title: Ultrasound monitoring of RBC aggregation as a real-time marker of the inflammatory response in a cardiopulmonary bypass swine model.
abstract: OBJECTIVE
  In many pathological conditions, including high-risk surgery, the severity of the inflammatory response is related to the patient outcome. However, determining the patient inflammatory state presents difficulties, as markers are obtained intermittently through blood testing with long delay. RBC aggregation is a surrogate marker of inflammation that can be quantified with the ultrasound Structure Factor Size and Attenuation Estimator. The latter is proposed as a real-time inflammation monitoring technique for patient care.
  
  
  METHODS
  Ten swine underwent a 90-minute cardiopulmonary bypass, and surveillance was maintained during 120 minutes in the postbypass period. To promote the inflammatory reaction, lipopolysaccharide was administrated two times prior to surgery in six of those swine (lipopolysaccharide group). During the whole procedure, the Structure Factor Size and Attenuation Estimator cellular imaging method displayed a RBC aggregation index (W) computed from images acquired within the pump circuit and the femoral vein. Interleukin-6, interleukin-10, C-reactive protein, haptoglobin, immunoglobulin G, and fibrinogen concentrations were measured at specific periods.
  
  
  RESULTS
  Compared with controls, the lipopolysaccharide group exhibited higher W within the pump circuit (p < 0.05). In the femoral vein, W was gradually amplified in the lipopolysaccharide group during cardiopulmonary bypass and the postbypass period (p < 0.05), whereas interleukin levels were higher in the lipopolysaccharide group but only at the end of cardiopulmonary bypass and beginning of postbypass (p < 0.05).
  
  
  CONCLUSIONS
  Continuous RBC aggregation monitoring can characterize the evolving inflammatory response during and after cardiopulmonary bypass. The Structure Factor Size and Attenuation Estimator is proposed as a real-time noninvasive monitoring technique to anticipate inflammation-related complications during high-risk surgery or critical care situations. Because RBC aggregation promotes vascular resistance and thrombosis, W could also provide early information on vascular disorders in those clinical situations.
authors: Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center, Montreal, Quebec, Canada.
authors: Julien
authors: J
authors: Tripette
authors: André Y
authors: AY
authors: Denault
authors: Louise
authors: L
authors: Allard
authors: Boris
authors: B
authors: Chayer
authors: Louis P
authors: LP
authors: Perrault
authors: Guy
authors: G
authors: Cloutier
mesh_terms: D000818:Animals; D002097:C-Reactive Protein / Q000032:analysis; D002315:Cardiopulmonary Bypass; D004903:Erythrocyte Aggregation; D005268:Femoral Vein / Q000000981:diagnostic imaging*; D005340:Fibrinogen / Q000032:analysis; D007249:Inflammation / Q000097:blood; D007378:Interleukins / Q000097:blood; D008070:Lipopolysaccharides / Q000008:administration & dosage; D023421:Models, Animal; D013552:Swine; D014463:Ultrasonography
chemical_list: D007378:Interleukins; D008070:Lipopolysaccharides; D005340:Fibrinogen; D002097:C-Reactive Protein