The management of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

Aneurysmal subarachnoid hemorrhage (SAH) is a rare event affecting relatively young patients therefore leading to a high social impact. The management of SAH follows a biphasic course with early brain injuries in the first 72 hours followed by a phase at risk of secondary deterioration due to delayed cerebral ischemia (DCI) in 20 to 30% patients. Cerebral infarction from DCI is the most preventable cause of mortality and morbidity after SAH. DCI prevention, early detection and treatment is therefore advocated. Formerly limited to the occurrence of vasospasm, DCI is now associated with multiple pathophysiological processes involving for instance the macrocirculation, the microcirculation, neurovascular units, and inflammation. Therefore, the therapeutic targets and management strategies are also evolving and are not only focused on proximal vasospasm. In this review, we describe the current knowledge of DCI pathophysiology. We then discuss the diagnosis strategies that may guide physicians at the bedside with a multimodal approach in the unconscious patient. We will present the prevention strategies that have proven efficient as well as future targets and present the therapeutic approach that is currently being developed when a DCI occurs.

Intraoperative cerebral blood flow monitoring in neurosurgery: A review of contemporary technologies and emerging perspectives.

Intraoperative monitoring of cerebral blood flow (CBF) has become an invaluable adjunct to vascular and oncological neurosurgery, reducing the risk of postoperative morbidity and mortality. Several technologies have been developed during the last two decades, including laser-based techniques, videomicroscopy, intraoperative MRI, indocyanine green angiography, and thermography. Although these technologies have been thoroughly studied and clinically applied outside the operative room, current practice lacks an optimal technology that perfectly fits the workflow within the neurosurgical operative room. The different available technologies have specific strengths but suffer several drawbacks, mainly including limited spatial and/or temporal resolution. An optimal CBF monitoring technology should meet particular criteria for intraoperative use: excellent spatial and temporal resolution, integration in the operative workflow, real-time quantitative monitoring, ease of use, and non-contact technique. We here review the main contemporary technologies for intraoperative CBF monitoring and their current and potential future applications in neurosurgery.

Diagnostic accuracy of quantitative EEG to detect delayed cerebral ischemia after subarachnoid hemorrhage: A preliminary study.

OBJECTIVE: Delayed cerebral ischemia (DCI) is the most important and preventable morbidity cause after subarachnoid hemorrhage (SAH). Therefore, DCI early detection is a major challenge. Yet, neurological examination can be unreliable in poor grade SAH patients. EEG provides information from most superficial cortical area, with ischemia-related changes. This study aims at defining an alpha-theta/delta (AT/D) ratio decrease thresholds to detect DCI. METHODS: We used EEG with a montage matching vascular territories (right and left anterior central and posterior) and compared them to follow-up brain imaging. RESULTS: 15 SAH patients (Fischer ≥ 3, World Federation of Neurological Surgeons scale ≥4, 9 DCI) were monitored during 6.4 [4-8] days (min = 2d, max = 13d). AT/D changes could follow three different patterns: (1) prolonged or (2) transient decrease and (3) no decrease or progressive increase. A regional 30% decrease outlasting 3.7 h reached 100% sensitivity and 88.9% specificity to detect DCI. Only 22.6% were in a zone of uncertain diagnosis (3.7-8.04 h). These prolonged decreases, with a loss of transient changes, started in cortical areas evolving toward DCI, and preceded intracranial changes when available. CONCLUSION: Although this study has a small sample size, prolonged AT/D decrease seems to be a reliable biomarker of DCI. SIGNIFICANCE: cEEG changes are likely to precede cerebral infarction and could be useful at the bedside to detect DCI before irreversible damage.

Use of a hand-held digital cognitive aid in simulated crises: the MAX randomized controlled trial.

BACKGROUND: Cognitive aids improve the technical performance of individuals and teams dealing with high-stakes crises. Hand-held electronic cognitive aids have rarely been investigated. A randomized controlled trial was conducted to investigate the effects of a smartphone application, named MAX (for Medical Assistance eXpert), on the technical and non-technical performance of anaesthesia residents dealing with simulated crises. METHODS: This single-centre randomized, controlled, unblinded trial was conducted in the simulation centre at Lyon, France. Participants were anaesthesia residents with >1 yr of clinical experience. Each participant had to deal with two different simulated crises with and without the help of a digital cognitive aid. The primary outcome was technical performance, evaluated as adherence to guidelines. Two independent observers remotely assessed performance on video recordings. RESULTS: Fifty-two residents were included between July 2015 and February 2016. Six participants were excluded for technical issues; 46 participants were confronted with a total of 92 high-fidelity simulation scenarios (46 with MAX and 46 without). Mean (sd) age was 27 (1.8) yr and clinical experience 3.2 (1.0) yr. Inter-rater agreement was 0.89 (95% confidence interval 0.85-0.92). Mean technical scores were higher when residents used MAX [82 (11.9) vs 59 (10.8)%; P<0.001]. CONCLUSION: The use of a hand-held cognitive aid was associated with better technical performance of residents dealing with simulated crises. These findings could help digital cognitive aids to find their way into daily medical practice and improve the quality of health care when dealing with high-stakes crises. CLINICAL TRIAL REGISTRATION: NCT02678819.