Electrolyte Balance Flashcards
Hypovolemia
Too little fluid
Hypervolemia
Too much fluid
Third spacing
Fluid in the wrong place
Edema
Fluid shifting outside of primary space into interstial
(second spacing)
Water content acooutns for ___ of body weight
Around 600%
older adults water percentage
Less
Also thirst sensation decreases
Both contribute to risk for dehydration
Infant water percentage
70-80%
Why are we so careful when adminstiring fluid to infants
since they contain so much fluid, excess is very dangerous bc there’s not many places that the fluid can go if they get too much
Why do males have a lightly higher water content
Generally have more muscel wiuch holds more water
Intracellural fluid percentage
2/3 of fluid in the body
Inside the cells
Extracellular fluid perctange
1/3
Outside the cell
Plasma fluid
Interstitial space
Between the cells
Lympth/transcellualr fluid makes up abt _____ of our fluid
1 L
including CSF, synovial, peritoneal, pericardial
Transcellular
including lympth, CSF, synovial, peritoneal, pericardial
Electrolyte
Substances whose molecules dissociate into ions (charged particles) when placed into water
Cations
positively charged (Ca2+, Mg2+, K+, Na+)
Anions
negatively charged (HCO3-, Cl-, PO43-)
Prevelent cation inside the cells
Potassium
Prevelant anion inside cells
Phosphate
Prevelent cation in extracellular fluid
sodium
prevelant anion in extracellular fluid
Cholride (usually accompanies sodium)
Mechs controling fluid and lyte movment
Diffusion
Facilitated diffusion
Active transport
Osmosis
Hydrostatic pressure
Oncotic pressure
Diffusion
Movement of molecules from high to low concentration
Occurs in liquids, solids, and gases
Membrane separating two areas must be PERMEABLE to diffusing substance
Requires no energy
Facilitated diffusion
Movement of molecules from high to low concentration without energy
Uses specific protein CARRIER MOLECULES to accelerate diffusion across the cell membrane
Passive; requires no energy
Involving slightly more complex cells (Glucose transport ie.)
Osmosis
Movement of water bw two compartments by a membrane permaeable to water but not to solute
Moves from low solute to high solute conc
requires no energy
Active transport
Process in which molecules move against conc gradient
i.e Na-K pump
External energy required (Using ATP)
Osmotic Pressure
Amount of pressure required to stop somotic flow of water
determined by conc of solutes in solution
Osmolality
High osmolality = highly conc (lots of solute in a persons blood)
How does hypotonic solutions act on cells
Hypotonic to conc of cell
Water is going to make the cell less conc by flowing to where conc is higher to equalize conc.
Cell expands
How does hypotonic solutions act on cells
sucking fluid out of them
Hydrostatic pressure
Force within a fluid compartment
BP generated by contraction of heart
Major force that pushes water out of vascular system at capillary level
Difference in BP at arteriole side vs venous side
40mmhg vs 10 mmhg
Oncotic Pressure
Osmotic pressure exerted by colliod (or proteins in solution)
Colloidal osmotoic pressure)
Protein is a major colloid (i.e. albumin)
The colloids in the bloodstream pull in water as it travels towards the solute
Decreased plasma albumin effect on fluid
Extracellular fluid volume excess and consequiential edema
Because colliod oncotic pressure inside capillery has decreased
Normal albumin pulls water back into vascular beds at venouse end
Low colliodal oncotic pressure does not exert that pull resulting in low fluid in vascular space and hihg fluid remaining in tissues
What prevents proteins from diffusing out of the blood stream?
Large molecular size
AMount and direction of fluid movement in capilleries is determined by
Capillary hydrostatic pressure
Plasma oncotic pressure
Interstitial hydrostatic pressure
Interstitial oncotic pressure
Typically which pressures are responsible for causing the movement OUT of capilleries
Cap hydrostatic pressure
Interstitial oncotic pressure
What causes the movemento f fulid into the capilleries
Plasma onctotic pressure
interstitial hydrostatic pressure
Pressure/fluid shift at the arteriole end of cap bed
Capillary hydrostatic pressure exceeds
plasma oncotitc pressure and fluid is moved into the interstition
At venous end of capillery bed, pressure/fluid shift
Capillery hydrostatic pressure is lower than plasma oncotic pressure, and fluid is drawn into capillery by Oncotic pressure created by plasma proteins
Hydrostatic pressure is a _______ (direction) pressure
Push
Oncotic pressure is a ______ (diretion) pressure
Pull
Second spacing
When fluids are shifting out of vascular space into adjacent space (periph edema)
Third spacing
Fluid moving out of intravasc, lymph is unable to compensate, fluid becomes trapped in body spaces
Pleural cavity
Peritoneal cavidty
Pericardial sac
Cannot diffuse back easily
Risk of intravascular fluid volume deficit
with signs of dehydration when TOO much fluid shifts into 3rd spcace
Regulation of water balance (7)
Hypothalamic regulation
Pituitary regulation
Adrenal cortical regulation
Renal regulation
Cardiac regulation
Gastrointestinal regulation
Insensible water loss
Hypothalamic Regulartion
Osmoreceptors in hypothalamus sense fluid deficit or increase
- stim thirst and ADH release
result in increased free water and decreased plasma osmolality
When plasma osmolality normalized, secretion of ADH is suppressed and urinary excretion restored
Pit regulation
Under control of hypothalamus, posterior pituitary releases ADH
Stress, nausea, nicotine, and morphine also stimulate ADH release
ADH impacts -_____ reabsorption in kidneys
Water only, not electrolytes
Most naturally occuring glucocorticoid
Cortisol
Adrenal cortical regulation
Releases hormones to regulate water and electrolytes
Glucocorticoids (ie cortisol)
Anti-inflam effect; increase glucose (during stress)
Mineralocorticoids (ie aldosterone)
Enhance Na+ retention
Enhance K+ excretion
Most naturally occurin mineralcorticoid
Aldosterone
Aldosterone does what
Increases sodium and water retention
In RCT
Decreases osmolarity to decrease and fluid volume to be solved
Renal regulation
Kidneys are primary organs for regulating fluid and electrolyte balance
Adjust urine volume
Selective reabsorption of water and electrolytes
Renal tubules are sites of action of ADH and aldosterone
Glucocorticoids
Anti-inflam effect;increase glucose level
Mineralocorticoids
Enchanccce sodium retention
Enhance potassium excretion
Inversely proportional
ADH
Antidiuretic hormone (ADH)- decreased blood volume stimulates release by the pituitary gland which makes the distal tubule and collecting ducts permeable to water allowing it to be absorbed by capillaries and returned to circulation.
Cardiac regulation of fluid electrolyte balance
Atrial natriuretic factor (ANF)
Hormone released by the cardiac atria in response to atrial pressure ( volume)
Primary actions of ANF are vasodilation and urinary excretion of sodium and water, which decrease blood volume
GI Regulation
Oral intake accounts for most water intake
Most water is excreted by kidneys
Small amounts of water are eliminated by gastrointestinal tract in feces
Diarrhea and vomiting can lead to significant fluid and electrolyte loss
Insensible water loss
Invisible vaporization from lungs and skin to regulate body temperature
Approximately 900 mL/day is lost
No electrolytes are lost
Sodium is a _______ and plays a major role in
Cation
Generation and transmission of nerve impulses and muscle contractions
Maintains fluid balance
Regulates blood pressure
Where is most of body sodium found
in blood and in extracellular fluid
Hypernatremia
Elevated serum sodium occurring with water loss or sodium gain
Causes hyperosmolality leading to cellular dehydration
Primary protection is thirst from hypothalamus
Sodium intake in excess of water intake can lead to hypernatremia
Hypernatremia secondary to water deficiency is usually a result of
Cognitive impairments, level of consciousness or altered baroreceptors (older person
Manifestations of of hypernatremia
Increased thirst
Lethargy
Agitation
Seizures
Coma
Wt Loss (water loss) or gain
Impair LOC
When trating hypernatremia
Serum sodium levles must be reduce gradually to aavoid cerebral edema
Hyponatremia manifestations
Confusion
N/V
seizures
Coma
Hyponatremia
Resulting from loss of sodium containing fluids from water excess
causes hypoosmolality with shift of water into cells (swollen cells)
Causes Hyponatremia
Diuretics (Excretes K and Na)
V/D
Nasogastric suctioning
Burns
Water retention (High levels of ADH)
- Stress or meds)
CHF
Liver dx
Liver Failure
Hormone imbalances
Causes of hypernatremia
Excessive IV fluid with saline
IV fluid with Bicarb
Severe water loss (heat stroke)
Osmotic diarresis
Diabetic insibidis (Anything afffecting RAAS)
Collab care of Hyponatremia
Fluid restriction
IV Hypertonic Saline
Monitor daily wt
Monitor I&O and CNS changes
Don’t act quickly unless emergency
Collab of care of Hypernatremia
Treat underlying cause
Give PO or IV fluid replacement (dillute slowly)
Diuretics possibly
Dietary Sodium restriction
Monitering I and O
Monitor CNS changes
Hypovolemia caused
Diareahh
Fistual drainage, hemmorahge, inadequate intake, or palsma-to interstitial shift, blood loss, fever, diaphoresis, hyperglycemia, GI suction
Dxs
Meds (diuretics)
Third space fluid shifts
Burns
Hyperventiliation
Hypovolemia is a condition of
the intravascular space
The most accurate measurement of fluid status
Wt
Manifestations of hypovolemia
Decreased wt
Decreased urine output, increased specific gravity
Decrease in BP (Posutral hypotenion) and increase Pulse
Dry mucous membranes
Sunken eyes
Apprehension, restlessness
Evidence in lab values
Thirst is not an accurate indication
Postural HOTN is
Systolic drop of 20
Diastolic of 10 or more
When changing positions
IOndications of hypovolemius
how to take postural VS
VS while laying down
Wait 2 mins
VS while sitting up
wait 2 min
VS while standing
Hypovomeia treatments
Address problem
Rehydraiton (PO, tube, IV)
Oral mouth care
Ensure safety (Fall risk) - freq VS
Urine output, cap refill, wt changes, JVD, monitor I&O
Asssessing for 3rd spacing
WHich pts to be extra mindful of
Pts with heart, lung, kidney, or liver dxs
Cannot tolerate large amount of sodium or fluid
Hyperrvolemia Causes
Circ problems
CHF etc,
Renal disorders, lymp obstructions
Liver: Third spacing etc.
Hypervolemia manifestations
Fluid in alveolar sacs - dyspnea, coughing, crackles, hypoxia
JVD, increase BP, Wt gain, periph edema, bounding pulses
Confusion, headache, lethargic, seizure, coma
Decrease sodium, decrease BUN etc.
Interventions from hypervolemia
SOdium restriction
diuretics
BIPAP - oxygenation forcing fluid to shift out of lungs into vascular space
Facilitar oxygenation
decrease Cardiac workload
Sodium volume imbalances nursing monitoring
I&O
Monitor for CV changes
Assessing resp status
Daily wt
Skin assessment
Potassium necessry for
Transmission and conduction of nerve impulses
Maintenance of cardiac rhythms
Skeletal & smooth muscle contraction
Acid–base balance
Normal K values
3.5-5mmol/L
K and Na have what kind of relationship
Inverse
Factors causing sodium retention will cause K excretion and vis versa
Most of K is eliminated by
Kidneys
The more common diuretics spare potassium T or F?
F, most do not
Kidneys ability to conserve potassium is strong or weak>
Weak
Hyperkalemia caused by
renal failure
Massive intake
Shift from intracellurl fluid to extracellular fluid (i.e. DKA)
Massive cell destruction (burns)
Catabolic state (i.e.severe infections)
Transfusion of aged blood
Manifestations of hyperkalemia
Weak or paralyzed skeletal muscles
VFib or cardiacsability b=oriblems
Biggest concern with HyperK
Heart dysrythmias
Stat ECG
hypoK caused by
NOrmal losses of kidnye/GI
Shift from extracellur fluid to intracellular
Inadequate intake
Diuretic use
Magnessium deficiency
Metalbolic aklalosis
Hypoklemia manifestations
Most serious are cardiac
Skeletal muscle weakness & paralysis
Muscle cramping & muscle cell breakdown
Decreased GI motility (paralytic ileus)
Diuresis
Hyperglycemia
How do we give K supplements
Carefully
Venous irritant
Must also be diluted, NEVER given IV push, also done with a pump
What happens when someone cannot get back to homeostasis on their own
Hospitalized when the body cannot return itself to the homeostatic state using internal processes
Anticipating as a part of a nurses role
Nurses need to notice abnormalities, trends and signs and symptoms that problems might be occuring, and then we need to intervene while we can reverse it
excess fluid to children?
Cause cause cerebral edema and death - be VERY careful
Fluid primaraily shifts bw
Intracellular (2/3) and extracellular (1/3); plasma and interstitial
Natural electolyte movement across semi-permiable membrane from high to low conc
Passive transport
Glucose moving across membrane using carrier proteins, still no energy
Facilitated diffusion
Ateriole walls vs venous
Arterioles are thicker, more flexible, more muscular
Higher pressure push gradient in arteries
- Hydrostatic pressure (Push pressure)
Venous experiences higher oncontic pressure (Pull)
Oncontic is a fancy word for
Protein
Pull Pressure
Albumin is most voluminous plasma protein
Why do albumin stay in vascular system
Maintain certain amount of blood pressure, too big to leave vessels
What would low albumin s/s be
Instead of oncotic pressure being 25 mmHg, it is less (i.e. 12 mmHg)
Hydrostatic pressure remains high in arterioles, Pull pressure remains low in arterioles, therefore, fluid remains in interstitial space (Causing edema)
How is low albumin treated
Suplement albumin
- Increasing Oncotic pressure
Compression to INCREASE interstitial hydrostatic pressure (Push pressure INTO vascular space)
Fluid shift into adjacent tissues or adjacent vascular space is called
2nd spacing
Not useful to the body
- Remains availble to the body through therapy
Fluid moving into transcellular space
3rd spacing
Trapped in space, requiring therapeutic removal
i.e. Fluid trapped in abdomen (Asitis)
- CANNOT be pushed back into vascular space once it’s there (not by diuretics)
Must be drained externally (i.e. pericentisis, pleural centisis)
What to decide when fluid is trapped in 3rd space
How much is it compromising bodily functions
Nursing assessment and interventions for 3rd spacing
Assess for signs and symptoms of shock & intravascular fluid volume deficit (ie tachycardia, hypotension, postural vitals)
Monitor urinary output
Monitor electrolytes imbalance
Monitor fluid balance: daily weights & abdominal girth (if ascites). Discuss daily weights
Provide fluids and/or IV albumin as ordered
Assess for intravascular hypervolemia & hypokalemia when third space fluids decrease
Shock is a state where
Advanced state where the critical organs are no longer receiving adequate perfusion
Pts will not live long in that state
Classic s/s of shock
HOTN (Less than 90 or MAP less than 65)
Hypovolemic shock
Tachycardia
HOTN (Below 90 sys, below 65 MAP)
Altered LOC
Can edema coincide with intervascular dehydration (HOTN)
Yes, fluid is in space where it is unusable
Assessing intervascular volume
Feeling pulse (thready vs bounding)
BP
Urine output
Pts lose radial pulse when?
Systolic below 80
Regulation of water balance (7 mechs)
Hypothalamic regulation (thirst)
Pit regulation (releases ADH)
- Less pee
Adrenal Cortical regulation
- RAAS (Aldosterone = Na and water retention)
Cardiac regulation (ANF released by atria)
- During volume overload, causes Na and water release. ALSO vasodialtion
GI regulation
Insensible Water loss (900mLs through ADLs)
Inflammation of GI tract
Decreased reabsorption of water, therefore so much water and electrolytes lost through diarrhea
Sodium is a
Cation and plays a major role in maintaining the concentration and volume of the blood.
Hypernatremia occuring by
Water loss or sodium gain
Primary protection from hypernatremia is
Thirst
Why do corrections of low sodium or high need to be done slow
Because water is affected, and fluid shifts have LARGE impacts on the brain
Must prevent cerebral edema
CP7
Chemical Panel 7
