Pediatric emergency medicine trisk 2868 2868
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To be employed if conservative measures fail after discussion with
nephrology consultant
Several therapies are aimed at shifting potassium into the intracellular
space and are outlined in Table 100.6 . Insulin drives movement of
potassium into the cell. This can be achieved by administering a
combination of 0.1 units/kg of regular insulin and 0.5 g/kg of dextrose. The
time of onset is 15 to 30 minutes, peak effect at approximately 60 minutes,
and duration of several hours. Providing sodium bicarbonate raises the
systemic pH and promotes hydrogen movement out of the cells
accompanied by potassium movement into the cells. This is most effective
in patients with metabolic acidosis. In the absence of acidosis, sodium
bicarbonate is not routinely recommended because it is less likely to be
effective, and may lead to other complications. The onset of the effect of
sodium bicarbonate is within 15 to 30 minutes and persists for several
hours. β2 - Adrenergic agonists promote transcellular shift of potassium, so
nebulized albuterol may provide further benefit. It is particularly useful if
IV access is not available. Recommended doses of albuterol are 0.4 mg for
neonates, 2.5 mg for infants and children under 25 kg, 5 mg for children 25
to 50 kg, and 10 mg for patients over 50 kg. Alternatively, albuterol may be
given as four to eight puffs with a metered dose inhaler with a spacer.
Though slower in onset than measures applied to shift potassium into the
intracellular space, efforts to remove potassium are necessary in cases of
total body potassium excess. Sodium polystyrene sulfonate (Kayexalate) is
a commonly used ion exchange resin. Within the intestinal lumen, the resin
takes up potassium in exchange for sodium. To a lesser extent, the resin will
also exchange for calcium and magnesium, and therefore, electrolytes
should be monitored with frequent or prolonged dosing. In the past, the
resin has been administered with sorbitol to prevent associated constipation
and fecal impaction, but this combination has been associated with colonic
necrosis and perforation and is no longer recommended. The pediatric oral
dose is 1 g/kg provided every 4 to 6 hours as necessary, with a maximum
dose of 30 g. Laxatives such as polyethylene glycol 3350 or lactulose may
be given to counteract the constipating effects of the polystyrene sulfonates.
Kayexalate may be given rectally at the same dose every 2 to 6 hours,
