week 2 - fluid and electrolyte regulation

2/3

what portion of total body fluid is intracellular fluid?

1/3

what portion of total body fluid is extracellular fluid?

1/3

what portion of extracellular fluid is plasma?

2/3

what portion of extracellular fluid is interstitial fluid?

minimal amounts

what portion of extracellular fluid is transcellular fluid?

intravascular fluid (plasma)

1/3 of ECF, fluid within blood vessels that is the primary transport system within the blood

interstitial fluid

2/3 of ECF, the fluid surrounding body cells, supplying them with essential nutrients and oxygen while clearing away waste products

transcellular fluid

there are minimal amounts of this fluid within the body, this includes specialized fluids that are contained within specific body compartments such as CSF, intraocular fluid, digestive secretions, and synovial fluid

increased vascular volume

interstitial fluid to plasma shift leads to…

edema

plasma to interstitial fluid shift leads to…

K+

main cation in intracellular fluid

PO43-

main anion in intracellular fluid

Na+

main cation in extracellular fluid

Cl-

main anion in extracellular fluid

simple diffusion

particles move from areas of high concentration to areas of low concentration. this process does not require energy

facilitated diffusion

carrier proteins move molecules down a concentration gradient. this process does not require energy

active transport

particles move against the concentration gradient (low to high) using ATP. this process requires energy

osmosis

the movement of water across a semipermeable membrane

osmolality

the number of dissolved particles per kilogram

osmotic pressure

amount of pressure required to stop osmotic flow of water, this is determined by the concentration of solutes in solution.

fluid tonicity

describes how the osmolality of two solutions compare to each other.

isotonic

solutions concentration is the same as normal body fluid

hypotonic

solutions concentration is less than normal body fluid

hypertonic

solutions concentration is high than normal body fluid

0.45% NaCl

hypotonic IV solution example, used as a “free water replacement,” monitor for mental status changes that may indicate cerebral edema

0.9% NaCl, lactated ringers

isotonic IV solution example, ideal for resolving an intravascular fluid volume deficit

3% saline

hypertonic IV solution example, expands circulating blood volume for severe symptomatic hyponatremia. requires frequent monitoring of BO, lungs, and sodium levels

colloid solutions

fluids that contain large, heavy molecules which do not easily pass through blood vessel walls, keeping fluid inside the bloodstream. example: albumin. also called plasma/volume expanders because the large molecules will pull and keep fluid in the vascular space.

ADH

acts on the distal renal tubules, promoting the reabsorption of water

renal tubules

the site of action of ADH, aldosterone, and other hormones

aldosterone

causes increased sodium and water retention in the kidneys

cortisol

mainly glucose elevating and has anti-inflammatory effects

natriuretic peptides

produced by cardiomyocytes in response to increase atrial pressure. this supresses the secretion of aldosterone, renin, and ADH to lower overall blood volume and pressure

aging adult considerations

decreased renin and aldosterone

increased ADH and ANP

kidneys are less able to conserve water

loss of lean body mass leads to less total body water

fluid volume deficit manifestations

hypotension, tachycardia, dizziness, weight loss, slow capillary refill, decreased skin turgor

fluid volume deficit treatment

replace water and electrolytes with oral intake and/or IV fluids

monitor cardiovascular status

consider daily weight

monitor intake and output

prevent falls

protect skin

monitor for fluid volume overload if giving IV administration

fluid volume deficit causes

abnormal losses, inadequate intake, or plasma-to-interstitial shift

fluid volume excess causes

excessive intake, abnormal retention, or interstitial-to-plasma shi

fluid volume excess manifestations

JVD, bounding pulse, hypertension, weight gain, edema, headache, lung crackles

fluid volume excess treatment

fluid restriction, diuretics, monitor intake and output

functions of sodium

ECF volume and concentration, generation and transmission of nerve impulses, muscle contractility, acid-base balance

hypernatremia causes

lack of water intake, excess sodium intake (receiving hypertonic solutions, ingestive sea water), lack of ADH, excessive water loss

manifestations of hypernatremia

SALT: skin flushed, agitation, lethargy, thirst, seizures, coma

management of hypernatremia

if fluid deficit: replace fluid orally or IV (isotonic fluids)

if fluid balanced or excess: sodium-free IV fluids and diuretics

hyponatremia causes

loss of sodium-rich fluids (wounds, diarrhea, vomiting)

water excess (too much ADH, hypotonic IV fluids)

hyponatremia manifestations

CASH: confusion, abdominal cramps, seizures, headache

hyponatremia management

if water excess: fluid restriction

if from abnormal fluid loss: IV fluids with sodium

3% saline solution if very low sodium

functions of potassium

transmission and conduction of nerve and muscle impulses

cellular growth

maintenance of cardiac rhythms

acid-base balance

hyperkalemia causes

impaired renal excretion

shift from ICF to ECF (burns, crushing injury, tumor lysis, severe infection)

intake (meds, salt substitutes)

hyperkalemia manifestations

IMAD: irritability, muscle weakness, abdominal cramping, dysrhythmias

hyperkalemia treatment

stop potassium intake and increase elimination (diuretics, dialysis, kayexalate)

IV insulin or sodium bicarbonate to force potassium into cells

reverse membrane effects with calcium gluconate IV

hypokalemia causes

increased loss (NG suction, diuretics, diarrhea, dialysis)

shift from ECF to ICF (increased insulin, alkalosis)

dietary deficiency (rare)

hypokalemia manifestations

WALT: weakness, arrhythmias, leg cramps, thready irregular pulse, decreased GI motility

hypokalemia treatment

increase dietary intake

oral or IV KCl supplements

***must ensure adequate renal finction of giving KCl through an IV

calcium functions

formation of teeth and bones

blood clotting

transmits nerve impulses

heart and muscle function

hypercalcemia causes

hyperparathyroidism

malignant tumors (cancer destroys bone tissue)

prolonged immobilization

hypercalcemia manifestations

OLDMAPS:

osteoporosis

lethargy

depressed reflexes

memory problems

abdominal symptoms

pain (bones)

stones (kidney)

hypercalcemia treatment

decrease intake and promote excretion (loop diuretic)

hydration and isotonic saline infusion

mobilization

meds: synthetic calcitonin and biphosphonates

hypocalcemia causes

decreased production of parathyroid hormone (often after thyroid surgery)

acute pancreatitis

kidney disease

alcoholism

multiple blood transfusions

alkalosis, low albumin, elevated phosphorus

hypocalcemia manifestations

CATS: cardiac dysrhythmias, abnormal (positive) trousseaus or chvosteks sign, tingling/tetany, spasms/stridor

hypocalcemia treatment

oral or IV calcium supplements

treat pain and anxiety to prevent hyperventilation induced respiratory alkalosis

magnesium functions

coenzyme in protein and carbohydrate metabolism

required for nucleic acid and protein synthesis

necessary for sodium-potassium pump

important for normal neuromuscular and cardiac function

hypermagnesemia causes

high intake with renal issues

excess IV administration

hypermagnesemia manifestations

DINR: drowsiness, impaired reflexes, nausea/vomiting, respiratory/cardiac arrest

hypermagnesemia treatment

decrease intake

enhance removal using IV furosemide or dialysis

IV CaCl or calcium gluconate

****do not take magnesium containing drugs with kidney issues

hypomagnesemia causes

low intake (prolonged fasting/starvation)

loss from GI tract or diuretics

alcoholism

uncontrolled diabetes

hypomagnesemia manifestations

BST MD: brisk deep tendon reflexes, seizures, tremors, muscle cramps, dysrhythmias

hypomagnesemia treatment

increase intake through foods or IV