# Transfusion-Related Acute Lung Injury

TRALI is acute, noncardiogenic pulmonary edema beginning during or within 6 hours of transfusion. Immediate transfusion cessation, respiratory support, exclusion of circulatory overload, and transfusion-service reporting are the critical decisions; diuresis is not indicated unless concurrent TACO is present.

**Clinical question:** How should clinicians recognize, distinguish, stabilize, and investigate suspected transfusion-related acute lung injury?

Updated: 2026-08-24T16:50:01.202609+00:00

## What matters in practice
- Classify new hypoxemia or respiratory compromise that begins during or within 6 hours of transfusion with bilateral pulmonary edema as suspected TRALI only after assessing for substantial left atrial hypertension and competing ARDS causes. [6][10][14]
- Stop the transfusion, maintain the IV line as needed, provide oxygen or ventilatory support according to hypoxemia severity, and notify the transfusion service promptly. [9][13][23]
- TRALI type II requires an ARDS risk factor or mild ARDS but stable respiratory status during the 12 hours before transfusion; worsening pretransfusion respiratory status favors ARDS rather than TRALI type II. [6][10]
- TACO can coexist with TRALI. Volume-overload features support TACO and warrant diuresis, whereas routine diuretics may worsen intravascular depletion in isolated TRALI. [13][15][23]
- Report every suspected pulmonary transfusion reaction to the transfusion service because donor investigation and product restriction may prevent recurrent donor-associated reactions. [7][23][24]

## Respond to New Hypoxemia During or After Transfusion

Treat acute respiratory deterioration temporally linked to transfusion as a transfusion reaction until proven otherwise.

Immediately stop the transfusion when dyspnea, hypoxemia, hypotension, fever, or new pulmonary edema develops during infusion or within 6 hours after completion. Maintain access as clinically necessary, increase oxygen delivery, obtain a portable chest radiograph when respiratory status worsens, and notify the transfusion service. [10][20][23]

Stabilize oxygenation before assigning a reaction subtype. Use supplemental oxygen for less severe hypoxemia; provide mechanical ventilatory support when oxygenation or work of breathing requires it. TRALI management is supportive and parallels management of permeability pulmonary edema; low-pressure, low-tidal-volume ventilation is described to reduce ventilator-associated barotrauma risk. [9][13][23]

Do not administer empiric diuretics solely because the radiograph shows edema. Diuretics may reduce intravascular volume in TRALI and are not indicated for isolated permeability edema; reserve respiratory support plus diuresis for a clinical picture supporting TACO or a mixed TRALI-TACO process. [13][23]
- Document the onset of respiratory compromise or hypoxemia relative to transfusion completion; the diagnostic window is 6 hours. [6][10]
- Obtain chest imaging to identify bilateral pulmonary edema; imaging and assessment for left atrial hypertension may be documented up to 24 hours after onset. [10]
- Review every component administered during a multiple-transfusion episode; massive transfusion does not exclude TRALI. [12]

*Immediate decisions in acute pulmonary deterioration associated with transfusion. [9][10][13][20][23]*

| Finding or action | Interpretation | Next step |
| --- | --- | --- |
| Respiratory compromise or hypoxemia during or within 6 hours after transfusion | Meets the required temporal window for TRALI assessment. [6][10] | Stop transfusion, support oxygenation, obtain chest imaging, and notify the transfusion service. [10][20][23] |
| Bilateral pulmonary edema with no substantial left atrial hypertension | Supports noncardiogenic edema and possible TRALI after competing causes are assessed. [10][14] | Manage as permeability edema; avoid routine diuresis in isolated TRALI. [13] |
| Clinical volume overload or cardiac dysfunction | Favors TACO; TRALI and TACO may coexist. [15][23] | Treat overload with respiratory support and diuresis while completing transfusion-reaction evaluation. [23] |
| Pulmonary edema first recognized more than 6 hours after transfusion | Do not classify as TRALI under the consensus definition; classify as transfusion-associated dyspnea when temporally suspicious. [10] | Evaluate alternative pulmonary and cardiac causes and report the reaction. [10][23] |

## Classify TRALI Type I, TRALI Type II, or ARDS

The distinction hinges on timing, objective pulmonary edema, left atrial hypertension, and the pretransfusion respiratory trajectory.

Diagnose TRALI clinically rather than by a single confirmatory assay. The core syndrome is acute hypoxemia with bilateral pulmonary edema during or within 6 hours of transfusion, without substantial left atrial hypertension. Hypoxemia may be defined by a PaO2/FiO2 ratio of 300 or less or oxygen saturation below 90% on room air. [10][14]

Classify TRALI type I when the patient fulfills posttransfusion pulmonary edema criteria and has no ARDS risk factor. Sepsis, pneumonia, aspiration, shock, and similar acute lung-injury risks must trigger a competing ARDS assessment rather than automatic type I classification. [6][14][21]

Classify TRALI type II only when an ARDS risk factor or mild ARDS is present, the posttransfusion event otherwise meets type I criteria, and pulmonary status was stable during the preceding 12 hours, including stability assessed by PaO2/FiO2 ratio. A declining oxygenation trajectory before transfusion instead supports ARDS progression. [6][10]

Do not require a pulmonary artery wedge pressure measurement or PEEP above 5 cm H2O to make the diagnosis. In contemporary practice, assess for left atrial hypertension using clinical evidence and available cardiac or volume-status data; BNP alone has uncertain ability to distinguish ARDS from cardiogenic edema. [10][12][4]
- Use the onset of hypoxemia or respiratory compromise—not delayed completion of all testing—to anchor the 6-hour interval. [10]
- Document whether bilateral opacities represent pulmonary edema and whether left atrial hypertension is absent or not the principal explanation. [10]
- Transient leukopenia, fever, and hypotension can support the clinical impression but are not required diagnostic criteria. [2][5][11]

### When an ARDS Risk Factor Is Present

A patient with sepsis, aspiration, pneumonia, or shock who is stable for 12 hours before transfusion but develops abrupt pulmonary edema and hypoxemia within 6 hours may have TRALI type II. A patient whose respiratory function was worsening before transfusion should be classified as ARDS rather than TRALI type II, even if transfusion preceded further deterioration. [6][10][14]

*Consensus-oriented classification of posttransfusion pulmonary edema. [6][10][14][21]*

| Classification | Required clinical pattern | Discriminator |
| --- | --- | --- |
| TRALI type I | Acute hypoxemia and bilateral pulmonary edema during or within 6 hours of transfusion, without substantial left atrial hypertension and without an ARDS risk factor. [10][14][21] | No competing acute lung-injury risk factor. [14][21] |
| TRALI type II | Meets type I pulmonary criteria, occurs with an ARDS risk factor or mild ARDS, and respiratory status was stable during the prior 12 hours. [6][10] | Stable pretransfusion PaO2/FiO2 or equivalent pulmonary status. [6] |
| ARDS | Pulmonary edema and hypoxemia occur in the presence of an ARDS risk factor with worsening respiratory status before transfusion. [6][10] | Pretransfusion deterioration outweighs temporal association alone. [6][10] |
| Transfusion-associated dyspnea | Pulmonary edema occurs more than 6 hours after transfusion but remains clinically suspicious for temporal association. [10] | Outside the TRALI time window. [10] |

## Distinguish TRALI From TACO, Anaphylaxis, Sepsis, and Other Acute Lung Injury

The immediate therapeutic consequence of the differential is whether intravascular volume removal is helpful or harmful.

Prioritize TACO when pulmonary edema follows a large-volume or rapid infusion in a patient with left ventricular dysfunction, renal impairment, positive fluid balance, severe anemia, or advanced age. Orthopnea, hypertension, peripheral edema, cardiomegaly, and clinical volume overload favor TACO; respiratory support and diuresis are the principal therapeutic interventions. [23][24]

Favor TRALI when the dominant pattern is abrupt, profound hypoxemia with bilateral infiltrates, fever, hypotension, and no convincing pulmonary vascular overload. Both syndromes can occur simultaneously, so a patient with partial volume overload features should not be excluded from TRALI evaluation or donor investigation. [5][15][23]

Evaluate anaphylaxis when respiratory distress occurs with an acute allergic phenotype; acute hemolytic and febrile nonhemolytic reactions remain competing transfusion reactions. Evaluate sepsis, aspiration, pneumonia, and shock as alternative ARDS drivers, particularly when the patient had respiratory compromise before transfusion. [15][20][14]
- Do not use BNP as a stand-alone rule-in or rule-out test for TRALI versus cardiogenic edema; its discriminative ability in ARDS versus cardiogenic pulmonary edema is unclear. [4]
- Plasma, apheresis platelets, and whole blood carry higher TRALI risk because of larger plasma exposure, but TRALI has been reported after all blood components, including red cells, cryoprecipitate, granulocytes, IVIG, and stem-cell products. [15][22]
- In patients with a mixed phenotype, treat the hemodynamically supported overload component while preserving the TRALI workup and providing respiratory support. [15][23]

*Actionable comparison of TRALI and TACO in posttransfusion pulmonary edema. [5][13][15][23][24]*

| Feature | TRALI | TACO |
| --- | --- | --- |
| Timing | Usually develops during or within 6 hours after transfusion. [6][10] | Occurs after transfusion-associated volume loading; rapid or large-volume infusion is a risk context. [23][24] |
| Hemodynamics and examination | Hypotension and fever are common; pulmonary vascular overload is not the principal cause. [5][14] | Hypertension, orthopnea, peripheral edema, and risk factors for impaired volume handling support the diagnosis. [23][24] |
| Imaging | Bilateral diffuse pulmonary infiltrates from noncardiogenic edema. [5][14] | Pulmonary edema may occur with cardiomegaly. [24] |
| Treatment implication | Oxygenation and ventilatory support; routine diuretics are not indicated. [9][13] | Respiratory support plus diuresis. [23] |

## Provide Supportive Care and Reassess the Diagnosis

No targeted reversal therapy is established; management is driven by oxygenation, ventilation, and reassessment for volume overload or competing ARDS.

Supportive respiratory care is the treatment for TRALI. Escalate from supplemental oxygen to mechanical ventilation when hypoxemia or respiratory distress warrants it, and use ventilator pressures and tidal volumes intended to avoid barotrauma. [9][13][23]

Monitor serial oxygen requirement, pulse oximetry, hemodynamics, fluid balance, and chest imaging as clinically indicated. Most patients described in clinical summaries recover within 48 to 96 hours; persistent or worsening pulmonary failure should prompt renewed evaluation for ARDS, sepsis, aspiration, cardiac dysfunction, or a mixed reaction. [23][24]

Avoid interpreting a response to diuresis as definitive proof of TACO. Because TRALI and TACO may coexist, reassess volume status and oxygenation after interventions rather than forcing a single diagnosis in a patient with discordant findings. [15][23]
- Use mechanical ventilation when required for oxygenation; a plateau pressure above 30 cm H2O has been associated with higher mortality in ARDS and is also associated with TRALI risk in ventilated patients. [6]
- Do not delay transfusion-service notification until donor or recipient antibody testing is available; TRALI is a clinical diagnosis. [7][14]
- Escalate suspected TRALI in critically ill patients because ICU populations have historically had higher active-surveillance rates than general transfused populations. [11][22]

*Monitoring priorities after suspected TRALI. [6][9][13][23][24]*

| Domain | What to follow | Decision triggered |
| --- | --- | --- |
| Oxygenation | Oxygen requirement, pulse oximetry, and PaO2/FiO2 when arterial blood gases are available. [6][14] | Escalate oxygen or ventilatory support for worsening gas exchange. [9][23] |
| Ventilation | Ventilator pressures and tidal-volume strategy in intubated patients. [13] | Limit injurious ventilatory pressures; plateau pressure above 30 cm H2O is associated with worse ARDS outcomes. [6] |
| Volume and cardiac status | Fluid balance and clinical evidence of cardiac dysfunction or pulmonary vascular overload. [10][23] | Use diuresis when TACO or a mixed volume-overload component is supported. [23] |
| Clinical course | Trend respiratory failure over 48 to 96 hours. [23][24] | Failure to improve should trigger reassessment for alternative or concurrent causes of acute lung injury. [15][23] |

## Report Suspected TRALI and Reduce Future Exposure

The transfusion-service investigation protects future recipients and informs product selection.

Report all suspected pulmonary transfusion reactions to the transfusion service promptly. Potential TRALI reactions warrant donor investigation because donor blood products may cause additional cases; blood centers can contact and evaluate implicated donors. [7][23][24]

Donor-derived HLA class I, HLA class II, and HNA antibodies are major mechanisms, although TRALI can occur without detectable HLA or HNA antibodies. Consequently, absence of an identified antibody should not overturn a clinically appropriate TRALI classification. [8][7][19]

Risk-reduction strategies target plasma exposure and donor alloimmunization. Plasma from previously pregnant donors has been associated with TRALI risk, and male-only plasma was associated with a 68% reduction in TRALI risk across transfused units from 2006 to 2009. Solvent-detergent plasma has been reported to eliminate TRALI risk. [19][22]

For future transfusions, communicate the prior reaction to the transfusion service and reassess the indication for each component. A prior recipient episode does not itself establish heightened susceptibility to another TRALI episode when the original event was caused by antibodies in a specific donor product, but implicated donor products require restriction. [15][23]
- Consider every administered component in the investigation; plasma-rich products have higher risk, but red cells and other components can cause TRALI. [15][22]
- Do not exclude TRALI after massive transfusion; review separate transfusion events and products. [12]
- Critical illness, smoking, chronic alcohol use, high positive fluid balance, and elevated ventilatory pressures are described recipient or treatment-associated risk contexts. [6][11]

*Prevention and investigation actions after suspected TRALI. [7][12][15][19][22][23][24]*

| Action | Rationale | Operational implication |
| --- | --- | --- |
| Notify transfusion service | TRALI requires clinical reaction evaluation and may identify an implicated donor. [7][23] | Document timing, components, oxygenation, imaging, and evidence for or against volume overload. [10][23] |
| Investigate implicated donor and product | Donor leukocyte antibodies can mediate TRALI, and donor products may cause further reactions. [7][8][24] | Coordinate donor evaluation and restriction through the blood center or transfusion service. [7][24] |
| Use donor-mitigation strategies for plasma products | Pregnancy-related donor alloimmunization increases risk; male-only plasma reduced risk by 68% in a reported interval. [19][22] | Follow institutional component-selection policies for plasma and platelet products. [15][19] |
| Reassess future transfusion necessity | Total number of blood products is a transfusion-specific risk factor. [22] | Use only clinically indicated components and communicate the prior reaction before subsequent transfusion. [15][22] |

## References
1. TACO and TRALI: visualising transfusion lung injury on ... — casereports.bmj.com — https://casereports.bmj.com/content/bmjcr/13/4/e230426.full.pdf
2. Convalescent plasma for COVID-19 complicated by ARDS ... — casereports.bmj.com — https://casereports.bmj.com/content/14/1/e239762
3. Transfusion-related acute lung injury (TRALI) following intravenous immunoglobulin infusion in a patient with myasthenia gravis - ScienceDirect — www.sciencedirect.com — https://www.sciencedirect.com/science/article/abs/pii/S0006497125094340
4. Noncardiogenic Lung Edema - an overview | ScienceDirect Topics — www.sciencedirect.com — https://www.sciencedirect.com/topics/nursing-and-health-professions/noncardiogenic-lung-edema
5. Transfusion Related Acute Lung Injury - an overview — www.sciencedirect.com — https://www.sciencedirect.com/topics/medicine-and-dentistry/transfusion-related-acute-lung-injury
6. A consensus redefinition of transfusion‐related acute lung injury - Vlaar - 2019 - Transfusion - Wiley Online Library — onlinelibrary.wiley.com — https://onlinelibrary.wiley.com/doi/10.1111/trf.15311
7. Pathology Consultation on Transfusion-Related Acute Lung ... — academic.oup.com — https://academic.oup.com/ajcp/article/138/4/498/1760541
8. Pathology Consultation on Transfusion-Related Acute ... — academic.oup.com — https://academic.oup.com/ajcp/article-pdf/138/4/498/24992926/ajcpath138-0498.pdf
9. Transfusion-Related Acute Lung Injury — www.sciencedirect.com — https://www.sciencedirect.com/science/article/abs/pii/S0025619611615310
10. A consensus redefinition of transfusion‐related acute lung injury — pmc.ncbi.nlm.nih.gov — https://pmc.ncbi.nlm.nih.gov/articles/PMC6850655
11. Transfusion-Related Acute Lung Injury (TRALI): A Clinical Review with Emphasis on the Critically Ill — pmc.ncbi.nlm.nih.gov — https://pmc.ncbi.nlm.nih.gov/articles/PMC4532338
12. Risk factors, management and prevention of transfusion-related acute lung injury: a comprehensive update — pmc.ncbi.nlm.nih.gov — https://pmc.ncbi.nlm.nih.gov/articles/PMC6715498
13. Transfusion-related acute lung injury (TRALI): Current Concepts and Misconceptions — pmc.ncbi.nlm.nih.gov — https://pmc.ncbi.nlm.nih.gov/articles/PMC3134874
14. Transfusion-Related Acute Lung Injury - StatPearls - NCBI Bookshelf — www.ncbi.nlm.nih.gov — https://www.ncbi.nlm.nih.gov/books/NBK507846
15. Approach to the Diagnosis and Management of Transfusion-Related Acute Lung Injury | The Hematologist | American Society of Hematology — ashpublications.org — https://ashpublications.org/thehematologist/article/doi/10.1182/hem.V10.4.1046/462510/Approach-to-the-Diagnosis-and-Management-of
16. "Possible TRALI" developed during bilateral total knee arthroplasty replacement -A case report- - PMC — www.ncbi.nlm.nih.gov — https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3272533
17. Transfusion-related acute lung injury (TRALI) following intravenous immunoglobulin infusion in a patient with myasthenia gravis | Blood | American Society of Hematology — ashpublications.org — https://ashpublications.org/blood/article/146/Supplement%201/6687/550386/Transfusion-related-acute-lung-injury-TRALI
18. Two Cases of Transfusion-related Acute Lung Injury Triggered by HLA and Anti-HLA Antibody Reaction - PMC — www.ncbi.nlm.nih.gov — https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2923780
19. Spotlight on pathogenesis of TRALI: HNA-3a (CTL2) antibodies | Blood | American Society of Hematology — ashpublications.org — https://ashpublications.org/blood/article/124/12/1868/33023/Spotlight-on-pathogenesis-of-TRALI-HNA-3a-CTL2
20. Version 4.0 Serial #0002 1 06/19/2020 Study Protocol and ... — cdn.clinicaltrials.gov — https://cdn.clinicaltrials.gov/large-docs/72/NCT04502472/Prot_SAP_002.pdf
21. How I diagnose and treat cardiorespiratory complications of ... — ashpublications.org — https://ashpublications.org/blood/article/145/20/2283/518086/How-I-diagnose-and-treat-cardiorespiratory
22. TACO and TRALI: biology, risk factors, and prevention strategies - PMC — www.ncbi.nlm.nih.gov — https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6324877
23. Acute Hemolytic Transfusion Reaction - an overview — www.sciencedirect.com — https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/acute-hemolytic-transfusion-reaction
24. Blood Group Incompatibility - an overview — www.sciencedirect.com — https://www.sciencedirect.com/topics/immunology-and-microbiology/blood-group-incompatibility

## Editorial note

Prepared from cited clinical literature using Astra's research workflow. Verify recommendations against current guidance and patient-specific factors.