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

Abstract

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.

Key Words: Point-of-care ultrasonography; Ultrasound; B-lines; Nephrology; Dialysis; Heart failure

Core Tip: Point-of-care ultrasonography, especially lung ultrasound (LUS), is becoming an essential bedside tool in nephrology. It enables dynamic, noninvasive assessment of fluid status and extravascular lung water, particularly in dialysis patients. Evidence from trials like Lung Water by Ultrasound-Guided Treatment in Haemodialysis Patients highlights its potential to guide ultrafiltration, improve blood pressure control, and reduce heart failure events. Simplified protocols, such as 8-zone LUS, offer diagnostic efficiency with greater feasibility. However, LUS should not be used in isolation. Combining it with other modalities like inferior vena cava, cardiac, and venous Doppler ultrasound ensures a more accurate hemodynamic picture.

INTRODUCTION

Point-of-care ultrasonography (POCUS) refers to the use of ultrasound at the patient’s bedside by clinicians to answer specific clinical questions and support real-time decision-making in patient care[1,2]. Technological advancements like equipment miniaturization, improvement in image quality, integration of artificial intelligence, combined with the efforts of visionary physicians have propelled POCUS to become an important aspect of the physical exam in recent years and is commonly being cited as the fifth pillar to bed side physical examination. Today, it is being incorporated into almost every medical and surgical specialty and is becoming a standard element of both undergraduate and graduate medical education[3-5].

Confined to procedural guidance in nephrology for years, POCUS is now increasingly recognised for its broader diagnostic potential and comprehensive hemodynamic assessment[3,6]. The growing interest in the use of extra-renal POCUS among nephrologists for assessing hemodynamic status, partly driven by the expanding body of research on lung ultrasound (LUS) in patients with end-stage renal disease (ESRD). The seminal Lung Water by Ultrasound-Guided Treatment in Haemodialysis Patients (LUST) study and its sub-studies have highlighted the shortcomings of the traditional physical exam for hemodynamic status assessment in haemodialysis patients. These studies suggest that LUS, when used to guide ultrafiltration, can enhance blood pressure management and reduce the incidence of acute heart failure episodes[7-10].

Furthermore, due to its ease of use, high diagnostic accuracy, and strong prognostic value, LUS is evolving as a valuable addition to the nephrologist’s bedside toolkit[6,11]. However, effective use depends on a solid understanding of anatomy, attention to technical factors, and appropriate clinical integration[11-13]. Through this narrative review, we aim to give a basic introduction into LUS and discuss the current understanding regarding its applications, limitations, and practical considerations in the field of nephrology whilst exploring more novel uses.

TECHNICAL ASPECTS OF LUS

In everyday clinical practice, LUS typically uses an 8-zone scanning protocol, dividing each hemithorax into four zones based on key anatomical landmarks: The parasternal, anterior axillary, and posterior axillary lines, along with a horizontal line at the level of the third intercostal space. This creates eight zones in total - four on each side: Upper anterior, lower anterior, upper lateral, and basal lateral. These zones are strategically chosen, for instance, air rises, so pneumothorax is best assessed in the anterior zones, while dependent edema and pleural effusions are commonly detected in the lateral zones. Although this 8-zone protocol is commonly used, most published data in the ESRD population are based on the more comprehensive 28-zone approach. This method evaluates 16 intercostal spaces on the right and 12 on the left, with fewer zones on the left due to the heart’s position (Figure 1). It’s important to note that, unlike cross-sectional imaging like computed tomography, LUS cannot visualize the entire lung. Localized issues such as small consolidations or infarcts, as well as lesions that do not extend to the pleural surface, like masses, may be missed. That said, this zonal approach is generally sufficient for nephrology-related applications, particularly assessing extravascular lung water (EVLW)[14]. From an equipment standpoint, LUS can be performed using low-cost ultrasound machines, including handheld devices equipped with phased array or curvilinear transducers. Some handhelds also feature integrated all-in-one probes.

Figure 1 Lung ultrasound zones. A: Twenty-Eight-zone method: 16 intercostal spaces on the right and 12 on the left are examined; B: Eight-zone lung ultrasound: Four zones in left hemithorax. In this method, each zone may include more than one intercostal space.

A unique feature of LUS, in terms of image interpretation is that, unlike most other organs, normal air-filled lungs do not appear as distinct tissue structures on ultrasound. Instead, interpretation relies primarily on recognizing artifacts. This is because the significant acoustic impedance mismatch between soft tissue and air causes most of the ultrasound waves to reflect at that interface. This same principle explains why gel is necessary for body surface imaging. On the bright side, this reliance on artifacts often makes LUS more approachable for novice POCUS users.

In a well-aerated lung, ultrasound reveals a bright horizontal pleural line that moves with respiration, a finding known as pleural sliding. A-lines, which are repeating horizontal artifacts, typically appear at regular intervals and are seen in this context (Figure 2A). These reverberation artifacts result from the repeated reflection of ultrasound waves between two strong reflectors, namely the pleural line and the ultrasound probe. The presence of A-lines indicates normal lung aeration and is characteristic of healthy lungs or non-interstitial conditions such as obstructive airway diseases or pneumothorax. In pneumothorax, however, pleural sliding is absent[15,16].

Figure 2 Lung ultrasound images showing. A: Normal horizontal artifacts known as A-lines (indicated by arrows); B: Discrete B-lines (arrows); C: Confluent B-lines creating a white-out appearance in the scanned lung zone typically seen in alveolar edema. The arrowhead in each image indicates the pleural line.

When the underlying lung becomes denser due to the replacement of air with fluid, blood, collagen, or other material, the acoustic mismatch between the pleura and lung tissue decreases. This change enhances the transmission and reflection of ultrasound waves, leading to the generation of vertical artifacts known as B-lines. These ‘ring-down artifacts’ result from the to and fro movement of the ultrasound beam within the altered lung parenchyma and are indicative of interstitial or alveolar involvement (Figure 2B and C)[15]. These are vertical, laser-like hyper-echoic artifacts that extend to the bottom of the screen without fading, moving synchronously with lung sliding. The appearance of multiple B-lines (three or more per intercostal space) in each zone is considered pathologic and indicates increased lung density or EVLW[15,16].

APPLICATIONS OF LUS IN NEPHROLOGY

The adoption of LUS as a bedside diagnostic tool addresses a critical need in nephrology for accurate, timely, and non-invasive assessment of fluid status in patients with kidney disease. Traditional methods such as physical examination and intake-output data often lack sensitivity, leading to potential mismanagement of volume disorders[17]. Its portability, ease of use, and absence of radiation makes LUS relevant for repeated assessments in vulnerable populations, such as those with ESRD[18].

Studies have also demonstrated that LUS is more effective than chest radiography and physical examination in detecting various pulmonary conditions such as pneumothorax, pneumonia, and pleural effusion, with cardiogenic pulmonary edema being of particular interest[15,17,19]. The IAPN position statement also recognizes LUS as a core element of the nephrology POCUS training curriculum to aid in hemodynamic assessment[3].

Data indicate that pulmonary congestion is highly prevalent among patients with ESRD receiving hemodialysis, and worsening congestion is associated with increased cardiovascular events and mortality[7]. A landmark study by Noble et al[20] showed that pulmonary congestion, measured by B-line scores, progressively declined in parallel with the volume of ultrafiltration during a single dialysis session. This real-time resolution of B-lines in 28-lung zones, from a median of 17.5 pre-dialysis to 3.5 post dialysis suggested, LUS could serve as a practical biomarker for tracking efficacy of fluid removal. These findings raised the hypothesis that LUS-guided ultrafiltration might optimize dry weight management by identifying patients who could safely tolerate additional fluid removal without inducing intradialytic hypotension or other complications.

To answer this question, Zoccali et al[10] did a randomized multi-center trial termed LUST study in which patients with ESRD, and elevated cardiovascular risk were randomized to either a LUS-guided intervention arm or a standard care arm[7,8,10]. In the intervention group, investigators used a 28-zone LUS protocol to quantify B-lines as a marker of pulmonary congestion. A B-line count greater than 15 was used to define significant lung congestion, prompting clinicians to adjust ultrafiltration and, if necessary, antihypertensive therapy to achieve decongestion. Nephrologists performing the scans underwent a structured remote training program to ensure reproducibility and accuracy. Patients were followed for 24 months, and primary outcomes included a composite of all-cause mortality, non-fatal myocardial infarction, and de novo decompensated heart failure. Secondary and post hoc analyses assessed recurrent heart failure admissions and cardiovascular events. After a mean follow-up of 1.5 years, there was no statistically significant difference in the primary composite endpoint, with a hazard ratio of 0.88 (95%CI: 0.63-1.24)[10].

Although the LUST study was ultimately negative in terms of primary composite endpoint, it demonstrated that implementing an ultrafiltration strategy guided by ultrasound was both safe and effective in alleviating pulmonary congestion among participants. In the intervention arm, the median B-line count from 28 lung zones declined from 15 (95%CI: 12-19) at baseline to 9 (95%CI: 5-12) after treatment. Conversely, the control arm showed an increase from 16 (95%CI: 13-20) to 30 (95%CI: 20-39). The frequency of arrhythmic events was comparable between groups—11.6/100 person-years (95%CI: 7.8-16.4) in the intervention cohort vs 12.5/100 person-years (95%CI: 8.6-17.4) in the control cohort (P = 0.76), indicating that the approach did not raise safety concerns. A Post hoc analysis also revealed a lower rate of recurrent decompensated heart failure in the intervention group 0.37 (95%CI: 0.15-0.93), with fewer hospital readmissions and longer time to first rehospitalization, suggesting a potential longer-term clinical benefit of ultrasound-guided ultrafiltration in select patients[10].

Additionally, a sub-study within the LUST trial, which included 71 hypertensive patients who were clinically euvolemic found that LUS-guided ultrafiltration led to greater improvements in ambulatory blood pressure than conventional management. The average systolic pressure fell by approximately 6.6 mmHg compared with a 0.7 mmHg reduction in the control group, while diastolic pressure decreased by about 3.9 mmHg vs roughly 0.6 mmHg, respectively[8]. In contrast to the findings of a previous study where vascular access complications were a major driver of morbidity and hospitalization in patients undergoing ultrafiltration[21], there was no evidence of a rise in vascular access complications, with events occurring in roughly nine cases per hundred patient-years in the intervention arm (95%CI: 6.0-13.7) compared with about seven cases per hundred patient-years in those receiving standard care (95%CI: 4.2-10.9). Moreover, unlike another prior trial, where dry-weight reduction led to higher rates of cramps, dizziness, and hypotension, dialytic symptoms were not more frequent[22], and dialysis hypotension was less frequent in the intervention group, with 3.2 incidents per 100 person-years (95%CI: 3.00-3.42) compared to 4.73 per 100 person-years (95%CI: 4.48-5.50) in the usual care group (P < 0.001).

If these findings are confirmed in future larger studies, a reliable management protocol for pulmonary congestion and reducing acute heart failure visits could be a significant breakthrough[11]. However, implementing LUS techniques in a real-world dialysis setting presents challenges. Many have criticized LUS as cumbersome due to the 28-zone approach, with some experts labeling it "time and personnel intensive"[23]. To address this, recent research on LUS-guided volume management has focused on simplifying the process, using fewer lung zones, incorporating machine learning for faster interpretation, and involving ancillary staff or even patients in performing and interpreting the studies[11].

Several studies indicated that the traditional 28-zone LUS is probably not necessary in routine clinical practice[24-27]. Torino and colleagues reanalyzed data from 303 of the original 392 patients in Zoccali's observational hemodialysis cohort and found that a simplified 8-zone LUS strongly correlated with the full 28-zone method, showing a correlation coefficient of ρ = 0.93 (P < 0.001) and a good level of agreement, with a concordance of k = 0.79[24]. At a minimum, a 4-zone LUS assessing the upper anterior and lower lateral regions of bilateral lungs is sufficient to guide diuresis in heart failure or ultrafiltration in patients undergoing hemodialysis[11]. In our clinical practice, we routinely perform an 8-zone LUS examination, as described previously. Some ultrasound devices offer automated B-line quantification that produces a zonal summary, as illustrated in Figure 3. This feature facilitates standardized documentation and helps track changes in pulmonary congestion over time by allowing easy comparison with previous studies.

Figure 3 Eight-zone B-line summaries obtained using a handheld ultrasound device (Philips Lumify^®) in a patient with end-stage kidney disease. A: Pulmonary edema following a missed hemodialysis session, with three or more B-lines counted by the machine in each lung zone; B: Marked improvement after 35 liters of ultrafiltration, now showing only one to two B-lines per zone, though there remains potential for further improvement with additional fluid removal.

The usefulness of LUS in evaluating pulmonary congestion extends beyond patients with ESRD or those on hemodialysis. Multiple studies have demonstrated its diagnostic and prognostic value in heart failure and intensive care unit populations, both highly relevant to nephrology practice[28,29]. LUS has demonstrated superior diagnostic accuracy for acute heart failure compared to traditional clinical assessments, such as history, physical examination, and arterial blood gas with reported sensitivity between 94%-97% and specificity around 97% in patients admitted with acute dyspnea[30,31]. Repeated LUS examinations help guide diuretic therapy, resulting in quicker decongestion and possibly shorter hospital stays[32-34]. Notably, a reduction in B-lines, indicating improved pulmonary congestion during heart failure hospitalization has been associated with better outcomes, including lower rates of all-cause mortality and rehospitalization for acute heart failure at six months[32,35].

Several clinical trials have compared LUS-guided management with usual care in patients with congestive heart failure. Among these, the LUS-HF and CLUSTER-HF trials were similar in design, enrolling 123 and 126 hospitalized patients with heart failure, respectively, including both heart failure with reduced ejection fraction and heart failure patients have preserved ejection fraction phenotypes[36,37]. The participants were randomized to either a standard care group (control) or a group guided by LUS. The LUS protocol involved the 8-zone method with a handheld ultrasound device. Pulmonary congestion was defined as the presence of more than three B-lines in total. In the LUS-guided group, physicians were encouraged to integrate ultrasound findings with their clinical assessment to tailor diuretic therapy. After a six-month follow-up, both trials demonstrated similar outcomes, showing a significant reduction in the primary endpoint—mainly driven by fewer urgent heart failure-related visits—without differences in mortality or hospitalization rates[36,37].

Another Italian study involving 244 ambulatory patients with HFrEF used a LUS protocol that scanned the apical, middle, and basal lung fields from the parasternal to the midaxillary line. Congestion severity was scored based on the highest lung field showing B-lines: 1 point if limited to the basal fields, 2 points if extending to the middle fields, and 3 points if reaching the apices. LUS findings were incorporated into clinical decision-making, particularly for diuretic adjustment. After three months of follow-up, the LUS-guided group had significantly fewer hospitalizations for acute decompensated heart failure, though mortality did not differ between groups[38].

While these three studies focused on identifying subclinical congestion in outpatient populations, another trial evaluated LUS for guiding decongestion in patients presenting to the emergency department with acute decompensated heart failure. The intervention involved a LUS-guided decision to administer an additional dose of diuretics six hours after enrollment. Although all patients in the LUS group received this extra dose, 92% of the control group did as well. Given the similarity in management between groups, the trial unsurprisingly yielded a neutral outcome[39]. In critical care and inpatient settings, protocols like the bedside lung ultrasound in emergency aid in differentiating causes of respiratory distress such as pulmonary edema, pneumothorax, acute respiratory distress syndrome, and pneumonia[15]. These findings emphasize the value of LUS in identifying subclinical congestion as well as undifferentiated dyspnea, rather than obvious fluid overload. This is particularly relevant in nephrology, where patients are often seen later during hospitalization, after multiple empiric treatments, when volume status is less clear.

LIMITATIONS OF LUS

Quantitative LUS has inherent shortcomings when used in isolation for assessing congestion[11]. Generalizing results and interpreting findings out of context can lead to patient mismanagement. For instance, one study found that critically ill patients on dialysis who showed an A-line pattern on POCUS were more likely to experience intradialytic hypotension compared to those with a B-line pattern[40]. However, the practical significance of this finding is questionable, as A-lines reflect a normal lung pattern like normal breath sounds on auscultation and are not directly associated with changes in blood pressure. Restricting ultrafiltration to patients demonstrating B-lines, indicative of increased EVLW, while adopting a conservative approach for those with A-line patterns, would result in the under-recognition of a substantial subset of fluid-overloaded individuals as this approach overlooks the contribution of right heart function and the presence of elevated right atrial pressure and systemic venous congestion, factors that are independently associated with adverse clinical outcomes[39,40]. This is especially relevant in patients with chronic heart failure, where augmented lymphatic drainage may reduce pulmonary edema, even as venous congestion continues to be present[41].

Furthermore, B-lines are not always indicative of cardiogenic pulmonary edema and may also be seen in parenchymal lung diseases, such as pulmonary fibrosis, where interstitial septal thickening occurs. Other alveolar filling conditions, including pneumonia and acute respiratory distress syndrome, can likewise demonstrate B-lines (Figure 4).

Figure 4  Illustration demonstrating that B-lines are not specific to cardiogenic pulmonary edema.

Pleural line irregularities, diminished lung sliding, patchy spared regions, and subpleural consolidations are useful sonographic clues for differentiating pneumogenic from cardiogenic pulmonary edema (Figure 5). Nonetheless, distinguishing between the two entities is often difficult when they occur simultaneously. In those circumstances, Doppler-based assessment of left ventricular filling pressures can offer additional diagnostic guidance[42,43].

Figure 5 Lung ultrasound images showing. A: Confluent B-lines with a thickened, irregular pleural line (arrow) in a patient with acute respiratory distress syndrome; B: A high-resolution image obtained using a linear transducer, highlighting subpleural consolidation (arrow).

It is also noteworthy that Pulmonary hypertension and right ventricular dysfunction are often seen in dialysis patients, particularly in those with brachial arteriovenous fistulas, and are linked to poorer outcomes[44-46]. Therefore, a complete hemodynamic evaluation in this group should include assessment of right heart function. Right atrial pressure can be estimated using inferior vena cava or internal jugular vein ultrasound, and Doppler assessment of systemic venous congestion may be added when clinically appropriate[47,48]. Focused cardiac ultrasound should also be performed to identify hemodynamically significant pericardial effusion, left ventricular hypertrophy, or major valvular disease as part of the overall bedside assessment. In real-world practice, we use LUS as just one part of a broader bedside hemodynamic assessment. Our algorithmic approach has been described in detail elsewhere for those interested in exploring it further[49]. This is well within the capabilities of nephrologists who are appropriately trained in the technique[3]. Table 1 provides a comparison of commonly used tools for hemodynamic assessment familiar to nephrologists, highlighting the strengths and limitations of each, including LUS.

Table 1 Commonly used methods to assess hemodynamic status in nephrology practice.

Method	Strengths	Limitations
Physical exam	Standard bedside evaluation: Does not require additional training for physicians; Positive findings are typically clinically meaningful	Very limited sensitivity; may fail to detect a substantial number of patients with volume overload
Body weight	Short-term weight changes can indicate fluid accumulation or loss; Can be self-monitored by the patient at home	Inaccurate readings may result from improper calibration, use of different scales, or inconsistent techniques such as wearing varying amounts of clothing during each measurement; Weight changes may not capture congestion related to fluid redistribution
Intake-output documentation	Provides an overview of the patient’s fluid balance	Documentation errors are common, especially outside the intensive care setting; Does not capture congestion resulting from fluid redistribution
Continuous hematocrit monitoring	Delivers real-time insights into relative changes in intravascular blood volume, enabling adjustment of ultrafiltration rate and volume accordingly	Use is limited to patients receiving hemodialysis; Typically operated by nurses or technicians, requiring dedicated staff training; Does not evaluate tissue congestion, extravascular lung water or cumulative fluid burden
Bioimpedance	Offers information on total body, extracellular, and intracellular water, allowing for calculation of both absolute and relative fluid overload	Unable to distinguish between compartmentalized edema (such as ascites, pericardial, or extravascular lung water) and overall increased total body water; Does not provide information on intravascular volume
Right heart catheterization	Offers detailed assessment of hemodynamic parameters including right atrial pressure, pulmonary artery pressure, pulmonary capillary wedge pressure, pulmonary vascular resistance, and cardiac output	Invasive modality, generally limited to specialized intensive care settings; Does not assess the presence or absence of extravascular lung water, as elevated pressures do not always correlate with volume overload; Lacks information on the degree of venous congestion; Susceptible to errors from incorrect transducer calibration, leveling, zeroing, or improper balloon inflation; Most nephrologists are not adequately trained to interpret waveforms or recognize measurement errors
IVC POCUS	Estimates right atrial pressure; Relatively simple to perform and can be learned with brief training	Estimating right atrial pressure using IVC POCUS is unreliable in mechanically ventilated patients; A plethoric IVC is not specific to volume overload and may be seen in conditions such as cardiac tamponade, pulmonary embolism, tricuspid regurgitation, or pulmonary hypertension; A small, collapsible IVC cannot distinguish between hypovolemia, euvolemia, or high cardiac output states; IVC may appear small and collapsed despite elevated right atrial pressure in cases of intra-abdominal hypertension; IVC collapsibility is influenced by the strength of respiratory effort, which varies significantly among patients, limiting the real-world applicability of standardized cutoffs from studies
Internal jugular vein POCUS	Estimates right atrial pressure; Especially helpful when the IVC is difficult to visualize or yields unreliable information, such as in patients with cirrhosis	Susceptible to errors from improper bed positioning, excessive transducer pressure, and off-axis imaging; The assumption that right atrial depth is consistently 5 cm from the sternal angle has been shown to be inaccurate - often requires concurrent focused cardiac ultrasound to determine this; Scanning protocols vary across the literature, limiting standardization
Lung ultrasound	Identifies and quantifies extravascular lung water; More sensitive than chest X-ray for detecting cardiogenic pulmonary edema; Can be performed using basic, lower-cost ultrasound equipment	B-lines are not specific to pulmonary edema and may also appear in conditions such as lung fibrosis, infections, or contusions; In certain cases, distinguishing between cardiogenic and non-cardiogenic pulmonary edema requires concurrent assessment of left ventricular filling pressures using cardiac Doppler ultrasound (an advanced POCUS skill)
Venous Doppler/VExUS (hepatic, portal, intrarenal, and femoral veins)	Detects and quantifies systemic venous congestion; Enables monitoring the response to decongestive therapy through repeat assessments	It is an advanced skill that requires competence in Doppler ultrasound; Lack of simultaneous ECG may limit interpretation, particularly the hepatic vein waveform; Does not differentiate pressure and volume overload; Requires mid- to high-end ultrasound equipment with ECG capability
Focused cardiac ultrasound	Offers insights into cardiac function, chamber size, pericardial effusion, and major valvular abnormalities; Experienced users can also estimate stroke volume, pulmonary artery pressure, and left ventricular filling pressures	Considered an advanced skill; nephrologists performing Doppler assessments typically require formal certification in critical care echocardiography; Requires mid- to high-end ultrasound equipment; Accuracy depends on adequate acoustic windows, which are affected by factors such as patient body habitus, positioning, and operator expertise

IVC: Inferior vena cava; ECG: Electrocardiogram; POCUS: Point-of-care ultrasonography.

CONCLUSION

With the growing integration of POCUS into routine clinical practice, future research should aim to further define and optimize the role of LUS in combination with other POCUS modalities and objective clinical metrics. For example, LUS in nephrology should prioritize its integration with complementary parameters such as venous excess ultrasound and focused cardiac ultrasound to create multidimensional hemodynamic profiles that guide personalized decongestion strategies. Over the next few years, guidelines should evolve focusing on multi organ POCUS for assessing hemodynamic status. Streamlining protocols (e.g., abbreviated LUS zones) could enhance clinical adoption while maintaining prognostic accuracy, enabling faster diagnosis of pulmonary congestion and reducing time for therapeutic intervention. Additionally, research should explore how real-time ultrasound visualization improves patient engagement by demonstrating objective evidence of fluid overload, fostering adherence to treatment plans. However, addressing training gaps and standardizing interpretation thresholds remain critical to maximizing its practical utility in routine nephrology practice.