The Effect of Warmed Hysteroscopic Fluid-Distention Medium on Postoperative Core Body Temperature: A Randomized Trial (2019)

Abstract Objective: Operative hysteroscopy is considered a minimally invasive and effective treatment approach for submucosal uterine leiomyoma, endometrial polyps, Müllerian anomalies, and other conditions that result in abnormal uterine bleeding and/or infertility. Given the systemic absorption inherent in resectoscopic surgery, the primary aim of this study was to determine if warming distention-fluid medium during operative hysteroscopy performed under intravenous (IV) sedation with monitored anesthesia care would affect patients' perioperative core body temperatures, and secondarily, to assess patients' postoperative self-rated pain scores. Materials and Methods: For this single-blinded, 3-armed, stratified randomized trial (Level 2b Oxford Centre for Evidence-based Medicine Levels of Evidence 2009), 96 patients from a minimally invasive gynecologic surgery clinic in an academic-affiliated community hospital were enrolled. A computer-generated randomization sequence was used to allocate patients randomly to 3 groups. Group 1 had normal saline-distention medium-fluid bags at room temperature, defined as 22°C (71.6°F). Group 2 had fluid bags pulled from a warming-cabinet set at 40°C (104°F) as standardized by the Joint Commission on National Quality Approval. Group 3 had continuously warmed fluid by an automated fluid-management system with a function that warms the distention medium to 40°C (104°F) continually. Randomization was stratified by procedure type (myomectomy and nonmyomectomy), so that 50% of the cases for each fluid-temperature category included resections of submucosal leiomyomas. Pre- and postoperative near-core body temperatures and pain scores; operative times; and hysteroscopic fluid temperatures, pressures, and fluid deficits were recorded. Intention-to-treat analysis was performed. Results: There was no statistically significant differences among the 3 arms of the trial for the primary outcome of near-core body temperature or for the secondary outcome of self-rated pain scores. However, when comparing patients undergoing hysteroscopic myomectomy with patients undergoing nonmyomectomy hysteroscopic procedures, there were higher fluid deficits and operative times in the hysteroscopic myomectomy patients in groups 1 and 2 (room-temperature fluid and passively warmed fluid, respectively), but not in group 3 (continuously warmed fluid). Group 3 had no statistically significant differences in average fluid deficit, when comparing hysteroscopic myomectomy to all other procedure types. This finding held true although there was no statistically significant differences in total procedure times between the myomectomy procedures and all other surgical procedure types within group 3. Conclusions: Warming hysteroscopic distention media did not affect near-core body temperature or postoperative pain scores. Use of continuously warmed hysteroscopic fluid in hysteroscopic myomectomy might decrease operative times as well as volume of hysteroscopic fluid deficits. Use of an automated fluid-management system that has the capacity to warm fluid-distention medium continuously can be advantageous to gynecologic surgeons, as this intervention is simple, low-cost, and safe. Further studies to assess the relationship between the temperature of distention medium and surgical outcomes are recommended, specifically surrounding the relationship between operative times and fluid absorption.