Intracranial Pressure Monitoring In Patients Research Articles

Accuracy of Noninvasive Intracranial Pressure Monitoring in Patients with Subarachnoid Hemorrhage

Abstract Background: Subarachnoid hemorrhage (SAH) can lead to elevated intracranial pressure (ICP), which poses significant risks of morbidity and mortality. Monitoring ICP is crucial for the early detection and management of these complications in patients with aneurysmal SAH (aSAH). Traditional invasive ICP monitoring techniques, while effective, carry risks associated with infection and other complications. The Schmidt method, a noninvasive ICP monitoring technique, has emerged as a potential alternative to provide reliable measurements without the inherent risks of invasive methods. Methods: From January 2018 to December 2023, the authors performed both invasive (intraventricular catheters) and noninvasive (Schmidt method) ICP monitoring in patients with aSAH and Hunt and Hess (H and H) scores of 3–5. Patients requiring emergent craniotomy, with serious medical comorbidities or coagulopathies, or with noncompliance were excluded from the study. The accuracy and efficacy of the Schmidt method were evaluated by comparing the results of noninvasive monitoring with the results of invasive ICP monitoring. Results: Out of 238 cases with aSAH referred to our neurosurgical center, 105 had H and H scores of 3–5. Noninvasive ICP monitoring using the Schmidt method was performed in 86 cases (48 females, 38 males; mean age 68 ± 8 years). The mean ICP measured by the invasive method was 15.2 ± 6.2 mmHg, whereas the mean ICP measured by the noninvasive method was 16.6 ± 5.4 mmHg. The calculated root mean square error was 3.6 mmHg, and the average Pearson correlation between the estimated and real waveforms was 0.96. Conclusion: The findings of this study suggest that the application of the Schmidt method is a reliable and accurate approach for the assessment of ICP in patients with SAH, potentially eliminating the need for invasive ICP monitoring and reducing the associated risks.

Brain tissue oxygen plus intracranial pressure monitoring versus isolated intracranial pressure monitoring in patients with traumatic brain injury: an updated meta-analysis of randomized controlled trials.

Intracranial pressure (ICP) monitoring plays a key role in patients with traumatic brain injury (TBI), however, cerebral hypoxia can occur without intracranial hypertension. Aiming to improve neuroprotection in these patients, a possible alternative is the association of Brain Tissue Oxygen Pressure (PbtO2) monitoring, used to detect PbtO2 tension. We systematically searched PubMed, Embase and Cochrane Central for RCTs comparing combined PbtO2 + ICP monitoring with ICP monitoring alone in patients with severe or moderate TBI. The outcomes analyzed were mortality at 6months, favorable outcome (GOS ≥ 4 or GOSE ≥ 5) at 6months, pulmonary events, cardiovascularevents and sepsis rate. We included 4 RCTs in the analysis, totaling 505 patients. Combined PbtO2 + ICP monitoring was used in 241 (47.72%) patients. There was no significant difference between the groups in relation to favorable outcome at 6months (RR 1.17; 95% CI 0.95-1.43; p = 0.134; I2 = 0%), mortality at 6months (RR 0.82; 95% CI 0.57-1.18; p = 0.281; I2 = 34%), cardiovascular events (RR 1.75; 95% CI 0.86-3.52; p = 0.120; I2 = 0%) or sepsis (RR 0.75; 95% CI 0.25-2.22; p = 0.604; I2 = 0%). The risk of pulmonary eventswas significantly higher in the group with combined PbtO2 + ICP monitoring (RR 1.44; 95% CI 1.11-1.87; p = 0.006; I2 = 0%). Our findings suggest that combined PbtO2 + ICP monitoring does not change outcomes such as mortality, functional recovery, cardiovascularevents or sepsis. Furthermore, we found a higher risk of pulmonaryevents in patients undergoing combined monitoring.

Intracranial Pressure Monitoring in Patients With Traumatic Brain Injury: An Umbrella Review of Systematic Review and Meta-Analysis

Background: The objective of this study is to summarize the evidence in Cochrane and non-Cochrane systematic reviews, the effects, and the benefits of monitoring intracranial pressure (ICP) in patients with head trauma with an indication of ICP monitoringMethods: The process of preparing this overview followed the guidelines established by the Joanna Briggs Institute (JBI) for umbrella reviews. Two independent reviewers evaluated the quality of reporting, bias risk, methodologies, and evidence using three different tools: the Risk of Bias in Systematic Reviews (ROBIS) instrument, Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), and A Measurement Tool to Assess Systematic Reviews (AMSTAR 2). Results: A total of five papers met the criteria for inclusion in the study. These papers consisted of 49 primary research studies and 19 unique primary research studies. One of the SRs indicated that using intracranial pressure (ICP) monitoring led to a reduction in mortality. Two of the SRs had mixed results with temporal variation, while two found no significant difference in mortality with ICP monitoring. It is important to note that the quality of the SRs varied, with some being of higher quality than others.Conclusion: There was no conclusive evidence that ICP monitoring reduces mortality in TBI patients. There was high heterogeneity in included primary research studies. Future research should aim to address the limitations of these studies and provide more conclusive evidence regarding the effectiveness of ICP monitoring in reducing mortality in patients with traumatic brain injury.

Use of invasive intracranial pressure monitoring in patients with severe traumatic brain injury

To evaluate the effectiveness of the use of invasive intracranial pressure (ICP) monitoring on treatment outcomes in patients with severe traumatic brain injury (TBI). We analyzed 50 case histories of patients with severe TBI who received treatment in the Krasnoyarsk Regional Clinical Hospital for the period 2021-2022. Comparisons were made between patients with and without invasive intraventricular ICP monitoring. With the same initial condition of patients, ICP monitoring allows for a faster and more timely response to changes in the clinical condition, which significantly affects the clinical outcome. The use of invasive ICP monitoring improves the outcome of treatment of patients with severe TBI and justifies the money spent on it.

Intracranial Pressure Monitoring in Patients with Severe Traumatic Brain Injury: A Cohort Study with Paired Analysis

Abstract Introduction Intracranial hypertension continues to be the most frequent cause of death in patients with traumatic brain injury (TBI). Thus, invasive monitoring of intracranial pressure (ICP) is a very important tool in neurointensivism. However, there is controversy regarding ICP monitoring and prognosis. Objectives To evaluate whether there is a difference in mortality between patients with severe TBI who underwent invasive ICP monitoring compared with those who did not undergo such procedure. Methodology This is a unicentric study in the prospective cohort mode. A total of 316 patients with severe TBI were evaluated and, out of these 316 individuals, 35 were submitted to ICP monitoring. All clinical data were evaluated by the Tertiary Hospital Neurosurgery team in the city of São Paulo. Results Of the total cohort, 35 (11%) patients underwent ICP monitoring, while 281 did not. Comparing the 2 groups, there was no difference in terms of early mortality between patients who were submitted to monitoring and those who were not (34.3 versus 14.3%; p = 0.09); there was also no difference in terms of hospital mortality (40 versus 28.5%; p = 0.31) or intensive care unit (ICU) length of stay (16.10 days, 95% confidence interval [CI]: 10.6–21.6; versus 20.60 days, 95%CI: 13.50–27.70; p = 0.31). Conclusions In this cohort, we did not identify differences in mortality or in duration of hospitalization between patients with ICP monitoring and those exclusively with clinical-radiological evaluation. However, further national co-operative studies of services using ICP monitoring are needed to achieve results with greater generalization power.

Evaluation of Miethke M.scio Device Implantation for Intracranial Pressure Monitoring in Patients with Cerebrospinal Fluid Disorders

Patients with complex shunt-related problems and varying diagnoses of cerebrospinal fluid (CSF) disturbance can present with headache and clinical symptoms that may be difficult to relate to underdrainage or overdrainage. Telemetric intracranial pressure (ICP) monitoring may assist in evaluating individual patients and assessing shunt function and adjustment. We report a case series of patients receiving a Miethke M.scio sensor. Between June 2016 and August 2021, 14 patients older than 18 years with different diagnoses underwent ventriculoperitoneal shunt surgery and received a Miethke M.scio sensor. Patients had idiopathic intracranial hypertension (n= 3), obstructive hydrocephalus caused by tumors (n= 4), and malformations (n= 5). Headaches (71%) and visual impairment (50%) were the most common symptoms before surgery and 65% of the symptoms were improved after surgery. In total, 25 measurements were made and 11 of these led to changes in the shunt settings. Postoperative measurements were taken in 8 patients and the most common indication of ICP measurement was headache and/or control of the shunt settings. The Miethke M.scio is a safe and valuable device to use in shunt-treated patients, in particular those expected to need assessment of ICP monitoring postoperatively. Repeated ICP measurements can also assist in personalized adjustment of the shunt setting to optimize CSF flow in this diverse patient group. Future studies should include a standardized protocol with ICP measurements correlated to the symptoms and cause of CSF disturbances to provide better understanding of the dynamics of the ICP in each patient.

Current Status of Intracranial Pressure Monitoring in Patients with Severe Traumatic Brain Injury in Korea : A Post Hoc Analysis of Korea Neurotrauma Databank Project with a Nationwide Survey.

This study aimed to investigate the current status of intracranial pressure (ICP) monitoring in patients with severe traumatic brain injury (sTBI) in Korea and the association between ICP monitoring and prognosis. In addition, a survey was administered to Korean neurosurgeons to investigate the perception of ICP monitoring in patients with sTBI. This study used data from the second Korea Neurotrauma Databank (KNTDB). Among the enrolled patients with sTBI, the following available clinical data were analyzed in 912 patients: Glasgow Coma Scale score on admission, ICP monitoring, mortality, and Extended Glasgow Outcome Scale score at 6 months. In addition, we administered a survey, entitled "current status and perception of ICP monitoring in Korean patients with sTBI" to 399 neurosurgeons who were interested in traumatic brain injury. Among the 912 patients, 79 (8.7%) patients underwent ICP monitoring. The mortality and favorable outcome were compared between the groups with and without ICP monitoring, and no statistically significant results were found. Regarding the survey, there were 61 respondents. Among them, 70.4% of neurosurgeons responded negatively to performing ICP monitoring after craniectomy/craniotomy, while 96.7% of neurosurgeons responded negatively to performing ICP monitoring when craniectomy/craniotomy was not conducted. The reasons why ICP monitoring was not performed were investigated, and most respondents answered that there were no actual guidelines or experiences with post-operative ICP monitoring for craniectomy/craniotomy. However, in cases wherein craniectomy/craniotomy was not performed, most respondents answered that ICP monitoring was not helpful, as other signs were comparatively more important. The proportion of performing ICP monitoring in patients with sTBI was low in Korea. The outcome and mortality were compared between the patient groups with and without ICP monitoring, and no statistically significant differences were noted in prognosis between these groups. Further, the survey showed that ICP monitoring in patients with sTBI was somewhat negatively recognized in Korea.

Utility of intracranial pressure monitoring in patients with traumatic brain injuries: a propensity score matching analysis of TQIP data.

Intracranial pressure monitoring (ICPM) is central to traumatic brain injury (TBI) management, but its utility is controversial. The 2016-2017 TQIP database was queried for isolated TBI. Patients with ICPM [(ICPM (+)] were propensity-scorematched (PSM) to those without ICPM [ICPM (-)] and divided into three age groups by years (< 18, 18-54, ≥ 55). PSM yielded 2125 patients in each group. Patients aged < 18years had a higher survival probability (p = 0.013) and decreased mortality (p = 0.016) in the ICPM (+) group. Complications were higher and LOS was longer in ICPM (+) patients aged 18-54years and ≥ 55years, but not in patients aged < 18years. ICPM (+) is associated with a survival benefit without an increase in complications in patents aged < 18years. In patients aged ≥ 18years, ICPM (+) is associated with more complications and longer LOS without a survival benefit.

Intracranial Pressure Monitoring in Patients With Severe Traumatic Brain Injury: Extension of the Recommendations and the Effect on Outcome by Propensity Score Matching.

Intracranial pressure (ICP) monitoring is recommended for patients with traumatic brain injury (TBI) with a Glasgow Coma Scale (GCS) <9 on admission and revealing space-occupying lesions or swelling on computed tomography. However, previous studies that have evaluated its effect on outcome have shown conflicting results. To study the effect of ICP monitoring on outcome after adjustment of patient's characteristics imbalance and determine the potential benefit on patients with higher GCS that deteriorates early or in the absence of computed tomography results suggesting high ICP. We searched for adult patients with TBI admitted between 1996 and 2020 with a GCS <9 on admission or deterioration from higher scores within 24 hours after TBI. Patients were divided into groups if they fulfilled strict (Brain Trauma Foundation guidelines) or extended criteria (patients who worsened after admission or without space-occupying lesions) for ICP monitoring. Propensity score analyses based on nearest neighbor matching was performed. After matching, we analyzed data from 454 patients and 184 patients who fulfilled strict criteria or extended criteria for ICP monitoring, respectively. A decreased on in-hospital mortality was detected in monitored patients following strict and extended criteria . Those patients with a higher baseline risk of poor outcome showed higher odds of favorable outcome if they were monitored. ICP monitoring in patients with severe TBI within 24 hours after injury following strict and extended criteria was associated with a decreased in-hospital mortality. The identification of patients with a higher risk of an unfavorable outcome might be useful to better select cases that would benefit more from ICP monitoring.

Spotlight on the July 12 Issue

#### Notable in Neurology This Week This issue features an article that looks at the indications, management, and effect of intracranial pressure monitoring in patients with spontaneous intracranial hemorrhage; another determines the most important vascular risk factors for inclusion in age-specific dementia risk scores. A featured Historical Neurology article examines respiratory crisis and other respiratory curiosities in the aftermath of encephalitis lethargica, calling attention to central causes of respiratory illness even in pandemics with respiratory viruses. ### Association of Plaque Inflammation With Stroke Recurrence in Patients With Unproven Benefit From Carotid Revascularization ![Graphic][1]</img> In … [1]: /embed/inline-graphic-1.gif

Noninvasive assessment of intracranial pressure using subharmonic-aided pressure estimation: An experimental study in canines.

Intracranial hypertension is a common clinicopathological syndrome in neurosurgery, and a timely understanding of the intracranial pressure (ICP) may help guide clinical treatment. We aimed to investigate the correlation between subharmonic contrast-enhanced ultrasound (SHCEUS) parameters and ICP in experimental canines. A dynamic model of ICP change from 11 mm Hg to 50 mm Hg was established in experimental canines by placing a latex balloon into the epidural space and injecting saline into the balloon. In addition, a pressure sensor was placed in the brain parenchyma to record the changes in ICP. When the ICP stabilized after each increase, subharmonic-aided pressure estimation (SHAPE) technology was performed to obtain the SHCEUS parameters, including the basal venous and adjacent intracranial arterial subharmonic amplitude and SHAPE gradient (subharmonic amplitude in the intracranial artery minus that in the basal vein). The correlation between these parameters and ICP was analyzed. The subharmonic amplitude of the basal vein was negatively correlated with the ICP (r = -0.798), and the SHAPE gradient was positively correlated with the ICP (r = 0.628). According to the guidelines for ICP monitoring in patients with traumatic brain injury, we defined 20 mm Hg, 25 mm Hg, and 30 mm Hg as the cutoff ICP levels. The area under the receiver operating characteristic curve of the basal venous subharmonic amplitude for diagnosing intracranial hypertension ≥20 mm Hg, ≥25 mm Hg, and ≥30 mm Hg was 0.867 (95% confidence interval [CI], 0.750-0.943), 0.884 (95% CI, 0.770-0.954), and 0.875 (95% CI, 0.759-0.948), respectively. The area under the receiver operating characteristic curve of the SHAPE gradient for diagnosing intracranial hypertension ≥20 mm Hg, ≥25 mm Hg, and ≥30 mm Hg was 0.839 (95% CI, 0.716-0.924), 0.842 (95% CI, 0.720-0.926), and 0.794 (95% CI, 0.665-0.890), respectively. SHCEUS parameters are correlated with ICP. The SHAPE technique can assist in evaluating ICP changes in canines, which provides a new idea and method for evaluating ICP.

Intracranial Pressure Monitoring in Patients With Spontaneous Intracerebral Hemorrhage: Insights From the SYNAPSE-ICU Study.

Uncertainties exist regarding the indications, management, and effect of intracranial pressure (ICP) monitoring and treatment on outcome in patients with spontaneous intracranial hemorrhage (ICH). We performed an analysis of patients with spontaneous ICH enrolled in the SYNAPSE-ICU study, an international prospective observational study on the use of ICP monitoring. This study aimed to describe, in a large cohort of patients with spontaneous ICH admitted to the intensive care unit (ICU), the clinical practice of ICP monitoring, the occurrence of intracranial hypertension, and its therapeutic management. We assessed in-hospital mortality and the association between ICP monitoring and 6-month mortality and outcome by a propensity score approach with inverse probability weighting. A total of 587 patients with ICH were included in this study; 281 (47.9%) received ICP monitoring. ICP-monitored patients, compared with nonmonitored patients, were younger (61 vs 67 years; p < 0.001), presented more frequently with both reactive pupils (67.2% vs 55.2%; p = 0.008), with better neurologic status at admission (Glasgow Coma Scale ≤8, 82.3% vs 88.8%; p = 0.038), and received higher therapy intensity level during the ICU stay. In 70.5% (170 out of 241) of ICP-monitored patients, the ICH score was equal to 3 or 4. Nearly half of monitored patients (46.6%) had at least one episode of ICP ≥20 mm Hg during the first week. An intraventricular catheter (53.6%) was the most frequently used device and was associated with fewer episodes of intracranial hypertension compared with the other monitoring devices (43.7% vs 64.9%, respectively). At weighted Cox regression model, ICP monitoring was associated with a significant reduction of 6-month mortality (hazard ratio 0.49 [95% CI 0.35-0.71; p = 0.001), but not with neurologic outcome (odds ratio 0.83 [95% CI 0.41-1.68]; p = 0.6077). ICP monitoring in ICH was utilized mainly in moderately severe cases. ICP monitoring was associated with a reduction of in-hospital and 6-month mortality but did not improve 6-month functional outcomes. Further research and randomized controlled trials to generate higher-level medical evidence to support guidelines regarding ICP use and treatment in patients with ICH are needed. SYNAPSE-ICU: ClinicalTrials.gov NCT03257904.

Intracranial pressure monitoring in patients with acute brain injury in the intensive care unit (SYNAPSE-ICU): an international, prospective observational cohort study

The indications for intracranial pressure (ICP) monitoring in patients with acute brain injury and the effects of ICP on patients' outcomes are uncertain. The aims of this study were to describe current ICP monitoring practises for patients with acute brain injury at centres around the world and to assess variations in indications for ICP monitoring and interventions, and their association with long-term patient outcomes. We did a prospective, observational cohort study at 146 intensive care units (ICUs) in 42 countries. We assessed for eligibility all patients aged 18 years or older who were admitted to the ICU with either acute brain injury due to primary haemorrhagic stroke (including intracranial haemorrhage or subarachnoid haemorrhage) or traumatic brain injury. We included patients with altered levels of consciousness at ICU admission or within the first 48 h after the brain injury, as defined by the Glasgow Coma Scale (GCS) eye response score of 1 (no eye opening) and a GCS motor response score of at least 5 (not obeying commands). Patients not admitted to the ICU or with other forms of acute brain injury were excluded from the study. Between-centre differences in use of ICP monitoring were quantified by using the median odds ratio (MOR). We used the therapy intensity level (TIL) to quantify practice variations in ICP interventions. Primary endpoints were 6 month mortality and 6 month Glasgow Outcome Scale Extended (GOSE) score. A propensity score method with inverse probability of treatment weighting was used to estimate the association between use of ICP monitoring and these 6 month outcomes, independently of measured baseline covariates. This study is registered with ClinicalTrial.gov, NCT03257904. Between March 15, 2018, and April 30, 2019, 4776 patients were assessed for eligibility and 2395 patients were included in the study, including 1287 (54%) with traumatic brain injury, 587 (25%) with intracranial haemorrhage, and 521 (22%) with subarachnoid haemorrhage. The median age of patients was 55 years (IQR 39-69) and 1567 (65%) patients were male. Considerable variability was recorded in the use of ICP monitoring across centres (MOR 4·5, 95% CI 3·8-4·9 between two randomly selected centres for patients with similar covariates). 6 month mortality was lower in patients who had ICP monitoring (441/1318 [34%]) than in those who were not monitored (517/1049 [49%]; p<0·0001). ICP monitoring was associated with significantly lower 6 month mortality in patients with at least one unreactive pupil (hazard ratio [HR] 0·35, 95% CI 0·26-0·47; p<0·0001), and better neurological outcome at 6 months (odds ratio 0·38, 95% CI 0·26-0·56; p=0·0025). Median TIL was higher in patients with ICP monitoring (9 [IQR 7-12]) than in those who were not monitored (5 [3-8]; p<0·0001) and an increment of one point in TIL was associated with a reduction in mortality (HR 0·94, 95% CI 0·91-0·98; p=0·0011). The use of ICP monitoring and ICP management varies greatly across centres and countries. The use of ICP monitoring might be associated with a more intensive therapeutic approach and with lower 6-month mortality in more severe cases. Intracranial hypertension treatment guided by monitoring might be considered in severe cases due to the potential associated improvement in long-term clinical results. University of Milano-Bicocca and the European Society of Intensive Care Medicine.

Real-world appraisal of intracranial pressure monitoring

The management of elevated intracranial pressure (ICP) is an essential component of modern neurocritical care for acute brain injury. Direct and continuous monitoring of ICP has generally been considered the most reliable evaluation of ICP and is an important aspect of care for patients with severe brain injury. ICP monitoring is recommended in the Brain Trauma Foundation guidelines and its use is well established in managing severe traumatic brain injury (TBI). 1 Kolias AG Rubiano AM Figaji A Servadei F Hutchinson PJ Traumatic brain injury: global collaboration for a global challenge. Lancet Neurol. 2019; 18: 136-137 Summary Full Text Full Text PDF PubMed Scopus (29) Google Scholar The deterioration of patients with intracerebral haemorrhage 2 Cordonnier C Demchuk A Ziai W Anderson CS Intracerebral haemorrhage: current approaches to acute management. Lancet. 2018; 392: 1257-1268 Summary Full Text Full Text PDF PubMed Scopus (177) Google Scholar or subarachnoid haemorrhage 3 Macdonald RL Delayed neurological deterioration after subarachnoid haemorrhage. Nat Rev Neurol. 2014; 10: 44-58 Crossref PubMed Scopus (428) Google Scholar might also be associated with increased ICP, indicating the importance of ICP monitoring in these patients. Intracranial pressure monitoring in patients with acute brain injury in the intensive care unit (SYNAPSE-ICU): an international, prospective observational cohort studyThe use of ICP monitoring and ICP management varies greatly across centres and countries. The use of ICP monitoring might be associated with a more intensive therapeutic approach and with lower 6-month mortality in more severe cases. Intracranial hypertension treatment guided by monitoring might be considered in severe cases due to the potential associated improvement in long-term clinical results. Full-Text PDF Intracranial pressure monitoring and unfavourable outcomesI read with interest the Article by Chiara Robba and colleagues,1 who reported the findings of the SYNAPSE-ICU observational study of intracranial pressure (ICP) monitoring in patients with acute brain injury. The BEST TRIP trial2 has been the only randomised controlled trial of ICP monitoring to date, and it showed no benefit of this approach in patients with traumatic brain injury. The BEST TRIP trial, however, appears to be the primary foil for SYNAPSE-ICU. These two studies asked different research questions. Full-Text PDF Intracranial pressure monitoring and unfavourable outcomes – Authors' replyWe thank Randall Chesnut and Leonardo Welling and colleagues for their comments on our Article on the SYNAPSE-ICU observational study.1 Chesnut compared the objectives and outcomes of the study with those of the BEST TRIP randomised trial.2 We agree that the aims of SYNAPSE-ICU were fundamentally different to those of BEST TRIP. In SYNAPSE-ICU, we described practice variation and assessed the effect of intracranial pressure (ICP) monitoring on long-term outcomes. A general question discussed daily in intensive care units is about whether to insert an ICP monitoring device after severe acute brain damage. Full-Text PDF Intracranial pressure monitoring and unfavourable outcomesFor prediction of brain injury, intracranial pressure (ICP) monitoring is deemed essential by evidence-based guidelines.1 However, in resource-poor countries, ICP monitoring can be considered a luxury. For many patients in these regions, the management of intracranial hypertension in acute neurological situations is based on radiological assessment.1 However, findings on imaging do not correlate directly with the occurrence of intracranial hypertension.1,2 Full-Text PDF

A vascular subtraction method for improving the variability of evoked tympanic membrane displacement measurements

Objective. Evoked tympanic membrane displacement (TMD) measurements show a correlation with intracranial pressure (ICP). Attempts to use these measurements for non-invasive monitoring of ICP in patients have been limited by high measurement variability. Pulsing of the tympanic membrane at the cardiac frequency has been shown to be a significant source of the variability. In this study we describe a post processing method to remove the cardiac pulse waveform and assess the impact of this on the measurement and its repeatability. Approach. Three-hundred and sixteen healthy volunteers were recruited for evoked TMD measurements. The measurements were quantified by V m, defined as the mean displacement between the point of maximum inward displacement and the end of the stimulus. A sample of spontaneously pulsing TMDs was measured immediately before the evoked measurements. Simultaneous recording of the ECG allowed a heartbeat template to be extracted from the spontaneous data and subtracted from the evoked data. Intra-subject repeatability of V m was assessed from 20 repeats of the evoked measurement. Results with and without subtraction of the heartbeat template were compared. The difference was tested for significance using the Wilcoxon sign rank test. Main results. In left and right ears, both sitting and supine, application of the pulse correction significantly reduced the intra-subject variability of V m (p value range 4.0 × 10−27 to 2.0 × 10−31). The average improvement was from 98 ± 6 nl to 56 ± 4 nl. Significance. The pulse subtraction technique substantially improves the repeatability of evoked TMD measurements. This justifies further investigations to assess the use of TMD measurements in clinical applications where non-invasive tracking of changes in ICP would be useful.

Intracranial pressure monitoring in patients with severe head injury

The study objective is to evaluate the effectiveness of intracranial pressure (ICP) monitoring in patients with severe head injury in a multispecialty hospital. Materials and methods . A retrospective study included 2343 patients who underwent surgical treatment at the N. V. Sklifosovsky Research Institute of Emergency Medicine between 2012 and 2018. Patients admitted in atonic coma, who died in the space of 48 hours after hospitalization, with intracranial hematoma volume &gt;200 cm3, and older than 65 years were excluded. Additionally, results of conservative therapy in 69 patients with severe cerebral contusion were included. ICP monitoring was performed in 249 patients (22.5 % of all patients who underwent surgery with indications for monitoring and no counterindications). A binary logistic regression model included age, sex, type of intracranial injury, depression of consciousness severity at admittance as variables. For treatment outcomes, odds ratio (OR) with 95 % confidence interval and p &lt;0.05 were calculated. Results . Postoperative mortality among patients without ICP monitoring was 64.6 %, among patients with ICP monitoring — 51.2 %. Probability of death in the patient group without ICP was somewhat higher than among patients who underwent ICP (odds ratio (OR) 1.74; 95 % confidence interval (CI) 1.31—2.34). No significant differences were observed in outcomes between patients with or without ICP monitoring for level of consciousness of 4—6 points per the Glasgow Coma Scale (OR 1.01; 95 % CI 0.43—2.37). Among patients with 7—8 points per the Glasgow Coma Scale, outcomes were significantly better among patients who underwent ICP monitoring (OR 1.65; 95 % CI 1.23—2.20). In patients with acute epidural hematomas (AEH), time to death was significantly different: in patients with 7—8points per the Glasgow Scale it was 15 days, with ICP monitoring 52 days; for patients with 4—6points it was 7 and 39 days, respectively. Among patients with multiple hematomas who underwent surgery in moderate coma, outcomes of surgical treatment were a little better with ICP monitoring (OR 1.82; 95 % CI 1.09—3.41). Time to death was significantly different: in patients without ICP monitoring it was 16 days, in patients with ICP monitoring it was 29 days. In patients with microfocal cerebral contusions, probability of death with ICP monitoring was 40 % lower than among patients without ICP monitoring (OR 1.43; 95 % CI 1.01—3.12). Per our data, invasive ICP monitoring is an independent predictor of infectious complications in the postoperative period (OR 1.39; 95 % CI 1.17—3.19). On day 1 after intracranial hemorrhage, hyperosmotic solutions were used in 35 % of patients who underwent ICP monitoring, and in 19 % of patients without ICP measurement (p &lt; 0.05). Conclusion . ICP monitoring does not decrease postoperative mortality and does not improve outcomes in patients with epidural and subdural hematomas. In these patients, ICP control significantly increases time to death. ICP monitoring significantly decreases postoperative mortality in patients with intracranial hematomas and cerebral contusions. ICP monitoring is effective in patients with consciousness levels of moderate coma and above. ICP control allows to accurately diagnose intracranial hypertension and perform targeted therapy. In the absence of ICP monitoring, hyperosmotic solutions are used empirically or for increased negative neurological symptoms.

Combined Strategy of Burr Hole Surgery and Elective Craniotomy under Intracranial Pressure Monitoring for Severe Acute Subdural Hematoma.

Burr hole surgery in the emergency room can be lifesaving for patients with acute subdural hematoma (ASDH). In the first part of this study, a strategy of combined burr hole surgery, a period of intracranial pressure (ICP) monitoring, and then craniotomy was examined for safe and effective treatment of ASDH. Since 2012, 16 patients with severe ASDH with indications for burr hole surgery were admitted to Kenwakai Otemachi Hospital. From 2012 to 2016, craniotomy was performed immediately after burr hole surgery (emergency [EM] group, n = 10). From 2017, an ICP sensor was placed before burr hole surgery. After a period for correction of traumatic coagulopathy, craniotomy was performed when ICP increased (elective [EL] group, n = 6). Patient background, bleeding tendency, intraoperative blood transfusion, and outcomes were compared between the groups. In the second part of the study, ICP was measured before and after burr hole surgery in seven patients (including two of the six in the EL group) to assess the effect of this surgery. Activated partial thromboplastin time (APTT) and prothrombin time-international normalized ratio (PT-INR) were significantly prolonged after craniotomy in the EM group, but not in the EL group, and the EM group tended to require a higher intraoperative transfusion volume. The rate of good outcomes was significantly higher in the EL group, and ICP was significantly decreased after burr hole surgery. These results suggest the value of burr hole surgery followed by ICP monitoring in patients with severe ASDH. Craniotomy can be performed safely using this method, and this may contribute to improved outcomes.

Invasive Monitoring of Intracranial Pressure After Decompressive Craniectomy in Malignant Stroke.

The role of decompressive hemicraniectomy (DC) in malignant cerebral infarction (MCI) has clearly been established, but little is known about the course of intracranial pressure (ICP) in patients undergoing this surgical measure. In this study, we investigated the role of invasive ICP monitoring in patients after DC for MCI, postulating that postoperative ICP predicts mortality. In this retrospective observational study of MCI patients undergoing DC, ICP were recorded continuously in hourly intervals for the first 72 hours after DC. For every hour, mean ICP was calculated, pooling ICP of every patient. A receiver operating characteristic analysis was performed for hourly mean ICP. A subgroup analysis by age (≥60 years and <60 years) was also performed. A total of 111 patients were analyzed, with 29% mortality rate in patients <60 years, and 41% in patients ≥60 years. A threshold of 10 mm Hg within the first 72 postoperative hours was a reliable predictor of mortality in MCI, with an acceptable sensitivity of 70% and high specificity of 97%. Established predictors of mortality failed to predict mortality. Our study suggests the need to reevaluate postoperative ICP after DC in MCI and calls for a redefinition of ICP thresholds in these patients to indicate further therapy.

Letter to the Editor Regarding “Use of Intracranial Pressure Monitoring in Patients with Severe Traumatic Brain Injury”

Letter to the Editor Regarding “Use of Intracranial Pressure Monitoring in Patients with Severe Traumatic Brain Injury”

Optimizing accuracy of freehand cannulation of the ipsilateral ventricle for intracranial pressure monitoring in patients with brain trauma.

Intracranial pressure (ICP) monitoring in traumatic brain injury (TBI) usually requires the placement of a catheter into the ipsilateral ventricle. This surgical procedure is commonly performed via a freehand method using surface anatomical landmarks as guides. The current accuracy of the catheter placement remains relatively low and even lower among TBI patients. This study was undertaken to optimize the freehand ventricular cannulation to increase the accuracy for TBI. The authors hypothesized that an optimal surgical plan of cannulation should give an operator the greatest degrees of freedom, which could be measured as the range of operation angle, range of catheter placement depth, and size of the target area. An imaging simulation was first performed using the computed tomography (CT) images of 47 adult patients with normal brain anatomy. On the reconstructed 3D head model, four different coronal planes of ventricular cannulation were identified: a 4-cm anterior, a 2-cm anterior, a standard (central), and a 2-cm posterior plane. The degrees of freedom during the cannulation procedure were determined, including the relevant angles, lengths of cannulation, cross-sectional area, and bounding rectangle of the lateral ventricle. Next, a retrospective assessment was performed on the CT scans of another 111 patients with TBI who underwent freehand ventricular cannulation for ICP monitoring. Postoperative measurements were also performed based on CT images to calculate the accuracy and safety of catheter placement between coronal planes in practice. Our simulation results showed that the 2-cm anterior plane had more extensive degrees of freedom for ventricular cannulation, in terms of length of catheter trajectory (7% longer, P<0.001), cross-sectional area of the lateral ventricle (14% larger, P=0.046), and length of the lateral ventricle (17% wider, P<0.001) than that of the standard plane, while both the 4-cm anterior and 2-cm posterior planes did not offer advantages over the standard plane in these ways. The mean length range of catheter trajectory in the 2-cm anterior plane was 41 to 58 mm. Retrospective assessment of TBI patients with ICP monitor placement also confirmed our simulation data. It showed that the accuracy of ipsilateral ventricle cannulation in the 2-cm anterior plane was 70.6%, which was a significant increase from 42.9% in the standard plane (P=0.007). Our imaging simulation and retrospective study demonstrate that different coronal planes could provide different degrees of freedom for cannulation, the 2-cm anterior plane has the greatest degrees of freedom in terms of larger target area and greater length range of the trajectory. The optimized surgical plan in this manner could improve cannulation accuracy and benefit a significant number of TBI patients.