PLASMA POTASSIUM RHYTHMS IN NORMOKALEMIA AND HYPOKALEMIA: ESTABLISHING THE PHYSIOLOGICAL BASIS FOR NURSING INTERVENTIONS.
Contributors: University of Washington.
Published: 1986
Number of pages: 247
Subjects: Health Sciences, Nursing.
Description: Although much nursing research has examined the effectiveness of specific nursing measures, little attention has been directed toward the optimum timing of nursing therapies. This study provides the physiological basis for examination of the possible benefits of timing nursing measures with the 24-hour rhythms of plasma electrolytes. The purpose of this study was to describe the 24-hour variation of plasma potassium, sodium, magnesium, corticosterone, and aldosterone in normokalemic and hypokalemic rats and to describe the relationships between these variables.

Male Sprague-Dawley rats (n = 96) weighing 75-100 g. were kept on a controlled lighting schedule (12 hours light, 12 hours dark). Half the rats were fed standard diet; half were fed potassium-restricted diet. After 4 weeks, eight rats from each group were sacrificed every 4 hours for 24 hours. Plasma potassium and sodium were measured with ion-selective electrodes; plasma magnesium was determined by atomic absorption spectrophotometry. Plasma corticosterone and aldosterone were determined by radioimmunoassay. Peak and trough values were compared with Wilcoxon rank sum tests. Symmetrical rhythms without secondary peaks were analyzed with cosinor analysis.

Significant rhythms of plasma potassium, sodium, magnesium, and aldosterone were demonstrated in both the normokalemic and hypokalemic rats. The plasma potassium and aldosterone rhythms in the hypokalemic rats exhibited a 4 hour eariler time course than in the normokalemic rats. The plasma sodium rhythm had an earlier peak in the hypokalemic rats but the troughs occurred at the same time in the two groups. The plasma magnesium rhythms in the two groups of rats had no major time or waveform differences.

This study is the first known plasma electrolyte and hormone rhythm research in the hypokalemic state. It delineates the physiological basis for investigating the timing of nursing therapies, such as the timing of oral potassium supplementation or replacement, with the 24-hour variation of plasma electrolytes. In summary, it provides the physiological foundation on which to study the timing, as well as the effectiveness, of nursing therapies that affect electrolyte homeostasis.
Notes: Source: Dissertation Abstracts International, Volume: 47-12, Section: B, page: 4823.

Thesis (PH.D.)--UNIVERSITY OF WASHINGTON, 1986.

School code: 0250.