Acid base abnormalities Flashcards
diff betwen acidosis and acidemia
osis is the processes that tend to change ph in a given direction
emia is the resultant pH of the blood
acedemia pH
<7.4
alkalemia pH
> 7.4
sites of acid base regulation
chemical buffers
lung
kidney
metabolic acidosis
serum bicarbonate <24meq/L
metabolic alkalosis
serum bicarb >24meq/L
normal sodium bicarb
18-24 meq/L
respiratory acidosis
pco2 >40mmhg
respiratory alkalosis
pco2 <40mmhg
normal pCO2
35-40mmghg
major chemical buffer
pH dependent on relative ratio between carbon dioxide(acid) and bicarbonate (base)
if altered get an acid base abnormality
respiratory regulation of co2 elimination
medullary chemoreceptors in the respiratory center are activated by cerebral arterial CO2
lungs compensate for metabolic disturbances
increasing the rate and depth of respiration increases ….
quantity of CO2 to be eliminated by lungs
renal regulation of H/HCO3
kidneys reabsorb filtered bicarbonate and eliminate H
takes much longer - in resp acidosis
in presence of resp acidosis the kidneys..
excrete hydrogen ions and conserve bicarbonate ions
in presence of resp and metabolic alkalosis kidneys..
retain H and excrete bicarb
resp alkalosis compensation
every 10mmhg decrease in co2, hco3 decrease by 2mmole
resp acidosis compensation
every 10mmhg increase in pco2, hco3 increase by 1mmole
metabolic alkalosis compensation
every mmole increase in hco3, pco2 increase 0.7mmhg
metabolic acidosis compensation
every decrease in hco3, pco2 decrease by 1mmhg
in acid base disorder if the expected compensatory response hasnt occurred what does that indicate
mixed acid base disturbance
what is an anion gap
difference in cations and anions
AG = unmeasured anions - unmeasured cations
…… i think this is backwards…..
why is K not included in anion gap calculation
largely an intracellular cation that rarely alters the gap
anion gap formula
AG = (Na) - (Cl + HCO3)
what is the normal anion gap
12 +/- 4 mEq/L
what does a high anion gap mean
increased unmeasured anions or decreased unmeasured cations
what is high anion gap metabolic acidosis
generation of acid that titrates the bicarbonate with an unmeasured anion
chloride concentraion remains normal (normochloremic acidosis)
what is normal anion gap metabolic acidosis
processes that cause bicarbonate loss and chloride retention
chloride concentraion higher (hyperchloremic acidosis)
causes of high anion gap metabolic acidosis
renal failure
lactic acidosis
ketoacidosis
drugs and toxins
causes of normal anion gap metabolic acidosis
acetazolamide acidifying agents cholestyramine GI bicarbonate loss (diarrhea) chloride retention (renal acidosis)