title: Microcirculatory effects of the transfusion of leukodepleted or non-leukodepleted red blood cells in patients with sepsis: a pilot study.
abstract: BACKGROUND
  Microvascular alterations impair tissue oxygenation during sepsis. A red blood cell (RBC) transfusion increases oxygen (O2) delivery but rarely improves tissue O2 uptake in patients with sepsis. Possible causes include RBC alterations due to prolonged storage or residual leukocyte-derived inflammatory mediators. The aim of this study was to compare the effects of two types of transfused RBCs on microcirculation in patients with sepsis.
  
  
  METHODS
  In a prospective randomized trial, 20 patients with sepsis were divided into two separate groups and received either non-leukodepleted (n = 10) or leukodepleted (n = 10) RBC transfusions. Microvascular density and perfusion were assessed with sidestream dark field (SDF) imaging sublingually, before and 1 hour after transfusions. Thenar tissue O2 saturation (StO2) and tissue hemoglobin index (THI) were determined with near-infrared spectroscopy, and a vascular occlusion test was performed. The microcirculatory perfused boundary region was assessed in SDF images as an index of glycocalyx damage, and glycocalyx compounds (syndecan-1, hyaluronan, and heparan sulfate) were measured in the serum.
  
  
  RESULTS
  No differences were observed in microvascular parameters at baseline and after transfusion between the groups, except for the proportion of perfused vessels (PPV) and blood flow velocity, which were higher after transfusion in the leukodepleted group. Microvascular flow index in small vessels (MFI) and blood flow velocity exhibited different responses to transfusion between the two groups (P = 0.03 and P = 0.04, respectively), with a positive effect of leukodepleted RBCs. When within-group changes were examined, microcirculatory improvement was observed only in patients who received leukodepleted RBC transfusion as suggested by the increase in De Backer score (P = 0.02), perfused vessel density (P = 0.04), PPV (P = 0.01), and MFI (P = 0.04). Blood flow velocity decreased in the non-leukodepleted group (P = 0.03). THI and StO2 upslope increased in both groups. StO2 and StO2 downslope increased in patients who received non-leukodepleted RBC transfusions. Syndecan-1 increased after the transfusion of non-leukodepleted RBCs (P = 0.03).
  
  
  CONCLUSIONS
  This study does not show a clear superiority of leukodepleted over non-leukodepleted RBC transfusions on microvascular perfusion in patients with sepsis, although it suggests a more favorable effect of leukodepleted RBCs on microcirculatory convective flow. Further studies are needed to confirm these findings.
  
  
  BACKGROUND
  ClinicalTrials.gov, NCT01584999.
authors: Abele
authors: A
authors: Donati
authors: Elisa
authors: E
authors: Damiani
authors: Michele
authors: M
authors: Luchetti
authors: Roberta
authors: R
authors: Domizi
authors: Claudia
authors: C
authors: Scorcella
authors: Andrea
authors: A
authors: Carsetti
authors: Vincenzo
authors: V
authors: Gabbanelli
authors: Paola
authors: P
authors: Carletti
authors: Rosella
authors: R
authors: Bencivenga
authors: Hans
authors: H
authors: Vink
authors: Erica
authors: E
authors: Adrario
authors: Michael
authors: M
authors: Piagnerelli
authors: Armando
authors: A
authors: Gabrielli
authors: Paolo
authors: P
authors: Pelaia
authors: Can
authors: C
authors: Ince
mesh_terms: D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D017707:Erythrocyte Transfusion / Q000379:methods*; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D019276:Glycocalyx / Q000378:metabolism; D006801:Humans; D007962:Leukocytes; D008297:Male; D008833:Microcirculation / Q000502:physiology*; D008875:Middle Aged; D009060:Mouth Floor / Q000098:blood supply; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D010865:Pilot Projects; D011446:Prospective Studies; D018805:Sepsis / Q000378:metabolism / Q000503:physiopathology*; D019265:Spectroscopy, Near-Infrared; D016896:Treatment Outcome
chemical_list: D010100:Oxygen