Prediction of cognitive dysfunction after resuscitation from out-of-hospital cardiac arrest using serum neuron-specific enolase and protein S-100.

BACKGROUND: More than 50% of patients initially resuscitated from out-of-hospital cardiac arrest die in hospital. OBJECTIVE: To investigate the prognostic value of serum protein S-100 and neuron-specific enolase (NSE) concentrations for predicting (a) memory impairment at discharge; (b) in-hospital death, after resuscitation from out-of-hospital cardiac arrest. METHODS: In a prospective study of 143 consecutive survivors of out-of-hospital cardiac arrest, serum samples were obtained within 12, 24-48 and 72-96 hours after the event. S-100 and NSE concentrations were measured. Pre-discharge cognitive assessment of patients (n = 49) was obtained by the Rivermead Behavioural Memory Test (RBMT). The relationship between biochemical brain marker concentrations and RBMT scores, and between marker concentrations and the risk of in-hospital death was examined. RESULTS: A moderate negative relationship was found between S-100 concentration and memory test score, at all time points. The relationship between NSE and memory test scores was weaker. An S-100 concentration >0.29 microg/l at time B predicted moderate to severe memory impairment with absolute specificity (42.8% sensitivity). S-100 remained an independent predictor of memory function after adjustment for clinical variables and cardiac arrest timing indices. NSE and S-100 concentrations were greater in patients who died than in those who survived, at all time points. Both NSE and S-100 remained predictors of in-hospital death after adjustment for clinical variables and cardiac arrest timing indices. The threshold concentrations yielding 100% specificity for in-hospital death were S-100: 1.20 microg/l (sensitivity 44.8%); NSE 71.0 microg/l (sensitivity 14.0%). CONCLUSIONS: Estimation of serum S-100 concentration after out-of-hospital cardiac arrest can be used to identify patients at risk of significant cognitive impairment at discharge. Serum S-100 and NSE concentrations measured 24-48 hours after cardiac arrest provide useful additional information.

Diurnal, week-to-week, and long-term variation in urine deoxypyridinoline cross-link excretion in healthy older women.

OBJECTIVES: To establish a reference range for morning and afternoon excretion of urinary deoxypyridinoline (DPD) in apparently healthy older women selected from a volunteer database. To assess the extent of diurnal variation and short and long-term within-subject longitudinal variation. DESIGN: Prospective, observational, cohort study. SETTING: Clinical Age Research Unit, King's College School of Medicine, London, United Kingdom. PARTICIPANTS: Forty-two women aged 68 to 89 (median age 75) selected from a volunteer database. METHODS: Subjects completed an osteoporosis risk factor questionnaire and a physical examination and had a measurement of the broadband ultrasound attenuation and speed of sound of their right heel. Subjects provided six urine samples: morning and afternoon at baseline and 1 week and 60 weeks later for measurement of DPD. RESULTS: The mean baseline values for DPD of morning and afternoon samples were 7.2 nM/mM and 6.0 nM/mM creatinine, respectively. The majority of subjects showed diurnal variation, with mean afternoon values 15% lower than morning values (P <.0001 for afternoon vs morning values). The mean difference in DPD after 60 weeks was 1.67 nM/mM for morning and 1.34 nM/mM for afternoon creatinine. This difference was not significant. Some individuals displayed marked changes in DPD excretion with no change in health status or treatment. DPD excretion in a nonfasting afternoon sample showed similar characteristics to morning void samples in terms of scatter, week-to-week variation, and long-term reproducibility. CONCLUSIONS: The study was set up to provide background data to assist the development of a clinical osteoporosis service for older women. Further studies are needed to determine whether these measurements predict fracture risk and respond to treatment changes in this age group.