Pediatric sepsis: challenges and adjunctive therapies

Impact of CytoSorb and CKRT on hemodynamics in pediatric patients with septic shock: the PedCyto study

Background

There is a lack of data to support the use of hemoadsorption in pediatric septic shock. The aim of our study was to assess the effectiveness and safety of CytoSorb therapy in this setting.

Methods

Phase II interventional single arm pilot study in which 17 consecutive children admitted with septic shock who required continuous kidney replacement therapy (CKRT) and weighed ≥10 kg were included. A CytoSorb (CytoSorbents Inc, New Jersey, USA) hemoadsorption cartridge was added to the CKRT every 24 h for a maximum of 96 h. A control group of 13 children with septic shock treated with CKRT but not hemoadsorption at Children's Hospital Bambino Gesù and enrolled in the EuroAKId register was selected as an historical cohort. The primary outcome of the study was a reduction in vasopressor or inotrope dose of >50% from baseline by the end of CytoSorb therapy. Secondary outcomes included hemodynamic and biological changes, changes in severity scores, and 28-day mortality.

Results

There were significant decreases in the Vasoactive Inotropic Score (VIS) and the Pediatric Logistic Organ Dysfunction 2 (PELOD-2) score at 72 and 96 h from the start of the CytoSorb therapy compared to baseline; the reductions were larger in the hemoadsorption group than in the control group (historical cohort). 28-day mortality was lower, although not significantly, in the hemoadsorption group when compared to the control group (5/17 [29%] vs. 8/13 [61%] OR 0.26 [95% CI: 0.05-1.2]; p = 0.08).

Conclusions

CytoSorb therapy may have some benefits in pediatric patients with septic shock. Future larger randomized trials are needed in this setting.

Clinical Trial Registration

https://clinicaltrials.gov/ct2/show/NCT05658588, identifier (Clinicaltrials.gov NCT05658588).

Outcomes of Pediatric Patients with Sepsis Managed on Extracorporeal Membrane Oxygenation: An Analysis of the Extracorporeal Life Support Organization Registry

Extracorporeal membrane oxygenation (ECMO) support is increasingly used for refractory septic shock. There is a lack of data on the outcomes of children requiring ECMO support for refractory septic shock. Our study objective was to describe the variables associated with survival, risk factors for mortality, and outcomes of children requiring ECMO support for refractory shock. This was retrospective registry study of 340 international centers contributing data to the ELSO Registry, analyzing children <18 years who received ECMO with septic shock, severe sepsis, sepsis, systemic inflammatory response syndrome, toxic shock syndrome, shock associated with infection, and septicemia from any organism from 1990 to 2015. Outcomes were analyzed by categorizing the data into survivors and nonsurvivors. Logistic regression models were used to describe the association of dependent variable and multiple independent variables. A total of 1,928 patients were identified who met the inclusion criteria. In total, 744 (38.5%) of the cohort survived. Survivors in this cohort tend to have a longer duration of ECMO (230 vs. 201 hours, p = 0.005) and shorter time from intubation to ECMO cannulation (87 vs. 116 hours, p = 0.0033) when compared to nonsurvivors. Survivors were also noted to have higher pH, higher serum bicarbonate, higher saturations, and higher systolic, diastolic, and mean arterial pressures compared to nonsurvivors. These results suggest that early initiation of ECMO therapy for refractory sepsis is associated with better patient outcomes. ECMO is unlikely to recover patients once circulatory and metabolic collapse has developed.

Thrombocytopenia and Bloodstream Infection: Incidence and Implication on Length of Stay in the Pediatric Intensive Care Unit

The incidence and prognosis of thrombocytopenia in critically ill patients with bloodstream infection (BSI) is not well delineated in the pediatric intensive care unit (PICU) setting. We assessed these variables in our PICU and sought to determine whether thrombocytopenia could serve as a prognostic marker for length of stay (LOS). The study was conducted at the medical PICU of a university hospital, on all critically ill pediatric patients consecutively admitted during a 3-year period. Patient surveillance and data collection have been used to identify the risk factors during the study period. The main outcomes were BSI incidence and implication on morbidity and LOS. Data from 2,349 PICU patients was analyzed. The overall incidence of BSI was 3.9% (93/2,349). Overall, 85 of 93 patients (91.4%) with BSI survived and 8 patients died (8.6% mortality rate). The overall incidence of thrombocytopenia among these 93 patients was 54.8% (51/93) and 100% (8/8) for the nonsurvivors. Out of the 85 survivors, 27 thrombocytopenic patients were hospitalized for >14 days versus 14 of nonthrombocytopenic patients (p = 0.007). Thrombocytopenia was associated with borderline significance with an increased LOS (adjusted odds ratio = 3.00, 95% confidence interval: 0.93–9.71, p = 0.066). Thrombocytopenia is common in critically ill pediatric patients with BSI and constitutes a simple and readily available risk marker for PICU LOS.

Biomarker combinations in predicting sepsis in hospitalized children with fever

Sepsis is among the leading causes of critical illness worldwide. It includes physiologic, pathologic, and biochemical abnormalities, induced by infection. Novel methods for recognizing a dysregulated inflammatory response and predicting associated mortality must be developed. Our aim was to investigate biomarkers that characterize a pro-inflammatory and anti-inflammatory response in patients with fever by comparing predictive validity for sepsis. 165 patients with fever were enrolled in this study, 55 of them had sepsis according to pSOFA criteria. All patients had blood samples drawn at the time of inclusion and after 24 h. CRP, PCT and also IL-6, IL-8 and sFAS levels were significantly higher in patients with sepsis. The AUC of CRP to predict sepsis was 0.799, all the other biomarkers had AUC's lower than that. Cytokines, when used as a single marker, did not show a significant diagnostic performance We analyzed various models of biomarker combinations. CRP combined with sFAS showed increase in sensitivity in predicting sepsis (88% vs. 83%). The highest AUC was achieved, when CRP, IL-6, sFAS and sVCAM-1 markers were combined 0.830 (95% CI 0.762-0.884) with a sensitivity of 70% and specificity of 84%. vs. 0.799 for CRP alone.

Surface TREM-1 as a Prognostic Biomarker in Pediatric Sepsis

OBJECTIVES

To investigate the association between the triggering receptor expressed on myeloid cells-1 (TREM-1) levels and prognosis in septic children.

METHODS

Patients admitted to pediatric intensive care units (PICU) of three tertiary centers were included in this prospective observational study. Serum samples were taken at admission from patients who were hospitalized with sepsis.

RESULTS

Of the 87 patients included, 34 (39.1%) had severe sepsis and 53 (60.9%) had septic shock. The median age was 2 y (2 mo to 16 y). TREM-1 values were found to be significantly higher in septic shock patients 129 pg/ml (min 9.85- max 494.90) compared to severe sepsis 105 pg/ml (min 8.21- max 289.17) (p = 0.048). Despite higher TREM-1 levels been measured in non-survivors compared to survivors, it was not statistically significant [168.98 pg/ml (min 9.85- max 494.90) vs. 110.79 pg/ml (min 8.21- max 408.90), (p = 0.075)].

CONCLUSIONS

Admission TREM-1 levels were higher in septic shock compared to severe sepsis patients. There was no association between mortality and TREM-1 levels in sepsis. TREM-1 measurements should be used carefully in pediatric sepsis prognosis.

Barriers and Proposed Solutions to a Successful Implementation of Pediatric Sepsis Protocols

The implementation of managed protocols contributes to a systematized approach to the patient and continuous evaluation of results, focusing on improving clinical practice, early diagnosis, treatment, and outcomes. Advantages to the adoption of a pediatric sepsis recognition and treatment protocol include: a reduction in time to start fluid and antibiotic administration, decreased kidney dysfunction and organ dysfunction, reduction in length of stay, and even a decrease on mortality. Barriers are: absence of a written protocol, parental knowledge, early diagnosis by healthcare professionals, venous access, availability of antimicrobials and vasoactive drugs, conditions of work, engagement of healthcare professionals. There are challenges in low-middle-income countries (LMIC). The causes of sepsis and resources differ from high-income countries. Viral agent such as dengue, malaria are common in LMIC and initial approach differ from bacterial infections. Some authors found increased or no impact in mortality or increased length of stay associated with the implementation of the SCC sepsis bundle which reinforces the importance of adapting it to most frequent diseases, disposable resources, and characteristics of healthcare professionals. Conclusions: (1) be simple; (2) be precise; (3) education; (5) improve communication; (5) work as a team; (6) share and celebrate results.

Glucocorticosteroids for sepsis in children. A protocol for a systematic review

BACKGROUND

Sepsis is the primary diagnosis in more than 8% of all critically ill children and sepsis is among the ten leading causes of death in children <10 years. Glucocorticosteroids are currently recommended in septic children with fluid or catecholamine resistant refractory shock. Glucocorticosteroids are widely used for severe sepsis in paediatric intensive care units worldwide. However, the evidence on the clinical effects of glucocorticosteroids for sepsis in children is unclear.

METHODS

We will perform a systematic review with meta-analysis and Trial Sequential Analysis of randomised clinical trials. We will include randomised clinical trials assessing the effects of glucocorticosteroids vs placebo or no intervention as an add-on therapy to standard care for sepsis in children. For the assessment of harms, we will also include quasi-randomised studies and observational studies identified during our searches for randomised clinical trials.

DISCUSSION

This review will seek to assess whether glucocorticosteroids indeed have their therapeutic place in the standard treatment for sepsis in children.

Risk Factors for Mortality in Pediatric Postsurgical versus Medical Severe Sepsis

BACKGROUND

Sepsis is a leading cause of morbidity and mortality after surgery. Most studies regarding sepsis do not differentiate between patients who have had recent surgery and those without. Few data exist regarding the risk factors for poor outcomes in pediatric postsurgical sepsis. Our hypothesis is pediatric postsurgical, and medical patients with severe sepsis have unique risk factors for mortality.

METHODS

Data were extracted from a secondary analysis of an international point prevalence study of pediatric severe sepsis. Sites included 128 pediatric intensive care units from 26 countries. Pediatric patients with severe sepsis were categorized into those who had recent surgery (postsurgical sepsis) versus those that did not (medical sepsis) before sepsis onset. Multivariable logistic regression models were used to determine risk factors for mortality.

RESULTS

A total of 556 patients were included: 138 with postsurgical and 418 with medical sepsis. In postsurgical sepsis, older age, admission from the hospital ward, multiple organ dysfunction syndrome at sepsis recognition, and cardiovascular and respiratory comorbidities were independent risk factors for death. In medical sepsis, resource-limited region, hospital-acquired infection, multiple organ dysfunction syndrome at sepsis recognition, higher Pediatric Index of Mortality-3 score, and malignancy were independent risk factors for death.

CONCLUSIONS

Pediatric patients with postsurgical sepsis had different risk factors for mortality compared with medical sepsis. This included a higher mortality risk in postsurgical patients presenting to the intensive care unit from the hospital ward. These data suggest an opportunity to develop and test early warning systems specific to pediatric sepsis in the postsurgical population.

Interventions for Pediatric Sepsis and Their Impact on Outcomes: A Brief Review

In the current era, pediatric sepsis remains a public health problem of significant prevalence and impact. With mortality rates practically unchanged over the years, this review hopes to briefly summarize the epidemiology and the current interventions for pediatric sepsis and point towards possible areas of improvement. Most pediatric studies of sepsis are either small, retrospective or observational. Given information technology spreading across country, and a stronger presence of clinical networks, development of multicenter prospective studies over the next decade should enable better treatments for pediatric sepsis, and improved outcomes.

Salivary biomarkers may measure stress responses in critically ill children

OBJECTIVE

Measurement of salivary biomarkers can provide important information regarding hypothalamic-pituitary-adrenal axis activity both under normal conditions as well as in response to psychological or physical stress. Our aim was to correlate salivary stress markers, such as cortisol, α-amylase and immunoglobulin A, with the Pediatric Risk Index Score of Mortality, underlying disease (pathologic, trauma and postoperative), need for mechanical ventilation/sedation and time lag between onset of illness and admission in children admitted in the pediatric intensive care unit.

METHODS

We enrolled 79 pediatric intensive care unit patients (2-14 years) over a 2-year period, which satisfy the including criteria, but finally salivary biomarkers were evaluated in 65 patients. Saliva samples were collected within 24 h of admission at 8 a.m., 2 p.m. and 8 p.m. to examine potential disruption of circadian rhythm.

RESULTS

Overall, the salivary biomarkers were increased; specifically, median values were (a) cortisol at 8 a.m.: 50.04 nmol/L, 2 p.m.: 30.69 nmol/L and 8 p.m.: 247.12 nmol/L; (b) α-amylase: at 8 a.m.: 22.567 U/L; 2 p.m.: 22.702 U/L and 8 p.m.: 21.484 U/L and (c) IgA at 8 a.m.: 95.10 mg/dL, 2 p.m.: 88.55 mg/dL and 8 p.m.: 80.80 mg/dL. Significantly higher levels were demonstrated in children younger than 6 years and those with Pediatric Risk Index Score of Mortality ⩾8 upon admission. Disturbances in circadian rhythm were observed. Cortisol circadian rhythm disturbance was observed only in children with Pediatric Risk Index Score of Mortality score ⩾8 upon admission while maintaining normal α-amylase circadian rhythm, which was associated with less than 3 days hospitalization in pediatric intensive care unit. No daily variance in IgA was observed.

CONCLUSION

Salivary biomarkers may serve, in critically ill children, as a sensitive, non-invasive method, important for the early recognition of those at high risk and guiding intervention, before clinical deterioration, promoting the quality of health care in pediatric population.

MicroRNA-326 aggravates acute lung injury in septic shock by mediating the NF-κB signaling pathway

Our previous studies have demonstrated that the activation of the nuclear factor-kappa B (NF-κB) signaling pathway contributes to the development of lipopolysaccharide (LPS)-induced acute lung injury (ALI) as well as an inflammatory reaction, and its inhibition may provide future therapeutic values. Thereby, this study aims to explore the effects of miR-326 on inflammatory response and ALI in mice with septic shock via the NF-κB signaling pathway. The study included normal mice and LPS-induced mouse models of septic shock with ALI. Modeled mice were transfected with the blank plasmid, miR-326 mimic, miR-326 inhibitor, si-BCL2A1 and miR-326 inhibitor + si-BCL2A1. Mean arterial pressure (MAP), airway pressure (AP), heart rate (HR) and lung wet dry (W/D) ratio were determined. Serum levels of interleukin (IL)-6, IL-10, IL-1β, and tumor necrosis factor-α (TNF-α) were detected using ELISA. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blot analysis were performed to detect the miR-326 expression and expression levels of BCL2A1, related genes of inflammatory response and the NF-κB signaling pathway in lung tissues. Cell viability and apoptosis were measured using the CCK-8 assay and flow cytometry, respectively. Compared to the ALI models and those transfected with blank plasmid, the up-regulated miR-326 expression and silenced BCL2A1 lead to decreased levels of MAP, increased AP, HR and lung W/D, increased serum levels of IL-6, IL-10, IL-1β and TNF-α, increased expressions of IL-6, IL-1β, TNF-α, NF-κB p65 (p-NF-κB p65), and iNOS with decreased expressions of BCL2A1s as well as inhibition of cell viability and enhanced cell apoptosis; the down-regulated miR-326 expression reversed the aforementioned situation. MiR-326 targeting the BCL2A1 gene activated the NF-κB signaling pathway, resulting in aggravated inflammatory response and lung injury of septic shock with ALI in mice.

Hypofibrinogenemia Is Associated With Poor Outcome and Secondary Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome in Pediatric Severe Sepsis

OBJECTIVES

Some children with sepsis exhibit a sustained hyperinflammatory response that can trigger secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome. Although hypofibrinogenemia is a shared feature of sepsis and hemophagocytic lymphohistiocytosis, there are no data about fibrinogen as a biomarker to identify children with sepsis/secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome overlap. We hypothesized that hypofibrinogenemia is associated with poor outcomes and secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome and has utility as a screening biomarker for this sepsis phenotype.

DESIGN

A retrospective cohort study of patients less than or equal to 21 years treated for severe sepsis from January 2012 to December 2014.

SETTING

Emergency department and PICU at a single academic children's hospital.

PATIENTS

Consecutive patients with greater than or equal to one episode of hypofibrinogenemia (serum fibrinogen < 150 mg/dL) within 7 days of sepsis were compared with a random sample of patients without hypofibrinogenemia using an a priori sample size target of 190. Thirty-eight patients with hypofibrinogenemia were compared with 154 without hypofibrinogenemia.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was "complicated course" (composite of 28-d mortality or ≥ two organ failures at 7 d). Secondary outcomes were 28-day mortality and fulfillment of diagnostic criteria for secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome. We used Wilcoxon rank-sum, Fisher exact test, and multivariable logistic regression to compare patients with versus without hypofibrinogenemia. Patients with hypofibrinogenemia were more likely to have a complicated course (73.7% vs 29.2%; p < 0.001), 28-day mortality (26.3% vs 7.1%, p = 0.002), and meet diagnostic criteria for secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome (21.1% vs 1.3%; p < 0.001). After controlling for confounders, hypofibrinogenemia remained associated with complicated course (adjusted odds ratio, 8.8; 95% CI, 3.5-22.4), mortality (adjusted odds ratio, 6.0; 95% CI, 2.0-18.1), and secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome (adjusted odds ratio, 27.6; 95% CI, 4.4-173).

CONCLUSIONS

Hypofibrinogenemia was independently associated with poor outcome and secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome in pediatric sepsis. Measurement of fibrinogen may provide a pragmatic biomarker to identify children with possible sepsis/secondary hemophagocytic lymphohistiocytosis/macrophage activation syndrome overlap for whom further diagnostic testing and consideration of adjunctive immunomodulatory therapies should be considered.

Olfactomedin-4 Is a Candidate Marker for a Pathogenic Neutrophil Subset in Septic Shock

OBJECTIVES

Heterogeneity in sepsis-related pathobiology presents a significant challenge. Resolving this heterogeneity presents an opportunity to understand pathobiology and improve patient care. Olfactomedin-4 is a neutrophil subset marker and may contribute to sepsis heterogeneity. Our objective was to evaluate the expression of olfactomedin-4 and characterize neutrophil heterogeneity in children with septic shock.

DESIGN

Single-center, prospective cohort, as well as secondary analysis of existing transcriptomic and proteomic databases.

SETTING

Tertiary care PICU.

PATIENTS

Patients from 5 days to 18 years old with septic shock were enrolled. Data collected included the expression of olfactomedin-4 messenger RNA, serum protein concentrations, and percentage of neutrophils that express olfactomedin-4.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Secondary analysis of existing transcriptomic data demonstrated that olfactomedin-4 is the most highly expressed gene in nonsurvivors of pediatric septic shock, compared with survivors. Secondary analysis of an existing proteomic database corroborated these observations. In a prospectively enrolled cohort, we quantified the percentage of olfactomedin-4+ neutrophils in patients with septic shock. Patients with a complicated course, defined as greater than or equal to two organ failures at day 7 of septic shock or 28-day mortality, had a higher percentage of olfactomedin-4+ neutrophils, compared with those without a complicated course. By logistic regression, the percentage of olfactomedin-4+ neutrophils was independently associated with increased risk of a complicated course (odds ratio, 1.09; 95% CI, 1.01-1.17; p = 0.024).

CONCLUSIONS

Olfactomedin-4 identifies a subpopulation of neutrophils in patients with septic shock, and those with a high percentage of olfactomedin-4+ neutrophils are at higher risk for greater organ failure burden and death. Olfactomedin-4 might serve as a marker of a pathogenic neutrophil subset in patients with septic shock.

Pediatric Sepsis Biomarker Risk Model-II: Redefining the Pediatric Sepsis Biomarker Risk Model With Septic Shock Phenotype

OBJECTIVE

The Pediatric Sepsis Biomarker Risk Model (PERSEVERE), a pediatric sepsis risk model, uses biomarkers to estimate baseline mortality risk for pediatric septic shock. It is unknown how PERSEVERE performs within distinct septic shock phenotypes. We tested PERSEVERE in children with septic shock and thrombocytopenia-associated multiple organ failure (TAMOF), and in those without new onset thrombocytopenia but with multiple organ failure (MOF).

DESIGN

PERSEVERE-based mortality risk was generated for each study subject (n = 660). A priori, we determined that if PERSEVERE did not perform well in both the TAMOF and the MOF cohorts, we would revise PERSEVERE to incorporate admission platelet counts.

SETTING

Multiple PICUs in the United States.

INTERVENTIONS

Standard care.

MEASUREMENTS AND MAIN RESULTS

PERSEVERE performed well in the TAMOF cohort (areas under the receiver operating characteristic curves [AUC], 0.84 [95% CI, 0.77-0.90]), but less well in the MOF cohort (AUC, 0.71 [0.61-0.80]). PERSEVERE was revised using 424 subjects previously reported in the derivation phase. PERSEVERE-II had an AUC of 0.89 (0.85-0.93) and performed equally well across TAMOF and MOF cohorts. PERSEVERE-II performed well when tested in 236 newly enrolled subjects. Sample size calculations for a clinical trial testing the efficacy of plasma exchange for children with septic shock and TAMOF indicated PERSEVERE-II-based stratification could substantially reduce the number of patients necessary, when compared with no stratification.

CONCLUSIONS

Testing PERSEVERE in the context of septic shock phenotypes prompted a revision incorporating platelet count. PERSEVERE-II performs well upon testing, independent of TAMOF or MOF status. PERSEVERE-II could potentially serve as a prognostic enrichment tool.

Glucocorticoid Receptor Polymorphisms and Outcomes in Pediatric Septic Shock

OBJECTIVE

Polymorphisms of the glucocorticoid receptor gene are associated with outcome and corticosteroid responsiveness among patients with inflammatory disorders. We conducted a candidate gene association study to test the hypothesis that these polymorphisms are associated with outcome and corticosteroid responsiveness among children with septic shock.

DESIGN

We genotyped 482 children with septic shock for the presence of two glucocorticoid receptor polymorphisms (rs56149945 and rs41423247) associated with increased sensitivity and one glucocorticoid receptor polymorphism (rs6198) associated with decreased sensitivity to corticosteroids. The primary outcome variable was complicated course, defined as 28-day mortality or the persistence of two or more organ failures 7 days after a septic shock diagnosis. We used logistic regression to test for an association between corticosteroid exposure and outcome, within genotype group, and adjusted for illness severity.

SETTING

Multiple PICUs in the United States.

INTERVENTIONS

Standard care.

MEASUREMENTS AND MAIN RESULTS

There were no differences in outcome when comparing the various genotype groups. Among patients homozygous for the wild-type glucocorticoid receptor allele, corticosteroids were independently associated with increased odds of complicated course (odds ratio, 2.30; 95% CI, 1.01-5.21; p = 0.047).

CONCLUSIONS

Based on these glucocorticoid receptor polymorphisms, we could not detect a beneficial effect of corticosteroids among any genotype group. Among children homozygous for the wild-type allele, corticosteroids were independently associated with increased odds of poor outcome.

[Methods of Molecular Transfusion in Intensive Care of Critical States in Pediatric Postoperative Cardiac Surgery Patients]

Molecular techniques in transfusion medicine have become popular in the clinical practice of pediatric intensive care units when the patient needs blood purification, more recently, in children in critical condition. Considering the anatomical and physiological characteristics of the child’s body, pronounced severity, and rapid progression of multiple organ disorders, the key problems defining the treatment results are instrument reading, choice and timely initiation of extracorporeal therapy. Today, along with the methods of renal replacement therapy in children albumin dialysis therapy and high-volume plasmapheresis are successfully applied in the treatment of acute liver dysfunction; extracorporeal membrane oxygenation — in the treatment of biventricular cardiac and/or respiratory failure. Selective endotoxin sorption methods (LPS-adsorption) are implemented in the treatment of severe gram-negative sepsis.

Etiology and prognostic factors of sepsis among children and adolescents admitted to the intensive care unit

Objective

To determine the etiology and clinical disease progression variables of sepsis associated with the prognosis of patients admitted to a pediatric intensive care unit.

Methods

Prospective and retrospective case series. Data were collected from the medical records of patients diagnosed with sepsis who were admitted to the pediatric intensive care unit of a general hospital from January 2011 to December 2013. Bacteria were identified in blood and fluid cultures. Age, sex, vaccination schedule, comorbidities, prior antibiotic use, clinical data on admission, and complications during disease progression were compared in the survival and death groups at a 5% significance level.

Results

A total of 115 patients, with a mean age of 30.5 months, were included in the study. Bacterial etiology was identified in 40 patients. Altered peripheral perfusion on admission and diagnosis of severe sepsis were associated with complications. A greater number of complications occurred in the group of patients older than 36 months (p = 0.003; odds ratio = 4.94). The presence of complications during hospitalization was associated with death (odds ratio = 27.7). The main etiological agents were Gram-negative bacteria (15/40), Staphylococcus aureus (11/40) and Neisseria meningitidis (5/40).

Conclusion

Gram-negative bacteria and Staphylococcus aureus predominated in the etiology of sepsis among children and adolescents admitted to an intensive care unit. The severity of sepsis and the presence of altered peripheral perfusion on admission were associated with complications. Moreover, the presence of complications was a factor associated with death.

Glucocorticoid Receptor Expression in Peripheral WBCs of Critically Ill Children

OBJECTIVES

To characterize glucocorticoid receptor expression in peripheral WBCs of critically ill children using flow cytometry.

DESIGN

Prospective observational cohort.

SETTING

A university-affiliated, tertiary PICU.

PATIENTS

Fifty-two critically ill children.

INTERVENTIONS

Samples collected for measurement of glucocorticoid receptor expression and parallel cortisol levels.

MEASUREMENTS AND MAIN RESULTS

Subjects with cardiovascular failure had significantly lower glucocorticoid receptor expression both in CD4 lymphocytes (mean fluorescence intensity, 522 [354-787] vs 830 [511-1,219]; p = 0.036) and CD8 lymphocytes (mean fluorescence intensity, 686 [350-835] vs 946 [558-1,511]; p = 0.019) compared with subjects without cardiovascular failure. Subjects in the upper 50th percentile of Pediatric Risk of Mortality III scores and organ failure also had significantly lower glucocorticoid receptor expression in CD4 and CD8 lymphocytes. There was no linear correlation between cortisol concentrations and glucocorticoid receptor expression.

CONCLUSIONS

Our study suggests that patients with shock and increased severity of illness have lower glucocorticoid receptor expression in CD4 and CD8 lymphocytes. Glucocorticoid receptor expression does not correlate well with cortisol levels. Future studies could focus on studying glucocorticoid receptor expression variability and isoform distribution in the pediatric critically ill population as well as on different strategies to optimize glucocorticoid response.

Developing a clinically feasible personalized medicine approach to pediatric septic shock

RATIONALE

Using microarray data, we previously identified gene expression-based subclasses of septic shock with important phenotypic differences. The subclass-defining genes correspond to adaptive immunity and glucocorticoid receptor signaling. Identifying the subclasses in real time has theranostic implications, given the potential for immune-enhancing therapies and controversies surrounding adjunctive corticosteroids for septic shock.

OBJECTIVES

To develop and validate a real-time subclassification method for septic shock.

METHODS

Gene expression data for the 100 subclass-defining genes were generated using a multiplex messenger RNA quantification platform (NanoString nCounter) and visualized using gene expression mosaics. Study subjects (n = 168) were allocated to the subclasses using computer-assisted image analysis and microarray-based reference mosaics. A gene expression score was calculated to reduce the gene expression patterns to a single metric. The method was tested prospectively in a separate cohort (n = 132).

MEASUREMENTS AND MAIN RESULTS

The NanoString-based data reproduced two septic shock subclasses. As previously, one subclass had decreased expression of the subclass-defining genes. The gene expression score identified this subclass with an area under the curve of 0.98 (95% confidence interval [CI95] = 0.96-0.99). Prospective testing of the subclassification method corroborated these findings. Allocation to this subclass was independently associated with mortality (odds ratio = 2.7; CI95 = 1.2-6.0; P = 0.016), and adjunctive corticosteroids prescribed at physician discretion were independently associated with mortality in this subclass (odds ratio = 4.1; CI95 = 1.4-12.0; P = 0.011).

CONCLUSIONS

We developed and tested a gene expression-based classification method for pediatric septic shock that meets the time constraints of the critical care environment, and can potentially inform therapeutic decisions.

Outcomes of pediatric patients with abdominal sepsis requiring surgery and extracorporeal membrane oxygenation using the Extracorporeal Life Support Organization database

No study describes the use of extracorporeal membrane oxygenation (ECMO) in pediatric patients with abdominal sepsis (AS) requiring surgery. A description of outcomes in this patient population would assist clinical decision-making and provide a context for discussions with patients and families. The Extracorporeal Life Support Organization database was queried for pediatric patients (30 days to 18 years) with AS requiring surgery. Forty-five of 61 patients survived (73.8%). Reported bleeding complications (57.1 vs 48.8%), the number of pre-ECMO ventilator hours (208.1 vs 178.9), and the timing of surgery before (50 vs 66.7%) and on-ECMO (50 vs 26.7%) were similar in survivors and nonsurvivors. Decreased pre-ECMO mean pH (7.1 vs 7.3) was associated with increased mortality (odds ratio, 1.49; 95% confidence interval, 1.04 to 2.14). ECMO use for pediatric patients with AS requiring surgery is associated with increased mortality and an increased rate of bleeding complications compared with all pediatric patients receiving ECMO support. Acidemia predicts mortality and provides a potential target of examination for future studies.

Outcomes of Pediatric Patients with Abdominal Sepsis Requiring Surgery and Extracorporeal Membrane Oxygenation Using the Extracorporeal Life Support Organization Database

No study describes the use of extracorporeal membrane oxygenation (ECMO) in pediatric patients with abdominal sepsis (AS) requiring surgery. A description of outcomes in this patient population would assist clinical decision-making and provide a context for discussions with patients and families. The Extracorporeal Life Support Organization database was queried for pediatric patients (30 days to 18 years) with AS requiring surgery. Forty-five of 61 patients survived (73.8%). Reported bleeding complications (57.1 vs 48.8%), the number of pre-ECMO ventilator hours (208.1 vs 178.9), and the timing of surgery before (50 vs 66.7%) and on-ECMO (50 vs 26.7%) were similar in survivors and nonsurvivors. Decreased pre-ECMO mean pH (7.1 vs 7.3) was associated with increased mortality (odds ratio, 1.49; 95% confidence interval, 1.04 to 2.14). ECMO use for pediatric patients with AS requiring surgery is associated with increased mortality and an increased rate of bleeding complications compared with all pediatric patients receiving ECMO support. Acidemia predicts mortality and provides a potential target of examination for future studies.

Corticosteroids and pediatric septic shock outcomes: a risk stratified analysis

Background

The potential benefits of corticosteroids for septic shock may depend on initial mortality risk.

Objective

We determined associations between corticosteroids and outcomes in children with septic shock who were stratified by initial mortality risk.

Methods

We conducted a retrospective analysis of an ongoing, multi-center pediatric septic shock clinical and biological database. Using a validated biomarker-based stratification tool (PERSEVERE), 496 subjects were stratified into three initial mortality risk strata (low, intermediate, and high). Subjects receiving corticosteroids during the initial 7 days of admission (n = 252) were compared to subjects who did not receive corticosteroids (n = 244). Logistic regression was used to model the effects of corticosteroids on 28-day mortality and complicated course, defined as death within 28 days or persistence of two or more organ failures at 7 days.

Results

Subjects who received corticosteroids had greater organ failure burden, higher illness severity, higher mortality, and a greater requirement for vasoactive medications, compared to subjects who did not receive corticosteroids. PERSEVERE-based mortality risk did not differ between the two groups. For the entire cohort, corticosteroids were associated with increased risk of mortality (OR 2.3, 95% CI 1.3–4.0, p = 0.004) and a complicated course (OR 1.7, 95% CI 1.1–2.5, p = 0.012). Within each PERSEVERE-based stratum, corticosteroid administration was not associated with improved outcomes. Similarly, corticosteroid administration was not associated with improved outcomes among patients with no comorbidities, nor in groups of patients stratified by PRISM.

Conclusions

Risk stratified analysis failed to demonstrate any benefit from corticosteroids in this pediatric septic shock cohort.

Corticosteroids are associated with repression of adaptive immunity gene programs in pediatric septic shock

RATIONALE

Corticosteroids are prescribed commonly for patients with septic shock, but their use remains controversial and concerns remain regarding side effects.

OBJECTIVES

To determine the effect of adjunctive corticosteroids on the genomic response of pediatric septic shock.

METHODS

We retrospectively analyzed an existing transcriptomic database of pediatric septic shock. Subjects receiving any formulation of systemic corticosteroids at the time of blood draw for microarray analysis were classified in the septic shock corticosteroid group. We compared normal control subjects (n = 52), a septic shock no corticosteroid group (n = 110), and a septic shock corticosteroid group (n = 70) using analysis of variance. Genes differentially regulated between the no corticosteroid group and the corticosteroid group were analyzed using Ingenuity Pathway Analysis.

MEASUREMENTS AND MAIN RESULTS

The two study groups did not differ with respect to illness severity, organ failure burden, mortality, or mortality risk. There were 319 gene probes differentially regulated between the no corticosteroid group and the corticosteroid group. These genes corresponded predominately to adaptive immunity-related signaling pathways, and were down-regulated relative to control subjects. Notably, the degree of down-regulation was significantly greater in the corticosteroid group, compared with the no corticosteroid group. A similar pattern was observed for genes corresponding to the glucocorticoid receptor signaling pathway.

CONCLUSIONS

Administration of corticosteroids in pediatric septic shock is associated with additional repression of genes corresponding to adaptive immunity. These data should be taken into account when considering the benefit to risk ratio of adjunctive corticosteroids for septic shock.

The pediatric sepsis biomarker risk model: potential implications for sepsis therapy and biology

Sepsis remains a major cause of morbidity and mortality in adult and pediatric intensive care units. Heterogeneity of demographics, comorbidities, biological mechanisms, and severity of illness leads to difficulty in determining which patients are at highest risk of mortality. Determining mortality risk is important for weighing the potential benefits of more aggressive interventions and for deciding whom to enroll in clinical trials. Biomarkers can be used to parse patients into different risk categories and can outperform current methods of patient risk stratification based on physiologic parameters. Here we review the Pediatric Sepsis Biomarker Risk Model that has also been modified and applied to estimate mortality risk in adult patients. We compare the two models and speculate on the biological implications of the biomarkers in patients with sepsis.

Performance of interleukin-27 as a sepsis diagnostic biomarker in critically ill adults

PURPOSE

We recently identified interleukin-27 (IL-27) as a sepsis diagnostic biomarker in children. Here we assess IL-27 as a sepsis diagnostic biomarker in critically ill adults with systemic inflammatory response syndrome and sepsis.

METHODS

IL-27 and procalcitonin (PCT) were measured from plasma samples in three groups: no sepsis (n = 78), pulmonary source of sepsis (n = 66), and non-pulmonary source of sepsis (n = 43). Receiver operating characteristic curves and classification and regression tree methodology were used to evaluate biomarker performance.

RESULTS

IL-27 did not discriminate effectively between sepsis and sterile systemic inflammatory response syndrome in unselected patients. The highest area under the curve (AUC) was 0.70 (95% C.I. 0.60 - 0.80) for IL-27 in subjects with a non-pulmonary source of sepsis. A decision tree incorporating IL-27, PCT, and age had an AUC of 0.79 (0.71-0.87) in subjects with a non-pulmonary source of sepsis. Compared to children with sepsis, adults with sepsis express less IL-27.

CONCLUSIONS

IL-27 performed overall poorly in this cohort as a sepsis diagnostic biomarker. Combining IL-27, PCT, and age reasonably estimated the risk of sepsis in subjects with a non-pulmonary source of sepsis. IL-27 may be a more reliable sepsis diagnostic biomarker in children than in adults.

The temporal version of the pediatric sepsis biomarker risk model

Background

PERSEVERE is a risk model for estimating mortality probability in pediatric septic shock, using five biomarkers measured within 24 hours of clinical presentation.

Objective

Here, we derive and test a temporal version of PERSEVERE (tPERSEVERE) that considers biomarker values at the first and third day following presentation to estimate the probability of a “complicated course”, defined as persistence of ≥2 organ failures at seven days after meeting criteria for septic shock, or death within 28 days.

Methods

Biomarkers were measured in the derivation cohort (n = 225) using serum samples obtained during days 1 and 3 of septic shock. Classification and Regression Tree (CART) analysis was used to derive a model to estimate the risk of a complicated course. The derived model was validated in the test cohort (n = 74), and subsequently updated using the combined derivation and test cohorts.

Results

A complicated course occurred in 23% of the derivation cohort subjects. The derived model had a sensitivity for a complicated course of 90% (95% CI 78–96), specificity was 70% (62–77), positive predictive value was 47% (37–58), and negative predictive value was 96% (91–99). The area under the receiver operating characteristic curve was 0.85 (0.79–0.90). Similar test characteristics were observed in the test cohort. The updated model had a sensitivity of 91% (81–96), a specificity of 70% (64–76), a positive predictive value of 47% (39–56), and a negative predictive value of 96% (92–99).

Conclusions

tPERSEVERE reasonably estimates the probability of a complicated course in children with septic shock. tPERSEVERE could potentially serve as an adjunct to physiological assessments for monitoring how risk for poor outcomes changes during early interventions in pediatric septic shock.

Testing the prognostic accuracy of the updated pediatric sepsis biomarker risk model

BACKGROUND

We previously derived and validated a risk model to estimate mortality probability in children with septic shock (PERSEVERE; PEdiatRic SEpsis biomarkEr Risk modEl). PERSEVERE uses five biomarkers and age to estimate mortality probability. After the initial derivation and validation of PERSEVERE, we combined the derivation and validation cohorts (n = 355) and updated PERSEVERE. An important step in the development of updated risk models is to test their accuracy using an independent test cohort.

OBJECTIVE

To test the prognostic accuracy of the updated version PERSEVERE in an independent test cohort.

METHODS

Study subjects were recruited from multiple pediatric intensive care units in the United States. Biomarkers were measured in 182 pediatric subjects with septic shock using serum samples obtained during the first 24 hours of presentation. The accuracy of PERSEVERE 28-day mortality risk estimate was tested using diagnostic test statistics, and the net reclassification improvement (NRI) was used to test whether PERSEVERE adds information to a physiology-based scoring system.

RESULTS

Mortality in the test cohort was 13.2%. Using a risk cut-off of 2.5%, the sensitivity of PERSEVERE for mortality was 83% (95% CI 62-95), specificity was 75% (68-82), positive predictive value was 34% (22-47), and negative predictive value was 97% (91-99). The area under the receiver operating characteristic curve was 0.81 (0.70-0.92). The false positive subjects had a greater degree of organ failure burden and longer intensive care unit length of stay, compared to the true negative subjects. When adding PERSEVERE to a physiology-based scoring system, the net reclassification improvement was 0.91 (0.47-1.35; p<0.001).

CONCLUSIONS

The updated version of PERSEVERE estimates mortality probability reliably in a heterogeneous test cohort of children with septic shock and provides information over and above a physiology-based scoring system.