6.5. Simple Acid/Base Disorders - Metabolic Alkalosis

Question 1

What is metabolic alkalosis?

Answer 1

Alkalosis of metabolic origin

Question 2

What is the mechanism of metabolic alkalosis?

Answer 2

An increase in blood bicarbonate concentration

Question 3

What will happen to the PCO2 to protect the pH?

Answer 3

It will increase

Question 4

What causes metabolic alkalosis?

Answer 4

1. An increase in H+ ion loss due to vomiting (due to the loss of the Gastric secretions)
2. An increase in renal H+ion loss due to aldosterone excess
3. Excess administration of bicarbonate - unlikely unless renal function is impaired
4. Massive blood transfusions

Question 5

Why can massive blood transfusions cause metabolic alkalosis?

Answer 5

As bank blood contains citrate to prevent coagulation, and citrate is later converted into bicarbonate

Question 6

What happens in metabolic alkalosis?

Answer 6

The greatly increased filtered load of bicarbonate exceeds the level of H+ ion secretion to reabsorb it so the excess is lost in the urine

Question 7

What does respiratory compensation allow for?

Answer 7

This delays the renal correction but protects the pH