Do you use acetazolamide to aid diuresis in patients with acute on chronic respiratory acidosis with significantly elevated serum bicarbonate levels?

Yes, acetazolamide can be used in aiding diuresis in patients with chronic respiratory acidosis where the metabolic compensation results in an alkalemic pH which then sets up a vicious cycle of increasing CO2 as a compensation for the metabolic alkalosis. Use of acetazolamide results in a metabolic acidosis, leading to a drop in pH and PCO2. It stops working when the pH is <7.40.

The real question is do you use acetazolamide when there is a simultaneous primary metabolic alkalosis with a respiratory acidosis so that the pH is not low enough to give you a respiratory drive. It is usually from diuretics that create the metabolic alkalosis so using acetazolamide may reverse the metabolic alkalosis part. I do not find it to be a very strong diuretic, and you have to make sure you are not dealing with Cl deficiency that may maintain the met alk, but yes it is worth a try.

I do on occasion, the problem is that acetazolamide is actually a pretty weak diuretic when you are using it for primary metabolic alkalosis (even if on top of resp acidosis) which by definition has to have a strong maintenance mechanism to stay elevated, and then the mechanisms behind the maintenance are hard to overcome with a weak proximal diuretic.

If you give it in a pt with a normal GFR it works well (glaucoma, Mountain sickness) but as nephrologists, we are asking a lot from it when the rest of the nephron is all revved up to reabsorb Na, the times we consider using it.

The recent literature for using it in CHF however has changed my opinion a bit. But then I am not using it alone and it seems to work well in conjunction with a loo...