Risk factors of high fluid absorption in patients treated with mini-PCNL: a single-center prospective study.

Background: The factors influencing fluid absorption in mini-percutaneous nephrolithotripsy (mini-PCNL) are still unknown. We aim to investigate the factors that influence irrigation fluid absorption during mini-PCNL.

Methods: A total of 94 patients who underwent mini-PCNL were included in this prospective study. The endoscopic surgical monitoring system (ESMS) was used to measure the volume of irrigation fluid absorbed during the procedure. Irrigating time, the total volume of irrigation fluid, stone size, S.T.O.N.E. score, hemoglobin, electrolyte levels, and postoperative complications were recorded.

Results: A significant correlation was observed between fluid absorption and the presence of postoperative fever, and based on this phenomenon, patients were divided into low and high fluid absorption groups. The serum creatinine level in the high fluid absorption group was significantly high (7 vs. 16.5, p = 0.02). Significant differences were observed between the low and high fluid absorption groups in terms of mean stone size (21.70 mm vs. 26.78 mm), presence of stone burden ≥ 800 mm (4% vs. 23%), S.T.O.N.E. score > 8 (4% vs. 38%), the fluid used > 18,596 ml (19% vs. 78%), irrigation time (55.61 min vs. 91.28 min), and perfusion rate (24% vs. 45%) (all p < 0.05). The rates of postoperative fever and SIRS in the high fluid absorption group were significantly high (p < 0.05).

Conclusions: Mean stone size, presence of stone burden ≥ 800 mm, S.T.O.N.E. score > 8, the fluid used > 18596 mL, irrigation time, and perfusion rate are risk factors of intraoperative fluid absorption in mini-PCNL.