The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Udo M. Illievich - One of the best experts on this subject based on the ideXlab platform.
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A comparison of propofol and sevoflurane anaesthesia: effects on aortic blood Flow Velocity and middle cerebral artery blood Flow Velocity
Anaesthesia, 2003Co-Authors: A. Holzer, Andrew Donner, W. Winter, Manfred Greher, J. Stark, M. Reddy, Michael Zimpfer, Udo M. IllievichAbstract:Summary We compared systemic (aortic) blood Flow and cerebral blood Flow Velocity in 30 patients randomly allocated to receive either propofol or sevoflurane anaesthesia. Cerebral blood Flow Velocity (CBFv) was measured in the middle cerebral artery using transcranial Doppler. Systemic blood Flow Velocity (SBFv) was measured in the aorta using transthoracic Doppler sonography at the level of the aortic valve. Bispectral index (BIS) was used to measure the depth of anaesthesia. Measurements were made in the awake patient and repeated during propofol or sevoflurane anaesthesia, with BIS measurements of 40–50. The effects of SBFv on CBFv were estimated by calculating the cerebral/systemic blood Flow Velocity-index (CsvI). A CsvI value of 100 indicating a 1 : 1 relationship between CBFv and SBFv. The results demonstrated that propofol anaesthesia produced a significantly greater reduction in CsvI than did sevoflurane anaesthesia [propofol: 60 (19); sevoflurane: 83 (16), p = 0.009, t-test]. This suggests a direct reduction in CBFv independent of SBFv during propofol anaesthesia. The greater reduction of CBFv occurring during propofol anaesthesia may be due to lower cerebral metabolic demand compared with sevoflurane anaesthesia at comparable depths of anaesthesia.
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Influence of aortic blood Flow Velocity on changes of middle cerebral artery blood Flow Velocity during isoflurane and sevoflurane anaesthesia.
European Journal of Anaesthesiology, 2001Co-Authors: A. Holzer, Hubert Hetz, Andrew Donner, Harald Heinzl, Manfred Greher, Harald Standhardt, Michael Zimpfer, Udo M. IllievichAbstract:Summary Background and objective We studied the influence of systemic (aortic) blood Flow Velocity on changes of cerebral blood Flow Velocity under isoflurane or sevoflurane anaesthesia. Methods Forty patients (age: isoflurane 24–62 years; sevoflurane 24–61 years; ASA I–III) requiring general anaesthesia undergoing routine spinal surgery were randomly assigned to either group. Cerebral blood Flow Velocity was measured in the middle cerebral artery by transcranial Doppler sonography (depth: 50–60 mm). Systemic blood Flow Velocity was determined by transthoracic Doppler sonography at the aortic valve. Heart rate, arterial pressure, arterial oxygen saturation and body temperature were monitored. After standardized anaesthesia induction (propofol, remifentanil, vecuronium) sevoflurane or isoflurane were used as single agent anaesthetics. Cerebral blood Flow Velocity and systemic blood Flow Velocity were measured in the awake patient (baseline) and repeated 5 min after reaching a steady state of inspiratory and end-expiratory concentrations of 0.75, 1.00, and 1.25 mean alveolar concentrations of either anaesthetic. To calculate the influence of systemic blood Flow Velocity on cerebral blood Flow Velocity, we defined the cerebral–systemic blood Flow Velocity index (CSvI). CSvI of 100% indicates a 1:1 relationship of changes of cerebral blood Flow Velocity and systemic blood Flow Velocity. Results Isoflurane and sevoflurane reduced both cerebral blood Flow Velocity and systemic blood Flow Velocity. The CSvI decreased significantly at all three concentrations vs. 100% (isoflurane/sevoflurane: 0.75 MAC: 85 ± 25%/81 ± 23%, 1.0 MAC: 79 ± 19%/74 ± 16%, 1.25 MAC: 71 ± 16%/79 ± 21%; [mean ± SD]P = 0.0001). Conclusions The reduction of the CSvI vs. 100% indicates a direct reduction of cerebral blood Flow Velocity caused by isoflurane/sevoflurane, independently of systemic blood Flow Velocity.
Takenobu Kamada - One of the best experts on this subject based on the ideXlab platform.
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Analysis of pulmonary venous Flow Velocity patterns in hypertensive hearts: its complementary value in the interpretation of mitral Flow Velocity patterns.
American heart journal, 1992Co-Authors: Tohru Masuyama, Jung-myung Lee, Kazuhiro Yamamoto, Jun Tanouchi, Masatsugu Hori, Takenobu KamadaAbstract:Although the Doppler mitral Flow Velocity pattern changes in accordance with the degree of left ventricular diastolic dysfunction, it is “normalized” in the presence of heart failure. In this study the pulmonary venous Flow Velocity pattern was characterized in 43 hypertensive patients with and without heart failure to clarify whether analysis of the pulmonary venous Flow Velocity pattern provides complementary information in the interpretation of the mitral Flow Velocity pattern. The mitral Flow Velocity pattern in 32 hypertensive patients without heart failure was characterized by decreases in the peak early diastolic filling Velocity (E) and the ratio of E to peak filling Velocity at atrial contraction. The mitral Flow Velocity pattern was “normalized” in 11 patients with heart failure, with no differences in any mitral Flow Velocity pattern indexes as compared with 24 normal subjects. The pulmonary venous Flow Velocity pattern in hypertensive patients without heart failure was characterized by a decreased peak diastolic forward Flow Velocity (D) and an increased ratio of peak systolic forward Flow Velocity (S) to D (SD ratio). In patients with heart failure, D was higher and the SD ratio was lower compared with hypertensive patients without heart failure (p < 0.01, p < 0.01) and normal subjects (p < 0.01, p < 0.01). Thus the pulmonary venous Flow Velocity pattern appeared to be more reliable than the mitral Flow Velocity pattern in differentiating subgroups of patients with hypertension. Analysis of the pulmonary venous Flow Velocity pattern in conjunction with the mitral Flow Velocity pattern provides important and complementary information in the interpretation of the mitral Flow Velocity pattern in hypertensive patients with and without heart failure.
Ardon Rubinstein - One of the best experts on this subject based on the ideXlab platform.
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Retinal blood Flow Velocity in metabolic syndrome
Graefes Archive for Clinical and Experimental Ophthalmology, 2013Co-Authors: Shay Gutfreund, Marianna Yaron, Zvia Burgansky-eliash, Elena Izkhakov, Hanny Yeshua, Russell Pokroy, Adiel Barak, Ardon RubinsteinAbstract:Background Metabolic syndrome (MetS) is characterized by obesity, insulin resistance, dyslipidemia, and hypertension. The Retinal Function Imager (RFI) is a new technique for measuring retinal blood-Flow Velocity. This study aims to compare retinal blood Flow Velocity between MetS and healthy subjects.
Zvia Burgansky-eliash - One of the best experts on this subject based on the ideXlab platform.
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Segmental reproducibility of retinal blood Flow Velocity measurements using retinal function imager
Graefe's Archive for Clinical and Experimental Ophthalmology, 2013Co-Authors: Jay Chhablani, Zvia Burgansky-eliash, Sami S. Rezeq, Lingyun Cheng, Sunir J. Garg, Rayan A. Alshareef, Laura Gomez, Dirk-uwe Bartsch, William R. FreemanAbstract:Background To evaluate the reproducibility of blood Flow Velocity measurements of individual retinal blood vessel segments using retinal function imager (RFI). Methods Eighteen eyes of 15 healthy subjects were enrolled prospectively at three centers. All subjects underwent RFI imaging in two separate sessions 15 min apart by a single experienced photographer at each center. An average of five to seven serial RFI images were obtained. All images were transferred electronically to one center, and were analyzed by a single observer. Multiple blood vessel segments (each shorter than 100 μm) were co-localized on first and second session images taken at different times of the same fundus using built-in software. Velocities of corresponding segments were determined, and then the inter-session reproducibility of Flow Velocity was assessed by the concordance correlation co-efficient (CCC), coefficient of reproducibility (CR), and coefficient of variance (CV). Results Inter-session CCC for Flow Velocity was 0.97 (95% confidence interval (CI), 0.966 to 0.9797). The CR was 1.49 mm/sec (95% CI, 1.39 to 1.59 mm/sec), and CV was 10.9%. The average arterial blood Flow Velocity was 3.16 mm/sec, and average venous blood Flow Velocity was 3.15 mm/sec. The CR for arterial and venous blood Flow Velocity was 1.61 mm/sec and 1.27 mm/sec respectively. Conclusion RFI provides reproducible measurements for retinal blood Flow Velocity for individual blood vessel segments, with 10.9% variability.
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Retinal blood Flow Velocity in metabolic syndrome
Graefes Archive for Clinical and Experimental Ophthalmology, 2013Co-Authors: Shay Gutfreund, Marianna Yaron, Zvia Burgansky-eliash, Elena Izkhakov, Hanny Yeshua, Russell Pokroy, Adiel Barak, Ardon RubinsteinAbstract:Background Metabolic syndrome (MetS) is characterized by obesity, insulin resistance, dyslipidemia, and hypertension. The Retinal Function Imager (RFI) is a new technique for measuring retinal blood-Flow Velocity. This study aims to compare retinal blood Flow Velocity between MetS and healthy subjects.
B J Morrison - One of the best experts on this subject based on the ideXlab platform.
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Ophthalmic artery Flow Velocity in glaucomatous and normal subjects.
The British journal of ophthalmology, 1993Co-Authors: P Rojanapongpun, S M Drance, B J MorrisonAbstract:The Velocity of blood Flow in the ophthalmic artery was measured with a transcranial Doppler ultrasound (2 MHz). Sixty patients with chronic open angle glaucoma (COAG), 42 patients with normal tension glaucoma (NTG), and 35 normals were studied. Peak Flow Velocity (peak), mean-enveloped Velocity (mean) and diastolic Velocity were compared in the three groups. The COAG patients and the NTG patients showed a significant reduction of all three Doppler Flow velocities compared with the normals (COAG vs normal, p = 0.013, 0.019, and 0.009; NTG vs normal, p = < 0.001, < 0.001, and < 0.001 for peak, mean and diastolic Flow Velocity respectively). The NTG patients also had a significant slower mean Flow Velocity than the COAG patients (p = 0.016), but not for peak and diastolic Flow velocities (p = 0.060 and 0.052 respectively). Based on ophthalmic Flow Velocity values, many NTG patients and a few COAG patients had slower Flow velocities than the normals. The significance of these haemodynamic differences is not yet known.
