Fingertip Blood Flow Research Articles

Integration of orthogonal Fourier profilometry with blood flow mapping for 3D fingertip biometric authentication

We present herein the combination of Fourier transform profilometry based orthogonal projection with a laser speckle imaging method to provide three-dimensional (3D) fingertip blood flow imaging and shape reconstruction for biometric authentication purposes. In the proposed approach, orthogonal sinusoidal grating patterns with a fixed spatial frequency emanating from a digital projector first illuminate the surface of a person's finger. Then, the projector is blocked and a laser source illuminates the finger. The projector and laser work alternately such that only one source illuminates the finger at a given time allowing no illumination crosstalk between the two devices. The deformed grating patterns and the diffuse backscattered laser light, respectively, are recorded on the same CCD camera. In the computer, the 3D shape of the finger is reconstructed simultaneously with a blood flow map of the finger. Finally, the images are merged yielding a dynamic flow topography visualization of the person's finger. This dual-modality strategy utilizes the strengths of each imaging method in a complementary way, thus enabling simple 3D shape recovery and characterization of a specific user, and increasing the specificity of authentication security. The method is experimentally validated on both human and fake fingers through VanderLugt optical correlation framework. Overall, the results demonstrate the utility of our proposed approach for biometric authentication. We envision that our optoelectronic setup could be potentially integrated into a wide variety security platform.

Effect of phase change cooling vest on related thermal regulation factors in moderately hot environments

Phase change cooling vests (CV) are mostly developed to improve people's thermal comfort in warm or hot environments. In this paper, the effect of a CV on related thermal regulation factor was studied. Physiological parameters (including skin temperature, sweat rate, fingertip blood flow, and ear canal temperature) and conductive heat flux were measured in three air temperature conditions (27, 29, and 31 °C). Results found that compared with no cooling vest (NCV) conditions, the maximum decrement in local skin temperature for the back and chest with CV was 2.5 and 2.1 °C, and for the mean skin temperature (Tmsk), the decrement was 0.8 °C. Simultaneously, the mean conductive heat flux of the back and chest with CV was significantly increased by 28.3% and 234.4%, respectively (p < 0.01). The total sweat rate (SR) of subjects using CV was decreased by 14%–18%. The SR of the forehead was positively correlated with the overall thermal sensation and comfort. With the use of CV, the fingertip blood flow (Qfinger) tended to decrease. As the experimental temperature elevated, the impact of the CV on Qfinger was more effective. However, there was no difference in Qfinger and ear canal temperature between the CV and NCV conditions. The results provided a better understanding of the improving effect of CV on human thermal comfort from the perspective of thermal regulation.

Vascular response to the microcirculation in the fingertip by local vibration with varied amplitude.

Objectives: We investigated the effect of local vibration intensity on the vascular response to the microcirculation of the finger. Materials and methods: We performed hand-transmitted vibration experiments combined with laser Doppler flowmetry (LDF) to measure the blood perfusion signals of fingertips in the vibrated hand and the contralateral middle finger under the same frequency and different amplitude vibration, and to analyze the changes of microcirculatory blood perfusion levels in the fingers, and to investigate the effects of vibration stimulation on the endothelial, neural and myogenic regulatory frequency ranges of fingertips based on wavelet analysis. Furthermore, the transparent silicone films were fabricated and cultured with vascular endothelial cell (EC), which will undergo the local vibration with varied amplitude. And the expression of inflammatory factors was detected in the ECs. Results: Low-frequency vibration leads to a decreased blood flow in fingertip, and the degree of reduction in fingertip blood flow increases as the amplitude gradually increases, and the period required for blood flow to return to normal level after hand-transmitted vibration gradually increases. The decrease in blood flow is more pronounced in the vibrating hand than in the contralateral hand. In addition, nuclear factor-κB (NF-κB) expression increased significantly with the increase of vibration amplitude. Conclusion: High amplitude vibrations caused the inflammatory reaction of ECs which will lead to the altered endothelial regulatory activity. The endothelial regulatory activity is closely related to the blood perfusion in the microcirculation.

Peripheral Microvascular Abnormalities Associated with Open-Angle Glaucoma

To investigate peripheral microvascular abnormalities associated with patients with open-angle glaucoma (OAG). This was a cross-sectional study. Patients with OAG and controls. All subjects underwent detailed ophthalmic evaluation, including Humphrey visual field (HVF) tests and swept source OCT. To evaluate peripheral microvascular abnormalities, nailfold capillaroscopy (NFC) and laser Doppler imaging (LDI) were performed. The presence of microhemorrhages, tortuous capillaries, dilated capillaries, avascular areas, and the capillary density, among other characteristics, were recorded using NFC; fingertip blood flow (FBF) was measured using LDI at different time points, before and 1, 10, and 20 minutes after exposure to a cold stimulus. In addition, venous blood samples were collected to measure serum endothelin-1 (ET-1) concentrations as well as serum autoantibodies. Presence of microhemorrhages, tortuous capillaries, and dilated capillaries; FBF; ET-1; and autoantibodies. Sixty-eight subjects (43 patients with OAG and 25 controls) were enrolled in the study. Microhemorrhages were found in the nail bed of 65.1% of the patients with OAG compared with 25.0% of the controls (P= 0.003). There was a significant difference in the mean FBF at the baseline in patients with OAG versus controls (293.6 ± 100.2 vs 388.8 ± 52.0 perfusion units, respectively, P < 0.001), together with a significant decrease in the mean FBF 10 and 20 minutes after cold stimulus in patients with OAG in comparison to controls (P < 0.001 for all comparisons). There was a positive correlation between mean baseline FBF and HVF mean deviation (r= 0.27, P= 0.03) and between mean baseline FBF and average retinal nerve fiber layer thickness (r=0.44, P= 0.001). Neither the analysis of ET-1 concentrations (P= 0.71) nor the autoantibodies measurements (P > 0.05, for all) showed any difference between the 2 groups. Significant peripheral microvascular abnormalities were found in patients with OAG compared to controls, suggesting that microvascular changes might play a role in the pathogenesis of the disease. In addition, part of these peripheral microvascular abnormalities seems to be correlated with both functional and structural glaucomatous damage. The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Characterization Speckle Effect on Measurement of Blood Flow Using Sensor Based on Self-Mixing Interferometry

The applications of Self-Mixing Interferometry (SMI) have been popular in many fields, including biomedical signals. The self-mixing effect occurs from the coherent back-coupling of the reflected or scattered lights from a target surface. The reflected lights will be detected by a photodiode which has been integrated in one device with the laser. That's why the SMI sensor is quite practical, affordable and simple. However, SMI has the serious problem with the presence of speckle effect in measured signal. The speckle effect produced by the human tissue is called “biospeckles.” The biospeckles observed from the skin tissues contain information about the blood flow in dermal capillarities, heartbeat, and others. These biospeckle patterns cause random modulations that will be detected as random amplitude and spectrum by photodiode. In this paper we present a technique to characterize speckle effect on measurement of blood flow in fingertip using sensor based on Self-Mixing Interferometry (SMI). We used a laser diode 785 nm as a light source and a constant current of 70 mA as a current source which is irradiated on the skin tissue in the fingertip. Then, the backscattered light reenters the laser cavity and it will be detected by photodiode. The SMI signal with speckle effect will be processed by Continuous Wavelet Transform for reconstruction and detection fringe. Signal processing results show that the number of detected speckle fringes depends largely on determining the number of wavelet waves and the scale used. The fringe pattern resulting from the reconstruction of the signal can be used to determine the frequency of speckles due to object movement. The average speckle frequency of fingertip is 0,5-0,7 Hz

Abstract P088: Race is Associated with Endothelial Responses to Acute Mental Stress

Introduction: Endothelial dysfunction is associated with short term and long term cardiovascular events. African Americans (AA) have worse cardiovascular outcomes than Non-African Americans (NAA). AAs have higher chronic stress exposure due to socioeconomic deprivation which may affect vascular responses to stress and contribute to health disparities. Our hypothesis was that AA would have abnormal microvascular function after a standardized mental stress as compared to NAA. Methods: We evaluated 692 patients (208 AA) with confirmed coronary artery disease (CAD), who underwent a standardized mental stress challenge. Endothelial function measurements were obtained before and 30 minutes after mental stress testing using a speaking task. Reactive hyperemia index (RHI) was measured using peripheral arterial tonometry (PAT) (Itamar Inc) as the ratio of hyperemic to baseline finger-tip microvascular blood flow signal. Flow-mediated dilation (FMD) was measured using ultrasound as the ratio of hyperemic to baseline brachial artery diameter. Results: As compared to NAA, AA patients were younger, had lower levels of education, and income, and a higher prevalence of co-morbidities. AA patients prior to stress had similar mean RHI (2.07 vs 2.13, p=0.3) but lower mean FMD (3.54 vs 4.76, p=0.0005) as compared to NAA. However, after mental stress, mean RHI was significantly lower in AA, (1.98 vs 2.2, p=0.0002) and mean FMD continued to be lower in AA (2.87 vs 3.81, p=0.005). After adjusting for baseline RHI in addition to age, sex, BMI, cardiovascular risk factors, and depression in a multivariable model, race remained significantly associated with post-stress RHI (p= 0.004). However, race was no longer associated with post-stress FMD after adjusting for pre-stress FMD. (p=0.37). Conclusion: AA patients with CAD, compared with NAA, have worse baseline endothelial-dependent function, which persists after mental stress. Furthermore, AA have a more pronounced decrease in endothelial function with mental stress compared with NAA. Whether this more adverse vascular reactivity with stress is implicated in race-based disparities in cardiovascular disease requires further study.

Skin temperature oscillation model for assessing vasomotion of microcirculation

It has been proved that there exists a certain correlation between fingertip temperature oscillations and blood flow oscillations. In this work, a porous media model of human hand is presented to investigate how the blood flow oscillation in the endothelial frequency band influences fingertip skin temperature oscillations. The porosity which represents the density of micro vessels is assumed to vary periodically and is a function of the skin temperature. Finite element analysis of skin temperature for a contra lateral hand under a cooling test was conducted. Subsequently, wavelet analysis was carried out to extract the temperature oscillations of the data through the numerical analysis and experimental measurements. Furthermore, the oscillations extracted from both numerical analyses and experiments were statistically analyzed to compare the amplitude. The simulation and experimental results show that for the subjects in cardiovascular health, the skin temperature fluctuations in endothelial frequency decrease during the cooling test and increase gradually after cooling, implying that the assumed porosity variation can represent the vasomotion in the endothelial frequency band.

Microvascular abnormalities in patients with early systemic sclerosis: less severe morphological changes than in patients with definite disease

Objectives: To evaluate the morphological and functional abnormalities of the microcirculation associated with markers of vascular injury in patients with early systemic sclerosis (SSc).Method: Forty-six patients with early SSc were compared with 80 patients with definite SSc, 40 patients with primary Raynaud’s phenomenon (PRP), and 45 healthy subjects. Widefield nailfold capillaroscopy (NFC) (10–25 × magnification), videocapillaroscopy (200 × magnification), and laser Doppler imaging (LDI) assessment were performed in all participants. The number of capillaries/mm, enlarged, giant and ramified capillaries, microhaemorrhages, and the avascular score were determined by widefield NFC and videocapillaroscopy. Fingertip blood flow (FBF) was measured using LDI before and after cold stimulus (CS). Serum endothelin-1 (ET-1), von Willebrand factor (vWF), and transforming growth factor beta-1 (TGF-β1) were measured by enzyme-linked immunosorbent assay (ELISA).Results: Upon both widefield NFC and videocapillaroscopy, patients with early SSc showed significantly higher numbers of capillaries/mm, lower enlarged and giant capillaries, and a lower avascular score than definite SSc patients (p < 0.001). They also had more enlarged capillaries, microhaemorrhages and a higher avascular score compared to PRP and controls (p < 0.001). FBF before and after CS were significantly higher in controls than in PRP, early SSc, and definite SSc patients (p < 0.001), with no difference between early and definite SSc. Serum levels of ET-1, vWF, and TGF-β1 were similar between early and definite SSc patients.Conclusions: Early SSc patients showed functional changes and vascular injury marker levels similar to patients with established disease. Nonetheless, the morphological changes were less severe in early SSc, thus providing an opportunity for further prevention of vasculopathy progression.

Influence of indoor and outdoor temperatures on the fingertip blood flow rate

A total of 58 healthy subjects participated to elucidate the influence of indoor and outdoor temperatures on blood flow. After walking outdoors for 20min, the blood flow rate of a subject was measured. The subject then entered a classroom and studied for 120min, and afterwards, the blood flow rate was measured again. The subjects were exposed to outdoor temperature ranging from −2.5 to 33.7°C. During the summer, the average blood flow rate after walking outdoors was 45.95±25.790TPU (tissue perfusion units); after the class, this decreased to 36.14±21.837TPU (p<0.05). During the autumn, the blood flow rate decreased from 27.69±12.334TPU to 12.47±12.255TPU (p<0.001). When the outside air temperature was below 3°C, the blood flow rate indoors increased significantly from 6.74±3.540TPU to 13.95±11.522TPU (p<0.05). In a comfortable and healthy environment, the blood flow rate was not constant but fluctuated between 15TPU and 40TPU.

Determination of the amplitude and phase relationships between oscillations in skin temperature and photoplethysmography-measured blood flow in fingertips

It is well established that skin temperature oscillations in fingertips coexist with blood flow oscillations and there is a certain correlation between them. At the same time, the reasons for differences in waveform and the delay between the blood flow and temperature oscillations are far from being fully understood. In this study we determine the relationships between spectral components of the blood flow and temperature oscillations in fingertips, and we ascertain the frequency dependences of amplitude attenuation and delay time for the temperature oscillations. The blood flow oscillations were considered as a source of thermal waves propagating from micro-vessels towards the skin surface and manifesting as temperature oscillations. The finger temperature was measured by infrared thermography and blood flow was assessed by photoplethysmography for ten healthy subjects. The time–frequency analysis of oscillations was based on the Morlet wavelet transform. The frequency dependences of delay time and amplitude attenuation in temperature compared with blood flow oscillations have been determined in endothelial (0.005–0.02 Hz) and neurogenic (0.02–0.05 Hz) frequency bands using the wavelet spectra. We approximated the experimental frequency dependences by equations describing thermal wave propagation through the medium and taking into account the thermal properties and thickness of a tissue. Results of analysis show that with the increase of frequency f the delay time of temperature oscillations decreases inversely proportional to f1/2, and the attenuation of the amplitude increases directly proportional to exp f1/2. Using these relationships allows us to increase correlation between the processed temperature oscillations and blood flow oscillations from 0.2 to 0.7 within the frequency interval 0.005–0.05 Hz. The established experimental and theoretical relationships clarify an understanding of interrelation between the dynamics of blood flow and skin temperature, and define possibilities and limitations of temperature measurements as a method of blood flow assessment in extremities.

The effect of indoor plants on human comfort

There is growing evidence to support the notion that plants can play an important role in providing a higher quality living environment. This study conducted a series of experiments to investigate the effects of characteristics, such as colour, odour and size of plants on human comfort, which was evaluated by a satisfaction survey and physiological measurements. Different kinds of plants with different levels of colour (green, tint and multicolour), odour (no odour, slight scent and strong scent) and size (small, medium and large) were chosen for the experiment design. A survey of participants’ satisfaction degree as well as measurements from electroencephalogram (EEG), electrocardiogram (ECG), oxyhaemoglobin saturation, fingertip blood flow, skin resistance and respiration rate were utilized to illustrate the response of participants to the environments either with different plants or without plants. The results demonstrated that an interior office with plants was preferred over an office without plants. The environments with green, slightly scented and small plants were reported as the most favourite conditions. The EEG and oxyhaemoglobin saturation showed significant changes when plant conditions varied. These outcomes provided design strategies for incorporating the plants into the interior office spaces and also provided the physiological variables to evaluate human comfort in the outside environment.

A Novel Model to Predict Cutaneous Finger Blood Flow via Finger and Rectal Temperatures

To generate a model that predicts fingertip blood flow (BF(f) ) and to cross-validate it in another group of subjects. We used fingertip temperature (T(f)), forearm temperature minus T(f) (T(For-f)), rectal temperature (T(re)), and their changes across time ((lag) T) to estimate BF(f). Ten participants (six male, four female) were randomly divided into "model" and "validation" groups. We employed a passive hot-cold water immersion protocol during which each participant's core temperature increased and decreased by 0.5°C above/below baseline during hot/cold conditions, respectively. A hierarchical multiple linear regression analysis was introduced to generate models using temperature indicators and (lag) T (independent variables) obtained from the model group to predict BF(f) (dependent variable). Mean BF(f) (109.5 ± 158.2 PU) and predicted BF(f) (P-BF(f)) (111.4 ± 136.7 PU) in the model group calculated using the strongest (R(2) = 0.766, p < 0.001) prediction model [P-BF(f) =T(f) × 19.930 + (lag4) T(f) × 74.766 + (lag4) T(re) × 124.255 - 447.474] were similar (p = 0.6) and correlated (r = 0.880, p < 0.001). Autoregressive integrated moving average time-series analyses demonstrated a significant association between P-BF(f) and BF(f) (R(2) = 0.381; Ljung-Box statistic = 8.097; p < 0.001) in the validation group. We provide a model that predicts BF(f) via two practical temperature indicators that can be implemented in both clinical and field settings.

The Effect of Altering Skin-Surface Cooling Speeds on Vasoconstriction and Shivering Thresholds

Both core and skin temperatures contribute to steady-state thermoregulatory control. Dynamic thermoregulatory responses trigger aggressive defenses against rapid thermal perturbations. These responses potentially complicate interpretation of thermoregulatory studies and could slow induction of therapeutic hypothermia. We thus tested the hypothesis that rapid external skin-cooling triggers vasoconstriction and shivering at higher mean skin temperatures than slow or moderate rates of skin cooling. Eleven healthy volunteers were cooled at 3 skin-cooling rates using forced air or/and conductive cooling in random order. One day volunteers received slow (≈2°C/h) skin cooling, and on another day, they received both medium (≈4°C/h) and fast (≈6°C/h) skin cooling. An endovascular heat-exchanging catheter maintained core temperature. Fingertip blood flow ≤0.25 mL/min defined onset of vasoconstriction; sustained ≥25% increase in oxygen consumption defined onset of shivering. Results were evaluated with repeated-measures analysis of variance, with P < 0.05 representing statistical significance. Volunteers were 25 ± 5 years of age (mean ± SD), 175 ± 7 cm tall, and weighed 63 ± 10 kg. Core temperature remained constant (≈37°C) throughout each study day. At vasoconstriction, mean skin temperatures were 33.2°C (95% confidence interval [CI]: 32.0°C, 34.4°C), 33.5°C (95% CI: 32.3°C, 34.7°C), and 33.0°C (95% CI: 31.4°C, 34.6°C) at slow, medium, and fast skin-cooling rates, respectively. Mean skin temperatures at shivering were also comparable: 31.4°C (95% CI: 30.3°C, 32.5°C), 31.5°C (95% CI: 30.2°C, 32.8°C), and 30.7°C (95% CI: 28.9°C, 32.5°C), respectively. Onset of vasoconstriction and shivering occurred at similar mean skin temperatures with all 3 cooling rates. Aggressive surface cooling can thus be used in thermoregulatory studies and for induction of therapeutic hypothermia without provoking dynamic thermoregulatory defenses.

Discussion of “Core cooling and thermal responses during whole-head, facial, and dorsal immersion in 17 °C water”

1. The rate of oesophageal temperature reduction and the heat loss from the head were less in the second 30 min of cooling than in the first 30 min. This was despite no increase in metabolic rate and a lessening in the rate of vasoconstriction (going by the slope of fingertip blood flow and the change in fingertip temperature). Is the extent of vasoconstriction (even though the rate was lessening) sufficient to explain the reduced rate of oesophageal temperature reduction and heat loss in the second 30 min? Or is there something else going on which slowed up the heat loss? 2. With regard to the core cooling increase with facial compared to dorsal immersion, could some of the difference also be attributable to airway heat loss? With facial cooling, presumably part of the snorkel tubing passed through the water which may have meant that the inspired air was cooler than in the facial cooling condition where perhaps none of the snorkel tubing was in the water.

Core cooling and thermal responses during whole-head, facial, and dorsal immersion in 17 °C water

This study isolated the effects of dorsal, facial, and whole-head immersion in 17 degrees C water on peripheral vasoconstriction and the rate of body core cooling. Seven male subjects were studied in thermoneutral air (approximately 28 degrees C). On 3 separate days, they lay prone or supine on a bed with their heads inserted through the side of an adjustable immersion tank. Following 10 min of baseline measurements, the water level was raised such that the water immersed the dorsum, face, or whole head, with the immersion period lasting 60 min. During the first 30 min, the core (esophageal) cooling rate increased from dorsum (0.29 ± 0.2 degrees C h-1) to face (0.47 ± 0.1 degrees C h-1) to whole head (0.69 ± 0.2 degrees C h(-1)) (p < 0.001); cooling rates were similar during the final 30 min (mean, 0.16 ± 0.1 degrees C h(-1)). During the first 30 min, fingertip blood flow (laser Doppler flux as percent of baseline) decreased faster in whole-head immersion (114 ± 52% h(-1)) than in either facial (51 ± 47% h-1) or dorsal (41 ± 55% h(-1)) immersion (p < 0.03); rates of flow decrease were similar during minutes 30 to 60 (mean, 22.5 ± 19% h(-1)). Total head heat loss over 60 min was significantly different between whole-head (120.5 ± 13 kJ), facial (86.8 ± 17 kJ), and dorsal (46.0 ± 11 kJ) immersion (p < 0.001). The rate of core cooling, relative to head heat loss, was similar in all conditions (mean, 0.0037 ± 0.001 degree C kJ(-1)). Although the whole head elicited a higher rate of vasoconstriction, the face did not elicit more vasoconstriction than the dorsum. Rather, the progressive increase in core cooling from dorsal to facial to whole-head immersion simply correlates with increased heat loss.

Laser Doppler Imaging para quantificação do fluxo sanguíneo de polpa digital em condições basais e após estímulo frio em pacientes com esclerose sistêmica

The objective of this study was to investigate the dynamic behavior of the blood flow of the microvascular circulation of the fingertips before and after two cold stimuli (CS), using Laser Doppler Imaging with different intensities in patients with systemic sclerosis (SSc) and in healthy individuals. Fourteen SSc patients (51.2 ± 5.5 years) with Raynaud's phenomenon and 12 healthy controls (44.8 ± 9.0 years) were included in this study. Two CS protocols (submersion of the hands in water at 10 ºC or 15 ºC for 1 minute) were performed on the same day. Mean fingertip blood flow (FBF) of four digits of the left hand was measured using LDI (Moor LDI-VR, Moor Instruments) at baseline and at 1, 4, 10, 25, and 40 minutes after CS. Baseline blood flow was significantly lower in both CS protocols in SSc patients when compared to controls (312.9 ± 102.7 vs 465.4 ± 135.4 PU, P = 0.006 at 15 ºC; 305.2 ± 121.0 vs 437.9 ± 119.8 PU; P = 0.01 at 10 ºC). In the control group, a significant decrease in FBF after CS, when compared to baseline, was observed 1 minute (P = 0.001) after CS at 15 ºC and at 1 (P = 0.005) and 25 minutes (P = 0.001) after CS at 10 ºC. In SSc patients, a significant decrease in FBF was observed in both CS protocols at 1, 4, and 10 minutes (P < 0.000; P = 0.002; P = 0.014, after CS at 15 ºC; P < 0.000; P = 0.004; P = 0.001, after CS at 10 ºC). Laser Doppler Imaging showed lower baseline fingertip perfusion and further reduction after CS in SSc patients compared to controls. Quantification of fingertip blood flow by LDI may be useful in the longitudinal monitoring of the disease status and therapeutic interventions in SSc.

Pathophysiology underlying irritable bowel syndrome -From the viewpoint of dysfunction of autonomic nervous system activity-

Although irritable bowel syndrome (IBS) is the most common gastrointestinal disease and is found in up to 50% of patients referred to gastroenterologists, its pathogenesis remains unexplained. Lately most attention has been focused on visceral hypersensitivity related to dysfunction of the autonomic nervous system. Although there have been many reports regarding the autonomic nervous system in IBS patients, the results have not always been consistent. In many studies, increased sympathetic nervous system activity and decreased parasympathetic nervous system activity have been the most frequently noted differences when IBS patients are compared with healthy controls. There are also some differences among IBS symptom subgroups and some differences between men and women. Data from previous studies have been inconsistent, with complicating factors resulting in difficulties in classification and the possibility of multiple physiological pathways for a similar symptom picture. Further studies based on the Rome III criteria are required to evaluate whether or not autonomic functions significantly differ from each other. However, although there are many methods of measurement for evaluation of the autonomic nervous system, there are few of these methods that are not only accurate but also cost-effective, non-invasive, and easy to perform. Recently, we developed a new method with the abovementioned advantages for measuring fingertip blood flow in evaluating the autonomic nervous system by continuous-wave Doppler sonography. Using this method, we found that abnormal fingertip blood flow responses suggested the presence of excess sympathetic activity.

Characterization of autonomic dysfunction in patients with irritable bowel syndrome using fingertip blood flow

Fingertip blood flow (FTBF) as measured by laser Doppler flowmetry (LDF) measurement is considered an indicator of sympathetic nerve function. We evaluated autonomic function in patients with irritable bowel syndrome (IBS) by assessing FTBF with both LDF and continuous-wave (cw) Doppler sonography. Firstly, the two methods were compared in 40 healthy volunteers. Next, 59 patients with IBS as well as 118 healthy volunteer controls were studied. In the supine position, FTBF in the right index finger was measured with cw Doppler sonography, whereas FTBF in the left index finger was assessed with LDF. After baseline measurement for at least 5 min, the volunteers received sympathetic stimulation from cold stress applied without notification in the form of an icebag (0 degrees C) upon the left forearm for 1 min. The new cw Doppler sonography method can be used in place of the old LDF method for clinical purposes. FTBF velocity before stimulation (V(pre)) was significantly lower in the IBS group than that in the healthy volunteers (P < 0.01). In addition, the time required for FTBF to return to V(pre) after stimulation was significantly longer in the IBS group than that in the control group. (P = 0.02). Thus, measurement of FTBF with cw Doppler sonography can be useful in the assessment of sympathetic nerve function. The IBS patients showed an abnormal FTBF response suggesting the presence of excess sympathetic activity.

Comparison of Effects of Vitamin E and Wen-jing-tang (Unkei-to), An Herbal Medicine, on Peripheral Blood Flow in Post-menopausal Women with Chilly Sensation in the Lower Extremities: A Randomized Prospective Study

We examined the association between blood flow and chilly sensation in the lower extremities, comparing the changes in blood flow induced by the vitamin E and herbal therapy (Wen-jing-tang) in perimenopausal women with chilly sensation. One hundred sixty-one perimenopausal women aged 42-61 years (mean: 50.4 +/- 3.8 years) with chilly sensation in the lower extremities participated in the study. The participants were randomized for treatment with Wen-jing-tang or a vitamin E preparation containing 600 mg tocopherol nictinate per day for 8 weeks. Blood flow measurement was performed by laser Doppler fluxmetry to determine tissue under the jaw, in the middle finger, and in the third toe. Wen-jing-tang significantly increased the peripheral blood flow in the skin surface in the tiptoe (12.8 +/- 8.8, p = 0.0068) from basal levels (6.0 +/- 5.1), although no significant change was observed in the blood flow in fingertip or under the jaw during treatment. The rate of increase of blood flow in the skin surface of in the lower extremities was significantly higher in the Wen-jing-tang treating group (116.4 +/- 46.5%) than in the vitamin E group (39.8 +/- 21.3%) (p < 0.0001). When the effects of herbal treatment and vitamin E treatment were compared in the subjects with baseline upper extremity blood flow above the mean + 1.5 SD, mean blood flow through the upper extremities was found to have been significantly decreased after Wen-jing-tang treatment (from 57.7 +/- 4.8 to 43.1 +/- 4.2, p = 0.0277), whereas it remained unchanged after treatment with vitamin E. Classical monographs described Wen-jing-tang as being particularly useful in curing chilly sensation in lower extremities. The present study using a laser Doppler fluxmeter demonstrated that treatment with this herbal medicine significantly increased blood flow through the periphery of lower extremities in patients with chilly sensation. It also showed that this herbal medicine suppresses excessive blood flow through the upper half of the body and thus stimulates restoration of physiological distribution of blood flow throughout the entire body.

Reliability of Fingertip Skin-surface Temperature and its Related Thermal Measures as Indices of Peripheral Perfusion in the Clinical Setting of the Operating Theatre

During the perioperative period, evaluation of digital blood flow would be useful in early detection of decreased circulating volume, thermoregulatory responses or anaphylactoid reactions, and assessment of the effects of vasoactive agents. This study was designed to assess the reliability of fingertip temperature, core-fingertip temperature gradients and fingertip-forearm temperature gradients as indices of fingertip blood flow in the clinical setting of the operating theatre. In 22 adult patients undergoing abdominal surgery with general anaesthesia, fingertip skin-surface temperature, forearm skin-surface temperature, and nasopharyngeal temperature were measured every five minutes during the surgery. Fingertip skin-surface blood flow was simultaneously estimated using laser Doppler flowmetry. These measurements were made in the same upper limb with an IV catheter (+ IV group, n=11) or without an IV catheter (-IV group, n=11). Fingertip blood flow, transformed to a logarithmic scale, significantly correlated with any of the three thermal measures in both the groups. Their rank order as an index of fingertip blood flow in the -IV group was forearm-fingertip temperature gradient (r=-0.86) > fingertip temperature (r=0.83) > nasopharyngeal-fingertip temperature gradient (r=-0.82), while that in the +IV group was nasopharyngeal-fingertip temperature gradient (r=-0.77) > fingertip temperature (r=0.71) > forearm-fingertip temperature gradient (r=-0.66). The relation of fingertip blood flow to each thermal measure in the -IV/group was stronger (P<0.05) than that in the +IV group. In the clinical setting of the operating theatre, using the upper limb without IV catheters, fingertip skin-surface temperature, nasopharyngeal-fingertip temperature gradients, and forearm-fingertip temperature gradients are almost equally reliable measures of fingertip skin-surface blood flow.