Acid-Base Balance II Flashcards
What is compensation?
the restoration of pH regardless of what happens to HCO3 or PCO2
What is correction?
restoration of pH and HCO3 and PCO2 to normal
What are the types of disturbances to A-B balance?
respiratory origin
non-respiratory origin
What are the blood buffers?
HCO3 and Hb
What are the ECF buffers?
HCO3
What has to rectify store depletion?
kidney
What can be analysed by blood gas?
CO2 and pH
What is plotted on the Davenport diagram?
HCO3 - y axis
Plasma pH = x axis
What is respiratory acidosis?
retention of CO2 by body
What can cause respiratory acidosis?
chronic bronchitis
chronic emphysema
airway restriction
chest injuries
What indicates uncompensated respiratory acidosis?
pH less than 7.35 due to increase H ion and PCO2 > 45mmHg
How is respiratory acidosis compensated for?
kidney increases H secretion and HCO3 reabsorption, generates titratable acids and NH4
How is respiratory acidoses corrected?
lowering of PCO2 by restoration of normal ventilation
What is respiratory alkalosis?
excessive removal of CO2 by body
What can cause resp. alkalosis?
low inspired PO2 at altitude causes ventilation
hyperventilation - fever and brainstem damage
hysterical over breathing
What indicates uncompensated respiratory alkalosis?
pH >7.45 and pCO2 less than 35mmHg
How is resp. alkalosis compensated for?
reduced H secretion
HCO3 is excreted
no new HCO3 is formed
How is resp. alkalosis corrected?
restoration of normal ventilation
What is metabolic acidosis?
excess H from any source other than CO2
What can cause metabolic acidosis?
ingestion of acids or acid producing food stuff
excessive production of H
excessive loss of base
What happens during metabolic acidosis?
HCO3 is depleted as a result of buffering of H or loss from body
What indicates uncompensated metabolic acidosis?
pH less than 7.35 and low HCO3
How does the respiratory system compensate for metabolic acidosis?
decrease in pH stimulates peripheral chemoreceptors
increase ventilation so more CO2 removed
H is lowered and HCO3 is also lowered
How is metabolic acidosis corrected?
lower filtered HCO3 and reabsorb it
H secretion continues and produces TA and NH4 to make new HCO3
acid load is excreted and HCO3 restored
ventilation is normalised
Why is respiratory compensation essential?
acid load cannot be excreted immediately
What is metabolic alkalosis?
excessive loss of H from the body
What can cause metabolic alkalosis?
loss of HCl from stomach - vomiting
ingestion of alkali or alkali producing foods
aldosterone hyper-secretion
What indicates uncompensated metabolic alkalosis?
pH > 7.45 and high HCO3
How does the respiratory system compensate for metabolic alkalosis?
decreased ventilation by peripheral chemoreceptors
How is metabolic alkalosis corrected for?
filtered HCO3 is not absorbed
no TA or NH4 is generated
HCO3 is excreted
HCO3 falls back to normal
