In a recent original investigation by Marino et al in this month’s issue of Kidney International the authors show that lung ultrasound has clinical utility beyond the outpatient dialysis unit. Prior work by this Italian group has shown that the quantitation of B lines on lung ultrasound correlates with extravascular lung water and mortality in patient’s with ESRD on HD. In the present study the authors quantified B lines in 42 non-dyspneic patients with active nephrotic syndrome and compared their findings to healthy controls and to ESKD patients. For each of the three groups lung ultrasound was performed 5 minutes after lying supine, 60 minutes after lying supine, and then after standing. They found that the number of B lines among patients with active nephrotic syndrome was similar to the number of B lines in chronic dialysis patients. Furthermore they found that B lines in patients with nephrotic syndrome accumulated while lying supine for 60 minutes and diminished after standing up. Further analysis demonstrated a strong indirect relationship between serum albumin and number of B lines in the nephrotic syndrome cohort. In other words, a lower albumin was predictive of greater extravascular lung water. Finally, the authors evaluated a subset of 11 patients that experienced disease remission. Each of these patients had significantly fewer B lines compared to ultrasound results during active disease. Quantitation of B lines by lung ultrasound can be learned in a single 3 to 4 hour training session and the procedure takes about four to six minutes to perform. As ultrasound machines become smaller, cheaper, and more available, lung ultrasound will likely become a critical component in the assessment of volume status by nephrologists.
Post byDaniel Ross, MD
Hofstra Northwell School of Medicine