Transfusion practice in the intensive care unit: a 10-year analysis

Abstract

Background: Clinical guidelines recommend a restrictive transfusion strategy in nonhemorrhaging critically ill patients.

Study design and methods: We conducted a retrospective observational study of 3533 single-admission patients, without evidence of acute coronary syndromes, hemorrhage, or hemoglobinopathy admitted to the medical intensive care unit (MICU) of a large, academic medical center.

Results: MICU admission hemoglobin (Hb) level did not change significantly over the study period. The proportion of transfused patients decreased from 31.0% in 1997 to 1998 to 18.0% in 2006 to 2007 (p<0.001). Among patients receiving transfusion, the mean pretransfusion Hb level decreased over time from 7.9±1.3 to 7.3±1.3g/dL (p<0.001). These changes in practice were not accounted for by differences in patient characteristics. The mean nadir Hb level in nontransfused patients decreased from 11.2±2.2g/dL in 1997 to 1999 to 10.4±2.3g/dL in 2006 to 2007 (p<0.001). The mean number of units per patient transfused decreased during this time from 4.3±4.7 to 3.0±3.8 units (p<0.001). The proportion of transfused patients who were transfused at a Hb level of less than 7.0g/dL increased by an estimated absolute increment of 3.2% (95% CI, 2.1%-4.3%) per interval (p<0.001), and the proportion of single-unit transfusions during the first transfusion episode increased by 1.4% per interval (95% CI, 0.2 to 2.6%; p=0.03) from 40.2% in 1997 to 1998 to 53.1% in 2006 to 2007.

Conclusions: Between 1997 and 2007, important and sustained changes have occurred in our MICU physician transfusion practices, with overall reductions in the proportion of patients transfused, mean pretransfusion Hb level, and nadir Hb level in patients who were not transfused.

Conflict of interest statement

The authors declare that they have no conflicts of interest relevant to the manuscript submitted to TRANSFUSION.

© 2010 American Association of Blood Banks.

Figures

Figure 1. Enrollment of study participants

UMMC, University of Maryland Medical Center; MICU, Medical Intensive Care Unit; ICD-9-CM, International Classification of Diseases, 9th Revision, Clinical Modification; ACS, Acute Coronary Syndrome; Hgb, Hemoglobin

Figure 2. Percentage of patients transfused, by interval

Linear regression estimated a 1.1% absolute reduction in percentage of patients transfused per interval (95%CI: 0.6% to 1.6%, p

Figure 3. Proportion of patients transfused, by strata, by interval

The proportion of transfused patients decreased over time in all three hemoglobin strata. Linear regression estimated a −2.0% absolute reduction per interval in Hgb

Figure 4. Mean nadir hemoglobin and mean pre-transfusion hemoglobin by interval

In non-transfused patients, mean nadir hemoglobin decreased from 11.2±2.2 g/dL (1997–1998) to 10.4±2.3 g/dL (2006–2007), linear regression model estimated a −0.077 g/dL change in mean nadir hemoglobin per interval (95%CI: –0.106 g/dL to –0.047g/dL, p