Dissociation of renal and respiratory effects of acetazolamide in the critically ill.

The effects of acetazolamide on renal and erythrocyte carbonic anhydrase were studied in 12 critically ill patients. In the first part of the investigation (n = 6) we examined the renal effects of increasing doses of acetazolamide. The maximal renal excretion of water and bicarbonate was achieved with acetazolamide 2.5-5 mg kg-1 i.v. In the second part (n = 6), the associated respiratory effects of the effective renal dose of acetazolamide 5 mg kg-1 were evaluated. We found a statistically significant 4% decrease in pulmonary carbon dioxide excretion in the 10-min sampling period immediately following the administration of acetazolamide, but thereafter carbon dioxide elimination proceeded at a normal rate. The observed carbon dioxide retention is clinically unimportant, and we recommend acetazolamide as an effective means of eliminating surplus water and bicarbonate in the critically ill.