title: Blood transfusions in septic shock: is 7.0 g/dL really the appropriate threshold?
abstract: OBJECTIVE
  To evaluate the immediate effects of red blood cell transfusion on central venous oxygen saturation and lactate levels in septic shock patients with different transfusion triggers.
  
  
  METHODS
  We included patients with a diagnosis of septic shock within the last 48 hours and hemoglobin levels below 9.0 g/dL Patients were randomized for immediate transfusion with hemoglobin concentrations maintained above 9.0 g/dL (Group Hb9) or to withhold transfusion unless hemoglobin felt bellow 7.0 g/dL (Group Hb7). Hemoglobin, lactate, central venous oxygen saturation levels were determined before and one hour after each transfusion.
  
  
  RESULTS
  We included 46 patients and 74 transfusions. Patients in Group Hb7 had a significant reduction in median lactate from 2.44 (2.00 - 3.22) mMol/L to 2.21 (1.80 - 2.79) mMol/L, p = 0.005, which was not observed in Group Hb9 [1.90 (1.80 - 2.65) mMol/L to 2.00 (1.70 - 2.41) mMol/L, p = 0.23]. Central venous oxygen saturation levels increased in Group Hb7 [68.0 (64.0 - 72.0)% to 72.0 (69.0 - 75.0)%, p < 0.0001] but not in Group Hb9 [72.0 (69.0 - 74.0)% to 72.0 (71.0 - 73.0)%, p = 0.98]. Patients with elevated lactate or central venous oxygen saturation < 70% at baseline had a significant increase in these variables, regardless of baseline hemoglobin levels. Patients with normal values did not show a decrease in either group.
  
  
  CONCLUSIONS
  Red blood cell transfusion increased central venous oxygen saturation and decreased lactate levels in patients with hypoperfusion regardless of their baseline hemoglobin levels. Transfusion did not appear to impair these variables in patients without hypoperfusion. ClinicalTrials.gov NCT01611753.
authors.affiliation: Departamento de Anestesiologia, Dor e Terapia Intensiva, Universidade Federal de São Paulo, São Paulo, SP, Brasil.
authors.forename: Bruno Franco
authors.initials: BF
authors.lastname: Mazza
authors.affiliation: Departamento de Anestesiologia, Dor e Terapia Intensiva, Universidade Federal de São Paulo, São Paulo, SP, Brasil.
authors.forename: Flavio Geraldo Rezende
authors.initials: FG
authors.lastname: Freitas
authors.affiliation: Departamento de Hematologia, Universidade Federal de São Paulo, São Paulo, SP, Brasil.
authors.forename: Melca Maria Oliveira
authors.initials: MM
authors.lastname: Barros
authors.affiliation: Departamento de Anestesiologia, Dor e Terapia Intensiva, Universidade Federal de São Paulo, São Paulo, SP, Brasil.
authors.forename: Luciano Cesar Pontes
authors.initials: LC
authors.lastname: Azevedo
authors.affiliation: Departamento de Anestesiologia, Dor e Terapia Intensiva, Universidade Federal de São Paulo, São Paulo, SP, Brasil.
authors.forename: Flavia Ribeiro
authors.initials: FR
authors.lastname: Machado
mesh_terms: D017707:Erythrocyte Transfusion / Q000379:methods*; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D011446:Prospective Studies; D012772:Shock, Septic / Q000097:blood / Q000628:therapy*
chemical_list: D006454:Hemoglobins; D019344:Lactic Acid; D010100:Oxygen