Dear Dr. Roach: I was just diagnosed with sudden sensorineural hearing loss. They gave me a steroid injection into the ear and more steroids by mouth, but they say it’s up to me whether I want to try hyperbaric oxygen.

Do you have any opinion on it? How does breathing pure oxygen at 2 atmospheres help anything? Is there some underlying theory to explain why people do this? It seems to me all this accomplishes is that it raises my blood oxygen level from 97% to 100%. How can this help anything?

— D.J.L.

Answer: Sudden sensorineural hearing loss is an uncommon condition. It can often be misdiagnosed, and since some people get better on their own, it is sometimes never diagnosed at all.

I suspect there isn’t one single cause in all cases as several causes have been proposed, including infections, especially viral; medications and recreational drugs; brain tumors; autoimmune diseases; head trauma; and associations with other diseases. However, most cases have no clear underlying cause.

In addition to a careful exam, hearing testing and an MRI of the brain is generally recommended. Early treatment with steroids (either by injection, orally or both) has been shown to enhance recovery.

In people with more severe hearing loss, hyperbaric oxygen has been shown to improve outcomes compared to steroids alone. It is thought that the high amount of oxygen delivered via the hyperbaric chamber may be able to deliver oxygen to areas of the cochlea that were damaged, but the mechanism of action isn’t completely clear.

The benefit of hyperbaric oxygen isn’t getting your red blood cells more oxygenated. You can’t do better than 100%, and 97% is very close to 100%. With hyperbaric oxygen, the fluid of the blood itself carries much more oxygen, which is dissolved in the plasma — not in the red blood cells. The oxygen in the fluid is 60 times higher with 3 atmospheres of oxygen compared to room air, which is enough to deliver oxygen to your tissues without red blood cells.

Carefully done, the risks of hyperbaric oxygen are small. The high pressure can cause pain and pressure in the ear and sinuses, which can be relieved by equalizing pressure through maneuvers that open the Eustachian tube (such as yawning or swallowing).

While I understand why physicians want to get your opinion on your treatment, it doesn’t sound like they gave you enough information to make an informed choice. In my opinion, they should have gone over the risks and benefits, then given you a clear recommendation.

Dear Dr. Roach: In a recent column, you stated that the body works to keep blood pH levels steady. My urologist has recommended that I drink baking soda in water to alkalinize my urine. Is it true that urine pH levels can be changed even though blood pH levels cannot?

— C.T.

Answer: This is true. Your urologist is taking advantage of the fact that your kidneys will excrete the bicarbonate ion into your urine very quickly after you take it in by mouth. (Baking soda is sodium bicarbonate. We sometimes use potassium bicarbonate for this purpose, too.) Your blood pH will stay normal, but the urine pH will go up into the alkaline range.

Kidney stone specialists use this to reduce formation of uric acid stones. Potassium citrate also has the same effect on urine pH levels. With a higher urine pH (even just to 6.5 or 7), uric acid cannot form stones. Long-term treatment with urinary alkalinization dramatically decreases stone formation.

Contact Dr. Roach at ToYourGoodHealth@med.cornell.edu.