Invasive brain tissue oxygen and intracranial pressure (ICP) monitoring versus ICP-only monitoring in pediatric severe traumatic brain injury
Authors: Lang Shih-Shan , Kumar Nankee K. , Zhao Chao , Zhang David Y. , Tucker Alexander M. , Storm Phillip B. , Heuer Gregory G. , Gajjar Avi A. , Kim Chong Tae , Yuan Ian , Sotardi Susan , Kilbaugh Todd J. , Huh Jimmy W. 
Published: June 2022

OBJECTIVE
Severe traumatic brain injury (TBI) is a leading cause of disability and death in the pediatric population. While intracranial pressure (ICP) monitoring is the gold standard in acute neurocritical care following pediatric severe TBI, brain tissue oxygen tension (PbtO2) monitoring may also help limit secondary brain injury and improve outcomes. The authors hypothesized that pediatric patients with severe TBI and ICP + PbtO2 monitoring and treatment would have better outcomes than those who underwent ICP-only monitoring and treatment.

METHODS
Patients ≤ 18 years of age with severe TBI who received ICP ± PbtO2 monitoring at a quaternary children’s hospital between 1998 and 2021 were retrospectively reviewed. The relationships between conventional measurements of TBI were evaluated, i.e., ICP, cerebral perfusion pressure (CPP), and PbtO2. Differences were analyzed between patients with ICP + PbtO2 versus ICP-only monitoring on hospital and pediatric intensive care unit (PICU) length of stay (LOS), length of intubation, Pediatric Intensity Level of Therapy scale score, and functional outcome using the Glasgow Outcome Score–Extended (GOS-E) scale at 6 months postinjury.

RESULTS
Forty-nine patients, including 19 with ICP + PbtO2 and 30 with ICP only, were analyzed. There was a weak negative association between ICP and PbtO2 (β = −0.04). Conversely, there was a strong positive correlation between CPP ≥ 40 mm Hg and PbtO2 ≥ 15 and ≥ 20 mm Hg (β = 0.30 and β = 0.29, p < 0.001, respectively). An increased number of events of cerebral PbtO2 < 15 mm Hg or < 20 mm Hg were associated with longer hospital (p = 0.01 and p = 0.022, respectively) and PICU (p = 0.015 and p = 0.007, respectively) LOS, increased duration of mechanical ventilation (p = 0.015 when PbtO2 < 15 mm Hg), and an unfavorable 6-month GOS-E score (p = 0.045 and p = 0.022, respectively). An increased number of intracranial hypertension episodes (ICP ≥ 20 mm Hg) were associated with longer hospital (p = 0.007) and PICU (p < 0.001) LOS and longer duration of mechanical ventilation (p < 0.001). Lower minimum hourly and average daily ICP values predicted favorable GOS-E scores (p < 0.001 for both). Patients with ICP + PbtO2 monitoring experienced longer PICU LOS (p = 0.018) compared to patients with ICP-only monitoring, with no significant GOS-E score difference between groups (p = 0.733).

CONCLUSIONS
An increased number of cerebral hypoxic episodes and an increased number of intracranial hypertension episodes resulted in longer hospital LOS and longer duration of mechanical ventilator support. An increased number of cerebral hypoxic episodes also correlated with less favorable functional outcomes. In contrast, lower minimum hourly and average daily ICP values, but not the number of intracranial hypertension episodes, were associated with more favorable functional outcomes. There was a weak correlation between ICP and PbtO2, supporting the importance of multimodal invasive neuromonitoring in pediatric severe TBI.