3. What harm an Oxygenator does?
• Hemodilution and allogenic transfusion
• Trauma to blood cells
• SIRS
• GME
4. An Ideal Oxygenator
• Less priming volume.
• As Bio compactable as possible.
• Maximum rated flow
• Minimum blood contact area.
• Minimal pressure drop so that the trauma.
• Effective in managing GME.
13. Membrane Surface Area
• Signifies area available for gas exchange
• Area of contact of blood with oxygenating surface
• Gas Exchange – Diffusion
• Aggregation of formed elements
• Potential source of SIRS
• Physiological Coating in most Oxygenators
16. Rated flow
Max (rated) blood flow - upper limit of blood
flow through Oxygenator.
that can safely conduct the process of gas
transfer ensuring SO2 > 95%
at standard Venous inlet conditions (with
SO2 of 65 ± 5 % at the inlet of
Oxygenator with Hb of 12 ± 1% at 37 ± 2deg
C,base excess of 0 ± 5 mEq/L and a pCO2
of 45 ± 5 mmHg)
17. Reference Blood flow
Max possible flow ensuring PO2 > 100
mmHg
and PCO2 of 35mmHg under AAMI test
standards
(Hb: 12g/dl, Temp 37DegC,FiO2 100%,
SvO2 65%, Venous PCO2 45mmHg)
18. Rated or reference????
• Rated Flow – Performance in Clinically
recommended safe limits
• Reference Flow – Performance in Ideal
Environment.
Reference flow – OFF LABEL USE
(Not Recommended Clinically)
Raised GME, Membrane Rupture,etc
21. Oxygen Transfer
• Defined as Amount of Oxygen (ml) transferred per
minute at AAMI reference standards
(Hb: 12g/dl, Temp 37DegC,FiO2 100%,
SvO2 65%, Venous PCO2 45mmHg)
• Factor of Oxygenator Efficiency
24. CO2 transfer
• Defined as the amount of CO2 (ml) transferred
per minute of flow under AAMI reference
standards
(Hb: 12g/dl, Temp 37DegC,FiO2 100%, SvO2 65%, Venous
PCO2 45mmHg)
• Another marker of Oxygenator efficiency
27. Pressure Drop
Difference in pressure between the
oxygenator inlet and oxygenator outlet as per AAMI
reference standards
(Hb: 12g/dl, Temp 37DegC,FiO2 100%, SvO2 65%, Venous PCO2
45mmHg)
Oxygenator inlet - Highest pressurized area the
circuit
Important
• Trauma to formed elements,
• Resistance to blood flow,
• Formed element aggregation,etc
28. Important in neonates…
• Higher flows
• Longer CPB run
• Lower pressure drop - Lower Leukocyte
activation
The lesser … the better….
31. Heat Exchanger Performance
Two factors considered
Heat Exchanger Surface Area
Heat Exchanger Efficiency
Tested as per AAMI reference standards
(Heat Exchanger Inlet Temp = 30 Deg C
Outlet Temp = 40DegC
Water Flow = 10 to 15L per minute ,Hb = 12
g/dl )
• More Area – Better efficiency ???
34. GME production
• CPB - post op neurological sequelae
• Obstructive to microcirculation
• Destructive to capillary endothelium
• Micro emboli escapes the filters(< 40 microns)
• Smaller number ,smaller size- Normothermia
• Greater number and size- Hypothermic conditions
• Open purge line- lesser micro emboli
35. Capillaries - 4 µm to 9 µm
Arterioles – 10 µm to 50 µm
Metarterioles – 8 µm to 30 µm
Gaseous micro emboli are commonly indicated as
potential sources of neurological damage after CPB.
Brown WR et al: Longer duration of
cardiopulmonary bypass is associated with greater
numbers of cerebral micro emboli. Stroke 2000; 31;
707-13
36. Smaller micron sizes in Venous filters reduces the
amount & size of GME
RESERVOIR FILTER SIZE
KIDS 100 51 MICRONS
QUADROX NEONATAL 64 MICRONS
BABY RX 47 MICRONS
DIDECO 901 NA
MEDOS HILITE 1000 NA
37. • At 400 ml/min – Most GME eliminated
• At 700ml/min- RX 05 – Least no of GME
• RX 05 – least amount of GME to reach patient
