Preventing a Drop in Effective Plasma Osmolality to Minimize the Likelihood of Cerebral Edema During Treatment of Children with Diabetic Ketoacidosis

Objectives

To test whether a drop in effective plasma osmolality (P_{Eff osm}; 2 × plasma sodium [P_Na] + plasma glucose concentrations) during therapy for diabetic ketoacidosis (DKA) is associated with an increased risk of cerebral edema (CE), and whether the development of hypernatremia to prevent a drop in the P_{Eff osm} is dangerous.

Study design

This study is a retrospective comparison of a CE group (n = 12) and non-CE groups with hypernatremia (n = 44) and without hypernatremia (n = 13).

Results

The development of CE (at 6.8 ± 1.5 hours) was associated with a drop in P_{Eff osm} from 304 ± 5 to 290 ± 5 mOsm/kg (P < .001). Control patients did not show this drop in P_{Eff osm} at 4 hours (1 ± 2 and 2 ± 2 vs –9 ± 2 mOsm/kg; P < .01), because of a larger rise in P_Na and/or a smaller drop in plasma glucose. During this period, the CE group received more near-isotonic fluids (69 ± 9 vs 35 ± 2 and 27 ± 3 mL/kg; P < .001). The CE group had a higher mortality (3/12 vs 0/57; P = .003), and more neurologic sequelae (5/12 vs 1/57; P < .001).

Conclusions

CE during therapy for DKA was associated with a drop in P_{Eff osm}. An adequate rise in P_Na may be needed to prevent this drop in P_{Eff osm}.

Abbreviations: ANOVA, Analysis of variance, CE, Cerebral edema, CT, Computed tomography, DKA, Diabetic ketoacidosis, HSC, Hospital for Sick Children, ICU, Intensive care unit, IV, Intravenous, P_{Eff osm}, Effective plasma osmolality, P_Glucose, Glucose concentration in plasma, P_Na, Sodium concentration in plasma, USP, University Hospital of São Paulo