FLUID, ELECTROLYTE, AND ACID-BASE BALANCE NUR 102 - Chapter 14

Body fluids Extracellular fluids (ECF) Interstitial fluid - fills the spaces between most cells of the body Intravascular fluid - plasma (WBC, RBC and platelets in this fluid) Interstitial fluid is 15% of body weight Intravascular fluid is 5% of body weight

Body fluids Intracellular fluids (ICF) Liquids within cell membranes 40% of body weight Intracellular – 40% of body weight

Components in body fluids Electrolyte an element that when dissolved can carry an electrical current Cations - (+) ; Anions - (-) neuromuscular function acid-base balance Cations – positively charged Anions – negatively charged

Components of body fluids Minerals ingested compounds serve as catalysts in nerve response, muscle contraction, and metabolism of nutrients in foods, regulate electrolyte balance

Movement of body fluids Diffusion Area of higher concentration to an area of lower concentration till even distribution Osmosis Movement of a pure solvent, e.g. water through a semipermeable membrane from a solution that has a lower solute concentration to one that has a higher solute concentration

Osmotic pressure Drawing power of water (dependent on the number or molecules in solution) Isotonic Hypotonic Hypertonic Isotonic - Solution with same osmolality as blood plasma Hypotonic - Lesser concentration than blood plasma Hypertonic - Greater concentration than blood plasma

Movement of body fluids Filtration Water and diffusible substances move together in response to fluid pressure Active transport Requires energy Able to move larger molecules and go from less to greater concentration

Fluid Intake Hypothalamus - thirst control center Oral fluid intake requires an alert state Osmoreceptors - monitor osmolality

Fluid Output Loss through the kidneys and GI tract Insensible Sensible not perceived by the person Sensible perceived by the person occurs through excessive perspiration

Cations Sodium (Na+) Most abundant in the extracellular fluid Maintains water balance, transmits nerve impulses, contracts muscles Values - 135-145 mEq/L Found in processes meats, snacks, canned foods, and table salt

Cation Potassium (K+) Major intracellular cation Regulates neuromuscular excitability, muscular contraction, and acid-base Value - 3.5 -5.3 mEq/L Found in whole grains, fruits, and vegetables

Cation Calcium (Ca2+) Cardiac conduction, blood coagulation, bone growth and formation, & muscular relaxation Value - 4 - 5 mEq/L Found in dairy products

Cation Magnesium (Mg2+) Second most important of intracellular fluids Enzyme activities, muscular excitability Value - 1.5 - 2.5 mEq/L

Electrolyte Imbalances Hyponatremia GI losses, sweating, & diuretics S/S: N/V/D, abd cramps, personality change Hypernatremia Ingestion of large amounts S/S: Dry tongue and mucous membranes, restlessness, convulsions, thirst, dry skin

Electrolyte imbalances Hypokalemia Causes: K+ wasting diuretics N/V/D polyuria S/S: weak, irregular pulse hypotension weakness

Electrolyte imbalances Hyperkalemia Causes: Renal failure S/S: irregular slow pulse, weakness, irritability

Electrolyte Imbalances Hypocalcemia Causes: Vitamin D deficiency S/S: Numb and tingling fingers and circumoral region, muscle cramps Hypercalcemia Causes: osteoporosis, prolonged immobilization S/S: decreased muscle tone, weakness, lethargy, kidney stones

Electrolyte imbalances Hypomagnesemia Causes: malnutrition and alcoholism polyuria S/S: muscular tremors, hyperactive deep tendon reflexes Hypermagnesemia Causes: Renal failure S/S: hypoactive deep tendon reflexes, shallow and slow respirations

Acid - Base Balance Blood pH - 7.35 - 7.45 paCO2 - 35 - 45 Bicarbonate (HCO3) - 22-26 mEq/L

Respiratory Acidosis pH < 7.35 paCO2 > 45 mm Hg Causes: Respiratory failure Hypoventilation Resp muscles paralysis Airway obstruction

Respiratory Alkalosis pH > 7.45 paCO2 < 35 mm Hg Causes: excessive exhalation of CO2 (hyperventilation)

Metabolic Acidosis pH < 7.35 bicarbonate - < 22 mEq/L Causes: Starvation, DKA, Diarrhea, drug use

Metabolic Alkalosis pH > 7.45 bicarbonate > 26 mEq/L Causes: excessive vomiting, prolonged gastric suctioning

Fluid & Electrolyte Imbalances Burns - body fluid loss Renal D/O - abnormal retention of Na, Cl, K GI Disturbances - Loss of fluid, potassium, and chloride Exercise

S/S electrolyte imbalance Head: irritability Fontanels: depressed, bulging Eyes: sunken periorbital edema Mouth: mucous membranes CV: neck veins, edema, blood pressure Resp: Crackles

Imbalances GI: abdomen, V/D Renal: Oliguria or anuria (FVD, FE) Diuresis (FVE) Increased urine spec. gravity (FVD) Skin (Temp) increased - met acidosis, hypernatremia decreased - FVD

Replacement of fluids and electrolytes Types of IV fluids Isotonic Hypertonic Hypotonic

IV complications Infiltration Phlebitis Fluid overload Bleeding IVF enter SQ space Phlebitis vein inflammation S/S: pain, redness, warmth Fluid overload Fluids given too rapidly Bleeding

Discontinuing an IV Stop infusion Remove tape 1 - 2 minute pressure

Blood transfusions Large bore catheter (18 ga or larger) Give with normal saline Baseline vital signs Double check with two RNs Begin transfusion slowly Observe closely for first 15 min

Transfusion Reactions Caused by: blood incompatibility allergic sensitivity S/S: fever, chills, rash, hypotension, shock Treatment: stop transfusion, give NS, save tubing, prepare for emergency drugs