Cardiopulmonary bypass oxygenators-history,types,function

1. OXYGENATORS
By
Dr.VASANTHI
DNB-CARDIAC SURGERY
MADRAS MEDICAL MISSION

2. History
• Non membrane oxygenators :
– 1955 Lillehei/Dewall- 1st bubble oxygenator ewith
helix reservoir
– 1956 Kay/Cross –disk oxygenators
– 1962 cooley /beall –commercially available
disposable bubble oxygenator
– 1966 Dewall/Najafe/Roden – 1st disposable hard
shell oxy with bulit in heat exchanger

3. • MEMBRANE OXYGENATORS :
– 1955 KOLFF/BALZFER oxygenated blood through
polyethylene membrane(animals)
– 1958 – Clowes – teflon as membrane plate
oxygenator
– 1971 – kolobow –silicone membrane sheets
– 1985 J & J - 1st hollow fibre polypropylene oxy

4. IDEAL OF AN OXYGENATOR
• Safe and efficient
• Overcome barrier of diffusion distance
• Minimum trauma to blood cells
• Small priming volume
• Easily assmebled
• Minimize air embolism

5. • Gas transfer is proportional to partial pressure
difference and surface area and inversely
proportional to diffusion distance.

6. Mechanism
• oxygenator – blood and gas flow direction
will be perpendicular

9. Bubble oxygenator
• 3 components :
– Oxygenation chamber
– Defoamer
– Arterial reservoir

12. 1.Oxygenation chamber
• Bubble size - determined by disperser by
Orifice diameter, Gas flow rate, Blood
viscosity, Surface tension.
• sparging plate – polycarbonate plate
perforated with holes of precise dimension or
porous silicate
• Purpose : break the bulk gas into small
bubbles to allow gas exchange

13. • More the no.of bubbles- greater efficiency of
oxygenation
• Co2 diffusion is 25times > o2.Larger bubbles will
efficiently remove of co2
• Smaller bubbles will efficiently oxygenate but
poor in removal of co2
• Size : 3 — 7 mm to optimise both CO2 & O2 gas
transfer

14. 2.Debubbling/defoaming area
• Made up of Polyurethane or polyester (125-
175microm)
• Beads, sponges(polyurethane),shreds, meshes,
fabrics
• Coated with Silicon(antifoam ) reduces surface
tension of bubbles & prevents bubble formation .
Hence air embolism prevented

15. • 3. Arterial reservoir :Always positioned after
the defoaming area

16. • Advantage : easy to assemble, lower cost,
small priming vol, adequate oxy capacity
• Disadvantage : microemboli, blood cell
trauma, destruction of plasma protein due to
gas interface, defoaming capacity exhausted
with time ,excessive removal of co2

17. MEMBRANE OXYGENATOR

19. Configuration
Scrolled envelope Hollow fibre Parellel Plate

20. Microporous membrane

21. • Polypropylene is a heterogenous,
microporous,hydrophobic membrane
• Size- 0.03 to 0.07 Um in diameter
• Surface is hydrophobic & the pores are so
small, the blood water is not ultrafiltered;
inhibit serum leakage across the membrane

22. TRUE MEMBRANE OXYGENATOR
• COIL [Scrolled] TYPE: consists of silicone
rubber sheets coiled in a cylindrical fashion
• Silicone rubber is nonporous ; there is a
complete barrier between blood and gas.
• Eg: Sci-Med oxygenator

23. • Advantages-- Able to maintain stable CO2 &
O2 for long periods of time (weeks), Used
primarily in ECMO
• Disadvantages--Costly to manufacture, High
priming volume.

25. Thank u