Robotic-Assisted Transcranial Doppler Monitoring in Acute Neurovascular Care: a Feasibility and Safety Study

Robotic-Assisted Transcranial Doppler Monitoring in Acute Neurovascular Care: a Feasibility and Safety Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Robotic-Assisted Transcranial Doppler Monitoring in Acute Neurovascular Care: a Feasibility and Safety Study Alvise Fattorello Salimbeni, Caterina Kulyk, Francesco Favruzzo, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4545187/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 19 Sep, 2024 Read the published version in Neurocritical Care → Version 1 posted 5 You are reading this latest preprint version Abstract Introduction : Transcranial Color Doppler (TCD) is currently the only non-invasive bedside tool capable of providing real-time information on cerebral hemodynamics. However, being operator dependent, TCD monitoring is not feasible in many institutions. Robotic assisted TCD (ra-TCD) was recently developed to overcome these constraints. The aim of this study was to evaluate the safety and feasibility of cerebral monitoring with a novel ra-TCD in acute neurovascular care. Methods : This is a two-center prospective study conducted between August 2021 and February 2022 at Padua University Hospital (Padua, Italy) and Kepler University Hospital (Linz, Austria). Adult patients with conditions impacting on cerebral hemodynamics or undergoing invasive procedures affecting cerebral hemodynamics were recruited for prolonged monitoring (> 30 minutes) of the middle cerebral artery (MCA) with a novel ra-TCD (NovaGuide TM Intelligent Ultrasound, NeuraSignal, Los Angeles, CA, USA). Manual TCD was also performed for comparison by an experienced operator. Feasibility and safety rates were recorded. Results : 92 patients [age: mean 68.5 years, range 36-91; gender: male 57 (62%)] were enrolled in the two centers: 54 in Padua, 38 in Linz. The exam was feasible in the majority of patients (85.9%); the head cradle design and its radiopacity hindered its use during carotid endarterectomy and mechanical thrombectomy. Regarding safety, only one patient (1.1%) reported a minor local edema due to prolonged probe pressure. Velocity values resulted similar between ra-TCD and manual TCD. Discussion : This novel ra-TCD showed an excellent safety and feasibility, and proved to be as reliable as manual TCD in detecting blood flow velocities. These findings support its wider use for cerebral hemodynamics monitoring in acute neurovascular care. However, further technical improvements are needed to expand the range of applicable settings. Transcranial ultrasound neuromonitoring cerebral hemodynamics robotic artificial intelligence feasibility safety Figures Figure 1 Figure 2 Figure 3 INTRODUCTION Continuous monitoring of cerebral activity has become fundamental in neuro-critical care, 1 allowing to capture more aspects of the dynamic and multifaceted nature of the human brain compared to a single examination. Transcranial Color Doppler (TCD) is currently the only non-invasive bedside tool capable of providing real-time information on one of the crucial aspects of cerebral monitoring, namely cerebral hemodynamics. 2 – 4 Using a low frequency (2.0-2.5 MHz) ultrasound probe positioned on the thinner parts of the skull, known as “bone windows”, it allows the determination of different cerebral blood flow parameters. TCD was first introduced in neuro-critical care to monitor vasospasm in patients after subarachnoid hemorrhage. 5 Since then, the range of applications have widened remarkably. For example, TCD has the unique ability to detect microembolic signals (MES) in the cerebral circulation, namely transient high intensity signals that represent emboli passing through the intracranial vessels. 6 , 7 MES have been detected in many different clinical conditions and growing evidence supports TCD monitoring during several interventional and surgical procedures, as cardiac or vascular surgery 8 – 11 or even in the multimodal monitoring of patients undergoing liver transplant. 12 Up to now, implications of MES detection are still largely unexplored. 13 Furthermore, TCD could be a pivotal tool to monitor patients admitted to Intensive Care Units (ICU) with traumatic brain injury (TBI). In fact, several studies highlight the key role of TCD in the evaluation of cerebral autoregulation and for the early detection of intracranial hypertension. 4 , 14 – 16 Although the skull provided an ideal platform for mounting monitoring TCD probes, cerebral monitoring with TCD has been limited so far, because it still requires a trained sonographer for the entire duration of the examination, making it not feasible in many institutions. 17 Robotic assisted TCD (ra-TCD) was developed to overcome these constraints, using artificial intelligence to automatically detect intracranial blood flow signals and continue its monitoring without the constant need of an operator keeping the probe aimed right on its target. 18 The scope of our study was to evaluate the safety and feasibility of cerebral monitoring with ra-TCD in acute neurovascular care in comparison with manual TCD. METHODS Population This two-center prospective study took place between August 2021 and February 2022. Patients were enrolled at Padua University Hospital (Padua, Italy), henceforth referred to as P, and at Kepler University Hospital (Linz, Austria), henceforth referred to as L. Adult patients affected by conditions impacting on cerebral hemodynamics or undergoing invasive procedures that might influence cerebral hemodynamics were enrolled from the Stroke Unit (P and L), the Neurointensive Care Unit (P and L), the general intensive care unit (P and L), the cardiological (L) and neurological (P) neurovascular intervention suite and the operating theater for patients undergoing carotid endarterectomy (L). All patients received TCD evaluation in the context of routinary clinical care. Patients with open skull fractures or recent decompressive craniectomy were excluded to avoid mechanical damage on soft tissues. The study was approved by the Research Ethics Committees of both centers and informed consent was obtained from all individual participants included. Monitoring protocol The patients underwent ra-TCD (NovaGuide™ Intelligent Ultrasound, NeuraSignal, Los Angeles, CA, USA) monitoring of both middle cerebral arteries (MCA) for at least 30 minutes (Figs. 1 , 2 , 3 ). This system, which blends artificial intelligence, robotics and ultrasound, is composed of two distinct parts: the Lucid™ Transcranial Doppler, a TCD device with two 2 MHz probes already in use for clinical practice, and the NovaBot™, a novel device which was specifically developed to automatically guide the TCD probes for the acquisition of cerebral blood flow. The probes are attached to a head-cradle to provide further stabilization. They are robotically assisted to detect the MCA signal through the transtemporal window and reposition automatically in case of slight head movements. All examinations were performed with patients lying supine. Specifically, the patient’s head was positioned into a specific head cradle and a forehead piece was attached in order to guarantee further stabilization. Then, registration dots were applied on the tragus of the ear and lateral canthus of the eye bilaterally to indicate the potential transtemporal window. The probes were manually attached to the patient’s temporal bone. Cameras on the device captured images of the registration dots on the patient’s head and machine vision technology aligned the patient with the robotic system using those markers. Once aligned, the software identified an area for the examination and the device autonomously searched for the best spot to assess blood flow through the temporal bone. The medical professional confirmed this area, and the device automatically located a suitable spot to measure blood flow in the MCA, optimizing the signal for accurate readings. During this process, the system quickly evaluated signal quality in real-time, ensuring that the measurements accurately reflected the current blood flow dynamics of the MCA. To maximize safety, mechanical and thermal indexes were kept as low as possible according to the ALARA (As Low As Reasonably Achievable) principle. Failure of the device to localize the MCA signal was defined after 15 minutes of automated search; in this case, an experienced operator (CK, AFS, FF, AP, MV) located the MCA signal manually. All patients also underwent manual TCD in order to compare Peak Systolic Velocitiy (PSV) and End Diastolic Velocity (EDV) values with those obtained with ra-TCD. Outcomes Feasibility was defined as the percentage of patients in whom the examination could be performed on both sides (with or without manual adjustment). Operational times required for the set-up of the device and search of the MCA signal were recorded. Complications were divided into major (requiring immediate medical assistance and discontinuation of the exam), and minor events (not requiring immediate medical assistance). Blood flow velocities in the MCA were compared between ra-TCD and manual TCD to search for potential significant differences. Statistical analyses Demographic and clinical data were analyzed with Jamovi computer software (v.2.5, The Jamovi project, Sidney, Australia, https://www.jamovi.org ). Continuous variables were presented as median and interquartile range (IQ) or minimum-maximum range (min-max), while categorical data as number and percentage. Comparison of blood flow velocities was performed with Student’s t-test. A p-value inferior to 0.05 was considered significant. RESULTS Demographic and clinical data Between August 1st, 2021 and August 1st, 2022, 92 patients were enrolled in the two centers (54 in Padua, 38 in Linz). Patients were mainly recruited in the Neurology wards (Stroke Unit and general neurology ward, 60.9%), followed by the ICU (neurological and general, 32.6%), the angio-suite (5.4%) and the operating theater (1.1%) (Table 1 ). Ischemic stroke was the cause of admission in 54 (58.7%) patients, followed by spontaneous SAH (14.2%). Five patients (5.4%) were being treated with extracorporeal membrane oxygenation (ECMO) at the time of evaluation, while 14 (15.2%) presented a continuous intracerebral pressure (ICP) monitoring device. Forty-two patients (45.6%) were under deep sedation or general anesthesia (Glasgow Coma Scale = 3) when ra-TCD monitoring was performed. Table 1 Demographic and clinical characteristics Number of patients = 92 Demographic data Median age, (IQR) 68.5 years (36–91) Male, n (%) 57 (62) Clinical Data Main diagnosis - Ischemic stroke, n (%) - Spontaneous SAH, n (%) - Traumatic SAH, n (%) - Anoxic brain injury, n (%) - COVID-19 related respiratory failure, n (%) - Aortic valve stenosis, n (%) - Traumatic ICH, n (%) - Other (PRES, carotid body paraganglioma, aortic dissection, asymptomatic carotid stenosis), n (%) 54 (58.7) 13 (14.2) 8 (8.7) 4 (4.3) 4 (4.3) 3 (3.3) 2 (2.2) 4 (4.3) Sedation or general anesthesia, n (%) 42 (45.6) ECMO, n (%) - Veno-venous, n (%) - Veno-arteriovenous, n (%) 5 (5.5) - 3 (3.2) - 2 (2.2) ICP monitoring system, n (%) 14 (15.2) Clinical setting - Neurology wards (Stroke Unit & general) - ICU (neurological & cardiological) - Angio Suite (cardiological & neurological) - Operating Room - 56 (60.9) - 30 (32.6) - 5 (5.4) - 1 (1.1) Abbreviations. IQR: interquartile range; n: number; SAH: subarachnoid hemorrhage; ICH: intracerebral hemorrhage; PRES: posterior reversible encephalopathy syndrome; ECMO: extracorporeal membrane oxygenation; ICP: intracerebral pressure; ICU: intensive care unit Feasibility and safety The exam was feasible in the majority of our patients (85.9%), as reported in Table 2 . In nine patients (9.7%) the ra-TCD was not feasible because of individual head or neck anatomy (eg. short neck) that impeded correct positioning of the device. Moreover, in 2 out of 14 patients with an ICP monitoring system the exam could not be performed because the intracranial probe hindered the position of the head cradle. Ra-TCD was feasible in all five patients with ECMO. Continuous cerebral monitoring with ra-TCD was possible in all patients undergoing cardiological interventional procedures (four patients), however it could not be performed during mechanical thrombectomy, since the ultrasound probes are radio-opaque, thus interfering with the necessary radioscopic imaging performed during the procedure. Lastly, ra-TCD was not feasible in the patient undergoing surgical carotid endarterectomy, since the head cradle interfered with the access to the surgical site. Table 2 Exam feasibility and safety Number of patients = 92 Feasibility Ra-TCD overall feasibility, n (%) - Neurology wards (Stroke Unit, general) - ICU (neurological & cardiological) - Angio Suite (cardiological & neurological) - Operating Room 79 (85.9) - 49/56 (87.5) - 26/30 (86.7) - 4/5 (80) - 0/1 (0) Causes of non-feasibility, n (%) - Head or neck anatomy, n (%) - ICP monitoring device localization, n (%) - Obstruction to surgical procedures, n (%) - Non-radiopacity (for EVT), n (%) 13 (14.1) - 9 (9.7) - 2 (2.2) - 1 (1.1) - 1 (1.1) Feasibility with ECMO (n = 5), n (%) 5/5 (100) Feasibility with ICP monitoring device (n = 14), n (%) 12/14 (86) Safety Major complications, n (%) 0 Minor complications, n (%) 1 (1.1) Abbreviations. Ra-TCD: Robotic assisted-TCD; n: Number; ICU: Intensive Care Unit; ICP: intracerebral pressure; EVT: endovascular treatment; ECMO: extracorporeal membrane oxygenation. A minor complication was reported only in one patient (1.1%), namely a localized, self-limiting and quickly resolving subcutaneous edema due to mechanical pressure of the TCD probe positioned on the temporal bone window. This complication did not constitute a matter of concern. Detection rates and time intervals Among those 79 patients in whom the examination was feasible, ra-TCD automatically identified an optimal MCA signal in 124 out of 158 (78.5%) temporal bone windows, with a median detection time of 2 minutes and 18 seconds. Hence, in this study, ra-TCD showed a good overall rate of autonomous MCA detection (78.5%), in agreement with studies conducted among adults of all ages. 19 – 21 When MCA signal was not automatically detected within 15 minutes of search, manual search mode led to the identification of 9 additional MCA Doppler signals, increasing the overall detection rate to 84.2%. The median time of ra-TCD monitoring was 34 minutes. Seven (8.9%) exams were interrupted earlier due to the patient's discomfort (6.3%) or acute clinical events (cardiac arrest, severe agitation) (2.6%) requiring urgent medical intervention (Table 3 ). Table 3 Exam specifics Number of patients = 79 Time of set-up, median (min-max) 13.5 mins (5.1–21.3) Time needed to detect MCA, median (min-max) 2.3 mins (0.1–14.5) Automatic signal detection rate, n (%) 124/158 (78.5%) MCA signal detection rate with manual intervention, n (%) 133/158 (84.2%) Duration of TCD monitoring, median (min-max) 34 mins (9-150) Early interruption of the exam due to: - Patient’s discomfort - Medical emergencies 7/79 (8.9%) - 5/79 (6.3%) - 2/79 (2.6%) PSV difference (Ra-TCD vs manual TCD), median (min-max) + 8.8 cm/s (-6.8 - +18.1) p = 0.891 EDV difference (Ra-TCD vs manual TCD), median (min-max) + 6.8 cm/s (-4.1 - +7.1) p = 0.671 Abbreviations. Min: minimum; Max: maximum; MCA: Middle Cerebral Artery; N: number; PSV: Peak Systolic Velocity; EDV: End Diastolic Velocity. Velocity comparison between ra-TCD and manual TCD Among those 79 patients in whom ra-TCD was feasibile, we compared PSV and EDV values of the MCA obtained with ra-and manual TCD. The median difference between ra-TCD and manual TCD was + 8.8 cm/s (min-max: -6.8 - +18.1) for PSV and + 6.8 cm/s (min-max: -4.1 - +7.1) for EDV, i.e. not statistically significant (p = 0.891 for PSV and 0.671 for EDV). DISCUSSION Robotically assisted devices in medicine represent a promising field that has been only partially applied to clinical practice. Initial evidence regarding the application of ra-TCD for a single-shot examination has been reported for instance by a multicenter study comparing ra-TCD and transthoracic echocardiogram for right-to-left shunt detection in stroke patients suggesting ra-TCD to be more effective. 22 However, our study is the first to show that this new ra-TCD system allows to easily monitor cerebral hemodynamics in different hospital settings. Feasibility in our population was remarkably high overall. Intensive care patients could be monitored for a few hours despite the presence of different invasive equipment such as endotracheal tube, tracheostomy and ECMO. In patients with an ICP probe the examination could be completed in most cases, except for two with a posterior site of insertion of the intracranial probe. Our study is the largest to date testing ra-TCD in the intensive care setting, confirming preliminary data of a study on 12 patients with subarachnoid hemorrhage that showed safety and efficacy of the same device. 23 Due to its numerous applications, TCD has also been described as the “stethoscope of the brain” for critically ill patients. 15 In fact, it easily allows an early identification of cerebral hemodynamic alterations, such as vasospasm, altered cerebral autoregulation, pulsatility index rise thus guiding clinical management. Ra-TCD, being operator-independent, might further boost this technique allowing prolonged monitoring of cerebral hemodynamics, thus becoming an integral part of neuromonitoring. The highest feasibility was demonstrated in the stroke unit and the general neurological ward, with only a minority of cases where the examination was impeded by uncommon anatomical characteristics of patients. This preliminary data opens the field to the potential application of continuous monitoring of cerebral hemodynamics in ischemic stroke patients, for example after thrombectomy, where flow parameters in the recanalized vessel have shown to correlate with prognosis. 24 – 26 Another possible application of ra-TCD is the prolonged monitoring of MCA signal in patients with asymptomatic carotid artery stenosis, where the detection of MES in the ipsilateral MCA significantly increases the risk to develop ischemic stroke. 27 Prolonged monitoring would raise the chances of MES detection and help identify atherosclerotic plaques at higher risk of distal embolization. 27 Concerning the comparison of blood flow velocities among ra-TCD and manual TCD, our study did not find any statistical difference. No real-world studies are available in literature comparing ra-TCD and manual TCD. However, since the device we utilized employs an already validated and widely tested TCD we think these results reinforce the validity of ra-ultrasound devices and their potential to expand hemodynamics monitoring in neurovascular patients. Regarding TCD-related complications, only one patient reported moderate transient unilateral subcutaneous edema in the temporal region due to the probe’s mechanical pressure. The edema regressed quickly and spontaneously right after the end of the examination, and it was not considered a matter of concern by the authors. Nonetheless, it would be advisable to reduce the probe pressure on the temple. No similar reports are available in the literature, although the experience is scant so far. A previous study performing non-monitoring TCD examinations in 129 patients proved the device to be safe. Specifically, no serious adverse events were reported, while only two non-serious events were documented both unrelated to the device. 23 TCD is a unique tool in detecting microemboli entering the MCA during heart surgery and cardiologic procedures, although the clinical relevance of these findings is still debated. 8 , 9 In our study, prolonged TCD monitoring was easily performed during cardiological interventional procedures, opening the field for exploration of cerebral hemodynamic parameters and MES detection in this very interesting setting. On the other hand, ra-TCD was not feasible during neurological interventional procedures such as acute mechanical thrombectomy and carotid stenting, because the probes were radiopaque, not allowing patients to undergo intraprocedural radiological checks. An updated version of the ra-TCD with radiotransparent probes has been recently released, but it needs to be re-evaluated in this setting. Ra-TCD was also not feasible during open carotid surgery, because the size of the device interfered with the surgical field. This is a drawback, as detection of MES during CEA showed a significant relationship with perioperative cerebral complications and new ischemic lesions in different studies. 10 , 11 Ra-TCD has a great potential as it could be applied to study the risk of perioperative cerebral complications after different kinds of surgery (eg. orthopedic surgery), expanding the data of first explorative reports. 29 Altogether, the results of the current study show the need for further technological advancement to perform operator-independent monitoring of cerebral hemodynamics and guide the improvement of cardiovascular or neurovascular procedures to reduce stroke burden. CONCLUSIONS To conclude, this novel ra-TCD was found to be a safe and feasible bedside tool for real-time monitoring of cerebral hemodynamics. Blood flow velocities do not differ significantly between ra-TCD and manual TCD. Further technical improvements are needed to expand the range of its applicability, allowing to systematically perform prolonged hemodynamics monitoring in neurovascular patients. Declarations The authors confirm that this manuscript complies with all “instructions to authors”. The authors confirm that authorship requirements have been met and the final manuscript was approved by all authors. The authors confirm that this manuscript has not been published elsewhere and is not under consideration by another journal. The study was approved by the Research Ethics Committees of both centers and informed consent was obtained from all individual participants included. FUNDING: this study was not supported by any funding. DISCLOSURES: The authors have no disclosures for this study. ACKNOWLEDGMENTS : none. AUTHORS CONTRIBUTIONS: Fattorello Salimbeni Alvise: Conceptualization, Methodology, Neurosonological evaluation, Formal analysis, Data Curation, Writing - Original Draft. Kulyk Caterina: Conceptualization, Methodology, Neurosonological evaluation, Formal analysis, Data Curation, Writing - Original Draft. Favruzzo Francesco: Neurosonological evaluation, Writing - Original Draft. De Rosa Ludovica: Neurosonological evaluation, Formal analysis, Data Curation. Viaro Federica: Neurosonological evaluation, Formal analysis, Data Curation. Pieroni Alessio: Neurosonological evaluation, Formal analysis, Data Curation. Mozzetta Stefano: Neurosonological evaluation, Formal analysis, Data Curation. Vosko R Milan: Writing - Review & Editing, Supervision, Project administration. Baracchini Claudio: Writing - Review & Editing, Supervision, Project administration. References Roh D, Park S. Brain multimodality monitoring: updated perspectives. Curr Neurol Neurosci Rep 2016;16:56. https://doi.org/10.1007/s11910-016-0659-0. Aaslid R, Markwalder TM, Nornes H. Noninvasive transcranial Doppler ultrasound recording of flow velocity in basal cerebral arteries. J Neurosurg 1982; 57:769-774. https://doi.org/10.3171/jns.1982.57.6.0769. Robba C, Goffi A, Geeraerts T, et al. Brain ultrasonography: methodology, basic and advanced principles and clinical applications. A narrative review. Intensive Care Med 2019;45:913-927. https://doi.org/10.1007/s00134-019-05610-4. Rodriguez CN, Baracchini C, Mantilla JHM et al. Neurosonology in critical care: monitoring the neurological impact of the critical pathology. Cham, Switzerland: Springer Nature Switzerland; 2022:1149. Lindegaard KF, Nornes H, Bakke SJ, Sorteberg W, Nakstad P. Cerebral vasospasm diagnosis by means of angiography and blood velocity measurements. Acta Neurochir 1989;100:12-24. https://doi.org/10.1007/BF01405268. Russell D. The detection of cerebral emboli using doppler ultrasound. In: Newell DW and Aaslid R, ed. Transcranial Doppler. New York, NY: Raven Press Publishers; 2017:207-213. https://doi.org/10.1515/bmte.1999.44.4.87. Ringelstein EB, Droste DW, Babikian VI et al. Consensus on microembolus detection by TCD. Stroke 1998;29:725-729. https://doi.org/10.1161/01.str.29.3.725. King A, Markus HS. Doppler embolic signals in cerebrovascular disease and prediction of stroke risk: a systematic review and meta-analysis. Stroke 2009;40:3711-7. https://doi.org/10.1161/STROKEAHA.109.563056. Stygall J, Kong R, Walker JM et al. Cerebral microembolism detected by transcranial Doppler during cardiac procedures. Stroke 2000;31:2508-10. https://doi.org/10.1161/01.str.31.10.2508. Dittrich R, Ringelstein EB. Occurrence and clinical impact of microembolic signals during or after cardiosurgical procedures. Stroke 2008;39:503-11. https://doi.org/10.1161/STROKEAHA.107.491241. Ackerstaff RG, Jansen C, Moll FL et al. The significance of microemboli detection by means of transcranial Doppler ultrasonography monitoring in carotid endarterectomy. J Vasc Surg 1995;21:963-9. https://doi.org/10.1016/s0741-5214(95)70224-5. Cardim D, Robba C, Schmidt E et al. Transcranial Doppler Non-invasive Assessment of Intracranial Pressure, Autoregulation of Cerebral Blood Flow and Critical Closing Pressure during Orthotopic Liver Transplant. Ultrasound in medicine & biology 2019;45(6):1435-1445. https://doi.org/10.1016/j.ultrasmedbio.2019.02.003. Udesh R, Natarajan P, Thiagarajan K et al. Transcranial doppler monitoring in carotid endarterectomy: a systematic review and meta-analysis. J Ultrasound Med 2017;36:621-630. https://doi.org/10.7863/ultra.16.02077. Gelormini C, Ioannoni E, Scavone A et al. Hyperemia in head injury: can transcranial doppler help to personalize therapies for intracranial hypertension? Front Neurol 2023;14:1259180. https://doi.org/10.3389/fneur.2023.1259180. Robba C, Taccone FS. How I use Transcranial Doppler. Crit Care 2019;23:420. doi:10.1186/s13054-019-2700-6. Martínez-Palacios K, Vásquez-García S, Fariyike OA et al. Non-Invasive Methods for Intracranial Pressure Monitoring in Traumatic Brain Injury Using Transcranial Doppler: A Scoping Review. Journal of neurotrauma 2024;10.1089/neu.2023.0001. https://doi.org/10.1089/neu.2023.0001. Baracchini C, Azevedo E, Walter U et al. Neurosonology survey in Europe and beyond. Ultrasound International Open 2024; 10:a22439625. https://doi.org/10.1055/a-2243-9625. O’Brien MJ, Dorn AY, Ranjbaran M et al. Fully automated transcranial doppler ultrasound for middle cerebral artery insonation. J Neurosonol Neuroimag 2022;14:27-34. https://doi.org/10.31728/jnn.2021.00110. Itoh T, Matsumoto M, Handa N et al. Rate of successful recording of blood flow signals in the middle cerebral artery using transcranial Doppler sonography. Stroke 1993;24:1192-5. https://doi.org/10.1161/01.str.24.8.1192. Wijnhoud AD, Franckena M, van der Lugt A et al. Inadequate acoustical temporal bone window in patients with a transient ischemic attack or minor stroke: role of skull thickness and bone density. Ultrasound Med Biol 2008;34:923-9. https://doi.org/10.1016/j.ultrasmedbio.2007.11.022. He L, Wu DF, Zhang JH et al. Factors affecting transtemporal window quality in transcranial sonography. Brain Behav 2022;12:e2543. doi:10.1002/brb3.2543. Rubin MN, Shah R, Devlin T et al. Robot-assisted transcranial doppler versus transthoracic echocardiography for right to left shunt detection. Stroke 2023;54:2842-2850. https://doi.org/10.1161/STROKEAHA.123.043380. Clare K, Stein A, Damodara N et al. Safety and efficacy of a novel robotic transcranial doppler system in subarachnoid hemorrhage. Sci Rep 2022;12: 2266. https://doi.org/10.1038/s41598-021-04751-1. Baracchini C, Farina F, Palmieri A et al. Early hemodynamic predictors of good outcome and reperfusion injury after endovascular treatment. Neurology 2019;11:92. https://doi.org/10.1212/WNL.0000000000007646. Castro P, Ferreira J, Malojcic B et al. Detection of microemboli in patients with acute ischaemic stroke and atrial fibrillation suggests poor functional outcome. Eur Stroke J 2023;23969873231220508. https://doi.org/10.1177/23969873231220508. Farina F, Palmieri A, Favaretto S et al. Prognostic role of microembolic signals after endovascular treatment in anterior circulation ischemic stroke patients. World Neurosurg.2018;110:e882-e889. https://doi.org/10.1016/j.wneu.2017.11.120. Markus HS, King A, Shipley M et al. Asymptomatic embolisation for prediction of stroke in the Asymptomatic Carotid Emboli Study (ACES): a prospective observational study. Lancet Neurol 2010;9:663-71. https://doi.org/10.1016/S1474-4422(10)70120-4. Spence JD, Tamayo A, Lownie SP et al. Absence of microemboli on transcranial Doppler identifies low-risk patients with asymptomatic carotid stenosis. Stroke 2005;36:2373-8. https://doi.org/10.1161/01.STR.0000185922.49809.46. Silbert BS, Evered LA, Scott DA et al. Review of transcranial Doppler ultrasound to detect microemboli during orthopedic surgery. Am J Neuroradiol 2014;35:1858-63. https://doi.org/10.3174/ajnr.A3688. Cite Share Download PDF Status: Published Journal Publication published 19 Sep, 2024 Read the published version in Neurocritical Care → Version 1 posted Reviewers agreed at journal 19 Jun, 2024 Reviewers invited by journal 19 Jun, 2024 Editor invited by journal 12 Jun, 2024 Editor assigned by journal 11 Jun, 2024 First submitted to journal 10 Jun, 2024 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4545187","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":316516509,"identity":"e98c973e-93c4-4127-8913-ad9de74a65c1","order_by":0,"name":"Alvise Fattorello Salimbeni","email":"data:image/png;base64,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","orcid":"https://orcid.org/0009-0002-0521-5118","institution":"Padua University Hospital: Azienda Ospedale Universita Padova","correspondingAuthor":true,"prefix":"","firstName":"Alvise","middleName":"Fattorello","lastName":"Salimbeni","suffix":""},{"id":316516510,"identity":"a20db9f9-cf0d-4554-9d6a-450b8812f8d1","order_by":1,"name":"Caterina Kulyk","email":"","orcid":"","institution":"Kepler Universitätsklinikum GmbH: Kepler Universitatsklinikum GmbH","correspondingAuthor":false,"prefix":"","firstName":"Caterina","middleName":"","lastName":"Kulyk","suffix":""},{"id":316516511,"identity":"adcf0885-18c9-4022-8cb7-d6910e54dee6","order_by":2,"name":"Francesco Favruzzo","email":"","orcid":"","institution":"Padua University Hospital: Azienda Ospedale Universita Padova","correspondingAuthor":false,"prefix":"","firstName":"Francesco","middleName":"","lastName":"Favruzzo","suffix":""},{"id":316516512,"identity":"adbb1fb2-f618-49f2-b675-5e9f3d0091c6","order_by":3,"name":"Ludovica De Rosa","email":"","orcid":"","institution":"Padua University Hospital: Azienda Ospedale Universita Padova","correspondingAuthor":false,"prefix":"","firstName":"Ludovica","middleName":"","lastName":"De Rosa","suffix":""},{"id":316516513,"identity":"839281d4-50c6-4d30-95f8-d9bae42ea47b","order_by":4,"name":"Federica Viaro","email":"","orcid":"","institution":"Padua University Hospital: Azienda Ospedale Universita Padova","correspondingAuthor":false,"prefix":"","firstName":"Federica","middleName":"","lastName":"Viaro","suffix":""},{"id":316516514,"identity":"0a5f71ce-3e97-4eb7-a92b-fab960e2a14c","order_by":5,"name":"Alessio Pieroni","email":"","orcid":"","institution":"Padua University Hospital: Azienda Ospedale Universita Padova","correspondingAuthor":false,"prefix":"","firstName":"Alessio","middleName":"","lastName":"Pieroni","suffix":""},{"id":316516515,"identity":"7e03be6b-77df-4bad-b773-4827cf1c6f13","order_by":6,"name":"Stefano Mozzetta","email":"","orcid":"","institution":"Padua University Hospital: Azienda Ospedale Universita Padova","correspondingAuthor":false,"prefix":"","firstName":"Stefano","middleName":"","lastName":"Mozzetta","suffix":""},{"id":316516516,"identity":"a2f92b70-6b9e-4e4a-a325-f567107a36f6","order_by":7,"name":"Milan R Vosko","email":"","orcid":"","institution":"Kepler Universitätsklinikum GmbH: Kepler Universitatsklinikum GmbH","correspondingAuthor":false,"prefix":"","firstName":"Milan","middleName":"R","lastName":"Vosko","suffix":""},{"id":316516517,"identity":"d950f64a-82df-49a4-a011-e153cfa1fd43","order_by":8,"name":"Claudio Baracchini","email":"","orcid":"","institution":"Padua University Hospital: Azienda Ospedale Universita Padova","correspondingAuthor":false,"prefix":"","firstName":"Claudio","middleName":"","lastName":"Baracchini","suffix":""}],"badges":[],"createdAt":"2024-06-07 09:34:25","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4545187/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4545187/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s12028-024-02121-z","type":"published","date":"2024-09-19T15:58:05+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":60448490,"identity":"4d261de1-86d7-4f44-bad4-d6e8b0134e84","added_by":"auto","created_at":"2024-07-16 22:15:43","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":5525327,"visible":true,"origin":"","legend":"\u003cp\u003eRobotic assisted TCD (Novaguide\u003csup\u003eTM\u003c/sup\u003e Intelligent Ultrasound, NeuraSignal Incorporated) in Angio Suite.\u003csup\u003e \u003c/sup\u003e(Original image)\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4545187/v1/81d4353e94e0f952d9aa0a38.jpg"},{"id":60448492,"identity":"2a66fe06-7589-4bc4-b8db-0d9f022f26e6","added_by":"auto","created_at":"2024-07-16 22:15:44","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":6008343,"visible":true,"origin":"","legend":"\u003cp\u003eRobotic assisted TCD (Novaguide\u003csup\u003eTM\u003c/sup\u003e Intelligent Ultrasound, NeuraSignal Incorporated) in ICU.\u003csup\u003e \u003c/sup\u003e(Original image)\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4545187/v1/ec20412c7049ee935f197799.jpg"},{"id":60448489,"identity":"2bb486df-6ec2-48a8-830c-d6572ac3ca65","added_by":"auto","created_at":"2024-07-16 22:15:43","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":194047,"visible":true,"origin":"","legend":"\u003cp\u003eRobotic assisted TCD, Novaguide TM Intelligent Ultrasound, NeuraSignal Incorporated. (Image originally published in Clare K, Stein A, Damodara N et al. Safety and efficacy of a novel robotic transcranial doppler system in subarachnoid hemorrhage. Sci Rep 2022;12: 2266. Permission for reproduction was provided by the author, Dr. R. Hamilton)\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-4545187/v1/f42a4523b30f31328e98fe9d.jpg"},{"id":65431713,"identity":"59be71ba-b6c0-4fd9-95f5-a6e1d8e0c75d","added_by":"auto","created_at":"2024-09-27 11:59:05","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":12152355,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4545187/v1/cb834d92-de87-409c-acd8-cb7a3c12cc74.pdf"}],"financialInterests":"","formattedTitle":"\u003cp\u003eRobotic-Assisted Transcranial Doppler Monitoring in Acute Neurovascular Care: a Feasibility and Safety Study\u003c/p\u003e","fulltext":[{"header":"INTRODUCTION","content":"\u003cp\u003eContinuous monitoring of cerebral activity has become fundamental in neuro-critical care,\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e allowing to capture more aspects of the dynamic and multifaceted nature of the human brain compared to a single examination. Transcranial Color Doppler (TCD) is currently the only non-invasive bedside tool capable of providing real-time information on one of the crucial aspects of cerebral monitoring, namely cerebral hemodynamics.\u003csup\u003e\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u003c/sup\u003e Using a low frequency (2.0-2.5 MHz) ultrasound probe positioned on the thinner parts of the skull, known as \u0026ldquo;bone windows\u0026rdquo;, it allows the determination of different cerebral blood flow parameters. TCD was first introduced in neuro-critical care to monitor vasospasm in patients after subarachnoid hemorrhage.\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e Since then, the range of applications have widened remarkably. For example, TCD has the unique ability to detect microembolic signals (MES) in the cerebral circulation, namely transient high intensity signals that represent emboli passing through the intracranial vessels.\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e,\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u003c/sup\u003e MES have been detected in many different clinical conditions and growing evidence supports TCD monitoring during several interventional and surgical procedures, as cardiac or vascular surgery\u003csup\u003e\u003cspan additionalcitationids=\"CR9 CR10\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e or even in the multimodal monitoring of patients undergoing liver transplant.\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e Up to now, implications of MES detection are still largely unexplored.\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e Furthermore, TCD could be a pivotal tool to monitor patients admitted to Intensive Care Units (ICU) with traumatic brain injury (TBI). In fact, several studies highlight the key role of TCD in the evaluation of cerebral autoregulation and for the early detection of intracranial hypertension.\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e,\u003cspan additionalcitationids=\"CR15\" citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e Although the skull provided an ideal platform for mounting monitoring TCD probes, cerebral monitoring with TCD has been limited so far, because it still requires a trained sonographer for the entire duration of the examination, making it not feasible in many institutions.\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e Robotic assisted TCD (ra-TCD) was developed to overcome these constraints, using artificial intelligence to automatically detect intracranial blood flow signals and continue its monitoring without the constant need of an operator keeping the probe aimed right on its target.\u003csup\u003e\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e The scope of our study was to evaluate the safety and feasibility of cerebral monitoring with ra-TCD in acute neurovascular care in comparison with manual TCD.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePopulation\u003c/h2\u003e \u003cp\u003eThis two-center prospective study took place between August 2021 and February 2022. Patients were enrolled at Padua University Hospital (Padua, Italy), henceforth referred to as P, and at Kepler University Hospital (Linz, Austria), henceforth referred to as L. Adult patients affected by conditions impacting on cerebral hemodynamics or undergoing invasive procedures that might influence cerebral hemodynamics were enrolled from the Stroke Unit (P and L), the Neurointensive Care Unit (P and L), the general intensive care unit (P and L), the cardiological (L) and neurological (P) neurovascular intervention suite and the operating theater for patients undergoing carotid endarterectomy (L). All patients received TCD evaluation in the context of routinary clinical care. Patients with open skull fractures or recent decompressive craniectomy were excluded to avoid mechanical damage on soft tissues. The study was approved by the Research Ethics Committees of both centers and informed consent was obtained from all individual participants included.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eMonitoring protocol\u003c/h2\u003e \u003cp\u003eThe patients underwent ra-TCD (NovaGuide\u0026trade; Intelligent Ultrasound, NeuraSignal, Los Angeles, CA, USA) monitoring of both middle cerebral arteries (MCA) for at least 30 minutes (Figs.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, \u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). This system, which blends artificial intelligence, robotics and ultrasound, is composed of two distinct parts: the Lucid\u0026trade; Transcranial Doppler, a TCD device with two 2 MHz probes already in use for clinical practice, and the NovaBot\u0026trade;, a novel device which was specifically developed to automatically guide the TCD probes for the acquisition of cerebral blood flow. The probes are attached to a head-cradle to provide further stabilization. They are robotically assisted to detect the MCA signal through the transtemporal window and reposition automatically in case of slight head movements. All examinations were performed with patients lying supine. Specifically, the patient\u0026rsquo;s head was positioned into a specific head cradle and a forehead piece was attached in order to guarantee further stabilization. Then, registration dots were applied on the tragus of the ear and lateral canthus of the eye bilaterally to indicate the potential transtemporal window. The probes were manually attached to the patient\u0026rsquo;s temporal bone. Cameras on the device captured images of the registration dots on the patient\u0026rsquo;s head and machine vision technology aligned the patient with the robotic system using those markers. Once aligned, the software identified an area for the examination and the device autonomously searched for the best spot to assess blood flow through the temporal bone. The medical professional confirmed this area, and the device automatically located a suitable spot to measure blood flow in the MCA, optimizing the signal for accurate readings. During this process, the system quickly evaluated signal quality in real-time, ensuring that the measurements accurately reflected the current blood flow dynamics of the MCA. To maximize safety, mechanical and thermal indexes were kept as low as possible according to the ALARA (As Low As Reasonably Achievable) principle. Failure of the device to localize the MCA signal was defined after 15 minutes of automated search; in this case, an experienced operator (CK, AFS, FF, AP, MV) located the MCA signal manually. All patients also underwent manual TCD in order to compare Peak Systolic Velocitiy (PSV) and End Diastolic Velocity (EDV) values with those obtained with ra-TCD.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eOutcomes\u003c/h2\u003e \u003cp\u003eFeasibility was defined as the percentage of patients in whom the examination could be performed on both sides (with or without manual adjustment). Operational times required for the set-up of the device and search of the MCA signal were recorded.\u003c/p\u003e \u003cp\u003eComplications were divided into major (requiring immediate medical assistance and discontinuation of the exam), and minor events (not requiring immediate medical assistance).\u003c/p\u003e \u003cp\u003eBlood flow velocities in the MCA were compared between ra-TCD and manual TCD to search for potential significant differences.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analyses\u003c/h2\u003e \u003cp\u003eDemographic and clinical data were analyzed with Jamovi computer software (v.2.5, The Jamovi project, Sidney, Australia, \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://www.jamovi.org\u003c/span\u003e\u003cspan address=\"https://www.jamovi.org\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e). Continuous variables were presented as median and interquartile range (IQ) or minimum-maximum range (min-max), while categorical data as number and percentage. Comparison of blood flow velocities was performed with Student\u0026rsquo;s t-test. A p-value inferior to 0.05 was considered significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eDemographic and clinical data\u003c/h2\u003e \u003cp\u003eBetween August 1st, 2021 and August 1st, 2022, 92 patients were enrolled in the two centers (54 in Padua, 38 in Linz). Patients were mainly recruited in the Neurology wards (Stroke Unit and general neurology ward, 60.9%), followed by the ICU (neurological and general, 32.6%), the angio-suite (5.4%) and the operating theater (1.1%) (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Ischemic stroke was the cause of admission in 54 (58.7%) patients, followed by spontaneous SAH (14.2%). Five patients (5.4%) were being treated with extracorporeal membrane oxygenation (ECMO) at the time of evaluation, while 14 (15.2%) presented a continuous intracerebral pressure (ICP) monitoring device. Forty-two patients (45.6%) were under deep sedation or general anesthesia (Glasgow Coma Scale\u0026thinsp;=\u0026thinsp;3) when ra-TCD monitoring was performed.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDemographic and clinical characteristics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNumber of patients\u0026thinsp;=\u0026thinsp;92\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eDemographic data\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMedian age, (IQR)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e68.5 years (36\u0026ndash;91)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMale, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e57 (62)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eClinical Data\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eMain diagnosis\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e- Ischemic stroke, n (%)\u003c/p\u003e \u003cp\u003e- Spontaneous SAH, n (%)\u003c/p\u003e \u003cp\u003e- Traumatic SAH, n (%)\u003c/p\u003e \u003cp\u003e- Anoxic brain injury, n (%)\u003c/p\u003e \u003cp\u003e- COVID-19 related respiratory failure, n (%)\u003c/p\u003e \u003cp\u003e- Aortic valve stenosis, n (%)\u003c/p\u003e \u003cp\u003e- Traumatic ICH, n (%)\u003c/p\u003e \u003cp\u003e- Other (PRES, carotid body paraganglioma, aortic dissection, asymptomatic carotid stenosis), n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e54 (58.7)\u003c/p\u003e \u003cp\u003e13 (14.2)\u003c/p\u003e \u003cp\u003e8 (8.7)\u003c/p\u003e \u003cp\u003e4 (4.3)\u003c/p\u003e \u003cp\u003e4 (4.3)\u003c/p\u003e \u003cp\u003e3 (3.3)\u003c/p\u003e \u003cp\u003e2 (2.2)\u003c/p\u003e \u003cp\u003e4 (4.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSedation or general anesthesia, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e42 (45.6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eECMO, n (%)\u003c/p\u003e \u003cp\u003e- Veno-venous, n (%)\u003c/p\u003e \u003cp\u003e- Veno-arteriovenous, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (5.5)\u003c/p\u003e \u003cp\u003e- 3 (3.2)\u003c/p\u003e \u003cp\u003e- 2 (2.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eICP monitoring system, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (15.2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eClinical setting\u003c/p\u003e \u003cp\u003e- Neurology wards (Stroke Unit \u0026amp; general)\u003c/p\u003e \u003cp\u003e- ICU (neurological \u0026amp; cardiological)\u003c/p\u003e \u003cp\u003e- Angio Suite (cardiological \u0026amp; neurological)\u003c/p\u003e \u003cp\u003e- Operating Room\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e- 56 (60.9)\u003c/p\u003e \u003cp\u003e- 30 (32.6)\u003c/p\u003e \u003cp\u003e- 5 (5.4)\u003c/p\u003e \u003cp\u003e- 1 (1.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eAbbreviations. IQR: interquartile range; n: number; SAH: subarachnoid hemorrhage; ICH: intracerebral hemorrhage; PRES: posterior reversible encephalopathy syndrome; ECMO: extracorporeal membrane oxygenation; ICP: intracerebral pressure; ICU: intensive care unit\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eFeasibility and safety\u003c/h2\u003e \u003cp\u003eThe exam was feasible in the majority of our patients (85.9%), as reported in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. In nine patients (9.7%) the ra-TCD was not feasible because of individual head or neck anatomy (eg. short neck) that impeded correct positioning of the device. Moreover, in 2 out of 14 patients with an ICP monitoring system the exam could not be performed because the intracranial probe hindered the position of the head cradle. Ra-TCD was feasible in all five patients with ECMO. Continuous cerebral monitoring with ra-TCD was possible in all patients undergoing cardiological interventional procedures (four patients), however it could not be performed during mechanical thrombectomy, since the ultrasound probes are radio-opaque, thus interfering with the necessary radioscopic imaging performed during the procedure. Lastly, ra-TCD was not feasible in the patient undergoing surgical carotid endarterectomy, since the head cradle interfered with the access to the surgical site.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eExam feasibility and safety\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNumber of patients\u0026thinsp;=\u0026thinsp;92\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eFeasibility\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eRa-TCD overall feasibility, n (%)\u003c/p\u003e \u003cp\u003e- Neurology wards (Stroke Unit, general)\u003c/p\u003e \u003cp\u003e- ICU (neurological \u0026amp; cardiological)\u003c/p\u003e \u003cp\u003e- Angio Suite (cardiological \u0026amp; neurological)\u003c/p\u003e \u003cp\u003e- Operating Room\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e79 (85.9)\u003c/p\u003e \u003cp\u003e- 49/56 (87.5)\u003c/p\u003e \u003cp\u003e- 26/30 (86.7)\u003c/p\u003e \u003cp\u003e- 4/5 (80)\u003c/p\u003e \u003cp\u003e- 0/1 (0)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCauses of non-feasibility, n (%)\u003c/p\u003e \u003cp\u003e- Head or neck anatomy, n (%)\u003c/p\u003e \u003cp\u003e- ICP monitoring device localization, n (%)\u003c/p\u003e \u003cp\u003e- Obstruction to surgical procedures, n (%)\u003c/p\u003e \u003cp\u003e- Non-radiopacity (for EVT), n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (14.1)\u003c/p\u003e \u003cp\u003e- 9 (9.7)\u003c/p\u003e \u003cp\u003e- 2 (2.2)\u003c/p\u003e \u003cp\u003e- 1 (1.1)\u003c/p\u003e \u003cp\u003e- 1 (1.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFeasibility with ECMO (n\u0026thinsp;=\u0026thinsp;5), n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5/5 (100)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFeasibility with ICP monitoring device (n\u0026thinsp;=\u0026thinsp;14), n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12/14 (86)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eSafety\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMajor complications, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMinor complications, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (1.1)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eAbbreviations. Ra-TCD: Robotic assisted-TCD; n: Number; ICU: Intensive Care Unit; ICP: intracerebral pressure; EVT: endovascular treatment; ECMO: extracorporeal membrane oxygenation.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eA minor complication was reported only in one patient (1.1%), namely a localized, self-limiting and quickly resolving subcutaneous edema due to mechanical pressure of the TCD probe positioned on the temporal bone window. This complication did not constitute a matter of concern.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eDetection rates and time intervals\u003c/h2\u003e \u003cp\u003eAmong those 79 patients in whom the examination was feasible, ra-TCD automatically identified an optimal MCA signal in 124 out of 158 (78.5%) temporal bone windows, with a median detection time of 2 minutes and 18 seconds. Hence, in this study, ra-TCD showed a good overall rate of autonomous MCA detection (78.5%), in agreement with studies conducted among adults of all ages.\u003csup\u003e\u003cspan additionalcitationids=\"CR20\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e When MCA signal was not automatically detected within 15 minutes of search, manual search mode led to the identification of 9 additional MCA Doppler signals, increasing the overall detection rate to 84.2%.\u003c/p\u003e \u003cp\u003eThe median time of ra-TCD monitoring was 34 minutes. Seven (8.9%) exams were interrupted earlier due to the patient's discomfort (6.3%) or acute clinical events (cardiac arrest, severe agitation) (2.6%) requiring urgent medical intervention (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eExam specifics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003eNumber of patients\u0026thinsp;=\u0026thinsp;79\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTime of set-up, median (min-max)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e13.5 mins (5.1\u0026ndash;21.3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTime needed to detect MCA, median (min-max)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e2.3 mins (0.1\u0026ndash;14.5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAutomatic signal detection rate, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e124/158 (78.5%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMCA signal detection rate with manual intervention, n (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e133/158 (84.2%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDuration of TCD monitoring, median (min-max)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e34 mins (9-150)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEarly interruption of the exam due to:\u003c/p\u003e \u003cp\u003e- Patient\u0026rsquo;s discomfort\u003c/p\u003e \u003cp\u003e- Medical emergencies\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003e7/79 (8.9%)\u003c/p\u003e \u003cp\u003e- 5/79 (6.3%)\u003c/p\u003e \u003cp\u003e- 2/79 (2.6%)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePSV difference (Ra-TCD vs manual TCD), median (min-max)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e+\u0026thinsp;8.8 cm/s (-6.8 - +18.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.891\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEDV difference (Ra-TCD vs manual TCD), median (min-max)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e+\u0026thinsp;6.8 cm/s (-4.1 - +7.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003ep\u0026thinsp;=\u0026thinsp;0.671\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e \u003cp\u003eAbbreviations. Min: minimum; Max: maximum; MCA: Middle Cerebral Artery; N: number; PSV: Peak Systolic Velocity; EDV: End Diastolic Velocity.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eVelocity comparison between ra-TCD and manual TCD\u003c/h2\u003e \u003cp\u003eAmong those 79 patients in whom ra-TCD was feasibile, we compared PSV and EDV values of the MCA obtained with ra-and manual TCD. The median difference between ra-TCD and manual TCD was +\u0026thinsp;8.8 cm/s (min-max: -6.8 - +18.1) for PSV and +\u0026thinsp;6.8 cm/s (min-max: -4.1 - +7.1) for EDV, i.e. not statistically significant (p\u0026thinsp;=\u0026thinsp;0.891 for PSV and 0.671 for EDV).\u003c/p\u003e \u003c/div\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eRobotically assisted devices in medicine represent a promising field that has been only partially applied to clinical practice. Initial evidence regarding the application of ra-TCD for a single-shot examination has been reported for instance by a multicenter study comparing ra-TCD and transthoracic echocardiogram for right-to-left shunt detection in stroke patients suggesting ra-TCD to be more effective.\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e However, our study is the first to show that this new ra-TCD system allows to easily monitor cerebral hemodynamics in different hospital settings.\u003c/p\u003e \u003cp\u003eFeasibility in our population was remarkably high overall. Intensive care patients could be monitored for a few hours despite the presence of different invasive equipment such as endotracheal tube, tracheostomy and ECMO. In patients with an ICP probe the examination could be completed in most cases, except for two with a posterior site of insertion of the intracranial probe. Our study is the largest to date testing ra-TCD in the intensive care setting, confirming preliminary data of a study on 12 patients with subarachnoid hemorrhage that showed safety and efficacy of the same device.\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e Due to its numerous applications, TCD has also been described as the \u0026ldquo;stethoscope of the brain\u0026rdquo; for critically ill patients.\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e In fact, it easily allows an early identification of cerebral hemodynamic alterations, such as vasospasm, altered cerebral autoregulation, pulsatility index rise thus guiding clinical management. Ra-TCD, being operator-independent, might further boost this technique allowing prolonged monitoring of cerebral hemodynamics, thus becoming an integral part of neuromonitoring.\u003c/p\u003e \u003cp\u003eThe highest feasibility was demonstrated in the stroke unit and the general neurological ward, with only a minority of cases where the examination was impeded by uncommon anatomical characteristics of patients. This preliminary data opens the field to the potential application of continuous monitoring of cerebral hemodynamics in ischemic stroke patients, for example after thrombectomy, where flow parameters in the recanalized vessel have shown to correlate with prognosis.\u003csup\u003e\u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e Another possible application of ra-TCD is the prolonged monitoring of MCA signal in patients with asymptomatic carotid artery stenosis, where the detection of MES in the ipsilateral MCA significantly increases the risk to develop ischemic stroke.\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e Prolonged monitoring would raise the chances of MES detection and help identify atherosclerotic plaques at higher risk of distal embolization.\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eConcerning the comparison of blood flow velocities among ra-TCD and manual TCD, our study did not find any statistical difference. No real-world studies are available in literature comparing ra-TCD and manual TCD. However, since the device we utilized employs an already validated and widely tested TCD we think these results reinforce the validity of ra-ultrasound devices and their potential to expand hemodynamics monitoring in neurovascular patients.\u003c/p\u003e \u003cp\u003eRegarding TCD-related complications, only one patient reported moderate transient unilateral subcutaneous edema in the temporal region due to the probe\u0026rsquo;s mechanical pressure. The edema regressed quickly and spontaneously right after the end of the examination, and it was not considered a matter of concern by the authors. Nonetheless, it would be advisable to reduce the probe pressure on the temple. No similar reports are available in the literature, although the experience is scant so far. A previous study performing \u003cem\u003enon-monitoring\u003c/em\u003e TCD examinations in 129 patients proved the device to be safe. Specifically, no serious adverse events were reported, while only two non-serious events were documented both unrelated to the device.\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eTCD is a unique tool in detecting microemboli entering the MCA during heart surgery and cardiologic procedures, although the clinical relevance of these findings is still debated.\u003csup\u003e\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e,\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e In our study, prolonged TCD monitoring was easily performed during cardiological interventional procedures, opening the field for exploration of cerebral hemodynamic parameters and MES detection in this very interesting setting. On the other hand, ra-TCD was not feasible during neurological interventional procedures such as acute mechanical thrombectomy and carotid stenting, because the probes were radiopaque, not allowing patients to undergo intraprocedural radiological checks. An updated version of the ra-TCD with radiotransparent probes has been recently released, but it needs to be re-evaluated in this setting. Ra-TCD was also not feasible during open carotid surgery, because the size of the device interfered with the surgical field. This is a drawback, as detection of MES during CEA showed a significant relationship with perioperative cerebral complications and new ischemic lesions in different studies.\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e,\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e Ra-TCD has a great potential as it could be applied to study the risk of perioperative cerebral complications after different kinds of surgery (eg. orthopedic surgery), expanding the data of first explorative reports.\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eAltogether, the results of the current study show the need for further technological advancement to perform operator-independent monitoring of cerebral hemodynamics and guide the improvement of cardiovascular or neurovascular procedures to reduce stroke burden.\u003c/p\u003e"},{"header":"CONCLUSIONS","content":"\u003cp\u003eTo conclude, this novel ra-TCD was found to be a safe and feasible bedside tool for real-time monitoring of cerebral hemodynamics. Blood flow velocities do not differ significantly between ra-TCD and manual TCD. Further technical improvements are needed to expand the range of its applicability, allowing to systematically perform prolonged hemodynamics monitoring in neurovascular patients.\u003c/p\u003e"},{"header":"Declarations","content":"\u003col\u003e\n \u003cli\u003eThe authors confirm that this manuscript complies with all \u0026ldquo;instructions to authors\u0026rdquo;.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eThe authors confirm that authorship requirements have been met and the final manuscript was approved by all authors.\u0026nbsp;\u003c/li\u003e\n\u003c/ol\u003e\n\u003col\u003e\n \u003cli\u003eThe authors confirm that this manuscript has not been published elsewhere and is not under consideration by another journal. \u0026nbsp;\u003c/li\u003e\n \u003cli\u003eThe study was approved by the Research Ethics Committees of both centers and informed consent was obtained from all individual participants included.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eFUNDING: this study was not supported by any funding.\u003c/li\u003e\n \u003cli\u003eDISCLOSURES: The authors have no disclosures for this study.\u003c/li\u003e\n \u003cli\u003eACKNOWLEDGMENTS\u003cstrong\u003e:\u0026nbsp;\u003c/strong\u003enone.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/li\u003e\n\u003c/ol\u003e\n\u003cp\u003e\u003cstrong\u003eAUTHORS CONTRIBUTIONS:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cul\u003e\n \u003cli\u003eFattorello Salimbeni Alvise: Conceptualization, Methodology, Neurosonological evaluation, Formal analysis, Data Curation, Writing - Original Draft.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eKulyk Caterina: Conceptualization, Methodology, Neurosonological evaluation, Formal analysis, Data Curation, Writing - Original Draft.\u003c/li\u003e\n \u003cli\u003eFavruzzo Francesco: Neurosonological evaluation, Writing - Original Draft.\u003c/li\u003e\n \u003cli\u003eDe Rosa Ludovica: Neurosonological evaluation, Formal analysis, Data Curation.\u0026nbsp;\u003c/li\u003e\n \u003cli\u003eViaro Federica: Neurosonological evaluation, Formal analysis, Data Curation.\u003c/li\u003e\n \u003cli\u003ePieroni Alessio: Neurosonological evaluation, Formal analysis, Data Curation.\u003c/li\u003e\n \u003cli\u003eMozzetta Stefano: Neurosonological evaluation, Formal analysis, Data Curation.\u003c/li\u003e\n \u003cli\u003eVosko R Milan: Writing - Review \u0026amp; Editing, Supervision, Project administration.\u003c/li\u003e\n \u003cli\u003eBaracchini Claudio: Writing - Review \u0026amp; Editing, Supervision, Project administration.\u0026nbsp;\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eRoh D, Park S. Brain multimodality monitoring: updated perspectives. Curr Neurol Neurosci Rep 2016;16:56. https://doi.org/10.1007/s11910-016-0659-0.\u003c/li\u003e\n\u003cli\u003eAaslid R, Markwalder TM, Nornes H. Noninvasive transcranial Doppler ultrasound recording of flow velocity in basal cerebral arteries. J Neurosurg 1982; 57:769-774. https://doi.org/10.3171/jns.1982.57.6.0769. \u003c/li\u003e\n\u003cli\u003eRobba C, Goffi A, Geeraerts T, et al. Brain ultrasonography: methodology, basic and advanced principles and clinical applications. A narrative review. Intensive Care Med 2019;45:913-927. https://doi.org/10.1007/s00134-019-05610-4. \u003c/li\u003e\n\u003cli\u003eRodriguez CN, Baracchini C, Mantilla JHM et al. Neurosonology in critical care: monitoring the neurological impact of the critical pathology. Cham, Switzerland: Springer Nature Switzerland; 2022:1149. \u003c/li\u003e\n\u003cli\u003eLindegaard KF, Nornes H, Bakke SJ, Sorteberg W, Nakstad P. Cerebral vasospasm diagnosis by means of angiography and blood velocity measurements. Acta Neurochir 1989;100:12-24. https://doi.org/10.1007/BF01405268.\u003c/li\u003e\n\u003cli\u003eRussell D. The detection of cerebral emboli using doppler ultrasound. In: Newell DW and Aaslid R, ed. Transcranial Doppler. New York, NY: Raven Press Publishers; 2017:207-213. https://doi.org/10.1515/bmte.1999.44.4.87. \u003c/li\u003e\n\u003cli\u003eRingelstein EB, Droste DW, Babikian VI et al. Consensus on microembolus detection by TCD. Stroke 1998;29:725-729. https://doi.org/10.1161/01.str.29.3.725.\u003c/li\u003e\n\u003cli\u003eKing A, Markus HS. Doppler embolic signals in cerebrovascular disease and prediction of stroke risk: a systematic review and meta-analysis. Stroke 2009;40:3711-7. https://doi.org/10.1161/STROKEAHA.109.563056.\u003c/li\u003e\n\u003cli\u003eStygall J, Kong R, Walker JM et al. Cerebral microembolism detected by transcranial Doppler during cardiac procedures. Stroke 2000;31:2508-10. https://doi.org/10.1161/01.str.31.10.2508.\u003c/li\u003e\n\u003cli\u003eDittrich R, Ringelstein EB. Occurrence and clinical impact of microembolic signals during or after cardiosurgical procedures. Stroke 2008;39:503-11. https://doi.org/10.1161/STROKEAHA.107.491241.\u003c/li\u003e\n\u003cli\u003eAckerstaff RG, Jansen C, Moll FL et al. The significance of microemboli detection by means of transcranial Doppler ultrasonography monitoring in carotid endarterectomy. J Vasc Surg 1995;21:963-9. https://doi.org/10.1016/s0741-5214(95)70224-5.\u003c/li\u003e\n\u003cli\u003eCardim D, Robba C, Schmidt E et al. Transcranial Doppler Non-invasive Assessment of Intracranial Pressure, Autoregulation of Cerebral Blood Flow and Critical Closing Pressure during Orthotopic Liver Transplant. Ultrasound in medicine \u0026amp; biology 2019;45(6):1435-1445. https://doi.org/10.1016/j.ultrasmedbio.2019.02.003.\u003c/li\u003e\n\u003cli\u003eUdesh R, Natarajan P, Thiagarajan K et al. Transcranial doppler monitoring in carotid endarterectomy: a systematic review and meta-analysis. J Ultrasound Med 2017;36:621-630. https://doi.org/10.7863/ultra.16.02077.\u003c/li\u003e\n\u003cli\u003eGelormini C, Ioannoni E, Scavone A et al. Hyperemia in head injury: can transcranial doppler help to personalize therapies for intracranial hypertension? Front Neurol 2023;14:1259180. https://doi.org/10.3389/fneur.2023.1259180.\u003c/li\u003e\n\u003cli\u003eRobba C, Taccone FS. How I use Transcranial Doppler. Crit Care 2019;23:420. doi:10.1186/s13054-019-2700-6.\u003c/li\u003e\n\u003cli\u003eMart\u0026iacute;nez-Palacios K, V\u0026aacute;squez-Garc\u0026iacute;a S, Fariyike OA et al. Non-Invasive Methods for Intracranial Pressure Monitoring in Traumatic Brain Injury Using Transcranial Doppler: A Scoping Review. Journal of neurotrauma 2024;10.1089/neu.2023.0001. https://doi.org/10.1089/neu.2023.0001.\u003c/li\u003e\n\u003cli\u003eBaracchini C, Azevedo E, Walter U et al. Neurosonology survey in Europe and beyond. Ultrasound International Open 2024; 10:a22439625. https://doi.org/10.1055/a-2243-9625.\u003c/li\u003e\n\u003cli\u003eO\u0026rsquo;Brien MJ, Dorn AY, Ranjbaran M et al. Fully automated transcranial doppler ultrasound for middle cerebral artery insonation. J Neurosonol Neuroimag 2022;14:27-34. https://doi.org/10.31728/jnn.2021.00110.\u003c/li\u003e\n\u003cli\u003eItoh T, Matsumoto M, Handa N et al. Rate of successful recording of blood flow signals in the middle cerebral artery using transcranial Doppler sonography. Stroke 1993;24:1192-5. https://doi.org/10.1161/01.str.24.8.1192.\u003c/li\u003e\n\u003cli\u003eWijnhoud AD, Franckena M, van der Lugt A et al. Inadequate acoustical temporal bone window in patients with a transient ischemic attack or minor stroke: role of skull thickness and bone density. Ultrasound Med Biol 2008;34:923-9. https://doi.org/10.1016/j.ultrasmedbio.2007.11.022.\u003c/li\u003e\n\u003cli\u003eHe L, Wu DF, Zhang JH et al. Factors affecting transtemporal window quality in transcranial sonography. Brain Behav 2022;12:e2543. doi:10.1002/brb3.2543.\u003c/li\u003e\n\u003cli\u003eRubin MN, Shah R, Devlin T et al. Robot-assisted transcranial doppler versus transthoracic echocardiography for right to left shunt detection. Stroke 2023;54:2842-2850. https://doi.org/10.1161/STROKEAHA.123.043380.\u003c/li\u003e\n\u003cli\u003eClare K, Stein A, Damodara N et al. Safety and efficacy of a novel robotic transcranial doppler system in subarachnoid hemorrhage. Sci Rep 2022;12: 2266. https://doi.org/10.1038/s41598-021-04751-1.\u003c/li\u003e\n\u003cli\u003eBaracchini C, Farina F, Palmieri A et al. Early hemodynamic predictors of good outcome and reperfusion injury after endovascular treatment. Neurology 2019;11:92. https://doi.org/10.1212/WNL.0000000000007646.\u003c/li\u003e\n\u003cli\u003eCastro P, Ferreira J, Malojcic B et al. Detection of microemboli in patients with acute ischaemic stroke and atrial fibrillation suggests poor functional outcome. Eur Stroke J 2023;23969873231220508. https://doi.org/10.1177/23969873231220508.\u003c/li\u003e\n\u003cli\u003eFarina F, Palmieri A, Favaretto S et al. Prognostic role of microembolic signals after endovascular treatment in anterior circulation ischemic stroke patients. World Neurosurg.2018;110:e882-e889. https://doi.org/10.1016/j.wneu.2017.11.120. \u003c/li\u003e\n\u003cli\u003eMarkus HS, King A, Shipley M et al. Asymptomatic embolisation for prediction of stroke in the Asymptomatic Carotid Emboli Study (ACES): a prospective observational study. Lancet Neurol 2010;9:663-71. https://doi.org/10.1016/S1474-4422(10)70120-4.\u003c/li\u003e\n\u003cli\u003eSpence JD, Tamayo A, Lownie SP et al. Absence of microemboli on transcranial Doppler identifies low-risk patients with asymptomatic carotid stenosis. Stroke 2005;36:2373-8. https://doi.org/10.1161/01.STR.0000185922.49809.46.\u003c/li\u003e\n\u003cli\u003eSilbert BS, Evered LA, Scott DA et al. Review of transcranial Doppler ultrasound to detect microemboli during orthopedic surgery. Am J Neuroradiol 2014;35:1858-63. https://doi.org/10.3174/ajnr.A3688.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"neurocritical-care","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"neca","sideBox":"Learn more about [Neurocritical Care](http://link.springer.com/journal/12028)","snPcode":"12028","submissionUrl":"https://www.editorialmanager.com/neca/default2.aspx","title":"Neurocritical Care","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Transcranial ultrasound, neuromonitoring, cerebral hemodynamics, robotic, artificial intelligence, feasibility, safety","lastPublishedDoi":"10.21203/rs.3.rs-4545187/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4545187/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eIntroduction\u003c/strong\u003e: Transcranial Color Doppler (TCD) is currently the only non-invasive bedside tool capable of providing real-time information on cerebral hemodynamics. However, being operator dependent, TCD monitoring is not feasible in many institutions. Robotic assisted TCD (ra-TCD) was recently developed to overcome these constraints. The aim of this study was to evaluate the safety and feasibility of cerebral monitoring with a novel ra-TCD in acute neurovascular care.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: This is a two-center prospective study conducted between August 2021 and February 2022 at Padua University Hospital (Padua, Italy) and Kepler University Hospital (Linz, Austria). Adult patients with conditions impacting on cerebral hemodynamics or undergoing invasive procedures affecting cerebral hemodynamics were recruited for prolonged monitoring (\u0026gt; 30 minutes) of the middle cerebral artery (MCA) with a novel ra-TCD (NovaGuide\u003csup\u003eTM\u003c/sup\u003e Intelligent Ultrasound, NeuraSignal, Los Angeles, CA, USA). Manual TCD was also performed for comparison by an experienced operator. Feasibility and safety rates were recorded.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e: 92 patients [age: mean 68.5 years, range 36-91; gender: male 57 (62%)] were enrolled in the two centers: 54 in Padua, 38 in Linz. The exam was feasible in the majority of patients (85.9%); the head cradle design and its radiopacity hindered its use during carotid endarterectomy and mechanical thrombectomy. Regarding safety, only one patient (1.1%) reported a minor local edema due to prolonged probe pressure. Velocity values resulted similar between ra-TCD and manual TCD.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDiscussion\u003c/strong\u003e: This novel ra-TCD showed an excellent safety and feasibility, and proved to be as reliable as manual TCD in detecting blood flow velocities. These findings support its wider use for cerebral hemodynamics monitoring in acute neurovascular care. However, further technical improvements are needed to expand the range of applicable settings.\u003c/p\u003e","manuscriptTitle":"Robotic-Assisted Transcranial Doppler Monitoring in Acute Neurovascular Care: a Feasibility and Safety Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-07-16 22:15:33","doi":"10.21203/rs.3.rs-4545187/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2024-06-19T17:02:24+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2024-06-19T16:35:56+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Neurocritical Care","date":"2024-06-12T18:18:01+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2024-06-11T18:32:34+00:00","index":"","fulltext":""},{"type":"submitted","content":"Neurocritical Care","date":"2024-06-10T16:45:11+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"neurocritical-care","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"neca","sideBox":"Learn more about [Neurocritical Care](http://link.springer.com/journal/12028)","snPcode":"12028","submissionUrl":"https://www.editorialmanager.com/neca/default2.aspx","title":"Neurocritical Care","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"5e625ed6-62fe-4e86-9eb9-ad4000662eec","owner":[],"postedDate":"July 16th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2024-09-27T10:46:37+00:00","versionOfRecord":{"articleIdentity":"rs-4545187","link":"https://doi.org/10.1007/s12028-024-02121-z","journal":{"identity":"neurocritical-care","isVorOnly":false,"title":"Neurocritical Care"},"publishedOn":"2024-09-19 15:58:05","publishedOnDateReadable":"September 19th, 2024"},"versionCreatedAt":"2024-07-16 22:15:33","video":"","vorDoi":"10.1007/s12028-024-02121-z","vorDoiUrl":"https://doi.org/10.1007/s12028-024-02121-z","workflowStages":[]},"version":"v1","identity":"rs-4545187","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4545187","identity":"rs-4545187","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}