Final answer:
Calcium management prior to separation from bypass involves understanding the body's mechanisms for regulating calcium and phosphorus balance, particularly in the context of age-related changes and menopause. Estrogen and androgen can correct negative balances, whereas in hypercalcaemia, the kidney threshold becomes abnormal, altering excretion patterns.
Step-by-step explanation:
Management of Calcium Levels in Bypass Patients
Calcium homeostasis is a critical aspect of managing patients who are about to be separated from cardiac bypass. The body naturally regulates calcium levels through various mechanisms. After the age of about 55 to 60, there is a diminishing capacity for intestinal transport of calcium, which can lead to a negative calcium-phosphorus balance and potentially, osteoporosis, particularly during menopause in women. Both estrogen and androgens, such as testosterone, can help improve this balance, with a combination of the two proving more effective.
In hypercalcaemia conditions where there is an excessive amount of calcium in the blood, the kidney threshold for calcium becomes abnormal. Under normal circumstances, any extra calcium absorbed from the intestine is excreted in the urine. The body excretes calcium through urine, bile, and digestive secretions, with approximately 75% of dietary calcium being absorbed and the remainder excreted. Of the calcium filtered by the renal glomeruli, a fraction is excreted in the urine, with most being reabsorbed. Factors such as rigorous physical exercise can increase calcium loss through sweat.