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Continuous Recording of the Ventricular-Fluid Pressure in Patients with Severe Acute Traumatic Brain Injury
... ICP monitoring was further advanced in the 1960s by Lundberg and his colleagues, who measured cerebral ventricular fluid pressure using a polyethylene catheter coupled to a pressure transducer. Their work established monitoring of intraventricular pressure as a valid and safe alternative [33][34][35]. The aim of Lundberg's thesis was to provide a method for ventricular cannulation that was minimally traumatic, feasible, had a low risk of infection and leakage, and facilitated recording with continuous flow of the ICP. ...
... The aim of Lundberg's thesis was to provide a method for ventricular cannulation that was minimally traumatic, feasible, had a low risk of infection and leakage, and facilitated recording with continuous flow of the ICP. In addition, he described three ICP wave patterns associated with intracranial pathologies [11,[33][34][35]. "A" waves represented increase in ICP to levels of 50 to 100 mmHg that maintained a plateau for 5-20 min, followed by an abrupt drop. ...
... These waves could be directly related to cerebral blood flow (CBF) and vessel diameter but were of uncertain origin and relevance. "C" waves, also known as Mayer's wave, represented arterial wave reflexes and were associated with cardiac and respiratory cycles [11,[33][34][35]. ...
Traumatic brain injury (TBI) is a complex condition that requires specialized care. This chapter traces the history of TBI management from ancient times to the present day, revealing how medical knowledge and practice have advanced over the centuries. It covers the following topics:
The origins of TBI care in prehistoric cultures, where trepanation was performed to treat head injuries and release “evil spirits.”
The contributions of ancient civilizations, such as Egypt, Greece, and Rome, to the understanding of the brain, its functions, and its diseases. It highlights the role of Hippocrates who wrote the first treatise on head injuries and advocated for rational and humane treatment of TBI patients.
The discoveries of the Middle Ages and the Renaissance, such as the existence of cerebrospinal fluid (CSF), the concept of intracranial pressure (ICP), and the anatomy and physiology of the nervous system. It acknowledges the work of influential figures like Nicola Massa, Monro, Kellie, and Vesalius, who laid the groundwork for modern neuroscience.
The emergence of neurosurgery in the nineteenth and twentieth centuries, spurred by the challenges of wartime injuries and the development of new technologies, such as anesthesia and aseptic techniques. It discusses the case of Phineas Gage, who survived a penetrating brain injury and provided insights into brain localization. It also mentions the achievements of Harvey Cushing, the father of neurosurgery, and Santiago Ramon y Cajal, the founder of modern neurobiology.
The establishment of the Brain Trauma Foundation (BTF) in the late twentieth century, which produced evidence-based clinical practice guidelines for TBI management that have led to marked improvement in patient outcomes. It emphasizes the benefits of compliance with these guidelines and the need for ongoing research and education to further TBI care.
The evolution of neuromonitoring, which is a vital component of TBI care that allows for the direct assessment of brain physiology. It reviews the history of ICP monitoring, from the lumbar puncture technique first described by Heinrich Quincke in 1891 to the current invasive and noninvasive methods. It also introduces other neuromonitoring techniques, such as cerebral autoregulation and oxygenation monitoring that provide additional information on the brain’s status.
In summary, this chapter offers a comprehensive historical perspective on TBI management, highlighting the key events and people that shaped its progress and the role of neuromonitoring in modern neurocritical care. It provides a valuable context for understanding the current state of the art and the future directions of TBI care.
... Intracranial pressure monitoring represented a major innovation, especially in managing patients with traumatic brain injury (TBI) and intraventricular hemorrhage. It was the Swedish neurosurgeon Nils Lundberg who first introduced ICP monitoring in 1965 [34], (Fig. 6) Lundberg had developed the technique in the 1950s at Lund University Hospital as part of his doctoral thesis [35]. ...
... Traumatic brain injury management also evolved in parallel with advances in critical care, neurosurgical techniques, brain imaging, and ICP monitoring. A key breakthrough came in 1960 when Lund introduced ventricular catheters, enabling the therapeutic drainage of CSF to be integrated into standard treatments for intracranial hypertension alongside osmotic agents and hyperventilation [34]. Subsequently, in 1971, bifrontal decompressive craniectomy was introduced to address refractory elevated ICP [84]. ...
Over the last century, significant milestones have been achieved in managing critical illness and diagnosing and treating neurological diseases. Building upon these milestones, the field of neurocritical care emerged in the 1980 and 1990 s at the convergence of critical care medicine and acute neurological treatment. This comprehensive review presents a historical account of key developments in neurocritical care in both the United States and Europe, with a special emphasis on German contributions. The scope of the review encompasses: the foundations of neurocritical care, including post-operative units in the 1920s and 30s, respiratory support during the poliomyelitis epidemics in the 40 and 50 s, cardiac and hemodynamic care in the 60 and 70 s, and stroke units in the 80 and 90 s; key innovations including cerebral angiography, computed tomography, and intracranial pressure and multi-modal monitoring; and advances in stroke, traumatic brain injury, cardiac arrest, neuromuscular disorders, meningitis and encephalitis. These advances have revolutionized the management of neurological emergencies, emphasizing interdisciplinary teamwork, evidence-based protocols, and personalized approaches to care.
... The first documented external ventricular drain (EVD) procedure was performed in 1744 by Claude-Nicolas Le Cat with a ventricular puncture and wick in place to drain CSF [93]. In 1960, Nils Lundberg systematically described ICP monitoring techniques and confirmed feasibility in 30 TBI patients [94,95]. Lundberg also characterized two types of ICP fluctuations which still hold clinical and prognostic significance today: Lundberg "A" waves-sustained increases in ICP to levels 9 50 mmHg for 5-20 min before rapid resolution, and Lundberg "B" waves-0.5-2 ...
... Lundberg also characterized two types of ICP fluctuations which still hold clinical and prognostic significance today: Lundberg "A" waves-sustained increases in ICP to levels 9 50 mmHg for 5-20 min before rapid resolution, and Lundberg "B" waves-0.5-2 Hz rhythmic oscillations to ICPs 20-30 mmHg above baseline but without sustained ICP increases [95]. These patterns represent significantly reduced intracranial compliance. ...
Purpose of review
The purposes of this narrative review are to (1) summarize a contemporary view of cerebral edema pathophysiology, (2) present a synopsis of current management strategies in the context of their historical roots (many of which date back multiple centuries), and (3) discuss contributions of key molecular pathways to overlapping edema endophenotypes. This may facilitate identification of important therapeutic targets.
Recent findings
Cerebral edema and resultant intracranial hypertension are major contributors to morbidity and mortality following traumatic brain injury. Although Starling forces are physical drivers of edema based on differences in intravascular vs extracellular hydrostatic and oncotic pressures, the molecular pathophysiology underlying cerebral edema is complex and remains incompletely understood. Current management protocols are guided by intracranial pressure measurements, an imperfect proxy for cerebral edema. These include decompressive craniectomy, external ventricular drainage, hyperosmolar therapy, hypothermia, and sedation. Results of contemporary clinical trials assessing these treatments are summarized, with an emphasis on the gap between intermediate measures of edema and meaningful clinical outcomes. This is followed by a brief statement summarizing the most recent guidelines from the Brain Trauma Foundation (4th edition). While many molecular mechanisms and networks contributing to cerebral edema after TBI are still being elucidated, we highlight some promising molecular mechanism-based targets based on recent research including SUR1-TRPM4, NKCC1, AQP4, and AVP1.
Summary
This review outlines the origins of our understanding of cerebral edema, chronicles the history behind many current treatment approaches, and discusses promising molecular mechanism-based targeted treatments.
... Key words -Accuracy -External ventricular drain -ICP -Intracranial pressure -Neurocritical care -Pressure transducer -Traumatic brain injury Abbreviations and Acronyms eICP: Externally transduced intracranial pressure FVC: Flex ventricular catheter ICP: Intracranial pressure iICP: Intracranially transduced intracranial pressure TBI: Traumatic brain injury The advent of ICP monitoring was originally pioneered by Janny and Guilliaume in 1951. 7 This was further expanded upon by the use of an intraventricular pressure monitor in patients with TBI by Lundberg in 1965. 8 Subsequently, several types of ICP measuring devices have been developed, including the subarachnoid screw, subdural cup catheter, extradural monitor, piezo-electric pressure transducers, fiberoptic catheter, and the catheter tip pressure transducer. ...
... 7 This was further expanded upon by the use of an intraventricular pressure monitor in patients with TBI by Lundberg in 1965. 8 Subsequently, several types of ICP measuring devices have been developed, including the subarachnoid screw, subdural cup catheter, extradural monitor, piezo-electric pressure transducers, fiberoptic catheter, and the catheter tip pressure transducer. 9 One of the most commonly used ICP monitoring devices remains the intraventricular catheter because of its cost-effectiveness, relative accuracy, and its ability to drain and sample cerebrospinal fluid. ...
Background:
Intracranial pressure monitoring remains the foundation for prevention of secondary injury after traumatic brain injury and is most commonly performed using an external ventricular drain or intraparenchymal pressure monitor. The Integra Flex ventricular catheter combines an external ventricular catheter with a pressure transducer embedded in the tip of the catheter to allow continuous pressure readings while simultaneously draining cerebrospinal fluid. Discrepancies between measurements from the continuously reported internal pressure transducer and intermittently assessed and externally transduced ventricular drain prompted an analysis and characterization of pressures transduced from the same ventricular source.
Methods:
More than 500 hours of high-resolution (125 Hz) continuous recordings were manually reviewed to identify 73 hours of simultaneous measurements (clamped external ventricular drain) from internal and external transducers in patients with traumatic brain injury.
Results:
A significant positive bias was found in pressure readings obtained from external relative to internal measurements. The 2 methods of measurement generally correlated poorly with each other and variably. Although proportional bias was found with Bland-Altman analysis, coherence revealed rare shifts in the external transducer as a major source of discrepancy. Infrequent changes in the 0-level of the external transducer were found to be the primary source of discrepancy. Relative to the observed differences, no significant trend was observed over time between the 2 modalities.
Conclusions:
This study suggests that the internal pressure transducer may be a more reliable estimate of intracranial pressure relative to bedside external transducers due to the inherent behavioral requirement of leveling.
... 2,3 This was because low-evidence levels support establishing an ICP value that suits everyone. 2 The pioneer studies of Lundberg et al, 4 Langfitt et al, 5 and Miller et al 6 provided insights on the noxious thresholds for ICP. 7 It was suggested that a warning sign starts at around 15 mm Hg, whereas the current guidelines from the Brain Trauma Foundation consider refractory intracranial hypertension (IH) when ICP levels are sustained >22 mm Hg. 8 This predetermination for ICP thresholds, although valid, should serve more as an orientation than a guideline to be strictly observed, as the harmful "dose of IH" may vary between patients and within the same subject during his or her care. ...
Background:
Intracranial pressure (ICP) management based on predetermined thresholds is not accurate in light of recent research on cerebrovascular physiology. Interpersonal and intrapersonal variations will lead ICP elevations to reach individualized thresholds for intracranial compliance impairment from one subject to another. Therefore reuniting the modern techniques of neuromonitoring besides ICP enables practitioners to have a more whole picture in anticipating neuro worsening and improving timing in decision making.
Methods:
Brief literature review.
Results:
For the severely brain-injured patient, current evidence indicates a personalized and physiology-based multimodal monitoring care to be required rather than decision making according to ICP predetermined cut-offs.
Conclusions:
The authors' point of view is of particular importance for regions with resource heterogeneity and scarcity, where ICP monitoring is not available for all those in need and noninvasive techniques may provide a surrogate approach. If physicians who deal with acute-brain-injured patients in lower-resource areas understand that several tools besides ICP may improve their practice, it is possible to reduce acute brain injury morbimortality.
... Intracranial pressure monitoring ICP monitoring was first described by Lundberg and colleagues in 1964 and has since become the most widely employed invasive monitoring technique with the largest amount of supporting data (4,63). Elevations in ICP are directly related to excess mortality and poor neurologic outcomes, likely through destructive mechanical forces as well as reduced cerebral perfusion leading to ischemia and oligemia within vulnerable brain parenchyma (32, [64][65][66]. ...
Given the complexity of cerebral pathology in patients with acute brain injury, various neuromonitoring strategies have been developed to better appreciate physiologic relationships and potentially harmful derangements. There is ample evidence that bundling several neuromonitoring devices, termed “multimodal monitoring,” is more beneficial compared to monitoring individual parameters as each may capture different and complementary aspects of cerebral physiology to provide a comprehensive picture that can help guide management. Furthermore, each modality has specific strengths and limitations that depend largely on spatiotemporal characteristics and complexity of the signal acquired. In this review we focus on the common clinical neuromonitoring techniques including intracranial pressure, brain tissue oxygenation, transcranial doppler and near-infrared spectroscopy with a focus on how each modality can also provide useful information about cerebral autoregulation capacity. Finally, we discuss the current evidence in using these modalities to support clinical decision making as well as potential insights into the future of advanced cerebral homeostatic assessments including neurovascular coupling.
... • A-waves, which Lundberg also denominated as "plateau waves", present a substantial steep up-slope increase in intracranial pressure values for at least 5 minutes, followed by a steep down-slope decrease to almost normal levels [13][14][15] . They are usually accompanied by clinical signs of distress on examination. ...
Introduction Intracranial pressure (ICP) monitoring and analysis are techniques that are, each year, applied to millions of patients with pathologies with million of patients annually. The detection of the so called A and B-waves, and the analysis of subtle changes in C-waves, which are present in ICP waveform, may indicate decreased intracranial compliance, and may improve the clinical outcome. Despite the advances in the field of computerized data analysis, the visual screening of ICP continues to be the means principally employed to detect these waves. To the best of our knowledge, no review study has addressed automated ICP analysis in sufficient detail and a need to research the state of the art of ICP analysis has, therefore, been identified.
Methodology This paper presents a systematic mapping study to provide answers to 7 research questions: publication time, venue and source trends, medical tasks undertaken, research methods used, computational systems developed, validation methodology, tools and systems employed for evaluation and research problems identified. An ICP software prototype is presented and evaluated as a consequence of the results.
Results 23 papers, published between 1990 and 2020, were selected from 6 online databases. After analyzing these papers, the following information was obtained: diagnosis and monitoring medical tasks were addressed to the same extent, and the main research method used was evaluation research. Several computational systems were identified in the papers, the main one being image classification, while the main analysis objective was single pulse analysis. Correlation with expert analysis was the most frequent validation method, and few of the papers stated the use of a published dataset. Few authors referred to the tools used to build or evaluate the proposed solutions. The most frequent research problem was the need for new analysis methods. These results have inspired us to propose a software prototype with which provide an automated solution that integrates ICP analysis and monitoring techniques.
Conclusions The papers in this study were selected and classified with regard to ICP automated analysis methods. Several research gaps were identified, which the authors of this study have employed as a based on which to recommend future work. Furthermore, this study has identified the need for an empirical comparison between methods, which will require the use and development of certain standard metrics. An in-depth analysis conducted by by means of systematic literature review is also required. The software prototype evaluation provided positive results, showing that the prototype may be a reliable system for A-wave detection.
... Lundberg a montré dès 1960 que la pression intracrânienne (PIC) pouvait atteindre des valeurs très élevées et considérablement variables dans le temps après un TCG et que cette augmentation ne pouvait pas être prédite par une surveillance basée uniquement sur l'examen clinique [22,23]. C'est dire l'intérêt d'un monitorage cérébral continu par voie ventriculaire ou parenchymateuse permettant un diagnostic précoce et fiable de l'HTIC. ...
Objective:
To determine the severity factors in severe traumatic brain injuries.
Methods:
A prospective descriptive study of severe head injuries admitted to the emergency department at Ibn Tofail Hospital at the University Hospital of Marrakesh over a period of six months from May to October 2015. The following data was collected: circumstances, clinical, biology, radiology, treatment and evolution.
Results:
One hundred and nineteen patients with severe traumatic brain injury were collected (101 males, 84,9%). The mean age was 37,73±15,7 years. Road accidents were the most common cause representing 84%. The median Glasgow coma scale (GCS) was 7±3. We noted 36 cases (30,3%) of anisocoria, 32 cases (26,9%) of bilateral mydriasis and 72 cases (60,5%) of hypoxia. Cerebral contusions (66,1%) and meningeal hemorrhage (66,6%) were the most frequent lesions on CT. Forty-seven patients (42%) had stage VI Marshall lesions. Twenty-four patients (20.1%) required a neurosurgical intervention, 12 extradural hematoma evacuations and 10 craniocerebral wounds. Mortality was 64.7% (77 deaths), the main cause was neurological (64,9%). In the latter group, we observed more frequently an older age (p = 0.00001), a management delay (p = 0.011), a low initial GCS (p = 0.000001), a bilateral nonreactive mydriasis (p = 0.0001), a hypoxia (p = 0.0002), a subarachnoid hemorrhage (p = 0.008), a high Marshall score (p = 0.017) and an anemia (p = 0.046).
Conclusion:
Head trauma is a public health problem. The victims are young, and the sequelae are frequently disabling. Several parameters are associated with a poorer prognosis including age, neurological state and the initial delay in management.
... ICP variations have generated interest since the development of ICP monitoring in the NIC [28]. For example, Lundberg identified type A waves (plateau waves) with amplitudes above 50 mm Hg with a duration above 5 min at low frequencies and type B waves with smaller amplitudes around 5 mm Hg but higher frequencies around 1-2 waves/minute [29]. According to the initial theory, both of these wave types are caused by cerebral vessels reacting to unstable blood pressure, leading to variations in CBV and ICP [30,31]. ...
Purpose
High intracranial pressure variability (ICPV) is associated with favorable outcome in traumatic brain injury, by mechanisms likely involving better cerebral blood flow regulation. However, less is known about ICPV in aneurysmal subarachnoid hemorrhage (aSAH). In this study, we investigated the explanatory variables for ICPV in aSAH and its association with delayed cerebral ischemia (DCI) and clinical outcome.
Methods
In this retrospective study, 242 aSAH patients, treated at the neurointensive care, Uppsala, Sweden, 2008–2018, with ICP monitoring the first ten days post-ictus were included. ICPV was evaluated on three time scales: (1) ICPV-1 m—ICP slow wave amplitude of wavelengths between 55 and 15 s, (2) ICPV-30 m—the deviation from the mean ICP averaged over 30 min, and (3) ICPV-4 h—the deviation from the mean ICP averaged over 4 h. The ICPV measures were analyzed in the early phase (day 1–3), in the early vasospasm phase (day 4–6.5), and the late vasospasm phase (day 6.5–10).
Results
High ICPV was associated with younger age, reduced intracranial pressure/volume reserve (high RAP), and high blood pressure variability in multiple linear regression analyses for all ICPV measures. DCI was associated with reduced ICPV in both vasospasm phases. High ICPV-1 m in the post-ictal early phase and the early vasospasm phase predicted favorable outcome in multiple logistic regressions, whereas ICPV-30 m and ICPV-4 h in the late vasospasm phase had a similar association.
Conclusions
Higher ICPV may reflect more optimal cerebral vessel activity, as reduced values are associated with an increased risk of DCI and unfavorable outcome after aSAH.
... Invasive ICP monitoring was introduced in the 1950s by Guillaume (5), further developed in the 1960s by Lundberg (6), and has ever since been used in NIC (Tables 1, 2, Figure 1). Over the years, the definition of what ICP threshold dichotomizes acceptable and dangerous ICP elevation has been extensively debated (7,13,14), and the value of ICP monitoring has also been questioned (15). ...
Neurointensive care (NIC) has contributed to great improvements in clinical outcomes for patients with severe traumatic brain injury (TBI) by preventing, detecting, and treating secondary insults and thereby reducing secondary brain injury. Traditional NIC management has mainly focused on generally applicable escalated treatment protocols to avoid high intracranial pressure (ICP) and to keep the cerebral perfusion pressure (CPP) at sufficiently high levels. However, TBI is a very heterogeneous disease regarding the type of injury, age, comorbidity, secondary injury mechanisms, etc. In recent years, the introduction of multimodality monitoring, including, e.g., pressure autoregulation, brain tissue oxygenation, and cerebral energy metabolism, in addition to ICP and CPP, has increased the understanding of the complex pathophysiology and the physiological effects of treatments in this condition. In this article, we will present some potential future approaches for more individualized patient management and fine-tuning of NIC, taking advantage of multimodal monitoring to further improve outcome after severe TBI.
... Más tarde, en 1965 se aplicó la experiencia de Lundberg en medir la presión intracraneal en pacientes con trauma craneoencefálico severo y se describió una serie de 30 casos de pacientes, los cuales fueron exitosamente monitorizados. 22,23 Desde 1960 con Lundberg, la derivación ventricular externa se considera el estándar de oro para el monitoreo de la presión intracraneal. 13 La elevación de la PIC es un fenómeno frecuente en los pacientes con trauma craneoencefálico, en el TCE grave se reporta entre 50 y 75% de los pacientes. ...
Introducción:
El trauma craneoencefálico es una causa importante de muerte y secuelas en nuestro país. La causa principal de muerte para estos pacientes es el aumento de la presión intracraneal. Existen diferentes métodos de monitorización de la presión intracraneal, puede ser por métodos invasivos y no invasivos. Entre los métodos no invasivos destaca por su accesibilidad la medición de la vaina del nervio óptico por ultrasonografía a la cabecera del paciente. Nuestro estudio pretende encontrar la distancia adecuada en milímetros a partir del globo ocular con la cual la medición del diámetro de la vaina del nervio óptico por ultrasonografía es más precisa si se compara con la medición en un estudio de tomografía simple de cráneo.
Material y métodos:
Se realizó un estudio de tipo observacional, prospectivo, transversal y analítico entre pacientes que ingresaran al Servicio de Terapia Intensiva Neurológica del Hospital General de Ecatepec Las Américas y que cumplieran con los criterios de ingreso en el periodo comprendido entre el 1o de noviembre de 2018 y el 31 de enero de 2019. Se compararon las medidas del diámetro de la vaina del nervio óptico a 3, 6 y 9 mm de cada globo ocular por ultrasonografía contra las medidas a las mismas distancias por tomografía simple de cráneo de cada uno de los pacientes.
Resultados:
No se encontró diferencia estadísticamente significativa al comparar las mediciones por ultrasonografía contra tomografía simple de cráneo en ninguna de las tres distancias establecidas (3, 6 y 9 mm) con una p > 0.05 en todos los casos. La distancia a la cual se encontró una menor diferencia entre las medidas fue a 3 mm a partir del globo ocular, esto sin significancia estadística. El trauma craneoencefálico en la población estudiada afecta principalmente a hombres jóvenes en edad productiva. La lesión que se encontró con mayor frecuencia en los estudios de tomografía simple de cráneo de los pacientes estudiados fue la hemorragia subaracnoidea.
Conclusiones:
La medición de la vaina del nervio óptico a 3, 6 y 9 mm a partir del globo ocular por ultrasonografía no muestra diferencia estadísticamente significativa si la comparamos con la medición de la vaina del nervio óptico mediante tomografía simple de cráneo en pacientes con trauma craneoencefálico severo. Sin embargo, la distancia que demuestra una menor diferencia entre ambas medidas es a 3 mm, la cual es la distancia ya establecida para realizar la medición en la bibliografía actual.
... PRx did not show any correlation with age, which is surprising, as significant correlation may be seen in anesthetized and ventilated patients after traumatic brain injury 9,20 . An additional similar correlation was shown between age and dysautoregulation in patients undergoing non-neurosurgical elective surgery. ...
Introduction
Normal pressure hydrocephalus (NPH) is not simply the result of a disturbance in cerebrospinal fluid (CSF) circulation, but often includes cardiovascular comorbidity and abnormalities within the cerebral mantle. In this study, we have examined the relationship between the global autoregulation pressure reactivity index (PRx), the profile of disturbed CSF circulation and pressure-volume compensation, and their possible effects on outcome after surgery.
Materials and methods
We studied a cohort of 131 patients, investigated for possible NPH. Parameters describing CSF compensation and circulation were calculated during the cerebrospinal fluid (CSF) infusion test and PRx was calculated from CSF pressure and arterial pressure recordings. A simple scale was used to mark the patients’ outcome 6 months after surgery (improvement, temporary improvement, and no improvement).
Results
PRx was negatively correlated with R out (R=−0.18; p=0.044); patients with normal CSF circulation tended to have worse autoregulation. The correlation for patients who were surgically-managed (N=83) was: R=−0.28; p=0.03, and stronger in patients who improved after surgery (N=64; R=−0.36; p=0.03). In patients who did not improve, the correlation was not significantly different from zero (N= 19; R=0.17; p=0.15). There was a trend towards higher values for PRx in non-responders than in responders (PRx =0.16+/− 0.04 vs 0.09 +/−0.02 respectively; p=0.061), associated with higher MAP values (107.2+/−8.2 in non-responders vs 89.5+/−3.5 in responders; p=0.195). The product of MAP* (1+PRx), proposed as a measure of combined arterial hypertension and deranged autoregulation, showed a significant association with outcome (greater value in non-responders; p=0.013).
Conclusion
Autoregulation proves to associate with cerebrospinal fluid circulation, and appears strongest in shunt responders. Outcome following CSF diversion is possibly most favorable when CSF outflow resistance is increased and global cerebral autoregulation is intact, in combination with arterial normotension.
... In addition to the pulse component of the ICP waveform, the ICP signal also oscillates over slower timescales. The ICP signal can be decomposed into frequency domain components based on contributing sources (8,11,12) (Figure 2). The pulse waveform described above is related to the cardiac cycle and has a frequency band of 1-1.3 Hz. ...
Continuous intracranial pressure (ICP) monitoring is a cornerstone of neurocritical care after severe brain injuries such as traumatic brain injury and acts as a biomarker of secondary brain injury. With the rapid development of artificial intelligent (AI) approaches to data analysis, the acquisition, storage, real-time analysis, and interpretation of physiological signal data can bring insights to the field of neurocritical care bioinformatics. We review the existing literature on the quantification and analysis of the ICP waveform and present an integrated framework to incorporate signal processing tools, advanced statistical methods, and machine learning techniques in order to comprehensively understand the ICP signal and its clinical importance. Our goals were to identify the strengths and pitfalls of existing methods for data cleaning, information extraction, and application. In particular, we describe the use of ICP signal analytics to detect intracranial hypertension and to predict both short-term intracranial hypertension and long-term clinical outcome. We provide a well-organized roadmap for future researchers based on existing literature and a computational approach to clinically-relevant biomedical signal data.
... Of the ones most commonly used, the most important appear to be ICP and cerebral perfusion pressure (CPP). Since the landmark paper by Lundberg,5 in which the clinical use of ICP monitoring was first demonstrated, it has become a standard procedure in the management of severely head-injured patients. There exists a large body of work on both the methods of measurement and their usefulness in clinical management. ...
Introduction Traumatic brain injury (TBI) is one of the leading causes of mortality and disability worldwide, and optimizing the management of these patients is a continuing challenge. Intraoperative intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were evaluated for use as prognostic indicators after surgery for severe TBI. Although ICP and CPP monitoring is standard postsurgery treatment for TBI, very few studies have reported the use of ICP and CPP values monitored during surgery.
Objectives The objectives of this study were to evaluate the use of intraoperative ICP and CPP values as prognostic indicators and as subjective guidelines for managing severe TBI.
Materials and methods All patients with severe TBI who underwent surgical decompression and ICP monitoring intraoperatively were included in our study from 2017 to 2018. We measured ICP and CPP values after creation of the first burr hole, after hematoma evacuation, and after wound closure.
Results From the analysis of receiver-operated characteristic (ROC) curves, we observed that ICP initial (cutoff > 28 mm Hg) and CPP initial (cutoff < 44.5 mm Hg) are the best predictors of unfavorable outcomes. Favorable outcome (Glasgow outcome scale [GOS] 4 and 5) and unfavorable outcome (GOS 1–3) after 6 months were achieved in 64.1 and 35.8% of patients, respectively. There was significant difference between the ICP and CPP values which are measured after the first burrhole, after hematoma evacuation, and after scalp closure in both favorable and unfavorable outcomes. The highest positive Pearson’s correlation coefficient is found between GOS and ICP and CPP after first burr hole.
Conclusion Monitoring ICP and CPP during surgery improves management in patients with severe TBI and provides an early prognostic indicator in such patients.
... The first data on invasive measurement of ICP were published by Guillaume and Janny in 1951 (12), and the first comprehensive analysis of ICP curve morphology was performed in patients with probable space occupying lesions by Lundberg in 1960 (13) and in patients with TBI in 1965 (14). The measurements were obtained through a transducer coupled to an external ventricular drain (EVD). ...
Purpose of Review: Monitoring of intracranial pressure (ICP) is an important and integrated part of the treatment algorithm for children with severe traumatic brain injury (TBI). Guidelines often recommend ICP monitoring with a treatment threshold of 20 mmHg. This focused review discusses; (1) different ICP technologies and how ICP should be monitored in pediatric patients with severe TBI, (2) existing evidence behind guideline recommendations, and (3) how we could move forward to increase knowledge about normal ICP in children to support treatment decisions.
Summary: Current reference values for normal ICP in adults lie between 7 and 15 mmHg. Recent studies conducted in “pseudonormal” adults, however, suggest a normal range below this level where ICP is highly dependent on body posture and decreases to negative values in sitting and standing position. Despite obvious physiological differences between children and adults, no age or body size related reference values exist for normal ICP in children. Recent guidelines for treatment of severe TBI in pediatric patients recommend ICP monitoring to guide treatment of intracranial hypertension. Decision on ICP monitoring modalities are based on local standards, the individual case, and the clinician's choice. The recommended treatment threshold is 20 mmHg for a duration of 5 min. Both prospective and retrospective observational studies applying different thresholds and treatment strategies for intracranial hypertension were included to support this recommendation. While some studies suggest improved outcome related to ICP monitoring (lower rate of mortality and severe disability), most studies identify high ICP as a marker of worse outcome. Only one study applied age-differentiated thresholds, but this study did not evaluate the effect of these different thresholds on outcome. The quality of evidence behind ICP monitoring and treatment thresholds in severe pediatric TBI is low and treatment can potentially be improved by knowledge about normal ICP from observational studies in healthy children and cohorts of pediatric “pseudonormal” patients expected to have normal ICP. Acceptable levels of ICP − and thus also treatment thresholds—probably vary with age, disease and whether the patient has intact cerebral autoregulation. Future treatment algorithms should reflect these differences and be more personalized and dynamic.
... Traditionally, ICPV in terms of type A and B waves have been considered pathological [18,23]. However, we and others have earlier demonstrated that high ICPV is associated with survival and favorable outcome [3][4][5]. ...
It was recently found in traumatic brain injury (TBI) that ICP variability (ICPV) predicted favorable outcome. We hypothesized that ICPV may depend on intracranial compliance, unstable blood pressure and cerebral vasomotion. In this study, we aimed to further investigate the explanatory variables for ICPV and its relation to outcome. Data from 362 TBI patients were retrospectively analyzed day 2 to 5 post-injury. ICPV was evaluated in three ways. First, variability in the sub-minute time interval (similar to B waves) was calculated as the amplitude of the ICP slow waves using a bandpass filter, limiting the analysis to oscillations of 55 to 15 s (ICP AMP 55–15). The second and third ICPV measures were calculated as the deviation from the mean ICP averaged over 30 min (ICPV-30m) and 4 h (ICPV-4h), respectively. All ICPV measures were associated with a reduced intracranial pressure/volume state (high ICP and RAP) and high blood pressure variability in multiple linear regression analyses. Higher ICPV was associated with better pressure reactivity in the univariate, but not the multiple analyses. All ICPV measures were associated with favorable outcome in univariate analysis, but only ICP AMP 55–15 and ICPV-30m did so in the multiple logistic regression analysis. Higher ICPV can be explained by a reduced intracranial compliance and variations in cerebral blood volume due to the vessel response to unstable blood pressure. As ICP AMP 55–15 and ICPV-30m independently predicted favorable outcome, it may represent general cerebral vessel activity, associated with better cerebral blood flow regulation and less secondary insults.
... The added benefit conferred by EVDs, by coupling ventricular pressure monitoring and drainage, which was pioneered by Franklin Robinson in 1948, further encouraged EVD use in patients with non-traumatic neurological conditions, such as subarachnoid haemorrhage, brain tumours, and Reye's syndrome characterised by cerebral oedema [17,21,22]. The use of EVDs for ICP monitoring in patients with severe head injury, and the relationship between ICP and neurological outcomes, were also increasingly reported in case series [23][24][25][26]. This led to the wide adoption of EVDs in TBI management protocols, as an ICP monitor and CSF drainage apparatus [22]. ...
External ventricular drains (EVDs) are commonly used in neurosurgery in different conditions but frequently in the management of traumatic brain injury (TBI) to monitor and/or control intracranial pressure (ICP) by diverting cerebrospinal fluid (CSF). Their clinical effectiveness, when used as a therapeutic ICP-lowering procedure in contemporary practice, remains unclear. No consensus has been reached regarding the drainage strategy and optimal timing of insertion. We review the literature on EVDs in the setting of TBI, discussing its clinical indications, surgical technique, complications, clinical outcomes, and economic considerations.
... The occurrence of these phenomena are useful in clinical practice in that these alert the neurophysician to initiate ICP control measures on an urgent basis. It is pertinent to note here that increased ICP can produce characteristic waveform variously classified by Lundberg into A, B and C waves [12] . ...
Intracranial pressure monitoring (ICP) is based on the doctrine proposed by Monroe and Kellie centuries ago. With the advancement of technology and science, various invasive and non-invasive modalities of monitoring ICP continue to be developed. An ideal monitor to track ICP should be easy to use, accurate, reliable, reproducible, inexpensive and should not be associated with infection or haemorrhagic complications. Although the transducers connected to the extra ventricular drainage continue to be Gold Standard, its association with the likelihood of infection and haemorrhage have led to the search for alternate non-invasive methods of monitoring ICP. While Camino transducers, Strain gauge micro transducer based ICP monitoring devices and the Spiegelberg ICP monitor are the emerging technology in invasive ICP monitoring, optic nerve sheath diameter measurement, venous opthalmodynamometry, tympanic membrane displacement, tissue resonance analysis, tonometry, acoustoelasticity, distortion-product oto-acoustic emissions, trans cranial doppler, electro encephalogram, near infra-red spectroscopy, pupillometry, anterior fontanelle pressure monitoring, skull elasticity, jugular bulb monitoring, visual evoked response and radiological based assessment of ICP are the non-invasive methods which are assessed against the gold standard.
... The emergence of modern neurosurgery at the beginning of the twentieth century led to a rapidly evolving understanding of neuroanatomy and neurophysiology. These advances, along with progress in material science, paved the way for the first ventricular catheter-based ICP monitoring studies in acute brain injury patients (30,32,33), culminating in the milestone studies by Lundberg and colleagues, first in brain tumor patients (20) and later in TBI cases (34). These studies established the critical role of ICP in the pathophysiology of acute brain injury and challenged engineers and physicians to develop and test new and reliable techniques for ICP measurement for use in the emerging field of intensive care. ...
Patients with acute brain injuries tend to be physiologically unstable and at risk of rapid and potentially life-threatening decompensation due to shifts in intracranial compartment volumes and consequent intracranial hypertension. Invasive intracranial pressure (ICP) monitoring therefore remains a cornerstone of modern neurocritical care, despite the attendant risks of infection and damage to brain tissue arising from the surgical placement of a catheter or pressure transducer into the cerebrospinal fluid or brain tissue compartments. In addition to ICP monitoring, tracking of the intracranial capacity to buffer shifts in compartment volumes would help in the assessment of patient state, inform clinical decision making, and guide therapeutic interventions. We review the anatomy, physiology, and current technology relevant to clinical management of patients with acute brain injury and outline unmet clinical needs to advance patient monitoring in neurocritical care.
... Currently, the gold standard technique for direct measurement of ICP is by an intraventricular catheter. 29 However, it is invasive and carries significant risks such as infection, hemorrhage, catheter blockage, and malposition. 30 In addition, availability of this technique is usually limited to neurosurgical centers and often restricted to neurocritical care units. ...
Background:
Transorbital ultrasonographic measurement of optic nerve sheath diameter (ONSD) is an important technique for bedside assessment of raised intracranial pressure (ICP). However, developing competency for this clinical skill requires practice scans on both normal subjects and patients with raised ICP. The aim of this study is to develop a high-fidelity training model capable of measuring dynamic changes in ONSD and to test the reliability and reproducibility of the model at different simulated ICP values.
Materials and methods:
We designed and developed a high-fidelity training model for dynamic ONSD measurement using a hemispherical table tennis ball, mounted on a 3.0-mm pediatric microcuffed endotracheal tube (ETT). Two independent investigators then performed a randomized blinded study to assess the reliability and reproducibility of the model. A total of 30 ONSD measurements (10 measurements each for 3 ETT cuff volumes of 0.1, 0.2, and 0.3 mL, simulating an ONSD of a normal, borderline, and raised ICP, respectively) were performed by each investigator. Intraclass correlation coefficients and Bland-Altman plots were calculated to analyze the level of agreement between the investigators.
Results:
Our model was able to provide dynamic changes in ONSD secondary to ETT cuff volume changes. Small increments of 0.1 mL cuff volume changes produced immediate changes in ONSD that are similar to those observed in patients. The median interobserver difference in ONSD was 0.3 mm (interquartile range, 0. to 0.4 mm). Intraclass correlation coefficient was 0.89, 0.89, and 0.90 for 0.1, 0.2, and 0.3 mL ETT cuff volumes, respectively.
Conclusions:
We have developed a clinically relevant model capable of simulating changes in ONSD in patients with normal and raised ICP. This model could be a valuable training tool to gain scanning experience in optic nerve ultrasonography, and improve operators' technical abilities.
Intracranial pressure (ICP) is the staple of neurocritical care as it is an indicator of dysfunctional intracranial compliance. Intracranial disease or pathology involves complex pathophysiological cascades of events that alter cerebral blood flow, cerebral oxygenation, and metabolism beyond intracranial pressure. Management of elevated ICP is critical for improved clinical outcome. ICP measurement thus constitutes an essential part of multimodal monitoring and is by far the most applied monitoring parameter ICP is measured in diverse neurological conditions. This chapter discusses physiological and pathological trends of ICP in relation to intracranial compliance and various invasive and non invasive techniques of ICP measurement.
Introduction
Hemorrhagic stroke may cause changes in intracranial pressure (ICP) and cerebral perfusion pressure (CPP), which may influence the prognosis of patients. The aim of this study was to investigate the relationship between early ICP, CPP, and 28-day mortality in the intensive care unit (ICU) of patients with hemorrhagic stroke.
Patients and methods
A retrospective study was performed using the Medical Information Mart for Intensive Care (MIMIC-IV) and the eICU Collaborative Research Database (eICU-CRD), including hemorrhagic stroke patients in the ICU with recorded ICP monitoring. The median values of ICP and CPP were collected for the first 24 h of the patient’s monitoring. The primary outcome was 28-day ICU mortality. Multivariable Cox proportional hazards models were used to analyze the relationship between ICP, CPP, and 28-day ICU mortality. Restricted cubic regression splines were used to analyze nonlinear relationships.
Results
The study included 837 patients with a 28-day ICU mortality rate of 19.4%. Multivariable analysis revealed a significant correlation between early ICP and 28-day ICU mortality (HR 1.08, 95% CI 1.04–1.12, p < 0.01), whereas early CPP showed no correlation with 28-day ICU mortality (HR 1.00, 95% CI 0.98–1.01, p = 0.57), with a correlation only evident when CPP < 60 mmHg (HR 1.99, 95% CI 1.14–3.48, p = 0.01). The study also identified an early ICP threshold of 16.5 mmHg.
Discussion and conclusion
Early ICP shows a correlation with 28-day mortality in hemorrhagic stroke patients, with a potential intervention threshold of 16.5 mmHg. In contrast, early CPP showed no correlation with patient prognosis.
Continuous monitoring of mean intracranial pressure (ICP) has been an essential part of neurocritical care for more than half a century. Cerebrospinal pressure–volume compensation, i.e., the ability of the cerebrospinal system to buffer changes in volume without substantial increases in ICP, is considered an important factor in preventing adverse effects on the patient’s condition that are associated with ICP elevation. However, existing assessment methods are poorly suited to the management of brain injured patients as they require external manipulation of intracranial volume. In the 1980s, studies suggested that spontaneous short-term variations in the ICP signal over a single cardiac cycle, called the ICP pulse waveform, may provide information on cerebrospinal compensatory reserve. In this review we discuss the approaches that have been proposed so far to derive this information, from pulse amplitude estimation and spectral techniques to most recent advances in morphological analysis based on artificial intelligence solutions. Each method is presented with focus on its clinical significance and the potential for application in standard clinical practice. Finally, we highlight the missing links that need to be addressed in future studies in order for ICP pulse waveform analysis to achieve widespread use in the neurocritical care setting.
Since its introduction in the 1960s, intracranial pressure (ICP) monitoring has become an indispensable tool in neurocritical care practice and a key component of the management of moderate/severe traumatic brain injury (TBI). The primary utility of ICP monitoring is to guide therapeutic interventions aimed at maintaining physiological ICP and preventing intracranial hypertension. The rationale for such ICP maintenance is to prevent secondary brain injury arising from brain herniation and inadequate cerebral blood flow. There exists a large body of evidence indicating that elevated ICP is associated with mortality and that aggressive ICP control protocols improve outcomes in severe TBI patients. Therefore, current management guidelines recommend a cerebral perfusion pressure (CPP) target range of 60–70 mm Hg and an ICP threshold of >20 or >22 mm Hg, beyond which therapeutic intervention should be initiated. Though our ability to achieve these thresholds has drastically improved over the past decades, there has been little to no change in the mortality and morbidity associated with moderate-severe TBI. This is a result of the “one treatment fits all” dogma of current guideline-based care that fails to take individual phenotype into account. The way forward in moderate-severe TBI care is through the development of continuously derived individualized ICP thresholds. This narrative review covers the topic of ICP monitoring in TBI care, including historical context/achievements, current monitoring technologies and indications, treatment methods, associations with patient outcome and multi-modal cerebral physiology, present controversies surrounding treatment thresholds, and future perspectives on personalized approaches to ICP-directed therapy.
Patients with severe traumatic brain injury (TBI) are usually intubated and mechanically ventilated with the use of sedative agents and muscle relaxants. Clinical monitoring in such patients is often impracticable. Intracranial pressure (ICP) monitoring is commonly used in many centers as a bedside tool to assess the neurological status. The alternate approach is regular clinical assessment and serial CT scans. This chapter evaluates the evidence behind the utility of an ICP-centered monitoring approach compared with the clinical and CT-based strategy.KeywordsTraumatic brain injuryICPIntracranial hypertension
Care for Complications After Catastrophic Brain Injury
Stroke is one of the most important and most feared conditions known to man. The threat of stroke is important to all people. What could be more devastating than to lose the ability to speak, move a limb, stand, talk, see, read, feel write or even think? This book brings together ideas, events and advances – the stories – before and during the 20th Century through the accounts of global experts in the field, many of them having been first-hand witnesses to progress. Focusing on selected stories of stroke, this book offers a readable summary of the most dramatic and extensive changes in knowledge about stroke and in caring for stroke patients. Of interest to anyone interested in neurosciences and for physicians caring for stroke patients, this book informs on moving forward, by looking to how we got to where we are.
When Werner Hacke, the 39-year-old newly appointed chair of neurology at the University of Heidelberg in Germany, strode into the 12-bed Neuro-Intensive Care Unit in 1987, it was the start of something new. Neurocritical care began in the 1980s with convergence of the evolution of critical care and advances in the diagnosis and management of severe brain injury. Although many people contributed to that convergence, three stand out: Allan Ropper at Massachusetts General Hospital (MGH), Dan Hanley at Johns Hopkins Hospital, and Werner Hacke. Bold, confident, and with a take-no-prisoners focus on aggressive treatment, Hacke was the embodiment of neurocritical care, especially for acute stroke. The roots of neurocritical care can be traced to the surgical wards of Johns Hopkins Hospital in Baltimore early in the twentieth century.
Although intracranial pressure (ICP) monitoring has been the mainstay of traumatic brain injury (TBI) management for decades, new understanding of TBI physiopathology calls for paradigm shifts. The complexity of TBI management precludes ICP being taken as an isolated value with a specific threshold. Multimodality monitoring is crucial to expanding our comprehension of individualized pathophysiology, allowing for a precise and tailored treatment approach. This article will review keys concepts to interpret and apply published ICP management guidelines and statements.
Objective:
Severe traumatic brain injury (TBI) is associated with intracranial hypertension (ICHTN). The Rotterdam CT score (RS) can predict clinical outcomes following TBI, but the relationship between the RS and ICHTN is unknown. The purpose of this study was to investigate clinical and radiological factors that predict ICHTN in patients with severe TBI.
Methods:
The authors performed a single-center retrospective review of patients who, between 2018 and 2021, had an intracranial pressure (ICP) monitor placed following TBI. Radiological and clinical characteristics related to the TBI and ICP monitoring were collected. The main outcome of interest was ICHTN, which was a dichotomous outcome (yes or no) defined on a per-patient basis as an ICP > 22 mm Hg that persisted for at least 5 minutes and required an escalation of treatment. ICHTN included both elevated opening pressure on initial monitor placement and ICP elevations later during hospitalization. Multivariate logistic regression was performed to determine variables associated with ICHTN. Diagnostic accuracy was evaluated using the area under the receiver operating characteristic curve (AUROC).
Results:
Seventy patients with severe TBI and an ICP monitor were included in this study. There was a predominance of male patients (94.0%), and the mean patient age was 40 years old. Most patients (67%) had an intraparenchymal catheter placed, whereas 33% of patients had a ventriculostomy catheter placed. In the multivariate logistic regression analysis, the RS was an independent predictor of ICHTN (OR 2.0, 95% CI 1.2-3.5, p = 0.014). No instances of ICHTN were observed in patients with an RS of 2 or less and no sulcal effacement. The AUROC of the RS and sulcal effacement was higher than the AUROC of the RS alone for predicting ICHTN (0.76 vs 0.71, p = 0.003, z-test).
Conclusions:
The RS was predictive of ICHTN in patients with severe TBI, and the diagnostic accuracy of the model was improved with the inclusion of sulcal effacement at the vertex on CT of the head. Patients with a low RS and no sulcal effacement are likely at low risk for the development of ICHTN.
Intracranial pressure (ICP) monitoring is now viewed as integral to the clinical care of many life-threatening brain insults, such as severe traumatic brain injury, subarachnoid hemorrhage, and malignant stroke. It serves to warn of expanding intracranial mass lesions, to prevent or treat herniation events as well as pressure elevation which impedes nutrient delivery to the brain. It facilitates the calculation of cerebral perfusion pressure (CPP) and the estimation of cerebrovascular autoregulatory status. Despite advancements in our knowledge emanating from a half century of experience with this technology, important controversies remain related even to fundamental aspects of ICP measurements, including indications for monitoring, ICP treatment thresholds, and management of intracranial hypertension. Here, we review the history of ICP monitoring, the underlying pathophysiology as well as current perspectives on why, when and how ICP monitoring is best used. ICP is typically assessed invasively but a number of emerging, non-invasive technologies with inherently lower risk are showing promise. In selected cases, additional neuromonitoring can be used to assist in the interpretation of ICP monitoring information and adapt directed treatment accordingly. Additional efforts to expand the evidence base relevant to ICP monitoring, related technologies and management remain a high priority in neurosurgery and neurocritical care.
This chapter explores the mathematical relationship between ICP, MAP, CPP, CBF, and CVR, and then delves into the ways intracranial pressure can be measured with bedside tools and neuroimaging. In the second half of the chapter. The chapter includes an explanation of the intracranial pressure tracing and the concept of Lundberg waves. In the third half of the chapter, the focus shifts to the 3-tier management strategy proposed by the Seattle Severe Traumatic Injury Consensus Conference to manage elevated intracranial pressure.KeywordsElevated intracranial pressureCerebral perfusion pressureHerniationPlateau pressuresMonro-Kellie doctrine
Learning objectives:
After studying this article, the participant should be able to: 1. Understand the craniofacial dysmorphology of craniosynostosis, and the variation of each type. 2. Identify the functional concerns and learn the rationale behind timing of operative intervention. 3. Approach each dysmorphology critically and identify the operative intervention needed to improve form and function 4. Understand and address the specific issues related to syndromic craniosynostosis and be able to delineate management plan.
Summary:
Craniosynostosis is a condition in which premature fusion of one or more cranial sutures lead to abnormal head shape and growth restriction of the brain. Nonsyndromic craniosynostosis occurs in isolation, and usually involves a single suture, whereas syndromic craniosynostosis may involve multiple sutures and is associated with extracraniofacial findings. Although surgical management can be similar, the treatment plan must take into consideration issues specific to the syndromes. This article aims to provide a concise overview of the authors' current understanding regarding the presentation, treatment principle, surgical option, and debates in craniosynostosis.
Brain harbors a unique ability to, figuratively speaking, shift its gears. During wakefulness, the brain is geared fully towards processing information and behaving, while homeostatic functions predominate during sleep. The blood-brain barrier establishes a stable environment that is optimal for neuronal function, yet the barrier imposes a physiological problem; transcapillary filtration that forms extracellular fluid in other organs is reduced to a minimum in brain. Consequently, the brain depends on a special fluid (the cerebrospinal fluid; CSF) that is flushed into brain along the unique perivascular spaces created by astrocytic vascular endfeet. We describe this pathway, coined the term glymphatic system, based on its dependency on astrocytic vascular endfeet and their adluminal expression of AQP4 water channels facing towards CSF-filled perivascular spaces. Glymphatic clearance of potentially harmful metabolic or protein waste products, such as amyloid-β is primarily active during sleep, when its physiological drivers, the cardiac cycle, respiration, and slow vasomotion, together efficiently propel CSF inflow along periarterial spaces. The brain's extracellular space contains an abundance of proteoglycans and hyaluronan, which provide a low-resistance hydraulic conduit that rapidly can expand and shrink during the sleep-wake cycle. We describe this unique fluid system of the brain, which meets the brain's requisites to maintain homeostasis similar to peripheral organs, considering the blood-brain-barrier and the paths for formation and egress of the CSF.
Severe traumatic brain injury is a common problem. Current practices focus on the importance of early resuscitation, transfer to high-volume centers, and provider expertise across multiple specialties. In the emergency department, patients should receive urgent intracranial imaging and consideration for tranexamic acid. Close observation in the intensive care unit environment helps identify problems, such as seizure, intracranial pressure crisis, and injury progression. In addition to traditional neurologic examination, patients benefit from use of intracranial monitors. Monitors gather physiologic data on intracranial and cerebral perfusion pressures to help guide therapy. Brain tissue oxygenation monitoring and cerebromicrodialysis show promise in studies.
Neural function is essential to human existence. Thus, loss of any neural element in the course of a critical illness represents a major loss to a given individual. Neurons or supporting elements may be lost in a small, virtually unnoticeable manner, perhaps manifest as cognitive or behavioral deficit, or there may be widespread selective neuronal loss or tissue infarction with more apparent and disabling deficits. Based on the notion that neural function is the essence of acceptable survival from critical illness, it is crucial for perioperative management to include considerations of neural viability and the impact and interactions of the primary diseases and therapeutics on the nervous system. There are numerous perioperative scenarios where a patient may present with neurologic dysfunction. In a general sense, these scenarios often involve ischemia, trauma, or neuroexcitation. Each of these, as they progressively worsen, at some point typically involve a period of decreased cerebral perfusion pressure (CPP), usually resulting from elevated intracranial pressure, eventually compromising cerebral blood flow sufficiently to produce permanent neuronal loss, infarction, and possibly brain death. A variety of biochemical pathways play a major role. Optimization of perioperative outcome after injury to the central nervous system (CNS) is a multifactorial process requiring skillful and well-informed anesthetic and critical care management. However, none of these interventions is risk-free, and extensive knowledge and expertise are very important to ensure a fine balance between the benefits and risks of specific interventions. By the end of this chapter, the anesthesia provider should have a general understanding of how to address the most commonly encountered complications in the acutely injured central nervous system.
Objectives:
Targets for treatment of raised intracranial pressure or decreased cerebral perfusion pressure in pediatric neurocritical care are not well defined. Current pediatric guidelines, based on traumatic brain injury, suggest an intracranial pressure target of less than 20 mm Hg and cerebral perfusion pressure minimum of 40-50 mm Hg, with possible age dependence of cerebral perfusion pressure . We sought to define intracranial pressure and cerebral perfusion pressure thresholds associated with inhospital mortality across a large single-center pediatric neurocritical care cohort.
Design:
Retrospective chart review.
Setting:
PICU, single quaternary-care center.
Patients:
Individuals receiving intracranial pressure monitoring from January 2012 to December 2016.
Interventions:
None.
Measurements and main results:
Intracranial pressure and cerebral perfusion pressure measurements from 262 neurocritical care patients (87 traumatic brain injury and 175 nontraumatic brain injury; 63% male; 8.3 ± 5.8 yr; mortality 11.1%). Mean intracranial pressure and cerebral perfusion pressure had area under the receiver operating characteristic curves of 0.75 and 0.64, respectively, for association of inhospital mortality. Cerebral perfusion pressure cut points increased with age (< 2 yr = 47, 2 to < 8 yr = 58 mm Hg, ≥ 8 yr = 73 mm Hg). In the traumatic brain injury subset, mean intracranial pressure and cerebral perfusion pressure had area under the receiver operating characteristic curves of 0.70 and 0.78, respectively, for association of inhospital mortality. Traumatic brain injury cerebral perfusion pressure cut points increased with age (< 2 yr = 45, 2 to < 8 yr = 57, ≥ 8 yr = 68 mm Hg). Mean intracranial pressure greater than 15 mm Hg, male sex, and traumatic brain injury status were independently associated with inhospital mortality (odds ratio, 14.23 [5.55-36.46], 2.77 [1.04-7.39], and 2.57 [1.03-6.38], respectively; all p < 0.05). Mean cerebral perfusion pressure less than 67 mm Hg and traumatic brain injury status were independently associated with inhospital mortality (odds ratio, 5.16 [2.05-12.98] and 3.71 [1.55-8.91], respectively; both p < 0.01). In the nontraumatic brain injury subset, mean intracranial pressure had an area under the receiver operating characteristic curve 0.77 with an intracranial pressure cut point of 15 mm Hg, whereas mean cerebral perfusion pressure was not predictive of inhospital mortality.
Conclusions:
We identified mean intracranial pressure thresholds, utilizing receiver operating characteristic and regression analyses, associated with inhospital mortality that is below current guidelines-based treatment targets in both traumatic brain injury and nontraumatic brain injury patients, and age-dependent cerebral perfusion pressure thresholds associated with inhospital mortality that were above current guidelines-based targets in traumatic brain injury patients. Further study is warranted to identify data-driven intracranial pressure and cerebral perfusion pressure targets in children undergoing intracranial pressure monitoring, whether for traumatic brain injury or other indications.
Compartment syndrome in its various forms is particularly challenging in resource-limited settings owing to the scarcity of data and the low awareness of workers practicing in these areas of the world. In suspected cases, confirmation of the diagnosis and management decisions are difficult in the absence of pressure-measuring devices. Two anatomical locations of compartment syndromes deserve special attention in these areas because of their relative frequency and their potentially heavy consequences: the lower limb and the abdomen. The strategy in resource-limited countries should be centered on early recognition based on purely clinical criteria and a reasonable timely decision for aponeurotomy. In the abdomen, all patients undergoing damage control laparotomy should be considered potential victims of acute compartment syndrome. General preventive measures are likely to heavily reduce the burden of abdominal compartment syndrome. In all other cases, management should be tailored towards organizing transfer towards an appropriate center.
Purpose:
Continuous EEG can potentially be used as real-time brain telemetry for the early detection of neurologic decline. Scant literature on EEG changes related to elevated intracranial pressure (ICP) limits its use in this context.
Methods:
Retrospective, observational case series of patients in whom we noted EEG changes correlating with a clinical concern for elevated ICP, measured or unmeasured.
Results:
We noted EEG changes of varying severity and duration correlating with either measured or unmeasured clinical concern for elevated ICP. In two patients with recurrent transient unresponsiveness (presumed from plateau waves), generalized rhythmic delta activity and attenuation of fast activity occurred 30 minutes before a clinical change. Elevated ICP in two patients, one related to progressive mass effect from infarctions, and the other to dialysis, correlated with generalized slowing and attenuation of fast activity up to 24 hours before clinical deterioration, leading to diffuse suppression. Two patients with intraventricular hemorrhage had cyclic patterns at ∼1 per minute and ∼6 per minute (similar frequency to described frequency of Lundberg B and C waves, respectively).
Conclusions:
Cyclic patterns and varying degrees of slowing and attenuation often preceded clinical deterioration associated with intracranial hypertension. Future systematic studies of EEG changes in this setting will facilitate early and noninvasive detection of elevated ICP.
Importance
Intracranial pressure (ICP) elevation is a compartment syndrome that impairs blood flow to the brain. Despite the importance of ICP values in neurocritical care, normal ICP values and the precise ICP threshold at which treatment should be initiated remain uncertain.
Objective
To refine our understanding of normal ICP values and determine the ICP threshold most strongly associated with outcome.
Design, Setting, and Participants
Prospective observational study (2004-2010), with outcomes determined at hospital discharge. The study included neurocritical care patients from a single level I trauma center, San Francisco General Hospital. Three hundred eighty-three patients had a traumatic brain injury with or without craniectomy; 140 patients had another indication for ICP monitoring. Consecutive patients were studied. Data analyses were completed between March 2015 and December 2019.
Exposures
Five hundred twenty-three ICP-monitored patients.
Main Outcomes and Measures
A computer system prospectively and automatically collected 1-minute physiologic data from patients in the intensive care unit during a 6-year period. Mean ICP was calculated, as was the proportion of ICP values greater than thresholds from 1 to 80 mm Hg in 1–mm Hg increments. The association between these measures and outcome was explored for various epochs up to 30 days from the time of injury. A principal component analysis was used to explore physiologic changes at various ICP thresholds, and elastic net regression was used to identify ICP thresholds most strongly associated with Glasgow Outcome Scale score at discharge.
Results
Of the 523 studied patients, 70.7% of studied patients were men (n = 370) and 72.1% had a traumatic brain injury (n = 377). A total of 4 090 964 1-minute ICP measurements were recorded for the included patients (7.78 years of recordings). Intracranial pressure values of 8 to 9 mm Hg were most commonly recorded and could possibly reflect normal values. The principal component analysis suggested state shifts in the physiome occurred at ICPs greater than 19 mm Hg and 24 mm Hg. Elastic net regression identified an ICP threshold of 19 mm Hg as most robustly associated with outcome when considering all neurocritical care patients, patients with TBI, and patients with TBI who underwent craniectomy. Intracranial pressure values greater than 19 mm Hg were associated with mortality, while lower values were associated with outcome in surviving patients.
Conclusions and Relevance
This study provides insight into what normal ICP values could be. An ICP threshold of 19 mm Hg was robustly associated with outcome in studied patients, although lower ICP values were associated with outcome in surviving patients.
The purpose of this retrospective study was to assess the genetic and phenotypic features of patients with craniofrontonasal syndrome (CFNS), and the implications of the condition for multidisciplinary management.
The subjects were 25 female patients with a mutation of EFNB1 , who presented to the Oxford Craniofacial Unit during a 38-year period. Medical records were reviewed for genetic and phenotypic information. Mean duration of follow-up was 12.6 years (range 0–30.7 years).
This study examines neurodevelopment in constituent parts, with specific reference to speech, language, and cognition in relation to genotype. Three children had deletions extending beyond the EFNB1 gene; the 2 with available data presented with speech, language, or cognitive delay. The remaining 25 patients had intragenic mutations of EFNB1. Of these 25, those assessed in detail showed variable difficulties with speech and language development; 57% had receptive language difficulties (n = 4/7) and 88% had expressive language difficulties (n = 8/9). 55% presented with speech difficulties (n = 6/11). 2/3 patients with abnormal hearing had speech difficulties; 4/5 with normal hearing had normal speech development. Cognitive assessments indicated that IQ is variable; with full scale IQ ranging from 69 to 100.
The complex, multifactorial presentation of patients with CFNS contributed to 41% (n = 7/17) of patients requiring additional educational support.
Our results demonstrated significant multidisciplinary input is required, including Speech and Language Therapy, Plastic and Reconstructive Surgery, Genetics, Ear, Nose and Throat, Maxillofacial, Orthodontic, Orthopaedic, Clinical Psychology and Orthoptic teams. The results of this study reinforce the importance of multi-disciplinary long-term follow-up of children with CFNS.
Intracranial pressure (ICP) monitoring has become an important tool in neurocritical care. Despite being used in ICUs all over the world, many are unfamiliar with its origins and the people and events that shaped the development of this technique. Herein, we provide a comprehensive historical review of the evolution of ICP monitoring, beginning with the earliest descriptions of the cerebrospinal fluid. We conducted a database search in PubMed, Google Scholar, and Google Books for relevant articles using the keywords “cerebrospinal fluid”, “intracranial pressure” and “monitoring”. Articles were further snowballed using reference lists of relevant papers. Although the earliest descriptions of the CSF date back several hundred years B.C., the history of ICP monitoring itself is not a long one. Alexander Monro and his student George Kellie laid the foundation of CSF physiology in the early 1800s through the Monro-Kellie doctrine. Their principles were later consolidated by John Abercrombie and Harvey Cushing. However, ten years earlier than Cushing’s work on CSF physiology, Hans Queckenstedt’s utilization of a lumbar needle to measure the pressure in the CSF marked the beginning of the era of ICP monitoring. Thenceforward, ICP monitoring technology underwent progressive improvements through the contributions of French scientists Guillaume and Janny, Swedish neurosurgeon Nils Lundberg, among others. Nowadays, ICP monitoring can be performed via direct and indirect methods using a potpourri of devices such as, but not limited to, subarachnoid bolts, microtransducer catheters and telemetric monitors. Nevertheless, despite advancements in ICP monitoring technology, the gold standard remains an extra-ventricular drain catheter connected to an external pressure transducer.
Secondary brain injury results from ischemia, tissue hypoxia, and a cascade of ongoing metabolic events. Neuromonitoring has evolved over the last two decades with the goal of preventing, detecting, and attenuating the damage from these secondary events. Typical monitored parameters include intracranial pressure (ICP) and cerebral perfusion pressure (CPP). Advanced multimodal monitoring includes monitoring of cerebral blood flow (CBF), brain tissue oxygenation (transcranial oximetry, jugular bulb oximetry, brain tissue oxygen tension), and brain metabolism (intracerebral microdialysis). In this chapter, we will review basic principles of brain physiology and the complex and dynamic interactions between these parameters. In the future, neuromonitoring will be supported by advanced signal processing and analysis that will enable clinicians to synthesize information and form hypotheses that best explain the current situation. Such an integrated system will translate data into actionable information and provide situational awareness.
Children undergoing a variety of neurosurgical procedures present a unique set of challenges to the anesthesiologist caring for these patients. Anesthesiologists must have a clear understanding of not only basic human neurophysiology but also normal and abnormal human motor and cognitive development. Children are not simply small adults, as evidenced by differences in pharmacokinetics, pharmacodynamics, physiologic responses to varying normal and pathologic situations, and demonstration of allometric scaling. Application of these principles informs good clinical care of children for surgical treatment of neurologic disease. This chapter will highlight these aspects of essential clinical care. Further, aspects of pediatric care including discussions of current thinking on cerebral autoregulation, anesthetic induced neurodegeneration, and common clinical situation in pediatric neuroanesthesia will be highlighted.
This historical vignette revisits the main contributions by Nils Lundberg, a neurosurgeon, that were published in the late 1950s and early 1960s. The Lundberg studies also definitively established that symptoms of abnormal brainstem function resulted from abnormal intracranial pressure (ICP), and moreover, even variations in ICP could produce clinical symptoms. The most innovative result of continuous monitoring was the discovery of plateau-shaped waves that produced paradoxical symptoms previously designated as “decerebrate” and “tonic fits” or “acute coning.”
1.
Es wird versucht, durch Messung der Gehirndurchblutung und durch Untersuchungen zur Hmodynamik ein Bild der Vorgnge im Gehirnkreislauf bei pltzlicher Steigerung des LD zu gewinnen.
2.
Eine Steigerung des LD ber die Hhe des intrakraniellen Venendruckes fhrt zu einer Drosselung im vensen System, die intermittierend gesprengt wird. Die Sprengung des Verschlusses ist die Folge des selbstverstndlichen Druckanstieges im vorgeschalteten Kreislaufgebiet, der frequente Wechsel von Verschlu und ffnung der Vene ist dadurch bedingt, da nach Sprengung des Verschlusses der Druck der strmenden Flssigkeit immer niedriger ist als der den Verschlu sprengende Stauungsdruck, so da eine erneute Kompression der Venen eintreten kann.
3.
Die Gehirndurchblutung zeigt infolge dieser Drosselung eine Abnahme: Eine Durchblutungsbeeinflussung beginnt, sobald der LD die normale Hhe des intrakraniellen Venendruckes erreicht bzw. berschritten hat. Fr die Gre der Durchstrmungsverminderung ist magebend die Differenz zwischen mittlerem arteriellem Druck und LD.
4.
Es lt sich nachweisen, da der intrakranielle Venendruck bei LD-Erhhung ansteigt, und zwar von einer bestimmten niedrigen Schwelle an im gleichen Mae wie der LD. Gleichzeitig steigt der Druck im Circulus arteriosus Willisii, whrend der Druck im Sinus sagittalis fllt.
5.
Es konnte gezeigt werden, da sich mit einer Erhhung des Venendruckes der Widerstand im vorgeschalteten Gefgebiet nicht mebar erniedrigt. Es besteht eine lineare Beziehung zwischen arteriovensem Druckgeflle und Durchblutung.
6.
Bei einer strkeren Minderung der Durchblutung bei LD-Steigerung kommt es zu einer Gefdilatation mit Wiederanstieg der Durchblutung infolge Sauerstoffmangelwirkung, nach Wiedersinken des LD dann zu einer reaktiven Hypermie. Die Gefdilatation lt sich durch CO2-Beatmung verstrken. Durch Versuche bei gleichzeitigem Sauerstoffmangel kann abgeleitet werden, da die Blutdrucksteigerung bei sehr starker LD-Erhhung Folge einer Asphyxie der Zentren ist.
7.
Durch einen Vergleich mit den Bedingungen der Sauerstoffversorgung des Gehirns bei Blutdrucksenkung wird gezeigt, inwieweit bei LD-Steigerung mit einer Sauerstoffmangelwirkung am Gehirn zu rechnen ist. Der LD kann um etwa dieselbe Hhe steigen wie der arterielle Mitteldruck fallen derf, bevor kritiche Sauerstoffmangelsymptome eintreten.
- Pilcher C.
Alterations observed in craniocerebral injuries following the use of dehydrating agents.
- Bragdon
Hypothermia in the treatment of cerebral tumours.
- Lundberg
The treatment of cranio-cerebral injuries with especial reference to the non-operable group.
- Munro
Some observations on postoperative ventricular fluid pressure.
- Lundberg