Robotic Semi-Automated Transcranial Doppler Assessment of Cerebrovascular Autoregulation in Post-Concussion Syndrome: Methodological Considerations (original) (raw)
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Journal of Neurotrauma, 2003
A moving correlation index (Mx-CPP) of cerebral perfusion pressure (CPP) and mean middle cerebral artery blood flow velocity (CBFV) allows continuous monitoring of dynamic cerebral autoregulation (CA) in patients with severe traumatic brain injury (TBI). In this study we validated Mx-CPP for TBI, examined its prognostic relevance, and assessed its relationship with arterial blood pressure (ABP), CPP, intracranial pressure (ICP), and CBFV. We tested whether using ABP instead of CPP for Mx calculation (Mx-ABP) produces similar results. Mx was calculated for each hemisphere in 37 TBI patients during the first 5 days of treatment. All patients received sedation and analgesia. CPP and bilateral CBFV were recorded, and GOS was estimated at discharge. Both Mx indices were calculated from 10,000 data points sampled at 57.4Hz. Mx-CPP. 0.3 indicates impaired CA; in these patients CPP had a significant positive correlation with CBFV, confirming failure of CA, while in those with Mx , 0.3, CPP was not correlated with CBFV, indicating intact CA. These findings were confirmed for Mx-ABP. We found a significant correlation between impaired CA, indicated by Mx-CPP and Mx-ABP, and poor outcome for TBI patients. ABP, CPP, ICP, and CBFV were not correlated with CA but it must be noted that our average CPP was considerably higher than in other studies. This study confirms the validity of this index to demonstrate CA preservation or failure in TBI. This index is also valid if ABP is used instead of CPP, which eliminates the need for invasive ICP measurements for CA assessment. An unfavorable outcome is associated with early CA failure. Further studies using the Mx-ABP will reveal whether CA improves along with patients' clinical improvement.
Acta Neurochirurgica
Background Monitoring cerebrovascular reactivity in adult traumatic brain injury (TBI) has been linked to global patient outcome. Three intra-cranial pressure (ICP)-derived indices have been described. It is unknown which index is superior for outcome association in TBI outside previous single-center evaluations. The goal of this study is to evaluate indices for 6-to 12month outcome association using uniform data harvested in multiple centers. Methods Using the prospectively collected data from the Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) study, the following indices of cerebrovascular reactivity were derived: PRx (correlation between ICP and mean arterial pressure (MAP)), PAx (correlation between pulse amplitude of ICP (AMP) and MAP), and RAC (correlation between AMP and cerebral perfusion pressure (CPP)). Univariate logistic regression models were created to assess the association between vascular reactivity indices with global dichotomized outcome at 6 to 12 months, as assessed by Glasgow Outcome Score-Extended (GOSE). Models were compared via area under the receiver operating curve (AUC) and Delong's test. Results Two separate patient groups from this cohort were assessed: the total population with available data (n = 204) and only those without decompressive craniectomy (n = 159), with identical results. PRx, PAx, and RAC perform similar in outcome association for both dichotomized outcomes, alive/dead and favorable/unfavorable, with RAC trending towards higher AUC values. There were statistically higher mean values for the index, % time above threshold, and hourly dose above threshold for each of PRx, PAx, and RAC in those patients with poor outcomes. Conclusions PRx, PAx, and RAC appear similar in their associations with 6-to 12-month outcome in moderate/severe adult TBI, with RAC showing tendency to achieve stronger associations. Further work is required to determine the role for each of these cerebrovascular indices in monitoring of TBI patients.
Introduction: Traumatic brain injury (TBI) has been increasing with greater incidence. It remains a leading cause of death. Cerebral pressure autoregulation impairment is a well-known pathology after TBI that worsens the prognosis and outcome. Transcranial Doppler (TCD) can be used to assess Transient Hyperaemic response ratio (THRR) after carotid compression which is a well demonstrated valid index for cerebral autoregulation. A relative increase in mean flow velocity (MFV) of middle cerebral artery (MCA) above the baseline following the release of carotid compression denotes preserved autoregulation and sequentially predicts good outcome, whereas absence of such response indicates altered autoregulation with poor outcome. Design: Observational prospective cohort study Setting: Alexandria Main University Hospital, Department of Critical Care Medicine Patients & Methods: 120 patients with moderate or severe TBI according to Glasgow Coma Score (GCS) underwent daily TCD for 5 days post trauma. The primary end point is the Glasgow outcome score (GOS) as a measure of outcome to assess THRR after carotid compression as an indicator of cerebral pressure autoregulation as a predictor of GOS as well as a being prognostic tool. Other measures of TCD as MFV of MCA and Pulstility Index (PI) were also used as predictors of GOS and correlated with THRR. The length of stay as well as mortality were recorded and correlated to THRR. Results: There was a significant correlation between THRR and GOS (patients with THRR ≥ 1 had favorable outcome). There was also significant correlation between THRR and length of stay and mortality. Also significant correlation between THRR and MFV as well as PI was found. Conclusion: THRR provides a clinically useful index of cerebral autoregulation. THRR after carotid compression is a good predictor of GOS as well as being a prognostic tool in patients with moderate and severe TBI.
Acta Neurochirurgica, 2020
Background Pressure reactivity index (PRx) has emerged as a means to continuously monitor cerebrovascular reactivity in traumatic brain injury (TBI). However, other intracranial pressure (ICP)-based continuous metrics exist, and may have advantages over PRx. The goal of this study was to perform a scoping overview of the literature on non-PRx ICP-based continuous cerebrovascular reactivity metrics in adult TBI. Methods We searched MEDLINE, BIOSIS, EMBASE, Global Health, SCOPUS, and Cochrane Library from inception to December 2019. Using a two-stage filtering of title/abstract, and then full manuscript, we identified pertinent articles. Data was abstracted to tables and each technique summarized, including pulse amplitude index (PAx), correlation between pulse amplitude of ICP and cerebral perfusion pressure (RAC), PRx 55-15 , and low-resolution metrics LAx and L-PRx. Results A total of 23 articles met the inclusion criteria, with the vast majority being retrospective in nature and based out of European centers. Sixteen articles focused on high-resolution metrics PAx, RAC, and PRx 55-15 , with 6 articles focusing on LAx and L-PRx. PAx may have a role in low ICP situations, where it appears to perform superior to PRx. RAC displays similar behavior to PRx, with a trend to stronger associations with favorable/unfavorable outcome at 6 months, and stronger parabolic relationship with CPP. PRx 55-15 provides a focused assessment on the vasogenic frequency range associated with cerebral autoregulation, with preliminary data supporting a strong association with outcome in TBI. LAx and L-PRx display varying This article is part of the Topical Collection on Brain trauma Electronic supplementary material The online version of this article (
Journal of Clinical Monitoring and Computing
Current accepted cerebrovascular reactivity indices suffer from the need of high frequency data capture and export for post-acquisition processing. The role for minute-by-minute data in cerebrovascular reactivity monitoring remains uncertain. The goal was to explore the statistical time-series relationships between intra-cranial pressure (ICP), mean arterial pressure (MAP) and pressure reactivity index (PRx) using both 10-s and minute data update frequency in TBI. Prospective data from 31 patients from 3 centers with moderate/severe TBI and high-frequency archived physiology were reviewed. Both 10-s by 10-s and minute-by-minute mean values were derived for ICP and MAP for each patient. Similarly, PRx was derived using 30 consecutive 10-s data points, updated every minute. While long-PRx (L-PRx) was derived via similar methodology using minute-by-minute data, with L-PRx derived using various window lengths (5, 10, 20, 30, 40, and 60 min; denoted L-PRx_5, etc.). Time-series autoregres...
Acta Neurochirurgica
Background Impaired cerebrovascular reactivity in adult traumatic brain injury (TBI) is known to be associated with poor outcome. However, there has yet to be an analysis of the association between the comprehensively assessed intracranial hypertension therapeutic intensity level (TIL) and cerebrovascular reactivity. Methods Using the Collaborative European Neuro Trauma Effectiveness Research in TBI (CENTER-TBI) high-resolution intensive care unit (ICU) cohort, we derived pressure reactivity index (PRx) as the moving correlation coefficient between slow-wave in ICP and mean arterial pressure, updated every minute. Mean daily PRx, and daily % time above PRx of 0 were calculated for the first 7 days of injury and ICU stay. This data was linked with the daily TIL-Intermediate scores, including total and individual treatment sub-scores. Daily mean PRx variable values were compared for each TIL treatment score via mean, standard deviation, and the Mann U test (Bonferroni correction for multiple comparisons). General fixed effects and mixed effects models for total TIL versus PRx were created to display the relation between TIL and cerebrovascular reactivity. Results A total of 249 patients with 1230 ICU days of high frequency physiology matched with daily TIL, were assessed. Total TIL was unrelated to daily PRx. Most TIL sub-scores failed to display a significant relationship with the PRx variables. Mild hyperventilation (p < 0.0001), mild hypothermia (p = 0.0001), high levels of sedation for ICP control (p = 0.0001), and use vasopressors for CPP management (p < 0.0001) were found to be associated with only a modest decrease in mean daily PRx or % time with PRx above 0. Conclusions Cerebrovascular reactivity remains relatively independent of intracranial hypertension therapeutic intensity, suggesting inadequacy of current TBI therapies in modulating impaired autoregulation. These findings support the need for This article is part of the Topical Collection on Brain trauma Electronic supplementary material The online version of this article (
Journal of Neurotrauma, 2016
Although a recent clinical trial (BEST TRIP) demonstrated no improvement in outcomes with invasive intracranial pressure (ICP) monitoring (ICPM) following severe traumatic brain injury (TBI), its generalizability has been called into question. In several global settings ICPM is not the standard of care and is used at the discretion of the attending neurosurgeon. Our objective was to determine the impact of ICPM on mortality and 6-month functional outcomes following severe TBI. The setting was a referral trauma center with 36 intensive care unit (ICU) beds and 300-600 TBI admissions per year. During a 2-year period data were prospectively entered into a severe TBI registry. Patients with severe TBI aged >12 years meeting Brain Trauma Foundation (BTF) criteria for ICPM were included in the study. Outcomes of interest were in-hospital mortality and poor 6-month functional outcome defined as Glasgow Outcome Scale (GOS) score of 3 or lower. A propensity score based analysis incorporating known predictors of outcome in TBI was utilized to examine the impact of ICPM on outcomes. Of 1345 patients meeting study criteria 497 (37%) underwent ICPM. In-hospital mortality was 35% (471/1345). Of 454 patients for whom 6-month outcome was available, 161 (35%) suffered a poor functional outcome. Following propensity score analysis ICPM use was associated with an 8% (p = 0.002) decrease in mortality but no significant effect (p = 0.2) on functional outcome. The use of ICPM following severe TBI was associated with decreased in-hospital mortality. Further clinical trials of ICPM in TBI may be warranted.
The Clinical Utility of the Conners’ Continuous Performance Test-II in Traumatic Brain Injury
Archives of Clinical Neuropsychology, 2016
Objective: The Conners' Continuous Performance Test Second Edition (CPT-II) is a measure commonly used in persons with suspected attentional deficits. Our study examined the utility of the CPT-II as a measure of attention in adults with traumatic brain injury (TBI) of varying severity. Method: As part of a larger investigation, several measures of cognitive functioning, including the CPT-II, were administered to 30 healthy control participants (HCP), 30 mild TBI participants (M-TBI), and 30 moderate to severe TBI participants (MS-TBI). Multivariate and correlational analyses compared group performances and examined convergent and divergent relationships between the CPT-II and various measures, including other tests of attention and neuropsychological function. Results: Group differences were found for four of six CPT-II variables, with the MS-TBI group exhibiting greater impairment, relative to M-TBI and HCP. In addition, the CPT-II commission and detectability variables were found to correlate significantly with TBI severity. The CPT-II variables also demonstrated correlations of varying magnitude between commonly used neuropsychological measures. Conclusions: These findings support the utility of the CPT-II for assessing attentional abilities in persons with TBI of varying severity, particularly those with moderate to severe status. Moreover, the current study also demonstrates relationships that are consistent with convergent validity but inconsistent findings with regard to divergent validity. As a result, the CPT-II measures components of attention that is unique to other commonly used neuropsychological measures of attentive functioning. Further research examining CPT-II performance in TBI populations is recommended.
Medicina, 2016
Background and objective: The aim of this study was to explore the association of cerebrovascular autoregulation (CA) and optimal cerebral perfusion pressure (CPP) managing conditions with the outcome of traumatic brain injury (TBI) patients including additional information about the patients' age and grade of diffuse axonal injury (DAI). Materials and methods: The CA monitoring of 28 TBI patients was performed by using ICM+ software (Cambridge, UK). The CA status estimating pressure reactivity indexes (PRx) and CPP data were processed in order to obtain information on the patient-specific treatment conditions by calculating the optimal CPP. Results: There was a negative correlation between the Glasgow outcome scale (GOS) score and PRx (r = À0.448 at hospital discharge and r = À0.402 after 6 months). The estimated threshold value PRx of >0.24 was associated with mortality. The correlation coefficients between the GOS score and the difference CPP-optimal CPP were 0.549 at hospital discharge and 0.484 after 6 months. The threshold value of CPP declination from DCPPopt per À6 mmHg was associated with mortality. Poorer outcome was predicted for elderly TBI patients (aged >47 years) and patients having a DAI grade of 3. Conclusions: The association of the GOS score with CPP, CA impairment conditions, age and diffuse axonal injury (DAI) grade showed that the outcomes of TBI patients were associated with patient-specific CPP management and better outcomes were obtained for younger patients, for patients having lower DAI grade and for patients whose CPP was kept within the range from the optimal CPP to the optimal CPP + 10 mmHg.