title: Particle separation using ultrasound can radically reduce embolic load to brain after cardiac surgery.
abstract: 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.
authors.affiliation: Department of Cardiothoracic Surgery, Center for Heart and Lung Disease, Lund University Hospital, Lund, Sweden. henrik.jonsson@thorax.lu.se
authors.forename: Henrik
authors.initials: H
authors.lastname: Jönsson
authors.forename: Cecilia
authors.initials: C
authors.lastname: Holm
authors.forename: Andreas
authors.initials: A
authors.lastname: Nilsson
authors.forename: Filip
authors.initials: F
authors.lastname: Petersson
authors.forename: Per
authors.initials: P
authors.lastname: Johnsson
authors.forename: Thomas
authors.initials: T
authors.lastname: Laurell
mesh_terms: 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
chemical_list: D008055:Lipids