Electrolytes 1- SG Flashcards
1
Q
What labs need to be ordered separately?
A
Magnesium & Phosphate
2
Q
- Total body water is __% of total body weight.
- Intracellular Fluid Compartment (ICF) is ___ of body water
- Extracellular Fluid Compartment (ECF) is ___ of body water.
A
- TBW: 60%
- ICF: 2/3
- ECF: 1/3
3
Q
- Total body water for infants is ___% of total body weight.
- Total body water for elderly is ___% of total body weight.
A
- 80%
- 45%
4
Q
Does a lean or an obese individual have a higher percentage of total body water?
A
Lean = 60%
Obese = 30%
5
Q
TIE : 60/40/20
A
- Total body fluid = 60% total body weight
- Intracellular = 40% of total body weight
- Extracellular = 20% of total body weight
6
Q
Definition:
- Total solute concentration in a fluid compartment
- What 3 solutes determine the calculated value of the ECF?
- Which solute is most important?
A
Osmolality
- Sodium (most important)
- Glucose
- Urea
7
Q
- Normal range for Osmolality is 280-295mOsm/kg
- Symptoms occur if >____ mmOsm/kg
A
>320
8
Q
What are 4 other “osmotically active” substances that aren’t included in the calculated osmolality?
A
- Mannitol (& other proteins)
- Ethanol
- Methanol
- Ethylene glycol (antifreeze)
9
Q
- A normal osmolal gap is
- A high osmolal gap is >___
A
- 10
- 10
10
Q
Definition:
- the ability of the combined effect of all of the solutes to generate an osmotic driving force that causes water movement from one compartment to another
A
Tonicity
11
Q
- To increase ECF tonicity, a solute must be confined to the _____ (unable to cross from ECF to ICF).
- ____ easily crosses cell membranes and therefore distributes evenly throughout total body water (so it contributes to ____, but NOT ____)
A
- ECF compartment
- Urea (contributes to osmolality, but NOT tonicity)
12
Q
- The reason why we care about tonicity is because it affects ____
- Decreased ___, leads to decreased tonicity of ECF, which causes a shift of water from ECF to ICF, which leads to _________.
A
- the size of cells
- Na / cells swelling w/ extra water (including brain cells)
13
Q
- The total amount of ___ in the ECF is the major determinant of the size of ECFV (extracellular fluid volume)
A
Na
14
Q
- Increased Na & increased ECFV
A
Hypervolemia
15
Q
- Decreased Na & Decreased ECFV
A
Hypovolemia
16
Q
Serum ___ is the principle cation in the ___ where 90-95% of total body __ is located.
A
Na / sodium
17
Q
Serum ___ (lab value) primarily refers to the amount of water relative to __ in the ECF.
(NOT the total body __ amount)
A
Na
18
Q
- Abnormal serum Na is a sign of ______.
- If Na is high, water is ___. (relative)
- If Na is low, water is ____. (relative)
A
- A disorder of water regulation
- too little
- too much
19
Q
With any sodium disorder, it is REALLY important to determine _____.
A
the patient’s volume status
