Arterial Blood Gasses Flashcards
at what pH do the body’s physiological processes work best?
7.35-7.45
what reaction creates the most important extracellular buffer system?
CO2 + H2O to HCO3 + H+
what is the waste produce of respiration in all body cells?
carbon dioxide
what controls the retention/excretion of carbon dioxide from the body?
the lungs
the concentration can be changed rapidly by breathing faster/slower
what pH does CO2 have?
acidic
what is HCO3?
bicarbonate
what pH does HCO3 have?
basic
what controls the retention/excretion of HCO3 from the body?
the kidneys
it is either excreted or absorbed
which can change faster, concentration of CO2 or HCO3?
CO2
what is compensation>
when the body attempts to correct a pH balance by losing/gaining CO2 or HCO3
when does metabolic acidosis occur?
when the body produces excess H+
name three things that can cause metabolic acidosis
lactic acidosis
renal failure
sepsis
how does the body attempt to cope with metabolic acidosis?
by getting rid of CO2
what would be seen on the ABG of someone with metabolic acidosis?
reduced pH
reduced CO2
reduced bicarbonate
when does respiratory acidosis occur?
when there is an accumulation of CO2 when there is a problem with the lungs
how does the body attempt to cope with respiratory acidosis?
resorbing bicarbonate from the kidneys
this is a slow process
what would be seen on the ABG of someone with ACUTE respiratory acidosis?
reduced pH
increased CO2
no change in bicarbonate
what would be different on the ABG of someone with CHRONIC respiratory acidosis compared to acute?
increased bicarbonate because the kidneys have had time to absorb it to counteract the low pH
when does metabolic alkalosis occur?
when there is a net loss of acid from the body, resulting in an alkali surplus
how does the body try to cope with metabolic alkalosis?
tries to hold on to acid by hypoventilating and retaining CO2
what is a common cause of metabolic alkalosis?
vomiting
what is seen on the ABG of someone with metabolic alkalosis?
elevated pH
small increase in CO2
what causes respiratory alkalosis?
lack of acid due to loss of CO2
caused by hyperventilation
how does the body attempt to cope with respiratory alkalosis?
loss of bicarbonate
this is slow and rarely seen as respiratory alkalosis is usually short lived
what is seen on the ABG of someone with respiratory alkalosis?
elevated pH
low CO2
little change in bicarbonate
what is PO2?
partial pressure of oxygen in arterial blood (aka PaO2)
what does high PaCO2 suggest?
respiratory acidosis
what does low PaCO2 suggest?
respiratory alkalosis
what is BE?
base excess
a measure of how much base has been added/removed to correct the pH
what does negative BE suggest?
metabolic acidosis
what does positive BE suggest?
metabolic alkalosis
