Final statement from the consensus conference on platelet transfusion

ACG Clinical Guideline: Management of Patients With Acute Lower Gastrointestinal Bleeding

This guideline provides recommendations for the management of patients with acute overt lower gastrointestinal bleeding. Hemodynamic status should be initially assessed with intravascular volume resuscitation started as needed. Risk stratification based on clinical parameters should be performed to help distinguish patients at high- and low-risk of adverse outcomes. Hematochezia associated with hemodynamic instability may be indicative of an upper gastrointestinal (GI) bleeding source and thus warrants an upper endoscopy. In the majority of patients, colonoscopy should be the initial diagnostic procedure and should be performed within 24 h of patient presentation after adequate colon preparation. Endoscopic hemostasis therapy should be provided to patients with high-risk endoscopic stigmata of bleeding including active bleeding, non-bleeding visible vessel, or adherent clot. The endoscopic hemostasis modality used (mechanical, thermal, injection, or combination) is most often guided by the etiology of bleeding, access to the bleeding site, and endoscopist experience with the various hemostasis modalities. Repeat colonoscopy, with endoscopic hemostasis performed if indicated, should be considered for patients with evidence of recurrent bleeding. Radiographic interventions (tagged red blood cell scintigraphy, computed tomographic angiography, and angiography) should be considered in high-risk patients with ongoing bleeding who do not respond adequately to resuscitation and who are unlikely to tolerate bowel preparation and colonoscopy. Strategies to prevent recurrent bleeding should be considered. Nonsteroidal anti-inflammatory drug use should be avoided in patients with a history of acute lower GI bleeding, particularly if secondary to diverticulosis or angioectasia. Patients with established high-risk cardiovascular disease should not stop aspirin therapy (secondary prophylaxis) in the setting of lower GI bleeding. [corrected]. The exact timing depends on the severity of bleeding, perceived adequacy of hemostasis, and the risk of a thromboembolic event. Surgery for the prevention of recurrent lower gastrointestinal bleeding should be individualized, and the source of bleeding should be carefully localized before resection.

Concepts of blood transfusion in adults

Recent progress has been made in the identification and implementation of best transfusion practices on the basis of evidence-based clinical trials, published clinical practice guidelines, and process improvements for blood use and clinical patient outcomes. However, substantial variability persists in transfusion outcomes for patients in some clinical settings--eg, patients undergoing cardiothoracic surgery. This variability could be the result of insufficient understanding of published guidelines; different recommendations of medical societies, including the specification of a haemoglobin concentration threshold to use as a transfusion trigger; the value of haemoglobin as a surrogate indicator for transfusion benefit, even though only changes in concentration and not absolute red cell mass of haemoglobin can be identified; and disagreement about the validity of the level 1 evidence for clinical practice guidelines. Nevertheless, institutional experience and national databases suggest that a restrictive blood transfusion approach is being increasingly implemented as best practice.

Filter membrane-based automated therapeutic plasma exchange: a report of two cases from Nigeria

These case reports demonstrated the diagnostic dilemma encountered in patients with systemic lupus erythematosus and thrombotic thrombocytopenic purpura particularly in settings with limited diagnostic facilities and laboratory support. The similarities in the diagnostic criteria for both conditions make clear distinction as well as management decisions difficult. We present the difficulties encountered with both the diagnosis and the management of these two patients that were managed in our facility.

Platelet transfusion threshold in patients with upper gastrointestinal bleeding: a systematic review

BACKGROUND

There exists uncertainty as to the optimal platelet values when managing patients with nonvariceal upper gastrointestinal (GI) bleeding. GOALS AND STUDY: A systematic review was carried out to determine the optimal approach when managing patients with thrombocytopenia in the setting of nonvariceal upper GI bleeding.

RESULTS

Eighteen of 803 potential articles were selected and reviewed, including 4 randomized controlled trials and 6 cohort studies. The only empirical clinical data available pertained to the management of hematology or oncology patients. There was no high-level evidence that determined the proper threshold of platelet transfusion specifically in GI bleeding. We were, therefore, limited to include principally consensus opinions, recommendations, and guidelines for platelet transfusion trigger as they apply to the treatment (including prophylaxis) of bleeding in general, with a paucity of data addressing major bleeding, let alone bleeding from a gastroenterologic origin. Randomized clinical trials were individually underpowered in allowing definitive conclusions, even though resulting recommendations were supported by similarly underpowered retrospective and prospective observational studies.

CONCLUSIONS

There exist a paucity of data to recommend optimal therapeutic platelet count targets in patients with active GI bleeding. Based principally on expert opinion recommendations, we propose a count of 50×10/L. Some professional associations have suggested in very specific clinical settings (postcardiopulmonary bypass surgery or central nervous system trauma) a higher value of up to 100×10/L. Properly designed randomized trials are required to more precisely address this important clinical question.

Gastrointestinal bleeding

Gastrointestinal bleeding is a common complaint encountered in the emergency department and frequent cause of hospitalization. Important diagnostic factors that increase morbidity and mortality include advanced age, serious comorbid conditions, hemodynamic instability, esophageal varices, significant hematemesis or melena, and marked anemia. Because gastrointestinal bleeding carries a 10% overall mortality rate, emergency physicians must perform timely diagnosis, aggressive resuscitation, risk stratification, and early consultation for these patients.

Thrombotic thrombocytopenic purpura and systemic lupus erythematosus: successful management of a rare presentation

Thrombotic thrombocytopenic purpura (TTP) and systemic lupus erythematosus (SLE) very rarely present simultaneously and pose a diagnostic and therapeutic dilemma to the critical care team. Prompt diagnosis and management with plasma exchange and immunosuppression is life-saving. A patient critically ill with TTP and SLE, successfully managed in the acute period of illness with plasma exchange, steroids and mycophenolate mofetil is described.

Therapeutic endoscopy for acute upper gastrointestinal bleeding

Endoscopy is the primary diagnostic and therapeutic tool for upper gastrointestinal bleeding (UGIB). The performance of endoscopic therapy depends on findings of stigmata of recent hemorrhage (SRH). For peptic ulcer disease-the most common etiology of UGIB-endoscopic therapy is indicated for findings of major SRH, such as active bleeding, oozing, or the presence of a nonbleeding visible vessel, but not indicated for minor SRH, such as a pigmented flat spot or a simple ulcer with a homogeneous clean base. Endoscopic therapies include injection, ablation, and mechanical therapy. Monotherapy reduces the risk of rebleeding in patients with peptic ulcer disease with major SRH to about 20%. Combination therapy, especially injection followed by either ablation or mechanical therapy, is generally recommended to further reduce the risk of rebleeding to about 10%. Endoscopic dual hemostasis by an experienced endoscopist reduces the risk of rebleeding, the need for surgery, the number of blood transfusions required, and the length of hospital stay. This Review article comprehensively analyzes the principles, indications, instrumentation, techniques, and efficacy of endoscopic hemostasis.

Initial management of acute upper gastrointestinal bleeding: from initial evaluation up to gastrointestinal endoscopy

Acute upper gastrointestinal bleeding is a relatively common, potentially life-threatening medical emergency responsible for more than 300,000 hospital admissions and about 30,000 deaths per annum in America. The initial assessment focuses on bleeding activity, bleeding severity, hemodynamic compromise from the bleeding, and differentiating upper from lower gastrointestinal bleeding. The initial supportive therapy includes fluid resuscitation to reverse the hypovolemia, blood transfusions to replete the lost blood, respiratory support as necessary, and proton pump inhibitor therapy to stabilize mucosal blood clots and promote hemostasis. Esophagogastroduodenoscopy is the best test to determine the bleeding site and cause.

Brief review: Coronary drug-eluting stents and anesthesia

PURPOSE

Anesthesiologists managing patients with drug-eluting stents (DES) face the challenge of balancing the risks of bleeding vs perioperative stent thrombosis (ST). This article reviews DES and the influence of antiplatelet medications related to their use. A perioperative management algorithm is suggested. Novel P2Y12 antagonists currently under investigation, including cangrelor and prasugrel are considered, as well as their potential role in modification of perioperative cardiovascular risks and management of patients with DES.

SOURCE

A PubMed search of the relevant literature over the period 1985-2005 was undertaken using the terms "drug-eluting stent", "coronary artery stent", "bare metal stent", "antiplatelet medication", "aspirin", "clopidogrel."

PRINCIPAL FINDINGS

Delayed re-endothelialization may render both sirolimus-eluting and paclitaxel-eluting stents susceptible to thrombosis for a longer duration than bare metal stents. Stent thrombosis may be associated with resistance to antiplatelet medication. In patients with a DES, a preoperative cardiology consultation is essential. Elective surgery should be postponed if the duration between DES placement and noncardiac surgery is less than six months. For semi-emergent procedures, both aspirin and clopidogrel should be continued during surgery unless clearly contraindicated by the nature of the surgery. If the risk of bleeding is high, then modification of antiplatelet medications should be considered on a case-by-case basis.

CONCLUSION

A profound increase in the number of patients with DES requires anesthesiologists to be familiar with their associated antiplatelet medications, and strategies for risk modification of ST and possible hemorrhagic complications in the perioperative setting.

Transfusion management strategies: a survey of practicing pediatric hematology/oncology specialists

BACKGROUND

Little is known about the criteria used by pediatric oncologists for the transfusion of red blood cells and platelets to pediatric oncology patients.

PROCEDURE

Data regarding red blood cell and platelet transfusion practices were collected with an internet-based survey of physician members of the American Society for Pediatric Hematology/Oncology (ASPH/O). Respondents were asked to define platelet and red blood cell transfusion thresholds in a variety of clinical scenarios, and to describe criteria for dealing with cytomegalovirus (CMV) transmission from blood products, platelet dosing strategies, and prevention of RhD alloimmunization.

RESULTS

The overall response rate was 31.4% (264 of 841). Of the respondents, 76% indicated that their institution had defined criteria for acceptable transfusion practice; of these respondents, 114 (57%) indicated that there were special guidelines for pediatric oncology patients. Examination of the distribution of threshold platelet counts and hemoglobin levels that would prompt transfusion indicated a wide range of transfusion practice in commonly encountered clinical scenarios. Similar variability in practice was evident in platelet dosing strategies, CMV prevention strategies, and in the use of anti-D in RhD-negative patients who received RhD-positive platelets.

CONCLUSIONS

This current survey demonstrates that transfusion practices vary widely among pediatric hematology/oncology specialists and that prospective clinical trials may be necessary to determine optimal criteria for blood product support in pediatric oncology patients.

Perioperative platelet transfusion: recommendations of the Agence française de sécurité sanitaire des produits de santé (AFSSaPS) 2003

PURPOSE

To present the recommendations of the Agence Française de Sécurité Sanitaire des Produits de Santé (AFSSaPS; French Safety Agency for Health Products).

METHODS

A panel of experts reviewed and graded the literature on platelet transfusions; recommendations were formulated.

MAIN FINDINGS

Threshold platelet counts (PC) for transfusions in the perioperative context have not been clearly defined and should be determined by the existence of hemorrhagic risk factors. In the case of commonly practiced invasive procedures, the recommendation is to transfuse in order to achieve PC > 50,000xmicroL(-1). In the absence of platelet dysfunction, regardless of the type of surgery, the standard hemorrhagic risk threshold for surgery is 50,000xmicroL(-1). It has not been proven that the risk threshold is different according to the type of surgery. For neurosurgery and ophthalmologic surgery involving the posterior segment of the eye, a PC of 100,000xmicroL(-1) is required. For axial regional anesthesia, a PC of 50,000xmicroL(-1) is sufficient for spinal anesthesia; a PC of 80,000xmicroL(-1) has been proposed for epidurals. During massive transfusion, prophylactic platelet infusion cannot be recommended beyond a loss of two blood volumes in less than 24 hr (Professional Consensus). As for the therapeutic transfusion of plasma and/or platelets, as much as possible, platelet deficit should be documented with test results (PC and fibrinogen) before transfusing. In the event of bleeding, platelet transfusion may precede plasma infusion. However, although this recommendation has been the subject of several professional consensus agreements, it is not based on any randomized studies.

CONCLUSION

Threshold PC for perioperative transfusions have not been clearly defined and most recommendations are the result of a professional consensus.

Epitheliotrophic capacity of a growth factor preparation produced from platelet concentrates on corneal epithelial cells: a potential agent for the treatment of ocular surface defects?

BACKGROUND

Topical application of serum eye drops has been reported to accelerate healing of persistent ocular surface defects. It is supposed that growth factors in serum support the wound healing process. Platelets (PLTs) are rich in growth factors and easily available as PLT concentrates (PCs) from blood banks. Therefore, growth factor preparations from PCs may serve as a new and superior therapeutic agent for such defects.

STUDY DESIGN AND METHODS

After thrombin stimulation for growth factor release, the cell-free supernatant (PLT releasate) of washed PCs (n = 8) was analyzed for epitheliotrophic factors and its wound healing capacity in comparison to serum (n = 8). Human corneal epithelial cells were used as a model to investigate cell growth, migration, and differentiation in response to both blood products.

RESULTS

PLT releasate contains more epithelial growth factor, PLT-derived growth factor, and transforming growth factor-beta, but less hepatocyte growth factor, fibronectin, and vitamins. Cell growth was significantly better in response to PLT releasate. Migration and differentiation were slightly better supported by serum.

CONCLUSION

Possibly owing to its high content of growth factors, PLT releasate has a distinct superior effect on cell growth. Stimulation of migration and differentiation was slightly inferior but still acceptable. PLT releasate could therefore be a novel treatment option for ocular surface defects.

Prophylactic platelet transfusion for haemorrhage after chemotherapy and stem cell transplantation

BACKGROUND

Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in thrombocytopenic patients with bone marrow failure. Although considerable advances have been made in platelet transfusion therapy in the last 30 years, some areas continue to provoke debate, especially the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding.

OBJECTIVES

To determine the optimal use of platelet transfusion for the prevention of haemorrhage (prophylactic platelet transfusion) in patients with haematological malignancies undergoing chemotherapy or stem cell transplantation.

SEARCH STRATEGY

Randomised controlled trials (RCTs) were searched for in the Cochrane Central Register of Controlled Trials (CENTRAL). Searching was also undertaken on the OVID versions of MEDLINE and EMBASE using an RCT search filter strategy.

SELECTION CRITERIA

Randomised controlled trials involving transfusions of platelet concentrates, prepared either from individual units of whole blood or by apheresis, and given prophylactically to prevent bleeding in patients with haematological malignancies and receiving treatment with chemotherapy and/or stem cell transplantation.

DATA COLLECTION AND ANALYSIS

All electronically derived citations and abstracts of papers identified by the review search strategy were initially screened for relevancy by one reviewer. Studies clearly irrelevant were excluded at this stage. The full text of all potentially relevant trials was then formally assessed for eligibility by two reviewers independently. Two reviewers completed data extraction independently. Missing data were requested from the original investigators, as appropriate. Disagreements were resolved by discussion with the other reviewers.

MAIN RESULTS

Eight completed published trials, with a total of 390 participants in the intervention groups and 362 participants in the control groups, were included in the review for further analysis. The eight studies were classified as: * three trials relevant to prophylactic platelet transfusions versus therapeutic platelet transfusions; * three trials relevant to prophylactic platelet transfusion with one trigger level versus prophylactic platelet transfusion with another trigger level; * two trials relevant to prophylactic platelet transfusion with one dose schedule versus prophylactic platelet transfusion with another dose schedule. The few reports of controlled trials addressing prophylactic versus therapeutic transfusions contained small numbers of patients and were all undertaken over 25 years ago. None of these three studies explicitly clarified whether the lack of a reported difference was a reflection of insufficient power in the trials. The findings of the meta-analyses for this group of three small studies must be interpreted with caution. In contrast, more contemporary trials addressed the question of what platelet count thresholds should apply for prophylactic transfusion; three identified studies broadly compared platelet transfusion thresholds of 10 versus 20 x 109/litre for different clinical groups of patients. There were no statistically significant differences between the groups with regards to mortality, remission rates, number of participants with severe bleeding events or red cell transfusion requirements. However, it was unclear whether the studies had sufficient power to demonstrate in combination non-inferiority in terms of safety of the lower threshold, 10 x 109/litre. Insufficient randomised trials have been undertaken to make clinically relevant conclusions about the effect of different platelet doses.

REVIEWERS' CONCLUSIONS

There are no reasons to change current practice but uncertainty about the practice of prophylactic transfusion therapy should be recognised, particularly in the light of concerns about the scenario that blood products, including platelets, could become an increasingly scarce resource in the future and for which adequate alternatives do not exist. Consideration should be given to developing adequately powered trials comparing strategies of prophylaxis versus therapeutic platelet transfusion.

Gastrointestinal hemorrhage: is the surgeon obsolete?

The management of GI hemorrhage has undergone tremendous evolution in recent decades. Once commonly managed by surgeons, the almost continuous introduction of new technologies and pharmacotherapies has dramatically improved clinicians' ability to identify and control sources of bleeding without surgery. Although a gastroenterologist can successfully manage most cases of GI hemorrhage endoscopically, surgical consultation remains an important consideration for the emergency physician in selected cases.

Critical issues in hematology: anemia, thrombocytopenia, coagulopathy, and blood product transfusions in critically ill patients

Systematic evaluations of anemia, thrombocytopenia, and coagulopathy are essential to identifying and managing their causes successfully. In all cases, clinicians should evaluate RBC measurements alongside WBC and platelet counts and WBC differentials. Multiple competing factors may coexist; certain factors affect RBCs independent of those that affect WBCs or platelets. Ideally, clinicians should examine the peripheral blood smear for morphologic features of RBCs, WBCs, and platelets that provide important clues to the cause of the patient's hematologic disorder. Thrombocytopenia arises from decreased platelet production, increased platelet destruction, or dilutional or distributional causes. Drug-induced thrombocytopenias present diagnostic challenges, because many medicines can cause thrombocytopenia and critically ill patients often receive multiple medications. If they suspect type II HIT, clinicians must promptly discontinue all heparin sources, including LMWHs, without awaiting laboratory confirmation, to avoid thrombotic sequelae. Because warfarin anticoagulation induces acquired protein C deficiency, thereby exacerbating the prothrombotic state of type II HIT, warfarin should be withheld until platelet counts increase to more than 100,000/microL and type II HIT is clearly resolving. The presence of a consumptive coagulopathy in the setting of thrombocytopenia supports a diagnosis of DIC, not TTP-HUS, and is demonstrated by decreasing serum fibrinogen levels, and increasing TTs, PTs, aPTTs, and fibrin degradation products. Increasing D-dimer, levels are the most specific DIC parameter and reflect fibrinolysis of cross-linked fibrin. Elevated PTs or a PTTs can result from the absence of factors or the presence of inhibitors. Clinicians should suspect factor inhibitors when the prolonged PT or aPTT does not correct or only partially corrects following an immediate assay of a 1:1 mix of patient and normal plasma. In addition to factor inhibitors, antiphospholipid antibodies (e.g., lupus anticoagulant) can produce a prolonged aPTT that does not correct with normal plasma but is overcome by adding excess phospholipid or platelets. Paradoxically, a tendency to thrombosis, not bleeding, accompanies lupus anticoagulants and the antiphospholipid antibody syndrome. Transfusion of red blood cells, platelets, or plasma products is sometimes warranted, but clinicians must carefully weigh potential benefits against known risks. In critically ill patients, administering RBCs can enhance oxygen delivery to tissues. Among euvolemic patients who do not have ischemic heart disease, guidelines recommend a transfusion threshold of HGB levels in the range of 6.0 to 8.0 g/dL; patients who have HGB that is at least 10.0 g/dL are unlikely to benefit from blood transfusion. The use of rHuEPO to increase erythropoiesis offers an alternative to RBC transfusion, assuming normal, responsive progenitor cells and adequate iron, folate, and cobalamin stores. Future research should examine whether clinical outcomes from rHuEPO use in critically ill patients are important and cost-effective. Because platelets play an instrumental role in primary hemostasis, platelet transfusions are often important in managing patients who are bleeding or at risk of bleeding with thrombocytopenia or impaired platelet function. Platelet transfusions carry risks, and decisions to transfuse platelets must consider clinical circumstances. Most important, platelet transfusions are generally contraindicated if the underlying disorder is TTP or type II HIT, because platelet transfusion in these settings may fuel thrombosis and worsen clinical signs and symptoms. Plasma products can correct hemostasis when bleeding arises from malfunction, consumption, or underproduction of plasma coagulation proteins. Choice of plasma product for transfusion depends on clinical circumstances. FFP is the most commonly used plasma product to correct clotting factor deficiencies, particularly coagulopathies that are attributable to multiple clotting factor deficiency states as in liver disease, DIC, or warfarin anticoagulation. PCC or rFVIIa that is administered in small volumes may provide advantages over FFP when coagulopathies require quick reversal without risk of volume overload. Factor concentrates can replace specific factor deficiencies. Recombinant FVIIa bypasses inhibitors to factors VIII and IX and vWF. Use of rFVIIa in managing hemostatic abnormalities from severe liver dysfunction; extensive surgery, trauma, or bleeding; excessive warfarin anticoagulation; and certain platelet disorders requires further study to determine optimal and cost-effective dosing regimens. Recombinant activated protein C reduces mortality from severe sepsis that is associated with organ dysfunction in adults who are at high risk for death (APACHE scores of at least 25). In severe sepsis, levels of protein C decrease, as do fibrinogen and platelet levels. Because of its anticoagulant effect, however, drotrecogin alfa may induce bleeding. Guidelines for drotrecogin alfa use must take into account bleeding risks.

The frequency of bleeding complications in patients with haematological malignancy following the introduction of a stringent prophylactic platelet transfusion policy

Indications for platelet transfusion remain controversial and are frequently based on arbitrary numerical criteria. In October 2000, we introduced a stringent prophylactic-platelet transfusion policy < 10 x 109/l for stable patients and < 20 x 10(9)/l in the presence of major bleeding or additional risk factors. A trigger of < 50 x 10(9)/l was introduced for patients undergoing invasive procedures. A prospective analysis was performed measuring the frequency of minor and major bleeding events, morbidity, mortality and duration of pancytopenia. Blood product usage was assessed and health care savings measured. A total of 98 patients were evaluated on 2147 patient study days and 271 bleeding episodes were recorded. Major bleeding occurred on 1.39% (30/2147) of the study days when platelet counts were < 10 x 10(9)/l and 2.3% (50/2147) of the study days when platelet counts were 10-20 x 10(9)/l. In patients with platelets > 20 x 10(9)/l, there were 117 major bleeding episodes observed on 5.4% of the study days. In patients with no identified additional risk factors present, major haemorrhages were recorded in 0.51% (11/2147) of the study days in patients with platelet counts > or = 10 x 10(9)/l . There was a 36% reduction in platelet units transfused compared with retrospective data when an arbitrary transfusion trigger of 20 x 10(9)/l was in place (P = < 0.02). Of note, a 16% reduction in red cell transfusions was recorded. These data confirm that the introduction of a transfusion trigger of < 10 x 10(9)/l in the absence of fresh bleeding and sepsis (> 38 degrees C) is safe and has a significant impact on overall hospital transfusion costs.

What is the proper threshold for platelet transfusion in patients with chemotherapy-induced thrombocytopenia?

Platelet transfusion therapy is an integral part of modern oncological practice and is used to treat hemorrhage associated with thrombocytopenia. More commonly, platelets are transfused to prevent hemorrhage in thrombocytopenic patients. Conventional wisdom has suggested a threshold for prophylactic transfusion of <20x10(9)/l. Many studies now support the safety of more conservative transfusion regimes that reduce patient exposure to donors and conserve precious resources, without an increase in risk of hemorrhage. This review presents the data to support the use of a prophylactic transfusion threshold of <10x10(9)/l in patients without risk factors for hemorrhage and who have ready access to emergent medical care.

Different preparation methods to obtain platelet components as a source of growth factors for local application

BACKGROUND

Autologous platelet components were recently used as part of tissue-engineering strategies in oral and maxillofacial surgery. Various preparation methods were investigated to define standardized blood bank components and to collect data on the growth factor content of human platelets before and after storage.

STUDY DESIGN AND METHODS

Apheresis platelets (AP), buffy coat-derived platelets (BCP), platelets prepared by tube method (TP), and highly concentrated samples prepared from AP and from BCP were evaluated for standard quality criteria of platelet components and for their concentration of transforming growth factor (TGF)-ss1, platelet-derived growth factor (PDGF)-AB, and PDGF-BB. AP were stored for 5 days. On Days 3 and 5, these components and freshly prepared, highly concentrated samples were evaluated for the same measures.

RESULTS

Platelet concentration in TP was lower than that in the other groups (p<0.05). However, the concentrations of PDGF-AB, PDGF-BB, and TGF-ss1 were comparable in the three groups. TP showed higher spontaneous CD62 expression than did AP and BCP. The three preparation procedures resulted in significantly different WBC contamination, with the highest levels in TP. For the whole series of measurements, there was a strong correlation between growth factor levels and platelet concentration (p<0.05), which was due to the face that the growth factor content of concentrated platelet samples was tenfold that of AP, BCP, and TP. In TP, the WBC concentration was correlated with PDGF levels (p<0.05). After 5-day storage, the mean levels of PDGF-AB, PDGF-BB, and TGF-ss1 were 57.1, 43.0, and 72.0 percent of the initial values in AP. Overall, multiple regression analysis revealed the following factors influencing the measured growth factor concentrations: platelet concentration, baseline CD62 expression, lactate production, and WBC contamination.

CONCLUSION

Various methods enable the preparation of platelet components and of highly concentrated components for local use according to standard blood banking criteria. The obtained components differ, particularly in their WBC content and in vitro platelet activation. These findings are relevant for planning and evaluating further studies of locally usable autologous platelet components.

Acute gastrointestinal bleeding in the intensive care unit. The intensivist's perspective

Gastrointestinal (GI) hemorrhage is a common and potentially lethal medical emergency that is a common cause for intensive care unit admission. The intensivist plays an important role as a member of the medical team managing the patient with GI bleeding who is at high risk because of severe bleeding, comorbidity, or the presence of endoscopic stigmata of recent hemorrhage. This article presents the intensivist's approach to GI hemorrhage in initial patient assessment, triage, resuscitation, specialist consultation, diagnostic evaluation, and medical therapy. This article focuses on types of GI bleeding of particular concern to the intensivist, including esophageal variceal bleeding, stress-related GI bleeding, and GI bleeding associated with myocardial infarcation.

Hematologic management of gastrointestinal bleeding

The hematologic management of gastrointestinal (GI) bleeding requires evaluation of the underlying cause of bleeding, associated diseases that can exacerbate the bleeding, and identification of related and unrelated coagulation abnormalities. Erythrocyte transfusions are given to increase oxygen carrying capacity; however, there is limited information on the level of anemia that places a patient at increased risk of adverse events after a GI bleed and when patients should receive erythrocyte transfusion. Isolated thrombocytopenia is uncommon in patients with GI bleeding, and there is little evidence documenting the degree of thrombocytopenia associated with an increased risk of bleeding. Platelets are often administered when the count is 50,000 per cu/mL in a bleeding patient. The coagulopathy of liver disease is the most common abnormality seen in the setting of GI bleeding. Fresh-frozen plasma (FFP) should be given in a dose equivalent to the underlying abnormality and the common practice of administering 2 units of FFP is often insufficient in a bleeding patient.