Assessment and management of fluid overload in children on dialysis

Assessment of volume status of pediatric hemodialysis patients

BACKGROUND

Accurate volume status assessment and dry weight achievement are the most challenging goals for a nephrologist. We aimed to evaluate the role of ultrasonographic parameters including lung ultrasound and inferior vena cava (IVC) measurements as practical methods of volume status assessment in children on hemodialysis by comparing them with established techniques, such as clinical evaluation and bioimpedance spectroscopy.

METHODS

A prospective cross-sectional study compared pre- and post-dialysis volume status using bioimpedance spectroscopy (BIS) parameters and clinical data with ultrasonographic lung B-lines and IVC parameters in children on regular hemodialysis.

RESULTS

A total 60 children (mean age 9.4 ± 2.8 years) were enrolled. Twenty patients (33.3%) were clinically overloaded to varying degrees (17 patients had mild to moderate signs of fluid overload and 3 patients had moderate to severe signs of fluid overload). All other patients (66.7%) were clinically euvolemic. Sonographic parameters were significantly lower post-dialysis than pre-dialysis, including lung B-line count and IVC diameter. IVC collapsibility index mean was significantly higher post-dialysis than pre-dialysis. There was a significant correlation between the lung B-line count, IVC parameters, and BIS-measured overhydration both before and after hemodialysis. Nine patients had ≥ 8 B-lines post-dialysis, only three of them were hypertensive.

CONCLUSIONS

Clinical criteria alone are not specific for determining accurate fluid status in pediatric hemodialysis patients. Lung B-line score, IVC parameters, and BIS may be complementary to each other and to clinical data. Lung B-lines outperform IVC measurements and BIS in subclinical volume overload detection in pediatric hemodialysis patients.

Effect of peritoneal dialysate on bioelectrical impedance analysis variability in pediatric patients receiving peritoneal dialysis

BACKGROUND

Previous adult studies have yielded conflicting results regarding whether the presence (D +) or absence (D-) of peritoneal dialysate affects the accuracy of bioelectrical impedance analysis (BIA) measurements. The aim of this study was to investigate whether the accuracy of BIA data varies between D + and D- measurements in children.

METHODS

This cross-sectional study recruited chronic kidney disease stage 5 patients aged 3 to 18 years who received peritoneal dialysis. Body composition was assessed by multifrequency BIA, and values were compared between D + and D- measurements using the intraclass correlation coefficient (ICC).

RESULTS

Fifty paired BIA measurements were collected from 18 patients with a mean age of 13.6 ± 4.1 years and a mean dialysate fill volume of 1,006 ± 239.7 ml/m2. Sixteen out of 17 BIA parameters (94.1%) exhibited excellent correlations between D + and D- measurements (ICC values = 0.954, 0.998). There was a trend of increased fluid status, including extracellular water, edema index, and overhydration, in D + measurements, with mean differences (95% CIs) of 0.5 (0.4, 0.6) L, 0.002 (0.001, 0.002), and 0.1 (0.1, 0.2) L, respectively. Soft lean mass and fat-free mass were higher in D + measurements, with mean differences (95% CIs) of 1.4 (1.2, 1.6), and 1.6 (1.4, 1.8) kg, respectively. In addition, patients older than 10 years had a stronger correlation between D + and D- measurements than younger patients.

CONCLUSIONS

A total of 94.1% of BIA parameters exhibited excellent correlations between D + and D- measurements, especially patients older than 10 years. We recommend that BIA measurements be collected from children regardless of the presence of peritoneal dialysate.

Nutrition in Critically Ill Children with AKI on Continuous RRT: Consensus Recommendations

BACKGROUND

Nutrition plays a vital role in the outcome of critically ill children, particularly those with AKI. Currently, there are no established guidelines for children with AKI treated with continuous RRT (CRRT). A thorough understanding of the metabolic changes and nutritional challenges in AKI and CRRT is required. Our objective was to create clinical practice points for nutritional assessment and management in critically ill children with AKI receiving CRRT.

METHODS

PubMed, MEDLINE, Cochrane, and Embase databases were searched for articles related to the topic. Expertise of the authors and a consensus of the workgroup were additional sources of data in the article. Available articles on nutrition therapy in pediatric patients receiving CRRT through January 2023.

RESULTS

On the basis of the literature review, the current evidence base was examined by a panel of experts in pediatric nephrology and nutrition. The panel used the literature review as well as their expertise to formulate clinical practice points. The modified Delphi method was used to identify and refine clinical practice points.

CONCLUSIONS

Forty-four clinical practice points are provided on nutrition assessment, determining energy needs, and nutrient intake in children with AKI and on CRRT on the basis of the existing literature and expert opinions of a multidisciplinary panel.

Developing a trigger tool to monitor adverse events during haemodialysis in children: a pilot project

BACKGROUND

We developed a paediatric haemodialysis trigger tool (pHTT) for application per haemodialysis (HD) session in children receiving intermittent in-centre HD and systematically monitored adverse events.

METHODS

Single-centre quality improvement study performed over two 8-week cycles. Data collected prospectively using a 'per-dialysis session' pHTT tool including 54 triggers across six domains, adapted from a recently described haemodialysis trigger tool (HTT) for adults. Each trigger was evaluated for level of harm following assessment by two authors. Following a period of training, HD nurses completed the HTT at the end of each dialysis session.

RESULTS

There were 241 triggers over 182 dialysis sessions, with 139 triggers in 91 HD sessions for 15 children, age range 28-205 months, over an 8-week period (first cycle) and 102 triggers in 91 HD sessions for 13 children, age range 28-205 months, over a further 8-week period (second cycle). After interventions informed by the pHTT, the harm rate per session was significantly reduced from 1.03 (94/91) to 0.32 (29/91), P < 0.001. There was a significant difference between the distribution of triggers by harm category (P < 0.001) and between the proportion of triggers across the various domains of the pHTT (P = 0.004) between the two cycles. No triggers were evaluated as causing permanent harm.

CONCLUSIONS

This pilot study demonstrates potential benefits of a bedside tool to monitor adverse events during haemodialysis in children. Thus, following interventions informed by the pHTT, the harm rate per session was significantly reduced. Under standard patient safety systems, the vast majority of triggers identified by the pHTT would remain unreported and perhaps lead to missed opportunities to improve patient safety. We propose the use of a paediatric HTT as part of standard care by centres providing HD to children in the future. A higher resolution version of the Graphical abstract is available as Supplementary information.

Assessment of fluid status in neonatal dialysis: the need for new tools

BACKGROUND

Assessment of fluid status in neonatal dialysis has largely focused on traditional tools including clinical assessment, serial weights, and blood pressure (BP) measurements. However, in infants on kidney replacement therapy, the assessment of fluid overload is problematic due to errors in weight assessment, subtlety of physical exam findings, and inaccuracy of non-invasive BP measurements. In this presentation of a neonate with bilateral renal agenesis requiring kidney replacement therapy, the treating team assessed a number of variables in determining the ultrafiltration prescription for dialysis across 2 modalities (hemodialysis and continuous kidney replacement therapy).

COMPLICATIONS

Fluid overload, cardiomegaly, and worsened respiratory status occurred when attempting to assess the neonate's fluid status by traditional markers (weights, blood pressures, physical exam findings). B-type natriuretic peptide (BNP) was obtained and was noted to correlate with the degree of fluid overload.

KEY MANAGEMENT POINTS

Compared to traditional tools for assessment of fluid status in pediatric dialysis, BNP assisted the medical team in optimizing the volume status of the subject and determining optimal daily ultrafiltration goals. Due to the rapid release in response to myocardial stretch and the lack of kidney clearance of the peptide, BNP may represent an objective, timely, and reliable index of volume status in the pediatric dialysis patient.

Fluid management in hospitalized pediatric patients

The proper use of intravenous fluids has likely been responsible for saving more lives than any other group of substances. Proper use includes prescribing an appropriate electrolyte and carbohydrate solution, at a calculated rate or volume, for the right child, at the right time. Forming intravenous fluid plans for hospitalized children requires an understanding of water and electrolyte physiology in healthy children and how different pathology deviates from the norm. This review highlights fluid management in several disease types, including liver disease, diabetic ketoacidosis, syndrome of inappropriate antidiuretic hormone, diabetes insipidus, kidney disease, and intestinal failure as well as in those with nonphysiologic fluid losses. For each disease, the review discusses specific considerations, evaluations, and management strategies to consider when customizing intravenous fluid plans. Ultimately, all hospitalized children should receive an individualized fluid plan with recurrent evaluations and fluid modifications to provide optimal care.

Nutritional status and volume control in adolescents on chronic hemodialysis

BACKGROUND

Pediatric patients on maintenance hemodialysis (HD) are at risk of both malnutrition and fluid overload. This pilot study aimed to assess correlates of normalized protein catabolic rate (nPCR) in adolescents on chronic HD, in particular fluid status markers.

METHODS

All patients aged 10-18 years on chronic HD in our center between 2017 and 2019 were enrolled. For each patient, mean nPCR was calculated and correlations with the following parameters investigated: dry body weight change in subsequent 3 months in kg (∆BW) and percentage of BW (∆BW%), change in body mass index (∆BMI), preHD systolic and diastolic blood pressure (SBP, DBP), residual urine output, biochemistry, and blood volume monitoring-derived first hour refill index (RI), calculated as ratio between ultrafiltration rate and reduction in relative blood volume in first hour of dialysis.

RESULTS

Seventy-nine nPCR determinations were collected in 23 patients, median age 14.8 years. nPCR significantly correlated with ∆BW, ∆BW%, ∆BMI, spKT/V, and preHD serum creatinine, and negatively correlated with age, DBP SDS (r=-0.466, p=0.025) and RI (r=-0.435, p=0.043). RI was significantly higher in patients with nPCR <1 than those with nPCR above this threshold: 3.2 (1.9-4.7) vs. 1.4 (0.7-1.8) ml/kg/h/% (p=0.021). At multivariable analysis, nPCR remained positively correlated with creatinine and spKt/V, and inversely correlated with RI.

CONCLUSIONS

nPCR is a significant predictor of weight change in adolescents on maintenance HD, and seems associated with creatinine and dialysis adequacy. Inverse correlation with RI suggests possible associations between malnutrition and fluid overload, but larger prospective studies are needed to confirm this. A higher resolution version of the Graphical abstract is available as Supplementary information.

Nutritional Assessment and Management in Paediatric Chronic Kidney Disease

Nutrition in paediatrics has always been one of the most important factors for optimal growth. Children with chronic kidney disease (CKD) need special consideration for better long-term outcomes, including nutritional status, optimal height, and cognitive function. Nonetheless, there are many obstacles to overcome to attain optimal linear growth and nutritional status in children with CKD. This review highlights the need for tools to assess the growth parameters in CKD. In addition, recommendations for dietary intake play a major role in controlling electrolyte disturbances in patients with CKD. For example, it is still unclear whether it is better to restrict phosphate sources in inorganic, organic, or food additives. The review also summarises different factors such as fluid intake, route of feeding, and essential nutrients that require particular attention in paediatric patients with CKD. In summary, a multidisciplinary team is needed to devise individual nutritional plans to achieve the best outcome and improve the quality of life of patients.

Bedside sonographic assessments for predicting predialysis fluid overload in children with end-stage kidney disease

Although the number of studies evaluating methods to predict fluid overload is increasing, the assessment of fluid status in children on dialysis is still fraught with inaccuracies. We aimed to evaluate the predictive capability of lung ultrasounds and the inferior vena cava collapsibility index (cIVC) in predialysis overhydration in children with end-stage kidney disease. Ten children with end-stage kidney disease who were on an intermittent hemodialysis program were included. The hydration status of the patients was clinically evaluated. Moreover, 30 predialysis and 30 postdialysis lung ultrasound, cIVC, and bioimpedance spectroscopy (BIS) measurements were performed. The median age of the participants was 14 (IQR, 13-15) years, and two (20%) were male. There was a strong positive correlation between the predialysis total number of B-lines and predialysis fluid overload (r=0.764, p<0.001). Additionally, there was a moderate negative correlation between predialysis cIVC and predialysis fluid overload (r=-0.599, p=0.002). Although the moderate correlation was determined between the postdialysis fluid overload and total number of B-lines, no correlation was determined using cIVC. Receiver operating characteristic curves demonstrated that the total number of B-lines and cIVC could successfully predict the predialysis fluid overload (relative hydration >7% derived from the BIS; AUROC 0.82 and 0.80, respectively). When both evaluations were combined, if either the total number of B-lines or the cIVC was outside the corresponding cutoff range (>10.5 and ≤23.5, respectively), it was detected in 16 out of 17 sessions (sensitivity 94%). If either one was outside the corresponding cutoff range (total number of B-lines >10.5 and cIVC ≤18.2), the severe predialysis fluid overload was predicted successfully in all eight (100%) sessions. Conclusion: Randomized controlled studies are needed to prove the reliability of the combined use of lung ultrasounds and cIVC in the assessment of predialysis fluid overload. What is Known: • The association of chronic fluid overload with increased morbidity and mortality raises the need for optimal determination of fluid overload in pediatric patients who are dialysis-dependent at a young age. • The linear correlation between the total number of B-lines on lung ultrasound images and fluid overload by weight has been shown. What is New: • This study evaluates the lung ultrasound and inferior vena cava collapsibility index combined in predicting fluid overload in dialytic children. • If either the total number of B-lines or the cIVC was outside the corresponding cutoff range (>10.5 and cIVC ≤18.2, respectively), the severe predialysis fluid overload was predicted successfully in all eight (100%) sessions.

Monitoring dialysis adequacy: history and current practice

Dialysis adequacy for pediatric patients has largely followed the trends in adult dialysis by judging the success or adequacy of peritoneal or hemodialysis with urea kinetic modeling. While this provides a starting point to establish a dose of dialysis, it is clear that urea is only part of the picture. Many clinical parameters and interventions now have been identified that are just as impactful on mortality and morbidly as urea clearance. As such, our concept of adequacy is evolving to include non-urea parameters and assessing the impact that following an "adequate therapy" has on patient lives. As we move to a new era, we consider the impact these therapies have on patients and how it affects the quality of their lives; we must take these factors into consideration to achieve a therapy that is not just adequate, but livable.

Lung ultrasound methods for assessing fluid volume change and monitoring dry weight in pediatric hemodialysis patients

BACKGROUND

The value of lung ultrasound in adult hemodialysis has been confirmed. The determination of dry weight in children remains challenging. This study explores the usefulness of lung ultrasound in assessing fluid volume change and the possibility of pulmonary ultrasound as a method to monitor dry weight in pediatric dialysis patients.

METHODS

This was a prospective observational study. We compared the predialysis and postdialysis B-line scores of the dry-weight group and non-dry-weight group. Changes in body weight and B-line scores were recorded during the dialytic period and interdialytic period, and the correlation was analyzed. Lung ultrasound was performed after the dialysis session every Friday, and B-line score < 10 was considered to indicate that there was no volume overload; the weight was recorded as the target weight.

RESULTS

Fourteen patients were included. A total of 78 ultrasound assessments were performed: 30 in the dry-weight group and 48 in the non-dry-weight group. The B-line scores decreased after dialysis in all patients (p < 0.001). Thirty-three assessments were performed in the interdialytic period, and 40 assessments in the dialytic period were performed within 1 week. Linear regression showed that changes in B-line number were directly and positively correlated with interdialytic weight gain (r = 0.517, p = 0.002) and dialytic weight loss (r = 0.558, p < 0.001). The weight of the children increased gradually without volume overload in two patients during follow-up.

CONCLUSION

Lung ultrasound can assess the fluid volume change of pediatric dialysis patients in real time. Lung ultrasound could be a valuable method for monitoring dry weight in pediatric dialysis patients.

Clinical Relevance of Fluid Volume Status Assessment by Bioimpedance Spectroscopy in Children Receiving Maintenance Hemodialysis or Peritoneal Dialysis

Bioimpedance spectroscopy (BIS) is a noninvasive method used to evaluate body fluid volume status in dialysis patients, but reports on its effectiveness in pediatrics are scarce. We investigated the correlation between BIS and clinical characteristics and identified the changes in patients whose dialysis prescription was modified based on BIS. The medical records of children on maintenance dialysis who had undergone BIS between 2017 and 2019 were reviewed. Of the 49 patients, 14 were overhydrated, based on the >15% proportion of overhydration relative to extracellular water (OH/ECW) measured by BIS. Intake of ≥two antihypertensive medications was noted in the majority (85.7%) of children with fluid overload and only in 48.6% of those without fluid overload (p = 0.017). Elevated blood pressure despite medication use was significantly more common in patients with fluid overload than in those without fluid overload (78.6% vs. 45.7%, p = 0.037). Of the 14 overhydrated children, 13 (92.9%) had significant changes in body weight, OH/ECW, the number of antihypertensive drugs, left ventricular end-diastolic diameter, and cardiothoracic ratio after the change in dialysis prescription. BIS is a useful and noninvasive method to assess fluid status in dialysis children. Long-term follow-up and correlation with a more objective clinical indicator of fluid overload is necessary to verify the clinical effectiveness of BIS.

Tracking hydration status changes by bioimpedance spectroscopy in children on peritoneal dialysis

BACKGROUND

This 6-month prospective longitudinal study investigates the association between hydration status changes using bioimpedance spectroscopy (BIS) and systolic blood pressure (SBP), pulse pressure (PP), and serum albumin (sAlb) changes in children on peritoneal dialysis (PD).

METHODS

Thirteen patients (median age: 12.58 years) were enrolled. Normal hydration, moderate hydration, severe overhydration, and dehydration were defined as -7% ≤ relative overhydration (Re-OH) < +7%, +7% ≤ Re-OH < +15%, Re-OH ≥ +15%, and Re-OH < -7%, respectively. Automated office blood pressure z-score, sAlb, and weight z-score were recorded.

RESULTS

Fifty-two Re-OH measurements were recorded: three in five, four in five, five in two, and seven in one patient, respectively. SBP was higher and sAlb lower in cases with severe overhydration (9 readings) (p < 0.001, p < 0.001), but distribution of these parameters did not differ between normal hydration/dehydration (28 readings) and moderate overhydration (15 readings) cases. In patients with hydration status change, SBP and PP were higher while sAlb lower in cases with higher hydration status level (p = 0.026, p = 0.05, and p = 0.109, respectively). In all patients, visit-to-visit SBP, PP, and sAlb changes were correlated to Re-OH changes (rs = 0.693, p < 0.001; rs = 0.643, p < 0.001; rs = -0.444, p = 0.008, respectively) but not to weight changes (rs = 0.052, p = 0.754; rs = 0.034, p = 0.838; rs = -0.156, p = 0.378, respectively). Visit-to-visit Re-OH changes, which were >+4% or <-4%, were linearly correlated to SBP (r = 0.858, p < 0.001), PP (r = 0.757, p < 0.001), and sAlb (r = -0.699, p = 0.002) changes.

CONCLUSION

In children on PD, longitudinal Re-OH changes are superior to weight changes in assessing volume-dependent variations of SBP, PP, and sAlb. Routine BIS application, rather than single BIS measurements, seems useful in the intra-patient monitoring of hydration status.

Effect of hemodialysis on impedance cardiography (electrical velocimetry) parameters in children

BACKGROUND

Pediatric hemodialysis (HD) patients have a high incidence of cardiovascular morbidity and mortality. The study aim was to investigate whether impedance cardiography (electrical velocimetry, EV) is suitable as a hemodynamic trend monitoring tool in pediatric patients during HD.

METHODS

Measurements by EV were obtained before, during, and after HD in a prospective single-center pediatric observational study. In total, 54 dialysis cycles in four different pediatric patients with end-stage kidney disease on chronic HD were included. EV parameters analyzed were heart rate (HR), stroke volume (SV), stroke volume index (SI), cardiac output (CO), cardiac index (CI), thoracic fluid content (TFC), index of contractility (ICON), stroke volume variation (SVV), variation of ICON (VIC), R-R interval (TRR), pre-ejection period (PEP), left ventricular ejection time (LVET), and systolic time ration (STR). Systemic vascular resistance index (SVRI) was calculated.

RESULTS

EV did measure significant changes in cardiovascular parameters associated with HD. The following parameters increased after HD: HR (9%), SVV (19%), VIC (33%), PEP (8%), and STR (18%). A decrease after HD was measured in SV (18%), SI (18%), CO (10%), CI (10%), TFC (10%), ICON (7%), TRR (7%), LVET (8%), and LVET (8%). SVRI was not affected by HD. The changes were correlated to ultrafiltration. HD cycles without fluid withdrawal also altered cardiovascular parameters.

CONCLUSIONS

Pediatric HD with and without fluid withdrawal changes hemodynamic EV monitoring parameters. Possibly EV may be useful to optimize HD management in pediatric patients.

Cardiovascular risk factors in children on dialysis: an update

Cardiovascular disease (CVD) is a life-limiting comorbidity in patients with chronic kidney disease (CKD). In childhood, imaging studies have demonstrated early phenotypic characteristics including increases in left ventricular mass, carotid artery intima-media thickness, and pulse wave velocity, which occur even in young children with early stages of CKD. Vascular calcifications are the signature of an advanced phenotype and are mainly found in adolescents and young adults treated with dialysis. Association studies have provided valuable information regarding the significance of a multitude of risk factors in promoting CVD in children with CKD by using intermediate endpoints of measurements of surrogate parameters of CVD. Dialysis aggravates pre-existing risk factors and accelerates the progression of CVD with additional dialysis-related risk factors. Coronary artery calcifications in children and young adults with CKD accumulate in a time-dependent manner on dialysis. Identification of risk factors has led to improved understanding of principal mechanisms of CKD-induced damage to the cardiovascular system. Treatment strategies include assessment and monitoring of individual risk factor load, optimization of treatment of modifiable risk factors, and intensified hemodialysis if early transplantation is not possible.

Beyond playing games: nephrologist vs machine in pediatric dialysis prescribing

In a recent article in Pediatric Nephrology, Olivier Niel and colleagues applied an artificial intelligence algorithm to a clinical problem that continues to challenge experienced pediatric nephrologists: optimizing the target weight of children on dialysis. They compared blood pressure, antihypertensive medication and intradialytic symptoms in children whose target weight was prescribed firstly by a nephrologist, then subsequently using a machine learning algorithm. Improvements in all outcome measures are reported. Their innovative approach to tackling this important clinical problem appears promising. In this editorial, we discuss the strengths and weaknesses of their study and consider to what extent machine learning strategies are suited to optimizing pediatric dialysis outcomes.