Early changes in cerebral autoregulation among youth hospitalized after sports-related traumatic brain injury

Transcranial Doppler Ultrasound and Concussion-Supplemental Symptoms with Physiology: A Systematic Review

Sport-related concussion (SRC) can impair the cerebrovasculature both acutely and chronically. Transcranial Doppler (TCD) ultrasound assessment has the potential to illuminate the mechanisms of impairment and provide an objective evaluation of SRC. The current systematic review investigated studies employing TCD ultrasound assessment of intracranial arteries across three broad categories of cerebrovascular regulation: neurovascular coupling (NVC), cerebrovascular reactivity (CVR), and dynamic cerebral autoregulation (dCA). The current review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42021275627). The search strategy was applied to PubMed, as this database indexes all biomedical journals. Original articles on TCD for athletes with medically diagnosed SRC were included. Title/abstract and full-text screening were completed by three authors. Two authors completed data extraction and risk of bias using the Methodological Index for Non-Randomized Studies and Scottish Intercollegiate Guideline Network checklists. Of the 141 articles identified, 14 met the eligibility criteria. One article used an NVC challenge, eight assessed CVR, and six investigated dCA. Methodologies varied widely among studies, and results were heterogeneous. There was evidence of cerebrovascular impairment in all three domains roughly 2 days post-SRC, but the magnitude and recovery of these impairments were not clear. There was evidence that clinical symptom resolution occurred before cerebrovascular function, indicating that physiological deficits may persist despite clinical recovery and return to play. Collectively, this emphasizes an opportunity for the use of TCD to illuminate the cerebrovascular deficits caused by SRC. It also highlights that there is need for consistent methodological rigor when employing TCD in a SRC population.

Cerebral autoregulation in paediatric and neonatal intensive care: A scoping review

Deranged cerebral autoregulation (CA) is associated with worse outcome in adult brain injury. Strategies for monitoring CA and maintaining the brain at its 'best CA status' have been implemented, however, this approach has not yet developed for the paediatric population. This scoping review aims to find up-to-date evidence on CA assessment in children and neonates with a view to identify patient categories in which CA has been measured so far, CA monitoring methods and its relationship with clinical outcome if any. A literature search was conducted for studies published within 31st December 2022 in 3 bibliographic databases. Out of 494 papers screened, this review includes 135 studies. Our literature search reveals evidence for CA measurement in the paediatric population across different diagnostic categories and age groups. The techniques adopted, indices and thresholds used to assess and define CA are heterogeneous. We discuss the relevance of available evidence for CA assessment in the paediatric population. However, due to small number of studies and heterogeneity of methods used, there is no conclusive evidence to support universal adoption of CA monitoring, technique, and methodology. This calls for further work to understand the clinical impact of CA monitoring in paediatric and neonatal intensive care.

A Pilot Prospective Observational Study of Cerebral Autoregulation and 12-Month Outcomes in Children With Complex Mild Traumatic Brain Injury: The Argument for Sufficiency Conditions Affecting TBI Outcomes

BACKGROUND

The relationship between cerebral autoregulation and outcomes in pediatric complex mild traumatic brain injury (TBI) is unknown, and explored in this study.

METHODS

We conducted a prospective observational study of patients aged 0 to 18 years hospitalized with complex mild TBI (admission Glasgow Coma Scale score 13 to 15 with either abnormal computerized tomogram of the head or history of loss of consciousness). Cerebral autoregulation was tested using transcranial Doppler ultrasonography, and impaired autoregulation defined as autoregulation index<0.4. We collected Glasgow Outcome Scale Extended-Pediatrics score and health-related quality of life data at 3, 6, and 12 months after discharge.

RESULTS

Twenty-four patients aged 1.8 to 16.6 years (58.3% male) with complete 12-month outcome data were included in the analysis. Median admission Glasgow Coma Scale score was 15 (range: 13 to 15), median injury severity score was 12 (range: 4 to 29) and 23 patients (96%) had isolated TBI. Overall, 10 (41.7%) patients had impaired cerebral autoregulation. Complete recovery was observed in 6 of 21 (28.6%) children at 3 months, in 4 of 16 (25%) children at 6 months, and in 8 of 24 (33.3%) children at 12 months. There was no difference in median (interquartile range) Glasgow Outcome Scale Extended-Pediatrics score (2 [2.3] vs. 2 [interquartile range 1.3]) or health-related quality of life scores (91.5 [21.1] vs. 90.8 [21.6]) at 12 months between those with intact and impaired autoregulation, respectively. Age-adjusted hypotension occurred in 2/24 (8.3%) patients.

CONCLUSION

Two-thirds of children with complex mild TBI experienced incomplete functional recovery at 1 year. The co-occurrence of hypotension and cerebral autoregulation may be a sufficiency condition needed to affect TBI outcomes.

The Legacy of the TTASAAN Report-Premature Conclusions and Forgotten Promises: A Review of Policy and Practice Part I

Brain perfusion single photon emission computed tomography (SPECT) scans were initially developed in 1970's. A key radiopharmaceutical, hexamethylpropyleneamine oxime (HMPAO), was originally approved in 1988, but was unstable. As a result, the quality of SPECT images varied greatly based on technique until 1993, when a method of stabilizing HMPAO was developed. In addition, most SPECT perfusion studies pre-1996 were performed on single-head gamma cameras. In 1996, the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology (TTASAAN) issued a report regarding the use of SPECT in the evaluation of neurological disorders. Although the TTASAAN report was published in January 1996, it was approved for publication in October 1994. Consequently, the reported brain SPECT studies relied upon to derive the conclusions of the TTASAAN report largely pre-date the introduction of stabilized HMPAO. While only 12% of the studies on traumatic brain injury (TBI) in the TTASAAN report utilized stable tracers and multi-head cameras, 69 subsequent studies with more than 23,000 subjects describe the utility of perfusion SPECT scans in the evaluation of TBI. Similarly, dementia SPECT imaging has improved. Modern SPECT utilizing multi-headed gamma cameras and quantitative analysis has a sensitivity of 86% and a specificity of 89% for the diagnosis of mild to moderate Alzheimer's disease-comparable to fluorodeoxyglucose positron emission tomography. Advances also have occurred in seizure neuroimaging. Lastly, developments in SPECT imaging of neurotoxicity and neuropsychiatric disorders have been striking. At the 25-year anniversary of the publication of the TTASAAN report, it is time to re-examine the utility of perfusion SPECT brain imaging. Herein, we review studies cited by the TTASAAN report vs. current brain SPECT imaging research literature for the major indications addressed in the report, as well as for emerging indications. In Part II, we elaborate technical aspects of SPECT neuroimaging and discuss scan interpretation for the clinician.

Experience with clinical cerebral autoregulation testing in children hospitalized with traumatic brain injury: Translating research to bedside

OBJECTIVE

To report our institutional experience with implementing a clinical cerebral autoregulation testing order set with protocol in children hospitalized with traumatic brain injury (TBI).

METHODS

After IRB approval, we examined clinical use, patient characteristics, feasibility, and safety of cerebral autoregulation testing in children aged <18 years between 2014 and 2021. A clinical order set with a protocol for cerebral autoregulation testing was introduced in 2018.

RESULTS

25 (24 severe TBI and 1 mild TBI) children, median age 13 years [IQR 4.5; 15] and median admission GCS 3[IQR 3; 3.5]) underwent 61 cerebral autoregulation tests during the first 16 days after admission [IQR1.5; 7; range 0-16]. Testing was more common after implementation of the order set (n = 16, 64% after the order set vs. n = 9, 36% before the order set) and initiated during the first 2 days. During testing, patients were mechanically ventilated (n = 60, 98.4%), had invasive arterial blood pressure monitoring (n = 60, 98.4%), had intracranial pressure monitoring (n = 56, 90.3%), brain-tissue oxygenation monitoring (n = 56, 90.3%), and external ventricular drain (n = 13, 25.5%). Most patients received sedation and analgesia for intracranial pressure control (n = 52; 83.8%) and vasoactive support (n = 55, 90.2%) during testing. Cerebral autoregulation testing was completed in 82% (n = 50 tests); 11 tests were not completed [high intracranial pressure (n = 5), high blood pressure (n = 2), bradycardia (n = 2), low cerebral perfusion pressure (n = 1), or intolerance to blood pressure cuff inflation (n = 1)]. Impaired cerebral autoregulation on first assessment resulted in repeat testing (80% impaired vs. 23% intact, RR 2.93, 95% CI 1.06:8.08, p = 0.03). Seven out of 50 tests (14%) resulted in a change in cerebral hemodynamic targets.

CONCLUSION

Findings from this series of children with TBI indicate that: (1) Availability of clinical order set with protocol facilitated clinical cerebral autoregulation testing, (2) Clinicians ordered cerebral autoregulation tests in children with severe TBI receiving high therapeutic intensity and repeatedly with impaired status on the first test, (3) Clinical cerebral autoregulation testing is feasible and safe, and (4) Testing results led to change in hemodynamic targets in some patients.

Sports audiology: Ear hygiene practices of gym users who wear earphones

BACKGROUND

Technological advancements have facilitated the demand for electronic systems to track and measure progress during exercise activities. Electronic devices with music applications, such as iPods and smartphones, are popular during gym sessions as they support the ambiance to one's exercise programme. Earphones are the popular choice for the transmission of music to the gym user's ear. There is a direct correlation between the cardiovascular health and the aural health because of the effect of increased blood supply to the auditory system. Therefore, this research study explores the ear hygiene of gym users.

OBJECTIVES

This study aimed at determining the ear hygiene and middle-ear status of gym users who wore earphones whilst exercising.

METHOD

A purposive sampling method was adopted. Data were collected in two phases: phase 1 via a questionnaire and phase 2 included an otoscopic examination and tympanometry. Qualitative and quantitative data were analysed.

RESULTS

Fifty-four participants were included. Ear hygiene was not a priority for all gym users. The results revealed that 87% of the participants randomly cleaned their ears; however, 59% were cleaning their earphones. The middle ear assessment indicated that 17% of the participants presented with pathological indicators. Participants requested for the implementation of educational programmes pertaining to infection control measures for proper ear hygiene.

CONCLUSION

There is a dearth of health and wellness educational programmes that include ear hygiene practices, necessitating the development of prevention and promotion programmes for this niche area in audiology. The need for guidelines pertaining to ear hygiene practices amongst gym users is vital to ensure that the auditory system is monitored and protected when individuals participate in exercise sessions.

Anesthesia and the brain after concussion

PURPOSE OF REVIEW

To provide an overview of acute and chronic repeated concussion. We address epidemiology, pathophysiology, anesthetic utilization, and provide some broad-based care recommendations.

RECENT FINDINGS

Acute concussion is associated with altered cerebral hemodynamics. These aberrations can persist despite resolution of signs and symptoms. Multiple repeated concussions can cause chronic traumatic encephalopathy, a disorder associated with pathologic findings similar to some organic dementias. Anesthetic utilization is common following concussion, especially soon after injury, a time when the brain may be most vulnerable to secondary injury.

SUMMARY

Brain physiology may be abnormal following concussion and these abnormalities may persist despite resolutions of clinical manifestations. Those with recent concussion or chronic repeated concussion may be susceptible to secondary injury in the perioperative period. Clinicians should suspect concussion in any patient with recent trauma and strive to maintain cerebral homeostasis in the perianesthetic period.

Cardiac-cerebral-renal associations in pediatric traumatic brain injury: Preliminary findings

OBJECTIVE

The clinical epidemiology of organ outcomes in pediatric traumatic brain injury (TBI) has not been examined. We describe associated markers of cerebral, cardiac and renal injury after pediatric TBI.

DESIGN

Prospective observational study.

PATIENTS

Children 0-18 years who were hospitalized with TBI.

MEASUREMENTS

Measures of myocardial (at least one elevated plasma troponin [cTnI] ≥ 0.4 ng/ml) and multiorgan (hemodynamic variables, cerebral perfusion, and renal) function were examined within the first ten days of hospital admission and within 24 h of each other.

MAIN RESULTS

Data from 28 children who were 11[IQR 10.3] years, male (64.3%), with isolated TBI (67.9%), injury severity score (ISS) 25[10], and admission Glasgow coma score (GCS) 11[9] were examined. Overall, 50% (14 children) had elevated cTnI, including those with isolated TBI (57.9%; 11/19), polytrauma (33.3%; 3/9), mild TBI (57.1% 8/14), and severe TBI (42.9%; 6/11). Elevated cTnI occurred within the first six days of admission and across all age groups, in both sexes, and regardless of TBI lesion type, GCS, and ISS. Age-adjusted admission tachycardia was associated with cTnI elevation (AUC 0.82; p < 0.001). Reduced urine output occurred more commonly in patients with isolated TBI (27.3% elevated cTnI vs. 0% normal cTnI).

CONCLUSIONS

Myocardial injury commonly occurs during the first six days after pediatric TBI irrespective of injury severity, age, sex, TBI lesion type, or polytrauma. Age-adjusted tachycardia may be a clinical indicator of myocardial injury, and elevated troponin may be associated with cardio-cerebro-renal dysfunction.

Recent Preoperative Concussion and Postoperative Complications: A Retrospective Matched-cohort Study

BACKGROUND

Physiological alterations during the perianesthetic period may contribute to secondary neurocognitive injury after a concussion.

METHODS

Patients exposed to concussion and who received an anesthetic within 90 days were matched to unexposed patients without concussion. Intraoperative and postoperative events were compared. Subgroup analyses assessed relationships among patients with a concussion in the prior 30, 31 to 60, and 61 to 90 days and their respective unexposed matches. To facilitate identification of potential targets for further investigation, statistical comparisons are reported before, as well as after, correction for multiple comparisons.

RESULTS

Sixty concussion patients were matched to 176 unexposed patients. Before correction, 28.3% postconcussion versus 14.8% unexposed patients reported postanesthesia care unit pain score≥7 (P=0.02); 16.7% concussion versus 6.5% unexposed patients reported headache within 90 days of anesthesia (P=0.02) and 23.5% of patients who received surgery and anesthesia within 30 days of concussion experienced headache within 90 days of anesthesia compared with 7.1% in the unexposed group (P=0.01). Patients who experienced concussion and had anesthesia between 31 and 60 days after injury had a postanesthesia care unit Richmond Agitation and Sedation Scale score of -1.61±1.29 versus a score of -0.2±0.45 in unexposed patients (P=0.002). After adjusting the P-value threshold for multiple comparisons, the P-value for significance was instead 0.0016 for the overall cohort. Our study revealed no significant associations with application of adjusted significance thresholds.

CONCLUSIONS

There were no differences in intraoperative and postoperative outcomes in patients with recent concussion compared with unexposed patients. Before correction for multiple comparisons, several potential targets for further investigation are identified. Well-powered studies are warranted.

Translational approach towards determining the role of cerebral autoregulation in outcome after traumatic brain injury

Cerebral autoregulation is impaired after traumatic brain injury (TBI), contributing to poor outcome. In the context of the neurovascular unit, cerebral autoregulation contributes to neuronal cell integrity and clinically Glasgow Coma Scale is correlated to intactness of autoregulation after TBI. Cerebral Perfusion Pressure (CPP) is often normalized by use of vasoactive agents to increase mean arterial pressure (MAP) and thereby limit impairment of cerebral autoregulation and neurological deficits. However, current vasoactive agent choice used to elevate MAP to increase CPP after TBI is variable. Vasoactive agents, such as phenylephrine, dopamine, norepinephrine, and epinephrine, clinically have not sufficiently been compared regarding effect on CPP, autoregulation, and survival after TBI. The cerebral effects of these clinically commonly used vasoactive agents are incompletely understood. This review will describe translational studies using a more human like animal model (the pig) of TBI to identify better therapeutic strategies to improve outcome post injury. These studies also investigated the role of age and sex in outcome and mechanism(s) involved in improvement of outcome in the setting of TBI. Additionally, this review considers use of inhaled nitric oxide as a novel neuroprotective strategy in treatment of TBI.

Pediatric Traumatic Brain Injury and Associated Topics: An Overview of Abusive Head Trauma, Nonaccidental Trauma, and Sports Concussions

Pediatric traumatic brain injury (TBI) uniquely affects the pediatric population. Abusive head trauma (AHT) is a subset of severe pediatric TBI usually affecting children in the first year of life. AHT is a form of nonaccidental trauma. Sports-related TBI resulting in concussion is a milder form of TBI affecting older children. Current recommended perioperative management of AHT and sports concussions relies on general pediatric TBI guidelines. Research into more specific pediatric TBI screening and management goals is ongoing. This article reviews the epidemiology, mechanisms, clinical signs, and management of AHT and sports-related concussions.

Prevalence, Evolution, and Extent of Impaired Cerebral Autoregulation in Children Hospitalized With Complex Mild Traumatic Brain Injury

OBJECTIVES

To examine cerebral autoregulation in children with complex mild traumatic brain injury.

DESIGN

Prospective observational convenience sample.

SETTING

PICU at a level I trauma center.

PATIENTS

Children with complex mild traumatic brain injury (trauma, admission Glasgow Coma Scale score 13-15 with either abnormal head CT, or history of loss of consciousness).

INTERVENTIONS

Cerebral autoregulation was tested using transcranial Doppler ultrasound between admission day 1 and 8.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was prevalence of impaired cerebral autoregulation (autoregulation index < 0.4),determined using transcranial Doppler ultrasonography and tilt testing. Secondary outcomes examined factors associated with and evolution and extent of impairment. Cerebral autoregulation testing occurred in 31 children 10 years (SD, 5.2 yr), mostly male (59%) with isolated traumatic brain injury (91%), median admission Glasgow Coma Scale 15, Injury Severity Scores 14.2 (SD, 7.7), traumatic brain injury due to fall (50%), preadmission loss of consciousness (48%), and abnormal head CT scan (97%). Thirty-one children underwent 56 autoregulation tests. Impaired cerebral autoregulation occurred in 15 children (48.4%) who underwent 19 tests; 68% and 32% of tests demonstrated unilateral and bilateral impairment, respectively. Compared with children on median day 6 of admission after traumatic brain injury, impaired autoregulation was most common in the first 5 days after traumatic brain injury (day 1: relative risk, 3.7; 95% CI, 1.9-7.3 vs day 2: relative risk, 2.7; 95% CI, 1.1-6.5 vs day 5: relative risk, 1.33; 95% CI, 0.7-2.3). Children with impaired autoregulation were older (12.3 yr [SD, 1.3 yr] vs 8.7 yr [SD, 1.1 yr]; p = 0.04) and tended to have subdural hematoma (64% vs 44%), epidural hematoma (29% vs 17%), and subarachnoid hemorrhage (36% vs 28%). Eight children (53%) were discharged home with ongoing impaired cerebral autoregulation.

CONCLUSIONS

Impaired cerebral autoregulation is common in children with complex mild traumatic brain injury, despite reassuring admission Glasgow Coma Scale 13-15. Children with complex mild traumatic brain injury have abnormal cerebrovascular hemodynamics, mostly during the first 5 days. Impairment commonly extends to the contralateral hemisphere and discharge of children with ongoing impaired cerebral autoregulation is common.