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 (PEff osm ; 2 × plasma sodium [PNa ] + 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 PEff 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 PEff osm from 304 ± 5 to 290 ± 5 mOsm/kg ( P < .001). Control patients did not show this drop in PEff osm at 4 hours (1 ± 2 and 2 ± 2 vs –9 ± 2 mOsm/kg; P < .01), because of a larger rise in PNa 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 PEff osm . An adequate rise in PNa may be needed to prevent this drop in PEff osm.