Impact of intraoperative tidal volume on surgical parameters during flexible ureteroscopy.

To investigate the impact of intraoperative tidal volume on surgical efficiency and outcomes in patients undergoing flexible ureteroscopy (fURS). This prospective cohort study included adult patients with unilateral, solitary renal stones located in the upper or middle calyx or in the renal pelvis. Patients were divided into two groups based on intraoperative tidal volume settings. Demographic factors, stone features, operative metrics, laser efficiency, complication rates, and hospital stay were compared. A total of 70 patients were included (median age: 49 years). Forty-two patients (60%) had a tidal volume ≥ 500 mL (Group 1) and 28 (40%) had a tidal volume < 500 mL (Group 2). Baseline characteristics, including age, ASA score, BMI, comorbidities, stone size, volume, density, laterality, and location, were comparable between groups, except for a higher proportion of males in Group 1 (p < 0.001). Operative time and lasing time did not differ significantly between groups. Total lasing energy was higher in Group 1 (p = 0.046), while laser efficiency was significantly greater in Group 2 (p = 0.031). Intraoperative ventilatory parameters and postoperative outcomes, including stone-free rates, infection rates, and hospital stay, were similar between groups. Within physiological limits, lower tidal volumes were associated with higher laser efficiency, an exploratory metric, and lower total laser energy, without adversely affecting operative time, stone-free rates, or perioperative safety. Low tidal volume ventilation was associated with differences in laser efficiency parameters during fURS; however, these findings should be interpreted as exploratory and hypothesis-generating.