Intracranial Pressure Parameters Research Articles

Preliminary study: Low to moderate PEEP effects on ICP in acute neurological injury patients under mechanical ventilation

Background Acute respiratory distress syndrome (ARDS) significantly impacts mortality and prognosis in acute neurological injury patients. Positive end-expiratory pressure (PEEP) is essential in mechanical ventilation to enhance oxygenation, yet its application may elevate intracranial pressure (ICP). Studies show conflicting findings regarding PEEP's effect on ICP, particularly at low to moderate levels (5–10cmH2O), warranting further investigation in acute neurological injury cases. Objective To assess the impact of low to moderate PEEP on ICP in patients with acute neurological injury who require mechanical ventilation. Methods A retrospective analysis of 62 patients with acute neurological injury requiring mechanical ventilation at our hospital between January 2021 and September 2023 was conducted. Patients were divided into high PEEP (> 10cmH2O) and low to moderate PEEP (5–10cmH2O) groups. Parameters including PaO2, PaCO2, PaO2/FiO2, driving pressure, compliance (Cst), airway resistance, such as heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), central venous pressure (CVP), cardiac index (CI), ICP, and cerebral perfusion pressure (CPP) were recorded pre- and post-ventilation initiation, with correlation analysis performed between ICP and other parameters. Results Pre-treatment comparisons between the high PEEP and low to moderate PEEP groups revealed no significant differences in PaO2, PaCO2, PaO2/FiO2, driving pressure, Cs, and airway resistance. However, post-treatment analysis showed significant disparities, with the high PEEP group exhibiting higher PaO2 and PaO2/FiO2 levels and lower PaCO2, driving pressure, and airway resistance levels compared to the low to moderate PEEP group. Additionally, hemodynamic parameters such as HR, SBP, DBP, CI, MAP, CVP, ICP, and CPP remained more stable in the low to moderate PEEP group post-treatment, with ICP demonstrating significant correlations with various physiological parameters. Conclusion High PEEP improves oxygenation and respiratory mechanics in acute neurological injury patients on mechanical ventilation but may affect hemodynamic parameters, ICP, and CPP. Conversely, low to moderate PEEP has minimal impact on these factors. Hence, personalized adjustment of PEEP levels is essential in clinical management.

Cerebral haemodynamics and intracranial pressure during haemorrhagic shock and resuscitation with total endovascular balloon occlusion of the aorta in an animal model.

To assess changes of cerebral haemodynamic and intracranial pressure (ICP) in animals, with or without elevated ICP, during controlled haemorrhagic shock and resuscitation with Total REBOA (tREBOA). In 22 anaesthetized and normoventilated pigs, after placement of catheters for monitoring invasive proximal blood pressure (pMAP), ICP, and vital parameters, and 60min stabilisation phase, a controlled haemorrhagic shock (HS), was conducted. In 11 pigs (EICPG), an elevated ICP of 25-30 mmHg at the end HS was achieved by simulating an epidural mass. In 11 pigs (NICPG), the ICP was normal. tREBOA was then applied for 120min. The changes of pMAP and ICP were followed, and cerebral perfusion pressure (CPP) calculated. The integrity of the autoregulation was estimated using a calculated Modified-Long Pressure Reactivity Index (mL-PRx). After stabilisation, hemodynamics and physiological parameters were similar and normal in both groups. At the end of the HS, ICP was 16 mmHg in NICPG vs. 32 in EICPG (p = 0.0010). CPP was 30 mmHg in NICPG vs. 6 mmHg in EICPG (p = 0.0254). After aorta occlusion CPP increased immediately in both groups reaching after 15min up to104 mmHg in NICPG vs. 126 mmHg in EICPG. Cerebrovascular reactivity seems to be altered during bleeding and occlusion phases in both groups with positive mL-PRx. The alteration was more pronounced in EICPG, but reversible in both groups. tREBOA is lifesaving by restoration the cerebral circulation defined as CPP in animals with HS with normal or elevated ICP. Despite the observation of short episodes of cerebral autoregulation impairment during the occlusion, mainly in EICPG, tREBOA seems to be an effective tool for improving cerebral perfusion in HS that extends the crucial early window sometimes known as the "golden hour" for resuscitation even after a traumatic brain injury.

Intracranial pressure affects retinal venular complexity in idiopathic intracranial hypertension: a retrospective observational study

BackgroundIncreased intracranial pressure (ICP) in patients with idiopathic intracranial hypertension (IIH) affects the retinal microvasculature, which can be imaged and quantified by optical coherence tomography angiography (OCTA). We aimed to identify the mediating factor between ICP and OCTA parameters association in IIH patients.MethodsIIH patients with active intracranial hypertension were enrolled. OCTA imaging was performed after ICP measurement. We quantified the branching complexity of the retinal arterioles and venules from the superficial vascular complex of the OCTA image. Eyes of IIH patients were stratified into eyes with papilledema (IIH-P) and eyes without papilledema (IIH-WP). All participants underwent visual acuity (VA) examination.ResultsOne hundred and thirty-eight eyes from 70 IIH patients and 146 eyes from 73 controls were included. Compared to the control group, IIH patients and IIH-P had reduced arteriole complexity and increased venule complexity (p < 0.05). For IIH patients and IIH-P, increased retinal venule complexity correlated with increased ICP and reduced VA (p < 0.05); while decreased arteriole complexity only correlated with Frisen scores (p = 0.026). Papilledema mediated the effect (p < 0.001) between ICP and arteriole complexity while ICP had a direct effect (p < 0.001) on venule complexity.ConclusionRetinal venules imaged via OCTA may reflect ICP levels and may underpin the direct effect of increased ICP in IIH patients.

Optic Nerve Head and Retinal Changes in Idiopathic Intracranial Hypertension: Correlation with Short-Term Cerebrospinal Fluid Pressure Monitoring.

We aimed to assess the status of the optic nerve and retina by optical coherence tomography (OCT) in a group of patients with idiopathic intracranial hypertension (IIH) on the basis of dynamic changes in intracranial pressure. This observational and cross-sectional study included patients affected by idiopathic intracranial hypertension with papilledema (IIHWP) and patients with idiopathic intracranial hypertension without papilledema (IIHWOP). All participants underwent an OCT examination of the macula and optic nerve head. Parameters related to intracranial pressure, including cerebrospinal fluid (CSF) opening pressure (oCSFp), CSF mean pressure (mCSFp), and pulse wave amplitude (PWA), were included in the analysis. Out of the 22 subjects enlisted for the study, a total of 16 patients suggestive of IIH were finally enrolled. Papilledema was detected in nine subjects (56.2%) and seven patients were affected by IIHWOP (43.7%). The OCT examination showed a higher mean RNFL thickness in IIHWP patients in comparison to IIHWOP in both eyes (p < 0.05 and p < 0.01, respectively). Intracranial pressure (ICP) measurements showed that IIHWP had higher values of oCSFp, mCSFp, and PWA compared to IIHWOP (p = 0.0001, p = 0.0001, and p = 0.0001, respectively). In addition, ICP parameters significantly correlated with RNFL. Clinical parameters suggestive of idiopathic intracranial hypertension are associated with retina and optic nerve OCT parameters. OCT is a useful tool to detect these alterations in a non-invasive fashion.

Comparison of two minimally invasive surgical approaches for hypertensive intracerebral hemorrhage: a study based on postoperative intracranial pressure parameters

BackgroundIncreased intracranial pressure (ICP) in patients with hypertensive intracerebral hemorrhage (HICH) has been associated with poor prognosis. The transsylvian insular approach (TIA) and the transcortical (TCA) approach are applied for patients with HICH. We aimed to compare the postoperative ICP parameters of TIA and TCA to identify which procedure yields better short-term outcomes in patients with basal ganglia hematoma volumes ranging from 30 to 50 mL.MethodsEighty patients with basal ganglia hematomas 30–50 mL were enrolled in this study. Patients were implanted with ICP probes and divided into TIA and TCA groups according to the procedure. The ICP values were continuously recorded for five days at four-hour intervals. Short-term outcomes were evaluated using the length of hospitalization and postoperative consciousness recovery time.ResultsNo statistically significant differences were found in age, sex, GCS score at admission, hematoma volume, and hematoma clearance rate (p > 0.05). The results showed that postoperative initial ICP, ICP on the first postoperative day, mean ICP, DICP20 mmHg × 4 h, postoperative consciousness recovery time, the length of hospitalization, mannitol utilization rate and the mannitol dosage were lower in the TIA group than in the TCA group (p < 0.05). Postoperative consciousness recovery time was positively correlated with ICP on the first postoperative day, and the length of hospitalization was positively correlated with mean ICP.ConclusionsTIA is more effective than TCA in improving the short-term outcomes of patients with basal ganglia hematoma volumes ranging from 30 to 50 mL according to comparisons of postoperative ICP parameters.

Effects of short-term hyperoxemia on cerebral autoregulation and tissue oxygenation in acute brain injured patients.

Introduction: Potential detrimental effects of hyperoxemia on outcomes have been reported in critically ill patients. Little evidence exists on the effects of hyperoxygenation and hyperoxemia on cerebral physiology. The primary aim of this study is to assess the effect of hyperoxygenation and hyperoxemia on cerebral autoregulation in acute brain injured patients. We further evaluated potential links between hyperoxemia, cerebral oxygenation and intracranial pressure (ICP). Methods: This is a single center, observational, prospective study. Acute brain injured patients [traumatic brain injury (TBI), subarachnoid hemorrhage (SAH), intracranial hemorrhage (ICH)] undergoing multimodal brain monitoring through a software platform (ICM+) were included. Multimodal monitoring consisted of invasive ICP, arterial blood pressure (ABP) and near infrared spectrometry (NIRS). Derived parameters of ICP and ABP monitoring included the pressure reactivity index (PRx) to assess cerebral autoregulation. ICP, PRx, and NIRS-derived parameters (cerebral regional saturation of oxygen, changes in concentration of regional oxy- and deoxy-hemoglobin), were evaluated at baseline and after 10min of hyperoxygenation with a fraction of inspired oxygen (FiO2) of 100% using repeated measures t-test or paired Wilcoxon signed-rank test. Continuous variables are reported as median (interquartile range). Results: Twenty-five patients were included. The median age was 64.7years (45.9-73.2), and 60% were male. Thirteen patients (52%) were admitted for TBI, 7 (28%) for SAH, and 5 (20%) patients for ICH. The median value of systemic oxygenation (partial pressure of oxygen-PaO2) significantly increased after FiO2 test, from 97 (90-101) mm Hg to 197 (189-202) mm Hg, p < 0.0001. After FiO2 test, no changes were observed in PRx values (from 0.21 (0.10-0.43) to 0.22 (0.15-0.36), p = 0.68), nor in ICP values (from 13.42 (9.12-17.34) mm Hg to 13.34 (8.85-17.56) mm Hg, p = 0.90). All NIRS-derived parameters reacted positively to hyperoxygenation as expected. Changes in systemic oxygenation and the arterial component of cerebral oxygenation were significantly correlated (respectively ΔPaO2 and ΔO2Hbi; r = 0.49 (95% CI = 0.17-0.80). Conclusion: Short-term hyperoxygenation does not seem to critically affect cerebral autoregulation.

Alteração da complacência intracraniana em paciente com doença renal crônica e diabetes mellitus T1: um relato de caso

Objective: The aim of this study was to relate the clinical profile with data on blood pressure (BP), intracranial pressure (ICP) and laboratory tests of a patient with Diabetes mellitus (DM) type 1 and chronic kidney disease (CKD) stage 5. Methodology: The research was carried out at the renal replacement therapy outpatient clinic of the Santa Casa de Misericórdia hospital, in Ponta Grossa-PR, previously approved by the ethics committee, under opinion nº 4,039,453. ICP monitoring and BP measurement were performed twice, on follow-up consultation days, in February and September 2020. In addition to the aforementioned parameters, a questionnaire on the patient's habits and demographic data was applied, and a consultation was carried out with the patient medical record for the collection of laboratory test data. Results: From February to September, the volunteer presented with persistent Systemic Arterial Hypertension (SAH) and hyperglycemia, and worsening of laboratory parameters. In February, the ICP morphology showed a significant change, suggesting intracranial hypertension, and the patient had a great impairment of visual acuity. In September, despite the worsening of the health condition, there was a significant improvement in vision and, also, an improvement in the ICP parameters, approaching normality. Between consultations, the diuretic administered by the patient was replaced. Conclusion: it is suggested that the visual impairment is due to intracranial hypertension and the improvement of both is related to the replacement of hydrochlorothiazide by furosemide, which occurred between consultations.

Evaluation of cerebral hemodynamics by transcranial Doppler ultrasonography and its correlation with intracranial pressure in an animal model of intracranial hypertension.

Transcranial Doppler has been tested in the evaluation of cerebral hemodynamics as a non-invasive assessment of intracranial pressure (ICP), but there is controversy in the literature about its actual benefit and usefulness in this situation. To investigate cerebral blood flow assessed by Doppler technique and correlate with the variations of the ICP in the acute phase of intracranial hypertension in an animal model. An experimental animal model of intracranial hypertension was used. The experiment consisted of two groups of animals in which intracranial balloons were implanted and inflated with 4 mL (A) and 7 mL (B) for controlled simulation of different volumes of hematoma. The values of ICP and Doppler parameters (systolic [FVs], diastolic [FVd], and mean [FVm] cerebral blood flow velocities and pulsatility index [PI]) were collected during the entire procedure (before and during hematoma simulations and venous hypertonic saline infusion intervention). Comparisons between Doppler parameters and ICP monitoring were performed. Twenty pigs were studied, 10 in group A and 10 in group B. A significant correlation between PI and ICP was obtained, especially shortly after abrupt elevation of ICP. There was no correlation between ICP and FVs, FVd or FVm separately. There was also no significant change in ICP after intravenous infusion of hypertonic saline solution. These results demonstrate the potential of PI as a parameter for the evaluation of patients with suspected ICP elevation.

Initial intracranial pressure is an independent predictor of unfavorable functional outcomes after aneurysmal subarachnoid hemorrhage

The authors sought to evaluate whether initial intracranial pressure was associated with functional outcomes following aneurysmal subarachnoid hemorrhage. This retrospective analysis consisted of 54 consecutive patients with aneurysmal subarachnoid hemorrhage and acute symptomatic hydrocephalus requiring emergent placement of an external ventricular drain. Patient demographics, clinical data, intracranial pressure parameters, and radiographic imaging were collected. Functional outcomes were evaluated at 3 months using the modified Rankin Scale and dichotomized as favorable (modified Rankin Scale 0–2) or unfavorable (modified Rankin Scale 3–6). Univariate and multivariate logistic regression analyses were performed to investigate parameters independently associated with functional outcomes. In an adjusted multivariate logistic regression model, initial intracranial pressure (OR: 1.371, 95% CI: 1.119–1.679; p = 0.002) was found to be an independent predictor of unfavorable functional outcomes at 3 months. Receiver operating characteristic curve analysis for the prediction of unfavorable functional outcomes demonstrated that initial intracranial pressure exhibited an acceptable area under the curve (AUC = 0.901, 95% CI: 0.818–0.985; p < 0.001). The optimal predictive threshold to distinguish between favorable and unfavorable functional outcomes was identified at an initial intracranial pressure of 25 mmHg.

Use of non-invasive intracranial pressure pulse waveform to monitor patients with End-Stage Renal Disease (ESRD).

End-stage renal disease (ESRD) is treated mainly by hemodialysis, however, hemodialysis is associated with frequent complications, some of them involve the increased intracranial pressure. In this context, monitoring the intracranial pressure of these patients may lead to a better understanding of how intracranial pressure morphology varies with hemodialysis. This study aimed to follow-up patients with ESRD by monitoring intracranial pressure before and after hemodialysis sessions using a noninvasive method. We followed-up 42 patients with ESRD in hemodialysis, for six months. Noninvasive intracranial pressure monitoring data were obtained through analysis of intracranial pressure waveform morphology, this information was uploaded to Brain4care® cloud algorithm for analysis. The cloud automatically sends a report containing intracranial pressure parameters. In total, 4881 data points were collected during the six months of follow-up. The intracranial pressure parameters (time to peak and P2/P1 ratio) were significantly higher in predialysis when compared to postdialysis for the three weekly sessions and throughout the follow-up period (p<0.01) data showed general improvement in brain compliance after the hemodialysis session. Furthermore, intracranial pressure parameters were significantly higher in the first weekly hemodialysis session (p<0.05). In conclusion, there were significant differences between pre and postdialysis intracranial pressure in patients with ESRD on hemodialysis. Additionally, the pattern of the intracranial pressure alterations was consistent over time suggesting that hemodialysis can improve time to peak and P2/P1 ratio which may reflect in brain compliance.

Physiological Responses to In-Bed Cycle Ergometry Treatment in Intensive Care Unit Patients with External Ventricular Drainage.

PurposeEvidence suggests that early physical activity can be accomplished safely in the neurocritical care unit (NCCU); however, many NCCU patients are often maintained in a state of inactivity due to impaired consciousness, sensorimotor deficits, and concerns for intracranial pressure elevation or cerebral hypoperfusion in the setting of autoregulatory failure. Structured in-bed mobility interventions have been proposed to prevent sequelae of complete immobility in such patients, yet the feasibility and safety of these interventions is unknown. We studied neurological and hemodynamic changes before and after cycle ergometry (CE) in a subset of NCCU patients with external ventricular drains (EVDs).MethodsPatients admitted to the NCCU who had an EVD placed for cerebrospinal fluid drainage and intracranial pressure (ICP) monitoring underwent supine CE therapy with passive and active cycling settings. Neurologic status, ICP and hemodynamic parameters were monitored before and after each CE session.ResultsTwenty-seven patients successfully underwent in-bed CE in the NCCU. No clinically significant changes were recorded in neurologic or in physiological parameters before or after CE. There were no device dislodgements or other adverse effects requiring cessation of a CE session.ConclusionThese data suggest that supine CE in a heterogeneous cohort of neurocritical care patients with EVDs is safe and tolerable. Larger prospective studies are needed to determine the efficacy and optimal dose and timing of supine CE in neurocritical care patients.

The role of pulsatile and static intracranial pressure measurements in the management of children with craniosynostosis-an institutional experience from 49 patients.

Although measurement of intracranial pressure (ICP) has occasionally been utilized in children with craniosynostosis (CSS), data on parameters of pulsatile ICP in CSS are still lacking, and the role of pulsatile ICP measurements in the management of CSS is not well established. From our department's database, we retrieved the data from children in whom the measurement of static and pulsatile ICP was a part of the diagnostic work-up in different clinical situations related to CSS. Both clinical and ICP data were retrospectively reviewed and analyzed. We identified 49 children with CSS, median age 4.4years (range 0.2-18.9), in whom a total of 67 diagnostic ICP measurements were undertaken between 2002 and 2014. The CSS was syndromal in 23 cases. The rationale for ICP measurement was a question of indication for cranial vault expansion surgery (CVES) in 12 patients (Group 1), of its timing in 10 patients (Group 2), of suspected abnormally elevated ICP or hydrocephalus in 11 patients (Group 3), of indication for repeated CVES in 13 patients (Group 4), or shunt dysfunction in three patients (Group 5). The average mean ICP for the whole cohort was 15.1 ± 5.5mmHg and mean wave amplitude (MWA) 5.3 ± 2.2mmHg. There was no significant difference in ICP parameters when compared between Groups 1-5. Fundoscopy revealed papilledema in five out of 32 children (15.6%). There were significantly higher parameters of pulsatile ICP (MWA) in patients with papilledema, but no statistically significant difference in parameters of static ICP. In this cohort of pediatric patients with CSS presenting with various diagnostic challenges, we found the diagnostic measurement of static and pulsatile ICP useful in selecting the optimal treatment modality and timing of surgery. Papilledema was associated with elevated pulsatile ICP, a parameter that in previous studies has been shown to correlate with impaired intracranial compliance.

A mathematical model for predicting intracranial pressure based on noninvasively acquired PC-MRI parameters in communicating hydrocephalus.

To develop and validate a mathematical model for predicting intracranial pressure (ICP) noninvasively using phase-contrast cine MRI (PC-MRI). We performed a retrospective analysis of PC-MRI from patients with communicating hydrocephalus (n = 138). The patients were recruited from Shenzhen Second People’s Hospital between November 2017 and April 2020, and randomly allocated into training (n = 97) and independent validation (n = 41) groups. All participants underwent lumbar puncture and PC-MRI in order to evaluate ICP and cerebrospinal fluid (CSF) parameters (i.e., aqueduct diameter and flow velocity), respectively. A novel ICP-predicting model was then developed based on the nonlinear relationships between the CSF parameters, using the Levenberg–Marquardt and general global optimisation methods. There was no significant difference in baseline demographic characteristics between the training and independent validation groups. The accuracy of the model for predicting ICP was 0.899 in the training cohort (n = 97) and 0.861 in the independent validation cohort (n = 41). We obtained an ICP-predicting model that showed excellent performance in the noninvasive diagnosis of clinically significant communicating hydrocephalus.

Detection of intracranial hypertension in children using optical coherence tomography: a systematic review protocol

IntroductionIntracranial hypertension (ICH) in children can have deleterious effects on the brain and vision. It is notoriously difficult to estimate intracranial pressure (ICP) in children and existing methods deliver suboptimal...

Relationship between intracranial pressure and phase-contrast cine MRI-derived measures of cerebrospinal fluid parameters in communicating hydrocephalus

To explore the correlation between intracranial pressure (ICP) and cerebrospinal fluid (CSF) parameters assessed by phase-contrast cine MRI (PC-MRI). Fifteen normal people and 80 subjects with communicating hydrocephalus who underwent PC-MRI examinations from a single center were included in this cross-sectional study. In addition to recording patient's age, heart rate, blood pressure and body mass index (BMI), ICP and CSF hemodynamic parameters, such as flow velocity and aqueduct diameter, were measured for correlation analysis. The mean ICP and CSF aqueduct diameter in hydrocephalus patients were 151.05 mmH2O and 2.877 mm, respectively, and the maximum (6.938 cm/s) and mean (0.845 cm/s) CSF flow velocities were significantly higher in these patients compared with the controls (P<0.05). After adjusting for age, heart rate, blood pressure, and BMI, there was no significant relationship between peak velocity and ICP (P>0.05). Furthermore, a nonlinear relationship was observed between the ICP and the average velocity of CSF, and the ICP and aqueduct diameter. The ICP increased with the average velocity above 1.628 cm/s (P≤0.01), and the aqueduct diameter increased more than 3.6 mm (P<0.001). This study found significant correlations between ICP and average velocity and aqueduct diameter. These findings can be useful in assisting clinicians in predicting ICP more effectively, thus improving patient management.

Airway pressure release ventilation does not increase intracranial pressure in patients with traumatic brain injury with poor lung compliance

The use of Airway Pressure Release Ventilation (APRV) in patients with traumatic brain injury (TBI) remains controversial. Some believe that elevated mean airway pressures transmitted to the thorax may cause clinically significant increases in Central Venous Pressure (CVP) and intracranial pressure (ICP) from venous congestion. We perform a retrospective review from 2009 to 2015 of traumatically injured patients who were transitioned from traditional ventilator modes to APRV and also had an ICP monitor in place. Fifteen patients undergoing 19 transitions to APRV were identified. Prior to transitioning to APRV the average static and dynamic compliance was 22.9 +/− 5.6 and 16.5 +/− 4.12 mL/cm H2O. There was no statistical difference in ICP, MAP, and CPP prior to and after transition to APRV. There was a statistically significant increase in CVP, PaO2, and P:F ratio. Individually, only 4 patients had ICP values >20 in the first hour after transitioning to APRV and the rate of ICP elevations was similar between the two modes of ventilation. These data show that APRV is a viable mode of ventilation in patients with TBI who have low lung compliance. The increased CVP of this mode of ventilation did not affect ICP or hemodynamic parameters.

Transcranial Bioimpedance Measurement as a Non-invasive Estimate of Intracranial Pressure.

We have previously demonstrated a relationship between transcranial bioimpedance (TCB) measurements and intracranial pressure (ICP) in an animal model of raised ICP. The primary objective of this study was to explore the relationship between non-invasive bioelectrical impedance measurements of the brain and skull and ICP in traumatic brain injury (TBI) patients. Included patients were adults admitted to the Neurological Intensive Care Unit with TBI and undergoing invasive ICP monitoring as part of their routine clinical care. Multi-frequency TCB measurements were performed hourly through bi-temporal electrodes. The bioimpedance parameters of Z c (impedance at the characteristic frequency) and R 0 (resistance to a direct current) were then modelled against ICP using unadjusted and adjusted linear models. One hundred and sixty-eight TCB measurements were available from ten study participants. Using an unadjusted linear modelling approach, there was no significant relationship between measured ICP and Zc or R0. The most significant relationship between ICP and TCB parameters was found by adjusting for multiple patient specific variables and using Zc and R0 normalised per patient (p < 0.0001, r 2 = 0.32). These pilot results confirm some degree of relationship between TCB parameters and invasively measured ICP. The magnitude of this relationship is small and, on the basis of the current study, TCB is unlikely to provide a clinically useful estimate of ICP in patients admitted with TBI.

Intracranial Pressure Monitoring as a Part of Multimodal Monitoring Management of Patients with Critical Polytrauma: Correlation between Optimised Intensive Therapy According to Intracranial Pressure Parameters and Clinical Picture.

Trauma patient requires a complex therapeutic management because of multiple severe injuries or secondary complications. The most significant injury found in patients with trauma is head injury, which has the greatest impact on mortality. Intracranial pressure (ICP) monitoring is required in severe traumatic head injury because it optimises treatment based on ICP values and cerebral perfusion pressure (CPP). From a total of 64 patients admitted in the intensive care unit (ICU) 'Casa Austria', from the Polytraumatology Clinic of the Emergency County Hospital "Pius Brinzeu" Timisoara, Romania, between January 2014 and December 2014; only patients who underwent ICP monitoring (n=10) were analysed. The study population was divided into several categories depending on the time passed since trauma to the time of installation of ICP monitoring (<18 h, 19-24 h and >24 h). Comparisons were made in terms of the number of days admitted in the ICU and mortality between patients with head injury who benefited and those who did not benefit from ICP monitoring. The results show the positive influence of ICP monitoring on the number of admission days in ICU because of the possibility that the number of admission days to augment therapeutic effects in patients who benefited from ICP monitoring reduces by 1.93 days compared with those who did not undergo ICP monitoring. ICP monitoring and optimizing therapy according to the ICP and CPP has significant influence on the rate of survival. ICP monitoring is necessary in all patients with head trauma injury according to recent guidelines. The main therapeutic goal in the management of the trauma patient with head injury is to minimize the destructive effects of the associated side effects.

Editorial: Patient-specific intracranial pressure

The accompanying article by Lazaridis et al. describes in detail a study challenging the conventional wisdom of traditional intracranial pressure (ICP) monitoring in the setting of traumatic brain injury (TBI).3 A number of recent studies have failed to show that controlling or reducing ICP below an absolute threshold results in improvement in neurological outcome or mortality rate. Prior reports have challenged the dogma of ICP monitoring as well.1,2 Still, most centers continue to treat posttraumatic brain swelling with control of the absolute ICP to values below 20 or 25 mm Hg, a practice that dates back more than 2 decades, with no supporting Level I evidence. In an age of increased capability for sophisticated monitoring of physiological parameters and neurochemical changes, traditional ICP monitoring continues to play a key role in the management of TBI, despite the mounting evidence questioning its value. Changes in the way we practice require good evidence for an alternative strategy. It is refreshing, therefore, to see a study such as this one in our literature. Rather than proposing the use of additional, expensive, and untested measures, Dr. Lazaridis’ group has proposed an analysis of currently collected physiological parameters that instead takes into account variations in arterial blood pressure to arrive at an index of cerebrovascular reactivity. This approach is rooted in the observation that patients seem to fare better when ICP changes happen slowly and cerebrovascular reactivity remains normal. It has long been observed that patients with chronic increases in ICP (for example, due to slow-growing tumors, pseudotumor, and hydrocephalus) are often minimally symptomatic. The difference between such patients and those with more acute changes in ICP (such as those due to acute epidural hematomas) probably has to do with the lack of cerebrovascular compensation in the latter group. This study attempts to quantify this cerebrovascular reactivity in the setting of TBI, and to examine whether this index has a prognostic significance. This is an elegant study, and appears to provide a way forward in terms of more “personalized” physiological monitoring. Using measures we already collect in our intensive care units, it allows clinicians to derive more meaningful parameters in real time. These parameters do appear to have prognostic value, as these authors show. The more difficult question to ask is whether correcting abnormalities in the derived measures would make a difference in outcome. It is possible that measures such as “ICP dose” and pressure reactivity index (PRx) are mere markers of a bad outcome and cannot be changed with intervention. Only further work looking at how these calculated ICP parameters correlate with other biomarkers and therapeutic interventions will resolve this important issue. The calculated ICP parameters could also help us address why certain patients deteriorate when their abnormally high ICP is reduced too rapidly. It is well known that certain patients with long-standing intracranial hypertension actually get worse when their ICP is normalized. Once again, cerebrovascular reactivity changes are suspected in these situations. Physiological parameters such as ICP dose may help guide therapy in these situations, and prevent neurological sequelae. The authors of this study are helping usher in a new age of physiological monitoring in the neurocritical care unit—one that goes well beyond traditional cardiopulmonary measures and absolute ICPs. Additional studies will further outline the utility, implications, and limitations of these cerebrovascular measures. My only regret is that the software that they have created is available only as a commercial product. Scientific progress and iterative improvements are always more robust when tools such as these are shared with other academic units. (http://thejns.org/doi/abs/10.3171/2013.10.JNS132024)

Domino liver graft with hepatocellular carcinoma used as bridge therapy for a patient with acute liver failure: A case report

We report a unique case of orthotopic domino livertransplantation for a patient with ALF: a noncirrhoticliver graft with HCC was used as bridge therapy untila permanent deceased donor graft became available.A 42-year-old Hispanic woman presenting with ALFwas admitted to the emergency department and waspromptly listed for emergency liver transplantation.However, her clinical deterioration progressed rapidly,the patient required mechanical ventilatory support,and an epidural intracranial pressure monitor wasplaced. The patient developed intracranial hyperten-sion (25-30 mm Hg), which was successfully con-trolled with medical therapy. Synchronously,scheduled living donor liver transplantation (LDLT)was being performed for a 60-year-old female patientwith a history of recurrent HCC in a noncirrhotic liver.This patient had previously undergone a series of sur-gical and ablative treatments. The actual tumor bur-den was 2 HCC lesions (each 20 mm in diameter), theserum alpha-fetoprotein level was 2.4 ng/mL, and novascular or extrahepatic metastasis was found at thetime of LDLT.Progressive worsening of an already critical clinicalcondition in the first patient, the absence of either adeceased donor or a living donor after 5 days on thewaiting list, and no access to liver support systems orbioartificial devices at that time led the transplantteam to consider a domino liver transplant using theexplanted noncirrhotic liver with HCC from the secondpatient undergoing synchronous LDLT as bridge ther-apy. Consent was obtained from both the recipientand donor families, the institutional ethics committee,and the Instituto Nacional Central Unico Coordinadorde Ablacion e Implante. A sequential triple-procedureschedule was followed: left lobe LDLT; back-tableresection of the two 2-cm HCC lesions in segments VIand IV; and, finally, domino implantation of the HCCliver graft with the piggyback technique. The coldischemia time lasted 4 hours, and the warm ischemiatime was 40 minutes. Shortly after transplantation,vasopressor infusion was discontinued, and the intra-cranial pressure parameters improved to 15 to 17 mmHg (Fig. 1). Twelve hours after the domino procedure,a deceased donor graft from a 49-year-old female,located 600 km from the hospital, was made availablefor this patient. The deceased donor liver transplanta-tion procedure began 11 hours after the completion ofthe bridge domino liver transplant with the resectedHCC graft, and it lasted a total of 165 minutes with acold ischemia time of 6 hours.A pathological examination of the explanted dominoHCC liver graft confirmed 2 small HCC nodules: one