Problems in CPB
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Transcript Problems in CPB
Problems in Cardiopulmonary
Bypass
1
Introduction
Perfusion Incident frequency
Identify possible problems during CPB
Outline remedial action
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Incident Frequency
Date
Author
Country
1980 Stoney
US
Incidence / Permanent
accidents
injury/death
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 / 1400
1 / 130
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Incident 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
DIC
air embolism
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Topics for Discussion
Mediation of Patient’s immune system
response
Unusual syndromes
Oxygenator problems
Embolic events Protocol for Gross Air
Embolism
5
Systemic Inflammatory
response
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
response
1. Biocompatible materials
•Albumin in priming fluid
•Heparin coating - ionic
surface grafting covalent -
benzalkonium heparin
•Endothelial-like surfaces
phosphorylcholine
trillium
-
Carmeda
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Mediation of Inflammatory
response
2. Leucocyte depletion
3. Isolation of Cardiotomy suction
11
Anti-thrombin III deficiency
In the absence of adequate circulating
AT-III heparin has little or no effect
retarding blood coagulation.
Congenital AT-III deficiency
Acute venous thrombosis
DIC
Liver cirrhosis
12
AT III - Diagnosis & action
ACT still low after Heparin bolus
Repeat bolus ( 30 - 40mg / Kg )
ACT still low – give 2 units FFP
Recheck ACT
On bypass add further FFP as reqd
13
Microaggregates - Cold
agglutinins
gp1 : Immunoglobulin M class directed
against erythrocyte I antigen – wide thermal
range 4 to 32C
gp2 : narrow thermal range 0 - 10C
Clotting / grainy appearance
Interfere with cardioplegia distribution &
myocardial protection.
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Cold agglutinins –
management strategy
Rewarm pat to 320C
Switch to warm blood cardioplegia
Sample to haematology to determine
thermal amplitude
Pre-op plasmapheresis for patients with
known agglutinins will remove most of the
serum antibodies.
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Malignant 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
16
M.H. - remedial action
Stop all volatile anaesthetic agents
FiO2 to meet metabolic demand
Administer Dantrolene sodium IV
Correct acidosis + hyperkalaemia
Use IV and surface cooling to control temp
Give mannitol + frusemide to maintain
urine output of at least 2ml/Kg/hr
17
Sickle 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 –
management strategy
Disease :
Divert venous blood to cell salvage / plasmapheresis
to separate plasma and platelets
Replace with RBC, FFP, colloid + crystalloid
Trait :
Keep O2 saturations high
Avoid acidosis
Avoid hypothermia
Warm blood cardioplegia
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Methaemoglobinaemia
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 enzymes
Drug reaction – e.g. nitroglycerine,
isosorbide dinitrate, sodium nitrate
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Remedial Action
Withdraw all possible causative agents
Administer 1% methylene blue infusion
1 – 3mg/kg over 5 min
Doses > 7mg/kg are toxic
High dose Vitamin C and/or exchange
transfusion in severe cases
21
Oxygenator Problems
Physical attrition
Gas exchange capability
Inadequate anticoagulation
Heparin resistance
AT III deficiency
Administration of Protamine !
22
Sources 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 Emboli
Gaseous
• 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
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
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 Protocol
Perfusion
Surgical
Anaesthetic
Post operative care
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Perfusion
Discontinue bypass – clamp art + ven lines
Identify origin of problem
Reprime CPB circuit & art cannula
Retrograde SVC perfusion 1-2 LPM
Reinstitute bypass - temp (22 – 30o C)
Systemic pressure
FiO2 = 100%
Off bypass @ 34o C
28
Surgical
Clamp & remove aortic cannula
Cannulate SVC or connect to SVC cannula
Retrieve blood/air exiting aorta via vent
When no more air is visible at aortotomy
-- Re-cannulate aorta – reinstitute bypass
Bleed air from coronary arteries
Complete Surgical procedure
29
Anaesthetic
Place patient in steep Trendelenberg position
Compress carotid arteries
Consider administering :
Steroids
Mannitol
Antiplatelet agents
30
Post Bypass Management
Ventilate patient on 100% oxygen
Institute slight hyperventilation
Rewarm to normothermia over 24hrs
Place patient in reverse trendelenberg posn
Avoid hyperglycaemia + hyponatraemia
Consider Hyperbaric oxygen treatment
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