Invasive Intracranial Pressure Monitoring for Pediatric Traumatic Brain Injury: Do Data Support Dogma?

Secondary brain injury following trauma is an important cause of neurological injury occurring after the primary insult. Elevated intracranial pressure (ICP) is one of the key mechanisms responsible for secondary injury in traumatic brain injury (TBI). The 2019 update of Pediatric Brain Trauma Foundation (BTF) guideline gives a level three recommendation for using ICP monitors to improve overall outcomes [1, 2]. While invasive ICP monitoring assists in goal-directed management, targeting a specific number without clinical context has faced criticism, with some centers using clinical and imaging parameters to guide therapy without any significant difference in outcome [3]. One fundamental consideration is the use of purely Glasgow Coma Scale (GCS)-based classification of TBI in children, which then drives subsequent management algorithm. Appavu et al. [3] argue that GCS-based classification of TBI in children does not fully capture the intricacies of varied TBI presentations in children. Manley et al. [4] recently proposed the CBI-M classification of TBI as part of the NIH-NINDS TBI classification and nomenclature initiative, incorporating clinical, blood biomarkers, imaging and patient specific modifiers. However, application and utility of this classification system in the pediatric TBI population remains to be seen.The BTF Guideline examined three studies providing direct evidence for ICP monitoring in severe TBI and 16 studies that provided indirect evidence by examining the role of elevated ICP in the outcome of pediatric TBI. Alkhoury and Kyriakides [5] analyzed the US National Trauma Data Bank (NTDB) for patients <17 years who had TBI with GCS ≤8, finding no survival advantage with ICP monitoring despite longer hospital and intensive care unit (ICU) stays, more ventilator and monitored days. Further subgroup analysis indicated survival benefit only for patients with GCS 3, not in other GCS groups. Another retrospective review using hospitals as units had interrogated the Pediatric Health Information System (PHIS) database to identify children <18 years with a diagnosis of severe TBI with and without ICP monitoring [6]. Hospitals with higher standardized ICP monitoring rates and hospitals with higher patient volumes had better outcomes. However, the authors cautioned that a causal relationship between ICP monitoring and improvement in outcomes cannot be inferred from the type of analysis conducted.Bennett et al. [7] combined data from NTDB and PHIS databases in a retrospective propensity score-based analysis involving 3,084 patients (1,002 monitored, 2,082 unmonitored). There was no significant difference in the functional outcome between patients who underwent ICP compared to patients without ICP monitoring. Further subgroup analysis showed that although ICP monitoring was not associated with in-hospital mortality, it was significantly associated with a higher likelihood of overall mortality, discharge to hospice, or either tracheostomy or gastrostomy placement.Chestnut et al. [8] conducted a multicenter prospective randomized controlled trial (BEST:TRIP) to examine if the use of ICP monitoring in severe TBI leads to improved outcomes compared to no invasive ICP monitoring, providing level I evidence. There were no significant differences in the 14-day mortality, 6-month mortality, or the composite primary outcome between the ICP monitored group and non-monitored group. Conducted in Bolivia and Ecuador, the trial’s generalizability has been questioned due to limited pre-hospital resources, although in-hospital randomization remains valid.In a recent meta-analysis summarizing the evidence on the use of ICP monitoring in pediatric patients with severe TBI, Xue et al. [9] did not find any significant difference in mortality between the ICP monitored group compared to non-monitored group. However, studies utilizing propensity score matching demonstrated a mortality reduction (OR 0.62, patient event rate 55/471). From these data, we estimated a number needed to treat (NNT) of 25, that is, one death averted in every 25 patients who underwent ICP monitoring. Xue et al. [9] also provide data about associated complications, but it is difficult to determine if the complications can be ascribed to ICP monitoring or they are due to TBI itself. One of the outcomes of interest is the length of ICU stay, where ICP monitoring was associated with a significantly prolonged hospital stay (mean difference of 7.82 days, 95% C.I 4.17–11.46).Given the ambiguity in evidence for this very important aspect of pediatric TBI, a robust randomized controlled trial is the need of the hour. The Benchmark Evidence Led by Latin America: Trial of Intracranial Pressure-Pediatrics (BELA TRIPP) seeks to address this and is currently recruiting participants [10]. It is a multicenter, randomized superiority trial, intended to provide class I evidence regarding the use of ICP monitoring in pediatric TBI. They have also published the management protocol in the two treatment groups as suggested management algorithms for pediatric severe TBI [11]. We do note that it suggests scheduled hyperosmolar therapy, adapted from the CREVICE protocol [11, 12]. Apart from quality of life and mortality outcomes, BELA TRIPP trial will also examine the length of ICU stay and number of neurosurgical interventions performed in each group, giving us an idea if ICP monitoring is associated with increased interventions and if it provides a survival advantage. The trial is expected to be completed by December 2026.Literature shows that increased ICP is related to worse outcomes in TBI and lowering ICP improves outcome, providing indirect evidence for the BTF recommendation of ICP monitoring in severe TBI [13, 14]. However, the single randomized trial conducted in adults assessing effect of invasive ICP monitoring did not find any significant difference in outcome, likely because clinical deterioration may occur even with a normal ICP or raised ICP which is clinically relevant manifested itself and was treated [8]. While elevated ICP in severe TBI is associated with poor outcome and lower ICP is associated with better outcome, it is a separate question if invasive ICP monitoring translates to an improvement in outcome. The available literature currently does not show clear evidence favoring standardized invasive ICP monitoring for all patients with significant TBI which the BELA TRIPP trial seeks to address by providing class I evidence. Identifying which patients may benefit from placement of an ICP monitor remains paramount as the consequences of severe head injury are significant. This is more so for multimodal monitoring, where management decisions may be influenced by information obtained from other modalities, and the relevance of incremental information gain from invasive ICP monitoring in the setting of maximum medical/surgical management can be debatable.The authors do not have any conflicts of interest to disclose.The authors did not receive any funding for the present study.Debajyoti Datta – conceptualization, data curation and analysis, and writing – original draft preparation. Albert Tu – conceptualization, writing – review and editing, and supervision.