Interventions to prevent iatrogenic anemia: a Laboratory Medicine Best Practices systematic review

Nedra S Whitehead,Laurina O Williams,Julie Gayken,Michael T Mcevoy,Mark L Graber,Dennis J Ernst,Nneka Ubaka-Blackmoore,Jennifer Taylor,Sara M Kennedy,James H Nichols,Sharon M Geaghan,Paul Epner,Christine Litwin,Sreelatha Meleth,Patrick Carroll

doi:10.1186/s13054-019-2511-9

Abstract

BackgroundAs many as 90% of patients develop anemia by their third day in an intensive care unit (ICU). We evaluated the efficacy of interventions to reduce phlebotomy-related blood loss on the volume of blood lost, hemoglobin levels, transfusions, and incidence of anemia.MethodsWe conducted a systematic review and meta-analysis using the Laboratory Medicine Best Practices (LMBP) systematic review methods for rating study quality and assessing the body of evidence. Searches of PubMed, Embase, Cochrane, Web of Science, PsychINFO, and CINAHL identified 2564 published references. We included studies of the impact of interventions to reduce phlebotomy-related blood loss on blood loss, hemoglobin levels, transfusions, or anemia among hospital inpatients. We excluded studies not published in English and studies that did not have a comparison group, did not report an outcome of interest, or were rated as poor quality. Twenty-one studies met these criteria. We conducted a meta-analysis if > 2 homogenous studies reported sufficient information for analysis.ResultsWe found moderate, consistent evidence that devices that return blood from flushing venous or arterial lines to the patient reduced blood loss by approximately 25% in both neonatal ICU (NICU) and adult ICU patients [pooled estimate in adults, 24.7 (95% CI = 12.1–37.3)]. Bundled interventions that included blood conservation devices appeared to reduce blood loss by at least 25% (suggestive evidence). The evidence was insufficient to determine if these devices reduced hemoglobin decline or risk of anemia. The evidence suggested that small volume tubes reduced the risk of anemia, but was insufficient to determine if they affected the volume of blood loss or the rate of hemoglobin decline.ConclusionsModerate, consistent evidence indicated that devices that return blood from testing or flushing lines to the patient reduce the volume of blood loss by approximately 25% among ICU patients. The results of this systematic review support the use of blood conservation systems with arterial or venous catheters to eliminate blood waste when drawing blood for testing. The evidence was insufficient to conclude the devices impacted hemoglobin levels or transfusion rates. The use of small volume tubes may reduce the risk of anemia.

Highlights

As many as 90% of patients develop anemia by their third day in an intensive care unit (ICU)
We examined the impact of interventions to reduce blood loss from diagnostic testing on the volume of blood lost, decline in hemoglobin, incidence of anemia, and transfusion rate
Consistent evidence that blood conservation devices that return blood to the patient from flushing of venous or arterial lines or from in-line testing reduce the volume of blood loss by approximately 25%; relative reduction in blood loss was the same in neonatal ICU (NICU) and adult ICU patients

Summary

Introduction

As many as 90% of patients develop anemia by their third day in an intensive care unit (ICU). Adult intensive care unit (ICU) patients lose approximately 340–660 mL of blood per week to diagnostic testing [1, 2], with an 18% increase in the risk of anemia for each 50 mL of blood lost [3]. Over 70% of adult ICU patients are anemic by the second day of admission, and almost half will be transfused [4]. A recent cohort study of small volume tubes [6] found that they reduced the total volume of blood drawn per patient per day, but samples with fibrin present and total laboratory errors increased significantly (fibrin 0.3%, p < 0.001; total errors, 0.4%, p = 0.03)

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