N105: Essentials of Nursing Care - Health Differences

Essentials of Nursing Study Guide

©2017 Achieve Test Prep Page 88 of 160 4.4 Regulating Electrolytes • Sodium: Sodium is abundant in the extracellular fluid. Normal value is 135-145 mEq/L. Loss or gain of sodium is usually accompanied with a loss or gain of water. Sodium functions in establishing the electro-chemical state for muscle contraction and the transmission of nerve impulses. Sodium is not stored in the body and must be consumed daily. Foods that are high in sodium are bacon, ham, processed cheese and table salt. • Potassium: The normal value is 3.5 – 5.5 mEq/L and it is a major intracellular electrolyte. Potassium helps maintain intracellular fluid water balance. Ninety-eight percent of potassium is found inside the cell. The remaining 2% is in the extracellular fluid and is important in neuromuscular function. Potassium influences skeletal, cardiac, and smooth muscle activity. To maintain potassium balance, the renal system must function because 80% of potassium is excreted daily; the other 20% is lost through the bowel and sweat glands. Potassium rich foods include avocado, baked potato, spinach, meats, dates, raisins, banana, milk, and orange juice. diluted (via fluid overload, etc), it is going to want to get rid of some of the water to bring the plasma back to a normal state. Water is going to shift from the plasma into the cells. With regards to sodium, remember the following: too little sodium in the bloodstream (hyponatremia) will cause fluid to shift into the cells because the concentration (tonicity) is greater there. The body has a natural tendency to want both intracellular and extracellular fluids to have close to the same tonicity (tonicity being the concentration of solutes such as sodium, albumin, etc), so it will keep shifting fluids in an attempt to achieve this. Fluids shifting into the cells cause the cells to swell. Too much sodium in the blood (hypernatremia) will cause water to be pulled from the cells. Fluid shifts out of the cells and into the bloodstream in an attempt to balance things out. This causes the cells to shrink. The cells having fluid pulled from them can actually cause cellular dehydration, as sometimes the cells cannot afford the fluid loss. Conversely, it can be beneficial, as in the cause of increased intracranial pressure—pulling fluids from the cells shrink the cells and reduces the pressure. 4.3 Common IV Fluids • Isotonic: These fluids are the normal state, the balance fluids that do not tend to shift the fluids either into or out of the cells. They are D5W (5% dextrose in water), 0.9% NACL (Normal Saline, NSS), Ringer's Lactated, and Ringer's 5% dextrose with 0.2% NACL. • Hypotonic: These fluids cause a dilution of the plasma, hence having a tendency to push fluids into the cells. They are 0.45% NACL (half normal saline). • Hypertonic: These fluids increase the plasma tonicity in many cases, hence having a tendency to pull fluids from the cells. They tend to be used very carefully, often in intensive care situations, because of their ability to seriously throw fluids and electrolytes off. They are 10% (or above) dextrose in water, 3%NACL, 5% dextrose with 0.45% NACL, and 5% dextrose with 0.9% NACL.