BMP highlights Flashcards
1) List the tests in a BMP (know these)
2) What is the test that’s freq. included?
1) Sodium, potassium, chloride, bicarb(onate), BUN, creatinine, glucose
2) Calcium
Doubling of serum creatinine suggests ___% reduction in GFR
50%
Urea formed in the ___________ as a metabolic byproduct; BUN is excreted by the ____________.
liver; kidneys
Normal range of HCO3: _________ mEq/L
(know this)
22-26
Urine concentration of an electrolyte is helpful when compared to what?
serum levels
1) What is the gold-standard test to assess electrolytes with urine?
2) What is the more convenient test?
1) 24-hour urine collection to monitor electrolyte excretion
2) Fractional excretion (FE) of an electrolyte
Fractional excretion (FEx):
1) Low fractional excretion indicates ________
2) High fractional excretion indicates ________
1) retention
2) excretion
Osmolality of all solutes (electrolytes and others) in plasma is what?
280-295 mmol/kg
1) What is the normal serum range for sodium?
2) What is the normal serum range for potassium?
3) Are magnesium and phosphorus on BMP?
1) 135 – 145 mEq/L
2) 3.5 – 5.0 mEq/L
3) No; ordered separately
Sodium:
1) Is the main __________ cation
2) And the main determinant of extracellular __________ (affects fluid shifts)
1) extracellular
2) osmolality
1) _____________ is the most common electrolyte abnormality.
2) Is serum osmolality normally low, normal, or increased?
1) Hyponatremia
2) Usually low (hypotonic), sometimes normal or increased
1) Define severe (critical) hyponatremia
2) What is the normal sodium reference range?
3) Define severe (critical) hypernatremia
1) <125
2) 135-145 mEq/L* (important)
3) >160
Hyponatremia is usually due to an ________________________ diluting serum Na+, rather than a deficiency in total body Na+. (cells swell)
excess of total body water
What is the serum osmolality in hypernatremia; low, normal, or high?
Always high (unlike hyponatremia, which can be variable)(cells shrink)
Clinical manifestations and treatment of hypo/hypernatremia depend on what 2 things?
1) How far Na+ is outside of the normal range (severity)
2) Acuity of onset*
Differentiate between acute and chronic forms of hypo/hypernatremia (i.e. how long is each?)
Acute <48 hrs vs. chronic ≥48 hrs
(same concept applies to electrolyte disorders in general)
Acute and severe symptoms of hypernatremia may be seen with with Na+ >_____
> 160
What should the initial labs for hyponatremia include?
1) Serum and urine electrolytes
2) Serum and urine osmolality
What are the 3 initial labs for hypernatremia?
1) Serum sodium
2) Urine volume flow rate (oliguric or nonoliguric)
3) Urine osmolality
Hyponatremia: Serum osmolality ________ most of the time; urine osmolality usually _________
low; high
What are the 2 categories of hyponatremia? List causes of each
1) Pseudohyponatremia (normal serum osmolality)
Severe hypertriglyceridemia or hypergammaglobulinemia throws off sodium reading
2) Hypertonic (hyperosmolar) hyponatremia
Hyperglycemia and (less common) mannitol infusion
To calculate “corrected” sodium in hyperglycemia, increase sodium by _____ for every 100mg/dL rise in plasma glucose above normal (100 mg/dL)
1.6
What is the most common hyponatremia? How can you break that down further?
Hypotonic (hypo-osmolar) hyponatremia
What measurement defines “dilute urine”?
Urine osm <100