Evaluating methods for improving ultrafiltration in pediatric hemodialysis

Intradialytic Hypotension and Mortality in Adolescents and Young Adults With Kidney Failure Receiving Maintenance Hemodialysis

Rationale & Objective

Intradialytic hypotension (IDH) is associated with mortality in adults with kidney failure requiring hemodialysis (HD); however, large-scale pediatric studies are lacking. Moreover, there is no evidence-based consensus definition of IDH in pediatric literature. We aimed to examine the association of commonly used definitions of IDH with mortality in adolescents and young adults.

Study Design

This was a retrospective observational cohort study.

Setting & Participants

In total, 1,199 adolescents and young adults (N = 320, aged 10-18 years and N = 879, aged 19-21 years) who initiated HD in a large dialysis organization were included.

Exposures

This study used different definitions of IDH.

Outcome

The study outcome was 2-year all-cause mortality.

Analytical Approach

Several definitions of IDH were selected a priori based on a literature review. Patients were classified as having IDH if it was present in at least 30% of HD treatments during the first 90 days after dialysis initiation. Cox proportional hazards regression was used to test whether IDH associated with 2-year all-cause mortality.

Results

Over a 2-year follow-up period, 54 (4.5%) patients died. Dependent on its definition, IDH was present in 2.9%-61.1% of patients. After the multivariable adjustment for sociodemographic and clinical characteristics, we found no association of IDH with mortality. Results were consistent across subgroups stratified by age (aged <18 and 19-21 years) and predialysis systolic blood pressure (<120, 120-150, and >150 mm Hg). We also examined IDH as occurring in <5%, 5%-29%, 30%-50%, and >50% of baseline treatments, and did not find a dose-response association with mortality (P > 0.05).

Limitations

Owing to low event rates, our current sample size may have been too small to detect a difference in mortality.

Conclusions

Our study found that IDH was not associated with mortality in adolescents and young adults.

Advanced thermal sensing techniques for characterizing the physical properties of skin

Measurements of the thermal properties of the skin can serve as the basis for a noninvasive, quantitative characterization of dermatological health and physiological status. Applications range from the detection of subtle spatiotemporal changes in skin temperature associated with thermoregulatory processes, to the evaluation of depth-dependent compositional properties and hydration levels, to the assessment of various features of microvascular/macrovascular blood flow. Examples of recent advances for performing such measurements include thin, skin-interfaced systems that enable continuous, real-time monitoring of the intrinsic thermal properties of the skin beyond its superficial layers, with a path to reliable, inexpensive instruments that offer potential for widespread use as diagnostic tools in clinical settings or in the home. This paper reviews the foundational aspects of the latest thermal sensing techniques with applicability to the skin, summarizes the various devices that exploit these concepts, and provides an overview of specific areas of application in the context of skin health. A concluding section presents an outlook on the challenges and prospects for research in this field.

Evolution and change in paradigm of hemodialysis in children: a systematic review

BACKGROUND

There are similarities in hemodialysis (HD) between adults and children and also unique pediatric aspects. In this systematic review, we evaluated the existing HD literature, including vascular access, indications, parameters, and outcomes as a reflection on real-life HD practices.

METHODS

Medline, Embase, CINAHL, Web of Science, and Cochrane Library were systematically searched for literature on HD in children (1-20 years). Two reviewers independently assessed the literature and data on indications; vascular access, outcomes, and specific parameters for HD were extracted.

RESULTS

Fifty-four studies (8751 patients) were included in this review. Studies were stratified into age groups 1-5, 6-12, and 13-20 years based on median/mean age reported in the study, as well as era of publication (1990-2000, 2001-2010, and 2011-2019). Across all age groups, both arteriovenous fistulas and central venous catheters were utilized for vascular access. Congenital abnormalities and glomerulopathy were the most common HD indications. HD parameters including HD session duration, dialysate and blood flow rates, urea reduction ratio, and ultrafiltration were characterized for each age group, as well as common complications including catheter dysfunction and intradialytic hypotension. Median mortality rates were 23.3% (3.3), 7.6% (14.5), and 2.0% (3.0) in ages 1-5, 6-12, and 13-20 years, respectively. Median transplantation rates were 41.6% (38.3), 52.0% (32.0), and 21% (25.6) in ages 1-5, 6-12, and 13-20, respectively.

CONCLUSION

This comprehensive systematic review summarizes available literature on HD in children and young adults, including best vascular access, indications, technical aspects, and outcomes, and reflects on HD practices over the last three decades.

Pediatric intradialytic hypotension: recommendations from the Pediatric Continuous Renal Replacement Therapy (PCRRT) Workgroup

Intradialytic hypotension (IDH) is a common adverse event resulting in premature interruption of hemodialysis, and consequently, inadequate fluid and solute removal. IDH occurs in response to the reduction in blood volume during ultrafiltration and subsequent poor compensatory mechanisms due to abnormal cardiac function or autonomic or baroreceptor failure. Pediatric patients are inherently at risk for IDH due to the added difficulty of determining and attaining an accurate dry weight. While frequent blood pressure monitoring, dialysate sodium profiling, ultrafiltration-guided blood volume monitoring, dialysate cooling, hemodiafiltration, and intradialytic mannitol and midodrine have been used to prevent IDH, they have not been extensively studied in pediatric population. Lack of large-scale studies on IDH in children makes it difficult to develop evidence-based management guidelines. Here, we aim to review IDH preventative strategies in the pediatric population and outlay recommendations from the Pediatric Continuous Renal Replacement Therapy (PCRRT) Workgroup. Without strong evidence in the literature, our recommendations from the expert panel reflect expert opinion and serve as a valuable guide.

Osmolality and blood pressure stability during hemodialysis

Homeostatic regulation of plasma osmolality (POsm) is critical for normal cellular function in humans. Arginine vasopressin (AVP) is the major hormone responsible for the maintenance of POsm and acts to promote renal water retention in conditions of increased POsm. However, AVP also exerts pressor effects, and its release can be stimulated by the development of effective arterial blood volume depletion. Patients with end-stage renal disease on hemodialysis, particularly those with minimal or no residual renal function, have impaired ability to regulate water retention in response to AVP. While hemodialysis can assist with this task, patients are subject to relatively rapid shifts in volume and electrolytes during the procedure. This can result in the development of transient osmotic gradients that lead to the movement of water from the extracellular to the intracellular space. Hypotension may result-both as a consequence of water movement out of the intravascular compartment, but also from impaired AVP release and inadequate vascular tone. In this review, we explore the evidence for POsm changes during hemodialysis, associations with adverse outcomes, and methods to minimize the rapidity of changes in POsm in an effort to reduce patient symptoms and minimize intra-dialytic hypotension.

Effect of the decrease in dialysate sodium in pediatric patients on chronic hemodialysis

Optimal dialysate sodium (dNa) is unknown, with both higher and lower values suggested in adult studies to improve outcomes. Similar studies in pediatric hemodialysis (HD) population are missing. This is the first report of the effect of two constant dNa concentrations in pediatric patients on chronic HD. 480 standard HD sessions and interdialytic periods were studied in 5 patients (age 4-17 years, weight 20.8-66 kg) during a period of 6-11 months per patient. dNa was 140 mEq/L during the first half, and 138 mEq/L during the second half of the study period for each patient. Lowering dNa was associated with improved preHD hypertension, decreased interdialytic weight gain, decreased need for ultrafiltration, lower sodium gradient and was well tolerated despite lack of concordance with predialysis sNa, that was variable. Further studies are needed to verify our findings and to investigate if an even lower dNa may be more beneficial in the pediatric HD population.

Intradialytic hypotension

Intradialytic hypotension (IDH) is common in children during conventional, 4 hour haemodialysis (HD) sessions. The declining blood pressure (BP) was originally believed to be caused by ultrafiltration (UF) and priming of the HD circuit, however emerging data now supports a multifactorial aetiology. Therefore strategies to improve haemodynamic stability need to be diverse and address specific patient requirements or risks. In the treatment of IDH immediate action is required to stop or reduce the severity of symptoms that may precede or follow. Typically UF is slowed or stopped, a fluid bolus is given and in resistant cases the HD session is prematurely discontinued. Patients complete their treatment under-dialysed and volume expanded. Chronically, repeated episodes of IDH cause devastating, multi-system morbidity with an increased risk of mortality. This had provided the impetus for more haemodynamically friendly dialysis prescriptions that attenuate the risk of IDH. During pediatric HD several preventative strategies have been tested but with variable success. Of these, dialysate sodium profiling, UF guided by relative blood volume (RBV) algorithms, cooling and intradialytic mannitol appear to be the most effective. However in refractory cases one may be left with no option but to switch dialysis modality to haemodiafiltration (HDF) or more frequent or prolonged HD regimens.

First experience with the Prismaflex HF 20 set in four infants

PURPOSE

Renal replacement therapy (RRT) in infants is challenging due to a lack of widely available technology that is specific to this patient population. We present our initial experience with the newly developed Prismaflex HF20 disposable set used on the Prismaflex device in infants with renal failure.

PATIENTS

Four infants, age 5 to 24 months, were enrolled. Overall 120 treatment sessions were performed over 300 patient-days. Treatment monitoring included patient weight change and fluid balance, treatment efficacy, number of interventions, and alarms.

RESULTS

Desired fluid balance according to the prescribed weight loss was achieved in all patients (R²=0.86, p<0.0001). Treatment efficacy was monitored by blood urea nitrogen (BUN) and serum creatinine values at the start of RRT (59 ± 17 mg/dL and 5.1 ± 1.1 mg/dL) and their decrease after 4 hours of RRT (23 ± 7 mg/dL and 2.2 ± 0.6 mg/dL). Measured urea and creatinine clearances for the HF20 filter were 23 ± 7 ml/min and 19 ± 4 ml/min, respectively. No complications occurred.

CONCLUSION

This is the first report on the use of the Prismaflex HF20 set in infants. No adverse events were observed, treatments were well tolerated in all patients, and flow rate adaptability to infants' needs was good.

The value of sequential dialysis, mannitol and midodrine in managing children prone to dialysis failure

The uremic state impairs compensatory responses to ultrafiltration (UF). Intradialytic symptoms and hypotension can result and lead to premature discontinuation of treatment and sub-optimal dialysis. We report the benefits of mannitol, sequential dialysis and midodrine in reducing dialysis failures in those children prone to intradialytic hypotension. Prophylactic mannitol halved the odds of intradialytic symptoms and hypotension and increased UF volumes. Sequential dialysis halved the odds of symptoms but hypotension persisted. In one patient with refractory hypotension, only intradialytic midodrine consistently maintained acceptable intradialytic blood pressures, reduced intradialytic symptoms and increased the UF potential.

Importance of the curve shape for interpretation of blood volume monitor changes during haemodiafiltration

In children, the prescribed ultrafiltration needed to achieve the fixed end session dry weight can induce hypotensive episodes. A variety of on-line devices based on the direct measurement of the hematocrit are available, but these devices nearly always only measure the quantitative variation in the blood volume as the means of identifying a hypotensive occurrence risk. In February 2002, our unit began using an on-line hematocrit measurement available even with infants' blood lines. Since January 2004, this blood volume monitor (BVM) has been used routinely in all dialysis sessions, and 2240 BVM data sets have been recorded and analysed during the last 4 years. Based on our analysis of these data sets, we have determined that, in addition to the described threshold points, which provide a quantitative analysis of the BVM, the qualitative analysis of the BVM, the so-called curve shape, is also of clinical importance. In 91% of the sessions analysed, a very similar "symptom-free" curve shape was noted that consisted of an initial decrease, followed by the BV reaching a "stable" plateau. Additional curve shapes were identified: one with no BV decrease, presumably indicating an overload risk state, and one with a continuous BV decrease, presumably indicating an hypovolemic risk state. In our experience, only 2% of the patients had relevant clinical symptoms that were not visible by BVM.