Assessing the Impact of 3% Hypertonic Saline Hyperosmolar Therapy on Intubated Children With Isolated Traumatic Brain Injury by Cerebral Oximetry in a Pediatric Emergency Setting
Authors: Washer Leigh-Ann , Abramo Thomas , Hardgrave Hailey , Harris Zena Leah , Meredith Mark , Moore Katherine , Dalabih Abudulah , Williams David , Jorgenson-Stough Amy , Crawley Lee 
Published: February 2020

Background
Intubated pediatric patients with isolated traumatic brain injury (TBI) are a diagnostic challenge for early detection of altered cerebral physiology instigated by trauma-induced increased intracranial pressure (ICP) while preventing secondary neuronal damage (secondary insult detection) and assessing the effects of increased ICP therapeutic interventions (3% hypertonic saline [HTS]). Invasive brain tissue oxygen monitoring is guiding new intensive care unit TBI management but is not pediatric emergency department (PED) readily accessible. Objective measurements on pediatric isolated TBI-altered bihemispheric cerebral physiology and treatment effects of 3% HTS are currently lacking. Cerebral oximetry can assess increased ICP-induced abnormal bihemispheric cerebral physiology by measuring regional tissue oxygenation (rcSO2) and cerebral blood volume index (CBVI) and the mechanical cerebrospinal fluid removal effects on the increased ICP-induced abnormal bihemispheric cerebral physiology.
In the PED intubated patients with isolated TBI, assessing the 3% HTS therapeutic response is solely by vital signs and limited clinical assessment skills. Objective measurements of the 3% HTS hyperosmolar effects on the PED isolated TBI patients' altered bihemispheric cerebral physiology are lacking. We believe that bihemispheric rcSO2 and CBVI could elucidate similar data on 3% HTS impact and influence in the intubated isolated TBI patients.

Objective
This study aimed to analyze the effects of 3% HTS on bihemispheric rcSO2 and CBVI in intubated patients with isolated TBI.

Methods
An observational, retrospective analysis of bihemispheric rcSO2 and CBVI readings in intubated pediatric patients with isolated TBI receiving 3% HTS infusions, was performed.

Results
From 2010 to 2017, 207 intubated patients with isolated TBI received 3% HTS infusions (median age, 2.9 [1.1–6.9 years]; preintubation Glasgow Coma Scale score, 7 [6–8]). The results were as follows: initial pre−3% HTS, 43% (39.5% to 47.5%; left) and 38% (35% to 42%; right) for rcSO2 < 60%, and 8 (−28 to 21; left) and −15 (−34 to 22; right) for CBVI; post–3% HTS, 68.5% (59.3% to 76%, P < 0.0001; left) and 62.5% (56.0% to 74.8%, P < 0.0001; right) for rcSO2 < 60%, and 12 (−7 to 24, P = 0.04; left) and 14 (−21 to 22, P < 0.0001; right) for CBVI; initial pre–3% HTS, 90% (83% to 91%; left) and 87% (82% to 92%; right) for rcSO2 > 80%, and 16.5 (6 to 33, P < 0.0001; left) and 16.8 (−2.5 to 27.5, P = 0.005; right) for CBVI; and post–3% HTS, 69% (62% to 72.5%, P < 0.0001; left) and 63% (59% to 72%, P < 0.0001; right) for rcSO2 > 80%, and 16.5 (6 to 33, P < 0.0001; left) and 16.8 (−2.5 to 27.5, P = 0.005; right) for CBVI. The following results for cerebral pathology pre–3% HTS were as follows: epidural: 85% (58% to 88.5%) for left rcSO2 and −9.25 (−34 to 19) for left CBVI, and 85.5% (57.5% to 89%) for right rcSO2 and −12.5 (−21 to 27) for CBVI; subdural: 45% (38% to 54%) for left rcSO2 and −9.5 (−25 to 19) for left CBVI, and 40% (33% to 49%) for right rcSO2 and −15 (−30.5 to 5) for CBVI. The following results for cerebral pathology post–3% HTS were as follows: epidural: 66% (58% to 69%, P = 0.03) for left rcSO2 and 15 (−1 to 21, P = 0.0004) for left CBVI, and 63% (52% to 72%, P = 0.009) for right rcSO2, and 15.5 (−22 to 24, P = 0.02) for CBVI; subdural: 63% (56% to 72%, P < 0.0001) for left rcSO2 and 9 (−20 to 22, P < 0.0001) for left CBVI, and 62.5% (48% to 73%, P < 0.0001) for right rcSO2, and 3 (−26 to 22, P < 0.0001) for CBVI. Overall, heart rate showed no significant change. Three percent HTS effect on interhemispheric rcSO2 difference >10 showed rcSO2 < 60%, and subdural hematomas had the greatest reduction (P < 0.001). The greatest positive changes occurred in bihemispheric or one-hemispheric rcSO2 < 60% with an interhemispheric discordance rcSO2 > 10 and required the greatest number of 3% HTS infusions. For 3% HTS 15% rcSO2 change time effect, all patients achieved positive change with subdural hematomas and hemispheric rcSO2 readings <60% with the shortest achievement time of 1.2 minutes (0.59–1.75; P < 0.001).

Conclusions
In intubated pediatric patients with isolated TBI who received 3% HTS infusions, bihemispheric rcSO2 and CBVI readings immediately detected and trended the 3% HTS effects on the trauma-induced cerebral pathophysiology. The 3% HTS infusion produced a significant improvement in rcSO2 and CBVI readings and a reduction in interhemispheric rcSO2 discordance differences. In patients with bihemispheric or one-hemispheric rcSO2 readings <60% with or without an interhemispheric discordance, rcSO2 > 10 demonstrated the greatest significant positive delta change and required the greatest numbers of 3% HTS infusions. Overall, 3% HTS produced a significant positive 15% change within 2.1 minutes of infusion, whereas heart rate showed no significant change. During trauma neuroresuscitation, especially in intubated isolated TBI patients requiring 3% HTS, cerebral oximetry has shown its functionality as a rapid adjunct neurological, therapeutic assessment tool and should be considered in the initial emergency department pediatric trauma neurological assessment and neuroresuscitation regimen.