Fluid deficit-related complications in hysteroscopic surgery using normal saline as distension medium: a retrospective analysis of four surgical modalities and risk factors

Objective To compare fluid deficit volumes across four hysteroscopic procedures using normal saline as distension medium, identify risk factors for excessive fluid deficit, and evaluate the impact of intrauterine pressure settings on fluid-related complications. Design Retrospective cohort study. Setting Department of Day Care, Gansu Provincial Maternity and Child-care Hospital (Gansu Provincial Central Hospital), a tertiary referral center. Participants A total of 422 patients underwent hysteroscopic surgery for intrauterine lesions between January 2022 and January 2025, including 62 transcervical resection of adhesions (TCRA), 170 hysteroscopic endometrial resection (HER), 80 transcervical resection of septum (TCRS), and 110 transcervical resection of myoma (TCRM) procedures. Interventions All procedures were performed using normal saline as distension medium. Intrauterine pressure was set at either 80 mmHg or 100 mmHg at the surgeon’s discretion. Results The primary outcome was distension fluid deficit volume. TCRM had the highest median absorption (700.0 mL, IQR 580–800) compared with TCRA (156.8 mL), HER (312.4 mL), and TCRS (278.5 mL) ( P < 0.001). Fluid overload events (pulmonary edema or ICU admission) occurred exclusively in the TCRM group (5/110, 4.5%, P = 0.005). Exploratory ROC analysis suggested a candidate threshold of 750 mL for predicting fluid-related adverse events (AUC 0.741, 95% CI 0.641–0.842). However, given the limited number of fluid-related adverse events, a clinically relevant threshold of 1000 mL was used for the primary risk factor analysis. Multivariable logistic regression identified FIGO type 2 myoma ( OR 3.60, 95% CI 1.01–12.81), operating time ≥ 60 min (OR 6.42, 95% CI 1.64–25.12), and distension pressure 100 mmHg ( OR 4.64, 95% CI 1.32–16.32) were associated with excessive absorption in this exploratory analysis. However, the non-randomized assignment of pressure limits causal interpretation, and these findings require prospective validation. Conclusion Transcervical resection of myoma (TCRM) is associated with the highest risk of fluid deficit among hysteroscopic procedures performed with normal saline. FIGO type 2 myoma, prolonged operative time, and higher distension pressure (100 mmHg) are independent predictors of excessive fluid deficit. These findings support the use of lower intrauterine pressure (80 mmHg) as a safe and cautious initial approach during TCRM. The candidate threshold for excessive fluid deficit identified in this study requires prospective validation.