Lung ultrasound-guided protocolized fluid management versus conventional central venous pressure-based management in monitoring extravascular lung water during the perioperative period of percutaneous nephrolithotomy: a randomized controlled trial

Background Percutaneous nephrolithotomy (PCNL) is a common surgical intervention to treat renal calculi. Excessive irrigation fluid absorption during surgery may enhance extravascular lung water (EVLW) level. Hence, accurate monitoring and protocolized management of EVLW are crucial for preventing postoperative complications.Methods Our randomized controlled study enrolled 181 cases undergoing elective PCNL and randomly divided them to conventional CVP-based fluid management (Group C) or lung ultrasound-guided protocolized fluid management (Group LUS). Primary outcomes included increased incidence of EVLW and severity within 30 min postoperatively and postoperative hypoxemia in the two groups. Secondary outcomes were the CVP values and LUS scores at the following time points: before irrigation (T0), at the first administration of furosemide (T1), after irrigation (T2), and at the time of leaving the post-anesthesia care unit (PACU) (T3). Moreover, included fluid volumes (crystalloid, colloid, total infusion, irrigation, and supplemental fluid at first furosemide administration), total furosemide dosage. The anesthesia time, surgical duration, PACU stay time, extubation time, and total hospital stay were recorded. Safety outcomes included perioperative complication rates.Results Compared with Group C, Group LUS demonstrated significantly lower incidence and severity of EVLW increase within 30 min postoperatively, as well as reduced postoperative hypoxemia rate (all p < 0.001). Group LUS displayed evidently lower LUS scores and CVP values at T1、T2 and T3 than Group C (p < 0.001). Moreover, extubation time and PACU stay in Group LUS were significantly reduced, compared to Group C (p < 0.05).Conclusions An LUS-guided fluid management protocol integrating real-time EVLW assessment with predefined intervention thresholds outperformed conventional CVP-based management during the perioperative period of PCNL. The superior sensitivity of LUS for detecting early EVLW elevation, combined with protocolized early intervention, reduced postoperative hypoxemia incidence, shortened extubation time and PACU stay duration, and improved short-term perioperative recovery.