Transcript CPB Problems - Mike Poullis - Consultant Cardiothoracic

CPB Problems
Mike Poullis
Overview
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General
Cold Agglutinins
Sickle
Thalassaemia
Hereditary spherocytosis and eliptocytosis
Polycythemia
G6PD Deficiency
Pregnancy
SLE
VF
In General
• If patient warm and well
• Do CABG off pump
• Do CPB work warm with blood cardioplegia
Cold Agglutinins 1
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Agglutination and haemolysis of RBC
Cold causes Ab binding
Warm causes complement activation
Screen @ 4oC. If +Ve thermal amplitude test
Cold Agglutinins 2
• Monoclonal lymphoreticular tumours
• Polyclonal
– Mycoplasma
– Glandular fever
– CMV
Cold Agglutinins 3
• If polyclonal & elective, cancel and
reschedule in 4-6 weeks
• Warm CPB and plegia
• If cold blood
– Warm crystalloid, cold blood, use hot shot
• Plasmapheresis, polyclonal Abs, steroids
Sickle 1
• Sickle due to hypoxia, acidosis, infection, capillary
stagnation
• Homozygous sickle if sats < 85 %
• Heterozygous sickle if sats < 40 %
• Therefore venous problem
• Exchange transfusion, bicarb for venous ABG
acidosis, crystalloid or blood(with high Hb A), keep
warm
• Beware mechanical heart valves causing haemolysis
Thalassaemia
• Minor and major
• Give blood to make up anaemia
• No problems on CPB
Hereditary spherocytosis and
eliptocytosis
• Increased osmotic and mechanical fragility
• Beware mechanical heart valves causing
haemolysis
• Free haemoglobin possible
Polycythemia
• Hct ~70 %
• Bleed secondary to [clotting factors]
• Autotransfusion good
G6PD Deficiency
• 10 to 15% Afro Americans
• X linked
• Beware sulphonamides, Aspirin, Vit K,
?Sux
Pregnancy 1
• 1st trimester organgenesis, treatogenesis
warfarin converted to heparin
• 2nd trimester no organogenesis, normal
circulation
• 3rd trimester hyperdynamic circulation and
risk premature labour
Pregnancy 2
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Normal uterine blood flow 1-2 % CO
Pregnant uterine blood flow 10-15 % CO
No autoregulation
Fetal heart rate good monitor
Uterine blood flow reduced by alpha receptors
use adrenaline not phenylephrenine
Pregnancy 3
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Keep warm
Use pulsatile
BP > 60 to 70 mean (by flow not alpha blockers)
Hct >22
Rt flank elevated to reduce caval compression
Tocolytics terbutaline, ritodrine, pregesterone, Mg
Beware serum [k+]
• Lung
SLE
– interstitial lung disease, PA pressure
• Heart
– coronary
– valve,
– conduction
• Kidney
– renal failure
• Blood
– Lupus anticoagulant
– Neutrophil function with immunosuppression
• Brain
– encephalopahy
• Adrenal
– Steroid suppression
VF
• Before cross clamp
– Cross clamp and pleg
– Defib after a few minutes to reduce
subendocardial ischaemia
• After cross clamp
– [k+], lignocaine, suck blood out, Mg2+
– Repleg with warm blood to break reenterant
circuit