Carotid Blood Flow Research Articles

Milvexian, an orally bioavailable, small‐molecule, reversible, direct inhibitor of factor XIa: In vitro studies and in vivo evaluation in experimental thrombosis in rabbits

BackgroundMilvexian (BMS‐986177/JNJ‐70033093) is an orally bioavailable factor XIa (FXIa) inhibitor currently in phase 2 clinical trials. ObjectivesTo evaluate in vitro properties and in vivo characteristics of milvexian. MethodsIn vitro properties of milvexian were evaluated with coagulation and enzyme assays, and in vivo profiles were characterized with rabbit models of electrolytic‐induced carotid arterial thrombosis and cuticle bleeding time (BT). ResultsMilvexian is an active‐site, reversible inhibitor of human and rabbit FXIa (Ki 0.11 and 0.38 nM, respectively). Milvexian increased activated partial thromboplastin time (APTT) without changing prothrombin time and potently prolonged plasma APTT in humans and rabbits. Milvexian did not alter platelet aggregation to ADP, arachidonic acid, or collagen. Milvexian was evaluated for in vivo prevention and treatment of thrombosis. For prevention, milvexian 0.063 + 0.04, 0.25 + 0.17, and 1 + 0.67 mg/kg+mg/kg/h preserved 32 ± 6*, 54 ± 10*, and 76 ± 5%* of carotid blood flow (CBF) and reduced thrombus weight by 15 ± 10*, 45 ± 2*, and 70 ± 4%*, respectively (*p < .05; n = 6/dose). For treatment, thrombosis was initiated for 15 min and CBF decreased to 40% of control. Seventy‐five minutes after milvexian administration, CBF averaged 1 ± 0.3, 39 ± 10, and 66 ± 2%* in groups treated with vehicle and milvexian 0.25 + 0.17 and 1 + 0.67 mg/kg+mg/kg/h, respectively (*p < .05 vs. vehicle; n = 6/group). The combination of milvexian 1 + 0.67 mg/kg+mg/kg/h and aspirin 4 mg/kg/h intravenous did not increase BT versus aspirin monotherapy. ConclusionsMilvexian is an effective antithrombotic agent with limited impact on hemostasis, even when combined with aspirin in rabbits. This study supports inhibition of FXIa with milvexian as a promising antithrombotic therapy with a wide therapeutic window.

Validity of transcranial Doppler ultrasonography-determined dynamic cerebral autoregulation estimated using transfer function analysis.

Transcranial Doppler ultrasonography (TCD) is used widely to evaluate dynamic cerebral autoregulation (dCA). However, the validity of TCD-determined dCA remains unknown because TCD is only capable of measuring blood velocity and thus only provides an index as opposed to true blood flow. To test the validity of TCD-determined dCA, in nine healthy subjects, dCA was evaluated by transfer function analysis (TFA) using cerebral blood flow (CBF) or TCD-measured cerebral blood velocity during a perturbation that induces reductions in TCD-determined dCA, lower body negative pressure (LBNP) at two different stages: LBNP - 15mmHg and - 50mmHg. Internal carotid artery blood flow (ICA Q) was assessed as an index of CBF using duplex Doppler ultrasound. The TFA low frequency (LF) normalized gain (ngain) calculated using ICA Q increased during LBNP at - 50mmHg (LBNP50) from rest (P = 0.005) and LBNP at - 15mmHg (LBNP15) (P = 0.015), indicating an impaired dCA. These responses were the same as those obtained using TCD-measured cerebral blood velocity (from rest and LBNP15; P = 0.001 and P = 0.015). In addition, the ICA Q-determined TFA LF ngain from rest to LBNP50 was significantly correlated with TCD-determined TFA LF ngain (r = 0.460, P = 0.016) despite a low intraclass correlation coefficient. Moreover, in the Bland-Altman analysis, the difference in the TFA LF ngains determined by blood flow and velocity was within the margin of error, indicating that the two measurement methods can be interpreted as equivalent. These findings suggest that TCD-determined dCA can be representative of actual dCA evaluated with CBF.

Carotid Artery Ultrasound in the (peri-) Arrest Setting-A Prospective Pilot Study.

Point-of-care ultrasounds (US) are used during cardiopulmonary resuscitation (CPR) and after return of spontaneous circulation (ROSC). Carotid ultrasounds are a potential non-invasive monitoring tool for chest compressions, but their general value and feasibility during CPR are not fully determined. In this prospective observational study, we performed carotid US during conventional- and extracorporeal CPR and after ROSC with at least one transverse and coronal image, corresponding loops with and without color doppler, and pulsed-wave doppler loops. The feasibility of carotid US during (peri-)arrest and type and frequency of diagnostic findings were examined. We recruited 16 patients and recorded utilizable US images in 14 cases (88%; complete imaging protocols in 11 patients [69%]). In three of all patients (19%) and in 60% (3/5) of cases during CPR plus a full imaging protocol, we observed: (i) in one patient a collapse of the common carotid artery linked to hypovolemia, and (ii) in two patients a biphasic flow during CPR linked to prolonged low-flow time prior to admission and adverse outcome. Carotid artery morphology and carotid blood flow characteristics may serve as therapeutic target and prognostic parameters. However, future studies with larger sample sizes are needed.

A comparative analysis of sonographic carotid artery Doppler indices in type 2 diabetics and non-diabetics

Background and Aim: Diabetes mellitus type 2 is a chronic metabolic disorder of global concern with signs of hyperglycemia due to insulin resistance, relative lack of insulin, or both. Stroke is a possible complication of this metabolic disorder as a result of advanced carotid artery atherosclerosis, which diabetic patients develop with attendant carotid blood flow changes. The present study evaluated sonographic carotid artery blood flow velocities in individuals with type 2 diabetics and compared with values in normoglycemic controls. Materials and Methods: This was a prospective case–control study, in which we evaluated carotid Doppler indices in 125 consenting confirmed type 2 diabetics (cases) and 125 age- and gender-matched normoglycemic healthy controls for a period of 6 months (October 2019 to March 2020). The diabetics (cases) were recruited using systematic sampling method and the controls via convenience sampling. Demographic data and anthropometric measurements as well as ultrasound findings were entered into a Microsoft Office Excel Database and analyzed using International Business Machines (IBM) Statistical Package for Social Sciences (SPSS) Version 21. Tables, scatter-plot graphs, and bar charts were used in showing and evaluating the findings. Pearson’s correlation coefficient was used to assess correlation between two continuous variables. Results: The mean age of type 2 diabetics was 67.06±9.8 years, whereas that of the non-diabetics was 66.98±10.7. Females were in majority in both groups (64 in diabetics and 70 in non-diabetics). There were 61 males in the diabetics and 55 males in the non-diabetics. The mean carotid blood flow velocities in the diabetics and non-diabetics were, respectively, as follows: common carotid artery (CCA) end-diastolic velocity (EDV) 21.03±2.3 and 25.22±2.5, CCA peak systolic velocity (PSV) 81.70±4.1 and 83.60±3.6, internal carotid artery (ICA) EDV 17.99±5.6 and 21.57±2.0, ICA PSV 69.30±5.1 and 73.87±2.1, and ICA/CCA PSV ratio 0.83±01 and 0.91±0.1. Conclusion: Type 2 diabetics had significantly lower carotid blood flow velocities than non-diabetics. This suggests that proper management and compliance with care may reduce the development of features of atherosclerosis in type 2 diabetics.

Carotid Artery Blood Flow Changes Associated with Head Positioning in Patients Undergoing Thyroidectomy.

Background and Aims:There are possibilities of insufficiency in blood flow through carotid arteries during head positioning in thyroid surgeries under general anesthesia which is usually compensated by collateral circulation in normal conditions. This compensation may be hampered in patients with congenital abnormalities or diseases such as atherosclerosis. We aimed to elucidate the changes in common carotid artery blood flow related to head positioning during thyroid surgery by Doppler examination.Methods:In this observational prospective study, Doppler examination of both common carotid arteries including arterial diameter, peak systolic velocity, average velocity, and blood flow volume of forty patients who had undergone elective thyroidectomy under endotracheal anesthesia was done. Three sets of data (baseline, after induction, and after surgery) were collected and analyzed.Results:There was a significant reduction in the diameter (P = 0.002) and the blood flow (P = 0.0001) in both carotid arteries and an increase in peak and mean velocity which was more pronounced immediately after head positioning and persisted till the end of the procedure. There was no correlation between the hemodynamic parameters with the carotid artery diameter, blood flow, and velocity.Conclusions:The head-and-neck positioning during thyroidectomy surgery reduces the blood flow through the carotid arteries which continued till the end of the procedure.

Sonographic Assessment of the Effects of Mechanical Ventilation on Carotid Flow Time and Volume.

BackgroundCorrected carotid flow time (CFTc) and carotid blood flow (CBF) are sonographic measurements used to assess fluid responsiveness in hypotension. We investigated the impacts of mechanical ventilation on CFTc and CBF.Materials and methodsNormotensive patients undergoing cardiac surgery were prospectively enrolled. Carotid ultrasound (US) was performed pre and post-intubation. Post-intubation measurements took place after the initiation of mechanical ventilation. To measure CFTc and CBF, a sagittal carotid view was obtained with pulse wave-Doppler (maximum angle 60°). CFTc was calculated with the Bazett formula (CFTc = systolic time/√cycle time). CBF was calculated using CBF (mL/min) = area (cm 2 ) x time average mean velocity (TAMEAN) (cm/sec) x 60 (sec/min). The maximum carotid diameter was measured at the level of the thyroid.ResultsTwenty patients were enrolled. Mean CFTc pre-intubation was 328 ms (SD 43.9 ms) compared to CFTc post-intubation 336 ms (SD 36 ms). There was no significant difference between pre and post-intubation CFTc (mean differences=-0.008; t(19)=-0.71, p=.49). Mean CBF pre-intubation was 487 mL/min (SD 176 mL/min) compared to CBF post-intubation 447 mL/min (SD 187 mL/min). There was no significant difference between pre and post-intubation CBF (mean differences= 40; t(19)=1.24, p=.23).ConclusionsIn this study of normotensive patients, there were no detected differences in CFTc or CBF pre and post-intubation with mechanical ventilation.

Perfusion of Brain Preautonomic Areas in Hypertension: Compensatory Absence of Capillary Rarefaction and Protective Effects of Exercise Training.

Remodeling of capillary rarefaction and deleterious arteries are characteristic hallmarks of hypertension that are partially corrected by exercise training. In addition, experimental evidence showed capillary rarefaction within the brain cortex and reduced cerebral blood flow. There is no information on hypertension- and exercise-induced effects on capillary profile and function within preautonomic nuclei. We sought now to evaluate the effects of hypertension and exercise training (T) on the capillary network within hypothalamic paraventricular (PVN) and solitary tract (NTS) nuclei, and on the remodeling of brain arteries. Age-matched spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY), submitted to moderate T or kept sedentary (S) for three months, were chronically cannulated for hemodynamic recordings at rest. Rats were anesthetized for i.v. administration of fluorescein isothiocyanate (FITC)-dextran (capillary volume/density measurements) or 4% paraformaldehyde perfusion (basilar, middle, and posterior arteries' morphometry) followed by brain harvesting and processing. Other groups of conscious rats had carotid blood flow (CBF, ultrasound flowmeter) acquired simultaneously with hemodynamic recordings at rest and exercise. SHR-S exhibited elevated pressure and heart rate, reduced CBF, increased wall/lumen ratio of arteries, but no capillary rarefaction within the PVN and NTS. T improved performance gain and caused resting bradycardia in both groups; reduction of pressure and sympathetic vasomotor activity and normalization of the wall/lumen ratio were only observed in SHR-T. T groups responded with marked PVN and NTS capillary angiogenesis and augmented CBF during exercise; to avoid overperfusion at rest, reduced basal CBF was observed only in WKY-T. Data indicated that the absence of SHR-S capillary rarefaction and the intense SHR-T angiogenesis within autonomic areas associated with correction of deleterious arteries' remodeling are essential adjustments to hypertension and exercise training, respectively. These adaptive responses maintain adequate baseline perfusion in SHR-S and SHR-T preautonomic nuclei, augmenting it in exercised rats when a well-coordinated autonomic control is required.

Oncologic surgical resection with intravascular covered stent placement in patients with carotid artery encased by metastatic cancer-Our experience with 5 patients.

Importance Tumor encasement of the common carotid artery (CCA) and/or the internal carotid artery (ICA) in patients with advanced head and neck tumors represents a significant surgical challenge. At present, there are few reports on the treatment approach that can achieve the maximal oncological resection and reduce the difficulty of operation without affecting the carotid artery blood flow. Objective To examine whether the combination of oncologic complete tumor resection and intravascular covered stent placement is more advantageous in the management of advanced head and neck cancer. Design, setting, and participants Five patients with advanced head and neck squamous cell carcinoma (AHNSCC) invading one side of the carotid artery were retrospectively enrolled. The contrast-enhanced computed Tomography (CT) and angiography were performed to assess the severity of extrinsic tumor compression to the carotid artery. Covered stent was placed intra-arterially at least 1 cm proximal and distal beyond the area of tumor involvement. The tumor and the involved carotid artery were resected, and pectoralis major flap transfer was utilized for coverage of the great vessels supported with intra-arterial covered stent. Main outcomes and measures Efficacy of oncologic complete tumor resection combined with endovascular stent placement. Results The post-stenting demonstrated an improvement in the appearance and caliber of the affected carotid artery. Four patients experienced transient bradycardia and hypotension. All five patients underwent R0 resection. Postoperatively, the flap all had rich vascularity and healing. Three patients underwent adjuvant radiotherapy or chemoradiation. With median follow-up 6.5 months, one patient died of multiple organ failures at 6.5 months after surgery; one patient developed tracheal stoma recurrence and treated with salvaged surgery; the three other patients had no disease recurrence in their last follow-ups. Conclusions and relevance Surgical resection with intravascular covered stent placement could potentially achieve the maximal oncological resection without compromise carotid artery blood flow in patients with carotid artery encased head and neck cancer.

Abstract 9934: High Mean Arterial Pressure Aggravates Cerebral Hemodynamics After Extracorporeal Resuscitation in Swine

Introduction: Extracorporeal cardiopulmonary resuscitation (E-CPR) is used for the treatment of refractory cardiac arrest but the optimal target to reach for mean arterial pressure (MAP) remains to be determined. Hypothesis: We hypothesized that MAP levels modify cerebral hemodynamics during E-CPR. Accordingly, we tested two MAP targets (65-75 vs 80-90 mmHg) in a porcine model of E-CPR. Methods: Pigs were anesthetized and instrumented for the evaluation of cerebral and systemic hemodynamics. They were submitted to 15 min of untreated ventricular fibrillation followed by 30 min of E-CPR. Electric attempts of defibrillation were then delivered until resumption of spontaneous circulation (ROSC). Extracorporeal circulation was initially set to an average flow of 40 ml/kg/min with a standardized volume expansion in both groups. The dose of epinephrine was set to reach either a standard or a high MAP target level (65-75 vs 80-90 mmHg, respectively). Animals were followed during 120 min after ROSC. Results: Six animals were included in both groups. After cardiac arrest, MAP was maintained at the expected level (Figure). During E-CPR, high MAP transiently improved carotid blood flow as compared to standard MAP. This blood flow progressively decreased after ROSC in high vs standard MAP, while intra-cranial pressure increased. Interestingly, this was associated with a significant decrease in cerebral oxygen consumption (26±8 vs 54±6 L O 2 /min/kg at 120 min after ROSC, respectively; p&lt;0.01) (Figure). The pressure reactivity index (PRx), which is the correlation coefficient between arterial blood pressure and intracranial pressure, became positive in high MAP (0.47±0.02) vs standard MAP group (-0.16±0.10), demonstrating altered cerebral autoregulation with high MAP. Conclusion: Increasing MAP above 80 mmHg with epinephrine aggravates cerebral hemodynamics after E-CPR. Figure: Mean arterial pressure (MAP), cerebral blood flow and oxygen consumption (*, p&lt;0.05)

Targeted high mean arterial pressure aggravates cerebral hemodynamics after extracorporeal resuscitation in swine

BackgroundExtracorporeal cardiopulmonary resuscitation (E-CPR) is used for the treatment of refractory cardiac arrest. However, the optimal target to reach for mean arterial pressure (MAP) remains to be determined. We hypothesized that MAP levels critically modify cerebral hemodynamics during E-CPR and tested two distinct targets (65–75 vs 80–90 mmHg) in a porcine model.MethodsPigs were submitted to 15 min of untreated ventricular fibrillation followed by 30 min of E-CPR. Defibrillations were then delivered until return of spontaneous circulation (ROSC). Extracorporeal circulation was initially set to an average flow of 40 ml/kg/min. The dose of epinephrine was set to reach a standard or a high MAP target level (65–75 vs 80–90 mmHg, respectively). Animals were followed during 120-min after ROSC.ResultsSix animals were included in both groups. During E-CPR, high MAP improved carotid blood flow as compared to standard MAP. After ROSC, this was conversely decreased in high versus standard MAP, while intra-cranial pressure was superior. The pressure reactivity index (PRx), which is the correlation coefficient between arterial blood pressure and intracranial pressure, also demonstrated inverted patterns of alteration according to MAP levels during E-CPR and after ROSC. In standard-MAP, PRx was transiently positive during E-CPR before returning to negative values after ROSC, demonstrating a reversible alteration of cerebral autoregulation during E-CPR. In high-MAP, PRx was negative during E-CPR but became sustainably positive after ROSC, demonstrating a prolonged alteration in cerebral autoregulation after ROSC. It was associated with a significant decrease in cerebral oxygen consumption in high- versus standard-MAP after ROSC.ConclusionsDuring early E-CPR, MAP target above 80 mmHg is associated with higher carotid blood flow and improved cerebral autoregulation. This pattern is inverted after ROSC with a better hemodynamic status with standard versus high-MAP.

Automated pupillometry helps monitor the efficacy of cardiopulmonary resuscitation and predict return of spontaneous circulation.

We investigated the effectiveness of automated pupillometry on monitoring cardiopulmonary resuscitation (CPR) and predicting return of spontaneous circulation (ROSC) in a swine model of cardiac arrest (CA). Sixteen male domestic pigs were included. Traditional indices including coronary perfusion pressure (CPP), end-tidal carbon dioxide (ETCO2), regional cerebral tissue oxygen saturation (rSO2) and carotid blood flow (CBF) were continuously monitored throughout the experiment. In addition, the pupillary parameters including the initial pupil size before constriction (Init, maximum diameter), the end pupil size at peak constriction (End, minimum diameter), and percentage of change (%PLR) were measured by an automated quantitative pupillometer at baseline, at 1, 4, 7 min during CA, and at 1, 4, 7 min during CPR. ROSC was achieved in 11/16 animals. The levels of CPP, ETCO2, rSO2 and CBF were significantly greater during CPR in resuscitated animals than those non-resuscitated ones. Init and End were decreased and %PLR was increased during CPR in resuscitated animals when compared with those non-resuscitated ones. There were moderate to good significant correlations between traditional indices and Init, End, and %PLR (|r| = 0.46-0.78, all P < 0.001). Furthermore, comparable performance was also achieved by automated pupillometry (AUCs of Init, End and %PLR were 0.821, 0.873 and 0.821, respectively, all P < 0.05) compared with the traditional indices (AUCs = 0.809-0.946). The automated pupillometry may serve as an effective surrogate method to monitor cardiopulmonary resuscitation efficacy and predict ROSC in a swine model of cardiac arrest.

Hemodynamic Effect of Resuscitative Endovascular Balloon Occlusion of the Aorta in Hemodynamic Instability Secondary to Acute Cardiac Tamponade in a Porcine Model.

The pre-hospital use of Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is increasing, although it remains controversial, in part because of suggested contraindications such as acute cardiac tamponade (ACT). As both the pre-hospital and in-hospital use of REBOA might potentially occur with concurrent ACT, knowledge of the hemodynamic effect of REBOA in this setting is crucial. This study, therefore, aimed at investigating the physiological effects of REBOA in hemodynamic instability secondary to ACT in a porcine model. We hypothesize that REBOA can temporarily increase systemic blood pressure and carotid blood flow, and prolong survival, in hemodynamic shock caused by ACT. Fourteen pigs (24-38 kg) underwent ACT, through true cardiac injury and hemorrhage into the pericardial space, and were allowed to hemodynamically deteriorate. At a systolic blood pressure (SBP) of 50 mm Hg (SBP50) they were randomized to total occlusion REBOA in zone 1 or to a control group. Survival, hemodynamic parameters, carotid blood flow (CBF), femoral blood flow (FBF), cardiac output (CO), end-tidal CO2, and arterial blood gas parameters were analyzed. REBOA intervention was associated with a significant increase in SBP (50 mm Hg to 74 mm Hg, P = 0.016) and CBF (110 mL/min to 195 mL/min, P = 0.031), with no change in CO, compared to the control group. At 20 min after SBP50, the survival rate in the intervention group was 86% and in the control group 14%, with time to death being significantly longer in the intervention group. This randomized animal study demonstrates that REBOA can help provide hemodynamic stabilization and prolong survival in hemodynamic shock provoked by ACT. It is important to stress that our study does not change the fact that urgent pericardiocentesis or cardiac surgery is, and should remain, the standard optimal treatment for ACT.Level of evidence: Prospective, randomized, experimental animal study. Basic science study, therapeutic.

Correlation of Carotid Doppler Blood Flow With Invasive Cardiac Output Measurements in Cardiac Surgery Patients

Carotid Doppler ultrasound has been a topic of recent interest, as it may be a promising noninvasive hemodynamic monitoring tool. In this study, the relation between carotid artery blood flow and invasive cardiac output (CO) was evaluated. A prospective, observational study. A single-institution, tertiary referral hospital. Eighteen elective cardiac surgery patients. CO was measured by calibrated pulse contour analysis. Simultaneously, carotid artery pulsed-wave Doppler measurements were obtained in the operating room in three clinical settings: after induction of anesthesia (T1), after a passive leg raise maneuverer (T2), and at the end of surgery (T3). Correlation and trending between carotid artery blood flow and invasive CO were evaluated. Furthermore, two Bland-Altman plots were constructed to evaluate the level of agreement between carotid artery-derived CO and invasive CO measurements. Carotid artery blood flow correlated moderately with invasive CO (ρ=0.67, 95% confidence interval 0.56-0.76, p < 0.05). Concordance between the percentage change of carotid artery blood flow and invasive CO from T1 to T3 was 72%. The level of agreement between carotid artery-derived CO and invasive CO was ±2.29; ±2.57 L/min, with a bias of 0.1; -0.54 L/min, and mean error of 50% and 48%, for the two Bland-Altman analyses, respectively. Intraexamination precision was acceptable. In cardiac surgery patients, carotid artery blood flow correlated moderately with invasive CO measurements. However, the trending ability of carotid artery blood flow was poor, and carotid artery-derived CO tended not to be interchangeable with invasive CO.

Compression depth of 30 mm has similar efficacy and fewer complications versus 50 mm during mechanical chest compression with miniaturized chest compressor in a porcine model of cardiac arrest.

BackgroundCurrent guidelines recommend a 50 mm or greater compression depth for manual chest compression in adults. However, whether this uniform compression depth is a suitable requirement for mechanical CPR remains to be determined. We hypothesized that a relatively shallow compression depth (30 mm) would have similar hemodynamic efficacy but fewer complications versus the standard compression depth (50 mm) during mechanical cardiopulmonary resuscitation (CPR) with the miniaturized chest compressor (MCC) in a porcine model.MethodsIn the current study, we used a total of 16 domestic male pigs (38±2 kg). All pigs were exposed to 7 min of ventricular fibrillation (VF) followed by 5 min of CPR. Then the animals were randomly assigned to the shallow (30 mm) group and the standard (50 mm) group. At the second min of CPR, every pig was given epinephrine (20 µg/kg) through the femoral vein and repeated every 3 min. First defibrillation was delivered with a single 120 J shock at 5 min of CPR. Hemodynamics, carotid blood flow (CBF), end-tidal carbon dioxide (ETCO2), coronary perfusion pressure (CPP), intrathoracic pressure (ITP) and arterial blood gas were measured. Rib fractures and lung injuries, as indicated by ground-glass opacification (GGO), as well as intense parenchymal opacification (IPO), were assessed and calculated by quantitative computed tomography (QCT) scan.ResultsWe found no significant differences in CPP, CBF, or ETCO2 between the both groups throughout the CPR period. After administration of epinephrine, the CPP of all animals increased while ETCO2 and CBF decreased during CPR. A significantly lower intrathoracic positive pressure (ITPP) and systolic artery pressure (SAP) were measured in the shallow group at the first min of CPR. However, we didn’t find remarkable differences in these values between the both groups for the next 4 min of CPR. All animals were successfully resuscitated. The shallow group had significantly lower IPO QCT scores compared with the standard group. We found no significant differences in GGO QCT scores after resuscitation between both groups.ConclusionsRelatively shallow compression depth has similar hemodynamic efficacy but fewer complications versus the standard compression depth.

Carotid Sound Signal Artifact Detection based on Discrete Wavelet Transform Decomposition

Abstract Auscultation methods allow a non-invasive diagnosis of cardiovascular diseases like atherosclerosis based on blood flow sounds of the carotid arteries. Since this process is highly dependent on the clinician’s experience, it is of great interest to develop automated data processing techniques for objective assessment. We have recently proposed a computerassisted auscultation system that we use to acquire carotid blood flow sounds. In this work, we present an approach for detecting artifacts within the blood flow sound caused by swallowing or coughing events. For this purpose, we first decompose the signal using a discrete wavelet transform (DTW). Then, we compute an energy ratio between the DWT scales associated with the signal information with and without artifacts using a sliding window of 1 s length. Evaluation based on Kruskal-Wallis and Wilcoxon rank-sum tests shows a statistically significant difference (p-value&lt;.0001) between the signal with and without artifact. Therefore, the proposed method allows the identification of the studied signal artifacts.

Postoperative Stroke after Anterior Cervical Discectomy and Fusion: A Clinical Case Report

Anterior cervical discectomy and fusion (ACDF) spine surgery has been performed extensively for the treatment of degenerative spine diseases with relatively low rates of complications. The reported incidence of postoperative cerebrovascular events associated with ACDF is only 0.13%, representing 1.51% of all complications. However, this complication is often highly disastrous and can lead to paralysis, and even death. In this study, a 42year-old male underwent anterior cervical discectomy and fusion (ACDF) at C34 and C45 levels through a right-sided approach. Three hours after the surgery, the patient suddenly developed left hemiplegia and facial palsy.. The patient was treated with aspirin and cerebromysin and fully recovered from motor and sensory deficits after 1 month.&#x0D; Keywords: Anterior cervical discectomy and fusion, postoperative stroke.&#x0D; References&#x0D; [1] P. S. Romano, D. R. Campa, J. A. Rainwater, Elective Cervical Discectomy in California: Postoperative in Hospital Complications And Their Risk Factors, Spine, Vol. 22, No. 1, 1997, pp. 2677-2692, https://doi.org/10.1097/00007632-199711150-00018.[2] B. S. Chozick, P. Watson, S. H. Greenblatt, Internal Carotid Artery Thrombosis After Cervical Corpectomy, Spine, Vol. 19, 1994, pp. 2230-2232, https://doi.org/10.1097/00007632-199410000-00020.[3] Y. C. Yeh, W. Z. Sun, C. P. Lin et al., Prolonged Retraction on The Normal Common Carotid Artery Induced Lethal Stroke After Cervical Spine Surgery, Spine, Vol. 29, No. 3, 2004, pp. 431-434, https://doi.org/10.1097/01.brs.0000141177.95850.b1.[4] J. E. Loret, P. Francois, C. Papagiannaki, Internal Sarotid Artery Dissection After Anterior Cervical Disc Replacement: First Case Report And Literature Review of Vascular Complications of The Approach, Eur J Orthop Surg Traumatol, Vol. 23, No. 1, 2013, pp. 107-110, https://doi.org/10.1007/s00590-013-1228-8.[5] M. Radhakrishnan, S. Bansal, G. S. Srihari, Perioperative Stroke Following Anterior Cervical Discectomy, Br J Neurosurg, Vol. 24, No. 1, 2010, pp. 592-594, https://doi.org/10.3109/02688691003711575.[6] Q. D. Yue, Carotid Artery Related Perioperative Stroke Following Anterior Cervical Spine Surgery: A Series of 3 Cases and Literature Review, Journal of Stroke And Cerebrovascular Diseases, Vol. 28, No. 2, 2019, pp. 458-463, https://doi.org/10.1016/j.jstrokecerebrovasdis.2018.10.024.[7] E. Matthew, Changes in Carotid Artery Blood Flow During Anterior Cervical Spine Surgery, Spine, Vol. 27, No. 2, 2002, pp. 152-155, https://doi.org/10.1177/2192568216688192.[8] D. C. Brooks, J. L. Schindler, Perioperative Stroke: Risk Assessment, Prevention and Treatment, Curr Treat Options Cardiovasc, Meds, Vol. 16, No. 1, 2014, pp. 282, https://doi.org/10.1007/s11936-013-0282-1.[9] E. C. Jauch, J. L. Saver, J. Adams, Guidelines for The Early Management of Patients with Acute Ischemic Stroke: A Guideline for Healthcare Professionals from The American Heart Association, American Stroke Association, Vol. 44, No. 1, 2013, pp. 870-947, https://doi.org/10.1161/STR.0b013e318284056a.[10] J. M. Cuellar, A. Petrizzo, R. Vaswani, Does Aspirin Administration Increase Perioperative Morbidity in Patients With Cardiac Stents Undergoing Spinal Surgery, Spine, Vol. 44, No. 1, 2015, pp. 629-635, https://doi.org/10.1097/BRS.0000000000000695.&#x0D; &#x0D;

Carotid Doppler Ultrasonography for Hemodynamic Assessment in Critically Ill Children.

An accurate assessment of cardiovascular performance is essential to predict and evaluate hemodynamic response to interventions. The objective of this prospective study was to assess whether point-of-care ultrasonography of the common carotid artery (CCA) can estimate the stroke volume (SV) and cardiac index (Ci) of critically ill children. Participants underwent Doppler ultrasonography of the left CCA and transthoracic echocardiography (TTE). Variables measured by TTE were SV and Ci. Carotid blood flow (CBF) was calculated based on both systolic velocity-time integral (CBF(s)) and total velocity-time integral (CBF(t)). Carotid corrected flow time(CFT)was also determined. A total of 50 children were enrolled. The median age and weight of participants were 36.0months and 14.2kg, respectively. Both CBF(s) and CBF(t) correlated very strongly with SV (ρ = 0.98 and 0.97, respectively) and Ci (ρ = 0.96 and 0.92, respectively). Agreement analysis showed low biases and clinically acceptable percentage errors between variables measured by TTE (SV and Ci) and those estimated by Doppler ultrasonography. Linear regression analysis revealed that the Ci of mechanically ventilated children can be estimated by the following equation: [Formula: see text]. CFT did not significantly correlate with SV or Ci (ρ = 0.27 and 0.05, respectively). Doppler ultrasonography of the left CCA is able to estimate the SV and Ci of critically ill children. Therefore, the CDU may be considered as an alternative for estimating Ci in critically ill children when TTE is not feasible or available.

A method to evaluate dynamic cerebral pressure-flow relationships in the conscious rat.

The classic dogma of cerebral autoregulation is that cerebral blood flow is steadily maintained across a wide range of perfusion pressures. This has been challenged by recent studies suggesting little to no "autoregulatory plateau" in the relationship between cerebral blood flow and blood pressure (BP). Therefore, the mechanisms underlying the cerebral pressure-flow relationship still require further understanding. Here, we present a novel approach to examine dynamic cerebral autoregulation in conscious Wistar rats (n = 16) instrumented to measure BP and internal carotid blood flow (iCBF), as an indicator of cerebral blood flow. Transient reductions in BP were induced by occluding the vena cava via inflation of a chronically implanted intravascular silicone balloon. Falls in BP were paralleled by progressive decreases in iCBF, with no evidence of a steady-state plateau. No significant changes in internal carotid vascular resistance (iCVR) were observed. In contrast, intravenous infusions of the vasoactive drug sodium nitroprusside (SNP) produced a similar fall in BP but increases in iCBF and decreases in iCVR were observed. These data suggest a considerable confounding influence of vasodilatory drugs such as SNP on cerebrovascular tone in the rat, making them unsuitable to investigate cerebral autoregulation. We demonstrate that our technique of transient vena cava occlusion produced reliable and repeatable depressor responses, highlighting the potential for our approach to permit assessment of the dynamic cerebral pressure-flow relationship over time in conscious rats.NEW & NOTEWORTHY We present a novel technique to overcome the use of vasoactive agents when studying cerebrovascular dynamics in the conscious rat. Our method of vena cava occlusion to reduce BP was associated with decreased iCBF and no change in iCVR. In contrast, comparable BP falls with intravenous SNP increased iCBF and reduced iCVR. Thus, the dynamic cerebral pressure-flow relationship shows a narrower, less level autoregulatory plateau than conventionally thought. We confirm our method allows repeatable assessment of cerebrovascular dynamics in conscious rats.

Comparison of intraosseous and intravenous epinephrine administration during resuscitation of asphyxiated newborn lambs

ObjectiveIntraosseous access is recommended as a reasonable alternative for vascular access during newborn resuscitation if umbilical access is unavailable, but there are minimal reported data in newborns. We compared intraosseous...

Sex- and Age-Related Physiological Profiles for Brachial, Vertebral, Carotid, and Femoral Arteries Blood Flow Velocity Parameters During Growth and Aging (4–76 Years): Comparison With Clinical Cut-Off Levels

Ultrasound-derived blood flow velocity (BFV) levels [e.g., peak systolic velocity (PSV)], intrabeat indexes (e.g., resistive), and intersegment ratios [e.g., internal/common carotid artery (ICA/CCA) PSV ratio] are assessed to describe cardiovascular physiology and health status (e.g., disease severity evaluation and/or risk stratification). In this respect, fixed cut-off values (disregard of age or sex) have been proposed to define “significant” vascular disease from BFV-derived data (parameters). However, the use of single fixed cut-off values has limitations. Accurate use of BFV-derived parameters requires knowing their physiological age-related profiles and the expected values for a specific subject. To our knowledge, there are no studies that have characterized BFV profiles in large populations taking into account: (i) data from different age-stages (as a continuous) and transitions (childhood–adolescence–adulthood), (ii) complementary parameters, (iii) data from different arteries, and (iv) potential sex- and hemibody-related differences. Furthermore, (v) there is little information regarding normative data [reference intervals (RIs)] for BFV indexes.Aims: The aims of this study are the following: (a) to determine the need for age-, body side-, and sex-specific profiles for BFV levels and derived parameters (intrabeat indexes and intersegment ratios), and (b) to define RIs for BFV levels and parameters, obtained from CCA, ICA, external carotid, vertebral, femoral, and brachial arteries records.Methods: A total of 3,619 subjects (3–90 years) were included; 1,152 were healthy (without cardiovascular disease and atheroma plaques) and non-exposed to cardiovascular risk factors. BFV data were acquired. The agreement between left and right data was analyzed (Concordance correlation, Bland–Altman). Mean and SD equations and age-related profiles were obtained for BFV levels and parameters (regression methods; fractional polynomials).Results: Left and right body-side derived data were not always equivalent. The need for sex-specific RIs was dependent on the parameter and/or age considered. RIs were defined for each studied artery and parameter. Percentile curves were compared with recommended fixed cut-off points. The equations for sex, body-side, and age-specific BFV physiological profiles obtained in the large population (of children, adolescents, and adults) studied were included (spreadsheet formats), enabling to determine for a particular subject, the expected values and potential data deviations.