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Position of probe determines prognostic information of brain tissue PO2 in severe traumatic brain injury.

ABSTRACT: Monitoring brain tissue PO2 (PbtO2) is part of multimodality monitoring of patients with traumatic brain injury (TBI). However, PbtO2 measurement is a sampling of only a small area of tissue surrounding the sensor tip.To examine the effect of catheter location on the relationship between PbtO2 and neurological outcome.A total of 405 patients who had PbtO2 monitoring as part of standard management of severe traumatic brain injury were studied. The relationships between probe location and resulting PbtO2 and outcome were examined.When the probe was located in normal brain, PbtO2 averaged 30.8 ± 18.2 compared with 25.6 ± 14.8 mm Hg when placed in abnormal brain (P < .001). Factors related to neurological outcome in the best-fit logistic regression model were age, PbtO2 probe position, postresuscitation motor Glasgow Coma Scale score, and PbtO2 trend pattern. Although average PbtO2 was significantly related to outcome in univariate analyses, it was not significant in the final logistic model. However, the interaction between PbtO2 and probe position was statistically significant. When the PbtO2 probe was placed in abnormal brain, the average PbtO2 was higher in those with a favorable outcome, 28.8 ± 12.0 mm Hg, compared with those with an unfavorable outcome, 19.5 ± 13.7 mm Hg (P = .01). PbtO2 and outcome were not related when the probe was placed in normal-appearing brain.These results suggest that the location of the PbtO2 probe determines the PbtO2 values and the relationship of PbtO2 to neurological outcome.

SUBMITTER: Ponce LL

PROVIDER: S-EPMC3954543 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature

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Position of probe determines prognostic information of brain tissue PO2 in severe traumatic brain injury.

Ponce Lucido L LL Pillai Shibu S Cruz Jovany J Li Xiaoqi X Julia H H Gopinath Shankar S Robertson Claudia S CS

Neurosurgery 20120601 6

<h4>Background</h4>Monitoring brain tissue PO2 (PbtO2) is part of multimodality monitoring of patients with traumatic brain injury (TBI). However, PbtO2 measurement is a sampling of only a small area of tissue surrounding the sensor tip.<h4>Objective</h4>To examine the effect of catheter location on the relationship between PbtO2 and neurological outcome.<h4>Methods</h4>A total of 405 patients who had PbtO2 monitoring as part of standard management of severe traumatic brain injury were studied. ...[more]

PMID: 22289784

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Project description:Importance:Advances in treatment of traumatic brain injury are hindered by the inability to monitor pathological mechanisms in individual patients for targeted neuroprotective treatment. Spreading depolarizations, a mechanism of lesion development in animal models, are a novel candidate for clinical monitoring in patients with brain trauma who need surgery. Objective:To test the null hypothesis that spreading depolarizations are not associated with worse neurologic outcomes. Design, Setting, and Participants:This prospective, observational, multicenter cohort study was conducted from February 2009 to August 2013 in 5 level 1 trauma centers. Consecutive patients who required neurological surgery for treatment of acute brain trauma and for whom research consent could be obtained were enrolled; participants were excluded because of technical problems in data quality, patient withdrawal, or loss to follow-up. Primary statistical analysis took place from April to December 2018. Evaluators of outcome assessments were blinded to other measures. Interventions:A 6-contact electrode strip was placed on the brain surface during surgery for continuous electrocorticography during intensive care. Main Outcomes and Measures:Electrocorticography was scored for depolarizations, following international consensus procedures. Six-month outcomes were assessed by the Glasgow Outcome Scale-Extended score. Results:A total of 157 patients were initially enrolled; 19 were subsequently excluded. The 138 remaining patients (104 men [75%]; median [interquartile range] age, 45 [29-64] years) underwent a median (interquartile range) of 75.5 (42.2-117.1) hours of electrocorticography. A total of 2837 spreading depolarizations occurred in 83 of 138 patients (60.1% incidence) who, compared with patients who did not have spreading depolarizations, had lower prehospital systolic blood pressure levels (mean [SD], 133 [31] mm Hg vs 146 [33] mm Hg; P?=?.03), more traumatic subarachnoid hemorrhage (depolarization incidences of 17 of 37 [46%], 18 of 32 [56%], 22 of 33 [67%], and 23 of 30 patients [77%] for Morris-Marshall Grades 0, 1, 2, and 3/4, respectively; P?=?.047), and worse radiographic pathology (in 38 of 73 patients [52%] and 42 of 60 patients [70%] for Rotterdam Scores 2-4 vs 5-6, respectively; P?=?.04). Of patients with depolarizations, 32 of 83 (39%) had only sporadic events that induced cortical spreading depression of spontaneous electrical activity, whereas 51 of 83 patients (61%) exhibited temporal clusters of depolarizations (?3 in a 2-hour span). Nearly half of those with clusters (23 of 51 [45%]) also had depolarizations in an electrically silent area of the cortex (isoelectric spreading depolarization). Patients with clusters did not improve in motor neurologic examinations from presurgery to postelectrocorticography, while other patients did improve. In multivariate ordinal regression adjusting for baseline prognostic variables, the occurrence of depolarization clusters had an odds ratio of 2.29 (95% CI, 1.13-4.65; P?=?.02) for worse outcomes. Conclusions and Relevance:In this cohort study of patients with acute brain trauma, spreading depolarizations were predominant but heterogeneous and independently associated with poor neurologic recovery. Monitoring the occurrence of spreading depolarizations may identify patients most likely to benefit from targeted management strategies.

Project description:BackgroundBrain tissue hypoxia is an independent risk factor for unfavorable outcomes in traumatic brain injury (TBI); however, systemic hyperoxemia encountered in the prevention and/or response to brain tissue hypoxia may also impact risk of mortality. We aimed to identify temporal patterns of partial pressure of oxygen in brain tissue (PbtO2), partial pressure of arterial oxygen (PaO2), and PbtO2/PaO2 ratio associated with mortality in children with severe TBI.MethodsData were extracted from the electronic medical record of a quaternary care children's hospital with a level I trauma center for patients ≤ 18 years old with severe TBI and the presence of PbtO2 and/or intracranial pressure monitors. Temporal analyses were performed for the first 5 days of hospitalization by using locally estimated scatterplot smoothing for less than 1,000 observations and generalized additive models with integrated smoothness estimation for more than 1,000 observations.ResultsA total of 138 intracranial pressure-monitored patients with TBI (median 5.0 [1.9-12.8] years; 65% boys; admission Glasgow Coma Scale score 4 [3-7]; mortality 18%), 71 with PbtO2 monitors and 67 without PbtO2 monitors were included. Distinct patterns in PbtO2, PaO2, and PbtO2/PaO2 were evident between survivors and nonsurvivors over the first 5 days of hospitalization. Time-series analyses showed lower PbtO2 values on day 1 and days 3-5 and lower PbtO2/PaO2 ratios on days 1, 2, and 5 among patients who died. Analysis of receiver operating characteristics curves using Youden's index identified a PbtO2 of 30 mm Hg and a PbtO2/PaO2 ratio of 0.12 as the cut points for discriminating between survivors and nonsurvivors. Univariate logistic regression identified PbtO2 < 30 mm Hg, hyperoxemia (PaO2 ≥ 300 mm Hg), and PbtO2/PaO2 ratio < 0.12 to be independently associated with mortality.ConclusionsLower PbtO2, higher PaO2, and lower PbtO2/PaO2 ratio, consistent with impaired oxygen diffusion into brain tissue, were associated with mortality in this cohort of children with severe TBI. These results corroborate our prior work that suggests targeting a higher PbtO2 threshold than recommended in current guidelines and highlight the potential use of the PbtO2/PaO2 ratio in the management of severe pediatric TBI.

Project description:Purpose: Post-traumatic epilepsy (PTE) is an epilepsy that develops after traumatic brain injury (TBI), and it comprises 10-20% of structural epilepsies and 5% of all epilepsies. The lack of prognostic biomarkers for PTE hinders the development of anti-epileptogenic treatments. In this preclinical multicenter study, plasma samples collected from a rat model of PTE were analyzed by small RNA sequencing to reveal the post-TBI expression profile of circulating microRNAs and to identify potential miRNA biomarkers for PTE development. Methods: The animal experiments were conducted at 3 different study sites: University of Eastern Finland (Finland), Monash University (Australia), and University of California, Los Angeles (USA). Severe TBI was induced in adult male Sprague-Dawley rats by the lateral fluid-percussion injury (LFPI) method. Rats that developed PTE were identified by video-EEG monitoring during the 7th post-injury month (TBI rats with epilepsy, TBIE; TBI rats without epilepsy, TBIN). Small RNA sequencing was conducted with plasma samples collected 48 hours after TBI or sham operation (craniotomy). Following the primary quantification, DESeq2 (v. 1.42.0) was used to identify differentially expressed miRNAs between the experiment groups. Results were further validated in a larger sample cohort by droplet digital PCR (ddPCR). Results: Small RNA sequencing detected a total of 754 miRNAs that were expressed in at least one sample. DESeq2 detected 23 differentially expressed (DE) miRNAs between the TBI and sham groups, 12 between the TBIE and sham groups, and 5 between the TBIN and sham groups. In contrast, no DE miRNAs were detected between the TBIE and TBIN groups. From the list of 23 DE miRNAs between the TBI and sham groups, 3 upregulated miRNAs (rno-miR-183-5p, rno-miR-323-3p, and miR-434-3p) were selected for further ddPCR validation. The list of miRNAs for validation was further complemented by 4 miRNAs (rno-miR-9a-3p, rno-miR-124-3p, rno-miR-132-3p, and rno-miR-212-3p), which were not differentially expressed in the DESeq2 analysis, but which we have previously detected to be acutely upregulated in TBI rat plasma. The validation was conducted with samples from the entire EpiBioS4Rx cohort [26 baseline samples, 45 sham, 164 TBI (32 TBIE, 132 TBIN)]. DdPCR analysis revealed that all 7 investigated miRNAs were upregulated in the TBI rats compared with the sham controls. No differences were detected between the rats with (TBIE) or without epilepsy (TBIN). In contrast, TBIE rats that had seizure clusters (severe PTE) had lower levels of plasma miR-212-3p compared with other TBI rats. Furthermore, elastic net regularized logistic regression (glmnet) analysis identified miR-212-3p and miR-132-3p as the optimal set to differentiate TBIE rats with seizure clusters from other TBI rats. Conclusions: The profile of circulating plasma microRNAs differed between TBI rats and sham controls. MiR-212-3p alone or in combination with miR-132-3p showed potential as prognostic biomarkers for development of severe PTE.

Project description:BackgroundThis study is a substudy of a prospective consecutive double-blinded randomized study on the effect of prostacyclin in severe traumatic brain injury (sTBI). The aims of the present study were to investigate whether there was a correlation between brain and subcutaneous glycerol levels and whether the ratio of interstitial glycerol in the brain and subcutaneous tissue (glycerolbrain/sc) was associated with tissue damage in the brain, measured by using the Rotterdam score, S-100B, neuron-specific enolase (NSE), the Injury Severity Score (ISS), the Acute Physiology and Chronic Health Evaluation Score (APACHE II), and trauma type. A potential association with clinical outcome was explored.MethodsPatients with sTBI aged 15-70 years presenting with a Glasgow Coma Scale Score ≤ 8 were included. Brain and subcutaneous adipose tissue glycerol levels were measured through microdialysis in 48 patients, of whom 42 had complete data for analysis. Brain tissue damage was also evaluated by using the Rotterdam classification of brain computed tomography scans and the biochemical biomarkers S-100B and NSE.ResultsIn 60% of the patients, a positive relationship in glycerolbrain/sc was observed. Patients with a positive correlation of glycerolbrain/sc had slightly higher brain glycerol levels compared with the group with a negative correlation. There was no significant association between the computed tomography Rotterdam score and glycerolbrain/sc. S-100B and NSE were associated with the profile of glycerolbrain/sc. Our results cannot be explained by the general severity of the trauma as measured by using the Injury Severity Score or Acute Physiology and Chronic Health Evaluation Score.ConclusionsWe have shown that peripheral glycerol may flux into the brain. This effect is associated with worse brain tissue damage. This flux complicates the interpretation of brain interstitial glycerol levels. We remind the clinicians that a damaged blood-brain barrier, as seen in sTBI, may alter the concentrations of various substances, including glycerol in the brain. Awareness of this is important in the interpretation of the data bedside as well in research.

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Position of probe determines prognostic information of brain tissue PO2 in severe traumatic brain injury.

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Position of probe determines prognostic information of brain tissue PO2 in severe traumatic brain injury.

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