ScvO 2 changes after red-blood-cell transfusion for anaemia in cardiothoracic and vascular ICU patients: an observational study

Vox Sang. 2018 Feb;113(2):136-142. doi: 10.1111/vox.12610. Epub 2017 Oct 29.


Background and objectives: Haemoglobin threshold for transfusion has been significantly decreased, but haemoglobin plasma concentration may not be sufficient to assess the need of red-blood-cell (RBC) transfusion. Central venous oxygen saturation (ScvO2 ) is a clue of metabolic matching between O2 transport and consumption, which could help to assess when transfusion is appropriate once anaemia has been diagnosed in ICU patients.

Materials and methods: Adult patients admitted consecutively to a cardiothoracic and vascular ICU were included in a prospective, observational and single-centre study over a 6-month period (September 2014 to February 2015), provided they were transfused with RBC. Patients with active bleeding or in unstable condition were excluded. Haemoglobin and ScvO2 were collected through a central venous catheter before and after transfusion. In order to identify a ScvO2 threshold, analysis of ScvO2 changes after transfusion was performed.

Results: Fifty-three patients received 100 RBC transfusions. Haemoglobin at the time of transfusion was 7·2 g/dl [6·8-7·7], while ScvO2 was 66·9% [60-73]. A 5% increase in ScvO2 after transfusion has the best specificity and positive predictive values, with a ScvO2 threshold of 65%. After transfusion (RBC units, 2 [1-2]), ScvO2 increased only in patients with ScvO2 ≤65%, from 58% [53-62] to 69% [64-73] (P < 0·001).

Conclusion: In anaemic patients, RBC transfusion induced a significant increase in ScvO2 , provided it was low before transfusion. A 65% cut-off value of ScvO2 before transfusion showed good specificity and good positive predictive value for a 5% increase after transfusion.

Keywords: ICU; ScvO2; anaemia; transfusion.

Publication types

  • Observational Study

MeSH terms

  • Aged
  • Anemia / therapy*
  • Critical Care / methods*
  • Erythrocyte Transfusion / adverse effects
  • Erythrocyte Transfusion / methods*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Oxygen / blood*
  • Oxyhemoglobins / metabolism


  • Oxyhemoglobins
  • Oxygen