A randomized controlled study comparing carbon dioxide versus normal saline as distension media in diagnostic office hysteroscopy: is the distension with carbon dioxide a problem?

To compare two distension media, carbon dioxide (CO2) and saline, with regards to patient discomfort and the adequacy of the panoramic view in diagnostic hysteroscopy by the vaginoscopic approach.Randomized prospective study.Tertiary referral centers for gynecologic care.264 patients randomly allocated to two groups: CO2 (132 women) and normal saline (132 women).Office hysteroscopy performed with a forward-oblique 30° telescope (total diameter 5.1 mm) and CO2 as the distension medium or with a forward-oblique 30° telescope (final diameter 5.1mm) and saline solution as the distension medium.Global operative time, pain experienced by patients using a visual analogue scale (VAS), severity of the pain (VAS), incidence of collateral effects (shoulder-tip pain, nausea, or dizziness), degree of difficulty, and view (VAS).Pelvic discomfort was comparable between groups, without statistically significant differences in intensity or degree of difficulty. However, the visual quality was statistically significantly higher when hysteroscopy was performed with CO2 as the distension medium.No relevant difference in pain or technical difficulty was found between the two distension media, but CO2 was associated with better quality visualization.