Pulmonary transfusion reactions: Clinical sciences

Chapters:

Watch video only

Introduction0:00–1:08

A pulmonary transfusion reaction refers to an acute lung injury within 6 hours of a blood product transfusion that results in pulmonary edema and respiratory distress.
Now, based on the underlying mechanism, there are two main types of pulmonary transfusion reactions! The first one is a nonimmunologic reaction called transfusion-associated circulatory overload, or TACO for short.
TACO occurs due to volume overload and subsequent increase in hydrostatic pressure that eventually leads to cardiogenic pulmonary edema.
The second type refers to an immune-mediated reaction called transfusion-related acute lung injury, or TRALI for short. In TRALI, the donor’s blood products usually contain anti-leukocyte antibodies that bind the recipient leukocytes and cause an inflammatory reaction.
This ultimately results in endothelial damage, capillary leakage, and eventually noncardiogenic pulmonary edema, often also associated with fever and hypotension.Okay, if a patient presents with a chief concern suggesting a pulmonary transfusion reaction, first, you should perform an ABCDE assessment to determine if they are unstable or stable.

Unstable patient1:08–2:26

If unstable, stabilize the airway, breathing, and circulation and stop transfusion! If your patient is hypotensive, start intravenous fluids for volume resuscitation and consider vasopressors.
Next, provide supplemental oxygen to maintain oxygen saturation. In severe cases, you might need to intubate the patient and put them on mechanical ventilation.
Finally, put your patient on continuous vital sign monitoring including blood pressure, heart rate, and pulse oximetry, as well as cardiac telemetry.
Here’s a clinical pearl to keep in mind! Unstable patients with rapidly progressive dyspnea and bilateral pulmonary edema have a wide differential diagnosis.
While a recent blood product transfusion may point you in the direction of a pulmonary transfusion reaction, be sure to consider similar clinical presentations, such as acute respiratory distress syndrome, pneumonia, or cardiac conditions, like congestive heart failure.Now, let’s return to the ABCDE assessment and take a look at stable patients.

Stable Patient2:26–3:22

In this case, obtain a focused history and physical exam and check the patient’s saturation using pulse oximetry. Your patient will typically report shortness of breath within 6 hours of blood product transfusion.
Additionally, the physical exam will reveal tachycardia and signs of respiratory distress, such as tachypnea, dyspnea, and respiratory rales, while the pulse oximetry will show a drop in oxygen saturation, usually below 90%!
Now, here’s a clinical pearl! If the patient is already on a mechanical ventilator, they may have difficulty communicating their shortness of breath.
Instead, you might observe oxygen desaturation and frothy secretions collecting in the endotracheal tube.With these findings, you should suspect a pulmonary transfusion reaction, so your next step is to order additional labs including CBC, and BNP.

Suspect Pulmonary Transfusion Reactions3:22–3:42

You should also order imaging studies, including chest x-ray and echocardiogram; and a 12-lead ECG.Alright, let’s start with TACO!
In this case, history will typically reveal risk factors associated with TACO, such as older age and chronic cardiovascular, renal, or pulmonary conditions.

TACO3:42–5:16

Next, the physical exam will reveal signs of fluid overload! These include hypertension, jugular venous distention, peripheral edema, as well as S3 gallop!
Additionally, since there’s fluid overload, the patient’s body weight will increase! Next, since TACO is a non-immune mediated reaction, CBC will show no signs of immunologic reaction, so, usually, there will be no leukopenia and thrombocytopenia.
But, since there’s fluid overload and ventricles are getting overstretched, you will find elevated BNP levels! Now, let’s take a look at imaging!
The chest X-ray will reveal signs of fluid overload, such as enlarged cardiac silhouette, but also signs of cardiogenic pulmonary edema, including Kerley B lines, bilateral pulmonary infiltrates, and peribronchial cuffing.
In some cases, you might even notice pleural fluid! Additionally, the echocardiogram will show signs of left ventricular dysfunction, while the ECG will reveal no signs of acute myocardial ischemia or infarction!
With these findings, you can diagnose TACO, so immediately proceed with management, which primarily relies on supportive measures and diuresis.

TACO Management5:16–6:03

First, stop the transfusion, provide supplemental oxygen, and if necessary, initiate more aggressive respiratory support, like mechanical ventilation.
Finally, don’t forget to administer diuretics to address the circulatory overload.Here’s a clinical pearl to keep in mind!
When you diagnose a pulmonary transfusion reaction, do not use the donor blood any further and inform the blood bank immediately!
If you need more blood products for transfusion, you should use a different donor! Okay, now let’s switch gears and discuss TRALI.

TRALI6:03–7:31

In this case, history might reveal risk factors associated with TRALI, such as direct or indirect lung injury due to conditions like pneumonia or severe sepsis.
Additionally, almost always your patient will present with elevated body temperature, and can also present with hypoxemia and tachycardia.
But, unlike in TACO, in these individuals, there will be no signs of fluid overload. In other words, these patients will present with hypotension and absence of jugular venous distention, peripheral edema, S3 gallop, and weight changes.
However, in contrast to TACO, TRALI is an immune-mediated reaction, so labs will typically reveal leukopenia and thrombocytopenia!
And since there’s no fluid overload and no myocardial ischemia and infarction, BNP and cardiac enzymes will be normal.Now, let’s take a look at imaging.
The chest X-ray will show signs of noncardiogenic pulmonary edema, like bilateral pulmonary infiltrates. Keep in mind that in these individuals, you’re not going to identify pleural fluid.
Additionally, the echocardiogram will show no signs of ventricular dysfunction, while the ECG will reveal no signs of myocardial ischemia and infarction.
At this point, you can diagnose TRALI, so immediately proceed with management, which primarily relies on supportive care!

TRALI Management7:31–9:28

This includes stopping the transfusion and providing supplemental oxygen. If necessary, initiate more aggressive respiratory support with mechanical ventilation.
In contrast to TACO, individuals with TRALI do not require diuretics since there is no fluid overload, but you can consider intravenous fluids to address hypotension.Here are several clinical pearls!
You can further differentiate between TACO and TRALI by obtaining leukocyte antibodies, which are typically found in TRALI and not TACO!
Additionally, you can check levels of posttransfusion cytokines to differentiate the two. For example, high interleukin-6 levels are common for both TRALI and TACO.
However, elevated interleukin-8 is seen in patients with TRALI only. Finally, remember, the incidence of TRALI has substantially decreased by using donated blood products from male-only, HLA antibody-negative, and nulliparous female donors.
Be sure to screen blood donors at higher risk of causing TRALI, such as donors with history of pregnancy or previous transfusions.
Using leukocyte reduced blood products can significantly reduce risk of TRALI.And here’s one last high-yield fact! TACO and TRALI are pulmonary transfusion reactions, but some individuals can also develop an anaphylactic transfusion reaction!
In this case, your patient will present with urticarial rash, hypotension, wheezing due to bronchospasm, respiratory distress, and even shock!
Alright, as a quick recap… TACO and TRALI are pulmonary transfusion reactions characterized by respiratory distress, occurring within 6 hours of a blood product transfusion.

Review9:28–10:33

If you suspect a pulmonary transfusion reaction, order additional labs and imaging methods to determine the type of reaction.
Individuals who develop TACO typically present with acute dyspnea and signs of volume overload, such as hypertension, jugular venous distention, peripheral edema, as well as S3 gallop!
Additionally, in this case, labs will reveal elevated BNP levels due to myocardial stretching. On the flip side, in TRALI, the patient will present with acute dyspnea without fluid overload.
Instead, these patients most commonly present with fever and hypotension! Additionally, labs will reveal leukopenia, thrombocytopenia, and normal BNP levels.
Finally, in both conditions, the chest X-ray will show bilateral pulmonary