The minimum discard volume: accurate analysis of peripheral hematocrit.

The purpose of this research is to quantify the minimum amount of blood that must be discarded from an indwelling peripheral intravenous catheter (deadspace 0.5 ml) to obtain an accurate hematocrit reading. Repeat blood sampling from nine subjects is used to develop a mathematical model (Michaelis-Menten curve) describing the mixing of the flush solution and the blood. This model is used to estimate the hematocrit when different volumes are discarded. Differences between the computed hematocrit and true hematocrit were determined for each subject. When 1.5 ml (three times the deadspace volume) is discarded, the 95% confidence interval is within 0.6% of the true hematocrit.

Generational boundary dissolution between mothers and their preschool children: a relationship systems approach.

A particular perspective on relationship systems served as the basis for this research. Postulates within this perspective include qualitative aspects of relationships are stable over time, and there are lawful relations among relationships within the same system. Previously, a concept of seductive mother-toddler relationships was initially validated. From the theory surrounding this concept, later forms of this pattern were conceived, and a hypothesis concerning complementary mother-daughter relationships was formulated. In the present research we showed first that the pattern of "seductiveness" was stable, though transformed, from 24 to 42 months. Second, the same mothers were not found to be seductive with male or female siblings. Third, mothers who showed the seductive pattern (almost always with boys) were, as predicted, hostile toward their daughters in a particular way ("derision"). 2 other scales used at 42 months ("nonresponsive intimacy" and "generational boundaries") were elevated for target mother-male dyads and not for mother-daughter pairs. In fact, mothers who were seductive with sons were rated significantly lower on the intimacy scale when seen with daughters than were control mothers. It is suggested that maternal relationships across siblings are coherent, however distinct, and that these connections derive from the totality of the mother's relationship history.