ACID BASE DISORDERS Flashcards
What is the bodily PH ?
7.4
What are acid base disorders ?
Metabolic acidosis
Respiratory acidosis
Metabolic alkalosis
Metabolic acidosis
What is acid base physiology associated with?
What is the rel between H+ and ph?
Hydrogen ion balance
ph= -log(H+)
inverse and non linear
What occurs when there is a change in PH?
When there is a change of 0.3 units of PH, a change by a factor of 2 occurs in H+
What is the net acid production ?
100mmol/day
Types of buffering
Good buffering- carbonic anhydrase
Bad buffering-bone, Hgb and plasma proteins
What occurs when the PH is 6.8
grand mal seizure or ischaemic bowl disease
Describe the rel of Ph to bicarbonate and Co2
Henderson Hesselback’s equation PH = bicarb/c02
Features of metabolic acidosis
increase in fixed acids (lactate, acetoacetate and beta hydroxybuturate) in blood
Must occur in same direction
so decrease in plasma
What causes a decrease in plasma bicarbonate?
gain in strong acid via endogenous sources; ketoacids
loss of base via kidneys/diarrhea
What can metabolic acidosis be classified into?
increased anion gap
normal anion gap
Define anion gap and normal AG ?
Cations (sodium plus potassium) minus anions (bicarbonate plus chloride). If
hydrogen ions accumulate, the hydrogen ion is not accounted for on the cation side, but the
decrease in bicarbonate buffer compensation would appear as a bicarb deficit, and the anion
gap would increase
normal AG - 8-12. This is used to diagnose metabolic acidosis
What accounts for a high anion gap?
P04, IgA, albumin, lactate
high Anion gap accounts for above (these are the unmeasured anion and cations)
normal anion gap if Cl and HCO3 are the only anions that are elevated
Causes of NAGMA
Cl intoxification
- Cl gas intoxification
- Hcl intoxification
- early renal failure
- dilutional acidosis
Gi loss of HCo3
- diarrhea
- surgical drains
- fistulas
- uterosigmoidostomy
- obstructed uteroileostomy
- cholestyramine
Renal loss of HCO3
-RTA ; proximal distal , hypoaldosteronism
What are the differiental diagnosis of raised anion gap metabolic acidosis?
- lactic acidosis
- ketoacidosis
- renal failure
- poisonings