Decrease In Intracranial Pressure Research Articles

Effect of Prone Position Ventilation in Patients with Severe Craniocerebral Injury Complicated with Pulmonary Infection

Objective: To investigate the effects of prone ventilation in patients with severe traumatic brain injury combined with pulmonary infection. Methods: A total of 100 patients with severe traumatic brain injury combined with pulmonary infection in the hospital were randomly divided into a prone ventilation group and a conventional ventilation group, with 50 patients in each group. The Glasgow Coma Scale (GCS) score, APACHE II score, sputum culture results, oxygenation indicators, and prognosis were compared between the two groups. Data were processed using SPSS 25.0 statistical software, and t-tests and chi-square tests were used to compare continuous and categorical variables, respectively. Results: The experimental group showed better oxygenation indicators, a lower positive rate of sputum cultures, and reduced intracranial pressure compared to the control group (all P < 0.05). Multivariate Cox regression analysis indicated that GCS score, APACHE II score, and prone ventilation were independent risk factors affecting patient prognosis (all P < 0.05). Conclusion: Prone ventilation can improve oxygenation, reduce the risk of pulmonary infection, and decrease intracranial pressure in patients with severe traumatic brain injury combined with pulmonary infection, thereby improving patient prognosis. GCS score and APACHE II score can serve as important indicators for prognostic evaluation.

Transorbital point-of-care ultrasound versus fundoscopic papilledema to support treatment indication for potentially elevated intracranial pressure in children

PurposeTo compare transorbital point-of-care ultrasound techniques —optic nerve sheath diameter (US-ONSD) and optic disc elevation (US-ODE)— with fundoscopic papilledema to detect potentially raised intracranial pressure (ICP) with treatment indication in children.MethodsIn a prospective study, 72 symptomatic children were included, 50 with later proven disease associated with raised ICP (e.g. pseudotumour cerebri, brain tumour, hydrocephalus) and 22 with pathology excluded. Bilateral US-ONSD and US-ODE were quantified by US using a 12-MHz-linear-array transducer. This was compared to fundoscopic optic disc findings (existence of papilledema) and, in 28 cases, invasively measured ICP values.ResultsThe sensitivity and specificity of a cut-off value of US-ONSD (5.73 mm) to detect treatment indication for diseases associated with increased ICP was 92% and 86.4%, respectively, compared to US-ODE (0.43 mm) with sensitivity: 72%, specificity: 77.3%. Fundoscopic papilledema had a sensitivity of 46% and a specificity of 100% in this context. Repeatability and observer-reliability of US-ODE examination was eminent (Cronbach’s α = 0.978–0.989). Papilledema was detected fundoscopically only when US-ODE was > 0.67 mm; a US-ODE > 0.43 mm had a positive predictive value of 90% for potentially increased ICP.ConclusionIn our cohort, transorbital point-of-care US-ONSD and US-ODE detected potentially elevated ICP requiring treatment in children more reliably than fundoscopy. US-ONSD and US-ODE indicated the decrease in ICP after treatment earlier and more reliably than fundoscopy. The established cut-off values for US-ONSD and US-ODE and a newly developed US-based grading of ODE can be used as an ideal first-line screening tool to detect or exclude conditions with potentially elevated ICP in children.

Cerebral hemodynamic effects of head-up CPR in a porcine model

AimTo assess the hemodynamic effects of head elevation on cerebral perfusion during cardiopulmonary resuscitation (CPR) in a porcine model of cardiac arrest. MethodsVF was induced in eight 65 kg pigs that were treated with CPR after five minutes of no flow. Mean arterial pressure (MAP) was measured at the descending thoracic aorta. Internal carotid artery blood flow (CBF) was measured with an ultrasound probe. Cerebral perfusion pressure (CerPP) was calculated in two ways (CerPPICAP and CerPPreported) using the same intracranial pressure (ICP) measurement. CePPreported was calculated as MAP-ICP. CerPPICAP was calculated by using intracranial arterial pressure (ICAP) – ICP. The animals were switched between head up (HUP) and supine (SUP) CPR every five minutes for a total of twenty minutes of resuscitation. ResultsMAP and coronary perfusion pressure measurements were similar in both CPR positions (p = 0.36 and p = 0.1, respectively). ICP was significantly lower in the HUP CPR group (14.7 ± 1 mm Hg vs 26.9 ± 1 mm Hg, p < 0.001) as was ICAP (30.1 ± 2 mm Hg vs 42.6 ± 1 mmHg, p < 0.001). The proportional decrease in ICP and ICAP resulted in similar CerPPICAP comparing HUP and SUPCPR (p = 0.7). CBF was significantly lower during HUPCPR when compared to SUPCPR (58.5 ± 3 ml/min vs 78 ± 4 ml/min, p < 0.001). A higher CerPPreported was found during the HUP compared to SUP-CPR, when MAP was used (36.6 ± 2 mm Hg vs 23 ± 2 mm Hg, p < 0.001) without correcting for the hydrostatic pressure drop. ConclusionHUP did not affect cerebral perfusion pressure and it significantly decreased internal carotid blood flow.

Effects of caffeine on intracranial pressure and pain perception in freely moving rats.

Caffeine, a non-selective adenosine receptor (AR) antagonist, is the most consumed psychostimulant in the world. Caffeine has been suggested to regulate cerebrospinal fluid secretion and is known both to alleviate and to trigger headache; however, its effect on the regulation of intracranial pressure (ICP) is not known. Therefore, we aimed to investigate the effects of caffeine on ICP and nociceptive responses. Female Sprague-Dawley rats were implanted with a novel telemetric device for continuous ICP recordings, which allowed for continuous recordings in freely moving rats. A single dose of caffeine (30 or 120 mg/kg intraperitoneally) was given. In a second group (non-implanted), the acute effects of 30 mg/kg caffeine on periorbital threshold using Von Frey testing and spontaneous behavior were utilized using an automated behavioral registration platform (Laboratory, Animal, Behavior, Observation, Registration and Analysis System) in a randomized cross-over study. Quantitative polymerase chain reaction and immunofluorescence were used to localize ARs in the choroid plexus. A single dose of 30 mg/kg caffeine lowered the ICP by 35% at 165 min after administration (saline: 0.16 ± 0.9 vs caffeine: -1.18 ± 0.9 ΔmmHg, p = 0.0098) and lasted up to 12 h. Administration of 120 mg/kg caffeine showed a faster onset of decrease in ICP within 15 min by 50% (p = 0.0018) and lasted up to 12 h. The periorbital pain thresholds were higher after 1 h (saline: 224.6 ± 15.1 vs caffeine: 289.5 ± 8.7 g, p = 0.005) and lasted up to 5 h. Caffeine-treated rats had increased locomotor activity, speed, and changed grooming behavior. Expression of AR1 was found in the choroid plexus. This study demonstrates that caffeine has a lowering effect on ICP as an acute treatment. Interestingly, caffeine acutely caused an increased response in cephalic thresholds supporting hypoalgesic effects. Future studies investigating the beneficial effects of caffeine for elevated ICP are warranted.

Cerebrospinal Fluid Diversion for Refractory Intracranial Hypertension in Traumatic Brain Injury: A Single Center Experience

Diversion of cerebrospinal fluid (CSF) is a common neurosurgical procedure for control of intracranial pressure (ICP) in the acute phase after traumatic brain injury (TBI), where medical management is insufficient. CSF can be drained via an external ventricular drain (EVD) or, in selected patients, via a lumbar (external lumbar drain [ELD]) drainage catheter. Considerable variability exists in neurosurgical practice on their use. A retrospective service evaluation was completed for patients receiving CSF diversion for ICP control after TBI, from April 2015 to August 2021. Patients were included whom fulfilled local criteria deeming them suitable for either ELD/EVD. Data were extracted from patient notes, including ICP values pre/postdrain insertion and safety data including infection or clinically/radiologically diagnosed tonsillar herniation. Forty-one patients were retrospectively identified (ELD= 30 and EVD= 11). All patients had parenchymal ICP monitoring. Both modalities affected statistically significant decreases in ICP, with relative reductions at 1, 6, and 24 hour pre/postdrainage (at 24-hour ELD P < 0.0001, EVD P < 0.01). Similar rates of ICP control failure, blockage and leak occurred in both groups. A greater proportion of patients with EVD were treated for CSF infection than with ELD. One event of clinical tonsillar herniation is reported, which may have been in part attributable to ELD overdrainage, but which did not result in adverse outcome. The data presented demonstrate that EVD and ELD can be successful in ICP control after TBI, with ELD limited to carefully selected patients with strict drainage protocols. The findings support prospective study to formally determine the relative risk-benefit profiles of CSF drainage modalities in TBI.

Intracranial pressure changes during continuous renal replacement therapy in acute period of severe traumatic brain injury

The objective was to study the effect of continuous renal replacement therapy (CRRT) in the acute period of traumatic brain injury (TBI) on intracranial pressure (ICP). Materials and methods. An analysis of the dynamics of ICP during CRRT in patients with severe TBI was performed. The division of procedures into three groups, depending on the variant of ICP change, allowed to perform a comparative analysis of a number of factors that were potential predictors of aggravation of intracranial hypertension. Results. During CRRT, ICP decreased in 39 % of cases (Group 1) and increased in 29 % of cases (Group 2). In 32 % of cases (Group 3), ICP did not change significantly during the procedure. The initial sodium level and the degree of sodium decrease during the first 6 hours of the procedurediffered between the groups, which turned out to be significantly higher in the group 2. An inverse correlation was found between the change in sodium level during the first 6 hours of the procedure and the change in ICP. Conclusions. CRRT in the acute period of severe TBI can be associated with both a decrease and increase of ICP. The main risk factor for worsening intracranial hypertension during CRRT is hypernatremia.

Arterial and Intracranial Hypotension During and Following Exercise

Exercise induced arterial hypertension and post-exercise arterial hypotension (PEH) are well-described phenomena with direct impact on cerebral blood flow. Cerebral perfusion pressure is given by the difference between mean arterial pressure at brain-level (MAPbrain) and intracranial pressure (ICP), however, little is known about effects of moderate aerobic exercise on ICP. We hypothesize that moderate exercise does not increase ICP thereby facilitating the augmented cerebral blood flow and that a post-exercise decrease in ICP is a contributing mechanism to maintained cerebral blood flow during PEH.Non-invasive (N=14) and invasive (N=3) ICP recordings and cardiovascular parameters were measured upright and supine before, during, and after 30 minutes of seated moderate aerobic bicycle exercise. Exercise elevated MAPbrain from 68±4 to 82±7 mmHg (mean±SEM, P&lt;0.05) without elevating ICP, thus increasing CPP (72±3 to 87±6 mmHg, P&lt;0.05). Compared to before exercise, we found significant PEH with a decrease in MAPbrain of 5±3% (5 mmHg; P&lt;0.05), predominantly driven by a 26±5% (P&lt;0.0001) decrease in total peripheral resistance (TPR). Because post-exercise ICP decreased concomitantly by 58±20% (P&lt;0.0001) CPP remained unchanged. Recovery of ICP towards baseline was similarly correlated to TPR-recovery (R2=0.92, P&lt;0.001), all variables returned to baseline within one hour.Here, we show for the first time ICP during and following aerobic exercise and consequences for cerebral perfusion. Periodic PEH is cardio-vascular protective and has long-term benefits for hypertensive patients, here we suggest that post-exercise decreases in ICP could similarly be cerebo-protective and in part explain the long-term beneficial effects of exercise for cerebral health and cognition. This work was supported by NASA grant no 80NSSC19K0020 and the Novo Nordic Foundation grant no NNF15OC0019196 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effect of antisiphon devices on ventriculoperitoneal shunt drainage dynamics in growing children.

Infants and small children face changing boundary conditions when treated with a ventriculoperitoneal shunt (VPS) for hydrocephalus. There are no systematic data describing shunt drainage behavior and changes over time in a growing child. Using a child-adapted patient simulator, the authors investigated the drainage behaviors of fixed differential pressure (DP) valves and adjustable valves with devices for preventing overdrainage in children of different ages. Three miniNAV DP valves with a 10-cm H2O medium-pressure setting (MN10) and three adjustable proGAV2.0 valves with a 25-cm H2O gravitational unit (GU) at low 5-cm H2O opening pressure (PG5) and medium 10-cm H2O opening pressure (PG10) settings were each investigated with a hardware-in-the-loop test bed. This test bed consisted of a posture motion mechanism and two pressure compartments that mimicked intracranial and abdominal pressures and was used to test the VPS under realistic in vitro conditions. Body orientation and length were physically set according to the child's age. The software simulated the physiological situations of children aged 1, 5, and 10 years. All valves were tested according to these specifications, with 5 runs for 1 hour each in the horizontal, vertical, and horizontal positions. Intracranial pressure (ICP) and VPS flow were measured, and the respective cerebrospinal fluid volume changes and ICP set value were computed. The drainage parameters increased with age in all valves in the vertical position, with that of MN10 being pronounced in the 1-year-old simulation. The GU values in PG5 and PG10 substantially reduced drainage compared with MN10. PG10 prevented drainage in the 1-year-old and 5-year-old setups, but there was some drainage at physiological ICP in the 10-year-old setup. In contrast, MN10 produced the largest decreases in ICP across all ages and positions, and overdrainage resulted in insufficient ICP recovery in the subsequent horizontal position. ICP levels were mostly constant with PG10 at all ages. This study shows that unprotected DP valves may lead to overdrainage in infants, whereas low-pressure GU valves can prevent overdrainage through 5 years and medium-pressure GU valves admit physiological ICP through at least 10 years. Therefore, devices for preventing overdrainage should be included in the first implanted shunt, and opening pressure should be adjusted as the child grows.

Beyond intracranial pressure: monitoring cerebral perfusion and autoregulation in severe traumatic brain injury.

Severe traumatic brain injury (TBI) remains the most prevalent neurological condition worldwide. Observational and interventional studies provide evidence to recommend monitoring of intracranial pressure (ICP) in all severe TBI patients. Existing guidelines focus on treating elevated ICP and optimizing cerebral perfusion pressure (CPP), according to fixed universal thresholds. However, both ICP and CPP, their target thresholds, and their interaction, need to be interpreted in a broader picture of cerebral autoregulation, the natural capacity to adjust cerebrovascular resistance to preserve cerebral blood flow in response to external stimuli. Cerebral autoregulation is often impaired in TBI patients, and monitoring cerebral autoregulation might be useful to develop personalized therapy rather than treatment of one size fits all thresholds and guidelines based on unidimensional static relationships. Today, there is no gold standard available to estimate cerebral autoregulation. Cerebral autoregulation can be triggered by performing a mean arterial pressure (MAP) challenge, in which MAP is increased by 10% for 20 min. The response of ICP (increase or decrease) will estimate the status of cerebral autoregulation and can steer therapy mainly concerning optimizing patient-specific CPP. The role of cerebral metabolic changes and its relationship to cerebral autoregulation is still unclear and awaits further investigation.

Peak appearance time in pulse waveforms of intracranial pressure and cerebral blood flow velocity.

The shape of the pulse waveforms of intracranial pressure (ICP) and cerebral blood flow velocity (CBFV) typically contains three characteristic peaks. It was reported that alterations in cerebral hemodynamics may influence the shape of the pulse waveforms by changing peaks' configuration. However, the changes in peak appearance time (PAT) in ICP and CBFV pulses are only described superficially. We analyzed retrospectively ICP and CBFV signals recorded in traumatic brain injury patients during decrease in ICP induced by hypocapnia (n = 11) and rise in ICP during episodes of ICP plateau waves (n = 8). All three peaks were manually annotated in over 48 thousand individual pulses. The changes in PAT were compared between periods of vasoconstriction (expected during hypocapnia) and vasodilation (expected during ICP plateau waves) and their corresponding baselines. Correlation coefficient (rS) analysis between mean ICP and mean PATs was performed in each individual recording. Vasodilation prolonged PAT of the first peaks of ICP and CBFV pulses and the third peak of CBFV pulse. It also accelerated PAT of the third peak of ICP pulse. In contrast, vasoconstriction shortened appearance time of the first peaks of ICP and CBFV pulses and the second peak of ICP pulses. Analysis of individual recordings demonstrated positive association between changes in PAT of all three peaks in the CBFV pulse and mean ICP (rS range: 0.32-0.79 for significant correlations). Further study is needed to test whether PAT of the CBFV pulse may serve as an indicator of changes in ICP-this may open a perspective for non-invasive monitoring of alterations in mean ICP.

Is hypertonic saline an effective alternative to mannitol in the treatment of TBI in adult and pediatric patients? A systematic review and meta-analysis

Aim: This meta-analysis and systematic review aims to investigate and compare the efficacy of mannitol and hypertonic saline in treating patients who have suffered from traumatic brain injury (TBI). Methods: We reviewed publications from the Medline database, Web of Science, and Google Scholar from inception to 13 October 2022 with only English-based literature. The risk of bias from included Randomized controlled trial (RCT) s was assessed using the Cochrane Collaboration&amp;apos;s Tool. Newcastle-Ottawa Scale was employed to assess the included cohort\&amp;apos;s quality. The main outcomes of this review were treatment failure, mortality, intracranial pressure (ICP) reduction, and Cerebral Perfusion Pressure (CPP) increment. All the statistical analyses were performed using the Review Manager 5.4.1. A random-effects model was used to pool the studies when heterogeneity was seen, and the results were reported in the odds ratios (OR) and mean differences (MD) and the corresponding 95% confidence intervals. Results: The results of the statistical study found that there was a significantly lower treatment failure rate [OR = 1.80 (1.26, 2.57); p = 0.001; I 2 = 74%], the lower mortality rate [OR = 2.17 (1.26, 3.73); p = 0.005; I 2 = 0%], a greater increase in CPP [MD = -1.28 (-2.50, -0.05); p = 0.04; I 2 = 0%] associated with hypertonic saline treatment as compared to mannitol treatment. However, concerning ICP decrease, there was no significant difference between the two treatment options [MD = 1.86 (-0.64, 4.36); p = 0.14; I 2 = 70%]. Conclusions: Quantitative and qualitative analysis of trials and observational studies comparing the efficacy of hypertonic saline and mannitol demonstrates that hypertonic saline is a preferable treatment option with greater effectiveness and safety than mannitol in managing patients with TBI.

Evaluation of intra-cranial pressure changes by measuring the optic nerve sheath diameter during the lung recruitment maneuver in patients with acute respiratory distress syndrome: A prospective study.

The lung recruitment maneuver (LRM) applied in acute respiratory distress syndrome (ARDS) may increase the intra-cranial pressure (ICP). This study evaluated the effect of LRM on intra-cranial pressure changes in patients with ARDS by measuring the optic nerve sheath diameter (ONSD). LRM was applied to patients undergoing follow-up for ARDS, with a positive pressure of 30 cmH2O for 30 s. ONSD on ultra-sonography, dynamic lung compliance (Cdyn), oxygen saturation (SpO2), and hemodynamic parameters were measured before (T0), immediately after (T1), and 10 min after (T2) LRM. The primary endpoint was the effect of LRM on ONSD changes. The secondary endpoints included the effect of LRM on Cdyn, SpO2 change, and relationship between Cdyn and ONSD changes. The study included 60 patients. ONSD was higher at T1 than at T0 (median [interquartile range]: 5.13 [0.4] vs. 5.3 [0.3] mm, P < 0.001) but was similar at T0 and T2 (5.13 [0.4] vs. 5.09 [0.37] mm, P = 0.36). Cdyn and SpO2 were significantly higher at T1 and T2 than at T0 (Cdyn: 22.3 [5.8] vs. 23.7 [7.5] vs. 19.4 [6.6] mL/cmH2O, P < 0.001; SpO2: 90[2] vs. 92[4] vs. 88[4] %, P = 0.013). A significant correlation existed between Cdyn and ONSD changes, which increased at T2 compared to T0 (P < 0.001). LRM applied in ARDS causes a short-term increase in ONSD. However, Cdyn increases 10 min after LRM and causes ONSD, thereby leading to a decrease in ICP.

Comparative Effectiveness of Diversion of Cerebrospinal Fluid for Children With Severe Traumatic Brain Injury

Diversion of cerebrospinal fluid (CSF) has been used for decades as a treatment for children with severe traumatic brain injury (TBI) and is recommended by evidenced-based guidelines. However, these recommendations are based on limited studies. To determine whether CSF diversion is associated with improved Glasgow Outcome Score-Extended for Pediatrics (GOS-EP) and decreased intracranial pressure (ICP) in children with severe TBI. This observational comparative effectiveness study was performed at 51 clinical centers that routinely care for children with severe TBI in 8 countries (US, United Kingdom, Spain, the Netherlands, Australia, New Zealand, South Africa, and India) from February 2014 to September 2017, with follow-up at 6 months after injury (final follow-up, October 22, 2021). Children with severe TBI were included if they had Glasgow Coma Scale (GCS) scores of 8 or lower, had intracranial pressure (ICP) monitor placed on-site, and were aged younger than 18 years. Children were excluded if they were pregnant or an ICP monitor was not placed at the study site. Consecutive children were screened and enrolled, data regarding treatments were collected, and at discharge, consent was obtained for outcomes testing. Propensity matching for pretreatment characteristics was performed to develop matched pairs for primary analysis. Data analyses were completed on April 18, 2022. Clinical care followed local standards, including the use of CSF diversion (or not), with patients stratified at the time of ICP monitor placement (CSF group vs no CSF group). The primary outcome was GOS-EP at 6 months, while ICP was considered as a secondary outcome. CSF vs no CSF was treated as an intention-to-treat analysis, and a sensitivity analysis was performed for children who received delayed CSF diversion. A total of 1000 children with TBI were enrolled, including 314 who received CSF diversion (mean [SD] age, 7.18 [5.45] years; 208 [66.2%] boys) and 686 who did not (mean [SD] age, 7.79 [5.33] years; 437 [63.7%] boys). The propensity-matched analysis included 98 pairs. In propensity score-matched analyses, there was no difference between groups in GOS-EP (median [IQR] difference, 0 [-3 to 1]; P = .08), but there was a decrease in overall ICP in the CSF group (mean [SD] difference, 3.97 [0.12] mm Hg; P < .001). In this comparative effectiveness study, CSF diversion was not associated with improved outcome at 6 months after TBI, but a decrease in ICP was observed. Given the higher quality of evidence generated by this study, current evidence-based guidelines related to CSF diversion should be reconsidered.

Cisternostomy versus Decompressive Craniectomy for the Management of Traumatic Brain Injury: A Randomized Controlled Trial

The goal of treatment of traumatic brain injury (TBI) is to avoid secondary brain injury. Decompressive craniectomy has been shown to reduce intracranial pressure (ICP), but it actually provides an outlet for brain tissue to expand without reducing edema. Basal cisternostomy is an emerging microsurgical technique to manage cerebral edema in TBI. Cerebrospinal fluid is released from basal cisterns, which reduces cerebral edema. We compared outcomes of cisternostomy with decompressive craniectomy in a randomized controlled trial and studied the effectiveness of cisternostomy in decreasing cerebral edema. All enrolled patients were randomly assigned to 2 groups and assessed clinically and radiologically. TBIs were categorized as mild, moderate, and severe injuries, and Marshall computed tomography-based score was assessed. Intraoperative ICP was measured in both groups. Outcomes were assessed based on postoperative intensive care unit stay, days on ventilator support, and Glasgow Outcome Scale score. There were 50 patients randomly assigned to 2 groups (25 patients in each group). Mortality rate was 32% (8 deaths) in the cisternostomy group and 44% (11 deaths) in the decompressive craniectomy group. Patients in the cisternostomy group had decreased mean days of ventilator support and intensive care unit stay. Cisternostomy resulted in significant decreases in ICP after craniotomy. Age, time from trauma to surgery, and Marshall score showed prognostic importance on outcomes. Cisternostomy was effective in reducing ICP in patients with TBI. Good Glasgow Outcome Scale scores and low rates of complications were found in the postoperative period after cisternostomy. Age, presenting Glasgow Coma Scale score, Marshall score, other major injuries, and time from trauma to surgery had a significant prognostic impact on outcome in management of TBI.

Neuroprotective Effects of the Inert Gas Argon on Experimental Traumatic Brain Injury In Vivo with the Controlled Cortical Impact Model in Mice.

Simple SummaryTraumatic brain injuries remain one of the leading causes of death in the western world and developing countries. There is an urgent need for causal therapies for such injuries. The noble gas argon has already shown promising results in in-vitro models. The influence of argon on the extent of damage after a craniocerebral trauma will be investigated in this study, in vivo, in mice. After the trauma, the animals were examined for neurological impairments and their brains were removed to detect brain edema and microscopically detectable alterations.Argon has shown neuroprotective effects after traumatic brain injury (TBI) and cerebral ischemia in vitro and in focal cerebral ischemia in vivo. The purpose of this study is to show whether argon beneficially impacts brain contusion volume (BCV) as the primary outcome parameter, as well as secondary outcome parameters, such as brain edema, intracranial pressure (ICP), neurological outcome, and cerebral blood flow (CBF) in an in-vivo model. Subjects were randomly assigned to either argon treatment or room air. After applying controlled cortical impact (CCI) onto the dura with 8 m/s (displacement 1 mm, impact duration 150 ms), treatment was administered by a recovery chamber with 25%, 50%, or 75% argon and the rest being oxygen for 4 h after trauma. Two control groups received room air for 15 min and 24 h, respectively. Neurological testing and ICP measurements were performed 24 h after trauma, and brains were removed to measure secondary brain damage. The primary outcome parameter, BCV, and the secondary outcome parameter, brain edema, were not significantly reduced by argon treatment at any concentration. There was a highly significant decrease in ICP at 50% argon (p = 0.001), and significant neurological improvement (beamwalk missteps) at 25% and 50% argon (p = 0.01; p = 0.049 respectively) compared to control.

The Impact of a Cervical Collar on Intracranial Pressure in Traumatic Brain Injury Patients: A Systematic Review and Meta-Analysis

Purpose: Although the use of a cervical collar in the prehospital setting is recommended to prevent secondary spinal cord injuries and ensure spinal immobilization, it is not known what effects this has on raising intracranial pressure (ICP) in traumatic brain injury (TBI) patients. In the absence of studies measuring ICP in the prehospital setting, the aim of this study was to systematically review the data related to ICP changes measured after presentation at the hospital in patients who had arrived wearing cervical collars. Methods: We searched Medline (PubMed), Embase, CINAHL, and Google Scholar for studies that investigated in-hospital ICP changes in TBI patients arriving at the hospital wearing collars. Titles, abstracts, and full texts were then searched for inclusion in the study. A narrative synthesis, as well as a meta-analysis, was performed. Results: Of the 1006 studies identified, only three met the inclusion/exclusion criteria. The quality of the three included studies was moderate and the risk of bias was low. All three studies used the Laerdal Stifneck collar, but all studies showed an increase in ICP after application of the collar. A further three studies that measured ICP but did not fit the systematic search were also included due to low patient numbers. A meta-analysis of the pooled data confirmed a significant increase in ICP, although between the four studies, only 77 patients were included. The meta-analysis also confirmed that after removal of the collar, there was a significant decrease in ICP. Conclusions: Our study suggests that the use of a cervical collar increases ICP in TBI and head injury patients, which may have detrimental effects. However, due to the extremely low sample size from all six studies, caution must be exercised when interpreting these data. Thus, further high-quality research is necessary to unequivocally clarify whether cervical collars should be used in patients with TBI.

Changes in Blood Pressure and Heart Rate during Decompressive Craniectomy.

ObjectiveRapid increase in intracranial pressure (ICP) can result in hypertension, bradycardia and apnea, referred to as the Cushing phenomenon. During decompressive craniectomy (DC), rapid ICP decreases can cause changes in mean atrial blood pressure (mABP) and heart rate (HR), which may be an indicator of intact autoregulation and vasomotor reflex. MethodsA total of 82 patients who underwent DC due to traumatic brain injury (42 cases), hypertensive intracerebral hematoma (19 cases), or major infarction (21 cases) were included in this prospective study. Simultaneous ICP, mABP, and HR changes were monitored in one minute intervals during, prior to and 5–10 minutes following the DC. ResultsAfter DC, the ICP decreased from 38.1±16.3 mmHg to 9.5±14.2 mmHg (p<0.001) and the mABP decreased from 86.4±14.5 mmHg to 72.5±11.4 mmHg (p<0.001). Conversly, overall HR was no significantly changed in HR, which was 100.1±19.7 rate/min prior to DC and 99.7±18.2 rate/min (p=0.848) after DC. Notably when the HR increased after DC, it correlated with a favorable outcome (p<0.001), however mortality was increased (p=0.032) when the HR decreased or remained unchanged. ConclusionIn this study, ICP was decreased in all patients after DC. Changes in HR were an indicator of preserved autoregulation and vasomotor reflex. The clinical outcome was improved in patients with increased HR after DC.

Improved Pressure Equalization Ratio Following Mannitol Administration in Patients With Severe TBI: A Preliminary Study of a Potential Bedside Marker for Response to Therapy.

BackgroundPerforming a cerebrospinal fluid (CSF) drainage challenge can be used to measure the pressure equalization (PE) ratio, which describes the extent to which CSF drainage can equalize pressure to the height of the external ventricular drain and may serve as a correlate of cerebral edema. We sought to assess whether treatment with mannitol improves PE ratio in patients with severe traumatic brain injury (TBI) with elevated intracranial pressure (ICP).MethodsWe studied consecutive patients with TBI and brain edema on computed tomography scan and an external ventricular drain (EVD), admitted to the neurointensive care unit. PE ratio, defined as ICP prior to CSF drainage minus ICP after CSF drainage divided by ICP prior to CSF drainage minus EVD height, was measured as previously described. Patients were treated with mannitol for raised ICP based on clinical indication and PE ratio measured before and after mannitol administration.ResultsWe studied 20 patients with severe TBI with raised ICP. Mean ICP prior to mannitol treatment was 29 ± 7 mm Hg. PE ratio rose substantially after mannitol treatment (0.62 ± 0.24 vs. 0.29 ± 0.20, p < 0.0001), indicating an improved ability to drain CSF and equalize ICP with the preset height of the EVD. The combination of mannitol and CSF drainage led to an improved reduction in ICP compared with that seen before mannitol therapy (11 ± 2 mm Hg vs. 6 ± 2 mm Hg, p < 0.01), and led to a decrease in ICP below the 20 mm Hg threshold in 77% of cases.ConclusionsTreatment with mannitol leads to a substantial improvement in PE ratio that reflects the ability to achieve a greater decrease in ICP when CSF drainage is performed after mannitol administration. This preliminary study raises the possibility that PE ratio may be useful to follow response to therapy in patients with cerebral edema and raised ICP. Further studies to determine whether PE ratio may serve as an easily obtained and clinically useful surrogate marker for the extent of brain edema are warranted.

Verticalization for Refractory Intracranial Hypertension: A Case Series.

Severe intracranial hypertension is strongly associated with mortality. Guidelines recommend medical management involving sedation, hyperosmotic agents, barbiturates, hypothermia, and surgical intervention. When these interventions are maximized or are contraindicated, refractory intracranial hypertension poses risk for herniation and death. We describe a novel intervention of verticalization for treating intracranial hypertension refractory to aggressive medical treatment. This study was a single-center retrospective review of six cases of refractory intracranial hypertension in a tertiary care center. All patients were treated with a standard-of-care algorithm for lowering intracranial pressure (ICP) yet maintained an ICP greater than 20mmHg. They were then treated with verticalization for at least 24h. We compared themedian ICP, the number of ICP spikes greater than 20mmHg, and the percentage of ICP values greater than 20mmHg in the 24h before verticalization vs. after verticalization. We assessed the use of hyperosmotic therapies and any changes in the mean arterial pressure and cerebral perfusion pressure related with the intervention. Five patients were admitted with subarachnoid hemorrhage and one with intracerebral hemorrhage. All patients had ICP monitoring by external ventricular drain. The median opening pressure was 30mmHg (25th-75th interquartile range 22.5-30mmHg). All patients demonstrated a reduction in ICP after verticalization, with a significant decrease in the median ICP (12 vs. 8mmHg; p < 0.001), the number of ICP spikes (12 vs. 2; p < 0.01), and the percentage of ICP values greater than 20mmHg (50% vs. 8.3%; p < 0.01). There was a decrease in total medical interventions after verticalization (79 vs. 41; p = 0.05) and a lower total therapy intensity level score after verticalization. The most common adverse effects included asymptomatic bradycardia (n = 3) and pressure wounds (n = 4). Verticalization is an effective noninvasive intervention for lowering ICP in intracranial hypertension that is refractory to aggressive standard management and warrants further study.

The effect of xylazine on intracranial pressure in anesthetized and standing horses.

To determine the effect of xylazine on intracranial pressure (ICP) in standing compared to isoflurane-anesthetized horses. Prospective, crossover study design. University Teaching Hospital. Six adult horses donated to the University. Horses were determined to be healthy via physical examination, complete blood count, and neurological evaluation. Horses were anesthetized, maintained on isoflurane in oxygen in left lateral recumbency, and ventilated to normocapnia. Horses were instrumented for intraparenchymal measurement of ICP, invasive blood pressure, pulse oximetry, and end tidal gas analyzer. Xylazine 1mg/kg was administered IV and ICP, systolic arterial pressure, mean arterial pressure (MAP), diastolic arterial pressure, and heart rate were recorded and cerebral perfusion pressure (CPP) was calculated for the following 15 minutes. Twenty-four to 36hours following anesthetic recovery, xylazine 1mg/kg was administered IV and ICP, heart rate, and Doppler blood pressure (BPdop) on the tail were monitored for 15 minutes. There was a decrease in ICP following administration of xylazine in anesthetized horses (P<0.003) but not standing horses (P=0.227). There was an increase in systolic arterial pressure, MAP, diastolic arterial pressure (P<0.001), and BPdop (P=0.001) following administration of xylazine. As a result, CPP increased in anesthetized horses (P<0.03). There was a negative association between ICP and MAP in anesthetized horses (P=0.007) but not ICP and BPdop conscious horses (P=0.379). Administration of xylazine to anesthetized horses resulted in an increased CPP due to decreased ICP with concurrent increased MAP. Administration of xylazine to standing horses did not result in a change in ICP. However, with the increase in BPdop found in awake horses, it is likely that CPP would also increase in awake horses following xylazine administration.