3.4 CPB 1

Question 1

What is a CPB circuit`

Answer 1

1. Machinery replaces function of H+L
   - allow native fxn stopped
   - bloodless + motionless field
2. Most drain under gravity large bore catheter from Venous circ
3. Return line art cannula to systemic circ
4. Coated compounds reduce coag + inflam activation

a heparin

b phosphorylcholine

Question 2

Heparin effects

Answer 2

inhibits thrombogenic response of blood to circuit

reduce clot formation

reduce total hep dose req

red A-a gradient

reduced PVR

Question 3

Phosphorylcholine effects

Answer 3

Antiinflamm
antithrombic

replicate cell membrane on surface

Question 4

Draw a basic CPB circuit

Answer 4

page 134

Question 5

Describe different components + functions standard circuti

Answer 5

1. Reservoirs
2. Oxygenator
3. Heat exchanger
4. Pumps
5. Arterial filter

Question 6

Resevoir

Answer 6

Venous - receives blood under gravity from venous cannula + suction

Cardiotomy
Receives blood low vol displacement cannula + suction

Question 7

Oxygenator

Answer 7

1. Membrane oxygenator
2. FGF thru middle fine capillary tubes blood circulates
3. FiO2 Determines PP O2
   FGF acts sweep to determine PacO2
   FGF inversely related to PaCO2
4. Efficiency falls with use
   microthrombi + proteinaceous debris
   = decrease SA available for gas exchange
5. Heparin cotaed oxygenators a/w increase post op platelet counts

Question 8

Heat exchanger

Answer 8

Allows manipulation blood temp from reservoir to alter core temp

Allow therapeutic hypothermia during cpb and resuscitation of refractory hypothermia

Question 9

Pumps

Answer 9

Suction from venous + cardiotomy reservoir direct into oxygenator and heat exchanger

Centrifugal commonly used
(prev roller pump trigger cell damage and inflam)

Question 10

Arterial filter

Answer 10

Removes gases + particulate emboli from blood

reduce microvascular occlusion complication from CPB
pore size 27-40um

Specialised leucocyte depletion filters
= decrease in renal injury post bypass