Fluid & Electrolytes Study Set

Study set for 101 - Fluid & Electrolytes

active transport

a kind of cellular transport where substances move against a concentration gradient using energy (low to high)

diffusion

ions & molecules move from an area of high to low concentration

the outcome is even distribution of the solute within the solution

electrolytes cannot diffuse across cell membranes unless the membranes have proteins that serve as ion channels

opening and closing of ion channels play an important role in nerve & muscle function

osmosis

equalizes the concentration of molecules on each side of the membrane

filtration

net effect of several forces

movement of solutes & solvents by hydrostatic pressure

movement from high to low area of pressure

fluid moves into and out of capillaries (between vascular & interstitial spaces)

osmolality

measure of the number of particles dissolved in solutions

serum osmolality

determined by the fluid volume & the amount of particles, (275-295 mOsm/kg)

sodium, bicarb, proteins, glucose & urea in the extracellular compartments

affects tonicity

isotonic

0.9% NS
LR
D5W

hypotonic

0.45% NS
0.22% Saline
0.33% Saline
D5W

hypertonic

D10W
3% or 5% NaCl
D5 0.45% NS
D5 0.9% NS
D5 LR

fluid volume

body balances _____ through:

-thirst
-kidneys
-renin-angiotensin-aldosterone system
-antidiuretic hormone (ADH)
-atrial natriuretic peptide

thirst center

decrease in extracellular volume, ____ is stimulated

renin

a decrease in renal perfusion (in response to a decrease in extracellular volume) leads to the kidneys releasing _____; which produces angiotensin I which converts to angiotensin II

renin

____ causes vasoconstriction of blood vessels to relocate & increase blood flow to kidneys and improves renal profusion

vasoconstriction helps to regulate blood pressure

stimulates the release of aldosterone

aldosterone

regulates ECV: influences how much Na+ and H2O are excreted in the urine

released by the adrenal cortex in response to increased K+ concentration or as the end-product of the RAAS

acts on the distal portion of the renal tubule to increase reabsorption of Na & excretion of K+

acts as a volume regulator

antidiuretic hormone

stored in the posterior pituitary gland; regulates the osmolality of fluid; released in response to changes in blood osmolality

circulates to kidneys and acts on collecting ducts, causing to resorb water

prevents:
- diuresis

blood becomes diluted; osmoreceptors stop the release of ADH to restore urine output

atrial natriuretic peptide (ANP)

hormone secreted from cells of atrium when heart is stretched by fluid overload

blocks secretion of aldosterone

inhibits renin secretion

acts as a diuretic

reduces fluid volume by increasing Na and H2O excretion

can be released due to orthostatic changes, atrial tachycardia, high sodium, sodium chloride infusions, and drugs that cause vasoconstriction

fluid balance

helps maintain body temp and cell shape

helps transport nutrients, gases, & wastes

most of the body's major organs work together to achieve this

different types of fluids are located in different compartments

maintain homeostasis by moving through body by going back & forth across cell's semipermeable membrane

distribution of fluids varies with age

fluid intake

major factor: thirst mechanism

osmolality increases

hypothalamus

region of the brain that stimulates thirst; osmolality increases, then ____ stimulates thirst

insensible water loss

continuous & occurs through the skin & lungs

sensible water loss

occurs through visible perspiration, directly related to stimulation of sweat glands

hypovolemia

causes:
* fluid loss
* reduced fluid intake
* fluid shift out of the vascular space

conditions that result in _____:
* fluid loss
* hemorrhage
* frequent urination
* vomiting / diarrhea
* fistulas
* fever
* excessive NG suctioning

reduced fluid intake
* dysphagia
* unconscious states
* lack of fluids
* lack of supplemental water when receiving concentrated tube feedings
* reduced ability to sense taste (elderly)

fluid shift out of vascular space
* burns
* acute intestinal obstruction
* pancreatitis
* crushing injuries

treatment:
* monitor respiratory rate, effort, and POX
* check urinalysis, CBC, electrolytes
* administer O2 PRN
* check for orthostatic hypotension
* neuro checks for LOC
* assess heart rhythm
* initiate & maintain IV access
* oral & IV hydration
* monitor I&O - alert if urine output < 30 mL/hr

hypervolemia

CAUSES

INADEQUATE WATER AND SODIUM ELIMINATION
* elevated corticosteroid levels as in hyperaldosteronism or Cushing's disease
* heart failure
* liver failure and cirrhosis
* renal failure

EXCESS SODIUM INTAKE IN RELATION TO OUTPUT
* excessive administration of parenteral fluids containing sodium
* excessive dietary intake
* excessive ingestion of sodium-containing medication, home remedies or OTC medications

EXCESSIVE FLUID INTAKE IN RELATION TO OUTPUT
* administration of blood or parenteral fluids at excessive rates
* ingestion of fluid in excess of elimination

____________________________________________

MANIFESTATIONS
* acute weight gain
** mild fluid volume excess = 2%
** moderate fluid volume excess = 5%
** severe fluid volume excess = 8% or more

increased interstitial fluid volume
* dependent and generalized edema

increased vascular volume
* full and bounding pulse
* pulmonary edema
*** cough
*** crackles
*** dyspnea
*** shortness of breath
* venous distention

electrolytes

cations and anions, functions are osmosis, electrical current & maintaining acid-base balance

cations

electrolytes with a positive charge

anions

electrolytes with a negative

sodium

135-145 mEq/L
cation

potassium

3.5-5.0 mEq/L
cation

ionized calcium

4-5 mEq/L
cation

total calcium

8.5-10.5 mg/dl
cation

magnesium

1.5-2.5 mEq/L
cation

chloride

95-108 mEq/L
anion

arterial bicarbonate

22-26 mEq/L

venous bicarbonate

24-30 mEq/L

phosphate

2.5-4.5

hypernatremia

> 145 mEq/L sodium
think: big and bloated

* sudden weight gain overnight
* skin: flushed and rosy red
* polydipsia: excessive thirst

cardiac: neck vein distention, crackles in the lungs

late & serious s/s: swollen dry tongue, confusion, pulmonary edema

neurological deficits: restlessness, fatigue, abdominal cramping

excessive sodium intake

ingestion of large amounts of concentrated salt solutions

hyponatremia

sodium

role is to maintain BP, blood volume, and pH
activates nerve & muscle cells balance

hypernatremia

monitor LOC
provide oral hygiene
monitor intake & output
maintain a low sodium diet
encourage oral fluids as prescribed
administer diuretics PRN

hyponatremia

* intake and output
* daily weights
* VS, LOC, report irregular findings
* encourage slow position changes
* follow prescribed fluid restrictions
* monitor resp. status if muscle weakness is noted
* encourage foods & fluids high in sodium (cheese, milk, condiments)
* IV soln - hypertonic 3% NaCl

potassim

3.5 - 5.0 mEq/L
Role is to maintain heart, skeletal & smooth muscle contraction

hyperkalemia

potassium >5.0 mEq/L

cardiac:
* tight and contracted
* ST elevation & peaked Q waves
* hypotension & bradycardia
* severe: V Fib & cardiac standstill

GI:
* tight & contracted
* diarrhea
* hyperactive bowel sounds

Neuromuscular:
* tight & contracted
* parathesias
* increased DTRs
* profound muscle weakness

respiratory: resp failure if SEVERE

neuro: confusion

CAUSES OF _____:
* medications : ACE inhibitors, NSAIDS
* acidosis : metabolic & respiratory
* cellular destruction
* hyperaldosteronism, hemolysis
* intake : excessive
* nephrons, renal failure
* excretion : impaired

SIGNS AND SYMPTOMS
* muscle weakness
* urine output decreased
* respiratory distress
* decreased cardiac contractibility, low BP/P
* early signs of muscle twitching & cramps - profound weakness
* rhythm changes, can advance to cardiac arrest

NURSING MANAGEMENT:
* assess dietary K+ intake
* monitor renal function
* patient teaching includes use of ACE inhibitors, limit amt. of foods containing K+
* client will need continuous ECG monitoring while in the hospital to monitor for arrhythmias
* monitor BS levels with insulin administrations
* monitor cardiac, resp, neuromuscular & GI status & prepare for dialysis

MEDICAL MANAGEMENT:
* eliminate potassium
* promote excretion of potassium
* KAYEXALATE
* LASIX (furosemide)
* insulin IV to push potassium from
* IV Calcium gluconate may be given immediately to patients experiencing cardiac arrhythmias secondary to life-threatening potassium levels

hypokalemia

potassium < 3.5 mEq/L

cardiac: low and slow
* flat or inverted T waves
* ST depression
* prominent U wave

GI: low and slow
* constipation, hypoactive bowel sounds
* abdominal distention, paralytic ileus

Neuromuscular: low and slow
* decreased DTRs, muscle weakness

Respiratory: resp. failure, if severe

Neuro: confusion


Causes:
* alcoholism
* alkalosis
* anorexia nervosa
* cushing syndrome
* diuretics
* hyperalimentation
* prolonged vomiting & diarrhea
* inadequate intake

causes:
* administration of potassium-free parenteral solutions
* inability to eat
* diarrhea
* vomiting

Manifestations
* impaired ability to concentrate urine
* polydipsia
* polyuria
* urine with low specific gravity and low osmolality

GI manifestations:
* abdominal distention
* paralytic ileus
* anorexia, nausea, vomiting

Neuro:
* muscle flabbiness, fatigue, weakness
* cramps and tenderness

Cardiac:
* arrhythmias
* changes in ECG
* postural hypotension


confusion, depression

metabolic alkalosis

FOODS:
* ORANGES
* BANANAS
* CANTALOUPES
* PRUNES
* SQUASH
* RAISINS
* DRIED BEANS
* POTATOES
* SWEET POTATOES

hypochloremia

chloride is nor normally lost in the urine, sweat, and stomach secretions. excessive lost can occur from heavy sweating, vomiting, and adrenal gland and kidney disease

when serum chloride levels fall, metabolic alkalosis occurs

s/s:
* metabolic alkalosis
* hypertonicity of muscles
* depressed respiration
* if severe, tetany

treatment:
* ID cause & replacement therapy

hyperchloremia

can occur as a result of hyponatremia or increased bicarbonate levels

elevations in chloride may be seen in diarrhea, certain kidney diseases, and sometimes in over activity of the parathyroid glands

hyperchloremia is rare but may occur with a bicarbonate deficiency and dehydration. same s/s as hypernatremia, everything is BIG AND BLOATED!

s/s:
* metabolic ACIDosis
* stupor
* deep, rapid respirations
* weakness
* if severe, coma

treatment:
* treat metabolic acidosis
* sodium bicarb IV
* IV soln, LR

chloride

normal levels are 95-108 mEq/L
role is to maintain BP, blood volume, and pH

neuromuscular function
transmission of nerve impulses
contraction of skeletal & cardiac muscle
clotting of blood
maintenance of normal cell membrane permeability
formations of bones & teeth

hypocalcemia

Trousseau's sign and Chvostek's sign can be seen in _______.

calcium

8.5-10.5 mg/dL

hypercalcemia

> 10.5 mg/dL calcium
* increased Ca intake & absorption
* milk alkali syndrome

Shift Ca out of the bone
* prolonged immobilization
* hyperparathyroidism
* osteometastasis
* paget's disease

Decreased Ca output
* thiazide diuretics

NURSING MANAGEMENT
* increase oral intake of fluids to 3-4 L/day
* safety precautions for client at risk for injury
* be aware of altered gait and weakness
* assess neuro status every 4 hours-LOC, orientation
* encourage increased mobility
* monitor IV site for infiltration, erythema, pain
* monitor arrhythmias
* teach client to limit foods high in calcium, and avoid vitamin D supplements

hypocalcemia

< 8.5 mg/dL calcium

Causes:
* decreased Ca intake & absorption
* chronic diarrhea
* calcium deficient diet
* vitamin D deficiency
* chronic renal failure
* laxative misuse
* steatorrhea

shift of Ca into bone or inactive form:
* hypoparathyroidism, rapid administration of blood, alkalosis, pancreatitis

increased Ca output
* chronic diarrhea, steatorrhea

NURSING MANAGEMENT:
* monitor Ca every 4-6 hours
* assess IV site for infiltration
* monitor cardiac rhythm & ECG changes
* assess for hypotension
* assess for chvostek's sign & trousseau's sign
* evaluate for paresthesia
* rapid IV administration can lead to rapid drop in BP, arrhythmias, and cardiac arrest

phosphorus

2.5-4.5 mg/dL
* main ICF anion
* essential to the function of muscle, red blood cells, and nervous system
* essential for bone formation
* promotes energy storage
* promotes carbohydrate, protein & fat metabolism
* acts as a hydrogen buffer

hypophosphatemia

lab values < 2.5 mg/dL phosphorus

Causes:
* decreased interstitial absorption
* antacids, lack of vitamin D
* severe diarrhea
* increased renal elimination
* alkalosis, DKA
* hyperparathyroidism
* renal tubular absorption
* malnutrition
* alcoholism
* TPN

MANIFESTATIONS
* neurologic:
** ataxia, confusion, stupor, coma, tremors, parathesias, seizures

MS
* bone pain, joint stiffness, muscle weakness, osteomalacia

Blood Disorders
* hemolytic anemia
* impaired WBC function
* platelet dysfunction with bleeding disorders

TREATMENT
* ID & treat underlying cause
* replacement therapy, either PO or IV, depending on severity

hyperphosphatemia

lab values: >4.5 phosphorus

causes:
active phosphate overload
* laxatives and enemas containing phosphate
* IV phosphate administration

intracellular to extracellular
* heat stroke
* massive trauma
* potassium deficiency
* seizures
* tumor lysis syndrome

impaired elimination
* hyperparathyroidism
* kidney failure

neuromuscular: parathesias, tetany

cardio: cardiac arrhythmias, hypotension

TREATMENT:
* ID & treat underlying cause
* restrict intake
* calcium based phosphate binders

magnesium

role: clotting cascade, modifies nerve impulse transmission & skeletal muscle, CHO & protein metabolism, synthesis of DNA

lab values magnesium : 1.5-2.5 mEq/L

hypermagnesmia

magnesium >2.5 mEq/L

cardiac: bradycardia, hypotension:: severe can cause dysrhythmias, cardiac arrest

GI: constipation, flushing, sensation of warmth, decreased LOC

MS: decreased DTRs, flushing, muscle weakness

Respiratory: decreased rate and depth


CAUSES
* increased intake & absorption
* excessive use of Mg containing laxatives & antacids
* parenteral overload of Mg

Decreased Mg output: oliguric end-stage renal disease, adrenal insufficiency

TREATMENT
* assess neuro status and reflexes - report absent DTR or decrease LOC
* monitor I&O
* check skin for flushing and diaphoresis
* monitor VS, bradycardia, low BP
* cont cardiac monitoring
* provide list of food and drugs to avoid

hypomagnesemia

bicarbonate

acts as a buffer to maintain the normal levels of acidity or pH in the blood and other fluids in the body

levels are measured to monitor the acidity of the blood and body fluids

the level of acidity if affected by medications that are taken or food that is ingested along with the function of the kidneys and lungs