Spotlight Case

Transfusion Overload

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Source and Credits• This presentation is based on the November 2012

AHRQ WebM&M Spotlight Case– See the full article at http://webmm.ahrq.gov – CME credit is available

• Commentary by: Manish S. Patel, MD, and Jeffrey L. Carson, MD, of UMDNJ−Robert Wood Johnson Medical School– Editor, AHRQ WebM&M: Robert Wachter, MD– Spotlight Editor: Bradley A. Sharpe, MD– Managing Editor: Erin Hartman, MS

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ObjectivesAt the conclusion of this educational activity, participants should be able to:

• Understand that the traditional transfusion thresholds of hemoglobin below 10 g/dL and hematocrit below 30% are not supported by evidence

• List common serious adverse effects of transfusion• Describe evidence supporting a more restrictive

transfusion strategy• State the transfusion threshold that should be used in

hospitalized patients with and without coronary artery disease

Case: Transfusion Overload

A 77-year-old woman with chronic myelodysplastic syndrome (a disorder of the bone marrow leading to chronic anemia) underwent an uncomplicated coronary artery bypass grafting procedure for coronary artery disease. Two months later, she presented to the hospital with shortness of breath and was found to have mild congestive heart failure (CHF). An echocardiogram revealed mildly reduced left ventricular function. She was given diuretics and discharged to a skilled nursing facility (SNF) for rehabilitation.

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Case: Transfusion Overload (2)

At the SNF, a follow-up CBC showed a hemoglobin level of 7.1 g/dL (normal 12–16 g/dL). Of note, her baseline hemoglobin was between 8 g/dL and 10 g/dL. At the time, the patient remained weak but had no new symptoms. She also had no evidence of gastrointestinal or other bleeding. Her oncologist (who was managing the myelodysplastic syndrome) received the report the following day and arranged for the patient to be transferred to the emergency department (ED) for evaluation and transfusion.

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Case: Transfusion Overload (3)

Upon arrival at the ED, the patient had no symptoms and had normal vital signs. Her physical examination was unchanged from prior examinations and revealed no source of bleeding. A repeat hemoglobin level in the ED was 8.1 g/dL.

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Background: Transfusion

• Deciding when to transfuse patients with anemia is a common dilemma

• For many decades, clinicians followed the "10/30" rule—using red cell transfusion to keep the hemoglobin level at 10 g/dL and hematocrit at 30%

• However, the "10/30" rule was based only on anecdotal evidence

7 See Notes for reference.

Background: Transfusion (2)

• The HIV epidemic in the 1980s brought an increasing concern about blood-borne infections spread through transfusion

• However, the optimal hemoglobin concentration at which to transfuse remained undefined

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Transfusion in This Patient

• Change in this patient's hemoglobin level may reflect lab variability

• She did not appear to be actively bleeding or acutely symptomatic from the anemia

• Not clear she would benefit from transfusion • Transfusion could put her at risk for

complications

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Transfusion & Cardiovascular Disease

• In a study of 1958 surgical patients, 30-day mortality was higher in patients with cardiovascular disease when hemoglobin level dropped below 10 g/dL

• It is unclear whether transfusion would (or could) impact this mortality

• In a trial of elderly patients with cardiovascular disease, patients transfused for a hemoglobin level of 10 g/dL experienced no apparent benefit compared with those transfused at 8 g/dL or for symptoms

10 See Notes for references.

Managing This Patient

• There was no indication for a transfusion• It would have been reasonable to have her

return to the nursing facility and recheck the hemoglobin level in 1−2 weeks or if she had a change in symptoms

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Case: Transfusion Overload (4)

The ED provider contacted the oncologist with the evaluation results, and the oncologist requested the patient be admitted to the hospital and transfused with 2 units of blood. He knew about her heart failure and stated that diuretics should be given between each of the units. The patient was given the blood and the diuretics. Thirty minutes after the second unit of blood finished transfusing, the patient became lethargic and was found to have new hypoxia with an oxygen saturation of 60% on room air.

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Case: Transfusion Overload (5)

She rapidly worsened and had a respiratory arrest; a code blue was called. She was successfully resuscitated and intubated and transferred to the ICU. A chest radiograph revealed vascular congestion and edema. The clinicians caring for her believed she developed hypoxic respiratory failure from acute volume overload in the setting of CHF or from transfusion-related acute lung injury (TRALI; an immune-related transfusion reaction that leads to pulmonary infiltrates and hypoxia 0−6 hours after transfusion).

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Case: Transfusion Overload (6)

A repeat hemoglobin level at the time was 11.7 g/dL. Because a normal response to a unit of blood is an increase in hemoglobin of 1.0 g/dL, the hemoglobin level of 8.1 g/dL might have been inaccurate. With supportive care and more diuretics, the patient's hypoxic respiratory failure improved and she was extubated a day later. She remained in the hospital for 2 more weeks recovering from the episode and was transferred back to the SNF.

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Over-Transfusion

• "Over-transfusion" can occur when there is evidence to justify withholding red blood cell transfusion and a transfusion is given anyway

• In our opinion, over-transfusion is common• Several studies have estimated the

proportion of inappropriate transfusion at 24%−75%

15 See Notes for reference.

Risks of Transfusion

• Infectious risks such as HIV and hepatitis C• Two common serious adverse effects of transfusion:

– TACO: transfusion-associated circulatory overload– TRALI: transfusion-associated acute lung injury

• This patient had risk factors for TACO including: advanced age, underlying cardiovascular disease, and left ventricular dysfunction

• Other risk factors include transfusion rate, cumulative transfusion volume, and a positive fluid balance

16 See Notes for references.

Transfusing Multiple Units

• It has been standard practice for physicians to always transfuse 2 units of blood rather than one at a time

• There is no clear reason for this practice• If this patient had gotten one unit and responded,

the clinicians may have avoided the second unit, which seems to have led to the respiratory arrest

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Optimal Transfusion Threshold: Evidence

• TRICC trial randomized 838 normovolemic ICU patients to a "restrictive" or "liberal" transfusion strategy– Restrictive: transfuse for hemoglobin level < 7 g/dL– Liberal: transfuse for hemoglobin level < 10 g/dL

• Trend toward lower 30-day mortality in restrictive group (18.7% vs. 23.3%)

• All other negative outcomes also were less common in restrictive group

18 See Notes for reference.

Optimal Transfusion Threshold: Evidence (2)

• FOCUS trial randomized 2016 patients undergoing hip fracture repair with a history of (or risk factors for) cardiovascular disease to a "restrictive" or "liberal" strategy– Restrictive: transfuse only for hemoglobin level < 8 g/dL

or symptoms of anemia– Liberal: transfuse to maintain hemoglobin level > 10 g/dL

• All outcomes were similar in the two groups including exercise tolerance, death, and acute coronary syndrome in the hospital

19 See Notes for reference.

Evidence-Based Transfusion Guidelines

• American Association of Blood Banks (AABB) recommends the following transfusion thresholds in hospitalized patients:– Adhere to restrictive strategy and transfuse at a hemoglobin

level of 7 g/dL (in ICU patients) and 8 g/dL (in surgical and medical patients)

– In patients with known cardiovascular disease, adhere to restrictive strategy (consider transfusion for hemoglobin level < 8 g/dL or symptoms of anemia related to coronary disease)

– AABB could not recommend for or against liberal or restrictive strategy in patients with acute coronary syndrome (myocardial infarction or unstable angina)

20 See Notes for reference.

Disseminating the Guidelines

• A systematic review of interventions to reduce inappropriate transfusions showed that the following are effective:– Individual/group feedback– Education– Audit with feedback– Audit with approval– New order form with criteria for transfusion

21 See Notes for reference.

Take-Home Points

• Although the blood supply in the United States has been shown to be safe, transfusion is not without risks.

• In stable, hospitalized patients, a restrictive transfusion strategy, using a hemoglobin concentration 7−8 g/dL or the presence of symptoms of anemia as transfusion thresholds, has been shown to be safe.

• A restrictive transfusion strategy may also be utilized in stable, hospitalized patients with cardiovascular disease.

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Take-Home Points (2)

• Transfusion should be considered at hemoglobin transfusion threshold but not necessarily administered. The decision to transfuse should be based on a thorough assessment of each patient's individual clinical circumstances and symptoms.

• The transfusion threshold in patients with acute coronary syndromes is unknown.

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