Pediatric emergency medicine trisk 1866 1866
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TABLE 89.3
RISK FACTORS FOR CEREBRAL EDEMA IN DIABETIC KETOACIDOSIS
Elevated blood urea nitrogen
Low Pco2
Treatment with bicarbonate
Failure of measured serum [Na+ ] to rise steadily with correction of hyperglycemia
Age <3 yrs
New-onset diabetes
Once adequate intravascular volume is established, the fluid deficit should be replaced over
the next 48 hours. Classically, it has been recommended that during the first 4 to 6 hours of
this period, isotonic fluids should be used with appropriate additional electrolyte
supplementation as detailed below. The total body water deficit may be estimated based on a
clinical estimate of dehydration, or intravenous (IV) fluid may be administered at a rate
between one and one-half and two times maintenance fluid requirements (see Chapters 22
Dehydration and 100 Renal and Electrolyte Emergencies ). A 2018 randomized controlled trial
of fluid resuscitation in 1,389 episodes of DKA compared slow versus fast replacement of
isotonic (0.9% NS) versus hypotonic (0.45% NS) fluids and did not find differences in
neurologic outcomes suggesting a range of fluid protocols may be used to rehydrate children
with DKA. However, 98% of patients in this trial had GCS score ≥14, therefore, these
recommendations may not apply to the sickest patients, that is, those with GCS scores below
14. Urine output should be monitored and ongoing urinary losses in excess of 5 mL/kg/hr
(osmotic diuresis) should also be replaced.
The Na+ deficit typically approximates 10 mEq/kg body weight and Na+ maintenance is 3
mEq/100 mL of maintenance fluid. From a practical point of view, half-normal (0.45%) saline
can be started after the initial 4-hour period of isotonic fluids. The measured serum sodium
should rise as therapy progresses, and as blood glucose declines. If the initial serum sodium is
less than 136 mEq/L, or if the serum sodium falls with therapy, the IV fluid should be changed
to a more concentrated sodium solution, and the patient should be watched particularly closely.
Serum sodium failing to rise with therapy has been identified as a risk factor for cerebral
edema. Correcting the serum sodium for the degree of hyperglycemia may be useful in
following the patient’s total body sodium status:
Corrected [Na+ ] = measured [Na+ ] + [(glucose level − 100)
× 0.016].
All children with DKA can be assumed to be total-body potassium depleted (approximately
5 mEq/kg body weight); therefore, potassium replacement is an important part of therapy. If
the initial serum [K+ ] is 3 to 4.5 mEq/L, 40 mEq/L of potassium is added to the infusion after
vascular competency has been established and the child has urinated. If the serum [K+ ] is 4.6
to 5.0 mEq/L, only 20 mEq/L of potassium should be added, and if the [K+ ] is above 5.0
mEq/L, potassium should be withheld in the initial fluids. Generally, K+ is provided as
