Reversing the effects of antiplatelet agents in the setting of intracranial hemorrhage: a look at the literature.

Patients are increasingly being prescribed antiplatelet agents (APAs) for a growing number of medical and surgical conditions. These agents are associated with an increased risk of hemorrhage, including intracranial hemorrhage (ICH). In the setting of warfarin use and ICH, strategies to reverse the drug effects have improved outcomes. No such strategy exists for APAs, and these patients continue to have poor posthemorrhage outcomes. One strategy is the use of platelet transfusions to provide functional, circulating platelets. Studies have shown mixed results regarding the benefit of this practice. Other strategies include the use of desmopressin and recombinant factor VIIa. More studies are necessary to delineate the effectiveness of the various strategies.

Risks and adverse outcomes associated with emergency-release red blood cell transfusion.

BACKGROUND: Group O red blood cell (RBC) units are used for emergency transfusions and are often uncrossmatched when transfused. We sought to determine the risk of alloimmunization and identify acute adverse outcomes of this practice. STUDY DESIGN AND METHODS: The transfusion medicine database was searched for emergency-release transfusion (ERT) episodes from January 2006 through December 2010. The data collected included age and sex of the recipient, blood bank history, survival after the ERT episode, antibody screen results, antibody identifications, and compatibility of released units. RESULTS: A total of 1444 ERT episodes took place involving 1407 patients. A total of 4144 RBC units were released. Of the 129 positive antibody screens, 34 had no antibody on further work-up, 14 had autoantibodies, 48 had a single antibody specificity, and 25 had multiple antibody specificities. Seven patients developed an antibody that could be attributed to the ERT episode, and 15 patients developed an antibody after ERT and additional RBC transfusions. There were 32 reported suspected transfusion reactions. No acute hemolytic transfusion reactions were reported. Seven patients were given a total of 10 incompatible RBC units. Of these patients, one developed a delayed serologic transfusion reaction. The rate of alloimmunization attributable to ERT was 3%. Overall, the rate of incompatible transfusion was less than 0.3% and the rate of a delayed hemolytic transfusion reaction was approximately 0.02%. CONCLUSION: There is minimal risk associated with the release of emergency uncrossmatched blood in the setting of an acutely bleeding patient. [Correction statement added after online publication 15-Oct-2012: the number of patients with autoantibodies, single antibody specificity and multiple antibody specificity has been update.].

Clinically significant anti-A(1) in a presumed ABO-identical hematopoietic stem cell transplant recipient: a case report.

BACKGROUND: Subgroups of the blood group A (ABO) are generally not considered ABO incompatible for hematopoietic progenitor cell (HPC) transplant. CASE REPORT: A 54-year-old female presented for HPC transplantation for acute leukemia. No HLA-matched donor was identified, so she received a peripheral blood stem cell graft from an HLA-mismatched unrelated donor. On pretransplant testing, both the donor and the recipient typed as blood group A. On Day +67 after transplant, the recipient had a transfusion reaction consisting of an increase in temperature, rigors, and shaking chills during infusion of a unit of group A red blood cells (RBCs). A transfusion reaction workup revealed an ABO discrepancy with both anti-A (1+) and anti-B (3+) identified in the patient's serum as well as a positive direct antiglobulin test with monoclonal anti-IgG antisera. Anti-A(1) were identified serologically and in an eluate. Hemolysis was clinically significant, requiring blood transfusion. No ABO typing discrepancies were found on pretransplant testing in either the recipient or the donor. DNA sequencing for blood group A subgroups performed after the transfusion reaction on blood collected before the transplant showed the donor to be type A(1) and the recipient as A(2) . Unfortunately, the patient experienced graft failure requiring reconditioning and reinfusion of additional cells from the original HPC donor. On Day +94 after the second transplant, the patient died with severe acute gastrointestinal graft-versus-host disease. CONCLUSION: This report describes a blood group A(2) patient who developed an anti-A(1) causing clinically significant hemolysis after HPC transplant from an A(1) donor.

Plasma exchange as a therapeutic option in patients with neurologic symptoms due to antibodies to voltage-gated potassium channels: a report of five cases and review of the literature.

Antibodies to voltage-gated potassium channels (VGKC) are associated with acquired neuromyotonia, limbic encephalitis, and Morvan's syndrome. The antibodies are often not associated with malignancy and have shown good clinical response to immunomodulatory therapies. A record review identified five patients with laboratory evidence of antibodies to VGKC who underwent plasma exchange (PE) as part of their immunosuppressive therapy for neurologic disease. Four of the patients presented with limbic encephalitis and one with neuromyotonia. Symptoms included memory impairment, seizures, and personality changes. All PE were 1.0 volume and were performed on an every-other-day schedule. Replacement fluid was 5% normal serum albumin except when a bleeding risk was identified and then fresh frozen plasma was added. Four of five patients were also receiving concurrent immunosuppressive therapy including corticosteroids. Of the five patients treated with PE, three had sustained improvement in symptoms for 6-17 months following PE. Two patients did not have signs of improvement at a limited follow-up. One patient had recurrence of her symptoms, which responded to additional PE. These cases, as well as the reports in the literature, suggest that PE could be a useful adjunctive therapy for patients with VGKC antibodies and neurologic symptoms.

Immunodetection of occult eosinophils in lung tissue biopsies may help predict survival in acute lung injury.

BACKGROUND: Acute lung injury (ALI) is a serious respiratory disorder for which therapy is primarily supportive once infection is excluded. Surgical lung biopsy may rule out other diagnoses, but has not been generally useful for therapy decisions or prognosis in this setting. Importantly, tissue and peripheral blood eosinophilia, the hallmarks of steroid-responsive acute eosinophilic pneumonia, are not commonly linked with ALI. We hypothesized that occult eosinophilic pneumonia may explain better outcomes for some patients with ALI. METHODS: Immunohistochemistry using a novel monoclonal antibody recognizing eosinophil peroxidase (EPX-mAb) was used to assess intrapulmonary eosinophil accumulation/degranulation. Lung biopsies from ALI patients (n = 20) were identified following review of a pathology database; 45% of which (i.e., 9/20) displayed classical diffuse alveolar damage (ALI-DAD). Controls were obtained from uninvolved tissue in patients undergoing lobectomy for lung cancer (n = 10). Serial biopsy sections were stained with hematoxylin and eosin (H&E) and subjected to EPX-mAb immunohistochemistry. RESULTS: EPX-mAb immunohistochemistry provided a >40-fold increased sensitivity to detect eosinophils in the lung relative to H&E stained sections. This increased sensitivity led to the identification of higher numbers of eosinophils in ALI patients compared with controls; differences using H&E staining alone were not significant. Clinical assessments showed that lung infiltrating eosinophil numbers were higher in ALI patients that survived hospitalization compared with non-survivors. A similar conclusion was reached quantifying eosinophil degranulation in each biopsy. CONCLUSION: The enhanced sensitivity of EPX-mAb immunohistochemistry uniquely identified eosinophil accumulation/degranulation in patients with ALI relative to controls. More importantly, this method was a prognostic indicator of patient survival. These observations suggest that EPX-mAb immunohistochemistry may represent a diagnostic biomarker identifying a subset of ALI patients with improved clinical outcomes.

The post-platelet 100,000 count: effects of platelet collection and future.

Currently, the majority of platelets transfused in the United States are collected by apheresis. The recent Food and Drug Administration guidance document published maintains that a postdonation platelet count for a donor remain >100,000/µL. During apheresis procedures, platelets are released from the splenic pool into circulation. This allows for higher postdonation platelet counts than anticipated. Some current plateletpheresis instruments take this into account when determining a safe product to be collected. On other instruments, the software does not allow for this correction. This may impact collections, but is expected to be resolved with a software update.

Use of plasma exchange in patients with heparin-induced thrombocytopenia: a report of two cases and a review of the literature.

Heparin-induced thrombocytopenia (HIT), which is characterized by thrombocytopenia and potentially serious thromboses, may develop in patients exposed to heparin anticoagulation. HIT is caused by antibodies to the heparin/platelet factor 4 (PF4) complex. Management of HIT involves discontinuation of heparin and anticoagulation with a nonheparin alternative such as a direct thrombin inhibitor (DTI). This poses a challenge in the management of patients who need to undergo cardiopulmonary bypass surgery (CPB), because CPB requires anticoagulation with heparin and standardized protocols for use of DTIs are not widely available. We report two patients with HIT who underwent successful CPB with heparin anticoagulation following plasma exchange (PE) to reduce heparin/PF4 antibody titers. Case 1 is a 46-year-old male with cardiac amyloidosis who needed urgent placement of a left ventricular assist device. Case 2 is a 34-year-old woman with acute myocarditis who needed placement of a biventricular assist device. Both patients had positive enzyme-linked immunosorbent assay assays for heparin/PF4 antibodies and clinical evidence of HIT before PE. Following PE and subsequent CPB, neither patient had clinical or laboratory evidence of HIT. The literature regarding the use of PE for the treatment of complications of HIT and as prophylaxis before CPB is reviewed.

The potential role of plasma exchange as a treatment for bilateral diffuse uveal melanocytic proliferation: a report of two cases.

Bilateral diffuse uveal melanocytic proliferation (BDUMP) is a rare paraneoplastic syndrome associated with gynecologic malignancies in women and pancreatic or lung carcinomas in men. The clinical presentation consists of the rapid onset of decreased visual acuity due to bilateral serous retinal detachment and cataracts. Pathologically, there is diffuse uveal thickening and proliferation of uveal melanocytes. The onset of blindness is often rapid, with some patients presenting with blindness. We describe the cases of two women with gynecologic malignancies who were treated with plasma exchange (PE) for BDUMP. After a course of five to seven procedures, their ocular disease stabilized. One patient has maintained her vision more than 1 year following the completion of the course of PE. The other patient, who also received treatment with corticosteroids, in addition to the PE, reported stable vision on telephone follow-up 9 months after presentation. These cases suggest that PE may be a treatment option in this rare paraneoplastic syndrome which has otherwise been reported to invariably result in vision loss.

Identification of anti-PP1P(k) in a blood donor and her family: a case report following her pregnancy and review.

Anti-PP1P(k) is a rare, biphasic antibody with the ability to cause immediate hemolytic transfusion reactions and early spontaneous abortions. The antibody is formed by individuals with the p phenotype. A blood donor with anti-PP1P(k) and the p phenotype was identified through routine donor screening. A sister was found to also be p phenotype. At that time, the sister was 24weeks pregnant. Subsequently, the original blood donor became pregnant. Both individuals were followed throughout their pregnancies and delivered infants without complications from anti-PP1P(k) antibodies. The literature regarding anti-PP1P(k), the p phenotype, and recurrent pregnancy loss in this setting is reviewed.

Temporal sequence of major biochemical events during blood bank storage of packed red blood cells.

BACKGROUND: We used sensitive spectroscopic techniques to measure changes in Band 3 oligomeric state during storage of packed red blood cells (RBC); these changes were compared to metabolic changes, RBC morphology, cholesterol and membrane protein loss, phospholipid reorganisation of the RBC membrane, and peroxidation of membrane lipid. The aim of the study was to temporally sequence major biochemical events occurring during cold storage, in order to determine which changes may underlie the structural defects in stored RBC. MATERIALS AND METHODS: Fifteen RBC units were collected from normal volunteers and stored under standard blood bank conditions; both metabolic changes and lipid parameters were measured by multiple novel assays including a new mass spectrometric measurement of isoprostane (lipid peroxidation) and flow cytometric assessment of CD47 expression. Band 3 oligomeric state was assessed by time-resolved phosphorescence anisotropy, and RBC morphology by microscopy of glutaraldehyde-fixed RBC. RESULTS: Extracellular pH decreased and extracellular potassium increased rapidly during cold storage. Band 3 on the RBC membrane aggregated into large oligomers early in the storage period and coincident with changes in RBC morphology. Membrane lipid changes, including loss of unesterified cholesterol, lipid peroxidation and expression of CD47, also changed early during the storage period. In contrast loss of acetylcholinesterase activity and haemolysis of RBC occurred late during storage. DISCUSSION: Our results demonstrate that changes in the macromolecular organisation of membrane proteins on the RBC occur early in storage and suggest that lipid peroxidation and/or oxidative damage to the membrane are responsible for irreversible morphological changes and loss of function during red cell storage.

Evolution of transthoracic fine needle aspiration and core needle biopsy practice: A comparison of two time periods, 1996-1998 and 2003-2005.

To examine the performance of our large pulmonary transthoracic fine needle aspiration/core biopsy (FNA/CB) practice over time, we performed a retrospective analysis of data from 333 consecutive procedures performed in 1996-1998 and 568 consecutive procedures performed in 2003-2005. Fluoroscopic guidance was performed more frequently in the earlier cohort, while a larger majority of procedures in the later cohort were by computed tomography (CT-guidance). A follow-up histologic diagnosis of cancer or clinical evidence of disease was considered the gold-standard. FNA/CB procedures during the later time period were performed on smaller lesions overall (3.60 cm versus 2.97 cm; P = 0.003) and malignant lesions also tended to be smaller (3.87 cm versus 3.14 cm; P = 0.006). Minimal improvements in sensitivity (94% versus 91%), specificity (99% versus 95%), diagnostic accuracy (95% versus 92%), negative predictive value (NPV) (80% versus 74%), and positive predictive value (PPV) (100% versus 99%) were noted during 2003-2005 when compared with 1996-1998 in all lesions. Larger improvements in sensitivity (94% versus 73%), diagnostic accuracy (95% versus 79%), and NPV (79% versus 50%) were identified in very small lesions (<1 cm) in the later patient cohort in comparison to the earlier patient cohort, as well as a significant decrease in total procedure complications. CT-guided transthoracic FNA/CB continues to be a very effective tool in our practice assessing lung lesions and performance has improved considerably at our institution for very small lesions.

Lipid emulsion solution: A novel cause of hemolysis in serum and plasma blood samples.

OBJECTIVES: After several hemolyzed blood samples were received in the laboratory, we investigated lipid emulsion/TPN as a novel cause of hemolysis. DESIGN AND METHODS: Whole blood was spiked with lipid emulsion and TPN. RESULTS: Hemolysis was proportional to the amount of lipid emulsion present in whole blood, with less hemolysis occurring in blood gas syringes compared to vacutainer tubes. CONCLUSION: Collection of specimens in blood gas syringes may prevent hemolysis in patients on lipid emulsion.