3.5 CPB 2

Question 1

Clinical indications for CPB

Theatre

Answer 1

Theatre

1. Heart valve surgery
2. On pump CABG
3. Structural heart surgery (congen)
4. Pulmonary vasculature surgery
5. Prox thoracic aorta
6. Deep induced hypothermia

Question 2

Clinical indications for CPB

ICU

Answer 2

For respiratory failure
vv ecmo

CV failure
VA ecmo

Rewarming refractory hypothermia

Refractory cardiogenic shock

Brdige to transplant end stage cardiac failure

Question 3

Complications a/w CPB

Answer 3

Circuit

Patient
- CNS
Resp
CVS
GI
Renal
other

Question 4

Complications a/w CPB

Circuit

Answer 4

1. Plt activiation
2. Activation of clotting cascade and complement pathyway
3. Cell damage
4. Particulate or gas emboli formation

5. Cannulation 
V
a haemorrhage
b Organ/vessel damage
c Red preload
d Air embolus during cannula insertion

A
Haemorrhage
emboli athero sclero plaque / air into circ
Dissection
Malposition

Question 5

Complications a/w CPB

Patient

CNS

Answer 5

Overall incidence .5-1%

CNS

1. Focal neurology abnormality 1-6% post op
   - Main form from cpb
   - Hemiparesis / sensory neural hearing loss / visual field defx
   - RF Age premorbid CVD / Carotid A disease, Valve surgery, preop LV fxn, long bypass time
2. Global neuro abnormal
   - Overall decrease level awareness 1-3d postop
   - Non sedative persistent coma >24h postop mortality factor
   - neuropsychological - early postop emotion / memory / attention defx

Question 6

Complications a/w CPB

Respiratory

Answer 6

1. Atelectasis common
   ↑ w/ pleura open IMA graft
2. ↑ A-a gradient + ↓ FRC
   -shunt hypoxaemia + increase requirement for vent
   ALI / ARDS 1-2% cases
3. Sputum retention *post sternotomy
   ↑ risk pneumonia
   ↑w/ comorbid lung disease

Question 7

Complications a/w CPB

CVS

Answer 7

1. Post bypass cardiac fxn relates to preop state
2. Ventricle often stiff w/ ↓ immed postop
   tolerates brady poorly
3. Arrhythmia common
   hypox / electrolyte
   pacing wires routine treat brady arryh
4. Low vascular tone common immed postop
   require vpresor to maintain MAP

Question 8

Complications a/w CPB

GIT

Answer 8

GIT

1. 20% Patients postop elevated bili
2. Risk UGIB higher
   postop peak day 10
3. Pancreatitis

Question 9

Complications a/w CPB

Renal

Answer 9

1. 1-4% patients
   often reversible
2. Significant predictor mortality
   especially requiring RRT
3. ↑risk - renal disease
   long bypass
   age
   poor CO

Question 10

Complications a/w CPB

OTHER

Answer 10

1. Poor platelet fxn + coagulopathy
   require transfusion PRC + Clotting products
2. Peripheral insulin resistance w/ poor glucose control
3. ↑ Total body water increased capillary permeability
4. embolic occlusion / compartment syndrome
   theoretical rare
5. Gen Myopathy - pt remain ICU + ventilated