Diabetic ketoacidosis including fluid calculation sheet

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Objectives

Standardisation of the management of diabetic ketoacidosis in children, including an algorithm for intravenous fluid administration. 

Scope

Children with known or newly diagnosed diabetes mellitus. 

Audience

Medical and nursing staff that encounter this patient group. 

Overview
  • Make the diagnosis
  • Establish venous access
  • Fluids
  • Insulin
  • Monitoring Underlying cause

NB: There is no difference in the management of DKA in a new or established patient

Definition

  • Blood glucose > 11mmol/L
  • pH < 7.3
  • Bicarbonate < 15 mmol/L

AND

  • more than 5% dehydrated
  • and/or vomiting
  • and/or drowsy
  • and/or clinically acidotic

Features of DKA

  • Polyuria, polydipsia, incontinence
  • Thirst, polydipsia
  • Abdominal pain
  • Vomiting
  • Kussmaul breathing
  • Acetone on breath
  • Dehydration, hypotension, collapse
  • Disturbed consciousness
  • Coma

Features of shock

  • Poor capillary return
  • Impaired consciousness
  • BP may be normal or low
  • Thready, rapid pulse

NB Urine output may remain fair because of osmotic diuresis

Features of Cerebral Oedema

  • Headache
  • Irritability
  • Slowing of pulse
  • Rising blood pressure
  • Reducing conscious level

NB These features usually present a few hours after commencing treatment but can occur very early

Biochemical assessment and monitoring

Blood

All new diabetes patients

  • Glucose
  • U&Es including Bicarbonate
  • Thyroid function tests
  • FBC
  • HbA1c
  • 10ml plain tube for possible autoantibodies
  • (HISS Order Set /NEWDIA)

for DKA

  • Gases (venous usually sufficient)
  • Blood culture
  • Osmolality

Urine

All patients

  • Glucose, Ketones (test all urine and record results)

for DKA

  • Hourly volume, culture

Other monitoring etc in DKA

  • Measure current weight if at all possible
  • BP
  • ECG monitor
  • Nil by mouth NG Tube if unconscious or evidence of gastric distention
  • Neuro-obs

Repeat biochemistry frequently (~2hrly) until patient stable

Fluids for DKA - use with DKA IV Fluid Calculation Sheet (below)

Weigh the child and compare with previous known weights and centile charts - access the electronic medical record for existing patients.

  1. Treat shock with 10ml/kg N Saline. May repeat once before discussing with a consultant.

  2. Calculate fluid deficit - see A, B, C and D on calculation sheet

  3. Determine maintenance fluid volume per kg from age:
    0-2 years 160ml per kg
    3-5 years 140ml per kg
    6-9 years 120ml per kg
    10-14 years 100ml per kg
    >14.9 years 60ml per kg
    (NB Maintenance calculation is for 48 hours)

  4. Calculate hourly fluid rate (for 48h)
    Hourly Rate (ml) = [48h MAINTENANCE (C x E) + DEFICIT (D x 1000)] - Volume used to treat shock
    48
     

  5. Double check all calculations and have someone else do so independently - if you are in any doubt ASK
DKA treatment - which fluids?

General Points:

Treat shock (resuscitate) with Normal Saline

Sodium Bicarbonate is very rarely indicated and may be harmful - only consider in Intensive Care Unit after discussion with consultant - dose would be 0.5mmol/kg over 30 minutes

Potassium can usually be added to bags immediately after resuscitation (assuming urine output) - 20 mmol/500ml. Monitor T waves and adjust KCl according to electrolyte results. Insulin makes K fall.

Phosphate - it is normal for patients in DKA to have a low phosphate level as this is a plasma buffer. There is no evidence to support adding additional phosphate.

Initially use 0.9% saline

Generally, once the blood glucose has fallen to 14 mmol/l add glucose to the fluid.

If this occurs within the first 6 hours, the child may still be sodium depleted. It may be preferable therefore to continue with NORMAL saline and added dextrose until the biochemistry is more stable.

If this occurs after the first 6 hours and the child’s plasma sodium level is stable, change the fl uid type to 0.45% saline/5% dextrose.

After 1st 12h, and assuming that the patient is improving, if they have already changed to 0.5N Saline + 5% Dextrose, there is no need to change back to Normal Saline if glucose > 14mmol/L - ADJUST the INSULIN

DKA treatment: insulin

Insulin is essential to switch off ketogenesis

Make up a solution of 1 unit per ml. of human soluble insulin (e.g. Actrapid) by adding 50 units (0.5 ml) insulin to 49.5 ml 0.9% saline in a syringe pump. Attach this using a Y-connector to the IV fluids already running.

 

Do not add insulin directly to the fluid bags

Run at 0.1 units/kg/hour (0.1ml/kg/hour).

If the rate of blood glucose fall exceeds 5 mmol/l per hour, or falls to around 14 mmol/l, add dextrose (5-10% equivalent) to the IV fluids running (see “fluids” above). The insulin dose needs to be maintained at 0.1 units/kg/hour to switch off ketogenesis.

Do not stop the insulin infusion while dextrose is being infused, as insulin is required to switch off ketone production. If the blood glucose falls below 4 mmol/l, give a bolus of 2 ml/kg of 10% dextrose and increase the dextrose concentration of the infusion.

10% dextrose with 0.45% saline can be made up by adding 7.5ml NaCl 30% to 500ml 10% Dextrose. (remember to consider if KCl required)

Once the pH is above 7.3, the blood glucose is down to 14-17 mmol/l, and a dextrose-containing fluid has been started, consider reducing the insulin infusion rate, but to no less than 0.05 units/kg/hour.

Blood glucose rises out of control, or the pH level is not improving after 4-6 hours consult senior medical staff, re-evaluate (possible sepsis, insulin errors or other condition), and consider starting the whole protocol again.

DKA treatment: cerebral oedema

Symptoms and Signs:

  • Headache, slowing of heart rate, rise in BP
  • Change in neurological status - restelessness, irritability, drowsiness, incontinence.
  • Specific neurological signs e.g. cranial nerve palsies
  • Abnormal posturing

Highest risk 12-18h after beginning rehydration

Inform senior staff immediately

Treat in ICU         Document carefully

Management:

Exclude hypoglycaemia as a possible cause of any behaviour change

Give Mannitol 1 g/kg stat (= 5 ml/kg Mannitol 20% over 20 minutes) or hypertonic saline (5-10 mls/kg over 30 mins). This needs to be given as soon as possible if warning signs occur.

Restrict IV fluids to 2/3 maintenance and replace deficit over 72 rather than 48 hours

Discuss with PICU consultant (if assisted ventilation is required maintain pCO2 above 3.5 kPa)

Once the child is stable, exclude other diagnoses by CT scan - other intracerebral events may occur (thrombosis, haemorrhage or infarction) and present similarly

A repeated dose of Mannitol should be given after 2 hours if no response

DKA Intravenous Fluids Calculations

 

This document has been taken from the Greater Glasgow & Clyde Children's Diabetes Service website: www.diabetes-scotland.org/ggc. Diabetes Scotland accept no responsibility for the use of the document outside of the Royal Hospital for Sick Children in Glasgow and RAH Paisley.

Please follow link to a pdf version for ONLINE completion - Recommended (NB Has to be loaded into Acrobat Reader or Acrobat Full Software - won't work automatically in all browsers): http://www.diabetes-scotland.org/ggc/documents/pdf_files/DKA%20Calc%20v%202011_1.pdf

A pdf version for printing only can be found here: http://www.diabetes-scotland.org/ggc/documents/pdf_files/DKA%20Calc%20v%202011_1_print.pdf

References
Editorial Information

Last reviewed: 01 September 2016

Next review: 01 September 2019

Author(s): Kenneth Robertson / Ian Craigie