Pulse of Prudence: Navigating Isolated Lung Ultrasound in Patients Receiving Hemodialysis

We commend Chang, et al1Chang E.H. Tugman M.J. Assimon M.M. et al.Lung ultrasound, bioimpedance spectroscopy, and physical examination for volume assessment in hospitalized hemodialysis patients: a diagnostic test study.Kidney Med. 2024; 6100764https://doi.org/10.1016/j.xkme.2023.100764Abstract Full Text Full Text PDF Scopus (2) Google Scholar for exploring the role of lung ultrasound (LUS) in hospitalized hemodialysis patients. Given the rising interest in point-of-care ultrasonography (POCUS) among nephrologists, particularly isolated LUS, we wish to highlight some considerations for its cautious use. Although acknowledging the exclusion of patients with severe pulmonary fibrosis in this study, it is noteworthy that B-lines are also frequently seen in patients with recent infections and the prevalence of COVID-19 during the study period (2019-2021) adds complexity to the interpretation. Differentiating between cardiogenic and pneumogenic B-lines may require evaluating left ventricular filling pressures using Doppler techniques, which falls within the scope of appropriately trained nephrologists.2Koratala A. Olaoye O.A. Bhasin-Chhabra B. Kazory A. A blueprint for an integrated point-of-care ultrasound curriculum for nephrology trainees.Kidney360. 2021; 2: 1669-1676https://doi.org/10.34067/KID.0005082021Crossref PubMed Scopus (27) Google Scholar Furthermore, over-reliance on LUS may lead to oversight of right-sided cardiac dysfunction, prevalent in patients receiving dialysis and associated with its adverse outcomes, especially in those with brachial arteriovenous fistulas.3Paneni F. Gregori M. Ciavarella G.M. et al.Relation between right and left ventricular function in patients undergoing chronic dialysis.J Cardiovasc Med (Hagerstown). 2013; 14: 289-295https://doi.org/10.2459/JCM.0b013e32834eacf0Crossref PubMed Scopus (23) Google Scholar Inferior vena cava POCUS, and in some cases Doppler assessment of venous congestion aid in proper diagnosis.4Posada-Martinez E.L. Cox Z.L. Cano-Nieto M.M. et al.Changes in the inferior vena cava are more sensitive than venous pressure during fluid removal: a proof-of-concept study.J Card Fail. 2023; 29: 463-472https://doi.org/10.1016/j.cardfail.2022.09.012Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar,5Bajaj D. Koratala A. Utility of portal venous Doppler in the assessment of fluid status in end-stage kidney disease: think beyond IVC ultrasound.CEN Case Rep. 2022; 11: 285-287https://doi.org/10.1007/s13730-021-00661-3Crossref PubMed Scopus (8) Google Scholar Moreover, equating B-lines or a plethoric inferior vena cava with ultrafilterable fluid disregards conditions such as pulmonary hypertension, valvular disease, or increased afterload, requiring different therapeutic approaches. Postultrafiltration, patients with left ventricular hypertrophy may exhibit systolic anterior motion of the mitral valve leaflet and consequent functional mitral regurgitation, causing B-lines without fluid overload, underscoring the need for a thorough cardiac POCUS, including a left ventricular outflow evaluation. Furthermore, caution is advised when comparing LUS with bioimpedance (extracellular water/total body water) and physical examination findings (pedal edema), because they may not necessarily convey identical information. Future research must explore a multiorgan hemodynamic POCUS approach in these patients (Fig 1). None. The authors declare that they have no relevant financial interests. Received December 8, 2023. Accepted January 29, 2024 after editorial review by the Editor-in-Chief. Lung Ultrasound, Bioimpedance Spectroscopy, and Physical Examination for Volume Assessment in Hospitalized Hemodialysis Patients: A Diagnostic Test StudyKidney MedicineVol. 6Issue 2PreviewAccurately estimating extracellular volume status and establishing a euvolemic target weight are critical to caring for people treated with dialysis. However, physical examination findings of lung crackles and peripheral edema are often unreliable markers of volume status.1 Lung ultrasound is a low-risk, relatively inexpensive tool that may improve volume status assessment as well as ambulatory blood pressure, lung congestion, and cardiac indices in the outpatient dialysis setting.2-5 Full-Text PDF Open AccessIn Reply to "Pulse of Prudence: Navigating Isolated Lung Ultrasound in Hemodialysis Patients"Kidney MedicineVol. 6Issue 8PreviewWe thank Bhasin-Chhabra and Koratala1 for their interest in our study.2 They underscore the limitations of lung ultrasound for differentiating between cardiogenic and pneumogenic B-lines and identifying excess fluid that is accessible to ultrafiltration with dialysis, especially in the presence of infection, right-sided heart failure, and valvular dysfunction.3,4 Indeed, these limitations of the interpretation of lung ultrasound led to our decision to study the utility of lung ultrasound among patients with dialysis-dependent chronic kidney failure in the hospital, a setting where infection and lung and/or cardiac pathology are common.