Anti-inflammatory therapies to treat sepsis and septic shock: a reassessment

Early effects of lipopolysaccharide on cytokine release, hemodynamic and renal function in newborn piglets

BACKGROUND

Gram-negative sepsis in newborns is associated with high mortality and morbidity. Lipopolysaccharide (LPS) and cytokines released upon exposure to gram-negative sepsis are well known to be involved in the pathophysiology.

OBJECTIVE

In this report we investigate cytokine release, hemodynamic, and renal function induced by LPS in a newborn animal model with the intention to further examine early changes in gram-negative sepsis.

METHODS

Five 7- to 10-day-old domestic piglets were anesthetized and catheters placed in the jugular veins, left ventricle, and femoral artery. Urine output was monitored via suprapubic cystostomy. Mean arterial pressure, heart rate, and arterial blood gases were continuously monitored. Thirty minutes after line placement and obtaining baseline values, 0.06 mug/kg LPS were administered intravenously. One, 2, and 3 h later samples were taken to monitor tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, endothelin, and nitric oxide (NO)/nitrate via ELISA. In addition, blood flow was assessed by the microsphere method.

RESULTS

Our data show an initial surge of TNF-alpha and IL-1beta at 1 h after exposure to LPS. NO/nitrate, endothelin, and hemodynamic as well as metabolic changes became apparent mostly 3 h after exposure, by which time TNF-alpha and IL-1beta fell back to baseline.

CONCLUSIONS

Our sepsis model suggests a brief initial TNF-alpha and IL-1beta surge following LPS challenge; however, their effects become apparent by the time the levels are already subsiding. The emergence of vasoactive substances, NO and endothelin, precedes the first substantial clinical symptoms.

Ulinastatin alone does not reduce caspase 3-mediated apoptosis in protease-positive Aeromonas hydrophilia-induced sepsis

BACKGROUND/PURPOSE

To evaluate the effect of ulinastatin, a protease inhibitor, on survival and apoptosis in protease-positive Aeromonas hydrophilia (PPAH)-induced sepsis.

METHODS

Thirty mice were randomly allocated to receive intraperitoneal injection of either phosphate buffered saline (PBS) (control mice, n = 10) or PPAH (PPAH mice, n = 20). After 30 minutes, control mice received an additional intraperitoneal PBS injection, 10 PPAH mice received intraperitoneal PBS injection (non-treated PPAH mice), and the remaining 10 PPAH mice received an intraperitoneal injection of ulinastatin (ulinastatin-treated PPAH mice).

RESULTS

Survival at 24 hours was 100% in control mice, and 35% (p < 0.05) in PPAH mice; the survival rate in non-treated and ulinastatin-treated PPAH mice were 30% and 40% (p > 0.05), respectively. The thymus weight (mg) decreased significantly in PPAH mice (51.1 +/- 14.9) compared to control mice (69.7 +/- 14.4; p < 0.001); there was no difference between ulinastatin-treated (52 +/- 13.9; p > 0.05) and non-treated PPAH mice (50.4 +/- 16). The thymus gland cell count reduced significantly in PPAH mice (8.1 +/- 4.7 x 10(7)) compared to control mice (12.8 +/- 6.6 x 10(7); p < 0.01), and immunofluorescence analysis demonstrated that the reduced cells were mostly CD4+ CD8+, in contrast to the increase in CD4+ CD8- cells. There was no difference in cell count between ulinastatin-treated (8.7 +/- 4.9 x 10(7)) and non-treated PPAH mice (7.4 +/- 4.6 x 10(7); p > 0.05). Caspase 3-mediated apoptosis was not detectable in control mice in contrast to the pronounced manifestation in PPAH mice.

CONCLUSION

PPAH-induced sepsis has a high mortality that is related to lymphocyte apoptosis. Ulinastatin alone does not significantly reduce caspase 3-mediated lymphocyte apoptosis.

Inhibition of inducible nitric oxide synthase attenuates acute endotoxin-induced lung injury in rats

1. In the present study, we investigated the effects of the inducible nitric oxide (iNOS) inhibitors S-methylisothiourea (SMT) and l-N(6)-(1-iminoethyl)-lysine (l-Nil) on endotoxin-induced acute lung injury (ALI), as well as the associated physiological, biomedical and pathological changes, in anaesthetized Sprague-Dawley rats and in rat isolated perfused lungs. 2. Endotoxaemia was induced by an intravenous (i.v.) infusion of lipopolysaccharide (LPS; Escherichia coli 10 mg/kg). Lipopolysaccharide produced systemic hypotension and tachycardia. It also increased the lung weight/bodyweight ratio, lung weight gain, exhaled nitric oxide (NO), the protein concentration in bronchoalveolar lavage and microvascular permeability. 3. Following infusion of LPS, plasma nitrate/nitrite, methyl guanidine, pro-inflammatory cytokines (tumour necrosis factor-alpha and interleukin-1beta) were markedly elevated. Pathological examination revealed severe pulmonary oedema and inflammatory cell infiltration. Pretreatment with SMT (3 mg/kg, i.v.) or l-Nil (3 mg/kg, i.v.) significantly attenuated the LPS-induced changes and ALI. 4. The results suggest that the inflammatory responses and ALI following infusion of LPS are due to the production of NO, free radicals and pro-inflammatory cytokines through the iNOS system. Inhibition of iNOS is effective in mitigating the endotoxaemic changes and lung pathology. Inhibitors of iNOS may be potential therapeutic agents for clinical application in patients with acute respiratory distress syndrome.

Therapeutic effects of TAK-242, a novel selective Toll-like receptor 4 signal transduction inhibitor, in mouse endotoxin shock model

Ethyl (6R)-6-[N-(2-chloro-4-fluorophenyl)sulfamoyl]cyclohex-1-ene-1-carboxylate (TAK-242), a novel small molecule that selectively inhibits Toll-like receptor 4-mediated signaling, inhibits various kinds of inflammatory mediators such as nitric oxide (NO), tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, IL-6, IL-10, macrophage inhibitory protein (MIP)-2 and prostaglandin E2 from lipopolysaccharide (LPS)-stimulated macrophages. The effects of TAK-242 were evaluated in a mouse model of endotoxin shock. Intravenous administration of TAK-242 to mice 1 h before LPS challenge dose-dependently inhibited LPS-induced increases in serum levels of TNF-alpha, IL-1beta, IL-6, IL-10, MIP-2, and NO metabolites. TAK-242 protected mice from LPS-induced lethality in a similar dose-dependent manner, and rescued 100% of mice at a dose of 1 mg/kg. Interestingly, TAK-242 worked quickly, and showed beneficial effects even when administered after LPS challenge. Even though increases in serum levels of IL-6 and hypothermia were already evident 2 h after LPS challenge, TAK-242 administration inhibited further increase in IL-6 levels and decrease in body temperature. LPS-induced increases in serum levels of organ dysfunction markers, such as alanine aminotransferase, total bilirubin, and blood urea nitrogen, were also significantly suppressed by post-treatment as well as pre-treatment. Furthermore, administration of 3 mg/kg TAK-242 significantly increased survival of mice, even when given 4 h after LPS challenge. These results suggest that TAK-242 protects mice against LPS-induced lethality by inhibiting production of multiple cytokines and NO. TAK-242 has a quick onset of action and provides significant benefits by post-treatment, suggesting that it may be a promising drug candidate for the treatment of sepsis.

New evaluation therapies for sepsis

This article presents an analysis of the literature of the last 2 years on the treatment of sepsis and septic shock. It appears that most of the antimediator therapies applied in phase II or III clinical trials yielded disappointing results. But, many other therapeutic approaches are proposed or are ongoing, and many papers report critical analysis of the reasons for the lack of success of past clinical trials.

Clinical trials in sepsis: an update

In this article, we place clinical sepsis trials from the past year in the context of similar sepsis trials run over the past three decades. These recent clinical sepsis trials include studies of agents administered to limit the effects of specific host proinflammatory mediators (tumor necrosis factor, platelet-activating factor and prostaglandins), studies of use of corticosteroids at low doses late in sepsis, and studies of administration of high doses of a nonspecific nitric oxide synthase inhibitor to decrease nitric oxide production in septic shock. The three trials of agents designed to limit host proinflammatory mediators showed minimal beneficial effects, results that are similar to those of the approximately 20 previous trials of similar agents. Low-dose corticosteroid therapy reversed shock and showed nonsignificant trends towards improvements in survival rates. In contrast, high doses of corticosteroids given early in sepsis have shown harmful effects in clinical sepsis trials. Finally, inhibition of nitric oxide production was lethal, indicating that high doses of nonspecific inhibitors of nitric oxide production are contraindicated in septic shock.

Exercise training attenuates septic responses in conscious rats

PURPOSE

To evaluate the effects of exercise training on the changes induced by endotoxin in arterial pressure, heart rate (HR), blood cells, biochemical factors, plasma nitrite/nitrate, methyl guanidine (MG), proinflammatory cytokines, and pathology of the heart, liver, and lung.

METHODS

Twenty-four 10-wk-old male Wistar-Kyoto rats weighing 320-350 g were randomly assigned into two groups. The exercise-trained group (Tr; N = 12) received exercise training for 4 wk. The control (Con) group was placed on the treadmill and remained sedentary for the same time period. Endotoxemia was induced by intravenous (i.v.) infusion of lipopolysaccharide (LPS; 10 mg.kg(-1)) for 20 min, after which the animals were observed for 72 h. The femoral artery was cannulated to monitor arterial pressure and HR. Blood samples were collected 1 h before and at various times after LPS infusion. We determined plasma nitrite/nitrate, MG, white blood cells, neutrophils, lymphocytes, red blood cells, blood urea nitrogen, creatinine (Cr), aspartate aminotransferase, alanine aminotransferase, lactic acid dehydrogenase, creatine phosphokinase, amylase, lipase, tumor necrosis factor(alpha), and interleukin-1(beta). The heart, liver, and lung were taken for pathological examination and assessment after the experiment.

RESULTS

The Tr group had lower basal levels of arterial pressure, HR, MG, neutrophils, and Cr than the Con group. Exercise training attenuated the LPS-induced decreases in blood cells. After LPS administration, plasma levels of nitrate/nitrite, MG, biochemical factors, and proinflammatory cytokines in the Con group were higher than in the Tr group. Pathological examination and assessment revealed that cardiac, hepatic, and pulmonary injury were more severe in the Con group than in the Tr group.

CONCLUSIONS

Exercise training attenuates septic responses and protects organs from damage in sepsis.

Bound to shock: protection from lethal endotoxemic shock by a novel, nontoxic, alkylpolyamine lipopolysaccharide sequestrant

Lipopolysaccharide (LPS), or endotoxin, a structural component of gram-negative bacterial outer membranes, plays a key role in the pathogenesis of septic shock, a syndrome of severe systemic inflammation which leads to multiple-system organ failure. Despite advances in antimicrobial chemotherapy, sepsis continues to be the commonest cause of death in the critically ill patient. This is attributable to the lack of therapeutic options that aim at limiting the exposure to the toxin and the prevention of subsequent downstream inflammatory processes. Polymyxin B (PMB), a peptide antibiotic, is a prototype small molecule that binds and neutralizes LPS toxicity. However, the antibiotic is too toxic for systemic use as an LPS sequestrant. Based on a nuclear magnetic resonance-derived model of polymyxin B-LPS complex, we had earlier identified the pharmacophore necessary for optimal recognition and neutralization of the toxin. Iterative cycles of pharmacophore-based ligand design and evaluation have yielded a synthetically easily accessible N(1),mono-alkyl-mono-homologated spermine derivative, DS-96. We have found that DS-96 binds LPS and neutralizes its toxicity with a potency indistinguishable from that of PMB in a wide range of in vitro assays, affords complete protection in a murine model of LPS-induced lethality, and is apparently nontoxic in vertebrate animal models.

Treatment of severe sepsis: where next? Current and future treatment approaches after the introduction of drotrecogin alfa

Severely septic patients continue to experience excessive morbidity and mortality despite recent advances in critical care. Although significant resources have been invested in new treatments, almost all have failed to improve outcomes. An improved understanding of sepsis pathophysiology, including the complex interactions between inflammatory, coagulation, and fibrinolytic systems, has accelerated the development of novel treatments. Recombinant human activated protein C (rhAPC), or drotrecogin alfa (activated) (DAA), is currently the only US Food and Drug Administration (FDA)-approved medicine for the treatment of severe sepsis, and only in patients with a high risk of death. This review will discuss the treatment of severe sepsis, focusing on recent discoveries and unresolved questions about DAA's optimal use. Increasing pharmacological experience has generated enthusiasm for investigating medicines already approved for other indications as treatments for severe sepsis. Replacement doses of hydrocortisone and vasopressin may reduce mortality and improve hypotension, respectively, in a subgroup of patients with catecholamine-refractory septic shock. In addition to discussing these new indications, this review will detail the provocative preliminary data from four promising treatments, including two novel modalities: antagonizing high mobility group box protein and inhibiting tissue factor (TF). Observational data from the uncontrolled administration of heparin or statins in septic patients will also be reviewed.

Anti-cytokine and anti-inflammatory therapies for the treatment of severe sepsis: progress and pitfalls

The medical care of patients with sepsis or severe inflammatory response syndromes has seen tremendous technological advancements in recent years; yet, several clinical studies with anti-cytokine therapies targetted to this population have met with disappointing results. Four primary factors have been identified that represent potential pitfalls involving the use of biological response modifiers in critically-ill patients. First, the physiological response in the stressed patient is complex. Redundancy within this system may not allow a single intervention to produce a clinical response. Second, the critically-ill patient population is heterogenous and important factors including the age of the patient, associated co-morbidities, the nature of the original injury and the presence or absence of an ongoing injury can modulate the effectiveness of a specific therapy. Third, the timing of the therapeutic intervention can be difficult to standardize among patients and can often produce differing results. A greater understanding of the physiological response to injury has shown that there are both proinflammatory and anti-inflammatory processes ongoing simultaneously. Determining the optimal time to intervene within this framework can be problematic. Fourth, the presence of genetic polymorphisms within the general population has identified subsets of individuals who may have different physiological responses to similar stresses. The relative proportions of patients with these polymorphisms within clinical trials may affect outcome and data analysis. Thus, a better understanding of these issues will result in improvement of the experimental design of clinical trials involving anti-cytokine therapies and critically-ill patients. Avoidance of these pitfalls will enhance the quality and utility of outcomes research in this subset of patients.

Treatment of sepsis: current status of clinical immunotherapy

While antibiotics address the root cause of sepsis--that of pathogen infection--they fail to provide an adequate cure for the condition. Currently, 30% to 50% of septic patients die, and this figure is likely to increase in line with the proliferation of multi-drug resistant bacteria. With an increased understanding of the immune response, it has been proposed that modulation of this defence mechanism offers the best hope of cure. Many entry-points in the immune system have been identified and targeted therapies have been developed,but why are these not in routine clinical practice? This review examines the latest evidence for the use of immuno-modulating drugs, obtained from human clinical trials. We discuss cytokine-based therapies, steroids and anti-coagulants. Finally, consideration is given as to why successful therapies in the laboratory, and in vivo models, do not automatically translate into clinical benefit

The role of initial trauma in the host's response to injury and hemorrhage: insights from a correlation of mathematical simulations and hepatic transcriptomic analysis

Trauma and hemorrhagic shock (HS) elicit severe physiological disturbances that predispose the victims to subsequent organ dysfunction and death. The general lack of effective therapeutic options for these patients is mainly due to the complex interplay of interacting inflammatory and physiological elements working at multiple levels. Systems biology has emerged as a new paradigm that allows the study of large portions of physiological networks simultaneously. Seeking a better understanding of the interplay among known inflammatory pathways, we constructed a mathematical model encompassing the dynamics of the acute inflammatory response that incorporates the intertwined effects of inflammation and global tissue damage. The model was calibrated using data from C57Bl/6 mice subjected to endotoxemia, sham operation (i.e., surgical trauma induced by cannulation [ST]) or ST + HS+ resuscitation (ST-HS-R). An in silico simulation, made at whole-organism level, suggested that similar pathways of different magnitudes were operant as the degree of total body damage increased. We sought to validate this hypothesis by subjecting mice to HS and comparing the models predictions to circulating markers of inflammation and tissue injury as well as the global transcriptomic response of the liver. C57Bl/6 mice were subjected to ST or ST-HS (without resuscitation). Liver gene expression was assessed using an Affymetrix DNA microarray (GeneChip Mouse Expression Set 430A, Affymetrix, Santa Clara, CA), which contains 22,621 probe sets and effectively interrogates 12,341 mouse genes. The microarray data sets were subjected to hierarchical clustering and pathway analysis. In agreement with model predictions, circulating levels of inflammation/tissue injury markers and the microarray analysis both demonstrated that ST alone accounts for a substantial proportion of the observed phenotypic and genetic/molecular changes versus untreated animals. The addition of HS further increased the magnitude of gene expression, but relatively few additional genes were recruited. Mathematical simulations and DNA microarrays, both systems biology tools, may provide valuable insight into the complex global physiological interactions that occur in response to trauma and hemorrhagic shock.

Hemodynamic goals in randomized clinical trials in patients with sepsis: a systematic review of the literature

INTRODUCTION

Patients with sepsis suffer high morbidity and mortality. We sought to conduct a systematic review of the literature to evaluate the association between hemodynamic goals of therapy and patient outcomes.

METHODS

We conducted a comprehensive search of the literature to systematically review hemodynamic goals used in clinical trials in patients with sepsis. We searched the literature using the Pubmed (1965-June 2006), Embase (1974-June 2006), CINAHL (1982-June 2006), pre-CINAHL, and Cochrane Library (2006, issue 3) electronic databases on 1 August 2006 for the following terms: sepsis, septic shock, severe sepsis, human clinical trials. We also hand-searched references and our personal files. Studies were selected if they met all of the following criteria: randomized, controlled trial study design; enrollment of adult patients with sepsis; presence of a hemodynamic goal for patient management; > 24-hour follow-up; and survival included as an outcome. Studies were independently selected and reviewed by two investigators.

RESULTS

A total of 6,006 citations were retrieved, and 13 eligible articles were reviewed. Mean arterial pressure was a treatment goal in nine studies, and systolic blood pressure was a treatment goal in three studies. A goal for pulmonary artery occlusion pressure, central venous pressure, and cardiac index was given in four, three, and five studies, respectively. The range of hemodynamic goals used in the trials were: mean arterial pressure 60-100 mmHg, central venous pressure 6-13 mmHg, pulmonary artery occlusion pressure 13-17 mmHg, and cardiac index 3-6 l/min/m2. All trials that used a systolic blood pressure goal used 90 mmHg as the aim.

CONCLUSION

For those trials that specify hemodynamic goals, the wide range of treatment targets suggest a lack of agreement on blood pressure and filling pressure goals for management of patients with sepsis. There was also inconsistency between trials in which measures were targeted. Further research is necessary to determine whether this lack of consistency in hemodynamic goals may contribute to heterogeneity in treatment effects for clinical trials of novel sepsis therapies.

CHEMICALLY MODIFIED TETRACYCLINE (COL-3) IMPROVES SURVIVAL IF GIVEN 12 BUT NOT 24 HOURS AFTER CECAL LIGATION AND PUNCTURE

Sepsis can result in excessive and maladaptive inflammation that is responsible for more than 215,00 deaths per year in the United State alone. Current strategies for reducing the morbidity and mortality associated with sepsis rely on treatment of the syndrome rather than prophylaxis. We have been investigating a modified tetracycline, COL-3, which can be given prophylactically to patients at high risk for developing sepsis. Our group has shown that COL-3 is very effect at preventing the sequelae of sepsis if given before or immediately after injury in both rat and porcine sepsis models. In this study, we wanted to determine the "treatment window" for COL-3 after injury at which it remains protective. Sepsis was induced by cecal ligation and puncture (CLP). Rats were anesthetized and placed into five groups: CLP (n = 20) = CLP without COL-3, sham (n = 5) = surgery without CLP or COL-3, COL3@6h (n = 10) = COL-3 given by gavage 6 h after CLP, COL3@12h (n = 10) = COL-3 given by gavage 12 h after CLP, and COL3@24h (n = 20) = COL-3 given by gavage 24 h after CLP. COL-3 that was given at 6 and 12 h after CLP significantly improved survival as compared with the CLP and the CLP@24h groups. Improved survival was associated with a significant improvement in lung pathology assessed morphologically. These data suggest that COL-3 can be given up to 12 h after trauma and remain effective.

[Diagnosis and therapy of sepsis. Guidelines of the German Sepsis Society Inc. and the German Interdisciplinary Society for Intensive and Emergency Medicine]

A recent survey conducted by the publicly funded Competence Network Sepsis (SepNet) reveals that severe sepsis and/or septic shock occurs in 75,000 inhabitants (110 out of 100,000) and sepsis in 79,000 inhabitants (116 out of 100,000) in Germany annually. This illness is responsible for approximately 60,000 deaths and ranges as the third most frequent cause of death after acute myocardial infarction. Direct costs for the intensive care of patients with severe sepsis alone amount to approximately 1.77 billion euros, which means that about 30% of the budget in intensive care is used to treat severe sepsis. However, until now German guidelines for the diagnosis and therapy of severe sepsis did not exist. Therefore, the German Sepsis Society initiated the development of guidelines which are based on international recommendations by the International Sepsis Forum (ISF) and the Surviving Sepsis Campaign (SSC) and take into account the structure and organization of the German health care system. Priority was given to the following guideline topics: a) diagnosis, b) prevention, c) causative therapy, d) supportive therapy, e) adjunctive therapy. The guidelines development process was carefully planned and strictly adhered to the requirements of the Working Group of Scientific Medical Societies (AWMF).

The changing epidemiology of acute renal failure

Different definitions of acute renal failure (ARF) abound. The existence of multiple definitions makes it difficult to determine the true epidemiological characteristics of this condition. Despite this difficulty, it has been possible to detect notable variations in the epidemiology of ARF during the past few decades. The absolute incidence of ARF has increased, while associated mortality rate has remained relatively static. Several factors have contributed to this altered epidemiology. Here, we discuss the relative contribution of these factors, which include site of disease onset (developed or developing countries, community or hospital or intensive care unit), patient age, infections (HIV, malaria, leptospirosis and hantavirus), concomitant illnesses (cardiopulmonary failure, hemato-oncological disease), and interventions (hematopoietic progenitor cell and solid organ transplantation).

Apoptosis and caspases regulate death and inflammation in sepsis

Although the prevailing concept has been that mortality in sepsis results from an unbridled hyper-inflammatory cytokine-mediated response, the failure of more than 30 clinical trials to treat sepsis by controlling this cytokine response requires a 'rethink' of the molecular mechanism underpinning the development of sepsis. As we discuss here, remarkable new studies indicate that most deaths from sepsis are actually the result of a substantially impaired immune response that is due to extensive death of immune effector cells. Rectification of this apoptotic-inflammatory imbalance using modulators of caspases and other components of the cell-death pathway have shown striking efficacy in stringent animal models of sepsis, indicating an entirely novel path forward for the clinical treatment of human sepsis.

A Brief Overview of Acute Respiratory Distress Syndrome

BACKGROUND

The low pO: (2) in traumatic and septic shock was first documented at Walter Reed Army Medical Center starting in 1960. It was postulated that this respiratory failure was due to the occlusion of the pulmonary microcirculation by the microclots of disseminated intravascular coagulation (DIC).

MATERIALS AND METHODS

Animal studies showed that pulmonary failure and death could be caused by intravenous injection of a killed culture of either Escherichia coli or pneumococcal organisms or by severe muscle contusion. Severe clinical septic and traumatic shock cases were studied.

RESULTS

Injection of either killed E. coli or killed pneumococci resulted in acute respiratory distress syndrome (ARDS) and death in pigs. Muscle contusion also resulted in ARDS and death in pigs. Both ARDS and death were prevented by administration of a plasminogen activator, and ARDS in human septic or traumatic shock were safely and effectively treated by administration of a plasminogen activator.

CONCLUSIONS

Acute respiratory distress syndrome can be caused by DIC, which blocks the microcirculation of any and all organs. These microclots can be safely lysed by a plasminogen activator, thus treating ARDS and saving lives.

Induction of the heat shock response in vivo inhibits NF-kappaB activity and protects murine liver from endotoxemia-induced injury

Liver plays an important role in the pathogenesis of sepsis by releasing various cytokines and producing acute phase proteins. Heat shock preconditioning is reported to be effective in protection of lung and liver from injury in sepsis and in endotoxemia models, but the exact mechanism is still not fully understood. We report here on the effects of the heat shock response (HSR) induced by sodium arsenite on endotoxemia-induced liver injury as well as hepatic NF-kappaB activation and proinflammatory cytokine expression. Prior induction of HSR significantly attenuated endotoxemia-induced histological changes, inhibited hepatic NF-kappaB activation and IkappaBalpha degradation and decreased mortality. Expression of mRNA coding for TNF-alpha and IL-6 in liver was significantly lower in arsenite-pretreated animals. We conclude that attenuation of endotoxin-induced hepatic NF-kappaB activation and subsequent proinflammatory cytokine production may be one of the mechanisms of the beneficial effect of the heat shock response.

Endotoxin adsorption therapy for septic shock using polymyxin B-immobilized fibers (PMX): evaluation by high-sensitivity endotoxin assay and measurement of the cytokine production capacity

Because of its low sensitivity, the conventional measurement method for endotoxin (ET) is not the most appropriate for monitoring the effect of ET adsorption therapy. Thus, the efficacy of ET adsorption therapy was investigated using a newly developed high-sensitivity ET assay method. The changes in the cytokine production capacity of whole blood were also examined. We treated 24 peritonitis patients who had developed postoperative septic shock with ET adsorption therapy using a column of polymyxin B-immobilized fibers (PMX) and their serum ET levels were measured using the high-sensitivity ET assay based on the kinetic turbidimetric Limulus assay. In addition, the changes in the tumor necrosis factor-(TNF-alpha) production capacity of whole blood following lipopolysaccharide (LPS) stimulation and clinical outcome in the study patients were also examined. The 28-day mortality rate was 12%. PMX-direct hemoperfusion (PMX-DHP) was associated with elevation of the mean arterial pressure and urine output, reduction in the mean dose requirement of vasopressor agents, and recovery from the shock state in all the patients. The PaO2/FIO2 ratio also showed significant improvement. Using the high-sensitivity ET assay, ET was detected in the blood of 20 out of the 24 patients (80%) before the PMX-DHP, and a significant reduction in the ET level was noted after the PMX-DHP. The TNF-alpha production capacity of whole blood, which was found to be lower in the septic shock patients than in healthy subjects, was significantly increased after PMX-DHP. Elimination of ET by PMX-DHP in septic shock patients was confirmed by the high-sensitivity ET assay. PMX-DHP is thus considered to be a useful adjuvant therapeutic technique in the treatment of septic shock. Also, PMX-DHP might alleviate the immunosuppression associated with severe sepsis.

[Diagnosis and therapy of sepsis]

A recent survey conducted by the publicly funded Competence Network Sepsis (Sep- Net) reveals that severe sepsis and/or septic shock occurs in 75,000 inhabitants (110 out of 100,000) and sepsis in 79,000 inhabitants (116 out of 100,000) in Germany annually. This illness is responsible for approx. 60,000 deaths and ranges as the third most frequent cause of death after acute myocardial infarction. Direct costs for the intensive care of patients with severe sepsis alone amount to approx. 1.77 billion euros, which means that about 30% of the budget in intensive care is used to treat severe sepsis. However, until now German guidelines for the diagnosis and therapy of severe sepsis did not exist. Therefore, the German Sepsis Society initiated the development of guidelines which are based on international recommendations by the International Sepsis Forum (ISF) and the Surviving Sepsis Campaign (SSC) and take into account the structure and organisation of the German health care system. Priority was given to the following guideline topics: a) diagnosis, b) prevention, c) causative therapy, d) supportive therapy, e) adjunctive therapy. The guidelines development process was carefully planned and strictly adhered to according to the requirements of the Working Group of Scientific Medical Societies (AWMF).

Sepsis

Sepsis results from the host response to infection. While a localized and controlled inflammatory reaction helps to control infection, a dysregulated response may lead to multiple organ failure and determines the course and prognosis of the septic patient. Despite intensive care, mortality remains as high as 54% for severe sepsis and septic shock. As the mechanisms are becoming better defined, interventions aiming to interfere with the host response have been undertaken, largely with disappointing results. Thus, many evidence-based recommendations suggest waiving of resource-consuming interventions. Nevertheless, several seminal studies have indicated that early and systematic supportive therapy according to pathophysiological principles, most notably early goal-directed therapy, low-dose hydrocortisone and activated protein C, can disrupt dysfunctional cascades and can favourably influence the course of the disease. In parallel, efforts to better define nationwide epidemiology and treatment habits for severe sepsis by the German competence network "SepNet" indicate that therapy of severe sepsis is generally in poor compliance with guidelines, while the personal perception of physicians in charge would suggest high rates of adherence. Thus, strategies of change management, such as implementation of sepsis bundles are warranted to achieve a better standard of care toward the aim of the "surviving sepsis campaign", i.e. a reduction of mortality by 25% within the next 5 years.

Insulin attenuates endotoxin-induced acute lung injury in conscious rats

OBJECTIVES

To investigate the effects of insulin on the acute lung injury induced by lipopolysaccharide using a conscious rat model.

DESIGN

Prospective, randomized, controlled animal study.

SETTING

University research laboratory.

SUBJECTS

A total of 190 adult male Sprague-Dawley rats weighing 250-300 g.

INTERVENTIONS

Endotoxemia was induced by intravenous infusion of lipopolysaccharide. Lipopolysaccharide at various doses (0, 1, 5, 10, 20, and 30 mg/kg, n=10 for each dose) was administered intravenously in 20 mins. Insulin infusion at doses of 0.5, 1, and 5 microU/kg/min was given 5 mins before lipopolysaccharide administration. Plasma glucose was clamped at 90-110 mg/dL by infusion of 10-80% glucose solution. Insulin and glucose infusion (0.01 mL/min) was started 5 mins before lipopolysaccharide and continued for 120 mins. The rats received a total of 60, 120, and 600 microU/kg insulin as well as 0.12, 0.36, and 0.96 g of glucose in respective groups. The animals were then observed for 4 hrs.

MEASUREMENTS AND MAIN RESULTS

The extent of acute lung injury was evaluated by lung weight/body weight ratio, lung weight gain, protein concentration in bronchoalveolar lavage, and exhaled nitric oxide. We also measured plasma nitrate/nitrite and methyl guanidine. In addition, histopathologic changes of the lung were examined. Lipopolysaccharide caused systemic hypotension and severe acute lung injury with increases in plasma nitrate/nitrite and methyl guanidine. Pretreatment with insulin infusion at doses of 0.5, 1, and 5 microU/kg/min mitigated or prevented systemic hypotension and the development of acute lung injury, depending on the dose. Insulin also attenuated the lipopolysaccharide-induced increases in nitrate/nitrite and methyl guanidine.

CONCLUSIONS

Insulin is effective in reducing or preventing the lipopolysaccharide-induced increases in plasma nitrate/nitrite and methyl guanidine and the occurrence of acute lung injury.

A novel adsorbent of circulating bacterial toxins and cytokines: the effect of direct hemoperfusion with CTR column for the treatment of experimental endotoxemia

OBJECTIVES

The current study examined the ability of a new adsorbent, CTR, to remove enterotoxins, toxic shock syndrome toxin-1 (TSST-1), and cytokines from blood and/or serum in vitro and the effects of the extracorporeal treatment with CTR column on mortality rate and inflammatory responses to endotoxic shock in vivo.

DESIGN

Laboratory investigation.

SETTING

University and company experimental laboratory.

MATERIALS

CTR is composed of porous cellulose beads to which a hydrophobic organic compound with a hexadecyl alkyl chain has been covalently bound to the surface as a ligand. Human/bovine serum and human blood samples in vitro and Male Wistar rats were used.

INTERVENTIONS

CTR's ability to adsorb bacterial toxins and cytokines related to sepsis in serum and/or blood was examined with an in vitro batch adsorption protocol. In vivo, male Wistar rats were anesthetized and assigned to one of three groups (n=14 per group): Escherichia coli endotoxin (15 mg/kg intravenously) alone (endotoxemic), apheresis with control column without CTR for 120 mins (control column), or extracorporeal treatment with CTR column for 120 mins (CTR treatment).

MEASUREMENTS AND MAIN RESULTS

With use of the CTR adsorbent, the adsorption rates were 50% to 90% for enterotoxins, TSST-1, and cytokines such as TNF-alpha and interleukin (IL)-6 in the batch tests. In vivo, the mortality rates at 8 hrs after endotoxin injection were 92%, 92%, and 14% for the endotoxemic, control column, and CTR treatment groups, respectively. Hypotension and elevated plasma cytokine concentrations and the infiltration of neutrophils of the lungs were less conspicuous in the CTR treatment group than in the other two groups.

CONCLUSIONS

CTR, a novel adsorbent, effectively adsorbed small- to middle-sized proteins, such as cytokines, enterotoxins, and TSST-1 in vitro. Direct hemoperfusion apheresis with CTR column reduced mortality and had inhibitory effects on the inflammatory responses during endotoxemia in vivo. These findings suggest that extracorporeal blood purification with CTR column may be available to use for patients with sepsis and/or endotoxemia.

Effects of Extracorporeal Treatment With Lixelle on the Mortality and Inflammatory Responses to Endotoxin-Induced Shock in Rats

Endotoxemia and endotoxic shock are common problems in intensive care units and are associated with a very high mortality. Several previous studies have shown that Lixelle, which absorbs beta2-microglobulin for the treatment of dialysis-related amyloidosis, is also useful for the adsorption of inflammatory cytokines and endotoxins. The current study examined the use of Lixelle and its effects on the mortality and inflammatory responses to endotoxin-induced shock in rats. Male Sprague-Dawley rats were anesthetized and assigned to one of four groups (N = 13 per group): Escherichia coli endotoxin (15 mg/kg, i.v.) alone (endotoxemic); direct hemoperfusion apheresis without Lixelle for 120 min (direct hemoperfusion (DHP) alone); Lixelle treatment with Lixelle for 120 min immediately after endotoxin injection (Lixelle treatment); or Lixelle treatment with Lixelle for 120 min 2 h after endotoxin injection (Lixelle post-treatment). Hemodynamics and plasma lactate and cytokine concentrations were measured during observation. Mortality was assessed up to 8 h after the endotoxin injection. The mortality rates at 8 h after endotoxin injection were 92%, 85%, 23% and 46% for the endotoxemic, DHP-alone, Lixelle treatment, and Lixelle post-treatment groups, respectively. Elevated plasma cytokine concentrations were less conspicuous in the Lixelle treatment group than in the other three groups. Thus, Lixelle treatment drastically reduced the high mortality and the inflammatory responses in endotoxin-exposed rats. Moreover, Lixelle post-treatment also suppressed hypotension and a high mortality, although the inflammatory responses were the same as for endotoxin alone. These findings indicate that Lixelle treatment might be an effective therapy for endotoxemia and endotoxic shock.

Cortistatin, a new antiinflammatory peptide with therapeutic effect on lethal endotoxemia

Cortistatin is a recently discovered cyclic neuropeptide related to somatostatin that has emerged as a potential endogenous antiinflammatory factor based on its production by and binding to immune cells. Because human septic shock involves excessive inflammatory cytokine production, we investigated the effect of cortistatin on the production of inflammatory mediators and its therapeutic action in various murine models of endotoxemia. Cortistatin down-regulated the production of inflammatory mediators by endotoxin-activated macrophages. The administration of cortistatin protected against lethality after cecal ligation and puncture, or injection of bacterial endotoxin or Escherichia coli, and prevented the septic shock-associated histopathology, such as infiltration of inflammatory cells and intravascular disseminated coagulation in various target organs. The therapeutic effect of cortistatin was mediated by decreasing the local and systemic levels of a wide spectrum of inflammatory mediators, including cytokines, chemokines, and acute phase proteins. The combined use of cortistatin and other antiinflammatory peptides was very efficient treating murine septic shock. This work provides the first evidence of cortistatin as a new immunomodulatory factor with the capacity to deactivate the inflammatory response. Cortistatin represents a potential multistep therapeutic agent for human septic shock, to be used in combination with other immunomodulatory agents or as a complement to other therapies.

Chemically modified tetracycline prevents the development of septic shock and acute respiratory distress syndrome in a clinically applicable porcine model

Sepsis causes more than with 215,000 deaths per year in the United States alone. Death can be caused by multiple system organ failure, with the lung, in the form of the acute respiratory distress syndrome (ARDS), often being the first organ to fail. We developed a chronic porcine model of septic shock and ARDS and hypothesized that blocking the proteases neutrophil elastase (NE) and matrix metalloproteinases (MMP-2 and MMP-9) with the modified tetracycline, COL-3, would significantly improve morbidity in this model. Pigs were anesthetized and instrumented for hemodynamic monitoring and were then randomized to one of three groups: control (n = 3), laparotomy only; superior mesenteric artery occlusion (SMA) + fecal blood clot (FC; n = 7), with intraperitoneal placement of a FC; and SMA + FC + COL (n = 5), ingestion of COL-3 12 h before injury. Animals emerged from anesthesia and were monitored and treated with fluids and antibiotics in an animal intensive care unit continuously for 48 h. Serum and bronchoalveolar lavage fluid (BALF) were sampled and bacterial cultures, MMP-2, MMP-9, NE, and multiple cytokine concentrations were measured. Pigs were reanesthetized and placed on a ventilator when significant lung impairment occurred (PaO2/FiO2 < 250). At necropsy, lung water and histology were assessed. All animals in the SMA + FC group developed septic shock evidenced by a significant fall in arterial blood pressure that was not responsive to fluids. Lung injury typical of ARDS (i.e., a fall in lung compliance and PaO2/FiO2 ratio and a significant increase in lung water) developed in this group. Additionally, there was a significant increase in plasma IL-1 and IL-6 and in BALF IL-6, IL-8, IL-10, NE, and protein concentration in the SMA + FC group. COL-3 treatment prevented septic shock and ARDS and significantly decreased cytokine levels in plasma and BALF. COL-3 treatment also significantly reduced NE activity (P < 0.05) and reduced MMP-2 and MMP-9 activity in BALF by 64% and 34%, respectively, compared with the SMA + FC group. We conclude that prophylactic COL-3 prevented the development of ARDS and unexpectedly also prevented septic shock in a chronic insidious onset animal model of sepsis-induced ARDS. The mechanism of this protection is unclear, as COL-3 inhibited numerous inflammatory mediators. Nevertheless, COL-3 significantly reduced the morbidity in a clinically applicable animal model, demonstrating the possibility that COL-3 may be useful in reducing the morbidity associated with sepsis and ischemia/reperfusion injury in patients.

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.

HIV-1 Viral Protein-R (VPR) Protects against Lethal Superantigen Challenge While Maintaining Homeostatic T Cell Levels in Vivo

The HIV-1 accessory protein Vpr exhibits many interesting features related to macrophage and T cell biology. As a viral protein or as a soluble molecule it can suppress immune cell activation and cytokine production in vitro in part by targeted inhibition of NF-kappaB. In this regard we sought to test its effects in vivo on an NF-kappaB-dependent immune pathway. We examined the activity of Vpr in a lethal toxin-mediated challenge model in mice. Intravenous delivery of Vpr was sufficient to protect mice from lethal challenge with staphylococcal endotoxin B (SEB). Furthermore, Vpr protected host CD4+ T cells from in vivo depletion likely by preventing induction of AICD of SEB-exposed cells in a post-toxin-binding fashion. Understanding the biology of Vpr's activities in this model may allow for new insight into potential mechanisms of hyperinflammatory disease and into Vpr pathobiology in the context of HIV infection.

Sepsis and coagulation

The host response to infection is a highly complex yet well-orchestrated process that involves an elaborate array of soluble mediators and cells. Normally, the host response prevails in containing and eliminating the pathogenic threat. When excessive or sustained, however, the host response may "turn on its bearer" and lead to organ dysfunction. Severe sepsis is invariably associated with activation of primary and secondary hemostasis. This article describes sepsis-associated changes in coagulation, discusses the putative role for these changes in pathogenesis of the sepsis syndrome, and outlines current diagnostic and therapeutic strategies.

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.

Chemokines provide the sustained inflammatory bridge between innate and acquired immunity

In this review we focus on the role of chemokines in discreet areas of innate immunity and demonstrate that chemokines are key participants to not only the early inflammatory response to a foreign agent, but important to the sustained immune reaction. Our studies support the concept that a concerted and interactive innate and acquired immune reaction is key for an automatic, dynamic, sustained, and regulated response toward clearing foreign stimuli. It is imperative that the in vivo concept of innate and acquired immunity be considered a continuum of a global assault on a foreign agent and not as modes, which are independent of one another.

Novel therapies for sepsis: a review

BACKGROUND

Over the past 30 years, efforts have been made to identify therapeutic targets in the host response to infection.

METHODS

A review of the randomized controlled clinical sepsis trials and meta-analyses of glucocorticoids, mediator-specific anti-inflammatory agents, and anticoagulant agents was performed.

RESULTS

The effects of glucocorticoids in sepsis appear to be dose-dependent, with high doses decreasing survival and low doses improving survival. As a class, the mediator-specific anti-inflammatory agents have a small beneficial effect on survival; however, no single agent has demonstrated significant benefit. The treatment effects of these agents appear to be related to the patient's risk of death. As a class, the anticoagulant agents do not improve survival; however, the efficacy of these agents may have been confounded by concurrent heparin therapy. Activated protein C demonstrated a beneficial effect on survival that was dependent on severity of illness.

CONCLUSION

Trials of agents directed at altering the host's response during sepsis have had variable results, and it appears that several different factors may alter the efficacy of these agents.

Concept of PIRO as a new conceptual framework to understand sepsis

OBJECTIVE

To define and introduce the PIRO model for categorizing sepsis in infants and children.

DESIGN

A summary of the literature published during the 5 yrs since this concept has been formulated, along with a consensus opinion of experts in the field of sepsis and septic shock.

RESULTS

The imprecision and intrinsic heterogeneity of the patient population defined as septic has prompted the introduction of a new sepsis classification system known as PIRO. PIRO stands for predisposition, infection, response, and organ dysfunction. It is hoped that by defining the septic process through a detailed analysis of each of its component parts, the development of sepsis will be better understood. This may contribute to improved therapeutic interventions for sepsis in the future.

CONCLUSIONS

The PIRO model is a conceptual framework for understanding sepsis that has many favorable attributes. The PIRO model should be directly tested in both the research laboratory and in clinical trial designs to determine the practical value and clinical relevance of this new classification scheme for sepsis.

Lipopolysaccharide sequestrants: structural correlates of activity and toxicity in novel acylhomospermines

Lipopolysaccharides (LPS), otherwise termed "endotoxins", are outer membrane constituents of Gram-negative bacteria. Lipopolysaccharides play a key role in the pathogenesis of "septic shock", a major cause of mortality in the critically ill patient. Therapeutic options aimed at limiting downstream systemic inflammatory processes by targeting lipopolysaccharide do not exist at the present time. We have defined the pharmacophore necessary for small molecules to specifically bind and neutralize LPS and, using animal models of sepsis, have shown that the sequestration of circulatory LPS by small molecules is a therapeutically viable strategy. In this paper, the interactions of a series of acylated homologated spermine compounds with LPS have been characterized. The optimal acyl chain length for effective sequestration of LPS was identified to be C(16) for the monoacyl compounds. The most promising of these compounds, 4e, binds LPS with an ED(50) of 1.37 muM. Nitric oxide production in murine J774A.1 cells, as well as TNF-alpha in human blood, is inhibited in a dose-dependent manner by 4e at concentrations orders of magnitude lower than toxic doses. Administration of 4e to d-galactosamine-sensitized mice challenged with supralethal doses of LPS provided significant protection against lethality. Potent antiendotoxic activity, low toxicity, and ease of synthesis render this class of compounds candidate endotoxin-sequestering agents of potential significant therapeutic value.

The activities of monocyte lysophosphatidylcholine acyltransferase and coenzyme A-independent transacylase are changed by the inflammatory cytokines tumor necrosis factor alpha and interferon gamma

Alteration of membrane phospholipid fatty acid compositions has been shown to be important for leukocyte inflammatory responses. Such modification of the molecular species of these lipid classes requires deacylation and reacylation reactions and for phosphatidylcholines, lysophosphatidylcholine acyltransferase (LPCAT) and a coenzyme A-independent transacylase (CoAIT) can each be involved. Since previous studies have shown a significant IFNgamma- and TNFalpha-induced modification of phosphatidylcholine species, we have examined whether these inflammatory cytokines alter the activity of reacylation enzymes in the human monocyte cell line MonoMac 6 (MM6). IFN-gamma caused a significant increase in the activity of the LPCAT and CoAIT enzymes in the microsomal fraction at concentrations and over a time-course consistent with an important role for these enzymes in the sensitization (priming) of monocytes. In contrast, TNFalpha was found to significantly increase the activity of the CoAIT by 50% over controls in MM6 cells after 30 min incubation with the cytokine, but decreased LPCAT activity by 65% after 24 h incubation. Such data imply that CoAIT is important for the remodelling of phospholipid composition, which is seen during the acute response of cells to TNFalpha. The results provide further information to emphasise the role of acyltransferases as part of the molecular mechanism underlying inflammation.

Role of chemically modified tetracycline on TNF-alpha and mitogen-activated protein kinases in sepsis

Chemically modified tetracyclines are orally active inhibitors of multiple proteases and cytokines. In this study, we focused on the regulation of tumor necrosis factor (TNF)-alpha and mitogen-activated protein kinases (MAPKs) in sepsis and their reduction by treatment with nonantimicrobial chemically modified tetracycline-3 (CMT-3), which retains their antiinflammatory activity. Sepsis was induced in rats by cecal ligation and puncture (CLP). At 24 h and 1 h before CLP, treated rats received CMT-3 (25 mg/kg), and untreated rats received saline by gavage. At 0 h, 0.5 h, 1.5 h, and 24 h after CLP, blood and liver samples were collected. TNF-alpha was determined by ELISA, and MAPKs were determined by Western blot analysis. A significant activation of p38 MAPK was observed after 0.5 h and 1.5 h of sepsis that appeared to coincide with the increased circulating TNF-alpha level. The activation of p42/44 was increased after 24 h of sepsis, whereas that of SAPK/JNK was unaltered throughout the course of sepsis. CMT-3 pretreatment inhibited the TNF-alpha level as well as p38 MAPK activation seen after 0.5 and 1.5 h of CLP and also suppressed the activation of p42/44 after 24 h post-CLP. These results indicate increased activity of TNF-alpha and MAPK following sepsis and demonstrate the beneficial effect of CMT-3 in preventing the increase in TNF-alpha, p38 MAPK, p42/44 MAPK, and the progression of septic shock.

Antimicrobial therapy for patients with severe sepsis and septic shock: an evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for antimicrobial therapy for patients with severe sepsis and septic shock that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

Since the prompt institution of therapy that is active against the causative pathogen is one of the most important predictors of outcome, clinicians must establish a system for rapid administration of a rationally chosen drug or combination of drugs when sepsis or septic shock is suspected. The expanding number of antibacterial, antifungal, and antiviral agents available provides opportunities for effective empiric and specific therapy. However, to minimize the promotion of antimicrobial resistance and cost and to maximize efficacy, detailed knowledge of the likely pathogens and the properties of the available drugs is necessary for the intensivist.

Methods of monitoring shock

Intensive monitoring is a crucial component of the management of shock. However, there is little consensus about optimal strategies for monitoring. Although the pulmonary artery catheter has been widely used, conflicting data exist about the utility of this device. A variety of other techniques have been developed in hopes of providing clinically useful information about myocardial function, intravascular volume, and indices of organ function. In addition, there is evolving evidence that targeting and monitoring certain physiological goals may be most important early in the course of shock. In this chapter, we examine many of the available monitoring techniques and the evidence supporting their use.