Fluids, Electrolytes, & acid-base Flashcards
What is the plasma volume of a 70-kg male?
a. 3 L
b. 5 L
c. 7 L
d. 9 L
a. 3 L
TBW in an adult is
42 L
How much of total body weight is intracellular volume?
40% or 28 L
What are the major ions of intracellular volume?
K+, Mg2+, phosphate
How much of total body weight is extracellular volume?
20% or 14 L
What are the major ions of extracellular volume?
Na+, Ca+, Cl-, HCO3-
How much of total body weight does interstital fluid make up?
16% or 11 L
How much of total body weight does plasma fluid make up?
4% or 3 L
_______- have the highest TBW.
Neonates
The following have the lowest total body weight:
females
the elderly
obese
_________ dictates the passive exchange of water between the capillaries and the interstitial fluid.
Starling forces
_____________ forms a protective layer on the interior wall of the blood vessel. Disruption of this contributes to ____________
endothelial glycocalyx; capillary leak
The _____________ is a fluid scavenger that removes fluid, protein, bacteria, and debris that has entered the interstitium
Lymphatic system
Edema occurs when the rate
of interstitial fluid accumulation exceeds the rate of removal by the lymphatic system
What is the rule of total body water?
60/40/20 (15/5)
60%- water represents 60% of total body weight
40% of TBW is intracellular fluid
20% is extracellular fluid
15% is interstitial fluid
5% is plasma fluid
Forces that move fluid from the capillary to the interstitial space include
capillary hydrostatic pressure
interstitial oncotic pressure
Forces that move fluid from the interstitial space into the capillary include
interstitial hydrostatic pressure
capillary oncotic pressure
Conditions that impair the integrity of the glycocalyx include
sepsis
ischemia
DM
major vascular surgery
Blood volume is the sums of
plasma volume and blood cell volume
The hematocrit is the fraction of blood volume that is occupied by
erythrocytes
Hematocrit is increased by
an increased number of RBCs or a decreased plasma volume (hypovolemia)
Fluid that accumulates in a potential space is called
an effusion
The movement of water across a semipermeable membrane is
osmosis
The number of osmoles per kilogram of solution is
osmolality
The number of osmoles per liter of solution is
osmolarity
The pressure of a solution against a semipermeable membrane that prevents water from diffusing across that membrane is
osmotic pressure
Water travels from areas of ________- to areas of ____________
lower solute concentration to areas of higher solute concentration
____________ is the net movement of a substance from an area of higher concentration to an area of lower concentration across a fully permeable membrane
Diffusion
Osmotic pressure is NOT a function of
their molecular weights
________ is the number of osmotically active particles in a solution
An osmole
Calculate the plasma osmolarity.
Sodium= 150 mEq/L
Glucose= 108 g/dL
BUN 14 mg/dL
311 mOsm/L
Plasma osmolarity= (Na+ x 2) + (glucose/18) + (BUN/2.8)
Normal plasma osmolarity is
280-290 mOsm/L
The most important determinant of plasma osmolarity is
sodium
Conditions that increase osmolarity include
hypernatremia
hyperglycemia
uremia
What is the equation to calculate plasma osmolarity?
Plasma osmolarity= 2[Na+] + glucose/18 + BUN/2.8
Rank the tonicity for each fluid from highest to lowest:
NaCl 3%
D5W
D5 + NaCl 0.45%
Albumin 5%
NaCl 3%, D5 + NaCl 0.45%, Albumin 5%, D5W
__________ solutions have an osmolarity lower than the plasma
hypotonic
__________ solutions have an osmolarity roughly equal to the plasma
Isotonic
____________ solutions have an osmolarity higher than the plasma
Hypertonic
Tonicity compares the
osmolarity of a solution relative to the osmolarity of the plasma
Hypotonic solutions will cause the cell to
swell
Hypertonic solutions will cause the cell to
shrink
Examples of hypotonic solutions include
NaCl 0.45%
D5W
Examples of isotonic solutions include
NaCl 0.9%
LR
plasmalyte A
albumin 5%
voluven 6%
hespan 6%
Examples of hypertonic solutions include
NaCl 3%
D5 NaCl 0.9%
D5 NaCl 0.45%
D5 LR
Dextran 10%
NaCl can cause ___________ if it is given in large amounts
hyperchloremic metabolic acidosis
