N105: Essentials of Nursing Care - Health Differences

Essentials of Nursing Study Guide

©2017 Achieve Test Prep Page 91 of 160 4.5 Common Diseases Hypernatremia is most often the cause of too little fluid, as seen with dehydration and too much sodium. In dehydration, you will see elevated hematocrit, serum chloride greater than 106 mEq/L, and urine specific gravity greater than 1.025. Treatment in most cases is focused on giving fluid, not removing sodium. Hypernatremia can also be caused by insufficient secretion of ADH (diabetes insipidus), insensible water loss (severe burns), hypertonic enteral feedings, potassium depletion from vomiting, diarrhea, nasogastric suctioning, uncontrolled diabetes mellitus, excessive administration of osmotic diuretics or sodium bicarbonate, and renal failure. Increased sodium causes hypertonicity of the serum. This causes a shift of water out of the cells making the cells dehydrated. It is a difficult electrolyte imbalance to treat as too rapid correction of the sodium level may cause serious cerebral edema. loss. Renal and cardiac function, medications, and dehydration (hyperosmolar imbalance) all will cause loss of water without significant loss of electrolytes. Disturbances in Fluid Volume, Electrolyte, and Acid-Base Balances • Fluid volume deficit: This occurs when equal amounts of fluid and electrolytes from the extracellular fluid are lost (hypovolemia). Decreased fluid intake, bleeding, or movement of fluid into a third space will also case fluid volume deficit. • Third space syndrome: This causes fluid to remain in the body but is essentially unavailable for use. This fluidmay be sequestered in the bowel, interstitial space as edema, inflamed tissue, or in the peritoneal or pleural cavities. • Fluid volume excess: This occurs when both water and sodium are retained and serum sodium remains normal (hypervolemia). Excessive intake of salt, infusions containing sodium given too rapidly, and impaired regulatory mechanisms can cause congestive heart failure, renal failure, cirrhosis of the liver, and Cushing’s syndrome. • Edema: This is excess interstitial fluid. Edema is most apparent around the eyes and dependent tissues such as the feet, ankles, and sacrum. Malnutrition and liver or kidney diseases can reduce oncotic pressure and prevent fluid from being drawn into the capillaries. Pitting edema leaves a small depression or pit after finger pressure is applied to the swollen area. • Dehydration: This is a loss of water only retaining sodium and increasing serum sodium levels. Older adults are at risk because of decreased thirst sensation. This can be caused by hyperventilation, prolonged fever, diabetic ketoacidosis, and enteral feeding with insufficient water intake. • Over-hydration: This is water intoxication (hypo-osmolar imbalance). Water is gained in excess of electrolytes, low serum osmolality, and decreased serum sodium levels. Water is drawn into the cells, causing swelling. Cerebral edema and impaired neurologic function can happen in the brain. This can occur after excessive sweating when only water is replaced and may also result from SIADH.