Fluid replacement is the most important initial therapeutic intervention in DKA and is aimed at
- correction of hypotension by restoration of circulatory volume;
- clearing ketones
- correction of electrolyte imbalance (1)
Once circulating blood volume has been restored, calculate fluid requirements according to the following formula:
requirement = maintenance + deficit – fluid already given
- deficit (litres) = % dehydration x body weight (kg)
- convert the results into ml
- for most children, use 5% to 8% dehydration to calculate fluids
- maintenance requirements (according to the weight):
- 0 – 12.9 kg - 80 ml/kg/24 hrs
- 13 – 19.9 kg - 65 ml/kg/24 hrs
- 20 – 34.9 kg - 55 ml/kg/24 hrs
- 35 – 59.9 kg - 45 ml/kg/24 hrs
- adult (>60 kg) - 35 ml/kg/24 hrs
Note:
- neonatal DKA will require special consideration and larger volumes of fluid than those quoted may be required, usually 100-150 ml/kg/24 hours)
- Advanced Paediatric Life Support (APLS) maintenance fluid rates over estimate requirement, particularly at younger ages. Add calculated maintenance (for 48 hrs) and estimated deficit, subtract the amount already given as resuscitation fluid, and give the total volume evenly over the next 48 hours. i.e - hourly rate = 48 hr maintenance + deficit – resuscitation fluid already given/48
Type of fluid
- initially use 0.9% saline with 20 mmol KCl in 500 ml, and continue this sodium concentration for at least 12 hours
- if a bag of 500 ml 0.9% saline with 5% glucose and 20 mmol is not available make up a solution as follows - withdraw 50ml 0.9% sodium chloride/KCl from 500ml bag, and add 50ml of 50% glucose (this makes a solution which is approximately 5% glucose with 0.9% saline with potassium)
- once the blood glucose has fallen to 14 mmol/l add glucose to the fluid
- after 12 hours, if the plasma sodium level is stable or increasing, change to 500ml bags of 0.45% saline/5% glucose/20 mmol KCl.
- if the plasma sodium is falling, continue with normal saline (with or without glucose depending on blood glucose levels)
- corrected sodium levels should rise as blood glucose levels fall during treatment. If they do not, then continue with Normal saline and do not change to 0.45% saline.
Check U & E's 2 hours after resuscitation is begun and then at least 4 hourly. Electrolytes on blood gas machine can be helpful for trends whilst awaiting laboratory results
Oral fluids are not allowed in severe dehydration, impaired consciousness & acidosis (N/G tube may be necessary in the case of gastric paresis).
- oral fluids (eg fruit juice/oral rehydration solution) should only be offered after substantial clinical improvement and no vomiting
- when good clinical improvement occurs before the 48hr rehydration period is completed, oral intake may proceed and the need for IV infusions reduced to take account of the oral intake (1)
Reference: