Intracranial Pressure Scores Research Articles

Intracranial pulse pressure amplitude as an indicator of intracranial compliance: observations in symptomatic children with Chiari malformation type I.

Reduced intracranial compliance (ICC) may be an important factor in the pathophysiology of Chiari malformation type I (CM-I). However, direct measurement of ICC is controversial because of its invasiveness, particularly in children. Instead, ICC may be estimated from continuous measurements of intracranial pressure (ICP), where the metric mean wave amplitude (MWA) has been found to be more useful as a surrogate marker of ICC than mean ICP. This observational study investigated the distribution of MWA and mean ICP in symptomatic children with CM-I, as well as their association with clinical and radiological findings. From a consecutive series of children treated for CM-I at a single institution between 2006 and 2023, the authors analyzed ICP scores in those who underwent an overnight preoperative ICP recording in which MWA was calculated. Clinical and radiological data were retrieved from the patient records. Thirty-seven children (mean age 12.4 ± 3.6 years) with symptomatic CM-I were identified. From the overnight ICP measurements, the average MWA was 5.2 ± 1.3 mm Hg: 56% of children had an abnormal MWA (> 5 mm Hg) and 33% had a borderline MWA (4-5 mm Hg). In contrast, the average mean ICP was 9.7 ± 4.1 mm Hg: 8% of children had an abnormal mean ICP (> 15 mm Hg) and 41% had a borderline mean ICP (10-15 mm Hg). Thus, more children were found to have an abnormal MWA than an abnormal mean ICP (p < 0.001). MWA was significantly higher in the subgroup of children with medullary compression in the foramen magnum, as seen on MRI, than in those without (5.6 ± 1.0 mm Hg vs 4.7 ± 1.4 mm Hg, p = 0.03), whereas a similar difference was not observed for mean ICP (9.9 ± 4.6 mm Hg vs 9.7 ± 3.7 mm Hg, p = 0.889). In this cohort of symptomatic children with CM-I, MWA was more frequently abnormal than mean ICP, with a clinically significant discrepancy in half of the patients. Moreover, MWA was significantly higher in patients with medullary compression. Based on these findings, the authors' interpretation is that in children with CM-I, the ICC may be reduced, as indicated by increased MWA, even though the mean ICP is within normal thresholds.

Predicting neurosurgical clearance in the polytrauma patient with concomitant traumatic brain injury

The goal of this study is to develop a model based on previously used prognostic predictors in traumatic brain injury (TBI) patients with polytrauma, which will facilitate the decision-making of whether to clear these patients for non-cranial surgery. Data of eligible patients was obtained from a trauma database at a Level I trauma and academic tertiary referral center in the United States. The number of days seen by the neurosurgical service prior to clearance, injury severity score (ISS), post-trauma day 0 (PTD 0) of Glasgow Coma Score (GCS), intracranial pressure (ICP) score and computed tomography (CT) score, as well as the changes in GCS, ICP score and CT score between PTD 0 and day of clearance were the variables used in developing the model. The Neurosurgical Clearance Model (NCM) was developed using data from 50 patients included in the study. Patients were cleared by neurosurgeons 1.6 days later than it would appear possible based on a retrospective review of the patients’ clinical conditions. A single model equation was developed, the ultimate result of which is a clearance probability value. The best cutoff clearance probability value was found to be 0.584 (or 58.4%) using Receiver Operator Characteristic curve analysis. Our data suggests that neurosurgeons are risk-averse in clearing polytrauma patients for non-cranial surgery. This pilot NCM, if reproduced and validated by other groups and in larger prospective studies, may become a useful tool to assist clinicians in this often-difficult decision-making process.

Magnetic resonance imaging biomarkers of cerebrospinal fluid tracer dynamics in idiopathic normal pressure hydrocephalus.

Disturbed clearance of toxic metabolites from the brain via cerebrospinal fluid is emerging as an important mechanism behind dementia and neurodegeneration. To this end, magnetic resonance imaging work-up of dementia diseases is largely focused on anatomical derangements of the brain. This study explores magnetic resonance imaging biomarkers of cerebrospinal fluid tracer dynamics in patients with the dementia subtype idiopathic normal pressure hydrocephalus and a cohort of reference subjects. All study participants underwent multi-phase magnetic resonance imaging up to 48 h after intrathecal administration of the contrast agent gadobutrol (0.5 ml, 1 mmol/ml), serving as cerebrospinal fluid tracer. Imaging biomarkers of cerebrospinal fluid tracer dynamics (i.e. ventricular reflux grades 0–4 and clearance) were compared with anatomical magnetic resonance imaging biomarkers of cerebrospinal fluid space anatomy (Evans’ index, callosal angle and disproportional enlargement of subarachnoid spaces hydrocephalus) and neurodegeneration (Schelten’s medial temporal atrophy scores, Fazeka’s scores and entorhinal cortex thickness). The imaging scores were also related to a pulsatile intracranial pressure score indicative of intracranial compliance. In shunt-responsive idiopathic normal pressure hydrocephalus, the imaging biomarkers demonstrated significantly altered cerebrospinal fluid tracer dynamics (ventricular reflux grades 3–4 and reduced clearance of tracer), deranged cerebrospinal fluid space anatomy and pronounced neurodegeneration. The altered MRI biomarkers were accompanied by pressure indices of impaired intracranial compliance. In conclusion, we present novel magnetic resonance imaging biomarkers characterizing idiopathic normal pressure hydrocephalus pathophysiology, namely measures of cerebrospinal fluid molecular redistribution and clearance, which add information to traditional imaging scores of cerebrospinal fluid space anatomy and neurodegeneration.

CT-Based Classification of Acute Cerebral Edema: Association with Intracranial Pressure and Outcome.

Brain edema after acute cerebral lesions may lead to raised intracranial pressure (ICP) and worsen outcome. Notwithstanding, no CT-based scoring system to quantify edema formation exists. This retrospective correlative analysis aimed to establish a valid and definite CT score quantifying brain edema after common acute cerebral lesions. A total of 169 CT investigations in 60 patients were analyzed: traumatic brain injury (TBI; n = 47), subarachnoid hemorrhage (SAH; n = 70), intracerebral hemorrhage (ICH; n = 42), and ischemic stroke (n = 10). Edema formation was classified as 0: no edema, 1: focal edema confined to 1 lobe, 2: unilateral edema > 1 lobe, 3: bilateral edema, 4: global edema with disappearance of sulcal relief, and 5: global edema with basal cisterns effacement. ICP and Glasgow Outcome Score (GOS) were correlated to edema formation. Median ICP values were 12.0, 14.0, 14.9, 18.2, and 25.9 mmHg in grades 1-5, respectively. Edema grading significantly correlated with ICP (r = .51; P<.0001) in focal and global cerebral edema, particularly in patients with TBI, SAH, and ICH (r = .5, P<.001; r = .5; P<.0001; r = .6, P<.0001, respectively). At discharge, 23.7% of patients achieved a GOS of 5 or 4, 65.0% reached a GOS of 3 or 2, and 11.9% died (GOS 1). CT-score of cerebral edema in all patients correlated with outcome (r = -.3, P = .046). The proposed CT-based grading of extent of cerebral edema significantly correlated with ICP and outcome in TBI, SAH, and ICH patients and might be helpful for standardized description of CT-images and as parameter for clinical studies, for example, measuring effects of antiedematous therapies.

Effect of Bone Flap Surface Area on Outcomes in Decompressive Hemicraniectomy for Traumatic Brain Injury

Decompressive hemicraniectomy to control medically refractory intracranial hypertension and cerebral edema and evacuate mass lesions in traumatic brain injury is a widely accepted treatment paradigm. However, the critical specifications of the bone flap size necessary to control the intracranial pressure (ICP) and provide improved patient outcomes is unknown. We assessed the effect of craniectomy size on the outcomes in surgical decompression for traumatic brain injury. From 2003 to 2011, 58 cases of decompressive hemicraniectomy were performed for evacuation of hematoma and treatment of refractory ICP in adult patients with traumatic brain injury. The surface area of the decompressive bone flaps was calculated from the postoperative computed tomography scans and correlated with the ICP and Glasgow Coma Scale scores immediately postoperatively and during long-term follow-up. Decompressive craniectomy led to a statistically significant continued reduction in the preoperative ICP values (24.5 mm Hg; range, 5-30 mm Hg) compared with the postoperative ICP (16.7 mm Hg; range, 1-30; P= 0.006). However, no significant improvement in the preoperative Glasgow Coma Scale (7.47 mm Hg; range, 3-15; vs. 7.50 mm Hg; range, 3-15; P= 0.96) was observed with hemicraniectomy. For surface areas of 7000-16,000 mm2, size was an independent factor in ICP reduction but not for the overall neurologic outcome.

Brain Capillary Ultrastructure in Idiopathic Normal Pressure Hydrocephalus: Relationship With Static and Pulsatile Intracranial Pressure.

Idiopathic normal pressure hydrocephalus (iNPH) is a neurodegenerative disease of unknown cause. We investigated the morphology of capillaries in frontal cortex biopsies from iNPH patients and related the observations to overnight intracranial pressure (ICP) scores. A biopsy (0.9×10 mm) was taken from where the ICP sensor subsequently was inserted. Brain capillaries were investigated by electron microscopy of biopsies from 27 iNPH patients and 10 reference subjects, i.e. patients (not healthy individuals) without cerebrospinal fluid circulation disturbances, in whom normal brain tissue was removed as part of necessary neurosurgical treatment. Degenerating and degenerated pericyte processes were identified in 23/27 (85%) iNPH and 6/10 (60%) of reference specimens. Extensive disintegration of pericyte processes were recognized in 11/27 (41%) iNPH and 1/10 (10%) reference specimens. There were no differences in basement membrane (BM) thickness or pericyte coverage between iNPH and reference subjects. The pulsatile or static ICP scores did neither correlate with the BM thickness nor with pericyte coverage. We found increased prevalence of degenerating pericytes in iNPH while the BM thickness and pericyte coverage did not differ from the reference individuals. Observations in iNPH may to some extent be age-related since the iNPH patients were significantly older than the reference individuals.

The association between the pulse pressure gradient at the cranio-cervical junction derived from phase-contrast magnetic resonance imaging and invasively measured pulsatile intracranial pressure in symptomatic patients with Chiari malformation type 1.

In symptomatic Chiari malformation type 1 (CMI), impaired intracranial compliance (ICC) is associated with an increased cranio-spinal pulsatile pressure gradient. Phase-contrast magnetic resonance imaging (MRI) represents a non-invasive modality for the assessment of the pulse pressure gradient at the cranio-cervical junction (CCJ). We wished to explore how the MRI-derived pulse pressure gradient (MRI-dP) compares with invasively measured pulsatile intracranial pressure (ICP) in CMI, and with healthy controls. From phase-contrast MRI of CMI patients and healthy controls, we computed cerebrospinal fluid (CSF) flow velocities and MRI-dP at the CCJ. We assessed bidirectional flow and compared the flow between the anterior and the posterior subarachnoid space at the CCJ. We computed total intracranial volume (ICV), ventricular CSF volume (VV), and posterior cranial fossa volume (PCFV). We analyzed the static and pulsatile ICP scores from overnight monitoring in CMI patients. Five CMI patients and four healthy subjects were included. The CMI group had a significantly larger extent of tonsillar ectopia, smaller PCFV, and a smaller area of CSF in the FM. The pulsatile ICP (mean ICP wave amplitude, MWA) was abnormally increased in 4/5 CMI patients and correlated positively with MRI-dP. However, the MRI-dP as well as the CSF flow velocities did not differ significantly between CMI and healthy subjects. Moreover, bidirectional flow was observed in both CMI as well as healthy subjects, with no significant difference. In symptomatic CMI patients, we found a significant association between the pulse pressure gradient at the CCJ derived from phase-contrast MRI and the pulsatile ICP (MWA) measured invasively. However, the MRI-dP was close to identical in CMI patients and healthy subjects. Moreover, the CSF flow velocities at the CCJ and the occurrence of bidirectional flow were not different in CMI patients and healthy individuals. Further studies are required to determine the diagnostic role of phase-contrast MRI in CMI patients.

Comparative observational study on the clinical presentation, intracranial volume measurements, and intracranial pressure scores in patients with either Chiari malformation Type I or idiopathic intracranial hypertension.

OBJECTIVE Several lines of evidence suggest common pathophysiological mechanisms in Chiari malformation Type I (CMI) and idiopathic intracranial hypertension (IIH). It has been hypothesized that tonsillar ectopy, a typical finding in CMI, is the result of elevated intracranial pressure (ICP) combined with a developmentally small posterior cranial fossa (PCF). To explore this hypothesis, the authors specifically investigated whether ICP is comparable in CMI and IIH and whether intracranial volumes (ICVs) are different in patients with CMI and IIH, which could explain the tonsillar ectopy in CMI. The authors also examined whether the symptom profile is comparable in these 2 patient groups. METHODS The authors identified all CMI and IIH patients who had undergone overnight diagnostic ICP monitoring during the period from 2002 to 2014 and reviewed their clinical records and radiological examinations. Ventricular CSF volume (VV), PCF volume (PCFV), and total ICV were calculated from initial MRI studies by using volumetric software. The static and pulsatile ICP scores during overnight monitoring were analyzed. Furthermore, the authors included a reference (REF) group consisting of patients who had undergone ICP monitoring due to suspected idiopathic normal-pressure hydrocephalus or chronic daily headache and showed normal pressure values. RESULTS Sixty-six patients with CMI and 41 with IIH were identified, with comparable demographics noted in both groups. The occurrence of some symptoms (headache, nausea, and/or vomiting) was comparable between the cohorts. Dizziness and gait ataxia were significantly more common in patients with CMI, whereas visual symptoms, diplopia, and tinnitus were significantly more frequent in patients with IIH. The cranial volume measurements (VV, PCFV, and ICV) of the CMI and IIH patients were similar. Notably, 7.3% of the IIH patients had tonsillar descent qualifying for diagnosis of CMI (that is, > 5 mm). The extent of tonsillar ectopy was significantly different between the CMI and IIH cohorts (p < 0.001) but also between these 2 cohorts and the REF group. Pulsatile ICP was elevated in both cohorts without any significant between-group differences; however, static ICP was significantly higher (p < 0.001) in the IIH group. CONCLUSIONS This study showed comparable and elevated pulsatile ICP, indicative of impaired intracranial compliance, in both CMI and IIH cohorts, while static ICP was higher in the IIH cohort. The data did not support the hypothesis that reduced PCFV combined with increased ICP causes tonsillar ectopy in CMI. Even though impaired intracranial compliance seems to be a common pathophysiological mechanism behind both conditions, the mechanisms explaining the different clinical and radiological presentations of CMI and IIH remain undefined.

The correlation between pulsatile intracranial pressure and indices of intracranial pressure-volume reserve capacity: results from ventricular infusion testing.

OBJECTIVE The objective of this study was to examine how pulsatile and static intracranial pressure (ICP) scores correlate with indices of intracranial pressure-volume reserve capacity, i.e., intracranial elastance (ICE) and intracranial compliance (ICC), as determined during ventricular infusion testing. METHODS All patients undergoing ventricular infusion testing and overnight ICP monitoring during the 6-year period from 2007 to 2012 were included in the study. Clinical data were retrieved from a quality registry, and the ventricular infusion pressure data and ICP scores were retrieved from a pressure database. The ICE and ICC (= 1/ICE) were computed during the infusion phase of the infusion test. RESULTS During the period from 2007 to 2012, 82 patients with possible treatment-dependent hydrocephalus underwent ventricular infusion testing within the department of neurosurgery. The infusion tests revealed a highly significant positive correlation between ICE and the pulsatile ICP scores mean wave amplitude (MWA) and rise-time coefficient (RTC), and the static ICP score mean ICP. The ICE was negatively associated with linear measures of ventricular size. The overnight ICP recordings revealed significantly increased MWA (> 4 mm Hg) and RTC (> 20 mm Hg/sec) values in patients with impaired ICC (< 0.5 ml/mm Hg). CONCLUSIONS In this study cohort, there was a significant positive correlation between pulsatile ICP and ICE measured during ventricular infusion testing. In patients with impaired ICC during infusion testing (ICC < 0.5 ml/mm Hg), overnight ICP recordings showed increased pulsatile ICP (MWA > 4 mm Hg, RTC > 20 mm Hg/sec), but not increased mean ICP (< 10-15 mm Hg). The present data support the assumption that pulsatile ICP (MWA and RTC) may serve as substitute markers of pressure-volume reserve capacity, i.e., ICE and ICC.

Perioperative monitoring of pulsatile and static intracranial pressure in patients with Chiari malformation type 1 undergoing foramen magnum decompression.

Patients with Chiari malformation type 1 (CMI) often present with elevated pulsatile and static intracranial pressure (ICP). The preferred treatment of CMI, foramen magnum decompression (FMD), is assumed to normalise ICP and craniospinal pressure dissociation. In order to further explore the mechanisms behind FMD, the present study investigated whether or not pulsatile and static ICP normalises immediately after FMD. The study included CMI patients undergoing FMD with perioperative ICP monitoring as a part of clinical management. The pulsatile and static ICP scores were retrieved from the department's ICP database, and the clinical and radiological data from the patient records. Eleven patients were included in the study. During the first 3 days following FMD, mixed model analysis revealed no significant time-dependent differences of preoperatively elevated either pulsatile (mean wave amplitude, MWA; p = 0.85) and/or static (mean ICP, p = 0.90) ICP. Percentage of mean ICP >15 mmHg increased during days 2 and 3 after FMD. Two patients from the present series had to receive ventriculoperitoneal shunt after FMD in the early postoperative period. The present observations suggest that anatomical restoration of cerebrospinal fluid pathways by FMD does not lead to immediate normalisation of preoperatively altered pulsatile and static ICP in patients with CMI. This finding may explain persistent symptoms during the early period after FMD.

Outcome of Surgery for Idiopathic Normal Pressure Hydrocephalus: Role of Preoperative Static and Pulsatile Intracranial Pressure

To examine the outcome of surgery for idiopathic normal-pressure hydrocephalus (iNPH) and how outcome relates to the preoperative static and pulsatile intracranial pressure (ICP). An observational cohort study included all patients with iNPH managed at our department during the years 2002-2012 in whom overnight ICP monitoring was part of the preoperative work-up. Clinical data were retrieved from a quality registry and ICP scores from a pressure database. The study included 472 patients, 316 in the surgery group and 156 in the nonsurgery group. Among those treated surgically, 278 (90%) showed clinical improvement (Responders) whereas 32 (10%) had no improvement (Nonresponders). Among Responders, only about one third reached the best clinical scores; moreover, the difference in clinical score between Responders and Nonresponders declined with time after surgery, particularly after 3-4 years. The surgery was accompanied by acute intracranial hematomas in 11 patients (3.5%), of whom 4 (1.3%) died. Survival (age at death) was significantly greater among the Responders than in Nonresponders. Although the static ICP was normal in all patients, the pulsatile ICP was significantly greater in Responders than in Non-responders. The pulsatile ICP was greater in shunt Responders than Nonresponders. Although the clinical improvement declined over time and the majority did not experience complete relief of symptoms, shunt Responders lived significantly longer than Nonresponders. The present observations suggest that the current surgical treatment regimens for iNPH (primarily shunt surgery) address only some aspects of the disease process, in particular the aspect of brain water disturbance.

Aqueductal Stroke Volume: Comparisons with Intracranial Pressure Scores in Idiopathic Normal Pressure Hydrocephalus.

Aqueductal stroke volume from phase-contrast MR imaging has been proposed for predicting shunt response in normal pressure hydrocephalus. However, this biomarker has remained controversial in use and has a lack of validation with invasive intracranial monitoring. We studied how aqueductal stroke volume compares with intracranial pressure scores in the presurgical work-up and clinical score, ventricular volume, and aqueduct area and assessed the patient's response to shunting. Phase-contrast MR imaging was performed in 21 patients with probable idiopathic normal pressure hydrocephalus. Patients were selected for shunting on the basis of pathologically increased intracranial pressure pulsatility. Patients with shunts were offered a second MR imaging after 12 months. Ventricular volume and transverse aqueductal area were calculated, as well as clinical symptom score. No correlations between aqueductal stroke volume and preoperative scores of mean intracranial pressure or mean wave amplitudes were observed. Preoperative aqueductal stroke volume was not different between patients with shunts and conservatively treated patients (P = .69) but was correlated with ventricular volume (R = 0.60, P = .004) and aqueductal area (R = 0.58, P = .006) but not with the severity or duration of clinical symptoms. After shunting, aqueductal stroke volume (P = .006) and ventricular volume (P = .002) were reduced. A clinical improvement was seen in 16 of 17 patients who had shunts (94%). Aqueductal stroke volume does not reflect intracranial pressure pulsatility or symptom score, but rather aqueduct area and ventricular volume. The results do not support the use of aqueductal stroke volume for selecting patients for shunting.

Association between ventricular volume measures and pulsatile and static intracranial pressure scores in non-communicating hydrocephalus

BackgroundIn non-communicating hydrocephalus (HC), enlarged cerebral ventricles are often thought to reflect increased intracranial pressure (ICP) or increased pulsatile ICP. The present study was undertaken to explore the association between ventricular volume measures and pulsatile or static ICP scores in patients with non-communicating HC. Since linear measures of ventricular size have the most widespread use, we also examined how linear and volume measures of ventricular size compare. MethodsThe patient material includes all patients with non-communicating HC that underwent continuous over-night ICP monitoring during the period 2002–2011. The scores of pulsatile and static ICP were determined from the continuous ICP signals stored on the hospital server. Ventricular volume was determined both as linear measures of sectional CT or MR images and as 3D volume of all ventricles. We also determined the ventricular volume index as a relationship between ventricular volume and intracranial volume. ResultsEighty-five patients were included in the study; they were dichotomized into those that previously had not received endoscopic third ventriculostomy (ETV; n=52; Group 1), and those that had previously underwent ETV (n=33; Group 2). None was previously shunted. We found no significant correlations between the ICP scores and the ventricular volume indices in neither of the patient groups. In Group 1, however, the mean ICP wave amplitude was significantly higher than in Group 2. There was a strong positive correlation between volume and linear measures of ventricular size. We found neither any association between age and ventricular volume; nor any association between ventricular volume and duration of symptoms. ConclusionsIn this cohort of patients with non-communicating HC, we found no evidence of a proportional correlation between ventricular volume and pulsatile or static ICP. However, the findings suggest that symptomatic and untreated non-communication HC is still associated with reduced intracranial compliance.

ABSTRACT 352

Background and aims: Role of various osmotherapy agents in treating children with raised intracranial pressure (ICP) due to acute central nervous system (CNS) infections is not well studied. Aims: Compare the 20%-Mannitol versus 3%-Hypertonic saline (HTS) in children with raised ICP due to acute CNS infections. Design: Prospective open label RCT in level-III PICU. Subjects: Children, aged 1–12 years with raised ICP and modified-GCS Score ≤8. Interventions: ICP was monitored using intraparenchymal microtransducer (Codman®). ICP above 20 mmHg was treated either with 20%-Mannitol, 0.5 gram/kg/dose over 20-min as and when required (Mannitol-Group, n=28) or 3%-HST, 10 ml/kg loading then 0.5–1 ml/kg/hr at sliding scale infusion (HTS-Group, n=29). Serum osmolarity of 330 mOsmol, sodium of 160 mEq/l were accepted. Outcomes: Primary: Efficacy of mannitol and HTS to bring ICP < 20 mmHg. Secondary: m-GCS score at 72-hrs and poor outcomes (death plus severe sequelae) at 3 months. Study registered with ctri.nic.in (CTRI/2011/09/001997). Results: Significant reduction in mean ICP (14 vs. 22 mmHg, p=0.010) with a corresponding increase in CPP (67 vs. 53 mmHg; p=0.001) was noted during 72-hrs in HTS-group as compared to Mannitol-group. HTS successfully controlled raised ICP in 79% of patients, in contrast to 50% by mannitol (RR=0.63, 95% CI 0.42–0.95; p=0.020). Median (IQR) m-GCS score was higher in HTS-group as compared to Mannitol-group (10 (7–11) vs. 7 (3–9); p=0.003). HTS-group had a lower poor outcome than Mannitol-group (34.5% vs. 68%) (RR=0.49, 95% CI 0.27 - 0.89; p=0.012). Conclusions: 3%-Saline was superior to 20%-Mannitol for controlling raised ICP in acute CNS infections.

Baseline pressure errors (BPEs) extensively influence intracranial pressure scores: results of a prospective observational study

BackgroundMonitoring of intracranial pressure (ICP) is a cornerstone in the surveillance of neurosurgical patients. The ICP is measured against a baseline pressure (i.e. zero - or reference pressure). We have previously reported that baseline pressure errors (BPEs), manifested as spontaneous shift or drifts in baseline pressure, cause erroneous readings of mean ICP in individual patients. The objective of this study was to monitor the frequency and severity of BPEs. To this end, we performed a prospective, observational study monitoring the ICP from two separate ICP sensors (Sensors 1 and 2) placed in close proximity in the brain. We characterized BPEs as differences in mean ICP despite near to identical ICP waveform in Sensors 1 and 2.MethodsThe study enrolled patients with aneurysmal subarachnoid hemorrhage in need of continuous ICP monitoring as part of their intensive care management. The two sensors were placed close to each other in the brain parenchyma via the same burr hole. The monitoring was performed as long as needed from a clinical perspective and the ICP recordings were stored digitally for analysis. For every patient the mean ICP as well as the various ICP wave parameters of the two sensors were compared.ResultsSixteen patients were monitored median 164 hours (ranges 70 – 364 hours). Major BPEs, as defined by marked differences in mean ICP despite similar ICP waveform, were seen in 9 of them (56%). The BPEs were of magnitudes that had the potential to alter patient management.ConclusionsBaseline Pressure Errors (BPEs) occur in a significant number of patients undergoing continuous ICP monitoring and they may alter patient management. The current practice of measuring ICP against a baseline pressure does not comply with the concept of State of the Art. Monitoring of the ICP waves ought to become the new State of the Art as they are not influenced by BPEs.

Effect of Tianhuang Granule (田黄冲剂) on intracranial pressure and serum matrix metalloproteinase-9 in patients with acute cerebral hemorrhage

To study the effect and mechanism of Tianhuang Granule (, THG) on: hydrocephalus in the patients with acute cerebral hemorrhage (ACH) through intracranial pressure (ICP) monitoring, serum matrix metalloproteinase-9 (MMP-9) level observation, and National Institutes of Health Stroke Scale (NIHSS) scoring (for nerve function de ficit). Sixty patients with ACH were equally randomized: into two groups by lottery, the control group and the THG group; all were treated with conventional therapy, but to the patients in the THG group, THG was given orally in addition for 28 days. Changes of ICP, MMP-9 expression, and NIHSS scores, as well as the degree of cerebral hematoma and hydrocephalus (by cranial CT scanning) in the patients, were estimated and compared. (1) ICP was lowered more significantly in the: THG group, showing a significant difference between groups on day 7 (P<0.05). (2) MMP-9 expression was down-regulated in the THG group more significantly and earlier than that in the control group. (3) The degrees of cerebral hematoma and hydrocephalus in the THG group on day 7 were reduced significantly as compared with those on day 3 (P<0.05), but in the control group, the day of significant reduction was delayed to day 14, and the degrees on day 7 and day 14 in the two groups were significantly different (P<0.05 and P<0.01). (4) NIHSS score was significantly lower in the THG group than that in the control group on day 14 and day 28 (P<0.05 and P<0.01). THG can effectively lower ICP, down-regulate MMP-9 expression, promote the absorption: of cerebral hematoma and hydrocephalus, and improve the nerve function, showing a clinical effectiveness than conventional therapy.

Effect of sex steroid hormones on brain edema, intracranial pressure, and neurologic outcomes after traumatic brain injury

Recent studies have reported that estrogen and progesterone have a neuroprotective effect after traumatic brain injury (TBI); however, the mechanism(s) for this effect have not yet been elucidated. The aim of the present study was to investigate the role of sex steroid hormones on changes in brain edema, intracranial pressure (ICP), and cerebral perfusion pressure (CPP) after TBI in ovariectomized (OVX) rats. In this study, 50 female rats were divided into 5 groups: control (intact), sham, and 3 TBI groups consisting of vehicle, estrogen (1 mg/kg), and progesterone (8 mg/kg). TBI was induced by the Marmarou method, and the hormones were injected i.p. 30 min after TBI. ICP was measured in the spinal cord, and CPP was calculated by subtracting the mean arterial pressure (MAP) from ICP. The results revealed that brain water content after TBI was lower (p < 0.001) in the estrogen and progesterone groups than in the vehicle group. After trauma, ICP was significantly higher in TBI rats (p < 0.001). The ICP in the estrogen and progesterone groups decreased at 4 and 24 h after TBI compared with vehicle (p < 0.001 and p < 0.05, respectively). The CPP in the estrogen and progesterone groups increased after 24 h compared with vehicle (p < 0.001). Also after TBI, the neurological score (veterinary coma scale) was significantly higher than vehicle at 1 h (p < 0.01) and 24 h (p < 0.001) in the group treated with estrogen. In conclusion, pharmacological doses of estrogen and progesterone improved ICP, CPP, and neurological scores after TBI in OVX rats, which implies that these hormones play a neuroprotective role in TBI.

Percutaneous Tracheostomy in Neurosurgical Patients With Intracranial Pressure Monitoring Is Safe

Percutaneous tracheostomy (PT) is performed routinely on neurosurgical patients in many critical care units. Some of these patients suffer from severe brain injury and require intracranial pressure (ICP) monitoring. It remains uncertain whether this procedure causes an increase in ICP or jeopardizes the cerebral perfusion pressure (CPP) in these patients. We studied the effects of PT on ICP and CPP in this group of patients. Our study group consisted of 52 neurosurgical patients in the surgical intensive care unit of an urban, Level I Trauma Center who had ICP monitoring and underwent PT between 2001 and 2005. Data were collected from 24 hours before to 24 hours after PT. ICP, CPP, and Glasgow Coma Score (GCS) scale were measured hourly during the study period. There was no statistically significant change in the mean ICP over the 48-hour study period or after the procedure. There was a temporary increase in ICP during the procedure (1.60 mm Hg) which was statistically not significant. There was statistically significant increase in the mean CPP after the procedure, although this increase was clinically not significant. The risk of having a critically high ICP (>20 mm Hg) or low CPP (<60 mm Hg) values did not increase after the procedure. There was no significant change in GCS after the procedure. PT in neurosurgical patients with ICP monitor does not cause clinically significant or hazardous changes in ICP, CPP, and GCS. We therefore consider PT to be safe in neurosurgical patients.