Plasma free hemoglobin and microcirculatory response to fresh or old blood transfusions in sepsis.
BACKGROUND
Free hemoglobin (fHb) may induce vasoconstriction by scavenging nitric oxide. It may increase in older blood units due to storage lesions. This study evaluated whether old red blood cell transfusion increases plasma fHb in sepsis and how the microvascular response may be affected.


METHODS
This is a secondary analysis of a randomized study. Twenty adult septic patients received either fresh or old (<10 or >15 days storage, respectively) RBC transfusions. fHb was measured in RBC units and in the plasma before and 1 hour after transfusion. Simultaneously, the sublingual microcirculation was assessed with sidestream-dark field imaging. The perfused boundary region was calculated as an index of glycocalyx damage. Tissue oxygen saturation (StO2) and Hb index (THI) were measured with near-infrared spectroscopy and a vascular occlusion test was performed.


RESULTS
Similar fHb levels were found in the supernatant of fresh and old RBC units. Despite this, plasma fHb increased in the old RBC group after transfusion (from 0.125 [0.098-0.219] mg/mL to 0.238 [0.163-0.369] mg/mL, p = 0.006). The sublingual microcirculation was unaltered in both groups, while THI increased. The change in plasma fHb was inversely correlated with the changes in total vessel density (r = -0.57 [95% confidence interval -0.82, -0.16], p = 0.008), De Backer score (r = -0.63 [95% confidence interval -0.84, -0.25], p = 0.003) and THI (r = -0.72 [95% confidence interval -0.88, -0.39], p = 0.0003).


CONCLUSIONS
Old RBC transfusion was associated with an increase in plasma fHb in septic patients. Increasing plasma fHb levels were associated with decreased microvascular density.


BACKGROUND
ClinicalTrials.gov NCT01584999.
Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, Torrette di Ancona, Italy.
Elisa
E
Damiani
Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, Torrette di Ancona, Italy; Anesthesia and Intensive Care Unit, Azienda Ospedaliera Universitaria "Ospedali Riuniti", Torrette di Ancona, Italy.
Erica
E
Adrario
Department of Clinical and Molecular Sciences, Clinica Medica, Università Politecnica delle Marche, Torrette di Ancona, Italy.
Michele Maria
MM
Luchetti
Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, Torrette di Ancona, Italy.
Claudia
C
Scorcella
Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, Torrette di Ancona, Italy.
Andrea
A
Carsetti
Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, Torrette di Ancona, Italy.
Nicoletta
N
Mininno
Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, Torrette di Ancona, Italy.
Silvia
S
Pierantozzi
Anesthesia and Intensive Care Unit, Azienda Ospedaliera Universitaria "Ospedali Riuniti", Torrette di Ancona, Italy.
Tiziana
T
Principi
Anesthesia and Intensive Care Unit, Azienda Ospedaliera Universitaria "Ospedali Riuniti", Torrette di Ancona, Italy.
Daniele
D
Strovegli
Immunohematology and Transfusional Medicine, AOU Ospedali Riuniti, Torrette di Ancona, Italy.
Rosella
R
Bencivenga
Department of Clinical and Molecular Sciences, Clinica Medica, Università Politecnica delle Marche, Torrette di Ancona, Italy.
Armando
A
Gabrielli
Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, Torrette di Ancona, Italy.
Rocco
R
Romano
Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, Torrette di Ancona, Italy; Anesthesia and Intensive Care Unit, Azienda Ospedaliera Universitaria "Ospedali Riuniti", Torrette di Ancona, Italy.
Paolo
P
Pelaia
Department of Translational Physiology, Academic Medical Center, Amsterdam, The Netherlands.
Can
C
Ince
Department of Biomedical Sciences and Public Health, Università Politecnica delle Marche, Torrette di Ancona, Italy; Anesthesia and Intensive Care Unit, Azienda Ospedaliera Universitaria "Ospedali Riuniti", Torrette di Ancona, Italy; Department of Translational Physiology, Academic Medical Center, Amsterdam, The Netherlands.
Abele
A
Donati
D000368:Aged; D001803:Blood Transfusion; D005260:Female; D006439:Hemodynamics; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008297:Male; D008833:Microcirculation; D055806:Microvessels / Q000378:metabolism; D008875:Middle Aged; D011659:Pulmonary Gas Exchange; D018805:Sepsis / Q000097:blood* / Q000503:physiopathology / Q000628:therapy*
D006454:Hemoglobins