EEG en réanimation : quelles indications,quel matériel ?

There is a growing development of continuous EEG monitoring (cEEG) in the intensive care unit (ICU) management of neurological patients. Its main objective is the detection of epileptic seizures or status epilepticus because the sensitivity of standard short-duration EEG recording in the ICU is poor. The aim of monitoring is to allow rapid recognition and treatment of epileptic complications in order to decrease secondary insults to the brain and improve outcome. Several studies have demonstrated that a large proportion of patients has epileptic crisis after subarachnoid haemorrhage, stroke or brain trauma, without any clinical manifestation. The EEG feature has also demonstrated a prognosis value but its value for clinical management needs further studies. Another application of EEG in the ICU is monitoring depth of anaesthesia or barbiturate treatment. Due to artifacts contamination, this is possible only in deeply sedated of paralyzed patients. The impact or cEEG monitoring on clinical management and its indications have to be further defined.     

Rôle délétère de l’hyperthermie en neuroréanimation

Fever is a secondary brain injury and may worsen neurological prognosis of neurological intensive care unit (NICU) patients. In response to an immunological threat, fever associates various physiological reactions, including hyperthermia. Its definition may vary but the most commonly used threshold is 37.5 °C. In animal studies, hyperthermia applied before, during or after cerebral ischemia may increase the volume of ischemic lesions. The mechanism of this effect may include increase in blood brain barrier permeability, increase in excitatory amino acid release and increase in free radical production. In NICU patients, fever is frequent, occurring in up to 20–30% of patients. Moreover, after haemorrhagic stroke, fever has been reported in 40–50% of patients. In half of the patients, fever may be related to an infectious cause but in more than 25% of patients, hyperthermia may be of central origin. After ischemic stroke, hyperthermia during the first 72 hours is associated with an increase in infarct size and increase in morbidity and mortality. This holds true also after subarachnoid haemorrhage. After traumatic brain injury, fever is not related to mortality but may increase morbidity. Whereas no causal link has been established between fever and unfavourable outcome, it seems reasonable to treat hyperthermia in patients suffering from brain injuries. In such patients, antipyretics have a moderate efficacy. In case of failure, they should be replaced by physical cooling techniques.     

Agressions cérébrales,immunité et infections

Infections are a major cause of death and morbidity after acute injury of the central nervous system (CNS). Acute lesions of the CNS alter immune homeostasis contributing to the development of immunosuppression (IS), and making the bed of the infection. IS results in a decreased phagocytic functions of neutrophils and macrophages as well as monocyte deactivation (decreased capacity of antigen presentation to lymphocytes). The immune abnormalities occur very quickly and may last for weeks. The neurovegetative system is closely connected to the secondary lymphoid organs where cells of innate immunity receive information from injured organs inducing the long lasting adaptive immune response (immune synapse). The sympathetic system is critically involved in the IS through production of anti-inflammatory mediators like interleukin-10. This may prove important as all types of acute injury of the CNS can lead to direct damage to sympathetic centers. Specialized units of care for ischemic stroke, taking into account the risk of infection related to the IS, have improved the prognosis until 18th month after the initial damage of the SNC. It is now well recognized that the improved long-term prognosis is related with the secondary prevention of recurrent ischaemia as well as aggressive management of pulmonary infections. A better understanding of the pathophysiology of IS can be considered in the near future, opening the door to immunomodulatory therapeutic trials.     

Stratégie de réhabilitation postopératoire de la fracture du col fémoral

The femoral neck fracture in elderly patient is an entity that is within the scope of “disease causing a femoral neck fracture”. The specific factors for successful management of these elderly patients are centered around patient's comorbidities, specific management in a clinical pathway, and more or less early rehabilitation after surgery. The type of fracture, surgery, specific treatment, early active recovery for the patients lying in bed after surgery optimize the functional outcome at mean term. The improvement of nutritional status, equilibrium for comorbidities and early rehabilitation with walking activities and physiotherapy significantly improve functional outcome at short and medium terms and postoperative mortality. The use of multimodal analgesia and regional analgesia primarily by perioperative continuous femoral nerve blocks also improve the medical prognosis and functional outcome of the patient.     

Intérêt du monitorage de l’index bispectral (BIS) pour la détection précoce des hypoperfusions cérébrales

Objectives

The goal of the study was to assess whether clinically significant cerebral hypoperfusion in awake patients would be associated with some alterations in the values of the bispectral index (BIS) monitoring.

Study design

Observational study.

Population and methods

We monitored the BIS during endovascular carotid artery occlusion testing in awake patients.

Results

Twenty-eight patients were included. Twenty-one adequately tolerated the procedure. Their BIS value remained stable throughout the procedure. Four patients had poor angiographic tolerance, but no clinical symptoms. Their BIS value slightly decreased during the test (minimal BIS: 83 [79–87]). Three patients had poor clinical and angiographic tolerance of the occlusion. They all experienced an immediate and dramatic decrease in their BIS value (minimal BIS: ipsilateral to clamping: 50 [45–60]; contralateral to clamping: 48 [45–52]). In all patients, the clinical symptoms and the BIS normalized after deflating the occlusion balloon.

Conclusion

In awake patients, the observed values of the BIS monitoring seem to be associated with clinically relevant cerebral hypoperfusion.     

Pas de chirurgie sans échographie préalable en cas de thrombose veineuse superficielle clinique : à propos d’un cas d’embolie paradoxale grave

Lower limbs superficial venous thrombosis (LLSVT) is usually considered as common and of a benign prognosis. LLSVT can, however, be responsible for major thromboembolic complications: lower limbs deep vein thrombosis (LLDVT) and pulmonary embolism (PE). We report a case of a LLSVT complicated with a massive bilateral PE and an ischemic cerebral stroke, occurring immediately after a varicose vein surgery. Venous ultrasonography of the lower limbs must be systematically performed in case of LLSVT, in order to evaluate the presence of an associated LLDVT. A rigorous diagnostic and therapeutic approach is the only way to optimize the treatment of this disorder, and to avoid the occurrence of dramatic venous thromboembolic complications.     

Impact de la mise en place d’un réseau de soins en traumatologie sur la mortalité des patients traumatisés graves du bassin

Aim

To evaluate the impact of a regional trauma network on intra-hospital mortality rates of patients admitted with severe pelvic trauma.

Study

Retrospective observational study.

Patients

Sixty-five trauma patients with serious pelvic fracture (pelvic abbreviated injury scale [AIS] score of 3 or more).

Methods

Demographic, physiologic and biological parameters were recorded. Observed mortality rates were compared to predicted mortality according to the Trauma Revised Injury Severity Score methodology adjusted by a case mix variation model.

Results

Twenty-nine patients were admitted in a level I trauma centre (reference centre) and 36 in level II trauma centres (centres with interventional radiology facility and/or neurosurgery). Patients from the level I trauma centre were more severely injured than those who were admitted at the level II trauma centres (Injury Severity Score [ISS]: 30 [13–75] vs 22 [9–59]; P < 0.01). Time from trauma to hospital admission was also longer in level I trauma centre (115 [50–290] min vs 90 [28–240] min, P < 0.01). Observed mortality rates (14%; 95% confidence interval, 95% CI, [1–26%]) were lower than the predicted mortality (29%; 95% CI [13–44%]) in the level I trauma centre. No difference in mortality rates was found in the level II trauma centres.

Conclusion

The regional trauma network could screen the most severely injured patients with pelvic trauma to admit them at a level I trauma centre. The observed mortality of these patients was lower than the predicted mortality despite increased time from trauma to admission.     

Les dangers de l’hypothermie thérapeutique

Therapeutic hypothermia (less than 35 °C) is a promising strategy to improve neuroprotection after severe brain injury. Except in patients resuscitated from cardiac arrest, its effectiveness has not yet been demonstrated. Therapeutic hypothermia results in various side effects, including cardiovascular, hydroelectrolytic and infectious disorders, which could explain, in part, the lack of conclusive clinical studies. These hazards are associated with practical difficulties to induce and maintain targeted hypothermia and with rewarming management. An improvement in the techniques for achieving targeted hypothermia, more knowledge about side effects and further randomized clinical trials are needed before recommending the use of therapeutic hypothermia for patients with severe traumatic brain injury.     

Hypothermie et protection cérébrale après traumatisme crânien. Influence des gaz du sang

The usefulness of therapeutic hypothermia is highly debated after traumatic brain injury. A neuroprotective effect has been demonstrated only in experimental studies: decrease in cerebral metabolism, restoration of ATP level, better control of cerebral edema and cellular effects. Despite negative multicenter clinical studies, therapeutic hypothermia is still used to a better control of intracranial pressure. However, important issues need to be clarified, particularly the level and duration of hypothermia, the depth and modalities of sedation. A clear understanding of blood gases variations induced by hypothermia is needed to understand the cerebral perfusion and oxygenation changes. It is essential to recognize and to use hypothermia-induced physiological hypocapnia and alkalosis under strict control of cerebral oxygen balance (jugular venous saturation or tissue PO₂) and also to take into account the increased affinity of hemoglobin for oxygen. Management of post-traumatic intracranial hypertension using hypothermia, directed by intracranial pressure level, and consequently for long duration, is potentially beneficial but needs further clarification.     

Chirurgie arthroscopique de l’épaule et complications ischémiques cérébrales

The authors report three cases in which cerebral ischemia occurred during arthroscopic shoulder surgery performed in beach chair position under general anaesthesia and interscalene plexus block. Several similar cases have been published in the literature. This rare but extremely severe complication is related to the decrease in cerebral perfusion pressure (CPP). Monitoring of CPP in the beach chair position using the measurement of arterial pressure and taking into account the hydrostatic gradient is essential. Prevention includes correction of preoperative hypovolaemia, treatment of postural arterial hypotension, adequate installation of the patient's head, aggressive treatment of perioperative arterial hypotension (whatever the cause) and avoidance of deliberate perioperative arterial hypotension. Routine use of non-invasive monitoring of cerebral oxygenation has been advocated to avoid this accident but its usefulness has to be confirmed by clinical studies.     

Rupture traumatique trachéobronchique : gestion des voies aériennes

We report the case of a 25-year-old man who suffered a severe trauma with a complete rupture and separation of the right main bronchus. The patient presented on the scene with respiratory distress and severe hypoxemia. At the admission in the trauma resuscitation unit, the CT scan and fiberoptic examination confirmed the diagnosis of right main bronchus rupture. Selective fiberoptic intubation of the left main bronchus was done and the patient was sent to the operating theater for urgent thoracotomy. During thoracotomy, profound arterial oxygen desaturation requested the right main bronchus being intubated by the surgeon under the control of view and separate lung ventilation, until the end of the bronchus suture. Surgery allowed the patient to survive. He was then discharged alive from the hospital at day 36. Severe tracheobronchial rupture may be rapidly associated with major respiratory distress and severe hypoxemia that necessitate specialised care in referring centre. Initial orientation of these patients appears to be as important that airway and hypoxemia management.     

L’oxymétrie cérébrale transcutanée en anesthésie pédiatrique

Cerebral oximetry allows continuous real-time and non-invasive monitoring of cerebral oxygen saturation (cSO₂), by measuring oxyhaemoglobin and deoxyhaemoglobin near infrared light absorption, similarly to pulse oximetry. cSO₂ measurement predominantly reflects brain venous compartment, and is correlated with jugular venous saturation. As jugular venous saturation, cSO₂ must therefore be interpreted as a measure of balance between transport and consumption of O₂ in the brain. Cerebral oximetry should be used as a trend monitoring, because its accuracy is insufficient to be considered as reliable measure of absolute value of ScO₂. In adult, correction of intraoperative cerebral desaturation reduces hospital stay, heavy morbidity and mortality, and serious postoperative neurocognitive impairment after cardiac and major abdominal surgery. In children, the occurrence of intra- and postoperative cerebral desaturations during congenital heart surgery is associated with increased neurological morbi-mortality. Cerebral oximetry could be a useful monitoring during anaesthesia of (ex) preterm neonates, due to the risk of impaired cerebral blood flow autoregulation in these patients.     

Hyperoxie normobarique chez le patient traumatisé crânien

Cerebral ischaemia plays a major role in the outcome of brain-injured patients. Because brain oxygenation can be assessed at bedside using intra-parenchymal devices, there has been a growing interest about whether therapeutic hyperoxia could be beneficial for severely head-injured patients. Normobaric hyperoxia increases brain oxygenation and may improve glucose-lactate metabolism in brain regions at risk for ischaemia. However, benefits of normobaric hyperoxia on neurological outcome are not established yet, that hinders the systematic use of therapeutic hyperoxia in head-injured patients. This therapeutic option might be proposed when brain ischemia persists despite the optimization of cerebral blood flow and arterial oxygen blood content.     

Œdème cérébral : nouvelles pistes thérapeutiques

Cerebral oedema (CO) after brain injury can occur from different ways. The vasogenic and cytotoxic oedema are usually described but osmotic and hydrostatic CO, respectively secondary to plasmatic hypotonia or increase in blood pressure, can also be encountered. Addition of these several mechanisms can worsen injuries. Consequences are major, leading quickly to death secondary to intracerebral hypertension and later to neuropsychic sequelae. So therapeutic care to control this phenomenon is essential and osmotherapy is actually the only way. A better understanding of physiopathological disorders, particularly energetic ways (lactate), aquaporine function, inflammation lead to new therapeutic hopes. The promising experimental results need now to be confirmed by clinical data.     

Phénotypage métabolique par résonance magnétique nucléaire pour l’évaluation périopératoire et en réanimation

Metabolic phenotyping consists in the identification of subtle and coordinated metabolic variations associated with various pathophysiological stimuli. Different analytical methods, such as nuclear magnetic resonance, allow the simultaneous quantification of a large number of metabolites. Statistical analyses of these spectra thus lead to the discrimination between samples and the identification of a metabolic phenotype corresponding to the effect under study. This approach allows the extraction of candidate biomarkers and the recovery of perturbed metabolic networks, driving to the generation of biochemical hypotheses (pathophysiological mechanisms, diagnostic tests, therapeutic targets…). Metabolic phenotyping could be useful in anaesthesiology and intensive care medicine for the evaluation, monitoring or diagnosis of life-threatening situations, to optimise patient managements. This review introduces the physical and statistical fundamentals of NMR-based metabolic phenotyping, describes the work already achieved by this approach in anaesthesiology and intensive care medicine. Finally, potential areas of interest are discussed for the perioperative and intensive management of patients, from newborns to adults.     

Chirurgie éveillée des gliomes cérébraux : plaidoyer pour un investissement accru des anesthésistes

The recent development of awake surgery in neuro-oncology allowed a conceptual change, i.e. the realization of resection for invasive brain tumors according to functional and not anatomic boundaries. This paradigmatic shift enabled a significant improvement of results in surgery for gliomas, by opening the door to resections within eloquent areas classically considered as “inoperable”, while preserving and even improving the quality of life of patients. In addition, the extent of resections has been maximized, leading to an increase of median survival – especially in low-grade gliomas. Strong relationships between the different teams (surgeons, neuropsychologists, anaesthesiologists) are crucial for the development and improvement of awake surgery. Thus, it seems important that anesthesiologists can benefit from a clear and accurate knowledge of the real contribution of this procedure, in order to better evaluate the balance between the theoretical risks of surgery under local anesthesia versus the actual risk of not performing resection with a maximum of safety and efficiency for the patients. The purpose of this plea is to advocate the spread of awake surgery in routine practice, due to its major impact on both functional and survival outcomes, by nonetheless keeping in mind that a multidisciplinary staff is mandatory for selection of patients as well as into the operating room. In this state of mind, anaesthesiologists have to play a central role, through an increased involvement in this field.     

Aspects médicolégaux de la prise en charge de la prééclampsie

When analyzing various recommendations formulated by the colleges of specialty, as well as precedents, the following guidelines can be formulated with respect to communication as part to the management of PE.