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Perioperative critical care management for patients with aneurysmal subarachnoid hemorrhage
Kiwon Lee,H. Alex Choi,Nancy Edwards,Tiffany Chang,Robert N. Sladen 대한마취통증의학회 2014 Korean Journal of Anesthesiology Vol.67 No.2
Despite significant regional and risk factor-related variations, the overall mortality rate in patients suffering from aneurysmal subarachnoid hemorrhage (SAH) remains high. Compared to ischemic stroke, which is typically irreversible, hemorrhagic stroke tends to carry a higher mortality, but patients who do survive have less disability. Technologies to monitor and treat complications of SAH have advanced considerably in recent years, but good long-term functional outcome still depends on prompt diagnosis, early aggressive management, and avoidance of premature withdrawal of support. Endovascular procedures and open craniotomy to secure a ruptured aneurysm represent some of the numerous critical steps required to achieve the best possible result. In this review, we have attempted to provide a contemporary, evidence-based outline of the perioperative critical care management of patients with SAH. This is a challenging and potentially fatal disease with a wide spectrum of severity and complications and an often protracted course. The dynamic nature of this illness, especially in its most severe forms, requires considerable flexibility in clinician management, especially given the panoply of available treatment modalities. Judicious hemodynamic monitoring and adaptive therapy are essential to respond to the fluctuating nature of cerebral vasospasm and the varying oxygen demands of the injured brain that may readily induce acute or delayed cerebral ischemia.
Critical Care for Patients with Massive Ischemic Stroke
전상범,고윤석,H. Alex Choi,이기원 대한뇌졸중학회 2014 Journal of stroke Vol.16 No.3
Malignant cerebral edema following ischemic stroke is life threatening, as it can cause inadequate blood flow and perfusion leading to irreversible tissue hypoxia and metabolic crisis. Increased intracranial pressure and brain shift can cause herniation syndrome and finally brain death. Multiple randomized clinical trials have shown that preemptive decompressive hemicraniectomy effectively reduces mortality and morbidity in patients with malignant middle cerebral artery infarction. Another life-saving decompressive surgery is suboccipital craniectomy for patients with brainstem compression by edematous cerebellar infarction. In addition to decompressive surgery, cerebrospinal fluid drainage by ventriculostomy should be considered for patients with acute hydrocephalus following stroke. Medical treatment begins with sedation, analgesia, and general measures including ventilatory support, head elevation, maintaining a neutral neck position, and avoiding conditions associated with intracranial hypertension. Optimization of cerebral perfusion pressure and reduction of intracranial pressure should always be pursued simultaneously. Osmotherapy with mannitol is the standard treatment for intracranial hypertension, but hypertonic saline is also an effective alternative. Therapeutic hypothermia may also be considered for treatment of brain edema and intracranial hypertension, but its neuroprotective effects have not been demonstrated in stroke. Barbiturate coma therapy has been used to reduce metabolic demand, but has become less popular because of its systemic adverse effects. Furthermore, general medical care is critical because of the complex interactions between the brain and other organ systems. Some challenging aspects of critical care, including ventilator support, sedation and analgesia, and performing neurological examinations in the setting of a minimal stimulation protocol, are addressed in this review.
The Monitoring of Brain Edema and Intracranial Hypertension
Mohammad I Hirzallah,H. Alex Choi 대한신경집중치료학회 2016 대한신경집중치료학회지 Vol.9 No.2
Preventing secondary brain injury after neurological insults is one of the primary goals of the neurocritical care unit. Our understanding of the roles of intracranial pressure (ICP) and cerebral edema in managing patients in the neurocritical care units is still evolving. Recent clinical trials examining the monitoring and treatment of elevated ICP have influenced the way we think about intracranial hypertension. Additionally, new methods of monitoring ICP, new physiologic surrogates derived from ICP measurements, and evolving technology to measure cerebral edema are currently being studied and tested for clinical efficacy. In this article, we will discuss both traditional and novel methods of monitoring ICP and cerebral edema.
Demonstration of Traumatic Subarachnoid Hemorrhage from the Anterior Choroidal Artery
Sim, Ki-Bum,Park, Sukh Que,Choi, H. Alex,Kim, Daniel H. The Korean Neurosurgical Society 2014 Journal of Korean neurosurgical society Vol.56 No.6
We present a case of angiographically confirmed transection of the cisternal segment of the anterior choroidal artery (AChA) associated with a severe head trauma in a 15-year old boy. The initial brain computed tomography scan revealed a diffuse subarachnoid hemorrhage (SAH) and pneumocephalus with multiple skull fractures. Subsequent cerebral angiography clearly demonstrated a complete transection of the AChA at its origin with a massive extravasation of contrast medium as a jet trajectory creating a plume. We speculate that severe blunt traumatic force stretched and tore the left AChA between the internal carotid artery and the optic tract. In a simulation of the patient's brain using a fresh-frozen male cadaver, the AChA is shown to be vulnerable to stretching injury as the ipsilateral optic tract is retracted. We conclude that the arterial injury like an AChA rupture should be considered in the differential diagnosis of severe traumatic SAH.
황순욱(S. W. Hwang),최경호(G. H. Choi),박용헌(Sam. Park),R. Michael Ench,Alex M. Bate,이상철(S. C. Lee),권오성(O. S. Kwon),이동하(D. H. Lee) 한국태양에너지학회 2012 한국태양에너지학회 학술대회논문집 Vol.2012 No.3
Proton Exchange Membrane Fuel Cells (PEMFC) are the most appropriate for energy source of small robot applications. PEMFC has superior in power density and thermodynamic efficiency as compared with the Direct Methaol Fuel Cell (DMFC). Furthermore, PEMFC has lighter weight and smaller size than DMFC which are very important factors as small robot power system. The most significant factor of mobile robots is weight which relates closely with energy consumption and robot operation. This research tried to find optimum specifications in terms of type, number of cell, active area, cooling method, weight, and size. In order to find optimum 500W PEMFC, six options are designed in this paper and studied to reduce total stack weight by applying new materials and design innovations. However, still remaining problems are thermal management, robot space for energy sources, and so on. For a thermal management, design options need to analysis of Computational Fluid Dynamics (CFD) for determining which option has the improved performance and durability.
황순욱,최경호,박용헌,이상철,권오성,이동하,Hwang, S.W.,Choi, G.H.,Park, Sam.,Ench, R. Michael,Bates, Alex M.,Lee, S.C.,Kwon, O.S.,Lee, D.H. 한국태양에너지학회 2012 한국태양에너지학회 논문집 Vol.32 No.suppl3
Proton Exchange Membrane Fuel Cells (PEMFC) are the most appropriate for energy source of small robot applications. PEMFC has superior in power density and thermodynamic efficiency as compared with the Direct Methaol Fuel Cell (DMFC). Furthermore, PEMFC has lighter weight and smaller size than DMFC which are very important factors as small robot power system. The most significant factor of mobile robots is weight which relates closely with energy consumption and robot operation. This research tried to find optimum specifications in terms of type, number of cell, active area, cooling method, weight, and size. In order to find optimum 500W PEMFC, six options are designed in this paper and studied to reduce total stack weight by applying new materials and design innovations. However, still remaining problems are thermal management, robot space for energy sources, and soon. For a thermal management, design options need to analysis of Computational Fluid Dynamics (CFD) for determining which option has the improved performance and durability.
전상범,권순억,박중철,이덕희,윤성철,Yeon-Jung Kim,안재성,Byung Duk Kwun,강동화,H. Alex Choi,Kiwon Lee,김종성 대한뇌졸중학회 2016 Journal of stroke Vol.18 No.3
Background and Purpose Hemicraniectomy is a decompressive surgery used to remove a large bone flap to allow edematous brain tissue to bulge extracranially. However, early indicators of the decompressive effects of hemicraniectomy are unclear. We investigated whether reduction of midline shift following hemicraniectomy is associated with improved consciousness and survival in patients with malignant middle cerebral artery infarctions. Methods We studied 70 patients with malignant middle cerebral artery infarctions (MMI) who underwent hemicraniectomies. Midline shift was measured preoperatively and postoperatively using computed tomography (CT). Consciousness level was evaluated using the Glasgow Coma Scale on postoperative day 1. Patient survival was assessed six months after stroke onset. Results The median time interval between preoperative and postoperative CT was 8.3 hours (interquartile range, 6.1–10.2 hours). Reduction in midline shift was associated with higher postoperative Glasgow Coma Scale scores (P<0.05). Forty-three patients (61.4%) were alive at six months after the stroke. Patients with reductions in midline shifts following hemicraniectomy were more likely to be alive at six months post-stroke than those without (P<0.001). Reduction of midline shift was associated with lower mortality at six months after stroke, after adjusting for age, sex, National Institutes of Health Stroke Scale score, and preoperative midline shift (adjusted hazard ratio, 0.71; 95% confidence interval, 0.62–0.81; P<0.001). Conclusions Reduction in midline shift following hemicraniectomy was associated with improved consciousness and six-month survival in patients with MMI. Hence, it may be an early indicator of effective decompression following hemicraniectomy.
Kim, Tae Jung,Ko, Sang-Bae,Jeong, Han-Gil,Kim, Chi Kyung,Kim, Yerim,Nam, Kiwoong,Mo, Heejung,An, Sang Joon,Choi, H. Alex,Yoon, Byung-Woo American Academy of Sleep Medicine 2017 Journal of clinical sleep medicine Vol.13 No.11
<P>Conclusions: NOD in the SU was associated with END, especially during nighttime, after ischemic stroke. This suggests that treatment of sleep-disordered breathing could be a modifiable factor to possibly reduce the risk of neurological worsening among acute stroke patients.</P>