Iatrogenic Anemia in the ICU
Anh Nguyen, MD, MPH, PGY2
Background





Patients who were admitted to the ICU need to have a lot of
blood tests related to their illness and for further treatment.
However, that can cause decrease Hgb/Hct or iatrogenic
anemia.
Conflicting evidence of the association between anemia
among ICU patients and excessive diagnostic blood draws.
The increased laboratory use leads to increasing other costs
such as electrolyte repletion, blood transfusion (in patients
with anemia attributable to laboratory testing).
These higher costs did not have significant different ICU
lengths of stay or hospital mortality.
Methodology





Cross-sectional study, patient charts review
Inclusion criteria: ICU stay > 3 days
Exclusion criteria: ICU stay < 3 days, GI
bleed, trauma bleeding, pancytopenia,
pulmonary hemorrhage
Main variables: baseline Hgb/Hct, Hgb/Hct
when leave the ICU, length of stay in the ICU
Effect modification variable: Anemia of
chronic disease
Methodology



Reviewed 33 ICU charts
Included 15 charts in the study
Excluded 18 charts based on exclusion criteria
Analysis


Using SAS
Student t-tests
Results
Conclusion

This cross-sectional study showed that
iatrogenic blood loss for laboratory
investigation is one of the causes of anemia
in the ICU.

Physicians should only order phlebotomy for
necessary investigation and for the most
effective of diagnosis and treatment.
Discussion




Lack of evidence of benefit of the current practice of frequent
laboratory testing in the ICU.
Excessive costs, potential risks, and no proof of benefit which
mandates a re-evaluation of the current approach to routine
laboratory testing in the ICU
Unknown whether normalization of abnormal routine laboratory
values compared to reference range among patients in the ICU
confers net benefit.
In addition to correcting abnormal laboratory values, there is a
tendency to recheck laboratory tests after the intervention
Discussion



Risks associated with transfusion: transmission of
infectious agents, an increased risk of nosocomial
infections, transfusion-related acute lung injury,
transfusion-associated circulatory overload, and
transfusion-related graft-versus-host disease
Admission laboratory tests are valuable to establish
baseline values for comparisons with later values
Routine, undirected, daily laboratory evaluation (eg.
homeostatic laboratory testing) is a practice of
questionable utility, and efforts to reduce it are
warranted
Plan for Improving Current Practice




Small volume collection tubes
Transfuse to maintain Hgb 7-9 g/dL
Decrease the number of daily ABG’s, CMP’s,
and CBC’s if possible
Increase the intervals at which homeostatic
laboratory tests are obtained (decrease from
daily to every 3 days)
Plan for Improving Current Practice




The practice of bundling multiple lab tests together
(eg. BMP) should be abandoned
Laboratory testing should be pursued as a part of
therapeutic response to a clinical problem rather
than as a search for abnormal values to be
corrected.
Testing in the context of higher pretest probabilities
of disease should be emphasized
Train ICU house officers to be thoughtful in ordering
routine ICU laboratory tests during first-year
orientation
References




Ezzie ME, Aberegg SK, O’Brien JM. Laboratory testing in
the intensive care unit. Crit Care Clin 2007;23:435-465.
Shander A. Anemia in the critically ill. Crit Care Clin
2004;20(2):159-78
Tarpey J, Lawler PG. Iatrogenic anaemia? A survey of
venesection in patients in the intensive therapy unit.
Anaesthesia 1990;45(5)396-8.
Tosiri P, Kanitsap N, Kanitsap A. Approximate iatrogenic
blood loss in medical intensive care patients and the cause
of anemia. J Med Assoc Thai 2010;93(7):S271-6.