BLOOD TRANSFUSION: WHEN TO TRANSFUSE AND RISKS INVOLVED

UC Irvine Internal Medicine

Mini-Lecture

Johnathan Zhang June 2013

OBJECTIVES

Understand when blood transfusion is indicated and not indicated.

Know the risks involved with blood transfusion.

CASE

A 67 y/o M w/ h/o CAD s/p CABG, CKD stage III, HTN, HLD, DM is admitted for fever, cough, and SOB. He is diagnosed with community acquired pneumonia. Hemoglobin at admission is 8.2. There is no evidence of active bleeding. At baseline the patient is able to climb 2 flights of stairs without SOB or CP. During hospitalization, the patient received multiple blood draws. After 4 days, Pt’s symptoms have improved. He is AF, HR is 70, BP 120/80, RR 20, 95% on RA. You are planning discharge today. Hemoglobin this morning is 7.3.

What is the best approach to managing this pt’s Anemia?

CASE

A) Transfuse 2 units PRBCB) Transfuse to goal Hg >10C) Recheck Hg/HctD) Discharge with outpatient follow-up

Blood transfusion is not indicated in this patient at this time. His anemia is asymptomatic. He has a h/o CAD but no e/o active ischemia. His Hg is likely not lab error given that he has been in the hospital for multiple days and has received numerous blood draws likely leading to phlebotomy associated anemia.

PURPOSE OF BLOOD TRANSFUSION

To increase oxygen delivery to tissues. DO2  =  cardiac output  x  arterial oxygen

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BACKGROUND

Carson et al. “Mortality and morbidity in patients with very low postoperative Hb levels who decline blood transfusion.” Transfusion 2002 Mortality

Hgb 7.1 to 8.0 (n = 99) — zero percent Hgb 5.1 to 7.0 (n = 110) — 9 percent Hgb 3.1 to 5.0 (n = 60) — 30 percent Hgb ≤3.0 (n = 31) — 64 percent

Viele MK, Weiskopf RB. “What can we learn about the need for transfusion from patients who refuse blood? The experience with Jehovah's Witnesses.” Transfusion 1994 Review of 61 case reports w/ Hg <8 or Hct <24 in

critically ill or post-surgery. 25 survivors reported Hg <5.

BACKGROUND

Hébert PC et al. “A multicenter, randomized, controlled clinical trial of transfusion requirements in critical care. Transfusion Requirements in Critical Care Investigators, Canadian Critical Care Trials Group.” NEJM 1999 838 Critically ill, euvolemic patients w/ 2 study

arms Liberal Transfusion – Goal Hg 10-12, Transfuse w/

Hg<10 Restrictive Transfusion – Goal Hg 7-9, Transfuse w/

Hg<7. No difference 30 day mortality In-hospital mortality lower for restrictive

transfusion (significant)

BACKGROUND

Carson et al. “Liberal versus restrictive transfusion thresholds for patients with symptomatic coronary artery disease” American Heart Journal June 2013 Pilot study 110 pts Transfusion to Hg >10 for pts with ACS compared

to transfusion for Hg <8 or symptomatic. “liberal transfusion” had trend toward greater 30

day survival (not statistically significant).

BACKGROUND

Villanueva et al. “Transfusion strategies for acute upper gastrointestinal bleeding.” NEJM Jan 2013. 2 Arms. Patients w/o significant comorbid

illnesses. Restrictive transfusion strategy: Tx only for Hg<7 Liberal transfusion strategy: Tx when Hg <9.

Patients receiving a restrictive transfusion strategy had significantly less rebleeding and adverse events.

Restrictive transfusion also w/ trend toward lower mortality for Peptic ulcer bleeding (not significant) and pt’s w/ Cirrhosis Child Pugh classes A and B (significantly less).

WHEN TO PULL THE “TRANSFUSION TRIGGER?”

Should not be based solely on hemoglobin number.

Decision should consider clinical scenario, patient characteristics, and symptoms.

WHEN TO PULL THE “TRANSFUSION TRIGGER?”

American Association of Blood Banks Guidelines Hgb <6 – Transfusion recommended Hgb 6-7 – Transfusion likely recommended Hgb 7-8 – Restrictive Transfusion Strategy for

stable patients (Strong recommendation). Consider transfusion only if post-operative or symptomatic (chest pain, orthostatic hypotension or tachycardia unresponsive to fluid resuscitation, or congestive heart failure).

Hgb 8 – 10 – TRANSFUSION GENERALLY NOT INDICATED Can consider Tx in special circumstances (ie ACS w/ active

ischemia, symptomatic anemia, active bleeding, critical ill septic shock with ScVO2<70).

Hgb >10 – TRANSFUSION NOT INDICATED

RISKS OF BLOOD TRANSFUSION

Transfusion-transmitted pathogens (HIV, HBV, HCV, CMV, bacteria, parasites)

Allergic and Immunologic Reactions Transfusion Associated Circulatory Overload

(TACO) Transfusion Related Acute Lung Injury (TRALI) Electrolyte abnormalities, hyperkalemia,

citrate toxicity (metabolic alkalosis or ionized hypocalcemia) Consider giving Calcium prophylactically with

massive transfusion

ORDERING TRANSFUSION

Try to order 1 unit at a time. Pre-medication w/ benadryl +/-

acetaminophen not supported by data. Infusion rate: 1-2ml/min x15 min then as

rapid as needed. No need to recheck Hg/Hct following

transfusion unless concerned for active bleeding or hemolysis.

CASE

74 y/o F w/ h/o peripheral vascular disease, aplastic anemia and MDS presents with progressive SOB, lightheadedness, and generalized weakness. Hemoglobin is 5.1. There is no evidence of bleeding. Patient is hemodynamically stable.

2U PRBC is ordered and begin running. After 1.5 U, the patient develops sudden shortness of breath and agitation. Wheezing is heard in bilateral lung fields. O2 sat is 80%. ABG shows pH 7.02, PCO2 70, PaO2 65 on 100% O2 non-rebreather. CXR as follows…

CXR EARLIER IN DAY

CXR W/ SUDDEN SOB.

WHAT IS THE MOST LIKELY DIAGNOSIS

A) Pulmonary EmbolismB) Transfusion Related Acute Lung InjuryC) Transfusion Associated Circulatory OverloadD) AnaphylaxisE) Acute Respiratory Distress Syndrome

More common than TRALI (1 in 100 vs 1 in 10,000). This case was confirmed to be TACO. PE usually causes respiratory alkalosis with hypoxia on ABG. Anaphylaxis should be considered but TACO is more likely in this scenario. ARDS is less likely given no evidence of infection or inflammation prior to the sudden event.

SUMMARY

Blood transfusion is not benign and should be ordered judiciously.

Most patients with chronic anemia can compensate oxygen delivery by increasing cardiac output.

Generally avoid transfusion for Hg>7 for most stable patients without active cardiovascular disease or active bleeding.

Fever and TACO are the most common complications occurring about 1 in 100 transfusions.

REFERENCES

Carson JL et al. Red blood cell transfusion: a clinical practice guideline from the AABB*. Ann Intern Med. 2012 Jul 3;157(1):49-58

Wang JK, Klein HG. Red blood cell transfusion in the treatment and management of anaemia: the search for the elusive transfusion trigger. Vox Sang. 2010 Jan;98(1):2-11.

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