Multimodales Monitoring in der Neurointensivmedizin

The prognosis of neurointensive care patients depends largely on the occurrence of secondary ischemic/hypoxic tissue damage, which is mediated by different pathomechanisms, such as edema formation or increased intracranial pressure. Due to the cerebral damage and need for sedation as well as intubation, clinical assessment of these patients is limited. Furthermore, clinical signs of secondary damage, such as advanced herniation syndromes are often delayed and therefore mostly indicate irreversible brain damage. To adequately predict and detect secondary neuronal damage, various neuromonitoring techniques have been developed in recent years with ongoing technical refinement. These can be used for bedside and ideally continuous monitoring of various functional systems of the brain. Neuromonitoring is used to implement early therapeutic measures before irreversible brain damage has occurred, to monitor therapeutic effects, for evaluation of the prognosis and to improve the neurological outcome of patients. Different monitoring techniques are often combined in multimodal neuromonitoring. This article gives an overview of the most promising neuromonitoring techniques available.     

Thermal therapies in interventional MR imaging. Cryotherapy

Cryotherapy of the brain is an old and well-established technique of functional and resective neurosurgery. With the use of modern imaging techniques such as MR imaging, which is ideally suited for diagnosis, planning, and monitoring of an ablation procedure, cryotherapy can become a modern alternative to other ablation techniques. In contrast to hyperthermal ablation tools such as laser or radiofrequency ablation, cryotherapy has specific potentials. First and most importantly, the freezing process ideally can be precisely monitored by MR imaging during the procedure without any specific temperature-sensitive pulse sequence. As shown in the experimental study, several techniques including conventional gradient echo sequences, ultrafast subsecond MR sequences, and MR fluoroscopy, are suited for monitoring the freezing process. Furthermore, the volume of the damaged tissue, as imaged by MR imaging, does not increase after completion of the ablation procedure. The extension of the ice corresponds well to the final, histologically confined necrosis and allows a high predictability of the resulting necrosis. Although not yet in clinical use, the combination of minimally invasive modern cryotherapy devices and ultrafast interventional MR techniques offer a promising alternative to other ablation techniques. In addition, it holds great promise for minimally invasive neurologic procedures in the near future. Further technical modifications and clinical studies, however, are necessary to establish the potential of this new treatment option.     

Continuous monitoring of patients with extensive strokes. Importance of monitoring on the neurological intensive care unit

One of the main functions of neurologic intensive care units (NICU) is to provide continuous monitoring of critically ill patients. Space-occupying stroke is a disease with high mortality. While clinical assessment of these comatose patients is difficult, additional monitoring is of key importance. With this information, intensive care physicians may recognize pathophysiologic changes earlier, thus making the right timing of therapeutic interventions easier. Every patient admitted to the NICU receives a basic monitoring which combines noninvasive and invasive methods. Additionally, some specialized centers are exploring the new method of multimodal monitoring. This allows continuous monitoring of physiologic parameters of brain function and compliance. The following article attempts to explain methods of neurointensive care monitoring and its importance for the treatment of stroke. Furthermore, we describe new developments in patient monitoring.     

Measurement of gastric accommodation: a reappraisal of conventional and emerging modalities

Impaired gastric accommodation is an important cause of functional dyspepsia. Currently available tests that evaluate gastric accommodation provide relevant physiological information, but they pose technical difficulties and their clinical impact remains controversial. Gastric barostat remains the gold standard, but it is an invasive procedure. In recent years, emerging modalities including single photon emission computed tomography (SPECT), three‐dimensional ultrasound and magnetic resonance imaging have been developed to measure gastric volumes and hold promise as alternative methods of assessing gastric accommodation non‐invasively. Studies are underway to validate these techniques with recent data proving the performance characteristics of SPECT. The non‐invasive nutrient drink test measures satiety scores as a surrogate marker of gastric accommodation and remains controversial. More recently, intragastric monitoring has been proposed as yet another non‐invasive modality to assess gastric accommodation. Each of these different modalities brings its associated advantages and disadvantages, as is discussed in this review. Ongoing studies to validate these new techniques are in progress and are likely to lead to further progress in neurogastroenterology.     

"Semi-invasive" vs. invasive approaches for intracranial EEG and seizure monitoring in epilepsy

When non-invasive studies fail to provide sufficient localising data to permit resective epilepsy surgery, intracranial seizure monitoring may have to be performed. Various techniques are available with specific advantages as well as disadvantages. "Semi-invasive" techniques, despite their name, remain essentially "invasive". The choice for a specific approach therefore should depend on the clinical problem in each individual patient rather than on theoretical preference.     

Continuous EEG monitoring in patients with subarachnoid hemorrhage.

Patients with subarachnoid hemorrhage (SAH) are at risk for seizures and delayed cerebral ischemia, both of which can be detected with continuous EEG monitoring (cEEG). Ischemia can be detected with EEG at a reversible stage. CEEG may be most useful in patients with poor grade SAH, as the neurological exam is of limited utility in these stuporous or comatose patients. Seizures have been detected in 19% of SAH patients undergoing cEEG, with the vast majority (95%) of these seizures being nonconvulsive and without any detectable clinical correlate. Applying quantitative analysis to the cEEG (relative alpha variability, post-stimulation alpha/delta ratio) allows reliable detection of ischemia from vasospasm, with EEG changes often preceding changes in the clinical exam and other non-continuous monitoring techniques by up to two days. In patients at risk for developing vasospasm, cEEG monitoring, preferably with quantitative EEG analysis, should be started as early as possible and carried out for up to 14 days after the SAH. CEEG findings may lead to therapeutic (e.g., antiepileptic medication, hypertensive therapy, angioplasty) or additional diagnostic interventions such as angiography, CT or MRI.     

Continuous EEG monitoring in the intensive care unit: an overview.

Due to technological advances, it is now feasible to record continuous digital EEG (CEEG), with or without video, in critically ill patients and review recordings remotely. Nonconvulsive seizures (NCSzs) are more common than previously recognized and are associated with worse outcome. The majority of seizures in ICU patients are nonconvulsive and will be missed without CEEG. Factors associated with an increased risk for NCSzs include coma, prior clinical seizures, CNS infection, brain tumor, recent neurosurgery, and periodic epileptiform discharges. In addition to detecting seizures, CEEG is also useful for characterizing paroxysmal spells such as posturing or autonomic changes, detecting ischemia, assessing level of sedation, following long-term EEG trends, and prognosticating. Most NCSzs will be detected in the first 24 hours of CEEG in noncomatose patients, but longer recording periods may be required in comatose patients or in those with periodic epileptiform discharges. EEG patterns in encephalopathic or comatose patients are often equivocal. How aggressively to treat NCSzs and equivocal EEG patterns in these patients is unclear and requires further research. Real-time detection of ischemia at a reversible stage is technologically feasible with CEEG and should be developed into a practical form for prevention of in-hospital infarction in the near future.     

Continuous EEG-SEP monitoring of severely brain injured patients in NICU: methods and feasibility.

AIMS: To evaluate the feasibility of a continuous neurophysiologic monitoring (electroencephalography (EEG)-somatosensory evoked potentials (SEPs)) in the neuro-intensive care unit (NICU), taking into account both the technical and medical aspects that are specific of this environment. METHODS: We used an extension of the recording software that is routinely used in our unit of clinical neurophysiology. It performs cycles of alternate EEG and SEP recordings. Raw traces and trends are simultaneously displayed. Patient head and stimulator box are placed behind the bed and linked to the ICU monitoring terminal through optic fibers. The NICU staff has been trained to note directly clinical events, main artefacts and therapeutic changes. The hospital local area network (LAN) enables remote monitoring survey. RESULTS: Continuous EEG (CEEG)-SEP monitoring was performed in 44 patients. Problems of needle detachment were seldomly encountered, thanks to the use of a sterile plastic dressing, which covers needles. We never had infection or skin lesions due to needles or the electrical stimulator. The frequent administration of sedative at high doses prevented us from having a clinically valuable EEG in several cases but SEPs were always monitorable, independently of the level of EEG suppression. The diagnosis of seizures and non-epileptic status was based on raw EEG, while quantitative EEG (QEEG) was used to quantify ictal activity as a guide to treatment. CONCLUSIONS: EEG and EP waveforms collected in NICU were of comparable quality to routine clinical measurements and contained the same clinical information. A continuous SEP monitoring in a comatose and sedated patient in NICU is not technically more difficult and potentially less useful than in operating room. This monitoring appears to be feasible provided the observance of some requirement regarding setting, electrodes, montages, personnel integration, consulting and software.     

Data analysis for continuous EEG monitoring in the ICU: seeing the forest and the trees.

Continuous EEG monitoring (CEEG) is a powerful tool for evaluating cerebral function in obtunded and comatose critically ill patients. The ongoing analysis of CEEG data is a major task because of the volume of data generated during monitoring and the need for near real-time interpretation of a patient's EEG patterns. Advances in digital EEG data acquisition, computer processing, data transmission, and data display have made CEEG monitoring in the intensive care unit technically feasible. A variety of quantitative EEG tools such as Fourier analysis and amplitude-integrated EEG, and other methods of data analysis such as computerized seizure detection, increasingly allow for focused review of EEG epochs of potential interest. These tools reduce the tremendous time burdens that accompany analysis of the complete CEEG data stream, and allow bedside personnel and nonexpert staff to potentially recognize significant EEG changes in a timely fashion. This article uses literature review and clinical case examples to illustrate techniques for the display and analysis of intensive care unit CEEG recordings. Areas requiring further research and development are discussed.     

Physiology and clinical relevance of induced hypothermia

Experimental evidence and clinical experience suggest that mild hypothermia protects numerous tissues from damage during ischemic insult. However, the extent to which hypothermia becomes a valued therapeutic option will depend on the clinician’s ability to rapidly reduce core body temperature and safely maintain hypothermia. To date, general anesthesia is the best way to block autonomic defenses during induction of mild-to-moderate hypothermia; unfortunately, general anesthesia is not an option in most patients likely to benefit from therapeutichy pothermia. Induction of hypothermia in a wake humans is complicated by both the technical difficulties related to thermal manipulation and the remarkable efficacy of thermoregulatory defenses, especially vasoconstriction and shivering. The most effective thermal manipulation devices are generally invasive and, therefore, more prone to complications than surface methods. In an effort to inhibit thermoregulation in awake humans, several agents have been tested either alone or in combination with each other. For example, the combination of meperidine and buspirone has already been applied to faciltate induction of hypothermia in human trials. However, pharmacological induction of thermoregulatory tolerance to cold without excessive sedation, respiratory depression, or other serious toxicity remains a major focus of current therapeutic hypothermia research.     

Clinical application of compressed spectral array in long-term EEG monitoring of comatose patients.

To obtain continuous information about the cerebral electrical activity in the early course of coma, an apparatus was designed which included a small fast computer capable of calculating the Fourier transform. The practical application of this system of CSA to 123 comatose patients in a neurosurgical intensive care unit overcame the technical difficulties connected both with the patient's and environmental conditions. The advantages of such a technique are mainly due to its capacity of synthetising EEG signals and to its clarity of presentation, which is easily grasped even by people not specifically trained in electroencephalography. Hours of EEG activity are compressed into a pictorial and synoptic representation that shows in real time the distribution and temporal behaviour of frequencies as well as the intensity of total electrical activity. The immediate detection of these parameters permits evaluation of any worsening or improvement of cerebral electrogenesis, as well as of the inter-hemispheric asymmetries at their onset. EEG monitoring thus provides useful elements for assessing the comatose state in individual cases and for adjusting treatment. Finally, the spectrographic aspect of the first 48 h, as a whole, carries a great prognostic significance. The most striking finding from this study was the confirmation that the comatose states that, in their early course, show only a fixed slow-wave EEG activity are far more rare than those that display an electrical activity changing in time.     

Non-invasive study of airways inflammation in sleep apnea patients

The current view foresees that airway inflammation and oxidative stress are both important in the pathophysiology of obstructive sleep apnea syndrome (OSAS). Notwithstanding the fact that these events play a key role in OSAS, their monitoring is not included in the current management of this disease.The direct sampling of airways is made possible today thanks to what can be defined as quite invasive techniques, such as bronchoscopy with broncho-lavage and biopsy. Recently there has been increasing interest in the non-invasive methods that allow the study of airways via the induced sputum (IS), the exhaled breath volatile mediators and the exhaled breath condensate (EBC). The non-invasiveness of these techniques makes them suitable for the evaluation and serial monitoring of OSAS patients. The aim of this review is to spread current knowledge on the non-invasive airway markers and on their potential clinical applications in OSAS.     

Using video-oculography for galvanic evoked vestibulo-ocular monitoring in comatose patients

Binocular eye movement responses to galvanic vestibular stimulation were measured in comatose patients. Healthy persons have been demonstrated to show a consistent and reproducible relationship between eye movement and galvanic vestibular stimulation. Any pathology of the vestibular integrating structures (brainstem and to some degree the cerebellum and cortex) is assumed to influence this response pathognomonically. A monitoring facility was designed to record eye movements during galvanic labyrinth polarization (GaLa) in order to examine the vestibular response in comatose patients. GaLa was applied by means of two pairs of electrodes attached between the mastoid and interscapular region. A custom-built, battery-driven current-source stimulator served to generate sinusoidal stimuli that could be applied either unilaterally or simultaneously and independently to the left and right labyrinths. The resultant binocular eye movements were recorded using a Chronos Eye Tracker and the digital image sequences stored for subsequent analysis. Repeated testing was performed in five comatose patients with a Glasgow Coma Score of 3, who were intubated and ventilated (subarachnoid hemorrhage (n = 3), traumatic injury (n = 2)). The observed ocular movements varied. In four cases ocular movements in response to GaLa were observed, while one patient showed neither spontaneous nor galvanic-induced eye movements. The latter was diagnosed as brain-dead 2 days after testing. In contrast, the patients who showed ocular movements synchronous with galvanic stimulation left the intensive care unit (ICU) for rehabilitation. These data indicate that it is possible to assess brain function in comatose patients by evaluating the vestibulo-ocular response to galvanic stimulation. The designed monitoring facility can be used on the ICU ward without disconnection of other monitoring equipment.     

Endoscope and neuronavigational assistance in acoustic neurinoma microsurgery

INTRODUCTIONMinimalinvasivetechniqueshavehadanenormousimpactafterbeingintroducedandestab－lishedinmodernneurosurgery．Alsoinacousticneurinomasurgeryestablishingthesekindoftech－niqueshasbecomefromhighimportance犤１～３犦．Longbeforethemicroscopestartsitst     

Alpha coma EEG pattern in patients with severe COVID-19 related encephalopathy

ObjectiveEncephalopathy is a major neurological complication of severe Coronavirus Disease 2019 (COVID-19), but has not been fully defined yet. Further, it remains unclear whether neurological manifestations are primarily due to neurotropism of the virus, or indirect effects, like cerebral hypoxia.MethodsWe analysed the electroencephalograms (EEGs) of 19 consecutive patients with laboratory-confirmed COVID-19, performed at peak disease severity as part of their clinical management. Disease severity, respiratory failure, immune and metabolic dysfunction, sedation status, and neurological examination on the day of the EEG were noted.ResultsSevere encephalopathy was confirmed in 13 patients, all with severe COVID-19; 10 remained comatose off sedation, and five of them had alpha coma (AC). Disease severity, sedation, immune and metabolic dysfunction were not different between those with AC and those without.ConclusionsSevere COVID-19 encephalopathy is a principal cause of persisting coma after sedation withdrawal. The relatively high incidence of the rare AC pattern may reflect direct SARS-CoV-2 neurotropism with a predilection for the brainstem ascending reticular system.SignificanceSystematic early EEG detection of encephalopathy related to severe COVID-19 is important for the acute care and the management of long-term neurological and cognitive sequelae, and may help our better understanding of its pathophysiology.     

Continuous EEG monitoring in the neuroscience intensive care unit and emergency department.

This article reviews established, emergent, and potential applications of continuous EEG (CEEG) monitoring in the Neuroscience Intensive Care Unit (NICU) and Emergency Department. In each application, its goal as a neurophysiologic monitor is to extend our powers of observation to detect abnormalities at a reversible stage and to guide timely and physiologically sound interventions. Since this subject was reviewed 5 years ago, the use of CEEG monitoring has become more widespread. In a modern NICU, it is no longer novel to have CEEG data contributing to management decisions. A well-trained CEEG monitoring team is important for its optimal implementation. In the diagnosis and management of convulsive and nonconvulsive status epilepticus, its value appears established. It is finding benefit in the early diagnosis and management of precarious cerebral ischemia, including severe acute cerebral infarctions and post-SAH vasospasms. In comatose patients, it can provide diagnostic and prognostic information which is otherwise unobtainable. More recently, it has been found advantageous for targeting management of acute severe head trauma patients. Networking technology has facilitated the implementation and oversight of CEEG monitoring and promises to expand its availability, credibility, and effectiveness. The maturing of CEEG use is reflected in preliminary efforts to assess its cost benefit, cost effectiveness, and impact on patient outcomes.     

Paradigm changes in spine surgery-evolution of minimally invasive techniques

Minimally invasive spine surgery (MISS) techniques were developed to address morbidities associated with open spinal surgery approaches. MISS was initially applied for indications such as the microendoscopic decompression of stenosis (MEDS)-an operation that has become widely implemented in modern spine surgery practice. Minimally invasive surgery for MEDS is an excellent example of how an MISS technique has improved outcomes compared with the use of traditional open surgical procedures. In parallel with reports of surgeon experience, accumulating clinical evidence suggests that MISS is favoured over open surgery, and one could argue that the role of MISS techniques will continue to expand. As the field of minimally invasive surgery has developed, MISS has been implemented for the treatment of increasingly difficult and complex pathologies, including trauma, spinal malignancies and spinal deformity in adults. In this Review, we present the accumulating evidence in support of minimally invasive techniques for established MISS indications, such as lumbar stenosis, and discuss the need for additional level I and level II data to demonstrate the benefit of MISS over traditional open surgery. The expanding utility of MISS techniques to address an increasingly broad range of spinal pathologies is also highlighted.     

Relationships between cardiac pain and objective markers of transient myocardial ischemia

Cardiac pain is a key symptom for diagnosis of myocardial ischemia in man, even if a minority of transient myocardial ischemic episodes are painful. A multiparametric monitoring approach - associating non-invasive and invasive monitoring techniques during transient myocardial ischemia with and without pain - allows to achieve a clinical diagnosis and obtain information about the pathophysiology of the anginal syndrome.     

The evolution of neuroimaging of spinal cord injury patients over the last decade.

A review is presented concerning the development of new neuroimaging techniques in the last decade which have improved the diagnostic exploration of patients with spinal cord injuries, including studies of possible sequelae. A number of technical developments occurred in the 1980s, which have broadened the diagnostic capabilities of neuroimaging and made its investigative techniques more precise and less invasive. In a summarized way the new or upgraded modalities such as magnetic resonance imaging and angiography, computed tomography and ultrasound, are considered here with regard to the effect that they have had on the clinical management of patients with a traumatized spinal cord.     

Upper airway resistance syndrome

This article reviews the clinical picture, diagnosis and management of the upper airway resistance syndrome (UARS). Presently, there is not enough data on key points like the frequency of UARS and the morbidity associated with this condition. Furthermore, the existence of LIARS as an independent sleep disorder and its relation with snoring and obstructive events is in debate. The diagnosis of UARS is still a controversial issue. The technical limitations of the classic approach to monitor airflow with thermistors and inductance plethysmography, as well as the lack of a precise definition of hypopnea, may have led to a misinterpretation of UARS as an independent diagnosis from the sleep apnea/hypopnea syndrome. The diagnosis of this syndrome can be missed using a conventional polysomnographic setting unless appropriate techniques are applied. The use of an esophageal balloon to monitor inspiratory effort is currently the gold standard. However, other sensitive methods such as the use of a pneumotachograph and, more recently, nasal cannula/pressure transducer systems or on-line monitoring of respiratory impedance with the forced oscillation technique may provide other interesting possibilities. Recognition and characterization of this subgroup of patients within sleep breathing disorders is important because they are symptomatic and may benefit from treatment. Management options to treat UARS comprise all those currently available for sleep apnea/hypopnea syndrome (SAHS). However, the subset of patients classically identified as LIARS that exhibit skeletal craneo-facial abnormalities might possibly obtain further benefit from maxillofacial surgery.