Search Results (115)

Background: Intracranial pressure (ICP) monitoring remains the cornerstone of neurocritical care in severe traumatic brain injury (TBI), yet its prognostic value as a standalone metric is limited. The Pressure Reactivity Index (PRx), a continuous measure of cerebrovascular reactivity derived from ICP and arterial blood pressure, may offer additional or complementary prognostic information. This systematic review aimed to compare the prognostic performance of PRx-derived metrics versus standard ICP monitoring for mortality and functional outcome in patients with TBI. Methods: A systematic search of PubMed, Web of Science, and Scopus was conducted for studies published between January 2000 and December 2025. Studies were eligible if they included adult TBI patients with continuous multimodal monitoring and reported comparative prognostic data for PRx- and ICP-based metrics. Risk of bias within the studies was appraised via the QUIPS tool, and the GRADE system was used to rate the strength of the evidence. Due to methodological heterogeneity, findings were synthesized narratively. Results: Nine studies were included. Applying a maximum-cohort estimation to account for overlapping registries, the pooled sample comprised a minimum of 1240 unique patients. In the majority of included studies, direct within-cohort head-to-head comparisons demonstrated that specific PRx-derived metrics—such as the individualized ICP threshold (iICP), Longest Continuous Duration of Autoregulatory Impairment (LCAI), Lower Limit of Reactivity (LLR), and time-integrated burdens (%Time > Threshold)—yielded stronger prognostic discrimination compared to standard ICP thresholds for both mortality (PRx: AUC 0.747–0.648 and ICP: AUC 0.660–0.614) and functional outcome. When added to established predictive models, PRx-derived metrics provided clinically meaningful incremental improvements in prognostic accuracy, with descriptive incremental AUC gains ranging from +0.039 to +0.170 across the six studies reporting model augmentation. Due to heterogeneity in baseline models, PRx-derived metrics, and patient populations, these findings are presented strictly as a descriptive range. Conclusions: PRx and PRx-derived cerebrovascular reactivity metrics-namely iICP, LCAI, LLR, and time-integrated burdens of autoregulatory failure—show potential to offer additive prognostic value beyond standard ICP monitoring in severe TBI. However, because current evidence is strictly observational and likely influenced by institutional confounders, it cannot currently support definitive clinical recommendations. Further prospective, multicenter studies utilizing standardized thresholds are necessary to confirm these associative findings and isolate their true prognostic value. Full article

Background and Objectives: This prospective, randomized study aimed to evaluate the effects of different local anesthetic (LA) volume–dose combinations administered during supraclavicular brachial plexus block (SCBPB), a widely used technique in upper extremity surgery. These effects were assessed by analyzing changes in the ratios of optic nerve sheath diameter (ONSD) to eyeball transverse diameter (ETD), obtained by ultrasound (US) and considered indirect measures of intracranial pressure (ICP). Materials and Methods: Sixty four ASA I–II patients aged 18–50 years undergoing upper extremity surgery were randomized into four groups receiving 15 mL (Group A), 20 mL (Group B), 25 mL (Group C), or 30 mL (Group D) of LA (equal volumes of 0.5% bupivacaine and 2% prilocaine). ONSD/ETD ratios were measured bilaterally at baseline, 20, and 60 min. Perfusion index (PI), end-tidal carbon dioxide (EtCO₂), block onset times and block duration were also assessed. Results: Groups C and D showed significant bilateral increases in both ONSDint/ETD and ONSDext/ETD ratios at 20 and 60 min compared with baseline (p < 0.05). Group B demonstrated a significant increase only in the ONSDext/ETD ratio on the block side, whereas Group A showed no significant change. PI increased earlier and more markedly with increasing LA volume–dose. No significant intergroup differences were observed in EtCO₂. In pairwise comparisons, sensory block onset was significantly longer in Group A than in Groups B, C, and D (p < 0.001). Motor block onset was significantly longer in Group A than in Groups C and D, and in Group B than in Group D (p < 0.001). Analgesia duration was significantly shorter in Group A than in Groups B, C, and D, and in Group B than in Groups C and D (p < 0.001). Conclusions: Increasing the LA volume–dose in US-guided SCBPB accelerates sensory and motor block onset and significantly prolongs block duration. A volume-dependent increase in ONSD/ETD ratios was observed on both the blocked and contralateral sides. PI showed an early and marked increase, particularly in high-volume–dose administrations, reflecting block success. Non-invasive EtCO₂ monitoring did not detect significant changes. Full article

Background: Intracranial hypertension is a critical complication of acute intracerebral hemorrhage (ICH), contributing to high early mortality and poor functional outcomes. Invasive intracranial pressure (ICP) monitoring remains the gold standard but carries procedural risks and is resource-intensive. This study evaluated the diagnostic and prognostic utility of optic nerve sheath diameter (ONSD) ultrasonography and transcranial Doppler (TCD)-derived pulsatility index (PI) as non-invasive ICP surrogates in patients with severe ICH. Methods: A prospective observational study was conducted in 42 patients with acute ICH who underwent concurrent invasive ICP monitoring and serial ONSD/PI measurements at 10 time points (T0–T9) between October 2021 and August 2024. Diagnostic performance was assessed using measurement-level receiver operating characteristic (ROC) curve analysis. Exploratory early mortality prediction was evaluated using random forest machine learning models incorporating ONSD, PI, age, and sex. Results: A total of 274 paired ONSD–PI–ICP measurements were obtained. Both ONSD and PI showed moderate positive correlations with invasive ICP (rho = 0.49 and 0.43, respectively; p < 0.001). ONSD demonstrated superior diagnostic accuracy for detecting ICP ≥ 20 mmHg (AUC = 0.83; optimal threshold: 5.88 mm; sensitivity: 81%; specificity: 82%) compared to PI (AUC = 0.75). In exploratory random forest analyses, the combined ONSD–PI model showed high apparent discrimination for elevated ICP detection (AUC = 0.98), while the model incorporating ONSD, PI, age, and sex showed promising but potentially optimistic discrimination for early mortality prediction (AUC = 0.95). These machine learning results should be interpreted cautiously because of the small sample size, repeated-measurement structure, measurement-level data partitioning, and limited number of early deaths. Conclusions: ONSD ultrasonography and TCD-derived PI showed promising performance as non-invasive ICP markers in severe acute ICH. However, because of the small sample size, repeated-measurement design, measurement-level analyses, and exploratory nature of the machine learning models, these findings require validation in larger external cohorts before routine clinical implementation. Full article

Background: Raised intracranial pressure in intracranial tumor surgery is driven by mass effect and edema, but invasive monitoring is selectively used, and imaging may not fully reflect contemporaneous pressure. We performed a pilot evaluation of preoperative optic nerve sheath diameter and CT mass effect in relation to pre-excision invasive intracranial pressure. Methods: This retrospective pilot study included adults with available preoperative optic nerve sheath diameter, CT mass effect graded by the Gordon–Firing score, and recorded pre-excision invasive intracranial pressure. The primary analysis assessed association with continuous pre-excision intracranial pressure using correlation and linear regression. Perioperative change in invasive intracranial pressure and serial optic nerve sheath diameter were also analyzed. Threshold analyses were exploratory. Results: In total, 45 patients were included. Mean pre-excision intracranial pressure was 29.40 mmHg, and 39/45 (86.7%) had intracranial pressure > 20 mmHg. Optic nerve sheath diameter showed a modest association with pre-excision intracranial pressure (r = 0.279, p = 0.064), whereas Gordon–Firing showed a stronger association (r = 0.522, p < 0.001). In the combined model, Gordon–Firing remained associated with intracranial pressure, whereas optic nerve sheath diameter did not. Mean intracranial pressure decreased by 12.24 mmHg after tumor excision, and optic nerve sheath diameter decreased at 1 h and 6 h postoperatively. Conclusions: CT mass effect graded by Gordon–Firing showed a stronger cross-sectional relationship with pre-excision invasive intracranial pressure than optic nerve sheath diameter, whereas serial optic nerve sheath diameter appeared more useful as a perioperative marker. Full article

Background: The photopic negative response (PhNR) of the full-field electroretinogram is a retinal ganglion cell-weighted functional signal increasingly proposed as a clinical biomarker. Despite extensive study across ocular and systemic diseases, its precise clinical role and incremental value remain incompletely established. Methods: This narrative review synthesizes key human studies of the photopic negative response, with emphasis on physiological basis, recording methodology, and clinical contexts in which PhNR may provide added functional insight. Results: In glaucoma, PhNR provides an objective measure of retinal ganglion cell dysfunction that correlates moderately with optical coherence tomography (OCT)-derived structural loss and visual field indices, but with substantial inter-individual variability. Its greatest clinical utility lies in early disease detection, cross-sectional functional assessment, and documenting short-term functional changes following intraocular pressure reduction, rather than longitudinal progression monitoring. Beyond glaucoma, PhNR reveals inner retinal dysfunction in systemic and genetic conditions, particularly idiopathic intracranial hypertension and diabetes, where retinal ganglion cells may reflect broader neurological or metabolic stress. Conclusions: PhNR is best viewed not as a standalone diagnostic or progression tool, but as a complementary functional biomarker that adds objective insight when structural imaging or psychophysical testing is limited or discordant. Its role aligns closely with the retina’s emerging function as a mirror of systemic and genetic disease, provided recordings are standardized and results interpreted cautiously. Full article

Background and Clinical Significance: Decompressive hemicraniectomy (DHC) is a life-saving intervention for malignant middle cerebral artery (MCA) infarction, but postoperative secondary injury mechanisms and functional outcome remain difficult to evaluate using intracranial pressure (ICP) alone. The pressure reactivity index (PRx), calculated as the moving correlation coefficient between ICP and mean arterial pressure (MAP), provides a measure of cerebral autoregulation. The utility of PRx monitoring in ischemic stroke, especially following DHC, remains uncertain. Case Presentation: We describe two patients presenting with acute ischemic stroke in the MCA territory who underwent DHC followed by postoperative ICP and PRx monitoring. Case 1 is a 40-year-old female with a left proximal MCA occlusion initially treated with endovascular thrombectomy (EVT) who required emergent DHC due to re-occlusion. Postoperatively, ICPs remained controlled, and PRx values were favorable (<0.2), indicating preserved cerebral autoregulation. She later showed moderate neurological improvement. Case 2 was a 68-year-old female with a left proximal MCA occlusion treated with EVT who developed worsening cerebral edema and midline shift, necessitating emergent DHC. Despite adequate ICP control, PRx values remained markedly elevated (0.45 to 0.73), consistent with impaired cerebral autoregulation, and her neurologic state remained poor at discharge. Conclusions: These contrasting cases suggest that PRx may provide physiologic information not reflected by ICP metrics alone post-DHC. PRx monitoring may provide complementary physiologic insight into postoperative autoregulatory status following DHC. Further investigation is warranted to define its role in individualized post-DHC management and prognostication in malignant ischemic stroke. Full article

Flexible and biocompatible sensors are vital for a wide range of biomedical applications, including real-time health monitoring, intracranial pressure monitoring, knee replacement surgeries, wearables, and smart prosthetics. While various highly sensitive and stable pressure sensors have been demonstrated, they often lack the conformability and biocompatibility crucial for their wider application in various bio-integrated electronic systems. Herein, a piezoelectric pressure sensor is proposed using a hybrid polymer composite by leveraging the unique properties of Chitosan and Parylene C. Various material characterisations, such as XRD and FTIR, were performed to reveal structural and chemical characteristics of the novel composite material. Next, electromechanical characterisations of the pressure sensor were performed to reveal its dynamic sensing properties. The pressure sensor exhibits excellent sensitivity for both pressure and frequency, as well as cyclic stability (10³ cycles), wide pressure range (20–70 kPa), and biocompatibility. Full article

Monitoring intracranial pressure (ICP) dynamics is critical for the management of traumatic brain injury, stroke, other neurosurgical conditions, and cerebral blood flow autoregulation; however, invasive ICP monitoring carries risks such as infection, hemorrhage, and sensor zero drift. Increasing evidence suggests that ICP waveform morphology provides clinically relevant information beyond mean ICP value alone. In this first-in-human prospective comparative clinical study, we evaluated the feasibility and accuracy of a novel, fully passive, non-invasive ICP pulse waveform monitoring system (Archimedes 02) based on the detection of eyeball mechanical movement. Fifteen intensive care unit patients (6 males, 9 females; mean age 57.1 ± 18.8 years) with clinically indicated invasive ICP monitoring or external ventricular drainage were enrolled. Three-minute monitoring sessions were performed to simultaneously acquire non-invasive ICP pulse waveforms, invasive ICP waveforms, and invasive radial artery blood pressure (ABP) waveforms. Averaged waveforms were derived for each patient and compared graphically and using correlation analysis. Non-invasive ICP pulse waves recorded with Archimedes 02 showed a strong correlation with invasive ICP waveforms ($\overline{\mathrm{R}}$ = 0.965). In contrast, correlations between non-invasive ICP and ABP waveforms ($\overline{\mathrm{R}}$ = 0.699), as well as between invasive ICP and ABP waveforms ($\overline{\mathrm{R}}$ = 0.749), were lower. These findings indicate that the non-invasive signal primarily reflects ICP dynamics rather than arterial blood pressure. This novel non-invasive ICP monitoring approach has the potential to enhance neurocritical care, particularly in settings where invasive monitoring is impractical or unavailable. Further validation in larger and more diverse patient populations is warranted. Full article

Point-of-care ultrasonography (POCUS) has become an integral part of intensive and emergency care. Despite the widespread use and availability of multipurpose ultrasound devices, the regular assessment of intracranial circulatory conditions has not become a part of daily routine in multidisciplinary intensive care units. This brief narrative review aims to summarize the fundamental knowledge about the transcranial Doppler technique and the most significant clinical areas in which the method can provide valuable assistance in daily diagnostic and therapeutic decision-making. The authors searched the PubMed database for reviews, systematic reviews, and meta-analyses using the keywords “transcranial Doppler sonography; critical care; cerebral vasospasm; brain death diagnosis; non-invasive intracranial pressure monitoring”. We conclude that TCD is a simple, yet skilled, bedside method for assessing intracranial circulation. In everyday practice, it can be used to support clinical decision-making primarily in the areas of intracranial pressure monitoring, diagnosis and follow-up of cerebral vasospasm, and diagnosis of cerebral circulatory arrest. The study of cerebral hemodynamics should be an integral part of the increasingly widespread bedside ultrasound diagnostics in intensive care. Full article

Accurate monitoring of intracranial pressure (ICP) is critical for the diagnosis and management of neurological disorders. Although various ICP sensors have been developed, their sensitivity is often limited, restricting their ability to detect subtle pressure variations. Therefore, there is a pressing need to develop ICP sensors with enhanced sensitivity to improve measurement accuracy and patient outcomes. In this paper, a highly sensitive and precise pressure sensor for intracranial pressure (ICP) monitoring was proposed. Theoretically, the beam-membrane-island structure was introduced and optimized to improve sensitivity and linearity compared to a flat membrane structure. The notches etched at beam end were designed for further improving sensitivity. Experimentally, the designed sensor achieved a sensitivity of 1.59 mV/V//kPa and a nonlinearity of −0.22% F.S. Additionally, the sensor can detect pressure with centimeter water column (cm H₂O) resolution, making it suitable for ICP monitoring. This technology holds broad application prospects in the field of medical devices. Full article

Cardiac disturbances are well-recognized in traumatic brain injury (TBI), but most involve supraventricular arrhythmias or repolarization abnormalities, while sinus arrest is rarely reported. We present a case of a 37-year-old man who developed recurrent, prolonged sinus arrest following severe TBI. He arrived intubated for airway protection after an assault, and imaging demonstrated an acute, depressed, comminuted right temporoparietal skull fracture scattered subarachnoid hemorrhage, and bilateral humeral head fractures with posterior shoulder subluxation. After craniotomy and placement of an external ventricular drain (EVD) for intracranial pressure (ICP) monitoring, the patient experienced multiple spontaneous sinus arrest episodes lasting up to 15 s despite normal metabolic, electrolyte, and toxicology evaluations. A transvenous pacemaker (TVP) was inserted to maintain adequate cardiac output and cerebral perfusion. As ICP improved, the sinus arrests resolved and the TVP was removed. This case highlights a rare neurocardiac manifestation of TBI, demonstrating that elevated ICP can precipitate profound conduction disturbances that may require temporary pacing to manage hemodynamics and prevent secondary brain injury. Full article

Background/Objectives: Postoperative intracerebral hematomas (POHs) are a common complication following brain tumor surgery and are typically associated with unfavorable outcomes. While extensive hemorrhages have been studied extensively, smaller, Non-Space-Occupying hemorrhages are frequently detected, yet their clinical relevance and associated risk factors remain insufficiently understood. This study aimed to identify predictive factors for the occurrence of Non-Space-Occupying postoperative cerebral hemorrhages in patients undergoing brain tumor resection. Methods: A total of 1481 patients without a history of anticoagulant or antiplatelet therapy underwent brain tumor surgery at our neurosurgical institute over a ten-year period. Non-Space-Occupying postoperative hemorrhages were diagnosed in 84 patients using cranial computed tomography (cCT) or magnetic resonance imaging (cMRI) performed after the tumor resection. Demographic data, pre-existing comorbidities, and tumor characteristics were collected and analyzed. Results: Non-Space-Occupying POHs occurred in 5.6% of patients. The most frequent tumor type associated with POHs was glioblastoma multiforme (N = 33; 39.3%), followed by metastatic lesions (N = 9; 10.7%) and benign primary intracranial neoplasms (N = 31; 38%). None of the affected patients exhibited new neurological deficits or signs of increased intracranial pressure. A multivariate analysis identified the tumor size as an independent risk factor for Non-Space-Occupying POHs (p = 0.002), with patient age emerging as the strongest predictor (p = 0.001). Conclusions: Non-Space-Occupying POHs after a brain tumor resection are significantly associated with the tumor size, an advanced patient age, and the presence of pre-existing liver disease. The recognition of these risk factors may facilitate targeted perioperative monitoring and guide postoperative management strategies. Full article

In recent years, Transcranial Color Doppler (TCCD) has gained increasing recognition as a non-invasive neuromonitoring tool. However, there remains a strong tendency to view arterial TCCD as the ‘stethoscope for the brain,’ while the assessment of cerebral venous flow is still underrepresented in clinical protocols. This review aims to explore the emerging role of venous TCCD, particularly when combined with Internal Jugular Vein (IJV) ultrasound, in evaluating cerebral venous outflow in both critically ill and surgical patients. We conducted a narrative review of e-Pub articles from PubMed, MEDLINE, and Scopus, on the pathophysiological factors that impair cerebral venous drainage and their clinical implications in surgical and critical care settings. Based on this evidence, we developed two procedural algorithms that integrate established knowledge of cerebral venous hemodynamics with common clinical conditions affecting venous outflow, including internal jugular central venous catheter placement, mechanical ventilation, and pneumoperitoneum. The algorithms emphasize systematic monitoring of cerebral venous drainage, including assessment of internal jugular vein morphology and Rosenthal’s vein flow, to guide procedural optimization and minimize potential neurological complications. They were informed by validated frameworks, such as the RaCeVa protocol, and are illustrated through two representative clinical case scenarios. Cerebral venous congestion can be induced by multiple established risk factors, including mechanical ventilation, cardiovascular disease, elevated intra-abdominal pressure, the Trendelenburg position, and central venous catheterization. In selected patients, real-time venous TCCD monitoring, combined with IJV assessment, allows early detection of cerebral venous outflow impairment and guides timely hemodynamic and procedural adjustments in both surgical settings and critical care contexts. Venous TCCD neuromonitoring may help prevent intracranial hypertension and its consequent neurological complications. It can guide clinical decisions during procedures that may compromise cerebral venous drainage, such as mechanical ventilation, the placement of large-bore central venous catheters, or laparoscopic and robot-assisted surgeries. Further studies are warranted to validate this strategy and better define its role in specific high-risk clinical scenarios. Full article

Stroke is the second-largest cause of death and disability worldwide, and many patients require intensive care for airway compromise, hemodynamic instability, cerebral edema, or systemic complications. This review summarizes key aspects of ICU management in both acute ischemic stroke (AIS) and hemorrhagic stroke (HS). Priorities are airway protection, oxygenation, individualized blood pressure targets, and strict control of temperature and glucose. Neurological monitoring and prompt management of intracranial pressure (ICP), together with timely surgical interventions (hemicraniectomy or hematoma evacuation), are central to acute care. Seizures are treated promptly, while routine prophylaxis is not recommended. Prevention of aspiration pneumonia, venous thromboembolism, infections, and other intensive care unit (ICU) complications is essential, along with early nutrition, mobilization, and rehabilitation. Prognosis and decisions about intensity of care require shared discussions with families and involvement of palliative services, when appropriate. Many practices remain based on observational data or extrapolation from other populations, underlining the need for stroke-specific clinical trials. Outcomes are consistently better when patients are managed in specialized stroke or neurocritical care units with a multidisciplinary treatment approach Full article

Background: Severe traumatic brain injury (TBI) often leads to elevated intracranial pressure (ICP) that requires aggressive management. Inducing burst suppression with deep sedation is an established therapy for refractory intracranial hypertension. Traditionally, barbiturate coma has been used to achieve burst-suppression EEG in TBI patients, but alternative sedative agents (propofol, midazolam, ketamine, dexmedetomidine) are increasingly utilized in modern neurocritical care. This review compares barbiturates with these alternatives for inducing burst suppression in adult TBI, focusing on protocols, mechanisms, efficacy in controlling ICP, safety profiles, and impacts on neurological outcomes. Methods: A search of the literature was performed, including clinical trials, observational studies, and guidelines on deep sedation for ICP control in adult TBI. Studies comparing high-dose barbiturates to other sedatives (propofol, midazolam, ketamine, dexmedetomidine) in the context of burst suppression or severe TBI management were included. Data on sedative protocols (dosing and EEG targets), mechanisms of action, ICP-lowering efficacy, complications, and patient outcomes were extracted and analyzed qualitatively. Results: High-dose barbiturates (e.g., pentobarbital or thiopental) and propofol are both effective at inducing burst-suppression EEG and reducing ICP via cerebral metabolic suppression. Barbiturate coma remains a third-tier intervention reserved for ICP refractory to other treatments. Propofol infusion has become first-line for routine ICP control due to rapid titratability and shorter half-life, though it can also achieve burst suppression at high doses. Midazolam infusions provide sedation and seizure prophylaxis but yield less metabolic suppression and ICP reduction compared to barbiturates or propofol, and are associated with longer ventilation duration and delirium. Ketamine, once avoided for fear of raising ICP, has shown neutral or lowering effects on ICP when used in ventilated TBI patients, thanks to its analgesic properties and maintenance of blood pressure; however, ketamine alone does not reliably produce burst-suppression patterns. Dexmedetomidine offers sedative and anti-delirium benefits with minimal respiratory depression, but it is generally insufficient for deep burst-suppressive sedation and has only a modest effect on ICP. In comparative clinical evidence, propofol and barbiturates both effectively lower ICP, but neither has demonstrated clear improvement in long-term neurological outcome when used prophylactically. Early routine use of barbiturate coma may increase complications (hypotension, immunosuppression), and thus, current practice restricts it to refractory cases. Modern sedation protocols emphasize using the minimal necessary sedation to maintain ICP < 22 mmHg, with continuous EEG monitoring to titrate therapy to a burst-suppression target (commonly 2–5 bursts per minute) when deep coma is employed. Conclusions: In adult TBI patients with intracranial hypertension, propofol-based sedation is favored for first-line ICP control and can achieve burst suppression if needed, whereas high-dose barbiturates are reserved for ICP crises unresponsive to standard measures. Compared to barbiturates, alternative agents (propofol, midazolam, ketamine, dexmedetomidine) offer differing advantages: propofol provides potent, fast-acting metabolic suppression; midazolam adds anticonvulsant sedation for prolonged use at the cost of slower wake-up; ketamine supports hemodynamics and analgesia; dexmedetomidine aids lighter sedation and delirium control. The choice of agent is guided by the clinical scenario, balancing ICP reduction needs against side effect profiles. While all sedatives can transiently reduce ICP, careful monitoring and a tiered therapy approach are essential, as no sedative has conclusively improved long-term neurological outcomes in TBI. EEG monitoring for burst suppression and meticulous titration is required when employing barbiturate or propofol coma. Ongoing research into optimal combinations and protocols may further refine sedation strategies to improve safety and outcomes in severe TBI. Full article