Microcirculatory effects of the transfusion of leukodepleted or non-leukodepleted red blood cells in patients with sepsis: a pilot study

Abstract

IntroductionMicrovascular 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.MethodsIn 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.ResultsNo 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).ConclusionsThis 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.Trial registrationClinicalTrials.gov, NCT01584999

Characteristics and Determinants of the Sublingual Microcirculation in Populations of Different Ethnicity

“…The percentage capillary recruitment was assessed by dividing the increase of perfused capillary density after 4 minutes of arterial occlusion by the baseline value. 24 Imaging as implemented in our current or previous studies [6][7][8][9][10][11][12][13]25 does not capture the endothelial lining of the capillaries. The perfused boundary region is, therefore, an indirect estimate of glycocalyx width.…”

“…26 Moreover, compared with normal controls, type 1 diabetic patients had a thinner glycocalyx in sublingual capillaries, but higher levels of circulating hyaluronidase and hyaluronan, a principal glycocalyx constituent. 26 The current literature on the perfused boundary region, [6][7][8][9][10][11][12][13]25 from which the glycocalyx width is inferred by sidestream darkfield imaging, is limited to case-control studies with sample size ranging from 16 8 to 150. 12 All studies focused on the sublingual capillaries with the exception of 1 study of the peritubular microcirculation studied at the time of renal transplantation.…”

“…12 All studies focused on the sublingual capillaries with the exception of 1 study of the peritubular microcirculation studied at the time of renal transplantation. 13 Cases were patients with diabetes mellitus, 6,7 cardiovascular disease ,11,12 stroke, 25 end-stage renal disease, [8][9][10] or sepsis. 13 When compared with controls, the glycocalyx width estimated from the perfused boundary region was smaller in cases with type 2 diabetes mellitus 6,7 or end-stage renal disease.…”

“…13 Cases were patients with diabetes mellitus, 6,7 cardiovascular disease ,11,12 stroke, 25 end-stage renal disease, [8][9][10] or sepsis. 13 When compared with controls, the glycocalyx width estimated from the perfused boundary region was smaller in cases with type 2 diabetes mellitus 6,7 or end-stage renal disease. [8][9][10] Among patients with cardiovascular disease and matched controls, the results were contradictory, cases having a decreased 11 or similar 12 perfused boundary region.…”

“…Most studies published to date had a small sample size or a case-control design, including selected volunteers 5 or patients with diabetes mellitus, 6,7 renal dysfunction, [8][9][10] cardiovascular disease, 11,12 sepsis or critically ill patients. 13,14 To our knowledge, no previous population study focused on the sublingual microcirculation to assess capillary density and glycocalyx width. Our current study aimed to characterize these microcirculatory traits in relation Abstract-No previous population study assessed sublingual capillary density (CD) or perfused boundary region (PBR).…”