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Results for “Laser-Doppler Flowmetry”

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At least 559 records · Page 31Linked to original sources
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↗
PubMed1995

Use of a low profile Doppler angioplasty guidewire to evaluate the effect of percutaneous coronary angioplasty on coronary artery flow velocity.

BACKGROUND: The intracoronary Doppler flow velocity measurement is widely used. The Doppler flow catheter, used in many studies, still cannot always measure distal portions of coronary artery stenosis. However, three years ago, a low profile Doppler angioplasty guide wire (0.018-inch) was started by apply for measurement of changes in proximal and distal flow velocity during coronary angioplasty. METHODS: Blood flow velocity and diastolic/systolic velocity ratio (DSVR) on both proximal and distal portions of the coronary artery were measured with a low profile Doppler angioplasty guide wire in 13 patients with stenosis of the left anterior descending artery (LAD) during coronary angioplasty. RESULTS: Non-significant improvement in maximal peak velocity was noted in the distal portion of the coronary artery immediately after angioplasty (before, 36 +/- 12 cm/s; after, 41 +/- 12 cm/s; p > 0.05); but significant improvement was found after removal of the balloon (from 41 +/- 12 cm/s to 49.5 +/- 15 cm/s, p < 0.01). Increases in proximal maximal peak velocity after angioplasty were less remarkable (before, 38.5 +/- 15 cm/s; after, 45 +/- 13 cm/s; p > 0.05), and there was a significant increase of DSVR on the distal portion of the left anterior descending artery after angioplasty (before, 2.18 +/- 0.51; after, 2.98 +/- 0.44; p < 0.05). However, there was no significant increase of DSVR on the proximal portion of LAD (before, 2.19 +/- 0.16; after, 2.44 +/- 0.1; p > 0.05). The coronary flow reserve ratio showed no significant increase on the distal portion of the LAD (before, 1.03 +/- 0.3; after, 1.02 +/- 0.3) and proximal portion of LAD (before, 1.05 +/- 0.2; after, 1.03 +/- 0.3). CONCLUSIONS: Increase in peak velocity and DSVR of the distal portion of the coronary artery after angioplasty was more significant after removal of the balloon catheter than as if it were assessed immediately, without removing the balloon catheter. No significant increase in flow velocity of the proximal portion of the coronary artery after angioplasty was observed. No significant increase of the coronary flow reserve of the distal and proximal portion of the coronary artery occurred after successful angioplasty.

Adult↗
PubMed1994

[Evaluation of the influence of placental localization on qualitative estimation of waveforms of blood flow velocity in uterine and arcuate arteries in third trimester physiologic pregnancy].

We presented in our study methods and results of blood flow measurements with Doppler ultrasound in uterine and arcuate arteries in relation to localization of placenta in physiological pregnancy. We performed examinations in 154 pregnant women with pregnancy age of 32-42 wk. On the basis of qualitative analysis of blood flow waveforms we discovered the difference in the blood flow in utero-placental compartment in relation to placental localization and we proved that this change takes place in uterine as well an in arcuate arteries.

Adult↗
PubMed1995

Ischemic conditioning of the rat stomach: implications for esophageal replacement with stomach.

BACKGROUND: Esophagectomy, with gastric pull up replacement, is not uncommonly complicated by leakage from the esophagogastrostomy anastomosis. Occult ischemia of the mobilized gastric fundus is a major etiologic factor in anastomotic leakage. OBJECTIVE: To test the hypothesis that tissue perfusion in a partially devascularized stomach will improve over time by a process of ischemic conditioning ("delay" phenomenon). EXPERIMENTAL DESIGN COLON: Laboratory study of partial gastric devascularization in rats. ANIMALS: Twenty rats. INTERVENTIONS: Partial gastric devascularization was achieved by ligation of the left gastric artery. MEASURES: Gastric perfusion was measured with a laser-Doppler flowmeter (in tissue perfusion units, TPU). Perfusion measurements were made at baseline, after vessel ligation, at 7 days, and at 14 days. RESULTS: Perfusion immediately after vessel ligation (23.8 +/- 6.0 TPU) was significantly lower than baseline gastric tissue perfusion (88.4 +/- 9.8 TPU) (p < 0.00001). After 7 days, tissue perfusion had increased (54.4 +/- 9.2 TPU), but it was significantly lower than baseline values (p < 0.00005). After 14 days, perfusion was increased (71.7 +/- 8.6 TPU) compared to 7 day measurements (p < 0.001), but it was still significantly lower than baseline gastric tissue perfusion (p < 0.002). Nevertheless, 14 day perfusion was 81% of baseline values. CONCLUSIONS: After partial devascularization, gastric perfusion steadily improves by a process of ischemic conditioning ("delay" phenomenon). The principle of ischemic conditioning may be clinically applicable to the gastric pull up operation.

Animals↗
PubMed1994

Effects of hypnotic suggestions on ultraviolet B radiation-induced erythema and skin blood flow.

Results from both animal and human studies have indicated that inflammatory skin reactions such as the flare response to histamine prick test involve a neurogenic regulatory component. It is still unknown to which degree inflammation induced by ultraviolet (UV) radiation may be mediated by the central nervous system. To investigate this, the effect of hypnotic suggestions to increase and decrease the response to UVB radiation on erythema and cutaneous blood flow was investigated in 10 highly hypnotizable subjects. The results showed a significant effect of hypnotic suggestions on cutaneous blood flow compared with the responses of a control group. For erythema no conclusive evidence was found. The results indicate the possibility of separate regulatory mechanisms behind central nervous system influence on UVB-induced erythema and skin blood flow respectively, and further investigations are needed.

Adult↗
PubMed1994

[Respiration-dependence of cutaneous laser Doppler flow motion].

The aim of this study was to show and to quantify the breath-dependency of cutaneous fluxmotion in the volar proximal forearm using a new computer-aided system. A meanflux-related index (MI) representing the intensity of the influence of respiration on fluxmotion was calculated. There was a good correlation between MI and the rate of respiration under spontaneous breathing: the lower the rate of respiration, the higher the value of MI. Prescribing a constant breathing rhythm amplifies this frequency-dependent effect. According to occurrence of low rates of respiration (< 12/min) also under physiological conditions the respiration should be simultaneously recorded while assessing fluxmotion.

Adolescent↗