title: Exchange transfusion therapy and its effects on real-time microcirculation in pediatric sickle cell anemia patients: an intravital microscopy study.
abstract: Periodic blood exchange transfusion is a treatment modality commonly used to manage pediatric sickle cell anemia at the University of California Davis Medical Center. The goal of exchange transfusion therapy is to ameliorate vasoocclusion and improve tissue perfusion by removing sickled red blood cells and introducing normal red blood cells. Using computer-assisted intravital microscopy, pretransfusion and posttransfusion microvascular characteristics were analyzed. In this study, the bulbar conjunctiva exhibited a "blanched" avascular appearance in all 6 pediatric sickle cell anemia patients before transfusion, indicative of tissue hypoperfusion and ischemia. Immediately after transfusion, substantial improvement in vascularization and tissue perfusion resulted, reflected by the enhanced appearance of capillaries and arterioles. In addition, a decrease in red cell velocity was observed. These observations provide evidence that exchange transfusion therapy is beneficial in ameliorating vasoocclusion and improving tissue perfusion. However, with the paradoxical posttransfusion decrease in red cell velocity presumably due to induced hyperviscosity from the large transfusion volume, blood flow is still impaired. This decreased velocity may thwart efforts to improve oxygen delivery through transfusion and may, to some extent, promote vasoocclusion instead. This paradoxical result warrants further investigation on the effects of transfusion volume and viscosity in the exchange transfusion process.
authors.affiliation: Department of Medical Pathology, University of California, Davis, CA, USA. anthony.cheung@ucdmc.ucdavis.edu
authors.forename: Anthony T W
authors.initials: AT
authors.lastname: Cheung
authors.forename: Joshua W
authors.initials: JW
authors.lastname: Miller
authors.forename: Maricel G
authors.initials: MG
authors.lastname: Miguelino
authors.forename: Wilson J
authors.initials: WJ
authors.lastname: To
authors.forename: Jiajing
authors.initials: J
authors.lastname: Li
authors.forename: Xin
authors.initials: X
authors.lastname: Lin
authors.forename: Peter C
authors.initials: PC
authors.lastname: Chen
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Samarron
authors.forename: Ted
authors.initials: T
authors.lastname: Wun
authors.forename: Theodore
authors.initials: T
authors.lastname: Zwerdling
authors.forename: Ralph
authors.initials: R
authors.lastname: Green
mesh_terms: D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000097:blood* / Q000628:therapy*; D002648:Child; D002675:Child, Preschool; D005078:Exchange Transfusion, Whole Blood; D006801:Humans; D008137:Longitudinal Studies; D008833:Microcirculation; D018715:Microscopy, Video; D011379:Prognosis