Transfusion-related acute lung injury

Preemptive mechanical ventilation can block progressive acute lung injury

Mortality from acute respiratory distress syndrome (ARDS) remains unacceptable, approaching 45% in certain high-risk patient populations. Treating fulminant ARDS is currently relegated to supportive care measures only. Thus, the best treatment for ARDS may lie with preventing this syndrome from ever occurring. Clinical studies were examined to determine why ARDS has remained resistant to treatment over the past several decades. In addition, both basic science and clinical studies were examined to determine the impact that early, protective mechanical ventilation may have on preventing the development of ARDS in at-risk patients. Fulminant ARDS is highly resistant to both pharmacologic treatment and methods of mechanical ventilation. However, ARDS is a progressive disease with an early treatment window that can be exploited. In particular, protective mechanical ventilation initiated before the onset of lung injury can prevent the progression to ARDS. Airway pressure release ventilation (APRV) is a novel mechanical ventilation strategy for delivering a protective breath that has been shown to block progressive acute lung injury (ALI) and prevent ALI from progressing to ARDS. ARDS mortality currently remains as high as 45% in some studies. As ARDS is a progressive disease, the key to treatment lies with preventing the disease from ever occurring while it remains subclinical. Early protective mechanical ventilation with APRV appears to offer substantial benefit in this regard and may be the prophylactic treatment of choice for preventing ARDS.

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.

Acute respiratory failure in the patient with cancer: diagnostic and management strategies

Acute respiratory failure (ARF) remains the major reason for admission to the intensive care unit (ICU) in patients with cancer and is often associated with high mortality, especially in those who require mechanical ventilation. The diagnosis and management of ARF in patients who have cancer pose unique challenges to the intensivist. This article reviews the most common causes of ARF in patients with cancer and discusses recent advances in the diagnostic and management approaches of these disorders. Timely diagnosis and treatment of reversible causes of respiratory failure, including earlier use of noninvasive ventilation and judicious ventilator and fluid management in patients with acute lung injury, are essential to achieve an optimal outcome. Close collaboration between oncologists and intensivists helps ensure that clear goals, including direction of treatment and quality of life, are established for every patient with cancer who requires mechanical ventilation for ARF.

The role of erythropoietin in the acute phase of trauma management: evidence today

Trauma patients often present in a state of haemorrhagic shock. Blood products remain the gold standard of resuscitation, but allogeneic blood transfusions (ABTs) are associated with several risks. The stimulating effect of recombinant-erythropoietin (EPO-A) on erythropoiesis has raised interest in its administration as an alternative. The existing evidence on the early use of EPO-A in the acute phase of trauma patients management consists of only 14 publications. The level of evidence of these studies and the number of treated patients was not found to be adequate to support its generalised use, despite their favourable results. Its safety profile, the preliminary proofs of its efficacy, and the additional cyto-protective properties of EPO-A strongly encourage further controlled studies assessing its use in the acute setting of initial trauma management.

Role of biological modifiers regulating the immune response after trauma

Trauma induces a profound immunological dysfunction. This is characterised by an early state of hyperinflammation, followed by a phase of immunosuppression with increased susceptibility to infection and multiple organ failure. Therapeutic strategies directed at restoring immune homeostasis after traumatic injuries have largely failed in translation from "bench to bedside". The present review illustrates the role of biological modifiers of the posttraumatic immune response by portraying different modalities of therapeutic immune modulation. The emphasis is placed on anti-inflammatory (steroids) and immune-stimulatory (interferon) pharmacological strategies and modified resuscitative strategies, as well as more unconventional immunomodulatory approaches, such as immunonutrition.

Hereditary angioedema: a decade of human C1-inhibitor concentrate therapy

BACKGROUND

C1-inhibitor (C1-INH) is a serine protease inhibitor regulating the complement, kinin-kallikrein, coagulation, and fibrinolytic systems. Hereditary angioedema (HAE) is caused by an inherited deficiency of C1-INH characterized by sudden, recurrent edematous swellings of the subcutaneous or submucosal tissues. The optional therapy for the acute management of HAE is administration of human C1-INH (hC1-INH) concentrate. However, hC1-INH is not available in many countries, in which case fresh frozen plasma is an alternative.

OBJECTIVE

To summarize our experience with hC1-INH concentrate in patients with HAE.

METHODS

Clinical and laboratory information on the effectiveness and safety of hC1-INH administered to relieve 468 acute edematous attacks in 61 patients with HAE was analyzed.

RESULTS

Severe abdominal or subcutaneous attacks and laryngeal edema were consistently relieved by the administration of 500 U hC1-INH concentrate. Symptoms improved within 15 to 60 minutes of administration. Progression of the attacks was never observed, and there were no recurrent attacks within 72 hours. hC1-INH concentrate requirements did not change after repeated use. hC1-INH concentrate proved effective in the management of 94 attacks in 22 children and 6 attacks in 4 pregnant women. Adverse reactions, viral infections, and antibody formation against the purified protein did not occur.

CONCLUSION

The administration of hC1-INH concentrate in HAE is highly effective and safe for the treatment of acute attacks and short-term prophylaxis and in pediatric patients and pregnant women.

CLINICAL IMPLICATIONS

Human C1-INH concentrate is effective and safe for the treatment of acute HAE attacks as well as for short-term prophylaxis.

Vascular endothelium summary statement V: Pulmonary hypertension and acute lung injury: public health implications

Although relatively rare, pulmonary hypertension can be devastating for those individuals who are affected and has significant societal implications. The 2003 WHO classification separates PAH (idiopathic, specific disease linked) from pulmonary hypertension related to lung disease, thromboembolic disease, and pulmonary venous hypertension. Another form of pulmonary hypertension, persistent pulmonary hypertension (PPHN), occurs in the newborn. In general, PPHN is thought to be responsible for approximately 10% of admissions to neonatal intensive care units and can be a complicating factor in 5 of 1000 live births. Acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) are complex disorders that pose a significant threat to critically ill patients. They are usually related to direct lung injury or indirect injury from sepsis, trauma, and other disorders. Although these pulmonary disorders reflect distinct pathophysiologic mechanisms, current evidence strongly suggests that a common denominator underlying many of the established molecular and cellular elements is endothelial cell activation and dysfunction. This summary statement briefly summarizes the state of the science and suggests future avenues of public health research.