Arterial Blood Gases & Acid Base Regulation Flashcards
What should be in equilibrium with pCO2 (theoretical)?
Bicarbonate
What is FMetHb?
ferritin NOT ferrous in the haem- molecule that is unable to bind O2
What does acidosis need to correct?
alkalosis
What does hyperventilation result in?
increased CO2 clearance
What are the 4 key aspects found from an ABG?
- what is the type of imbalance?
- what is the aetiology of imbalance?
- any homeostatic compensation?
- oxygenation?
How to assess compensation?
- both values should change
- only one indicates it is UNcompensated
- changes in pH suggest partial compensation
What is base excess?
the difference between the actual bicarbonate and the expected bicarbonate
How do you calculate pH?
-log10[H+]
How do you calculate [H+]?
10^-pH
What is an acid?
any molecule that has a loosely bound H+ ion that it can donate
What is an base?
an anionic (-ive) molecule that can reversibly bind protons
What proportion of acid is respiratory (CO2) or metabolic (lactic, HCl…)?
about 95:5
What does alkalosis need to correct?
acidosis
What can cause a rapid compensation?
changes in ventilation change CO2 ventilation, altering pH
What can cause a slow compensation?
Changes in HCO3- and H+ retention/secretion in the kidneys, lead to changes in pH
How long does slow consumption take?
up to days
What is acidosis/alkalosis?
conditions that cause a change in pH
What is alkalaemia/acidaemia?
whether pH is above/below 7.35-7.45.
What are the different types of imbalance?
- acidosis
- alkalosis
- normal