mccarthy- acid/base Flashcards
what is “contraction alkalosis”?
ECF vol decreases –> RAAS –> angiotensin II stimulates Na+/H+ exchange in proximal tubule (excrete more H+) = HCO3 increase reabs into serum.
what causes “contraction alkalosis”?
taking loops or TZDs
or vomitting or diarrhea
txt for “contration alkalosis”?
restore ECF vol. w/ infusion of isotonic NaCl
what is the aldosterone effect?
acts on late distal tubule + collecting ducts
- activates Na/H/K pumps
- Na+ reabsorption
- H+ and K+ excretion
what are two stimulus for aldosterone production?
- activation of RAAS b/c of decreased kidney perfusion
- hyperkalemia
what does prednisone do?
same thing that aldosterone does
what disorder is this?
- vol. expansion w/ HTN
- hypokalemia
- metabolic alkalosis
hyperaldosteronism
what disorder is this?
- vol. depletion w/ orthostatic hypotension
- hyperkalemia
- metabolic acidosis
hypoaldosteronism
normal pCO2 value, normal pH value
pCO2: 35-45
pH: 7.35-7.45
what is acid-base balance?
maintaining normal H+ conc. in body fluid by buffers in ECF and ICF
what two types of respiratory mechanisms regulate acid/base
alveolar hyperventilation (blow off CO2) - pCO2 will be <35 alveolar hyporventilation (retain CO2) - pCO2 will be >45
what two renal mechanisms regulate acid/base
reabsorb HCO3- and secrete H+
which compensatory mechanism is fast vs slow?
fast: respiratory- min-hrs
slow: renal- hrs- days
what is the pH of alkalotic blood? what does the body try to do?
pH>7.45
- body tries to correct by hypoventilation (to increase CO2)
what is the pH of acidotic blood? what does the body try to do?
pH <7.35
- body tries to correct by hyperventilation (to decrease CO2)
what are the two forms of acids produced?
- volatile: end product of aerobic metabolism: CO2
- non-volatile/fixed: end product of protein and phospholipid catabolism: sulfuric acid + phosphoric acid
what does “non-volatile” mean?
not expelled by the lungs - must be buffered in body fluid THEN excreted by kidneys
(take H+from alpha intercalated cells so they can be excreted in urine) “titratable acids”
what is the weak acid formed by CO2 metabolism?
carbonic acid H2CO3
what is the significane of pK
it is esentially the pH when the acid/base equation is at equilibrium (50% CO2 and 50% HCO3-)
what is the relationships of pH with HCO3 and CO2?
pH = HCO3/CO2
direct relation with HCO3
indirect relation with CO2
in what order are lab chemistries given?
Na/K/Cl/HCO3-
what is CO2 CONTENT?
HCO3- in serum
how to convert pCO2 to dissolved CO2?
pCO2 * 0.03 = dissolved CO2
how can hyperK cause acidosis? ( weeds)
Hyperkalemia inhibits NH3 synthesis and reduces the ability to excrete H+ as NH4+.
“NH3 is like an acid carrier, and if you dont have this carrier then you cant carry it out- so you have acidosis.”
how can hypoK cause alkalosis? (weeds)
Hypokalemia stimulates NH3 synthesis and increases the ability to excrete H+ as NH4+.
what can cause hypoventilation?
COPD, benzos/opiods, CHF, pneumonia (does both)
what can cause hyperventilation?
panic attack, septic, high altitude, PE, pneumonia (does both)
normal value Na
135-145
normal K
3.5 -5
normal Cl
98-106
what does Cl- compete with for abs in the kidney?
HCO3-
what causes high anion gap?
DKA, lactic acidosis, chronic renal failure
what causes non-anion gap?
renal tubular acidosis, diarrhea (poop out HCO3- )
what is a high anion gap significance?
there is chronic metabolic acidosis and the acid is coming from something else (other than your natural body processes) - TOO MUCH ACID
what causes non anion gap
hyperChloremia (which competes with HCO3-, keeping anion gap the same)
