Fluid and Electrolyte Balance

KNH 413

Body SolutesTypes of solutes

Electrolytes 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

Body SolutesDistribution 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 sizeElectrical charge of the moleculeHydrostatic pressure (pressure exerted by fluid due to

the force of gravity)Method of solute transport (what’s going on with the

proteins?)

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 SystemRAAS

Disorders of Fluid BalanceAlterations 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)

Disorders of Fluid Balance

Calcium imbalanceHypocalcemiaHypercalcemia

Phosphorus imbalance (looking at a status of energy deficiency and acid/base balance)HypophosphatemiaHyperphosphatemia

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

© 2007 Thomson - Wadsworth

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 woundNutrient restriction: cardiovascular disease, renal

diseaseOral intake: inadequate amount Intake vs. output: concern with geriatric population