Artery Blood Flow Velocity Research Articles

Carotid artery blood flow velocities during open-heart surgery and its association with delirium: A prospective, observational pilot study.

The aim of this prospective observational single-centre pilot study was to evaluate the association between alterations in carotid artery blood flow velocities during cardiac surgery and postoperative delirium.Carotid artery blood flow velocity was determined perioperatively at 5 different timepoints by duplex sonography in 36 adult cardiac surgical patients. Delirium was assessed using the Confusion Assessment Method for the ICU and the Intensive Care Delirium Screening Checklist. Additionally, blood flow velocities in the middle cerebral arteries, differences in regional cerebral tissue oxygenation and quantity and quality of microemboli were measured.Delirium was detected in 7 of 36 patients. After cardiopulmonary bypass carotid artery blood flow velocities increased by +23 cm/second (95% confidence interval (CI) 9-36 cm/second) in non-delirious patients compared to preoperative values (P = .002), but not in delirious patients (+3 cm/second [95% CI -25 to 32 cm/second], P = .5781). Middle cerebral artery blood flow velocities were higher at aortic de-cannulation in non-delirious patients (29 cm/second [inter-quartile range (IQR), 24-36 cm/second] vs 12 cm/second [IQR, 10-19 cm/second]; P = .017). Furthermore, brain tissue oxygenation was higher in non-delirious patients during surgery.Our results suggest that higher cerebral blood flow velocities after aortic de-clamping and probably also improved brain oxygenation might be beneficial to prevent postoperative delirium.

Transcranial Doppler Velocities Conversion Rate Based on Increasing Hemoglobin Concentration: Analysies from the SCCRIP Cohort Study

Transcranial Doppler Velocities Conversion Rate Based on Increasing Hemoglobin Concentration: Analysies from the SCCRIP Cohort Study

Middle Cerebral Artery Blood Flow Velocity as an Indicator of Attentional Load and Attentional Resource Depletion in the Laparoscopic Training Environment

Middle Cerebral Artery Blood Flow Velocity as an Indicator of Attentional Load and Attentional Resource Depletion in the Laparoscopic Training Environment

Atherosclerosis and the Structural and Functional State of the Vessels of the Carotid and Vertebro-basilar Basins

In connection with modern pathogenetic ideas about the mechanisms of development of ischemic stroke, the early diagnosis of this disease becomes even more important. A relevant issue at the present stage is the information content of non-invasive ultrasound research methods used to study the state of the cerebral arteries that participate in the blood supply to the brain.The objective: to study the structural and functional state of the vessels of the carotid and vertebro-basilar pools in elderly patients with cerebral atherosclerosis (CA) of stage 1–3, including depending on the hemispheric localization of the ischemic focus.Materials and methods. 229 patients with CA of the 2nd – 3rd degree took part in a comprehensive clinical and instrumental study. Patients were divided into 4 groups: I – the general group of patients who underwent ischemic atherothrombotic stroke in the basin of the middle cerebral artery (IS); II – in the right hemisphere (RH); ІІІ – transferred IS in the left hemisphere (LH); ІV – with CA of 1–2 degree (without IS – comparison group). Subsequently, elderly patients from 55 to 75 years old participated in the comparison of groups.Results. In chronic cerebrovascular diseases, a steadily progressing atherosclerotic process is accompanied by a decrease in blood flow velocity in the main arteries of the head. Moreover, changes in LSBV (Linear systolic blood velocity) are detected by transcranial dopplerography at earlier stages both at the extra– and intracranial level, and blood flow depression initially occurs both in the arteries of the vertebro-basilar basin and in the carotid channel. The identification of changes in a Doppler study, in general, precedes the increase in symptoms of organic damage to the nervous system. Compared to patients with initial manifestations of CA, patients who underwent IS are characterized by a high frequency of hemodynamically significant stenosis, a thickening of complex intima-media, a statistically significant decrease in LSBV and an increase in pulsatory and peripheral resistance index in individual vessels of the carotid and vertebro basilar basins on both sides.Conclusion. Structural and functional features of cerebral vessels in patients after ischemic atherothrombotic stroke in the late recovery period have hemispheric features. Moreover, a statistically significant difference in the rate of cerebral blood flow was observed only in the vessels of the carotid basin on the right, and the indices of peripheral vascular resistance and pulsativity were increased in different vessels of both pools from 2 sides.

Estimation of Blood Flow Velocity in Coronary Arteries Based on the Movement of Radiopaque Agent

Estimation of Blood Flow Velocity in Coronary Arteries Based on the Movement of Radiopaque Agent

The Effect of Stroke on Middle Cerebral Artery Blood Flow Velocity Dynamics During Exercise.

Previous work demonstrates that older adults have a lower response in the middle cerebral artery velocity (MCAv) to an acute bout of moderate-intensity exercise when compared with young adults. However, no information exists regarding MCAv response to exercise after stroke. We tested whether MCAv response to an acute bout of moderate-intensity exercise differed between participants 3 months after stroke and an age- and sex-matched control group of older adults (CON). A secondary objective was to compare MCAv response between the stroke- and non-stroke-affected MCAv. Using transcranial Doppler ultrasound, we recorded MCAv during a 90-second baseline (BL) followed by a 6-minute moderate-intensity exercise bout using a recumbent stepper. Heart rate (HR), end-tidal CO2 (PETCO2), and beat-to-beat mean arterial blood pressure (MAP) were additional variables of interest. The MCAv response measures included BL, peak response amplitude (Amp), time delay (TD), and time constant (τ). The Amp was significantly lower in the stroke-affected MCAv compared with CON (P < 0.01) and in the nonaffected MCAv compared with CON (P = 0.03). No between-group differences were found between TD and τ. No significant differences were found during exercise for PETCO2 and MAP while HR was lower in participants with stroke (P < 0.01). Within the group of participants with stroke, no differences were found between the stroke-affected and non-stroke-affected sides for any measures. Resolution of the dynamic response profile has the potential to increase our understanding of the cerebrovascular control mechanisms and test cerebrovascular response to physical therapy-driven interventions such as exercise.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A284).

Cerebrovascular Pulsatility During Rest and Exercise Reflects Hemodynamic Impairment in Stroke and Cerebral Small Vessel Disease

Although aerobic exercise is recommended as a core component of stroke rehabilitation, knowledge of acute cerebrovascular responses in patients is limited. This study tested the hypothesis that older adults with chronic stroke or cerebral small vessel disease (SVD) exhibit a greater increase in pulsatile hemodynamics during exercise compared with young and age-matched healthy adults. Middle cerebral artery blood flow velocity was acquired during 20 min of moderate intensity cycling in 51 participants from four groups (young, old, SVD and stroke). During rest, only the stroke group had a higher pulsatility index (PI) compared with the young group (1.02 ± 0.17 vs 0.83 ± 0.13; p = 0.038). During exercise, however, the SVD group exhibited a larger increase in PI (68 ± 20% relative to rest) than the young (47 ± 19%), old (45 ± 17%) and stroke (40 ± 25%) groups (p < 0.05, for each). The stress of aerobic exercise may reveal arterial dysfunction associated with latent and overt cerebrovascular disease.

Safety and Clinical Efficacy of Yangxue Qingnao Granules in the Treatment of Chronic Cerebral Circulation Insufficiency: A Systematic Review and Meta-Analysis.

To evaluate the safety and clinical efficacy of Yangxue Qingnao (YXQN) granules in the treatment of chronic cerebral circulation insufficiency (CCCI), electronic databases—PubMed, Embase, CNKI, VIP, and Wangfang—were searched for randomized controlled trials (RCTs) published up to January 2019. GRADE and RevMan 5.3.0 were used for grading and analysis, respectively. Fifteen trials involving 1211 CCCI patients were included. Subgroup analysis was performed owing to study heterogeneity. Compared to nimodipine plus routine treatment, YXQN granules plus routine treatment were more effective in increasing basilar artery (BA) blood flow velocity (mean difference (MD) = 3.34, 95% confidence interval (CI) = [2.31, 4.37], P < 0.00001), vertebral artery (VA) blood flow velocity (MD = 0.52, 95% CI = [0.27, 0.76], P < 0.0001), and internal carotid artery (ICA) blood flow velocity (MD = 7.46, 95% CI = [2.01, 12.90], P=0.007). In improving the clinical efficacy of traditional Chinese medicine (TCM) for symptoms such as headache, dizziness, and insomnia, YXQN granules plus routine treatment were shown to be superior to the following control treatments: nimodipine plus routine treatment (mean difference (M-H) = 4.21, 95% CI = [2.49, 7.12], P < 0.00001), flunarizine plus routine treatment (mean difference (M-H) = 3.92, 95% CI = [1.36, 11.29], P=0.01), troxerutin plus routine treatment (mean difference (M-H) = 4.79, 95% CI = [2.20, 10.42], P < 0.00001), and routine treatment (mean difference (M-H) = 6.13, 95% CI = [1.48, 25.34], P=0.01). Risk of bias was assessed in 15 trials. One analysis was graded using GRADE and showed poor results. Adverse events were not reported explicitly in all but one trial. Thus, this meta-analysis suggests that YXQN granules may be beneficial for patients with CCCI. However, owing to the poor quality of the clinical trials and small sample sizes, a definite conclusion on the efficacy and safety of YXQN granules cannot be drawn from existing information.

Ultrasonography and magnetic resonance imaging features of kaposiform hemangioendothelioma and tufted angioma.

Kaposiform hemangioendothelioma (KHE) and tufted angioma (TA) primarily occurring in infants are difficult to distinguish. This study evaluated ultrasonography (US) and magnetic resonance imaging (MRI) features of KHE and TA. Pathologically proven TA (n=21) and KHE (n=40 [11 KHE+Kasabach-Merritt phenomenon [KMP]]) occurring between January 2015 and December 2017 were reviewed. US (n=61) and MRI (n=50) findings were retrospectively evaluated. On US, KHE and TA lesions were subcutaneous, while 40% of KHE exhibited an infiltrative pattern extending into adjacent muscles. Of TA lesions, 42.9% were hyperechoic and 96.15% of KHE lesions exhibited mixed echogenicity. Of TA lesions, 76.2% exhibited well-defined margins and all KHE lesions exhibited ill-defined margins. The depth and vascular density of KHE and KHE+KMP were significantly increased compared with TA. The arterial peak systolic blood flow velocity of KHE+KMP was significantly higher than that in TA and KHE. KHE and KHE+KMP were significantly harder than TA on elastography. 3-D color Doppler revealed branch-shape blood flow for KHE and KHE+KMP lesions; for TA, it revealed a dot-like and striped pattern. Considering MRI findings, KHE and KHE+KMP were more likely to exhibit diffuse heterogeneous enhancement after contrast than TA. KHE was infiltrative and more likely to be thick, hypoechoic, ill-defined, richly vascular and hard than TA on US. KHE lesions were subcutaneous and reticular, with heterogeneous enhancement on MRI. Awareness of these features should prompt radiologists in the differential diagnosis of pediatric masses.

Patent ductus arteriosus (PDA) staging and splanchnic circulation in high risk preterm infants

Objective: To evaluate the influence of PDA on superior mesenteric artery (SMA) and celiac artery (CA) in the immediate postnatal period in preterm infants. Methods: 50 preterm less than 32week with birth weight less than 1kg was included in the prospective observation study. PDA (PSV: peak systolic velocity, EDV: end diastolic velocity, TAV: time average velocity). Blood flow indices (resistive index; RI, pulsatility index; PI) was calculated. PDA was categorized as small, moderate and large. Values taken at 48hr were considered for statistical calculation. Result: Significant PDA was associated with high SMA PSV and low EDV in both SMA and CA. Large (n=12) and moderate PDA (n=3) was associated with high PSV and low EDV in SMA, hence was associated with significantly high RI (large; 0.85±0.04, moderate; 0.80±0.03) in mesenteric circulation. In celiac circulation, large PDA was associated with low EDV (11.66±6.09) and moderate PDA was associated with significant high PSV (64.33±13.05). This velocity pattern in CA was associated with significant high RI (0.77±0.08) and high PI (1.73±0.52) in large PDA group. Velocities in small PDA and no PDA groups were comparable in both arteries. Conclusion: Significant PDA was associated with attenuated blood velocities in SMA compromising the intestinal perfusion. Celiac artery blood flow velocities were adversely affected by large PDA. Low EDV is the predicting factor for compromised perfusion in both the arteries. PDA diameter and flow in descending aorta was the determining factor.

The association between NIRS and Doppler ultrasonography in preterm infants with patent ductus arteriosus

Objective: To determine if near-infrared spectroscopy (NIRS), which is easier to obtain than Doppler ultrasonography (USG), may be used in accordance with Doppler USG to provide additional data for assessment of organ blood flow velocities in preterm infants with hemodynamically significant PDA.Study design: Thirty-one infants who were treated with ibuprofen for closure of PDA were monitored continuously with NIRS. Cerebral, mesenteric, and renal arterial blood flow velocities were measured with Doppler USG before and after the treatment.Results: While cerebral, mesenteric, and renal fractional oxygen extraction (FTOE) measurements decreased significantly (p = .042, p < .001, p < .001, respectively), NIRS measurements (p = .016, p < .001, p < .001, respectively) and mean blood flow velocities (p = .003, p = .011, p = .002, respectively) increased significantly after the treatment. There was a significant correlation between pretreatment cerebral and mesenteric FTOE and resistive index (RI) values (r = 0.45, p = .01, and r = 0.46, p = .01, respectively). However, no correlation was observed between renal FTOE values and renal RI (r = 0.33, p = .06). Posttreatment cerebral, renal, and mesenteric FTOE values correlated positively with corresponding RI (r = 0.41, p = .02; r = 0.39, p = .02; r = 0.65, p < 01; respectively). Pretreatment and posttreatment cerebral, mesenteric, and renal FTOE values and arterial mean velocities were inversely correlated (pretreatment: r = 0.69, p < .01; r = 0.72, p < .01; r = 0.77, p < .01; posttreatment: r = 0.54, p = .01; r = 0.69, p < .01; r = 0.38, p = .01; respectively).Conclusion: As Doppler and NIRS measurements correlated significantly, we concluded that NIRS might be used in monitoring organ blood flow in preterm infants with PDA, which may provide additional data for management of this condition.

Opening of ATP-sensitive potassium channels causes migraine attacks: a new target for the treatment of migraine

Migraine is one of the most disabling and prevalent of all disorders. To improve understanding of migraine mechanisms and to suggest a new therapeutic target, we investigated whether opening of ATP-sensitive potassium channels (KATP) would cause migraine attacks. In this randomized, double-blind, placebo-controlled, crossover study, 16 patients aged 18-49 years with one to five migraine attacks a month were randomly allocated to receive an infusion of 0.05 mg/min KATP channel opener levcromakalim and placebo on two different days (ClinicalTrials.gov number, NCT03228355). The primary endpoints were the difference in incidence of migraine attacks, headaches and the difference in area under the curve (AUC) for headache intensity scores (0-12 h) and for middle cerebral artery blood flow velocity (0-2 h) between levcromakalim and placebo. Between 24 May 2017 and 23 November 2017, 16 patients randomly received levcromakalim and placebo on two different days. Sixteen patients (100%) developed migraine attacks after levcromakalim compared with one patient (6%) after placebo (P = 0.0001); the difference of incidence is 94% [95% confidence interval (CI) 78-100%]. The incidence of headache over the 12 h observation period was higher but not significant after levcromakalim (n = 16) than after placebo (n = 7) (P = 0.016) (95% CI 16-71%). The AUC for headache intensity was significantly larger after levcromakalim compared to placebo (AUC0-12h, P < 0.0001). There was no change in mean middle cerebral artery blood flow velocity after levcromakalim compared to placebo (AUC0-2hP = 0.46). Opening of KATP channels caused migraine attacks in all patients. This suggests a crucial role of these channels in migraine pathophysiology and that KATP channel blockers could be potential targets for novel drugs for migraine.

Guidelines for ultrasound examination in ophthalmology. Part III: Color Doppler ultrasonography.

The aim of this article was to present the possibilities of use and application of color-coded Doppler ultrasonography in the diagnosis of various diseases of the eyeball and orbit which result from vascular disorders. Color-coded Doppler ultrasonography is recommended for the assessment of blood flow velocity in the retrobulbar arteries. That is why the article contains current recommendations for Doppler imaging in ophthalmology. The paper provides detailed recommendations for patient’s preparation for the examination, presents the scanning technique and safety of the examination, and lists ophthalmological diseases of vascular origin for which color-coded Doppler ultrasonography can be applied. Furthermore, the article also presents other techniques applied in clinical practice for the assessment of blood flow or imaging of vasculature of a given eyeball structure, inter alia: power Doppler ultrasonography, 3D and 4D ultrasonography, magnetic resonance angiography, spiral computer tomography, transcranial ultrasonography and modern microvascular imaging. The authors emphasize the usefulness of color-coded Doppler ultrasonography in the diagnosis of diseases which result from blood flow disorders within the eyeball, such as amaurosis fugax, ocular ischemic syndrome, insufficiency in vessels supplying the carotid and vertebral arteries, posterior ischemic optic neuropathy, glaucoma, age-related macular degeneration, vascular vision disorders, vascular malformations, such as arteriovenous fistula, orbital varices, systemic connective tissue diseases in retinopathy of prematurity, diabetes, thyroid disorders or strabismus. The application of color-coded Doppler ultrasonography is especially important in the assessment of the vasculature of intrabulbar tumorous lesions and in the differential diagnosis of intrabulbar tumors.

Objective Assessment of Beat Quality in Transcranial Doppler Measurement of Blood Flow Velocity in Cerebral Arteries.

Transcranial Doppler (TCD) ultrasonography measures pulsatile cerebral blood flow velocity in the arteries and veins of the head and neck. Similar to other real-time measurement modalities, especially in healthcare, the identification of high-quality signals is essential for clinical interpretation. Our goal is to identify poor quality beats and remove them prior to further analysis of the TCD signal. We selected objective features for this purpose including Euclidean distance between individual and average beat waveforms, cross-correlation between individual and average beat waveforms, ratio of the high-frequency power to the total beat power, beat length, and variance of the diastolic portion of the beat waveform. We developed an iterative outlier detection algorithm to identify and remove the beats that are different from others in a recording. Finally, we tested the algorithm on a dataset consisting of more than 15 h of TCD data recorded from 48 stroke and 34 in-hospital control subjects. We assessed the performance of the algorithm in the improvement of estimation of clinically important TCD parameters by comparing them to that of manual beat annotation. The results show that there is a strong correlation between the two, that demonstrates the algorithm has successfully recovered the clinically important features. We obtained significant improvement in estimating the TCD parameters using the algorithm accepted beats compared to using all beats. Our algorithm provides a valuable tool to clinicians for automated detection of the reliable portion of the data. Moreover, it can be used as a pre-processing tool to improve the data quality for automated diagnosis of pathologic beat waveforms using machine learning.

Causality analysis reveals the link between cerebrovascular control and acute kidney dysfunction after coronary artery bypass grafting

Background: Patients undergoing coronary artery bypass graft (CABG) surgery might experience postoperative complications and some of them, such as acute kidney dysfunction (AKD), are the likely consequence of hypoperfusion. We hypothesized that an impaired cerebrovascular control is a hallmark of a vascular damage that might favor AKD after CABG. Objective: Our aim is to characterize cerebrovascular control in CABG patients through the assessment of the relationship between mean arterial pressure (MAP) and mean cerebral blood flow velocity (MCBFV) and to check whether markers describing MCBFV-MAP dynamical interactions could identify subjects at risk to develop postoperative AKD. Approach: MAP and MCBFV beat-to-beat series were extracted from invasive arterial pressure and transcranial Doppler recordings acquired simultaneously in 23 patients just before CABG after the induction of propofol general anesthesia. Subjects were divided into AKD group (n = 9, age: 68 ± 9, 8 males) and noAKD group (n = 14, age: 65 ± 8, 12 males) according to whether they developed postoperative AKD or not after CABG. We computed MAP and MCBFV time-domain and spectral markers as well as MCBFV-MAP cross-spectral indexes in very-low-frequency (VLF, 0.02–0.07 Hz), low-frequency (LF, 0.07–0.15 Hz) and high-frequency (HF, 0.15–0.30 Hz) bands. We also calculated model-based transfer entropy (TE) to quantify the degree of MCBFV dependence on MAP and vice versa. The null hypothesis of MCBFV-MAP uncoupling was tested via a surrogate approach associating MAP and MCBFV in different patients. Main results: Time, spectral and cross-spectral markers had a limited power in separating AKD from noAKD individuals. Conversely, TE from MAP to MCBFV was significantly above the level set by surrogates only in AKD groups and significantly larger than that computed in noAKD. Significance: The reduced cerebrovascular autoregulation in AKD patients suggest a vascular impairment likely making them more at risk of hypoperfusion during CABG and AKD after CABG.

Compromised Dynamic Cerebral Autoregulation in Patients With Depression.

Background: Patients with depression tend to have various comorbid neurological symptoms, but the mechanisms remain unclear. The purpose of this study was to analyze the characteristics of dynamic cerebral autoregulation in depressed patients. Methods: Patients (aged ≥ 18 years) who were diagnosed with depression [17-item Hamilton Depression Rating Scale (HAMD) > 17] or suspected of depression (HAMD > 7) were enrolled in this study. Medically healthy volunteers were recruited as controls. The subjects also received the 7-item HAMD. We simultaneously recorded noninvasive continuous arterial blood pressure and bilateral middle cerebral artery blood flow velocity from each subject. Cerebral autoregulation was assessed by analyzing the phase difference using transfer function analysis. Results: This study enrolled 54 patients with suspected depression, 45 patients with depression, and 48 healthy volunteers. The mean phase difference values were significantly lower in the patients with depression (F = 9.071, P < 0.001). In the multiple regression analysis, depression was negatively correlated with the phase difference values. Conclusions: Dynamic cerebral autoregulation was compromised in patients with depression and negatively correlated with the depression score. Improving dynamic cerebral autoregulation may be a potential therapeutic method for treating the neurological symptoms of depression.

Evaluation of pulmonary artery blood flow and right heart function using phase-contrast magnetic resonance imaging in elderly patients with chronic obstructive pulmonary disease

Objective To investigate the value of phase-contrast magnetic resonance imaging(PC-MRI)in evaluating pulmonary artery blood flow and right ventricular(RV)function in elderly patients with chronic obstructive pulmonary disease(COPD). Methods Twenty-four elderly patients with COPD admitted to Beijing Anzhen Hospital between February 2016 and June 2017 were enrolled in this retrospective study.Based on pulmonary artery pressure evaluated by right heart catheterization, COPD patients were divided into a pulmonary hypertension group(PH group, n=12)and a non-PH group(n=12). Pulmonary artery blood flow velocity and volume, pulmonary arterial compliance and right heart function parameters including ejection fraction, end-diastolic volume, end-systolic volume and cardiac output, and 6-min walking distance evaluated by PC-MRI were compared between the two groups. Results There were significant differences in peak flow velocity[(88.1±16.0)cm/s vs.(59.8±13.8)cm/s, P=0.005], flow volume[(80.7±22.0)ml/s vs.(53.2±26.7)ml/s, P=0.012], main pulmonary artery compliance[(42.3±14.6)vs.(22.7±10.8), P=0.001], right ventricular ejection fraction[(48.4±13.4)% vs.(37.6±11.1)%, P=0.000], end-diastolic volume[(64.6±22.5)ml vs.(72.5±22.8)ml, P=0.030]and end-systolic volume[(50.6±33.1)ml vs.(41.7±33.1)ml, P=0.040]between the non-PH and PH groups, while there was no significant difference in cardiac output between the non-PH and PH groups[(34.2±10.8)ml vs.(34.4±8.3)ml, P=0.080]. Pearson's correlation analysis showed that 6-minute walking distance had good correlations with right ventricular ejection fraction(r=0.49), forced expiratory volume in 1 s(FEV1)(r=0.60)and main pulmonary artery diameter(r=-0.61). Conclusions PC-MRI is a noninvasive imaging method for quantitative analysis of pulmonary artery dynamics and right heart function for the elderly with COPD, and it can provide information for evaluating therapeutic effects and prognosis. Key words: Magnetic resonance imaging; Pulmonary disease, chronic obstructive; Pulmonary artery; Ventricular function

Hemodynamics of infants with strong fluctuations of internal cerebral vein.

There is a high incidence of intraventricular hemorrhage in extremely low-birthweight (ELBW) infants of low gestational age with high-grade fluctuations in the perfusion waveform of the internal cerebral vein. This study investigated changes in the hemodynamic status of ELBW infants during initial strong fluctuations in the perfusion waveform of the internal cerebral vein. We evaluated the perfusion waveform of the internal cerebral vein in 192 ELBW infants from birth, every 8h for a total of 120h. Sixty-seven infants had high-grade fluctuations. On the basis of the presence of patent ductus arteriosus (PDA), patients were subdivided into PDA(-) (n=32) and PDA(+) (n=35) groups. During the first high-grade fluctuation, the PDA(-) group had significant increases in systolic, diastolic, and mean blood pressure (P<0.001 for all). The PDA(+) group did not have significant changes in blood pressure but did have significant increases in the number of interruptions or regurgitations of diastolic renal arterial blood flow (P=0.04) and end-diastolic left pulmonary arterial flow velocity (P<0.001), indicating increased left-to-right shunt. Blood pressure elevation may underlie fluctuations in the perfusion waveform of the internal cerebral vein and lead to the first high-grade increases during acute management of ELBW infants. When no elevation in blood pressure occurred, hemodynamically significant PDA was considered a potential underlying factor.

Impaired Cerebral Vasoreactivity Despite Symptom Resolution in Sports-Related Concussion.

Traumatic brain injury (TBI) is associated with increased risk of later-life neurodegeneration and dementia. However, the underpinning mechanisms are poorly understood, and secondary injury resulting from perturbed physiological processes plays a significant role. Cerebral vasoreactivity (CVR), a measure of hemodynamic reserve, is known to be impaired in TBI. However, the temporal course of this physiological perturbation is not established. We examined CVR and clinical symptoms on day 3 (T1), day 21 (T2), and day 90 (T3) after concussion in collegiate athletes and cross-sectionally in non-injured controls. Changes in middle cerebral artery blood flow velocity (MCAV; transcranial Doppler ultrasonography) were measured during changes in end-tidal CO2 (PetCO2) at normocapnia, hypercapnia (inspiring 8% CO2), and hypocapnia (hyperventilation). CVR was determined as the slope of the linear relationship and expressed as percent change in MCAV per mmHg change in PetCO2. CVR was attenuated during the acute phase T1 (1.8 ± 0.4U; p = 0.0001), subacute phases T2 (2.0 ± 0.4U; p = 0.0017), and T3 (1.9 ± 0.6U; p = 0.023) post-concussion compared to the controls (2.3 ± 0.3U). Concussed athletes exhibited higher symptom number (2.5 ± 3.0 vs. 12.1 ± 7.0; p < 0.0001) and severity (4.2 ± 6.0 vs. 29.5 ± 23.0; p < 0.0001), higher Patient Health Questionnaire-9 score (2.2 ± 2.0 vs. 9.1 ± 6.0; p = 0.0003) at T1. However, by T2, symptoms had resolved. We show that CVR is impaired as early as 4 days and remains impaired up to 3 months post-injury despite symptom resolution. Persistent perturbations in CVR may therefore be involved in secondary injury. Future studies with a larger sample size and longer follow-up period are needed to validate this finding and delineate the duration of this vulnerable period.

Transcranial Doppler Non-invasive Assessment of Intracranial Pressure, Autoregulation of Cerebral Blood Flow and Critical Closing Pressure during Orthotopic Liver Transplant

Transcranial Doppler (TCD) ultrasonography allows continuous non-invasive monitoring of cerebral blood flow velocity in a variety of clinical conditions. Recently, signal processing of TCD signals has provided several comprehensive parameters for the assessment of cerebral haemodynamics. In this work, we applied a TCD multimodal approach in patients with acute liver failure undergoing orthotopic liver transplant (OLT) to assess the clinical feasibility of using TCD for cerebral haemodynamics assessment in this setting. We retrospectively studied six patients undergoing OLT with continuous monitoring of arterial blood pressure and blood flow velocity in the middle cerebral artery. The main cerebral haemodynamic parameters assessed were non-invasive intracranial pressure, cerebral perfusion pressure, cerebral autoregulation, pulsatility index, critical closing pressure and diastolic closing margin. TCD monitoring revealed marked alterations of these parameters in the OLT setting, which could provide relevant clinical information when there is imminent risk of neurologic impairment.