Measurements of plasma colloid osmotic pressure, total protein and sodium concentration during haemodialysis: can single-pool sodium modelling explain the results?

Considering the plasma colloid osmotic pressure (COP) as a possible parameter for the monitoring of dialysis treatment compatibility, a characteristic time course was found. The COP and the total protein concentration very often do not increase significantly during the first treatment hour in spite of ultrafiltration. An increase in the plasma sodium concentration, which was higher than expected, was found to be the reason for a plasma dilution effect. This can be explained by a transcapillary sodium transfer coefficient which is not infinitely high as assumed in single-pool sodium modelling. From a 2-pool model considering the plasma volume as a separate pool and including capillary filtration time courses for plasma sodium, total protein concentration and COP could be calculated, which was very similar to the measured curves.

Comparison of atracurium, pipecuronium, and vecuronium for tracheal intubation.

In order to compare tracheal intubation conditions, 34 adult patients about to undergo elective surgery received at random atracurium 0.5 mg X kg-1, pipecuronium 0.1 mg X kg-1 or vecuronium 0.1 mg X kg-1, intravenously. Intubation was attempted when only the first of the train-of-four finger contractions, arising from ulnar nerve stimulation, remained. The three relaxants provided effective conditions for intubation. The time required to suppress all but the first train-of-four response was shortest in the group given atracurium (P less than 0.05). Compound muscle action potentials (emg) were continuously filmed from just before induction of anesthesia until the trachea was intubated. The degree of neuromuscular blockade was similar in the three study groups.

The link between chemoreceptor activity and voluntary salt intake in spontaneously hypertensive rats: a hypothesis.

The effect of normobaric hyperoxia on voluntary salt intake was investigated in conscious male SHR (n = 16). The animals were housed individually in metabolic cages and given free access to food, water and 2.5% NaCl-solution. The exposure of the rats to 40% oxygen in nitrogen for four days resulted in a significant enhancement of the salt intake. The present experiment further clarifies the relationship between chemoreceptor activity and salt intake. Hypobaric hypoxia as well as the pharmacological substance almitrine, both stimuli of the carotid bodies, decrease the voluntary salt intake in SHR significantly, whereas hyperoxia, characterized by lowering of the chemoreceptor activity, increases the salt intake. Our studies support the hypothesis that chemoreceptor activity has a modulating influence on salt appetite in SHR.