Sepsis: state of the art

Stress-Induced Hyperglycemia: Consequences and Management

Hyperglycemia during stress is a common occurrence seen in patients admitted to the hospital. It is defined as a blood glucose level above 180mg/dl in patients without pre-existing diabetes. Stress-induced hyperglycemia (SIH) occurs due to an illness that leads to insulin resistance and decreased insulin secretion. Such a mechanism causes elevated blood glucose and produces a complex state to manage with external insulin. This article compiles various studies to explain the development and consequences of SIH in the critically ill that ultimately lead to an increase in mortality while also discussing the dire impact of SIH on certain acute illnesses like myocardial infarction and ischemic stroke. It also evaluates multiple studies to understand the management of SIH with insulin and proper nutritional therapy in the hospitalized patients admitted to the Intensive care unit (ICU) alongside the non-critical care unit. While emphasizing the diverse effects of improper control of SIH in the hospital, this article elucidates and discusses the importance of formulating a discharge plan due to an increased risk of type 2 diabetes in the recovered. 

Research Progress in Chinese Herbal Medicines for Treatment of Sepsis: Pharmacological Action, Phytochemistry, and Pharmacokinetics

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection; the pathophysiology of sepsis is complex. The incidence of sepsis is steadily increasing, with worldwide mortality ranging between 30% and 50%. Current treatment approaches mainly rely on the timely and appropriate administration of antimicrobials and supportive therapies, but the search for pharmacotherapies modulating the host response has been unsuccessful. Chinese herbal medicines, i.e., Chinese patent medicines, Chinese herbal prescriptions, and single Chinese herbs, play an important role in the treatment of sepsis through multicomponent, multipathway, and multitargeting abilities and have been officially recommended for the management of COVID-19. Chinese herbal medicines have therapeutic actions promising for the treatment of sepsis; basic scientific research on these medicines is increasing. However, the material bases of most Chinese herbal medicines and their underlying mechanisms of action have not yet been fully elucidated. This review summarizes the current studies of Chinese herbal medicines used for the treatment of sepsis in terms of clinical efficacy and safety, pharmacological activity, phytochemistry, bioactive constituents, mechanisms of action, and pharmacokinetics, to provide an important foundation for clarifying the pathogenesis of sepsis and developing novel antisepsis drugs based on Chinese herbal medicines.

Prognostic factors for descending necrotizing mediastinitis development in deep space neck infections-a retrospective study

OBJECTIVES

Descending necrotizing mediastinitis (DNM) is the most serious complication of deep neck infections (DNI). The objective of this retrospective study was to evaluate prognostic factors for DNM development in deep space neck infections.

METHODS

The study enrolled patients admitted to the Emergency Center of Vojvodina with the diagnosis of multispace DNI with or without DNM either as the primary diagnosis or with discharged diagnosis after surgical treatment during 7-year period. The data were obtained from patient medical records.

RESULTS

After final analysis total of 141 charts were randomized for statystical analysis, 124 charts in DNI and 17 in DNI + DNM groups. The most common cause of infection in both groups was odontogenic. On multivariate regression analysis of collected data infection of retropharyngeal, pretracheal and carotid space, C-reactive protein and procalcitonine values were statistically significant predictors for DNM development.

CONCLUSIONS

Treatment and diagnosis of DNM requires multidisciplinary approach, with prompt clinical and radiological examinations, empirical broad spectrum antibiotic therapy and radical surgical debridement. Multispace neck infection and especially infection of retropharyngeal, carotid and pretracheal spaces are the most sensitive predictors for DNM development in deep space neck infections.

CLINICAL RELEVANCE

If the infection from deep neck spaces reach retropharyngeal, carotid or pretracheal space, the DNM is probable to occur.

TRIAL REGISTRATION

ClinicalTrials.gov ID NCT04865003. Date of registration 27.4.2021.

Cardiovascular biomarkers in dogs with systemic inflammatory response syndrome

OBJECTIVE

To measure plasma N-terminal fragments of pro-B-type natriuretic peptides (NT-proBNP) and cardiac troponin T (cTnT) concentration in hospitalized dogs and relate these markers to underlying conditions and evaluate their potential as prognostic markers in dogs with systemic inflammatory response syndrome (SIRS).

DESIGN

Prospective, observational, clinical study.

SETTING

Emergency department of a university teaching hospital.

ANIMALS

Sixty-nine dogs with SIRS examined in the emergency department were prospectively studied. Patient age ranged from 5 months to 15 years, and weight ranged from 5.5 to 75 kg.

MEASUREMENTS AND MAIN RESULTS

Blood samples were obtained at presentation, during hospitalization until discharge or death, and at a "control" visit (T1m) at least 1 month after hospital discharge. NT-proBNP was assayed with a commercially available canine ELISA, while cTnT was measured with an automated immunoassay previously used in dogs. A correlation procedure, mixed procedure on a linear model, and a logistic procedure were performed. Forty-four patients survived, 19 of which had control visits. cTnT concentrations were significantly higher than T0 and T1m at T12, T24, and T72. In 28 dogs, cTnT was detected during hospitalization, but cTnT was not detected in any dog at the control visits. Higher concentrations of cTnT were negatively associated with survival, irrespective of disease category. NT-proBNP concentrations were significantly higher than T0, T6, T12, and T1m at T24, T72, and T120, but were not associated with survival.

CONCLUSIONS

NT-proBNP and cTnT increased significantly in dogs with SIRS, regardless of the underlying disease process. Nonsurvivors displayed significantly higher cTnT concentrations during hospitalization.

[Septic shock in intensive care units. Current focus on treatment]

Essential therapeutic principles in children with septic shock persist over time, although some new concepts have been recently incorporated, and fully awareness of pediatricians and intensivists is essential. Fluid resuscitation is a fundamental intervention, but the kind of ideal fluid has not been established yet, as each of these interventions has specific limitations and there is no evidence supportive of the superiority of one type of fluid. Should septic shock persists despite adequate fluid resuscitation, the use of inotropic medication and/or vasopressors is indicated. New vasoactive drugs can be used in refractory septic shock caused by vasopressors, and the use of hydrocortisone should be considered in children with suspected adrenal insufficiency, as it reduces the need for vasopressors. The indications for red blood cells transfusion or the optimal level of glycemia are still controversial, with no consensus on the threshold value for the use of these blood products or the initiation of insulin administration, respectively. Likewise, the use of high-volume hemofiltration is a controversial issue and further study is needed on the routine recommendation in the course of septic shock. Nutritional support is crucial, as malnutrition is a serious complication that should be properly prevented and treated. The aim of this paper is to provide update on the most recent advances as concerns the treatment of septic shock in the pediatric population.

Glutamine treatment attenuates hyperglycemia-induced mitochondrial stress and apoptosis in umbilical vein endothelial cells

OBJECTIVE

The aim of this study was to determine the in vitro effect of glutamine and insulin on apoptosis, mitochondrial membrane potential, cell permeability, and inflammatory cytokines in hyperglycemic umbilical vein endothelial cells.

MATERIALS AND METHODS

Human umbilical vein endothelial cells were grown and subjected to glutamine and insulin to examine the effects of these agents on the hyperglycemic state. Mitochondrial function and the production of inflammatory cytokines were assessed using fluorescence analysis and multiple cytotoxicity assays. Apoptosis was analyzed by the terminal deoxynucleotidyl transferase dUTP nick end-labeling assay.

RESULTS

Glutamine maintains the integrity of the mitochondria by reducing the cell permeability and cytochrome c levels and increasing the mitochondrial membrane potential. The cytochrome c level was significantly (p<0.005) reduced when the cells were treated with glutamine. An apoptosis assay revealed significantly reduced apoptosis (p<0.005) in the glutamine-treated cells. Moreover, glutamine alone or in combination with insulin modulated inflammatory cytokine levels. Interleukin-10, interleukin-6, and vascular endothelial growth factor were up-regulated while tumor necrosis factor-α was down-regulated after treatment with glutamine.

CONCLUSION

Glutamine, either alone or in combination with insulin, can positively modulate the mitochondrial stress and cell permeability in umbilical vein endothelial cells. Glutamine regulates the expression of inflammatory cytokines and maintains the balance of the mitochondria in a cytoprotective manner.

Evaluation of prognostic value of selected biochemical markers in surgically treated patients with acute mediastinitis

BACKGROUND

Monitoring of biochemical markers of inflammation in acute mediastinitis (AM) can be useful in the modification of treatment. This study was a retrospective evaluation of selected biochemical parameters with negative impact on the prognosis in surgically treated patients.

MATERIAL/METHODS

There were 44 consecutive patients treated surgically due to AM of differentiated etiology. Selected biochemical markers (WBC, RBC, HGB, HCT, PLT, CRP, PCT, ionogram, protein and albumins) were assessed before surgery and on the 3rd day after surgery. ANOVA was applied to find factors influencing observations. Numerical data [laboratory parameters] were compared by means of medians.

RESULTS

The overall hospital mortality rate was 31.82%. In the group of dead patients, there were observed statistically significant lower mean preoperative values of RBC [p=0.0090], HGB [p=0.0286], HCT [p=0.0354], protein [p= 0.0037], albumins [p=0.0003] and sodium [p<0.0001] and elevated values of CRP [P=0.0107] and PCT p<0.0001]. High level of inflammatory markers on day 3 after surgery was found to increase the risk of death - for WBC (by 67%), for CRP (by 88%) and for PCT (by 100%).

CONCLUSIONS

Poor prognosis was more frequent in patients with preoperative high levels of CRP, PCT, anemia, hypoproteinemia and hyponatremia. The risk of death increases significantly if in the immediate postoperative period no distinct decrease in WBC count and of the CRP and PCT level is observed. In such a situation the patients should be qualified earlier for broadened diagnostic workup and for reoperation.

The PRECISE RCT: evolution of an early septic shock fluid resuscitation trial

Severe sepsis and septic shock are the most common reasons for admission to an intensive care unit; and the risk of death is substantial, estimated at approximately 40%. Evidence suggests that early resuscitation strategies that include the use of resuscitation fluids, antibiotics, blood, and inotropes reduce death. Although fluid resuscitation is an immediate life-saving intervention, a fundamental question that remains unanswered is whether the type of resuscitation fluid impacts survival when it is initiated very early in the course of septic shock. A randomized controlled trial published in 2008 confirmed that hydroxyethyl starch fluids cause acute renal failure defined by the requirement for renal replacement therapy. In contrast, a subgroup analysis from a randomized controlled trial suggests that 4% albumin fluid may reduce death from severe sepsis; however, these findings require confirmation in a large randomized trial. Our team is planning a pragmatic early septic shock fluid resuscitation trial that will compare the effectiveness of 5% albumin vs normal saline on 90-day mortality (PRECISE). In this article, we summarize the scientific rationale and inherent challenges associated with the conduct of PRECISE, the background work and planning elements that have been undertaken, and the PRECISE RCT protocol with rationale and justifications provided for the chosen population, the interventions, and the outcome measures.

Toll-like receptor 2 mediates inhibition of HCO(3)(-) absorption by bacterial lipoprotein in medullary thick ascending limb

Bacterial infection and sepsis are associated with renal tubule dysfunction and dysregulation of systemic electrolyte balance but the underlying mechanisms are incompletely understood. Recently, we demonstrated that HCO(3)(-) absorption by the medullary thick ascending limb (MTAL) is inhibited by gram-negative bacterial LPS through activation of Toll-like receptor 4 (TLR4). Here, we examined whether MTAL transport is altered by activation of TLR2, the receptor predominantly responsible for recognizing gram-positive bacteria. Confocal immunofluorescence showed expression of TLR2 in the basolateral membrane domain of rat and mouse MTALs. The functional role of TLR2 was examined in perfused MTALs using Pam(3)CSK(4), a bacterial lipoprotein analog that specifically activates TLR2. Adding Pam(3)CSK(4) to the bath decreased HCO(3)(-) absorption by 25%. The inhibition by Pam(3)CSK(4) was eliminated in MTALs from TLR2(-/-) mice. HCO(3)(-) absorption was also inhibited by the TLR2 agonists lipoteichoic acid and peptidoglycan, two cell wall components of gram-positive bacteria. The MEK/ERK inhibitor U0126 eliminated inhibition of HCO(3)(-) absorption by bath LPS but had no effect on inhibition by Pam(3)CSK(4). The inhibition by Pam(3)CSK(4) was eliminated by the protein kinase C inhibitors chelerythrine Cl and bisindolylmaleimide. Moreover, the inhibition by Pam(3)CSK(4), lipoteichoic acid, and peptidoglycan was additive to inhibition by LPS. Thus, agonists of basolateral TLR2 and TLR4 inhibit HCO(3)(-) absorption independently through distinct signaling pathways. We conclude that bacterial components act directly through TLRs to modify the transport function of renal tubules. During polymicrobial sepsis, gram-positive bacterial molecules acting through TLR2 and gram-negative LPS acting through TLR4 can function through parallel signaling pathways to impair MTAL transport. The inhibition of luminal acidification may impair the ability of the kidneys to correct systemic acidosis that contributes to sepsis pathogenesis.

Clinical review: a review and analysis of heart rate variability and the diagnosis and prognosis of infection

Bacterial infection leading to organ failure is the most common cause of death in critically ill patients. Early diagnosis and expeditious treatment is a cornerstone of therapy. Evaluating the systemic host response to infection as a complex system provides novel insights: however, bedside application with clinical value remains wanting. Providing an integrative measure of an altered host response, the patterns and character of heart rate fluctuations measured over intervals-in-time may be analysed with a panel of mathematical techniques that quantify overall fluctuation, spectral composition, scale-free variation, and degree of irregularity or complexity. Using these techniques, heart rate variability (HRV) has been documented to be both altered in the presence of systemic infection, and correlated with its severity. In this review and analysis, we evaluate the use of HRV monitoring to provide early diagnosis of infection, document the prognostic implications of altered HRV in infection, identify current limitations, highlight future research challenges, and propose improvement strategies. Given existing evidence and potential for further technological advances, we believe that longitudinal, individualized, and comprehensive HRV monitoring in critically ill patients at risk for or with existing infection offers a means to harness the clinical potential of this bedside application of complex systems science.

Continuous multi-parameter heart rate variability analysis heralds onset of sepsis in adults

BACKGROUND

Early diagnosis of sepsis enables timely resuscitation and antibiotics and prevents subsequent morbidity and mortality. Clinical approaches relying on point-in-time analysis of vital signs or lab values are often insensitive, non-specific and late diagnostic markers of sepsis. Exploring otherwise hidden information within intervals-in-time, heart rate variability (HRV) has been documented to be both altered in the presence of sepsis, and correlated with its severity. We hypothesized that by continuously tracking individual patient HRV over time in patients as they develop sepsis, we would demonstrate reduced HRV in association with the onset of sepsis.

METHODOLOGY/PRINCIPAL FINDINGS

We monitored heart rate continuously in adult bone marrow transplant (BMT) patients (n = 21) beginning a day before their BMT and continuing until recovery or withdrawal (12+/-4 days). We characterized HRV continuously over time with a panel of time, frequency, complexity, and scale-invariant domain techniques. We defined baseline HRV as mean variability for the first 24 h of monitoring and studied individual and population average percentage change (from baseline) over time in diverse HRV metrics, in comparison with the time of clinical diagnosis and treatment of sepsis (defined as systemic inflammatory response syndrome along with clinically suspected infection requiring treatment). Of the 21 patients enrolled, 4 patients withdrew, leaving 17 patients who completed the study. Fourteen patients developed sepsis requiring antibiotic therapy, whereas 3 did not. On average, for 12 out of 14 infected patients, a significant (25%) reduction prior to the clinical diagnosis and treatment of sepsis was observed in standard deviation, root mean square successive difference, sample and multiscale entropy, fast Fourier transform, detrended fluctuation analysis, and wavelet variability metrics. For infected patients (n = 14), wavelet HRV demonstrated a 25% drop from baseline 35 h prior to sepsis on average. For 3 out of 3 non-infected patients, all measures, except root mean square successive difference and entropy, showed no significant reduction. Significant correlation was present amongst these HRV metrics for the entire population.

CONCLUSIONS/SIGNIFICANCE

Continuous HRV monitoring is feasible in ambulatory patients, demonstrates significant HRV alteration in individual patients in association with, and prior to clinical diagnosis and treatment of sepsis, and merits further investigation as a means of providing early warning of sepsis.

Fluid resuscitation in the management of early septic shock (FINESS): a randomized controlled feasibility trial

BACKGROUND

It is unknown whether fluid resuscitation with colloid or crystalloid in patients with severe sepsis or septic shock is associated with an improvement in clinical outcome. This randomized controlled trial determined the feasibility of conducting a large trial testing resuscitation with pentastarch vs normal saline in early septic shock, powered for a difference in mortality.

METHODS

At three Canadian and one New Zealand academic centre, 40 patients with early septic shock defined by at least two systemic inflammatory response syndrome criteria, infectious source, and persistent hypotension after >or= 1 L of crystalloid fluid were recruited. Feasibility measures were patient recruitment, blinding of the study fluids, and acceptability of the goal directed algorithms. Boluses of blinded normal saline or pentastarch (500 mL - maximum 3 L or 28 mL x kg(-1)) were administered within goal directed care for the first 12 hr.

RESULTS

Of 161 patients screened, 121 were excluded and 40 patients were enrolled, for a recruitment rate of 0.75 patients/site/month. Only 57% of physicians and 54% of nurses correctly guessed the study fluid (P = 0.46 and P = 0.67, respectively). The goal directed algorithms were acceptable to 97% of physicians.

CONCLUSION

The ability to recruit patients in this pilot randomized controlled trial was below expectations. Blinding of study fluids was adequate, and resuscitation algorithms were acceptable to most physicians. Methods to improve recruitment are required to enhance the feasibility of conducting a multicentre fluid resuscitation trial in early septic shock.

A survey of Canadian intensivists' resuscitation practices in early septic shock

Introduction

Recent evidence suggests that early, aggressive resuscitation in patients with septic shock reduces mortality. The objective of this survey was to characterize reported resuscitation practices of Canadian physicians caring for adult critically ill patients with early septic shock.

Methods

A scenario-based self-administered national survey was sent out to Canadian critical care physicians. One hypothetical scenario was developed to obtain information on several aspects of resuscitation in early septic shock, including monitoring and resuscitation end-points, fluid administration, red blood cell transfusion triggers, and use of inotropes. The sampling frame was physician members of Canadian national and provincial critical care societies.

Results

The survey response rate was 232 out of 355 (65.3%). Medicine was the most common primary specialty (60.0%), most respondents had practiced for 6 to 10 years (30.0%), and 82.0% were male. The following monitoring devices/parameters were reported as used/measured 'often' or 'always' by at least 89% of respondents: oxygen saturation (100%), Foley catheters (100%), arterial blood pressure lines (96.6%), telemetry (94.3%), and central venous pressure (89.2%). Continuous monitoring of central venous oxygen saturation was employed 'often' or 'always' by 9.8% of respondents. The two most commonly cited resuscitation end-points were urine output (96.5%) and blood pressure (91.8%). Over half of respondents used normal saline (84.5%), Ringers lactate (52.2%), and pentastarch (51.3%) 'often' or 'always' for early fluid resuscitation. In contrast, 5% and 25% albumin solutions were cited as used 'often' or 'always' by 3.9% and 1.3% of respondents, respectively. Compared with internists, surgeons and anesthesiologists (odds ratio (95% confidence interval): 9.8 (2.9 to 32.7) and 3.8 (1.7 to 8.7), respectively) reported greater use of Ringers lactate. In the setting of a low central venous oxygen saturation, 52.5% of respondents reported use of inotropic support 'often' or 'always'. Only 7.6% of physicians stated they would use a red blood cell transfusion trigger of 100 g/l to optimize oxygen delivery further.

Conclusion

Our survey results suggest that there is substantial practice variation in the resuscitation of adult patients with early septic shock. More randomized trials are needed to determine the optimal approach.

Resuscitating patients with early severe sepsis: a Canadian multicentre observational study

BACKGROUND

Fluid resuscitation is a key factor in restoring hemodynamic stability and tissue perfusion in patients with severe sepsis. We sought to examine associations of the quantity and type of fluid administered in the first six hours after identification of severe sepsis and hospital mortality, intensive care unit (ICU) mortality, and organ failure.

METHODS

A retrospective, multicentre cohort study was undertaken at five Canadian tertiary care ICUs. We identified patients with severe sepsis admitted to the ICU between July 1, 2000, and June 30, 2002, using both administrative and clinical databases. Patients were included if they were hypotensive, had an infectious source, and at least two systemic inflammatory response syndrome criteria. We recorded total quantity and type of fluid administered for the first six hours after severe sepsis was identified. The first episode of hypotension defined the starting point for collection of fluid data. Multivariable regression analyses were performed to examine associations between quantity and type of fluid administered and hospital/ICU mortality, and organ failure.

RESULTS

Of 2,026 potentially eligible patient charts identified, 496 patients met eligibility criteria. The mean age and Acute Physiology and Chronic Health Evaluation score (APACHE II) were 61.8 +/- 16.5 yr and 29.0 +/- 8.0, respectively. No associations between quantity or type of fluid administered and hospital mortality or ICU mortality were identified, and there were no statistically significant associations between quantity or type of fluid administered and organ failure. However, more fluid resuscitation was associated with an increased risk of cardiovascular failure [odds ratio (OR) and 95% confidence interval (CI)] for 2-4 L 1.67 (1.03-2.70) and > 4 L 2.34 (1.23-4.44) and a reduced risk of renal failure [OR, 95% CI for 2-4 L 0.48 (0.28-0.83) and > 4 L 0.45 (0.22-0.92)] in the first 24 hr of severe sepsis. Administration of colloid and crystalloid fluid as compared to crystalloid fluid alone was associated with a lower risk of renal failure [OR, 95% CI 0.45 (0.26 to 0.76)].

CONCLUSION

An association between hospital mortality and quantity or type of fluid administered in the first six hours after the diagnosis of severe sepsis was not identifiable. These findings should be considered as hypothesis-generating and warrant confirmation or refutation by randomized controlled trials.

The peri-microvascular edema in hippocampal CA1 area in a rat model of sepsis

Encephalopathy is a common complication of sepsis. However, little is known about the morphological changes that occur in the brain during sepsis. In this study, fecal peritonitis was induced in Wistar rats, which had been monitored for 4 h before their brains were removed and samples from the CA1 area taken. In addition to higher blood pressure with a decreasing pattern and a significant drop in rectal temperature, an increased heart rate and marked respiratory failure were observed. The tissue was investigated and compared with corresponding hippocampal samples taken from sham-operated and not operated control groups. Significantly more peri-microvascular edema was found in the hippocampal CA1 area in the septic group. The percentages of the peri-microvascular edema were 158.57 +/- 3.6%, 122.84 +/- 1.5% and 120.24 +/- 1.9% in the fecal peritonitis group, sham-operated and not operated control groups, respectively. The results may suggest that the edema observed around the microvessels may participate in the pathogenesis of the septic encephalopathy probably by causing in the microvascular permeability characteristics.

Cytokine production and hospital mortality in patients with sepsis-induced stress hyperglycemia

OBJECTIVES

To investigate whether stress hyperglycemia affects the production of the main pro- and anti-inflammatory cytokines and the 28-day hospital mortality in patients with severe sepsis.

METHODS

The study included 62 patients with severe sepsis, divided in three groups according to their glycemic profile within 24h after admission: patients with stress hyperglycemia (group SH, n=16), diabetes mellitus type II (group DM, n=27), and normal glucose levels (group NG, n=19). The serum levels of the cytokines TNF-alpha, IL-6, IL-10 and TGFbeta-1 were measured within 24h after admission.

RESULTS

A higher percentage of septic patients with stress hyperglycemia died compared to diabetic patients (43.7 vs. 14.8%) and group NG (43.7 vs. 5.2%). Group SH had higher SOFA score and levels of IL-6 and IL-10 than group DM and group NG. It also had higher levels of TNF-alpha than group DM but not group NG. There was no difference in the levels of TGFbeta-1 among the three groups. Non-survivors had higher levels of IL-10, no difference was detected for IL-6, TNF-alpha, IL-10/TNF-alpha ratio and TGFbeta-1. Interleukin-10 values, mean fasting glucose values and age were found as prognostic factors associated with outcome.

CONCLUSIONS

Stress hyperglycemia is associated with increased cytokine production and an adverse clinical outcome in patients with severe sepsis.

Management of sepsis during the early "golden hours"

Severe sepsis and septic shock are common causes of morbidity and mortality. Interventions directed at specific endpoints, when initiated early in the "golden hours" of patient arrival at the hospital, seem to be promising. Early hemodynamic optimization, administration of appropriate antimicrobial therapy, and effective source control of infection are the cornerstones of successful management. In patients with vasopressor-dependent septic shock, provision of physiologic doses of replacement steroids may result in improved survival. Administration of drotrecogin alfa (activated), (activated protein C) has been shown to improve survival in patients with severe sepsis and septic shock who have a high risk of mortality. In this article we review the multi-modality approach to early diagnosis and intervention in the therapy of patients with severe sepsis and septic shock.

Endotoxin-induced heart dysfunction in rats: assessment of myocardial perfusion and permeability and the role of fluid resuscitation

OBJECTIVE

The pathophysiology of sepsis-induced myocardial dysfunction is still controversial. Whether microcirculatory hypoperfusion together with capillary leakage can occur in the heart wall also remains a matter of debate. The objective was to evaluate the impact of fluid resuscitation on endotoxin-induced myocardial dysfunction.

DESIGN

Adult rats were given intraperitoneal injection of endotoxin (lipopolysaccharide, Escherichia coli, 10 mg/kg) or phosphate-buffered solution, followed up by echocardiography and acetate micro-positron emission tomography scan imaging, together with final hemodynamic, biochemical, and pathologic evaluations up to 48 hrs.

SETTING

University laboratory.

SUBJECTS

Pathogen-free male Wistar rats (350 g).

INTERVENTIONS

Influence of isovolumic fluid infusion type (saline vs. pentastarch) on these variables was assessed in 11 groups of six animals including an unchallenged control one.

MEASUREMENTS AND MAIN RESULTS

Endotoxin injection induced a) myocardial dysfunction (decrease of approximately 15-20% in left ventricular ejection fraction); b) ventricular enlargement (approximately 1.5- to 1.7-fold increase in left ventricular systolic volume); c) cardiac output increase (10-15%); d) myocardial hypoperfusion ( approximately 1.5- to 2-fold decrease in acetate k1 constant rate); e) increased oxygen consumption (k2); and f) interstitial wall increase. Endotoxin injection also enhanced levels of arterial lactates and troponin I. Colloid (pentastarch) over crystalloid (saline) fluid resuscitation significantly reversed echocardiographic changes, some positron emission tomography imaging alterations, and lactate and troponin I levels without further enhancing interstitial spaces.

CONCLUSION

Endotoxin can induce reversible myocardial alterations with evidence of coronary hypoperfusion and heart wall enlargement/damage, some of which can be prevented by fluid resuscitation. The use of crystalloids is less beneficial than pentastarch.

Monitoring therapeutic interventions in critically ill septic patients

Sepsis is the leading cause of admission to intensive care units in the United States. Although the treatment of sepsis is complex and multimodal, nutrition support plays an important role in the management of these patients. The diagnosis of sepsis, disease category, and severity of illness and the change in sepsis severity and organ function over time affect the delivery of nutrition support. This paper reviews the diagnostic criteria of sepsis, the use of "sepsis biomarkers," and regional and global markers of organ function in sepsis and quantitative measures of illness severity and organ dysfunction.

Current concepts in the diagnosis and management of trauma-related sepsis

Traumatic injury is common, and accounts for a large health care burden. Trauma and in particular haemorrhagic shock are closely related to the onset of multiple organ failure, the systemic inflammatory response and sepsis. Despite overall improvements in the care of septic critically ill patients there has been little impact on morbidity and mortality. In recent years our understanding of sepsis both as an illness and at a molecular level has led to the development of a number of therapeutic interventions. This article outlines the current evidence for such interventions and points to possible future research that is required in the diagnosis and management of trauma-related sepsis.

Adrenal insufficiency during septic shock

OBJECTIVE

To determine whether a baseline (random) cortisol concentration <25 microg/dL in patients with septic shock was a better discriminator of adrenal insufficiency than the standard (250 microg) and the low-dose (1 microg) corticotropin stimulation tests as assessed by the hemodynamic response to steroid replacement.

SETTING

Intensive care unit.

PATIENTS

Fifty-nine patients with septic shock. Their mean age was 57 +/- 16.7 yrs; 29 were male.

INTERVENTIONS

A baseline cortisol concentration was obtained. Patients then received an intravenous injection of 1 microg of corticotropin (low-dose test) followed 60 mins later by an injection of 249 microg of corticotropin (high-dose test). Cortisol concentrations were obtained 30 and 60 mins after low- and high-dose corticotropin. All patients were administered hydrocortisone (100 mg every 8 hrs) for the first 24 hrs while awaiting results of cortisol assessment. Patients were considered steroid responsive if the pressor agent could be discontinued within 24 hrs of the first dose of hydrocortisone.

MEASUREMENTS AND MAIN RESULTS

Forty-seven percent of patients died. Twenty-two percent of patients met the diagnostic criteria of adrenal insufficiency by the low-dose test and 8% by the high-dose test. However, 61% of patients met the criteria of adrenal insufficiency when we used a baseline cortisol concentration of <25 microg/dL. Twenty-two patients (37%) were steroid responsive; the baseline serum cortisol was 14.1 +/- 5.2 microg/dL in the steroid-responsive patients compared with 33.3 +/- 18 microg/dL in the steroid-nonresponsive patients (p <.0001). Ninety-five percent of steroid-responsive patients had a baseline cortisol concentration <25 microg/dL. Fifty-four percent of steroid responders had a diagnostic low-dose test and 22% a diagnostic high-dose test. Receiver operating characteristic curve analysis revealed that a stress cortisol concentration of 23.7 microg/dL was the most accurate diagnostic threshold for determination of the hemodynamic response to glucocorticoid therapy.

CONCLUSIONS

Adrenal insufficiency is common in patients with septic shock, the incidence depending largely on the diagnostic test and criteria used to make the diagnosis. There is clearly no absolute serum cortisol concentration that distinguishes an adequate from an insufficient adrenal response. However, we believe that a random cortisol concentration of <25 microg/dL in a highly stressed patient is a useful diagnostic threshold for the diagnosis of adrenal insufficiency.