Management of Severe Sepsis: Integration of Multiple Pharmacologic Interventions

Immunoneutralization of the aminoprocalcitonin peptide of procalcitonin protects rats from lethal endotoxaemia: neuroendocrine and systemic studies

Severe sepsis and septic shock are an important cause of mortality and morbidity. These illnesses can be triggered by the bacterial endotoxin LPS (lipopolysaccharide) and pro-inflammatory cytokines, particularly TNF-α (tumour necrosis factor-α) and IL (interleukin)-1β. Severity and mortality of sepsis have also been associated with high concentrations of N-PCT (aminoprocalcitonin), a 57-amino-acid neuroendocrine peptide derived from ProCT (procalcitonin). Previous studies in a lethal model of porcine polymicrobial sepsis have revealed that immunoneutralization with IgG that is reactive to porcine N-PCT significantly improves short-term survival. To explore further the pathophysiological role of N-PCT in sepsis, we developed an antibody raised against a highly conserved amino acid sequence of human N-PCT [N-PCT-(44-57)]. This sequence differs by only one amino acid from rat N-PCT. First, we demonstrated the specificity of this antibody in a well-proven model of anorexia induced in rats by central administration of human N-PCT-(1-57). Next we explored further the therapeutic potential of anti-N-PCT-(44-57) in a rat model of lethal endotoxaemia and determined how this immunoneutralization affected LPS-induced lethality and cytokine production. We show that this specific antibody inhibited the LPS-induced early release of TNF-α and IL-1β and increased survival, even if treatment began after the cytokine response had occurred. In addition, anti-N-PCT-(44-57) may increase long-term survival in LPS-treated rats by up-regulating the late production of counter-regulatory anti-inflammatory mediators such as ACTH (adrenocorticotropic hormone) and IL-10. In conclusion, these results support N-PCT as a pro-inflammatory factor in both the early and the late stages of lethal endotoxaemia, and suggest anti-N-PCT as a candidate for septic shock therapy.

Addition of Vasopressin to Norepinephrine as Independent Predictor of Mortality in Patients with Refractory Septic Shock: An Observational Study

OBJECTIVE

To identify predictors of 28-day mortality among patients with refractory septic shock treated with norepinephrine with or without vasopressin.

DESIGN

Prospective observational cohort study.

SETTING

A 1,200-bed academic medical center.

PATIENTS

One hundred thirty-seven patients with septic shock treated with norepinephrine with or without vasopressin.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The 28-day mortality rate was 37.2% (n = 51). By multivariate analysis, significant predictors of death were norepinephrine plus vasopressin administration (adjusted odds ratio [AOR], 13.96; 95% confidence interval [CI] 6.47, 30.08; p = 0.001), lack of goal-directed fluid administration during initial resuscitation (AOR 15.82; 95% CI 6.16, 40.61; p = 0.003), inappropriate initial antimicrobial therapy (AOR 8.95; 95% CI 2.93, 27.33; p = 0.05), and higher Acute Physiology and Chronic Health Evaluation (APACHE) II score (AOR 1.14; 95% CI 1.07, 1.21; p = 0.033). Patients who received norepinephrine plus vasopressin (n = 68) had a significantly higher mortality rate than patients managed with norepinephrine alone (n = 69) 28 days after the initiation of vasopressors (54.4% vs. 20.3%; p < 0.001). This finding was confirmed in patients matched optimally across treatment groups.

CONCLUSIONS

Our study found an association between the use of norepinephrine plus vasopressin and 28-day mortality in refractory septic shock. In view of its known mechanism of action, vasopressin contributed to this excess mortality. Further recommendations regarding the use of vasopressin await the results of large randomized trials evaluating its efficacy and safety for septic shock.

Protective effects of heme-oxygenase expression against endotoxic shock: inhibition of tumor necrosis factor-alpha and augmentation of interleukin-10

BACKGROUND

Heme-oxygenase (HO)-1 acts as an inducible defense against oxidative stress and could play an important role in inflammation models, providing protection against oxidative stress and systemic inflammatory response. The objective of this study was to improve the role of HO-1 on systemic inflammatory response in an endotoxic shock model.

METHODS

Five groups of animals were used: control group; lipopolysaccharide (LPS) group, animals received LPS 5 mg/kg; hemin + LPS group, animals received pretreatment with hemin, used to induce HO-1 expression; Zn-PP group, animals received Zn-PP, a specific inhibitor of HO-1 activity and hemin group. At the end of the experiment, tissue and blood samples were isolated for the measurement of HO-1 mRNA expression, biochemical measurements, and cytokine measurements.

RESULTS

HO-1 messenger RNA expression and protein were induced to a larger extent in LPS group in distal organs. Hemin pretreatment induced a significant decrease oxidative stress and tumor necrosis factor-alpha plasma levels with a significant increase of interleukin-10 plasma levels. Pulmonary injury was markedly limited after hemin. Onset of lethality in LPS group occurred at H6, and was delayed until H10 with hemin. Inhibition of HO-1 activity by Zn-PP administration abolished the beneficial effect of hemin-pretreatment.

CONCLUSIONS

Early HO-1 expression may modulate systemic inflammatory response and limit end-organ injury in endotoxic shock model.

Before–after study of a standardized hospital order set for the management of septic shock*

OBJECTIVE

To evaluate a standardized hospital order set for the management of septic shock in the emergency department.

DESIGN

Before-after study design with prospective consecutive data collection.

SETTING

Emergency department of a 1,200-bed academic medical center.

PATIENTS

A total of 120 patients with septic shock.

INTERVENTIONS

Implementation of a standardized hospital order set for the management of septic shock.

MEASUREMENTS AND MAIN RESULTS

A total of 120 consecutive patients with septic shock were identified. Sixty patients (50.0%) were managed before the implementation of the standardized order set, constituting the before group, and 60 (50.0%) were evaluated after the implementation of the standardized order set, making up the after group. Demographic variables and severity of illness measured by the Acute Physiology and Chronic Health Evaluation II were similar for both groups. Patients in the after group received statistically more intravenous fluids while in the emergency department (2825 +/- 1624 mL vs. 3789 +/- 1730 mL, p = .002), were more likely to receive intravenous fluids of >20 mL/kg body weight before vasopressor administration (58.3% vs. 88.3%, p < .001), and were more likely to be treated with an appropriate initial antimicrobial regimen (71.7% vs. 86.7%, p = .043) compared with patients in the before group. Patients in the after group were less likely to require vasopressor administration at the time of transfer to the intensive care unit (100.0% vs. 71.7%, p < .001), had a shorter hospital length of stay (12.1 +/- 9.2 days vs. 8.9 +/- 7.2 days, p = .038), and a lower risk for 28-day mortality (48.3% vs. 30.0%, p = .040).

CONCLUSIONS

Our study found that the implementation of a standardized order set for the management of septic shock in the emergency department was associated with statistically more rigorous fluid resuscitation of patients, greater administration of appropriate initial antibiotic treatment, and a lower 28-day mortality. These data suggest that the use of standardized order sets for the management of septic shock should be routinely employed.

Endogenous and exogenous glucocorticoids in experimental enterococcal infection

The potentially protective role of the host adrenal-glucocorticoid response to enterococcal infection was evaluated in an experimental model in which mice were infected intraperitoneally with two distinct Enterococcus faecalis strains (K9 and CP-1). We demonstrated that corticosterone levels in serum and peritoneal-lavage fluid were elevated within 1 hour of infection with either E. faecalis strain. We also demonstrated that adrenalectomized mice generated a more robust localized peritoneal tumor necrosis factor alpha (TNF-alpha) response to both E. faecalis strains than did sham-adrenalectomized mice but that neither E. faecalis strain induced a systemic TNF-alpha response. Further, peritoneal TNF-alpha production in adrenalectomized mice infected with either E. faecalis K9 or CP-1 was suppressed by prior treatment with an exogenous glucocorticoid (dexamethasone). The potential clinical significance of these results was suggested by our findings that adrenalectomy markedly increased susceptibility (a>100-fold decrease in the 50% lethal dose) to lethal infections with E. faecalis CP-1 and that prior dexamethasone treatment partially compensated for adrenalectomy. In marked contrast to these findings, however, adrenalectomy did not substantially increase susceptibility to lethal E. faecalis K9 infection. Further, preinfection with E. faecalis CP-1 1 hour before infection with E. faecalis K9 did not protect mice from lethal E. faecalis K9 infections. Collectively, these studies indicate that the host can generate a glucocorticoid response to E. faecalis infection that suppresses TNF-alpha production. Further, this glucocorticoid response can protect the host from potentially lethal E. faecalis infections, but different strains show heterogeneity with respect to the extent of protection afforded by the adrenal-glucocorticoid response.

Predictors of hospital mortality for patients with severe sepsis treated with Drotrecogin alfa (activated)

STUDY OBJECTIVE

To identify predictors of hospital mortality among patients with severe sepsis who were treated with drotrecogin alfa (activated).

DESIGN

Prospective observational cohort study.

SETTING

A 1400-bed academic medical center.

PATIENTS

One hundred two patients treated with drotrecogin alfa (activated) for severe sepsis.

MEASUREMENTS AND MAIN RESULTS

To identify potential risk factors for hospital mortality, the main outcome evaluated, all patients who received drotrecogin alfa (activated) were segregated according to hospital survival. The following characteristics were recorded: age, sex, weight, surgical or nonsurgical, Acute Physiology and Chronic Health Evaluation (APACHE) II score, number of acquired organ-system derangements, mechanical ventilation, use of vasopressors or dobutamine, patient location 24 hours before receiving drotrecogin alfa (activated), source of infection, microbiologically positive culture, and other process-of-care variables. Of the 102 patients, 43 (42.2%) died during their hospitalization. Potential predictors of hospital mortality identified by univariate analysis included greater APACHE II scores, administration of vasopressin or dobutamine, number of acquired organ-system derangements, time to treatment with drotrecogin alfa (activated), intravenous fluid administered before receiving vasopressors or drotrecogin alfa (activated), number of red blood cell transfusions, and administration of inappropriate initial antimicrobial treatment. Multivariate analysis revealed that vasopressin administration (odds ratio [OR] 3.72, 95% confidence interval [CI] 1.95-7.10), number of acquired organ-system derangements (OR 2.30, 95% CI 1.59-3.31), and administration of inappropriate initial antimicrobial treatment (OR 15.5, 95% CI 6.78-35.6) were independently associated with hospital mortality.

CONCLUSION

Number of acquired organ-system derangements, vasopressin administration, and treatment with an inappropriate initial antimicrobial regimen are independently associated with an increased risk of hospital mortality among patients treated with drotrecogin alfa (activated) for severe sepsis. These findings suggest that other specific medical interventions may increase survival in this patient population.

Management of severe sepsis and septic shock

PURPOSE OF REVIEW

Severe sepsis and septic shock are common and deadly conditions for which the epidemiology, pathogenesis, and management continue to evolve. Recent publications (2003 and early 2004) have been systematically reviewed for important new original research and scholarly reviews, with an emphasis on clinical advances in adults.

RECENT FINDINGS

Important new epidemiologic studies establish the increasing frequency (nearly 9% per year) and falling mortality rates associated with sepsis. Sepsis definitions were reviewed by a group of experts, and the principal features of the 1991 consensus conference definitions were supported, with a new framework for evaluation of sepsis proposed. New research and thoughtful reviews continue to elucidate the pathogenesis of sepsis, with emphasis on innate immunity and time-based changes in immune status, varying from hyperreactive immunity and inflammation to immune depression with enhanced risk for nosocomial infections. A comprehensive evidence-based approach to the management of severe sepsis is presented in an important document developed by representatives from many critical care and infectious disease societies. Management includes early targeted resuscitation, broad empiric antibiotic coverage and source control, effective shock evaluation and treatment, adjuvant therapy with recombinant human activated protein C and moderate-dose hydrocortisone in selected patients, and comprehensive supportive care. Recently published multicenter clinical trials for novel agents have been disappointing, particularly for a nitric oxide synthase inhibitor that effectively supported blood pressure but increased mortality.

SUMMARY

The works reviewed reflect the advances in the care of patients with sepsis.