Fluids and Electrolytes Flashcards
When the dry body weight of a patient is greater than _____% of their IBW, use the nutrition body weight for calculating _____, _________, and _______ parameters.
130%, NBW used for calculating fluid, electrolyte, and nutrition (FEN) parameters
What is the difference between sensible and insensible fluid losses?
Sensible fluid losses are measurable, while insensible losses are not.
What are some examples of sensible and insensible fluid losses?
sensible-urine (400-1500 mL/day), feces (100-200 mL/day), wounds (varies)
insensible-loss from skin and lungs (both 350-400 mL/day)
Name some additional ways we lose fluid that may or may not be measurable.
NG suctioning, vomiting, large wounds, bleeding, fistulas, drains, diarrhea, burns
Osmosis is the movement of _______ and affects the concentration of _______ in the blood.
water, electrolytes
Capillary filtration involves regulation of ______ ______ by the movement of both ______ and ______ through the capillary wall.
blood volume, solutes and fluids
What is the driving force behind capillary filtration?
hydrostatic pressure
Oncotic pressure is driven by what kind of molecule?
protein (albumin, hgb)
Name and describe the effects of the 3 principal hormones involved in volume regulation.
ADH (vasopressin)-reduces diuresis by allowing the insertion of aquaporin channels in the collecting duct, draining water from the urine and concentrating it
RAAS- aldosterone stimulates increased sodium, chloride, and water retention
ANP- released by atria in response to stretching, decreases the effects of ADH and counteracts RAAS system
What range of osmolarity is considered isotonic to human cells?
275-290 mOsm/L
What is the sodium concentration of normal saline? What is its osmolarity in mOsm/L?
154 mEq/L, 308 mOsm/L
What is the modified Holliday Seger equation/what is it used for?
1500 mL + 20 mL for each kg above 20 kg
used for calculating the amount of daily MIVF needed for a particular patient
Using a clinical estimate, how many mL of fluid are given per kg of body weight in an adult patient?
30-40 mL/kg
Describe crystalloid fluids (tonicity and examples).
Crystalloid fluids may be hyper, hypo, or isotonic. Examples include NS, LR, 1/2NS, D5W, and balanced salt solutions.
Describe colloid fluids (tonicity and examples).
Colloid fluids are only ever hypertonic. They are used to draw fluid back into the vasculature, and are known as “plasma expanders”. Examples include albumin, hetastarch, blood, tetra starch, and plasmanate.
What are crystalloid solutions primarily used for?
fluid/salt replacement, maintain the osmotic gradient between vasculature and tissues
Which crystalloid solution is used for free water replacement in dehydration? What other characteristics are unique to this solution?
D5W
NOT to be used as a MIVF by itself and NOT for resuscitation
Which of the crystalloids most closely resembles human plasma and can be used in cases of blood loss?
LR, used for resuscitation
Which of the crystalloids can be used as a maintenance fluid?
1/2NS
What is normal saline’s place in fluid/electrolyte therapy?
used for fluid replacement (resuscitation, hypotension, septic shock)
A balanced salt solution is a crystalloid that contains physiologic levels of _______ and _______.
chloride and buffer
What are some examples of balanced salt solutions?
LR, plasmalyte, normosol
What is the general role of colloid solutions in fluid/electrolyte therapy?
“plasma expander”–pulls fluid from interstitial compartment into the vasculature, useful for volume expansion
Colloids are used as first-line therapy for __________ shock, but second-line for __________ shock.
hemorrhagic (blood is a colloid), hypovolemic