What causes the contraction of the ECF volume?
When there is a deficit of NaCl without a simultaneous loss of NaHCO 3 , the content of HCO 3 − in the ECF compartment does not change, but the [HCO 3 − ] rises because the denominator of the content of HCO 3 − /ECF volume (see equation in Question 4) is diminished.
This contraction type of metabolic alkalosis is particularly important when there is a large decrease in the ECF volume (e.g., in patients with massive diarrhea or when diuretics are given to patients with congestive heart failure).
