Fluid Imbalances- Exam 1 Flashcards
5 uses of water in the body:
- Metabolic reactions
- Transport
- Lubricant
- Insulator
- Body temperature
How do healthy people gain fluids?
eating and drinking
Daily intake and output of water should be what in healthy people?
Roughly equal
What is the urine output formula for healthy kidneys?
1 mL/kg/hr
A patient presents with .4 mL/kg/hr output- what does this indicate?
Decreased output - decreased kidney function
How does the body lose fluid?
Kidneys, lungs, skin, GI tract
How does the skin lose fluids?
Sweating, fever, exercise, and burns
How much fluid do the lungs excrete per day on average?
300 mL
5 factors affecting water balance in the body:
- Age
- Sex
- Body habitus (body build)
- Temperature
- Disease state
Increased fat = ______ fluid
decreased
Increased muscle = ___________ fluid
increased
Fluid deficit may cause ? in older adults
delirium
Approximately __% of a typical adult is fluid
60%
Definition - fluid in cells
intracellular fluid
intracellular fluid makes up how much of the fluid in the body
2/3
Definition - fluid outside the cells
extracellular fluid
Examples of intravascular fluid
plasma, erythrocytes, leukocytes, thrombocytes
Example of interstitial fluid
lymph
examples of transcellular fluid
cerebrospinal, pericardial, and synovial
intracellular fluid makes up __% of body weight
40%
extracellular fluid makes up __% of body weight
20%
Normal serum level range in body osmolality
280-295 mOsm/kg
Normal osmolality urine range:
100-1300 mOsm/kg
Describe an isotonic solution
Fluids with the same osmolality
Describe a hypotonic solution
Solutes are less concentrated than the cells
Describe a hypertonic solution
solutes are more concentrated than the cells
How does an isotonic solution affect the movement of water
there is no net movement of water
How does a hypotonic solution affect the movement of water?
Moves water into the cells
How does a hypertonic solution affect the movement of water?
moves water out of the cells
Water moves from an area of low solute concentration to a high solute concentration
Osmosis
During osmosis, the movement of fluid through capillary walls depends on what?
Hydrostatic pressure and osmotic pressure
the pressure that is exerted on walls of blood vessels
Hydrostatic pressur
The pressure exerted by proteins in plasma (solutes)
osmotic pressure
In osmosis, the direction of fluid movement depends on what?
Differences in hydrostatic and osmotic pressure
Does osmosis allow solutes to cross the membrane?
No, fluid only
Blood pressure generated by heart contraction is known as?
Hydrostatic pressure
Where does hydrostatic pressure push water from and to?
Pushes water from the vascular system into the interstitial space
What does hydrostatic pressure prevent?
Prevents fluids from moving back into the vascular spaces
What protein molecule attracts water into the vascular spaces during osmosis?
Albumin
Administering colloids or hypertonic solutions ________ osmotic pressure and draws fluid from _______ ________ into plasma
increases
interstitial spaces
Fluid shifts from plasma spaces to interstitial spaces due to:
- increase in venous hydrostatic pressure
- increase in interstitial oncotic pressure (increased solutes)
- decrease in plasma oncotic pressure (decreased solutes)
How do you decrease interstitial shifts?
Reducing venous hydrostatic pressure (decreased BP) by drawing interstitial fluid into plasma or administer colloids, mannitol, or hypertonic solutions
OR
increase tissue hydrostatic pressure by wearing TED hose or administer diuretics
Normal distribution of fluid spacing is called
First spacing
Abnormal accumulation of interstitial fluid (edema) is called
Second spacing
Fluid trapped where it is difficult or impossible for it to move back into the cells (ascites)
Third spacing
What is the primary organ that regulates fluids and electrolyte balances?
Kidneys
Renal tubules are the sites of action for which hormones?
ADH and aldosterone
Where is the site of action for ADH and aldosterone?
Renal tubules
What receptors sense changes in body fluids? Where in the brain are these receptors located?
Osmoreceptors are located in the hypothalamus
Fluid deficit leads to ______ plasma osmolality
increased
Fluid excess leads to ______ plasma osmolality
decreased
Fluid deficit does what to thirst and ADH in osmosis?
stimulates thirst and triggers release of ADH
Fluid excess does what to ADH?
suppresses the release of ADH
How does the adrenal cortical regulation of fluid work?
Releases hormones to regulate water and electrolytes
What hormones are involved in the adrenal cortical fluid regulation process?
Glucocorticoids (cortisol) and mineralocorticoids (adosterone)
Aldosterone causes retention of what electrolyte?
Sodium
Aldosterone causes excretion of what electrolyte?
potassium
What is retained with sodium?
Water
Kidneys secrete what when they sense low blood volume, BP, or sodium
renin
If a patient’s mean arterial pressure is <60, what does this indicate?
decreased perfusion
Why are ACE inhibitors given to a patient with fluid imbalances?
Disrupt RAAS by reducing amount of ACE produced leading to less vasoconstriction and reduced peripheral resistance.
Blocking angiotensin II receptors leads to lower BP
Give one example of an ACE inhibitor
Lisinopril
Natriuretic peptides are ________ to the RAAS
antagonists
What causes ANP and BNP to be produced?
increased atrial pressures and/or high sodium levels
How do ANP and BNP affect water balance cardiac regulation?
They suppress secretion of aldosterone, renin, and ADH to promote excretion of Na and H2O to decrease BP and volume
What hormones do ANP & BNP effect?
Aldosterone, renin, ADH
Approximately how many mLs of fluid is lost through the GI tract per day?
200 mL/day through stool
3 types of fluid imbalances
Dehydration
FVD
FVE
FVE = ?
FVD = ?
Fluid volume excess
Fluid volume deficit
FVD is also known as
hypovolemia
FVE is also known as
hypervolemia
True or False?
Dehydration is the same as fluid volume deficit
False
Loss of water alone with increase serum sodium levels
dehydration
Pure water loss is common in:
Elderly
Children
Confused
Overexertion
Mild dehydration is corrected by?
Oral consumption
Extracellular fluid loss exceeds intake ratio of water
FVD
Possible causes of FVD
- abnormal fluid losses (V/D, sweating GI suctioning)
- decreased intake (N, lack of access to fluid)
-third space fluid shifts (burns, ascites)
-diabetes insipidus
-adrenal insufficiency
-hemorrhage
-trauma
Isotonic expansion of the ECF caused by the abnormal retention of water and sodium
FVE
FVE is secondary to increase in what content in the body?
total body sodium content
Possible causes of hypervolemia:
-HF
-AKI or kidney failure
-Liver failure
-Excessive IV solutions or transfusions
-Excessive oral sodium intake
-Abnormal retention of fluids/sodium
-Interstitial to plasma fluid shifts
Colloids stay where in the body?
vascular spaces
Give examples of colloids
human plasma products like albumin, blood
semisynthetics like dextran and starches
Colloids are sometimes referred to as
volume or plasma expanders
True or False
Colloids are considered hypertonic
True
parenteral fluid solutions with small molecules which can move around easily when injected into the body
Crystalloids
True or False
Crystalloids are considered hypotonic ONLY
False
Crystalloids can be isotonic, hypotonic, or hypertonic
Types of fluids categorized by tonicity
Hypotonic
Isotonic
Hypertonic
True or False
Lactated ringers are considered isotonic
True
True or False
0.9% NaCl is considered hypertonic
False - it is isotonic
True or False
0.45% NaCl is considered isotonic
False - hypotonic
True or False
3% NaCl is considered hypertonic
True
True or False
5% dextrose in water is considered to be hypotonic
False - it is considered BOTH isotonic and hypotonic
What is the purpose of giving colloids to a patient?
Increase osmotic pressure (BP), and pulls fluid into vascular spaces
What is the purpose of giving a patient crystalloids?
Maintenance (pt can’t eat or drink) or replacement of fluids
Decreased osmolality = _____ tonicity
decreased
100 mOsm/L is what type of solution?
Hypo
Hypotonic solutions contain more what than electrolytes?
Water
Never inject what into a vein?
Why?
Sterile water without additives
It will lyse the cell
Hypotonic solutions move water from ECF to ICF by what?
Osmosis
Hypotonic solutions move water from ___ to ___
ECF to ICF
When administering hypotonic solutions, what should the nurse monitor for?
Changes in mentation
If osmolality is 275-308 mOsm/L - what type of solution is it?
Isotonic
Isotonic solutions are similar to what in the body?
the bloodstream
Isotonic solutions effects ECF how?
Expands ECF only - there is no net loss or gain from ICF
What solution is ideal to replace ECF volume deficit?
Isotonic
What type of solution initially expands and raises the osmolality of ECF?
hypertonic
What solution decreases osmolality and tonicity?
Hypotonic
When administering hypertonic solutions, what should the nurse monitor?
BP changes
Lung sounds
Serum sodium levels