A novel, compact oxygenator

Virtually all current blood oxygenators employ hollow fibre membranes.  In these devices, oxygen flows through the hollow fibres and blood flows around them.  Different manufacturers organize the flow paths differently.  For example, the hollow fibres may be straight with the blood flow at right angles to the fibres.  Other devices have fibres wound around a bobbin.  In all cases, oxygen diffuses through the fibres to oxygenate the blood and carbon dioxide diffuses from the blood through the hollow fibres into the gas (oxygen) stream.  The rate of oxygen transfer is limited by the average distance that oxygen molecules travel from the red blood cells to the membrane.  The oxygen transfer rate is then limited by how closely the hollow fibres can be packed.  If they are too far apart, the resistance to transfer is too high.  However, if they are too close, the fibres touch thereby blanking out part of the transfer area and hence reducing transfer rate.

Haemair has developed an oxygenator with parallel hollow fibres in which the blood flows parallel to the fibres.  This arrangement gives controllable oxygen and carbon dioxide transfer rates with reduced pressure drop.   The device is no longer under active development, but independent tests conducted in 2012 suggested performance comparable to or superior to leading oxygenators available at that time – see following performance charts:

Pressure drop as a function of blood flow rate

AE-1: Haemair prototype ECMO oxygenator, CPB: Commercial Cardiopulmonary Bypass Oxygenator

ECMO: Commercial ECMO Oxygenator

Oxygen Transfer rate as a function blood flow rate

AE-1: Haemair prototype ECMO oxygenator, CPB: Commercial Cardiopulmonary Bypass Oxygenator

ECMO: Commercial ECMO Oxygenator