Fluid and electrolytes

aldosterone

acts on the distal convoluted tubule of the kidney to increase the amount of water and sodium reabsorbed back into the bloodstream, is released when the adrenal cortex is stimulated.

antidiuretic hormone (ADH)

A hormone secreted by the pituitary gland that maintains serum osmolality by controlling the amount of water excreted in the urine.

colloids

Substances such as proteins that do not dissolve easily.

crystalloids

substances that dissolve easily in water

dehydration

Hypertonic volume deficit occurs when water is lost in excess of sodium. As fluid loss continues, the circulating fluid volume decreases, and serum osmolarity increases. Even the small losses of fluids can lead to undesirable consequences. Severity of deh

diffusion

the movement of solutes across a selectively permeable membrane from areas of higher concentration to areas of lower concentration until equilibrium is reached. Diffusion is influenced by temperature, molecular weight, steepness of the concentration gradi

edema

the abnormal accumulation of fluid in the interstitial spaces, typically in the face, fingers, abdomen, ankles, and feet. Assessing fluid volume excess (FVE) is by looking at increased total body weight: a 2% gain is mild excess, 5% gain is moderate exces

electrolytes

Charged atoms or molecules(ions) that conduct electrical impulses across cells. They carry a positive charge(cations) or a negative charge(anion).

extracellular fluid

Fluid outside of the cell; interstitial, intravascular, or transcellular, this includes cerebrospinal, synovial, peritoneal, pleural, and pericardial fluids.

fluid volume deficit (FVD)

Occurs with excessive loss or inadequate intake of fluid. Two types of fluid deficits can occur: Isotonic and Hypertonic. Isotonic (Hypovolemia) occurs when water and sodium are lost at the same rate. Hypertonic occurs when water is lost in excess of sodi

fluid volume excess (FVE)

Fluid volume excess occurs when intake exceeds output. Fluid volume excess is isotonic or hypotonic, depending on corresponding changes in serum osmolarity.

Homeostasis

is the maintenance of fluid balance, is controlled by several physiological mechanisms, including the renin-angiotensin system, the secretion of the antidiuretic hormone, and the thirst mechanism. Homeostasis is monitored by the kidneys through changes in

hydrostatic pressure

Hydrostatic pressure is the force of the fluid pressing against the blood vessel; it is controlled by the force of myocardial contraction, rate of contraction and blood flow. The force, or pressure, is different on the arterial and venous sides of the cap

hyperkalemia

occurs when the serum potassium level is greater than 5.0 mEq/L. This imbalance results from excessive intake of potassium, transfusions and medications, impaired renal excretion, and cellular movement.

hypokalemia

occurs when the serum potassium level falls below 3.5 mEq/L. Inadequate intake occurs as a result of decreased oral intake or insufficient potassium in intravenous (IV) fluids.

Hypernatremia

occurs when the serum sodium level is greater than 145 mEq/L. This imbalance results from a greater loss of water compared with sodium or a greater intake of sodium.

hyponatremia

occurs when the sodium level is decreased in relation to body water. It is defined as a serum level less than 135 mEq/L.

hypertonic solution

pulls water from the cell to the extracellular fluid compartment, causing cellular shrinkage.

hypotonic solution

Excess water moves into the cells, producing cellular swelling.

hypovolemia

A decrease in fluid volume, specifically a condition marked by the loss of fluid and solutes from extracellular fluid that, if left untreated, can progress to hypovolemic shock.

isotonic solution

An administered solution that has the same osmolarity as blood plasma. the osmolality concentration is between 240 and 340 mOsm/kg (A milliosmole (mOsm) is 1/1,000 of an osmole)

milliequivalent

denotes the ability of cations to bond with anions to form molecules. Electrolytes are measured in milliequivalents per liter of water (mEq/L).

oncotic pressure

in the intravascular space is controlled by the concentration of plasma proteins, specifically albumin. This is known as colloid osmotic pressure, or oncotic pressure

orthostatic hypotension

When a patient moves from a lying or sitting position to a standing position, orthostatic hypotension can occur. There is a sudden drop in systolic pressure (20 mmHg drop) and a drop in diastolic pressure (10 mmHg drop). The low pressure occurs from perip

osmolality

refers to the number of osmoles (unit of pressure) per kilogram of solvent. This term is used interchangeably with osmolarity

osmolarity

the number of osmoles per liter of solvent. This term is used interchangeably with osmolality. For this chapter you will use osmolarity most often.

osmoreceptors

They monitor the osmolarity of the blood plasma and are located in the hypothalamus

osmosis

the movement of water across cell membranes; osmotic pressure

renin-angiotensin system

regulates blood pressure and fluid balance through vasoconstriction and excretion or reabsorption of sodium.

tonicity

the level of osmotic pressure of a solution; isotonic, hypertonic, hypotonic

three functions of water in the body

transports nutrients, regulates body temperature, lubricates joints

How does the body regulate fluid volume to maintain homestasis?

several body systems, and hormones help regulate. Water is brought into the body through intake of fluids or foods. Excreted as urine.

What is the average daily intake/output of fluids? (mL)

2500 mL

Why are infants TBW higher than older adults?

Infants have more extracellular fluid than intracellular fluid because they have a large body and lung surface area compared to their body mass, and they have immature kidneys that have little reserve capacity.

Why are older adults TBW lower than infants?

thirst sensation is blunted causing the osmolarity to rise before they realize they're thirsty, resulting in decreased fluid intake. Also, older adults have decreased lean body mass, which decreases their TBW percentage

What are risk factors for infants regarding fluid and electrolyte balance?

they are at risk because they have high levels of total body water

What are risk factors for elderly regarding fluid and electrolyte balance

They are more prone to hypokalemia because of diuretic use

What diagnostic tests should the RN monitor with alterations in fluid and electrolyte balance?

Levels of serum electrolytes, BUN, Serum osmolarity, RBCs, HGB, Hematocrit, Serum albumin, Urinalysis

What is fluid volume deficit (FVD)?

occurs with excess loss of inadequate intake of fluid.

isotonic FVD causes:

Hemorrhage, burns, vomiting, diarrhea, Addison disease, fever, excessive perspiration.

clinical manifestations of isotonic FVD are...

Confusion, thirst, dry mucous membranes, orthostatic hypotension, tachycardia, weak and thready pulse, decreased skin turgor, prolonged capillary refill, and decreased urinary output.

Lab findings of isotonic FVD...

Urine specific gravity >1.030, Increased hematocrit: Adult males >52; Adult females >48, BUN >20.

Nursing interventions for isotonic FVD

Administer fluids, monitor vital signs, monitor intake and output, monitor laboratory results, especially hematocrit, BUN, and urine specific gravity.

hypertonic FVD causes:

Diabetes insipidus, diabetic ketoacidosis,administration of osmotic diuretics, hypertonic enteral tube feedings, or hypertonic intravenous fluids; prolonged vomiting and diarrhea.

clinical manifestations of hypertonic FVD...

Similar to hypovolemia, dry sticky mucous membranes, flushed dry skin, increased body temperature, irritability, convulsions, and coma.

lab findings for hypertonic FVD

Urine specific gravity >1.030, Increased hematocrit: Adult males >52, Adult females >48, BUN >20, Serum sodium >145.

nursing interventions for hypertonic FVD

Administer fluids, monitor vital signs, monitor intake and output, assess for neurologic changes, monitor laboratory results, especially hematocrit, BUN, and urine specific gravity.

What is fluid volume excess (FVE)?

occurs when fluid intake exceeds output

isotonic FVE causes:

Congestive heart failure, renal failure, and cirrhosis.

clinical manifestations of isotonic FVE are

Weight gain, edema in dependent areas, bounding peripheral pulses, hypertension, JVD, dyspnea, cough, abnormal lung sounds.

lab findings for isotonic FVE

Urine specific gravity <1.005, decreased hematocrit: Adult males <42, Adult females <37, BUN <7.

Nursing interventions for isotonic FVE

Monitor vital signs, monitor intake and output, assess for edema and JVD, auscultate lung fields, monitor laboratory results, especially hematocrit, BUN, and urine specific gravity

hypotonic FVE causes

Excessive water intake, prolonged use of hypotonic IV solutions, SIADH (Syndrome of inappropriate antidiuretic hormone secretion)

clinical manifestations of hypotonic FVE

Symptoms similar to isotonic fluid volume excess plus neurologic changes that indicate cerebral edema, including decreased level of consciousness, coma, and convulsions

lab findings for hypotonic FVE

Urine specific gravity <1.005, decreased hematocrit: adult males <42, adult females <3, BUN <7, serum sodium <135

nursing interventions for hypotonic FVE

Monitor vital signs, monitor intake and output, assess for neurologic changes, monitor laboratory results, especially hematocrit, BUN, and urine specific gravity

What assessment changes would you expect with isotonic FVD?

Confusion, thirst, dry mucous membranes, orthostatic hypotension, tachycardia, weak and thready pulse, decreased skin turgor, prolonged capillary refill, and decreased urinary output

What assessment changes would you expect with hypertonic FVD?

Similar to hypovolemia, dry sticky mucous membranes, flushed dry skin, increased body temperature, irritability, convulsions, and coma

What assessment changes would you expect with isotonic FVE?

Weight gain, edema in dependent areas, bounding peripheral pulses, hypertension, JVD, dyspnea, cough, abnormal lung sounds

What assessment changes would you expect with hypotonic FVE?

Symptoms similar to isotonic fluid volume excess plus neurologic changes that indicate cerebral edema, including decreased level of consciousness, coma, and convulsions

normal range for sodium

135-145 mEq/L

What are food sources of sodium in the body?

Meats: especially red meats, fish, eggs and dairy: cheese and milk, yeast breads, soups, pastas and some fruits and veggies

What are four functions of sodium in the body?

is the principal ion responsible for resting membrane potential of cells, it is essential in depolarization and needed for nerve and muscle function, it's the principal cation of the extracellular fluid (it accounts for 90-95% of the osmolarity), and it p

What focused assessment should the nurse perform with an alteration in sodium?

neuromuscular, cognitive, and urinary intake/output assessements

normal range for potassium

3.5-5.3 mEq/L

What are food sources of potassium?

Milk, bananas, legumes, green leafy vegetables, orange juice, tomatoes, vegetable juice, avocados, and cantaloupe

What are three functions of potassium in the body?

Produces resting membrane potentials of nerve and muscle cells.
Principal cation of the intracellular fluid and responsible for intracellular osmolarity.
Essential component of the sodium-potassium pump and involved in protein synthesis.

What focused assessment should the nurse perform with an alteration in potassium?

cardiovascular, renal, and neuromuscular assessments

What are four nursing diagnosis for individuals with alterations in fluid and electrolytes?

Excess fluid volume, Decreased fluid volume, Impaired renal volume, and Decreased cardiac output.

What are some patient-centered interventions for individuals with alterations in Fluid & Electrolytes?

Some patient-centered interventions for individuals with alterations in fluid and electrolytes are restricting fluid intake, restricting electrolyte intake, fluid replacement, electrolyte replacement, and intravenous (IV) therapy.

What are outcomes/goals for individuals with alterations in Fluids & Electrolytes?

The patient will exhibit no edema within 48 hours, patient's intake and output will be balanced by the end of the next shift, urine specific gravity will be within the normal limits on the next urinalysis, patient's mucus membranes will be moist by the en

what are cyrstalloids

solutes that dissolve easily

what are colloids

solutes that do not dissolve easily

what fluid shift will occur in a isotonic solution

the solution has the same osmolarity as blood plasma. Isotonic solutions cause an equal amount of water to move into and out of the cell.

What fluid shift will occur in a hypotonic solution

the solution has a lower osmolarity than body fluids. Administering a hypotonic solution causes excess water to move into the cells, producing cellular swelling.

What fluid shift will occur in a hypertonic solution

the solution has a higher osmolarity than body fluids. Administering a hypertonic solution will cause water to move out of the cells causing cellular shrinkage