Bedside ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure in nontraumatic neurocritically ill patients

BACKGROUND Delay in treatment of raised intracranial pressure(ICP)leads to poor clinical outcomes.Optic nerve sheath diameter(ONSD)by ultrasonography(US-ONSD)has shown good accuracy in traumatic brain injury and neurosurgical patients to diagnose raised ICP.However,there is a dearth of data in neuro-medical intensive care unit(ICU)where the spectrum of disease is different.AIM To validate the diagnostic accuracy of ONSD in non-traumatic neuro-critically ill patients.METHODS We prospectively enrolled 114 patients who had clinically suspected raised ICP due to non-traumatic causes admitted in neuro-medical ICU.US-ONSD was performed according to ALARA principles.A cut-off more than 5.7 mm was taken as significantly raised.Raised ONSD was corelated with raised ICP on radiological imaging.Clinical history,general and systemic examination findings,SOFA and APACHE 2 score and patient outcomes were recorded.RESULTS There was significant association between raised ONSD and raised ICP on imaging(P<0.001).The sensitivity,specificity,positive and negative predictive value at this cut-off was 77.55%,89.06%,84.44% and 83.82% respectively.The positive and negative likelihood ratio was 7.09 and 0.25.The area under the receiver operating characteristic curves was 0.844.Using Youden’s index the best cut off value for ONSD was 5.75 mm.Raised ONSD was associated with lower age(P=0.007),poorer Glasgow Coma Scale(P=0.009)and greater need for surgical intervention(P=0.006)whereas no statistically significant association was found between raised ONSD and SOFA score,APACHE II score or ICU mortality.Our limitations were that it was a single centre study and we did not perform serial measurements or ONSD pre-and post-treatment or procedures for raised ICP.CONCLUSION ONSD can be used as a screening a test to detect raised ICP in a medical ICU and as a trigger to initiate further management of raised ICP.ONSD can be beneficial in ruling out a diagnosis in a low-prevalence population and rule in a diagnosis in a high-prevalence population.

Epidural Blood Patches Performed with Miethke Sensor Reservoir for Continuous Intracranial Pressure Monitoring

An epidural blood patch (EBP) is a procedure performed by injecting autologous blood into a patient’s epidural space, usually at the site of a suspected CSF leak. It is typically performed in patients with characteristic postural headaches due to low intracranial pressure. We report a case of a young female with an implanted Miethke Sensor Reservoir, which was used for continuous intracranial pressure (ICP) monitoring during a two-level epidural blood patch. ICP increased only with thoracic injection, suggesting thoracic EBP may have greater efficacy than lumbar EBP in treating SIH and PDPH when the site of CSF leak is unknown.

《A management algorithm for patients with intracranial pressure monitoring:the Seattle International Severe Traumatic Brain Injury Consensus Conference(SIBICC)》解读

2019年国际专家团基于Delphi方法的反复调查和现场讨论,完成了"A management algorithm for patients with intracranial pressure monitoring:the Seattle International Severe Traumatic Brain Injury Consensus Conference(SIBICC)"(简称"共识"),旨在引导对仅行颅内压监测的颅脑创伤患者实施合理的分级管理。本文对"共识"所涉及的"三阶梯颅内压管理流程"、各级治疗措施的应用原则,以及镇静治疗和颅内压监测停撤的判断流程进行解读,以期将国际颅脑创伤神经重症研究进展介绍给读者。

Intracranial pressure monitoring:Gold standard and recent innovations

Intracranial pressure monitoring (ICP) is based on the doctrine proposed by Monroe and Kellie centuries ago. With the advancement of technology and science, various invasive and non-invasive modalities of monitoring ICP continue to be developed. An ideal monitor to track ICP should be easy to use, accurate, reliable, reproducible, inexpensive and should not be associated with infection or haemorrhagic complications. Although the transducers connected to the extra ventricular drainage continue to be Gold Standard, its association with the likelihood of infection and haemorrhage have led to the search for alternate noninvasive methods of monitoring ICP. While Camino transducers, Strain gauge micro transducer based ICP monitoring devices and the Spiegelberg ICP monitor are the emerging technology in invasive ICP monitoring, optic nerve sheath diameter measurement, venous opthalmodynamometry, tympanic membrane displacement, tissue resonance analysis, tonometry, acoustoelasticity, distortionproduct oto-acoustic emissions, trans cranial doppler, electro encephalogram, near infra-red spectroscopy, pupillometry, anterior fontanelle pressure monitoring, skull elasticity, jugular bulb monitoring, visual evoked response and radiological based assessment of ICP are the non-invasive methods which are assessed against the gold standard.

Prognostic value of intracranial pressure monitoring for the management of hypertensive intracerebral hemorrhage following minimally invasive surgery

BACKGROUND:The incidence of hypertensive intracerebral hemorrhage(HICH)has been increasing during the recent years in low-and middle-income countries.With high mortality and morbidity rates,it brings huge burden to the families.It lacks evidence regarding the application of intracranial pressure(ICP)monitoring in HICH.In the current study,the authors aimed to evaluate whether ICP monitoring could make any difference on the prognosis of HICH patients after minimally invasive surgery.METHODS:A retrospective review of 116 HICH patients admitted to the Second Affiliated Hospital of Zhejiang University School of Medicine,between 2014 and 2016,was performed.The effects of ICP monitoring on 6-month mortality and favorable outcomes were evaluated by univariate and logistic regression analysis.RESULTS:ICP monitors were inserted into 50 patients.Patients with ICP monitoring had a significantly better outcome(P<0.05).The average in-hospital duration in patients with ICP monitoring was shorter than that in the patients without ICP monitoring(16.68 days vs.20.47 days,P<0.05).Mortality rates between ICP monitoring and no ICP monitoring did not differ significantly(16.0%vs.15.1%,P=0.901).On univariate analysis,age,Glasgow Coma Scale(GCS)on admission and presence of ICP monitor were independent predictors of 6-month favorable outcomes.CONCLUSION:ICP monitoring is associated with a better 6-month functional outcome compared with no ICP monitoring.Future study is still needed to confirm our results and elucidate which subgroup of HICH patients will benefit most from the minimally invasive surgical intervention and ICP monitoring.

Amendment on the strain measurement of thin-walled human skull shell as intracranial pressure changes

The human skull, composed of tabula extema, tabula intema, and a porous diploe sandwiched in between, is deformed with changing intracranial pressure （ICP）. Because the human skull＇s thickness is only 6 mm, it is simplified as a thin-walled shell. The objective of this article is to analyze the strain of the thin-wailed shell by the stress-strain calculation of a human skull with changing ICP. Under the same loading conditions, using finite element analysis （FEA）, the strains of the human skull were calculated and the results were compared with the measurements of the simulative experiment in vitro. It is demonstrated that the strain of the thin-walled shell is totally measured by pasting the one-way strain foils on the exterior surface of the shell with suitable amendment for data. The amendment scope of the measured strain values of the thin-walled shell is from 13.04% to 22.22%.

Changes of Nitric Oxide and Its Relationship with Clinical Features,Intracranial Pressure and Outcome in Acute Head Injury

To investigate the content and dynamics of nitric oxide (NO) in the cerebrospinal fluid (CSF) of patients with acute head injury and to clarify the relationship of NO with clinical features and intracranial pressure (ICP) as well as outcomes, 38 adults with acute head injury were studied. Glasgow Coma Scale (GCS) obtained at admission and Glasgow Outcome Scale (GOS) 3 months after injury was assessed. ICP was surveyed via intraventricular catheter and lumbar puncture and CSF samples were obtained simultaneously. NO was determined with Griess reagents. Results showed that NO peak content in the head injury group was significantly higher than that of the control group. During dynamic research, no peak content of mildly injured cases and severely injured ones appeared in different time windows respectively. The peak value of NO was distinctly higher in the severe group than in the mild group. NO peak value of the raised ICP group was remarkably higher than that of the normal ICP group. The peak value of NO was considerately higher in the poor outcome group than in the good outcome group. When the content of NO was over 6. 5 μmol/L, the rate of poor outcome was increased. There existed a correlation between NO and GCS, ICP and GOS. It is concluded that the content of NO was increased in patients with acute head injury and the changes of NO had different time windows in severely injured patients and mildly injured ones. The more sever the injury, the higher the NO content; and the more serious the secondary brain injury and brain edema, the worse the outcomes. When NO is combined with GCS, GOS and ICP, it increases the accuracy of judgement to the degree of head injury and outcome.

Outcomes of high-grade aneurysmal subarachnoid hemorrhage patients treated with coiling and ventricular intracranial pressure monitoring

BACKGROUND High-grade aneurysmal subarachnoid hemorrhage is a devastating disease with a low favorable outcome.Elevated intracranial pressure is a substantial feature of high-grade aneurysmal subarachnoid hemorrhage that can result to secondary brain injury.Early control of intracranial pressure including decompressive craniectomy and external ventricular drainage had been reported to be associated with improved outcomes.But in recent years,little is known whether external ventricular drainage and intracranial pressure monitoring after coiling could improve outcomes in high-grade aneurysmal subarachnoid hemorrhage.AIM To investigate the outcomes of high-grade aneurysmal subarachnoid hemorrhage patients with coiling and ventricular intracranial pressure monitoring.METHODS A retrospective analysis of a consecutive series of high-grade patients treated between Jan 2016 and Jun 2017 was performed.In our center,followed by continuous intracranial pressure monitoring,the use of ventricular pressure probe for endovascular coiling and invasive intracranial pressure monitoring in the acute phase is considered to be the first choice for the treatment of high-grade patients.We retrospectively analyzed patient characteristics,radiological features,intracranial pressure monitoring parameters,complications,mortality and outcome.RESULTS A total of 36 patients were included,and 32(88.89%)survived.The overall mortality rate was 11.11%.No patient suffered from aneurysm re-rupture.The intracranial pressure in 33 patients(91.67%)was maintained within the normal range by ventricular drainage during the treatment.A favorable outcome was achieved in 18 patients(50%)with 6 mo follow-up.Delayed cerebral ischemia and Glasgow coma scale were considered as significant predictors of outcome(2.066 and-0.296,respectively,P<0.05).CONCLUSION Ventricular intracranial pressure monitoring may effectively maintain the intracranial pressure within the normal range.Despite the small number of cases in the current work,high-grade patients may benefit from a combination therapy of early coiling and subsequent ventricular intracranial pressure monitoring.

Closed cranial window rodent model for investigating hemodynamic response to elevated intracranial pressure

Background:Elevated intracranial pressure(ICP)occurs in several physiological and pathological conditions,yet long-term sequellae are not common,which implies that blood flow is preserved above ischemic thresholds.Methods:This pilot study sought to confirm this hypothesis using a closed cranial window model in a rat in which ICP was elevated to 120 mmHg for 12 min,and superficial cortical perfusion was measured by laser Doppler flowmetry and laser speckle flowmetry.Results:Following a transient increase,cortical blood flow decreased to between 25%and 75%of baseline.These levels correspond to disrupted metabolism and decreased protein synthesis but did not exceed thresholds for electrical signaling or membrane integrity.This may partially explain how some episodes of elevated ICP remain benign.Conclusion:The closed cranial window model provides a platform for prospective study of physiologic responses to artificially elevated ICP during neurosurgery to promote hemostasis.

Increased intracranial pressure and macular thickening:is there a link?

Dear Editor,I am Dr. Hamid Sajjadi, director of Neuro-Ophthalmology at San Jose Eye and Laser Medical Center in California USA and director of Department of Ophthalmology, Acacia Medical Center, Dubai, UAE. I write to present three cases of macular thickening (MT) and micro-papilledema associated with increased intracranial pressure (IICP).

Intracranial Pressure and the Role of the Vagus Nerve: A Hypothesis

There is reason to believe that the vagus nerve carries sensory afferent messages from the intracranial cavity as it does from the other body cavities. Considering the arachnoid granulations as a secretory apparatus instead of an organ transporting cerebrospinal fluid, a simple model can be built. Assuming that the arachnoid granulations produce nitric oxide in accordance with changes in the intracranial pressure, the jugular foramen with the vagus nerve lying just subendothelially is where this message would be received. Other chemical substances from the granulations or other intracranial tissues could of course also act as messengers. This would mean that the brain stem could adjust to changes in intracranial pressure with small changes in cerebral venous resistance. The general idea is that intracranial pressure is a passive function of the intracranial pressure-volume relationship. But the hypothesis suggests that the vagus nerve constantly mediates changes in intracranial pressure to the brain stem that can rapidly adjust cerebral venous resistance. This control is totally intracranial and easily overridden by considerable changes in absorption of spinal fluid or intracranial calamities. This article looks for clues in support of the idea that the vagus nerve mediates intracranial pressure changes to the brain stem.

Research Progresses in Effects of Analgesics and Sedatives on Intracranial Pressure of Neurointensive Care Patients

At present, there are some concerns and problems to treat neurointensive care patients by using analgesics and sedatives. Conditions of neurointensive care patients change quickly. For neurointensive care patients who cannot have auxiliary examination timely, clinicians judge intracranial conditions mainly through relevant monitoring devices and consciousness and pupil changes of patients. The use of analgesics and sedatives is limited due to worry about influences on consciousness evaluation and judgment and different degrees of inhibition on cardiovascular system and respiratory system. Common sedatives (e.g. benzodiazepines) and common analgesics (e.g. morphine, fentanyl and sufentanil) both may inhibit respiration. The specification often provides taboos for the use of drugs by patients with increase intracranial pressure (ICP) and craniocerebral injuries. Through literature review, the author analyzed influences of analgesics and sedatives on ICP of neurointensive care patients comprehensively.

Correlation study of relative parameters of intracranial pressure and prognosis of patient with craniocerebral injury

Objective:To analyze the correlation of the relative parameters of intracranial pressure to the prognosis in patients with craniocerebral injury.Methods:The clinical data of 80 patients with closed craniocerebral injury were retrospectively analyzed,and all of these patients underwent conventional examinations of arterial blood pressure and intracranial pressure.Neumatic DCR system was used to monitor relative parameters of intracranial pressure from patients.According to the score of Glasgow outcome scale(GOS)upon discharge,they were divided into favorable prognosis group(GOSⅢ-Ⅴ,n=46)and unfavorable prognosis group(GOSⅠ-Ⅱ,n=34).The relative parameters of intracranial pressure of two groups were compared so as to analyze the correlation of the prognosis in patients to ICP-related parameters.Results:Pressure reactivity index(PRx)and intracranial pressure(ICP)of favorable prognosis group were significantly higher than those of unfavorable prognosis group(t=12.27,t=5.22,p<0.05).Meanwhile,cerebral perfusion pressure(CPP)and ICP-ABP wave amplitude correlation(IAAC)of favorable prognosis group were significantly lower than those of unfavorable prognosis group(t=14.54,t=14.78,p<0.05).The average age,gender,duration of admission to neurosurgical intensive care unit(NICU)and GCS(Glasgow coma scale)score on admission of the two groups were not statistically significant.Conclusions:The prognosis and ICP-related parameters(such as PRx,ICP,CPP,etc.)in patients with craniocerebral injury are risk factors for the prognosis effect.Therefore,to monitor the above-mentioned indicators has an important clinical value for assessing the prognosis of craniocerebral injury.

Clinical significance of large decompressive craniectomy to control intractable increased intracranial pressure in patients with traumatic brain injury

Objective To investigate the role of decompressive craniectomy (DC) to decrease intractable intracranial hypertension(ICH) due to diffuse brain swelling and / or cerebral edema after severe traumatic brain injury and the time window of DC to affect on prognosis. Methods The clinical record of 132 patients who underwent DC for posttraumatic intractable ICH in our hospital from July 2003 to

Effects of positive end-expiratory pressure on intracranial pressure,cerebral perfusion pressure,and brain oxygenation in acute brain injury:Friend or foe?A scoping review

Background Patients with acute brain injury(ABI)are a peculiar population because ABI does not only affect the brain but also other organs such as the lungs,as theorized in brain–lung crosstalk models.ABI patients often require mechanical ventilation(MV)to avoid the complications of impaired respiratory function that can follow ABI;MV should be settled with meticulousness owing to its effects on the intracranial compartment,especially regarding positive end-expiratory pressure(PEEP).This scoping review aimed to(1)describe the physiological basis and mechanisms related to the effects of PEEP in ABI;(2)examine how clinical research is conducted on this topic;(3)identify methods for setting PEEP in ABI;and(4)investigate the impact of the application of PEEP in ABI on the outcome.Methods The five-stage paradigm devised by Peters et al.and expanded by Arksey and O'Malley,Levac et al.,and the Joanna Briggs Institute was used for methodology.We also adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)extension criteria.Inclusion criteria:we compiled all scientific data from peer-reviewed journals and studies that discussed the application of PEEP and its impact on intracranial pressure,cerebral perfusion pressure,and brain oxygenation in adult patients with ABI.Exclusion criteria:studies that only examined a pediatric patient group(those under the age of 18),experiments conducted solely on animals;studies without intracranial pressure and/or cerebral perfusion pressure determinations,and studies with incomplete information.Two authors searched and screened for inclusion in papers published up to July 2023 using the PubMed-indexed online database.Data were presented in narrative and tubular form.Results The initial search yielded 330 references on the application of PEEP in ABI,of which 36 met our inclusion criteria.PEEP has recognized beneficial effects on gas exchange,but it produces hemodynamic changes that should be predicted to avoid undesired consequences on cerebral blood flow and intracranial pressure.Moreover,the elastic properties of the lungs influence the transmission of the forces applied by MV over the brain so they should be taken into consideration.Currently,there are no specific tools that can predict the effect of PEEP on the brain,but there is an established need for a comprehensive monitoring approach for these patients,acknowledging the etiology of ABI and the measurable variables to personalize MV.Conclusion PEEP can be safely used in patients with ABI to improve gas exchange keeping in mind its potentially harmful effects,which can be predicted with adequate monitoring supported by bedside non-invasive neuromonitoring tools.

Intracranial pressure is elevated at 24h post-stroke inmice

Background:It has long been assumed that post-stroke intracranial pressure(ICP)elevation occurs because of large infarct and edema volumes.However,we have repeatedly shown IcP elevation at 24 h post-stroke in the presence of little to no edema in rats.Biological processes are often conserved across species and types of injury.Therefore,we aimed to determine if an ICP rise occurs at 24 h post-stroke in the presence of small infarct and edema volumes in mice.Methods:Mice were randomized by random number table to either photothrombotic stroke or sham surgery(n=15).Epidural ICP was recorded using a fiber optic catheter at 1 h post-stroke(baseline)and between 23 and 24hpost-stroke.Results:ICP was significantly higher at 24 h compared to baseline in stroke animals(n=6;10.71±6.45mmHg vs.3.74±2.20mmHg,respec-tively;p=0.03).ICP at 24 h was also significantly higher in stroke mice compared to sham(n=6;3.45±1.43mmHg;p=0.02).There was no change in ICP in sham mice(p=0.9).Edema volumes in stroke animals were small(0.04±0.04 mm3)and unlikely to have caused significant ICP elevation.Conclusion:This study provides evidence of an edema-independent ICP elevation following small ischemic stroke in mice.The occurrence of this rise supports our findings in other species and suggests it is caused by a previously undescribed mechanism.

ICP-MS测定川滇黔相邻区高岭石黏土岩矿物中伴生关键三稀元素的前处理方法研究

在川滇黔相邻区峨眉山玄武岩顶部与宣威组底部之间发育一套厚度较为稳定的风化壳,主要为高岭石黏土岩,富集有三稀元素。为弄清其品位及含量,本文采用XRD衍射分析、XRF分析主次量元素,选用几种熔矿前处理进行对比,试液用电感耦合等离子质谱(ICP-MS)测定。实验结果表明:①试样矿物组成主要为高岭石、锐钛矿、伊利石、钛铁矿、板钛矿等,其中高岭石占比62.3%~89.85%,锐钛矿占比2.50%~11.8%,伊利石占比1.8%~18.0%,钛铁矿占比0.10%~1.00%,板钛矿占比0.70%~7.00%,其主量元素主要为Si、Al、Fe、Ti。②微波消解法较适用于Sc的消解处理,但对于Nb和Zr元素,数据偏低,其余差异性不显著。③碱熔-沉淀分离法较适用于难溶矿物分解,不仅打开矿物晶格,且在沉淀剂或络合剂的作用下,实现纯化试液目的,有效降低基体干扰,提高数据准确性,较适用于Pr、Nd、Tb、Dy、Nb、Zr元素的方法前处理;④碱熔-熔融物酸化法适用于Ga的熔矿前处理,在KED模式下,有效降低背景干扰,提高了准确性。体系方法检出限介于0.011~1.66μg/g之间,测定下限介于0.044~6.65μg/g之间,RSD介于2.06%~11.1%之间,RE介于0.99%~9.90%之间。经实际样品验证,方法较适用于该地区试样中关键三稀元素的测定。

NO代谢产物在中重型颅脑损伤患者中的变化探析及与ICP和GCS评分的关系研究

探讨NO代谢产物在中重型颅脑损伤患者中的变化及其与颅内压(ICP)和格拉斯哥昏迷(GCS)评分的关系。选择中南大学湘雅二医院桂林医院2018年1月—2022年12月收治的132例中重型颅脑损伤患者为研究对象,根据Fisher CT分级将患者分为1~2级组和3~4级组;根据预后将患者分为预后良好组和预后差组。测量患者ICP并检测各组NO代谢产物;采用GCS评分进行评估,比较各组的NO代谢产物、ICP及GSC评分,对中重型颅脑损伤患者预后进行多因素Logistic回归分析,对患者NO代谢产物与ICP和GCS评分进行相关性分析。研究发现,NO代谢产物在中重型颅脑损伤患者中呈高表达,与ICP和GCS评分存在相关性,三者均与患者预后存在紧密的联系。

密闭高温高压消解ICP-AES法同时测定白茶中的12种金属元素

用密闭高温高压消解-电感耦合等离子体原子发射光谱(ICP-AES)法测定白茶中铝、镉、钴、铬、铜、镁、锰、镍、铅、锡、锶、钙12种元素,对用三种混合酸消解液在高压密闭罐中消解样品进行了实验,确定王水对样品的前处理效果最好。各元素标准曲线的线性回归方程相关系数均大于0.999;检出限在0.0001~0.025mg/L之间,相对标准偏差(RSD)<4.5%,回收率为91.9%~106%。该方法操作简便,用酸量少降低对环境的危害,精密度高、检测结果可靠。

高压密闭消解-电感耦合等离子体质谱(ICP-MS)法测定青藏高原气溶胶样品中磷及其他18种元素

气溶胶中磷(P)的准确测定是评估磷沉降对青藏高原生态效应及磷的生物地球化学循环的重要前提。针对青藏高原气溶胶中磷含量低及滤膜单个样品量有限的特征,建立了高压密闭消解-电感耦合等离子体质谱(ICP-MS)法测定气溶胶中磷及其他元素含量的方法。实验表明,P的检出限为3.5μg/L,优于电感耦合等离子体发射光谱仪(ICP-OES)的检出限(89μg/L),其他元素检出限均为0.013~36μg/L,部分元素如Co、Cd、Pb等为2~7 ng/L。各元素线性关系良好,测定结果的相对标准偏差(RSD)<5%,磷的加标回收在90.0%~103%,方法准确度和精密度满足分析要求,成功地测定了青藏高原实际气溶胶样品中磷及其他元素,具有良好的可靠性和实用性。