Corticosteroids in sepsis: from bench to bedside?

Corticosteroid replacement in critically ill patients

This review addresses the use of corticosteroid replacement in critically ill patients. Low-dose corticosteroid replacement for critically ill patients with septic shock has been shown to reduce the duration of vasopressor-dependent shock, to shorten ICU length of stay, and, in recent trials, to reduce mortality. Numerous questions remain to be fully answered about patient selection, corticotropin-stimulation testing methods, and interpretation of results.

Adrenal insufficiency in patients with cirrhosis, severe sepsis and septic shock

Patients with cirrhosis are susceptible to bacterial infection, which can result in circulatory dysfunction, renal failure, hepatic encephalopathy, and a decreased survival rate. Severe sepsis is frequently associated with adrenal insufficiency, which may lead to hemodynamic instability and a poor prognosis. We evaluated adrenal function using short corticotropin stimulation test (SST) in 101 critically ill patients with cirrhosis and severe sepsis. Adrenal insufficiency occurred in 51.48% of patients. The patients with adrenal insufficiency had a higher hospital mortality rate when compared with those with normal adrenal function (80.76% vs. 36.7%, P < .001). The cumulative rates of survival at 90 days were 15.3% and 63.2% for the adrenal insufficiency and normal adrenal function groups, respectively (P < .0001). The hospital survivors had a higher cortisol response to corticotropin (16.2 +/- 8.0 vs. 8.5 +/- 5.9 microg/dL, P < .001). The cortisol response to corticotropin was inversely correlated with various disease severity, Model for End-Stage Liver Disease, and Child-Pugh scores. Acute physiology, age, chronic health evaluation III score, and cortisol increment were independent factors to predict hospital mortality. Mean arterial pressure on the day of SST was lower in patients with adrenal insufficiency (60 +/- 14 vs. 74.5 +/- 13 mm Hg, P < .001), and a higher proportion of these patients required vasopressors (73% vs. 24.48%, P < .001). Mean arterial pressure, serum bilirubin, vasopressor dependency, and bacteremia were independent factors that predicted adrenal insufficiency. In conclusion, adrenal insufficiency is common in critically ill patients with cirrhosis and severe sepsis. It is related to functional liver reserve and disease severity and is associated with hemodynamic instability, renal dysfunction, and increased mortality.

Relative Adrenal Failure in the ICU: An Identifiable Problem Requiring Treatment

Critically ill patients at some stage may develop adrenal insufficiency (AI). This article reviews the mechanisms, diagnosis criteria, consequences, and treatment of AI in various ICU conditions. Glucocorticoid insufficiency may be related to a decrease in glucocorticoid synthesis (ie, adrenal insufficiency) or to a reduced delivery of glucocorticoid to target tissues and cells. Diagnosis relies on clinical suspicion and ACTH test results. The length of cortisol replacement therapy should be at least 7 days and the adjunction of fludrocortisone is recommended.

Incidence of adrenal insufficiency after severe traumatic brain injury varies according to definition used: clinical implications

BACKGROUND

Adrenal insufficiency impacts on the haemodynamic management of patients in intensive care. Very little is known about the incidence of adrenal insufficiency in the first 10 days after traumatic brain injury.

METHODS

We retrospectively reviewed the charts of 113 traumatic brain injury patients within 10 days of their injury. They all had a high-dose corticotropin stimulation test performed because of haemodynamic instability. Blood cortisol concentrations were measured at baseline, 30 and 60 min after the administration of high-dose corticotropin. The incidence of adrenal insufficiency was determined according to various definitions used in the literature.

RESULTS

The baseline cortisol concentration was <414 nmol litre(-1) (15 microg dl(-1)) in 78% of patients and <690 nmol litre(-1) (25 microg dl(-1)) in all patients. The cortisol concentration did not rise above 500 nmol litre(-1) (18 microg dl(-1)) at 30 and 60 min in 49 and 22% of patients, respectively. The cortisol concentration did not rise by 250 nmol litre(-1) (9 microg dl(-1)) at 30 and 60 min in 48 and 25% of patients respectively. Primary adrenal insufficiency defined by an abnormal baseline cortisol concentration and an abnormal response to the high-dose corticotropin stimulation test was present in 13-28% of patients according to the cut-off values used.

CONCLUSIONS

The incidence of adrenal insufficiency varies from 25 to 100% in the first 10 days after traumatic brain injury. The range of incidences reported illustrates the need for standardization of the definition of adrenal insufficiency. This has a direct impact on treatment. Sampling at 60 min after the high-dose corticotropin stimulation test seems to correlate better with the maximum secreting capacity of the adrenal glands.

Cell adhesion molecules as a marker reflecting the reduction of endothelial activation induced by glucocorticoids

In vitro, steroids down-regulate the expression of cell adhesion molecules (CAMs) in endothelial cells stimulated by lipopolysaccharide. Low-dose hydrocortisone is a new treatment of patients with septic shock, a state that is characterized by an endothelial injury. The aim of the present study was to investigate whether the plasma levels of soluble CAMs, reflecting in vivo endothelial activation, could be modulated in patients with septic shock treated by hydrocortisone. This was a prospective and observational study conducted in the intensive care unit at a university hospital. The subjects included 40 patients with septic shock (American College of Chest Physicians Consensus Conference/Society of Critical Care Medicine definition); 45 healthy blood donors served as controls. The patients receiving the standard care ("reference group") during the first 6 months were compared with the patients receiving the hydrocortisone therapy ("hydrocortisone group") for the next 6 months. Measurements of sCAMs were performed on days 1 and 3 of the disease. On day 1, sE-selectin, sP-selectin, sVCAM-1, and sICAM-1 were significantly elevated in patients with septic shock compared with healthy donors. sE-selectin levels significantly decreased between days 1 and 3 in the "hydrocortisone group," whereas there was no significant change in the "reference group". Surprisingly, sICAM-1 levels significantly increased between days 1 and 3 only in patients treated by hydrocortisone. No significant changes were observed for sP-selectin and sVCAM-1 levels in the two groups. In patients with septic shock, glucocorticoids differently affected the pattern of evolution of sCAMs, with sE-selectin being decreased and sICAM-1 being increased. Expression of sP-selectin and sVCAM-1 was not affected.

Pathophysiology of Mifepristone-Induced Septic Shock Due toClostridium sordellii

OBJECTIVE:

To explain the role of mifepristone in medical abortions that results in fulminant and lethal septic shock due to Clostridium sordellii.

DATA SOURCES:

MEDLINE, PubMed, and Google Scholar databases were searched (1984–March 2005%). Key search terms were mifepristone, RU38486, RU486, Mifeprex, medical abortion, septic shock, innate immune system, cytokines, and Clostridium sordellii.

STUDY SELECTION AND DATA EXTRACTION:

All articles identified from the data sources were evaluated and all information deemed relevant was included for the information related to the development of the understanding of the pathophysiology of mifepristone-induced septic shock due to C. sordellii.

DATA SYNTHESIS:

The mechanisms of action of mifepristone were incorporated into the pathophysiology of septic shock due to C. sordellii. Mifepristone, by blocking both progesterone and glucocorticoid receptors, interferes with the controlled release and functioning of cortisol and cytokines. Failure of physiologically controlled cortisol and cytokine responses results in an impaired innate immune system that results in disintegration of the body's defense system necessary to prevent the endometrial spread of C. sordellii infection. The abnormal cortisol and cytokine responses due to mifepristone coupled to the release of potent exotoxins and an endotoxin from C. sordellii are the major contributors to the rapid development of lethal septic shock.

CONCLUSIONS:

Theoretically, it appears that the mechanisms of mifepristone action favor the development of infection that leads to septic shock and intensifies the actions of multiple inflammatory cytokines, resulting in fulminant, lethal septic shock.

Circulating levels of macrophage migration inhibitory factor are associated with mild pulmonary dysfunction after cardiopulmonary bypass

Macrophage migration inhibitory factor (MIF) is a central mediator of inflammatory response and acute lung injury that is secreted in response to corticosteroids. A rise in systemic MIF levels was described after cardiac surgery in steroid-treated patients. This study aimed to investigate the circulating levels of MIF and the possible relationship of this cytokine to pulmonary dysfunction after cardiopulmonary bypass (CPB). We included 74 patients without previous organ dysfunction undergoing elective coronary artery bypass surgery (CABS). The same team performed all CABS via a standard technique adding methylprednisolone (15 mg/kg) to the CPB priming solution (Group MP, n = 37). In the remaining patients (Group NS, n = 37), methylprednisolone was withdrawn from the CPB priming. MIF, C-reactive protein (CRP), and total C3 were assayed in peripheral blood sampled immediately before anesthesia induction and 3, 6, and 24 h post-CPB. Preoperative risk scores and peri- and postoperative variables were documented. Postoperative kinetics of MIF and C3 were similar for both groups. Levels of CRP 24 h post-CPB were higher in Group MP (P = 0.003). Higher MIF levels were detected 6 h post-CPB, and returned to preoperative levels 24 h after CPB. MIF levels 6 h post-CPB were inversely related to the postoperative PaO2/FiO2 ratio (P = 0.0021) and were directly related to the duration of mechanical ventilation (P = 0.014). Perioperative use of methylprednisolone did not modify the MIF response to CPB, but it was related to an enhanced acute phase response. Higher circulating MIF levels 6 h post-CPB were associated with worse postoperative pulmonary short-course outcome.

Should we use etomidate as an induction agent for endotracheal intubation in patients with septic shock?: a critical appraisal

Etomidate is commonly used for the facilitation of endotracheal intubation. While etomidate possesses multiple qualities that are beneficial in hemodynamically unstable patients who require a sedative or amnestic, its potential to negatively impact corticosteroid production is well-documented. Given the frequency of relative adrenal insufficiency observed in the critically ill and the increasing use of corticosteroids in patients with septic shock, an appraisal of the status of etomidate as an induction agent in patients with evolving or established septic shock is indicated. A review of the relevant literature suggests that its use in this setting may be harmful. It is proposed that, pending the performance of a randomized, controlled clinical trial, considerable caution should accompany its administration in patients with evolving or established septic shock. The potential role for concomitant empiric steroid replacement and the comparability of alternative induction regimens are also discussed.

Expression of osteoactivin in rat and human liver and isolated rat liver cells

BACKGROUND/AIMS

The transmembrane glycoprotein osteoactivin is expressed in osteoblasts, dendritic cells and tumor cells. It is suggested to influence osteoblast maturation, cell adhesion and migration. We studied osteoactivin expression within the liver.

METHODS

Expression of osteoactivin was analysed by RT-PCR, Northern blotting, in situ hybridisation (ISH) and immunohistochemistry (IHC) comparing normal and acutely injured rat liver [induced by carbon tetrachloride (CCl(4)) administration], liver cell populations, and normal or diseased human liver.

RESULTS

By ISH osteoactivin expression was detected in sinusoid-lining cells found by IHC to be positive for the common mononuclear phagocyte marker antibody anti-CD68. While total liver contained only traces, isolated Kupffer cells expressed abundant amounts of osteoactivin mRNA further increasing during culture. In acutely injured rat liver osteoactivin expression was strongly increased reaching maximum of expression 48h after CCl(4). By ISH osteoactivin expression was localised in pericentral inflammatory cells and sinusoid-lining cells again anti-CD68 positive. Dexamethasone and lipopolysaccharide decreased osteoactivin expression in cultured mononuclear phagocytes of normal as well as of acutely injured liver. In human liver osteoactivin was increased in fulminant hepatitis and paracetamol intoxication.

CONCLUSIONS

Osteoactivin is expressed at high levels in normal and inflammatory liver macrophages suggesting a significant role in acute liver injury.

Absolute and relative adrenal insufficiency in children with septic shock*

OBJECTIVE

Corticosteroid replacement improves outcome in adults with relative adrenal insufficiency and catecholamine-resistant septic shock. We evaluated the relationship of absolute and relative adrenal insufficiency to catecholamine-resistant septic shock in children.

DESIGN

Prospective cohort study.

SETTING

University hospital pediatric intensive care unit in Brazil.

PATIENTS

Fifty-seven children with septic shock. Children with HIV infection, those with a history of adrenal insufficiency, and those submitted to any steroid therapy or etomidate within the week before diagnosis of septic shock were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A short corticotropin test (250 microg) was performed, and cortisol levels were measured at baseline and 30 and 60 mins posttest. Adrenal insufficiency was defined by a response < or =9 microg/dL. Absolute adrenal insufficiency was further defined by a baseline cortisol <20 microg/dL and relative adrenal insufficiency by a baseline cortisol >20 microg/dL. Absolute adrenal insufficiency was observed in 18% of children, all of whom had catecholamine-resistant shock. Relative adrenal insufficiency was observed in 26% of children, of whom 80% had catecholamine-resistant and 20% had dopamine/dobutamine-responsive shock. All children with fluid-responsive shock had a cortisol response >9 microg/dL. Children with adrenal insufficiency had an increased risk of catecholamine-resistant shock (relative risk, 1.88; 95% confidence interval, 1.26-2.79). However, mortality was independently predicted by chronic illness or multiple organ failure (p < .05), not adrenal insufficiency.

CONCLUSIONS

Absolute and relative adrenal insufficiency is common in children with catecholamine-resistant shock and absent in children with fluid-responsive shock. Studies are warranted to determine whether corticosteroid therapy has a survival benefit in children with relative adrenal insufficiency and catecholamine-resistant septic shock.

Therapie des Organversagens bei prim�r extrakardialen Erkrankungen

There are a number of primary extracardiac circulatory disorders leading to organ dysfunction, multi-organ dysfunction syndrome and finally to multi-organ-failure. The origin of this hemodynamic disturbances are potentially different forms of circulatory shock (septic, hypovolemic, anaphylactic or neurogenic shock) and the systemic inflammatory reaction syndrome (SIRS). The primary aim of therapy is the removal of the underlying causes and the restoration of adequate tissue perfusion by using fluids, vasopressors and inotropics. The supportive treatment of the individual organ dysfunction is - at present - unequally efficient.

Cortisol levels and adrenal reserve after successful cardiac arrest resuscitation

The postresuscitation phase after out-of-hospital circulatory arrest shares similarities with severe sepsis. Corticosteroid replacement is beneficial in patients with septic shock and adrenal dysfunction. The goal of this study was to assess baseline cortisol and adrenal reserve of out-of-hospital circulatory arrest patients after recovery of spontaneous circulation. Thirty-three consecutive patients successfully resuscitated after cardiac arrest were prospectively included between March 2002 and June 2003. A serum cortisol assay and a corticotropin test (250 microg i.v.) were done 6 to 36 h after circulatory arrest. A cortisol increase smaller than 9 microg/dL after corticotropin (nonresponders) defined adrenal reserve insufficiency. Response status was compared in the three outcome groups: survival with full neurologic recovery (n = 4), early death from refractory shock (n = 10), or later death from neurologic dysfunction (n = 19). Patients who died of early refractory shock had lower baseline cortisol levels than patients who died of neurologic dysfunction (27 microg/dL [15-47] vs. 52 microg/dL [28-73], respectively; P < 0.01), suggesting an inadequate adrenal response to severe systemic inflammation. Corticotropin response status was not associated with standard severity markers and seemed uninfluenced by therapeutic hypothermia. In conclusion, patients who die of early refractory shock after cardiopulmonary resuscitation may have an inadequate adrenal response to the stress associated with this condition. Thresholds for cortisol levels at baseline and after corticotropin need to be determined in this clinical setting.

Corticosteroids for severe sepsis and septic shock: a systematic review and meta-analysis

OBJECTIVE

To assess the effects of corticosteroids on mortality in patients with severe sepsis and septic shock.

DATA SOURCES

Randomised and quasi-randomised trials of corticosteroids versus placebo (or supportive treatment alone) retrieved from the Cochrane infectious diseases group's trials register, the Cochrane central register of controlled trials, Medline, Embase, and LILACS.

REVIEW METHOD

Two pairs of reviewers agreed on eligibility of trials. One reviewer entered data on to the computer and four reviewers checked them. We obtained some missing data from authors of trials and assessed methodological quality of trials.

RESULTS

16/23 trials (n = 2063) were selected. Corticosteroids did not change 28 day mortality (15 trials, n = 2022; relative risk 0.92, 95% confidence interval 0.75 to 1.14) or hospital mortality (13 trials, n = 1418; 0.89, 0.71 to 1.11). There was significant heterogeneity. Subgroup analysis on long courses (> or = 5 days) with low dose (< or = 300 mg hydrocortisone or equivalent) corticosteroids showed no more heterogeneity. The relative risk for mortality was 0.80 at 28 days (five trials, n = 465; 0.67 to 0.95) and 0.83 at hospital discharge (five trials, n = 465, 0.71 to 0.97). Use of corticosteroids reduced mortality in intensive care units (four trials, n = 425, 0.83, 0.70 to 0.97), increased shock reversal at 7 days (four trials, n = 425; 1.60, 1.27 to 2.03) and 28 days (four trials, n = 425, 1.26, 1.04 to 1.52) without inducing side effects.

CONCLUSIONS

For all trials, regardless of duration of treatment and dose, use of corticosteroids did not significantly affect mortality. With long courses of low doses of corticosteroids, however, mortality at 28 days and hospital morality was reduced.

Science review: extracellular acidosis and the immune response: clinical and physiologic implications

Metabolic acidosis is among the most common abnormalities seen in patients suffering from critical illness. Its etiologies are multiple and treatment of the underlying condition is the mainstay of therapy. However, growing evidence suggests that acidosis itself has profound effects on the host, particularly in the area of immune function. Given the central importance of immune function to the outcome of critical illness, there is renewed interest in elucidating the effects of this all too common condition on the immune response. In this review we concentrate on the effects of extracellular acids on production and release of inflammatory mediators, and we demonstrate that different acids produce different effects despite similar extracellular pH. Finally, we discuss potential clinical implications.

Science review: mechanisms of impaired adrenal function in sepsis and molecular actions of glucocorticoids

This review describes current knowledge on the mechanisms that underlie glucocorticoid insufficiency in sepsis and the molecular action of glucocorticoids. In patients with severe sepsis, numerous factors predispose to glucocorticoid insufficiency, including drugs, coagulation disorders and inflammatory mediators. These factors may compromise the hypothalamic–pituitary axis (i.e. secondary adrenal insufficiency) or the adrenal glands (i.e. primary adrenal failure), or may impair glucocorticoid access to target cells (i.e. peripheral tissue resistance). Irreversible anatomical damages to the hypothalamus, pituitary, or adrenal glands rarely occur. Conversely, transient functional impairment in hormone synthesis may be a common complication of severe sepsis. Glucocorticoids interact with a specific cytosolic glucocorticoid receptor, which undergoes conformational changes, sheds heat shock proteins and translocates to the nucleus. Glucocorticoids may also interact with membrane binding sites at the surface of the cells. The molecular action of glucocorticoids results in genomic and nongenomic effects. Direct and indirect transcriptional and post-transcriptional effects related to the cytosolic glucocorticoid receptor account for the genomic effects. Nongenomic effects are probably subsequent to cytosolic interaction between the glucocorticoid receptor and proteins, or to interaction between glucocorticoids and specific membrane binding sites.

Surviving Sepsis Campaign guidelines for management of severe sepsis and septic shock

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for 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

We used a modified Delphi methodology 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 were provided to contrast adult and pediatric management.

RESULTS

Key recommendations, listed by category and not by hierarchy, include early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition; appropriate diagnostic studies to ascertain causative organisms before starting antibiotics; early administration of broad-spectrum antibiotic therapy; reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate; a usual 7-10 days of antibiotic therapy guided by clinical response; source control with attention to the method that balances risks and benefits; equivalence of crystalloid and colloid resuscitation; aggressive fluid challenge to restore mean circulating filling pressure; vasopressor preference for norepinephrine and dopamine; cautious use of vasopressin pending further studies; avoiding low-dose dopamine administration for renal protection; consideration of dobutamine inotropic therapy in some clinical situations; avoidance of supranormal oxygen delivery as a goal of therapy; stress-dose steroid therapy for septic shock; use of recombinant activated protein C in patients with severe sepsis and high risk for death; with resolution of tissue hypoperfusion and in the absence of coronary artery disease or acute hemorrhage, targeting a hemoglobin of 7-9 g/dL; appropriate use of fresh frozen plasma and platelets; a low tidal volume and limitation of inspiratory plateau pressure strategy for acute lung injury and acute respiratory distress syndrome; application of a minimal amount of positive end-expiratory pressure in acute lung injury/acute respiratory distress syndrome; a semirecumbent bed position unless contraindicated; protocols for weaning and sedation/analgesia, using either intermittent bolus sedation or continuous infusion sedation with daily interruptions/lightening; avoidance of neuromuscular blockers, if at all possible; maintenance of blood glucose <150 mg/dL after initial stabilization; equivalence of continuous veno-veno hemofiltration and intermittent hemodialysis; lack of utility of bicarbonate use for pH > or =7.15; use of deep vein thrombosis/stress ulcer prophylaxis; and consideration of limitation of support where appropriate. Pediatric considerations included a more likely need for intubation due to low functional residual capacity; more difficult intravenous access; fluid resuscitation based on weight with 40-60 mL/kg or higher needed; decreased cardiac output and increased systemic vascular resistance as the most common hemodynamic profile; greater use of physical examination therapeutic end points; unsettled issue of high-dose steroids for therapy of septic shock; and greater risk of hypoglycemia with aggressive glucose control.

CONCLUSION

Evidence-based recommendations can be made regarding many aspects of the acute management of sepsis and septic shock that are hoped to translate into improved outcomes for the critically ill patient. The impact of these guidelines will be formally tested and guidelines updated annually and even more rapidly as some important new knowledge becomes as available.

Surviving Sepsis Campaign guidelines for management of severe sepsis and septic shock

OBJECTIVE

To develop management guidelines for 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. The modified Delphi methodology used for grading recommendations built upon a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along 5 levels to create recommendation grades from A-E, with A being the highest grade. Pediatric considerations were provided to contrast adult and pediatric management.

PARTICIPANTS

Participants included 44 critical care and infectious disease experts representing 11 international organizations.

RESULTS

A total of 46 recommendations plus pediatric management considerations.

CONCLUSIONS

Evidence-based recommendations can be made regarding many aspects of the acute management of sepsis and septic shock that will hopefully translate into improved outcomes for the critically ill patient. The impact of these guidelines will be formally tested and guidelines updated annually, and even more rapidly when some important new knowledge becomes available.