Bihemispheric Cerebral Oximetry Monitoring's Functionality in Suspected Cerebral Edema Diabetic Ketoacidosis With Therapeutic 3% Hyperosmolar Therapy in a Pediatric Emergency Department
Authors: Abramo Thomas J. , Szlam Sarah , Hargrave Hailey , Harris Zena Leah , Williams Abby , Meredith Mark , Hedrick Madison , Hu Zhuopei , Nick Todd , Gonzalez Cruz Velasco 
Published: April 2019

Background
Suspected cerebral edema diabetic ketoacidosis (SCEDKA) is more common than perceived with symptoms including altered mentation, headache with vomiting, depressed Glasgow coma scale (GCS), abnormal motor or verbal responses, combativeness, and neurological depression. Suspected cerebral edema diabetic ketoacidosis has been associated with initial diabetic ketoacidosis (DKA) presentation and at start of DKA therapy.
Cerebral oximetry (bihemispheric regional cerebral oxygen saturation [rcSO2] and cerebral blood volume index [CBVI]) can detect increased intracranial pressure (ICP)–induced altered bihemispheric cerebral physiology (rcSO2) (Crit Care Med 2006;34:2217–2223, J Pediatr 2013;163: 1111–1116, Curr Med Chem 2009;16:94–112, Diabetologia 1985;28:739–742, Pediatr Crit Care Med 2013;14:694–700). In pediatrics, rcSO2 of less than 60% or rcSO2 of greater than 85% reflects increased ICP and cerebral edema (Crit Care Med 2006;34:2217–2223, J Pediatr 2013;163: 1111–1116, Curr Med Chem 2009;16:94–112, Diabetologia 1985;28:739–742, Pediatr Crit Care Med 2013;14:694–700). Cerebral oximetry can detect increased ICP–induced altered bihemispheric cerebral physiology (rcSO2, CBVI) and cerebral physiological changes (rcSO2, CBVI changes) during therapeutic mechanical cerebral spinal fluid removal to decrease increased ICP (Crit Care Med 2006;34:2217–2223, J Pediatr 2013;163: 1111–1116, Curr Med Chem 2009;16:94–112, Diabetologia 1985;28:739–742, Pediatr Crit Care Med 2013;14:694–700).
In the pediatric intensive care units, SCEDKA patients with nonbihemispheric cerebral oximetry showed an initial rcSO2 of greater than 90%. Bihemispheric rcSO2 with CBVI in SCEDKA patients has the potential to detect the abnormal cerebral physiology and disruptive autoregulation while detecting 3% hypertonic saline solution (HTS) effects on the SCEDKA altered cerebral physiology (rcSO2).

Purpose
The purposes of this study were to analyze and compare 3% HTS effect on bihemispheric rcSO2 readings, neurological and biochemical parameters in SCEDKA with 3% HTS infusion to non-SCEDKA patients in pediatric emergency department (PED).

Methods
An observational retrospective comparative analysis study of bihemispheric rcSO2 readings, neurological and biochemical parameters in 2 groups of PED DKA patients were performed: PED DKA patients with SCEDKA +3% HTS infusions versus non-SCEDKA without 3% HTS infusions.

Results
From 2008 to 2013, of the 1899 PED DKA patients, 60 SCEDKA patients received 3% HTS (5 mL/kg via peripheral intravenous) infusion (median age of 5 years [range, 3.7–7 years]), with 42 new DKA insulin dependent diabetes mellitus onset. Suspected cerebral edema diabetic ketoacidosis patients had GCS of 11 (range, 11–12), with consistent SCEDKA signs and symptoms (severe headaches with vomiting, confusion, blurred vision, altered speech, lethargy, and combativeness). Suspected cerebral edema diabetic ketoacidosis patients' initial (0–5 minutes) left rcSO2 readings were 91.4% (range, 88.4%–94.1%) and right was 90.3% (range, 88.6%–94.1%) compared with non-SCEDKA patients' left rcSO2 readings of 73.2% (range, 69.7%–77.8%) and right of 73.2% (range, 67.6%–77%) (P < 0.0001). The rcSO2 monitoring time before 3% HTS infusion was 54.9 minutes (range, 48.3–66.8 minutes) with 3% HTS time effect change: pre–3% HTS (54.9 minutes [range, 48.3–66.8 minutes]). Before 3% HTS infusion, the left rcSO2 readings were 90.0% (range, 89%–95%) and right was 91% (range, 86%–95%). The 30 to 45 minutes post–3% HTS showed that left was 64% (range, 62%–69%) and right was 65.4% (range, 63%–70%) (P < 0.0001). rcSO2 Δ change for post–3% HTS (0–20 minutes) to pre–3% HTS was as follows: left, −26.58 (−29.5 to −23.7) (P < 0.0001); right, −25.2 (−27.7 to −22.6) (P < 0.0001). Post–3% HTS GCS (14,15) and biochemistry compared with pre–3% HTS infusions all improved (P < 0.001).

Conclusions
In PED SCEDKA patients, the pre–3% HTS bihemispheric rcSO2 readings were greater than 90% and had lower GCS than non-SCEDKA patients. The post–3% HTS infusion rcSO2 readings showed within minutes a substantial reduction compared with non-SCEDKA patients, with no complications. Changes in rcSO2 readings after 3% HTS correlated with improved SCEDKA indicators (improved mental status, headache, and GCS) without any complications. We showed that cerebral oximetry in PED SCEDKA patients has shown an initial bihemispheric of greater than 90% readings signifying abnormal bihemispheric cerebral physiology. We also showed the cerebral oximetry's functionality in detecting 3% HTS therapeutic effects on SCEDKA's abnormal cerebral physiology and the beneficial therapeutic effects of 3% HTS infusion in SCEDKA patients. Using cerebral oximetry in pediatric DKA patients' initial cerebral assessment could have a significant impact in detecting SCEDKA patients. Further SCEDKA research using cerebral oximetry should be considered.