Microcirculation flow alterations in burn wounds.
Explore the source record for details and available documents.
Adult↗
SEARCH · PubMed Health
Results for “Laser-Doppler Flowmetry”
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[Resistance index of anterior cerebral artery in the diagnosis of hypoxic ischemic encephalopathy in neonates].
OBJECTIVE: To study the relationship between the resistance index (RI) of the anterior cerebral artery and hypoxic ischemic encephapathy (HIE) in neonates for the purpose of finding out a method of diagnosing and predicting HIE and its prognosis. METHOD: The anterior cerebral artery blood flow velocity waveform (aCAFV) of neonates was recorded by a continuous Doppler technique and RI value was measured. 230 observations on 67 cases of high risk neonates and 534 on 182 normal neonates were performed. The mean value of RI and its standard deviation in normal neonates chosen served as control. The relationship between the standardized incidence of abnormal RI of the anterior cerebral artery and HIE was studied in high risk neonates. RESULT: In normal neonates (control group), RI was 0.62 +/- 0.09, and was in positive correlation (r = 0.72, P < 0.05) with the days after birth. The normal aCAFV was a regular waveform. In high risk neonates, the standardized incidence of abnormal RI in the neonates most likely to be attacked by HIE (A group) was significantly higher than that in control group (P < 0.001), but there was no significant difference between the other babies (B group) and control group (P > 0.05). However, the standardized incidence of abnormal RI in the A group was also significantly higher than that in the B group (P < 0.001). In the cases who were severely attacked by HIE, the standardized incidence of irregular waveform was the highest. Furthermore, when irregular aCAFV waveform appears, the incidence of pernicious complication of HIE and mortality of neonates were significantly increased in all cases. CONCLUSION: The abnormal RI value of anterior cerebral artery implies the existence of HIE in neonates. The prognosis is poor when irregular blood flow waveform appears.
Blood Flow Velocity↗
[An experimental study of blood supply to the bile duct under arterio-portal shunting].
The aim of this study is to show whether arterio-portal shunting (APS) improves the blood supply to the bile duct (BD) subsequent to clamping of the arterial blood supply to the liver and the BD. A constant flow APS model was undertaken using beagles. The procedure involved arterio-portal shunting by performing a bypass from the femoral artery to the portal vein (PV) following clamping, assisted by a roller-pump. In one group (Clamp group: n = 6) the shunt flow was kept at 0 ml/min/kg resulting in a reduction in the tissue oxygen saturation level of the BD (%BDISO2) to 28%, and a reduction in the tissue blood flow of the BD (%BDBF) to 17%, of the pre-clamped values. The %BDISO2 and %BDBF were measured by a Tissue-Spectrophotometer and Laser Doppler Flowmeter, respectively. The %BDISO2 and %BDBF decreased rapidly and thereafter were constant. In the other group (Shunt group: n = 6) the shunt flow was kept at 14 ml/min/kg. An increase in the %BDISO2 and %BDBF to 57% and 47%, respectively, was observed. A flow-controlled APS model was also carried out (n = 6). It was found that by periodically increasing the shunt flow from 0 to 7, 14, and 28 ml/min/kg, the %BDISO2, %BDBF, PVSO2 (PV oxygen saturation), and PVF (PV flow) all gradually increased. Statistically, positive correlations were found between the %BDISO2 and PVSO2 (p < 0.0001) and the %BDBF and PVF (p = 0.0002). Twenty additional beagles were divided into a Control group (n = 9) and an APS group (n = 11). In the Control group, a choledochojejunostomy was performed. In the APS group however, in addition to a choledochojejunostomy, one end of the hepatic artery was anastomosed to the side of the PV following ligation of the common hepatic artery, the gastro-duodenal artery and the right gastric artery. The survival ratio, concentration levels of serum total bile acid, total bilirubin, ALP, LAP, and gamma GTP, as well as, histological findings were not significantly different between the Control and the APS group. This study indicates that the blood supply is significantly improved by APS accompanied by clamping of the arterial blood supply to the liver and the BD. This procedure would therefore be useful in the preservation of the bile duct's viability and the bilioenteroanastomosis in clinical practice.
Anastomosis, Surgical↗
[The effect of degenerative cervical spine lesions and blood flow velocity in vertebrobasilar system in Doppler measurement].
The purpose of the study was to establish the effect of degenerative lesions of cervical vertebrae on blood flow velocity in the vertebrobasilar system measured by means of Doppler phenomenon using Transpect--TCD device according to generally accepted principles. The study was carried out in 20 healthy controls and 40 individuals with these lesions (aged 16-60 years). It was found that blood flow velocity in this arterial system is highly variable individually. In patients with degenerative changes pathological reduction of this velocity was found in this system which is an unquestionable evidence of the influence of these lesions on blood flow in vertebral arteries.
Adolescent↗
[Monitoring of the circulation in transferred skin-flaps].
Explore the source record for details and available documents.
Blood Gas Monitoring, Transcutaneous↗
Changes of motor evoked potentials in global and focal ischemic models of cats.
In order to evaluate the significance of motor evoked potentials (MEPs) in central nervous system monitoring, the authors conducted two sets of experiments using feline ischemic models. Twenty-three adult mongrel cats were divided into two groups: global (n = 9) and focal ischemic (n = 14) groups. In the case of global ischemia, which was induced by hypovolemic hypotension due to blood letting, deterioration of the D wave began when the mean arterial blood pressure (MABP) approached 45 mmHg, and regional cerebral blood flow (rCBF) dropped to 40% of control. Complete disappearance of the D wave was observed below 30 mmHg in MABP and 20% of control in rCBF. In the case of focal ischemia, which was induced by transorbital occlusion of the middle cerebral artery, the percentages of rCBF at which the D wave disappeared ranged from 9 to 20%. Changes in the amplitude of the D wave--an increase and following decrease--preceded the prolongation of its latency. In contrast with the D wave I waves were too easily affected by ischemia. Moreover, rCBF at the point of disappearance of the I wave varied greatly. In conclusion, the D wave is stable in mild ischemia and is a reliable indicator of critically profound ischemia (%rCBF < 40%). Monitoring the D wave of MEPs seems to be a useful method for avoiding the deterioration of motor function by ischemic insult.
Animals↗
[Effects of buflomedil and naftidrofuryl on the human cochlear microcirculation measured by laser-Doppler].
The aim of this study was to assess the effects on cochlear blood flow measured by laser-Doppler of two vasoactive agents known for their supposed effectiveness in the presbyacousy treatment (buflomedil, naftidrofuryl), 16 patients undergoing acoustic neurinoma surgery were studied. Cochlear blood flow (CBF) was continuously recorded after the head of the probe was inserted into the internal ear through the round window. Systolic arterial pressure (SAP) and heart rate (HR) were continuously recorded via an arterial cannula. Hemodynamic variations due to buflomedil (400 mg in bolus) and to naftidrofuryl (200 mg in bolus) were compared with those of sodium nitroprusside (500 micrograms in bolus) in each case with anova. Buflomedil did not alter CBF (0%), SAP (+0.14 +/- 1.7%), HR (+3.4 +/- 3.4%). Naftidrofuryl provoked a significant decrease (P < 0.05) of CBF (-14.5 +/- 7.55%), SAP (-13.7 +/- 4%), and a significant increase (P < 0.05) of HR (+8.5 +/- 3.5%); there is a relationship between CBF and SAP (r = 0.88 P < 0.05). NPS provoked a significant decrease (P < 0.01) of CBF (-34.7 +/- 7.7%) SAP (-26.8 +/- 5.4%) and a significant increase (P < 0.01) of HR(+14.7 +/- 7.3%) in the same way of naftidrofuryl (P < 0.01). In conclusion, human cochlear microcirculation depends upon pharmacological hemodynamic variations such as animal models or middle ear microcirculation. If buflomedil did not alter it, naftidrofuryl provoked a reduction by a direct vasodilator effect inducing hypotension like sodium nitroprusside.
Cochlea↗
Portal hypertensive gastropathy and gastric mucosal blood flow.
Explore the source record for details and available documents.
Blood Flow Velocity↗
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↗
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↗
[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↗
[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↗
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↗
[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↗
[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↗
[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↗
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↗
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↗