Lesson of the week. Acute non-cardiogenic lung oedema after platelet transfusion

Transfusion-related acute lung injury

Transfusion-related acute lung injury is a clinical syndrome that occurs within 6 hours of transfusion. It is the leading cause of transfusion-related mortality. It presents with shortness of breath, acute pulmonary edema, fever, hypotension, or hypertension followed by hypotension. Treatment consists of respiratory support and fluid administration to support blood pressure. A majority of cases are associated with antibodies to white blood cells in the blood donor. Blood centers in the United States are currently taking measures to reduce the risk of transfusion-related acute lung injury from blood components.

Transfusion-Related Acute Lung Injury

Transfusion-related acute lung injury (TRALI) refers to a clinical syndrome of acute lung injury that occurs in a temporal relationship with the transfusion of blood products. Because of the difficulty in making its diagnosis, TRALI is often underreported. Three not necessarily mutually exclusive hypotheses have been described to explain its etiogenesis: antibody mediated, non-antibody mediated, and two hit mechanisms. Treatment is primarily supportive and includes supplemental oxygen. Diuretics are generally not indicated, as hypovolemia should be avoided. Compared with many other forms of acute lung injury, including the acute respiratory distress syndrome, TRALI is generally transient, reverses spontaneously, and carries a better prognosis. A variety of prevention strategies have been proposed, ranging from restrictive transfusion strategies to using plasma derived only from males.

Are multiple blood transfusions really a cause of acute respiratory distress syndrome?

BACKGROUND AND OBJECTIVES

Multiple blood transfusions are considered a common cause of acute respiratory distress syndrome (ARDS). We hypothesized that ARDS is more a consequence of ARDS risk factors (in particular circulatory shock) requiring transfusions than a result of the transfusions themselves.

METHODS

This retrospective study included 103 patients admitted during a 10-month period to an 858-bed university hospital who received multiple transfusions (more than six units of packed red blood cells in 24 h).

RESULTS

Ten patients developed ARDS; they were more commonly admitted with circulatory shock (36 (38.7%) vs. 8 (80%), P = 0.01), polytrauma (7 (7.5%) vs. 4 (40%), P = 0.01) or thoracic trauma (3 (3.2%) vs. 4 (40%), P = 0.01). The sequential organ-failure assessment (SOFA) score at admission was higher in patients who developed ARDS than in those who did not (9.0 +/- 3.1 vs. 5.6 +/- 3.4, P < 0.005). The total amount of transfusion in the first 24 h was 14.0 +/- 6.8 U in the ARDS patients and 10.6 +/- 7.3 U in the other patients (P = 0.17); the differences remained non-significant in the following days. During the first 24 h, patients who developed ARDS received more fresh frozen plasma than those who did not (21.8 +/- 10.6 U vs. 10.7 +/- 14.7 U, P = 0.02). Patients who developed ARDS had lower PaO2/FiO2 ratios (114 +/- 61 mmHg vs. 276 +/- 108 mmHg, P = 0.01), lower arterial pH (7.27 +/- 0.10 vs. 7.34 +/- 0.11, P = 0.06) and higher minute volume (10.6 +/- 2.8 L min(-1) vs. 7.9 +/- 1.8 L min(-1), P = 0.03) than patients without ARDS. Multivariable analysis retained thoracic trauma and hypoxaemia during the first 24 h (but not multiple transfusions) as independent risk factors for ARDS.

CONCLUSIONS

In this retrospective study, the development of ARDS in massively transfused patients was less related to poly-transfusion than to other factors related to circulatory shock, polytrauma or thoracic trauma. Thoracic trauma and a low PaO2 during the first 24 h were identified as independent risk factors for ARDS.

A prospective randomized trial of a prophylactic platelet transfusion trigger of 10 x 109 per L versus 30 x 109 per L in allogeneic hematopoietic progenitor cell transplant recipients

BACKGROUND

The impact of lowering the platelet (PLT) count threshold for prophylactic PLT transfusion on bleeding and PLT use in allogeneic hematopoietic progenitor cell (HPC) transplant recipients is a matter of debate.

STUDY DESIGN AND METHODS

In 166 patients, randomly assigned to receive prophylactic PLT transfusion at a trigger level less than 10 x 10(9) PLTs per L (T10; n = 79) or less than 30 x 10(9) per L (T30; n = 87), the number of PLT and red blood cell (RBC) transfusions given and the number of hemorrhagic events (WHO Grades 2-4) were recorded.

RESULTS

No significant differences were found between the two groups regarding the clinical outcome variables (i.e., bacteremia, engraftment, graft-vs.-host disease [GVHD], hospital stay, death, and survival) or in the median total number of RBC transfusions given. The incidence, in Group T10 18 percent (14/79) and in Group T30 15 percent (13/87), as well as the type of bleeding were comparable. No deaths were attributed to hemorrhages. The number of PLT units transfused, however, was significantly lower in Group T10 (median, 4; range, 0-32), than in Group T30 (median, 10; range, 0-48; p < 0.001). Apart from the trigger level, the day of engraftment, the presence of acute GVHD, or bacteremia also affected the number of PLT transfusions.

CONCLUSION

A prophylactic PLT transfusion trigger level of less than 10 x 10(9) PLTs per L instead of less than 30 x 10(9) PLTs per L in allogeneic HPC transplant recipients was found to be safe and resulted in a decreased use of PLTs.

Pulmonary injury from transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) can be a life-threatening complication of transfusion. In its severe form, it is clinically indistinguishable from acute respiratory distress syndrome. Symptoms typically begin within 4 hours of transfusion. TRALI has been reported after transfusion of all plasma-containing blood components. TRALI is associated with antibodies to white blood cells and biologically active lipids in trans-fused blood components.

Transfusion-related acute lung injury: a review

Transfusion-related acute lung injury (TRALI) is an underreported complication of transfusion therapy, and it is the third most common cause of transfusion-associated death. TRALI is defined as noncardiogenic pulmonary edema temporally related to transfusion therapy. The diagnosis of TRALI relies on excluding other diagnoses such as sepsis, volume overload, and cardiogenic pulmonary edema. Supportive diagnostic evidence includes identifying neutrophil or human leukocyte antigen (HLA) antibodies in the donor or recipient plasma. All plasma-containing blood products have been implicated in TRALI, with the majority of cases linked to whole blood, packed RBCs, platelets, and fresh-frozen plasma. The pathogenesis of TRALI may be explained by a "two-hit" hypothesis, with the first "hit" being a predisposing inflammatory condition commonly present in the operating room or ICU. The second hit may involve the passive transfer of neutrophil or HLA antibodies from the donor or the transfusion of biologically active lipids from older, cellular blood products. Treatment is supportive, with a prognosis substantially better than most causes of clinical acute lung injury.

Transfusion-related acute lung injury (TRALI) following allogeneic stem cell transplant for acute myeloid leukemia

Transfusion-related acute lung injury (TRALI) is a serious complication of transfusion characterized by dyspnea, hypoxemia, hypotension, fever, and bilateral pulmonary infiltrates. Although the frequency is estimated at 1/1,120 to 1/5,000 transfusions, few cases have been reported after hematopoietic stem cell transplant. We report a case occurring in an allogeneic transplant recipient who developed acute respiratory distress and bilateral pulmonary infiltrates 2 hr after a platelet transfusion due to the presence of anti granulocyte antibody HNA-3a in the product. As there is a wide differential diagnosis for pulmonary infiltrates developing post transplant, TRALI may be under-recognized and should be considered in this setting.

Transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is an uncommon complication of allogeneic blood transfusion manifested typically by shortness of breath, fever, and hypotension. It has been estimated to occur in 0.04% to 0.16% per patient transfused. TRALI has been identified as an important cause of transfusion-related morbidity and mortality. Despite the increasing recognition that TRALI represents an important clinical syndrome, much about the pathogenesis, treatment, and prevention of TRALI is poorly understood or is controversial. In this report, what is known about TRALI is summarized and some of the areas in which knowledge and/or consensus are currently lacking are identified.

Recurrent transfusion-related acute lung injury

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a rare condition that is commonly associated with the transfusion of donor plasma containing WBC antibodies. Biologically active lipids that accumulate during storage of RBCs and platelets may also cause TRALI. There has been only one previously reported case of recurrent TRALI.

CASE REPORT

A patient received a transfusion 2 days after undergoing hysterectomy; she developed TRALI after receiving the transfusion. The patient recovered after being on ventilation for 6 days but received an additional transfusion and had a second episode of TRALI, which required further ventilation.

RESULTS

Laboratory investigation of the first episode of TRALI suggested the presence of HLA-A2 (N = 1) and granulocyte-specific IgM antibodies (N = 2) in the sera from three of the donors. All three sera reacted in crossmatch studies with the patient's granulocytes and lymphocytes. Lymphocyte-specific IgG antibodies were detected in the patient's serum. There was no evidence to suggest the involvement of WBC antibodies in the second episode of TRALI. Antibody screening of the donors' samples and both forward and reverse crossmatch studies were negative.

CONCLUSION

The first episode of TRALI seems to be due to the action of HLA-A2 and granulocyte-specific IgM antibodies. The second episode may have been due to the action of lipid neutrophil-priming agents in the donors' units in association with the patient's underlying pulmonary condition (i.e., recovering from lung injury). TRALI can recur if a patient requires further transfusion support shortly after an initial episode of TRALI.

A randomized controlled trial oftransfusion-related acute lung injury: is plasma from multiparous blood donors dangerous?

BACKGROUND

Transfusion-related acute lung injury (TRALI) and other posttransfusion reactions may be caused by granulocyte and/or HLA antibodies, which are often present in blood from multiparous donors. The purpose of this study was to compare the effects of plasma from multiparous donors with those of plasma from donors with no history of transfusion or pregnancy (control plasma) in a prospective, randomized, double-blind, crossover study.

STUDY DESIGN AND METHODS

Intensive care patients, judged to need at least 2 units of plasma, were randomly assigned to receive a unit of control plasma and, 4 hours later, a plasma unit from a multiparous donor (> or = 3 live births) or to receive the plasma units in opposite order. The patients were closely monitored, and body temperature, blood pressure, and heart rate were recorded. Blood samples for analysis of blood gases, TNFalpha, IL-1 receptor antagonist, soluble E selectin, and C3d complement factor were collected at least on four occasions (before and after the transfusion of each unit).

RESULTS

Transfusion of plasma from multiparous donors was associated with significantly lower oxygen saturation and higher TNFalpha concentrations than transfusion of control plasma. The mean arterial pressure increased significantly after the transfusion of control plasma, whereas plasma from multiparous donors had no effect on it. Five posttransfusion reactions were observed in 100 patients, in four cases after the transfusion of plasma from multiparous donors.

CONCLUSION

Plasma from multiparous blood donors may impair pulmonary function in intensive care unit patients.

Etiology of acute pulmonary edema during liver transplantation : a series of cases with analysis of the edema fluid

STUDY OBJECTIVES

To describe the clinical features of a group of patients who acutely developed pulmonary edema during orthotopic liver transplantation and to determine the nature (transudate vs exudate) of the edema.

DESIGN

Retrospective review of clinical records and radiographic studies.

SETTING

Operating room and ICU of a tertiary-care medical center hospital.

PATIENTS

End-stage liver disease patients undergoing orthotopic liver transplantation under general anesthesia.

INTERVENTIONS AND MEASUREMENTS

Pulmonary edema fluid obtained from seven patients within 15 min of first appearance was analyzed for protein content and compared with the protein content of a simultaneously obtained plasma sample. Hemodynamic data, fluid administration totals, and length of postoperative intubation and ICU stay were also collected.

RESULTS

Eight patients were identified. Six of the seven patients whose edema fluid was analyzed had edema fluid/plasma protein ratios > or =0.75, characteristic of increased permeability pulmonary edema (the one other patient had a ratio of 0.73). Hemodynamic monitoring at the time of onset of the edema effectively ruled out a cardiogenic etiology. One patient died intraoperatively; at autopsy, the cause of death was determined to be pulmonary fat embolization. In the other seven patients, production of edema fluid resolved within 6 h of admission to the ICU. The duration of ventilatory support ranged from 23 to 96 h, with a mean of 49 h.

CONCLUSIONS

The most likely cause of the reaction is transfusion-related acute lung injury (TRALI). An incidence of TRALI that is higher than previously reported in this population indicates that other elements, such as reperfusion of the newly implanted liver, may be contributing factors.

The HLA system in blood transfusion

The human leukocyte antigen (HLA) system, originally discovered as the result of a transfusion reaction, is now known to play a crucial role in many areas of clinical medicine. The main function of the HLA molecules is to present antigenic peptides to the immune system and in this way regulate the induction of immune responses. This is a highly regulated process which requires a close interaction between the HLA molecules, the antigenic peptide and the T cell receptor.HLA molecules are also known to be associated with a variety of autoimmune, non-autoimmune and infectious diseases and to restrict the antibody response to certain antigens and to vaccines. It is likely that the mechanism responsible for this restriction is the preferential presentation of antigen-derived peptides to T cells. Furthermore, HLA antigens, in contrast to most polymorphic molecules, have the ability to activate the immune system using two different pathways of T cell activation, the direct and indirect pathways. As a result of these features, HLA antigens and antibodies are responsible for some of the serious clinical complications of blood transfusion, and have an important influence on the outcome of solid organ and haemopoietic stem cell transplantation.