Abstract
Background and Aims
The aim of study was to compare the lung ultrasound (LUS) and bioimpedance analysis (BIA) as methods to assess the hydration (fluid) status in maintenance hemodialysis (MHD) patients.
Method
The comparative analysis was performed in 87 MHD patients aged 24 to 82 years (43 women, and 44 men). Patients with cardiac pacemakers and permanent catheters as vascular access were excluded from the study. Extravascular lung water (EVLW) in MHD patients was assessed simultaneously by LUS (Acuson X150 ultrasound system with a CH5-2 curvilinear transducer, Siemens) and by the bioimpedance spectroscopy (BIS) (Bodystat Multiscan 5000) with frequency range of 5-1000K Hz. Both LUS and BIS were performed before and 30 minutes after the hemodialysis (HD) session in the second and third sessions of the week. Ultrasonic measurements were performed by summing LUS comets or B-lines along four anatomical lines (parasternal, mid-clavicular, anterior, middle, and posterior axillary lines) from II to V intercostal spaces on the right and from the II to IV intercostal spaces on the left. The quantitative assessment of B-lines (B-lines score, BLS) was performed according to Picano E. et al. [2006]: normohydration – zero degree (<4 B lines) with the absence of EVLW, overhydration (OH) – 1st degree (5-14 BLS), 2nd degree OH (15-30 BLS), and 3d degree OH – >30 BLS with an insignificant, moderate and severe amount of EVLW, respectively. The body hydration status assessment technique by BIS was based on the overhydration (OH) index, the total body water volume, extra- and intracellular water, and the body composition.
Patient's fluid status classified as normohydration (1.0-1.0 L), moderate OH (>1.0-<2.5 L), and severeOH (>2.5 L), and dehydration (<1.0 L) [Henry C. Lukaski et al., 2019]. The LUS do not allow assessing the state of dehydration, therefore, the normohydration by LUS was the sum of normo- and dehydration by BIS. We used SPSS Statistics 21.0 software for statistical processing of the data. To assess the correlation between BLS and OH indicators, we used Spearman's rank correlation coefficient. The statistical significance level was assumed to be 0.05.
Results
Data of the body fluid status using LUS and BIS before and after HD-session fully coincided in 33 of 87 MHD patients, partially coincided in 20 patients before and in 25 patients after HD-session. LUS and BIS didn’t coincide completely in only 9 patients. Statistically significant correlation was revealed between BLS and OH before (Rs=0.336; p<0.01), and after (Rs=0,317, p<0,01) HD session. A positive correlation between BLS and OH data was revealed in 53 patients, whose results were almost identical before (Rs=0,488, p<0.01), and in 58 patients after (Rs=0,658, p<0.01) HD session.
Conclusion
BIS remains the gold standard for the assessment of over-, normo- and dehydration in MHD patients. LUS is a simple and adequate technique for assessing the hydration status in MHD patients, and it is comparable to BIS in assessing over-, as well as normohydration. However, the LUS doesn’t allow diagnosing the body dehydration.
A Pilot Study of Wet Lung Using Lung Ultrasound Surface Wave Elastography in an Ex Vivo Swine Lung Model