Red blood cell transfusion affects microdialysis-assessed interstitial lactate/pyruvate ratio in critically ill patients with late sepsis.
OBJECTIVE
The aim of this study was to explore the effect of red blood cell (RBC) transfusion on microdialysis-assessed interstitial fluid metabolic parameters in septic patients.


METHODS
We conducted a retrospective study of 37 patients with severe sepsis/septic shock requiring transfusion of one to two RBC units. Interstitial fluid metabolic alterations were monitored by a microdialysis catheter inserted in the subcutaneous adipose tissue. Samples were collected before (T0) and after transfusion at two time-points: T1a and T1b; median post-transfusion times of 120 [interquartile range (IQR); 45-180] and 360 (IQR; 285-320) min. Lactate, pyruvate, glycerol and glucose concentrations were measured with a bedside analyzer, and the lactate/pyruvate (LP) ratio was calculated automatically.


RESULTS
RBC transfusions decreased the LP ratio from (T0) 18.80 [interquartile range (IQR); 14.85-27.45] to (T1a) 17.80 (IQR; 14.35-25.20; P < 0.05) and (T1b) 17.90 (IQR; 14.45-22.75; P < 0.001), while there was also significant interindividual variation. Post-transfusion LP ratio changes at T1a [r = -0.42; 95 % confidence interval (CI), -0.66 to -0.098; P = 0.01] and T1b (r = -0.68; 95 % [CI], -0.82 to -0.44; P < 0.001) were significantly correlated with the pre-transfusion LP ratio, but not with baseline demographic characteristics, vital signs, severity scores, hemoglobin level and blood lactate. RBC storage time and leukocyte reduction had no influence on the tissue metabolic response to transfusion.


CONCLUSIONS
Tissue oxygenation is affected by RBC transfusion in critically ill septic patients. Monitoring of tissue LP ratio by microdialysis may represent a useful method for individual clinical management.
Second Department of Critical Care Medicine, Attiko University Hospital, Medical School, National and Kapodistrian University of Athens, 1 Rimini Street, Haidari, 12462, Athens, Greece. petkop@ath.forthnet.gr
Petros
P
Kopterides
Maria
M
Theodorakopoulou
Nikitas
N
Nikitas
Ioannis
I
Ilias
Dimitra Argiro
DA
Vassiliadi
Stylianos E
SE
Orfanos
Iraklis
I
Tsangaris
Nikolaos A
NA
Maniatis
Argirios E
AE
Tsantes
Anthi
A
Travlou
George
G
Dimitriadis
Apostolos
A
Armaganidis
Urban
U
Ungerstedt
Ioanna
I
Dimopoulou
D000273:Adipose Tissue / Q000098:blood supply / Q000378:metabolism; D000368:Aged; D001800:Blood Specimen Collection / Q000379:methods; D017707:Erythrocyte Transfusion; D045604:Extracellular Fluid / Q000737:chemistry; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000378:metabolism / Q000628:therapy*; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D008833:Microcirculation; D017551:Microdialysis; D008875:Middle Aged; D015999:Multivariate Analysis; D010084:Oxidation-Reduction; D010865:Pilot Projects; D019095:Point-of-Care Systems; D019289:Pyruvic Acid / Q000378:metabolism; D012189:Retrospective Studies; D018805:Sepsis / Q000378:metabolism / Q000628:therapy*; D012772:Shock, Septic / Q000378:metabolism / Q000628:therapy; D013997:Time Factors
D019344:Lactic Acid; D019289:Pyruvic Acid