Minimum intrauterine pressure required for uterine distention

Study Objective. To determine the minimum intrauterine pressure required to distend the uterine cavity during hysteroscopy using saline as a distending medium. Design. Nonrandomized, prospective study (Canadian Task Force classification II-2). Setting. Ambulatory surgery suites. Patients. Seven women from the practice of the principal investigator. Intervention. Hysteroscopy was performed and intrauterine perfusion pressure was measured. Measurements and Main Results. Intrauterine perfusion pressure required to separate the anterior and posterior uterine walls was measured using a Cobe CDX pressure transducer kit. The uterine cavity was distended when intrauterine perfusion pressure reached a median of 40 mm Hg (range 25-50 mm Hg). Conclusion. This preliminary study suggests that a liquid with the same viscosity as normal saline distends the uterine cavity at a pressure of approximately 40 mm Hg. This pressure is lower than that at which spillage from fallopian tubes occurs, suggesting that it may theoretically be possible to ablate the endometrial lining with heated liquid without spilling liquid into the peritoneal cavity. Further study with larger numbers of patients is required to verify this finding.