Search Results (90)

Background: Cold feet syndrome is characterized by hypersensitivity of sympathetic nerves to cold stimuli, resulting in vasoconstriction and reduced peripheral blood flow. This condition causes an intense cold sensation, particularly in the extremities. Although hormonal changes (e.g., during childbirth or menopause) and psychological stress have been implicated, the mechanisms and effective treatments remain unclear. Methods: Ninety adult volunteers were randomized into three groups based on the type of heating mat applied to the feet, with surface temperatures gradually increased from 20 °C to 50 °C. Group A (control) used non-FIR electric mats, Group B used carbon FIR mats, and Group C used loess bio-ball FIR mats. Blood flow (mL/min/100 g) and epidermal temperature (°C) in the left big toe (LBT) and right big toe (RBT) were measured before and after heating or FIR exposure using laser Doppler flowmetry and infrared thermometers. Results: No significant changes in blood flow or skin temperature were observed in Group A. In Group B, blood flow increased by 15.07 mL/min/100 g in the LBT (from 4.12 ± 2.22 to 19.19 ± 5.44) and by 14.55 mL/min/100 g in the RBT (from 4.26 ± 2.29 to 18.81 ± 4.29). In Group C, blood flow increased by 32.86 mL/min/100 g in the LBT (from 4.23 ± 1.64 to 37.09 ± 6.04) and by 32.63 mL/min/100 g in the RBT (from 4.20 ± 1.61 to 36.83 ± 6.48). Epidermal temperature also increased significantly in Group C. All changes in Groups B and C were statistically significant (p < 0.05), with Group C showing the most prominent enhancement. Conclusions: The loess bio-ball mat significantly increased both peripheral blood flow and epidermal temperature compared to the electric and carbon mats. These findings suggest that FIR emitted from loess bio-balls may enhance peripheral circulation through hypothalamus thermogenic response and nitric oxide (NO)-dependent pathways and could serve as a complementary and non-invasive intervention for individuals with poor blood flow. Full article

Background/Objectives: Endoscopic lumbar sympathectomy (ELS) is the definitive treatment for primary plantar hyperhidrosis (PPLH). This study analyzed the mid-term clinical outcomes and technical factors related to ELS. Methods: Retrospective reviews of patients who had ELS for PPLH between July 2019 and May 2023 were analyzed. The study period was categorized into three eras based on the timing when laser Doppler flowmetry (LDF) and PMR (psoas muscle relaxation) were applied; period A represented the initial surgical approach, period B included LDF, and period C included LDF and PMR during surgery. The impacts of these techniques on operative and short-term outcomes were assessed. Additionally, risk factor analysis was performed to find relevant factors related to the reappearance of plantar sweating in long-term follow up. As most patients underwent endoscopic thoracic sympathectomy (ETS) as well, risk assessment for compensatory hyperhidrosis was also investigated. Results: A total of 474 patients were included, and the numbers of patients by periods were as follows: n = 28 in period A, n = 198 in period B, and n = 248 in period C. Operating times were significantly different, with proportional decreases seen with the introduction of LDF and PMR (p < 0.001). In the long-term, reappearance of plantar sweating was noted in 21 patients (4.4%). Risk factors for the reappearance of plantar sweating included an age over 35 years [odds ratio {OR} (95% confidence interval {CI}) 4.57 (1.56–13.40), p = 0.006] and a history of lumbar sympathetic ganglion block (LSGB) prior to ELS [OR (95% CI), 269 (29.30–2460), p < 0.001]. Of 474 patients, 390 (82.3%) patients underwent both ETS and ELS. Risk factors for compensatory hyperhidrosis were age >25 years [OR (95% CI) 0.60 (0.40–0.90), p = 0.014] and concomitant ETS [OR (95% CI) 5.63 (1.88–16.90), p = 0.002]. Compensatory hyperhidrosis among patients who only had ELS was less observed (4/24, 16.7%). Conclusions: ELS is highly effective in treating plantar hyperhidrosis, and LDF and PMR improved perioperative outcomes. Age over 35 and a prior history of LSGB were found to be related to worse long-term outcomes of ELS. Our findings suggest that ELS with additional LDF and PMR could improve outcomes for patients with PPLH. Full article

The Coherent Hemodynamic Spectroscopy (CHS) model provides a quantitative framework for modeling cerebral hemodynamics and metabolism, particularly in response to small physiological perturbations. However, in its original approximate formulation it was limited to conditions where parameter changes were constrained to 10–20%, making it unsuitable for modeling extreme physiological disruptions such as cardiac arrest. In this study, we present a detailed discussion of the algorithm using the complete CHS model, which extends the original framework by solving partial differential equations without approximations to handle large non-periodic perturbations. This model was applied to data from a previously published cardiac arrest and cardiopulmonary resuscitation (CPR) study in pigs, where cerebral blood flow changed by 100%. While our prior work demonstrated the utility of this approach for analyzing cerebral microvascular and metabolic parameters, it did not include the algorithmic details necessary for reproducibility and broader application. Here, we address this gap by describing the algorithm’s workflow, including the use of non-linear multivariate optimization, and its ability to recover multiple physiological variables, such as the capillary and venule oxygen saturations, and parameters, such as the capillary oxygen diffusion rate, and arterial oxygen saturation. The latter can be valuable when the pulse oximetry measurements are unavailable due to unstable, weak or absent pulse. This study underscores the importance of non-linear modeling in advancing the application of CHS to extreme physiological conditions and highlights its potential for translational research and clinical innovation. Full article

Background/Objectives: Primary brain tumors are difficult to identify intraoperatively due to their infiltrative character in the marginal zone. Several optical methods have been suggested. Of these, 5-ALA-induced fluorescence visualized through a microscope is the most common. The aim is to present an investigational probe-based optical system and its translation for clinical use, summarize previous studies, and give examples of clinical implementations during resection and burr hole biopsies. Methods: The FluoRa system combines 5-ALA fluorescence spectroscopy with laser Doppler flowmetry (LDF). Probe designs are available for brain tumor resection (hand-held probe) or burr hole needle biopsies (frame-based or navigated). The outer cannulas of biopsy needles are modified with an opening at the tip for simultaneous use with optical probes during insertion along the trajectory. An updated version of FluoRa is introduced and experimentally investigated. Results: Probe-based fluorescence spectroscopy has been successfully translated for clinical use and applied during brain tumor resection (n = 75) and burr hole needle biopsies (n = 47). Forward-looking optical measurements through the biopsy needle reduce the number of trajectories (28/27) compared to prior to insertion (28/20), at the same time that the target for tissue sampling can be identified in situ. Additionally, increased microcirculation is identified along the trajectory with LDF. This is accomplished with FluoRa. Conclusions: Intraoperative probe-based spectroscopic measurements quantify 5-ALA fluorescence and thus identify glioblastoma and lymphoma tissue in situ during resection and burr hole needle biopsies. Full article

Background/Objectives: Patients with psoriasis exhibit endothelial dysfunction (EDy), which increases their cardiovascular risk. Excessive salt intake impairs endothelium-dependent vascular reactivity. However, research on EDy in psoriasis has focused primarily on larger vessels, leaving skin microcirculation unexplored. This study aimed to investigate the effects of a low-salt diet (LS diet, ~3.75 g/day) on microvascular reactivity in patients with chronic plaque psoriasis. Methods: Laser Doppler flowmetry was used to assess skin microcirculation blood flow in response to vascular occlusion (postocclusive reactive hyperemia, PORH), acetylcholine (acetylcholine-induced dilation, AChID), sodium nitroprusside (SNP-induced dilation, SNPID), and local heating (local thermal hyperemia, LTH). Blood and 24 h urine samples were collected for biochemical and inflammatory parameters and dietary adherence monitoring. Results: The results showed significant reductions in systolic (p = 0.021) and mean arterial blood pressure (p = 0.007) after the LS diet. AChID increased by 16% (p = 0.029) regardless of blood pressure changes, especially in normolipemic, normotensive patients without excess visceral fat. Importantly, significant sex differences were observed, with significant improvement in endothelial function observed only in women (p = 0.031 vs. p = 0.477). PORH did not change significantly; however, a Fourier transformation analysis revealed that the endothelial component of the PORH was significantly improved following the LS diet protocol. The duration of psoriasis negatively correlated with changes in AChID (R = −0.46, p = 0.036) and LTH (R = −0.45, p = 0.041) after the LS diet, indicating that prolonged low-grade inflammation reduced endothelial function reversibility. Additionally, lower triglyceride, uric acid, and BMI levels were significant predictors of better endothelial function improvement following the LS diet. Conclusions: This study supports the beneficial effect of the early introduction of an LS diet in the treatment protocols for patients with psoriasis. Full article

Evaluating brain oxygen metabolism during cardiac arrest and cardiopulmonary resuscitation (CPR) is essential for improving neurological outcomes and guiding clinical interventions in high-stress medical emergencies. This study focused on two key indicators of brain oxygen metabolism: the cerebral metabolic rate of oxygen (CMRO₂) and the oxidation state of redox cytochrome c oxidase (rCCO). Using advanced techniques such as hyperspectral near-infrared spectroscopy (hNIRS) and laser Doppler flowmetry (LDF), we conducted a comprehensive analysis of their relationship in pigs during and after cardiac arrest and CPR. Both the entire duration of these experiments and specific time intervals were investigated, providing a detailed view of how these metrics interact. The data reveal a non-linear relationship between rCCO and CMRO₂. Our findings contribute to a deeper understanding of how the brain manages oxygen during critical episodes, potentially guiding future interventions in neurological care and improving outcomes in emergency medical settings. Full article

The development of laser technology has revolutionized dentistry, offering complementary and alternative approaches to traditional techniques. Lasers have been successfully integrated into various dental procedures, enhancing treatment outcomes and patient care. Several types of lasers can increase the acid resistance of enamel, thus preventing caries. Laser fluorescence has been utilized for the pre-operative diagnosis of dental caries, enabling early detection and effective treatment planning. The therapeutic application of lasers in caries treatment aligns with the contemporary philosophy of minimally invasive procedures. Clinicians can use laser Doppler flowmetry as a supplementary tool for pulp vitality testing by detecting pulpal blood flow. Lasers are also employed in various pulp-related interventions, such as managing dentine hypersensitivity and performing root canal therapy. These procedures benefit from the precision and reduced invasiveness provided by laser technology. Furthermore, laser fluorescence serves as an additional tool for subgingival calculus detection. High-power and low-power lasers are used in both nonsurgical and surgical therapies to treat periodontal and peri-implant diseases, oral mucosa conditions, and even cancer based on their specific properties. Lasers are also utilized to accelerate bone regeneration, promote adhesive strength, and remove ceramic brackets. In summary, laser technology has significantly impacted contemporary dentistry by facilitating early diagnosis, minimally invasive treatments, and precise operative procedures, ultimately improving patient outcomes and expanding the scope of dental practice. Full article

Background/Objectives: The autologous reconstruction of the female breast using a microsurgical DIEP flap is a reliable and safe method. To detect impairments early and preserve the microvascular flap through timely revision, a better understanding of physiologic perfusion dynamics is necessary. This exploratory study examines changes in microcirculation in free DIEP flaps within the first 72 h after vascular anastomosis using laser Doppler flowmetry and white-light spectrophotometry. Methods: This single-center study analyzed retro- and prospectively collected data from female patients who underwent uneventful breast reconstruction using a DIEP flap and were monitored using the O2C device (LEA Medizintechnik, Giessen, Germany). Microcirculation was monitored continuously postoperatively for a period of 72 h. Results: A total of 36 patients with a mean age of 48.86 (9.36) years and a mean BMI of 26.78 (4.12) kg/m² received 40 DIEP flaps (four bilateral reconstructions). Microcirculatory blood flow showed a continuous increase, reaching up to 15% above its initial value within the first 72 h following anastomosis. The average tissue oxygen saturation (sO2) and relative hemoglobin (rHB) levels remained fairly stable throughout the study period, with overall reductions of 5.46% and 5.30%, respectively. Conclusions: Autologous breast reconstruction using a microvascular DIEP flap is a safe and reliable technique. This study showed an increase in blood flow over the 72 h study period. At the same time, sO2 and rHb showed stable levels. Deviations in these values could be interpreted as indicators of a perfusion disorder of the microvascular flap. Full article

Background/Objectives: The perioperative interplay between blood pressure, vasopressors, and macrocirculation is well established. However, in the context of free flap surgery, the potential impact of these factors on microvascular flow remains elusive. The aim was to evaluate the impact of norepinephrine administration on the microcirculation of free flaps. Methods: Postoperative systolic blood pressure (sBP), norepinephrine infusion rates (NIRs), and free flap microcirculation were monitored prospectively and analyzed retrospectively in patients receiving free flap surgery who required postoperative intermediate (IMC) or intensive care (ICU). Blood flow, hemoglobin oxygenation (SO₂), and relative hemoglobin levels (rHbs) were measured over a period of 24 hours post-anastomosis by laser-doppler flowmetry and white light spectroscopy using the “Oxygen to See” device (O2C, LEA Medizintechnik, Gießen, Germany). Multivariate analysis was performed to determine the impact of NIR on microvascular flow, adjusting for several confounding factors. Subgroup analysis was conducted by categorizing into three groups based on patients’ postoperative sBP. Results: Flaps were performed in 105 patients with a mean age of 61.46 ± 16.29 years. Postoperatively, an increase in microvascular flow over time was observed across all free flaps, while NIR decreased and sBP maintained stable values. Multivariate analysis revealed that the time post-anastomosis (B = 3.76, p < 0.001), SO₂ (B = 0.55, p < 0.001), rHb (B= −0.79, p < 0.001), female gender (B = 29.25, p = 0.02), and no previous radiation therapy (B = 41.21, p = 0.04) had a significant impact on postoperative microvascular flow in free flaps. NIR, sBP, smoking status, old age, and ASA score showed no significant impact on free flap flow. Further, NIR showed no significant impact on microvascular flow in any of the subgroups investigated. Conclusions: These findings support the safety of using norepinephrine for maintaining stable blood pressure without compromising microvascular flow, offering valuable guidance for postoperative management. Full article

Currently, research related to the visualization of cutaneous vascular changes to heat stress depending on age and gender is limited to methods such as laser Doppler flowmetry and plethysmography, which do not provide any spatially resolved information at high resolution. On the other hand, optical coherence tomography is a real-time, noninvasive, non-contact technique that can visualize internal structures at the level of a few microns and is widely used in ophthalmology to visualize retinal structures, for example. However, the use of OCT in the investigation of skin vasculature heat stress is limited, with no study being conducted with different genders and different age groups. In this study, we propose biospeckle optical coherence tomography (bOCT), which visualizes the structural changes along a temporal scale to visualize the dynamic changes within the skin under heat stress. Heat stress was applied by applying a USB hot pad (40 °C) for five minutes to the palmar forearm of the dominant hand. A swept-source OCT (SS-OCT) operating with a central wavelength of 1310 nm, a bandwidth of 125 nm, and a sweep frequency of 20 kHz was used to obtain OCT structural images at 12.5 fps. From the one hundred OCT structural images recorded for 8 s, the biospeckle image was calculated as a ratio of the standard deviation to the mean of the images. The biospeckle images were obtained before heating, soon after heating, and after 5 min of rest. A total of 20 subjects with an equal number of male and female participants, with 10 in their 20s and the other 10 in their 30s or older, participated in the experiments. The average biospeckle contrast results were compared for significant differences under the three different conditions of before heating, soon after heating, and after rest for different depths, age differences, and genders. With heating, across all subjects at shallow depths within 200 µm or so, possibly in the epidermis–dermis border region, a significant difference was observed in the average contrast between the before-heating and after-rest conditions, with no significant difference seen in the deeper regions. With respect to age groups irrespective of gender, there was only a significant difference in the average contrast between soon after heating and before heating for the younger group, while for the older group, there was significant difference between before heating and soon after heating as well as between before heating and after 5 min of rest. This result suggests that age plays a larger role in the control of vascular dynamics. With respect to gender and irrespective of age, there was significant difference between males and females for both soon after heating and after 5 min of rest, with no significant difference found for before heating. These differences could be explained by hormonal differences that play a larger role in the vascular dynamics of the control of skin under heat stress, though the clear mechanism behind the reason for these gender differences is not clearly understood yet. As for both gender and age, because of the smaller sample size for age and gender combined, more studies are needed to obtain statistically reliable results. In total, our results obtained using bOCT demonstrate that bOCT could be successfully implemented in the study of the environmental effects on skin tissue, and we believe this has potential implications in therapeutic use such warm water immersion. Full article

Perfusion asymmetries have been associated with vascular pathology. Physical activity is a component of vascular health. Here, we investigate the impact of a thirty-day regular home-based physical activity program in older individuals with multiple age-related comorbidities. Eleven participants of both sexes were included. Skin perfusion was assessed in both feet by laser Doppler flowmetry (LDF, for deeper perfusion) and polarized light spectroscopy (PSp, for superficial perfusion). At baseline, participants had significant perfusion differences between right and left feet (p = 0.005 with LDF; p = 0.028 with PSp), which disappeared with activity and reappeared in recovery. After 30 days, both feet showed significant perfusion increases as assessed with LDF (p = 0.005) compared to D0. At this point, the perfusion asymmetry observed at D0 was no longer present. However, the superficial perfusion asymmetry assessed by PSp persisted at D30 (p = 0.028). Data show that regular physical activity positively altered the lower limb perfusion pattern. Systolic pressure and mean arterial pressure were also significantly reduced at D30. These impacts seem to be directly related to the physical activity program introduced in the day-by-day routines of these participants. These also encourage further research on the role of symmetry–asymmetry in prevention, treatment, and rehabilitation in vascular medicine. Full article

Pathologies associated with neural blood disturbance have been reported in patients with chronic nerve compression (CNC) neuropathy. Fluorescein angiography (FAG) and laser Doppler flowmetry (LDF) are effective for real-time peripheral nerve blood flow assessment. However, their reliability in severe neuropathy models in large animals or clinical conditions remains unclear. Initially, we aim to apply FAG to two different CNC animal models and evaluate their characteristics in comparison with those of LDF. In FAG, we quantified the peak luminance at the compression site following fluorescein injection. Then, we positioned the LDF probe at the center of the compression site and recorded the blood flow. Subsequently, we analyzed whether the FAG characteristics obtained in this animal experiment were consistent with those of clinical studies in patients with severe carpal tunnel syndrome (CTS). In the CNC rat model, FAG and LDF effectively monitored reduced neural blood flow over time. We observed significant blood flow reduction using both techniques in a newly developed severe CNC rabbit model. Notably, FAG correlated strongly with the compound muscle action potential (CMAP) amplitude in electrodiagnostic findings, unlike LDF. As a next step, we performed FAG after open carpal tunnel release in clinical cases of CTS. FAG correlated significantly with preoperative CMAP amplitude. This indicates FAG’s importance for assessing nerve blood flow during surgery, potentially improving diagnostic accuracy and surgical outcomes. Full article

Background: Free muscle flaps can develop significant postoperative edema and wound exudation, thereby increasing interstitial pressure and potentially compromising microcirculation. While concerns exist regarding negative pressure wound therapy (NPWT) to compress free flaps and hinder monitoring, recent studies have indicated a reduction in edema and an increase in blood flow. Objective: To compare microcirculation in free latissimus dorsi muscle (LDM) flaps dressed with and without NPWT. Methods: This retrospective cohort study analyzed prospectively collected data of patients who received free LDM flap reconstruction. Patients were separated into two groups according to management with or without NPWT. Microcirculation was evaluated continuously for up to 72 h utilizing laser doppler flowmetry and tissue spectrometry. Results: In total, n = 61 patients (26 females, 35 males) with an average age of 56.90 (17.4) years were included. NPWT was applied in 12 patients, while a regular cotton dressing was used in 49 patients. Overall, no significant differences in the number of minor and major complications were observed between groups. Both groups showed an increase in microvascular flow over the investigated time period. The flow showed higher absolute values in the NPWT group, reaching statistical significance at 12 h post-anastomosis, p = 0.038. There was a tendency for lower rHb values in the NPWT group, without reaching statistical significance. Conclusions: The presented study confirms the increase in microvascular flow after NPWT application. Whilst ensuring continuous free flap monitoring utilizing laser doppler flowmetry and spectrometry, the data further support the safety of NPWT application without risking vascular compromise due to external compression. Full article

Photoacoustics can provide a direct measurement of light absorption by microalgae depending on the photosynthesis pigment within them. In this study, we have performed photoacoustic flowmetry on living microalgae cells to measure their flow characteristics, which include flow speed, flow angle, flow direction, and, more importantly, the photoacoustic absorption spectrum, all by observing the photoacoustic Doppler power spectra during their flowing state. A supercontinuum pulsed laser with a high repetition frequency is used as the light source: through intensity modulation at a specified frequency, it can provide wavelength-selectable excitation of a photoacoustic signal centered around this frequency. Our approach can be useful to simultaneously measure the flow characteristics of microalgae and easily discriminate their different species with high accuracy in both static and dynamic states, thus facilitating the study of their cultivation and their role in our ecosystem. Full article

Background: The prevalence of peripheral arterial disease and the number of revascularization procedures performed in symptomatic patients are steadily increasing. However, uncertainties remain regarding hemodynamic monitoring after revascularization and the prediction of clinical outcomes. This study aimed to investigate hemodynamic parameters with a focus on the microvasculature. Methods: This prospective, single-center study included 29 patients (15 with intermittent claudication [IC] and 14 with chronic limb-threatening ischemia [CLTI]). Before and after the revascularization procedure, in addition to the ankle–brachial index (ABI), microperfusion parameters, including microvascular blood flow, capillary oxygen saturation (SO₂), and relative hemoglobin content (rHb), were assessed with lightguide spectrophotometry combined with laser Doppler flowmetry using an oxygen-to-see (O2C) device in the horizontal and elevated leg positions. Results: At baseline, SO₂ in the elevated leg position was significantly lower in patients with CLTI than in those with IC (p = 0.0189), whereas the other microcirculatory parameters and ABI values were not significantly different. Patients with diabetes mellitus had a higher flow rate than those without in the horizontal leg position (p = 0.0162) but not in the elevated leg position. After successful revascularization, the flow increased immediately and significantly in both positions, whereas SO₂, rHb, and the ABI did not. Conclusions: Elevated leg SO₂ was significantly lower in CLTI than in clinically compensated peripheral arterial disease, whereas microvascular flow was a suitable surrogate parameter indicating successful revascularization. In studies using surgical or interventional revascularization procedures, noninvasive hemodynamic monitoring of the microcirculation at the foot level might be beneficial. Full article