Acid/Base/Fluids/Electrolytes Flashcards
What is pH?
pH is the negative logarithm to the base 10 of hydrogen ions in solution and is a measure of the acidity of that solution.
What is normal physiological pH?
7.35-7.45 - H+ conc of 34-46nmols/l
Define ‘Acid’ and ‘base’.
An acid is a proton donor
A base is a proton acceptor.
What is a buffer?
A buffer is a weak acid and it’s conjugate base in solution that resists a change in pH of that solution.
What is the pKA?
The pKA is the pH at which 50% of the solution is ionised.
How does the body maintain constant pH?
- buffering
- compensation
- correction
Can you name buffering systems within the body?
Extracellular
- Bicarbonate
- Hb/plasma proteins
- phosphate
Intracellular 1. phosphate 2. ammonia 3. calcium 4, protein
What is the anion gap?
The anion gap is the difference between the concentrations between the measured anions and cations within the plasma.
(Na+ + K+) - (Cl- + HCO3-)
Usually 8-16mmol.l - accounts for unmeasured anions in plasma.
High anion gap.
lactate, ketoacids, exogenous acids, ethanol.
What causes a normal anion gap acidosis?
Bicarb loss - GI loss
Hyperchloraemic acidosis
Renal Tubular Acidosis
What is the base excess?
The base excess is a measure of how much acid or base needs to be added to a L of blood to return it to a normal pH when the CO2 is normal and at physiological temperature.