Cerebral Blood Flow Velocity Research Articles

Evidence of cortical vascular impairments in early stage of Alzheimer's transgenic mice: Optical imaging.

Alzheimer's disease (AD), a neurodegenerative disorder with progressive cognitive decline, remains clinically challenging with limited understanding of etiology and interventions. Clinical studies have reported vascular defects prior to other pathological manifestations of AD, leading to the "Vascular Hypothesis" for the disorder. However, in vivo assessments of cerebral vasculature in AD rodent models have been constrained by limited spatiotemporal resolution or field of view of conventional imaging. We herein employed two in vivo imaging technologies, Dual-Wavelength Imaging and Optical Coherence Doppler Tomography, to evaluate cerebrovascular reactivity (CVR) to vasoconstrictive cocaine and vasodilatory hypercapnia challenges and to detect resting 3D cerebral blood flow (CBF) in living transgenic AD mice at capillary resolution. Results showed that CVR to cocaine and hypercapnia was significantly attenuated in 7-10 months old AD mice vs controls, indicating reduced vascular flexibility and reactivity. Additionally, in the AD mice, arterial CBF velocities were slower and the microvascular density in cortex was decreased compared to controls. These results reveal significant vascular impairments including reduced CVR and resting CBF in early-staged AD mice. Hence, this cutting-edge in vivo optical imaging offers an innovative venue for detecting early neurovascular dysfunction in AD brain with translational potential.

Relationship between the amplitudes of cerebral blood flow velocity and intracranial pressure using linear and non-linear approach.

Intracranial pressure (ICP), cerebral blood flow and volume are affected by craniospinal elasticity and cerebrospinal fluid dynamics, interacting in complex, nonlinear ways. Traumatic brain injury (TBI) may significantly alter this relationship. This retrospective study investigated the relationship between the vascular and parenchymal intracranial compartments by analysing two amplitudes: cerebral blood flow velocity (AmpCBFV) and ICP (AMP) during hypocapnia manoeuvre in TBI patients. Twenty-nine TBI patients hospitalised at Addenbrooke's Hospital, whose ICP and CBFV were monitored during mild hypocapnia, were included. A linear metric of the relationship was defined as a moving-window correlation (R) between AmpCBFV and AMP, named RAMP. Nonlinear metrics were based on the Joint Symbolical Analysis (JSA) algorithm, which transforms AmpCBFV and AMP into sequences of symbols ('words') using a binary scheme with word lengths of three. The mean AmpCBFV and AMP were not significantly correlated at baseline (r = -0.10) or during hypocapnia (r = -0.19). However, the RAMP index was significantly higher at baseline (0.64 ± 0.04) compared to hypocapnia (0.57 ± 0.04, p = 0.035). The relative frequency of symmetrical word types (JSAsym) describing the AmpCBFV-AMP interaction decreased during hypocapnia (0.35 ± 0.30) compared to baseline (0.44 ± 0.030; p = 0.004). Our results indicate that while the grouped-averaged AmpCBFV and AMP were not significantly correlated, either at baseline or during hypocapnia, significant changes were observed when using RAMP and JSA indices. Further validation of these new parameters, which reflect the association between the vascular and parenchymal intracranial compartments, is needed in a larger cohort.

Pretreatment Cranial Computed Tomography Perfusion Predicts Dynamic Cerebral Autoregulation Changes in Acute Hemispheric Stroke Patients Having Undergone Recanalizing Therapy: A Retrospective Study

Objectives: Blood pressure (BP) management is challenging in patients with acute ischemic supratentorial stroke undergoing recanalization therapy due to the lack of established guidelines. Assessing dynamic cerebral autoregulation (dCA) may address this need, as it is a bedside technique that evaluates the transfer function phase in the very low-frequency (VLF) range (0.02–0.07 Hz) between BP and cerebral blood flow velocity (CBFV) in the middle cerebral artery. This phase is a prognostically relevant parameter, with lower values associated with poorer outcomes. This study aimed to evaluate whether early cranial computed tomography perfusion (CTP) can predict this parameter. Methods: In this retrospective study, 165 consecutive patients with hemispheric strokes who underwent recanalizing therapy were included (median age: 73 years; interquartile range (IQR) 60–80; women: 43 (26%)). The cohort comprised 91 patients treated with intravenous thrombolysis (IV-lysis) alone (median National Institute of Health Stroke Scale (NIHSS) score: 5; IQR 3–7) and 74 patients treated with mechanical thrombectomy (median NIHSS: 15; IQR 9–18). Regression analysis was performed to assess the relationship between pretreatment CTP-derived ischemic penumbra and core stroke volumes and the dCA VLF phase, as well as CBFV assessed within the first 72 h post-stroke event. Results: Pretreatment penumbra volume was a significant predictor of the VLF phase (adjusted r2 = 0.040; β = −0.001, 95% confidence interval (CI): −0.0018 to −0.0002, p = 0.02). Core infarct volume was a stronger predictor of CBFV (adjusted r2 = 0.082; β = 0.205, 95% CI: 0.0968–0.3198; p = 0.0003) compared to penumbra volume (p = 0.01). Additionally, in the low-frequency range (0.07–0.20 Hz), CBFV and BP were inversely related to the gain, an index of vascular tone. Conclusion: CTP metrics appear to correlate with the outcome-relevant VLF phase and reactive hyperemic CBFV, which interact with BP to influence vascular tone and gain. These aspects of dCA could potentially guide BP management in patients with acute stroke undergoing recanalization therapy. However, further validation is required.

Cerebral Blood Flow Dynamics in Neurogenic Orthostatic Hypotension: A Systematic Review and Meta-Analysis.

Neurogenic orthostatic hypotension (nOH) causes pathological falls in standing blood pressure that may or may not be symptomatic. nOH also raises the risk of poor neurological outcomes irrespective of symptom presence, possibly reflecting subclinical cerebral hypoperfusion. Dynamic changes in cerebral blood flow velocity (CBFv) help infer how blood pressure fluctuations influence CBFv and cerebral autoregulation. Whether CBFv is impacted in nOH relative to related conditions without nOH and healthy controls (HC) remains unresolved. Whether nOH symptoms reflect greater CBFv falls is also unclear. This review aimed to compare CBFv between nOH and HC, nOH and disease-matched controls (eg, Parkinson disease±nOH), and between symptomatic and asymptomatic nOH. Embase and MEDLINE were searched up to April 2024. Means, SDs, and sample sizes for supine and upright CBFv were extracted to generate standardized effect sizes (Hedge g). Random-effects modeling compared postintervention between-group effect sizes. Seventeen studies were included for review. Thirteen studies were suitable for meta-analysis comparing nOH to HC, 2 comparing disease-matched controls to nOH and to HC, and 3 for symptomatic comparisons. Compared with HC, nOH had larger drops in CBFv (Hedge g, -0.64 [95% CI, -0.85 to -0.44]; P<0.001). CBFv falls between nOH and disease-matched controls were similar (P=0.17). Symptomatic nOH had larger CBFv drops (Hedge g, 0.84 [95% CI, 0.212-1.461]; P=0.009) than asymptomatic nOH. nOH causes significant orthostatic reductions in CBFv compared with HC, and symptomatic patients experience greater falls in CBFv than asymptomatic patients. Recognizing the clinical implications of CBFv in nOH is crucial for mitigating adverse outcomes.

Retinal blood vessel diameter changes with 60-day head-down bedrest are unaffected by antioxidant nutritional cocktail

Long-term human spaceflight can lead to cardiovascular deconditioning, but little is known about how weightlessness affects microcirculation. In this study, we examined how the retinal microvessels and cerebrovascular regulation of 19 healthy male participants responded to long-term head-down bedrest (HDBR), an earth-based analog for weightlessness. In addition, we examined whether an anti-inflammatory/antioxidant cocktail could prevent the vascular changes caused by HDBR. In all study participants, we found a decrease in retinal arteriolar diameter by HDBR day 8 and an increase in retinal venular diameter by HDBR day 16. Concurrently, blood pressure at the level of the middle cerebral artery and the cerebrovascular resistance index were higher during HDBR, while cerebral blood flow velocity was lower. None of these changes were reversed in participants receiving the anti-inflammatory/antioxidant cocktail, indicating that this cocktail was insufficient to restore the microvascular and cerebral blood flow changes induced by HDBR.

Intermittent hypoxia training improves cerebral blood flow without cognitive impairment.

Brief exposure to intermittent hypoxia has been shown to potentially induce protective effects in the body. Animal studies suggest that intermittent hypoxia could increase cerebral blood flow and confer resistance to subsequent hypoxic-ischemic injury, yet clinical investigations are limited. This study aimed to evaluate the impact of a moderate short-term intermittent hypoxia protocol on cerebral blood flow and cognitive performance. Subjects who met the inclusion criteria were recruited to this study and randomized into the intermittent hypoxia group or the control group, which receives intermittent hypoxia training and sham-intermittent hypoxia training, respectively. Cerebral hemodynamics, cognitive performance, cerebral perfusion pressure, and oxygen saturation were assessed before and after the intervention. A total of 100 healthy participants were included in this study. Compared to the control group, the intermittent hypoxia group exhibited higher peak systolic blood flow velocity (108.64 ± 22.53 vs. 100.21 ± 19.06, p = 0.049) and cerebrovascular conduction index (0.74 ± 0.17 vs. 0.66 ± 0.21, p = 0.027), and lower cerebrovascular resistance index (1.41 ± 0.29 vs. 1.54 ± 0.36, p = 0.044) following intermittent hypoxia training. Additionally, within-group comparisons revealed that intermittent hypoxia training led to increased cerebral blood flow velocity, elevated cerebrovascular conductance index, and decreased cerebrovascular resistance index (p < 0.05). Other indicators including cognitive function, cerebral perfusion pressure, and oxygen saturation did not exhibit significant differences between groups. These findings revealed that intermittent hypoxia may represent a safe and effective strategy for improving cerebral blood flow.

Correlation between antihypertensive drugs and cerebral hemodynamic parameters: insights from observational findings using transcranial Doppler.

Antihypertensives (AHD) can influence cerebral autoregulation (CA) and attenuate hypertrophic concentric remodelling of arterioles. The aim of this study was to examine the associations between AHD, CA and structural and functional properties of cerebral arteries. In this observational, cross-sectional study 115 volunteers were divided in group 1 (non-hypertensive) [n = 30]; group 2 (hypertensive with systolic blood pressure [SBP] < 140 and diastolic blood pressure [DBP] < 90 mmHg) [n = 54]; group 3 (hypertensive with SBP ≥ 140 or DBP ≥ 90 mmHg) [n = 31] and simultaneous measurements of systemic blood pressure (BP) and middle cerebral artery blood flow velocity (CBFV) were obtained from digital plethysmography and transcranial Doppler. Beat-to-beat, critical closing pressure (CrCP), resistance-area product (RAP) and autoregulation index (ARI) values were extracted by linear regression analysis of instantaneous BP and CBFV waveforms using computerised analysis. Pulsatility index (PI) was calculated and CO2 reactivity was assessed by the breath-holding test. Despite their higher RAP (1.7 [±0.7], p < 0.001) compared to groups 1 and 2, uncontrolled hypertensive using diuretics (p = 0.047) and α2-agonists (p = 0.009) had significantly lower PI. Impaired CO2 reactivity was common between the two hypertensive groups (p = 0.008), however ARI, CrCP and CBFV did not differ between them and non-hypertensive individuals and also did not correlate with any AHD used. Unlike the RAP, PI does not seem to reflect the real cerebrovascular resistence resulting from chronic arterial remodelling. Despite impaired CO2 reactivity, hypertensivehavearterial tonus and CA comparable to non-hypertensive. Experimental studies involving an untreated hypertensive control group are required to robustly make definitive conclusions about these questions.

Cerebral Overperfusion Despite Reduced Cortical Metabolism Is Associated with Postoperative Delirium in Cardiac Surgery Patients: A Prospective Observational Study.

Background: Decreased cerebral oximetry (rSO2) in cardiac surgery is associated with postoperative delirium (POD). However, interventions optimizing intraoperative rSO2 are inconclusive. Methods: In this prospective observational cohort study, the relationship between rSO2, middle cerebral artery blood flow velocity (MCAV), and processed EEG was assessed in cardiac surgery patients with and without POD. MCAV was continuously recorded by transcranial Doppler sonography (TCD), together with continuous rSO2 and bispectral index (BIS) monitoring. Cardiopulmonary bypass (CPB) flow rate was adjusted according to body surface area. The cohort was divided into the POD and control groups, according to the postoperative results of the confusion assessment method (CAM/CAM-ICU), the 4A's test (4AT), and the Delirium Observation Scale (DOS). A mixed model analysis was performed for intraoperative raw data. The cerebral autoregulation index was calculated from TCD, rSO2, and arterial pressure values. Differences in impaired autoregulation were compared using the Mann-Whitney U test. Results: A total of 41 patients were included in this study. A total of 13 patients (36.11%) developed postoperative delirium. There were no significant differences in the baseline characteristics of patients with or without POD. Patients with POD had lower BIS values during CPB (adjusted mean difference -4.449 (95% CI [-7.978, -0.925])). RSO2 was not significantly reduced in POD, (adjusted mean difference: -5.320, 95% CI [-11.508, 0.874]). In contrast, MCAV was significantly increased in POD (10.655, 95% CI [0.491, 20.819]). The duration of cerebral autoregulation impairment did not differ significantly for TCD and cerebral oximetry-derived indices (p = 0.4528, p = 0.2715, respectively). Conclusions: Our results suggest that disturbed cerebral metabolism reflects a vulnerable brain which may be more susceptible to overperfusion during CPB, which can be seen in increased MCAV values. These phenomena occur irrespectively of cerebral autoregulation.

Autoregulatory dysfunction in adult Moyamoya disease with cerebral hyperperfusion syndrome after bypass surgery

Cerebral hyperperfusion syndrome (CHS) is a serious complication after bypass surgery in Moyamoya disease (MMD), with autoregulatory dysfunction being a major pathogenesis. This study investigated the change of perioperative autoregulation and preoperative prognostic potentials in MMD with postoperative CHS. Among 26 hemispheres in 24 patients with adult MMD undergoing combined bypass, 13 hemispheres experienced postoperative CHS. Arterial blood pressure and cerebral blood flow velocity were perioperatively measured with transcranial Doppler ultrasound during resting and the Valsalva maneuver (VM). Autoregulation profiles were discovered in both the CHS and non-CHS groups using mean flow index (Mxa), VM Autoregulatory Index (VMAI), and a new metric termed VM Overshooting Index (VMOI). The CHS group had inferior autoregulation than the non-CHS group as indicated by VMOI on preoperative day 1 and postoperative 3rd day. Deteriorated autoregulation was observed via Mxa in the CHS group than in the non-CHS group on the postoperative 3rd and discharge days. Postoperative longitudinal autoregulation recovery in the CHS group was found in a logistic regression model with diminished group differences over the time course. This work represents a step forward in utilizing autoregulation indices derived from physiological signals, to predict the postoperative CHS in adult MMD.

Effects of 30-Day Midodrine Administration, Compared to Placebo, on Blood Pressure, Cerebral Blood Flow Velocity, and Cognitive Performance in Persons with SCI.

Individuals with spinal cord injury (SCI) at and above T6 experience impaired descending cortical control of the autonomic nervous system, which predisposes them to blood pressure (BP) disorders including persistent hypotension. The primary aim of this investigation was to determine the effects of midodrine, 10 mg, administered daily over a 30-day period in the home environment, compared to placebo, on laboratory assessments of BP, cerebral blood flow velocity (CBFv), and cognitive performance in hypotensive individuals with chronic SCI. This prospective, randomized, placebo-controlled, double-blind, crossover trial was conducted in 15 individuals with tetraplegia. In the first 30-day period, five participants were randomized to midodrine and 10 were randomized to placebo; participants were then crossed over to the second 30-day period following a 14-day washout. Laboratory assessments of BP, CBFv, and cognitive performance were measured before and after each of the two study arms. Systolic BP (SBP) was significantly increased following midodrine administration compared to placebo (116 ± 23 mm Hg vs 94 ± 16 mm Hg; p = .002). In addition, diastolic CBFv was increased after midodrine administration compared to placebo (31.0 ± 11.2 vs 25.6 ± 9.1 cm/s; p = .04). However, there were no significant drug by time interaction effects for systolic or mean CBFv (p > .172) and cognitive performance (p = .689). The results suggest significant increases in SBP and diastolic CBFv without appreciable effects on cognition after 30 days of midodrine administration. Further investigation is needed to identify effective antihypotensive treatment options that not only normalize BP but also improve CBFv and cognition.

Orthostatic intolerance with tachycardia (postural tachycardia syndrome) and without (hypocapnic cerebral hypoperfusion) represent a spectrum of the same disorder.

Spectrum of chronic orthostatic intolerance without orthostatic hypotension includes postural tachycardia syndrome (POTS), with orthostatic tachycardia and hypocapnic cerebral hypoperfusion (HYCH), without orthostatic tachycardia. This study compared autonomic, cerebrovascular, and neuropathic features of POTS and HYCH. This retrospective study evaluated patients with orthostatic intolerance referred for autonomic testing. Analyzed data included surveys (Survey of Autonomic Symptoms, Compass-31, Neuropathy Total Symptom Score-6, Central Sensitization Inventory) and autonomic tests (Valsalva maneuver, deep breathing, sudomotor and tilt tests), cerebrovascular (cerebral blood flow velocity (CBFv) monitoring in the middle cerebral artery), respiratory (capnography), neuropathic (skin biopsies for assessment of small fiber neuropathy) and invasive cardiopulmonary exercise testing (iCPET). A total of 127 HYCH, 125 POTS, and 42 healthy controls were analyzed. Compared HYCH to POTS patients, there was no difference in the duration of symptoms, the prevalence of younger women, comorbidities, sensory and autonomic complaints, central sensitization syndrome, supine/standing norepinephrine levels, inflammatory markers and medical therapy except for gastrointestinal medication. Autonomic testing showed widespread but similar abnormalities in POTS and HYCH that included: reduced orthostatic CBFv and end-tidal CO2, preload failure (assessed in 16/19 POTS/HYCH), mild autonomic failure, and frequent small fiber neuropathy. HYCH and POTS are syndromes of orthostatic intolerance with cerebral hypoperfusion associated with reduced orthostatic cerebral blood flow, hypocapnia, mild autonomic failure and small fiber neuropathy of a similar degree and distribution; except for tachycardia in POTS. Similarities in peripheral domain abnormalities that affect heart rate suggest that orthostatic tachycardia in POTS is driven by the central nervous system overcompensation of orthostatic challenge. These findings provide additional evidence that HYCH and POTS represent a spectrum of the same disorder. Reduced orthostatic cerebral blood flow is a key unifying feature of HYCH and POTS.

Effect of Dexmedetomidine Versus Propofol Sedation on The Cerebral Blood Flow Velocity and Cerebral Metabolic Rate of Oxygen in Patients With Traumatic Brain Injuries

Effect of Dexmedetomidine Versus Propofol Sedation on The Cerebral Blood Flow Velocity and Cerebral Metabolic Rate of Oxygen in Patients With Traumatic Brain Injuries

Intraoperative transfontanelle ultrasonography for pediatric patients.

Cerebral blood flow (CBF) plays a vital role in delivering cerebral oxygen, and the accurate assessment of CBF is crucial for the intraoperative management of critically ill infants. Although the direct measurement of CBF is challenging, CBF velocity (CBFV) can be assessed using transcranial Doppler. Recent advances in point-of-care ultrasound have introduced brain ultrasound as a feasible intraoperative option, in which transfontanelle ultrasonography (TFU) has been applied to measure the CBFV through the anterior fontanelle. However, the intraoperative application of TFU in pediatric patients remains limited. The present review highlights the procedural aspects and clinical applications of TFU for anesthetic and intensive care management in pediatric patients. TFU facilitates the visualization of cerebral vessels and allows a noninvasive assessment of cerebral hemodynamics. The clinical significance of TFU involves its usefulness in various clinical scenarios, including monitoring CBF during cardiac surgery, assessing fluid responsiveness, and estimating intracranial pressure. TFU also enables the detection of cerebral emboli and the evaluation of anatomical abnormalities such as hydrocephalus or intracranial hemorrhage. TFU has demonstrated potential as an invaluable tool in pediatric care, despite limited familiarity among anesthesiologists. Additional research is needed to explore the associations between CBF and clinical outcomes, focusing on autoregulation, the impact of physiological changes, the associations of TFU findings with other brain monitoring tools such as electroencephalography, cerebral oximetry, and the implications of microemboli. TFU is a significant advancement and valuable tool for noninvasively assessing cerebral hemodynamics and CBF in pediatric patients with open fontanelles.

Ventilatory response to head-down-tilt in healthy human subjects.

Postural fluid shifts may directly affect respiratory control via a complex interaction of baro- and chemo-reflexes, and cerebral blood flow. Few data exist concerning the steady state ventilatory responses during head-down tilt. We examined the cardiorespiratory responses during acute 50° head-down tilt (HDT) in 18 healthy subjects (mean [SD] age 27 [10] years). Protocol 1 (n=8, two female) was 50° HDT from 60° head-up posture sustained for 10min, while exposed to normoxia, normoxic hypercapnia (5% CO2), hypoxia (12% inspired O2) or hyperoxic hypercapnia (95% O2, 5% CO2). Protocol 2 (n=10, four female) was 50° HDT from supine, sustained for 10min, while breathing either medical air or normoxic hypercapnic (5% CO2) gas. Ventilation ( , pneumotachograph), end-tidal O2 and CO2 concentration and blood pressure (Finapres) were measured continuously throughout each protocol. Middle cerebral artery blood flow velocity (MCAv; transcranial Doppler) was also measured during protocol 2. Ventilation increased significantly (P<0.05) compared to baseline during HDT in both hyperoxic hypercapnia (protocol 1 by mean [SD] 139 [26]%) and normoxic hypercapnia (protocol 1 by mean [SD] 131 [21]% and protocol 2 by 129 [23]%), despite no change in or from baseline. No change in was observed during HDT with medical air or hypoxia, and there was no significant change in MCAv during HDT compared to baseline. The absence of change in cerebral blood flow leads us to postulate that the augmented ventilatory response during steep HDT may involve mechanisms related to cerebral venous pressure and venous outflow.

Transcranial Doppler ultrasound in evaluating cerebral blood flow abnormalities in major depressive disorder.

Previous research has shown that blood flow abnormalities affect major depressive disorder (MDD) from multiple perspectives. Therefore, this study aims to investigate the relationship between middle cerebral artery (MCA) blood flow velocity parameters and clinical symptom scores (Hamilton Depression Rating Scale [HAMD] and Montgomery-Åsberg Depression Rating Scale [MADRS]) in patients with MDD. We compared the MCA blood flow velocity parameters, including peak systolic velocity (MCA-PSV), end-diastolic velocity (MCA-EDV), and mean velocity (MCA-MV), between 50 MDD patients and 50 control subjects. Additionally, we analyzed the correlation between these parameters and HAMD and MADRS scores. Hemodynamic parameters such as pulsatility index and resistance index were also compared between the 2 groups. MCA-PSV, MCA-EDV, and MCA-MV were significantly lower in MDD patients compared to the control group, while pulsatility index and resistance index were significantly higher. Correlation analysis revealed that MCA-PSV, MCA-EDV, and MCA-MV were significantly negatively correlated with HAMD and MADRS scores in MDD patients, indicating that cerebral blood flow velocity decreases as depressive symptoms worsen. Furthermore, regression analysis confirmed the negative relationship between blood flow velocity parameters and clinical symptom scores. The results of this study suggest that the reduction in cerebral blood flow velocity in MDD patients may be associated with the severity of depressive symptoms. This finding provides new insights into the pathophysiological mechanisms of MDD and offers a potential theoretical basis for developing depression treatment strategies based on cerebral blood flow velocity parameters.

Revising the Interpretation of Transcranial Doppler Ultrasound Examinations in Pediatric Cerebral Malaria.

Cerebral malaria (CM) is a devastating disease globally. Transcranial Doppler ultrasound (TCD) has identified five different phenotypes of deranged cerebrovascular hemodynamics in children with CM, each associated with different outcomes. For TCD to be used as a point of care neurodiagnostic and neuromonitoring tool in CM patients, proper interpretation of examinations is paramount. Comparison of measured cerebral blood flow velocities (CBFVs) to age-matched normative values is needed to interpret any pediatric TCD study. Until recently, normative values in African children did not exist, so previous work reported the frequency of CM phenotypes by classifying studies compared with normative values of European children. Now that normative TCD values in healthy African children have been established, we performed this retrospective analysis of prospectively collected data to determine phenotype frequency and associated outcomes in children with CM by comparing CBFV values to these contemporary controls.

Utility of doppler ultrasound in early-onset neonatal sepsis: A case-control study.

Early-onset sepsis is one of the leading causes of neonatal morbidity and mortality worldwide and timely diagnosis is, therefore, of paramount importance. As there is a lack of literature regarding early alteration of the cerebral blood flow (CBF) in neonatal sepsis, our study aimed to appraise changes in the CBF velocities and Doppler indices in neonates with early-onset neonatal sepsis (EONS) and to assess its diagnostic accuracy. A total of 99 neonates were recruited in the study; 56 neonates with EONS, and the age-matched 43 neonates without any manifestations of sepsis. A Transcranial Doppler examination and cerebral hemodynamics were assessed in neonates during the first seventy-two hours of life. Doppler indices and CBFV were measured in the anterior cerebral artery (ACA), and middle cerebral artery (MCA), of either side. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated. A significantly lower resistance in Resistivity (RI) and Pulsatility (PI) indices, a significant high end-diastolic velocity (EDV), and relatively higher peak systolic velocity (PSV) in both ACA and MCA have been documented within 72 hours of birth in neonates with EONS compared to the control group of neonates without sepsis. Our Study revealed that assessment of CBF at early hours of birth by Transcranial Doppler examination showed alteration in cerebral hemodynamics in neonates with EONS with an increase in the CBF and a decrease in the resistance. It can be adopted as a bedside, noninvasive tool with immediate diagnostic value.

Role of Transcranial Doppler Ultrasound in Early Assessment of Acute Post Traumatic Brain Injury

Abstract Introduction Traumatic brain injury (TBI) is a global health and socioeconomic problem. It is responsible of millions of ED visits, hospitalizations, and deaths with lifelong disability among survivors. Immediately after TBI, cerebral blood flow (CBF) is extremely low approaching the ischemic thresholds. Concurrently, CBF velocities become strongly correlated to CBF itself. Identification of such disturbances can predict outcome in TBI when assessed early post- injury using Transcranial Doppler (TCD). TCD provides non-invasive real time measurements of CBF velocities as well as pulsatility index (PI). Design Observational prospective cohort study. Setting Helwan university hospital. Aim to assess the accuracy of transcranial Doppler ultrasound as an early predictor of secondary neurological deterioration after acute post traumatic brain injury Patients and Methods 55 patients of acute post traumatic brain injury underwent TCD within 8 hours post trauma. Middle cerebral artery (MCA) velocities and pulsatility index, as well as GCS and initial CT findings, were recorded. The primary end point was the development of secondary neurological deterioration (SND) at day 7 after injury. Secondary outcome measures were the in-hospital mortality and hospital length of stay. Results There was a significant relation between end diastolic velocity (EVD) as well as PI with SND at day 7 as well as GOSE at day 28 post-trauma. There was also significant correlation between PI and hospital mortality. Conclusion TCD, when done early after admission, is useful in identifying patients at risk for developing neurological deterioration after TBI. EDV and PI are good predictors of SND at one week.as well as in-hospital mortality.

Utility of Doppler Ultrasound in Early-Onset Neonatal Sepsis

Abstract Background Early-onset sepsis is one of the leading causes of neonatal morbidity and mortality worldwide and timely diagnosis is, therefore, of paramount importance. There is paucity of literature regarding early alteration of the cerebral blood flow (CBF) in neonatal sepsis. Purpose Our study aimed to appraise changes in the CBF velocities and Doppler indices in neonates with early-onset neonatal sepsis (EONS) and to assess its diagnostic accuracy. Methods A total of 99 neonates were recruited in the study; 56 neonates with EONS, and the age-matched 43 neonates without any manifestations of sepsis. A Transcranial Doppler examination was performed and the cerebral hemodynamics assessed in neonates during the first seventy-two hours of life. Doppler indices and CBFV were measured in the anterior cerebral artery (ACA), and middle cerebral artery (MCA), of either side for the peak systolic velocity (PSV), end-diastolic velocity (EDV), resistivity index (RI), and pulsatility index (PI). Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated for the appropriate diagnostic cut-off points. Results A highly significant lower resistance (PI and RI), relatively higher peak systolic velocity, and higher end-diastolic velocity in both ACA, and MCA have been documented within 72 hours of birth in neonates with EONS compared to the control group of neonates without sepsis. Conclusions Our Study revealed that assessment of CBF at early hours of birth by Transcranial Doppler examination showed alteration in cerebral hemodynamics in neonates with EONS with an increase in the CBF and a decrease in the resistance. It can be adopted as a bedside and noninvasive tool.

Comparison of inhalational and intravenous anesthesia induction on electroencephalogram and cerebral perfusion in children with congenital heart disease: A secondary analysis of a randomized controlled trial

ObjectiveThe effects of anesthetics on electroencephalograms and cerebral perfusion remain understudied in children with congenital heart disease. With regard to this, we compared inhalational anesthesia induction and intravenous anesthesia induction. DesignA randomized controlled trial. SettingOperation room in two tertiary hospitals. ParticipantsA cohort of 116 pediatrics patients undergoing cardiac surgery. Measurements and main resultsThe patients were randomly assigned to either the intravenous group (n=58) or the inhalational group (n=58). The inhalational group received anesthesia induction with 4-6% sevoflurane and a bolus of pipecuronium 0.2 mg/kg, while the intravenous group received anesthesia induction with intravenous midazolam 0.2 mg/kg, pipecuronium 0.2 mg/kg, and sufentanil 1 μg/kg. Ten minutes after tracheal intubation, the following parameters were measured: spectral edge frequency, burst suppression event, patient state index, middle cerebral artery blood flow velocity, cerebral oxygen saturation, and hemodynamic parameters. In comparison to the intravenous group, the inhalational group exhibited significant increases in 95% spectral edge frequency, ratio of burst suppression event, blood flow velocity in the middle cerebral artery, and cerebral oxygen saturation (P<0.05 for all), as well as decreases in systolic pressure, diastolic pressure, cardiac index, and the maximal slope of systolic upstroke (P<0.05 for all). ConclusionThe administration of sevoflurane for anesthesia induction results in more burst suppression, while also demonstrating superior cerebral perfusion when compared to the use of intravenous medications for anesthesia induction.