Severe sepsis--a new treatment with both anticoagulant and antiinflammatory properties

Checking linearity of non-parametric component in partially linear models with an application in systemic inflammatory response syndrome study

Two tests are proposed for checking the linearity of nonparametric function in partially linear models. The first one is based on a Crámer-von Mises statistic. This test can detect the local alternative converging to the null at the parametric rate 1/square root n. A bootstrap resample technique is provided to calculate the critical values. The second one is constructed in a penalized spline framework along with linear mixed-effects (LME) modeling. This is an extension likelihood ratio test for testing zero variance of random effects in LME models. Simulation experiments are conducted to explore the numerical performance of two tests. It is observed that two tests have good level properties, and the first test has a substantially superior power property over the second test in a variety of cases. A real data set is analysed with the proposed tests.

Secretory phospholipase A2 of group IIA: Is it an offensive or a defensive player during atherosclerosis and other inflammatory diseases?

Since its discovery in the serum of patients with severe inflammation and in rheumatoid arthritic fluids, the secretory phospholipase A2 of group IIA (sPLA2-IIA) has been chiefly considered as a proinflammatory enzyme, the result of which has been very intense interest in selective inhibitors of sPLA2-IIA in the hope of developing new and efficient therapies for inflammatory diseases. The recent discovery of the antibacterial properties of sPLA2-IIA, however, has raised the question of whether the upregulation of sPLA2-IIA during inflammation is to be considered uniformly negative and the hindrance of sPLA2-IIA in every instance beneficial. The aim of this review is for this reason, along with the results of various investigations which argue for the proinflammatory and proatherogenic effects of an upregulation of sPLA2-IIA, also to array data alongside which point to a protective function of sPLA2-IIA during inflammation. Thus, it could be shown that sPLA2-IIA, apart from the bactericidal effects, possesses also antithrombotic properties and indeed plays a possible role in the resolution of inflammation and the accelerated clearance of oxidatively modified lipoproteins during inflammation via the liver and adrenals. Based on these multipotent properties the knowledge of the function of sPLA2-IIA during inflammation is a fundamental prerequisite for the development and establishment of new therapeutic strategies to prevent and treat severe inflammatory diseases up to and including sepsis.

Effects of recombinant human activated protein C in human models of endotoxin administration

Alterations in the generation of activated protein C (APC) as well as in the interactions of APC with the endothelial protein C receptor are present in severe sepsis and acute lung injury. Administration of recombinant human activated protein C (rhAPC) improves the survival of critically ill patients with sepsis, but the mechanisms by which rhAPC produces benefit are not well defined. Human models of systemic and pulmonary endotoxin exposure may provide important insights into the mechanisms of action of rhAPC in critical illness. In volunteers given systemic endotoxin, rhAPC had minimal effects on physiologic parameters, including blood pressure, markers of inflammation, and measures of sepsis-induced coagulopathy. In contrast, in the setting of pulmonary endotoxin exposure, rhAPC decreased neutrophil migration into the airspaces and also diminished neutrophil chemotaxis. Administration of rhAPC did not affect other parameters of neutrophil function, including kinase activation, production of proinflammatory cytokines, or apoptosis. Such results indicate that the effects of rhAPC in inhibiting the infiltration of neutrophils into the lungs and other inflammatory sites may contribute to its beneficial effects in sepsis.

Editorial clubs as a new teaching tool in postgraduate training

BACKGROUND

We report an editorial club as a novel method of teaching systems-based competency in a hematology/oncology fellowship program.

METHOD

Editorial clubs focus on topics of broad economic, political, and legal ramifications of hematology/oncology and thereby help to develop systems competency as required by the Accreditation Council for Graduate Medical Education.

RESULTS

We began our program in 2001 and report on its functioning and outcome in a group of hematology/oncology fellows at the University of Arkansas for Medical Sciences.

CONCLUSION

Topics were diverse, fellows and faculty attendance was excellent, and fellows reported improved systems-based competency.

Challenges in the Therapeutic Use of a “So-Called” Universal Hemostatic Agent: Recombinant Factor VIIa

Recombinant factor VIIa (rFVIIa) was developed in the early 1990s to provide “bypassing” hemostatic therapy for hemophilia A and B patients with inhibitors. More recently, it has been licensed for use in patients with inherited deficiency of factor VII. Since it was licensed for use in hemophilia with inhibitors in the US, Europe, and other countries for these specific indications, it has been used selectively but in a wide array of clinical settings for uncontrolled hemorrhage in individuals without an inherited bleeding disorder. Many of these uses have been described in the medical literature as case reports or small, uncontrolled series. Several randomized clinical trials (RCT) for these “off-label” medical uses have been published in recent months and will serve as the focus of this review. In particular, a review of an RCT for spontaneous intracranial hemorrhage that has demonstrated clinical efficacy in reducing both mortality and volume of central nervous system hemorrhage will be offered. A brief discussion of hypothesized physiologic mechanisms of supraphysiologic doses of rFVIIa will introduce the clinical discussion of these broad off-label uses. Since rFVIIa is a very expensive therapy, possible strategies for optimizing its use in the these settings will be presented.

Challenge and Rechallenge: Drotrecogin alfa (activated)–Induced Prolongation of Activated Partial Thromboplastin Time in a Patient with Severe Sepsis

An 81-year-old woman with ischemic bowel underwent laparotomy with small-bowel resection and developed septic shock. She required broadspectrum antibiotics, norepinephrine, and mechanical ventilation. The patient received drotrecogin alfa (activated) 24 microg/kg/hour for a total of 67.5 hours. Coagulation parameters were monitored during her therapy. Significant increases in activated partial thromboplastin time (aPTT) during infusion led to two temporary discontinuations of the drug. Coagulation parameters decreased when the drug was held and increased with each rechallenge. The patient survived the episode and was discharged on postoperative day 27. Medical records of 26 other patients who received drotrecogin alfa (activated) at our institution from November 2001-August 2003 were reviewed retrospectively for coagulation parameters and bleeding rate. Of the 26 patients, nine (35%) were treatment compliant (>90% of the 96-hr course). Coagulopathy and bleeding resulted in early discontinuation in four (15%) and six (23%) patients, respectively. An increase in aPTT from baseline to during infusion of drotrecogin alfa (activated) was noted in 14 patients with complete data (p=0.56). A decrease in median platelet count from baseline to during infusion was noted in the six patients who bled during therapy (p=0.01). Two of these patients had platelet counts less than 30x10(3)/mm3 during administration. Drotrecogin alfa (activated) should be considered an anticoagulant. In postmarketing reports, clinically significant bleeding occurred more frequently than was noted in a large, randomized, multicenter trial. Patients receiving drotrecogin alfa (activated) should be closely monitored for prolongation of coagulation parameters. Temporary discontinuation of the drug should be considered when international normalized ratio is greater than 3.0, platelet count is less than 15x10(3)/mm3, and aPTT is greater than 100 seconds.

Drotrecogin alfa (recombinant human activated protein C) in severe acute pancreatitis

Introduction

Current concepts of the pathophysiology of acute pancreatitis suggest that disease progression from acinar injury to systemic illness involves a complex interplay between cellular and soluble inflammatory mediators and endothelial beds. To date, there is no specific pharmacologic intervention for acute pancreatitis. Death from acute pancreatitis remains a major issue, and late deaths are often related to haemorrhage and are associated with unresolved intra-abdominal sepsis. Drotrecogin alfa, an analogue of endogenous protein C, has antithrombotic, anti-inflammatory and profibrinolytic properties, and it has been shown to reduce mortality in clinical sepsis. Modulation of the coagulation cascade, although probably essential to the mode of action of drotrecogin alfa, can lead to an increased risk of bleeding.

Objective

The findings of the PROWESS trial have led to a more widespread use of drotrecogin alfa in sepsis and, critically, in sepsis-related conditions. The present article provides a concise summary of the interaction between the pathophysiology of acute pancreatitis and the modes of action of drotrecogin alfa, placing particular emphasis on the risks related to haemorrhage. Attention is further drawn to the reports of use of drotrecogin alfa in severe acute pancreatitis.

Conclusion

Synthesis of current knowledge on the modes of action and the side-effect profiles of drotrecogin alfa into a practical management algorithm must accept that evidence in this field is changing rapidly. At present there is insufficient evidence to justify the use of drotrecogin alfa in the early stages of this disease. In the later stages, when the probability of infection is proportionately greater, it is probable that intensive care clinicians will turn to drotrecogin alfa, in particular, in the setting of recent-onset organ dysfunction in established severe acute pancreatitis. Although this can be justified by extrapolation of the evidence from the PROWESS trial, practical critical care management in this setting must not overlook the need to rule out infection of necrosis, and must further be cognisant of the specific risks of haemorrhage in patients with prolonged pancreatitis and pancreatic necrosis.

Therapeutic intervention and targets for sepsis

Sepsis syndrome, a systemic response to infection, can beget devastating outcomes even in previously normal individuals. Recent research in septic patients has led to the discovery that early goal-directed resuscitation guided by continuous monitoring of mixed venous hemoglobin saturation, along with moderate doses of corticosteroids, can reduce mortality. An improved understanding of the complex interaction between the inflammatory and coagulant systems in sepsis pathophysiology has resulted in novel treatments, such as recombinant human activated protein C, which improves survival in patients with severe sepsis and a high risk of death. However, despite an increased understanding of the complex pathophysiology of this syndrome and the discovery of new, effective treatments, severe sepsis still results in significant morbidity and mortality. Consequently, investigations continue into additional therapeutic agents directed against novel targets. Following a review of recent advances in sepsis treatment, we briefly discuss a few of the new, promising therapeutic strategies currently being investigated.

Antithrombin ameliorates endotoxin-induced organ dysfunction more efficiently when combined with danaparoid sodium than with unfractionated heparin

OBJECTIVE

This study investigated the potential benefits of combination therapy using antithrombin (AT) with danaparoid sodium (DA) compared with the use of AT with unfractionated heparin (UFH) in the treatment of sepsis.

METHODS

Rats infused with lipopolysaccharide were treated with either DA alone, AT alone, AT plus DA, AT plus UFH, or human serum albumin as controls. AT (125 U/kg) was injected into the AT group immediately after lipopolysaccharide infusion. The AT/DA and AT/UFH groups received the same dose of AT in conjunction with either DA (400 U/kg) or UFH (400 U/kg). The status of the mesenteric microcirculation was examined by intra-vital microscopy and the laboratory indices of coagulation, inflammation, and organ dysfunction were measured.

RESULTS

The coagulation markers were improved following the administration of DA or UFH. The decreases in the WBC counts were significantly suppressed in the AT/DA group. The elevation of IL-6 decreased in the AT, DA, and AT/DA groups (all p<0.01) but not in the AT/UFH group. The prostaglandin I2 levels were significantly elevated only in the AT/DA group (p<0.05). The WBC adhesion was significantly suppressed in the DA, AT/UFH, and AT/DA groups (p<0.05), and the RBC velocity was best maintained in the AT/DA group with no associated increase in capillary hemorrhage. The elevation of ALT and BUN significantly improved only in the AT/DA group. ONCLUSION: Organ dysfunction can thus be alleviated by even moderate doses of AT replacement when co-administered with DA.

Simvastatin attenuates vascular leak and inflammation in murine inflammatory lung injury

Therapies to limit the life-threatening vascular leak observed in patients with acute lung injury (ALI) are currently lacking. We explored the effect of simvastatin, a 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitor that mediates endothelial cell barrier protection in vitro, in a murine inflammatory model of ALI. C57BL/6J mice were treated with simvastatin (5 or 20 mg/kg body wt via intraperitoneal injection) 24 h before and again concomitantly with intratracheally administered LPS (2 μg/g body wt). Inflammatory indexes [bronchoalveolar lavage (BAL) myeloperoxidase activity and total neutrophil counts assessed at 24 h with histological confirmation] were markedly increased after LPS alone but significantly reduced in mice that also received simvastatin (20 mg/kg; ∼35–60% reduction). Simvastatin also decreased BAL albumin (∼50% reduction) and Evans blue albumin dye extravasation into lung tissue (100%) consistent with barrier protection. Finally, the sustained nature of simvastatin-mediated lung protection was assessed by analysis of simvastatin-induced gene expression (Affymetrix platform). LPS-mediated lung gene expression was significantly modulated by simvastatin within a number of gene ontologies (e.g., inflammation and immune response, NF-κB regulation) and with respect to individual genes implicated in the development or severity of ALI (e.g., IL-6, Toll-like receptor 4). Together, these findings confirm significant protection by simvastatin on LPS-induced lung vascular leak and inflammation and implicate a potential role for statins in the management of ALI.

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.

Safety of drotrecogin alfa (activated) in the treatment of patients with severe sepsis

While severe sepsis continues to plague hospitals worldwide, new treatment modalities, including activated recombinant protein C (drotrecogin alfa, Xigris, Lilly), have become a standard treatment alternative in many institutional algorithms. Drotrecogin alfa was shown to have a beneficial effect on mortality versus placebo in the PROWESS (Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis) trial (p = 0.005), but its use is not completely without risk. An increased risk of bleeding, including severe bleeding episodes, exists ranging 3.5 - 5.2% in the drotrecogin alfa treatment group versus 2.0 - 5.0% in the placebo group. Patients at risk include those on concomitant heparin therapy (> 15,000 units/day), those with platelet counts <or= 30,000/mm(3), and those undergoing an invasive procedure during the scheduled infusion period. After almost three years on the US market, the reported incidence of severe bleeding episodes has risen only slightly from the pre-marketing era, at that time notable for restrictive treatment protocols, devoid of at-risk patients. Drotrecogin alfa, while a promising agent for severe sepsis, requires prudent patient evaluation for bleeding risks.

[Guidelines for the management of community pneumonia in adult who needs hospitalization]

Community acquired pneumonia is still an important health problem. In Spain the year incidence is 162 cases per 100,000 inhabitants with 53,000 hospital admission costing 115 millions of euros per year. In the last years there have been significant advances in the knowledge of: aetiology, diagnostic tools, treatment alternatives and antibiotic resistance. The Spanish Societies of Intensive and Critical Care (SEMICYUC), Infectious Diseases and Clinical Microbiology (SEIMC) and Pulmonology and Thoracic Surgery (SEPAR) have produced these evidence-based Guidelines for the management of community acquired pneumonia in Adults. The main objective is to help physicians to make decisions about this disease. The different points that have been developed are: aetiology, diagnosis, treatment and prevention.

Fetal and neonatal inflammatory response and adverse outcome

This article will define the concept of fetal/neonatal inflammatory response, and examine the complex interaction between inflammation and neurotoxicity. There appear to be important interactions between infection/inflammation and hypoxia-ischaemia leading to cytokine release and subsequent brain injury. This article will also define adverse outcome and summarize the complexities inherent to neurodevelopmental assessment. Finally, this article will investigate the currently available evidence suggesting a link between inflammatory response and adverse neurodevelopmental outcome, and focus on those variables that need further study: timing and nature of the infectious/inflammatory process; established and new anti-insult strategies; morbidity in organs other than the brain; genetic influences; and environmental factors.

Recombinant human activated protein C in sepsis: assessing its clinical use

Based on the results of the phase III PROWESS trial, recombinant human activated protein C (rhAPC) was approved by the Food and Drug Administration (FDA) for use in severely septic patients. Concerns regarding rhAPC's inconsistent effects, incomplete understanding of its mechanism of action, and its safety in particular subgroups were raised during the FDA's evaluation. This study attempts to assess the cost-effectiveness rhAPC by comparing its effects during recent clinical use to its prior phase III trial testing and by considering other potentially less expensive treatments with effects that may overlap those of rhAPC. In patients with similar numbers of injured organs, mortality rates may be higher with rhAPC during clinical use compared with the phase III trial. There may also be an increased risk of hemorrhage and other adverse events that necessitate early discontinuation of treatment. Many of the patients receiving rhAPC during clinical use may have otherwise been excluded from its phase III trial testing. Data from several recent phase III trials as well as a recent meta-analysis suggest that heparin and physiologic dose steroids offer substantially less expensive alternatives to rhAPC. Further phase IV testing will be required to confirm such possibilities.

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.

Heme oxygenase-1 messenger RNA expression is induced in peripheral blood mononuclear cells of pediatric cancer patients with systemic inflammatory response syndrome

OBJECTIVE

To determine whether heme oxygenase-1 messenger RNA expression in peripheral blood mononuclear cells is induced in pediatric cancer patients with the systemic inflammatory response syndrome (SIRS) and whether this expression correlates with the heme oxygenase-1 products, bilirubin and carboxyhemoglobin.

DESIGN

Prospective, controlled study.

SETTING

A tertiary care pediatric oncology hospital.

PATIENTS

Fourteen patients admitted to the intensive care unit with a diagnosis of SIRS by American College of Chest Physicians/Society for Critical Care Medicine consensus criteria and 17 control patients (off therapy, no acute illness).

INTERVENTIONS

Blood for bilirubin, carboxyhemoglobin, and heme oxygenase-1 messenger RNA expression was collected at study entry. SIRS patients continued to have samples collected every 12 hrs for 1 wk or until intensive care unit discharge. Heme oxygenase-1, bilirubin, and carboxyhemoglobin levels of SIRS patients were compared with controls, and correlation between heme oxygenase-1 and products was assessed.

MEASUREMENTS AND MAIN RESULTS

Within 48 hrs of study entry, maximum heme oxygenase-1 expression for all SIRS patients compared with controls was 5.5 +/- 1.0 vs. 1.1 +/- 0.1 (p < .0006). Maximum expression was > or =2.3-fold in 13 of 14 SIRS patients. Maximum heme oxygenase-1 expression also differed from minimum (5.5 +/- 1.0 vs. 1.6 +/- 0.3, p < .003). Maximum bilirubin and carboxyhemoglobin levels within 48 hrs of study entry differed between SIRS patients and controls (3.0 +/- 0.8 vs. 0.3 +/- 0.1, p = .006; and 1.2 +/- 0.2 vs. 0.6 +/- 0.1, p = .001, respectively). Bilirubin, but not carboxyhemoglobin, correlated with heme oxygenase-1 expression (p = .0013).

CONCLUSIONS

Heme oxygenase-1 messenger RNA, bilirubin, and carboxyhemoglobin levels were increased within 48 hrs of admission in pediatric cancer patients with SIRS. Heme oxygenase-1 expression correlated with serum bilirubin levels. The increase in heme oxygenase-1 expression may add to the understanding of the increase in serum bilirubin observed in patients with SIRS/sepsis. These findings support a role for heme oxygenase-1 in the physiologic response to inflammatory stress.

Tumor necrosis factor-alpha-induced TRPC1 expression amplifies store-operated Ca2+ influx and endothelial permeability

We determined the effects of TNF-alpha on the expression of transient receptor potential channel (TRPC) homologues in human vascular endothelial cells and the consequences of TRPC expression on the endothelial permeability response. We observed that TNF-alpha exposure increased TRPC1 expression without significantly altering expression of other TRPC isoforms in human pulmonary artery endothelial cells (HPAEC). Because TRPC1 belongs to the store-operated cation channel family, we measured the Ca(2+) store depletion-mediated Ca(2+) influx in response to thrombin exposure. We observed that thrombin-induced Ca(2+) influx in TNF-alpha-stimulated HPAEC was twofold greater than in control cells. To address the relationship between store-operated Ca(2+) influx and TRPC1 expression, we overexpressed TRPC1 by three- to fourfold in the human dermal microvascular endothelial cell line (HMEC) using the TRPC1 cDNA. Thrombin-induced store Ca(2+) depletion in these cells caused approximately twofold greater increase in Ca(2+) influx than in control cells. Furthermore, the inositol 1,4,5-trisphosphate-sensitive store-operated cationic current was increased greater than twofold in TRPC1-transfected cells compared with control. To address the role of Ca(2+) influx via TRPC1 in signaling endothelial permeability, we measured actin-stress fiber formation and transendothelial monolayer electrical resistance (TER) in the TRPC1 cDNA-transfected HMEC and TNF-alpha-challenged HPAEC. Both thrombin-induced actin-stress fiber formation and a decrease in TER were augmented in TRPC1-overexpressing HMEC compared with control cells. TNF-alpha-induced increased TRPC1 expression in HPAEC also resulted in marked endothelial barrier dysfunction in response to thrombin. These findings indicate the expression level of TRPC1 in endothelial cells is a critical determinant of Ca(2+) influx and signaling of the increase in endothelial permeability.

Advances in sepsis treatment

Investigations of novel sepsis treatments have proven ineffective in the past. Despite advances in overall care of critically ill patients, therapies specifically designated for sepsis were lacking. However, research unveiled a complex interaction between the coagulation and inflammation systems, which has served as an impetus for innovative pharmacologic therapies in the treatment of patients with sepsis. This article summarizes the results of trials involving drotrecogin alfa (activated), or recombinant human activated protein C, the only medicine currently approved by the US Food and Drug Administration for the treatment of severe sepsis. In addition, the beneficial effects of early, goal-directed resuscitation, guided by continuous central venous oxygen saturations, are discussed, with the issues involved in the use of corticosteroids in a subset of patients with septic shock. This article also reviews the beneficial effects of tight glycemic control in postoperative critically ill patients and considers whether the data can be extrapolated to medical patients.

Disorders of hemostasis during the surgical management of severe necrotizing pancreatitis

OBJECTIVES

Several clinical studies of severe necrotizing pancreatitis (SNP) suggest profound activation of coagulation as well as activation of the fibrinolytic system. The aim of this study was to evaluate the hemostatic derangements in patients who were managed for SNP.

METHODS

Forty-one operated-on patients with SNP were analyzed regarding clinical outcome and activation of the coagulation systems. Serial measurement of coagulation, anticoagulation, and fibrinolysis parameters: prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen, antithrombin III (AT III), protein C, plasminogen activator inhibitor-1 (PAI-1), d-dimer, alpha2-antiplasmin, and plasminogen were performed on days 1, 3, 5, 7, 10, and 14 after the initial operation. According to treatment outcome at the end of study, groups of 26 survivors and 15 nonsurvivors were compared.

RESULTS

Nonsurvivors had significantly lower levels of activity of protein C and AT III, and higher concentrations of d-dimer and PAI-1 than survivors. The other measured parameters did not show significant differences between the compared groups of patients.

CONCLUSIONS

Changes in protein C, AT III, d-dimer and PAI-1 levels indicate exhaustion of fibrinolysis and coagulation inhibitors in patients with poor outcome during the course of SNP.

Effect of drotrecogin alfa (activated) on human endothelial cell permeability and Rho kinase signaling

OBJECTIVE

To explore whether the improvement in organ function and the vasoactive effect observed in the clinical studies of drotrecogin alfa (activated) (recombinant human activated protein C, rhAPC) in sepsis are a result of rhAPC's effect on endothelial cell (EC) permeability and modulation of the intracellular cytoskeleton via the Rho kinase signaling pathway.

DESIGN

Findings regarding dose and duration of exposure to the drug with sequential addition of rhAPC and mediators (thrombin, histamine, interleukin-1 beta).

SETTING

Research laboratory in a pharmaceutical company.

SUBJECTS

Cultured primary human EC from different tissues and vascular beds.

INTERVENTIONS

A monolayer of EC was incubated with either rhAPC, thrombin, histamine, or interleukin-1 beta alone or with rhAPC in combination with thrombin or interleukin-beta. The effect of rhAPC and mediators on EC permeability was monitored with measurement of electrical resistance. The effect on Rho kinase pathway signaling was monitored by the levels of phosphorylated myosin light chain and blockage with the Rho kinase specific inhibitor, Y27632.

MEASUREMENTS AND MAIN RESULTS

Thrombin alone induced an early, concentration-dependent, and transient leakiness of EC. Interleukin-1 beta (0.5 ng/mL) induced an early, irreversible leakiness of EC. rhAPC (0.05-0.2 microg/mL, approximate median therapeutic blood levels) alone had no effect on EC permeability. rhAPC at > or=1 microg/mL induced an early EC leakage. rhAPC (0.19 microg/mL) attenuated the leakage induced by 0.5 ng/mL interleukin-1beta on microvascular EC derived from lung and skin and partially attenuated the leakage induced by 0.25 nM thrombin on human coronary arterial ECs. Levels of phosphorylated myosin light chain increased rapidly in human coronary arterial ECs when stimulated with thrombin or rhAPC (about 100-fold less potent) in a concentration-dependent manner via the Rho kinase signaling pathway. Short (5 mins) preconditioning of human coronary arterial ECs with 0.19 microg/mL rhAPC partially blocked the increase in phosphorylated myosin light chain levels induced by thrombin (0.06-0.2 nM).

CONCLUSIONS

At concentrations exceeding physiologic and therapeutic levels, rhAPC increases EC permeability, an effect not seen at lower concentrations. The data suggest that interpretation of published in vitro and in vivo data of rhAPC and EC permeability should take into consideration the concentrations of rhAPC used or achieved. Other preliminary novel observations suggest that studying the effects of rhAPC on EC permeability and intracellular cytoskeletal organization may provide understanding of the effect of rhAPC on EC function.

Postoperative care of vascular surgery patients

Vascular surgery continues to carry one of the highest postoperative morbidity and mortality rates. A detailed understanding of postoperative central nervous, myocardial, respiratory, and renal pathophysiology potentially helps to improve outcome. Current economic constraints, combined with changing intraoperative management, prompt inquiry into whether these patients can safely be managed outside of an intensive care unit setting. This article reviews whether efforts to less invasively manage these patients intraoperatively improves postoperative outcome remains under investigation, and what is known about the effects on postoperative outcome of regional anesthesia for carotid endarterectomy and endovascular treatment of aortic vascular disease.

The puzzle of sepsis: fitting the pieces of the inflammatory response with treatment

Sepsis is a complex syndrome characterized by simultaneous activation of inflammation and coagulation in response to microbial insult. These events manifest as systemic inflammatory response syndrome (SIRS)/sepsis symptoms through release of proinflammatory cytokines, procoagulants, and adhesion molecules from immune cells and/or damaged endothelium.Conventional treatments have focused on source control, antimicrobials, vasopressors, and fluid resuscitation; however, a new treatment paradigm exists: that of treating the host response to infection with adjunct therapies including early goal directed therapy, drotrecogin alfa (activated), and immunonutrition. The multimechanistic drotrecogin alfa (activated) has been shown to reduce mortality in the severely septic patient when combined with traditional treatment. Therapies targeting improved oxygen and blood flow and reduction of apoptosis and free radicals are under investigation. Early sepsis diagnosis through detection of pro calcitonin, C reactive protein, sublingual CO2, and genetic factors may be beneficial. Ultimately, intervention timing may be the most important factor in reducing severe sepsis mortality.

Cost-effectiveness of recombinant human activated protein C and the influence of severity of illness in the treatment of patients with severe sepsis

PURPOSE

To evaluate the cost-effectiveness of recombinant human activated protein C (rhAPC) compared with usual therapy for patients with severe sepsis, and also to determine the influence that severity of illness exerts on cost-effectiveness.

MATERIALS AND METHODS

We use a Markov model-based cost-effectiveness analysis of treatment strategies for patients with severe sepsis. Therapy includes treatment with either rhAPC and usual therapy, or usual therapy alone. Probabilities for clinical outcomes were obtained from a large randomized clinical trial comparing the use of rhAPC with placebo (PROWESS study) and from outcomes literature for patients with severe sepsis and its complications. Cost estimates were based on Medicare reimbursement rates, Health Care Financing Administration information and the literature. Outcome measures include life-years, quality-adjusted life-years (QALYs), costs, and incremental cost-effectiveness.

RESULTS

Compared with usual therapy alone, rhAPC treatment for patients with very severe sepsis (APACHE II score > or = 25) was associated with an incremental cost-effectiveness ratio of $13 493/QALY. Treatment of patients with less severe sepsis with rhAPC (APACHE II score < 25) had an incremental cost-effectiveness ratio of $403,000/QALY. For patients with very severe sepsis the incremental cost-effectiveness ratio for treatment with rhAPC remained under $30,000/QALY, over a broad range of variables, including costs of rhAPC, costs of acute care and costs and probabilities of complications of treatment. For patients with less severe sepsis, drug costs would need to fall well below current market price before achieving cost-effectiveness. A probabilistic sensitivity analysis comparing rhAPC treatment with usual therapy for patients with very severe sepsis showed that < 1% of Monte Carlo simulations had incremental cost-effectiveness ratios > $50,000/QALY.

CONCLUSIONS

The use of rhAPC for the treatment of patients with very severe sepsis, as determined by APACHE II score > or = 25, appears cost-effective, while treatment of patients with APACHE II score < 25 is not cost-effective.

The evaluation and management of shock

Shock is an emergency that requires continuous bedside evaluation, resuscitation, and re-evaluation. The initial bedside examination allows the clinician to determine whether the patient exhibits a clinical picture that is consistent with hypovolemic, cardiogenic, or vasodilatory shock. The primary survey dictates urgent initial resuscitation that usually consists of intubation, ventilation, and volume support. Vasoactive therapy is started when the patient is well volume-resuscitated and consists of inotropic support for cardiogenic shock and pressor therapy for vasodilatory shock. The secondary survey is helpful in revealing the cause of shock and necessary to institute early definitive therapy. Early shock has a hemodynamic component, which is often easily reversed. Septic shock and prolonged shock from any cause has an inflammatory component, which is not easily reversed and leads to multiple-system organ failure (MSOF) and death. Success in treatment of shock depends on early recognition of shock and the rapid tempo of resuscitation of its hemodynamic component to prevent or minimize the inflammatory component.

Critical care infectious disease

Septic shock, toxic shock syndrome, acute respiratory distress syndrome, and catheter-related infections are conditions in which intensive care management of the patient may be necessary. Toxic shock syndrome is a toxin-mediated illness that is not limited to young menstruating women and should be considered in women and men who present with fever, hypotension, rash, and multiorgan dysfunction. Sepsis is the leading cause of death in critically ill patients in the United States and is the most common predisposing factor for acute lung injury or acute respiratory distress syndrome. Central venous catheters are often a necessity for optimal patient care in these critically ill patients.

Role of Corticosteroids in Septic Shock

OBJECTIVE

To highlight the role of relative adrenal insufficiency in the outcome of critically ill patients with sepsis and systematically review the literature regarding the use of corticosteroids for management of severe sepsis/septic shock.

DATA SOURCES

A computerized search of MEDLINE, EMBASE, and the Cochrane Database was undertaken from 1966 to March 2003 using the search terms intensive care unit, critical care, corticosteroids, glucocorticoids, adrenal insufficiency, sepsis, and septic shock. Bibliographies of all articles retrieved were searched for relevant articles not identified by the computerized search.

DATA EXTRACTION/SYNTHESIS

Six trials were identified after publication of the meta-analyses (1995), with a total of 505 patients. The results of these trials in septic shock suggest that low-dose corticosteroids can reduce vasopressor requirements and hasten reversal of shock. Some of these trials suggested a possible mortality benefit from therapy, and no trial demonstrated an increase in mortality or significant adverse effects. The benefit of this therapy may depend on the presence of relative adrenal insufficiency, as identified by the adrenocorticotropic hormone stimulation test.

CONCLUSIONS

Low-dose corticosteroids should be administered to patients with septic shock empirically, but should be discontinued if relative adrenal insufficiency is not confirmed.

Hematologic abnormalities in severe neonatal necrotizing enterocolitis: 25 years later

Necrotizing enterocolitis (NEC), the most common surgical emergency in newborns, remains a therapeutic challenge for clinicians. The hematological manifestations associated with NEC were first described 25 years ago. This review discusses current knowledge of the pathophysiology involved in disturbances in megakaryocytopoiesis, coagulation, leukopoiesis, and erythropoiesis that accompany the clinical entity NEC. The discussion includes current understanding of and potential strategies for treating the hematopoietic disturbances that occur secondary to NEC.

Relationship between the inflammation and coagulation pathways in patients with severe sepsis: implications for therapy with activated protein C

In patients with severe sepsis, thrombin has been implicated in the interrelationship between the coagulation and inflammation pathways. Thrombin is responsible for conversion of fibrinogen to fibrin (thrombus formation). Thrombin also activates endothelial cells, white blood cells and platelets. Regulation of both the coagulation and inflammation pathways is in part through the interaction of thrombin and activated protein C. Activated protein C has particular attributes that may inhibit microvascular thrombi, promote fibrinolysis and directly dampen the pro-inflammatory aspect of infection. In patients with severe sepsis, many investigators have demonstrated an active coagulopathic state, with low protein C levels. A phase III clinical trial has now demonstrated reduced mortality in patients with severe sepsis receiving activated protein C.

Inter-alpha inhibitor proteins in infants and decreased levels in neonatal sepsis

OBJECTIVE

Adjunctive tests are needed to predict sepsis in the newborn and to lower the rate or duration of unnecessary antibiotic use. We evaluated the normal Inter-alpha inhibitor protein (IaIp) values in infants and the association of plasma levels of IaIp with sepsis in term and preterm newborns.

METHODS

Plasma IaIp levels were measured by enzyme-linked immunosorbent assay in samples from 135 newborn infants at a wide range of gestational ages (24-42 weeks). IaIp levels were also determined in 19 infants undergoing prospective evaluation for sepsis.

RESULTS

IaIp levels in umbilical cord blood and circulating peripheral blood of healthy newborn infants (525+/-66 mg/L) were not significantly different from the level in healthy adults (691+/-80 mg/L). IaIp levels were similar in infants between 24 and 42 weeks gestational age. There was a significant reduction in IaIp levels in infants with sepsis compared with nonseptic controls (169+/-126 mg/L vs 613+/-286 mg/L, P<.0001).

CONCLUSIONS

IaIp levels in the blood of newborns are independent of gestational age and similar to adults. IaIp levels are significantly reduced in infants with bacterial sepsis and might serve as an adjunctive diagnostic marker to allow prospective reduction of antibiotic use.

The immunopathogenesis of meningococcal disease

This review describes the mechanisms of the immune response to meningococcal disease, examining the extent to which individual variation of the immune response can determine susceptibility. It concludes by summarising the difficulties encountered by recent efforts to develop new immunomodulatory treatments.

Treating severe sepsis with drotrecogin alfa (activated)

Severe sepsis is a complex condition with mortality rates ranging from 30 to 50% in spite of advances in critical care. Xigris (drotrecogin alfa (activated)) is associated with an absolute reduction in the risk of death of 6.1% and was granted European Union marketing authorization in August 2002.

Bacteremic sepsis in intensive care: temporal trends in incidence, organ dysfunction, and prognosis

OBJECTIVE

To determine whether changes have occurred at our center in the incidence, patterns of organ dysfunctions, prognostic factors, and case-fatality rate of bacteremic sepsis.

DESIGN

Retrospective comparative study (1984-1988 vs. 1994-1997).

SETTING

University hospital surgical intensive care unit.

PATIENTS

A total of 372 critically ill patients with sepsis and positive blood cultures.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

In the 1984-1988 study, 176 patients developed bacteremic sepsis (3.2 per 100 admissions), with a fatality rate of 35% at 28 days, whereas in the 1994-1997 study, 196 patients had bacteremic sepsis (4.3 per 100 admissions), with a 28-day fatality rate of 37%. The frequency of primary bacteremia increased from 21% to 47% (p <.001), paralleled by an increase in the proportional frequency of Gram-positive microorganisms. In 1984-1988, 69% (n = 120) of patients had at least one organ dysfunction, compared with 80% (n = 156) in 1994-1997 (p =.02). The prevalence of pulmonary and cardiac dysfunction increased. The case- fatality rate of septic shock remained high (69% vs. 68%). For both cohorts, the two strongest predictors of mortality remained the Acute Physiology and Chronic Health Evaluation II score at the onset of sepsis and the number of evolving organ dysfunctions.

CONCLUSION

The fatality rate of bacteremic sepsis remained constant over the study period, despite an increased incidence of bacteremia and associated organ dysfunction. Continued efforts need to be directed toward the prevention of bacteremic sepsis, given the magnitude and poor prognosis of this syndrome.

Drotrecogin alfa (recombinant human activated protein C) for the treatment of severe sepsis

BACKGROUND

The search for a life-preserving drug to treat sepsis has increased understanding of the pathogenesis of the process but produced little in the way of successful treatments. The prospective, randomized, double-blind, placebo-controlled, Phase III, multicenter Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) trial suggested that drotrecogin alfa--recombinant human activated protein C--significantly improved 28-day mortality rates in acute sepsis (P = 0.005).

OBJECTIVES

The goals of this drug review were to summarize the recent findings regarding the pathogenesis of sepsis and septic shock, as well as the results of select immunomodulator drug trials, and to offer a comprehensive review of the mechanism of action, pharmacokinetic profile, efficacy and safety profile, and pharmacoeconomics of drotrecogin alfa.

METHODS

The English-language literature was searched using the EMBASE and MEDLINE databases. In EMBASE, the subject headings drotrecogin, activated protein C, and sepsis were used to search publications from 1980 through September 2002. In MEDLINE, the MeSH heading protein C and subject heading sepsis were used to search publications from 1966 through September 2002. Published abstracts of recent meetings and proceedings of the US Food and Drug Administration were also reviewed.

RESULTS

Drotrecogin alfa mimics the endogenous protein depleted during acute sepsis. Its activity as an antithrombotic, anti-inflammatory, and profibrinolytic agent appears to diminish the negative outcomes of acute sepsis, notably mortality at 28 days. The results of the PROWESS trial support this finding. A bleeding risk was noted during Phase II and III trials despite efforts to exclude those patients at high risk of bleeding.

CONCLUSIONS

Drotrecogin alfa is the first adjunctive agent for the treatment of sepsis to display clinically and statistically significant effects on mortality rates at 28 days. Many questions remain regarding which patients are ideal candidates for treatment. New research and treatment guidelines are necessary to address these questions.