ABGs Flashcards
bodys physiological processes work best at what pH?
7.35-7.45
most important extracellular buffer system?
CO2 + H2O <> HCO3 H+ system
HCO3 is excreted or reabsorbed where?
kidney
concentration of CO2 or HCO3 changes quicker?
CO2
what can the body do to correct a pH balance?
rapidly gain/lose CO2
slowly gain/lose HCO3
(can alter pH in right direction but not return to normal)
(cannot overcompensate)
what happens in metabolic acidosis?
excess of H+ produced by the body due to disease (lactic acidosis/renal failure/sepsis etc)
body tries to compensate and balance equation by getting rid of CO2
features of metabolic acidosis?
reduced pH
tachypnoea with redcued CO2
reduced HCO3 as it is used up by the pH
what happens in resp acidosis?
accumulation of CO2 due to disease of lungs or problem with resp mechanics
body counteracts this by accumulating HCO3 via reabsorbing it in the kidneys (slow process)
features of resp acidosis?
acute = reduced pH
increase in CO2
little - no change in HCO3
chronic = increased HCO3 as kidneys have had time to reabsorb it
what happens in metabolic acidosis?
usually due to a net loss of acid from body (e.g vomiting) leaving excess alkali
body counteracts this by holding on to CO2 via hypoventilation
features of metabolic alkalosis?
elevated pH
marginal increase in CO2 (hypoventilation not very effective)
what happens in resp alkalosis?
due to relative lack of acid as too much CO2 is lost due to hyperventilation (pain, anxiety, sepsis etc)
appropriate response would be to lose HCO3 but this is slow and the hyperventilation is usually short lived so HCO3 loss is rarely seen
features of resp alkalosis?
elevated pH
hyperventilation
low CO2
little change in HCO3
