Chronic kidney disease (CKD) is defined as an abnormality of kidney structure or function that occurs for at least 3 months, characterized by a decrease in the glomerular filtration rate (GFR) <60 ml/minute/1.73 m2 and has a negative impact on health. The CKD classification system is based on 3 categories, namely cause (C), Glomerular Filtration Rate (GFR), and degree of albuminuria (A), abbreviated as CGA. Kidney failure is defined as patients with stage 5 CKD. ¹

Progressive loss of glomerular filtration function leads to fluid retention, leading to fluid overload. This condition can manifest as pulmonary congestion, which is common in patients with kidney failure. Fluid overload typically causes symptoms in kidney failure and is often associated with underlying conditions, such as hypertension, congestive heart failure, and left ventricular hypertrophy. Fluid overload, or hypervolemia, is a significant problem that frequently occurs in patients with chronic kidney disease, with increasing morbidity and mortality. It can be seen in both non-dialysis and dialysis patients. ^{2, 3}

A study by Khan et al., ⁴ which examined patients with non-dialysis kidney failure, showed that the most common fluid status in these patients was hypervolemia at 43.4%, while euvolemia and hypovolemia were next at 36.2% and 20.5%, respectively.

Patients with volume overload status have been shown to have a negative impact on the progression of kidney failure. Research by Hung et al. ⁵ showed that non-dialysis kidney failure patients with fluid overload experienced a significantly worsening glomerular filtration rate compared with kidney failure patients without fluid overload (~4.3 ml/min/1.73 m2/year vs. ~1.7 ml/min/1.73 m2/year).

Numerous objective methods, from the non-invasive tools such as spirometry, chest X-ray, natriuretic peptide measurement, blood volume monitoring, and bioimpedance analysis (BIA), have been extensively investigated to assess volume status and management in dialysis patients with kidney failure. Research conducted by Fikry et al. ⁶ showed that the failure rate of spirometry was only 1.9% and the adverse event rate was only 0.44%. However, all these methods possess significant limitations and yield unsatisfactory outcomes when employed in isolation. ^{6, 7}

Lung ultrasound (LUS) has been shown to effectively assess pulmonary congestion. It is non-invasive, radiation-free, and can be performed at the bedside by experienced operator. Lung ultrasound can evaluate extravascular lung fluid volume by identifying the B-line. This finding not only quantitatively and qualitatively evaluates lung fluid volume status but also assesses the effectiveness of hemodialysis therapy by observing the B-line: its disappearance indicates effective fluid removal through the hemodialysis process. ^{8– 10}

Research conducted by Kaysi, et al. ¹¹ showed that improvement in pulmonary congestion as assessed by a decrease in the total B-line value can be seen since the initiation of hemodialysis (pre-dialysis: 16 ± 5.53 and post-dialysis: 15.3 ± 6.63) and continues to be seen after the second hemodialysis (pre-dialysis: 16.3 ± 5.27 and post-dialysis: 13.6 ± 5.83). This study also stated that a significant decrease in the total B-line was seen after 1 month since undergoing hemodialysis initiation (17.4 vs 8.5, p < 0.0001).

Assessing the degree of pulmonary congestion in patients with kidney failure undergoing hemodialysis initiation is crucial for assessing the success of hemodialysis. Lung ultrasound is a potentially useful modality due to its relatively rapid and sensitive performance. However, few studies have assessed the degree of pulmonary congestion before and after hemodialysis initiation, which is the rationale for this study.

Fluid retention is a major problem in patients with kidney failure. A multitude of reasons contribute to this phenomenon, including a progressive decline in glomerular filtration rate, activation of the renin-angiotensin-aldosterone system, and concomitant cardiovascular diseases, all of which result in sodium and water retention. This volume expansion due to fluid retention increases the heart's workload, coupled with ventricular hypertrophy and arterial stiffness, common in patients with long-standing hypertension that often accompany kidney failure. This creates a mutually exacerbating cycle between kidney failure and cardiovascular disease. ^{5, 12} A study by Tsai et al. ²⁰ demonstrated a significant positive association between pulmonary congestion and an increased risk of initiation of hemodialysis in patients with kidney failure. Therefore, pulmonary congestion is not only a clinical manifestation but also an indicator of worsening kidney function.

Lung ultrasonography is a method for assessing pulmonary congestion that has been widely studied in recent years. This technique is easy to perform, fast, radiation-free, and can be performed in real time at the patient's side. Research conducted by Mallamaci et al. ²¹ showed that lung ultrasonography has fairly good intraprobe reproducibility; meaning the results obtained will be more or less the same even if performed by different researchers with different equipment. Research shows that the presence of B-lines on lung ultrasound is closely associated with the occurrence of fluid overload, reflected by high EVLW (r = 0.91, p 0.0001). Study by Enghard et al. ²² showed that B-lines >1.5 had a sensitivity of 92.1% and a specificity of 91.7% for detecting fluid overload (AUC: 0.9419). ^{22, 23}

In this study, a total of 61 subjects with kidney failure that underwent initiation of hemodialysis and who met the inclusion criteria were obtained from at Wahidin Sudirohusodo Hospital during the period of May – September 2025. The proportion of female subjects was higher at 62.3% compared to 37.7% male subjects, with 78.7% of subjects being under 60 years of age. A study conducted in the United States of all CKD patients aged 18 years and above from 2017-2020 based on data from the National Health and Nutrition Examination Survey showed that CKD was more common in women than men (14.4% vs. 11.8%), ²⁴ in line with this study. Another study conducted in Austria by Lewandowski et al. ²⁵ using data from adult CKD patients in 6 hospitals in Austria from 1989-2008 showed that CKD was also more common in women than men (12.3% vs. 6.1%). Another finding by Vosters et al. ²⁶ studying multiethnic adult CKD sufferers (Dutch, Surinamese, African, Ghanaian, Turkish, and Moroccan) living in the Netherlands also found that women dominated the CKD population compared to men (57.8% vs. 42.2%) with a mean age of 45 years for men and 44 years for women. Majority of the patients initiate hemodialysis with an indication of uremia (60,6%), followed by pulmonary edema, oligo/anuria, dan lastly encephalopathy and refractory hyperkalemia (55,7%, 50,8%, 18,0% dan 9,8%) respectively.

Based on the assessment of the degree of pulmonary congestion, in this 61 study samples, the majority of samples showed moderate and severe pulmonary congestion (27.9% in each category) in pre-HD, while the majority of samples showed moderate pulmonary congestion (42.6%) in post-HD. This is in line with research done by Mallamaci et al., ²¹ where it is found that approximately 63% of patients had mild to moderate pulmonary congestion before initiation of hemodialysis, while the remaining 37% had mild to no pulmonary congestion. This finding is similar to the results obtained in this study, where the majority of CKD patients before initiation of hemodialysis experienced moderate to severe pulmonary congestion. A study in Kenya by Mwango et al. involving 120 patients with kidney failure revealed that nearly all were treated for uremia syndrome (98%), followed by hyperkalemia (55%) and fluid overload (49.2%). Similar findings were reported by Alemam et al. who examined 149 patients with acute kidney failure undergoing hemodialysis, discovering that 44% required hemodialysis due to uremia, followed by fluid overload at 30% and metabolic acidosis at 10%.

This study revealed a statistically significant reduction in the number of B-lines post-HD, decreasing from 23.4 to 16.9 (p < 0.05, 95% CI). This is in line with previous research by Curto, et al. ²⁷ who conducted a study on 27 kidney failure patients undergoing chronic hemodialysis and underwent chest ultrasound (4 sites and 8 sites methods), it was found that the number of pre-HD B-lines was significantly higher than the number of post-HD B-lines in both methods (R -0.67, p < 0.05). Similar findings were also reported in a study by Trezzi, et al., ²⁸ which examined 41 patients with kidney failure undergoing chronic hemodialysis and utilised chest ultrasound using the full-scanning method; revealing a significant decrease in the number of B-lines post-HD (from 24 ± 25 in pre-HD, to 9 ± 10 in post-HD, p < 0.001). A study conducted by Kaysi, et al. ¹¹ which examined the number of B-lines pre and post-HD first and second in a week in chronic HD patients, showed that in both the first and second HD, there was a significant reduction in the number of B-lines post-HD (16 ± 5.53 pre-HD and 15.3 ± 6.63 on the first post-HD session, dan 16.3 ± 5.27 pre-HD and 13.6 ± 5.83 on the second post-HD session; p < 0.001).

B-line imaging is a marker of pulmonary congestion. Detection of multiple and diffuse B-lines, especially when accompanied by a clinical presentation of shortness of breath, indicates pulmonary edema with high sensitivity. A significant reduction in the number of B-lines after hemodialysis indicates rapid clearance of pulmonary congestion following the elimination of excess fluid through hemodialysis. Noble et al. ²⁹ also reported that the number of B-lines also decreased midway to the end of a hemodialysis session. This demonstrates the effectiveness of lung ultrasound in evaluating the therapeutic effect of hemodialysis by observing B-lines. ²⁸

In this study, there was a significant improvement in the degree of pulmonary congestion pre- and post-HD, where the degree of pulmonary congestion (mild, moderate, severe, and no congestion) can be determined by looking at the number of B-lines (p < 0.05). This is in line with the study conducted by Annamalai et al. ³⁰ who conducted a study on 100 kidney failure patients undergoing chronic HD and underwent a full scanning thorax ultrasound method with a description of the number of B-lines: <5 (no congestion), 5-15 (mild), 16-30 (moderate), >30 (severe); it was found that there was an improvement in the number of B-lines pre-HD, an improvement in the status of pulmonary congestion, and a reduction in the diameter of the inferior vena cava (IVCD) post-HD (p < 0.001).

Another study by Mallamaci et al. ²¹ which assessed the effect of hemodialysis on the degree of pulmonary congestion in patients with kidney failure with chronic hemodialysis and initiation of hemodialysis as assessed by lung ultrasound, showed that there was a significant improvement in the degree of pulmonary congestion after hemodialysis sessions, where the percentage of patients with moderate to severe pulmonary congestion status in pre-HD decreased from 63% to 31% in post-HD (p < 0.001). ²²

Our study found that a significant positive correlation was found between initiation of hemodialysis and the decrease in the number of B-lines. Additionally, a significant positive correlation was found between initiation of hemodialysis and a decrease in the degree of pulmonary congestion. Our findings can serve as foundational data for subsequent research to evaluate the impact of initiation of hemodialysis on alleviating lung congestion in patients with kidney failure.

There was a correlation between initiation of hemodialysis and improvement in the degree of pulmonary congestion, as indicated by a reduction in the number of B-lines on post HD session. Further follow ups are required in the next couple sessions of hemodialysis to ensure the adequacy of the improvement of the lung congestion.

This study has been approved by the Research Ethics Committee of the Faculty of Medicine, Hasanuddin University through the publication of an ethical approval letter number 645/UN4.6.4.5.31/PP36/2025. The study adhered to the ethical principles, ensuring the protection of participants' rights and confidentiality.