Management of Fluid and Electrolyte Replacement

Hartnell College

Pharmacology NRN 130

Laurie Phillips RN, MSN, PHN

Homeostasis

• Tendency to maintain fluid in specific compartments

• Necessary for cells to carrying out their functions

• Process involves deliver of elements to the cell such as O2 and glucose and remove waste products such as CO2

• When not maintained, illness will occur

Body Fluid Compartments

• Intracellular (ICF) - Fluid within the cell. Most body fluid is found here.

• Extracellular (ECF) - fluid found outside the cell such as plasma/serum. Responsible for transport of nutrients and waste.– intravascular: fluid surrounding the cells– interstitial fluid: including lymph fluid– other: digestive secretions, CSF, sweat

Body Fluid Composition

• H2O– largest portion of body wt. that decreases

with age– women have a lower % of water storage

because of increased fat cells which do not contain as much H2O as other cells

– Affected by age, sex, and amount of body fat

Body Fluid Composition

• Solutes (electrolytes and nonelectrolytes)• Electrolytes - substance that contains an

electrical charge when dissolved in H2O; break into ions– Cations (NA+, Ca+, Mg+)– Anions (Cl-, HCO3-, HPO4-)

Body Fluid Composition

• Every fluid compartment contains a balance of cations and anions

• The concentration of an electrolyte in a solution or body compartment is measured in mEq/L

• Electrolytes can move from one compartment to another

Intra vs. Extra

• Potassium • Calcium• Phosphate• Magnesium

• Sodium• Chloride• Calcium• Bicarbonate

Nonelectrolytes

• Other substances that dissolve in H2O• Urea, protein, glucose, creatinine, bilirubin• Measured in mg/dl

Osmolality

• Concentration of a solution• Determined by the # of particles/Kg of H2O• changing osmolality of one compartment

affects the osmolality of another compartment

Osmolarity

• The concentration of particles in a body of water

• Measured per liters of fluid

Fluid Regulation

• Kidneys– control extracellular fluid by adjusting

concentration of electrolytes, the osmolality of body fluids, volume of extracellular fluid, blood volume, and pH

– nephron is fixing unit of kidney, made of glomerulus (filtering) and tubules (reabsorption)

Kidney

• Controlled by hormones and processes

• Filtration - blood enters via renal artery. 20% because filtrate and enters the glomerular capsule, goes thru the tubules and is transformed into urine by reaborption. Other 80% leaves thru renal vein.

Kidney

• Reabsorption - occurs in the tubules. Important of adjusting volume and decomposition of filtrate preventing excessive fluid loss.

• Secretions - last phase, filtrate transformed to urine. Substances pass from blood into tubules and eliminated to maintain fluid and electrolyte balance.

Hormones

• Aldosterone - released by adrenal glands, increases reaborption of Na+ and decreases reaborption of K+

• Antidiuretic Hormones - produced by hypothalamus and secreted by the posterior pituitary. Causes the kidney tubules to reabsorb more H2O, so urine is more concentrated and there is less fluid loss

Thirst

• Regulates fluid intake• Increased osmolality stimulate osmoreceptors

in the hypothalamus to start the sensation of thirst

• Kidneys are alerted to conserve H2O

Fluid Gains/Losses

• Healthy individuals have = I/O• Urine output is 1-2L/day• Seating causes H2O and electrolyte losses• H2O loss in lung via evaporation approximately

300-400 ml/day• GI tract loses 100-200ml/day via reabsorption

in the small intestine

Age-Related Changes

• Kidney functioning slower• Reduced sense of thirst• Total body H2O declines• Chronic conditions which contribute to

imbalances• Decreased need for fluid

Basic Principles of IV Fluid Replacement

• Iso-osmolar - has the same amount of particles (sodium, glucose, urea, or protein) and water

• Hypo-osmolar - has fewer particles than water• Hyper-osmolar - has more particles than water• 4 major categories of IV fluid replacement

– crystalloids– colloids– lipids– blood products

Crystalloids and Colloids

• Crystalloids - dextrose, saline, and lactated Ringer’s solutions

• Used for replacement and maintenance of body fluids

• Colloids - amino acids, plasmanate, and dextran solutions

• Used as volume expanders

Crystalloids

• Isotonic Solutions– sodium chloride 0.9% – lactated Ringer

• Hypotonic Solutions (hydrating)– dextrose 2.5%, 5%, 10%– dextrose 2.5% in 0.45 NaCl– dextrose 5% in 0.45 NaCl

Crystalloids (cont.)

• Maintenance Solutions– Plasmalyte 56– Plasmalyte 148– Isolyte

• Hypertonic Solutions– sodium chloride 3%– sodium chloride 5%

Colloids

• Protein Solutions– Aminosol 5%– Aminosol 5% with dextrose 5%

• Plasma Expanders– Dextran 40 10% in normal saline or 5%

dextrose in water– Dextran 70 6% in normal saline or 5%

dextrose in water

Assessment

• Health History– kidney disease, diabetes, vomiting, diarrhea,

salicylate poisoning, CHF, burns, cerebral injuries, ulcerative colitis, hormone imbalances

– risk factors: diuretics, cathartics, gastric suctioning

– complaints: fatigue, palpitations, dizziness, edema,dyspnea, confusion

Assessment

• Vital Signs– fever causes fluid and electrolyte loss– pulse will increase in response to volume loss– electrolyte changes can affect conduction of

impulses in the heart– respiration is minimally affected– blood pressure directly related to blood volume

Assessment

• Intake and output• Body weight: same scale, same time, same

clothes. 1L=2.2lbs• Skin: color, moisture, temperature, facial

characteristics, edema• Mucous membranes• Veins: neck vein distension

Diagnostic Tests

• Urine– pH (4.6 - 8.0)– specific gravity (1.010 - 1.025)– osmolality– creatinine clearance– sodium– protein

Diagnostic Tests

• Blood– hematocrit %– blood urea nitrogen(BUN)– osmolality– electrolytes

Electrolyte Imbalances

• Major Electrolyte Categories– SodiumSodium and PotassiumPotassium– Calcium Calcium and MagnesiumMagnesium

• Electrolyte Conditions– Hyponatremia and hypernatremia– Hypokalcemia and hyperkalcemia– Hypocalcemia and hypercalcemia– Hypomagnesemia and hypermagnesemia

Hyponatremia• Serum levels drop below 135 mEq/L• C/M

– headache, muscle weakness,fatigue, abdominal cramping, postural hypotension,confusion

• Treatment– Fluid restriction– Sodium chloride 0.9% (Isotonic)– Ringer’s solution (Isotonic)– Sodium chloride 3% - if severe

Hypernatremia• Serum level is above 150 mEq/L• C/M

– thirst, flushed skin, dry mucous membranes, restlessness, increased HR, low urine output, postural hypotension, convulsions

• Treatment– Reduced salt intake– Increase PO and IV replacement– Dextrose 5% in water (Hypotonic)

Hypokalemia• Serum level is below 3.5 mEq/L• C/M

– anorexia, nausea and vomiting, neurological disturbances, muscle cramps, polyuria, dyspnea, shallow respirations,confusion,dysrhythmias

• Treatment– Oral potassium replacements: Potassium chloride,

Slow-K, K-Dur, Micro-K, K-Tab – Parenteral potassium replacements

• Nursing alertNursing alert– Over correction resulting in hyperkalemia

Hyperkalemia• Blood level is above 5.8 mEq/L• C/M

– explosive diarrhea, muscle cramps, weakness, paresthesias, irritability, anxiety, decreased urine output, abdominal cramps, dysrhythmias

• Treatment – Sodium polystyrene sulfonate (Kayexalate)– Potassium-sparing diuretics – Dextrose solutions with insulin– IV Calcium gluconate 10%

Hypocalcemia• Serum level is below 4.5 mEq/L

• C/M– numbness and tingling around mouth, hyperreflexia,

tetany, seizures

• Treatment

– Oral and IV calcium salt supplements : carbonate, chloride, lactate, citrate, gluconate

– Vitamin D supplements

– IV lipids

Hypercalcemia• Blood level is above 5.5 mEq/L• C/M

– lethargy, confusion, N/V, depressed reflexes,bone pain, polyuria, stupor, coma

• Treatment– Sodium chloride 0.9% (Isotonic)– Biophosphonates: pamidronate (Aredia)– Corticosteroids: Predisone– Antibiotic: mithramycin – IV magnesium sulfate

Hypomagnesemia• Blood level is below 1.5 mEq/L• C/M

– confusion, hyperreflexia, tremors, seizures

• Treatment– Oral and enema magnesium salt

supplements: hydroxide (MOM), sulfate (Epsom), citrate

– IV magnesium sulfate

Hypermagnesemia• Blood level is above 2.5 mEq/L• C/M

– lethargy, N/V, depressed reflexes, cardiac arrest

• Treatment– Diuretics: Mannitol– Corticosteroids: Predisone– IV Calcium gluconate

Complications of IV and Electrolyte Replacement

• Infiltration• Thrombosis• Thrombophlebitis• Pain at insertion site• Necrosis• Pulmonary edema• Pyrogenic reactions• Air emboli