title: Decreased erythrocyte deformability after transfusion and the effects of erythrocyte storage duration.
abstract: BACKGROUND
  Erythrocyte cell membranes undergo morphologic changes during storage, but it is unclear whether these changes are reversible. We assessed erythrocyte cell membrane deformability in patients before and after transfusion to determine the effects of storage duration and whether changes in deformability are reversible after transfusion.
  
  
  METHODS
  Sixteen patients undergoing posterior spinal fusion surgery were studied. Erythrocyte deformability was compared between those who required moderate transfusion (≥ 5 units erythrocytes) and those who received minimal transfusion (0-4 units erythrocytes). Deformability was measured in samples drawn directly from the blood storage bags before transfusion and in samples drawn from patients before and after transfusion (over 3 postoperative days). In samples taken from the blood storage bags, we compared deformability of erythrocytes stored for a long duration (≥ 21 days), those stored for a shorter duration (<21 days), and cell-salvaged erythrocytes. Deformability was assessed quantitatively using the elongation index (EI) measured by ektacytometry, a method that determines the ability for the cell to elongate when exposed to shear stress.
  
  
  RESULTS
  Erythrocyte deformability was significantly decreased from the preoperative baseline in patients after moderate transfusion (EI decreased by 12% ± 4% to 20% ± 6%; P = 0.03) but not after minimal transfusion (EI decreased by 3% ± 1% to 4% ± 1%; P = 0.68). These changes did not reverse over 3 postoperative days. Deformability was significantly less in erythrocytes stored for ≥ 21 days (EI = 0.28 ± 0.02) than in those stored for <21 days (EI = 0.33 ± 0.02; P = 0.001) or those drawn from patients preoperatively (EI = 0.33 ± 0.02; P = 0.001). Cell-salvaged erythrocytes had intermediate deformability (EI = 0.30 ± 0.03) that was greater than that of erythrocytes stored ≥ 21 days (P = 0.047), but less than that of erythrocytes stored <21 days (P = 0.03).
  
  
  CONCLUSIONS
  The findings demonstrate that increased duration of erythrocyte storage is associated with decreased cell membrane deformability and that these changes are not readily reversible after transfusion.
authors: From the Departments of Anesthesiology/Critical Care Medicine, Surgery, Division of Cardiac Surgery, Orthopedic Surgery, Anesthesiology/Critical Care Medicine and Biomedical Engineering, and Pathology, The Johns Hopkins Medical Institutions, Baltimore, Maryland.
authors: Steven M
authors: SM
authors: Frank
authors: Bagrat
authors: B
authors: Abazyan
authors: Masahiro
authors: M
authors: Ono
authors: Charles W
authors: CW
authors: Hogue
authors: David B
authors: DB
authors: Cohen
authors: Dan E
authors: DE
authors: Berkowitz
authors: Paul M
authors: PM
authors: Ness
authors: Viachaslau M
authors: VM
authors: Barodka
mesh_terms: D000328:Adult; D000368:Aged; D001793:Blood Preservation; D001803:Blood Transfusion; D003627:Data Interpretation, Statistical; D004907:Erythrocyte Deformability / Q000502:physiology*; D004910:Erythrocyte Membrane / Q000502:physiology; D017707:Erythrocyte Transfusion; D004912:Erythrocytes / Q000502:physiology / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D057725:Operative Blood Salvage; D013123:Spinal Fusion; D013997:Time Factors