TRALI risk reduction: Donor and component management strategies

Transfusion-associated adverse events incidence and severity after the implementation of an active hemovigilance program with 24 h follow-up. A prospective cohort study

BACKGROUND

Hemovigilance (HV) is usually based on voluntary reports (passive HV). Our aim is to ascertain credible incidence, severity, and mortality of transfusion-associated adverse events (TAAEs) using an active HV program.

STUDY DESIGN AND METHODS

Prospective cohort study to estimate transfusion risk after 46,488 transfusions in 5830 patients, using an active HV program with follow-up within the first 24 h after transfusion. We compared these results to those with the previously established passive HV program during the same 30 months of the study. We explored factors associated with the occurrence of TAAEs using generalized estimating equations models.

RESULTS

With the active HV program TAAEs incidence was 57.3 (95% CI, 50.5-64.2) and mortality 1.1 (95% CI, 0.13-2.01) per 10,000 transfusions. Incidence with the new surveillance model was 14.0 times higher than with the passive. Most events occurred when transfusions had already finished (60.2%); especially pulmonary events (80.4%). Three out of five deaths and 50.3% of severe TAAEs were pulmonary. In the multivariate analysis surgical patients had half TAAEs risk when compared to medical patients (OR, 0.53; 95% CI, 0.34-0.78) and women had nearly twice the risk of a pulmonary event compared to men (OR, 1.84; 95% CI, 1.03-3.32). Patient's age, blood component type, or blood component shelf-life were unrelated to TAAEs risk.

DISCUSSION

Active hemovigilance programs provide additional data which may lead to better recognition and understanding of TAAEs and their frequency and severity.

Assessing the performance of a plateletpheresis unit at a tertiary-care academic medical center in Mexico: A 6-year experience

BACKGROUND

Optimization of platelet (PLT) apheresis collection is a priority to satisfy the increasing demand of hemato-oncology patients. We assessed the performance of a plateletpheresis unit supporting hematology patients.

STUDY DESIGN AND METHODS

This descriptive retrospective study included 561 plateletpheresis collections from 2013 to 2018. For data analysis, descriptive statistics and receiver operating characteristic (ROC) curve were used. A 5-item satisfaction questionnaire was analyzed.

RESULTS

Ninety percent of the donors were males. The median plateletpheresis time was 89 minutes; its success rate was 92.5%; median donor PLT count was 232 × 10⁹ /L, women median PLT count was 247 × 10⁹ /L vs 231x10⁹ /L in men (P = .017). Seventy-seven percent donors were candidates for a double product and 24.5% were processed; 20.8% of these donors had a weight ≤75 and 79.2% >75 kg, P = .003, and 6.6% were women and 93.4% men, P = .161. Thirty-six of donors had ≥250 × 10⁹ /L and 16.8% was processed as a triple product. ROC analysis showed that with donor PLT counts ≥200 × 10⁹ /L the sensitivity for obtaining double products was 0.981 and specificity 0.714, with an area under the curve (AUC) = 0.877. The adverse effect rate was 4.3%. Of the potential donors, 6.3% were rejected. The cost of processing single or double products was 430 USD. Comfort and time spent during plateletpheresis were areas for improvement.

CONCLUSION

Platelet count and donor weight predicted PLT yield and obtaining double products. Women had higher PLT counts, but no significant difference was found between donor gender and processed products. Assessment of the apheresis unit can help to improve its performance.

Maternal HLA Ib Polymorphisms in Pregnancy Allo-Immunization

During pregnancy the formation of alloreactive anti-human leukocyte antigen (HLA) antibodies are a major cause of acute rejection in organ transplantation and of adverse effects in blood transfusion. The purpose of the study was to identify maternal HLA class Ib genetic factors associated with anti-HLA allo-immunization in pregnancy and the degree of tolerance estimated by IgG4 expression. In total, 86 primiparous women with singleton pregnancies were included in the study. Maternal blood samples and umbilical cord samples were collected at delivery. Clinical data were obtained. Maternal blood serum was screened for HLA class I and II antibodies, identification of Donor Specific Antibody (DSA), activation of complement measured by C1q and IgG4 concentrations. Mothers were genotyped for HLA class Ib (HLA-E, -F and -G). Anti-HLA class I and II antibodies were identified in 24% of the women. The maternal HLA-E*01:06 allele was significantly associated with a higher fraction of anti-HLA I immunization (20.0% vs. 4.8%, p = 0.048). The maternal HLA-G 3’-untranslated region UTR4-HLA-G*01:01:01:05 haplotype and the HLA-F*01:03:01 allele were significantly associated with a low anti-HLA I C1q activation (16.7% vs. 57.1%, p = 0.028; 16.7% vs. 50.0%, p = 0.046; respectively). Both HLA‑G and HLA-F*01:03:01 showed significantly higher levels of IgG4 compared with the other haplotypes. The results support an association of certain HLA class Ib alleles with allo-immunization during pregnancy. Further studies are needed to elucidate the roles of HLA-E*01:06, HLA-F*01:03 and HLA‑G UTR4 in reducing the risk for allo-immunization.

Maternal HLA-G*01:01:01:04 protects from anti-HLA-class II immunization in pregnant women

Factors determining anti-HLA immunization are poorly understood, although anti-HLA immunization following pregnancy is well described. The HLA-G molecule has been extensively described for its implication in immunological tolerance, especially during pregnancy. Transplant studies show an association between HLA-G haplotypes and alloimmunization. Our aim was to investigate the association of HLA-G haplotypes with anti-HLA class I and II immunization in a cohort of women having experienced one or more pregnancies and with no transfusion history. Maternal blood samples (n=270) collected at delivery and formerly screened for anti-HLA antibodies, HLA-A and HLA-B antigens, were screened by NGS for HLA-G gene polymorphism. Univariate analysis further confirmed that the number of pregnancies was significantly associated with anti-HLA class I immunization, whereas no other variable remained significant after Bonferroni correction. Our results showed however that anti-HLA class II immunization was associated with the number of children whereas the HLA-G*01:01:01:04 allele was protective against this immunization.

Antibodies to major histocompatibility complex class II antigens directly prime neutrophils and cause acute lung injury in a two-event in vivo rat model

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a significant cause of mortality, especially after transfusions containing antibodies to major histocompatibility complex (MHC) class II antigens. We hypothesize that a first event induces both 1) polymorphonuclear neutrophils (PMNs) to express MHC class II antigens, and 2) activation of the pulmonary endothelium, leading to PMN sequestration, so that the infusion of specific MHC class II antibodies to these antigens causes PMN-mediated acute lung injury (ALI).

STUDY DESIGN AND METHODS

Rats were treated with saline (NS), endotoxin (lipopolysaccharide [LPS]), or cytokines (interferon-γ [IFNγ], macrophage colony-stimulating factor [MCSF], tumor necrosis factor-α [TNFα]); the PMNs were isolated; and the surface expression of the MHC class II antigen OX6 and priming by OX6 antibodies were measured by flow cytometry or priming assays.

RESULTS

A two-event model of ALI was completed with NS, LPS, or IFNγ/MCSF/TNFα (first events) and the infusion of OX6 (second event). Compared with NS incubation, rats treated with either LPS or IFNγ/MCSF/TNFα exhibited OX6 PMN surface expression, OX6 antibodies primed the formyl-methionyl-leucyl phenylalanine (fMLF)-activated respiratory burst, and PMN sequestration was increased. OX6 antibody infusion into LPS-incubated or IFNγ/MCSF/TNFα-incubated rats elicited ALI, the OX6 antibody was present on the PMNs, and PMN depletion abrogated ALI.

CONCLUSION

Proinflammatory first events induce PMN MHC class II surface expression, activation of the pulmonary endothelium, and PMN sequestration such that the infusion of cognate antibodies precipitates TRALI.

Antibody-mediated transfusion-related acute lung injury; from discovery to prevention

Transfusion-related acute lung injury (TRALI), a syndrome of respiratory distress caused by blood transfusion, is the leading cause of transfusion-related mortality. The majority of TRALI cases have been related to passive infusion of human leucocyte antigen (HLA) and human neutrophil antigen (HNA) antibodies in donor blood. In vitro, ex vivo and in vivo animal models have provided insight in TRALI pathogenesis. The various classes of antibodies implicated in TRALI appear to have different pathophysiological mechanisms for the induction of TRALI involving endothelial cells, neutrophils, monocytes and, as very recently has been discovered, lymphocytes. The HLA and HNA-antibodies are found mainly in blood from multiparous women as they have become sensitized during pregnancy. The incidence of TRALI has decreased rapidly following the introduction of a male-only strategy for plasma donation. This review focuses on pre-clinical and clinical studies investigating the pathophysiology of antibody-mediated TRALI.

Transfusion-related acute lung injury and potential risk factors among the inpatient US elderly as recorded in Medicare claims data, during 2007 through 2011

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a serious complication leading to pulmonary edema and respiratory failure. This study's objective was to assess TRALI occurrence and potential risk factors among inpatient US elderly Medicare beneficiaries, ages 65 and older, during 2007 through 2011.

STUDY DESIGN AND METHODS

This retrospective claims-based study utilized large Medicare administrative databases. Transfusions were identified by recorded procedure and revenue center codes. TRALI was ascertained via ICD-9-CM diagnosis code. The study evaluated TRALI rates among the inpatient elderly overall and by calendar year, age, sex, race, blood components, and units transfused. Logistic regression analyses were used to assess potential risk factors.

RESULTS

Of 11,378,264 inpatient transfusion stays for elderly Medicare beneficiaries, 2556 had a recorded TRALI diagnosis code, an overall rate of 22.46 per 100,000 stays. TRALI rates were higher for platelet (PLT)- and plasma-containing transfusions and increased by year and number of units transfused (p < 0.0001). Significantly higher odds of TRALI were also found for persons ages 65 to 79 years versus more than 79 years (OR, 1.19; 95% confidence interval CI, 1.09-1.29), females versus males (OR, 1.26; 95% CI, 1.16-1.38), white versus nonwhite (OR, 1.43; 95% CI, 1.27-1.66), and with 6-month histories of postinflammatory pulmonary fibrosis (OR, 1.89; 95% CI, 1.52-2.20), tobacco use (OR, 1.16; 95% CI, 1.00-1.26), and other diseases.

CONCLUSION

Our study among the elderly suggests TRALI to be a severe event and identifies a substantially increased TRALI occurrence with greater number of units and with PLT- or plasma-containing transfusions. The study also suggests importance of underlying health conditions, prior recipient alloimmunization, and nonimmune mechanism in TRALI development among the elderly.

The merits of cell salvage in arthroplasty surgery: an overview

Arthroplasty entails considerable exposure to allogenic blood transfusion. Cell salvage with washing is a contemporary strategy that is not universally used despite considerable potential benefits. We searched Embase and Medline to determine if blood salvage with washing during primary and/or revision hip and knee arthroplasty results in lower rates of transfusion and postoperative complications. We included 10 studies in our analysis, which we rated according to Downs and Black criteria. With primary knee arthroplasty, there was a reduction in transfusion rate from 22% to 76% and a 48% reduction in transfusion volume (n = 887). With primary hip arthroplasty, there was a reduction from 69% to 73% in transfusion rate and a 31% reduction in transfusion volume (n = 239). There was a significant decrease in length of hospital stay (9.6 v. 13.6 d). Studies of revision arthroplasty reported a 31%-59% reduction in transfusion volume (n = 241). The available evidence demonstrates reduced exposure to allogenic blood with the use of salvage systems. Studies have been underpowered to detect differences in infection rates and other postoperative complications. Future cost analysis is warranted.

Massive transfusion in the trauma patient: Continuing Professional Development

PURPOSE

Massive transfusion has recently been given a dynamic definition, namely, the replacement of more than four red cell concentrates within an hour. The purpose of this continuing professional development module is to review the pathophysiology of hemorrhagic shock in the trauma patient and the current management strategies of the massively bleeding trauma patient.

PRINCIPAL FINDINGS

The massively bleeding trauma patient requires concurrent hemorrhage control and blood replacement therapy. Although there are many complications of massive transfusions, such as acid-base disturbances, electrolyte abnormalities, and hypothermia, perhaps the most difficult aspect to manage is acute trauma coagulopathy. Historically, coagulopathy was attributed to dilution of coagulation factors; however, recent accumulated evidence indicates that it is a multifactorial process associated with hypoperfusion, factor consumption, and hyperfibrinolysis. In an attempt to minimize acute trauma coagulopathy, massive transfusion protocols with equal ratios of red cell concentrates, frozen plasma, and platelets have been proposed. This type of hemostatic resuscitation, with near equal ratios of blood and blood products, has improved survival, but it is not without risk. In addition to the rapid and effective restoration of blood volume, the specific goal of transfusion management should be to maintain the patient's oxygen carrying capacity, hemostasis, and biochemistry.

CONCLUSION

The current literature does not permit firm conclusions to be drawn regarding optimal transfusion ratios. It remains appropriate, however, to devise a massive transfusion protocol at the institutional level that provides treating physicians with rapid delivery of a reasonable initial ratio of products. This would permit patient-centred management with an emphasis on surgical control of bleeding, maintenance of normothermia, avoidance of electrolyte abnormalities, acid-base balance, and the timely delivery of blood products.

OBJECTIVES

After reading this module, the reader should be able to: 1. Enumerate the complications associated with massive transfusion in the trauma context; 2. Understand how the coagulopathy present in the trauma patient differs from that seen in the elective setting; 3. Identify the modifications suggested by the recent literature for the management of massive transfusion in the trauma setting; 4. Appreciate the evidence for the institution of massive transfusion protocols.

Transfusion-related acute lung injury: a preventable syndrome?

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related morbidity and mortality. Recent insights into the pathophysiology of TRALI have led to various preventive strategies. Strategies in donor management range from antibody testing of sensitized donors to the deferral of female plasma donors altogether. However, knowledge on the efficacy of measures to reduce TRALI is limited. In addition, the various measures may lead to a substantial loss of donors, hampering steady blood supply. Thereby, consensus among countries and blood-collecting facilities regarding the optimal strategy to prevent TRALI is lacking. In this review, the advantages and disadvantages of various preventive measures to prevent TRALI are discussed, related to both patient factors as well as blood component-processing strategies, including transfusion policy, donor management and practices of preparation and storage conditions of blood components.

Comparison of hemostatic matrix and standard hemostasis in patients undergoing primary TKA

Bleeding after total knee arthroplasty increases the risk of pain, delayed rehabilitation, blood transfusion, and transfusion-associated complications. The authors compared pre- and postoperative decreases in hemoglobin as a surrogate for blood loss in consecutive patients treated at a single institution by the same surgeon (J.L.C.) using conventional hemostatic methods (electrocautery, suturing, or manual compression) or a gelatin and thrombin-based hemostatic matrix during total knee arthroplasty. Data were collected retrospectively by chart review. The population comprised 165 controls and 184 patients treated with hemostatic matrix. Median age was 66 years (range, 28-89 years); 66% were women. The arithmetic mean ± SD for the maximal postoperative decrease in hemoglobin was 3.18 ± 0.94 g/dL for controls and 2.19 ± 0.83 g/dL for the hemostatic matrix group. Least squares means estimates of the group difference (controls-hemostatic matrix) in the maximal decrease in hemoglobin was 0.96 g/dL (95% confidence interval, 0.77-1.14 mg/dL; P<.0001). Statistically significant covariate effects were observed for preoperative hemoglobin level (P<.0001) and body mass index (P=.0029). Transfusions were infrequent in both groups. The frequency of acceptable range of motion was high (control, 88%; hemostatic matrix, 84%). In both groups, overall mean tourniquet time was approximately 1 hour, and the most common length of stay was 3 to 5 days. No serious complications related to the hemostatic agent were observed. These data demonstrate that the use of a flowable hemostatic matrix results in less reduction in hemoglobin than the use of conventional hemostatic methods in patient undergoing total knee arthroplasty.

The pro-inflammatory effects of platelet contamination in plasma and mitigation strategies for avoidance

BACKGROUND AND OBJECTIVES

Plasma and platelet concentrates are disproportionately implicated in transfusion-related acute lung injury (TRALI). Platelet-derived pro-inflammatory mediators, including soluble CD40 ligand (sCD40L), accumulate during storage. We hypothesized that platelet contamination induces sCD40L generation that causes neutrophil [polymorphonuclear leucocyte (PMN)] priming and PMN-mediated cytotoxicity.

MATERIALS AND METHODS

Plasma was untreated, centrifuged (12,500 g) or separated from leucoreduced whole blood (WBLR) prior to freezing. Platelet counts and sCD40L concentrations were measured 1-5 days post-thaw. The plasma was assayed for PMN priming activity and was used in a two-event in vitro model of PMN-mediated human pulmonary microvascular endothelial cell (HMVEC) cytotoxicity.

RESULTS

Untreated plasma contained 42±4·2×10(3)/μl platelets, which generated sCD40L accumulation (1·6-eight-fold vs. controls). Priming activity and HMVEC cytotoxicity were directly proportional to sCD40L concentration. WBLR and centrifugation reduced platelet and sCD40L contamination, abrogating the pro-inflammatory potential.

CONCLUSION

Platelet contamination causes sCD40L accumulation in stored plasma that may contribute to TRALI. Platelet reduction is potentially the first TRALI mitigation effort in plasma manufacturing.

Manufacture of pooled platelets in additive solution and storage in an ELX container after an overnight warm temperature hold of platelet-rich plasma

The processing of whole blood-derived platelet-rich plasma (PRP) to a platelet concentrate and platelet-poor plasma is currently performed within 8 hours to comply with the requirements to manufacture fresh frozen plasma. Maintaining PRP at room temperature for a longer period can have the advantage of shifting the completion of component manufacture onto day shifts. Pairs of ABO-identical prepooled platelets were manufactured by the PRP method, using the current approach with platelet storage in a CLX HP container (Pall Medical, Covina, CA) and plasma, or a novel approach with an 18- to a 24-hour room temperature hold of the PRP and the manufacture of pooled platelets in a glucose-containing additive solution (AS) and storage in a new ELX container (Pall Medical). Standard in vitro assays were performed on days 2, 5, and 7. The results showed that the AS platelets in ELX have in vitro characteristics that are equivalent or superior to those of the standard product.

An association between decreased cardiopulmonary complications (transfusion-related acute lung injury and transfusion-associated circulatory overload) and implementation of universal leukoreduction of blood transfusions

BACKGROUND

Cardiopulmonary adverse events after transfusion include transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO), which are potentially lethal and incompletely understood.

STUDY DESIGN AND METHODS

To determine whether the incidence of TRALI and TACO was affected by leukoreduction we conducted a retrospective, before-and-after study of acute transfusion reactions for the 7years before and after introduction of universal leukoreduction in 2000, involving 778,559 blood components.

RESULTS

Substantial decreases occurred in the rates of TRALI (-83%; from 2.8 cases per 100,000 components before to 0.48 after universal leukoreduction; p=0.01), TACO (-49%; 7.4 to 3.8 cases per 100,000; p=0.03), and febrile reactions (-35%; 11.4 to 7.4 cases per 10,000; p<0.0001). The incidence of allergic reactions remained unchanged (7.0 per 100,000 before and after universal leukoreduction). These outcomes were primarily attributable to decreased TRALI and/or TACO associated with red blood cell (RBC) and platelet (PLT) transfusions (-64%) with notably smaller decreases associated with fresh-frozen plasma or cryoprecipitate transfusions (-29%). The incidence of TRALI and/or TACO after 28,120 washed RBC and 69,325 washed transfusions was zero.

CONCLUSION

These data suggest novel hypotheses for further testing in animal models, in prospective clinical trials, and via the new US hemovigilance system: 1) Is TACO or TRALI mitigated by leukoreduction? 2) Is the mechanism of TACO more complex than excessive blood volume? and 3) Does washing mitigate TRALI and TACO due to PLT and RBC transfusions?

Results of HLA antibody testing using ELISA vs the fluorescent bead method and retrospective review of data for recipients of packed RBCs and platelets from male HLA-immunized donors

We reviewed HLA antibody testing results using an enzyme-linked immunosorbent assay (ELISA) for all male blood donors at our institution during a 3.5-month period to look for HLA immunization. Confirmatory testing of 33 blood samples positive for HLA class I and/or II antibodies was performed using the fluorescent bead method. A retrospective review of recipients of packed RBCs and platelets processed from these 33 HLA-immunized male donors were conducted to identify transfusion-related acute lung injury and cognate antigens. The agreement rates between the methods for HLA class I and II antibodies were 21% (7/33) and 6% (2/33), respectively. We noted HLA antibodies in the male donors corresponding to cognate antigens in 2 recipients of packed RBCs and in 3 recipients of platelets. Of 8 donors positive for HLA antibodies, 5 did not have a history of blood transfusion. We conclude that ELISA was too sensitive and had a high false-positive rate for the detection of HLA class II antibodies.

Transfusion-related acute lung injury after transfusion of maternal blood: a case-control study

STUDY DESIGN

This is a single-center retrospective case-control study of 7 transfusion-related acute lung injury (TRALI) cases and 28 controls in the pediatric spinal surgery population.

OBJECTIVE

To determine the association between maternal transfusion and risk of TRALI in pediatric spinal surgery patients.

SUMMARY OF BACKGROUND DATA

Previous studies support a "2-hit" model for the pathogenesis of TRALI-activation and sequestration of neutrophils in the pulmonary vasculature followed by transfusion of a biologic response modifier such as antileukocyte antibodies. Maternal donation of blood products is a potential risk factor for TRALI because of the development of antileukocyte antibodies during pregnancy. Until now there have been no studies specifically addressing the risk of TRALI following maternal transfusions.

METHODS

This is a retrospective case-control study of 7 TRALI cases with 4 controls per case, matched by strata for volume of plasma transfused. All cases identified by the Transfusion Biology and Medicine Specialized Center of Clinically Oriented Research with a TRALI diagnosis were eligible for inclusion. Electronic medical records and operative notes were reviewed to obtain demographic data, diagnosis, surgical approach, and number of spine levels for each operation.

RESULTS

An increased prevalence of maternal blood transfusion was found among the TRALI cases compared with the control cases: 43% (3 of 7) versus 7% (2 of 28), P = 0.044. There were otherwise no statistical differences between the groups, including age, gender, surgical approach, number of spinal levels, or type of blood product transfused.

CONCLUSION

Pediatric patients undergoing spinal surgery may be at increased risk for the development of TRALI following the transfusion of maternal blood products. Accordingly, we recommend that directed donation of maternal blood products should be avoided in this population. This study also found that TRALI may be underrecognized and underreported to the transfusion service.

The status of pathogen-reduced plasma

Efforts to reduce the risk of transfusion-transmitted infectious diseases began more than 4 decades ago with testing donated blood for syphilis. During the subsequent 4 decades, the number of recognized blood-borne transmissible agents and new laboratory tests has proliferated to a logistical breaking point. Further, the number of "emerging agents" which might enter the donor population is increasing continuously. In the search for an alternative to the laboratory testing strategy, pathogen-reduction technologies have emerged as the most promising. The model for this paradigm is pasteurization of a bottle of cow's milk. No matter what infective agent may be present in freshly collected cow's milk, pasteurization, i.e., a generic purification process can eliminate all potential infectivity, while preserving its essential biological properties--and an affordable cost. Several manufacturers have undertaken the challenge of developing a pathogen-reduction technology for blood components. Some novel technologies have proven successful for pooled plasma derivatives such as immune globulins, coagulation factor concentrate concentrates and albumin. The greatest challenge is finding a technology that is suitable for red blood cell and platelet components, whereas significant progress has been made already for pathogen-reduced plasma products. The present review addresses the status of implementation of pathogen-reduced plasma products in the global market. Some blood centers and hospital blood banks in Europe and the Middle East have begun to distribute pathogen-reduced plasma, but no pathogen-reduced plasma product is presently approved by the US Food and Drug Administration. While many observers in the United States focus on the regulatory process as the impediment to widespread implementation, the real challenge will be paying the surcharge for the pathogen-reduction process - an as yet unspecified figure - but likely to add a very substantial amount to the annual healthcare budget.

Transfusion therapy and acute lung injury

Transfusion-related acute lung injury (TRALI) remains the deadliest complication of transfusion. Consensus definitions of TRALI have been developed but remain controversial. Recent evidence supports a strong relationship between blood transfusion and the development of acute lung injury in the critically ill and trauma population. Plasma and platelet transfusions have been the most commonly implicated blood products. The 'two hit' model may best explain the immune and nonimmune pathogenesis of TRALI. Current treatment remains largely supportive; effective measures for decreasing the incidence of TRALI include the use of predominantly male plasma and apheresis platelets. Greater understanding of the blood component and patient risk factors for TRALI will hopefully lead to novel treatment and preventive strategies for reducing the risk of this life-threatening syndrome.

Pulmonary disorders, including vocal cord dysfunction

The lung is a very complex immunologic organ and responds in a variety of ways to inhaled antigens, organic or inorganic materials, infectious or saprophytic agents, fumes, and irritants. There might be airways obstruction, restriction, neither, or both accompanied by inflammatory destruction of the pulmonary interstitium, alveoli, or bronchioles. This review focuses on diseases organized by their predominant immunologic responses, either innate or acquired. Pulmonary innate immune conditions include transfusion-related acute lung injury, World Trade Center cough, and acute respiratory distress syndrome. Adaptive immunity responses involve the systemic and mucosal immune systems, activated lymphocytes, cytokines, and antibodies that produce CD4(+) T(H)1 phenotypes, such as for tuberculosis or acute forms of hypersensitivity pneumonitis, and CD4(+) T(H)2 phenotypes, such as for asthma, Churg-Strauss syndrome, and allergic bronchopulmonary aspergillosis.

Transfusion therapy in hemorrhagic shock

PURPOSE OF REVIEW

Bleeding and death from hemorrhage remain a leading cause of morbidity and mortality in the trauma population. Early resuscitation of these gravely injured patients has changed significantly over the past several years. The concept of damage control resuscitation has expanded significantly with the experience of the US military in southwest Asia. This review will focus on this resuscitation strategy of transfusing blood products (red cells, plasma, and platelets) early and often in the exsanguinating patient.

RECENT FINDINGS

In trauma there are no randomized controlled trials comparing the current damage control hematology concept to more traditional resuscitation methods. But the overwhelming conclusion of the data available support the administration of a high ratio of plasma and platelets to packed red blood cells. Several large retrospective studies have shown ratios close to 1: 1 will result in higher survival.

SUMMARY

The current evidence supports that the acute coagulopathy of trauma is present in a high percentage of trauma patients. Patients who will require a massive transfusion will have improved outcomes the earlier that this is identified and the earlier that damage control hematology is instituted. Current evidence does not describe the best ratio but the preponderance of the data suggests it should be greater than 2: 3 plasma-to-packed red blood cells.