scholarly journals Local Heating as a Predilatation Method for Measurement of Vasoconstrictor Responses with Laser-Doppler Flowmetry

2011 ◽  
Vol 18 (3) ◽  
pp. 214-220 ◽  
Author(s):  
JOAKIM HENRICSON ◽  
ERIK TESSELAAR ◽  
YASHMA BAIAT ◽  
GERT NILSSON ◽  
FOLKE SJÖBERG
1987 ◽  
Vol 11 (2) ◽  
pp. 80-84 ◽  
Author(s):  
S. L. E. Fairs ◽  
R. O. Ham ◽  
B. A. Conway ◽  
V. C. Roberts

Accurate and objective assessment of amputation level in the lower limb plays an important role in patient management. Laser Doppler flowmetry (LDF) is a new and noninvasive technique for skin blood flow measurement and has been used pre-operatively in 25 patients undergoing amputation for vascular disease and in five normal controls. Baseline flux measurements were made at room temperature on the medial aspect of legs and then again after local heating of the skin for five minutes. Transcutaneous oxygen measurements were made at the same site for comparison and amputation level in patients selected on this basis. Significant differences (p<0.001) in TcPO2 values were found between controls (10.9±0.5kPa), below-knee (BK) amputees (6.0±1.5kPa) and above-knee (AK) amputees (1.5±0.6kPa). Baseline LDF flux did not differ significantly between any group. Heated flux values did however show a significant difference (p<0.005) between controls (52.4±23.5) and both BK (20.6±9.2) and AK groups (8.1±7.7) and also between the amputee groups. The relative increase in flux (heated flux/baseline flux) differed significantly between the BK (3.3±1.5) and AK (1.2±0.3) groups (p<0.001) and between these two and the controls (11.2±5.4) (p<0.001). The correlation between relative increase in flux and TcPO2 was 0.7 (p<0.001). It is concluded that laser Doppler flowmetry used in conjunction with thermal stressing could provide a quick, simple and non-invasive method for objectively determining amputation level in the lower limb.


Burns ◽  
2020 ◽  
Vol 46 (1) ◽  
pp. 104-109 ◽  
Author(s):  
Dominik Bender ◽  
Stephanie Tweer ◽  
Frank Werdin ◽  
Jens Rothenberger ◽  
Adrien Daigeler ◽  
...  

Author(s):  
P. A. Glazkova ◽  
S. A. Terpigorev ◽  
D. A. Kulikov ◽  
N. A. Ivanova ◽  
A. A. Glazkov

Background.Hypertension (HTN) is associated with impaired skin microcirculation. Laser Doppler flowmetry is an objective, quantitative, instrumental method that allows evaluating skin microcirculation. However, the method was not widely used clinically due to high variability of perfusion and small difference between healthy people and HTN patients and, as a consequence, low diagnostic signifcance.Objective.To provide the grounds for the approaches increasing the informative value of skin microcirculation measurement by laser Doppler flowmetry in HTN patients.Design and methods.The study involved HTN patients (n = 13, the median age was 60 (49; 63) years) and young otherwise healthy volunteers without HTN (n = 12, the median age 26 (25; 27) years). Microcirculation measurement was performed by laser Doppler flowmetry using LAKK-02 device. Registration of microcirculation on the forearm skin was carried out during the occlusionheating test. The Mann-Whitney test was used to compare the parameters in two groups. The diagnostic accuracy of the method for the inverse classifcation of the subjects was evaluated using ROC analysis.Results.In HTN patients, the median baseline perfusion was 3,1 (1,84; 4,31) perfusion units (PU), in healthy volunteers — 4,29 (3,66; 8,14) PU (p = 0,04). The median area under the microcirculation curve for the frst 2 minutes of heating in HTN patients was 1206,7 (813; 1449) PU × s, in healthy volunteers — 1552,3 (1310; 1624) PU × s (p = 0,035). In healthy volunteers, the heating increased the perfusion by 596 % (386%; 878%), and in HTN patients perfusion increased only by 265% (180 %; 318%) (p = 0,01). The relative increase in perfusion during postocclusion hyperemia with continued heating compared with the baseline in healthy volunteers was 651% (493 %; 999%), and in HTN patients — 302 % (182 %; 436%) (p = 0,005). Thus, when comparing the average parameters for each period in the occlusion-heating test, only basic perfusion showed signifcant differences. However, when changed from absolute to relative parameters (the increase in microcirculation in relation to the vasodilating effects), the difference was signifcant. Moreover, sensitivity achieved was 75 % and specifcity — 84,6% (the inverse classifcation of groups).Conclusions.The physiological (the local heating of the forearm skin at a rate of 2 degrees Celsius per second, a combination of vasodilating effects) and mathematical (the transition from absolute to relative values) approaches provided an increase of the informative value of the laser Doppler flowmetry, as well as its sensitivity and specifcity.


VASA ◽  
2015 ◽  
Vol 44 (6) ◽  
pp. 458-465 ◽  
Author(s):  
David Balaz ◽  
Andrea Komornikova ◽  
Peter Kruzliak ◽  
Peter Sabaka ◽  
Ludovit Gaspar ◽  
...  

Abstract. Background: The aim of this study was to evaluate the vasodilatation and vasomotion response to local heating in the cutaneous microcirculation of the ankle, dorsum of foot and forearm. Recently, it has been suggested that this response differs between the forearm and the leg. Probands and methods: Twenty-nine young healthy adults were recruited. They underwent measurement by laser Doppler flowmetry (LDF) in three sites of the body (ankle, dorsum of foot, forearm). Percentage change of the median flow of the skin before and after provocation and normalised perfusion flow to maximal dilation (cutaneous vascular conductance - CVC % Max) during short provocation test were monitored. Spectral analysis of laser Doppler flowmetry signals was performed using the fast Fourier transform algorithm. Results: Significant differences were found in CVC % Max between ankle/dorsum (45.18 ± 6.38% Max vs. 51.24 ± 6.87% Max, respectively; p < 0.05) and between ankle/forearm (45.18 ± 6.38% Max vs. 54.49 ± 5.37% Max, respectively; p < 0.05). Percentage change of flux after provocation has revealed significant differences between ankle/dorsum (394.1 ± 204.5% vs. 577.4 ± 273.5%, respectively; p < 0.05) and ankle/forearm (394.1 ± 204.5% vs. 637.1 ± 324.7%, respectively; p < 0.05). Total spectral activity of vasomotion has differed between ankle/dorsum and ankle/forearm: 69.59 [49.58 - 96.04] vs. 93.01 [73.15 - 121.8] (p < 0.05) and 69.59 [49.58 - 96.04] vs. 107.5 [80.55 - 155.8] (p < 0.05), respectively. Conclusions: Cutaneous microcirculation exhibits regional differences. Significant variability of function between ankle and dorsum of foot suggests that leg microcirculation is not uniform.


2017 ◽  
Vol 123 (6) ◽  
pp. 1461-1467 ◽  
Author(s):  
Caroline J. Smith ◽  
Daniel H. Craighead ◽  
Lacy M. Alexander

Microdialysis is a minimally invasive technique often paired with laser Doppler flowmetry to examine cutaneous microvascular function, yet presents with several challenges, including incompatibility with perfusion of highly lipophilic compounds. The present study addresses this methodological concern, with an emphasis on the independent effects of commonly used vehicle dialysis solutions to improve solubility of pharmacological agents with otherwise low aqueous solubility. Four microdialysis fibers were placed in the ventral forearm of eight subjects (4 men, 4 women; 25 ± 1 yr) with sites randomized to serve as 1) control (lactated Ringer’s), 2) Sodium carbonate-bicarbonate buffer administered at physiological pH [SCB-HCl; pH 7.4, achieved via addition of hydrochloric acid (HCl)], 3) 0.02% ethanol, and 4) 2% dimethyl sulfoxide (DMSO). After baseline (34°C), vehicle solutions were administered throughout a standardized local heating protocol to 42°C. Laser Doppler flowmetry provided an index of blood flow. Cutaneous vascular conductance was calculated and normalized to maximum (%CVCmax, sodium nitroprusside and 43°C local heat). The SCB-HCl solution increased baseline %CVCmax (control: 9.7 ± 0.8; SCB-HCl: 21.5 ± 3.5%CVCmax; P = 0.03), but no effects were observed during heating or maximal vasodilation. There were no differences with perfusion of ethanol or DMSO at any stage of the protocol ( P > 0.05). These data demonstrate the potential confounding effects of some vehicle dialysis solutions on cutaneous vascular function. Notably, this study provides evidence that 2% DMSO and 0.02% ethanol are acceptable vehicles with no confounding local vascular effects to a standardized local heating protocol at the concentrations presented. NEW & NOTEWORTHY This study examined the independent effects of common vehicle solutions on cutaneous vascular responses. A basic buffer (SCB-HCl) caused baseline vasodilation; 2% DMSO and 0.02% ethanol had no effects. This highlights the need for considering potential confounding effects of solubilizing solutions when combined with low aqueous soluble pharmacological agents. Importantly, DMSO and ethanol do not appear to influence cutaneous vascular function during baseline or local heating at the concentrations studied, allowing their use without confounding effects.


VASA ◽  
2005 ◽  
Vol 34 (4) ◽  
pp. 243-249 ◽  
Author(s):  
Drinda ◽  
Neumann ◽  
Pöhlmann ◽  
Vogelsang ◽  
Stein ◽  
...  

Background: Prostanoids are used in the treatment of Raynaud’s phenomenon and acral perfusion disorders secondary to collagenosis. In subjective terms, intravenous administration of these agents produces success in more than 50% of patients. The therapeutic outcome of clinical administration of alprostadil or iloprost may vary from individual to individual. Patients and methods: The following variables were analysed in a cross-over study in 27 patients with collagenosis and Raynaud’s phenomenon: plasma viscosity and erythrocyte aggregation (rheological variables), partial pressure of oxygen and laser Doppler flowmetry in the finger region, and lymphocyte phenotyping and interleukin (IL) determinations (immunological variables). Results: Laser Doppler flowmetry revealed significant differences between patients with secondary Raynaud’s phenomenon and a control group of 25 healthy subjects. Laser Doppler readings did not change significantly as a result of the treatments. Therapy with iloprost produced a reduction in IL-1beta, L-selectin (CD 62 L) and IL-6. Conclusion: The change in immunological variables due to iloprost may explain the long-term effects of prostaglandins in the treatment of Raynaud’s phenomenon. From our results it is not possible to infer any preference for iloprost or alprostadil.


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