygenator ProblemsOxygenator Problems
Physical attrition Gas exchange capabilityInadequate anticoagulation
Heparin resistanceAT III deficiencyAdministration of Protamine !
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Sources of EmboliSources of Emboli
Particulate
• Oxygenator - Polypropylene / polycarbonate
• CPB circuit - PVC / silicone (spallation)
• Patient - plaque calcium platelet / fibrin aggregates lipid globules muscle / connective tissue fragments
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Sources of EmboliSources of EmboliGaseous
• Cannulation
• Venous air entrainment – (VAVD?)
• Inadequate de-airing of the heart
• Inappropriate vent suction
• Centrifugal pump – retrograde flow
• IABP deflation during aortotomy
• Temperature Gradients
• Catastrophic gross air embolism
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Protection Against Embolic Protection Against Embolic Events ( 1 )Events ( 1 )
Particulate
0.5 micron Pre-bypass filter
40 micron Arterial line filter
120 micron cardiotomy reservoir filter
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Protection Against Embolic Protection Against Embolic Events ( 2 )Events ( 2 )
Gaseous
•Microemboli - arterial line filter + purge line - elimination of entrained venous air - vent line – one-way pressure relief valves
•Macroemboli - oxygenator resevoir level sensor - arterial line filter + purge line
- ultrasonic bubble detector in art line - anti-siphon valve / software for
centrifugal pumps - CO2 insufflation
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Gross Air Embolism Incident - Gross Air Embolism Incident - ProtocolProtocol
PerfusionSurgicalAnaestheticPost operative care
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PerfusionPerfusion
Discontinue bypass – clamp art + ven linesIdentify origin of problemReprime CPB circuit & art cannulaRetrograde SVC perfusion 1-2 LPMReinstitute bypass - temp (22 – 30o C)
Systemic pressure FiO2 = 100%
Off bypass @ 34o C
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SurgicalSurgical
Clamp & remove aortic cannulaCannulate SVC or connect to SVC cannulaRetrieve blood/air exiting aorta via ventWhen no more air is visible at aortotomy
-- Re-cannulate aorta – reinstitute bypassBleed air from coronary arteriesComplete Surgical procedure
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AnaestheticAnaesthetic
Place patient in steep Trendelenberg positionCompress carotid arteriesConsider administering :
Steroids Mannitol Antiplatelet agents
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Post Bypass ManagementPost Bypass Management
Ventilate patient on 100% oxygenInstitute slight hyperventilationRewarm to normothermia over 24hrsPlace patient in reverse trendelenberg posn
Avoid hyperglycaemia + hyponatraemiaConsider Hyperbaric oxygen treatment
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