Defining sepsis on the wards: results of a multi-centre point-prevalence study comparing two sepsis definitions.

Our aim was to prospectively determine the predictive capabilities of SEPSIS-1 and SEPSIS-3 definitions in the emergency departments and general wards. Patients with National Early Warning Score (NEWS) of 3 or above and suspected or proven infection were enrolled over a 24-h period in 13 Welsh hospitals. The primary outcome measure was mortality within 30 days. Out of the 5422 patients screened, 431 fulfilled inclusion criteria and 380 (88%) were recruited. Using the SEPSIS-1 definition, 212 patients had sepsis. When using the SEPSIS-3 definitions with Sequential Organ Failure Assessment (SOFA) score ≥ 2, there were 272 septic patients, whereas with quickSOFA score ≥ 2, 50 patients were identified. For the prediction of primary outcome, SEPSIS-1 criteria had a sensitivity (95%CI) of 65% (54-75%) and specificity of 47% (41-53%); SEPSIS-3 criteria had a sensitivity of 86% (76-92%) and specificity of 32% (27-38%). SEPSIS-3 and SEPSIS-1 definitions were associated with a hazard ratio (95%CI) 2.7 (1.5-5.6) and 1.6 (1.3-2.5), respectively. Scoring system discrimination evaluated by receiver operating characteristic curves was highest for Sequential Organ Failure Assessment score (0.69 (95%CI 0.63-0.76)), followed by NEWS (0.58 (0.51-0.66)) (p < 0.001). Systemic inflammatory response syndrome criteria (0.55 (0.49-0.61)) and quickSOFA score (0.56 (0.49-0.64)) could not predict outcome. The SEPSIS-3 definition identified patients with the highest risk. Sequential Organ Failure Assessment score and NEWS were better predictors of poor outcome. The Sequential Organ Failure Assessment score appeared to be the best tool for identifying patients with high risk of death and sepsis-induced organ dysfunction.

Stereochemistry of the human macular carotenoids.

PURPOSE: To complete identification of the major components of the human macular pigment. METHODS: Chemical ionization mass spectra of the macular pigment components were obtained and compared with those of zeaxanthin and lutein standards. A comparison was also made using chiral column high-performance liquid chromatography, which is capable of resolving individual stereoisomers of these carotenoids. Zeaxanthin and lutein from human blood plasma were similarly analyzed. RESULTS: The mass spectrometry data supported earlier work in which high-performance liquid chromatography, UV-visible spectrometry and chemical modification showed that the macular pigment comprises two carotenoids with identical properties to those of zeaxanthin and lutein. Chiral column chromatography showed that the "zeaxanthin" fraction is a mixture of two stereoisomers, zeaxanthin itself [(3R,3'R)-beta,beta-Carotene-3,3'-diol] and meso-zeaxanthin [(3R,3'S)-beta,beta-Carotene-3,3'-diol]. The other fraction is the single stereoisomer, lutein [(3R,3'R,6'R)-beta,epsilon-Carotene-3,3'-diol]. In human blood plasma, only zeaxanthin and lutein were found. CONCLUSIONS: The results strongly suggest that meso-zeaxanthin results from chemical processes within the retina. Noting that lutein exceeds zeaxanthin in plasma but that the combined zeaxanthin stereoisomers exceed lutein in the retina, the possibility was considered that meso-zeaxanthin is a conversion product derived from retinal lutein. Under nonphysiologic conditions, the authors demonstrate that a base-catalyzed conversion of lutein to zeaxanthin yields only the meso-(3R,3'S) stereoisomer.

Optical density spectra of the macular pigment in vivo and in vitro.

A precise relative optical density spectrum of the macular pigment, based upon its dichroic properties, was determined. The spectrum proved essentially identical to that of liposome-bound zeaxanthin and lutein, a system duplicating the macular pigment and its environment. Substantial agreement was also found with the spectra of Wyszecki and Stiles (1982, Color science: Concepts and methods, quantitative data and formulae. New York: Wiley) and Vos (1972, Institute for Perception, RVO-TNO, IZF 1972-17, Soesterberg, The Netherlands), and the latter is recommended as a standard. For 7 subjects, the pigment density spectrum derived from foveal and extra-foveal sensitivities was compared with the dichroism-based spectrum. Results indicated that the pigment is described by a common distribution of molecular orientations for all subjects.