Fluids + Electrolytes Pt 1 Flashcards
Homeostasis
Volume + composition of each space remains constant
What can impact homeostasis?
- vomiting
- diarrhea
- ace inhibitors
- diuretics
Amount of plasma in the body
- Plasma: 3L
- Interstitial fluid (IF): 10L
- Intracellular fluid (ICF): 28L
Composition of body fluids
-Water
- Primary component of body
- Accounts for approx 60% of body wt
- Adequate balance is necessary for
-maintenance of temp
-elimination of waste products
-all transportation within body
Factors that affect body water
Age is a huge factor:
* neonates are made of 80% water
* older adults are made of 45% water
Other factors that influence body water:
* The more adipose tissue the less body water you have.
* The more muscle mass you have the more body water you have.
Composition of body fluids
-Solutes
- Electrolytes: Chemical compounds that develop an ionic charge when dissolved in water
- All body fluids contain electrolytes
Regulation of electrolyte levels is critical for:
- maintenance of body fluid osmolality
- acid balance
- neuromuscular function
- cell metabolism
Composition of body fluids
-Nonelectrolytes
- do not dissociate in solution
- measured by wt
- Glucose - Urea - Creatinine - Bilirubin - Proteins
Body fluid compartment
-Transcellular fluids (not subject to significant gains or losses)
- CSF
- GI tract
- Pleural
- Synovial
- Peritoneal
First spacing?
Normal distribution of fluid
Second spacing?
Abnormal accumulation of interstitial fluid
Third spacing?
- Abnormal accumulation in areas that have no or little amt of fluid
- Fluid unavailable for use
Movement of body fluids
-What is it?
- Fluid constantly moves among intracellular, interstitial and vascular spaces to maintain body fluid balance
- Moves through permeable membranes
-permits movement of water + some solutes - Normally ICF + ECF are isotonic w/ each other
Osmosis?
- Osmosis stops when equilibrium is reached
- Major force in body fluid movement
- Important to consider w/ IV therapy
Movement of body fluids
-Osmotic pressure
- Refers to pulling power of a solution for water
- The higher the osmolality of a solution greater pulling power for water
Movement of body fluids
-Oncotic pressure
Refers to pulling force exerted by colloids
Movement of body fluids
-Diffusion
Solute moves from area of higher concentration to area of lower concentration until equilibrium.
“coasting downhill”
Movement of body fluids
-Facilitated diffusion
Facilitated diffusion is the diffusion of solutes through transport proteins in the plasma membrane.
Facilitated diffusion is a type of passive transport.
Even though facilitated diffusion involves transport proteins, it is still passive transport b/c the solute is moving down the concentration gradient.
Movement of body fluids
-Filtration
- Movement of fluids + solutes from an area of high hydrostatic pressure to an area of low hydrostatic pressure into or out of the capillary
- Dependent on forces favoring filtration + opposing it
- Think of as a tug of war - pushing and pulling
Net filtration
-Forces favoring filtration
- Capillary hydrostatic pressure (blood pressure)
- Interstitial oncotic pressure (water-pulling)
Net filtration
-Forces favoring reabsorption
- Plasma oncotic pressure (water-pulling)
- Interstitial hydrostatic pressure
Fluid shifts
-What is it?
Interstitial fluid to plasma
* Fluid drawn into plasma space whenever there is space increase in plasma osmotic or oncotic pressure
* Wearing of compression stockings or hose is a therapeutic action on this effect
Movement of body fluids
-Active transport
- Movement of solute from an area of lower solute concentration to an area of higher solute concentration
- Depends on ATP
- Example: Sodium-Potassium pump
“pumping uphill”
Renin-Angiotensin
-How does it work?
1-Blood flow to glomerulus drops + juxtaglomeruluar cells secrete renin into bloodstream
2-Renin travels to liver
3-Renin converts angiotensinogen in liver to angiotensin I
4-Angeiotensin I travles to lungs
5-Angiotensin I converted in lungs into angiotensin II
6-Angiotensin II travels to adrenal glands
7-Angiotensin II stimulates adrenal glands to produce aldosterone
Aldosterone
-How does it work?
1-Angiotensin II stimulates adrenal glands to release aldosterone
2-Aldosterone causes kidneys to retain sodium + water
3-Sodium + water retention leads to increases in fluid vol + sodium levels
Factors affecting aldosterone
secretion
- decreased renal perfusion (e.g., decreased plasma volume) stimulates increased renin secretion leading to increased plasma angiotensin II
- increased serum K+
- decreased serum Na+
- stress, physical trauma leading to increased ACTH
Regulation of
body fluids
-Antidiuretic
Hormone (ADH)
- Hormone synthesized by hypothalamus
- Secreted by posterior pituitary
How ADH works
1-Low blood vol + increased serum osmality are sensed by hypothalamus, which signals pituitary gland
2-Pituitary gland secretes ADH into bloodstream
3-ADH causes kidneys to retain water
4-Water retention boosts blood vol + decreases serum osmolality
Regulation of
body fluids
-Thirst mechanism
- Stimulated by thirst receptors in hypothalamus
- Primary protection against hyperosmolality
- Normally occurs w/ even small fluid losses
- Stimulates release of ADH and aldosterone
- Depressed in older people
Regulations of body fluids
-Atrial Natriuretic Peptide (ANP)
- hormone secreted from cardiac cells of the atria in response to stretch of atria from hypervolemia as well as hypertension
- when blood sodium levels + pressure increases, ANP is secreted from the heart, binds to kidney + blood vessels to promote salt excretion/low blood volume/relaxation of vessel
One liter of
water weighs?
2.2 lbs/1 kg
Fluid gains
- Oxidative metabolism = approx 300 ml/day gained
- Oral fluids = 1100-1400 ml consumed daily
- Solid foods = 800-1000 ml/day
- Fluid therapy = varied
Fluid losses
- Kidneys: Primary regulators of fluid and electrolyte balance = approx 1500 ml urine excreted/day
- Skin = ave of 500-600 mL of sensible & insensible fluid lost via skin each day (Can be as great as 2 L/hr)
- Lungs = approx 400 mL insensible fluid
- GI tract = 100-200 mL
- Abnormal losses = varied
- Third space losses = unavailable
Fluid Volume Excess
-Causes
- Renal Disease
- Too rapid infusion of IV fluids
- Steroid Therapy
- Production of ADH
- Cardiac Disease
Brawny Edema
- Fluid can no longer be displaced secondary to excessive interstitial fluid accumulation
- No pitting
- Tissue palpates as firm or hard
- Skin surface=shiny/warm/moist
Fluid Volume Deficit
-Causes
- NPO
- drains
- surgery
- blood loss
- fluid loss from GI tract
- profuse sweating
- polyuria
- fever
- third spacing
- decreased intake
Nurs assessment
-Nursing hx
Dz or disorders that may cause disturbances
Nurs assessment
-V/S
- body temp
- RR and depth
- HR/pulses
- BP
Nurs assessment
-I&O
- Incl all oral, IV fluid intake
- Incl all output, inclg drains, bleeding (may need to measure linens or chux for accurate output)
Nurs assessment
-Systems assessment
- Integumentary
- Neurologic
- CV
- Pulmonary
- G.I.
- Genitourinary
Laboratory assessment
- Serum osmolality
- Hematocrit
- Urea nitrogen
- Urine osmolality
- Urine specific gravity
Diseases that affect F&E balance?
- Diabetes Mellitus
- Diabetes Insipidus
- SIADH
Nurs Dxs
- Excess fluid volume
- Deficient (hyper/hypotonic) fluid volume
- Fluid volume, risk for imbalance
Nurs interventions
- Reflective of dx
- I&O
- Daily wts
- Fluid replacement
-PO
-enteral
-IV - Fluid restriction
- Meds
