Cerebral Oxygen Research Articles

High-altitude cerebral oxygen saturation detection using wireless wearable cerebral oximeter.

Hypobaric hypoxic conditions encountered at high altitudes can significantly impact the physiological functions of human body. Therefore, accurate and real-time monitoring of physiological characteristics is crucial for the prevention of brain injuries in individuals with acute and chronic high-altitude exposure. In this study, a wireless wearable cerebral oximeter (WORTH band) was used for the continuous, real-time monitoring of physiological parameters, including regional cerebral oxygen saturation (rSO2) and heart rate (HR), among subjects with high-altitude exposure. During the high-altitude (from 46 m to 4300 m) expedition task, there was a significant decrease in rSO2 accompanied by a corresponding increase in heart rate as the altitude increased. Additionally, during the long-term (52 days) high-altitude (from 356 m to 4658 m) cycling task, the altitudes were significantly correlated with the rSO2 and SpO2 in the elderly subjects. The current findings indicate that the WORTH band oximeter can serve as a promising instrument for measuring rSO2 at high altitudes. We hope that the insights derived from this study could contribute to the management of cerebral oxygenation for individuals with high-altitude exposure and further expand the existing understanding of brain functional detection at high altitudes.

Investigating Transcutaneous Vagus Nerve Stimulation in Amnestic Mild Cognitive Impairment

Abstract Background New treatments are urgently needed for individuals with Mild Cognitive Impairment (MCI) - in particular for those with amnestic MCI, of whom a high proportion have underlying Alzheimer's Disease (AD). Transcutaneous Vagus Nerve Stimulation (tVNS) is a non-invasive neuro-modulatory treatment which has not been extensively examined in older adults with amnestic MCI. Methods A single site, single-blind, randomised three-arm crossover pilot trial of acute (60 minutes) tVNS (baseline, sham or active stimulation) was conducted a Regional Specialist Memory Service. Forty participants (age 71.7 ±6.9; 22/40 male) with diagnosed amnestic MCI were recruited. Given the links between AD and neuro-cardiovascular instability, potential adverse effects of active tVNS were assessed using beat-to-beat peripheral (Blood Pressure (BP) and Heart Rate [HR]) and central (via Near Infra-red Spectroscopy) haemodynamic responses to Active Stand (AS). Cognition was assessed between 21.3 ±4.9 and 60.5 ±4.4 minutes using a domain-specific cognitive performance battery with results analysed using mixed-effects linear regression. Results In older adults with amnestic MCI, tVNS was safe, tolerable and acceptable with 98% of participants stating they would use the device again. There was no significant effect on BP, or HR responses to AS and cerebral oxygenation remained stable during AS. After tVNS stimulation, performance on tests of spatial navigation were significantly improved compared to both baseline (ß= -8.76; [-14.91, -2.56]; p=0.01) and sham (ß= -4.15; [-7.32, -0.99]; p=0.01) conditions. Conclusion tVNS is a safe and tolerable treatment modality in older adults with amnestic MCI. Future studies should explore sustained effects and feasibility of domiciliary use.

Cerebral Hypoperfusion And Future Falls Risk Among Community Dwelling Older Adults with Orthostatic Hypotension

Abstract Background Falls occur in approximately 33% of those over 65 annually, with 10-20% resulting in injury or hospitalisation. Orthostatic Hypotension (OH) characterised by significant blood pressure (BP) drops upon standing is frequently identified in those with unexplained falls (UF). Cerebral hypoperfusion is regarded as the mechanism by which OH contributes to falls risk. However, work looking at the direct interaction between OH, cerebral perfusion and falls is lacking. Methods Near Infrared Spectroscopy (NIRS) derived frontal lobe cerebral oxygenation (reported as tissue saturation index (TSI)) and continuous beat-to-beat BP by finometer were measured in parallel during active standing among participants aged ≥55 at wave3 of TILDA (n=2478). OH, was defined as persisting systolic BP drop ≥20mmHg and/or diastolic BP drop ≥10mmHg at 30, 60 and 90seconds post standing. TSI drop from baseline ≥75th centile at 30seconds informed the “greater TSI drop” variable for longitudinal analysis. Multilevel linear regression models assessed the association between change in TSI from baseline and OH. Multilevel logistic regression models assessed the longitudinal relationship between OH, cerebral perfusion and future UF at 4years follow up (waves 4-5). Results Twenty percent had OH and were more likely to be older and have cardiovascular disease. TSI drops from baseline after standing were significantly greater in those with OH at 30 (beta=0.32 [CI 0.15-0.49]; p<0.001), 60 (beta=0.41 [CI 0.23-0.6]; p<0.001), and 90 (beta=0.46 [CI 0.27-0.65]; p<0.001) seconds in fully adjusted models. After robust adjustment, combination of OH with greater TSI drops was strongly associated with future UF (Odds Ratio (OR) 2.23 [CI 1.35-3.69]; p=0.002), while OH and lower TSI drops were not (OR 1.27 [CI 0.87-1.85]; p=0.216). Conclusion These novel findings confirm that degree of cerebral hypoperfusion on standing informs risk of future UF in those with OH and has important clinical implications for the risk assessment of older people presenting with falls.

The role of endothelial frequency in the cerebral blood flow control during neonatal asphyxia: a retrospective longitudinal study

BackgroundCerebral blood flow dynamics can be explored through analysis of endothelial frequencies. Our hypothesis posits a disparity in endothelial activity among neonates with perinatal asphyxia, stratified by the presence or absence of neuronal lesions.MethodsWe conducted a retrospective longitudinal study involving newborns treated with hypothermia for moderate to severe asphyxia. Participants were grouped based on the presence or absence of neuronal damage to investigate temporal endothelial involvement in cerebral blood flow regulation. Regional cerebral oxygen saturation (rScO2) was measured using near-infrared spectroscopy (NIRS), and temporal series were analyzed in the frequency domain, utilizing the original frequency of the INVOS™ device.ResultsThe study included 88 patients, with 53% (47/88) being male and 33% (29/88) demonstrating brain lesions on magnetic resonance imaging. Among them, 86% (76/88) had a gestational age exceeding 37 weeks according to the Ballard scale, and 81% (71/88) had a birth weight exceeding 2500 g. Cohen’s d effect size was calculated to assess differences in endothelial frequency between groups, indicating a small effect size based on cerebral MRI findings (Cohen’s d values for Day 2 = 0.2351 and Day 3 = 0.2325).ConclusionNIRS represents a valuable tool for monitoring cerebral autoregulation in neonates affected by perinatal asphyxia, underscoring the utility of assessing endothelial frequency or energy on rScO2 measured by NIRS using the original INVOS™ device frequency.

Evaluation and analysis of neurocognitive dysfunction in patients with colorectal cancer after radical resection: A retrospective study.

With the continuous progress of colorectal cancer treatment technology, the survival rate of patients has improved significantly, but the problem of postoperative neurocognitive dysfunction has gradually attracted attention. To analyze the risk factors for delayed postoperative neurocognitive recovery (DNR) after laparoscopic colorectal cancer surgery and constructed a risk prediction model to provide an evidence-based reference for the prevention and treatment of DNR after laparoscopic colorectal cancer surgery. The clinical data of 227 patients with colorectal cancer who underwent laparoscopic surgery and regional cerebral saturation oxygenation (rScO2) monitoring at our hospital from March 2020 to July 2022 were retrospectively analyzed. Common factors and potential factors affecting postoperative DNR were used as analysis variables, and univariate analysis and multifactor analysis were carried out step by step to determine the predictors of the model and construct a risk prediction model. The predictive performance of the model was assessed by the receiver operating characteristic (ROC) curve, the calibration curve was used to assess the fit of the model to the data, and a nomogram was drawn. In addition, 30 patients who met the inclusion and exclusion criteria from January 2023 to July 2023 were selected for external verification of the prediction model. The incidence of postoperative DNR in the modeling group was 15.4% (35/227). Multivariate analysis revealed that age, years of education, diabetes status, and the lowest rScO2 value were the independent influencing factors of postoperative DNR (all P < 0.05). Accordingly, a DNR risk prediction model was constructed after laparoscopic colorectal cancer surgery. The area under the ROC curve of the model was 0.757 (95%CI: 0.676-0.839, P < 0.001), and the Hosmer-Lemeshow test of the calibration curve suggested that the model was well fitted (P = 0.516). The C-index for external validation of the row was 0.617. The DNR risk prediction model associated with rScO2 monitoring can be used for individualized assessment of patients undergoing laparoscopic colorectal cancer surgery and provides a clinical basis for the prevention of DNR after surgery.

Exogenous ketosis attenuates acute mountain sickness and mitigates normobaric high-altitude hypoxemia.

Acute mountain sickness (AMS) represents a considerable issue for individuals sojourning to high altitudes with systemic hypoxemia known to be intimately involved in its development. Based on recent evidence that ketone ester (KE) intake attenuates hypoxemia, we investigated whether exogenous ketosis might mitigate AMS development and to identify underlying physiological mechanisms. Fourteen healthy, male participants were enrolled in two 29h protocols (simulated altitude of 4,000-4,500m) receiving either KE or a placebo (CON) at regular timepoints throughout the protocol in a randomized, crossover manner. Physiological responses were characterized after 15min and 4h in hypoxia, and the protocol was terminated prematurely upon development of severe AMS (Lake Louise Score ≥ 10). KE ingestion induced a consistent diurnal ketosis ([ßHB] of ~3 mM), whereas blood [ßHB] remained low (<0.6 mM) in CON. Each participant tolerated the protocol equally long or longer (n=6 or n=8, resp.) in KE. Protocol duration increased by 32% on average with KE, and doubled upon KE for severe AMS-developing participants (n=9). Relative to CON, KE induced a mild metabolic acidosis, hyperventilation, and relative sympathetic dominance. KE also inhibited the progressive hypoxemia that was observed between 15min and 4h in hypoxia in CON, while concomitantly increasing cerebral oxygenation and capillary pO2 within this timeframe despite a KE-induced reduction in cerebral oxygen supply. These data indicate that exogenous ketosis attenuates AMS development. The key underlying mechanisms include improved arterial and cerebral oxygenation, in combination with lowered cerebral blood flow and oxygen delivery, and increased sympathetic dominance.

Induced blood flow oscillations at 0.1 Hz protects oxygenation of severely ischemic tissue in humans.

Generating 10-s (∼0.1 Hz) fluctuations or "oscillations" in arterial pressure and blood flow blunts reductions in cerebral tissue oxygenation in response to 15%-20% reductions in cerebral blood flow. To examine the effect of 0.1 Hz hemodynamic oscillations on tissue oxygenation during severe ischemia, we developed a partial limb ischemia protocol targeting a 70%-80% reduction in blood flow. We hypothesized that 0.1 Hz hemodynamic oscillations would attenuate reductions in tissue oxygenation during severe ischemia. Thirteen healthy humans (6 M and 7 F; 27.3 ± 4.2 yr) completed two experimental protocols separated by ≥48 h. In both conditions, an upper arm cuff was used to decrease brachial artery (BA) blood velocity by ∼70%-80% from baseline. In the oscillation condition (0.1 Hz), 0.1 Hz hemodynamic oscillations were induced by intermittently inflating and deflating bilateral thigh cuffs every 5 s during forearm ischemia. In the control condition (0 Hz), the thigh cuffs were inactive. BA blood flow, forearm tissue oxygenation (SmO2), and arterial pressure were measured continuously. The initial reduction in BA blood velocity was tightly matched between protocols (0 Hz: -76.9 ± 7.9% vs. 0.1 Hz: -75.5 ± 7.4%, P = 0.49). Although 0.1 Hz oscillations during forearm ischemia had no effect on the reduction in BA velocity (0 Hz: -73.0 ± 9.9% vs. 0.1 Hz: -73.3 ± 8.2%, P = 0.91), the reduction in SmO2 was attenuated (0 Hz: -35.7 ± 8.6% vs. 0.1 Hz: -27.2 ± 8.9%, P = 0.01). These data provide further evidence for the use of 0.1 Hz hemodynamic oscillations as a potential therapeutic intervention for conditions associated with severe tissue ischemia (e.g., hemorrhage and stroke).NEW & NOTEWORTHY We investigated the effects of induced 10-s (0.1 Hz) oscillations in blood flow on forearm tissue oxygenation during severe ischemia. Intermittent inflation of bilateral thigh cuffs was used as a clinically applicable method to drive blood flow oscillations. In support of our hypothesis, 0.1 Hz oscillations in blood flow blunted reductions in forearm tissue oxygenation. These results further support the potential use of oscillatory hemodynamics as a therapeutic intervention for ischemic conditions.

Using cerebral regional oxygen saturation and amplitude-integrated electroencephalography in neonates on extracorporeal membrane oxygenation: preliminary experience from a single center

ObjectiveThis study aims to evaluate the application value in neurological outcome of cerebral regional oxygen saturation (CrSO2) and amplitude-integrated electroencephalography (aEEG) monitoring during neonatal extracorporeal membrane oxygenation (ECMO) courses.Methods We retrospectively analyzed 18 neonates receiving veno-arterial ECMO (V-A ECMO) support at our hospital from July 2021 to December 2022. Continuous monitoring of CrSO2 and brain electrical activity was conducted using near-infrared spectroscopy (NIRS) and aEEG throughout the ECMO treatment. We collected and analyzed related clinical data.ResultsAmong the 11 survivors, 5 were categorized as the normal group (N group) and 6 as the abnormal group (AN group) based on post-ECMO brain MRI outcomes. The N group exhibited shorter time percentage of significant CrSO2 reduction (> 25% from baseline or absolute value < 40%), better fractional tissue oxygen extraction (FTOE) rates, and more stable mean percentage changes in CrSO2 compared to the AN group. Neonates in the N group predominantly showed mildly abnormal aEEG readings, with one patient displaying disrupted sleep-wake cycles. This particular patient also had more significant CrSO2 reduction and poorer FTOE compared to others in the N group. Additionally, the Test of Infant Motor Performance (TIMP) scores indicated hypoevolutism in this patient before discharge, while others in the N group had normal TIMP scores. In the AN group, 4 exhibited moderate and 2 severe aEEG abnormalities; 5 had hypoevolutism TIMP scores, and 1 with moderate aEEG abnormalities maintained a normal TIMP score, exhibiting lesser CrSO2 reduction and improved FTOE.ConclusionCrSO2 and aEEG monitoring show potential as routine assessments for neurological outcomes during neonatal ECMO. In our cohort, a tendency was observed where neonates with greater reductions in CrSO2 and more severe aEEG abnormalities experienced poorer neurological outcomes.

Usefulness of bilateral cerebral regional oxygen saturation measurements in determining selective cerebral perfusion flow rate in a pediatric patient with aortic arch stenosis: a case report

BackgroundWe report a pediatric case where bilateral regional oxygen saturation (rSO2) measurements were useful in determining the selective cerebral perfusion (SCP) flow rate.Case presentationA 9-year-old Japanese boy, 128 cm tall and weighing 25.6 kg, was scheduled for aortic arch reconstruction due to a 90–100 mmHg pressure gradient. Pediatric-sized oximetry sensors were attached to the bilateral forehead area. The rSO2 levels were 70–80% on the right and 80–90% on the left during cardiopulmonary bypass. Immediately following deep hypothermic circulatory arrest with the body temperature cooled to 25 °C, SCP was initiated from the right brachiocephalic artery at 10 mL/kg/min. As the rSO2 decreased steeply to 43–45% on the right and to 32–38% on the left, the SCP flow was increased to 15 mL/kg/min. The right rSO2 increased promptly to 50–60%, but the left rSO2 remained at 30–40%. After the SCP flow was increased to 20 mL/kg/min, bilateral rSO2 levels of 50–60% were obtained, and the SCP flow rate was maintained. The patient was transferred to the ICU postoperatively and extubated on the second postoperative day with no neurological abnormalities.ConclusionsBilateral rSO2 measurements are essential even for a pediatric patient undergoing SCP, despite the limited forehead area.

Effect of upper body venoarterial ECMO on systemic hemodynamics and oxygenation: A computational study

BackgroundThis study seeks to quantify the effects of upper body veno-arterial extracorporeal membrane oxygenation (VA ECMO) on the anatomical distribution of oxygen delivery in the setting of hypoxic respiratory failure and provide new insights that will guide clinical use of this support strategy to bridge patients to lung transplant. MethodsEmploying a patient-specific vascular geometry and a quantitative model of oxygen transport, computational simulations were performed to determine hemodynamics and oxygen delivery in the ascending and descending aorta, left and right coronary arteries, and great vessels during upper body VA ECMO support. Oxygen content in ECMO circuit blood flow was varied while considering different degrees of lung failure severity. Using lumped parameter models to dynamically apply perfusion boundary conditions, hemodynamic parameters and oxygen content were analyzed to assess the effect of ECMO supply titration. ResultsThe results emphasize the importance of anatomical distribution for tissue oxygen delivery in severe lung failure, with ECMO-derived flow primarily augmenting oxygen content in specific vascular beds. They also demonstrate that although cannulating the subclavian artery can enhance cerebral oxygen delivery, its ability to ensure sufficient oxygen delivery to the coronary circulation seems to be comparatively restricted. ConclusionsThe oxygen delivery to a specific vascular area is primarily determined by the oxygen content in the source of perfusion. Caution is advised with upper body VA ECMO for patients with hypoxic respiratory failure and right ventricle dysfunction, due to potential coronary ischemia. Management of these patients is challenging due to disease progression and organ availability uncertainties.

Acute Sleep Deprivation and Cerebral and Skeletal Muscle Oxygenation: A Review and Future Directions

Cerebral and skeletal muscle oxygenation are critical research areas for understanding blood flow and oxygen delivery during various physiological states, including cognitive tasks and exercise. Measuring oxygenated and deoxygenated hemoglobin through functional near-infrared spectrometry (fNIRS) enables non-invasive assessment of cerebral and skeletal muscle oxygenation. Research using fNIRS to explore oxygenation after sleep deprivation (SD) is limited and often contradictory. We reviewed how SD affects cerebral and muscle oxygenation as part of a broader review of how SD affects exercise through altered physiologic and perceptual responses. Herein, we consolidate existing knowledge, identify gaps, and suggest directions for future investigation. A comprehensive literature review was conducted via predefined search parameters using PubMed and Google Scholar, focusing on studies that employed fNIRS to measure cerebral and/or skeletal muscle oxygenation in humans after SD (total or partial) or in individuals with chronically fragmented sleep due to obstructive sleep apnea (OSA). Select studies report increased cerebral oxygenation post-SD, potentially due to compensatory mechanisms and increased brain activity. Contrarily, several studies indicate decreased cerebral oxygenation following SD, potentially due to impaired endothelial function, cortical neurovascular coupling, suppressed brain activity, or decreased oxygen consumption. Cerebral oxygenation may be associated with perceived exertion, suggesting meaningful links to exercise. Interestingly, exercise training may mitigate the effects of SD on oxygenation. The only study investigating skeletal muscle oxygenation with regards to sleep status found a lower tissue saturation index in OSA participants compared to controls, though hemoglobin parameters did not differ. The effect of SD on oxygenation remains equivocal, with no studies fully elucidating the mechanisms underlying these changes. This review is the foundation for an ongoing prospective study investigating the impact of acute SD on exercise capacity and fNIRS-derived cerebral and skeletal muscle oxygenation, with two participants enrolled to date and interim analyses planned at n=5 participants.

Cerebral hypoperfusion resulting from improper cannulation positioning during aortic dissection surgery: a case report

BackgroundSelective antegrade cerebral perfusion (sACP) is a crucial cerebral protection technique employed during aortic dissection surgeries involving cardiopulmonary bypass. However, postoperative neurological complications, particularly those related to cannulation issues and perfusion problems, remain a significant concern.Case PresentationThis case report details an unusual instance where a 38-year-old male patient with Marfan syndrome experienced cerebral hypoperfusion during emergency surgery for Stanford Type A aortic dissection. Despite following standard protocols, a significant drop in regional cerebral oxygen saturation (rSO2) and abnormal blood pressure fluctuations were observed shortly after initiating sACP via the innominate artery. After initial attempts to optimize perfusion flow proved ineffective, the cannulation position was adjusted, leading to improvements. Nevertheless, the patient subsequently exhibited signs of cerebral hypoperfusion and was found to have suffered a new cerebral infarction.ConclusionsThis case report underscores the importance of precise cannula placement during sACP procedures and the dire consequences that can arise from improper positioning. It emphasizes the need for continuous monitoring and prompt intervention in cases of abnormal cerebral oxygenation and blood pressure, as well as the value of considering cannulation-related issues as potential causes of postoperative neurological complications.

Impact of Manual Sustained Inflation vs Stepwise PEEP on Pulmonary and Cerebral Outcomes in Carotid Endarterectomy Patients.

BACKGROUND Recruitment maneuvers (RMs) are used to reduce pulmonary atelectasis in patients under general anesthesia, but they can lead to a decrease in cerebral hemodynamics. MATERIAL AND METHODS Thirty patients undergoing carotid endarterectomy were randomized to a manual sustained inflation (SI) group or a stepwise increase in PEEP (IP) group. During both RMs, the peak airway pressure (Ppeak) was maintained at 30 cmH₂O for 30 s. Electrical impedance tomography was used to evaluate pulmonary aeration changes. Mean velocity of blood flow in the middle cerebral artery (Vm) and cerebral oxygen saturation (rScO₂) was monitored intraoperatively. RESULTS IP improved lung aeration better at Ppeak=30 cmH₂O than SI (58.2±8.4% vs 46.0±8.3%, P=0.001) and this persisted until the end of surgery. Dorsal (dependent) ventilation 30 min after extubation in the SI group was lower than that before surgery (7.7±2.6% vs 9.9±3.8%, P=0.003). Vm and rScO₂ returned to baseline immediately after RM in the SI group, while it remained below baseline in the IP group (42.5±12.6 vs 50.9±18.8 cm/s, P<0.001 and 68.1±3.5% vs 70.6±3.7%, P=0.001). Heart rate declined significantly during RM only in the SI group (55.9±6.6 vs 52.2±6.9 bpm, P=0.008). CONCLUSIONS Compared with SI, IP performed better in improving lung aeration, with greater hemodynamic stability. IP resulted in slower recovery of cerebral blood flow and oxygenation.

Cerebral oximetry in high-risk surgical patients: where are we?

This review aims to summarize the latest evidence on the role of near-infrared spectroscopy (NIRS) in monitoring cerebral oxygenation in high-risk surgical patients, including both cardiac and noncardiac surgeries, and to present a new algorithm for its application. NIRS effectively measures brain oxygen saturation noninvasively, proving valuable in cardiac surgeries to reduce neurological complications, though its impact on nonneurological outcomes is less clear. In noncardiac surgeries, NIRS can help prevent complications like postoperative cognitive dysfunction, particularly in high-risk and major surgeries. Studies highlight the variability of cerebral oxygenation impacts based on surgical positions, with mixed results in positions like the beach chair and sitting positions. A structured algorithm for managing cerebral desaturation has been proposed to optimize outcomes by addressing multiple factors contributing to blood oxygen content and delivery. Despite its limitations, including spatial resolution and interindividual variability, NIRS is a useful tool for intraoperative cerebral monitoring. Further studies are needed to confirm its broader applicability in noncardiac surgeries, but current evidence supports its role in reducing postoperative complications especially in cardiac surgeries.

The association of acute and chronic phase cerebrovascular reactivity with patient reported quality of life following moderate-to-severe traumatic brain injury

Global outcomes have been reported to be associated with cerebrovascular reactivity (CVR) in the acute phase following moderate and severe traumatic brain injury (TBI). The association of CVR in the acute and chronic phase of injury with patient-reported health-related quality of life metrics (HRQOL) metrics has never been explored. The aim of this study is to examine the association of CVR, as measured by the cerebral oxygen indices (COx and COx_a), in the acute and chronic phase following moderate and severe TBI, with patient reported HRQOL. In this prospective cohort study, performed in a Canadian quaternary care center, the association between continuous acute and chronic phase CVR with patient reported HRQOL outcomes following moderate and severe TBI was examined. The main outcomes of interest of this study were validated measures of patient-reported HRQOL over various domains as measured by both the 12-Item Short-Form Health Survey (SF-12) and a Quality of Life after Brain Injury (QOLIBRI) questionnaire. In the 29 subjects of this cohort, acute phase CVR was found to be significantly more active in those with a favorable Mental Component Summary (MCS) scores of the SF-12 at early follow-up when measured by COx (-0.015 [IQR: -0.067 to 0.032] vs 0.040 [IQR: 0.019 to 0.137] for Favorable first MCS vs Unfavorable respectively; Mann–Whitney U test p-value = 0.046) and COx_a (0.038 [IQR: 0.009 to 0.062] vs 0.112 [IQR: 0.065 to 0.167] for Favorable first MCS vs Unfavorable respectively; Mann–Whitney U test p-value = 0.014). Further, multivariable logistic regression analysis found acute phase COx and COx_a to improve model performance when predicting favorable versus unfavorable early MCS scores over established parameters such as age and measures of injury severity. Associations between outcomes and chronic phase CVR were limited, potentially due to short recording periods. This is the first ever pilot study to identify a relationship between acute phase CVR following moderate-to-severe TBI with mental and cognitive outcomes as experienced by patients. Given the small cohort, these findings will need to be confirmed in a larger multicenter study. This highlights the need for additional examination of the role dysfunctional CVR may play in mental and cognitive outcomes, as well as patient-reported outcomes more generally following TBI.

Sevoflurane in the Acute Phase of Severe Traumatic Brain Injury

The aim of the study was to evaluate the usefulness and safety of sevoflurane in patients in the acute phase of severe traumatic brain injury (TBI).Materials and methods. A prospective, randomized, pilot clinical trial was conducted at the Sklifosovsky Research Institute for Emergency Medicine (Moscow) in adults with acute severe TBI, aged 18 years and older, undergoing intensive intracranial pressure (ICP)-guided therapy. To achieve the desired sedative effect, the inhaled anesthetic sevoflurane was administered in the main group, and standard doses of intravenous propofol were administered in the control group. ICP and cerebral oxygen extraction fraction (OEF) were monitored in all patients. Hemodynamic and respiratory support parameters, transcranial Doppler ultrasound scan, brain bioelectrical activity, brain CT scan, laboratory parameters, markers of inflammation, patients' need for sedation and mechanical ventilation, and length of ICU stay were also evaluated.Results. The use of inhalation sedation contributed to the reduction of ICP on day 2 (9.5 mmHg in the sevoflurane group and 17.3 mmHg in the propofol group, P=0.003) and day 3 (10 mmHg and 14.2 mmHg, respectively, P=0.005). BIS monitoring showed no significant difference in depth of sedation between groups on day 2 (60 vs. 48.5, P=0.070) and day 3 (61 vs. 46, P=0.095). Inhalation sedation reduced cerebral OEF on the injury side compared to propofol on day 2 (23.3 vs. 30.2%, P=0.006) and day 3 (22.7 vs. 31.2%, P&lt;0.001). After 24 hours of sedation therapy, there was a significant difference in P/F (PaO₂/FiO₂) ratios between the groups. On days 1, 3, and 7, the sevoflurane group had P/F ratios of 340, 324, and 323 mmHg, while the propofol group had significantly lower ratios of 271, 278, and 275 mmHg (P&lt;0.001). Pneumonia was documented in 9 cases in the sevoflurane group vs. 18 cases in the propofol group (P=0.028), and a similar trend was observed in the total number of infectious complications: 13 vs. 21 cases, respectively (P=0.046).Conclusion. Sevoflurane in the acute phase of severe TBI was not only safe, but also improved several vital functions, including ICP, blood pressure, P/F ratio, and also slowed brain metabolism via reduced oxygen consumption without affecting the depth of sedation according to BIS monitoring data. All of the above suggests that inhalation sedation may improve the prognosis for patient recovery. However, multicenter randomized clinical trials are needed to identify and verify all positive and negative effects of inhalation sedation in this patient population.

Effects of Prostaglandin E1 and Balloon Atrial Septostomy on Cerebral Blood Flow and Oxygenation in Newborns Diagnosed with Transposition of the Great Arteries.

Dextro-transposition of the great arteries (D-TGA) is a critical congenital heart defect that can impact neurodevelopment due to cerebral perfusion and oxygenation disorders followed by alterations in synaptogenesis, gyrification, sulcation, and the microstructure. Brain injuries can occur both pre-operatively and postoperatively, especially white matter injuries, neuronal loss, and stroke. Materials and Methods: In a retrospective study conducted at a tertiary center between 2016 and 2023, we investigated the early effects of Prostaglandin E1 (PGE1) administration and balloon atrial septostomy (BAS) on cerebral blood flow and oxygenation in inborn neonates with D-TGA. Cerebral Doppler Ultrasound in the anterior cerebral artery (ACA) was performed to assess the resistive index (RI), Peak Systolic Velocity (PSV), and End-Diastolic Velocity (EVD) before PGE1, before the BAS procedure, and 24 h after birth. Cerebral regional saturations of oxygen (crSO2) and cerebral fractional tissue oxygen extraction (cFTOE) were evaluated. D-TGA patients were divided into the PGE1 group and the PGE1 + BAS group. Age-matched healthy controls were used for comparison. Results: All 83 D-TGA newborns received PGE1 within two hours after delivery, of whom 46 (55.42%) underwent BAS. In addition, 77 newborns composed the control group. PGE1 administration increased crSO2 from 47% to 50% in the PGE1 group, but lower than in controls at 24 h of life, while cFTOE remained elevated. The RI increased 24 h after delivery (0.718 vs. 0.769; p = 0.000002) due to decreased EDV (10.71 vs. 8.74; p < 0.0001) following PGE1 treatment. The BAS procedure resulted in a significant increase in crSO2 from 42% to 51% at 24 h of life in the PGE1 + BAS group. Doppler parameters exhibited a similar trend as observed in the PGE1 group. Conclusions: PGE1 treatment and BAS are lifesaving interventions that may improve cerebral perfusion and oxygenation in newborns with D-TGA during the transition period, as reflected by increasing SpO2 and crSO2.

Individualized cortical gyrification in neonates with congenital heart disease.

Congenital heart disease is associated with impaired early brain development and adverse neurodevelopmental outcomes. This study investigated how individualized measures of preoperative cortical gyrification index differ in 142 infants with congenital heart disease, using a normative modelling approach with reference data from 320 typically developing infants. Gyrification index Z-scores for the whole brain and six major cortical areas were generated using two different normative models: one accounting for post-menstrual age at scan, post-natal age at scan and sex, and another additionally accounting for supratentorial brain volume. These Z-scores were compared between congenital heart disease and control groups to test the hypothesis that cortical folding in infants with congenital heart disease deviates from the normal developmental trajectory. The relationships between whole-brain gyrification index Z-scores from the two normative models and both cerebral oxygen delivery and neurodevelopmental outcomes were also investigated. Global and regional brain gyrification was significantly reduced in neonates with congenital heart disease, but not when supratentorial brain volume was accounted for. This finding suggests that whilst cortical folding is reduced in congenital heart disease, it is primarily driven by a reduction in brain size. There was a significant positive correlation between cerebral oxygen delivery and whole-brain gyrification index Z-scores in congenital heart disease, but not when supratentorial brain volume was accounted for. Cerebral oxygen delivery is therefore likely to play a more important role in the biological processes underlying volumetric brain growth than cortical folding. No significant associations between whole-brain gyrification index Z-scores and motor/cognitive outcomes or autism traits were identified in the 70 infants with congenital heart disease who underwent neurodevelopmental assessment at 22-months. Our results suggest that chronic in utero and early post-natal hypoxia in congenital heart disease is associated with reductions in cortical folding that are proportional to reductions in supratentorial brain volume.

Optimizing RBC Transfusion Strategies in Traumatic Brain Injury: Insights on Early Resuscitation and Cerebral Oxygenation.

Effective early resuscitation and maintenance of brain oxygenation are critical for improving the outcomes of patients with severe traumatic brain injury (TBI). Red blood cell (RBC) transfusion plays a vital role in this process. Although RBC transfusion can enhance cerebral oxygenation and stabilize hemodynamics, it also poses significant risks including transfusion-related lung injury and transfusion-associated circulatory overload, highlighting the importance of meticulous transfusion management. This review explores transfusion strategies during the early resuscitation phase and the management of anemia in patients with severe TBI, focusing on appropriate treatment targets, utilizing monitoring-based personalized approaches, and summarizing recent research and current insights.

Cerebral oxygenation in preterm infants at high altitude: a prospective pilot cohort study

Cerebral oxygenation in preterm infants at high altitude: a prospective pilot cohort study