Design & principles of operation of bubble oxygenators of linear & concentric design

Oxygenator

• Venous blood first enters a mixing chamber, where fresh gas flows into the blood through a screen, which causes small bubbles to form. The blood & bubbles coalesce; sufficient time is allowed in this section for adequate gas exchange to occur prior to defoaming in the second section

Defoamer

• The mixture of blood & gas which emerges from the bubble column must be defoamed

• An open sponge or mesh coated with antifoam is placed in the path of the oxygenated blood

• Defoamer destabilises bubbles, causing them to collapse

• The wire mesh serves to mechanically restrain bubbles

Arterial Reservoir

• Used to store arterial blood

• Compensates for inevitable flow discrepancies between the passively flowing venous tubing and the pump driven arterial tubing: allows the perfusionist time to react [add volme, reduce flows]

• Further facilitates debubbling by allowing blood to briefly stagnate & thus facilitate bubble elimination by allowing them to float to the top of the reservoir

• Blood exists from the reservoir from the bottom, away from any bubbles floating to the top

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