Purpose or Case Report: Assessment of fluid overload in hemodialysis patients is usually based on a patient’s ideal weight which presents a challenge, especially in children due to normal growth and development. Noninvasive, validated sonographic fluid balance measurements could potentially guide fluid removal in children undergoing hemodialysis. We examine changes in IVC diameter and lung b-lines in children pre- and post- dialysis.
Methods & Materials: This prospective, HIPAA-complaint study measured the IVC diameters, collapsibility index as well as the presence and number of lung b-lines in 18 lung zones (i.e.; upper, mid and lower zones at midclavicular, anterior axillary and posterior axillary lines); on lung ultrasound in a cohort of children before and 1- hour after hemodialysis between January and September 2019. Images were reviewed by 2 pediatric radiologists blinded to clinically history and fluid status. Non-weighted descriptive analysis is presented.
Results: Six subjects (4 boys and 2 girls) median age 13.6 years (range: 3.4-17.7) completed 23 pre and post dialysis visits (41 ultrasound studies). The average maximum diameter of the IVC (Dmax) pre-dialysis was 1.56±0.6 cm and 1.51±0.6cm, for reader 1 and 2, vs. 1.29±0.5 cm and 1.31±0.6 cm post-dialysis, respectively. The average minimum diameter of the IVC (Dmin) pre-dialysis was 1.24±0.6 cm and 1.21±0.6 cm, for reader 1 and 2 vs. 1±0.5 cm and 1.09±0.6 cm post-dialysis, respectively. The IVC collapsibility index (IVCci) was 23.6±14.9 and 18.0±14.3 pre-dialysis- and 23.74±12.46 and 17.1±15.0 post-dialysis.
Average number of b-lines changed from pre- to post-dialysis as follows:
Right lung: 1.72±2.0 and 2.20±2.0 for reader 1 and 2, to 1.26±2.3 and 1.94±2.9, respectively.
Left lung: 2.26±3.5 and 2.63±4.4 for reader 1 and 2, to 1.30±3.2 and 1.70±3.2, respectively.
Conclusions: Ultrasound shows differences in IVC and b-line measurements after dialysis. However, there is significant interreader variability and overlap between pre- and post-dialysis values, hindering its potential use to guide clinical decisions in individual patients. Additional research with larger samples is needed to further define the potential role of ultrasound in the assessment of volume status in children on hemodialysis.