Lung ultrasound in nephrology: Basics, applications, limitations, and future directions

Point-of-care ultrasonography (POCUS) is increasingly recognized as a valuable extension of the physical exam, offering real-time bedside insights to support clinical decision-making. In nephrology, lung ultrasound (LUS) is gaining prominence for its ability to assess extravascular lung water and guide fluid management, especially in patients with end-stage renal disease. This narrative review highlights current applications, technical aspects, and limitations of LUS in nephrology. Studies such as the Lung Water by Ultrasound-Guided Treatment in Haemodialysis Patients trial indicate that LUS-guided ultrafiltration may help improve blood pressure control, reduce pulmonary congestion and acute heart failure events in dialysis patients. Simplified approaches like the 8-zone protocol have shown diagnostic accuracy comparable to the traditional 28-zone method, improving feasibility in clinical practice. Nonetheless, limitations exist, including reduced specificity in non-cardiogenic lung conditions and under recognition of right-sided congestion when used in isolation. A comprehensive hemodynamic assessment requires integrating LUS with inferior vena cava ultrasound, focused cardiac ultrasound, and venous Doppler. Successful implementation depends on structured training and an understanding of potential interpretation challenges. Looking ahead, streamlined protocols, multimodal integration, and standardized training will be key to establishing POCUS as a core tool in nephrology.