Fluid and Electrolyte Balance KNH 413 Maintaining homeostasis: 1. water/fluid balance, 2. electrolyte balance

Plasma: high % Na, l, Bicarb, Pro Interstitial: tissues Intracellular: % K, NaP 1400-1500 cc’s of fluid to maintain the balance between these 3 -Food sources: 700 cc’s of fluid (iceberg lettuce, fruits, etc) -Bi-product of processing/metabolism the food: 200 cc’s

Calculating fluid needs of an individual: per kilo 10 kg baby: 100-150 mL/kg= ~1,000 cc’s 30 cc’s per oz., meaning 33 oz of formula/day (divide by 8, so 4 oz per feeding) 40-60 for an adolescent because they’re probably more active whereas adults generally tend to be less active, so they have a lower fluid need

Body Solutes Types of solutes Electrolytes Other molecules Sodium, potassium, calcium, magnesium, chloride, bicarbonate, phosphate, sulphate Ions dissociate to form charged particles Other molecules Glucose, protein, urea, lactate, organic acids—keep these in a stable range! Hyperglycemic patient: excess sugar in the blood, where it is pulling fluids out, and fluid status would therefore not be balanced Remain stable Intracellular: K, Mg, P Extracellular: Na, Ca, Cl, Bicarb

Body Solutes Distribution of solutes Sum of cations (positive charge) must be equal to sum of anions (negative charge) within a given compartment Movement of solutes influenced/measured by: Molecular size Electrical charge of the molecule Hydrostatic pressure (pressure exerted by fluid due to the force of gravity) Method of solute transport (what’s going on with the proteins?) Fluid and acid/base balance: Maintaining fluid balance as removing waste between blood and tissue

Plasma: 5% water Interstitial: 15% water Intracellular: 40% water Total= 60% of water found in these areas Look at AI b/c no RDA Potassium: after 6 months, infants need 3,000 mg K per day (raisons, potatoes, beans, spinach, bananas) Adults need 4,500 g K per day Breastfeeding mothers need to maintain K for themselves and their infant, RD would need to work with the individual to see what they prefer as their high source of K. Supplement may be used, yet the concern would be K toxicity so levels would need to be closely monitored (perhaps half supplement during meal)

SHOULD JUST KNOW!

Regulation of Fluid and Electrolytes Osmotic and hydrostatic pressure—keep in balance Thirst—triggered by hypothalamus and increased with fluid intake (preventative hydration) Renal—increases amount of fluids running through the kidney Hormonal influence – RAAS (influencing kidneys to retain sodium and pull fluid back into the blood) Electrolyte regulation—want to keep all of these in balance

Regulation of Fluid and Electrolytes Thirst Renal function Renin-Angiotension-Aldosterone System RAAS

Glomerular Filtration Rate

High blood Ca, body inhibits vitamin D uptake Osteoporosis needs Ca regulation Levels who have high: Phosphate binders/regulating amount of Ca in diet Low blood calcium client: premature infant who’s kidneys aren’t fully developed

Disorders of Fluid Balance Alterations in volume Hypovolemia Hypervolemia Alterations in osmolality From electrolytes imbalances Sodium imbalances Hyponatremia Hypernatremia Potassium imbalances (looking at acid/base balance as well) Hypokalemia (look at albumin levels first) Concerns: bone abnormalities/blood clotting Hyperkalemia (look at renal status) For Na and K imbalances, look at the Composition of fluid/amount of Na or K in solution

Disorders of Fluid Balance Calcium imbalance Hypocalcemia Hypercalcemia Phosphorus imbalance (looking at a status of energy deficiency and acid/base balance) Hypophosphatemia Hyperphosphatemia Magnesium imbalance (looking at kidneys regulating this and bone) Hypomagnesemia (muscle weakness and tremors) Hypermagnesemia (muscle weakness)

Disorders of Fluid Balance What are the… Causes ? Kidney disfunction Clinical manifestations ? Edema/fluid overload Pitting edema: hyponatremia (sodium levels) Laboratory findings ? Treatment ? Identify underlying cause Might need to change the administration of: Na, K, Pro, Fluid

Rapid changes in weight Pulse/cardiac changes Osmolality © 2007 Thomson - Wadsworth

Rehydration: normal fluid osmolality: 300 mOsm/L (anything below this would be dehydrated)

Fluid and Electrolyte Balance Assess for factors that affect fluid and electrolyte balance: Disease or injury: burn patients, individuals who have sores in mouth or brain injury making it so they don’t physically consume enough, DKA Medication or treatment: medications (Lasics) that pull out Na or K Fluid loss: gun shot wound Nutrient restriction: cardiovascular disease, renal disease Oral intake: inadequate amount Intake vs. output: concern with geriatric population