Fluid, Electrolyte & Acid- Base Balance

Body Fluids Your body is 66% water Not evenly distributed – separated into compartments. Able to move back and forth thru the cell membranes to maintain an equilibrium

Functions of Water in the Body Transporting nutrients to cells and wastes from cells Transporting hormones, enzymes, blood platelets, and red and white blood cells Facilitating cellular metabolism and proper cellular chemical functioning Acting as a solvent for electrolytes and nonelectrolytes Helping maintain normal body temperature Facilitating digestion and promoting elimination Acting as a tissue lubricant reduce friction

Fluid Compartments Intracellular fluid – fluid inside cells [ICF] Extracellular fluid – fluid outside cells and all other body fluids --- ¼ is plasma [intravascular fluid], remaining ¾ is interstitial fluid (tissue). Small amount is localized as Cerebrospinal fluid, serous fluid, synovial fluid, humors of eye & endo/perilymph of ears.

Two Compartments of Fluid in the Body Intracellular fluid (ICF) — fluid within cells (70%) Extracellular fluid (ECF) — fluid outside cells (30%) Includes intravascular and interstitial fluids

Variations in Fluid Content Healthy person — total body water is 50% to 60% of body weight An infant has considerably more body fluid and Extracellular fluid than an adult Sex and amount of fat cells affect body water Women and obese people have less body water

Edema Edema results whenever small blood vessels become "leaky" and release fluid into nearby tissues. The extra fluid accumulates in the interstitial compartment, causing the tissue to swell. Sometimes due to blockage of lymphatic vessels or by a lack of plasma proteins or sodium retention.

Fluid Balance Amount in = amount out Average daily intake is 2500 ml [ fluids, food and metabolic water] Average daily output is 2500 ml [ urine, feces, perspiration, insensible perspiration] What can throw off these numbers?

Electrolyte Balance Def: - Electrolytes are minerals in the body that have an electric charge. They are in blood, urine and body fluids. Maintaining the right balance of electrolytes helps your body's blood chemistry, muscle action and other processes. Sodium, calcium, potassium, chlorine, phosphate and magnesium are all electrolytes.

Fluid Balance Solvents — liquids that hold a substance in solution (water) Solutes — substances dissolved in a solution (electrolytes and non- electrolytes)

COMMON ELECTROLYTES Sodium (Na ++ ) Functions  Regulates volume of body fluids  Maintains water balance  Regulates ECF  Influences ICF  Generation and transmission of nerve impulses  Sodium-Potassium pump

Electrolyte Balance Potassium (K + ) is the predominant intracellular cation and phosphates are the predominant intracellular anion Cations are actively reabsorbed, anions passively follow by electrochemical attraction Aldosterone (steroid hormone) works at kidney tubules to regulate sodium & potassium levels

POTASSIUM (K + ) Major cation in ICF Reciprocal to sodium Functions Regulates cellular enzyme activity and water content Transmission of nerve and muscle impulses Metabolism of proteins and carbohydrates Regulation of acid-base balance by cellular exchange with H +

CALCIUM (Ca ++ ) Most abundant electrolyte in body 99% found in bones and teeth Functions Nerve impulse transmission and blood clotting Catalyst for muscle contraction Thickness and strength of cell membranes

MAGNESIUM (Mg ++ ) Second most important cation in ICF Functions Metabolism of carbohydrates and proteins Vital enzyme actions Protein and DNA synthesis Maintaining intracellular levels of Potassium Maintain electrical activity in nervous tissue and muscle tissue membranes

OTHER ELECTROLYTES Sulfate Anion ICF Excreted in the kidney Lactic acid Anion Facilitates diffusion to and from capillaries

Electrolyte Balance Because of sodium and potassium influence, water will move between compartments Example: if high [sodium], then water will move from intracellular space to extracellular space due to osmotic pressure

Acid - Base Balance Blood - normal pH of 7.2 – = alkalosis 3 buffer systems to maintain normal blood pH 1. Buffers 2. Removal of CO 2 by lungs 3. Removal of H + ions by kidneys

Buffers Protein Buffer Systems help maintain acidity in and around the cells.  Amino Acid buffers  Hemoglobin buffers  Plasma Protein buffers Phosphate Buffer Systems Carbonic Acid – Bicarbonate Buffer System

Maintenance of Acid-Base Balance Respiratory System: removal of CO 2 by lungs – stabilizes the ECF, has direct effect on Carbonic Acid – Bicarbonate Buffer System Urinary System: removal of H + ions by kidneys

Fluid Imbalances Involves either volume or distribution of water or electrolytes Hypovolemia — deficiency in amount of water and electrolytes in ECF with near normal water/electrolyte proportions Dehydration — decreased volume of water and electrolyte change Third-space fluid shift — distributional shift of body fluids into potential body spaces

Lab Studies to Assess for Imbalances Complete blood count Serum electrolytes Urine pH and specific gravity Arterial blood gases

Administering Medications Mineral-electrolyte preparations Diuretics which promotes the production of urine Intravenous therapy

Quiz #1 For the patient with hyperkalemia ( high potassium) related to decreased renal excretion secondary to potassium conserving diuretic therapy” an appropriate expected outcome would be which of the following? a) Bowel motility will be restored within 24 hours after beginning supplemental K+ b) ECG will show no cardiac arrhythmias within 48 hours after removing salt substitutes, coffee, tea and other K+ rich foods from the diet c) ECG will show no cardiac arrhythmias within 24 hours after beginning supplemental K+ d) Bowel motility will be restored within 24 hours after eliminating salt substitutes, coffee, tea, and other K+ rich foods from the diet

#2 Which of the following nursing diagnoses would you expect to find based on the effects of fluid and electrolyte imbalance on human functioning? a) Constipation related to immobility b) Pain related to surgical incision c) Altered thought processes related to cerebral edema, including mental confusion and disorientation d) Health risk for infection related to inadequate personal hygiene

#3 A nurse who diagnoses a patient as having “fluid volume excess” related to compromised regulatory mechanisms (kidneys) may have been alerted by which of the following symptoms? a) Muscular twitching b) Distended neck veins c) Fingerprinting over sternum d) Nausea and vomiting

KEY 1-B 2-C 3-B