Acetazolamide-mediated decrease in strong ion difference accounts for the correction of metabolic alkalosis in...

Area of Science:

• Nephrology
• Critical Care Medicine
• Acid-Base Physiology

Background:

• Metabolic alkalosis is a frequent acid-base disorder in intensive care units.
• Acetazolamide, a carbonic anhydrase inhibitor, is used for specific metabolic alkalosis cases.
• The precise mechanism of acetazolamide's action in metabolic alkalosis requires clarification.

Purpose of the Study:

• To investigate the mechanism of acetazolamide's action in critically ill patients with metabolic alkalosis.
• To utilize the quantitative Stewart approach to analyze acid-base balance.
• To elucidate how acetazolamide corrects serum pH in this patient population.

Main Methods:

• A cohort of 15 intensive care unit patients with metabolic alkalosis received a single intravenous dose of acetazolamide.
• Serum and urine electrolytes, pH, and other relevant parameters were measured serially over 72 hours.
• Calculations included strong ion difference (SID), strong ion gap, and sodium-chloride effect.

Main Results:

• Acetazolamide administration led to effective correction of serum pH, sustained for 72 hours.
• A significant decrease in serum SID was observed, primarily driven by an increase in serum chloride levels.
• Increased urinary excretion of sodium without a corresponding increase in chloride explained the reduction in serum SID.

Conclusions:

• A single dose of acetazolamide effectively corrects metabolic alkalosis in critically ill patients.
• The primary mechanism involves a decrease in serum SID due to enhanced renal sodium excretion over chloride.
• This leads to an increase in serum chloride, thereby correcting the alkalosis.