N105: Essentials of Nursing Care - Health Differences

Essentials of Nursing Study Guide

©2017 Achieve Test Prep Page 89 of 160 • Calcium: One percent of skeletal calcium is rapidly exchangeable with blood calcium. With age the intestines absorb calcium less effectively and more is excreted, leading to the risk of osteoporosis and fractures. The rest exchanges more slowly. Normal serum calcium is 8.5-10.5 mg/dL. Dairy products are the best source of calcium but it can be found in dark green leafy vegetables and canned salmon. Calcium has a reciprocal relationship with phosphate. Increasing serum calcium levels decreases phosphate levels. • Magnesium : This is the second most abundant intracellular cation. Magnesium is important in carbohydrate and protein metabolism. It is also important in protein and DNA synthesis within the cells. Balance is important in neuromuscular function. Good sources of magnesium are dried fruit, legumes, green leafy vegetables, dairy products, meat, and fish. • Chloride (Cl-): Chloride is a major anion of extracellular fluid. Chloride is regulated secondarily to sodium. When sodium is reabsorbed in the kidney, chloride usually follows. • Phosphate (PO-): Phosphate is essential for function of muscles, nerves, and red blood cells. Phosphate is involved in the metabolism of protein, fat, and carbohydrates. Good sources of phosphate are meat, fish, poultry, milk products, and legumes. • Bicarbonate (HCO-): This is used in regulating acid-base balance. Kidneys both regenerate and reabsorb bicarbonate ions. Adequate amounts of bicarbonate are produced through metabolic processes to meet the body’s needs. Normal Range Cause of Elevation Causes of Decline Sodium (Na): 135-145 mEq/L Hypernatremia: Excessive loss of water through GI system, lungs, or skin; fluid restriction; certain diuretics; hypertonic IV solutions; tube feeding; hypothalamic lesions; hyperaldosteronism; corticosteroid use; Cushing’s syndrome; diabetes insipidus Hyponatremia: Congestive heart failure; cirrhosis; nephrosis; excess fluid intake; syndrome of inappropriate antidiuretic hormone secretion (dilutional hyponatremia); sodium depletion; loss of body fluids without replacement; diuretic therapy; laxatives; nasogastric suctioning; hyperaldosteronism; cerebral salt- wasting disease Potassium (K): 3.5-5.0 mEq/L Hyperkalemia: Aldosterone deficiency; sodium depletion; acidosis; trauma; hemolysis of red blood cells; potassium-sparing diuretics Hypokalemia: Lack of dietary intake of potassium; vomiting; nasogastric suctioning; potassium- depleting diuretics; aldosteronism; salt-wasting kidney disease; major GI surgery; diuretic therapy with inadequate potassium replacement