{"componentChunkName":"component---src-templates-html-tsx","path":"/systems/01-cardiovascular-~cs-~vs/7--procedures/mcs---cardiopulmonary-bypass---cpb","result":{"pageContext":{"slug":"/systems/01-cardiovascular-~cs-~vs/7--procedures/mcs---cardiopulmonary-bypass---cpb","crumbs":[{"slug":"/systems","display":"Systems"},{"slug":"/systems/01-cardiovascular-~cs-~vs","display":"01 Cardiovascular Cs Vs"},{"slug":"/systems/01-cardiovascular-~cs-~vs/7--procedures","display":"7 Procedures"}],"name":"MCS | Cardiopulmonary Bypass | CPB","html":"\n\n\n\n\n\n\n

Cardiopulmonary Bypass

Last modified: 17 July 2022, 8:29:46 AM AEST

Gems1 / 14

larger reservoir\n
- allows perfusionist to adjust volume of circulation as needed by surgeon
\n
input from cardiotomy suckers also

Lines2 / 14

In\n
- Coronary / cardiotomy suction
- Ventricular suction\n
  - Gentle aspiration from LV/PA to prevent overdistension
  \n
- Venous drainage by gravity
\n

Non-cardioplegic techniques3 / 14

intermittent aortic cross-clamping

Temperature management4 / 14

via bypass circuit
hypothermia\n
- ice around heart
- ⬇MVO2
- ⬆ischaemia tolerance of vital organs
- worsens coagulopathy
\n
rewarming\n
- afterdrop after separation from bypass\n
  - minimise with\n
    - slow / prolonged rewarming
    - peripheral vasoD (GTN/SNP)
    \n
  \n
- CV instability
- ⬆ICP
\n

Priming of circuit5 / 14

1.5-2.5 L
Colloid / crystalloid
Blood to maintain Hct

Anticoagulation6 / 14

Check baseline ACT = Activated Clotting Time
Heparin\n
- 300-400 iu/kg, eg. 25,000 iu
- via CVC after checking patency
\n
Check ACT after 3-5 minutes
Target\n
- ACT 3x normal/baseline
- ACT >480
\n
Timing\n
- Do not go on CPB until ACT confirmed
- In emergency, give a large dose and go on
\n
Initiate CPB
Monitor ACT every 30 minutes

Tests for heparin ACT7 / 14

APTT = Activated Partial Thromboplastin Time\n
- Pro = cheap
- Dis = slow
\n
Anti-Xa assay\n
- Laboratory test
- Not widely used, poor inter-laboratory correlation
\n
ACT\n
- Pro = POC test, cheap, rapid
- Con = poor correlation with clinical anti-Xa activity
- Prolonged ACT = thrombocytopenia, antiplatelets, ⬇temp, haemodiluation,
\n
Heparin concentration monitoring\n
- Con = expensive, not widely available
\n

Inadequate ACT8 / 14

Drug error\n
- not administered
- wrong drug
- CVC not patent
- CVC not flushed
\n
PK factors\n
- heparin is highly protein bound
- ⬆protein = acute illness, malignancy, peri-partum
\n
Lack of AT3

Initiation9 / 14

C\n
- Priming of CPB circuit
- SBP 90-100 to ⬇risk aortic dissection at aortic cannulation
\n
H = Anticoagulation\n
- heparin 300 iu/kg
- target ACT > 480 secs at 3 mins
\n

Maintenance10 / 14

C\n
- Maintain perfusion pressure 50-70 mmHg
\n
E\n
- Hypothermia for organ protection
\n
F\n
- Acid-base management
\n

Separation11 / 14

B = ventilator on, 100% O2
C =\n
- HR > 70, treat high/low HR
- INO\n
  - RV\n
    - pace at 90-100
    - ephedrine, mil, dob, Ad
    - Inh iloprost 20 mcg / milrinone 5 mg
    - mechanical support
    \n
  - LV\n
    - exclude LVOTO
    - atrial pacing
    - ephedrine / milrinone / dobutamine / Ad
    - mechanical support
    \n
  \n
- PL\n
  - under = pump blood, FFP, 4% albumine
  - dilated RV = cautious filling, consider washed pump blood
  \n
- AL\n
  - MAP < 70 = NAd, VP, MB
  - MAP > 90 = Mg, analgesia, anaesthesia, GTN, SNP
  \n
- Ensure de-airing
\n
D\n
- Anaesthesia on
- Analgesia
- NMBA?
\n
E\n
- Temp > 35.5
- Rewarm = Bair hugger, fluid warmers
\n
F\n
- K < 6
\n
H\n
- Hct > 25%
- Coagulation\n
  - ROTEM
  \n
\n
Successful wean?\n
- Protamine 0.6 mg / 100 iu heparin
- Check ACT
\n

Complications12 / 14

Circuit / mechanical\n
- Arterial cannulation\n
  - Haemorrhage, dissection
  - Plaque disruption
  \n
- Oxygenator / pump failure
\n
C = Cardiovascular\n
- fluid overload, esp paediatrics
- myocardial stunning
- emboli (air / thrombus / debris)
\n
D = Neuro\n
- neurological dysfunction\n
  - hypoperfusion (watershed infarcts)
  - cerebral oedema (pump-head)
  \n
\n
E = Endocrine\n
- Hypothermia
- SIRS
\n
F = Renal\n
- Fluid depletion = AKI
- Fluid overload
- Electrolyte disturbance
\n
G = GIT\n
- Hypoperfusion of abdominal organs
\n
H = Haematological\n
- platelet dysfunction
- coagulopathy\n
  - consumption of clotting factors
  \n
- blood transfusion
- complement activation and ARDS (post-pump lung)
- haemolysis
- haemodilution
\n
I = Immune\n
- ⬆PG, inflammatory markers, cytokines
\n

Heparin Resistance13 / 14

Mostly Anti-thrombin deficiency\n
- congenital
- acquired
\n
Treatment\n
- Give more heparin
- Risk of heparin rebound
- FFP 2-4 units ~ 1 iu AT/mL of FFP
- AT concentrate 500-100 iu
\n

References14 / 14

Basics of cardiopulmonary bypass, IJA 2017

https://alfpropsux.files.wordpress.com/2016/07/cardiac-cpb-wean.pdf

Talk, Saul Judelman

\n"}},"staticQueryHashes":["3649515864","63159454"]}