scholarly journals Experimental and Clinical Evaluation of Capsular and Parenchymal Total Liver Perfusion

HPB Surgery ◽  
1992 ◽  
Vol 6 (2) ◽  
pp. 99-104 ◽  
Author(s):  
Katerina Kotzampassi ◽  
Efthimios Eleftheriadis ◽  
Homeros Aletras
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Liver Perfusion ◽  
Liver Blood Flow ◽  
Laser Doppler ◽  
Biliary Surgery ◽  
Flow Measurements ◽  
Doppler Flowmetry ◽  
Total Liver ◽  
Liver Surface

Liver blood flow measurements obtained from both the liver surface and deep within the parenchyma, were correlated in an effort to assess the usefulness of laser-Doppler flowmetry for non-invasive monitoring of total liver blood flow, the probe being positioned on either the surface or within the liver parenchyma.In 23 Wistar rats and 10 biliary surgery patients, anaesthetized prior to gallbladder removal, liver microcirculation was measured at 4 points on the capsular surface, and consequently at 4 points deep within the parenchyma, using probes connected to a laser-Doppler flowmeter. The findings revealed that laser-Doppler measurements on the liver surface and within the parenchyma were well correlated, as no statistically significant differences were found either in rats or humans. It is concluded that laser- Doppler flowmetry for monitoring of total liver perfusion can be applied either on the capsular surface or within the hepatic parenchyma.

Validation of laser-Doppler flowmetry in measurement of spinal cord blood flow

1989 ◽  
Vol 257 (2) ◽  
pp. H674-H680 ◽  
Author(s):  
P. J. Lindsberg ◽  
J. T. O'Neill ◽  
I. A. Paakkari ◽  
J. M. Hallenbeck ◽  
G. Feuerstein
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Cord Blood ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Microvascular Blood Flow ◽  
Base Line ◽  
Spinal Cord Blood Flow ◽  
Flow Measurements ◽  
Doppler Flowmetry

Laser-Doppler flowmetry (LDF) is a non-invasive method for continuous on-line monitoring of microvascular blood flow. LDF has previously been validated with established methods in various tissues, yet its validity and resolution in the central nervous system (CNS) remain unclear. We compared LDF with the microsphere method (MS) using two independent laser probes placed on the dorsal lumbar spinal cord (L5 laminectomy) of anesthetized rabbits (n = 9). After base-line flow measurements, spinal cord blood flow (SCBF) was increased (up to 50%) with phenylephrine (10-80 micrograms.kg-1.min-1 iv) and decreased (up to 50%) with chlorisondamine (10 mg/kg iv) or other stimuli. The percentage changes of lumbar SCBF and vascular resistance (VR) from the base line obtained by LDF and MS excellently agreed (rBF = 0.86, rVR = 0.94, P less than 0.0001). LDF estimated also the absolute SCBF values parallel to MS (r = 0.77, P less than 0.001). In conclusion, the validity of LDF in estimating the SCBF and dynamic changes of BF and VR is confirmed. Therefore, LDF may prove useful for monitoring CNS microcirculation in normal or pathophysiological states.

Laser-Doppler flowmetry for estimating liver blood flow

1988 ◽  
Vol 254 (4) ◽  
pp. G471-G476 ◽  
Author(s):  
D. Arvidsson ◽  
H. Svensson ◽  
U. Haglund
Keyword(s):  
Blood Flow ◽  
Laser Doppler Flowmetry ◽  
Venous Blood ◽  
Liver Blood Flow ◽  
Laser Doppler ◽  
Venous Blood Flow ◽  
Venous Outflow ◽  
Doppler Flowmetry ◽  
Hepatic Venous Outflow ◽  
Portal Venous Blood

Whether laser-Doppler flowmetry can be used to monitor liver blood flow was evaluated in a porcine model in which portal venous blood flow was followed indirectly by electromagnetic flowmetry applied to the superior mesenteric artery, and total hepatic venous outflow was measured directly by using an extracorporeal circuit. Hepatic venous outflow at rest was 23.5 +/- 5.7 ml.kg body wt-1.min-1. Occlusion of the hepatic arterial supply reduced hepatic laser-Doppler blood flow to 22%, but hepatic venous outflow only to 80%. Portal venous blood flow remained unchanged or increased slightly. Occlusion of the portal vein, on the other hand, decreased hepatic laser-Doppler blood flow values to 37% and hepatic venous outflow to 13%. Increased hepatic venous outflow pressure, caused by a positive end-expiratory pressure or elevation of the draining cannula, reduced flow and caused approximately equal changes in the three variables, as did reduced flow by step-wise bleeding. From these experiments in the pig it is concluded that laser-Doppler flowmetry on the liver surface clearly reflects relative changes of the total liver blood flow, as exemplified in this study, during venous stasis and bleeding. The technique is, however, more sensitive to blood flow changes in the hepatic artery as compared with the portal vein.

scholarly journals Laminar Analysis of Cerebral Blood Flow in Cortex of Rats by Laser-Doppler Flowmetry: A Pilot Study

1997 ◽  
Vol 17 (12) ◽  
pp. 1326-1336 ◽  
Author(s):  
Martin Fabricius ◽  
Nuran Akgören ◽  
Ulrich Dirnagl ◽  
Martin Lauritzen
Keyword(s):  
Blood Flow ◽  
Cerebral Cortex ◽  
Real Time ◽  
Optical Fibers ◽  
Laser Doppler Flowmetry ◽  
Laser Light ◽  
Laser Doppler ◽  
Flow Measurements ◽  
Doppler Flowmetry ◽  
Artificial Brain

Laser-Doppler flowmetry (LDF) is a reliable method for estimation of relative changes of CBF. The measurement depth depends on wavelength of the laser light and the separation distance of transmitting and recording optical fibers. We designed an LDF probe using two wavelengths of laser light (543 nm and 780 nm), and three separation distances of optical fibers to measure CBF in four layers of the cerebral cortex at the same time. In vitro comparison with electromagnetic flow measurements showed linear relationship between LDF and blood flow velocity at four depths within the range relevant to physiologic measurements. Using artificial brain tissue slices we showed that the signal for each channel decreased in a theoretically predictable fashion as a function of slice thickness. Application of adenosine at various depths in neocortex of halothane-anesthetized rats showed a predominant CBF increase at the level of application. Electrical stimulation at the surface of the cerebellar cortex demonstrated superficial predominance of increased CBF as predicted from the distribution of neuronal activity. In the cerebellum, hypercapnia increased CBF in a heterogeneous fashion, the major increase being at apparent depths of approximately 300 and 600 μm, whereas in the cerebral cortex, hypercapnia induced a uniform increase. In contrast, the CBF response to cortical spreading depression in the cerebral cortex was markedly heterogeneous. Thus, real-time laminar analysis of CBF with spatial resolution of 200 to 300 μm may be achieved by LDF. The real-time in depth resolution may give insight into the functional organization of the cortical microcirculation and adaptive features of CBF regulation in response to physiologic and pathophysiologic stimuli.

Laser-Doppler flowmetry reveals rapid perfusion changes in adipose tissue of lean and obese females

2006 ◽  
Vol 291 (5) ◽  
pp. E1025-E1030 ◽  
Author(s):  
P. Wellhöner ◽  
D. Rolle ◽  
P. Lönnroth ◽  
L. Strindberg ◽  
M. Elam ◽  
...  
Keyword(s):  
Blood Flow ◽  
Adipose Tissue ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Whole Body ◽  
Tissue Blood Flow ◽  
Flow Measurements ◽  
Doppler Flowmetry ◽  
Reflex Responses ◽  
Obese Subjects

The present study aimed to evaluate adipose tissue blood flow (ATBF) by means of laser-Doppler flowmetry (LDF) in humans. Lower body negative pressure (LBNP) and straining known to affect epidermal blood flow through the autonomic nervous system were performed in 11 lean and 11 obese female volunteers. ATBF changes were compared between both groups and also discriminated from skin blood flow (SBF) responses of the immediate vicinity. Additionally, LDF measurements were compared with flow measurements using 133xenon washout in 10 lean subjects during whole body cooling. LDF estimations of SBF and ATBF showed a positive correlation to 133Xe during cooling. SBF and ATBF were reduced to the same extent in both lean and obese subjects during LBNP. Straining induced divergent changes in SBF and ATBF: initially SBF decreased while ATBF increased, but toward the end of straining SBF increased above baseline and ATBF returned down to baseline level. Those changes were similar in both weight groups. Interestingly, only in obese subjects, both LBNP and straining were followed by ATBF augmentation, while SBF levels remained stable. In conclusion, LDF compares with 133Xe washout in monitoring ATBF during tonic perfusion changes. Its strength, however, lies in the detection of rapid flow alterations within the subcutaneous tissue, allowing the evaluation of reflex responses of the subcutaneous microcirculation. Interestingly, those rapid changes in SBF and ATBF can be both concordant and discordant. With regard to ATBF, vasoconstrictor components of the reflex responses were similar in lean and obese subjects, whereas vasodilatory responses were more pronounced in obese volunteers.

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