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

Mannitol Role in the Management of Intradialytic Hypotension

BACKGROUND, AREAS OF UNCERTAINTY

Intradialytic hypotension (IDH) is one of the most common complications of the hemodialysis procedure. Although there are no clear-cut answers as to the best strategy on the management of IDH, data suggest that the administration of osmotically active drugs may decrease the occurrence of blood pressure decline during dialysis. The use of mannitol for IDH management in hemodialysis patients is scarce. This article highlights the use and benefits of mannitol and to assess the role of mannitol role in the management of IDH.

DATA SOURCES

Primary literature identified through MEDLINE/PubMed database and Google Scholar with no restrictions. Relevant and current literatures related to mannitol and IDH were used.

RESULTS AND DATA SYNTHESIS

Multiple studies have shown the benefits of mannitol for the management of IDH. Because of its oncotic effect, mannitol increases plasma osmolality to maintain adequate blood pressure and prevent the occurrence of IDH. Two observational studies and several reports were identified as being the most recent and applicable to clinical practice. Studies and data on the use of mannitol in IDH are scarce or outdated. The 2 studies used in this article conclude that mannitol carries benefits for both the adult and pediatric population. However, additional research in the future will be needed to confirm the evidence for various age groups. These 2 observational trials were also very small in number, and any future studies conducted should have a longer duration and larger population size. Although lacking data, these studies will suffice in introducing the benefits of mannitol in IDH.

CONCLUSIONS

Mannitol may be considered for the management of IDH; however, additional studies are required to evaluate the long-term risk and benefits associated with mannitol, as it carries a risk of accumulation in the body.

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.

Hypertonic Mannitol for the Prevention of Intradialytic Hypotension: A Randomized Controlled Trial

RATIONALE & OBJECTIVE

Intradialytic hypotension (IDH) is a common complication at the initiation of hemodialysis (HD) therapy, is associated with greater mortality, and may be related to relatively rapid shifts in plasma osmolality. This study sought to evaluate the effect of an intervention to minimize intradialytic changes in plasma osmolality on the occurrence of IDH.

STUDY DESIGN

Double-blind, single-center, randomized, controlled trial.

SETTING & PARTICIPANTS

Individuals requiring initiation of HD for acute or chronic kidney disease.

INTERVENTION

Mannitol, 0.25g/kg/h, versus a similar volume of 0.9% saline solution during the first 3 HD sessions.

OUTCOMES

The primary end point was average decline in systolic blood pressure (SBP). The secondary end point was the proportion of total sessions complicated by IDH (defined as a decrease ≥ 20mm Hg from the pre-HD SBP). Exploratory end points included biomarkers of cardiac and kidney injury.

RESULTS

52 patients were randomly assigned and contributed to 156 study visits. There were no significant differences in average SBP decline between the mannitol and placebo groups (15±11 vs 19±16mm Hg; P = 0.3). The proportion of total sessions complicated by IDH was lower in the mannitol group compared to placebo (25% vs 43%), with a nominally lower risk for developing an episode of IDH (OR, 0.38; 95% CI, 0.14-1.00), though this finding was of borderline statistical significance (P = 0.05). There were no consistent differences in cardiac and kidney injury biomarker levels between treatment groups.

LIMITATIONS

Modest sample size and number of events.

CONCLUSIONS

In this pilot randomized controlled trial studying patients requiring initiation of HD, we found no difference in absolute SBP decline between those who received mannitol and those who received saline solution. However, there were fewer overall IDH events and a nominally lower risk for dialysis sessions being complicated by IDH in the mannitol group. A larger multicenter randomized controlled trial is warranted.

FUNDING

Government funding to an author (Dr Mc Causland is supported by National Institute of Diabetes and Digestive and Kidney Diseases grant K23DK102511).

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT01520207.

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.

Hemodialysis in children with ventriculoperitoneal shunts: prevalence, management and outcomes

BACKGROUND

Hemodialysis (HD) in children with a concomitant ventriculoperitoneal shunt (VPS) is rare. Registry data suggest that peritoneal dialysis with a VPS is safe, but little is known about HD in the presence of a VPS.

METHODS

We performed a 10-year survey to determine the prevalence of a VPS, complications and outcome in children with a VPS on HD in 15 dialysis units from the 13 countries participating in the European Pediatric Dialysis Working Group.

RESULTS

Eleven cases of HD with a VPS were reported (prevalence 1.33 %; 328 patient-months) and compared with prospective Registry data. The median age at start of dialysis was 9.6 [inter-quartile range (IQR) 1.0-15.0] years and median HD vintage was 2.4 (IQR 1.7-3.0) years. Dialysis was performed through a central venous line (CVL) and through an arteriovenous fistula in six and five children, respectively. Three CVL infections occurred in two children, but these children did not develop VPS infections or meningitis. Symptoms of hemodynamic instability were reported in six (55 %) children at least once per week, with hypotension or hypertension occurring in four of these children and nausea, vomiting and headaches occurring in two; four other children reported less frequent symptoms. Seizures on dialysis occurred in two children, at a frequency of less than once per month, with one child also experiencing visual disturbances. During follow-up (median 4.0; IQR 0.38-7.63 years), three children remained on HD and eight had a functioning transplant. No patients were switched to PD.

CONCLUSIONS

Hemodialysis in children with a VPS is safe, but associated with frequent symptoms of hemodynamic instability. No episodes of VPS infection or meningitis were seen among the children in the survey, not even in those with CVL sepsis.

Are serum to dialysate sodium gradient and segmental bioimpedance volumes associated with the fall in blood pressure with hemodialysis?

INTRODUCTION

A fall in blood pressure is the most common complication of outpatient hemodialysis. Several factors have been implicated, including serum sodium to dialysate gradient, ultrafiltration rate, and the amount of fluid to be removed during dialysis.

METHODS

We prospectively audited 400 adult patients attending for their routine midweek hemodialysis session, and recorded changes in mean arterial blood pressure (MAP).

RESULTS

Mean age 58.4 ± 16.6 years, 60.9% male, 30.7% diabetic, 36.8% Caucasoid, single pool Kt/V 1.57 ± 0.4, and median percentage change in MAP -6.7% (-14.1 to + 2.8). The percentage fall in MAP was greatest for those starting with higher MAPs (β 0.448 , F 67.5, p<0.001), greater serum sodium to dialysate sodium gradient (β 0.676, F 5.59, p = 0.019), and age (β 0.163, F 5.15, p = 0.024). In addition, the percentage fall in MAP was greater in those with the lowest segmental extracellular water/total body water (ECW/TBW) ratios in the right arm prior to dialysis (β -477.5, F 7.11, p = 0.008).

CONCLUSIONS

Falls in blood pressure are common during dialysis, and greater for those starting dialysis with the highest systolic pressures, greater dialysate to serum sodium concentration gradient, and also those with the least ECW in the arm. As such, segmental bioimpedance may be useful in highlighting patients at greatest risk for a fall in blood pressure with dialysis.

Preservation of blood pressure stability with hypertonic mannitol during hemodialysis initiation

BACKGROUND

Intradialytic hypotensive events are common among hemodialysis patients and are associated with a variety of patient- and procedure-related factors, including intradialytic decline in plasma osmolality. Prior studies and practice have suggested that administration of osmotically active drugs may ameliorate blood pressure decline during chronic hemodialysis.

METHODS

Clinical and treatment data were collected for 102 consecutive patients requiring initiation of renal replacement therapy in 2 major teaching hospitals. Routine administration of mannitol differed according to institutional protocols, allowing its examination as the primary exposure of interest. Generalized linear models were fit to estimate associations of mannitol use during dialysis initiation with intradialytic blood pressure, as assessed by: (1) intradialytic blood pressure decline; (2) nadir intradialytic blood pressure; (3) absolute systolic blood pressure <90 mm Hg or decline >20 mm Hg.

RESULTS

Mean age was 62 years (±16), 70% were male and 44% were diabetic. Mean predialysis and nadir systolic blood pressure were 142 mm Hg (±29) and 121 mm Hg (±26), respectively. Mannitol administration was associated with a lesser decline in intradialytic blood pressure, a higher nadir blood pressure and fewer hypotensive events requiring intervention. No effect modification was evident according to diabetes or acuity of kidney disease (chronic vs. acute).

CONCLUSIONS

Mannitol administration appears to preserve hemodynamic stability during hemodialysis initiation. Randomized controlled trials are needed to confirm these findings and identify optimal management strategies to prevent intradialytic hypotension.

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.