Dipartimento di Discipline Medico-Chirurgiche, Sezione di Anestesiologia e Rianimazione, Ospedale S. Giovanni Battista, Università di Torino, Corso Dogliotti 14, 10126, Torino, Italy. email@example.com
To examine the accuracy of transcranial Doppler to detect cerebral vasospasm in a patient population with aneurysmal subarachnoid hemorrhage.
Prospective blind comparison of transcranial Doppler with cerebral angiography. Diagnostic accuracy of transcranial Doppler was assessed using receiver operating characteristic (ROC) analysis and likelihood ratios. Sensitivity and specificity were calculated using directly measured middle cerebral artery diameter as reference standard.
Intensive Care Unit of a large university teaching hospital.
Twenty-two patients with subarachnoid hemorrhage were included. Patients underwent angiography on admission and after 8 days to diagnose vasospasm and were defined as having clinical vasospasm, angiographic vasospasm, or no vasospasm.
Sensitivity and specificity were 1.00 and 0.75 for angiographic vasospasm and both equal to 1.00 for clinical vasospasm diagnosis. A transcranial Doppler mean velocity threshold value of 100 cm/s for angiographic vasospasm and 160 cm/s for clinical vasospasm detection were chosen by ROC analysis.
A Transcranial Doppler mean velocity threshold of 160 cm/s, calculated by the ROC analysis, accurately detects clinical vasospasm. A daily transcranial Doppler examination performed by a trained operator should be routinely used to provide early identification of patients at high risk and to orient therapeutic decisions.
22 healthy subjects aged from 25 to 45, mean age 32.7+/-5.3, have been observed. Every patient was subjected to diagnosing cerebral hemodynamics carried out every 7 days during 6 weeks. The circulation of common carotid artery, middle cerebral arteries and internal jugular arteries has been studied by means of LOGIQ-500MD (GE MS, USA) apparatus. The determination of arterio-venouse balance of cerebral hemodynamics was shown to be worthwhile for common carotid artery and its homolateral internal jugular artery. Arterio-venouse balance is presented as a ratio of circulation blood velocity in common carotid and internal jugular arteries.
We assessed the convergent validity of commonly applied metrics of cerebral autoregulation (CA) to determine the extent to which the metrics can be used interchangeably. To examine between-subject relationships among low-frequency (LF; 0.07-0.2 Hz) and very-low-frequency (VLF; 0.02-0.07 Hz) transfer function coherence, phase, gain, and normalized gain, we performed retrospective transfer function analysis on spontaneous blood pressure and middle cerebral artery blood velocity recordings from 105 individuals. We characterized the relationships (n = 29) among spontaneous transfer function metrics and the rate of regulation index and autoregulatory index derived from bilateral thigh-cuff deflation tests. In addition, we analyzed data from subjects (n = 29) who underwent a repeated squat-to-stand protocol to determine the relationships between transfer function metrics during forced blood pressure fluctuations. Finally, data from subjects (n = 16) who underwent step changes in end-tidal P(CO2) (P(ET)(CO2) were analyzed to determine whether transfer function metrics could reliably track the modulation of CA within individuals. CA metrics were generally unrelated or showed only weak to moderate correlations. Changes in P(ET)(CO2) were positively related to coherence [LF: ß = 0.0065 arbitrary units (AU)/mmHg and VLF: ß = 0.011 AU/mmHg, both P
The risk of stroke related to asymptomatic carotid artery stenosis is known to be increased in high-grade or rapidly progressive stenosis. Information of the prevalence in the general population is required for the recommendation of screening methods to detect patients needing prophylactic treatment. We studied the prevalence and the grade of severity of extracranial carotid and vertebral artery obstructions by means of Doppler sonography in 529 asymptomatic Russians (m: 343, f: 186; 36-84 years, mean: 58.4 years) living in Moscow city. Internal carotid artery obstructions of more than 50% stenosis were present in 22 (= 4.2%) subjects, 8 of them (1.5%) had bilateral lesions. Appropriate abnormal findings in vertebral arteries were found in 11 (= 2.1%) subjects, in 1 of them bilaterally. Affection of both the carotid and the vertebral arteries was noted in 4(= 0.8%) individuals. There were no sexual differences. The risk factor which correlated most significantly with cervical arterial lesions was hypertension. Carotid lesions were also significantly associated with age and smoking, but not with diabetes or hyperlipoproteinemia. The prevalence of cervical artery stenoses was found to be lower than in western reports, which may be due to different technical equipment and different study design.
The article presents the results of Doppler examination of 44 healthy children and 180 children with chronic pathology of alimentary tract. All the patients underwent the reactivity test of the middle cerebral artery after graduated cool-water bearing. Dynamics of the studied data are presented in the article. The obtained results indicate more distinct changes of function of the vegetative nervous system in children with organic pathology of the alimentary canal.
We have compared the effectiveness, time required for de-airing, and safety of a newly developed de-airing technique for open left heart surgery (Lund technique) with a standardized carbon dioxide insufflation technique.
Twenty patients undergoing elective open aortic valve surgery were randomized prospectively to the Lund technique (Lund group, n = 10) or the carbon dioxide insufflation technique (carbon dioxide group, n = 10). Both groups were monitored intraoperatively during de-airing and for 10 minutes after weaning from cardiopulmonary bypass by transesophageal echocardiography and online transcranial Doppler for the severity and the number of gas emboli, respectively. The systemic arterial partial pressure of carbon dioxide and pH were also monitored in both groups before, during, and after cardiopulmonary bypass.
The severity of gas emboli observed on transesophageal echocardiography and the number of microembolic signals recorded by transcranial Doppler were significantly lower in the Lund group during the de-airing procedure (P = .00634) and in the first 10 minutes after weaning from cardiopulmonary bypass (P = .000377). Furthermore, the de-airing time was significantly shorter in the Lund group (9 vs 15 minutes, P = .001). The arterial pH during the cooling phase of cardiopulmonary bypass was significantly lower in the carbon dioxide group (P = .00351), corresponding to significantly higher arterial partial pressure of carbon dioxide (P = .005196) despite significantly higher gas flows (P = .0398) in the oxygenator throughout the entire period of cardiopulmonary bypass.
The Lund de-airing technique is safer, simpler, and more effective compared with the carbon dioxide insufflation technique. The technique is also more cost-effective because the de-airing time is shorter and no extra expenses are incurred.
Transcranial Doppler sonography and impedansometry was used to study cerebral circulation in students aged from 7 to 17 living in the North in the "absolute discomfort" area (Magadan region. 62 degrees North, 158 degrees East, n = 167) and "discomfort" area (Arkhangelsk region, 61 degrees North, 41 degrees East, n = 52). New data were obtained about both blood flow parameters in main cerebral arteries, vessels tone and vasomotor reactivity as well as differences between these indices in children from the two northern areas. The results reveal that arterial blood flow velocity (BFV) in cerebral arteries is faster in Koryaks and Evens who are the children of the native population compared to BFV in the children born in the North whose parents represent newcomers. A tendency exists in the form of vascular tone rising in the living in the North students. This tendency is more expressed in children and adolescents from Magadan region which is distinguished from Arkhangelsk region by more severe climate. The indices that characterize individual alterations of cerebral circulation under hypoxic-cold factors as well as population peculiarities related to "polar adaptive type of metabolism" forming are discussed.
Transcranial Doppler (TCD) has been subjected to criticism for detecting vasospasm (VSP). Our study's aim is to derive criteria for middle cerebral artery (MCA) vasospasm (MCA-VSP) based on cerebral angiography (CA).
A prospective data of patients with aneurysmal subarachnoid hemorrhage (aSAH) from January 2004 to August 2009. TCD was performed daily from day 2 to 14 from symptom's onset. Follow-up CA was done at day 7-9. TCD mean flow velocities (MFV) of all vessels at baseline (b), middle (m) and before CA (preangio) were recorded. Several MCA MFV ratios were computed. Moderate to severe VSP on CA was defined as >1/3 luminal narrowing. Univariate and stepwise logistic regression analysis were performed.
One hundred sixty-nine patients (338 MCA) with aSAH were included, mean age: 54.8 ? 13, women: 103 (62%). Twenty-nine patients (8.6%) had angiographic MCA-VSP. TCD scoring system of 3 points for MCA-VSP was computed based on (a) bMCA MFV = 120 cm/s (sensitivity: 59.3%, specificity: 85%, PPV: 36.4%, NPV: 93.5%, P
The author studied features of indices of the central, cerebral haemodynamics and penetrability of cellular membranes in patients with hypertensive disease during the treatment of the disease through oral and transdermal formulation of riodipin. It was established that efficiency of the treatment increases when transdermal formulation of riodipin was used.
Duplex ultrasound (DUS) has shown a >90% accuracy compared to angiography, concerning the degree of internal carotid artery (ICA) stenosis. However, uncertainty may occur in a severe stenosis, in which peak systolic velocity (PSV) may decrease owing to high flow resistance or high backward pressure. We investigated intracranial collateral flows using transcranial Doppler (TCD) to further evaluate the hemodynamic significance of high-grade ICA stenosis.
In this retrospective study, 320 consecutive symptomatic patients were examined. The degree of ICA stenosis and collateral capacity in the circle of Willis was investigated by DUS and TCD. In addition, magnetic resonance angiography (MRA) was added in a subgroup of 204 patients. The criterion for hemodynamic significant ICA stenosis was established collateral flow.
In 91% of all symptomatic vessels (291 vessels), an ICA stenosis of =70% was found. Established collateral flow always indicated precerebral carotid artery disease of =70%. Furthermore, in 11% of the whole study material, collateral reserve capacity was found despite high-grade (=70%) ICA stenosis. PSV in ICA
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