How should I initiate fluid replacement therapy in a patient with DKA, and what monitoring is required?

Diabetic ketoacidosis (DKA) is a medical emergency that requires prompt management with close monitoring and careful correction of fluid and electrolyte imbalances, often necessitating hospital admission ²,³.

Initiating Fluid Replacement Therapy:

• For patients with DKA who are not alert, are nauseated or vomiting, or are clinically dehydrated, intravenous fluids should be used ¹. Oral fluids should not be given if the patient is receiving intravenous fluids for DKA, unless ketosis is resolving, they are alert, and not nauseated or vomiting ¹.
• For clinically dehydrated patients not in shock, give an initial intravenous bolus of 10 ml/kg 0.9% sodium chloride over 30 minutes ¹. A second 10 ml/kg bolus of 0.9% sodium chloride should only be considered if needed to improve tissue perfusion after reassessment, and discussion with a senior paediatrician is required before giving more than one bolus ¹.
• For patients showing signs of shock (weak, thready pulse and hypotension), an initial intravenous bolus of 10 ml/kg 0.9% sodium chloride should be given as soon as possible ¹.
• The total fluid requirement for the first 48 hours is calculated by adding the estimated fluid deficit to the fluid maintenance requirement ¹. For mild-to-moderate DKA (blood pH 7.1 or above), assume 5% dehydration; for severe DKA (blood pH below 7.1), assume 10% dehydration ¹. The deficit should be replaced evenly over the first 48 hours ¹. The Holliday–Segar formula is used for maintenance: 100 ml/kg for the first 10 kg, 50 ml/kg for the second 10 kg, and 20 ml/kg for every kg thereafter, with a maximum weight of 75 kg in the calculation ¹. Any initial bolus volumes should be subtracted from the total fluid deficit, unless the patient is in shock ¹.
• Use 0.9% sodium chloride without added glucose for both rehydration and maintenance until the plasma glucose concentration is below 14 mmol/litre ¹.
• Include 40 mmol/litre (or 20 mmol/500 ml) potassium chloride in all fluids (except initial boluses), unless the patient has anuria or their potassium level is above the normal range ¹. Do not delay potassium replacement, as hypokalaemia can occur once insulin infusion starts ¹. If potassium levels are above normal, only add potassium chloride if potassium is less than 5.5 mmol/litre or they have a history of passing urine ¹. For patients with hypokalaemia at presentation, include potassium chloride in intravenous fluids before starting the insulin infusion ¹.
• Monitor sodium levels throughout DKA treatment and calculate corrected sodium initially to identify hyponatraemia ¹. Be aware that falling serum sodium can indicate possible cerebral oedema, while a rapid and ongoing rise may also be a sign of cerebral oedema ¹.

Monitoring Requirements:

• At least hourly: Monitor and record capillary blood glucose, heart rate, blood pressure, temperature, respiratory rate (checking for Kussmaul breathing), fluid balance (input and output charts), and level of consciousness (using modified Glasgow Coma Scale) ¹.
• Every 30 minutes: For children under 2 years or those with severe DKA (blood pH below 7.1), monitor and record level of consciousness (modified Glasgow Coma Scale) and heart rate (to detect bradycardia) due to increased risk of cerebral oedema ¹.
• Continuous ECG: Monitor for signs of hypokalaemia (e.g., ST-segment depression, prominent U-waves) ¹.
• Blood tests: At 2 hours after starting treatment, and then at least every 4 hours, carry out and record laboratory measurements of glucose, blood pH and pCO2, plasma sodium, potassium, urea, and beta-hydroxybutyrate ¹.
• Doctor review: A doctor involved in the patient's care should review them face-to-face at diagnosis and then at least every 4 hours, or more frequently if they are under 2 years, have severe DKA, or other concerns ¹. During review, assess clinical status (vital signs, neurological status), blood investigation results, ECG trace, and cumulative fluid balance record ¹.
• Cerebral Oedema: Immediately assess for suspected cerebral oedema if there are early manifestations such as headache, agitation/irritability, unexpected fall in heart rate, or increased blood pressure ¹. Start treatment immediately if cerebral oedema is suspected or if signs like deterioration in consciousness, abnormal breathing patterns, oculomotor palsies, or pupillary inequality/dilatation are present ¹.
• Ensure healthcare professionals performing monitoring know what to look for and when to seek advice ¹.