Can generic scores (Pediatric Risk of Mortality and Pediatric Index of Mortality) replace specific scores in predicting the outcome of presumed meningococcal septic shock in children?

Comparison of pediatric scoring systems for mortality in septic patients and the impact of missing information on their predictive power: a retrospective analysis

Background

Scores can assess the severity and course of disease and predict outcome in an objective manner. This information is needed for proper risk assessment and stratification. Furthermore, scoring systems support optimal patient care, resource management and are gaining in importance in terms of artificial intelligence.

Objective

This study evaluated and compared the prognostic ability of various common pediatric scoring systems (PRISM, PRISM III, PRISM IV, PIM, PIM2, PIM3, PELOD, PELOD 2) in order to determine which is the most applicable score for pediatric sepsis patients in terms of timing of disease survey and insensitivity to missing data.

Methods

We retrospectively examined data from 398 patients under 18 years of age, who were diagnosed with sepsis. Scores were assessed at ICU admission and re-evaluated on the day of peak C-reactive protein. The scores were compared for their ability to predict mortality in this specific patient population and for their impairment due to missing data.

Results

PIM (AUC 0.76 (0.68-0.76)), PIM2 (AUC 0.78 (0.72-0.78)) and PIM3 (AUC 0.76 (0.68-0.76)) scores together with PRSIM III (AUC 0.75 (0.68-0.75)) and PELOD 2 (AUC 0.75 (0.66-0.75)) are the most suitable scores for determining patient prognosis at ICU admission. Once sepsis is pronounced, PELOD 2 (AUC 0.84 (0.77-0.91)) and PRISM IV (AUC 0.8 (0.72-0.88)) become significantly better in their performance and count among the best prognostic scores for use at this time together with PRISM III (AUC 0.81 (0.73-0.89)). PELOD 2 is good for monitoring and, like the PIM scores, is also largely insensitive to missing values.

Conclusion

Overall, PIM scores show comparatively good performance, are stable as far as timing of the disease survey is concerned, and they are also relatively stable in terms of missing parameters. PELOD 2 is best suitable for monitoring clinical course.

Global Case-Fatality Rates in Pediatric Severe Sepsis and Septic Shock: A Systematic Review and Meta-analysis

IMPORTANCE

The global patterns and distribution of case-fatality rates (CFRs) in pediatric severe sepsis and septic shock remain poorly described.

OBJECTIVE

We performed a systematic review and meta-analysis of studies of children with severe sepsis and septic shock to elucidate the patterns of CFRs in developing and developed countries over time. We also described factors associated with CFRs.

DATA SOURCES

We searched PubMed, Web of Science, Excerpta Medica database, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Cochrane Central systematically for randomized clinical trials and prospective observational studies from earliest publication until January 2017, using the keywords "pediatric," "sepsis," "septic shock," and "mortality."

STUDY SELECTION

Studies involving children with severe sepsis and septic shock that reported CFRs were included. Retrospective studies and studies including only neonates were excluded.

DATA EXTRACTION AND SYNTHESIS

We conducted our systematic review and meta-analysis in close accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled case-fatality estimates were obtained using random-effects meta-analysis. The associations of study period, study design, sepsis severity, age, and continents in which studies occurred were assessed with meta-regression.

MAIN OUTCOMES AND MEASURES

Meta-analyses to provide pooled estimates of CFR of pediatric severe sepsis and septic shock over time.

RESULTS

Ninety-four studies that included 7561 patients were included. Pooled CFRs were higher in developing countries (31.7% [95% CI, 27.3%-36.4%]) than in developed countries (19.3% [95% CI, 16.4%-22.7%]; P < .001). Meta-analysis of CFRs also showed significant heterogeneity across studies. Continents that include mainly developing countries reported higher CFRs (adjusted odds ratios: Africa, 7.89 [95% CI, 6.02-10.32]; P < .001; Asia, 3.81 [95% CI, 3.60-4.03]; P < .001; South America, 2.91 [95% CI, 2.71-3.12]; P < .001) than North America. Septic shock was associated with higher CFRs than severe sepsis (adjusted odds ratios, 1.47 [95% CI, 1.41-1.54]). Younger age was also a risk factor (adjusted odds ratio, 0.95 [95% CI, 0.94-0.96] per year of increase in age). Earlier study eras were associated with higher CFRs (adjusted odds ratios for 1991-2000, 1.24 [95% CI, 1.13-1.37]; P < .001) compared with 2011 to 2016. Time-trend analysis showed higher CFRs over time in developing countries than developed countries.

CONCLUSIONS AND RELEVANCE

Despite the declining trend of pediatric severe sepsis and septic shock CFRs, the disparity between developing and developed countries persists. Further characterizations of vulnerable populations and collaborations between developed and developing countries are warranted to reduce the burden of pediatric sepsis globally.

Prediction of pediatric sepsis mortality within 1 h of intensive care admission

PURPOSE

The definitions of sepsis and septic shock have recently been revised in adults, but contemporary data are needed to inform similar approaches in children.

METHODS

Multicenter cohort study including children <16 years admitted with sepsis or septic shock to ICUs in Australia and New Zealand in the period 2012-2015. We assessed septic shock criteria at ICU admission to define sepsis severity, using 30-day mortality as outcome. Through multivariable logistic regression, a pediatric sepsis score was derived using variables available within 60 min of ICU admission.

RESULTS

Of 42,523 pediatric admissions, 4403 children were admitted with invasive infection, including 1697 diagnosed as having sepsis/septic shock on admission. Mortality was 8.5% (144/1697) and 50.7% of deaths occurred within 48 h of admission. The presence of septic shock as defined by the 2005 consensus was sensitive but not specific in predicting mortality (AUC = 0.69; 95% CI 0.65-0.72). Combinations of hypotension, vasopressor therapy, and lactate >2 mmol/l discriminated poorly (AUC <0.60). Multivariate models showed that oxygenation markers, ventilatory support, hypotension, cardiac arrest, serum lactate, pupil responsiveness, and immunosuppression were the best-performing predictors (0.843; 0.811-0.875). We derived a pediatric sepsis score (0.817; 0.779-0.855), and every one-point increase was associated with a 28.5% (23.8-33.2%) increase in the odds of death. Children with a score ≥6 had 19.8% mortality and accounted for 74.3% of deaths. The sepsis score performed comparably when applied to all children admitted with invasive infection (0.810; 0.781-0.840).

CONCLUSIONS

We observed mortality patterns specific to pediatric sepsis that support the need for specialized definitions of sepsis severity in children. We demonstrated the importance of lactate, cardiovascular, and respiratory derangements at ICU admission for the identification of children with substantially higher risk of sepsis mortality.

A Valuable Tool in Predicting Poor Outcome due to Sepsis in Pediatric Intensive Care Unit: Tp-e/QT Ratio

OBJECTIVE

To assess the feasibility of 12-lead electrocardiographic (ECG) measures such as P wave dispersion (PWd), QT interval, QT dispersion (QTd), Tp-e interval, Tp-e/QT and Tp-e/QTc ratio in predicting poor outcome in patients diagnosed with sepsis in pediatric intensive care unit (PICU).

METHODS

Ninety-three patients diagnosed with sepsis, severe sepsis or septic shock and 103 age- and sex-matched healthy children were enrolled into the study. PWd, QT interval, QTd, Tp-e interval and Tp-e/QT, Tp-e/QTc ratios were obtained from a 12-lead electrocardiogram.

RESULTS

PWd, QTd, Tp-e interval and Tp-e/QT, Tp-e/QTc ratios were significantly higher in septic patients compared with the controls. During the study period, 41 patients had died. In multivariate logistic regression analyses, only Tp-e/QT ratio was found to be an independent predictor of mortality.

CONCLUSION

The ECG measurements can predict the poor outcome in patients with sepsis. The Tp-e/QT ratio may be a valuable tool in predicting mortality for patients with sepsis in the PICU.

Prognostic markers of meningococcal disease in children: recent advances and future challenges

Meningococcal disease is a life-threatening condition and a major cause of bacterial meningitis and sepsis worldwide. In many fatal cases, meningococcal disease is rapidly progressive and death occurs within hours of the initial symptoms. The early identification of patients at high risk of death would be useful in order to provide aggressive and more personalized clinical management with the proper level of supportive therapy required, contributing to an improvement in the survival rate and reduction in sequelae. The current study aims to review the current published literature about prognostic markers of meningococcal sepsis in children in order to elaborate conclusions and recommendations that could guide clinical practice and further research.

Using data-driven rules to predict mortality in severe community acquired pneumonia

Prediction of patient-centered outcomes in hospitals is useful for performance benchmarking, resource allocation, and guidance regarding active treatment and withdrawal of care. Yet, their use by clinicians is limited by the complexity of available tools and amount of data required. We propose to use Disjunctive Normal Forms as a novel approach to predict hospital and 90-day mortality from instance-based patient data, comprising demographic, genetic, and physiologic information in a large cohort of patients admitted with severe community acquired pneumonia. We develop two algorithms to efficiently learn Disjunctive Normal Forms, which yield easy-to-interpret rules that explicitly map data to the outcome of interest. Disjunctive Normal Forms achieve higher prediction performance quality compared to a set of state-of-the-art machine learning models, and unveils insights unavailable with standard methods. Disjunctive Normal Forms constitute an intuitive set of prediction rules that could be easily implemented to predict outcomes and guide criteria-based clinical decision making and clinical trial execution, and thus of greater practical usefulness than currently available prediction tools. The Java implementation of the tool JavaDNF will be publicly available.

The product of platelet and neutrophil counts (PN product) at presentation as a predictor of outcome in children with meningococcal disease

BACKGROUND

Despite improvement in the treatment of Neisseria meningitidis infection, meningococcal diseases (MD) are still an important cause of morbidity and mortality around the world. This study assessed the performance of the product of platelet and neutrophil counts (PN product) at the time of presentation to hospital as a predictor of outcome in children with MD.

METHODS

Retrospective evaluation of children with clinical MD admitted to two paediatric intensive care units in Brazil.

RESULTS

Seventy-two children aged 2-156 months were studied. Overall mortality was 19.7%. The PN product, the Glasgow Meningococcal Septicaemia Prognostic Score and the Paediatric Risk of Mortality score discriminated between survivors and non-survivors. A PN < or = 113 had a sensitivity of 28.6% (95% CI 8.6-58.1), specificity of 96.6% (95% CI 88.1-99.5) and positive and negative predictive values of 66.7% and 84.8%. The area under the receiver operating characteristic curve was 0.85 (95% CI 0.74-0.92).

CONCLUSION

The PN product had a lower performance than reported in previous studies from a developed country. The PN product, however, is a good indicator of mortality in MD but needs to be validated for the population to which it is being applied.

A new scoring system derived from base excess and platelet count at presentation predicts mortality in paediatric meningococcal sepsis

INTRODUCTION

The aim of this study was to derive a novel prognostic score for mortality in paediatric meningococcal sepsis (MS) based on readily available laboratory markers.

METHODS

A multicentre retrospective cohort study for the consortium set and a single centre retrospective study for replication set. The consortium set were 1,073 children (age 1 week to 17.9 years) referred over a 15-year period (1996 to 2011), who had an admission diagnosis of MS, referred to paediatric intensive care units (PICUs) in six different European centres. The consortium set was split into a development set and validation set to derive the score. The replication set were 134 children with MS (age 2 weeks to 16 years) referred over a 4-year period (2007 to 2011) to PICUs via the Children's Acute Transport Service (CATS), London.

RESULTS

A total of 85/1,073 (7.9%) children in the consortium set died. A total of 16/134 (11.9%) children in the replication set died. Children dying in the consortium set had significantly lower base excess, C-reactive protein (CRP), platelet and white cell count, more deranged coagulation and higher lactate than survivors. Paediatric risk of mortality (PRISM) score, Glasgow meningococcal septicaemia prognosis score (GMSPS) and Rotterdam score were also higher. Using the consortium set, a new scoring system using base excess and platelet count at presentation, termed the BEP score, was mathematically developed and validated. BEP predicted mortality with high sensitivity and specificity scores (area under the curve (AUC) in the validation set=0.86 and in the replication set=0.96). In the validation set, BEP score performance (AUC=0.86, confidence interval (CI): 0.80 to 0.91) was better than GMSPS (AUC=0.77, CI: 0.68, 0.85), similar to Rotterdam (AUC=0.87, CI: 0.81 to 0.93) and not as good as PRISM (AUC=0.93, CI: 0.85 to 0.97).

CONCLUSIONS

The BEP score, relying on only two variables that are quickly and objectively measurable and readily available at presentation, is highly sensitive and specific in predicting death from MS in childhood.

Mortality prediction models for pediatric intensive care: comparison of overall and subgroup specific performance

AIM

To validate paediatric index of mortality (PIM) and pediatric risk of mortality (PRISM) models within the overall population as well as in specific subgroups in pediatric intensive care units (PICUs).

METHODS

Variants of PIM and PRISM prediction models were compared with respect to calibration (agreement between predicted risks and observed mortality) and discrimination (area under the receiver operating characteristic curve, AUC). We considered performance in the overall study population and in subgroups, defined by diagnoses, age and urgency at admission, and length of stay (LoS) at the PICU. We analyzed data from consecutive patients younger than 16 years admitted to the eight PICUs in the Netherlands between February 2006 and October 2009. Patients referred to another ICU or deceased within 2 h after admission were excluded.

RESULTS

A total of 12,040 admissions were included, with 412 deaths. Variants of PIM2 were best calibrated. All models discriminated well, also in patients <28 days of age (neonates), with overall higher AUC for PRISM variants (PIM = 0.83, PIM2 = 0.85, PIM2-ANZ06 = 0.86, PIM2-ANZ08 = 0.85, PRISM = 0.88, PRISM3-24 = 0.90). Best discrimination for PRISM3-24 was confirmed in 13 out of 14 subgroup categories. After recalibration PRISM3-24 predicted accurately in most (12 out of 14) categories. Discrimination was poorer for all models (AUC < 0.73) after LoS of >6 days at the PICU.

CONCLUSION

All models discriminated well, also in most subgroups including neonates, but had difficulties predicting mortality for patients >6 days at the PICU. In a western European setting both the PIM2(-ANZ06) or a recalibrated version of PRISM3-24 are suited for overall individualized risk prediction.

Application of the pediatric risk of mortality (PRISM) score and determination of mortality risk factors in a tertiary pediatric intensive care unit

INTRODUCTION

To establish disease severity at admission can be performed by way of the mortality prognostic. Nowadays the prognostic scores make part of quality control and research. The Pediatric Risk of Mortality is one of the scores used in the pediatric intensive care units.

OBJECTIVES

The purpose of this study is the utilization of the pediatric risk of mortality to determine mortality risk factors in a tertiary pediatric intensive care units.

METHODS

Retrospective cohort study, in a period of one year, at a general tertiary pediatric intensive care unit. The pediatric risk of mortality scores corresponding to the first 24 hours of hospitalization were recorded; additional data were collected to characterize the study population.

RESULTS

359 patients were included; the variables that were found to be risk factors for death were multiple organ dysfunction syndrome, mechanical ventilation, use of vasoactive drugs, hospital-acquired infection, parenteral nutrition and duration of hospitalization (p < 0,0001). Fifty-four patients (15%) died; median pediatric risk of mortality score was significantly lower in patients who survived (p=0,0001). The ROC curve yielded a value of 0.76 (CI 95% 0,69-0,83) and the calibration was shown to be adequate.

DISCUSSION

It is imperative for pediatric intensive care units to implement strict quality controls to identify groups at risk of death and to ensure the adequacy of treatment. Although some authors have shown that the PRISM score overestimates mortality and that it is not appropriate in specific pediatric populations, in this study pediatric risk of mortality showed satisfactory discriminatory performance in differentiating between survivors and non-survivors.

CONCLUSIONS

The pediatric risk of mortality score showed adequate discriminatory capacity and thus constitutes a useful tool for the assessment of prognosis for pediatric patients admitted to a tertiary pediatric intensive care units.

Nuclear factor-kappaB activation in peripheral blood mononuclear cells in children with sepsis

OBJECTIVE

To determine the activation of nuclear factor-[kappa]B in peripheral blood CD14+ monocyte/macrophages and CD3+, CD4+, and CD8+ T cells in children with sepsis.

DESIGN

Observational study.

SETTING

University hospital.

PATIENTS

Twenty-six children with sepsis (nine females and 17 males, aged between 10 days and 15 yrs; median, 4.3 yrs) on admission to our hospital between August 1999 and November 2005.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The percentages of peripheral blood CD14+ monocyte/macrophages and CD3+, CD4+, and CD8+ T cells exhibiting nuclear factor-[kappa]B activity were determined by flow cytometry. In addition, relationships among the degree to which nuclear factor-[kappa]B was activated, serum levels of cytokines (interferon-[gamma], tumor necrosis factor-[alpha], interleukin-2, interleukin-4, interleukin-6, and interleukin-10), and clinical variables were analyzed. The percentage of cells exhibiting nuclear factor-[kappa]B activity was increased among CD14+, CD3+, CD4+, and CD8+ cells in the sepsis group and was significantly higher among CD14+, CD3+, and CD4+ cells of the patients with severe sepsis (n = 9) than those of patients with nonsevere sepsis (n = 17). The percentage of cells exhibiting nuclear factor-[kappa]B activity was significantly higher among CD14+ cells than CD3+ cells in the patients with severe sepsis. In addition, this percentage was significantly higher among CD14+ cells than CD3+, CD4+, and CD8+ cells in septic patients who had positive blood cultures (n = 16). Serum interleukin-6 levels were correlated with the percentages of CD14+, CD3+, CD4+, and CD8+ cells exhibiting nuclear factor-[kappa]B activity, and serum IL-10 levels were correlated with the percentages of CD14+, CD3+, and CD4+ cells exhibiting nuclear factor-[kappa]B activity.

CONCLUSIONS

Nuclear factor-[kappa]B in peripheral blood mononuclear cells was activated in children with sepsis and was related the severity of sepsis.

High mortality of invasive pneumococcal disease compared with meningococcal disease in critically ill children

OBJECTIVE

To ascertain outcome, patterns of disease, incidence of concurrent infection, superinfection and penicillin resistance in children requiring intensive care for Streptococcus pneumoniae infection and compare it to a similar disease pattern, namely Neisseria meningitidis b infection.

DESIGN AND SETTING

Prospective cohort study in a regional paediatric intensive care unit (PICU).

PATIENTS AND PARTICIPANTS

Children with invasive pneumococcal and meningococcal disease requiring intensive care.

MEASUREMENTS AND RESULTS

The study included 22 children with invasive pneumococcal disease (IPD), median age 14 months (interquartile range 3-52), median Paediatric Index of Mortality (PIM) 0.051 (0.028-0.066), median length of PICU stay 8.5 days (4-13). Four patients died, three (13.5%) attributable to IPD. Incidence of concurrent infection 27%. There were no superinfections. All S. pneumoniae were sensitive to cefotaxime; one isolate (3.7%) was resistant to penicillin. There were 186 children with meningococcal disease (MD), with a higher PIM (median 0.068, 0.033-0.108), older age (29 months, 10.7-77.9) and shorter length of PICU stay (median 3 days, 2-6). Eight (4.3%) children died from MD. Incidence of concurrent and superinfection was 18% and 6%, respectively in children with MD. All N. meningitidis cases were sensitive to cefotaxime and penicillin. The standardized mortality ratio was considerably higher with IPD (2.0) than with MD (0.52).

CONCLUSIONS

In invasive pneumococcal disease preventative measures including early recognition, immediate antibiotic therapy and vaccination need to be taken in the community, similar to the control of meningococcal disease. Invasive pneumococcal disease should command the same respect as meningococcal disease.

Diagnosing meningococcemia as a cause of sepsis

OBJECTIVE

In 2004, a consensus meeting of critical care and infectious disease experts was organized to review and make recommendations on current definitions of infections, sepsis, and organ failure for neonates and children and for the predisposing conditions leading to these diseases. Among the infections leading to sepsis, meningococcemia is so distinguishable that a separate article on its diagnosis and management was thought to be warranted.

DESIGN AND METHODS

The process included a modified Delphi method, a consensus conference, subsequent smaller meetings of subgroups and key individuals, and electronic-based discussion among subgroups. A systematic review of the literature was undertaken.

CONCLUSIONS

Early recognition and treatment of likely meningococcal sepsis has led to decreased mortality. Since the start of vaccination against serogroup C, the prevalence of this disease has decreased. Not only the possible presence of a meningococcal sepsis is important, but also the assessment of the shock state and the severity of disease and the possible presence of meningoencephalitis. There are also a number of genetic predispositions determining the severity of disease. The only three randomized trials in this disease have led to the conclusion that mortality is not a stable end point. Improvement in organ function, morbidity (including amputations), and functional outcome are better outcome measures.

Severity of illness and organ dysfunction scoring in children

OBJECTIVE

To describe predictive and descriptive general scores that can be used to estimate the severity of illness in critically ill children.

DESIGN

Review of the medical literature.

SETTING

Pediatric intensive care units (PICUs).

PATIENTS

Critically ill children.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two predictive scores are frequently used in PICUs: the Pediatric Risk of Mortality III score and the Pediatric Index of Mortality 2. The data considered in these scores are collected at baseline. Predictive scores can be used to compare expected and observed mortality in PICUs or to estimate the balance in the baseline severity of illness of patients included in the different arms of a randomized clinical trial. Only one descriptive score is validated to estimate the severity of cases of multiple organ dysfunction syndrome in PICUs, namely, the Pediatric Logistic Organ Dysfunction score. The data required to calculate this score are collected from baseline to discharge from the PICU or up to 2 hrs before death in the PICU. The Pediatric Logistic Organ Dysfunction score can be used to describe the clinical outcome of patients during their stay in a PICU.

CONCLUSION

Pediatric Risk of Mortality III, Pediatric Index of Mortality 2, and Pediatric Logistic Organ Dysfunction scores are the best available tools to estimate the severity of illness in critically ill children.

Simplified PRISM III score and outcome in the pediatric intensive care unit

BACKGROUND

To evaluate the association of the PRISM III (pediatric risk of mortality) score with the infant outcome in the pediatric intensive care unit (PICU), and to determine if this score could be simplified.

METHODS

A prospective cohort study was carried out with 170 infants who were consecutively admitted to the PICU. The PRISM III score with 17 physiologic variables was performed during the first 8 h of admission to the unit. Statistical analysis was done with logistic regression, odds ratios (OR) with 95% confidence intervals (95% CI), and receiver operating curve. The Alfa value was set at 0.05.

RESULTS

There were 42 deaths (24.7%). The two main causes of death were septic shock (28.6%) and head trauma (16.7%). The PRISM III score had a sensitivity of 0.71, and a specificity of 0.64 as a mortality predictor. Out of the 17 physiologic variables only four of them were significant: abnormal pupillary reflexes OR 9.9 (95% CI, 3.5-28.4), acidosis OR 3.1 (95% CI, 2.0-4.9), blood urea nitrogen concentration OR 1.03 (95% CI, 1.01-1.04), and white blood cell count OR 1.02 (95% CI, 1.01-1.03). The whole logistic regression model had a coefficient of determination R(2) = 0.219, P < 0.001.

CONCLUSIONS

In this setting, the PRISM III score had good sensitivity and specificity to predict mortality. This score could be simplified using only the four variables that were significant in this study. This modified PRISM III score could reduce the cost of patient care especially in developing countries PICU.

Early application of generic mortality risk scores in presumed meningococcal disease

OBJECTIVE

Mortality from meningococcal disease typically occurs within 24 hrs of intensive care unit (ICU) admission. An early, accurate mortality-risk tool may aid in trial design for novel therapies. We assessed the performance of two generic scores that assign mortality risk within 1 hr of ICU admission: the Preintensive Care Pediatric Risk of Mortality (Pre-ICU PRISM) and Pediatric Index of Mortality (PIM).

DESIGN

Prospective, observational study over 21 months.

SETTING

Two tertiary pediatric ICUs accepting referrals from southeast England.

PATIENTS

Patients were 165 consecutive children with meningococcal disease. Ages ranged from 0.1 to 17 yrs (median 2.3 yrs).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

PIM demonstrated greater sensibility, with complete data collected in 93% of cases, compared with 35% for the pre-ICU PRISM. Both scores discriminated well. The area under the receiver operating characteristic curve was 0.90 (95% confidence interval, 0.81-1.00) for PIM and 0.94 (95% confidence interval, 0.88-0.98) for Pre-ICU PRISM; this did not change when applied to the subgroup of patients with complete data. Both scores calibrated poorly, overestimating mortality in the medium-risk strata (and also in the high-risk stratum in the case of Pre-ICU PRISM). When used as a stratification tool for a hypothetical trial (60% reduction in mortality, 80% power), the scores allowed for a reduction in study size by 50% (PIM) and 43% (pre-ICU PRISM).

CONCLUSIONS

Pre-ICU PRISM and PIM both discriminate well but calibrate poorly when applied to a cohort of children with meningococcal sepsis. Both scores provide an effective means of stratification for clinical trial purposes. The main advantage for PIM appears to be ease of data collection.

The immunopathogenesis of meningococcal disease

This review describes the mechanisms of the immune response to meningococcal disease, examining the extent to which individual variation of the immune response can determine susceptibility. It concludes by summarising the difficulties encountered by recent efforts to develop new immunomodulatory treatments.

Recent innovations in intensive care unit risk-prediction models

During the past 20 years, ICU risk-prediction models have undergone significant development, validation, and refinement. Among the general ICU severity of illness scoring systems, the Acute Physiology and Chronic Health Evaluation (APACHE), Mortality Prediction Model (MPM), and the Simplified Acute Physiology Score (SAPS) have become the most accepted and used. To risk-adjust patients with longer, more severe illnesses like sepsis and acute respiratory distress syndrome, several models of organ dysfunction or failure have become available, including the Multiple Organ Dysfunction Score (MODS), the Sequential Organ Failure Assessment (SOFA), and the Logistic Organ Dysfunction Score (LODS). Recent innovations in risk adjustment include automatic physiology and diagnostic variable retrieval and the use of artificial intelligence. These innovations have the potential of extending the uses of case-mix and severity-of-illness adjustment in the areas of clinical research, patient care, and administration. The challenges facing intensivists in the next few years are to further develop these models so that they can be used throughout the IUC stay to assess quality of care and to extend them to more specific patient groups such as the elderly and patients with chronic ICU courses.

Meningococcal disease: how to prevent and how to manage

Meningococcal disease is a significant problem in the paediatric population. The diagnosis of meningococcal disease can be problematic and progression of the disease can rapidly lead to a life-threatening illness. Despite the success of antibiotic treatment, mortality rates remain high. The development of protein-polysaccharide conjugate vaccines has significantly improved the success of vaccination in reducing the incidence of meningococcal disease. However, a comprehensive vaccine conferring protection against disease-associated serogroups remains elusive. The aim of this review is to highlight recent significant improvements in the prevention and management of meningococcal disease.

[Treatment of meningococcal purpura fulminans]

In France, the incidence of meningococcal infections is increasing. The most severe presentation, called purpura fulminans, has a death rate of 20-25%; 5 to 20% of the survivors need skin grafts and/or amputations. Diagnosis of invasive meningococcal infection is very difficult when purpura and "toxic" appearance are absent: one should take into account parents' impression of their ill child. This diagnosis must be evoked in any child presenting with febrile purpura (like in the United Kingdom, parents should be encouraged to use the "tumbler test" to identify a vasculitic rash); a fulminant form is to be suspected in the presence of only one ecchymosis and signs of infection, remembering that recognition of shock is difficult in children. Recently, the Health Authority has recommended to administer a third generation cephalosporin promptly (before biological investigations) for any child with signs of infection and a necrotic or ecchymotic purpura (> 3 mm of diameter), and then to refer the patient to the hospital. By grouping the patients from 7 studies, it can be observed that preadmission antibiotic administration has a protective effect on mortality (odds ratio: 0.36; 95% confidence interval: 0.23-0.56); a negative effect was observed in only one of these series. Children with purpura fulminans should be referred to a paediatric intensive care unit. Management includes antibiotics, steroids, fluid resuscitation and catecholamines (be aware of hypoglycaemia, particularly in infants, and hypocalcaemia). Treatment of cutaneous necrosis and distal ischemia is difficult and still controversial: antithrombin, protein C, tissue plasminogen activator and vasodilator infusion have no proven efficacy. Cases must be rapidly notified to the Public Health Service who will institute chemoprophylaxis for close contacts. Given the predominance of serogroup B in France, we hope that an efficient vaccine will soon become available.