Labs

The following is the patient’s complete blood count (CBC):

What’s what: WBC, white blood cell count; Hb, hemoglobin; MCV, mean cell volume; MCHC, mean cellular hemoglobin concentration; RDW, red cell distribution width; platelets, PLT; Normal values: WBC 5-10 x 10⁹/L, RBC 4-6 x 10¹²/L, Hb 12-16 g/dL, Hct 35-47%, MCV 80-100 fL, MCHC 32-36 g/dL, RDW-SD < 45%, platelets (PLT) 150-450 x 10⁹/L

How would you describe the CBC?

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Normocytic, hypochromic anemia

The following are the patient’s coags:

What’s what: PT, prothrombin time; INR, international ratio; aPTT, activated partial thromboplastin time; Normal values: PT 9.4-12.5 seconds, aPTT 25-36.5 seconds.

How would you interpret these coagulation assays?

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Normal

Question 1: Based on the information provided, what is appropriate for this patient:

Explanation to question 1:

Indications for transfusion are based on most current guidelines.¹ Red blood cell (RBC) transfusion is indicated for symptomatic deficiency of O₂-carrying capacity or tissue hypoxia due to inadequate circulating RBC mass (anemia). When deciding whether to transfuse an individual patient, it is important to consider the clinical context, current hemoglobin (Hb) level (trigger or threshold), patient preferences and alternative therapies to transfusion:

• For hemodynamically stable hospitalized adult patients, including critically ill patients, a restrictive RBC transfusion practice is recommended with transfusion not being indicated until the Hb level is below 7 g/dL.
• For patients undergoing orthopedic surgery, cardiac surgery, and those with preexisting cardiovascular disease a transfusion threshold of 8 g/dL is recommended.

Therefore, as this patient is undergoing orthopedic surgery and has a Hb level below 8 g/dL, RBC transfusion is indicated.²

As far as the dosage, for a clinically stable patient, such as this one, RBCs are transfused one at a time and the response is monitored. However, in deciding how much to transfuse, other critical factors include:

• Shortness of breath
• Exercise (in)tolerance
• Lightheadedness
• Chest pain thought to be cardiac in origin
• Hypotension or tachycardia unresponsive to fluid challenge
• Rate of decline in Hb level
• Intravascular volume status.

Question 2: What is the expected response to transfusion of one RBC unit:

Explanation to question 2:

The expected increase in hemoglobin (Hb) and hematocrit (Hct) levels in adult patients after one red blood cell (RBC) transfusion are 1 g/dL and 3%, respectively. If the patient experiences symptoms, also expected and desirable is their remission, however, this may be dependent on other dynamics, not just anemia correction.

Answer 2 is not correct; an appropriate response should be a post-transfusion Hct of 28%.

Answer 4 is not correct obviously, Hb/Hct should not decrease after RBC transfusion. If this happens, DO NOT further transfuse with RBC without understanding why the expected response is not observed and CONSIDER other causes for acute blood loss, including hyperhemolysis. Hyperhemolysis is a serious transfusion reaction characterized by destruction of both donor and host RBCs and reported mostly in association with sickle cell disease, but also other conditions. A high index of caution should be exerted when a patient is suspected to have hyperhemolysis because RBC transfusions are contraindicated despite the Hb drop. In fact, further transfusions may accentuate the hemolysis potentially leading to patient’s demise. This is a condition that should be quickly recognized and treated.

Question 3: When are the RBC transfusions NOT indicated (more than one answer may apply):

Explanation to question 3:

All answers are correct. They each represent a contraindication to red blood cell (RBC) transfusions. In acute blood loss of <20-30% of total blood volume, infusion of crystalloids is often adequate. RBC should not be used for correction of nutritional anemias as volume expanders or to improve wound healing or enhance a patient’s subjective sense of well-being.

Question 4: How should the RBC be administered and patient monitored (more than one answer may apply):

Explanation to question 4:

RBC transfusions are administered at a rate of 2-5 mL/min as tolerated in non-bleeding patients via 23-gauge needle or larger (18 gauge preferred) and using standard size filter (170-260 mm).

Answer 2 is not correct. In a hemodynamically stable patient, the minimum and maximum time to transfuse is 1 and 4 hours, respectively. In general, transfusion time and rates vary according to the clinical context. High volumes and rates of transfusion may lead to transfusion-associated circulatory overload (TACO), an underrecognized but potentially fatal adverse reaction.

Answer 3 is incomplete. Vital signs should be measured pre-transfusion, within 15 minutes of start, and post-transfusion. The 15-minute vital sign measurement is very important because changes may indicate an acute hemolytic transfusion reactions (AHTR), another transfusion reaction type that is potentially fatal.

Answer 4 is correct. RBC transfusion can be administered with 0.9 sodium chloride injection, USP, through the same tubing at the same time. RBCs should NEVER be administered with lactated Ringer’s solution (contains high levels of calcium that may overcome the citrate anticoagulant in the bag), dextrose (cause RBC swelling), and/or any medications (can cause hemolysis). Other acceptable fluids that can be administered with the RBCs are 5% albumin and ABO-compatible plasma. Certain solutions, such as Normosol-R pH 7.4 (Hospira), Plasma-Lyte-A injection pH 7.4 and Plasma-Lyte 148 injection (Baxter Healthcare) which are isotonic and do not contain calcium are compatible with administration of blood and blood components. The hospital administration protocol should specify the types of compatible fluids.