title: Determination of tissue hypoxia by physicochemical approach in premature anemia.
abstract: Anemia is a common problem in premature infants and its most rapid and effective therapy is erythrocyte transfusion. However, owing to inherent risks of transfusion in this population, transfusions should be administered only when adequate oxygen delivery to tissues is impaired. The aim of this study was to determine tissue acid levels using Stewart method in an attempt to evaluate the tissue oxygenation level and thereby the accuracy of transfusion timing.
  
  
  
  This study included 47 infants delivered at gestational age below 34 weeks who required erythrocyte transfusion for premature anemia. Strong ion gap (SIG), unmeasurable anions (UMA), tissue acid levels (TA), and Cl/Na ratios were calculated before and after transfusion.
  
  
  
  The mean birth weight and gestational age of the study population were 1210 ± 365 g and 29.2 ± 2.7 weeks, respectively. Tissue acid levels were increased (TA ≥ 4) and tissue hypoxia developed in 10 (16.6%) of 60 erythrocyte transfusions administered according to the restrictive transfusion approach. The patients were divided into two groups according to tissue acid levels as low (<4) and high (≥4) tissue acid groups. The group with tissue hypoxia (TA ≥ 4) had significantly higher UMA levels but a significantly lower Cl/Na ratio; and UMA levels decreased and Cl/Na ratio increased after transfusion in this group. Tissue hypoxia secondary to anemia was shown to be improved by erythrocyte transfusion.
  
  
  
  The results of the present study suggest that the determination of the level of tissue hypoxia by the Stewart approach may be an alternative to restrictive transfusion guidelines for timing of transfusion in premature anemia. It also showed that a low Cl/Na ratio can be used as a simple marker of tissue hypoxia.
authors.affiliation: Baskent University Faculty of Medicine, Department of Neonatology, Seyhan, Adana, Turkey.
authors.forename: Zeliha
authors.initials: Z
authors.lastname: Özdemir
authors.affiliation: Baskent University Faculty of Medicine, Department of Neonatology, Seyhan, Adana, Turkey. Electronic address: b.torer@yahoo.com.
authors.forename: Birgin
authors.initials: B
authors.lastname: Törer
authors.affiliation: Baskent University Faculty of Medicine, Department of Neonatology, Seyhan, Adana, Turkey.
authors.forename: Deniz
authors.initials: D
authors.lastname: Hanta
authors.affiliation: Baskent University Faculty of Medicine, Department of Neonatology, Seyhan, Adana, Turkey.
authors.forename: Bilin
authors.initials: B
authors.lastname: Cetinkaya
authors.affiliation: Baskent University Faculty of Medicine, Department of Neonatology, Seyhan, Adana, Turkey.
authors.forename: Hande
authors.initials: H
authors.lastname: Gulcan
authors.affiliation: Baskent University Faculty of Medicine, Department of Neonatology, Seyhan, Adana, Turkey.
authors.forename: Aylin
authors.initials: A
authors.lastname: Tarcan
mesh_terms: D000740:Anemia / Q000175:diagnosis* / Q000378:metabolism; D015415:Biomarkers / Q000097:blood; D017707:Erythrocyte Transfusion; D005260:Female; D005865:Gestational Age; D006801:Humans; D000860:Hypoxia / Q000175:diagnosis* / Q000378:metabolism; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000175:diagnosis* / Q000378:metabolism; D008297:Male
chemical_list: D015415:Biomarkers
keywords: Stewart method; anemia; premature; tissue hypoxia; transfusion