Pediatric hyperkalemia management rapid overview

Clinical features

Serum potassium level 5 to 7 mEq/L – Generally asymptomatic.

Serum potassium level greater than 7 mEq/L – Muscle weakness, paralysis, and cardiac changes on ECG and arrhythmias. Sudden arrest may occur.

Causes

Pseudohyperkalemia, usually due to hemolysis of the blood specimen, is the most likely cause of an elevated serum or plasma potassium level in children. It does not reflect true hyperkalemia and is not associated with cardiac conduction disturbances.

The 2 major mechanisms of true hyperkalemia and their major causes are:

Increased potassium release from cells, most commonly due to rhabdomyolysis (eg, crush injury, prolonged seizure, hyperthermia, or exercise), tumor lysis syndrome, massive transfusion, and metabolic acidosis
Reduced urinary potassium excretion, most commonly due to severe hypovolemia, impaired kidney function, or hypoaldosteronism (eg, adrenal insufficiency)

Laboratory evaluation

Laboratory tests are based on probable etiology. All patients with true hyperkalemia should have the following tests obtained:

BUN
Creatinine
Blood glucose
Serum electrolytes
Urinalysis
Urine electrolytes

In cases where rhabdomyolysis is suspected, the following studies are also indicated:

Serum creatine kinase and lactic dehydrogenase
Urine for myoglobin
Blood gas

In cases where adrenal insufficiency is suspected, additional testing includes:

Serum cortisol and ACTH (prior to administration of exogenous corticosteroids)

ECG changes^*

ECG findings commonly progress as follows:

Peaked T waves
Prolonged PR and QRS intervals and small P waves
Loss of P wave, further prolongation of QRS interval ("sine wave" pattern), and conduction delay that can manifest as bundle branch or atrioventricular nodal block
Ventricular fibrillation or asystole

Management

Confirm that the patient is truly hyperkalemic (ie, exclude pseudohyperkalemia) by obtaining a venous or arterial blood sample that is not hemolyzed for rapid analysis.

Obtain ECG, and place patient on a cardiac monitor.

The following specific therapies are listed according to their effectiveness and rapidity of action; the choice of intervention depends on the severity of ECG changes and muscle weakness:

Stabilize cardiac membranes with calcium:

Give only for hyperkalemia with significant ECG findings (eg, widening of the QRS complex or loss of P waves, but not peaked T waves alone) or severe arrhythmias thought to be caused by hyperkalemia or in patients with a potassium level ≥7 mEq/L.
For perfusing patients, give calcium gluconate 10% solution 60 mg/kg; given as 0.6 mL/kg diluted in an equal volume of D5W or NS, maximum 2 g (20 mL, 4.5 mmol) per dose IV or IO over 5 minutes. Time to onset of action is immediate. May repeat in 10 minutes as needed for persistent ECG changes or arrhythmias^¶.
For cardiac arrest, give calcium chloride 10% solution 20 mg/kg given as 0.2 mL/kg, maximum 2 g (20 mL, 14 mmol) per dose; dilute in an equal amount of D5W or NS, and give slow IV via central venous access or IO push; repeat in 10 minutes as needed for persistent arrest, ECG changes, or arrhythmias^Δ.
Calcium gluconate is a vesicant but can be safely administered through a free-flowing peripheral line in patients with life-threatening hyperkalemia at the dilution shown. Peripheral administration of calcium chloride is not recommended. Sodium bicarbonate should not be administered in the same line as calcium solutions, because of the potential for precipitation.
Because the effect of calcium is transient, patients with hyperkalemia also require concomitant or immediate treatments to shift potassium into cells and remove potassium.

Shift potassium into cells:

Insulin and glucose – Onset of action is 10 to 20 minutes. Only give if significant ECG changes or confirmed serum potassium ≥7 mEq/L.

Give regular insulin (dose of 0.1 units per kg, maximum dose of 10 units) along with dextrose (glucose) dose of 0.5 g/kg over 30 minutes. The administration of dextrose is based on the age of the patient as follows:

Children younger than 5 years of age – Give 10% dextrose (100 mg/mL) at a dose of 5 mL/kg
Children 5 years of age and older – Give 25% dextrose (250 mg/mL) at a dose of 2 mL/kg

For patients with severe acute symptoms, ECG changes, arrhythmias, or impending arrest – Larger doses of regular insulin (0.2 units/kg) and dextrose (1 g/kg, 10 mL/kg of 10% dextrose or 4 mL/kg of 25% dextrose) can be administered.

Repeat dosing can be given after 30 minutes if needed. The major adverse effect is hypoglycemia, and serum glucose level should be monitored closely and additional dextrose administered as needed.

Beta-2 agonist – Onset of action is 20 to 30 minutes.

Give nebulized albuterol (salbutamol) with dosing based on patient weight as follows:

Neonates – 0.4 mg in 2 mL of saline
Infants and small children <25 kg – 2.5 mg in 2 mL of saline
Children between 25 and 50 kg – 5 mg in 2 mL of saline
Older children and adolescents >50 kg – 10 mg in 2 to 4 mL of saline (doses up to 20 mg have been used)

Inhalation may be repeated after 20 minutes. Inhaled albuterol may also be administered by metered-dose inhaler as 4 to 8 puffs with spacer.

Sodium bicarbonate – Onset of action is 15 minutes. Provides minimal effect on shifting potassium intracellularly and should not be the only therapy used in the management of hyperkalemia, even in acidotic children.

Give 1 mEq/kg (1 mmol/kg). Maximum single dose of 50 mEq (50 mmol), which can be provided as 1 mL/kg of 8.4% solution or, for children younger than 6 months of age, 2 mL/kg of 4.2% solution administered over 10 to 15 minutes.

A repeat dose may be given 10 to 15 minutes after last administration. Do not give in the same IV line as calcium, because of a risk of precipitation.

Remove potassium; since the effect of above therapies is transient, treatments to remove potassium are also required.

Stop all potassium intake.

Loop diuretic – Provides only limited short-term effect. Give furosemide 1 mg/kg IV (maximum single dose of 40 mg); higher dose may be required with kidney function impairment; fluid losses must be replaced unless the patient is volume expanded. The onset of effect is 1 to 2 hours. May be repeated after 6 hours.

Cation exchange resin (sodium polystyrene sulfonate) – Give sodium polystyrene sulfonate (without sorbitol) at a dose of 1 g/kg (maximum dose of 30 g) orally, through nasogastric tube, or as a retention enema. 1 g of resin will bind 1 mEq (mmol) of potassium. Onset is approximately 1 to 2 hours; may repeat dose after 4 to 6 hours based on repeat serum potassium.

Sodium polystyrene sulfonate should not be used in preterm neonates, term neonates with intestinal hypomotility and/or those at risk for necrotizing enterocolitis, postoperative patients, or those with bowel obstruction or ileus. Sorbitol can cause intestinal necrosis and should be avoided. A laxative that contains no magnesium or potassium (eg, lactulose) is an alternative to sorbitol use to prevent colonic impaction.

Hemodialysis – In children unresponsive to diuretic or cation exchange resin therapy, or with severe kidney function impairment, dialysis may be necessary to remove excess potassium from the body. Hemodialysis is the preferred modality to reduce potassium levels as it is the quickest and most controlled kidney replacement treatment.

ACTH: adrenocorticotrophic hormone; BUN: blood urea nitrogen; D5W: dextrose 5% solution in water; ECG: electrocardiogram; IO: intraosseous; IV: intravenous; NS: normal saline.

* Large interpatient variability exists in the relationship between the serum potassium and ECG changes; at a given serum potassium, ECG changes are more common with acute elevations and less common with chronic elevations (eg, chronic kidney disease). Infants generally have a higher range of normal potassium levels, so ECG changes are usually observed at higher values.

¶ Conversions: 10% calcium gluconate = 100 mg/mL calcium gluconate = 9.3 mg/mL elemental calcium = 0.23 mmol/mL calcium; suggested dose of 60 mg/kg (perfusing patient) is equivalent to a dose of elemental calcium 5 mg/kg (0.15 mmol/kg) up to a maximum of 180 mg elemental calcium (4.5 mmol) per dose.

Δ Conversions: 10% calcium chloride = 100 mg/mL calcium chloride = 27.3 mg/mL elemental calcium = 0.68 mmol/mL calcium; suggested dose of 20 mg/kg (cardiac arrest) is equivalent to a dose of elemental calcium 5 mg/kg (0.15 mmol/kg) up to a maximum of 540 mg elemental calcium (14 mmol) per dose.

Graphic 85978 Version 11.0

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Pediatric hyperkalemia management rapid overview