DO NOT USE FOR CLINICAL PRACTICE
Please use current guidelines available on the UHNM intranet for patient treatment
Please use current guidelines available on the UHNM intranet for patient treatment
RECOGNITION AND ASSESSMENT
- Plasma potassium >6 mmol/L (normal 3.0–5.5 lithium heparin specimen)
- Babies often tolerate concentrations up to 7.5–8.0 mmol/L without ECG changes
SYMPTOMS AND SIGNS
- Cardiac arrest
- ECG abnormalities (see below):
- tall peaked T waves
- widened QRS complex
- sine waves (widened QRS complex merging with T wave)
- prolonged PR interval, bradycardia, absent P wave
Tall, peaked T wave, widening of QRS
Sine wave QRS complex (before cardiac arrest)
RISK OF ARRHYTHMIA
- ECG changes as above
- Rapid rise in potassium >7 mmol/L
- Ca2+ and Mg2+ below normal range
- Oliguria
- Acute kidney injury
- Known cardiac disease
CAUSES
- Renal failure: secondary to hypoxic ischaemic encephalopathy, sepsis and hypotension, post major surgery, structural abnormalities and nephrotoxic drugs
- Cellular injury with potassium release e.g. large intraventricular haemorrhage, haemolysis
- Very-low-birth-weight babies without renal failure (non-oliguric hyperkalaemia) in first 12–48 hr
- Excess potassium in IV solutions
- Endocrine (congenital adrenal hyperplasia, pseudohypoaldosteronism)
INVESTIGATIONS
- Confirm hyperkalaemia. Send free-flowing venous or arterial laboratory sample to avoid haemolysed sample. Be guided by capillary gas sample in the meantime
- If potassium >6.0 mmol/L, send Ca2+, Mg2+, Cl-, glucose and urinalysis to guide treatment and help identify cause
- If potassium >6.0 mmol/L, commence continuous ECG monitoring and assess for risk of arrhythmia (see above)
IMMEDIATE TREATMENT
Serum potassium >6.0 mmol/L (stable with normal ECG)
- Stop all sources of potassium including IV solutions (check PN) and oral supplements
- Stop all potassium-retaining drugs and potassium-sparing diuretics e.g. spironolactone
- Avoid suxamethonium
- Review and withhold nephrotoxic drugs e.g. gentamicin
- Recheck U&E 4–6 hrly
Serum potassium >7.0 mmol/L without ECG changes
- As above
- Inform consultant
- Give salbutamol 4 microgram/kg IV in glucose 10% over 5–10 min; effect evident within 30 min but sustained benefit may require repeat infusion after at least 2 hr
- Give furosemide 1 mg/kg IV
- If serum potassium still >7.0 mmol/L, give soluble insulin 0.1 units/kg IV in 10 mL/kg 10% glucose over 30 min; very effective and has an additive effect with salbutamol
- Repeat U&E 2–3 hrly
- Repeat insulin infusion as necessary until potassium <7.0 mmol/L
- Monitor blood glucose every 15 min for first 2 hr during and after infusion
- aim for blood glucose 4.0–7.0 mmol/L
- Give sodium bicarbonate 1 mmol/kg (2 mL of sodium bicarbonate 4.2% = 1 mmol) if:
- pH <7.23 or
- BE more negative than -8 or
- bicarbonate <14 mmol/L
- Correct other electrolyte abnormalities
- Maintain ionised Ca2+ >1 mmol/L
Serum potassium >7.5 mmol/L with ECG changes
- As above, but first institute emergency measures below:
- give calcium gluconate 10% 0.5 mL/kg IV/CVL over 5–10 min
- infuse centrally were possible; does not reduce potassium but stabilises myocardium
- flush line with sodium chloride 0.9% or preferably use a different line
- always give separately to bicarbonate or PN (calcium gluconate must not come into contact with any other IV administered drug)
- give sodium bicarbonate (1 mmol/kg IV over 2 min). Effective even in babies who are not acidotic (2 mL of sodium bicarbonate 4.2% = 1 mmol)
- give calcium gluconate 10% 0.5 mL/kg IV/CVL over 5–10 min
- Repeat U&E hourly
Further treatments: discuss with consultant
- A cation-exchange resin, such as calcium resonium (500 mg/kg rectally, with removal by colonic irrigation after 8–12 hr, repeat every 12 hr. Dose can be doubled at least once to 1 g/kg in severe hyperkalaemia). Useful for sustained reduction in serum potassium but takes many hours to act and is best avoided in sick preterms at risk of necrotising enterocolitis
- If severe hyperkalaemia persists despite above measures in term babies with otherwise good prognosis, contact renal team for consideration of dialysis or exchange transfusion (see Exchange transfusion guideline)
SUBSEQUENT MANAGEMENT
- Recheck serum potassium after each intervention or:
- 4–6 hrly in stable/well baby with potassium <7 mmol/L and no ECG changes
- 2–3 hrly in unwell baby and/or potassium >7 mmol/L with no ECG changes
- hourly when arrhythmias or ECG changes present with/without renal failure
- Monitor urine output and maintain good fluid balance
- If urine output <1 mL/kg/hr, unless baby volume depleted, give furosemide 1 mg/kg IV until volume corrected
- Treat any underlying cause (e.g. renal failure)
- Review need for further investigations for underlying cause e.g. 17OHP for congenital adrenal hyperplasia