03 - fluids and acid-base metabolism

Question 1

(dehydration)

1. isotonic dehydration = ?

occurs when?

2. hypertonic dehydration = ?

most common w/ what?

3. hypotonic dehydration = ?

results in what?

Answer 1

1. equal loss of water and solute (NaCl conc not affected)

some cases of diarrhea and renal dz

2. more water than solute lost

diabetes insipidus

3. more solute than water lost (most common type, solute loss induces a 2° loss of water)

contraction of ECF

Question 2

know this

Question 3

(alkalosis and acidosis)

1. metabolic disorders - characterized by changes in HCO3

compensation is via what?

2. resp disorders - changes in P CO2

compensation via what?

Answer 3

1. via rapid changes in ventilation to alter P CO2
2. urinary acidification (slower than ventilation)

Question 4

1. what is a simple acid-base disorder?
2. what is a compensated acid-base disorder?
3. combined acid-base disorder?

Answer 4

1. primary change - but no compensation
2. primary changes, evidence of compensatory change but pH rarely returns to normal
3. changes in same direction in both systems

Question 5

1. ^ PCo2 causes alkalosis or acidosis?

how will this be compensated?

Answer 5

1. acidosis

HCO3 will increase in compensation

Question 6

(anion gap)

1. objective of measuring this?
2. what is the formula?
3. if anion gap increases, what does this mean?

if it decreases?

Answer 6

1. to estimate changes in the unmeasured anions and cations without having to measure them
2. (Na + K) - (Cl + HCO3)
3. unmeasured anions have increased

unmeasured cations have increased

Question 7

(osmolality)

1. osmolality = conc of osmotically active particles in aqueous solution

osmolal gap ^ when there is an ^ in any osmotically active particles that aren’t in calculated equation

2. does an ^ in osmolal gap ^ or dec when anion gap is increased?
3. used commonly in cases of what?

Answer 7

2. increase
3. ethylene glycol tox (osmotically active particle)