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Results for “Laser-Doppler Flowmetry”

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At least 523 records · Page 29Linked to original sources
PubMed1995

Comparison of gastric mucosal blood flow in normal subjects and in patients with portal hypertension using endoscopic laser-Doppler velocimetry.

OBJECTIVE: To compare gastric mucosal blood flow (GMBF) in normal subjects with that in patients with portal hypertension with or without portal hypertensive gastropathy (PHG). METHODS: GMBF was measured by endoscopic laser-Doppler velocimetry in 20 gastroscopically normal subjects and 30 patients with portal hypertension with or without PHG. The effects of breath-holding (vasomotor reflex), submucosal epinephrine and sublingual isosorbide dinitrate were also studied. RESULTS: In normal subjects, GMBF on the greater curvature was (mean +/- SD) 9.5 +/- 1.3 V and on the lesser curvature, 9.1 +/- 1.9 V. Breath-holding caused a reduction in GMBF by 57.1 +/- 13.7%, submucosal epinephrine reduced it by 41.5 +/- 21.5% and sublingual isosorbide caused a rise of 25.8 +/- 15.2%. The GMBF on the greater and lesser curvature respectively in patients with mild PHG (7.7 +/- 1.2 V and 7.7 +/- 0.8 V) and those with severe PHG (6.5 +/- 3.5 V and 6.3 +/- 2.2 V), was significantly less than that in normal subjects (p < 0.05 and p < 0.001 respectively). Vasomotor reflex was blunted in patients with mild and severe PHG (23.3% +/- 20.3 and 23.1% +/- 17.7 respectively, p < 0.001). Responses to submucosal epinephrine and sublingual isosorbide were similar to those recorded in normal subjects. CONCLUSIONS: Patients with portal hypertension have significantly reduced GMBF and significantly attenuated vasomotor reflex in the gastric vascular bed as compared to normal subjects.

Adult↗
PubMed1995

Simultaneous laser Doppler and transcutaneous oxygen tension measurements in claudicant patients.

Laser Doppler (LD) flux and transcutaneous oxygen tension (TcPO2) were measured in supine and sitting position at the dorsum of the foot with local skin temperature of 37 degrees C and 44 degrees C in 50 patients with stage IIb of chronic peripheral arterial occlusive disease (CPAOD) and in 30 healthy controls. The statistical analysis showed no significant differences between patients and controls in the supine and sitting position at 37 degrees C. A lower increase of LD- flux and TcPO2 could be noticed during hyperthermia and reactive hyperaemia in the patients group as well as a significant prolongation of oxygen (ORT) and flux reappearance time, of postocclusion time to peak flux and oxygen peak, of postocclusion time to half of peak flux and oxygen peak and of time to flux restoration at preocclusion levels (FTMAX) during reactive hyperaemia test. FTMAX and ORT allowed a clear separation between patients and controls and exhibited a high reproducibility. A regression analysis equation was derived with the most significant parameters indicating the presence and the severity of the disease. Moreover, the estimated time parameters of LD - flux and TcPO2 were correlated with the US - Doppler ankle systolic blood pressure indices and therefore with the impairment of the macrocirculation. In summary, we find that skin perfusion in patients with intermittent claudication is not different from normal subjects under basal conditions. However, maximal perfusion is reduced and the time to peak perfusion after a provocative stimulus is delayed.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Gas Monitoring, Transcutaneous↗
PubMed1995

[Color-coded duplex ultrasound and laser Doppler flowmetry of finger tips of healthy probands].

In the study presented, color-coded duplex sonography (CCDS) and laser Doppler flux (LDF) signals from finger tips of 7 healthy individuals were recorded simultaneously. The aim of the study was to examine whether or not the results of a functional test ('deep inspiration') could also be observed with an ultrasonic Doppler. In the literature this test is known to provoke notable blood flow characteristics of the LDF ('inspiratory gasp'), a phenomenon which is caused by a sympathetically mediated vasoconstriction of acral vessels. With regard to the penetration depth of the LDF in skin it was of further interest to determine the distance between the surface of the skin and the vessels found near the surface. We found for CCDS parameters (color pixels/image; time-averaged flow velocity [TAV]; resistance index [RI]) as well as for LDF (flux [taLDF]) significant changes before versus after 'deep inspiration'. CCDS is a new diagnostic tool to visualize also very small vessels down to 0.2 mm, e.g. in finger tips. It should be evaluated which role this method may play in combination with functional tests in diagnostic handling, e.g. of patients with polyneuropathies or collagenoses.

Adolescent↗
PubMed1995

[Diagnostic imaging of microcirculation of pedicled flap-plasties of the mandibulofacial area using the laser Doppler scanner].

Objective, non-invasive examination techniques in addition to clinical parameters are required to monitor the wound healing of flaps. With the new Laser-Doppler Scanner (LDI, PIM 1.0 Lisca Development AB, Sweden) it is possible to measure and visualize microcirculation continuously, non-invasively and without contact to the wound in an area of 12 x 12 cm. We performed measurements and simultaneous two-dimensional imaging of microcirculation 24, 48, 72 hours and five and 14 days postoperatively in 22 patients, who received reconstruction procedures with random or axial pattern flaps. The perfusion diagrams were correlated to the clinical aspect. Necrotic areas, venous stasis, and normal course of wound healing can be clearly visualized and differentiated. The new Laser-Doppler Imaging System (LDI) serves as an excellent aid for control and planning of flaps in plastic and reconstructive surgery.

Adolescent↗
PubMed1995

The Pringle maneuver induces only partial ischemia of the liver.

It has been questioned whether the Pringle maneuver induces complete ischemia of the liver. We examined changes in liver blood flow (LBF) in sixty patients who underwent liver resection, under conditions of prolonged inflow occlusion. The ischemia period ranged from 30 to 75 minutes. All patients tolerated the procedure. To better understand the metabolic consequences of ischemia, 10 female mongrel pigs were divided into two groups treated with hepatic inflow occlusion or total vascular exclusion for one hour (n = 5, each). Clinical and experimental data showed approximately 10% of residual LBF under the Pringle maneuver. Only one out of five animals tolerated complete ischemia (total vascular exclusion) in terms of 7-day survival while all pigs treated with the Pringle method survived. This was attributed to the lower serum transaminase levels and attenuation of liver adenosine triphosphate (ATP) decline in the inflow-occluded group. Our data indicate that the Pringle maneuver induces partial rather than full ischemia of the liver and hepatic vein "back flow" is likely to be the cause. The clinical implications of hepatic inflow occlusion for liver surgery are discussed.

Adenosine Triphosphate↗
PubMed1995

[Dynamic function tests for detection of physiologic and pathophysiologic reactions in cutaneous microcirculation].

Functional tests simulating local stresses are especially suitable for the evaluation of physiological and pathophysiological patterns in the cutaneous microcirculation, particularly if combined with non-invasive methods such as laser-Doppler fluxmetry and oxygen tension measurements. Arterial occlusion (3 min) and local heating (up to 42 degrees C) are appropriate as stimuli to simulate specific local demands on the cutaneous perfusion similar to those produced by pressure, myokinesis, heat, and inflammation. When the current microcirculatory status is described the initial values (LDF and pO2) and their time-courses during each functional test can be used to determine the so-called post-stimulatory parameters. These-- corresponding to physiological equivalents--allow statements on the vascular reactivity towards hypoxia and ischaemia. Furthermore, dynamic performance parameters can easily be derived from the poststimulatory values. They describe the capacity of cutaneous microcirculation with regard to perfusion reserves and ischaemic tolerance in local stress situations in an appropriate manner. As an example of the usefulness of functional tests for cutaneous microcirculation, the physiological and pathophysiological patterns found in systemic sclerosis are described.

Blood Flow Velocity↗
PubMed1993

[Substance P in plasma of patients with allergic rhinitis and its clinical significance].

By using the supersensitive and highly specific SP-radioimmunoassays to measure the concentration of substance P (SP) in the plasma of patients with allergic rhinitis, the authors found that the levels of SP in the plasma had significantly increased as compared with normal controls (P < 0.001). Using the laser-Doppler flowmeter to measure the blood flow in the nasal mucosa, it was also found that the increase in blood flow in the nasal mucosa had a close correlation with the content of SP. The results show that SP could induce vasodilation in nasal mucosa, lead to a significant increase in nasal blood flow. The pathogenetic importance of the neuropeptide SP in allergic rhinitis and the clinical significance of changes in SP in the plasma of subjects with allergic rhinitis has been discussed.

Adolescent↗
PubMedDate not supplied

[Doppler laser interferometry in the determination of ultrafiltrate consumption].

To evaluate the clinical efficiency of hemodialysis and ultrafiltration monitoring, the consumption and volume of an ultrafiltrate should be timely measured. Balance measurement of changes in a patient's body weight during hemodialysis has a significant methodological error made by patient's body weight changes unassociated with ultrafiltration.

Hemofiltration↗
PubMedDate not supplied

[Ovarian varicocele: percutaneous treatment. A preliminary note].

Incontinence of ovarian veins and development of adnexal varicosities (pelvic varicocele) seems to cause pelvic pain syndrome in about 50% of the cases. Whereas the diagnosis of male varicocele is usually clinical, the same diagnosis in a woman needs instrumental methods; therefore the number of diagnosed cases is lower than the real incidence of the disease. In the last 18 months 2 patients with ovarian varicocele and chronic pelvic pain have been successfully treated by percutaneous sclerotization of the gonadal veins with resolution of the pelvic pain syndrome. We preferred this interventional procedure to the surgical one, as is usually the case with male varicocele, where percutaneous therapy is considered the treatment of choice on the basis of long-term results, since its first attempt in 1977. Considering the effectiveness of this simple and non-surgical therapy for chronic pelvic pain, we stress the importance of correct and early diagnosis of pelvic varicocele.

Adult↗
PubMedDate not supplied

[Retrospective analysis of color Doppler ultrasonography and flowmetry findings in solid nodular pathology of the breast].

The authors tried to identify useful flowmetric values and color-Doppler patterns for the differential diagnosis between benign and malignant solid breast lesions. To this purpose, 106 patients with breast nodules detected at mammography and/or high resolution US were examined. A US scanner with a linear 7.5 MHz transducer, a narrow sample volume, a PRF ranging (650-800 Hz) and a wall filter value of 50 Hz were used. Three parameters were considered: the number vascular sites, systolic peak velocity and pulsatility index. All these parameters related to tumor volume. Several (> 2) vascular sites, high peak velocity and quite high pulsatility index were demonstrated in malignant tumors (46 lesions). Among benign tumors no vascular site was identified in 32 of 60 lesions and no more than 2 sites were identified in 26 of 60 lesions, except for 2 phylloides tumors. Sensitivity, specificity, positive and negative predictive values and overall accuracy rates were, as for the "vascular sites" parameter, 78%, 96%, 94%, 85%, 88%, respectively; as regards the "peak systolic velocity" 81%, 86%, 89%, 75%, 83% respectively; as regards the "pulsatility index" 100%, 85%, 100%, 85%, 94% respectively.

Adult↗
PubMed1995

Doppler velocimetry and fetal heart rate pattern observations in acute cocaine intoxication. A case report.

While the use of cocaine in pregnancy continues to be a significant contributor to adverse maternal and perinatal outcomes, systematic study of the physiologic effects of cocaine in human gestation remains difficult. In a case of acute cocaine intoxication in the third trimester, Doppler velocimetry suggested a physiologic response from the uterine artery but not the umbilical artery. Furthermore, the abnormal uterine artery velocimetry was associated with a positive nonreactive contraction stress test, which became negative and reactive as the effects of the cocaine wore off and the velocimetry returned to normal. These observations suggest that the uterine arteries are more sensitive to cocaine than are the umbilical arteries and that abnormal fetal heart rate patterns during acute cocaine intoxication may be transitory.

Adult↗
PubMedDate not supplied

[Use of laser doppler flowmeter for the early diagnosis of diabetic microangiopathies].

Use of laser doppler flowmeter helped reveal in patients with diabetes mellitus a decrease of volumetric bloodstream in the capillaries of skin in the absence of clinical and biochemical evidence of microcirculatory disorders. Bloodstream parameters were correlated to the findings of objective methods of diagnosis at the stage of manifest clinical signs of vascular involvement of various localizations. Laser doppler flowmeter may be used for preclinical diagnosis of renal and ophthalmic involvement in diabetics with types I and II conditions as a method to monitor the therapy efficacy in patients with apparent clinical signs of microangiopathies. We should like to emphasize the possibility of mass screenings of patients and the simple technique of using the device, as well as the possibility of assessing the bloodstream not only in the skin, but in the organs and retina as well.

Adolescent↗
PubMed1994

[Laser Doppler flowmetry for evaluation of nasal mucosa microcirculation].

The purpose of this study was to determine the blood flow within the human nasal mucose and whether it is changed in patients with chronic rhinitis. Using a laser Doppler flowmeter (He-Ne Laser equipment PF2 type), we measured the nasal mucosa blood flow (NMBF) in a group of healthy young subjects 108 (18-25 years) and three types of chronic rhinitis 89 (chronic rhinitis 15, allergic rhinitis 44, atrophic rhinitis 30). A Laser Doppler probe was placed on six different points of the nasal mucose membrane. The study data indicate that the average index of the NMBF of human are retentive steady and decreased obviously in three types chronic rhinitis. So it may be concluded that detection of NMBF is a useful method for evaluation of the therapy effect of chronic rhinitis.

Adolescent↗
PubMed1995

[Improvement of highly reproducible technique of four-vessel occlusion model and its study on metabolic changes of cerebral reperfusion in rats].

The four-vessel occlusion method introduced by Pulsinelli et al is widely used as an experimental model for reversible forebrain ischemia in rats. However, this model has a major problem in the difficulty assuring complete occlusion of the vertebral arteries by electrocauterization through the alar foramina of the first cervical vertebra. Anatomical basis of the vertebral artery suggested by Sugio et al indicates that the vertebral artery at the level of the second cervical vertebral is visible. In this study, we further developed highly reproducible model of reversible forebrain ischemia, which is modified four-vessel occlusion in rats. Male Wistar rats were subjected to four-vessel occlusion. Under microscope the visible vertebral arteries at the second vertebra could be easily electrocauterized and completely cut by microscissors to yield complete cessation of circulation of bilateral vertebral arteries without failure. After 24 hours, animals were subjected to 15, 30 and 45 minutes of forebrain ischemia by occluding both common carotid arteries with Sugita's temporary clips. 31P-magnetic resonance spectroscopy (31P-MRS) were obtained with a 6.3-T spectrometer to investigate sequential change of the in vivo brain energy metabolism. Our studies indicated that high energy phosphorus compounds were reduced in a few minutes after the induction of the forebrain ischemia, and they returned to the normal level after the recirculation. In addition, we monitored electroencephalogram (EEG) during the whole experimental period. The EEG showed a flat pattern after the induction of ischemia, and EEG recovered normal pattern within 12 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Microcirculatory changes in mitral prolapse as an expression of a systemic change in the connective tissue].

Many authors hypothesize that mitral valve prolapse (MVP) can be, in most cases, only a clinical sign of a primitive and systemic disorder of the connective tissue, like in Marfan Syndrome (MS). In our previous works we supported the presence of morphological and functional alterations of the microcirculation in patients affected by MS. In order to characterize a possible common denominator between these pathologies we have studied the cutaneous microcirculation in a group of patients affected by MVP, divided into 2 groups: anatomic MVP (MVP) and MVP syndrome (MVPS). The morphologic parameters have been investigated by nailfold capillaroscopy while digital laser-Doppler was used to study skin flowmetry. The results have been compared with a control group. Capillaroscopic remarkers showed an architecturally disorganized microvasculature with aspects related to a reduced compactness of the microvasculature unit with a significatively higher score compared with controls (7.3 +/- 2.9 vs 3.6 +/- 1 p less than 0.0005). Laser-Doppler flowmetry showed a significatively reduced rest flow; ischemic test showed: spike time 48.9 +/- 36.9 vs 15.3 +/- 7.7 s (p less than 0.0005), hyperemic acme 6.6 +/- 2.7 vs 12.5 +/- 8.4 UP (p less than 0.002); % increase 32.1 +/- 20.2 vs 51.5 +/- 15.4 (p less than 0.002). Thermic test showed a significatively higher thermic acme 8.7 +/- 4.2 vs 12.6 +/- 9.11 UP (p less than 0.05). These results appeared to be correlated with stage pathology as it was observed a severe microvasculature disorders in MVPS. Therefore we suppose that a phenotypic continuum may exist between MS and MVP.

Adult↗
PubMed1982

Current status of noninvasive tests in the diagnosis of peripheral arterial disease.

In this review of the current status of the vascular laboratory, the major emphasis has been upon those tests that have become well-established and documented, including resting pressure, pulse volume measurements, velocity studies, and three stress measurements--exercise ankle pressure, postocclusive reactive hyperemia, and the toe pulse reappearance time. Additional technology that may have application to peripheral arterial disease includes photoplethysmography, transcutaneous oxygen tension, laser-Doppler velocimetry, fluorescein angiography, infrared thermography, and transcutaneous electromagnetic flowmetry. These techniques, which are currently in development and experimental trial, were not discussed but are likely to provide significant additional information. The future role of the vascular diagnostic laboratory in the area of peripheral arterial occlusive disease appears clear. It has already become a standard resource of the community hospital and tertiary referral center. Its functions will become more and more generally accepted with time as newly graduating physicians who have been exposed to this technology enter the practice of medicine. It should permit obtaining an evaluation of all patients at the expert level, aid in the education of all physicians concerned with peripheral arterial disease, and play an important part in guaranteeing a higher level of patient care than has heretofore been available.

Arterial Occlusive Diseases↗
PubMed1988

Partitional measurement of capillary and arteriovenous anastomotic blood flow in the human finger by laser-Doppler-flowmeter.

This study was made to see whether changes in blood flow through the capillaries and arteriovenous anastomoses (AVA's) of the human finger can be measured by noninvasive flowmetry. Total finger blood flow (FBF) was measured by venous occlusion plethysmography; blood flow was measured by a laser-Doppler flowmeter (ADVANCE, ALF-2100, Tokyo, Japan) using probes with optic fiber separations of 0.3 mm (LDF-0.3) and 0.7 mm (LDF-0.7). The maximum sensitivities for LDF-0.3 and LDF-0.7 were at depths of 0.8 and 1.2 mm from the tissue surface respectively. Two series of experiments were performed on separate days. In the first series the test hand was immersed in a water bath whose temperature (Tw) was 25 degrees C at an ambient temperature (Ta) of 25 degrees C. Tw was raised to 35 degrees C (local hand warming), which was then followed by an increase in Ta to 35 degrees C (whole body warming). FBF, LDF-0.3, and LDF-0.7 increased during these thermal stimulations. However, the relationship of FBF to LDF-0.3 showed two different regression lines. In contrast, the relationship of FBF to LDF-0.7 showed a single regression line. In the second series, with Ta at 35 degrees C, the test hand was immersed in a water bath at Tw 35 degrees C. Tw was then raised every 10 min by 2 degrees C steps from 35 to 41 degrees C. At Tw 39-41 degrees C, FBF and LDF-0.7 in the test hand were significantly decreased compared with those at Tw 35 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗