Week 5: Fluid and Electrolytes Flashcards
what are some concepts that connect to fluid and electrolytes?
nutrition
mobility
hormonal regulation
cognition
perfusion
gas exchange (with perfusion as well)
acid-base balance
elimination
in previous courses, how did homeostasis connect to fluid and electrolyte balance
- homeostatic mechanisms are in place to maintain optimal fluid balance in a variety of conditions
ex. normal intake - normal output
decreased intake - decreased output
increased intake - increased output
what are the three components that are connected to fluid or water
plasma in our blood vessels aka vascular space
interstitial space: fluid in the space BETWEEN cells
intracellular space: fluid in the space INSIDE the cells
which compartments of fluid has the least amount? the most?
least: plasma
most: intracellular
which two electrolytes do we need to know?
sodium Na+ and Potassium K+
which electrolyte is more prominent in the plasma?
Na+
which electrolyte is more prominent in the intracellular?
K+
true or false: When we draw labs, we can only measure the concentrations of these electrolytes IN the blood, not inside the cells
true
when looking at a lab value, what does normal range of hemoglobin and hematocrit mean?
shows optimal levels of body water present in the blood
what is hemodilution an indicator of?
over hydration, too much fluid in the vascular space (plasma)
hemodilution: what would your labs show up as?
low (not as much salts), increase in fluid in blood, lymph and vascular space
hemoconcentration: what would your labs show up as?
high!!, fluid value is low, too much solutes in blood, lymph and vascular space
true or false: When a gradient exists, water movement through membranes (filtration) occurs until the hydrostatic pressure is the same in both spaces
true
true or false: Water moves through the porous membrane (filters) from the space with higher hydrostatic pressure to the space with lower pressure.
true
is bp an example of hydrostatic filtering force?
yes it is
what is diffusion?
Diffusion is the movement of particles (solute) across a permeable membrane from an area of higher particle concentration to an area of lower particle concentration (down a concentration difference or “gradient”).
how can diffusion be used in clinical practice?
Diffusion transports most electrolytes and other particles through cell membranes.
what is the difference between cell membranes and capillary membranes?
Cell membranes - selective
capillary membranes - not selective
what is one example where diffusion can not help with clinical practice?
GLUCOSE
what is insensible water loss?
no mechanisms control it - water loss occurs through the skin, lungs, and intestinal tract, salivation, drainage from fistulas and drains, and GI suction.
why is aldosterone secreted?
what Na+ levels are low (water is low) and it works to help reabsorb water for the body
does Natriuretic peptides (NPs) create affects that are opposite to aldosterone?
yes
what is the main controller of the ECF potassium level?
sodium-potassium pump, found in all body cells.
This pump moves extra sodium ions from the ICF and moves extra potassium ions from the ECF back into the cell.
true or false: Kidney excretion of potassium is enhanced by aldosterone.
true
is osmolarity another word for plasma concentration?
yes
what it the value when water is deficit? what about when water excess?
deficit - more then 295
excess - less then 285
what are the ICF and the ECF normally?
a) hypertonic
b) isotonic
c) hypotonic
b)
what is hydrostatic pressure? what is oncotic pressure?
hydrostatic pressure: pressure against the vessel towards the tissue, essentially wants to push water out of the cell
oncotic pressure: pressure from the tissue to the vessel (bring it back to the vessel)
when there’s a high hydrostatic pressure and a low oncotic pressure, what can occur?
swelling, when hydrostatic pressure it pushing towards tissue, and the oncotic pressure is not matching - causes pressure on tissue = swelling
what specific part of the body regulates water balance (think brain)
the hypothalamus-pituitary gland
how does the hypothalamus pituitary gland work to regulate water?
contains hypothalamic osmoreceptors - these can detect ex. high osmolality (water loss, too much Na+) and the hypothalamus detects this!!
- trigger thirst
- ADH released by pituitary gland (kidney) - free water reabsorption (no Na+)
difference between ADH and aldosterone?
ADH directly increases how much water is reabsorbed, and aldosterone directly increases how much salt is absorbed (water as well)
how can ADH release be triggered?
increased plasma osmolality, stress, nausea, nicotine, and morphine
What is ADH?
antidiuretic hormone - kidneys reabsorb more water, NOT Na+. This dilutes our blood so the Na+ concentration drops
how does the GI regulate water?
intake: this is a source of new water to the body
output: diarrhea and vomit - excess water loss and electrolyte loss
how does Genitourinary regulate water?
OUTPUT: urine
renal excretion provides LARGEST output
what is insensible water loss
approx. 900 ml per day
water loss from breathing and insensible perspiration (water only)
Excessive sweating (sensible perspiration) may lead to excessive water and electrolyte loss (fever, hot environment)
Water used in metabolic proccesses (GI)
true or false: the trigger of thirst is increased in older adults
false; decreased
what are some age related considerations related to fluid and electrolytes?
there is an increased risk of imbalances
Reduced renal function
Reduced hormone regulation Reduced thirst trigger
Reduced temperature regulation
Impaired functional and cognitive ability may interfere with oral consumption of water
what are some nursing implementations with fluid and electrolytes?
1 intake and output: use a 24hr record of I&O
types of fluid intake - drinking. eating, IV’s, GI tubes
types of output - urine, vomit, diarrhea, sweat, breathing
Accurate daily weight estimates volume status
Rapid increase of 1 kg body weight approximates 1000 mL
(1 L) of fluid retention
Obtained under standardized conditions (same time every day, with the same clothes, same scale)
you have a patient that needs monitoring I&O and you decide to use daily weight measurements via the bed. Last night your patients was complaining that it was cold so you provided her with some blankets. Her average weight is 50 KG but when you measured her today she weighed 55kg via the bed. Would this rapid increase of approx. 5 ml of fluid be a emergency?
most likely not BECAUSE you never removed the blankets! always remember to use the same clothes for accurate measurements via bed
what are some examples of oral intake?
free water - tap water, no significant Na, provide water to dilute plasma Na, if not needed the kidneys will excrete excess water
Electrolyte-replacement beverages (sports drinks, Pedialyte) provide electrolytes commonly lost through sweat, vomiting, diarrhea as well as water
Food and other beverages – most food also contains water!!!
Caffeine beverages may result in increased urine output, can cause dehydration
When a patient cannot swallow fluids/foods – GI tube may be inserted down a nasal passage and into the stomach or small bowel – fluids/liquid food may be instilled through this tube (tube feeds)
what does a fluid volume deficit look like?
decrease intake - normal output (dehydration osmolarity is high)
intake - increased output (diarrhea, vomit)
what does a fluid volume excess look like?
excessive or rapid intake - output (too much water intake/food)
intake - decreased output (unwell kidney)
what is hypernatremia?
high levels of Na+ in the blood
what is hyponatremia?
low levels of Na+ in the blood
what is hypo/hyperaluminemia?
too low/high amounts of albumin(protein) in the blood
what is hypervolemia? what about hypovolemia?
hypervolemia: volume excess
hypovolemia: volume deficit
starts in vessels/blood - then to IF - then in the cells
true or false: Na, Protein and Glucose are all osmotically active and influence the movement of water between compartments (osmotic pressure)
true
what are the three levels of fluid spacing?
First spacing: normal ICF ECF
Second spacing: edema in tissue (too much IF, may cause too much in ICF)
Third spacing: accumulates in body spaces-“potential spaces” - ascites in abdominal cavity, pleural effusion in pleural space, blisters etc NOT ABLE TO MOVE BACK INTO THE PLASMA
what is hypovolemia?
low circulating volume
can occur with loss of normal body fluids (diarrhea, fistula drainage, hemmorage) decrease intake or plasma to interstitial fluid shift (3rd spacing)
Goal: treat cause, replace water and electrolytes give blood if due to herrohage
IV fluids to replace quickly
what is hypervolemia?
High circulating volume
May result from excessive intake of fluids, abnormal retention of fluids (CHF), or interstitial-to-plasma fluid shift
AKA overhydration, fluid volume overload
Goal: remove Na+ & water without causing other electrolyte imbalances
Treat with diuretics & fluid restriction
hypovolemia occurs due to
vomitting diarrhea, suctioning gastric or intestinal fluid, wound drainage, overuse of some diuretic, hemmorhage, massive diaphoresis
what are the clinical manifestations of hypovolemia?
- ↓Weight
- ↓B/P
- weak thready pulse (1+)
- ↑HR(fromSNSresponse-baroreceptors)
trying to maintain CO - Flat neck veins
- Prolonged capillary refill
- Pre-syncope, dizziness or syncope
- ↓blood flow to kidney→RAAS&
Aldosterone - low urine output-oliguria, ↑ urine Specific
Gravity - Slow fluid loss→ ↓tissue turgor (tenting)
- Mucosa dry, tongue furrowed/cracked
- Constipation, hard stools
- Eyes sunken
- If extreme loss of tears and sweating
- Infants may have sunken fontanelle
hypervolemia occurs due to
the opposite… from IV fluid overload (NS, R/L) many pathos that increase aldosterone or cause the kidney to fail and some drugs like corticosteroids
what are the purposes of IV fluids?
to maintain and replace water that have been lost
True or false: Isotonic only expands the ECF
true
are IV’s used frequently?
yes
What do hypotonic IV fluids provide?
provides more water than electrolytes, dilutes the ECF - moves water into cells
what does hypertonic IV fluids provide?
essentially raise the osmolality of ECF and expands it
draws fluid out of cells
used infrequently in special circumstances
can hypertonic iv fluids cause intravascular fluid volume excess and cellular dehydration?
yes
which Iv fluid needs SPECIAL monitoring?
a) hypertonic
b) isotonic
c)hypotonic
a)
what are crystalloids? do they contain proteins?
fluids for IV admin that supply water and electrolytes, NO
what are the further details of crystalloids?
help to maintain osmotic gradient between extravascular and intravascular components
have plasma volume expanding capacity that is related to Na+ concentration
contains fluids and electrolytes that are normally found in the body
are crystalloids better for treating dehydration than for expanding the plasma volume?
yes
crystalloids are used to maintain fluids and
- to compensate for insensible fluid loss
-to replace fluids
-to manage specific fluid and electrolyte disturbances
-to promote urinary flow
what are the three saline solutions under crystalloids - saline?
normal saline - NS 0.9%
0.45% Normal Saline - 1/2 NS (hypotonic)
3% Saline (hypertonic)
what is normal saline - NS 0.9%
isotonic
no calories
slightly more NaCl than ECF
EXPANDS IV fluid
preferred fluid for immediate response
risk for fluid overload higher
DOES NOT change ICF volume
what is 0.45% Normal Saline - 1/2 NS
Hypotonic
Free water, Na+, and Cl-
Promotes movement of water from ECF to ICF
Caution—overuse may lead to cellular swelling!!!!!!!
what is 3% Saline?
Hypertonic
* Caution-must be administered slowly and with extreme caution
* May cause dangerous intravascular volume overload & pulmonary edema
what are the three crystalloid solutions - dextrose?
Dextrose 5% in water - D5W
Dextrose 10% in water - D10W (hypertonic)
Dextrose 5% in 0.45% Normal Saline- D5 1⁄2 NS
what is Dextrose 5% in water - D5W?
Isotonic
Provides 170 kcal/L
Free water-becomes hypotonic
Moves into ICF: caution with ↑Intra Cranial Pressure
moves fluid inside
what is Dextrose 10% in water - D10W ?
- Hypertonic
- Provides 340 kcal/L
- Free water
- Upper limit of dextrose concentration that may be infused peripherally
what is Dextrose 5% in 0.45% Normal Saline- D5 1⁄2 NS ?
hypertonic in the bag - hypotonic in the body
Provides calories! Prevents ketosis (process when body does not have enough cals)
what is Lactated Ringers (LR or RL) - crystalloid
Isotonic
more similar to plasma than NS
Has less NaCl than NS
Has K, Ca, PO4, lactate (metabolized to HCO3)
Expands ECF
Common replacement fluid
used for very sick patients, more electrolytes and acid/base balance
what are Colloids - IV solutions?
also known as plasma expanders
protein substances that INCREASE the colloidal osmotic pressure (COP) and more fluid from the interstitial compartment to the plasma compartment
what would you use to treat this condition: When the protein level in the blood falls, fluid shifts out of the blood vessels & into tissues.
colloids
what are some indications of colloids?
Treat a wide variety of conditions
Are superior to crystalloids in plasma volume expansion but more expensive
what are some contraindications of colloids
Known drug allergy Hypervolemia
Severe electrolyte disturbance, usually an end of life treatment
do colloids help with symptom control(does not fix completely), when they have low albumin?
yes
what are some common colloids?
Dextran 70
Dextran 40
Hetastarch
5% Albumin
25% Albumin
true or false: Albumin is a colloid fluid that can increase the oncotic pressure in the blood
true
true or false: a person with sever dehydration should be treated with normal saline 0.45%
true
The IV fluid known as Lactated Ringer’s expands ECF volume and contains many electrolytes
yes
what is hyponatremia?
low serum sodium
relative excess of H2O in relationship to sodium
serum is more dilute than normal - low osmolarity
low osmolarity causes fluid to shift from plasma to cells (high con. to low)
what are the clinical manifestations of hyponatremia?
Non-specific CNS dysfunction R/T cells (brain cells)
swelling with fluid
Malaise
Anorexia
N & V
Headaches → confusion → lethargy → seizures → coma
Severe swelling in brain → herniation/fatal
what is hypernatremia?
High serum sodium
Relative excess of sodium in relation to water
High Na in the plasma (elevated serum osmolality) ‘pulls’ fluids out of the IF and ICF cells shrink & become dysfunctional
what are the clinical manifestations of hypernatremia?
Again CNS dysfunction but now because of shrinking brain cells
Lethargy → agitation → seizures → coma
Intense Thirst (diminished in elderly)
Oliguria
Severe hypernatremia → death
what is the ethology behind hyponatremia?
Etiology: gaining more water than salt
Diseases that cause too much antidiuretic hormone to be secreted—kidney reabsorbs water & not Na
* SIADH
* Pain, nausea, stressors (common in post-
op patients)
Excessive IV fluids without Na (D5W) or hypotonic solutions 0.45% NS
Excessive water drinking
Meds: diuretics
what is the etiology behind hypernatremia? two ways
- Gain of salt more than water
Highly concentrated tube feeds, hypertonic IV fluids (3% NS), older folks with diminished thirst - Loss of more water than salt
Conditions (Diabetes insipidus): lack of ADH so water is not reabsorbed
Prolonged Vomiting, Diarrhea, diaphoresis
what is the treatment for hypernatremia?
Caused by water loss:
Treat underlying cause
Replace with isotonic fluid like NS 0.9%
Caused by excess sodium:
Treat underlying cause
Replace with salt-free IV solution like D5W
Excrete sodium with diuretics
what is the treatment for hyponatremia?
Caused by Water excess:
Fluid restriction
If seizures can use small amount of Saline 3% to increase sodium (dangerous)
Caused by fluid loss:
IV replacement of fluids containing sodium
what organ does potassium affect the most?
the heart - cardiac!!!
what can you tell me about potassium?
most abundant positively charged electrolyte inside cells
95% of the body’s K+ is intracellular
potassium levels are critical to normal body functions
what are some sources of potassium?
fruit and fruit juices, fish, vegetables, poultry, meats, dairy products
how is excess K removed from the body
via your kidneys!!
can impaired kidney function lead to higher serum levels (K+), toxicity?
yes
what is potassium responsible for?
Potassium is responsible for: Muscle contraction
Transmission of nerve impulses Regulation of heartbeat Maintenance of acid–base balance
Many other functions in the body
what are the 3 major causes of hypokalemia?
- potassium loss
- potassium shift into cells
- lack of potassium intake
what is potassium loss linked to ?
GI loss: diarrhea, vomiting, NG sunction, Diuretics
what is potassium shift into cells linked to?
increased insulin, alkalosis, tissue repair, increase epinephrine (stress)
what is the lack of K+ intake linked to?
starvation
low potassium diet
what are the clinical manifestations of hypokalemia?
early:
* Anorexia
* Hypotension
* Lethargy
* Confusion
* Muscle weakness
* Nausea
late:
* Cardiac dysrhythmias
* Neuropathy
* Paralytic ileus
* Secondary alkalosis
treatment: replace K+
what are the three major causes of Hyperkaemia?
excess potassium intake
-rapid excess IV med admin
-K+ containing drugs
shift out of cells
-Acidiosis
-tissue catabolism(fever, sepsis, burns)
-crush injury
-tumour lysis syndrome
failure to eliminate
Renal disease-most common
K+ sparing diuretics
adrenal insufficency
ACE inhibitors
what are the clinical manifestations of Hyperkalemia?
muscular - weak skeletal muscle, leg cramps/pain
nausea and vomiting and diarrhea
cardiac - EKG changes, Irregular pulse Ventricular fibrillation or cardiac standstill may occur
what does kayexalate do?
it simply helps the body remove excess K+
what is the generic name for Sodium polystyrene sulfonate?
kayexalate
what is the mechanism of action: Sodium polystyrene sulfonate
as resin passes through GI, resin removes K+ ions by exchanging it for Na+ ions. most occurs in large intestine.
is the process of Sodium polystyrene sulfonate fast of slow?
slow, may take hours to days
is Sodium polystyrene sulfonate used to treat hypo or hyperkalemia?
hyper!!
what is two diuretics used to control the kidneys?
Furosemide & Spironolactone
Furosemide is what kind of diuretic?
loop diuretic
what is the mechanism action of Furosemide ( loop diuretic )?
inhibits the sodium potassium pump in ascending loop of henle, decreasing reabsorption of sodium and water
what are the indications of Furosemide ( what do we use it for?)
Edema ( used to treat edema)
Hypertension ( HTN)
contraindications of Furosemide
electrolyte imbalances, hypovolemia
what are side effects of furosemide?
hypotension, hypokalemia, tinnitus
what kind of diuretic is spironolctone
potassium sparing diuretics
what is the mechanism of action of spironolactone
inhibition of water and sodium reabsorption in the kidney while saving potassium
what are the indications of Spironolactone
like furosemide however counteract potassium loss ( may be used with furosemide)
true or false. Spironolactone can be used with Furosemide
true
what are the contraindications of spironolactone
hyperkalemia, hypovolemia
what are the side effects of spironolactone?
hyperkalemeia, hypotension
What are the Diuretic Nursing Considerations?
Monitor BP, weights, UO, labs
EVALUATION AFTER ADMINISTRATION!
ADH dysfunction, what can happen?
hint : there’s two things that can happen
Syndrome of Inappropriate ADH ( SIADH)- excessive ADH secretion
diabetes insipidus ( DI)- lack of ADH secretion
SIADH -what is the pathophysiology?
Recall: ADH released despite low or normal serum osmalility.
causes of SIADH:
malignancies : ADH secreting tumour, pituitary tumour
CNS disorders: meningitis / brain trauma
pulmonary disorders
drugs
SIAH- What are the manifestations?
Fluid retention = decreased urine output and increased body weight
Symptoms are primarily related to decreased Na+
- muscle cramps, twitching, weakness
vomiting, abdominal cramping, anorexia
lethargy, confusion, headache, seizure, coma
SIADH- How is it diagnosed?
stimulatenous measurements of serum and urine osmality
- serum osmolality - decreased
urine ormalility- increased
other lab results
- decreased serum Na
decreased Hemoglobin and hemotocrit
SIADH- what’s should the nurse do?
Choose from the following : ( multi-select)
Monitor for
a. sudden weight gain
b. urine with a decreased concentration
c. change in LOC
d. blood pressure only
a and c
b is wrong, urine decreased does not indicate SIADH, urine with an increased concentration is the one we should monitor
d is wrong: it should not only be. blood pressure but every vital signs should be monitored
What are the treatments for SIADH?
treat underlying cause
fluid retention
diareutics
What are we describing here ?
deceased production or secretion of ADH ( or lack of renal response to ADH) = inability to conserve water
Diabetes Insipidus
What are the two types of Diabetes Insipidus ? and explain what they are
central ( neurogenic ) - interference with ADH synthesis or release
nephrogenic - inadequate renal response to ADH
what is polydipsia?
excessive thrist
what is polyuria ?
urinate more than normal
Would polydipsia and polyuria be an indication of DI?
yes
What are the manifestations for DI
Polydipsia
abrupt polyuria
fatigue
constipation
weight loss
dehydration
decreased LOC, seizures, shock, coma
How is DI diagnosed?
history and physical exam
labs
water deprivation test ( for your interest only)
go into further details in how Di is diagnosed
History and physical exam - may help determine origin
- can be caused by brain trauma, brains surgery so due to damage to the pituitary ( Central DI) or by renal issues ( not responsive to ADH, called nephrogenic DI)
Labs
- urine osmolality /specific gravity is low
serum osmolality - high ( or high normal if compensating well with oral intake)
True or false. When treating DI, treat the primary cause and goal is to maintain fluid and electrolyte balance.
true
What are the two treatments we could specify when it comes to DI?
Central DI
- acute- hypotonic IV saline to replace urine output
- DDAVP ( desmopressin acetate) - hormone replacement due to lack of ADH
Nephrogenic DI
- dietary measures ( low sodium )
- Thiazide diuretics
true or false. Do we treat DI like a hypovolemic person? as they have a change of dying first ?
yes we treat the patient like a hypovolemeic person, ( no volume inside of their body/fluid)
what should u monitor as a nurse when dealing with a DI pateint?
vital signs
measurements of their weight
inoout/output
DI- What is the nurse to do ? Assesment and client teaching
DDAVP - a synthethic version of the ADH. given orally ( doesn’t have to know)
