Warm Versus Room Temperature Saline as a Uterine Distension Medium for Pain Reduction in Women Undergoing Outpatient Hysteroscopy: Protocol for a Randomized Controlled Trial

Overview

The goal of this randomized clinical trial is to determine whether using warmed saline at 37°C during outpatient diagnostic hysteroscopy can reduce pain compared with room-temperature saline. The study will include women aged 18 to 70 years who are undergoing outpatient diagnostic hysteroscopy. Participants will be randomly assigned to receive either warmed saline at 37°C or room-temperature saline as the fluid used to expand the uterine cavity during the procedure. Data collected will then be used to compare pain scores between the two groups during hysteroscopy and one hour after the procedure. The study will also assess whether participants require additional pain medication and whether the procedure is stopped because of severe pain. The main hypothesis is that warmed saline at 37°C will result in lower pain scores than room-temperature saline.

Outpatient diagnostic hysteroscopy is commonly performed for the evaluation of intrauterine abnormalities and other gynecological indications. Pain during hysteroscopy may be influenced by cervical manipulation, uterine distension, and uterine contractions. The temperature of the distension medium may influence patient discomfort during the procedure. This study is a parallel-group superiority randomized controlled trial designed to compare warmed normal saline at 37°C with room-temperature normal saline as the uterine distension medium during outpatient diagnostic hysteroscopy. Eligible participants will be women aged 18 to 70 years who are scheduled for outpatient diagnostic hysteroscopy and who are able to understand and report pain using a visual analog scale. Participants will provide written informed consent before enrollment. A total of 60 participants will be randomized in a 1:1 ratio to one of two study groups. The intervention group will undergo hysteroscopy using normal saline warmed to 37°C. The comparison group will undergo hysteroscopy using normal saline at room temperature. The temperature of the saline will be monitored using an infrared thermometer. Pain intensity during the hysteroscopy will be assessed using a 0-to-10 visual analog scale and will constitute the primary outcome of the study. Secondary outcomes will include pain intensity one hour after the procedure, the need for additional analgesia during or after the procedure, and the proportion of participants in whom the procedure is abandoned because of intolerable pain. The study will be conducted in the outpatient Endoscopy Unit of Demerdash Maternity Hospital, Ain Shams University. Diagnostic hysteroscopy will be performed using a 5-mm Karl Storz hysteroscope by the same senior physician. The study is designed to determine whether the use of warmed saline at 37°C provides a clinically meaningful reduction in pain compared with room-temperature saline during outpatient diagnostic hysteroscopy.