Analysis of red cell transfusion practices in patients without active haemorrhage over a 12-month period in a UK intensive care unit

Introduction

The deleterious effects of red blood cell (RBC) transfusion are well known [1] and restrictive transfusion practices are safe in patients without active haemorrhage [2]. Our objective was to determine transfusion practices in critically ill patients without evidence of ongoing bleeding to establish our conformity with published guidelines [3].

Methods

All adult ICU patients receiving RBC transfusions between 1 September 2008 and 31 August 2009 were included in the analysis. Data were collected on demographics, APACHE II score, ICU and hospital length of stay (LOS), ICU and hospital mortality, presence of ischaemic heart disease (IHD), and pre/post-transfusion haemoglobin concentrations in g/dl ([Hb]). Subgroup analyses were performed for patients with IHD, age <55 years or APACHE II ≤20. We analysed patients with IHD because benefit from liberal transfusion has not been confirmed [1] whereas the latter two subgroups have shown a mortality benefit with restrictive transfusion [2].

Results

A total of 1,723 patients were admitted to the ICU during the study period. Two hundred and five patients (11.9%) received RBCs, of whom 47 had active bleeding and were excluded from further analysis. The remaining 158 patients (9.2%) received a total of 477 units RBCs (median 2.0 units/patient, IQR 1.0 to 3.8). Median pre-transfusion [Hb] was 7.7 (IQR 7.3 to 8.2) with a post-transfusion [Hb] of 9.2(IQR 8.5 to 9.8). Median ICU and hospital LOS in days was 10.9 (IQR 4.9 to 18.8) and 26.9 (IQR 14.0 to 45.0). ICU and hospital mortalities were 34.2% and 44.9%, respectively. Patients with acute IHD had a pre-transfusion [Hb] of 8.3(IQR 7.8 to 8.8) with a post-transfusion [Hb] of 9.4 (IQR 9.2 to 10.2) whilst patients with chronic IHD had values of 7.9 (IQR 7.4 to 8.4) and 9.4 (IQR 8.5 to 9.8), respectively. In patients aged <55 years, pre/post-transfusion values were 7.5 (IQR 7.1 to 8.0) and 9.2 (IQR 8.5 to 10.0), respectively, and patients with APACHE II ≤20 had values of 7.7 (IQR 7.3 to 8.2) and 9.2 (IQR 8.5 to 9.8), respectively.

Conclusions

[Hb] transfusion triggers were >7 in all subgroups and post-transfusion [Hb] was >9. Transfusion strategies were too liberal. It is important to restrict transfusions to limit morbidity and mortality and to make efficient use of RBCs [4]. This study demonstrates the importance of regular audit and will be used to inform local guidelines.