fluid balance Flashcards
how do age gender fat affect fluid balance (amount of body made up of fluid)
inc age-dec boy fluid
men have inc body fluid
overweight people have less fluid % than most people
which parts of the body (tissues have the most water)
o Muscle skin and blood have the highest amount of water
o , body fat=less fluid because fat cells contain little water
what percentage body fluids are intra/extracellular
Intracellular 30 liters
Extracellular 12 liters Interstitial 9 liters Intravascular 3 liters Fluid in body spaces negligible Transcellular spaces
causes of hypervolemia (FVE)
o HF, renal failure, cirrhosis of the liver, consumption of excessive amounts of salt
o Increased ingestion (iatrogenic- d/t incorrect IV)
o Increased retention (cardiac disease)
o Decreased excretion (liver and renal failure)
Causes Increased ingestion iatrogenic Increased retention Cardiac disease Decreased excretion Liver failure Renal failure
s/s hypervolemia FVE
o Clinical manifestations result from the expansion of the ECF and include: generalized edema, distended neck veins, pulmonary edema, dyspnea, cough, SOB, crackles, tachycardia, full bounding pulse, pulse pressure, central venous pressure, increased weight, increased urine output Acute weight gain
ascites CVS symptoms ^BP, ^HR, ^JVP, peripheral edema RS symptoms Pulmonary edema
example of interstitial fluid
Interstitial eg lymph and other fluids that surround the cell
example of transcellular fluid
Transcellular eg CSF, pericardial, synovial, intraocular, pleural
causes of third space fluid shifts
o Third space fluid shifts can occur in pts w severe liver diseases, hypocalcemia, dec iron intake, alcoholism, hypothyroidism, malabsorption, immobility, burns, CA
s/s third spacing
S/S of thrd spacing o Early evi of third space shift is dec in urine output despite adequate intake o Inc HR o Dec BP o Dec central venous pressure o Edema o Inc body weight o Imbalanced I/O
what type of body fluid are elctrolytes meas in
plasma
is an anion or a cation positively charged
what is a example of this that is plentiful
cation
sodium ions
where is sodium most concentrated
in the ECF
major electrolytes in the ICF
potassium
phosphate
what is oncotic pressure
o Oncotic P is the osmotic P exerted by proteins eg albumin
what is the inc in urine output caused by the excretion of substances such as glucose etc called?
o Osmotic diuresis
o Usual daily urine volume in adult is
1-2 litres
how much can an adut sweat in an hour in litres
1 or more
how can water be insensibly lost from a person
perspiration.. Fever and burns inc insensible water loss
o Lungs-approx 300ml of insensible water loss/day
o Gi usually lose 100-200ml daily
what is urine specific gravity
o Urine specific gravity meas kidneys ability to excrete or conserve water (its gravity gets compared to water) it is less specifc than urine osmolality. it can be done using a dipstick. inc glucose or protein in urine can cause a falsely elevated specific gravity
how are dehydration and FVD different
o Dehydration is NOT the same as FVD; dehydration is loss of water with an increase concentration of Na
how are the kidneys involved in fluid regulation
• Kidneys filter 18-L plasma every day and excrete 1-2L fluid
o Role of kidney:
Regulate ECF volume and osmolarity by selective retention and excretion of body fluids
Regulation of usual electrolyte levels in ECF by selective electrolyte retention and excretion
Regulation of pH of the ECF by retention of hydrogen ions
Excretion of metb wastes and toxic substances
how would a heart w dec CO affect water and electrolyte reg
the heart might not circ enough blood to kidneys and not allow for urine formation
how are the lungs involved in fluid balance
• Lungs
o Exhale 300mL of water a day
if hyperpnea (abnormally deep respirations) or continuous coughing then loss will inc
which glands are involved in reg of fluid balance. how?
- Hypothalamus: makes ADH, which is stored in the pituitary gland
- Adrenal Fx: aldosterone secreted by adrenal cortex; sodium (and water) retention, K loss
- Parathyroid: regulate Ca and phosphate and PTH
for interest: what are osmoreceptors
on the surface of hypothalamus. sense changes in sodiu conc. w dehydration they send signal to p. pituitary which rel ADH
creatinine
it the end product of muscle metb.
better inicator of kindy fx than BUN
serum creatinine inc when kidney fx dec
what inc and dec HCT
inc: -dehydration -polycythemia dec: -anemia -overhydration
what is fuid volume deficit
• Fluid Volume Deficit (FVD)/hypovolemia: when loss of ECF volume exceeds the intake of fluid; occurs when h20 and electrolytes are lost in same amounts, so ratio of serum electrolytes remains the same
causes of fluid volume deficit
o Abnormal fluid losses-N+V, diarrhea, GI suctioning, sweating, decreased intake (nausea, lack of access to fluids), third space fluid shifts, movement of fluid from vasculature to other body spaces (edema, ascites), diabetes insipidus, adrenal insufficiency, osmotic diuresis, hemorrhage, coma Causes Reduced intake Increased losses Skin 300-500 Resp 600-800 Urine 1400-1800 Bowel 100
s/s of hypovolvemia
o Acute weight loss, decreased turgor, oliguria, concentrated urine, orthostatic hypotension, weak, rapid heart rate, flattened neck veins, increased temp, thirst, decreased of delayed cap refill, decreased central venous pressure, cool, clammy pale skin r/t peripheral vasoconstriction, anorexia, nausea, lassitude, muscle weakness and cramps
Acute weight loss CVS symptoms low or postural BP, ^HR Thirst Dehydration Poor tissue turgor, dry mucosa, oliguria
lab findings of pt w hypovolemia
Lab findings
o Elevated BUN out of proportion to serum creatinine; ratio is greater than 20:1
Bun elevated bc dehydration or decreased renal perfusion and function
o HCT is greater than normal bc there is decreased plasma volume
o Serum electrolytes changes may exist: K and Na reduced or elevated
o Urine specific gravity is increased in relation to kidneys attempt to conserve water and is decreased w diabetes insipidus
if a pt suffers __________ will they be hyper/hypokalemic
- GI and renal losses
- adrenal insufficiency
gi and renal-hypokalemic
adrenal insuff-hyperkalemia
Tx of hypovolemia
o ID and treat underlying cause
o Consider usual maintenance requirements
o Fluid replacement: isotonic IV solutions (NS, LR)
Must be done quickly to prevent renal damage
o Encourage oral fluid intake
tx of hypervolemia
Identify & treat the cause
Restrict Na+ and fluid diet
Diuretics
Thiazide (ie Hydrochlorothyazide (HTCZ) (mild to moderate FVE) block sodium reabsoprtion in the distal tubule
Loop Diuretics (ie Lasix (Furosemide) (severe FVE) increase loss of water and sodium
Hemodialysis
nursing intervetnions hypervolemia (ppt)
Detecting is of primary importance!!
Accurate Measuring and Accurate Recording
Assess for edema
Rest
Monitor and teach sodium restrictions
Administer diuretics as ordered and monitor
(frequent) Chest Assessment
Vital signs Q4-6H
Elevate legs when sitting
Position for optimal comfort, circulation and respiration
May require IV Albumin
nursing interventions hypovolemia (ppt)
Monitor I&O accurately Daily weight Bowel care prn Skin care Vital signs Parenteral Administration Monitor for fluid overload when replacing fluids Provide excellent mouth care NV/S to monitor LOC NOTE: please attend to the gerontological considerations in Day et al.
fve is always secondary to
o FVE is always secondary to an increase in the total body Na content which, in turn, leads to an increase in total body water
lab findings of hypervolemic pt
• Diagnostics
o BUN and HCT decline bc of plasma dilution
o CXR- pulmonary congestion
bun
o BUN:
Made up of urea (end product of protein metb)
Normal BUN is 3.6-7.2mmol/L
Factors increasing BUN: decreased renal fx, GI bleeding, dehydration, increased protein intake, fever, and sepsis
Factors decreasing BUN: end-stage liver disease, low protein diet, starvation, any condition that results in expanded fluid volume (ie-pregnancy)
where can third spacing take place ppt
• Third Spacing: o Peritoneal cavity (ascites) o Pleural cavity (pleural effusion) Effusion: transudation of fluid into serous cavities o Pericardial sac o Joint spaces (synovial)
how might fluid and electrolyte imbalances present in o adults
mnfts may be subtle or atypical
fluid deficit may present as delirium while the first sign in young pt would be thirst
o adults are much more sensitive to changes in fluid and electrolyte imbalance
where should skin turgor be monitored for o adults
is this the best indicator of hydration
forehead or sternum in older pts
no the skins lost some elasticity. it may be more useful to measure the slowness of filling of the veins int he hands and feet
why might an o adult restrict their fluid intake
theyre afraid of accidents
what could happen w excessive volume of IV fluids to o adult
may produce fluid overload and cariac failure d/t dec cardiac reserve and reduced renal fx
why do o adults dehydrate so fast
dec kidney mass, dec GFR, dec renal blood flow, dec ability to conc urine, dec excretion of potassium, dec of total body fluid
when considering a discharge of an o adult what would you assess to see if they can care for themselves w a fluid imbalance
functional assessment of ability to det fluid and food needs and to obtain adequate intake. eg can they ambuate, swallow, reach things
what would 3% NaCl be used for? 5% NaCl?
3% to treat hyponatremia in critical care situations only as only a small amount is nec to have a large effect on sodium levels
5% is to treat symptomatic hyponatremia
what are hypotonic IV solns used for.
eg
0.45% NaCl
used to treat hypertonic dehydration…
what solutions could you use to treat hypovolemia
isotonic ones to inc ECF volume: Lactated Ringers (has more electrolytes than 0.9% NaCl.
which isotonic solution wouldnt be good when used alone to treat a FVD. why?
D5W. it has no electrolytes and dilutes plasma electrolyte conc
how would aldosterone affect hypervolemia
if it were being chronically stimulated from
- cirrhosis
- heart failure
- nephrotic syndrome
what would be prescribed for severe hypervolemia
eg. why?
loop diuretic
eg furosemide
they block sodium reabsorbtion int he ascending limb of the loop of Hene where 20-30% of sodium is usually reabsorbed (as opposed to thiazide diuretics which prevents only 5-10% reabsorption)
where do thiazide diuretics work?
in the distal tubule. they block sodium reabsorption there . where 5-10% of sodium is reabsorbed
what can result from the use of diuretics
how can this be addressed
electrolyte imbalances. generally hypokalemia unless the drug works in the last distal tubule in which case it can cause hyperkalemia esp if the pt has dec renal fx
take potassium supplement
dec magnesium levels also
maybe hyponatremia
eg of a drug that works in the last distal tubule and what electrolyte problem it causes
spirinolactone could cause hyperkalemia
how would diuresis cause hyponatremia
inc ADH trying to address the dec in circulating blood volume
whats azotemia
inc nitrogen levels in the blood when urea and creatinine arent excreted w FVE d/t dec perfusion by kidneys and dec excretion of wastes
what is the optimum daily amount of sodium
2000mg
when measuring for edema in FVE what ould indicate edema
a diff of 1cm at the ankle and 2cm at the calf
where are the 4 locations measured to assess for peripheral edema
forefoot
smallest and largest circumference of the calf
mid thigh
is activity or rest better to treat hypervolemia
bed rest promotes diuresis
considerations for a hypervolemic pt in bed
semi fowlers if theyre SOB
turn and reposition often if they have edema
what is the main focus of teaching a pt w FVE
about edema. how to recog the S/S
what is anasarca
severe generalized edema
what might a pt w ascites report
SOB and a sense of pressure d/t pressure on diaphragm
hyponatremia causes
Causes
Increased water intake
Reduced water loss
Sodium loss
s/s of hyponatremia
S/S
Lab findings
Na
how would the labs present of a person with hyponatremia
look for hemodilution and low sodium
