Monitoring Of Cerebral Perfusion Research Articles

The Role of Continuous Monitoring of Venous Drainage Flow and Integrated Oxygen Extraction (ERiO2) via Bilateral Near-Infrared Spectroscopy in Cerebral Perfusion During Aortic Arch Surgery

Background and Objective: Effective cerebral perfusion monitoring is essential in aortic arch surgery, particularly when employing the Kazui technique under moderate hypothermia. Near-infrared spectroscopy (NIRS) provides real-time regional oxygen saturation (rSO2) measurements, while the continuous monitoring of venous drainage flow and oxygen extraction ratio (ERiO2) delivers additional insights into cerebral oxygenation and metabolic balance. This study investigates the correlation between NIRS-derived rSO2, venous drainage flow, and ERiO2 during selective antegrade cerebral perfusion (SACP) to better understand their interplay and clinical significance. Materials and Methods: This retrospective study analyzed data from 10 patients undergoing aortic arch surgery with the Kazui technique, including 4 patients with type I A dissections and 6 with aortic arch aneurysms. Bilateral NIRS (Masimo system) was used to measure rSO2, while venous drainage flow and ERiO2 were continuously monitored using the Landing system. Intraoperative parameters such as cardiopulmonary bypass (CPB) time, cooling and rewarming duration, venous return flow, and perfusion delivery rates were collected and analyzed. The correlations between rSO2, venous drainage flow, and ERiO2 were statistically evaluated. Results: The mean CPB time was 182 ± 15 min, with a mean cross-clamp time of 98 ± 12 min. Cooling to 20 °C was achieved in 29 ± 3 min, followed by a controlled rewarming phase of 10 ± 1.5 min. The venous return flow averaged 570 ± 25 mL/min, while the perfusion delivery rates exceeded 600 ± 30 mL/min. Bilateral NIRS monitoring revealed stable rSO2 values averaging 65 ± 5%, while ERiO2 averaged 28 ± 4%. A strong correlation (r = 0.91, p < 0.01) was observed between rSO2 and ERiO2, with venous drainage flow playing a critical role in maintaining this relationship. Conclusions: This study demonstrates a robust correlation between NIRS-derived rSO2, continuous venous drainage flow, and ERiO2 during SACP in aortic arch surgery.

Perioperative Craniotomy Excision of Dextra Subtemporal Tumor with Thiopental, Sufentanyl and Invasive Monitor

Intracranial masses can arise from a variety of aetiologies, including congenital, neoplastic, infectious, or vascular processes, each requiring distinct diagnostic and management considerations. Establishing the presence or absence of intracranial hypertension is a critical component of the preoperative evaluation for patients undergoing craniotomy for mass lesions. Hemodynamic is an examination of the physical aspects of blood circulation, cardiac function and physiological characteristics of peripheral vasculature. A 74 year old man was admitted to the hospital because of cephalgia, and left limb weakness. Previously, the patient often felt headaches that came and went since six months ago. Three days before being admitted, the patient felt weak in his left limb and experienced decreasing in consciousness. The patient was given thiopental because the onset of action of thiopental was very short. Administration of intravenous doses of thiopental can cause cerebral vasoconstriction. Sufentanil was administered as an analgesic, because sufentanil is an opioid that has a rapid onset and analgesic potential, compared to fentanyl, intravenous and sufentanil is 5–10 times stronger. This efficacy to maintain adequate cerebral perfusion pressure (CPP), reduce cerebral blood flow (CBF), maintain normal autoregulation, reduce cerebral metabolic rate for oxygen (CMRO2). Arterial cannulation with continuous transduction is considered the gold standard for blood pressure monitoring during anaesthetic procedures. Rapid fluctuations in blood pressure can occur due to patient positioning, surgical manipulation, and the effects of anaesthetics drugs, and close monitoring of these changes is crucial for maintaining hemodynamic stability. The impact of anaesthetic management on CBF is also an integral component of neuroanesthesia, as increases in CBF are associated with increases in cerebral blood volume (CBV). An effective neuro-anesthesia management program that incorporates both invasive blood pressure monitoring and optimization of cerebral perfusion that can help preserving hemodynamic stability and improving outcomes for patients undergoing craniotomy surgery

A preliminary study on the application of electrical impedance tomography based on cerebral perfusion monitoring to intracranial pressure changes.

In intracranial pathologic conditions of intracranial pressure (ICP) disturbance or hemodynamic instability, maintaining appropriate ICP may reduce the risk of ischemic brain injury. The change of ICP is often accompanied by the change of intracranial blood status. As a non-invasive functional imaging technique, the sensitivity of electrical impedance tomography (EIT) to cerebral hemodynamic changes has been preliminarily confirmed. However, no team has conducted a feasibility study on the dynamic detection of ICP by EIT technology from the perspective of non-invasive whole-brain blood perfusion monitoring. In this study, human brain EIT image sequence was obtained by in vivo measurement, from which a variety of indicators that can reflect the tidal changes of the whole brain impedance were extracted, in order to establish a new method for non-invasive monitoring of ICP changes from the level of cerebral blood perfusion monitoring. Valsalva maneuver (VM) was used to temporarily change the cerebral blood perfusion status of volunteers. The electrical impedance information of the brain during this process was continuously monitored by EIT device and real-time imaging was performed, and the hemodynamic indexes of bilateral middle cerebral arteries were monitored by transcranial Doppler (TCD). The changes in monitoring information obtained by the two techniques were compared and observed. The EIT imaging results indicated that the image sequence showed obvious tidal changes with the heart beating. Perfusion indicators of vascular pulsation obtained from EIT images decreased significantly during the stabilization phase of the intervention (PAC: 242.94 ± 100.83, p < 0.01); perfusion index which reflects vascular resistance increased significantly in the stable stage of intervention (PDT: 79.72 ± 18.23, p < 0.001). After the intervention, the parameters gradually returned to the baseline level before compression. The changes of EIT indexes in the whole process are consistent with the changes of middle cerebral artery velocity related indexes shown in TCD results. The EIT image combined with the blood perfusion index proposed in this paper can reflect the decrease of cerebral blood flow under the condition of increased ICP in real time and intuitively. With the advantages of high time resolution and high sensitivity, EIT provides a new idea for non-invasive bedside measurement of ICP.

Comparing the performance potential of speckle contrast optical spectroscopy and diffuse correlation spectroscopy for cerebral blood flow monitoring using Monte Carlo simulations in realistic head geometries.

The non-invasive measurement of cerebral blood flow based on diffuse optical techniques has seen increased interest as a research tool for cerebral perfusion monitoring in critical care and functional brain imaging. Diffuse correlation spectroscopy (DCS) and speckle contrast optical spectroscopy (SCOS) are two such techniques that measure complementary aspects of the fluctuating intensity signal, with DCS quantifying the temporal fluctuations of the signal and SCOS quantifying the spatial blurring of a speckle pattern. With the increasing interest in the use of these techniques, a thorough comparison would inform new adopters of the benefits of each technique. We systematically evaluate the performance of DCS and SCOS for the measurement of cerebral blood flow. Monte Carlo simulations of dynamic light scattering in an MRI-derived head model were performed. For both DCS and SCOS, estimates of sensitivity to cerebral blood flow changes, coefficient of variation of the measured blood flow, and the contrast-to-noise ratio of the measurement to the cerebral perfusion signal were calculated. By varying complementary aspects of data collection between the two methods, we investigated the performance benefits of different measurement strategies, including altering the number of modes per optical detector, the integration time/fitting time of the speckle measurement, and the laser source delivery strategy. Through comparison across these metrics with simulated detectors having realistic noise properties, we determine several guiding principles for the optimization of these techniques and report the performance comparison between the two over a range of measurement properties and tissue geometries. We find that SCOS outperforms DCS in terms of contrast-to-noise ratio for the cerebral blood flow signal in the ideal case simulated here but note that SCOS requires careful experimental calibrations to ensure accurate measurements of cerebral blood flow. We provide design principles by which to evaluate the development of DCS and SCOS systems for their use in the measurement of cerebral blood flow.

Evaluation and Management of Traumatic Brain Injuries in the Pediatric Intensive Care Unit.

In this overview, intended for a multidisciplinary readership, we address the challenges in early management of children who have sustained mild, moderate, or severe traumatic brain injuries. Pediatric traumatic brain injuries (pTBIs) present unique diagnostic and management challenges as compared with adults. Proper management requires careful interpretation of data and strong clinical judgment. Children with injuries due to nonaccidental trauma present unique diagnostic and management challenges. In the pediatric intensive care unit, care is provided as part of a multidisciplinary, collaborative team, with medical and surgical interventions tailored to injury severity. Intensive care focuses on managing cerebral perfusion, temperature, mechanical ventilation, and continuous EEG monitoring to mitigate secondary brain injury. Long-term recovery emphasizes multidisciplinary rehabilitation and support to address physical, cognitive, and emotional challenges.

Multimodal monitoring of cerebral perfusion in carotid endarterectomy patients: a computational fluid dynamics study.

To evaluate postoperative cerebral perfusion changes and their influencing factors in carotid endarterectomy (CEA) patients by integrating multimodal monitoring methods, including cerebral regional oxygen saturation (rSO2), carotid ultrasound (CU), computed tomographic angiography (CTA), and computed tomographic perfusion imaging (CTP), with computational fluid dynamics (CFD) assessment. We conducted a cohort study on patients with internal carotid artery (ICA) stenosis undergoing CEA at our institution. Pre- and postoperative assessments included CU, CTA, CTP, and rSO2 monitoring. Hemodynamic parameters recorded were mean flow velocity (MFV), peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI), rSO2, and cerebral blood flow (CBF). CFD quantified the total pressure (TP), wall shear stress (WSS), wall shear stress ratio (WSSR), and translesional pressure ratio (PR) of the ICA. Pearson correlation was used to analyze factors influencing cerebral perfusion changes. Multivariate logistic regression identified risk factors for cerebral hyperperfusion (CH). The predictive value of multimodal and single-modality monitoring for CH was evaluated using ROC curve analysis. Fifty-six patients were included, with nine developing postoperative CH. CU showed significant reductions in MFV, PSV, EDV, and RI of the ICA (p < 0.001). Ipsilateral rSO2 increased significantly (p = 0.013), while contralateral rSO2 showed no significant change (p = 0.861). CFD revealed significant decreases in TP, WSS, and WSSR (p < 0.001), along with a significant increase in PR (p < 0.001). Pearson analysis indicated that change rate of CBF (ΔCBF) positively correlated with ΔPR and ΔrSO2, and negatively correlated with ΔTP, ΔWSS, and Δ WSSR. Multivariate logistic regression identified preoperative WSSR (pre-WSSR) and ΔPR as risk factors for CH following CEA. Combined ΔPR, ΔrSO2, ΔMFV, and pre-WSSR had higher sensitivity and specificity than single-modality monitoring for predicting CH. CFD-based multimodal monitoring effectively identified cerebral perfusion changes and risk factors for CH in CEA patients, with superior predictive accuracy compared to single-modality methods. Nevertheless, further validation is necessary to establish its clinical utility.

Aspects of the formation of encephalopathy and myocardiopathy in sepsis

Relevance. The severe brain damage in most cases leads the patient to a long-term chronic critical condition (CCS). Regardless of the underlying disease that led to CCS, patients will have a certain imbalance of neurohumoral regulation and characteristic cognitive, muscle-reflex disorders. This cohort of patients is characterized not only by a cascade of typical pathological processes in the brain, but also by the consistent involvement of the cardiovascular system, respiratory organs, digestive organs, water metabolism, hormonal regulation, immunity, the addition of infectious-septic complications closes the circle of pathological processes, which often leads to death. Materials and methods. The search for domestic publications was carried out in the database on the RSCI website, foreign – in the PubMed, Google Scholar databases in the period 2000–2023. When analyzing the PubMed database, the query «sepsis neuroinflammation» found 5272 links. We also studied works on the following keywords: «neurotransmitters and sepsis». Publications describing the clinical picture, diagnosis, and sepsis were analyzed. A total of 40 articles were analyzed Such systems as immune, nervous and endocrine are interconnected due to regulatory peptides. Stable functioning of the central nervous system (CNS), or rather adequate secretion of neuropeptides are necessary for a normal immune response. Neuronal anti-inflammatory regulation of tissue macrophages is characterized by a local, rapid response to the pathogen through neuromediators.Confirmation of the neuropeptide theory of immunity regulation is the verification of neuropeptide receptors on peripheral blood lymphocytes and monocytes. These results indicate a possible mechanism of a «vicious» circle that occurs in infectious-septic complications and leads to damage to vital organs.To date, there are no widely available means for accurate monitoring of brain function at the patient’s bedside. There is no evidence or recommendations to support monitoring of cerebral perfusion or function in sepsis patients. At the same time, modern research on the phenotyping of patients taking into account brain dysfunction (sepsis associated encephalopathy) is based on the basic postulates of the pathophysiology and biochemistry of sepsis, but does not offer any methods of instrumental diagnosis of this condition, except for the use of validated delirium, coma scales (Glasgow coma scale, FOUR, CAM-ICU, etc.). Despite the described pathogenesis, there is currently no single definition of cardiac cardiomyopathy. However, most authors describe the fundamental features of this pathology: acute reversible one- or two-ventricular systolic or diastolic dysfunction with reduced contractility, not due to coronary heart disease. Primary cellular myocardial dysfunction in sepsis can manifest in several ways, including impaired function of the left and/or right ventricles during systole or diastole, as well as with insufficient cardiac output (CO) and oxygen delivery. To explain the changes in myocardial contractility associated with sepsis, several mechanisms have been proposed taking into account the host response. Since most of the parameters of the echo signal depend on the conditions of the volemic status, the evaluation of the echo signal should be repeated at several time points and supplemented with the definition of cardiac biomarkers. Conclusion. Analyzing the literature data on sepsis-associated encephalopathy and septic cardiomyopathy, it is possible to judge the interconnectedness of these events indirectly through damage to neurons during infectious-septic complications. Especially neuro-humoral mechanisms of regulation of the response to an infectious agent should be evaluated in patients with CCS, not only relying on laboratory diagnostics, but also using instrumental methods of visualization of brain, heart, and kidney damage. Such methods include magnetic resonance imaging (MRI), electroencephalogram (EEG), cerebral oximetry (CMRO2), echocardiography, ultrasound examination of the kidneys, etc

Near-infrared spectroscopy monitoring of neonatal cerebrovascular reactivity: where are we now?

Cerebrovascular reactivity defines the ability of the cerebral vasculature to regulate its resistance in response to both local and systemic factors to ensure an adequate cerebral blood flow to meet the metabolic demands of the brain. The increasing adoption of near-infrared spectroscopy (NIRS) for non-invasive monitoring of cerebral oxygenation and perfusion allowed investigation of the mechanisms underlying cerebrovascular reactivity in the neonatal population, confirming important associations with pathological conditions including the development of brain injury and adverse neurodevelopmental outcomes. However, the current literature on neonatal cerebrovascular reactivity is mainly still based on small, observational studies and is characterised by methodological heterogeneity; this has hindered the routine application of NIRS-based monitoring of cerebrovascular reactivity to identify infants most at risk of brain injury. This review aims (1) to provide an updated review on neonatal cerebrovascular reactivity, assessed using NIRS; (2) to identify critical points that need to be addressed with targeted research; and (3) to propose feasibility trials in order to fill the current knowledge gaps and to possibly develop a preventive or curative approach for preterm brain injury. IMPACT: NIRS monitoring has been largely applied in neonatal research to assess cerebrovascular reactivity in response to blood pressure, PaCO2 and other biochemical or metabolic factors, providing novel insights into the pathophysiological mechanisms underlying cerebral blood flow regulation. Despite these insights, the current literature shows important pitfalls that would benefit to be addressed in a series of targeted trials, proposed in the present review, in order to translate the assessment of cerebrovascular reactivity into routine monitoring in neonatal clinical practice.

Impact of cardiopulmonary bypass on cerebrovascular autoregulation assessed by ultrafast ultrasound imaging.

Newborns with congenital heart disease undergoing cardiac surgery are at risk of neurodevelopmental impairment with limited understanding of the impact of intra-operative cardiopulmonary bypass (CPB), deep hypothermia and selective cerebral perfusion on the brain. We hypothesized that a novel ultrasound technique, ultrafast power Doppler (UPD), can assess variations of cerebral blood volume (CBV) in neonates undergoing cardiac surgery requiring CPB. UPD was performed before, during and after surgery in newborns with hypoplastic left heart syndrome undergoing a Norwood operation. We found that global CBV was not significantly different between patients and controls (P=0.98) and between pre- and post-surgery (P=0.62). UPD was able to monitor changes in CBV throughout surgery, revealing regional differences in CBV during hypothermia during which CBV correlated with CPB flow rate (R2 =0.52, P=0.021). Brain injury on post-operative magnetic resonance imaging was observed in patients with higher maximum variation in CBV. Our findings suggest that UPD can quantify global and regional brain perfusion variation during neonatal cardiac surgery with this first intra-operative application demonstrating an association between CBV and CPB flow rate, suggesting loss of autoregulation. Therefore, the measurement of CBV by UPD could enable optimization of cerebral perfusion during cardiac surgery in neonates. KEY POINTS: The impact of cardiopulmonary bypass (CPB) on the neonatal brain undergoing cardiac surgery is poorly understood. Ultrafast power Doppler (UPD) quantifies cerebral blood volume (CBV), a surrogate of brain perfusion. CBV varies throughout CPB surgery and is associated with variation of the bypass pump flow rate during deep hypothermia. Association between CBV and bypass pump flow rate suggests loss of cerebrovascular autoregulatory processes. Quantitative monitoring of cerebral perfusion by UPD could provide a direct parameter to optimize CPB flow rate.

Monitoring of cerebral perfusion via oxygen partial pressure (ptiO2) measurement and near-field infrared spectroscopy (NIRS) in aneurysmatic subarachnoid haemorrhage

Monitoring of cerebral perfusion via oxygen partial pressure (ptiO2) measurement and near-field infrared spectroscopy (NIRS) in aneurysmatic subarachnoid haemorrhage

Espectroscopia no infravermelho próximo (NIRS) em unidade de terapia intensiva neonatal: experiência de um hospital universitário brasileiro

Near-infrared spectroscopy (NIRS) is a non-invasive method to assess regional brain and/or renal oxygenation, and an important tool for a better clinical management. The aim of this study was to describe clinical cases of newborns admitted to the Neonatal Intensive Care Unit of a Brazilian university hospital who were monitored with NIRS, and to evaluate the applicability of NIRS demonstrating its use as a continuous monitoring method for newborns at high risk for brain injury. This study was part of the Conclusion Work of Medical Residency in Neonatology in Neonatology. Case 1: Persistent ductus arteriosus-NIRS guided indication for drug treatment. Case 2: Septic shock-NIRS was helpful identifying the need of inotropes. Case 3: Anemia of prematurity-NIRS showed an increase of cerebral oxygenation after red blood cells transfusions. Case 4: Hypoxic-ischemic encephalopathy-NIRS identified sign of poor neurological prognostic. NIRS is a continuous cerebral and renal perfusion monitoring method that has easy and good applicability and no complications. The cases reflect the importance and potential of NIRS in clinical practice and in helping diagnose for newborns, as well as enabling prognostic assessment. NIRS proved to be a method of good applicability, without short-term complications. Observing brain oxygenation values can help to avoid conditions associated with the development of neurological sequelae.

Échographie préhospitalière et urgences cardiologiques

Technological advances over the past two decades have paved the way for the prehospital use of ultrasound. This practice was first developed in traumatology and then in a multitude of other indications, including cardiology. The development of pulmonary ultrasound is certainly the most visible illustration of this. Firstly, because it is an extra-cardiac examination that provides the answer to a cardiac question. Secondly because from a theoretical point of view this ultrasound indication was a bad indication for the use of ultrasound due to the air contained in the thorax. Thirdly, because this indication has become a ‘standard of care’ when caring for a patient with dyspnea – a practice that has become widespread during the COVID epidemic. In patients with heart failure, ultrasound has a high diagnostic power (including for alternative diagnoses) which is all the more precise since the technique is non-invasive, the response is obtained quickly, the examination can be repeated at desire to follow the evolution of the patient. The main other indications for prehospital ultrasound are cardiac arrest to search for a curable cause, identification of residual mechanical cardiac activity, monitoring of cerebral perfusion; chest pain, for both positive and negative diagnoses; shock for the search for an etiology and therapeutic follow-up or even pulmonary embolism or ultrasound for the search for dilation of the right ventricle which is now at the forefront of the recommendation algorithm.

An Update on Postoperative Cognitive Dysfunction Following Cardiac Surgery.

Postoperative cognitive dysfunction is extremely prevalent following cardiac surgery. The increasing patient age and comorbidity profile increases their susceptibility to cognitive impairment. The underlying pathophysiological mechanisms leading to cognitive impairment are not clearly elucidated. Using the contemporary literature (2015–present), this narrative review has three aims. Firstly, to provide an overview of postoperative cognitive impairment. Secondly, to analyse the predominant pathophysiological mechanisms leading to cognitive dysfunction following cardiac surgery such as inflammation, cerebral hypoperfusion, cerebral microemboli, glycaemic control and anaesthesia induced neurotoxicity. Lastly, to assess the current therapeutic strategies of interest to address these pathophysiological mechanisms, including the administration of dexamethasone, the prevention of prolonged cerebral desaturations and the monitoring of cerebral perfusion using near-infrared spectroscopy, surgical management strategies to reduce the neurological effects of microemboli, intraoperative glycaemic control strategies, the effect of volatile vs. intravenous anaesthesia, and the efficacy of dexmedetomidine.

Complete head cerebral sensitivity mapping for diffuse correlation spectroscopy using subject-specific magnetic resonance imaging models.

We characterize cerebral sensitivity across the entire adult human head for diffuse correlation spectroscopy, an optical technique increasingly used for bedside cerebral perfusion monitoring. Sixteen subject-specific magnetic resonance imaging-derived head models were used to identify high sensitivity regions by running Monte Carlo light propagation simulations at over eight hundred uniformly distributed locations on the head. Significant spatial variations in cerebral sensitivity, consistent across subjects, were found. We also identified correlates of such differences suitable for real-time assessment. These variations can be largely attributed to changes in extracerebral thickness and should be taken into account to optimize probe placement in experimental settings.

Savremeni tretman pacijenata sa karotidnom stenozom

Narrowing of the carotid arteries, carotid stenosis, (CS) is a frequent manifestation of atherosclerosis. It can be associated with other diseases of peripheral blood vessels, stenotic occlusive or aneurysmal, but also coronary arteries. Almost 15% of ischemic strokes are caused by this disease, which shares common risk factors with other atherosclerotic manifestations (age, male gender, hypertension, diabetes, smoking). The disease is progressive and with progression comes the progression of the degree of stenosis, the volume and morphological characteristics of the plaque. As these features progress, they increase the risk of clinical manifestations. Ischemic stroke, transient ischemic attack or transient blindness in the ipsilateral eye (amaurosis fugax) are the only clinical manifestations that can be directly related to carotid stenosis. Ischemic changes in the brain parenchyma, which can be seen on magnetic resonance imaging or computed tomography, are also associated with carotid stenosis. All the mentioned parameters are taken into account when making decisions about further treatment. Available drug therapy includes antiplatelet and statin therapy with control of risk factors (body weight correction, smoking cessation) and associated diseases (hypertension, diabetes, etc.). Invasive treatment includes carotid endarterectomy (CEA) as vascular or carotid stenting (CAS) as endovascular treatment. KEA is performed under local or general anesthesia, increasingly under local anesthesia, and after accessing the carotid arteries through a cervicotomy, they are clamped, the flow is interrupted, and after the artery is opened, plaque removal and endarterectomy are performed. In addition to the anesthesiological management of the patient and the performance of the surgical technique, the monitoring of cerebral perfusion during clamping is an important technical detail in these operations. KAS is performed through a percutaneous transfemoral approach under local anesthesia when a stent is implanted in the carotid artery at the site of the carotid stenosis. To perform this procedure, adequate access is required in terms of the quality of the femoral and iliac blood vessels, i.e. the aortic arch. KAS was introduced into practice much later, and in the last 20 years, there has been a significant improvement both in terms of performance and technology with the development of modern stents and the materials used in their installation. A special contribution to this technique was the introduction of embolization protection. KAS is a complementary method to CEA and an individual approach to the patient enables the choice of method, taking into account the advantages and disadvantages of one and the other method. When it comes to symptomatic patients, CEA certainly has a significantly greater advantage and when the use of CAS should be avoided. Complications of both methods are general, local and neurological, with the latter being the most important. Current recommendations state that performing these procedures is beneficial for the patient if the risk of neurological complications is less than 3% in asymptomatic patients, or less than 6% in symptomatic patients. At the Clinic for Vascular and Univascular Surgery of the Clinical Center of Serbia, in the last fifteen years, almost 9.000 procedures have been performed due to carotid stenosis, of which about 10% (960) were CAS. We opt for this method in patients who are at cardiorespiratory risk for CEA or in whom access to the carotid bifurcation is difficult. All, the CEA procedures are performed under conditions of the cervical block. The improvement of patient stratification and the use of artificial intelligence should in the future help doctors decide on the method of examination and treatment of these patients.

Short-term results of off-pump and on-pump aortic arch debranching during type I hybrid arch repair: A single-center experience

BackgroundCompared with off-pump surgeries, cardiopulmonary bypass (CPB) is associated with a high systemic inflammatory response and with substantial myocardial injury, especially in high-risk subgroups. Every effort should be exerted to minimize the role of CPB without affecting the safety and outcome. Classically, aortic arch surgeries were done using CPB and deep circulatory arrest together with cerebral brain protection strategies. With the development of endovascular techniques, the role of CPB decreased. Management of aortic arch pathologies carries special needs, specifically rerouting of the great vessels and preparing a landing zone.ObjectivesTo assess the effectiveness and safety of off-pump aortic arch debranching during type I hybrid aortic arch repair.Patients and methodsWe report our single-center experience of rerouting aortic arch branches (debranching) without using CPB, consisting of bypass grafting of the aortic arch branches off pump, preparing a landing zone for endovascular aortic repair. The preoperative, operative, and postoperative data were collected and analyzed retrospectively. Starting from 2015, 20 low-risk patients were subjected to type I aortic arch hybrid repair, whereas the Dacron tube graft was anastomosed to a normal ascending aorta, preparing a landing zone to the subsequent stenting of arch and descending aorta. CPB was used in 10 patients, and off-pump technique was used in the remaining group. Preoperative, operative, and postoperative data were collected and analyzed to compare the results.ResultsAll surgeries went uneventful, with mean operative time of 141.5 ± 24.3 min for group I (on-pump group) and 137.5 ± 14.6 for group II (off-pump group). There were no conversions to CPB in off-pump group. There was no sternotomy for bleeding in off-pump group, compared with only one patient explored for postoperative bleeding in CPB group. All patients in both groups went without any neurological deficit of significance, with no mortality in the 30 days of follow-up.ConclusionOff-pump debranching of aortic arch followed by endovascular repair is a safe and reproducible technique, compared with the gold standard technique using CPB. However, further efforts using intraoperative cerebral perfusion monitoring techniques should be considered in the future.

Optimization of time domain diffuse correlation spectroscopy parameters for measuring brain blood flow.

.Significance: Time domain diffuse correlation spectroscopy (TD-DCS) can offer increased sensitivity to cerebral hemodynamics and reduced contamination from extracerebral layers by differentiating photons based on their travel time in tissue. We have developed rigorous simulation and evaluation procedures to determine the optimal time gate parameters for monitoring cerebral perfusion considering instrumentation characteristics and realistic measurement noise.Aim: We simulate TD-DCS cerebral perfusion monitoring performance for different instrument response functions (IRFs) in the presence of realistic experimental noise and evaluate metrics of sensitivity to brain blood flow, signal-to-noise ratio (SNR), and ability to reject the influence of extracerebral blood flow across a variety of time gates to determine optimal operating parameters.Approach: Light propagation was modeled on an MRI-derived human head geometry using Monte Carlo simulations for 765- and 1064-nm excitation wavelengths. We use a virtual probe with a source–detector separation of 1 cm placed in the pre-frontal region. Performance metrics described above were evaluated to determine optimal time gate(s) for different IRFs. Validation of simulation noise estimates was done with experiments conducted on an intralipid-based liquid phantom.Results: We find that TD-DCS performance strongly depends on the system IRF. Among Gaussian pulse shapes, pulse length appears to offer the best performance, at wide gates (500 ps and larger) with start times 400 and 600 ps after the peak of the TPSF at 765 and 1064 nm, respectively, for a 1-s integration time at photon detection rates seen experimentally (600 kcps at 765 nm and 4 Mcps at 1064 nm).Conclusions: Our work shows that optimal time gates satisfy competing requirements for sufficient sensitivity and sufficient SNR. The achievable performance is further impacted by system IRF with quasi-Gaussian pulse obtained using electro-optic laser shaping providing the best results.

The effect of normotensive arterial pressure on cerebral saturation during carotid endarterectomy

Aim: Monitoring of cerebral perfusion during carotid endarterectomy helps to institute early intervention to prevent risk of ischemia during the operation.&#x0D; We aimed to evaluate if the disadvantages of high systemic pressure can be avoided by keeping arterial blood pressure below 150mmHg during cross-clamping of the internal carotid artery by correlating our findings of NIRS values with clinical results&#x0D; Material and Method: This was designed as a prospective study that included elective patients scheduled for an operation of carotid artery stenosis under general anesthesia. A total of 60 patients operated on between August and October 2019 were included in the study. &#x0D; Results: Patients' NIRS findings on the right and left hemispheres were analyzed separately to be able to differentiate any possible changes of NIRS of the cerebral hemisphere ipsilateral to the clamped carotid artery. The analysis of the right and left NIRS findings in these 60 patients revealed a significant decrease between intubation and incision NIRS values (p=0.008 and p= 0.02respectively). &#x0D; Conclusion: Considering the NIRS findings and clinical observations of the patients in the postoperative period, we think that ICA endarterectomy operations may be safe to perform in a suitable patient group while the systolic arterial blood pressure is maintained below 150mmHg during cross-clamping.

Toward Real-time Dye-free Noninvasive Intra-operative Monitoring of Cerebral Perfusion

Toward Real-time Dye-free Noninvasive Intra-operative Monitoring of Cerebral Perfusion

Optical monitoring of cerebral perfusion and metabolism in adults during cardiac surgery with cardiopulmonary bypass.

During cardiac surgery with cardiopulmonary bypass (CPB), adequate maintenance of cerebral blood flow (CBF) is vital in preventing postoperative neurological injury - i.e. stroke, delirium, cognitive impairment. Reductions in CBF large enough to impact cerebral energy metabolism can lead to tissue damage and subsequent brain injury. Current methods for neuromonitoring during surgery are limited. This study presents the clinical translation of a hybrid optical neuromonitor for continuous intraoperative monitoring of cerebral perfusion and metabolism in ten patients undergoing non-emergent cardiac surgery with non-pulsatile CPB. The optical system combines broadband near-infrared spectroscopy (B-NIRS) to measure changes in the oxidation state of cytochrome c oxidase (oxCCO) - a direct marker of cellular energy metabolism - and diffuse correlation spectroscopy (DCS) to provide an index of cerebral blood flow (CBFi). As the heart was arrested and the CPB-pump started, increases in CBFi (88.5 ± 125.7%) and significant decreases in oxCCO (-0.5 ± 0.2 µM) were observed; no changes were noted during transitions off CPB. Fifteen hypoperfusion events, defined as large and sustained reductions in CPB-pump flow rate, were identified across all patients and resulted in significant decreases in perfusion and metabolism when mean arterial pressure dropped to 30 mmHg or below. The maximum reduction in cerebral blood flow preceded the corresponding metabolic reduction by 18.2 ± 15.0 s. Optical neuromonitoring provides a safe and non-invasive approach for assessing intraoperative perfusion and metabolism and has potential in guiding patient management to prevent adverse clinical outcomes.