Electrolyte Disturbances - Hyperkalaemia

Definition

Causes

Clinical features

ECG findings

Treatment

Glucose and insulin infusion

Definition 

• Defined as potassium > 5.9 mmol/l (neonate), 5.3mmol/l (infant), 4,7mmol/l (child). 
• Not uncommon, but always check the level again. 
• Rx with urgency as children may develop cardiac muscle instability 

Causes 

• Acidosis 
• Acute renal failure 
• Drugs: ACE inhibitors (Captopril); potassium sparing diuretics (Spironolactone) 
• Congenital adrenal hyperplasia (associated with ↓ Na+) 
• Toxins 

Clinical features 

• Muscle weakness: Flaccid paralysis, respiratory paralysis 
• Cardiac instability 
• ECG changes indication of severity 

ECG findings: 

• Peaked T waves 
• Wide QRS 
• Prolonged PR interval 
• Depressed P wave 

Treatment (If K+ > 6,5 Treat in stepwise fashion) 

1. Stop all supplements and K+ containing fluids (May need to change IV maintenance fluid). 
2. Give Calcium gluconate 0,5 ml/kg IV slowly → cardiac stabiliser, lasts for 30-60 minutes 
3. Salbutamol nebuliser → shifts K+ into cells. 
4. Frusemide 1mg/kg IV (if intravascular volume not depleted) 
5. 4,2 % Sodabic 2ml/kg IV slowly → not through same line as Ca+ as precipitation occurs. 
6. Kayexelate 0,5 – 1 g/kg orally or PR. Enhance gastrointestinal excretion. Contra-indicated in prems. 
7. Glucose + Insulin infusion → consult with a more senior doctor. 
8. Dialysis → discuss with Renal Team 

Glucose and insulin Infusion: 

• Needs to be used with care. Usually in bigger children or with resistant hyperkalaemia. 
• Use 200ml 10% DW add 4UActrapid/Novorapid to the solution (ie. 1u insulin :5g glucose) 
• Run at 5ml/kg/hr= 0.5g/kg/hr glucose = 0,1U/kg/hr insulin. 
• Monitor HGT closely! Blood glucose at least ½ hrly for 1hr then hrly for 6hrs.