Testing the Impact of Protocolized Care of Patients With Severe Traumatic Brain Injury Without Intracranial Pressure Monitoring: The Imaging and Clinical Examination Protocol

Exploration of the relationship between partial pressure of brain tissue oxygen and intracranial pressure

Introduction

Partial pressure of brain tissue oxygen (PbtO2) has been shown to be a safe an effective monitoring modality to compliment intracranial pressure (ICP) monitoring. It is related to metabolic activity, disease severity and mortality.

Research question

Understanding the complex relationship between PbtO2 and ICP for patients with traumatic brain injury will enable better clinical decision making beyond simple threshold treatment strategies.

Material and methods

Patients with PbtO2 monitoring were identified from the BrainIT database, a multi-centre dataset, containing minute by minute PbtO2 and ICP readings. Missing data was imputed and a multi-level log-normal regression model with a compound symmetry correlation structure was built. This accounted for any increased correlation due to the repeated measurements. The model was adjusted for mean arterial pressure and the partial pressure of carbon dioxide. Non-linearity was assessed using analysis of deviance and trends using expected marginal means.

Results

11 subjects with over 82,000 readings were included. They had a median age of 38 (IQR: 37-47), 73% were male, a median length of stay of 11.8 (IQR: 6.6-19.7) days and a median extended Glasgow outcome scale of 7.00 (IQR: 5-8).There is a statistically significant (p < 0.001) non-linear effect of ICP on PbtO2. With an overall increase in PbtO2 of 5.2% (95% CI 4%-6.4%, p < 0.001) for a 10 mmHg increase in ICP below 22 mmHg and a decrease of 5.5% (95% CI 2.7%-8.3%, p=<0.001) in PbtO2 for a 10 mmHg increase in ICP above 22 mmHg. As well as a decrease of 40.9% (95% CI 2.3%-64.3%, p = 0.040) in PbtO2 per day in the intensive care unit.

Discussion and conclusion

This model demonstrates that there is a significant non-linear relationship between ICP and PbtO2, however, this is a small heterogeneous cohort and further validation will be required.

Traumatic Brain Injury and Traumatic Spinal Cord Injury

OBJECTIVE

This article reviews the mechanisms of primary traumatic injury to the brain and spinal cord, with an emphasis on grading severity, identifying surgical indications, anticipating complications, and managing secondary injury.

LATEST DEVELOPMENTS

Serum biomarkers have emerged for clinical decision making and prognosis after traumatic injury. Cortical spreading depolarization has been identified as a potentially modifiable mechanism of secondary injury after traumatic brain injury. Innovative methods to detect covert consciousness may inform prognosis and enrich future studies of coma recovery. The time-sensitive nature of spinal decompression is being elucidated.

ESSENTIAL POINTS

Proven management strategies for patients with severe neurotrauma in the intensive care unit include surgical decompression when appropriate, the optimization of perfusion, and the anticipation and treatment of complications. Despite validated models, predicting outcomes after traumatic brain injury remains challenging, requiring prognostic humility and a model of shared decision making with surrogate decision makers to establish care goals. Penetrating injuries, especially gunshot wounds, are often devastating and require public health and policy approaches that target prevention.

Development of a Randomized Trial Comparing ICP-Monitor-Based Management of Severe Pediatric Traumatic Brain Injury to Management Based on Imaging and Clinical Examination Without ICP Monitoring-Research Algorithms

BACKGROUND AND OBJECTIVES

The efficacy of our current approach to incorporating intracranial pressure (ICP) data into pediatric severe traumatic brain injury (sTBI) management is incompletely understood, lacking data from multicenter, prospective, randomized studies. The National Institutes of Health-supported Benchmark Evidence from Latin America-Treatment of Raised Intracranial Pressure-Pediatrics trial will compare outcomes from pediatric sTBI of a management protocol based on ICP monitoring vs 1 based on imaging and clinical examination without monitoring. Because no applicable comprehensive management algorithms for either cohort are available, it was necessary to develop them.

METHODS

A consensus conference involving the 21 intensivists and neurosurgeons from the 8 trial sites used Delphi-based methodology to formulate management algorithms for both study cohorts. We included recommendations from the latest Brain Trauma Foundation pediatric sTBI guidelines and the consensus-based adult algorithms (Seattle International Brain Injury Consensus Conference/Consensus Revised Imaging and Clinical Examination) wherever relevant. We used a consensus threshold of 80%.

RESULTS

We developed comprehensive management algorithms for monitored and nonmonitored cohort children with sTBI. We defined suspected intracranial hypertension for the nonmonitored group, set minimum number and timing of computed tomography scans, specified minimal age-adjusted mean arterial pressure and cerebral perfusion pressure targets, defined clinical neuroworsening, described minimal requisites for intensive care unit management, produced tiered management algorithms for both groups, and listed treatments not routinely used.

CONCLUSION

We will study these protocols in the Benchmark Evidence from Latin America-Treatment of Raised Intracranial Pressure-Pediatrics trial in low- and middle-income countries. Second, we present them here for consideration as prototype pediatric sTBI management algorithms in the absence of published alternatives, acknowledging their limited evidentiary status. Therefore, herein, we describe our study design only, not recommended treatment protocols.

The Roles of Protocols and Protocolization in Improving Outcome From Severe Traumatic Brain Injury

BACKGROUND AND OBJECTIVES

Our Phase-I parallel-cohort study suggested that managing severe traumatic brain injury (sTBI) in the absence of intracranial pressure (ICP) monitoring using an ad hoc Imaging and Clinical Examination (ICE) treatment protocol was associated with superior outcome vs nonprotocolized management but could not differentiate the influence of protocolization from that of the specific protocol. Phase II investigates whether adopting the Consensus REVised Imaging and Clinical Examination (CREVICE) protocol improved outcome directly or indirectly via protocolization.

METHODS

We performed a Phase-II sequential parallel-cohort study examining adoption of the CREVICE protocol from no protocol vs a previous protocol in patients with sTBI older than 13 years presenting ≤24 hours after injury. Primary outcome was prespecified 6-month recovery. The study was done mostly at public South American centers managing sTBI without ICP monitoring. Fourteen Phase-I nonprotocol centers and 5 Phase-I protocol centers adopted CREVICE. Data were analyzed using generalized estimating equation regression adjusting for demographic imbalances.

RESULTS

A total of 501 patients (86% male, mean age 35.4 years) enrolled; 81% had 6 months of follow-up. Adopting CREVICE from no protocol was associated with significantly superior results for overall 6-month extended Glasgow Outcome Score (GOSE) (protocol effect = 0.53 [0.11, 0.95], P = .013), mortality (36% vs 21%, HR = 0.59 [0.46, 0.76], P < .001), and orientation (Galveston Orientation and Amnesia Test discharge protocol effect = 10.9 [6.0, 15.8], P < .001, 6-month protocol effect = 11.4 [4.1, 18.6], P < .005). Adopting CREVICE from ICE was associated with significant benefits to GOSE (protocol effect = 0.51 [0.04, 0.98], P = .033), 6-month mortality (25% vs 18%, HR = 0.55 [0.39, 0.77], P < .001), and orientation (Galveston Orientation and Amnesia Test 6-month protocol effect = 9.2 [3.6, 14.7], P = .004). Comparing both groups using CREVICE, those who had used ICE previously had significantly better GOSE (protocol effect = 1.15 [0.09, 2.20], P = .033).

CONCLUSION

Centers managing adult sTBI without ICP monitoring should strongly consider protocolization through adopting/adapting the CREVICE protocol. Protocolization is indirectly supported at sTBI centers regardless of resource availability.