Particle separation using ultrasound can radically reduce embolic load to brain after cardiac surgery.
BACKGROUND
Microembolism during cardiopulmonary bypass has been suggested as being the predominant cause of neurocognitive disorders after cardiac surgery. Shed blood, normally retransfused into the patient during cardiopulmonary bypass, is a major source of lipid microemboli in the brain capillaries. A newly developed technique based on acoustic standing-wave separation of particles in fluid in microchannels, with the capacity to remove lipid particles in blood, is presented.


METHODS
A separator consisting of eight parallel, high-fidelity microfabricated channels was actuated with an ultrasound field to create a standing wave. Three different concentrations of lipid particles (diameter, 0.3 microm) were added to blood samples with increasing hematocrits and introduced into the separator channels to separate lipid particles and erythrocytes.


RESULTS
The mean separation rates for lipid particles were 81.9% +/- 7.6% and for erythrocytes 79.8% +/- 9.9%, and both were related to the hematocrit level of the incoming blood sample. The procedure was atraumatic and did not cause hemolysis.


CONCLUSIONS
Particle separation by means of an acoustic standing-wave technique can be used for atraumatic and effective removal of lipid particles from blood, with the possible clinical implication of reducing neurocognitive complications after cardiopulmonary bypass.
Jönsson
Henrik
H
Department of Cardiothoracic Surgery, Center for Heart and Lung Disease, Lund University Hospital, Lund, Sweden. henrik.jonsson@thorax.lu.se
Holm
Cecilia
C
Nilsson
Andreas
A
Petersson
Filip
F
Johnsson
Per
P
Laurell
Thomas
T
D000818:Animals; D001018:Aortic Diseases / Q000150:complications*; D001161:Arteriosclerosis / Q000150:complications*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000295:instrumentation*; D002417:Cattle; D002469:Cell Separation / Q000295:instrumentation* / Q000379:methods; D003072:Cognition Disorders / Q000209:etiology / Q000517:prevention & control*; D017700:Embolism, Cholesterol / Q000209:etiology / Q000517:prevention & control*; D004867:Equipment Design; D004912:Erythrocytes; D006400:Hematocrit; D006801:Humans; D020766:Intracranial Embolism / Q000209:etiology / Q000517:prevention & control*; D007431:Intraoperative Complications / Q000209:etiology / Q000517:prevention & control*; D008055:Lipids / Q000097:blood; D044085:Microfluidics / Q000295:instrumentation*; D010316:Particle Size; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control*; D014159:Transducers; D014465:Ultrasonics
D008055:Lipids