Severe Traumatic Brain Injury (TBI) and aneurysmal Subarachnoid Hemorrhage (SAH) are severe cerebral emergencies. They are common reasons for extensive morbidity and mortality in young people and adults in the western world. This thesis, based on five clinical studies in patients with severe TBI (I-IV) and SAH (V), is concentrated on examination of pathophysiological developments and of evaluation of therapeutic approaches in order to improve outcome after cerebral emergency. The treatment for severe TBI patients at Umeå University Hospital, Sweden is an intracranial pressure (ICP)-targeted therapy according to “the Lund-concept”. This therapy is based on physiological principles for cerebral volume regulation, in order to preserve a normal cerebral microcirculation and a normal ICP. The main goal is to avoid development of secondary brain injuries, thus avoiding brain oedema and worsened microcirculation. Study I is evaluating retrospectively 41 children with severe TBI, from 1993 to 2002. The boundaries of the ICP-targeted protocol were obtained in 90%. Survival rate was 93%, and favourable outcome (Glasgow Outcome Scale, score 4+5) was 80%. Study II is retrospectively analysing fluid administration and fluid balance in 93 adult patients with severe TBI, from 1998 to 2001.The ICP-targeted therapy used, have defined fluid strategies. The total fluid balance was positive day one to three, and negative day four to ten. Colloids constituted 40-60% of total fluids given/day. Severe organ failure was evident for respiratory insufficiency and observed in 29%. Mortality within 28 days was 11%. Study III is a prospective, randomised, double-blind, placebo-controlled clinical trial in 48 patients with severe TBI. In order to improve microcirculation and prevent oedema formation, prostacyclin treatment was added to the ICP-targeted therapy. Prostacyclin is endogenously produced, by the vascular endothelium, and has the ability to decrease capillary permeability and vasodilate cerebral capillaries. Prostacyclin is an inhibitor of leukocyte adhesion and platelet aggregation. There was no significant difference between prostacyclin or placebo groups in clinical outcome or in cerebral microdialysis markers such as lactatepyruvate ratio and brain glucose levels. Study IV is part of the third trial and focus on the systemic release of pro-inflammatory mediators that are rapidly activated by trauma. The systemically released pro-inflammatory mediators, interleukin-6 and CRP were significantly decreased in the prostacyclin group versus the placebo group. Study V is a prospective pilot study which analyses asymmetric dimethylarginine (ADMA) concentrations in serum from SAH patients. Acute SAH patients have cerebral vascular, systemic circulatory and inflammatory complications. ADMA is a marker in vascular diseases which is correlated to endothelial dysfunction. ADMA concentrations in serum were significantly elevated seven days after the SAH compared to admission and were still elevated at the three months follow-up. Our results show overall low mortality and high favourable outcome compared to international reports on outcome in severe TBI patients. Prostacyclin administration does not improve cerebral metabolism or outcome but significantly decreases the levels of pro-inflammatory mediators. SAH seems to induce long-lasting elevations of ADMA in serum, which indicates persistent endothelial dysfunction. Endothelial dysfunction may influence outcome after severe cerebral emergencies.

The volume defined by the rigid cranium is shared by the brain, blood and cerebrospinal fluid (CSF). With every heartbeat the arterial blood volume briefly increases and venous blood and CSF are forced out of the cranium, leading to pulsatility in CSF flow and intracranial pressure (ICP). Altered CSF pulsatility has been linked to idiopathic normal pressure hydrocephalus (INPH), which involves enlarged cerebral ventricles and symptoms of gait/balance disturbance, cognitive decline and urinary incontinence that may be improved by implantation of a shunt. The overall aim of this thesis was to investigate the fluid dynamics of the CSF system, with a focus on pulsatility, and how they relate to INPH pathophysiology and treatment. Mathematical modelling was applied to data from infusion tests, where the ICP response to CSF volume manipulation is measured, to analyse the relationship between mean ICP and ICP pulse amplitude (AMP) before and after shunt surgery in INPH (paper I-II). The observed relationship, designated the pulsatility curve, was found to be constant at low ICP and linear at high ICP, corresponding to a shift from constant to ICP dependent compliance (paper I). Shunt surgery did not affect the pulsatility curve, but shifted baseline ICP and AMP along the curve towards lower values. Patients who improved in gait after surgery had significantly larger AMP reduction than those who did not, while ICP reduction was similar, suggesting that improving patients had baseline ICP in the linear zone of the curve before surgery. Use of this phenomenon for outcome prediction was promising (paper II). The fluid dynamics of an empirically derived pulsatility-based predictive infusion test for INPH was also investigated, with results showing strong influence from compliance (paper III). Clinical ICP data at different body postures was used to evaluate three models describing postural effects on ICP. ICP decreased in upright positions, whereas AMP increased. The model describing the postural effects based on hydrostatic changes in the venous system, including effects of collapse of the jugular veins in the upright position, accurately predicted the measured ICP (paper IV). Cerebral blood flow and CSF flow in the aqueduct and at the cervical level was measured with phase contrast magnetic resonance imaging, and compared between healthy elderly and INPH (paper V). Cerebral blood flow and CSF flow at the cervical level were similar in INPH patients and healthy elderly, whereas aqueductal CSF flow differed significantly. The pulsatility in the aqueduct flow was increased, and there was more variation in the net flow in INPH, but the mean net flow was normal, i.e. directed from the ventricles to the subarachnoid space (paper V). In conclusion, this thesis introduced the concept of pulsatility curve analysis, and provided evidence that pulsatility and compliance are important aspects for successful shunt treatment and outcome prediction in INPH. It was further confirmed that enhanced pulsatility of aqueduct CSF flow was the most distinct effect of INPH pathophysiology on cerebral blood flow and CSF flow. A new model describing postural and hydrostatic effects on ICP was presented, and the feasibility and potential importance of measuring ICP in the upright position in INPH was demonstrated. / <p>Forskningsfinansiär: </p><p>European Union, ERDF: Objective 2, Northern Sweden (grant no. 158715-CMTF). </p>

Idiopathic Normal Pressure Hydrocephalus (INPH) is a condition affecting gait, cognition and continence. Radiological examination reveals enlarged ventricles of the brain. A shunt that drains CSF from the ventricles to the abdomen often improves the symptoms. Much research on INPH has been focused on identifying tests that predict the outcome after shunt surgery. As part of this quest, there are attempts to find measurement methods of intracranial parameters that are valid, reliable, tolerable and safe for patients. Today's technologies for intracranial pressure (ICP) measurement are invasive, often requiring a burr-hole in the skull. Recently, a method for non-invasive ICP measurements was suggested: the Pulsatile Index (PI) calculated from transcranial Doppler data assessed from the middle cerebral artery. In this thesis the relation between PI and ICP was explored in INPH patients during controlled ICP regulation by lumbar infusion. The confidence interval for predicted ICP, based on measured PI was too large for the method to be of clinical utility. In the quest for better predictive tests for shunt success in INPH, recent studies have shown promising results with criteria based on cardiac related ICP wave amplitudes. The brain ventricular system, and the fluid surrounding the spinal cord are in contact. In this thesis it was shown that ICP waves could be measured via lumbar subarachnoid space, with a slight underestimation. One of the cardinal symptoms of hydrocephalus is cognitive impairment. Neuropsychological studies have demonstrated cognitive tests that are impaired and improve after shunt surgery in INPH patients. However, there is currently no standardized test battery and different studies use different tests. In response, in this thesis a fully automated computerized neuropsychological test battery was developed. The validity, reliability, responsiveness to improvement after shunt surgery and feasibility for testing INPH patients was demonstrated. It was also demonstrated that INPH patients were impaired in all subtests, compared to healthy elderly.

Newly created software is presented in magister degree thesis. The software was created for the innovative non–invasive cerebral blood flow autoregulation monitor which has no analogy in the global high tech market. It will be possible at first time to get diagnostic information about the cerebral blood flow autoregulation status of patient with severe brain injuries using such non–invasive monitoring technology in clinical practice. That will help with the individual treatment decision making. Clinical studies were conducted in neurosurgical intensive care units using created software. It has been shown that non–invasive and invasive cerebrovascular blood flow autoregulation monitoring technologies provide the same diagnostic information about the patient status. That conclusion is statistically significant and evidence based. Some R & D projects were performed using non–invasive cerebrovascular blood flow autoregulation monitor with implemented new software. The results of such projects were used in order to formulate the metrological – technological requirements for the final design and development of the innovative non–invasive blood flow autoregulation monitor. Such device is under creation in Telematics Scientific Laboratory which works together with Vittamed Technologijos Ltd and conducts 6.015 million Lt project (BPD04-ERPF-3.1.7-03-05/0020).

Outcome after traumatic brain injury (TBI) depends on the extent of primary cell death and on the development of secondary brain injury. The general aim of this thesis was to find strategies and quality systems to minimize the extent of secondary insults in neurointensive care (NIC). An established standardized management protocol system, multimodality monitoring and computerized data collection, and analysis systems were used. The Uppsala TBI register was established for regular monitoring of NIC quality indexes. For 2008-2010 the proportion of patients improving during NIC was 60-80%, whereas 10% deteriorated. The percentage of ‘talk and die’ cases was &lt; 1%. The occurrences of secondary insults were less than 5% of good monitoring time (GMT) for intracranial pressure (ICP) &gt; 25 mmHg, cerebral perfusion pressure (CPP) &lt; 50 mmHg and systolic blood pressure &lt; 100 mmHg. Favorable outcome was achieved by 64% of adults. Nurse checklists of secondary insult occurrence were introduced. Evaluation of the use of nursing checklists showed that the nurses documented their assessments in 84-85% of the shifts and duration of monitoring time at insult level was significantly longer when secondary insults were reported regarding ICP, CPP and temperature. The use of nurse checklist was found to be feasible and accurate.  A clinical tool to avoid secondary insults related to nursing interventions was developed. Secondary brain insults occurred in about 10% of nursing interventions. There were substantial variations between patients. The risk ratios of developing an ICP insult were 4.7 when baseline ICP ≥ 15 mmHg, 2.9 when ICP amplitude ≥ 6 mmHg and 1.7 when pressure autoregulation ≥ 0.3. Hyperthermia, which is a known frequent secondary insult, was studied. Hyperthermia was most common on Day 7 after admission and 90% of the TBI patients had hyperthermia during the first 10 days at the NIC unit. The effects of hyperthermia on intracranial dynamics (ICP, brain energy metabolism and BtipO2) were small but individual differences were observed. Hyperthermia increased ICP slightly more when temperature increased in the groups with low compliance and impaired pressure autoregulation. Ischemic pattern was never observed in the microdialysis samples. The treatment of hyperthermia may be individualized and guided by multimodality monitoring.

Title: Biomechanical aspects of the dynamics of intracranial pressure in traumatic brain injury Author: Ing. Martin Mayer e-mail: mayercz@seznam.cz Department: Department of Anatomy and Biomechanics Supervisor: doc. PaedDr. Karel Jelen, CSc. This PhD thesis "Biomechanical aspects of the dynamics of intracranial pressure in traumatic brain injury" is about the dynamics of intracranial pressure, particularly in relation to the external mechanical action of the patient. Severe head injury is the leading cause of death in patients under 35 years of age. Despite constantly-improving medical and nursing care only one third of patients, after recovery, regained the ability to live independently in the long term. Two-thirds of patients were severely disabled or died. The lifetime cost of such a patient who was not completely cured has been calculated to be $4,000,000. A significant consequence of craniocerebral injuries are secondary brain lesions, which among other means the rise in intracranial pressure (ICP), which can further exacerbate due to intracerebral or extracerebral causes. Therefore, the objective of the treatment is minimizing secondary injury, optimally at the phase of the primary lesion. However, realization of this requirement, about which we can say that is a conditio sine qua non, sometimes leads...

Made available in DSpace on 2016-06-02T19:48:22Z (GMT). No. of bitstreams: 1 5015.pdf: 5015694 bytes, checksum: 6566e21e5ac67337b4bc48097f1a9ec1 (MD5) Previous issue date: 2013-02-25 / All currently known methods for monitoring intracranial pressure are invasive because a catheter is introduce into the central nervous system causing various damages to the patient especially infection. A new method to monitor intracranial pressure was developed with a minimally invasive surgery, where a sensor is glued to the braincase and captured the bone deformities resulting from increased intracranial pressure. Being a new method is needed to spread the same and training of health professionals regarding the use of the equipment. With the evolution of Communication and Information Technologies became possible learning in real time and from any location through Distance Education. This tool was used in this study in order to disseminate the method for health professionals. The aim of this study was to elaborate the fidelity average prototype of a Virtual Learning Object - OVA about the new method for monitoring intracranial pressure with minimal invasion and evaluate its usability using the heuristics of Nielsen. The fidelity average prototype was developed in the program Microsoft Office PowerPoint ® 2007 following the seven steps of the framework Planning Learning Activities Supported by Computer - PACO. In the evaluation, of ten heuristics proposed by Nielsen eight were violated and found and 388 usability problems. The initial version of the OVA program was developed in the Abobe Flash ® Player 10 by a professional specialist under supervision of the author and according to the suggestions of the reviewers and members of the banking qualification. All screens of the prototype showed some kind of heuristic violated and usability problem countless demonstrating the importance of evaluating the interfaces before exposing the product to the user. The methodology and assessment used in this study were suitable for the proposed objective. / Todos os métodos conhecidos atualmente para monitoração da pressão intracraniana são invasivos, ou seja, é necessário introduzir um cateter no sistema nervoso central acarretando diversos prejuízos ao paciente principalmente risco de infecção. Um novo método para monitorar a pressão intracraniana foi desenvolvido de forma minimamente invasiva, onde um sensor é colado na caixa craniana e captadas as deformações ósseas decorrentes do aumento da pressão intracraniana. Por ser um método novo é necessário a disseminação do mesmo e a capacitação de profissionais da saúde com relação ao uso do equipamento. Com a evolução das Tecnologias da Informação e Comunicação tornou-se possível o aprendizado em tempo real e de qualquer local por meio da Educação a Distância. Esta ferramenta foi utilizada nesse trabalho com vistas a disseminar o método para profissionais de saúde. O objetivo desse estudo foi elaborar o protótipo de média fidelidade de um Objeto Virtual de Aprendizagem - OVA sobre o novo método para monitoração da pressão intracraniana de forma minimamente invasiva e avaliar sua usabilidade utilizando as Heurísticas de Nielsen. O protótipo de média fidelidade foi desenvolvido no programa da Microsoft Office Power Point 2007 ® seguindo as sete etapas do framework Planejamento de Atividades de Aprendizagem Apoiadas por Computador PACO. Na avaliação, das dez heurísticas propostas por Nielsen oito foram violadas e encontrado 388 problemas de usabilidade. A versão inicial do OVA foi desenvolvido no programa da Abobe Flash Player 10® por um profissional especialista sob supervisão da autora e conforme as sugestões dos avaliadores e dos membros da banca de qualificação. Todas as telas do protótipo apresentaram algum tipo de heurística violada e inúmeros problemas de usabilidade demonstrando a importância de avaliar as interfaces antes de expor o produto para o usuário. A metodologia e a avaliação utilizada nesse estudo foram adequadas para o objetivo proposto.

A monitoração intraventricular da pressão intracraniana (PIC) com drenagem contínua do líquido cefalorraquiano (LCR) já é um procedimento difundido na prática da neurocirurgia e considerado de grande importância diagnóstica, terapêutica e prognóstica por sua precisão. Entretanto, por se tratar de um método invasivo, apresenta riscos potenciais de complicações, sendo a infecção a mais freqüente. O presente estudo teve como objetivo verificar e analisar as taxas de infecções decorrentes deste método de monitoração da PIC, assim como as taxas de seus fatores de risco. As informações obtidas através de prontuários e arquivo dos exames laboratoriais foram registradas em duas fichas de coleta de dados próprias e posteriormente submetidas a testes estatísticos como o de Kruskal-Wallis, de Mann-Whitney, de qui-quadrado, teste exato de Fisher e o coeficiente de correlação de Spearman. Obtidas as freqüências relativas e absolutas, médias e desvio-padrão, sendo de 5% o nível de significância utilizado para os testes. A população deste estudo foi de 79 pacientes dos quais 70.9% eram do sexo masculino com média de 33.7 anos, sendo que os diagnósticos presentes em 82.3% eram referentes ao trauma craniencefálico (TCE) seguido de tumores intracranianos e acidentes vasculares cerebrais (AVCs). Todos fizeram uso de antibioticoprofilaxia. A taxa de ventriculite foi de 26.6%, permanecendo o cateter, em média, 6.7 dias e apresentando taxas diárias desta infecção variáveis. Não encontramos associação estatisticamente significativa entre tempo de monitoramento e infecção, porém houve um aumento no índice diário de ventriculite após os três primeiros dias e picos no 6°, 9° e 12° dia indicando uma provável ligação não acumulativa ou linear. Outras variáveis avaliadas neste estudo que apresentaram associação direta com a ocorrência de ventriculite foram o sexo masculino, hemorragia subdural e infecções em outros sítios, principalmente a sepses. Variáveis como idade, procedimentos invasivos, TCE aberto, fístulas liquóricas, hemorragia intraventricular, múltiplas ventriculostomias, presença de PIC acima de 20mmHg, intercorrências durante a cateterização ou manutenção desta não apresentaram associação com a taxa ventriculite, no entanto muitas destas variáveis estiveram presentes em poucos casos dificultando uma conclusão definitiva. / Intraventricular monitoring of the intracranial pressure (ICP) with continuous drainage of cerebrospinal fluid (CSF) is already a widespread procedure in neurosurgical practice and considered as of great diagnostic, therapeutic and prognostic importance due to its precision. However, as it is an invasive method, it presents a potential risk of complications, the infection being the most frequent. The present study aims at verifying and analyzing the rates of infection originating from this monitoring method of ICP, as well as the rates of its risk factors. The information obtained from case histories and laboratory test files were recorded on two own separate data collection cards and later submitted to statistical tests like the Kruskal-Wallis, Mann-Whitney, Chi-Square, Fisher’s exact test, and Spearman correlation coefficients. Relative and absolute, average and standard deviation frequency were verified, 5% was the significance level utilized for the tests. The population of this study was of 79 patients, 70.9% of which were male averaging 37.7 years of age, this being so that the diagnostics present in 82.3% are related to traumatic head injury followed by intracranial tumors and stroke. All of them made use of antibioticprophylaxis. The ventriculitis rate was of 26.6 %, the catheter remaining, on average, 6.7 days and showing variable daily rates of this infection. We have not found a statistically meaningful association between monitoring time and infection, however there was an increase in the daily ventriculitis rate after the first three days and peaks on the 6th, 9th and 12th days showing a probable non-cumulative or linear link. Other variables evaluated in this study which presented a direct association with the occurrence of ventriculitis were the male sex, subdural hemorrhage and infections at other sites, mainly sepsis. Variables such as age, invasive procedures, open traumatic head injury, CSF leaks, intraventricular hemorrhage, multiple ventriculostomies, presence of ICP above 20mmHg, intercurrences during catheterization or its maintenance did not show association with the ventriculitis rate, nevertheless many of these variables were present in few cases making a definite conclusion difficult.

Introdução: O aumento da pressão intracraniana (PIC) é um problema comum na prática neurocirúrgica, e a monitoração invasiva deste parâmetro faz parte da rotina de unidades de terapia intensiva. O Doppler transcraniano vem sendo testado na avaliação da hemodinâmica cerebral como parâmetro de avaliação não invasiva da PIC, porém há controvérsias na literatura sobre seu real benefício e utilidade nesta situação. Este estudo objetivou correlacionar os dados de avaliação do fluxo sanguíneo cerebral através da técnica de Doppler com as variações da monitoração invasiva da PIC na fase aguda de hipertensão intracraniana em um modelo animal. Métodos: Trata-se de um estudo experimental realizado em suínos. O experimento constou de dois grupos de animais (A e B) com hipertensão intracraniana gerada por insuflação com soro fisiológico de um balão no parênquima cerebral, sendo o grupo A com 4 mL e o grupo B com 7 mL. Nos dois grupos houve uma intervenção clínica com infusão de solução salina a 3% e uma simulação de intervenção cirúrgica (desinsuflação do balão). Em todos os momentos de insuflação do balão e das intervenções foram registrados os valores dos monitores de PIC e do Doppler: velocidades sistólica (VS), diastólica (VD), média (VM) do fluxo sanguíneo cerebral e índice de pulsatilidade (IP). Foram realizadas comparações do comportamento dos parâmetros avaliados pela ultrassonografia Doppler craniana (VS, VD, VM e IP) em relação às variações da PIC intraparenquimatosa. Resultados: Foram estudados 20 suínos sendo 10 no grupo A e 10 no grupo B. Um animal do grupo B foi excluído do estudo, pois foi a óbito antes do término do experimento. Após a insuflação do balão, como era de se esperar, a PIC no grupo B foi superior à do grupo A em todos os momentos, até a desinsuflação do mesmo. Realizada a correlação de Spearman observou-se correlação significativa entre IP e PIC, principalmente logo após insuflação do balão, ou seja, na elevação abrupta da PIC. Não houve correlação entre a PIC e os parâmetros VS, VD e VM. Também não houve variação significativa da PIC após infusão endovenosa de solução salina hipertônica. Conclusão: Este resultado demonstra o potencial do IP como bom parâmetro de avaliação de pacientes com suspeita de elevação hiperaguda e recente da PIC. Não se conseguiu demonstrar os mesmos resultados de correlação entre a PIC e as demais variáveis VS, VD e VM. Diante destes achados, adicionados aos dados conflitantes da literatura disponível até o momento, não se recomenda, por enquanto, a utilização desses parâmetros isoladamente como substitutos da monitoração invasiva da PIC, evidenciando a necessidade de mais estudos clínicos e experimentais / Introduction: Increased intracranial pressure (ICP) is a common problem in neurosurgical practice. Invasive monitoring of ICP in these cases is part of the intensive care unit routine. Transcranial Doppler has been tested in the evaluation of cerebral hemodynamics as a non-invasive evaluation of ICP, but there are controversies in the literature about its real benefit and usefulness in this situation. Thus, this study aimed to correlate the data of cerebral blood flow assessment using the Doppler technique and the invasive monitoring of ICP in the acute phase of intracranial hypertension in an animal model. Methods: This is an experimental study in pigs. During the experiment, an intracerebral expansive mass with an inflatable balloon was simulated. The experiment consisted of two groups (A and B) of animals with intracranial hypertension generated by a ballon inflation inside the cerebral parenchima, group A with 4 mL and group B with 7 mL. In both groups there was a clinical intervention with infusion of 3% saline solution and a simulation of surgical intervention (balloon drain out). The values of ICP and Doppler parameters (systolic (FVs), diastolic (FVd), and mean (FVm) cerebral blood flow velocities) were collected at all moments of balloon inflation and interventions, as well as the pulsatility index (PI). Comparisons of the behavior of the parameters evaluated by Doppler ultrasound (FVs, FVd, FVm and PI) were performed in relation to intraparenchymal ICP. Results: Twenty pigs were studied, 10 in group A and 10 in group B. One pig died in group B and it was excluded. After balloon inflation, as expected, ICP in group B was higher than in group A at all times, until the ballon was empty again. Significant correlation between PI and ICP was obtained when Spearman correlation was performed, mainly shortly after balloon inflation, that is, in the abrupt elevation of ICP. There was no correlation between ICP and FVs, FVd or FVm. There was also no significant change in ICP after intravenous infusion of hypertonic saline solution. Conclusion: These results demonstrate the potential of PI as a good parameter for the evaluation of patients with suspected ICP elevation. It was not possible to demonstrate the same correlation results between the ICP and FVs, FVd or FVm. Due to these results and also to the literature conflicting data to date, the use of these parameters alone as substitutes for the invasive monitoring of ICP is not recommended until now, which shows the need for further clinical and experimental studies

Les dernières années ont laissé place à de nombreuses avancées médicales, montrant de plus en plus d’intérêt à l’amélioration des modalités de soin et du cadre de vie des patients, en apportant plus d’efficacité et moins de risque. Dans ce contexte, trois études de recherche clinique ont été menées avec le potentiel microphonique cochléaire (PMC) pour évaluer les capacités de cette réponse cochléaire dans des applications médicales originales et proposer des outils de surveillance de grand intérêt pour la prise en charge des patients. La première étude s’est intéressée à la survenue de surdités suite aux exérèses de neurinome de l’acoustique, notamment les pertes auditives d’origine vasculaire. L’amplitude du PMC a détecté tous les événements chirurgicaux responsables de l’altération de la vascularisation cochléaire et a ainsi fourni une meilleure compréhension de l’origine des pertes auditives lors des chirurgies dans l’angle pontocérébelleux. Les deux autres études ont porté sur la fiabilité d’un monitorage non invasif de la pression intracrânienne (PIC) par la phase du PMC sur une longue période de suivi, chez des patients pour lesquels il est attendu une variation de la PIC. Le PMC a montré une bonne capacité à détecter les variations de la PIC au cours du temps, aussi bien lors d’une installation lente d’une PIC élevée (progression de gliome malin) que lors de l’apparition transitoire et aiguë d’une PIC augmentée (hypertension intracrânienne, hydrocéphalie).Plusieurs observations parfois inattendues ont été obtenues avec le PMC et ouvrent de nouvelles pistes d’intérêt et de réflexion sur les mécanismes de fonctionnement de la PIC ou de la cochlée. Parmi elles : une répercussion épisodique de l’embolisation des anévrysmes cérébraux sur la PIC, l’aptitude de la phase du PMC à prédire la survenue prochaine d’une crise de Menière et la possible prédiction préopératoire d’une fragilité cochléaire au fraisage du conduit auditif interne quand le signal IRM des fluides cochléaires du côté affecté (par le neurinome de l’acoustique) est hypointense. / The last years, healthcare and living conditions of patients have been of growing interest in medical advances with the goal to bring more efficiency and less risk. In this context, three clinical researches have been conducted with cochlear microphonic potential (CMP) to assess the abilities of this cochlear response in unusual medical applications and propose monitoring tools of major interests for patients’ management.The first study is interested in the occurrence of deafness following vestibular schwannoma resection, in particular hearing loss due to vascular origin. The CMP amplitude detected all the surgical events responsible for the alteration of the cochlear vascularization and thus provided a better understanding of the origin of the hearing losses during surgeries in the cerebellopontine angle.The other two studies examined the reliability of non-invasive intracranial pressure (ICP) monitoring, by the CMP phase, over a long period to follow patients for whom a change in ICP is expected. The CMP has shown good ability to detect changes in ICP over time, both in a slow installation of a high ICP (progression of malignant glioma) and in the transient and acute onset of increased ICP (intracranial hypertension, hydrocephalus).Several observations, sometimes unexpected, have been obtained with the CMP and open up new track of interest and reflections on the mechanisms of ICP and cochlea functioning. These discoveries included: episodic repercussion of cerebral aneurysm embolization on ICP, ability of CMP phase to predict the next occurrence of a Meniere crisis, and preoperative prediction of cochlear fragility during the drilling of the internal auditory meatus when the MRI signal of the cochlear fluids on the affected side (vestibular schwannoma) is hypointense.