Intracranial dynamics biomarkers at traumatic cerebral vasospasm.

Introduction: Patients who suffer severe traumatic brain injury (sTBI) and cerebral vasospasm (CVS) frequently have posttraumatic cerebral ischemia (PCI). The research question: was to study changes in cerebral microcirculatory bed parameters in sTBI patients with CVS and with or without PCI. Material and methods: A total of 136 severe TBI patients were recruited in the study. All patients underwent perfusion computed tomography, intracranial pressure monitoring, and transcranial Doppler. The levels of cerebrovascular resistance (CVR), cerebral arterial compliance (CAC), cerebrovascular time constant (CTC), and critical closing pressure (CCP) were measured using the neuromonitoring complex. Statistical analysis was performed using parametric and nonparametric methods and factor analysis. The patients were dichotomized into PCI-positive (n = 114) and PCI-negative (n = 22) groups. Data are presented as mean values (standard deviations). Results: CVR was significantly increased, whereas CAC, CTC, and CCP were significantly decreased in sTBI patients with CVS and PCI development (p < 0.05). Factor analyses revealed that all studied microcirculatory bed parameters were significantly associated with the development of PCI (p < 0.05). Discussion and conclusion: The changes in all studied microcirculatory bed parameters in TBI patients with CVS were significantly associated with PCI development, which enables us to regard them as the biomarkers of CVS and PCI development. The causes of the described microcirculatory bed parameters changes might include complex (cytotoxic and vasogenic) brain edema development, regional microvascular spasm, and dysfunction of pericytes. A further prospective study is warranted.

Arteriovenous cerebral blood flow correlation in moderate-to-severe traumatic brain injury: CT perfusion study.

Introduction: The relationship between arterial and venous blood flow in moderate-to-severe traumatic brain injury (TBI) is poorly understood. The research question: was to compare differences in perfusion computed tomography (PCT)-derived arterial and venous cerebral blood flow (CBF) in moderate-to-severe TBI as an indication of changes in cerebral venous outflow patterns referenced to arterial inflow. Material and methods: Moderate-to-severe TBI patients (women 53; men 74) underwent PCT and were stratified into 3 groups: I (moderate TBI), II (diffuse severe TBI without surgery), and III (severe TBI after the surgery). Arterial and venous CBF were measured by PCT in both the internal carotid arteries (CBFica) and the confluence of upper sagittal, transverse, and straight sinuses (CBFcs). Results: In group I, CBFica on the left and right sides were significantly correlated with each other (p < 0.0001) and with CBFcs (p = 0.048). In group II, CBFica on the left and right sides were also correlated (P < 0.0000001) but not with CBFcs. Intracranial pressure reactivity (PRx) and CBFcs were correlated (p = 0.00014). In group III, CBFica on the side of the removed hematoma was not significantly different from the opposite CBFica (P = 0.680) and was not correlated with CBFcs. Discussion and conclusion: The increasing severity of TBI is accompanied by a rising uncoupling between the arterial and venous CBF in the supratentorial vessels suggesting a shifting of cerebral venous outflow.

Dynamics of Intracranial Pressure and Cerebrovascular Reactivity During Intrahospital Transportation of Traumatic Brain Injury Patients in Coma.

BACKGROUND: Intrahospital transportation (IHT) of patients with traumatic brain injury (TBI) is common and may have adverse consequences, incurring inherent risks. The data on the frequency and severity of clinical complications linked with IHT are contradictory, and there is no agreement on whether it is safe or potentially challenging for neurocritical care unit patients. Continuous intracranial pressure (ICP) monitoring is essential in neurointensive care. The role of ICP monitoring and management of cerebral autoregulation impairments in IHT of patients with severe TBI is underinvestigated. The purpose of this nonrandomized retrospective single-center study was to assess the dynamics of ICP and an improved pressure reactivity index (iPRx) as a measure of autoregulation during IHT. METHODS: Seventy-seven men and fourteen women with severe TBI admitted in 2012-2022 with a mean age of 33.2 ± 5.2 years were studied. ICP and arterial pressure were invasively monitored, and cerebral perfusion pressure and iPRx were calculated from the measured parameters. All patients were subjected to dynamic helical computed tomography angiography using a 64-slice scanner Philips Ingenuity computed tomography scan 1-2 days after TBI. Statistical analysis of all results was done using a paired t-test, and p was preset at < 0.05. The logistic regression analysis was performed for cerebral ischemia development dependent on intracranial hypertension and cerebrovascular reactivity. RESULTS: IHT led to an increase in ICP in all the patients, especially during vertical movement in an elevator (maximum 75.2 mm Hg). During the horizontal transportation on the floor, ICP remained increased (p < 0.05). The mean ICP during IHT was significantly higher (26.1 ± 13.5 mm Hg, p < 0.001) than that before the IHT (19.9 ± 5.3 mm Hg). The mean iPRx after and before IHT was 0.52 ± 0.04 and 0.23 ± 0.14, respectively (p < 0.001). CONCLUSIONS: Both horizontal and vertical transportation causes a significant increase in ICP and iPRx in patients with severe TBI, potentially leading to the outcome worsening.

Changes of Arterial and Venous Cerebral Blood Flow Correlation in Moderate-to-Severe Traumatic Brain Injury: A CT Perfusion Study.

We compared differences in perfusion computed tomography (PCT)-derived arterial and venous cerebral blood flow (CBF) in moderate-to-severe traumatic brain injury (TBI) as an indication of changes in cerebral venous outflow patterns referenced to arterial inflow. Moderate-to-severe TBI patients (women 53; men 74) underwent PCT and were stratified into 3 groups: I (moderate TBI), II (diffuse severe TBI without surgery), and III (diffuse severe TBI after the surgery). Arterial and venous CBF was measured by PCT in both the middle cerebral arteries (CBFmca) and the upper sagittal sinus (CBFuss). In group I, CBFmca on the left and right sides were significantly correlated with each other (p < 0.0001) and with CBFuss (p = 0.048). In group II, CBFmca on the left and right sides were also correlated (p < 0.0000001) but not with CBFuss. Intracranial pressure reactivity (PRx) and CBFuss were correlated (p = 0.00014). In group III, CBFmca on the side of the removed hematoma was not significantly different from the opposite CBFmca (p = 0.680) and was not correlated with CBFuss. Conclusions: The increasing severity of TBI is accompanied by an impairment of the correlation between the arterial and venous CBF in the supratentorial vessels suggesting shifting in arterial and venous CBF in severe TBI associated with increased ICP reflected by PRx.

Moderate Severity SARS-CoV-2 (COVID-19) Affects Ocular Vergence Indices: Eye Tracking-Based Study.

OBJECTIVE: Since the start of the SARS-CoV-2 (COVID-19) pandemic, it has become clear that the brain is one of the main targets for acute and chronic damage. Although neurodegenerative changes have yet to be investigated, there is already a large body of data on damage to its fiber tracts. A mobile eye tracker is possibly one of the best tools to study such damage in a COVID hospital setting. At the same time, the available data indicate that eye tracking parameters, even in healthy volunteers, demonstrate a distinct gender-specific difference.The aim of the work is to evaluate functional and structural impairments of the fiber tracts and to find possible gender-specific dynamics of eye tracking indicators in the acute period of COVID-19 pneumonia (Delta variant) of moderate severity. MATERIALS AND METHODS: A single-center non-randomized retrospective study included 84 patients in the acute period of moderate severity SARS-CoV-2 (COVID-19) pneumonia (Delta variant) (Group 1). The mean time from admission was 1.4 ± 1.2 days. M:41, F:43. According to thoracic CT, the lung involvement ranged from CT 1 to CT 2. SpO2 ranged from 95% to 99%. The mean age was 35.5 ± 14.8 years (from 18 to 60). The control group (Group 2) included 158 healthy volunteers without pathology of the vision organs and central nervous system.The eye vergence index (VRx) was determined using eye tracking as a motion correlation coefficient between the angular velocities of the left and right eyeballs and was a measure of the conjugation of horizontal and vertical eye movements.The mobile complex Eye Tracker Low-Speed 20 (BVG LLC, the Netherlands) was used. Eye tracking parameters were assessed by vertical and horizontal eye vergence (VVRx and HVRx).Statistical analysis was done using the methods of parametric and non-parametric statistics. RESULTS: Moderate COVID-19 pneumonia resulted in a significant decrease in both VVRx and HVRx compared to controls (0.763 ± 0.127 and 0.856 ± 0.043; p < 0.000001; 0.729 ± 0.018 and 0.776 ± 0.023 p < 0.000001, respectively). VVRx values were significantly higher in men (0.775 ± 0.046 and 0.747 ± 0.091, p = 0.019, respectively), while Ð¥VRx values were significantly higher in women (0.665 ± 0.018 and 0.728 ± 0.024, p < 0.0000001, respectively). CONCLUSIONS: SARS-CoV-2 (COVID-19) of moderate severity is accompanied by a significant deterioration in eye tracking performance proving functional and structural impairments (p < 0.05). VVRx was significantly higher in men, and HVRx was substantially greater in women reflecting gender-specific differences.

NIRS-Based Study of Local Cerebral Oxygenation During Transcranial Direct Current Stimulation in Patients with Mild Traumatic Brain Injury.

The purpose of our study was to assess the dynamics of local cerebral oxygenation (LCO) by near-infrared spectroscopy (NIRS) during transcranial direct current stimulation (tDCS) in the acute stage of mild traumatic brain injury (mTBI). Fifty-seven mTBI patients (18 women and 39 men, 35 ± 11.7 years old, GCS 13.7 ± 0.7) were treated by tDCS at 3-5 days after head injury. Stimulation parameters were: 1 mA, 9 V, duration-20 min. A cerebral oximeter was used to assess LCO-values in the frontotemporal lobes. Anodal and cathodal LCO values were compared before tDCS and every 2 min until the tDCS end. Significance was preset to p < 0.05. Results: A significant decrease in LCO values on the anodal side was observed at the 8th to 12th minutes of stimulation, compared to the cathodal side (at 8th minute - p = 0.011; at 12th minute - p < 0.00000001) and compared to LCO values before tDCS (p < 0.00001). The LCO on the cathodal side was not significantly different during the whole tDCS. At the end of the procedure, the interhemispheric LCO differences were not statistically significant (p = 0.757). Conclusions: Transcranial DCS in 3-5 days of mTBI leads to a significant decrease in the LCO value on the anodal side between 8 and 12 min and subsequent recovery to baseline values by the end of the procedure.

Critical Closing Pressure of Cerebral Circulation at Concomitant Moderate-to-Severe Traumatic Brain Injury.

BACKGROUND: Critical closing pressure (CrCP) is the pressure below which local pial blood pressure is inadequate to prevent blood flow cessation. The state of cerebral CrCP in patients with concomitant moderate-to-severe traumatic brain injury (cTBI) after brain lesions surgery remains poorly understood. AIM: The aim of our study was to establish the dynamics of CrCP after intracranial surgery in traumatic brain injury (TBI) patients with polytrauma. MATERIAL AND METHODS: Results of the treatment of 70 patients with moderate-to-severe сTBI were studied (Male: Female - 39:31, mean age -33.2 ± 12.2 years). Depending on intracranial surgery, patients were divided into 2 groups. All patients were subjected to transcranial Doppler of both middle cerebral arteries, and evaluation of mean arterial pressure (MAP). Based on the data obtained, CrCPs were calculated. Significance was preset to P < 0.05. RESULTS: Mean CrCP values in each group were significantly higher than a reference range (р < 0.01). There was no significant difference in CrCP values between the left and right hemispheres in the group 1 (p = 0.789). In the group 2, mean CrCP values on the unoperated side remained significantly lower than on the operated side (p = 0.000011) even after intracranial surgery. In group 1, mean CrCP values were significantly lower than on the surgery side in the group 1 (Z = 3,4; р = 0.043). CONCLUSION: CrCP values in concomitant moderate-to-severe TBI after removing brain lesions and without surgery were significantly higher than referral data. Even after removal of brain lesions volumes in patients with concomitant moderate-to-severe TBI, CrCP values on the surgery side remained markedly higher than on the side opposite to the removed lesion volumes.

NIRS-Based Assessment of Cerebral Oxygenation During High-Definition Anodal Transcranial Direct Current Stimulation in Patients with Posttraumatic Encephalopathy.

The aim was to evaluate the changes in brain tissue oxygenation, assessed by near-infrared spectroscopy (NIRS) during high-definition transcranial direct current stimulation (HD-tDCS) in patients with posttraumatic encephalopathy (PTE). Fifty-two patients with PTE after diffuse, blunt, non-severe traumatic brain injury (TBI) (14 women and 38 men, 31.8 ± 12.5 years, Glasgow Coma Score before tDCS 13.2 ± 0.3) were treated with HD-tDCS at 21 days after TBI. The parameters were as follows: 1 mA, 9 V, and current density ~0.15 mA/cm2. The duration of HD-tDCS was 30 min. The anodal and cathodal electrodes were placed over the left M1 and contralateral supraorbital region, respectively. HD-tDCS was delivered by a direct current stimulator with a pair of surface sponge electrodes (S = 3 cm2). Regional cerebral oxygen saturation (SctO2) in the frontal lobes was measured simultaneously and bilaterally by the cerebral oximeter. SctO2 values were compared before stimulation, by the 15th minute and at the end of the tDCS. Significance was preset to p < 0.05. Results. Before the stimulation, SctO2 values varied between 53% and 86% (74 ± 7.1%) without significant difference between hemispheres (p = 0.135). After 15 min, a significant (p < 0.0000001) decrease in regional SctO2 on the anodal side was observed (mean 54.5 ± 5.6%). On the cathodal side, SctO2 remained unchanged. At the end of the stimulation (30 min), differences between the hemispheres in SctO2 remained statistically significant (p < 0.05). Conclusions. In patients with PTE complicated by TBI, HD-tDCS causes a statistically significant (p < 0.05) decrease in regional SctO2 on the anodal side.

Cerebral Critical Closing Pressure in Concomitant Traumatic Brain Injury and Intracranial Hematomas.

The critical closing pressure (CrCP) is the pressure below which the local pial blood pressure is inadequate to prevent blood flow cessation. The cerebral CrCP in concomitant traumatic brain injury (TBI) and intracranial hematomas (TBI + ICH) remains understudied. The aim was to determine the status of the CrCP at сTBI with and without the ICH development. MATERIAL AND METHODS: The results of the treatment of 90 patients with severe to moderate сTBI were studied (male/female - 49:41). The average age was 34.2 ± 14.4 years. Depending on the presence of ICH, patients were divided into two groups. All patients were subjected to transcranial Doppler of the both middle cerebral arteries, and evaluation of mean arterial pressure (MAP). Based on data obtained, the CrCPs were calculated. Significance was preset to p < 0.05. RESULTS: The mean CrCP values in each group appeared to be significantly higher than a referral value (р < 0.05). The mean CrCP values in the perifocal zone of removed hematoma were significantly higher than in TBI patients without ICH (р = 0.015 and р = 0.048, respectively). Analysis of CrCP values in various types of ICH showed no statistically significant differences (р > 0.05). DISCUSSION: The CrCP significantly differs in the groups of TBI patients with and without ICH. The comparability of the groups in respect to the concomitant injury structure proves that the revealed CrCP changes result from the traumatic compression of the brain.

Comparative Analysis of Simultaneous Transcranial Doppler and Perfusion Computed Tomography for Cerebral Perfusion Evaluation in Patients with Traumatic Brain Injury.

The aim was to investigate the feasibility of simultaneous comparison of cerebral circulation in major vessels and microvasculature in patients suffering traumatic brain injury (TBI) with or without intracranial hematomas (IH). METHODS: 170 patients were divided into two groups: Group 1 - diffuse TBI (75 patients); and Group 2 - TBI with IH (95 patients: 18 epidural, 65 subdural and 12 multiple). Perfusion computed tomography (PCT) for assessment of volumetric cerebral blood flow (CBF) was done 2-15 days after admission to hospital. Simultaneous assessment of cerebral blood flow velocity (CBFV) in both middle cerebral arteries was done by transcranial Doppler. RESULTS: In patients with diffuse TBI, CBF had statistically valid correlations with CBFV (r = 0.28, p = 0.0149 on the left side; r = 0.382, p = 0.00075 on the right side). In patients with TBI and IH, the analysis did not reveal any reliable correlations between the CBFV and CBF velocity in the temporal lobes, either on the side of the removed IH or on the opposite side. CONCLUSION: The greatest linear correlation was noted in patients with diffuse TBI without the development of a coarse shift of the midline structures and dislocation syndrome. This correlation decreases with the increase in injury severity and development of secondary complications in the acute period, which probably reflects impairment of the coupling of oxygen consumption by brain tissue and cerebral microcirculation.