Prognostic value of protein C concentrations in neutropenic patients at high risk of severe septic complications

Drotrecogin alpha (activated): the treatment for severe sepsis?

Severe sepsis is common and increasing in incidence. Mortality rates remain high. Discovery of the link between the coagulation system and the inflammatory response to sepsis led to the development of drotrecogin alpha (activated). This recombinant form of the natural anticoagulant, activated protein C, was shown to reduce 28-day mortality from severe sepsis in a large, randomised, placebo-controlled, multi-centre Phase III study. Although subsequent studies have demonstrated that drotrecogin alpha (activated) is not of benefit to all patients with severe sepsis, it does reduce mortality rates in patients at a high risk of death. Drotrecogin alpha (activated) is associated with an increased risk of bleeding. Recent studies have shed light on its mode of action, which is primarily attributed today to cytoprotective effects especially on the endothelium with improved microcirculation. Ongoing studies will help define which patients are most likely to benefit, perhaps with the help of biochemical markers.

A comparative study of the protein C pathway in septic and nonseptic patients with organ failure

RATIONALE

Severe sepsis is associated with an exacerbated procoagulant state with protein C (PC) system impairment. In contrast, the inflammatory and coagulation status of nonseptic patients with organ failure (OF) is less documented.

OBJECTIVES

To compare coagulation activation, focusing on the PC system, and inflammatory status in septic and nonseptic patients with OF.

METHODS

Thirty patients with severe sepsis and 30 nonseptic patients were recruited at the onset of OF and compared with 30 matched healthy subjects. We performed an extensive analysis of the PC pathway, including plasma protein measurements and quantification of leukocyte expression of PC system receptors. In addition, we analyzed the inflammatory status, based on inflammation-related gene leukocyte expression.

MEASUREMENTS AND MAIN RESULTS

We observed coagulation activation, reflected by a similar increase in tissue factor mRNA expression, in the two patient groups when compared with the healthy subjects. Soluble thrombomodulin levels were higher in septic patients than in healthy control subjects, whereas PC, protein S, and soluble endothelial cell PC receptor levels were lower. Similar results were obtained in nonseptic patients with OF. Monocyte thrombomodulin overexpression, together with increased circulating levels of activated PC, suggests that the capacity for PC activation is at least partly preserved in both settings. No difference in the inflammatory profile was found between septic and nonseptic patients.

CONCLUSIONS

The pathogenesis of OF in critical care patients is characterized by an overwhelming systemic inflammatory response and by exacerbated coagulation activation, independently of whether or not infection is the triggering event. Clinical trial registered with www.clinicaltrials.gov (NCT 00361725).

Protein C concentrations correlate with organ dysfunction and predict outcome independent of the presence of sepsis

BACKGROUND

Characterizing the evolution of protein C concentrations in critically ill patients may help in identifying high risk groups and potential therapeutic targets. The authors investigated the time courses of protein C concentrations and their relation to the presence of sepsis, organ dysfunction/failure, and outcome.

METHODS

This observational cohort study, in a university hospital surgical intensive care unit (ICU), included 312 consecutive patients with an estimated ICU length of stay more than 48 h. Plasma protein C concentrations and parameters of organ dysfunction were measured daily until discharge or death.

RESULTS

Protein C concentrations were below the lower limit of normal in 50.6% of patients (n = 158) on admission and decreased to a nadir within 3-4 days after admission before almost normalizing by 2 weeks thereafter, irrespective of the presence of sepsis, sex, source and type of admission, and type of surgery. The minimum protein C concentration was lower in patients with severe sepsis/septic shock (n = 54) than in those with sepsis (n = 63) and those who never had sepsis (n = 195), and was negatively correlated to the maximum Sequential Organ Failure Assessment score (R = 0.345, P < 0.001). Protein C levels were lower in nonsurvivors (n = 46; 14.7%) than in survivors, especially in the first 4 days after admission. In a multivariable analysis with ICU mortality as the dependent variable, a minimum protein C concentration less than 45% was an independent risk factor for ICU death.

CONCLUSIONS

In critically ill surgical patients, protein C concentrations were generally low, associated with organ dysfunction/failure, and independently associated with a higher risk of ICU mortality.

Management of blast injuries and shock lung

PURPOSE OF REVIEW

Blast injuries have always occurred both in civilian life and as acts of war or terrorism. Nowadays, the risk of being involved in an explosion has increased even for those living in countries with no previous experience of such events. It is our intention that this review is of assistance to those providing emergency/critical care to patients who have sustained blast injuries.

RECENT FINDINGS

Exposure to blast may indirectly produce physiological insults such as bradycardia, hypotension, tissue hypoxia and oxidative stress. The use of early goal-directed therapy might be important in minimizing such insults. Explosions in an enclosed environment are associated with increased risk of pulmonary blast injury and also air and fat embolism. Mechanical ventilation after pulmonary blast injury is associated with barotrauma and the use of lung protective strategies previously recommended in acute lung injury may be beneficial.

SUMMARY

The potential for blast to cause injury depends on the nature of the explosive and environment in which the blast occurs. Soft tissue injury with environmental contamination is frequent. Optimal antimicrobial cover and strategies such as selective digestive decontamination may be advantageous. Early surgery should follow the principles of 'damage control'. Blast injury often leads to severe sepsis/systemic inflammatory response, multiple organ dysfunction and prolonged critical illness. In this clinical scenario, recent studies have shown improved outcome with the use of activated protein C, steroid replacement and aggressive control of blood glucose but have been less convincing regarding the use of immuno-nutrition.

Emerging role of anticoagulants and fibrinolytics in the treatment of acute respiratory distress syndrome

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are associated with high mortality rates despite therapeutic advances. The pathogenesis of ALI and ARDS is similar to that of sepsis, as these disease states involve uncontrolled host defense responses that lead to inflammation, endothelial damage, enhanced coagulation, diminished fibrinolysis, and fibroproliferation. Recent studies of anticoagulants have shown positive outcomes in patients with severe sepsis. In addition, emerging evidence suggests that the use of anticoagulants, such as tissue factor pathway inhibitor, antithrombin, thrombomodulin, heparin, activated protein C, and fibrinolytics (plasminogen activators and particularly tissue plasminogen activator), may be useful in the treatment of ALI and ARDS. Data from experimental models of sepsis, ALI, and ARDS indicate that some of these agents improve lung function and oxygenation. Although clinical data are less convincing than these findings, results from clinical trials may influence the design of future studies.

Role of protein C in renal dysfunction after polymicrobial sepsis

Protein C (PC) plays an important role in vascular function, and acquired deficiency during sepsis is associated with increased mortality in both animal models and in clinical studies. This study explored the consequences of PC suppression on the kidney in a cecal ligation and puncture model of polymicrobial sepsis. This study shows that a rapid drop in PC after sepsis is strongly associated with an increase in blood urea nitrogen, renal pathology, and expression of known markers of renal injury, including neutrophil gelatinase-associated lipocalin, CXCL1, and CXCL2. The endothelial PC receptor, which is required for the anti-inflammatory and antiapoptotic activity of activated PC (APC), was significantly increased after cecal ligation and puncture as well as in the microvasculature of human kidneys after injury. Treatment of septic animals with APC reduced blood urea nitrogen, renal pathology, and chemokine expression and dramatically reduced the induction of inducible nitric oxide synthase and caspase-3 activation in the kidney. The data demonstrate a clear link between acquired PC deficiency and renal dysfunction in sepsis and suggest a compensatory upregulation of the signaling receptor. Moreover, these data suggest that APC treatment may be effective in reducing inflammatory and apoptotic insult during sepsis-induced acute renal failure.

Drotrecogin alfa (activated) in the treatment of severe sepsis

Severe sepsis is a common and frequently fatal condition. Evidence showing a link between the coagulation system and the inflammatory response to sepsis led to the development of drotrecogin alfa (activated) as an agent in the treatment of severe sepsis. Recent studies have shown that the mode of action is actually more complex than initially thought. This recombinant form of the natural anticoagulant, activated protein C, has been demonstrated to reduce mortality in a large randomized controlled, Phase III study involving 1690 patients, even though the results of this and subsequent studies and the licensing of drotrecogin alfa (activated) have generated considerable debate. Administration of drotrecogin alfa (activated) is associated with an increased risk of bleeding and its use is contraindicated in patients with a high risk of bleeding or recent hemorrhagic events.

Levels of protein C and activated protein C: what do they mean?

Acute pancreatitis is a local inflammatory process that leads to a systemic inflammatory response in the majority of cases, and sometimes leads to multiple organ failure. It is obvious that coagulation and especially the protein C system are involved in this disease. The present commentary is related to a study in patients with pancreatitis with and without multiple organ failure in which protein C and activated protein C levels were studied. The protein C system and other studies analyzing (activated) protein C levels are discussed.

Upregulated but insufficient generation of activated protein C is associated with development of multiorgan failure in severe acute pancreatitis

INTRODUCTION

Disturbed protein C (PC) pathway homeostasis might contribute to the development of multiple organ failure (MOF) in acute pancreatitis (AP). We therefore evaluated circulating levels of PC and activated protein C (APC), evaluated monocyte deactivation in AP patients, and determined the relationship of these parameters to MOF.

PATIENTS AND METHODS

Thirty-one patients in the intensive care unit were categorized as cases (n = 13, severe AP with MOF) or controls (n = 18, severe AP without MOF). Blood samples were drawn every second day to determine the platelet count, the levels of APC, PC, and D-dimer, and the monocyte HLA-DR expression using flow cytometry. The APC/PC ratio was used to evaluate turnover of PC to APC.

RESULTS

During the initial two weeks of hospitalization, low PC levels (<70% of the adult mean) occurred in 92% of cases and 44% of controls (P = 0.008). The minimum APC level was lower in cases than in controls (median 85% versus 97%, P = 0.009). Using 87% as the cut-off value, 8/13 (62%) cases and 3/18 (17%) controls showed reduced APC levels (P = 0.021). A total of 92% of cases and 50% of controls had APC/PC ratios exceeding the upper normal limit (P = 0.013). Plasma samples drawn before MOF showed low PC levels and high APC/PC ratios. HLA-DR-positive monocytes correlated with PC levels (r = 0.38, P < 0.001) and APC levels (r = 0.27, P < 0.001), indicating that the PC pathway was associated with systemic inflammation-triggered immune suppression.

CONCLUSION

PC deficiency and decreased APC generation in severe AP probably contributed to a compromised anticoagulant and anti-inflammatory defence. The PC pathway defects were associated with the development of MOF. The data support feasibility of testing the use of APC or PC to improve the clinical outcome in AP.

Markers for sepsis diagnosis: what is useful?

Timely diagnosis of the different severities of septic inflammation is potentially lifesaving because therapies that have been shown to lower mortality should be initiated early. Sepsis and severe sepsis are accompanied by clinical and laboratory signs of systemic inflammation but patients with inflammation caused by noninfectious causes may present with similar signs and symptoms. It is important to identify markers for an early diagnosis of sepsis and organ dysfunction. This article presents currently interesting sepsis biomarkers. Other novel markers and their potential role are discussed.

Protein C concentrations in severe sepsis: an early directional change in plasma levels predicts outcome

INTRODUCTION

Protein C, because of its central role in hemostasis, plays an integral role in the host response to infection. Protein C depletion, resulting from increased consumption, degradation, and/or decreased synthesis, is characteristic of sepsis and has been shown to predict morbidity and mortality. The objective of this study was to determine whether early directional changes in protein C levels correlate with outcome.

METHODS

Patients in the Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) clinical trial were assessed and categorized by baseline protein C (n = 1574). Deficiency was categorized as: severe deficiency, protein C levels < or = 40% of normal protein C activity (n = 615, 39% of patients); deficient, protein C levels 41-80% of normal protein C activity (n = 764, 48.5% of patients); and normal, >80% of normal protein C activity (n = 195, 12.4% of patients). Logistic regression analysis of 28-day mortality for placebo patients was used to investigate whether baseline and day 1 protein C levels were independent risk factors for mortality. The impact of treatment with drotrecogin alfa (activated) (DrotAA) was also assessed.

RESULTS

Protein C levels at baseline and day 1 were independent risk factors in placebo patients. If baseline protein C levels of severely deficient placebo patients remained < or = 40% at day 1 their odds of death increased (odds ratio = 2.75, P < 0.0001), while if levels improved to >40% by day 1 their risk of death decreased (odds ratio = 0.43, P = 0.03). If baseline protein C levels of placebo patients were >40% but decreased by > or = 10% on day 1, their risk of death increased (odds ratio = 1.87, P = 0.02). DrotAA treatment improved protein C levels by day 1 compared with placebo (P = 0.008) and reduced the risk of death in severely deficient (< or = 40%) patients at baseline. Treatment also decreased the number of severely protein C deficient (= 40%) patients and decreased the number of deficient (41-80%) patients and normal (>80%) patients who had a > or = 10% decrease in protein C levels by day 1.

CONCLUSION

Baseline protein C levels were an independent predictor of sepsis outcome. Day 1 changes in protein C, regardless of baseline levels, were also predictive of outcome. The association of DrotAA treatment, increased protein C levels, and improved survival may partially explain the mechanism of action.

Treatment of adult patients with sepsis-induced coagulopathy and purpura fulminans using a plasma-derived protein C concentrate (CeprotinR)

BACKGROUND AND OBJECTIVES

The aim of this study was to document the effects of supplementation with a plasma-derived protein C concentrate in adult patients with infectious purpura fulminans.

MATERIALS AND METHODS

We report the effect of the administration of a human protein C concentrate (Ceprotin, Baxter, Vienna, Austria) in eight adult patients with purpura fulminans. Five patients received the concentrate as level-adjusted continuous infusion (10 U/kg/h, target protein C activity 100%) and three patients received the concentrate as bolus infusions (100 U/kg every 6 h) in addition to standard sepsis therapy. Heparin, fresh-frozen plasma, antithrombin- and fibrinogen concentrates, low-dose rtPA, and platelet transfusions were given when appropriate.

RESULTS

Six patients had overt disseminated intravascular coagulation: platelets, 19 g/l; fibrinogen, 60 mg/dl; antithrombin, 47%; prothrombin time, 32%; activated partial thromboplastin time (APTT), 88 s; d-dimer, 66 microg/ml; protein C activity, 29% (medians). Five patients had septic shock, six renal failure and four respiratory failure. Patients received between 5000 and 77,000 U of protein C concentrate over 2.5 days (median); the protein C activity increased to 184% (median) and coagulopathy resolved within 3 days in seven of the eight patients. Six patients survived, one died early from fulminant sepsis, and one died after 14 days from candida sepsis.

CONCLUSIONS

Our data suggest that treatment with a plasma-derived protein C zymogen concentrate might be a useful support in adult patients with purpura fulminans.

Endocrine markers of severity and prognosis in critical illness

The cellular processes that unfold in critical illness involve a variety of circulating substances, that may provide clinically relevant insight into the severity and outcome. Among hormonal markers, cortisol, several thyroid-related substances, as well as natriuretic peptides are discussed in this review. Glucose and lipids constitute metabolic markers, the identification and treatment of the former has been of particular importance. Among immune markers, both proinflammatory and anti-inflammatory cytokines, such as interleukin-6, contribute essential prognostic information. Finally, the complement and coagulation pathways also provide unique insight into this complex and heterogeneous process.

FoxA2 involvement in suppression of protein C, an outcome predictor in experimental sepsis

Low levels of protein C (PC) predict outcome as early as 10 h after insult in a rat polymicrobial sepsis model and were associated with suppression of PC mRNA, upstream transcription factor FoxA2, and cofactor hepatocyte nuclear factor 6 (HNF6). Small interfering RNA suppression of FoxA2 in isolated hepatocytes demonstrated regulation of both its cofactor HNF6 and PC. Our data suggest that reduced FoxA2 may be important in the suppression of PC and resulting poor outcome in sepsis.

Use of Drotrecogin Alpha (Recombinant Human Activated Protein C, rhAPC) in the Treatment of Severe Sepsis Induced by Graft Pancreatitis After Simultaneous Pancreas and Kidney Transplantation: A Case Report

We present our experience with recombinant human activated protein C (rhAPC) to treat a 40-year-old preemptive simultaneous pancreas-kidney transplant (spktx) recipient who developed septic shock due to graft pancreatitis. We diagnosed intra-abdominal septic complications with septicemia induced by multiple pathogens and cardiopulmonary insufficiency. Until the 59th posttransplant day, 21 peritoneal lavages were performed to treat peritonitis and intra-abdominal abscesses. On the 53rd day when septic shock was diagnosed, rhAPC was administered, after which the patient improved, vasoconstrictive agents were reduced, and respiratory insufficiency resolved. The Physiologic and Operative Severity Score for enumeration of Mortality and Morbidity (POSSUM) scale showed a decrease in predicted mortality from 93% to 17% on day 7 after rhAPC initiation. The patient was discharged at 128 days after spktx with good function of both grafts. Administration of rhAPC limited systemic inflammatory response syndrome (SIRS) and may be considered when faced with the dilemma of stopping immunosuppression to save a recipient's life but at the cost of rejection of a functioning graft.

Animal models of sepsis: setting the stage

Sepsis is a state of disrupted inflammatory homeostasis that is often initiated by infection. The development and progression of sepsis is multi-factorial, and affects the cardiovascular, immunological and endocrine systems of the body. The complexity of sepsis makes the clinical study of sepsis and sepsis therapeutics difficult. Animal models have been developed in an effort to create reproducible systems for studying sepsis pathogenesis and preliminary testing of potential therapeutic agents. However, demonstrated benefit from a therapeutic agent in animal models has rarely been translated into success in human clinical trials. This review summarizes the common animal sepsis models and highlights how results of recent human clinical trials might affect their use.

Early and innovative interventions for severe sepsis and septic shock: taking advantage of a window of opportunity

The pathogenic, diagnostic and therapeutic landscape of sepsis is no longer confined to the intensive care unit: many patients from other portals of entry to care, both outside and within the hospital, progress to severe disease. Approaches that have led to improved outcomes with other diseases (e.g., acute myocardial infarction, stroke and trauma) can now be similarly applied to sepsis. Improved understanding of the pathogenesis of severe sepsis and septic shock has led to the development of new therapies that place importance on early identification and aggressive management. This review emphasizes approaches to the early recognition, diagnosis and therapeutic management of sepsis, giving the clinician the most contemporary and practical approaches with which to treat these patients.

Microcirculatory alterations in ischemia-reperfusion injury and sepsis: effects of activated protein C and thrombin inhibition

Experimental studies in ischemia–reperfusion and sepsis indicate that activated protein C (APC) has direct anti-inflammatory effects at a cellular level. In vivo, however, the mechanisms of action have not been characterized thus far. Intravital multifluorescence microscopy represents an elegant way of studying the effect of APC on endotoxin-induced leukocyte–endothelial-cell interaction and nutritive capillary perfusion failure. These studies have clarified that APC effectively reduces leukocyte rolling and leukocyte firm adhesion in systemic endotoxemia. Protection from leukocytic inflammation is probably mediated by a modulation of adhesion molecule expression on the surface of leukocytes and endothelial cells. Of interest, the action of APC and antithrombin in endotoxin-induced leukocyte–endothelial-cell interaction differs in that APC inhibits both rolling and subsequent firm adhesion, whereas antithrombin exclusively reduces the firm adhesion step. The biological significance of this differential regulation of inflammation remains unclear, since both proteins are capable of reducing sepsis-induced capillary perfusion failure. To elucidate whether the action of APC and antithrombin is mediated by inhibition of thrombin, the specific thrombin inhibitor hirudin has been examined in a sepsis microcirculation model. Strikingly, hirudin was not capable of protecting from sepsis-induced microcirculatory dysfunction, but induced a further increase of leukocyte–endothelial-cell interactions and aggravated capillary perfusion failure when compared with nontreated controls. Thus, the action of APC on the microcirculatory level in systemic endotoxemia is unlikely to be caused by a thrombin inhibition-associated anticoagulatory action.

Coagulopathy After Successful Cardiopulmonary Resuscitation Following Cardiac Arrest

OBJECTIVES

We investigated coagulation abnormalities in out-of-hospital cardiac arrest (OHCA) patients, with special attention to the protein C anticoagulant pathway.

BACKGROUND

Successfully resuscitated cardiac arrest is followed by a systemic inflammatory response and by activation of coagulation, both of which may contribute to organ failure and neurological dysfunction.

METHODS

Coagulation parameters were measured in all patients admitted after successfully resuscitated OHCA.

RESULTS

At admission, 67 patients had a systemic inflammatory response with increased interleukin-6 and coagulation activity (thrombin-antithrombin complex), reduced anticoagulation (antithrombin, protein C, and protein S), activated fibrinolysis (plasmin-antiplasmin complex), and, in some cases, inhibited fibrinolysis (increased plasminogen activator inhibitor-1 with a peak on day 1). These abnormalities were more severe in patients who died within two days (50 of 67, 75%) and were most severe in patients dying from early refractory shock. Protein C and S levels were low compared to healthy volunteers and discriminated OHCA survivors from nonsurvivors. Furthermore, a subgroup of patients had a transient increase in plasma-activated protein C at admission followed by undetectable levels. This, along with an increase in soluble thrombomodulin over time, suggests secondary endothelial injury and dysfunction of the protein C anticoagulant pathway similar to that observed in severe sepsis.

CONCLUSIONS

Major coagulation abnormalities were found after successful resuscitation of cardiac arrest. These abnormalities are consistent with secondary down-regulation of the thrombomodulin-endothelial protein C receptor pathway.

Protein C as an early marker of severe septic complications in diffuse secondary peritonitis

To evaluate the predictive value of protein C as a marker of severity in patients with diffuse peritonitis and abdominal sepsis, protein C levels were repeatedly determined and compared with serum levels of antithrombin III, plasminogen, alpha(2)-antiplasmin, Plasminogen activator inhibitor, D-dimer, C1-inhibitor, high molecular weight kininogen, and the C5a, C5b-9 fragments of the complement system. We carried out a prospective study from 44 patients with severe peritonitis confirmed by laparotomy and 15 patients undergoing elective ventral hernia repair who acted as controls. Analyzed biochemical parameters were determined before operations and on days 1, 2, 3, 5, 7, 10, and 14 after operations. For the study group, preoperative average protein C level was significantly lower in the patients who developed septic shock in the late course of the disease, with lethal outcome, than in the patients with severe peritonitis and sepsis who survived (p = 0.0001). In non-survivors, protein C activity remained decreased below 70%, whereas the course of survivors was characterized by increased values that were significantly higher (p < 0.03) at every time point than in those patients who died. Protein C was of excellent predictive value and achieved a sensitivity of 80% and a specificity of 87.5% in discriminating survivors from non-survivors within the first 48 hours of the study (AUC-0.917; p < 0.001), with a "cut-off" level of 66.0%. As for the control group, throughout the study period, protein C activity was permanently maintained within the range of normal, with significant differences with reference to the study group (p < 0.01). These results suggest that protein C represents a sensitive and early marker for the prediction of severe septic complications during diffuse peritonitis, and of outcome.

Association between the severity of sepsis and the changes in hemostatic molecular markers and vascular endothelial damage markers

It is well known that disorders of coagulation and fibrinolysis play a major role in the development of organ dysfunction during sepsis. Furthermore, the importance of the early initiation of anticoagulation therapy for severe cases has been emphasized based on the success of recent clinical trials. The purpose of this study is to search for useful markers for predicting organ dysfunction. Plasma samples were prospectively collected from 78 patients within 48 h after the onset of sepsis. Hemostatic markers and endothelial damage markers were compared between the patients with and without organ dysfunction. The WBC and platelet counts were not different between the groups. In contrast, fibrin/fibrinogen degradation products, D-dimer, thrombin-antithrombin complex, plasmin alpha2-antiplasmin complex, soluble fibrin, and total plasminogen activator inhibitor-1 were significantly higher, and the antithrombin activity and protein C levels were lower in the patients with organ dysfunction. Thus, the changes in the hemostatic molecular markers were associated with organ dysfunction from an early stage of sepsis, and antithrombin and protein C activities were found to be the most reliable markers.

Dynamic evolution of coagulopathy in the first day of severe sepsis: relationship with mortality and organ failure

OBJECTIVE

To determine whether changes in coagulation biomarkers during the first day of severe sepsis correlate with progression from single to multiple organ failure and subsequent death.

DESIGN

Analysis of secondary endpoints in a prospective, randomized, placebo-controlled, multinational clinical trial (PROWESS).

SETTING

The study involved 164 medical centers.

PATIENTS

A total of 840 patients who met criteria for severe sepsis and were randomized to receive placebo plus supportive care.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Coagulation biomarkers, prothrombin time, antithrombin activity, and D-dimer and protein C levels were measured, and Sequential Organ Failure Assessment was performed daily. Multiple logistic regression analysis identified baseline antithrombin activity <54% and changes in prothrombin time, D-dimer, and antithrombin activity during the first calendar day after the onset of the first sepsis-induced organ dysfunction (i.e., the first day of severe sepsis, day 1) as predictive of 28-day mortality (p < or = .01). A composite coagulopathy score was determined using points for predetermined levels of change from baseline to day 1. The composite coagulopathy score correlated with progression from single to multiple organ failure (p = .0007), time to resolution of organ failure (p = .0004), and 28-day mortality (p < .0001). Combining the composite coagulopathy score with the Acute Physiology and Chronic Health Evaluation (APACHE) II score improved ability to identify patients who would progress to multiple organ failure (area under receiver operating characteristic curve 0.61 APACHE II vs. 0.65 APACHE II + composite coagulopathy score) and who would die (area under receiver operating characteristic curve 0.69 APACHE II vs. 0.74 APACHE II + composite coagulopathy score).

CONCLUSIONS

Continuation or worsening of coagulopathy during the first day of severe sepsis was associated with increased development of new organ failure and 28-day mortality. These results further suggest that coagulation abnormalities contribute to organ failure and death.

Antithrombotic agents in the treatment of severe sepsis

Sepsis, a systemic inflammatory syndrome, is a response to infection and when associated with multiple organ dysfunction is termed severe sepsis. It remains a leading cause of mortality in the critically ill. The response to the invading microorganisms may be considered as a balance between a pro-inflammatory and an anti-inflammatory reaction. While an inadequate pro-inflammatory reaction and a strong anti-inflammatory response could lead to overwhelming infection and the death of the patient, a strong and uncontrolled pro-inflammatory response, manifested by the release of pro-inflammatory mediators may lead to microvascular thrombosis and multiple organ failure. Endotoxin triggers sepsis via the release of various mediators such as tumour necrosis factor-alpha and interleukin-1 (IL-1). These cytokines activate the complement and coagulation systems, release adhesion molecules, prostaglandins, leukotrienes, reactive oxygen species and nitric oxide. Other mediators involved in the sepsis syndrome include IL-1, -6 and -8; arachidonic acid metabolites; platelet activating factor; histamine; bradykinin; angiotensin; complement components and vasoactive intestinal peptide. These pro-inflammatory responses are counteracted by IL-10. Most of the trials targeting the different mediators of the pro-inflammatory response have failed due to a lack of correct definition of sepsis. Understanding the exact pathophysiology of the disease will enable more advanced treatment options. Targeting the coagulation system with various anticoagulant agents including, activated protein C, and tissue factor pathway inhibitor (TFPI) is a rational approach. Many clinical trials have been conducted to evaluate these agents in severe sepsis. While trials on antithrombin and TFPI were not so successful, the double-blind, placebo-controlled, Phase III trial of recombinant human activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) was successful, creating a significant decrease in mortality when compared to the placebo group. A better understanding of the pathophysiologic mechanism of severe sepsis will provide better treatment options, and combination antithrombotic treatment may provide a multipronged approach for the treatment of severe sepsis.

Management of infections in critically ill neutropenic cancer patients

Because of improving antineoplastic treatment options with increasing cure rates, prolonging survival, and improving quality of life, the reluctance to admit patients with malignant disease to an intensive care unit is not justified; thus, the number of patients with malignancies treated in intensive care units rises. The use of more aggressive anticancer regimens leads to an increase of attendant infections, which are the most frequent and often life-threatening complications in cancer patients. A multidisciplinary practical approach to evaluation and treatment is needed to optimize treatment results and to meet the various diagnostic and therapeutic challenges in this subset of patients on an intensive care unit.

Drotrecogina alfa (activada): tratamiento específico para la sepsis grave

Severe sepsis is a high prevalent disease at Intensive Care Units with no specific treatment till recently. Several clinical trials show low serum levels of activated protein C in this kind of patients. Recently, drotrecogin alfa (activated), a recombinant human activated protein C, has been approved in Spain for severe sepsis treatment in addition to the best patient care. Protein C (activated) has antithrombotic, profibrinolitic an antiinflamatory properties. So far, Prowess (phase 3 trial) is the most important clinical trial conducted with drotrecogin alfa (activated) at the moment. It demonstrates not only its efficacy and safety, but also a 19.4% reduction in the relative risk of death. Nevertheless, it is difficult to decide which patients would be candidate for this new therapy due to its lack of experience, high cost and the risk-benefit relationship. This review attempts to provide an overview about this new hospital drug.

Drotrecogin alfa: a role in emergency department treatment of severe sepsis?

Human protein C is a serine protease that circulates in the blood as an inactive zymogen. It is converted to its active form by interaction with thrombomodulin on the endothelial wall. Activated protein C has a significant role in maintaining haemostasis, and is a major mechanism of controlling microvascular thrombosis. Recent reports describe the use of drotrecogin alfa (recombinant activated protein C) in severe sepsis, a condition relevant to emergency medicine. This review describes the physiology of the protein C pathway and its importance in sepsis. It will also focus on the use of drotrecogin alfa in sepsis, and its use in the ED.

Patients with severe sepsis vary markedly in their ability to generate activated protein C

Activated protein C (APC) supplementation significantly reduces mortality in patients with severe sepsis, presumably by down-regulating coagulation, inflammation, and apoptosis. In vivo, endogenous APC is generated from protein C (PC) “on demand” in response to elevated thrombin levels. Thrombomodulin and endothelial cell protein C receptor are endothelial receptors required to generate APC endogenously. Since these receptors may be down-regulated in sepsis, we measured plasma markers of APC generation in 32 patients with severe sepsis to determine whether APC generation is impaired and whether markers of APC generation correlate with 28-day mortality. Relative to normals, all patients had elevated F1 + 2 and thrombin-antithrombin complex (TAT) levels (markers of thrombin generation and inhibition, respectively), and 28 of 32 patients had reduced PC levels. In 20 patients, APC levels paralleled elevated F1 + 2 levels, whereas 12 patients had low APC levels despite elevated F1 + 2 levels, suggesting that APC generation is impaired in the latter. No significant differences exist between survivors and nonsurvivors with respect to baseline PC levels, F1 + 2 levels, and APACHE II (acute physiology and chronic health evaluation) scores. Baseline APC levels were higher in survivors (P = .024), and baseline F1 + 2/APC ratios were lower in survivors (P = .047). Larger studies are warranted to establish whether APC generation profiles aid in managing sepsis. (Blood. 2004;104:3958-3964)

Drotrecogin alfa (activated) for the treatment of severe sepsis and septic shock

Coagulopathy and systemic inflammation are almost universal in patients with severe sepsis. Interaction between the two results in an intense inflammatory response and microthrombi formation in the vessels of multiple organs, resulting in organ dysfunction or severe sepsis. Recombinant human activated protein C, also known as drotrecogin alfa (activated), possesses anti-inflammatory, antithrombotic, and profibrinolytic properties. Treatment with drotrecogin alfa (activated) significantly reduces morbidity and mortality in patients with severe sepsis. An increased risk of bleeding during the infusion was the only side effect experienced. Recent data demonstrate that early administration of drotrecogin alfa (activated) is associated with lower mortality rates. Despite concern over its relatively high cost, analysis has demonstrated that recombinant human activated protein C is as cost-effective as other commonly used treatments in the intensive care unit.

A protein C deficiency exacerbates inflammatory and hypotensive responses in mice during polymicrobial sepsis in a cecal ligation and puncture model

During the systemic inflammatory state induced by sepsis, the potential for coagulopathy exists because of up-regulation of natural procoagulants and anti-fibrinolytics, and down-regulation of natural anti-coagulants, with protein C (PC) being a critical example of the latter case. PC functions as an anti-coagulant, profibrinolytic, and anti-inflammatory agent, and, thus, its administration or deficiency may affect the course and outcome of sepsis in patients. In this study, a cecal ligation and puncture model of septic peritonitis was applied to wild-type mice and littermates with a targeted heterozygous deficiency of PC (PC(+/-)) to characterize the importance of a PC-deficiency on polymicrobial sepsis. An enhanced mortality rate was found to accompany a PC deficiency. Plasma cytokines, as well as organ-specific expression of cytokine transcripts, were elevated in PC(+/-) mice. No signs of severe disseminated intravascular coagulation (DIC) were observed in wild-type or PC(+/-) mice, as indicated by an increase in fibrinogen levels and the invariability of platelet counts after cecal ligation and puncture. Consumption of coagulation factors was similar in both genotypes and a decrease in the PC mRNA and protein levels was more prominent in PC(+/-) mice. Renal and organ muscle damage was enhanced in PC(+/-) mice, as shown by increases in plasma blood urea nitrogen, creatinine, and creatinine kinase. Hypotension and bradycardia were more enhanced in PC(+/-) mice than in wild-type mice, thus provoking a more severe septic shock response. Thus, the hemodynamic role of PC during sepsis is of critical importance to the outcome of the disease.

Gene expression profiling of inflamed human endothelial cells and influence of activated protein C

BACKGROUND

During systemic inflammation, activation of vascular endothelium by proinflammatory cytokines leads to hypotension, microvascular thrombosis, and organ damage. Recent data suggest a link between coagulation and inflammation through the activated protein C (APC) pathway. We studied gene expression profiles in human coronary artery endothelial cells (HCAECs) exposed to proinflammatory stimuli and the influence of APC on expression of candidate genes regulated by these stimuli.

METHODS AND RESULTS

HCAECs were stimulated with interleukin-1beta, interferon-gamma, and tumor necrosis factor-alpha. In gene expression profiling, 400 of 8400 genes were regulated >2-fold. Verification of selected candidate genes was achieved by measuring expression of mRNA species by real-time polymerase chain reaction, cytokine secretion by ELISA, and metabolites of tetrahydrobiopterin (BH4) biosynthesis by high-performance liquid chromatography. BH4 synthesis, interleukin-6, interleukin-8, monocyte chemotactic protein-1 (MCP-1), and intercellular adhesion molecule-1 (ICAM-1) were downregulated by APC at the transcriptional and protein level. Endothelial nitric oxide synthase, endothelial adhesion molecule, and vascular cell adhesion molecule-1 were not affected by APC. Activities of transcription factors c-Fos, FosB, and c-Rel were inhibited by APC in inflamed HCAECs.

CONCLUSIONS

Our study revealed a novel antiinflammatory mechanism of APC-dependent gene regulation in HCAECs since c-Fos-dependent induction of MCP-1 and ICAM-1 was suppressed. APC downregulates expression and activity of genes related to inflammation, most pronounced under intermediate or mild inflammatory conditions.

[Disturbances of protein C activity in abdominal sepsis: diagnostic and predictive importance]

BACKGROUND

Despite improved diagnostic modalities, potent antibiotics, modern intensive care, and aggressive surgical treatment, more than one third of patients still die of severe secondary peritonitis. Clinical difficulties in the treatment of abdominal sepsis were related to inherent problems of limited clinical signs and the rapid spread of infection. An inflammatory process is often well under way before the presence of clinical signs and symptoms of sepsis. The aim of this prospective study was to assess diagnostic and prognostic significance of protein C in abdominal sepsis.

METHODS

Twenty-two patients with severe intraabdominal infections with sepsis syndrome were treated surgically as compared to 15 patients with hernia repair (control group). During the study, the following parameters were analyzed daily: protein C, AT III, plasminogen, alfa-2 antiplasmin, HMWK, C5a and C5-B9 complement, C1-inhibitor, CRP. RESULTS. The mean APACHE II score was 17 points, with actual mortality rate of 23%. Each parameter evaluated in the abdominal sepsis group differed from the one evaluated in the control group to a great extent (p = 0.001). The results and multivariate regression statystical analysis confirmed the following parameters as sensitive biological markers of septic cascade (p < 0.0001-0.026): protein C, AT III, HMWK, C1-inhibitor and C5-B9 complement. According to the results the low level of protein C consistently correlated with disease severity and suggested the development of septic shock and poor outcome.

CONCLUSION

Early diagnosis of plasma proteolytic disturbances was very important, from the diagnostic and predictive point of view, in abdominal sepsis. According to the results protein C was the most significant marker of sepsis and early predictor of the outcome of septic complications during severe intraabdominal infections (r = 0.761; p = 0.0001).

Evaluation of protein C and other biomarkers as predictors of mortality in a rat cecal ligation and puncture model of sepsis

OBJECTIVE

To evaluate protein C and other factors associated with the septic response as predictors of mortality in a clinically relevant animal model of sepsis.

DESIGN

Laboratory investigation.

SETTING

Eli Lilly and Company discovery research laboratory.

SUBJECTS

Forty female Sprague Dawley rats weighing 245-265 g.

INTERVENTIONS

Polyethylene catheters were surgically implanted into the femoral vein and sepsis was induced by cecal ligation and puncture (CLP). A solution of 5% dextrose in 0.9 % saline was continuously infused via femoral catheters immediately following surgery. Blood sampling was done before surgery and at 6 and 20 hrs after surgery. Rats were then monitored for survival out to 4 days.

MEASUREMENTS AND MAIN RESULTS

Blood collections were used to measure blood glucose, bacteremia, plasma protein C, D-dimer, hormones, chemokines, cytokines, and myoglobin (as a marker of organ damage). Mortality was categorized into three groups: early death (before 30 hrs post-CLP), late death (after 30 hrs post-CLP), and survivors (96 hrs post-CLP). Compared with survivors, early death rats had statistically significant differences in 30 variables indicative of severe inflammation, coagulopathy, and muscle damage including less bacterial clearance, hypoglycemia, lower plasma protein C, higher plasma D dimer, higher plasma cytokine/ chemokines, and higher plasma myoglobin concentrations. Twenty variables had a moderate to strong correlation with time of death. Receiver operator characteristic curves generated from a simple logistic regression model indicated that KC and macrophage inflammatory protein-2, rodent homologues of the human growth related oncogene CXC chemokine family, and protein C were the best predictors of mortality in this model.

CONCLUSIONS

The data from this study indicate that an early decrease in protein C concentration predicts poor outcome in a rat sepsis model. The data further indicate that increases in the CXC chemokines macrophage inflammatory protein-2 and KC precede poor outcome.

A recombinant murine meizothrombin precursor, prothrombin R157A/R268A, inhibits thrombosis in a model of acute carotid artery injury

Mutations in human prothrombin that generate a stable form of meizothrombin or meizothrombin(desF1) cause dysprothrombinemia in both the homozygous and heterozygous state, suggesting that meizothrombin has dominant anticoagulant effects in vivo. The enzymatic characterization of recombinant mouse meizothrombin, meizothrombin(desF1), and thrombin indicates that all 3 enzymes have similar activity toward the chromogenic substrate S-2238, that meizothrombin and meizothrombin(desF1) have less than 10% of the fibrinogen-clotting activity of thrombin, and that meizothrombin is more active than thrombin or meizothrombin(desF1) for thrombomodulin-dependent protein C activation. Thus, activated mouse prothrombin R157A/R268A is similar to human meizothrombin in activity toward S-2238, fibrinogen, and protein C. The time to occlusion after FeCl3-induced carotid artery injury was delayed (11.8 ± 3.6 minutes, n = 5) in Cf2+/- mice infused with prothrombin R157A/R268A compared with control mice infused with wild-type prothrombin (5.3 ± 1.5 minutes, n = 3; P = .006). In this model, prothrombin R157A/R268A has anticoagulant activity that reflects its decreased fibrinogen-clotting activity and preserved protein C-activating activity and is consistent with dominant inhibition of fibrinogen clotting. (Blood. 2004;104:415-419)

Protein C/activated protein C pathway: overview of clinical trial results in severe sepsis

OBJECTIVE

To review the results from clinical trials of treatments for severe sepsis involving the protein C/activated protein C pathway.

DATA SOURCE

Published research and review articles (PubMed, from 1985 to 2003) relating to clinical trials of compounds involving the protein C pathway.

DATA EXTRACTION AND SYNTHESIS

Protein C is converted to activated protein C when thrombin complexes with thrombomodulin. Sepsis is associated with rapid depletion of protein C and blunted endogenous protein C activation. Treatment with protein C concentrate is followed by increased activated protein C plasma levels and a dose-dependent decrease in d-dimer levels in children with purpura fulminans. This supplementation is safe. A phase III trial of recombinant human activated protein C (drotrecogin alfa [activated]) in severe sepsis demonstrated a 6.1% absolute reduction in 28-day mortality compared with placebo. The short- and long-term survival rates associated with drotrecogin alfa (activated) were better in patients at high risk of death associated with a better cost/effectiveness ratio. Treatment with drotrecogin alfa (activated) was associated with an increased risk of serious bleeding compared with placebo during the 28-day study period (3.5% vs. 2.0%).

CONCLUSIONS

Treatment with protein C concentrate is followed by an improvement of the coagulopathy and is safe in children with purpura fulminans; however, a large trial involving a high dose is required to determine its effect on mortality and morbidity. Treatment with drotrecogin alfa (activated) leads to substantial reduction in mortality and has an acceptable risk/benefit ratio in septic patients at high risk of death.

The Role of Activated Protein C in Sepsis

Sepsis is an uncontrolled, unregulated and self-sustaining intravascular inflammation that results from an imbalance between proinflammatory reaction and excessive anti-inflammatory response. It is associated with increased mortality and morbidity. The major cause of death is multiple end-organ failure that occurs secondary to disseminated intravascular coagulation. Activated protein C has anti-inflammatory, anticoagulant, and fibrinolytic activity and demonstrated a beneficial effect in reducing mortality in patients with severe sepsis. In this review, the authors evaluated the role of Activated Protein C in sepsis.

Microhemodynamic and cellular mechanisms of activated protein C action during endotoxemia

OBJECTIVE

To characterize microcirculatory actions of activated protein C in an endotoxemia rodent model that allows in vivo studies of microvascular inflammation and perfusion dysfunction.

DESIGN

Animal study using intravital microscopy.

SETTING

Animal research facility.

SUBJECTS

Male Syrian golden hamsters, 6-8 wks old with a body weight of 60-80 g.

INTERVENTIONS

In skinfold preparations, endotoxemia was induced by intravenous administration of 2 mg/kg endotoxin (lipopolysaccharide, Escherichia coli). Intravital microscopy allowed quantitative analysis of arteriolar and venular leukocyte adhesion and functional capillary density (cm) that served as a measure of microvascular perfusion failure. Activated protein C (APC group, n = 8, 24 microg/kg intravenously) was substituted continuously during 8 hrs after lipopolysaccharide, whereas endotoxemic buffer-treated animals (control, n = 7) served as controls.

MEASUREMENTS AND MAIN RESULTS

Lipopolysaccharide increased leukocyte adhesion and decreased functional capillary density to 50% of baseline values (p <.01 vs. baseline). Activated protein C treatment inhibited (p <.05) lipopolysaccharide-mediated leukocytic response and attenuated (p <.05) endotoxic perfusion failure in nutritive capillaries.

CONCLUSIONS

Activated protein C-induced protection from lipopolysaccharide-mediated microcirculatory dysfunction was characterized in vivo for the first time. The impressive modification of leukocyte cross-talk indicates systemic anti-inflammatory activated protein C effects on leukocytes and the endothelium, subsequently improving capillary perfusion. These actions could represent the in vivo mechanism of activated protein C interactions observed in patients with severe sepsis.

Endogenous protein C activation in patients with severe sepsis

OBJECTIVE

To review how endogenous protein C activation might change in disease states and to discuss the implications of these findings in the context of severe sepsis.

DATA SOURCE

A review of the published literature in PubMed together with data from abstracts from 2001 to present.

DATA EXTRACTION AND SYNTHESIS

Activated protein C (APC) supplementation has been shown to significantly reduce mortality in patients with severe sepsis, presumably by virtue of its ability to down-regulate coagulation, inflammation, and apoptosis. In vivo, endogenous APC is generated in the circulation when protein C is activated by the thrombin-thrombomodulin complex. Protein C activation is augmented by the endothelial cell protein C receptor. Thus, thrombomodulin and the endothelial cell protein C receptor are components of the endothelium-based "machinery" required for efficient activation of protein C. In healthy individuals, the amount of APC formed is proportional to thrombin levels. In vitro studies have shown that thrombomodulin and the endothelial cell protein C receptor are down-regulated by inflammatory cytokines, and the levels of these receptors are reduced in the endothelium of skin-biopsy specimens in children with severe meningococcal sepsis. However, endothelial studies of excised blood vessels provide only a partial picture of the APC pathway in vivo. Knowledge of endogenous plasma levels of protein C, thrombin, and APC may be helpful in assessing the functional status of the protein C pathway in the systemic circulation. To date, there are few reports available on endogenous APC levels in patients with severe sepsis, perhaps due to the lack of available assays that permit both rapid and accurate measurements. A unique feature of our study is that we have developed an APC assay that, for the first time, permits rapid and accurate measurements of plasma APC levels. Preliminary studies using this assay suggest that adult patients with severe sepsis vary markedly in their ability to generate APC endogenously. These results are intriguing because they suggest that, depending on individual defects in the protein C pathway, some patients have impaired protein C activation and might require APC therapy, whereas others may benefit from administration of protein C. Although the clinical efficacy of recombinant human APC (drotrecogin alfa [activated]) in severe sepsis has been reported in a phase III clinical trial, the efficacy of protein C in severe sepsis remains to be determined.

CONCLUSIONS

Preliminary results suggest that adult patients with severe sepsis vary markedly in their ability to convert endogenous protein C to APC. Additional research is required to establish whether endogenous APC activation profiles are useful in the clinical management of patients with severe sepsis.

Plasma protein C levels in patients with acute lung injury: Prognostic significance

Decreased circulating protein C is a marker of a prothrombotic state that has been associated with poor clinical outcomes in sepsis. However, protein C has not been measured in patients with acute lung injury and acute respiratory distress syndrome (ALI/ARDS). In this study, we measured circulating and intra-alveolar concentrations of protein C in 45 patients with ALI/ARDS from septic and nonseptic causes. Plasma protein C levels were lower in ALI/ARDS compared with normal controls. Lower levels of plasma protein C were associated with worse clinical outcomes, including death, fewer ventilator-free days, and more nonpulmonary organ failures, even when only patients without sepsis were analyzed. In summary, the protein C system is markedly disrupted in patients with ALI/ARDS from both septic and nonseptic causes. The protein C system may be a therapeutic target in patients with ALI/ARDS.

Universal changes in biomarkers of coagulation and inflammation occur in patients with severe sepsis, regardless of causative micro-organism [ISRCTN74215569]

INTRODUCTION

PROWESS (Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis) was a phase III, randomized, double blind, placebo controlled, multicenter trial conducted in patients with severe sepsis from 164 medical centers. Here we report data collected at study entry for 1690 patients and over the following 7 days for the 840 patients who received placebo (in addition to usual standard of care).

METHODS

Nineteen biomarkers of coagulation activation, anticoagulation, fibrinolysis, endothelial injury, and inflammation were analyzed to determine the relationships between baseline values and their change over time, with 28-day survival, and type of infecting causative micro-organism.

RESULTS

Levels of 13 of the 19 biomarkers at baseline correlated with Acute Physiology and Chronic Health Evaluation II scores, and nearly all patients exhibited coagulopathy, endothelial injury, and inflammation at baseline. At study entry, elevated D-dimer, thrombin-antithrombin complexes, IL-6, and prolonged prothrombin time were present in 99.7%, 95.5%, 98.5%, and 93.4% of patients, respectively. Markers of endothelial injury (soluble thrombomodulin) and deficient protein C, protein S, and antithrombin were apparent in 72%, 87.6%, 77.8%, and 81.7%, respectively. Impaired fibrinolysis (elevated plasminogen activator inhibitor-1) was observed in 44% of patients. During the first 7 days, increased prothrombin time (which is readily measurable in most clinical settings) was highly evident among patients who were not alive at 28 days.

CONCLUSION

Abnormalities in biomarkers of inflammation and coagulation were related to disease severity and mortality outcome in patients with severe sepsis. Coagulopathy and inflammation were universal host responses to infection in patients with severe sepsis, which were similar across causative micro-organism groups.

New approaches to the treatment of sepsis

The clinical spectrum of sepsis, severe sepsis, and septic shock is responsible for a growing number of deaths and excessive health care expenditures. Until recently, despite multiple clinical trials, no intervention provided a beneficial outcome in septic patients. Within the last 2 years, studies that involved drotrecogin alfa (activated), corticosteroid therapy, and early goal-directed therapy showed efficacy in those with severe sepsis and septic shock. These results have provided optimism for reducing sepsis-related mortality.

Drotrecogin alfa (activated; Xigris): an effective and cost-efficient treatment for severe sepsis

Severe sepsis is a common health problem with consequences for both patients and the healthcare system. Over the past 20 years, multiple immunomodulatory agents have been investigated in an unsuccessful attempt to decrease the morbidity and mortality of severe sepsis. Drotrecogin alfa (activated; Xigris) may represent a breakthrough in the treatment of sepsis. It has been demonstrated to have beneficial effects in decreasing biological markers of the severity of sepsis in preclinical and Phase II studies. A single, large Phase III trial has demonstrated the efficacy of drotrecogin alfa (activated) in a sample of patients with severe sepsis. This sample appears to be comparable with the general population of patients with severe sepsis. Three separate economic analyses have shown drotrecogin alfa (activated) to have a cost-utility ratio similar to other therapies that are currently funded, when used for the treatment of the most severely ill group of patients. This review provides an opinion that drotrecogin alfa (activated) is a cost-efficient therapy that should be considered as part of a standard of care in healthcare systems that can provide a modern critical care service.