Acid Base Balance Flashcards
Why is urine profoundly acidic
H+ is excreted through urine
How is H+ buffered
H + HCO3- = H2CO3 = CO2 + H2O
H + Hb = HHb
How is H2CO3 removed
Carbonic acid is remvoed as CO2 from the body
Acidosis and acidaemia vs alkalosis vs alkalaemia
Acidosis is a process causing acidaemia which is low blood pH. Alkalosis is a process causing alkalaemia which is high blood pH due to low H+
Respiratory component
CO2
Metabolic component
HCO3-
H+ proportionality to CO2 and HCO3-
H+ proportional to CO2/HCO3-
How is high H+ and high CO2 compensated
High H+, more CO2 produced and breath out by lungs
High CO2, more H+ secreted in urine via kidney
What can cause respiratory acidosis
Choking, bronchopneumonia, COPD
What can cause respiratory alkalosis
Hysterical overbreathing, mechanical over ventilation, raised intracranial pressure
What can cause metabolic acidosis
Impaired H+ secretion, increased H+ produced or ingestion, loss of HCO3-
What can cause metabolic alkalosis
Loss of H+ in vomit, alkali ingestion, hypokalaemia
When to consider mixed acid-base disorder
If CO2 and HCO3- change in opposite directions
Why can haematemesis cause metabolic acidosis
There is lack of perfusion of tissue due to blood loss. This means tissues have to metabolise fuel in the absence of oxygen resulting in production of lactate. This dissociates H+ releasing an acid load
Person with COPD and stabilised on treatment would have?
Respiratory acidosis but compensated (raised bicarbonate)
