Electrolyte Abnormalities

Hypernatraemia

Hyponatraemia

Hyperkalaemia

Hypokalaemia

Hypocalcaemia

Hypomagnesaemia

Hypernatraemia

• Serum Na⁺ > 150 mmol/l.
• Dehydration is a common cause.
• If shocked, give 10 ml/kg 0.9% Saline (NaCl) IVI
• Continue with maintenance fluids and volumes (Avoid intravenous solutions with excessive sodium).
• Give an additional 25-50 ml/kg 5% Dextrose-water (DW) over 24 hours.
• Serum Na⁺ should not be decreased more than 0.5 mmol/l per hour
• If  Na⁺ decrease is too rapid, change 5% DW to 0.45% Saline
  Repeat serum  Na⁺ levels 12 hourly till serum Na⁺ is 140 mmol/l
• Inform consultant of any baby with hypernatraemia

Hyponatraemia

Serum Na⁺ < 135 mmol/l

Establish the cause.

If serum Na⁺  128 – 134 mmol/l:

• Administer 1 ml of 5% NaCl per feed (2 hourly) and check serum Na⁺ after 24 hours
  

If serum Na⁺  < 128 mmol/l:

• Administer the deficit Na⁺  with IV 5% NaCL at a rate of 0.5 mmol  Na⁺  per hour (or 0.6 ml of 5% Na Cl) per hour.
  
• Check Serum Na⁺ after 24 hours

Amount of Na⁺ required to correct deficit:

(140 - Na⁺ value) x mass (kg) x 0.6 = mmol Na⁺

5% NaCl contains:

• 1 ml = 0.84 mmol Na⁺     (or  1mmol Na⁺ = 1.2 ml  Na⁺
• 10 ml = 8.4   mmol Na⁺

Hyperkalaemia

Serum potassium ≥ 7 mmol/l  (in 2 or more non-hemolysed non-capillary venous or arterial specimens).

Monitor: 

• Urine output
• Constant cardiac monitoring
• 12 Hourly serum electrolytes, urea, creatine, glucose, calcium

Management (in following order):

1. Stop all potassium administration (including Neonatalyte with K⁺)

• Use potassium free solutions, eg 5% DW and 0.2 % Na Cl or the Potassium free Neonatalyte/Neolyte

2. Calcium gluconate (10%)  1ml/kg IVI

• Administer slowly over 10 minutes (Over 1-3 minutes if ECG changes). Do not administer if hypercalcemic
  
• Can be repeated after 20 minutes. (Maximum 1 repeat dose)

3. Insulin/glucose:  

• 0.1 iu/kg insulin (Actrapid or Humulin) plus 1ml/kg 50% Dextrose over 30 minutes.
  
• Dilute the 50% Dextrose with 0.9% Saline if given via a peripheral IV. (Dilution ratio  1:3)
  
• Baby must be normoglycaemic before giving the Insulin/Glucose
  

4. Lasix:  1mg/kg  IVI

• Only if adequate perfusion

5. Sodabic (Na HCO₃) 4% :  2ml/kg IVI slowly over 15 minutes

• Only if acidotic (BE < -10)

6. Kayexalate:  

• 1g/kg per recum or per os every 6 hours in term baby NOT to be used in Preterm babies
• Dissolve 0.5 g Kayexalate in 1 ml NaCl (0.9%) for use as an enema or in 1 ml Dextrose water (5 - 10%) per os.
• Stop treatment if serum  K⁺  <6 mmol/l
• Inform consultant of any baby with hyperkalaemia

Hypokalaemia   

• Serum potassium < 3 mmol/l.
• Repeat blood K⁺ determination and inform registrar.
• Hypokalaemia can be restored as follows:

Chronic cases:

• Supplement with additional K. Give 3 mmol K⁺/kg/24 hours in 4 divided doses
  6 hourly.
• Use Potchlor^(R) (5 ml = 13 mmol K⁺)
• Repeat serum K⁺ after 12 - 24 hours.

Acute cases:

• 1 - 3 mmol K⁺/kg/24 hours IVI
• Infuse over 12 - 24 hours.
• Use 15% KCl solution (1 ml 15% KCl = 2 mmol K⁺).
• Intravenous fluid concentrations should never exceed a concentration of 4 mmol K⁺ per 100 ml.
• Repeat serum K⁺ 6 - 12 hourly.
• Remember Neonatolyte has a concentration of K⁺ = 1.5 mmol/100 ml.
• If the serum K⁺ < 2 mmol/l notify the consultant.

Hypocalcaemia

• Serum Calcium < 1.8 mmol/l (corrected).
• Correct with 10% Calcium gluconate solution, 1 - 2 ml/kg IVI over 10 - 30 minutes.
• Always dilute.  ADMINISTER IVI ONLY.  Monitor heart rate and stop infusion if the heart rate is < 100/min.
• Given as a continuous infusion 5 ml/kg/IVI over 24 hours.

Hypomagnesaemia    

• Serum magnesium < 0.8 mmol/l.
• Administer MgSO₄ (50% solution) 0.1 - 0.2 ml/kg/IMI or IVI (slow infusion).