Volume assessment in hemodialysis: A comparison of present methods in clinical practice with sonographic lung comets

Abstract

Dry weight assessment in dialysis patients remains a challenging endeavor owing to the limitations of the available methods for volume assessment. Lung ultrasound is emerging as an invaluable tool to assist in the appropriate assessment and assignment of dry weight. The objectives of this study are (1) to determine the reliability of clinical signs and symptoms for volume assessment, (2) to compare lung ultrasound with High Resolution Computed Tomography (HRCT) chest-A noninvasive gold standard tool for detecting pulmonary congestion and with inferior vena cava diameter (IVCD) – another time-tested volume assessment method, and (3) to analyze if lung ultrasound could detect dialysis induced fluid status variations. The cross-sectional study involves 50 patients on maintenance hemodialysis. Lung ultrasound for B line estimation and ultrasonographic measurement of IVCD performed before and after hemodialysis by a nephrologist trained in ultrasonography. Limited HRCT was obtained just before hemodialysis. Edema, crackles, and dyspnea had a poor sensitivity of 37.9%, 11.5%, and 52.6%, respectively, to detect clinically significant pulmonary congestion by lung ultrasound. A highly significant correlation was obtained between B-line score and HRCT signs of pulmonary congestion ( P < 0.001) before dialysis. B lines showed statistically significant reduction with dialysis. The absolute reduction of B lines showed significant correlation with ultrafiltration volume and weight loss. Bedside lung ultrasound appears a sensitive tool for evaluating real-time changes in extravascular lung water and would serve to optimize volume status in dialysis patients.

The use of lung ultrasound in evaluation of extravascular lung water in hemodialysis patients: Systematic review and meta‐analysis

“…11 Lung congestion, as determined by the count of sonographic B-lines, can be classified into categories of severity: mild (<14 comets), moderate (14-30 comets), or severe (>30 comets). 6,22,48 In our review, seven studies indicated mild congestion, one showed moderate congestion, and three demonstrated severe lung congestion pre-hemodialysis. It's noteworthy that traditional clinical signs, such as lower limb edema and auscultatory crackles, show lower sensitivity and accuracy.…”

“…Sonographic B‐lines exceeding five serve as an early indicator of pulmonary congestion, frequently preceding the onset of apparent pulmonary edema by approximately 2 weeks 11 . Lung congestion, as determined by the count of sonographic B‐lines, can be classified into categories of severity: mild (<14 comets), moderate (14–30 comets), or severe (>30 comets) 6,22,48 . In our review, seven studies indicated mild congestion, one showed moderate congestion, and three demonstrated severe lung congestion pre‐hemodialysis.…”

“…These comprised 14 prospective cohort studies, 17 cross‐sectional studies, and two prospective observational studies (Figure 1). The meta‐analysis incorporated 13 studies 6,7,18–28 of the included 33 studies, while the other 20 studies, lacking sufficient numerical data, were included for qualitative analysis as part of the systematic review 9,29–47 …”

“…13,[17][18][19] Furthermore, other investigations reported a correlation between recurrent positive lung ultrasound and the rate of cardiovascular events, including hospitalization. 20,21 Additionally, positive associations were found between lung comet numbers and pre-dialysis diastolic blood pressure, 22 as well as between B-lines and NT-pro-BNP in hemodialysis patients 23 (Table 2).…”

Volume Status Assessment by Lung Ultrasound in End-Stage Kidney Disease: A Systematic Review

“…From the 46 articles selected for full-text review, we excluded another 20 articles: 5 review articles (all studies mentioned in these manuscripts had already been included in our review), 1 editorial, 1 meta-analysis, 6 articles that did not study the exposure of interest, 4 articles that did not present the outcome(s) of interest, 2 articles were subanalyses of an included randomized controlled study. A total of 28 studies were included in our systematic review: 25 observational studies, 4 , 26 - 49 and 3 RCTs as shown in Figure 1 . 18 , 19 , 50 The randomized controlled studies did not address the same endpoints as the observational studies and are separately presented in a different section of the results.…”