Acid-base Flashcards
What is the Henderson-Hesselbach equation?
pH = pKa + Log(HCO3- / H2CO3)
What is a buffer?
A solution consisting of a weak acid and its conjugate base which resists change in pH when stronger acid/base is added
What does an effective buffer system depend on?
- Amount of buffer
-pKa - pH of carrying solution
- Whether it functions as an open/closed system
How is CO2 carried in the blood?
- Dissolved in plasma
- Bicarbonate
- Carbamino compounds (in RBC)
What is the Haldane effect?
Property of Hb
Following Bohr effect Hb left in deoxygenated state
Facilitates binding of H+
What is the Bohr effect?
Carbon dioxide and hydrogen ions affect haemoglobin’s oxygen affinity.
What is the anion gap?
A measure to help identify the cause of metabolic acidosis either
- organic acid (raised gap)
- Loss of HCO3 (normal gap)
What is the anion gap equation?
AG = (Na + K) - (Cl + HCO3)
What are the causes of high anion gap?
- Lactate
- Toxins
- Ketones
- Renal (reduced acid excretion)
What are the causes of normal anion gap?
- Addisons
- Cl- excess
- Diuretics
- Bicarb loss (RTA/GI)
What are Stewart’s concepts?
- Electro-neurtality
- Dissociation
- Mass conservation
