Hyperbaric oxygen therapy may relieve IC symptoms

August 15, 2006

Atlanta-Just breathe. Could that be the key to easing interstitial cystitis pain?

Atlanta-Just breathe. Could that be the key to easing interstitial cystitis pain?

It may well be. But no, it's not yoga. It's hyperbaric oxygen (HBO) therapy, the therapy used to treat divers' "bends," radiation cystitis, and poorly healing wounds, among other conditions.

In Dr. van Ophoven's study, patients were randomly assigned to 30 treatment sessions of 90 minutes each in a multiplace HBO chamber pressurized either with 100% O2 at 2.4 ata (12 patients) or to normal air at 1.3 ata (seven patients). Patients and investigators were strictly blinded as to which therapy was being given. Only the operator of the chamber knew which air was being given. Patients can't tell the difference, Dr. van Ophoven pointed out, because although the inner ear is sensitive to increased pressure, it's not sensitive to the degree of pressure, so even the patients breathing normal air felt that it was pressurized.

The primary outcome measure was improvement in symptoms, reported in a Global Response Assessment questionnaire that gauges change on a 7-point scale ranging from markedly worse to markedly better. Patients reporting any improvement were considered responders.

Secondary outcome measures included relief from pain and urgency, based on patient-reported scores on a visual analog scale, functional bladder capacity, and 24-hour frequency. In addition, patients' scores on the O'Leary-Sant Symptom and Problem Index and their ratings of overall satisfaction were considered.

Efficacy of treatment was evaluated at the end of treatment and at follow-up appointments at 1, 3, 5, 9, and 12 months post-treatment. The code was broken at 3 months following evaluation.

'Surprising' results

Dr. van Ophoven conceded to Urology Times that he was "pretty surprised" at the effectiveness of the therapy. In those patients who responded to HBO therapy, pain and urgency dropped by one-third to one-half as reported on the visual analog scale.

Patient responsiveness seemed to follow an all-or-nothing rule, Dr. van Ophoven said. Those who responded did so early and had a high probability of ongoing improvement. Those who did not improve by the end of therapy also did not improve later.

Among the 14 patients who received 100% O2, two patients dropped out of the study, four did not respond to therapy, and eight responded to therapy (p?.001). Of the eight responders, five reported slight improvement, two reported moderate improvement, and one reported marked improvement at 3 months. Twelve months after therapy, five patients (42%) reported sustained improvement: Two were slightly improved, two were moderately improved, and one was markedly improved.