Carbon dioxide in office diagnostic hysteroscopy: An open question. A multicenter randomized trial on 1982 procedures

to compare carbon dioxide and saline solution distension in diagnostic hysteroscopies with regards to patient discomfort and procedural time and in accordance with the instrument diameter (5 mm vs 3.5 mm). The secondary outcome was to evaluate the role of the patient age and the obstetrical history on perception of pain and procedural time.

This is a prospective multicenter randomized study including 1982 patients that underwent office diagnostic hysteroscopy in: Policlinico Abano Terme, Università Cattolica del Sacro Cuore in Rome and Ente Ecclesiastico Ospedale Generale Regionale "F. Miulli" in Acquaviva delle Fonti. They were firstly randomized according to distension medium and secondly according to instrument diameter. Pain perception after the procedure was assessed by VAS (Visual Analogue Scale) score and procedural time was registered. Mann-Whitney U test was used to compare data.

Lower pain score and procedural time were recorded with the employment of Carbon Dioxide (p < 001). Patient discomfort and procedural time were significantly influenced by the instrument diameter independent of the distension medium used, though in the subgroup where gas was employed VAS score after 1 min (VAS1) resulted lower compared to saline solution in both the traditional and mini-hysteroscopy procedures (p < 001).

Carbon dioxide and saline solution are both suitable distension media for outpatient diagnostic hysteroscopy; nonetheless, carbon dioxide confers advantages in terms of pain perception and procedural time.