Azotaemia in severe head injury--central dysregulation or renal failure?

Differential pulse voltammetry in vivo with working carbon fiber electrodes: 5-hydroxyindole compounds or uric acid detection?

Differential pulse voltammetry was performed in rats chronically implanted with carbon fiber electrodes in the caudate (n.Cd) and raphe dorsalis (n.RD) nuclei. The electrochemical signal obtained at the +300 mV potential (peak 3) in animals implanted for more than one week (long term chronic conditions, greater than 7 days) could be dependent upon the extracellular fraction of 5-hydroxyindolacetic acid (5-HIAA) since a single injection of Pargyline is sufficient to suppress it in n.Cd and n.RD. This result was obtained despite the tendency of Pargyline to increase n.Cd and n.RD endogenous concentrations of Uric Acid (UA) measured by High Performance Liquid Chromatography (HPLC). In contrast, in animals implanted for less than one week (short term chronic conditions, less than 7 days) peak 3 recorded in the same structure could be dependent upon extracellular fractions of 5-HIAA and UA since consecutive injections of Pargyline and Allopurinol are necessary to suppress this signal. The source of extracellular UA measured in brain by voltammetry, in such short term chronic conditions, might result from surgical trauma.

Predicting lethal outcome after severe head injury -- a computer-assisted analysis of neurological symptoms and laboratory values

A total number of 58 parameters (laboratory values, neurological symptoms, and vegetative parameters) were evaluated in 150 patients during the first seven days after severe head injury. The patients were divided into two groups, "survivors" and "non-survivors". Eight easily evaluable routine parameters with the most significant differences between the two groups of patients were used for statistical evaluation of a "no survival chance score". These highly indicative parameters are serum osmolarity and urea, blood glucose, total bilirubin, motor reaction to stimuli, body temperature, respiratory activity, and pupil reaction. A "low survival chance limit" was evaluated from each of these parameters by computer analysis. None of the patients in the series survived when three or more of these eight parameters had climbed beyond the limit. So far, the system is able to predict "no survival chances" in 50.8% of the non-survivors some six days prior to death; 80% of these predictions could be made by the fourth day after injury.