The epidemiology of severe sepsis in England, Wales and Northern Ireland, 1996 to 2004: secondary analysis of a high quality clinical database, the ICNARC Case Mix Programme Database

INTRODUCTION: To evaluate the impact of recent evidence-based treatments for severe sepsis in routine clinical care requires an understanding of the underlying epidemiology, particularly with regard to trends over time. We interrogated a high quality clinical database to examine trends in the incidence and mortality of severe sepsis over a nine-year period. METHODS: Admissions with severe sepsis occurring at any time within 24 hours of admission to critical care were identified to an established methodology using raw physiological data from the Intensive Care National Audit & Research Centre (ICNARC) Case Mix Programme Database, containing data from 343,860 admissions to 172 adult, general critical care units in England, Wales and Northern Ireland between December 1995 and January 2005. Generalised linear models were used to assess changes in the incidence, case mix, outcomes and activity of these admissions. RESULTS: In total, 92,672 admissions (27.0%) were identified as having severe sepsis in the first 24 hours following admission. The percentage of admissions with severe sepsis during the first 24 hours rose from 23.5% in 1996 to 28.7% in 2004. This represents an increase from an estimated 18,500 to 31,000 admissions to all 240 adult, general critical care units in England, Wales and Northern Ireland. Hospital mortality for admissions with severe sepsis decreased from 48.3% in 1996 to 44.7% in 2004, but the total number of deaths increased from an estimated 9,000 to 14,000. The treated incidence of severe sepsis per 100,000 population rose from 46 in 1996 to 66 in 2003, with the associated number of hospital deaths per 100,000 population rising from 23 to 30. CONCLUSION: The population incidence of critical care admission with severe sepsis during the first 24 hours and associated hospital deaths are increasing. These baseline data provide essential information to those wishing to evaluate the introduction of the Surviving Sepsis Campaign care bundles in UK hospitals

Case mix, outcomes and comparison of risk prediction models for admissions to adult, general and specialist critical care units for head injury: a secondary analysis of the ICNARC Case Mix Programme Database

INTRODUCTION: This report describes the case mix and outcome (mortality, intensive care unit (ICU) and hospital length of stay) for admissions to ICU for head injury and evaluates the predictive ability of five risk adjustment models. METHODS: A secondary analysis was conducted of data from the Intensive Care National Audit and Research Centre (ICNARC) Case Mix Programme, a high quality clinical database, of 374,594 admissions to 171 adult critical care units across England, Wales and Northern Ireland from 1995 to 2005. The discrimination and calibration of five risk prediction models, SAPS II, MPM II, APACHE II and III and the ICNARC model plus raw Glasgow Coma Score (GCS) were compared. RESULTS: There were 11,021 admissions following traumatic brain injury identified (3% of all database admissions). Mortality in ICU was 23.5% and in-hospital was 33.5%. Median ICU and hospital lengths of stay were 3.2 and 24 days, respectively, for survivors and 1.6 and 3 days, respectively, for non-survivors. The ICNARC model, SAPS II and MPM II discriminated best between survivors and non-survivors and were better calibrated than raw GCS, APACHE II and III in 5,393 patients eligible for all models. CONCLUSION: Traumatic brain injury requiring intensive care has a high mortality rate. Non-survivors have a short length of ICU and hospital stay. APACHE II and III have poorer calibration and discrimination than SAPS II, MPM II and the ICNARC model in traumatic brain injury; however, no model had perfect calibration

Outcomes following oesophagectomy in patients with oesophageal cancer: a secondary analysis of the ICNARC Case Mix Programme Database

Introduction: This report describes the case mix and outcomes of patients with oesophageal cancer admitted to adult critical care units following elective oesophageal surgery in England, Wales and Northern Ireland. Methods: Admissions to critical care following elective oesophageal surgery for malignancy were identified using data from the Intensive Care National Audit and Research Centre (ICNARC) Case Mix Programme Database. Information on admissions between December 1995 and September 2007 were extracted and the association between in-hospital mortality and patient characteristics on admission to critical care was assessed using multiple logistic regression analysis. The performance of three prognostic models (Simplified Acute Physiology Score (SAPS) II, Acute Physiology and Chronic Health Evaluation (APACHE) II and the ICNARC physiology score) was also evaluated. Results: Between 1995 and 2007, there were 7227 admissions to 181 critical care units following oesophageal surgery for malignancy. Overall mortality in critical care was 4.4% and in-hospital mortality was 11%, although both declined steadily over time. Eight hundred and seventy-three (12.2%) patients were readmitted to critical care, most commonly for respiratory complications (49%) and surgical complications (25%). Readmitted patients had a critical care unit mortality of 24.7% and in-hospital mortality of 33.9%. Overall in-hospital mortality was associated with patient age, and various physiological measurements on admission to critical care (partial pressure of arterial oxygen (PaO2):fraction of inspired oxygen (FiO2) ratio, lowest arterial pH, mechanical ventilation, serum albumin, urea and creatinine). The three prognostic models evaluated performed poorly in measures of discrimination, calibration and goodness of fit. Conclusions: Surgery for oesophageal malignancy continues to be associated with significant morbidity and mortality. Age and organ dysfunction in the early postoperative period are associated with an increased risk of death. Postoperative serum albumin is confirmed as an additional prognostic factor. More work is required to determine how this knowledge may improve clinical management

Spatial organization of the kelp microbiome at micron scales

Background: Elucidating the spatial structure of host-associated microbial communities is essential for understanding taxon-taxon interactions within the microbiota and between microbiota and host. Macroalgae are colonized by complex microbial communities, suggesting intimate symbioses that likely play key roles in both macroalgal and bacterial biology, yet little is known about the spatial organization of microbes associated with macroalgae. Canopy-forming kelp are ecologically significant, fixing teragrams of carbon per year in coastal kelp forest ecosystems. We characterized the micron-scale spatial organization of bacterial communities on blades of the kelp Nereocystis luetkeana using fluorescence in situ hybridization and spectral imaging with a probe set combining phylum-, class-, and genus-level probes to localize and identify > 90% of the microbial community. Results: We show that kelp blades host a dense microbial biofilm composed of disparate microbial taxa in close contact with one another. The biofilm is spatially differentiated, with clustered cells of the dominant symbiont Granulosicoccus sp. (Gammaproteobacteria) close to the kelp surface and filamentous Bacteroidetes and Alphaproteobacteria relatively more abundant near the biofilm-seawater interface. A community rich in Bacteroidetes colonized the interior of kelp tissues. Microbial cell density increased markedly along the length of the kelp blade, from sparse microbial colonization of newly produced tissues at the meristematic base of the blade to an abundant microbial biofilm on older tissues at the blade tip. Kelp from a declining population hosted fewer microbial cells compared to kelp from a stable population. Conclusions: Imaging revealed close association, at micrometer scales, of different microbial taxa with one another and with the host. This spatial organization creates the conditions necessary for metabolic exchange among microbes and between host and microbiota, such as provisioning of organic carbon to the microbiota and impacts of microbial nitrogen metabolisms on host kelp. The biofilm coating the surface of the kelp blade is well-positioned to mediate interactions between the host and surrounding organisms and to modulate the chemistry of the surrounding water column. The high density of microbial cells on kelp blades (10(5)-10(7) cells/cm(2)), combined with the immense surface area of kelp forests, indicates that biogeochemical functions of the kelp microbiome may play an important role in coastal ecosystems

Carbon and nitrogen isotopic ratios of urine and faeces as novel nutritional biomarkers of meat and fish intake

Purpose Meat and fish consumption are associated with changes in the risk of chronic diseases. Intake is mainly assessed using self-reporting, as no true quantitative nutritional biomarker is available. The measurement of plasma fatty acids, often used as an alternative, is expensive and time-consuming. As meat and fish differ in their stable isotope ratios, δ13C and δ15N have been proposed as biomarkers. However, they have never been investigated in controlled human dietary intervention studies. Objective In a short-term feeding study, we investigated the suitability of δ13C and δ15N in blood, urine and faeces as biomarkers of meat and fish intake. Methods The dietary intervention study (n = 14) followed a randomised cross-over design with three eight-day dietary periods (meat, fish and half-meat–half-fish). In addition, 4 participants completed a vegetarian control period. At the end of each period, 24-h urine, fasting venous blood and faeces were collected and their δ13C and δ15N analysed. Results There was a significant difference between diets in isotope ratios in faeces and urine samples, but not in blood samples (Kruskal–Wallis test, p < 0.0001). In pairwise comparisons, δ13C and δ15N were significantly higher in urine and faecal samples following a fish diet when compared with all other diets, and significantly lower following a vegetarian diet. There was no significant difference in isotope ratio between meat and half-meat–half-fish diets for blood, urine or faecal samples. Conclusions The results of this study show that urinary and faecal δ13C and δ15N are suitable candidate biomarkers for short-term meat and fish intake