Value of transcranial Doppler indices in predicting raised ICP in infantile hydrocephalus

Cerebral hemodynamic changes in infants with progressive hydrocephalus have been studied with the transcranial Doppler (TCD) technique. Several authors have referred to the correlation between the hemodynamic changes and increased intracranial pressure (ICP). Despite conflicting conclusions on the value of pulsatility index (PI) measurements for monitoring infantile hydrocephalus, these pulsatility indices are the most commonly used for this purpose. Although clinical signs of raised ICP are highly variable and unreliable in infants, assumptions have been made in most of the studies about the presence of elevated ICP on the basis of the patient's clinical state. Few studies have reported on actual ICP values, however, and a direct relationship between ICP and TCD changes has never been adequately demonstrated. In the present study, this relationship was investigated in long-term simultaneous TCD/ICP measurements, in an attempt to develop a noninvasive method of monitoring the effect of ICP on intracranial hemodynamics. Two groups of data sets were established. Group I consisted of pre- and postoperative (shunt implantation) TCD/ICP measurements. Group II were long-term simultaneous TCD/ICP recordings showing significant ICP variations. In most of the postoperative measurements there was a decrease in the average PI and RI values. The correlation between PI or RI and ICP in the long-term simultaneous recordings, however, was generally poor. The risk of obtaining false positive or false negative PI or RI values in short-term measurements was also demonstrated. It can be concluded from our results, besides the wide range of reference values for the Doppler indices and extracranial influences upon them, that the present Doppler indices are inadequate for monitoring the complex intracranial dynamic responses in patients with raised ICP.     

Radiation leukoencephalopathy associated with moderate hydrocephalus: intracranial pressure monitoring and results of ventriculoperitoneal shunting

Delayed neurological sequelae of radiotherapy have several manifestations; leukoencephalopathy is one of the most common. Pathogenetic relationships between radiation leukoencephalopathy and other findings of diffuse radiation injury (brain atrophy and progressive ventriculomegaly) are not well defined. Moreover, no guidelines have been established for the treatment of hydrocephalus when associated with radiation leukoencephalopathy. Our study reportsintracranial pressure (ICP) monitoring in two patients with radiation leukoencephalopathy with moderate hydrocephalus. High intraventricular mean pressure and high peaks were found, and marked improvement of clinical status after shunting was achieved. This study, although restricted to only two patients, shows that ventriculoperitoneal shunting insertion is useful in radiation-induced hydrocephalus, when ICP monitoring detects high mean pressure. A hypothesis is advanced concerning radiation-induced hydrocephalus with high ICP, emphasizing periventricular astrocytosis and its connections with cerebral compliance. Received: 27 April 2002 / Accepted in revised form: 22 July 2002     

Intracranial pressure and cerebral arterial flow velocity indices in childhood hydrocephalus: current review

Because of its noninvasive and repeatable nature, Doppler ultrasound has been increasingly used to assess changes in cerebral haemodynamics in infants and children with hydrocephalus. There is general agreement that a direct correlation exists between the intracranial pressure (from experimental, fontanometric and direct measurement evidence) and the resistance index. In addition, this increasing index has been predominantly due to a reduction in the end-diastolic velocity. Stable ventriculomegaly is associated with normal pulsatility. The cerebral blood flow velocity parameters change significantly following CSF drainage by tapping or shunting. The measurement of intracranial pressure and cerebral blood flow velocity are currently the best ways of assessing the need for CSF diversion and monitoring subsequent shunt function.Presented at the Consensus Conference: Hydrocephalus '92, Assisi, Italy, 26–30 April 1992     

脑出血患者经颅多普勒超声评估颅内压变化研究

目的 为进一步验证脑出血患者颅内压（intracranial pressure,ICP）与经颅多普勒超声（transcranial Doppler ultrasound,TCD）血流参数间的相关性,确立脑出血患者TCD血流参数预测ICP的最优数学模型 并评价其预测准确性。 方法 根据纳入、排除标准,共登记22例脑出血患者的人口学资料、主要神经功能评分和病灶特征 资料,所有患者行持续床旁脑实质颅内压监测,期间每天复查TCD,监测大脑中动脉（middle cerebral artery,MCA）及颈内动脉（internal carotid artery,ICA）血流参数并记录即时ICP数值、体温、血压、心 率和血氧饱和度等。筛选最优TCD血流参数,对即时ICP与TCD血流参数行相关性分析及多元线性回归 分析,建立TCD参数评估ICP数学模型,并对其诊断颅高压（ICP>15 mmHg）的准确性进行评价。 结果 相关性分析示脉搏指数（pulsatility index,PI）与ICP呈正相关,相关系数为r =0.66（P <0.01）。 TC D血流参数预测I C P数学模型为I C P e =-16.8+26.8×P I+0.12×V m,调整R 2为0.46;颅高压 （ICP>15 mmHg）时,ICPe的曲线下面积为0.93,95%可信区间为0.88～0.97。 结论 TCD血流参数PI与ICP呈正相关,是预测ICP最重要的指标。ICPe=-16.8+26.8×PI+0.12×Vm（调 整R2为0.46）可准确诊断颅高压（I CP>15 mmHg）。     

Analysis of intracranial pressure pulse wave in experimental hydrocephalus

Much has been written about the relationship between the pulse pressure (PP) of the intracranial pressure pulse wave (ICPPW) and ventricle dilatation. Some data suggest that high PP is the cause of ventricle dilatation, and other authors have reported that high PP results from decreased intracranial compliance. In order to clarify these points, the amplitude of PP and pressure-volume response (PVR: an indicator of intracranial complicance) were measured in bilateral ventricles using Hochwald's hydrocephalic model (right-left difference in ventricle size is clear due to hemicraniectomy). Hydrocephalus was induced by means of intracisternal injection of a kaolin powder solution to dogs. The mean ICP, amplitude of the PP, PVR and ventricle size (estimated by MR imaging) were evaluated in pathologic conditions induced by the following procedures. Group A, control: kaolin-induced hydrocephalus without craniectomy; group B: kaolin-induced hydrocephalus with right-sided craniectomy; group C: kaolin-induced hydrocephalus with right-sided craniectomy and dural resection; group D: kaolin-induced hydrocephalus with right-sided craniectomy, dura resection and temporal muscle resection. Using MR imaging, the same degree of symmetrical ventricle dilatation was identified in all groups except group D. Group D alone demonstrated a difference in ventricular size (craniectomy side > non-craniectomy side). There was no appreciable difference in mean ICP between any two groups. However, the amplitude of PP and the PVR decreased stepwise from group A to group D. The difference in the amplitude of the PP and PVR between the right and left ventricles was not significant in any group. Even on the larger ventricle side (right) in group D, the amplitude of PP was the same as that of the left ventricle, and much smaller than in other groups. The results of our research suggest that: (1) There was no relation between ventricle dilatation and the amplitude of PP. This means that the increased amplitude of PP was not the cause of the ventricle dilatation in this model. (2) A high degree of correlation exists between the amplitude of PP and the PVR. This means that PP can be a good parameter of intracranial compliance in this modelPresented at the Consensus Conference: Hydrocephalus '92, Assisi, Italy, 26–30 April 1992     

Complications of elective intracranial pressure monitoring in adult hydrocephalus

Continuous invasive monitoring of intracranial pressure (ICP) can be used in the diagnosis and management of various types of chronic cerebrospinal fluid (CSF) circulation disorders, such as hydrocephalus, shunt dysfunction and idiopathic intracranial hypertension. The risk profile and incidence of adverse events of this surgical procedure in this patient population is not well established. We aimed to investigate and describe the risks of ICP monitoring in adult patients with chronic CSF circulation disorders. We analysed 152 patients undergoing continuous ICP monitoring between 2010 and 2019, mainly for idiopathic normal pressure hydrocephalus. The average duration of ICP monitoring was 17 h 51 min. We observed no major adverse events, such as symptomatic intracranial haemorrhage, intracranial infection, or persistent neurological deficit. Minor complications were seen in 7% of patients and included accidental removal of the ICP probe in 4 patients, inability to remove the probe requiring surgical removal in 2 patients and single generalised seizures in 2 patients. In summary, the risk of serious adverse events and complications from invasive ICP monitoring in chronic CSF circulation disorders in adult patients appears to be low.     

The influence of head position on the intracranial pressure in preterm infants with posthemorrhagic hydrocephalus

In order to measure the intracranial pressure (ICP) of 8 newborn with posthemorrhagic hydrocephalus (group A) we used the noninvasive technique via the anterior fontanel (Ladd monitor). The ICP was monitored in two different head positions (30° elevated, horizontal). The median measurements were: elevated head position, 13 mm Hg, horizontal head position, 16 mm Hg. For comparative reasons, we also measured the ICP of 12 healthy newborns (group B). The median results were: elevated head position, 4 mm Hg, horizontal head position, 6.5 mm Hg. Significant differences were found between groups.     

Static and pulsatile intracranial pressure in idiopathic intracranial hypertension

Objective

The aim of this observational study was to characterize the static and pulsatile intracranial pressure (ICP) in conservatively (medically) treated idiopathic intracranial hypertension (IIH) patients in need of shunt surgery, and also in patients with chronic daily headache (CDH) without visual disturbances.

Methods

The material includes 14 IIH patients and 7 CDH patients in whom ICP was monitored continuously over-night. Static ICP was characterized by mean ICP, pulsatile ICP was characterized by the wave amplitude, rise time, and rise time coefficient.

Results

In the IIH group all 14 had headache and visual disturbances. Mean ICP was high (>15 mmHg) in only 7 patients (50%), while mean ICP wave amplitude was high (≥4 mmHg) in all 14 (100%). All IIH patients were shunted and improved clinically thereafter (i.e., relief from visual disturbances and/or headache). None in the CDH group had high mean ICP or mean ICP wave amplitude, and none were shunted.

Conclusions

In this cohort of 14 conservatively treated IIH patients with lasting and shunt-responsive headache and visual disturbances, the mean ICP wave amplitude was elevated (≥4 mmHg) in all patients despite normal mean ICP (<15 mmHg) in 7 patients (all but one on medication). Therefore, the pulsatile ICP may be more relevant than the static ICP in the diagnostic setting for patients with IIH. Further prospective standardized approaches are warranted.     

Pediatric intracranial pressure monitoring in hypoxic and nonhypoxic brain injury

We reviewed the results of all pediatric patients undergoing intracranial pressure (ICP) monitoring in a 2-year period at our institution. The outcome of patients suffering hypoxia or ischemic injuries (HII) is compared to those suffering non-hypoxic or non-ischemic injuries (NHII). Thirty-four patients had ICP monitors placed during the study period. Inconplete patient information led to the exclusion of 5 patients. An additional 5 patients were excluded because no measures to control ICP were taken after the monitor was placed. Twenty-four patients required treatment for raised ICP (hyperventilation, 24; mannitol, 19; barbiturate coma, 6). Admission Glasgow Coma Score in patients suffering HII (median score 5) and NHII (median score 6) were not significantly different (Mann-Whitney U Test). Only 2 of 8 patients with HII were near-drowning vietims. The remaining 6 had HII from other causes (5 survivors of various forms of asphyxia and 1 of cardiac arrest). All 8 patients had poor outcomes (1 severely disabled; 7 died). The 16 patients with NHII had a variety of diagnoses (6 trauma, 5 encephalitis, 4 bacterial meningitis, 1 diabetic ketoacidosis). Among these, 6 had good outcomes and 10 poor outcomes (2 severely disabled, 2 vegetative, and 6 died). The difference in outcome between patients with NHII and HII is significant at P=0.059 (Fischer Exact test). Patients with NHII may benefit from ICP monitoring. Patients with HII from near-drowning and other causes did not appear to benefit from ICP monitoring and interventions directed at controlling ICP.     

The light-flash-evoked response as a possible indicator of increased intracranial pressure in hydrocephalus

Surgical treatment of infantile hydrocephalus by shunt implantation may result in suboptimal intracranial pressure. Major neurological impairments and death are usually prevented by shunt treatment, but minor sequelae may persist or develop. The introduction of adjustable shunts has improved the possibilities of optimizing shunt function and minimizing the risk of such impairments. However, it is still impossible to determine the intracranial pressure without invasive measurements. Clinical findings and procedures such as computed tomography (CT) are not always enough to allow a conclusion as to whether a child's signs and symptoms are the result of suboptimal intracranial pressure (shunt dysfunction) or are of another etiology. With the aim of reducing the number of invasive pressure measurements and CT scans, we investigated the effect of increased intracranial pressure on the visual evoked response (VER). Binocular light flash stimuli of supramaximal intensity were used and VER recordings were performed from Oz and Cz. The VER results from a group of 31 infants and children with hydrocephalus and 2 children with pseudotumor cerebri were compared with responses from a control group of 35 healthy children. The results show that a subpotential, P (P-prime), usually just preceding P1 (P100), has an increased latency (>96 ms) in all hydrocephalic children before surgery. The P latency in this group was usually even above 110 ms. The latencies of other VER potentials were also increased but not as consistently as P. After surgical intervention the VER latencies decreased and usually normalized. The P latency in four children in the control group was just above the borderline latency, but was less than 110 ms. In the remaining 31 children the VER P latency was 96 ms or below. The VER provides information about the physiological condition of the visual system and seems to be related to intracranial pressure. The method was found to be useful in the clinical examination of hydrocephalic children. In addition, the VER may be used to monitor patients' clinical condition and the effect of treatment, e.g., in cases of pseudotumor cerebri or traumatic brain injury.     

Transcranial Doppler can predict intracranial hypertension in children with severe traumatic brain injuries

Purpose  

The purpose of this study is to evaluate the accuracy of emergency Transcranial Doppler (TCD) to predict intracranial hypertension and abnormal cerebral perfusion pressure in children with severe traumatic brain injury (TBI).     

Evaluation of cerebral blood flow changes by transfontanelle Doppler ultrasound in infantile hydrocephalus

Doppler ultrasound investigation of cerebral blood flow velocity was performed in hydrocephalic infants through the anterior fontanelle. Systolic (S) and end-diastolic (D) frequency values recorded on the anterior cerebral artery were used to define the pulsatility index (PI) calculated from the equation PI=S-D/S. Comparison between systolic, end-diastolic and pulsatility index values of 50 normal infants and 10 hydrocephalic infants showed a statistically significant difference (P<0.05) for systolic and pulsatility index values. However, no significant difference was found for end-diastolic values. The authors believe that the phenomenon could be explained as an increase of the cerebrovascular compliance which counteracts the increase of the perivascular pressure in an attempt to maintain a normal cerebral blood flow. Therefore, the transfontanelle Doppler ultrasound technique may provide a useful and early tool in diagnosing cerebral blood-flow changesin hydrocephalic infants.     

Kaolin-induced hydrocephalus in the hamster: temporal sequence of changes in intracranial pressure, ventriculomegaly and whole-brain specific gravity

The development of kaolin-induced hydrocephalus in adult hamsters was monitored by measuring changes in intracranial pressure (ICP), ventriculomegaly (VG) and whole-brain specific gravity (SG). Controls were intact or sham operated animals. Relative to controls, ICP of experimental animals increased at 24 h post intracisternal kaolin injection (by approximately 7-fold), reached a maximum on day 6 (by approximately 12-fold) and remained markedly elevated through day 15 (by approximately 5-fold). Ventricles differed in time of onset of distension (third: day 1, lateral: day 2, fourth: day 4) and in time of maximum ventriculomegaly (fourth: day 6; third: day 7; and lateral: day 9). Ventricular distension resulted in alterations in the ependyma; cilia were lost and apical cell surfaces were distorted. The ependyma was ruptured and the subjacent neuropil was exposed to the cerebrospinal fluid in some regions. Whole-brain SG remained constant in controls but declined in hydrocephalic hamsters after day 3 post-kaolin injection and reached its nadir on day 9 when whole-brain water content was 18% greater than in controls. Consistent with the fact that causal relationships exist between increased ICP, ventricular distension and brain edema, the alterations in each parameter occurred sequentially rather than simultaneously, and the time-course of each manifestation of hydrocephalus differed. The data suggest that the pathophysiology of kaolin-induced hydrocephalus in the hamster is tri-phasic: an initial period of rapid change, a brief interval of maximum alteration, and a subsequent period of compensation. Received: 4 June 1998 / Revised: 30 September 1998, 7 January 1999 / Accepted: 8 January 1999     

Influence of body position on tissue-pO2, cerebral perfusion pressure and intracranial pressure in patients with acute brain injury

Abstract

ft is a common practice to position head-injured patients in bed with the head elevated above the level of the heart in order to reduce intracranial pressure OCP). This practice has been in vivid discussion since some authors argue a horizontal body position will increase the cerebral perfusion pressure (CPP) and therefore improve cerebral blood flow (CBF). However, ICP is generally significantly higher in the horizontal position. The aim of this study was to evaluate changes in regional microcirculation using tissue pO ² (ti-p0₂), as well as changes in cerebral perfusion pressure (CPP) and intracranial pressure induced by changes in body position in patients with head injury. The effect of 0° and 30° head elevation on ti-p0₂, CPp, ICP and arterial blood pressure (MABP) was studied in 22 head injured patients during day 0-12 after trauma. The mean ICP was significantly lower at 30° head elevation than at 00 (74.1 + 8.6 vs. 19.9+8.3 mmHg). While MABP was unaffected by head elevation, CPP was slightly higher at 300 than at 0° (76.5+ -13.5 vs. 71.5+ 13.2 mmHg). However, regional ti-p0₂ was unaffected by body position (30° vs. 0°: 24.9+73.1 vs. 24.7 + 12.9 mmHg). fn add~tion, there was no change in the time course after trauma concerning these findings in the individLfal pati,ents. The data indicate that a moderate head elevation of 300 reduces ICP without jeopardizing regional cerebral microcirculation as monitored using a polarographic ti-p0₂ microcatheter. [Neural Res 1997; 19: 249-253]     

Effects of thiopental on middle cerebral artery blood velocities: a transcranial Doppler study in children

The effect of an intravenous injection of thiopental on middle cerebral artery blood velocities was assessed by transcranial pulsed Doppler monitoring in 20 children: ten head-injured patients and ten control subjects. Thiopental induced a moderate but immediate decrease of middle cerebral artery blood velocities in both groups; this variation was significant (P<0.01) and more prolonged in the head-injured than in control patients. Transcranial Doppler ultrasonography thus appears to be suitable for monitoring children in intensive care units and could help to avoid the use of thiopental in patients with low cerebral artery blood flow velocity.     

The intraocular pressure could not be used to determine the intracranial pressure in patients with hydrocephalus

Purpose: An accurate intracranial pressure (ICP) measurement is vital for patients with hydrocephalus. ICP is generally measured by lumbar puncture opening pressure, which is invasive and has potential adverse side effects. Intraocular pressure (IOP) was investigated to measure ICP indirectly; however, its accuracy was controversial. We conducted this retrospective study to investigate whether IOP can be used as a surrogate for ICP in hydrocephalus patients.

Methods: We performed a retrospective study enrolled 50 cases, including 32 patients with normal pressure hydrocephalus (NPH) and 18 patients with high pressure hydrocephalus (HPH). The independent factors of ICP, the correlation between ICP and other factors, and diagnostic value of IOP and papilledema to predict ICP were analysed, respectively.

Results: Patients with HPH were more likely suffered from visual deterioration (33.33% vs. 9.38%, p?=?.045) and papilledema (55.56% vs. 3.13%, p?=?.001). Multivariate analysis revealed that papilledema was a significant factor (OR =40.765, 95%CI 3.331–498.846, p?=?.004). Pearson’s correlation analysis indicated that ICP did not correlate with any other factors.

Conclusions: IOP was not an independent factor of ICP in patients with hydrocephalus, and could not be used to determine IOP. Papilledema might be a significant factor of ICP in hydrocephalus sufferers. Compared with NPH patients, patients with HPH were more prone to develop papilledema.     

Doppler flow velocity measurements in patients with intracranial hypertension

Summary In patients with severe brain lesions monitoring of the intracranial pressure as well as monitoring of cerebral blood flow can be of clinical value. While at the moment there is no atraumatic method for measuring cerebral blood flow in man, it is recommended to measure blood flow velocity with the ultrasound Doppler technic in the common carotid artery. On theoretical grounds a positive correlation between cerebral blood flow and blood flow velocity can be expected and the observations presented show that such a correlation exists in normal controls and in neurological patients. In many neurological patients the flow velocity in the common carotid artery decreases with increasing intracranial pressure. This suggests that the autoregulation is disturbed. The demonstration of such a disturbance can have clinical implications.

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Zusammenfassung Bei Patienten mit ernsten Läsionen im Gehirn kann Monitoring von sowohl intercraniellem Druck als auch der zerebralen Blutdurchströmung für die Klinik von Bedeutung sein. Da im Moment keine atraumatische Methode für die Messung der zerebralen Blutdurchströmung besteht, wird anempfohlen, die Durchströmungsgeschwindigkeit mit der Ultraschall-Doppler-Technik in der Arteria carotis communis zu messen. Theoretisch kann eine positive Korrelation zwischen der zerebralen Blutdurchströmung und der Strömungsgeschwindigkeit erwartet werden.Die beschriebenen Ergebnisse zeigen, daß tatsächlich ein solcher Zusammenhang besteht, sowohl bei gesunden Versuchspersonen als auch bei neurologischen Patienten.Bei vielen dieser Patienten nimmt die Durchströmungsgeschwindigkeit in der Arteria carotis communis ab bei einer Zunahme des intracraniellen Druckes. Dies suggeriert eine gestörte Autoregulation. Das Aufzeigen einer solchen Störung kann klinische Bedeutung haben.

     

颅内压监测在急性颅脑损伤救治中的应用进展

急性颅脑损伤的发生率日益提高,严重的颅脑损伤极大威胁国民健康水平.急性颅脑损伤后7d内最主要的致死原因为颅内压(ICP)增高,控制ICP是急性颅脑损伤处理的重要前提.ICP监测可迅速及准确地反应急性颅脑损伤患者的颅内压力情况,有效反应急性颅脑外伤患者的病情变化,现已广泛用于急性颅脑损伤的救治.ICP监测技术主要分为有创性和无创性两大类,无创性ICP监测具有低感染率等一系列优势,有创性ICP监测虽有感染、出血等风险,但由于其能直观反映ICP变化,故目前仍具有不可替代的优势.ICP监测在急性颅脑损伤的救治中具有协助诊断、为治疗提供量化依据以及判断预后等重要作用.对降低急性颅脑损伤患者的病死率和致残率,改善患者的预后,有效地提高急性颅脑损伤患者的抢救成功率、治愈率具有重要意义.     

Intracranial pressure monitoring using a programmable pressure valve and a telemetric intracranial pressure sensor in a case of slit ventricle syndrome after multiple shunt revisions

A case of hydrocephalus showing slit ventricle syndrome after multiple shunt revisions was treated with a programmable pressure valve, and intracranial pressure was monitored with a telemetric sensor. High pressure setting produced positive and normal values of intracranial pressure in this patient. We report our experiences.     

Evaluation of intracranial pressure from transcranial Doppler studies in cerebral disease

Summary The extent to which estimations of intracranial pressure can be derived from intracranial flow patterns was studied. The blood flow velocity in the middle cerebral artery was recorded with the EME TC 2–64 transcranial Doppler (TCD) device in 26 patients suffering from various severe cerebral diseases. Simultaneously the mean intracranial pressure (ICP) was measured by means of an epidural device. Arterial carbon-dioxide tensions were monitored by blood gas analysis. In all patients it was observed that the middle cerebral artery flow patterns changed distinctly when the ICP increased; these changes were distinguished by a decrease of the mean flow velocity and an increase of the Pourcelot index. A good correlation between the ICP and the flow parameters (especially the product mean systemic arterial pressure × Pourcelot index/mean flow velocity) was found in a select group of 13 patients, in whom comparable initial conditions existed and in whom additional parameters influencing the TCD recordings could be kept constant (r=0.873; P<0.001).Supported by the Deutsche Forschungsgemeinschaft (SFB 330 — Organprotektion)