A Cross-Sectional Study on Cerebral Hemodynamics After Mild Traumatic Brain Injury in a Pediatric Population (original) (raw)
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Cerebrovascular dynamics after pediatric traumatic brain injury
Frontiers in Physiology
Objective: We aimed to investigate model-based indices of cerebrovascular dynamics after pediatric traumatic brain injury (TBI) using transcranial Doppler ultrasound (TCD) integrated into multimodality neurologic monitoring (MMM).Methods: We performed a retrospective analysis of pediatric TBI patients undergoing TCD integrated into MMM. Classic TCD characteristics included pulsatility indices and systolic, diastolic and mean flow velocities of the bilateral middle cerebral arteries. Model-based indices of cerebrovascular dynamics included the mean velocity index (Mx), compliance of the cerebrovascular bed (Ca), compliance of the cerebrospinal space (Ci), arterial time constant (TAU), critical closing pressure (CrCP) and diastolic closing margin (DCM). Classic TCD characteristics and model-based indices of cerebrovascular dynamics were investigated in relation to functional outcomes and intracranial pressure (ICP) using generalized estimating equations with repeated measures. Functio...
Cerebral blood flow as a predictor of outcome following traumatic brain injury
Journal of Neurosurgery, 1997
✓ As part of a prospective study of the cerebrovascular effects of head injury, 54 moderate and severely injured patients underwent 184 133Xe—cerebral blood flow (CBF) studies to determine the relationship between the period of maximum blood flow and outcome. The lowest blood flows were observed on the day of injury (Day 0) and the highest CBFs were documented on postinjury Days 1 to 5. Patients were divided into three groups based on CBF values obtained during this period of maximum flow: Group 1 (seven patients), CBF less than 33 ml/100 g/minute on all determinations; Group 2 (13 patients), CBF both less than and greater than or equal to 33 ml/100 g/minute; and Group 3 (34 patients), CBF greater than or equal to 33 ml/100 g/minute on all measurements. For Groups 1, 2, and 3, mean CBF during Days 1 to 5 postinjury was 25.7 ± 4, 36.5 ± 4.2, and 49.4 ± 9.3 ml/100 g/minute, respectively, and PaCO2 at the time of the CBF study was 31.4 ± 6, 32.7 ± 2.9, and 33.4 ± 4.7 mm Hg, respectivel...
Cerebral Perfusion changes in Post-Concussion Syndrome: A prospective controlled cohort study
Journal of neurotrauma, 2016
The biology of post-concussive symptoms is unclear. Symptoms are often increased during activities, and have been linked to decreased cerebrovascular reactivity and perfusion. The aim of this study was to examine cerebral blood flow (CBF) in children with different clinical recovery patterns following mild traumatic brain injury (mTBI). This was a prospective controlled cohort study of children with mTBI (ages 8 to 18 years) who were symptomatic with post concussive symptoms at one month post-injury (symptomatic, n=27) and children who had recovered quickly (asymptomatic, n=24). Pseudocontinuous arterial spin labeling MRI was used to quantify CBF. The mTBI groups were imaged at 40 days post-injury. Global and regional CBF were compared to healthy controls of similar age and sex but without a history of mTBI (n=21). Seventy-two participants (mean age: 14.1years) underwent neuroimaging. Significant differences in CBF were found: global CBF was higher in the symptomatic group and lower...
Evaluation of hemodynamic responses in head injury patients with transcranial doppler monitoring
Acta Neurochirurgica, 1997
Transcranial Doppler (TCD) can monitor middle cerebral artery (MCA) velocity which can be recorded simultaneously with other physiologic parameters such as end tidal (Et) CO2, arterial blood pressure and intracranial pressure (ICP), in head injured patients. Relative changes in MCA velocity can be used to reflect relative MCA blood flow changes during ICP waves, and also to evaluate cerebral autoregulation, CO2 reactivity and hemodynamic responses to mannitol and barbiturates. The utility and practicality of short intervals of TCD monitoring to evaluate hemodynamic resposnes, was evaluated in a group of 22 head injured patients (average Glasgow coma score 6). During ICP A waves, MCA velocity always decreased during the peak of the wave, and during ICP B waves, fluctuated synchronously with the ICP. Dynamic cerebral autoregulation, and reactivity to CO2, were reduced within 48 hours of admission, hnpaired cerebral autoregulation within 48 hours of admission did not correlate with outcome at 1 month. Mannitol infusion caused an increase in MCA velocity (15.4 + 7.9%) which was significantly correlated to the impairment of dynamic autoregulation (r = 0.54, p < 0.0001). The MCA velocity response to a test dose of barbiturates was significantly correlated to the ICP (r=0.61, p<0.01) response as well as to the CO2 reactivity (r = 0.37, p < 0.05).
Surgical Neurology, 2005
Background: Trans-cranial Doppler (TCD) studies after head injury have been done in the first 24 hours after injury and do not specify the exact interval between injury and time of recordings. We have studied cerebral blood flow changes in patients with severe head injury using serial TCD starting within 6 hours after trauma, and present our findings and its correlation with clinical outcome. Methods: Thirty-two patients with closed severe brain injuries formed the study group. Six-hourly serial TCD studies were done starting within 6 hours after trauma until 48 hours after trauma or death of the patient, whichever was earlier. Flow velocities of the extracranial internal carotid (V EC-ICA ) and middle cerebral artery (V MCA ) were recorded to identify vasospasm, hyperemia, or oligemia. Serial changes in flow velocities were correlated with the clinical outcome of the patients at 12 months' follow-up after injury. Result: Oligemia (n = 30) and vasospasm (n = 2) were the earliest changes observed within 6 hours of trauma. In the oligemia group, persistent oligemia (n = 14), hyperemia (n = 6), normal flow velocity (n = 5), and vasospasm developing within 24 hours (n = 5) were observed. Eight patients developed vasospasm after 24 hours. All patients with persistent oligemia and vasospasm developing within 24 hours had poor outcome. Conclusion: Oligemia is the most common change within 6 hours of head injury. Persistence of oligemia beyond 24 hours is associated with poor outcome. Early (within 24 hours posttrauma) onset of vasospasm is associated with poor outcome; however, delayed ( N 24 hours after trauma) vasospasm is not associated with poor outcome. D Abbreviations: CBF, Cerebral blood flow velocity; CT, Computed tomography; ICP, Intracranial pressure; MCA, Middle cerebral artery; MFV, Mean flow velocity; TCD, Trans-cranial Doppler; V EC-ICA , Flow velocity of extracranial internal carotid artery; V MCA , Flow velocity of middle cerebral artery.
Journal of Neurosurgery: Pediatrics, 2015
OBJECT The aim of this study was to determine the relationship between transcranial Doppler (TCD) derived pulsatility index (PI), end diastolic flow velocity (Vd), and intracranial pressure (ICP). The subjects in this study were 36 children admitted after severe traumatic brain injury (TBI) (postresuscitation Glasgow Coma Scale ≤ 8) undergoing invasive ICP monitoring. METHODS Subjects underwent a total of 148 TCD studies. TCD measurements of systolic flow velocity (Vs), Vd, and mean flow velocity (Vm) were performed on the middle cerebral artery (MCA) ipsilateral to the ICP monitor. The PI was calculated by the TCD software (Vs-Vd/Vm). ICP registrations were made in parallel with TCD measurements. RESULTS Using a PI threshold of 1.3, postinjury Day 0–1 PI had 100% sensitivity and 82% specificity at predicting an ICP ≥ 20 mm Hg (n = 8). During this time frame, a moderately strong relationship was observed between the MCA PI and actual ICP (r = 0.611, p = 0.01). When using a threshold...
Symptom correlates of cerebral blood flow following acute concussion
NeuroImage: Clinical, 2017
Concussion is associated with significant symptoms within hours to days post-injury, including disturbances in physical function, cognition, sleep and emotion. However, little is known about how subjective impairments correlate with objective measures of cerebrovascular function following brain injury. This study examined the relationship between symptoms and cerebral blood flow (CBF) in individuals following sport-related concussion. Seventy university level athletes had CBF measured using Arterial Spin Labelling (ASL), including 35 with acute concussion and 35 matched controls and their symptoms were assessed using the Sport Concussion Assessment Tool 3 (SCAT3). For concussed athletes, greater total symptom severity was associated with elevated posterior cortical CBF, although mean CBF was not significantly different from matched controls (p = 0.46). Examining symptom clusters, athletes reporting greater cognitive symptoms also had lower frontal and subcortical CBF, relative to athletes with greater somatic symptoms. The "cognitive" and "somatic" subgroups also exhibited significant differences in CBF relative to controls (p ≤ 0.026). This study demonstrates objective CBF correlates of symptoms in recently concussed athletes and shows that specific symptom clusters may have distinct patterns of altered CBF, significantly extending our understanding of the neurobiology of concussion and traumatic brain injury.
Cerebrovascular reactivity changes in acute concussion: a controlled cohort study
Quantitative imaging in medicine and surgery, 2021
Background Evidence suggests that cerebrovascular reactivity (CVR) increases within the first week after the incidence of concussion, indicating a disruption of normal autoregulation. We sought to extend these findings by investigating the effects of acute concussion on the speed of CVR response and by visualizing global and regional impairments in individual patients with acute concussion. Methods Twelve patients aged 18-40 years who experienced concussion less than a week before this prospective study were included. Twelve age and sex-matched healthy subjects constituted the control group. In all subjects, CVR was assessed using blood oxygenation level-dependent (BOLD) echo-planar imaging with a 3.0T MRI scanner, in combination with changes in end-tidal partial pressure of CO2 (PETCO2). In each subject, we calculated the CVR amplitude and CVR response time in the gray and white matter using a step and ramp PETCO2 challenge. In addition, a separate group of 39 healthy controls who ...
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.
Child's Nervous System
Objective To identify if cerebral perfusion pressure (CPP) can be non-invasively estimated by either of two methods calculated using transcranial Doppler ultrasound (TCD) parameters. Design Retrospective review of previously prospectively gathered data. Setting Pediatric intensive care unit in a tertiary care referral hospital. Patients Twenty-three children with severe traumatic brain injury (TBI) and invasive intracranial pressure (ICP) monitoring in place. Interventions TCD evaluation of the middle cerebral arteries was performed daily. CPP at the time of the TCD examination was recorded. For method 1, estimated cerebral perfusion pressure (CPPe) was calculated as: CPPe = MAP × (diastolic flow (Vd)/ mean flow (Vm)) + 14. For method 2, critical closing pressure (CrCP) was identified as the intercept point on the x-axis of the linear regression line of blood pressure and flow velocity parameters. CrCP/CPPe was then calculated as MAP-CrCP. Measurements and main results One hundred eight paired measurements were available. Using patient averaged data, correlation between CPP and CPPe was significant (r = 0.78, p = < 0.001). However, on Bland-Altman plots, bias was 3.7 mmHg with 95% limits of agreement of − 17 to + 25 for CPPe. Using patient averaged data, correlation between CPP and CrCP/CPPe was significant (r = 0.59, p = < 0.001), but again bias was high at 11 mmHg with wide 95% limits of agreement of − 15 to + 38 mmHg. Conclusions CPPe and CrCP/CPPe do not have clinical value to estimate the absolute CPP in pediatric patients with TBI.