Visualization of the Intracranial Pressure and Time Burden in Childhood Brain Trauma: What We Have Learned One Decade on With KidsBrainIT

To validate the intracranial pressure (ICP) dose-response visualization plot for the first time in a novel prospectively collected pediatric traumatic brain injury (pTBI) data set from the multi-center, multi-national KidsBrainIT consortium. Prospectively collected minute-by-minute ICP and mean arterial blood pressure time series of 104 pTBI patients were categorized in ICP intensity-duration episodes. These episodes were correlated with the 6-month Glasgow Outcome Score (GOS) and displayed in a color-coded ICP dose-response plot. The influence of cerebrovascular reactivity and cerebral perfusion pressure (CPP) were investigated. The generated ICP dose-response plot on the novel data set was similar to the previously published pediatric plot. This study confirmed that higher ICP episodes were tolerated for a shorter duration of time, with an approximately exponential decay curve delineating the positive and negative association zones. ICP above 20 mm Hg for any duration in time was associated with poor outcome in our patients. Cerebrovascular reactivity state did not influence their respective transition curves above 10 mm Hg ICP. CPP below 50 mm Hg was not tolerated, regardless of ICP and duration, and was associated with worse outcome. The ICP dose-response plot was reproduced in a novel and independent pTBI data set. ICP above 20 mm Hg and CPP below 50 mm Hg for any duration in time were associated with worse outcome. This highlighted a pressing need to reduce pediatric ICP therapeutic thresholds used at the bedside.

Stratified Multivariate Multiscale Dispersion Entropy for Physiological Signal Analysis

Multivariate entropy quantification algorithms are becoming a prominent tool for the extraction of information from multi-channel physiological time-series. However, in the analysis of physiological signals from heterogeneous organ systems, certain channels may overshadow the patterns of others, resulting in information loss. Here, we introduce the framework of Stratified Entropy to prioritize each channels' dynamics based on their allocation to respective strata, leading to a richer description of the multi-channel time-series. As an implementation of the framework, three algorithmic variations of the Stratified Multivariate Multiscale Dispersion Entropy are introduced. These variations and the original algorithm are applied to synthetic time-series, waveform physiological time-series, and derivative physiological data. Based on the synthetic time-series experiments, the variations successfully prioritize channels following their strata allocation while maintaining the low computation time of the original algorithm. In experiments on waveform physiological time-series and derivative physiological data, increased discrimination capacity was noted for multiple strata allocations in the variations when benchmarked to the original algorithm. This suggests improved physiological state monitoring by the variations. Furthermore, our variations can be modified to utilize a priori knowledge for the stratification of channels. Thus, our research provides a novel approach for the extraction of previously inaccessible information from multi-channel time series acquired from heterogeneous systems.

Face Coverings, Aerosol Dispersion and Mitigation of Virus Transmission Risk

The SARS-CoV-2 virus is primarily transmitted through virus-laden fluid particles ejected from the mouth of infected people. Face covers can mitigate the risk of virus transmission but their outward effectiveness is not fully ascertained. Objective: by using a background oriented schlieren technique, we aim to investigate the air flow ejected by a person while quietly and heavily breathing, while coughing, and with different face covers. Results: we found that all face covers without an outlet valve reduce the front flow through by at least 63% and perhaps as high as 86% if the unfiltered cough jet distance was resolved to the anticipated maximum distance of 2-3 m. However, surgical and handmade masks, and face shields, generate significant leakage jets that may present major hazards. Conclusions: the effectiveness of the masks should mostly be considered based on the generation of secondary jets rather than on the ability to mitigate the front throughflow.

Application of Dispersion Entropy to Healthy and Pathological Heartbeat ECG Segments

Entropy quantification algorithms are a prominent tool for the quantification of irregularity in biological signal segments towards the characterization of the physiological state of individuals. This paper investigates the potential of Dispersion Entropy (DisEn) as a non-linear method to quantify the uncertainty of ECG signal segments for different types of heartbeats and the stratification of healthy heartbeats for the potential detection of developing pathologies in individuals. Our results indicate that the DisEn algorithm produces distributions with significant differences for the considered types of heartbeats, with higher DisEn values being more prominent in pathological heartbeats and normal heartbeats preceding them. This suggests that, with further research, DisEn algorithms can be integrated with heartbeat detection and classification algorithms for the improvement of medical prognosis through ECG signal processing.

Continuous intracranial pressure monitoring in severe traumatic brain injury in children

We present the results of the Romanian team for the multi-center grant “Paediatric Brain Monitoring with Information Technology (KidsBrainIT). Using IT Innovations to Improve Childhood Traumatic Brain Injury Intensive Care Management, Outcome, and Patient Safety”, acronym KidsBrainIT. Children aged 2 to 16 years who require intensive care management after sustaining traumatic severe brain injury are included in this study in three neurosurgical hospital: "Prof. Dr. N. Oblu" Clinical Emergency Hospital Iasi, "Sf. Maria" Children Clinical Emergency Hospital Iasi and "Bagdasar-Arseni" Clinical Emergency Hospital Bucharest. Continuous real-time intracranial pressure monitoring became a "gold standard" in TBI intensive-care management and ICP-lowering therapy is recommended when ICP is elevated above 20 mmHg or more. Continuous ICP and mean arterial blood pressure (MAP) monitoring allow calculation of cerebral perfusion pressure (CPP) and to establish of an optimal CPP. This study aims to improve the treatments and the outcomes in severe traumatic brain injury in children.

Visualizing Cerebrovascular Autoregulation Insults and Their Association with Outcome in Adult and Paediatric Traumatic Brain Injury

OBJECTIVE

The aim of this study is to assess visually the impact of duration and intensity of cerebrovascular autoregulation insults on 6-month neurological outcome in severe traumatic brain injury.

MATERIAL AND METHODS

Retrospective analysis of prospectively collected minute-by-minute intracranial pressure (ICP) and mean arterial blood pressure data of 259 adult and 99 paediatric traumatic brain injury (TBI) patients from multiple European centres. The relationship of the 6-month Glasgow Outcome Scale with cerebrovascular autoregulation insults (defined as the low-frequency autoregulation index above a certain threshold during a certain time) was visualized in a colour-coded plot. The analysis was performed separately for autoregulation insults occurring with cerebral perfusion pressure (CPP) below 50 mmHg, with ICP above 25 mmHg and for the subset of adult patients that did not undergo decompressive craniectomy.

RESULTS

The colour-coded plots showed a time-intensity-dependent association with outcome for cerebrovascular autoregulation insults in adult and paediatric TBI patients. Insults with a low-frequency autoregulation index above 0.2 were associated with worse outcomes and below -0.6 with better outcomes, with and approximately exponentially decreasing transition curve between the two intensity thresholds. All insults were associated with worse outcomes when CPP was below 50 mmHg or ICP was above 25 mmHg.

CONCLUSIONS

The colour-coded plots indicate that cerebrovascular autoregulation is disturbed in a dynamic manner, such that duration and intensity play a role in the determination of a zone associated with better neurological outcome.

Continuous Optimal CPP Based on Minute-by-Minute Monitoring Data: A Study of a Pediatric Population

This paper describes the use of minute-by-minute monitoring data to determine continuous optimal cerebral perfusion pressure (CPP) recommendations based on the autoregulatory status of pediatric patients with traumatic brain injury. Data from 79 children were retrospectively studied. Optimal CPP recommendations were obtained for the majority of the first 72 h of monitoring time. Actual CPP close to recommended CPP values was significantly associated with better outcome and was a significant independent predictor of better outcome when considering IMPACT model covariates in multivariate logistic regression.

Continuous Optimal CPP Based on Minute-by-Minute Monitoring Data: A Study of a Pediatric Population

This paper describes the use of minute-by-minute monitoring data to determine continuous optimal cerebral perfusion pressure (CPP) recommendations based on the autoregulatory status of pediatric patients with traumatic brain injury. Data from 79 children were retrospectively studied. Optimal CPP recommendations were obtained for the majority of the first 72 h of monitoring time. Actual CPP close to recommended CPP values was significantly associated with better outcome and was a significant independent predictor of better outcome when considering IMPACT model covariates in multivariate logistic regression.

Critical thresholds of intracranial pressure and cerebral perfusion pressure related to age in paediatric head injury

BACKGROUND

The principal strategy for managing head injury is to reduce the frequency and severity of secondary brain insults from intracranial pressure (ICP) and cerebral perfusion pressure (CPP), and hence improve outcome. Precise critical threshold levels have not been determined in head injured children.

OBJECTIVE

To create a novel pressure-time index (PTI) measuring both duration and amplitude of insult, and then employ it to determine critical insult thresholds of ICP and CPP in children.

METHODS

Prospective, observational, physiologically based study from Edinburgh and Newcastle, using patient monitored blood pressure, ICP, and CPP time series data. The PTI for ICP and CPP for 81 children, using theoretical values derived from physiological norms, was varied systematically to derive critical insult thresholds which delineate Glasgow outcome scale categories.

RESULTS

The PTI for CPP had a very high predictive value for outcome (receiver operating characteristic analyses: area under curve = 0.957 and 0.890 for mortality and favourable outcome, respectively) and was more predictive than for ICP. Initial physiological values most accurately predicted favourable outcome. The CPP critical threshold values determined for children aged 2-6, 7-10, and 11-15 years were 48, 54, and 58 mm Hg. respectively.

CONCLUSIONS

The PTI is the first substantive paediatric index of total ICP and CPP following head injury. The insult thresholds generated are identical to age related physiological values. Management guidelines for paediatric head injuries should take account of these CPP thresholds to titrate appropriate pressor therapy.

Inner calvarial erosion from traumatic subdural haematoma in infancy

CASE REPORT

This is a report of a case of a subdural haematoma in infancy of possible non-accidental aetiology with raised pericerebral pressure, which we postulate has eroded the inner table of the cranial bones and resulted in leakage of marrow precursor cells into the extradural space.

RESULT

Subdural tapping via the fontanelle has created a channel allowing subsequent ingress of nucleated red cell precursors into the subdural space. This addition to the subdural collection has prolonged its course necessitating subduro-peritoneal shunting.

Quantification of secondary CPP insult severity in paediatric head injured patients using a pressure-time index

This paper describes and validates a new Cumulative Pressure-Time Index (CPT) which takes into account both duration and degree of cerebral perfusion pressure (CPP) derangement and determines critical thresholds for CPP, in a paediatric head injury dataset. Sixty-six head-injured children, with invasive minute-to-minute intracranial pressure (ICP) and blood pressure monitoring, had their pre-set CPP derangement episodes (outside the normal range) identified in three childhood age-bands (2-6, 7-10, and 11-16 years) and global outcome assessed at six months post injury. The new cumulative pressure-time index more accurately predicted outcome than previously used summary measures and by varying the threshold CPP values, it was found that these physiological threshold values (< or = 48, < or = 52 and < or = 56 mmHg for 2-6, 7-10, and 11-16 years respectively) best predicted brain insult in terms of subsequent mortality and morbidity.

Graphical display of variability and inter-relationships of pressure signals in children with traumatic brain injury

A prospective observational study was undertaken to examine time series ICU data of pressure variables (mean arterial pressure (MAP), intracranial pressure (ICP) and cerebral perfusion pressure (CPP)) and relate their variability (SD) to outcome, together with simple graphical displays which could be useful at the ICU bedspace. Forty-three children (aged < 1-15 years) were admitted to the intensive care unit for Regional Neurosurgical Service, Edinburgh, following traumatic brain injury (TBI). The standard deviations from 221,291 validated pressure data measurements (representing three variables) were calculated for the duration of ICP monitoring (and in 48 h epochs from the time of injury). Data were displayed on polygraphs, and several well-defined 'patterns' were described. The standard deviations of MAP, ICP and CPP for the total duration of monitoring were found to be significantly related to survival (p = 0.003, <0.001 and 0.005, respectively), while the SD of ICP alone was strongly related to global recovery (p = 0.008) in the first 48 h post-injury. Patterns in 104 epochs (each of 48 h) were identified. Ninety-two were of the type I (MAP > CPP > ICP) pattern and 12 were of the non-type I pattern. Glasgow Outcome Scale scores at 12 months were significantly related to the dichotomized pattern type (Fisher's exact test p < 0.001 for both alive versus dead and independent versus dependent outcomes). Only one patient with type I pattern died in this series. While variability of ICP during the first 48 h post-injury is predictive of the outcome, the pattern behaviour of three pressure signals gives useful outcome prediction information throughout monitoring. These displays may help interpret some of the plethora of data produced at the bedside.

Cerebral atrophy following shaken impact syndrome and other non-accidental head injury (NAHI)

PURPOSE OF THE STUDY

To determine the frequency of cerebral atrophy and microcephaly in a group of children with sequential MRI brain scans after surviving a non-accidental head injury (n = 16).

METHODS

Serial head circumference measurements (OFC) were extracted and plotted on standard growth charts for each child retrospectively to determine the frequency of secondary microcephaly. Cerebral atrophy was diagnosed and quantified by measurement of the ventricular/cortical ratio on coronal images of the sequential scans.

RESULTS

Acquired microcephaly was found in 15 children (93.8%) over a median follow-up period of 67.93 weeks. There was a significant reduction in the median Z-score for the OFC at the most recent follow-up when compared with that at presentation (p < 0.001, Wilcoxon Signed Rank Test). Cerebral atrophy was found to be the cause of the microcephaly in eight of the 15 children and was evident as early as 9 days after presentation.

CONCLUSION

A large proportion of the cohort (93.8%) develops acquired microcephaly after an inflicted head injury and cerebral atrophy is responsible in half of these cases.

Long-term risks and benefits of a separate CSF access device with ventriculoperitoneal shunting in childhood hydrocephalus

To determine the long-term risks and benefits of a separate CSF reservoir in the management of 52 children (23 males, 29 females) with shunted hydrocephalus, a retrospective study was performed comparing the use and complications after separate reservoir insertion, with a prereservoir control period. Median age at first shunt insertion was 1 month and median age at reservoir insertion was 2 years 6 months. Median follow-up for shunt with the additional reservoir was 19 years 1 month. There was no mortality due to shunt failure nor CNS infection, and there were significantly fewer episodes of ventriculitis (p < 0.01) and shunt blockage (p < 0.0001) compared with the prereservoir period. There was no hemiplegia, epilepsy, visual, nor cognitive loss from the additional reservoir. The reservoir was used for access in 344 attendances (mean 6.62 attendances per patient) for diagnosis or treatment of raised pressure or CNS infection. It was concluded that a separate CSF reservoir is useful in the long-term management of patients with shunted hydrocephalus and is without mortality or significant increased morbidity.