B4.038 - Interpreting Arterial Blood Gas Prework 2 Flashcards
why do we care about acid base balance
automatic differential early sign of illness prevent end organ damage
what is a mixed acid base disorder
more than one disorder present, pH may be normal or abnormal, if abnormal trend toward the dominant disorder
what is an example of respiratory acidosis
Opioid overdose, decreased ventilation
what are acid base disorders accompanied by
expected compensation renal and respiratory
what will compensation do
just trend in right direction will NOT return pH to normal
what is metabolic acidosis
primary disturbance of blood HCO3 concentration where it is decreased
what are two types of metabolic acidosis
anion gap non anion gap
what is metabolic alkalosis
higher HCO3 concentration than normal usually due to retention
what is the normal compensatory mechanism for metabolic acid base imbalance
respiration changes in ventilation mediated by chemoreceptors in carotid body and lower brainstem
what are metabolic alkalosis causes
nasogastric suction, vomiting
diuretic therapy
Hyperaldosteronism - Addison’s disease
cushing syndrome
exogenous steroids
licorice overdose
alkali ingestion
what is anion gap acidosis
HCO3- used as buffer for acid
differentiate between anion gap metabolic acidosis and non anion gap metabolic acidosis
anion gap is when HCO3- used up as a buffer for acid
non anion gap is when its lost through urine or bowel
anion gap metabolic acidosis causes
methanol
uremia
DKA
paraldehyde
INH/Iron
Lactic acidosis - sepsis
ethylene glycol
salicylates/starvation
non gap metabolic acidosis
hyperailmentation
Diuretics
renal tubular acidosis
diarrhea
ureteroenteric fistula
pancreaticoduodenal fistula
why is it important to differentiate between anion gap metabolic acidosis and non anion gap metabolic aidosis
the treatments are very different
how do you treat non gap MA?
replace bicarb
how do you treat anion gap MA
treat the underlyind disorder
you DONT give bicarb unless its severe
what is winters formula
predicts the expected pCO2 for any given HCO3- level
expected pCO2 = (1.5 x [HCOD3-]) + 8 +/- 2
used in pts with metabolic acidosis to see if their respiratory compensation is enough
normal compensation for repiratory disoders
metabolic in kidney
respiratory acidosis is caused by
CO2 retention
decreased alveolar ventilation
disorders causing respiratory acidosis
CNS depression/sedatives
neuromuscular disorder
thoracic cage limitations
Acute obstruction
chronic obstruction
ventilator malfunction
disorders causing respiratory alkalosis
anxiety
CNS disorders
drugs- salicylates, analeptics
fever, sepsis (usually not, usually lactic acidosis)
pregnancy (FRC decreases – harder to maintain high TV)
liver insufficiency
hyperthyroidism
