Predictors of Infused Distending Fluid Volume in Hysteroscopic Myomectomy

Background and Objectives: The use of a bipolar resectoscope has become popular due to the lower risk of hyponatremia. However, gynecologists might overlook the risk of water intoxication. Water intoxication is associated with the infusion of distending fluid. We were interested in the prediction of the infused distending fluid volume in the era of bipolar hysteroscopy. Thus, the aim of this study was to identify the predictors of the infused distending fluid volume for hysteroscopic myomectomy. Materials and Methods: All consecutive women who underwent monopolar (n = 45) or bipolar (n = 137) hysteroscopic myomectomy were reviewed. Results: Myoma diameter (cm, coefficient = 680 mL, 95% confidence interval (CI) = 334-1025 mL, p <0.001) and bipolar hysteroscopy (coefficient = 1629 mL, 95% CI = 507-2752 mL, p = 0.005) were independent predictors of infused distending fluid volume. A myoma diameter ≥4.0 cm was the optimal cutoff value to predict the presence of >5000 mL of infused distending fluid. One woman in the bipolar group developed life-threatening water intoxication. Conclusions: Myoma diameter is associated with an increase in infused distending fluid volume, especially for myomas ≥4 cm. Meticulous monitoring of the infused distension fluid volume is still crucial to avoid fluid overload during bipolar hysteroscopic myomectomy.