14 - Fluid And Electrolyte Flashcards
Gold standard for measuring urine concentration of electrolyte?
24 hr urine collection
- thought the fractional excretion from spot urine is more convenient
What does fractional excretion help determine? (Results)
The kidney’s response to a specific electrolyte
- Low fractional excretion - renal absorption
- High fractional excretion - renal wasting
Disorders of sodium concentration are a result of?
Water balance
Disorders of ECF volume are a result of?
Disturbances in sodium balance
What does serum sodium indicate?
What does it not reflect?
Indicates - relative amounts of sodium and water
Does not reflect ECF volume status
Hyponatremia is (level)?
Serum sodium <135 mEq/L
Clinical findings of hyponatremia?
Nausea Malaise HA Lethargy Disorientation
Respiratory arrest
Seizure
Coma
Brainstem herniation
hyponatrema needs to be carefully corrected to avoid?
Central pontine myelinolysis
Hyponatremic pts serum osmolality?
Can be
low - isotonic hyponatremia
normal- hypotonic hyponatremia
high - hypertonic hyponatremia
Chart on slid 11 if you want
Hypernatremia is (level)?
Serum sodium >145mEq/L
Hypernatremia always has?
Hyperosmolality
But may still be hypo, eu, or hypervolemic
Urine osmolality is used to measure?
The kidneys ability to conserve water
Distinguish between renal and non-renal losses
Tx for hypernatremia?
Fluid replacement
Disorders of sodium balance include?
Hypervolemia - volume overload
- abnormal na retention
Hypovolemia - decreased ECF volume
- Na excretion > Na input
How is a pts acid-base status measured?
Combination of
- arterial pH
- PCO2
- Plasma bicarbonate (HCO3)
Chart of results on slide 16
How do kidneys regulate acid-base balance?
Reabsorbing HCO3
Creating new HCO3
Excretion of H
Acid base mnemonic?
ROME
R - respiratory O - opposite (respiratory) —H pH; L PCO2 = alkalosis —L pH; H PCO2 = acidosis M - metabolic E - equal (metabolic) —H pH; H HCO3 = alkalosis —L pH; L HCO3 - acidosis
Different acid base d/o s/s?
Slid 18 there are pics
Analysis of acid-base status steps?
Step 1 - determine metabolic vs respiratory
Step 2 - calculate range of compensatory respobses
- determines presence of mixed d/o
Step 3 - calculate anion gap
Step 4 - calculated corrected HCO3
Step 5 - look for clinical signs
Acid base d/o results down and dirty?
(Metabolic is equal) Metabolic acidosis (all low) - L pH; L HCO3; L CO2 Metabolic alkalosis - H pH; H HCO3; H CO2
(Respiratory is opposite) Respiratory acidosis - L pH; H HCO3; H CO2 Respiratory alkalosis - H pH; L HCO3; L CO2
Metabolic acidosis is classified as?
Normal
Or
Increased anion gap
Anion gap is slide 21
RTA (renal tubular acidosis) must have?
Normal anion gap
Normal GFR
NOT CAUSED by diarrhea
RTA is?
Impaired renal bicarb absorption or hydrogen excretion
Not caused by diarrhea
classic distal RTA type I?
Hyperchloremic acidosis
- usually hypokalemic
Deficiency in H+ secretion at DCT
Urine will be alkaline (>5.5)
