Critical Organ Dysfunction and Preoperative Mortality in Newborns with Hypoplastic Left Heart Syndrome.

Hypoplastic left heart syndrome (HLHS) is fatal without surgical intervention. An important subset of HLHS patients die prior to surgical intervention, but this population is underevaluated. The neonatal sequential organ failure assessment score (nSOFA) is an operational definition of organ dysfunction that can identify those with a high risk of mortality among neonatal intensive care unit (NICU) patients. The utility of the nSOFA to predict preoperative mortality in the unique HLHS population is unknown and could inform care, particularly care provided by neonatology staff. We performed a multicenter retrospective cohort study of HLHS cases across three level IV NICUs from January 1, 2009 to December 3, 2023. Patients were classified as either survived or died prior to surgical intervention. Demographic variables were curated from medical records including the maximum nSOFA (nSOFAmax) before surgical intervention or death. We identified 265 patients with HLHS over the study period. The nSOFAmax was greater in patients who died preoperatively (14/265; 5%) compared with survivors to surgical intervention (median 8 [interquartile range, 6, 12] vs. 2 [0, 4]; p < 0.001). The area under receiver operating characteristics curve for the nSOFAmax to discriminate for mortality was 0.93 (95% confidence interval, 0.88-0.98; p < 0.001). Compared with an nSOFAmax of 0, the likelihood ratio for preoperative death doubled at 2, tripled at 4, and was 10-fold at 9. This is the first demonstration of nSOFA utility in specific to congenital heart disease and HLHS. The nSOFAmax represents a novel, electronic health record-compatible, and generalizable method to identify patient-level organ dysfunction and risk for preoperative mortality in HLHS patients. KEY POINTS: · An important subset of HLHS patients die preoperatively.. · nSOFA can be used to measure preoperative HLHS severity.. · nSOFA predicts preoperative mortality risk in HLHS patients..

International Consensus Criteria for Pediatric Sepsis and Septic Shock.

Importance: Sepsis is a leading cause of death among children worldwide. Current pediatric-specific criteria for sepsis were published in 2005 based on expert opinion. In 2016, the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) defined sepsis as life-threatening organ dysfunction caused by a dysregulated host response to infection, but it excluded children. Objective: To update and evaluate criteria for sepsis and septic shock in children. Evidence Review: The Society of Critical Care Medicine (SCCM) convened a task force of 35 pediatric experts in critical care, emergency medicine, infectious diseases, general pediatrics, nursing, public health, and neonatology from 6 continents. Using evidence from an international survey, systematic review and meta-analysis, and a new organ dysfunction score developed based on more than 3 million electronic health record encounters from 10 sites on 4 continents, a modified Delphi consensus process was employed to develop criteria. Findings: Based on survey data, most pediatric clinicians used sepsis to refer to infection with life-threatening organ dysfunction, which differed from prior pediatric sepsis criteria that used systemic inflammatory response syndrome (SIRS) criteria, which have poor predictive properties, and included the redundant term, severe sepsis. The SCCM task force recommends that sepsis in children be identified by a Phoenix Sepsis Score of at least 2 points in children with suspected infection, which indicates potentially life-threatening dysfunction of the respiratory, cardiovascular, coagulation, and/or neurological systems. Children with a Phoenix Sepsis Score of at least 2 points had in-hospital mortality of 7.1% in higher-resource settings and 28.5% in lower-resource settings, more than 8 times that of children with suspected infection not meeting these criteria. Mortality was higher in children who had organ dysfunction in at least 1 of 4-respiratory, cardiovascular, coagulation, and/or neurological-organ systems that was not the primary site of infection. Septic shock was defined as children with sepsis who had cardiovascular dysfunction, indicated by at least 1 cardiovascular point in the Phoenix Sepsis Score, which included severe hypotension for age, blood lactate exceeding 5 mmol/L, or need for vasoactive medication. Children with septic shock had an in-hospital mortality rate of 10.8% and 33.5% in higher- and lower-resource settings, respectively. Conclusions and Relevance: The Phoenix sepsis criteria for sepsis and septic shock in children were derived and validated by the international SCCM Pediatric Sepsis Definition Task Force using a large international database and survey, systematic review and meta-analysis, and modified Delphi consensus approach. A Phoenix Sepsis Score of at least 2 identified potentially life-threatening organ dysfunction in children younger than 18 years with infection, and its use has the potential to improve clinical care, epidemiological assessment, and research in pediatric sepsis and septic shock around the world.

Development and Validation of the Phoenix Criteria for Pediatric Sepsis and Septic Shock.

Importance: The Society of Critical Care Medicine Pediatric Sepsis Definition Task Force sought to develop and validate new clinical criteria for pediatric sepsis and septic shock using measures of organ dysfunction through a data-driven approach. Objective: To derive and validate novel criteria for pediatric sepsis and septic shock across differently resourced settings. Design, Setting, and Participants: Multicenter, international, retrospective cohort study in 10 health systems in the US, Colombia, Bangladesh, China, and Kenya, 3 of which were used as external validation sites. Data were collected from emergency and inpatient encounters for children (aged <18 years) from 2010 to 2019: 3 049 699 in the development (including derivation and internal validation) set and 581 317 in the external validation set. Exposure: Stacked regression models to predict mortality in children with suspected infection were derived and validated using the best-performing organ dysfunction subscores from 8 existing scores. The final model was then translated into an integer-based score used to establish binary criteria for sepsis and septic shock. Main Outcomes and Measures: The primary outcome for all analyses was in-hospital mortality. Model- and integer-based score performance measures included the area under the precision recall curve (AUPRC; primary) and area under the receiver operating characteristic curve (AUROC; secondary). For binary criteria, primary performance measures were positive predictive value and sensitivity. Results: Among the 172 984 children with suspected infection in the first 24 hours (development set; 1.2% mortality), a 4-organ-system model performed best. The integer version of that model, the Phoenix Sepsis Score, had AUPRCs of 0.23 to 0.38 (95% CI range, 0.20-0.39) and AUROCs of 0.71 to 0.92 (95% CI range, 0.70-0.92) to predict mortality in the validation sets. Using a Phoenix Sepsis Score of 2 points or higher in children with suspected infection as criteria for sepsis and sepsis plus 1 or more cardiovascular point as criteria for septic shock resulted in a higher positive predictive value and higher or similar sensitivity compared with the 2005 International Pediatric Sepsis Consensus Conference (IPSCC) criteria across differently resourced settings. Conclusions and Relevance: The novel Phoenix sepsis criteria, which were derived and validated using data from higher- and lower-resource settings, had improved performance for the diagnosis of pediatric sepsis and septic shock compared with the existing IPSCC criteria.

Neonatal sepsis definitions from randomised clinical trials.

INTRODUCTION: Neonatal sepsis is a leading cause of infant mortality worldwide with non-specific and varied presentation. We aimed to catalogue the current definitions of neonatal sepsis in published randomised controlled trials (RCTs). METHOD: A systematic search of the Embase and Cochrane databases was performed for RCTs which explicitly stated a definition for neonatal sepsis. Definitions were sub-divided into five primary criteria for infection (culture, laboratory findings, clinical signs, radiological evidence and risk factors) and stratified by qualifiers (early/late-onset and likelihood of sepsis). RESULTS: Of 668 papers screened, 80 RCTs were included and 128 individual definitions identified. The single most common definition was neonatal sepsis defined by blood culture alone (n = 35), followed by culture and clinical signs (n = 29), and then laboratory tests/clinical signs (n = 25). Blood culture featured in 83 definitions, laboratory testing featured in 48 definitions while clinical signs and radiology featured in 80 and 8 definitions, respectively. DISCUSSION: A diverse range of definitions of neonatal sepsis are used and based on microbiological culture, laboratory tests and clinical signs in contrast to adult and paediatric sepsis which use organ dysfunction. An international consensus-based definition of neonatal sepsis could allow meta-analysis and translate results to improve outcomes.

Reporting of Social Determinants of Health in Pediatric Sepsis Studies.

OBJECTIVE: Standardized, consistent reporting of social determinants of health (SDOH) in studies on children with sepsis would allow for: 1) understanding the association of SDOH with illness severity and outcomes, 2) comparing populations and extrapolating study results, and 3) identification of potentially modifiable socioeconomic factors for policy makers. We, therefore, sought to determine how frequently data on SDOH were reported, which factors were collected and how these factors were defined in studies of sepsis in children. DATA SOURCES AND SELECTION: We reviewed 106 articles (published between 2005 and 2020) utilized in a recent systematic review on physiologic criteria for pediatric sepsis. DATA EXTRACTION: Data were extracted by two reviewers on variables that fell within the World Health Organization's SDOH categories. DATA SYNTHESIS: SDOH were not the primary outcome in any of the included studies. Seventeen percent of articles (18/106) did not report on any SDOH, and a further 36.8% (39/106) only reported on gender/sex. Of the remaining 46.2% of articles, the most reported SDOH categories were preadmission nutritional status (35.8%, 38/106) and race/ethnicity (18.9%, 20/106). However, no two studies used the same definition of the variables reported within each of these categories. Six studies reported on socioeconomic status (3.8%, 6/106), including two from upper-middle-income and four from lower middle-income countries. Only three studies reported on parental education levels (2.8%, 3/106). No study reported on parental job security or structural conflict. CONCLUSIONS: We found overall low reporting of SDOH and marked variability in categorizations and definitions of SDOH variables. Consistent and standardized reporting of SDOH in pediatric sepsis studies is needed to understand the role these factors play in the development and severity of sepsis, to compare and extrapolate study results between settings and to implement policies aimed at improving socioeconomic conditions related to sepsis.

Hourly Kinetics of Critical Organ Dysfunction in Extremely Preterm Infants.

Rationale: Use of severity of illness scores to classify patients for clinical care and research is common outside of the neonatal ICU. Extremely premature (<29 weeks' gestation) infants with extremely low birth weight (<1,000 g) experience significant mortality and develop severe pathology during the protracted birth hospitalization. Objectives: To measure at high resolution the changes in organ dysfunction that occur from birth to death or discharge home by gestational age and time, and among extremely preterm infants with and without clinically meaningful outcomes using the neonatal sequential organ failure assessment score. Methods: A single-center, retrospective, observational cohort study of inborn, extremely preterm infants with extremely low birth weight admitted between January 2012 and January 2020. Neonatal sequential organ failure assessment scores were calculated every hour for every patient from admission until death or discharge. Measurements and Main Results: Longitudinal, granular scores from 436 infants demonstrated early and sustained discrimination of those who died versus those who survived to discharge. The discrimination for mortality by the maximum score was excellent (area under curve, 0.91; 95% confidence intervals, 0.88-0.94). Among survivors with and without adverse outcomes, most score variation occurred at the patient level. The weekly average score over the first 28 days was associated with the sum of adverse outcomes at discharge. Conclusions: The neonatal sequential organ failure assessment score discriminates between survival and nonsurvival on the first day of life. The major contributor to score variation occurred at the patient level. There was a direct association between scores and major adverse outcomes, including death.

Sepsis and Mortality Prediction in Very Low Birth Weight Infants: Analysis of HeRO and nSOFA.

OBJECTIVE: Scores to predict sepsis or define sepsis severity could improve care for very low birth weight (VLBW) infants. The heart rate characteristics (HRC) index (HeRO score) was developed as an early warning system for late-onset sepsis (LOS), and also rises before necrotizing enterocolitis (NEC). The neonatal sequential organ failure assessment (nSOFA) was developed to predict sepsis-associated mortality using respiratory, hemodynamic, and hematologic data. The aim of this study was to analyze the HRC index and nSOFA near blood cultures in VLBW infants relative to diagnosis and sepsis-associated mortality. STUDY DESIGN: Retrospective, single-center study of VLBW infants from 2011 to 2019. We analyzed HRC index and nSOFA around blood cultures diagnosed as LOS/NEC. In a subgroup of the cohort, we analyzed HRC and nSOFA near the first sepsis-like illness (SLI) or sepsis ruled-out (SRO) compared with LOS/NEC. We compared scores by diagnosis and mortality during treatment. RESULTS: We analyzed 179 LOS/NEC, 93 SLI, and 96 SRO blood culture events. In LOS/NEC, the HRC index increased before the blood culture, while nSOFA increased at the time of culture. Both scores were higher in nonsurvivors compared with survivors and in LOS/NEC compared with SRO. The nSOFA 12 hours after the time of blood culture predicted mortality during treatment better than any other time point analyzed (area under the curve 0.91). CONCLUSION: The HRC index provides earlier warning of imminent sepsis, whereas nSOFA after blood culture provides better prediction of mortality. KEY POINTS: · The HRC index and nSOFA provide complementary information on sepsis risk and sepsis-related mortality risk.. · This study adds to existing literature evaluating these risk scores independently by analyzing them together and in cases of not only proven but also suspected infections.. · The impact of combining risk models could be improved outcomes for premature infants..

Criteria for Pediatric Sepsis-A Systematic Review and Meta-Analysis by the Pediatric Sepsis Definition Taskforce.

OBJECTIVE: To determine the associations of demographic, clinical, laboratory, organ dysfunction, and illness severity variable values with: 1) sepsis, severe sepsis, or septic shock in children with infection and 2) multiple organ dysfunction or death in children with sepsis, severe sepsis, or septic shock. DATA SOURCES: MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched from January 1, 2004, and November 16, 2020. STUDY SELECTION: Case-control studies, cohort studies, and randomized controlled trials in children greater than or equal to 37-week-old postconception to 18 years with suspected or confirmed infection, which included the terms "sepsis," "septicemia," or "septic shock" in the title or abstract. DATA EXTRACTION: Study characteristics, patient demographics, clinical signs or interventions, laboratory values, organ dysfunction measures, and illness severity scores were extracted from eligible articles. Random-effects meta-analysis was performed. DATA SYNTHESIS: One hundred and six studies met eligibility criteria of which 81 were included in the meta-analysis. Sixteen studies (9,629 patients) provided data for the sepsis, severe sepsis, or septic shock outcome and 71 studies (154,674 patients) for the mortality outcome. In children with infection, decreased level of consciousness and higher Pediatric Risk of Mortality scores were associated with sepsis/severe sepsis. In children with sepsis/severe sepsis/septic shock, chronic conditions, oncologic diagnosis, use of vasoactive/inotropic agents, mechanical ventilation, serum lactate, platelet count, fibrinogen, procalcitonin, multi-organ dysfunction syndrome, Pediatric Logistic Organ Dysfunction score, Pediatric Index of Mortality-3, and Pediatric Risk of Mortality score each demonstrated significant and consistent associations with mortality. Pooled mortality rates varied among high-, upper middle-, and lower middle-income countries for patients with sepsis, severe sepsis, and septic shock (p < 0.0001). CONCLUSIONS: Strong associations of several markers of organ dysfunction with the outcomes of interest among infected and septic children support their inclusion in the data validation phase of the Pediatric Sepsis Definition Taskforce.

Neonatal sepsis: a systematic review of core outcomes from randomised clinical trials.

BACKGROUND: The lack of a consensus definition of neonatal sepsis and a core outcome set (COS) proves a substantial impediment to research that influences policy and practice relevant to key stakeholders, patients and parents. METHODS: A systematic review of the literature was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. In the included studies, the described outcomes were extracted in accordance with the provisions of the Core Outcome Measures in Effectiveness Trials (COMET) handbook and registered. RESULTS: Among 884 abstracts identified, 90 randomised controlled trials (RCTs) were included in this review. Only 30 manuscripts explicitly stated the primary and/or secondary outcomes. A total of 88 distinct outcomes were recorded across all 90 studies included. These were then assigned to seven different domains in line with the taxonomy for classification proposed by the COMET initiative. The most frequently reported outcome was survival with 74% (n = 67) of the studies reporting an outcome within this domain. CONCLUSIONS: This systematic review constitutes one of the initial phases in the protocol for developing a COS in neonatal sepsis. The paucity of standardised outcome reporting in neonatal sepsis hinders comparison and synthesis of data. The final phase will involve a Delphi Survey to generate a COS in neonatal sepsis by consensus recommendation. IMPACT: This systematic review identified a wide variation of outcomes reported among published RCTs on the management of neonatal sepsis. The paucity of standardised outcome reporting hinders comparison and synthesis of data and future meta-analyses with conclusive recommendations on the management of neonatal sepsis are unlikely. The final phase will involve a Delphi Survey to determine a COS by consensus recommendation with input from all relevant stakeholders.

Multicenter Validation of the Neonatal Sequential Organ Failure Assessment Score for Prognosis in the Neonatal Intensive Care Unit.

Infants in the neonatal intensive care unit are at risk of life-threatening organ dysfunction, but few objective tools with utility exist. In a multicenter cohort of 20 152 infants, we show the neonatal sequential organ failure assessment score had good-to-excellent discrimination of mortality across centers, birth weights, and time points after admission.

Contribution of Concurrent Comorbidities to Sepsis-Related Mortality in Preterm Infants ≤32 Weeks of Gestation at an Academic Neonatal Intensive Care Network.

OBJECTIVE: This study sought to identify concurrent major comorbidities in preterm infants ≤32 weeks of gestation that may have contributed to sepsis-related mortality following a diagnosis of bacteremia or blood culture-negative sepsis within the neonatal period (≤28 days of life). STUDY DESIGN: This is a retrospective chart review of infants ≤32 weeks of gestation who were admitted to a single academic network of multiple neonatal intensive care units between January 1, 2012, and December 31, 2015, to determine the primary cause(s) and timing of death in those diagnosed with bacteremia or blood culture-negative sepsis. Direct comparisons between early-onset sepsis (EOS; ≤72 hours) and late-onset sepsis (LOS; >72 hours) were made. RESULTS: In our study cohort, of 939 total patients with ≤32 weeks of gestation, 182 infants were diagnosed with 198 episodes of sepsis and 7.7% (14/182) died. Mortality rates did not significantly differ between neonates with bacteremia or blood culture-negative sepsis (7/14 each group), and those diagnosed with EOS compared with LOS (6/14 vs. 8/14). Nearly 80% (11/14) of infants were transitioned to comfort care prior to their death secondary to a coinciding diagnosis of severe grade-3 or -4 intraventricular hemorrhage, periventricular leukomalacia, necrotizing enterocolitis, and/or intestinal perforation. CONCLUSION: Preexisting comorbidities commonly associated with extreme preterm birth contributed to sepsis-related mortality in our patient cohort. KEY POINTS: · Concurrent comorbidities contribute to, and may artificially inflate, sepsis-related mortality.. · Absence of a consensus definition for neonatal sepsis complicates the investigation of infection.. · Accurate assessment of the incidence of sepsis in very low birth weight infants is vital for future investigations.

A neonatal sequential organ failure assessment score predicts mortality to late-onset sepsis in preterm very low birth weight infants.

BACKGROUND: An operational definition of organ dysfunction applicable to neonates that predicts mortality in the setting of infection is lacking. We determined the utility of an objective, electronic health record (EHR)-automated, neonatal sequential organ failure assessment (nSOFA) score to predict mortality from late-onset sepsis (LOS) in premature, very low birth weight (VLBW) infants. METHODS: Retrospective, single-center study of bacteremic preterm VLBW newborns admitted between 2012 and 2016. nSOFA scores were derived for patients with LOS at multiple time points surrounding the sepsis evaluation. RESULTS: nSOFA scores at evaluation and at all points measured after evaluation were different between survivors and non-survivors. Among patients with an nSOFA score of >4, mortality was higher at evaluation (13% vs 67%, p < 0.001), +6 h (15% vs 64%, p = 0.002), and +12 h (7% vs 71%, p < 0.001) as compared to patients with a score of ≤4. Receiver operating characteristics area under the curve was 0.77 at evaluation (95% CI 0.62-0.92; p = 0.001), 0.78 at +6 h (0.66-0.92; p < 0.001), and 0.93 at +12 h (0.86-0.997; p < 0.001). CONCLUSIONS: The nSOFA scoring system predicted mortality in VLBW infants with LOS and this automated system was integrated into our EHR. Prediction of LOS mortality is a critical step toward improvements in neonatal sepsis outcomes.

Challenges in developing a consensus definition of neonatal sepsis.

Sepsis remains a leading cause of morbidity and mortality in the neonatal population, and at present, there is no unified definition of neonatal sepsis. Existing consensus sepsis definitions within paediatrics are not suited for use in the NICU and do not address sepsis in the premature population. Many neonatal research and surveillance networks have criteria for the definition of sepsis within their publications though these vary greatly and there is typically a heavy emphasis on microbiological culture. The concept of organ dysfunction as a diagnostic criterion for sepsis is rarely considered in neonatal literature, and it remains unclear how to most accurately screen neonates for organ dysfunction. Accurately defining and screening for sepsis is important for clinical management, health service design and future research. The progress made by the Sepsis-3 group provides a roadmap of how definitions and screening criteria may be developed. Similar initiatives in neonatology are likely to be more challenging and would need to account for the unique presentation of sepsis in term and premature neonates. The outputs of similar consensus work within neonatology should be twofold: a validated definition of neonatal sepsis and screening criteria to identify at-risk patients earlier in their clinical course. IMPACT: There is currently no consensus definition of neonatal sepsis and the definitions that are currently in use are varied.A consensus definition of neonatal sepsis would benefit clinicians, patients and researchers.Recent progress in adults with publication of Sepsis-3 provides guidance on how a consensus definition and screening criteria for sepsis could be produced in neonatology.We discuss common themes and potential shortcomings in sepsis definitions within neonatology.We highlight the need for a consensus definition of neonatal sepsis and the challenges that this task poses.

Cutting Edge: IL-1α and Not IL-1ß Drives IL-1R1-Dependent Neonatal Murine Sepsis Lethality.

Sepsis disproportionately affects the very old and the very young. IL-1 signaling is important in innate host defense but may also play a deleterious role in acute inflammatory conditions (including sepsis) by promulgating life-threatening inflammation. IL-1 signaling is mediated by two distinct ligands: IL-1α and IL-1ß, both acting on a common receptor (IL-1R1). IL-1R1 targeting has not reduced adult human sepsis mortality despite biologic plausibility. Because the specific role of IL-1α or IL-1ß in sepsis survival is unknown in any age group and the role of IL-1 signaling remains unknown in neonates, we studied the role of IL-1 signaling, including the impact of IL-1α and IL-1ß, on neonatal murine sepsis survival. IL-1 signaling augments the late plasma inflammatory response to sepsis. IL-1α and not IL-1ß is the critical mediator of sepsis mortality, likely because of paracrine actions within the tissue. These data do not support targeting IL-1 signaling in neonates.

Neonatal CD71+ Erythroid Cells Do Not Modify Murine Sepsis Mortality.

Sepsis is a major cause of neonatal mortality and morbidity worldwide. A recent report suggested that murine neonatal host defense against infection could be compromised by immunosuppressive CD71(+) erythroid splenocytes. We examined the impact of CD71(+) erythroid splenocytes on murine neonatal mortality to endotoxin challenge or polymicrobial sepsis and characterized circulating CD71(+) erythroid (CD235a(+)) cells in human neonates. Adoptive transfer or an Ab-mediated reduction in neonatal CD71(+) erythroid splenocytes did not alter murine neonatal survival to endotoxin challenge or polymicrobial sepsis challenge. Ex vivo immunosuppression of stimulated adult CD11b(+) cells was not limited to neonatal splenocytes; it also occurred with adult and neonatal bone marrow. Animals treated with anti-CD71 Ab showed reduced splenic bacterial load following bacterial challenge compared with isotype-treated mice. However, adoptive transfer of enriched CD71(+) erythroid splenocytes to CD71(+)-reduced animals did not reduce bacterial clearance. Human CD71(+)CD235a(+) cells were common among cord blood mononuclear cells and were shown to be reticulocytes. In summary, a lack of effect on murine survival to polymicrobial sepsis following adoptive transfer or diminution of CD71(+) erythroid splenocytes under these experimental conditions suggests that the impact of these cells on neonatal infection risk and progression may be limited. An unanticipated immune priming effect of anti-CD71 Ab treatment, rather than a reduction in immunosuppressive CD71(+) erythroid splenocytes, was likely responsible for the reported enhanced bacterial clearance. In humans, the well-described rapid decrease in circulating reticulocytes after birth suggests that they may have a limited role in reducing inflammation secondary to microbial colonization.

TRIF-dependent innate immune activation is critical for survival to neonatal gram-negative sepsis.

Current evidence suggests that neonatal immunity is functionally distinct from adults. Although TLR signaling through the adaptor protein, MyD88, has been shown to be critical for survival to sepsis in adults, little is known about the role of MyD88 or TRIF in neonatal sepsis. We demonstrate that TRIF(-/-) but not MyD88(-/-) neonates are highly susceptible to Escherichia coli peritonitis and bacteremia. This was associated with decreased innate immune recruitment and function. Importantly, we found that the reverse was true in adults that MyD88(-/-) but not TRIF(-/-) or wild-type adults are susceptible to E. coli peritonitis and bacteremia. In addition, we demonstrate that TRIF but not MyD88 signaling is critical for the TLR4 protective adjuvant effect we have previously demonstrated. These data suggest a differential requirement for the survival of neonates versus adults to Gram-negative infection, and that modulation of TRIF in neonates can be used to augment survival to neonatal sepsis.

Timing of Multiorgan Dysfunction among Hospitalized Infants with Fatal Fulminant Sepsis.

Objective Identify the progression of specific signs of multiorgan dysfunction among infants with fatal sepsis. Study Design Cohort study of 679 infants who died within 3 days of the start of a late-onset sepsis (LOS) episode in neonatal intensive care units from 1997 to 2012. We extracted clinical and laboratory data on the day of death (day 0) and the preceding 5 days (days -5 to -1). Results Median (25th percentile-75th percentile) gestational age was 25 (24-28) weeks. Compared with day -1, day 0 was characterized by an increased requirement for mechanical ventilation and higher mean fraction of inspired oxygen. Measures of cardiorespiratory support and the proportion of infants with neutropenia began to rise on day -2. Conclusion Hospitalized infants with fatal LOS manifest respiratory, cardiovascular, renal, immune, and hematologic dysfunction. Knowledge of these factors and their timing may be important for the development and testing of novel therapeutics to reduce sepsis mortality.

Matrix Metalloproteinase-8 Augments Bacterial Clearance in a Juvenile Sepsis Model.

Genetic ablation or pharmacologic inhibition of matrix metalloproteinase-8 (MMP8) improves survival in an adult murine sepsis model. Because developmental age influences the host inflammatory response, we hypothesized that developmental age influences the role of MMP8 in sepsis. First, we compared sepsis survival between wild type (WT, C57BL/6) and MMP8 null juvenile-aged mice (12-14 days) after intraperitoneal injection of a standardized cecal slurry. Second, peritoneal lavages collected at 6 and 18 hours after cecal slurry injection were analyzed for bacterial burden, leukocyte subsets, and inflammatory cytokines. Third, juvenile WT mice were pretreated with an MMP8 inhibitor prior to cecal slurry injection; analysis of their bacterial burden was compared to vehicle-injected animals. Fourth, the phagocytic capacity of WT and MMP8 null peritoneal macrophages was compared. Finally, peritoneal neutrophil extracellular traps (NETs) were compared using immunofluorescent imaging and quantitative image analysis. We found that juvenile MMP8 null mice had greater mortality and higher bacterial burden than WT mice. Leukocyte counts and cytokine concentrations in the peritoneal fluid were increased in the MMP8 null mice, relative to the wild type mice. Peritoneal macrophages from MMP8 null mice had reduced phagocytic capacity compared to WT macrophages. There was no quantitative difference in NET formation, but fewer bacteria were adherent to NETs from MMP8 null animals. In conclusion, in contrast to septic adult mice, genetic ablation of MMP8 increased mortality following bacterial peritonitis in juvenile mice. The increase in mortality in MMP8 null juvenile mice was associated with reduced bacterial clearance and reduced NET efficiency. We conclude that developmental age influences the role of MMP8 in sepsis.

Defining neonatal sepsis.

PURPOSE OF REVIEW: Although infection rates have modestly decreased in the neonatal intensive care unit (NICU) as a result of ongoing quality improvement measures, neonatal sepsis remains a frequent and devastating problem among hospitalized preterm neonates. Despite multiple attempts to address this unmet need, there have been minimal advances in clinical management, outcomes, and accuracy of diagnostic testing options over the last 3 decades. One strong contributor to a lack of medical progress is a variable case definition of disease. The inability to agree on a precise definition greatly reduces the likelihood of aligning findings from epidemiologists, clinicians, and researchers, which, in turn, severely hinders progress toward improving outcomes. RECENT FINDINGS: Pediatric consensus definitions for sepsis are not accurate in term infants and are not appropriate for preterm infants. In contrast to the defined multistage criteria for other devastating diseases encountered in the NICU (e.g., bronchopulmonary dysplasia), there is significant variability in the criteria used by investigators to substantiate the diagnosis of neonatal sepsis. SUMMARY: The lack of an accepted consensus definition for neonatal sepsis impedes our efforts toward improved diagnostic and prognostic options, and accurate outcomes information for this vulnerable population.