Hyperosmolar solutions in continuous renal replacement therapy for hyperosmolar acute renal failure: a preliminary report

Dialysis disequilibrium on CKRT: avoiding the steep slippery slope

BACKGROUND

Current guidelines for initiation of kidney replacement do not include specific recommendations for prescription parameters and monitoring.

CASE OUTLINE

A 16-year-old girl presented with kidney failure with creatinine of 19.8 mg/dL and BUN of 211 mg/dL. She initiated continuous kidney replacement therapy (CKRT) with clearance of 1,300 mL/min/1.73 m² which was increased to 1,950 mL/min/1.73 m² at 17 h of stable therapy.

COMPLICATIONS

At 31 h of therapy, she developed generalized seizure activity. CT imaging was negative for acute intracranial process, and EEG demonstrated diffuse encephalopathy. CKRT was discontinued, and BUN was noted to be 47 mg/dL at that time (a 79% reduction from presenting BUN).

KEY MANAGEMENT POINTS

• The potential for development of DDS is not isolated to intermittent hemodialysis and may occur later in presentation. • A decreased clearance rate should be considered in those with risk factors for development of dialysis disequilibrium syndrome (DDS). • Frequent monitoring of BUN/serum osmolality is important to allow for adjustment of the KRT prescription following initiation of therapy. • Additional research is needed to guide risk assessment for DDS and therapeutic timing and goals in the early stages of KRT initiation. • Inclusion of more specific guidelines surrounding DDS would assist in providing important support for nephrologists.

LIST OF RELEVANT GUIDELINES

KDIGO clinical practice guideline for acute kidney injury [1] Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease [2] The Renal Association Clinical Practice Guideline Acute Kidney Injury (AKI) [3] The Japanese Clinical Practice Guideline for Acute Kidney Injury [4].

Prevention of Dialysis Disequilibrium by use of CVVH

Objective.

Dialysis disequilibrium occurs due to a rapid shift of osmols when hemodialysis is used in cases of extreme uremia. Continuous veno-venous hemofiltration (CVVH) with citrate anticoagulation may offer a safe method of urea reduction.

Design.

Retrospective, clinical observation.

Setting.

Tertiary pediatric intensive care unit and nephrology program.

Patients

Two males, ages 10 and 12 years of age.

Intervention.

CVVH with citrate anticoagulation.

Results.

Three to four day reduction of BUN from 180 mg/dL to 22 mg/dL and from 279 mg/dL to 23 mg/dL.

Conclusion.

Slow and safe improvement of severe urea, hyperphosphatemia, hypocalcemia, and anemia without untoward side effects.

Continuous renal replacement therapy: cause and treatment of electrolyte complications

Continuous renal replacement therapy (CRRT) has become the modality of choice for critically ill patients. Although often hemodynamically better tolerated than intermittent dialysis, the continuous nature of this therapy may cause significant electrolyte complications. These complications commonly result from removal of electrolytes from the body without adequate replacement or because of the use of trisodium citrate as the anticoagulant. Both hypophosphatemia and hypokalemia frequently complicate prolonged treatment. These complications can be avoided by adding these electrolytes to the dialysate or replacement fluid. The use of citrate, especially if this anticoagulant is not used routinely following established protocols, can also result in several electrolyte abnormalities. Because citrate works by chelating calcium, hypo- and hypercalcemia occur because of under- or overreplacement of calcium. Because citrate is a base equivalent, if the bicarbonate concentration of the dialysate or replacement fluid is not decreased, a metabolic alkalosis may develop. Less commonly, in patients with severe liver dysfunction who cannot metabolize citrate back to bicarbonate, a metabolic acidosis may develop. Although CRRT may cause electrolyte complication it also can be the treatment of choice for the correction of certain electrolyte complications. In patients with acute or chronic renal failure who present with significant dysnatremias, intermittent hemodialysis may cause overly rapid correction of the serum sodium with serious neurologic sequelae. The ability to manipulate the sodium concentration of the dialysate or replacement fluid and the more sustained nature of the treatment allows for a slower correction thus avoiding complications.

Extreme hypernatremia combined with rhabdomyolysis and acute renal failure

Rhabdomyolysis is a life-threatening condition that involves muscle cell destruction. Among its etiologies, severe hypernatremia is a less common cause. We report a teenage girl with congenital central hypoventilation syndrome and hypothalamus dysfunction syndrome who presented with extreme hypernatremia (sodium, 211 mmol/L) with rhabdomyolysis (creatine kinase, 32,850 U/L) and acute renal failure (creatinine, 6.1 mg/dL) following gastroenteritis with 7-kg weight loss. Rhabdomyolysis subsequently led to acute renal failure and hyperkalemia. Acute hemodialysis was initiated on hospital day 3 for hyperkalemia. This resulted in a 13 mmol/L fall in serum sodium in 3 hours despite using a 156 mmol/L sodium bath, but without the development of cerebral edema or neurological defect. This report highlights an unusual cause of rhabdomyolysis in children and the experience of managing such a difficult clinical situation.

Dialysis and pediatric acute kidney injury: choice of renal support modality

Dialytic intervention for infants and children with acute kidney injury (AKI) can take many forms. Whether patients are treated by intermittent hemodialysis, peritoneal dialysis or continuous renal replacement therapy depends on specific patient characteristics. Modality choice is also determined by a variety of factors, including provider preference, available institutional resources, dialytic goals and the specific advantages or disadvantages of each modality. Our approach to AKI has benefited from the derivation and generally accepted defining criteria put forth by the Acute Dialysis Quality Initiative (ADQI) group. These are known as the risk, injury, failure, loss, and end-stage renal disease (RIFLE) criteria. A modified pediatrics RIFLE (pRIFLE) criteria has recently been validated. Common defining criteria will allow comparative investigation into therapeutic benefits of different dialytic interventions. While this is an extremely important development in our approach to AKI, several fundamental questions remain. Of these, arguably, the most important are "When and what type of dialytic modality should be used in the treatment of pediatric AKI?" This review will provide an overview of the limited data with the aim of providing objective guidelines regarding modality choice for pediatric AKI. Comparisons in terms of cost, availability, safety and target group will be reviewed.