Robust analysis of microcirculatory flowmotion during post-occlusive reactive hyperemia.

BACKGROUND: Flowmotion analysis of the microcirculatory blood flow is a method to extract information about the vessel regulatory function. It has previously shown promise when applied to measurements during a post-occlusive reactive hyperemia. The reperfusion peak and the following monotonic decline introduces false low frequencies that should not be interpreted as rhythmic vasomotion effect. AIM: To develop and validate a robust method for flowmotion analysis of post-occlusive reactive hyperemia signals. METHOD: The occlusion-induced reperfusion response contains a typical rapid increase followed by a monotonic decline to baseline. A mathematical model is proposed to detrend this transient part of the signal to enable further flowmotion analysis. The model is validated in 96 measurements on healthy volunteers. RESULTS: Applying the proposed model corrects the flowmotion signal without adding any substantial new false flowmotion components. CONCLUSION: Future studies should use the proposed method or equivalent when analyzing flowmotion during post-occlusive reactive hyperemia to ensure valid results.

Evaluation of peri-implant perfusion in patients who underwent avascular augmentation or microvascular reconstruction using laser Doppler flowmetry and tissue spectrophotometry: a prospective comparative clinical study.

OBJECTIVES: The aim of this study was to evaluate the peri-implant perfusion, such as oxygen saturation, the relative amount of hemoglobin, and blood flow, in implants placed in pristine bone and avascular and microvascular grafts using a non-invasive measurement method. MATERIALS AND METHODS: A total of 58 patients with 241 implants were included. Among them, 106 implants were based in native bone (group I), 75 implants were inserted into avascular bone grafts (group II), and 60 implants were placed in microvascular bone grafts (group III). Gingival perfusion was measured using laser Doppler flowmetry and tissue spectrophotometry (LDF-TS). Implants with signs of gingival inflammation were excluded to analyze healthy implant perfusion in different bony envelopes. RESULTS: The mean values for oxygen saturation, relative hemoglobin levels, and blood flow did not differ significantly between the groups (p = 0.404, p = 0.081, and p = 0.291, respectively). There was no significant difference in perfusion between implants that were surrounded by mucosa and implants based within cutaneous transplants (p = 0.456; p = 0.628, and p = 0.091, respectively). CONCLUSION: No differences in perfusion were found between implants inserted into native bone and implants involving bone or soft tissue augmentation. However, implants based in avascular and microvascular transplants showed higher rates of peri-implant inflammation. CLINICAL RELEVANCE: Peri-implant perfusion seems to be comparable for all implants after they heal, irrespective of their bony surroundings. Although perfusion does not differ significantly, other factors may make implants in avascular and microvascular transplants vulnerable to peri-implant inflammation.

Analysis of the Pulpal Blood Flow Microdynamics during Prosthetic Tooth Preparation Using Diamond Burs with Different Degrees of Wear.

Pulpal modifications taking place during prosthetic tooth preparation using worn-out burs may represent a risk for the vitality of the dental pulp. The aim of this in vivo study was to evaluate whether the wear of diamond burs has an influence on the vascular microdynamics at the level of the dental pulp, during vertical preparation for zirconia crowns. The study was performed with a split-mouth design and included 32 vital permanent monoradicular teeth (20 maxillary and 12 mandibular), from six subjects, aged between 20 and 50 years. The teeth were randomly assigned to two study groups of 16 teeth each. For prosthetic preparation, new burs were used in the first group, and burs at their 5th use were used in the second group. Four consecutive determinations of the pulpal blood flow by Laser Doppler flowmetry (LDF-laser Doppler MoorLab instrument VMS-LDF2, Moor Instruments Ltd., Axminster, UK) were taken for each tooth included in the study: before the preparation (control values), immediately, at 24 h, and at 7 days after the prosthetic preparation. A four-way ANOVA statistical analysis was applied to analyze the effect of four considered factors (bur wear degree, time of measurement, tooth number, and tooth location) on the pulpal blood flow (PBF). A significant increase in pulpal blood flow compared to the baseline was recorded immediately after preparation (p < 0.01), at 24 h (p < 0.01), and at 7 days (p < 0.05) in both groups, but more pronounced in the case of burs at the 5th use. The blood flow was significantly higher in upper jaw teeth, irrespective of the measurement time. In conclusion, the use of worn-out diamond burs produces lasting modifications in the pulpal blood flow of teeth that undergo prosthetic crown preparation. ISRCTN registry: ISRCTN49594720.

Dynamic Microcirculation Characteristics of Plantar Skin Under Metatarsal Head of Human Foot in Response to Life-Like Pressure Stimulus.

OBJECTIVE: Diabetic foot ulcer (DFU) is a severe complication with high mortality. High plantar pressure and poor microcirculation are considered main causes of DFU. The specific aims were to provide a novel technique for real-time measurement of plantar skin blood flow (SBF) under walking-like pressure stimulus and delineate the first plantar metatarsal head dynamic microcirculation characteristics because of life-like loading conditions in healthy individuals. METHODS: Twenty young healthy participants (14 male and 6 female) were recruited. The baseline (i.e., unloaded) SBF of soft tissue under the first metatarsal head were measured using laser Doppler flowmetry (LDF). A custom-made machine was utilized to replicate daily walking pressure exertion for 5 min. The exerted plantar force was adjusted from 10 N (127.3 kPa) to 40 N (509.3 kPa) at an increase of 5 N (63.7 kPa). Real-time SBF was acquired using the LDF. After each pressure exertion, postload SBF was measured for comparative purposes. Statistical analysis was performed using the R software. RESULTS: All levels of immediate-load and postload SBF increased significantly compared with baseline values. As the exerted load increased, the postload and immediate-load SBF tended to increase until the exerted load reached 35 N (445.6 kPa). However, in immediate-load data, the increasing trend tended to level off as the exerted pressure increased from 15 N (191.0 kPa) to 25 N (318.3 kPa). For postload and immediate-load SBF, they both peaked at 35 N (445.6 kPa). However, when the exerted force exceeds 35 N (445.6 kPa), both the immediate-load and postload SBF values started to decrease. CONCLUSIONS: Our study offered a novel real-time plantar soft tissue microcirculation measurement technique under dynamic conditions. For the first metatarsal head of healthy people, 20 N (254.6 kPa)-plantar pressure has a fair microcirculation stimulus compared with higher pressure. There might be a pressure threshold at 35 N (445.6 kPa) for the first metatarsal head, and soft tissue microcirculation may decrease when local pressure exceeds it.

The influence of immediate intraoperative loading with a splinting component on supporting tissues during a one-stage implant.

OBJECTIVE: Aim: To study the specifics of the impact of immediate intraoperative loading with a splinting component on supporting tissues during a one-stage implantation protocol. PATIENTS AND METHODS: Materials and Methods: In the course of the study, orthopedic treatment was carried out for 55 patients aged 29 to 60 years. The following were performed: cone-beam computed tomography, software planning and intraoral scanning with an optical scanner, one-stage implantation protocol, assessment of implant stability with the Osstell ISQ device, microcirculation study in the peri-implant area using laser Doppler flowmetry (LDF). RESULTS: Results: It was established that around loaded implants there is an increase in blood flow and vasomotor activity of the microcirculatory channel of the supporting tissues, an increase in the volume of bone tissue and an increase in torque, which is the optimal forecast for the acceleration of the pace of osseointegration. CONCLUSION: Conclusions: The use of a splinting component during immediate intraoperative functional masticatory load accelerates the dynamics of bone tissue remodeling processes around the implant, which is an optimal prediction of osseointegration rates in various dental implantation protocols and is consistent with high values of the implant stability coefficient.

[Laser Doppler flowmetry in the diagnosis of chronic mixed blepharitis]. / Lazernaya dopplerovskaya floumetriya v diagnostike khronicheskogo smeshannogo blefarita.

Chronic mixed blepharitis accounts for 51.7% of all ophthalmic diseases. The use of laser Doppler flowmetry (LDF) in the diagnosis of this disease can help establish the initial manifestations of the inflammatory process in the eyelids, which is important for the prevention of possible complications - dry eye disease. PURPOSE: This study was conducted to determine the sensitivity and specificity of the LDF method in the diagnosis of chronic mixed blepharitis based on the study of microcirculatory changes in the eyelid skin. MATERIAL AND METHODS: The study included 23 patients with chronic mixed blepharitis (mean age 67±5.8 years) and 18 healthy volunteers (mean age 63±1.1 years). LDF was performed using the LAZMA MC-1 device. ROC analysis was used to determine sensitivity and specificity. RESULTS: A typical disturbance of the eyelid skin microcirculation was revealed in chronic mixed blepharitis - ischemia - with inhibition of the intensity of the functioning of blood flow regulatory systems and moderate activation of the lymph flow. The sensitivity and specificity of the coefficient of variation (reflecting the vasomotor activity of microvessels) of blood flow was 71.43 and 71.43%, lymph flow - 65.71 and 80.00%; myogenic rhythms of blood flow - 83.33 and 85.71%, lymph flow - 66.67 and 71.43%; neurogenic rhythms of blood flow - 75.00 and 78.57%, lymph flow - 91.67 and 78.57%, respectively. CONCLUSION: Laser Doppler flowmetry of the eyelid skin in combination with clinical, functional and instrumental research methods helped reveal with high sensitivity and specificity the eyelid damage in chronic mixed blepharitis. This method allows assessment of the condition of the eyelids in individuals without diseases of the anterior segment of the eye.

Internal Mammary Artery-saphenous Vein Y Anastomosis in Coronary Artery Bypass Grafting - Is there a Possibility of Coronary Steal?

Recent advances in coronary revascularization include total arterial grafting, however, in a few cases, harvesting the right internal thoracic artery (RITA) is not possible due to various reasons. In such cases, where the aorta is also calcified, few surgeons perform Y anastomosis configuration with the left internal thoracic artery(LITA) and saphenous vein which can have disastrous complications. Our patient is a 65-year-old man who was diagnosed with multivessel coronary disease and presented with a coronary steal during coronary artery bypass grafting surgery. The RITA was not harvested due to osteoporosis sternum. LITA-saphenous vein Y anastomosis configuration was done as the aorta was calcified. The anastomosis was done between the LITA to the left anterior descending (LAD) artery and the Y arm saphenous vein was anastomosed to an obtuse marginal (OM)branch. He developed coronary steal following anastomosis of the Y graft to the OM branch. The patient had ischemic changes inside the operation theatre in LAD territory, hence grafts were revised following which the patient became stable. There is a high possibility of a coronary steal when the caliber of the Y arm does not match with the LITA. LITA-saphenous vein Y anastomosis can cause more complications as the saphenous vein is much bigger in caliber compared to the LITA.

Wearable laser Doppler flowmetry for non-invasive assessment of diabetic foot microcirculation: methodological considerations and clinical implications.

Significance: Type 2 diabetes mellitus (T2DM) is a global health concern with significant implications for vascular health. The current evaluation methods cannot achieve effective, portable, and quantitative evaluation of foot microcirculation. Aim: We aim to use a wearable device laser Doppler flowmetry (LDF) to evaluate the foot microcirculation of T2DM patients at rest. Approach: Eleven T2DM patients and twelve healthy subjects participated in this study. The wearable LDF was used to measure the blood flows (BFs) for regions of the first metatarsal head (M1), fifth metatarsal head (M5), heel, and dorsal foot. Typical wavelet analysis was used to decompose the five individual control mechanisms: endothelial, neurogenic, myogenic, respiratory, and heart components. The mean BF and sample entropy (SE) were calculated, and the differences between diabetic patients and healthy adults and among the four regions were compared. Results: Diabetic patients showed significantly reduced mean BF in the neurogenic (p=0.044) and heart (p=0.001) components at the M1 and M5 regions (p=0.025) compared with healthy adults. Diabetic patients had significantly lower SE in the neurogenic (p=0.049) and myogenic (p=0.032) components at the M1 region, as well as in the endothelial (p<0.001) component at the M5 region and in the myogenic component at the dorsal foot (p=0.007), compared with healthy adults. The SE in the myogenic component at the dorsal foot was lower than at the M5 region (p=0.050) and heel area (p=0.041). Similarly, the SE in the heart component at the dorsal foot was lower than at the M5 region (p=0.017) and heel area (p=0.028) in diabetic patients. Conclusions: This study indicated the potential of using the novel wearable LDF device for tracking vascular complications and implementing targeted interventions in T2DM patients.

Preoperative Angiographic Protocol for the Surgical Management of Spinal Dural Arteriovenous Fistulas: A Technical Nuance for Safe Minimally Invasive Surgery.

BACKGROUND: Interruption of the fistulous point is the goal of treatment of spinal dural arteriovenous fistulas (dAVFs). Microsurgery remains a highly efficient treatment in terms of complete occlusion with the lowest risk of recurrence rate. It is reported that the hardest step involves finding the fistulous site itself, potentially extending surgical access and time and increasing potential postoperative surgical-related complications. The accurate preoperative detection of the shunt and spinal level together is crucial for guiding optimal, fast, and safe microsurgical treatment. METHODS: We describe a preoperative angiographic protocol for achieving a safe and simple resection of spinal dural arteriovenous fistulas based on a 6-year institutional experience of 42 patients who underwent minimally invasive procedures. Two illustrative cases are included to support the technical descriptions. RESULTS: The suspected artery associated with the vascular malformation of interest is studied in our angiographic protocol through nonsubtracted selective acquisitions in lateral projection. The resulting frames are reconstructed with three-dimensional rotational angiography. The implementation of the preoperative angiographic protocol allowed 100% of intraoperative identification of the fistulous point in all cases with the use of a minimally invasive approach. CONCLUSIONS: Nowadays, neurosurgeons advocate for minimally invasive procedures and procedures with low morbidity risk for treatment of spinal dural arteriovenous fistulas. Our preoperative approach for accurate angiographic localization of the fistulous point through nonsubtracted and three-dimensional reconstructed angiography allowed us to achieve safe and definitive occlusion of the shunt.

Measuring tissue oxygen saturation in the orad intestinal segment during equine colic surgery may aid in predicting the occurrence of postoperative ileus.

OBJECTIVE: To assess the histological injury and intestinal microperfusion measured by laser Doppler flowmetry and spectrophotometry (LDFS) of the small intestine orad to a strangulation during colic surgery. ANIMALS: Horses with naturally occurring small intestinal strangulations undergoing colic surgery were included. METHODS: In this prospective clinical trial, intestinal tissue oxygen saturation (tSO2) and tissue blood flow (tBF) were measured by LDFS orad to the strangulation following release of the strangulation (n = 18). The number of horses with postoperative reflux (POR) and the cases that survived until discharge were compared between groups using Fisher's exact test (P < .05). Intestinal biopsies were taken in cases that underwent intestinal resection or intraoperative euthanasia (n = 28). Measurements were compared between injured and noninjured segments with a Mann-Whitney U or t test. RESULTS: The tSO2 and tBF of the orad intestine were lower than previously reported in healthy horses. Horses with low tSO2 of < 35% were significantly more likely to suffer from POR (6/6 cases) compared to cases with tSO2 > 69% (1/6). The number of horses that survived were not statistically different between these groups (2/6 and 6/6). All horses with mucosal injury developed POR (6/6), which was significantly more likely compared to horses without mucosal injury (3/13). No significant difference in tSO2 or tBF could be found between the segments with and without histological injury. CLINICAL RELEVANCE: The results suggest that measuring tSO2 in the orad segment during colic surgery may aid in predicting postoperative issues.

Blood flow ratio in the gastric conduit measured by laser Doppler flowmetry: A predictor of anastomotic leakage after esophagectomy.

Background: Anastomotic leakage after esophagectomy is a common complication. Laser Doppler flowmetry (LDF) can quantitatively evaluate the blood flow in the gastric conduit. Methods: A total of 326 patients who underwent thoracoscopic/robot-assisted esophagectomy followed by gastric conduit reconstruction and end-to-side anastomosis were enrolled. We divided the gastric conduit into zones I (dominated by the right gastroepiploic vessels), II (dominated by the left gastroepiploic vessels), and III (perfused with short gastric vessels). Before pulling up the gastric conduit to the neck, LDF values were measured at the pylorus, the border between zones I and II (zone I/II), the border between zones II and III (zone II/III), and the gastric conduit tip (tip). The blood flow ratio was calculated as the LDF value divided by the LDF value at the pylorus. Results: Anastomotic leakage developed in 32 of 326 patients. Leakage was significantly associated with the blood flow ratio at the tip (p < 0.001), but not at zone I/II, zone II/III, and the anastomotic site. The receiver-operating characteristic curve analysis identified an anastomotic leakage cutoff ratio of 0.41 (at the tip). A multivariate Cox analysis showed that a blood flow ratio <0.41 at the tip was an independent risk factor for anastomotic leakage (p < 0.001). Conclusion: Anastomotic leakage after esophagectomy was significantly associated with the blood flow ratio at the tip of the gastric conduit. Preservation of the blood supply to the tip via the gastric wall might contribute to a decreased incidence of anastomotic leakage.

An Experimental Phototherapy Device for Studying the Effects of Blue Light on Patients with Raynaud's Phenomenon.

Raynaud's phenomenon (RP) is a condition that causes decreased blood flow to areas perfused by small blood vessels (e.g., fingers, toes). In severe cases, ulceration, gangrene, and loss of fingers may occur. Most treatments focus on inducing vasorelaxation in affected areas by the way of pharmaceuticals. Recently, animal studies have shown that vasorelaxation can be induced by non-coherent blue light (wavelength ~ 430-460 nm) through the actions of melanopsin, a photoreceptive opsin protein encoded by the OPN4 gene. To study this effect in humans, a reliable phototherapy device (PTD) is needed. We outline the construction of a PTD to be used in studying blue light effects on Raynaud's patients. Our design addresses user safety, calibration, electromagnetic compatibility/interference (EMC/EMI), and techniques for measuring physiological responses (temperature sensors, laser Doppler flow sensors, infrared thermal imaging of the hands). We tested our device to ensure (1) safe operating conditions, (2) predictable, user-controlled irradiance output levels, (3) an ability for measuring physiological responses, and (4) features necessary to enable a double-blinded crossover study for a clinical trial. We also include in the Methods an approved research protocol utilizing our device that may serve as a starting point for clinical study. We introduced a reliable PTD for studying the effects of blue light therapy for patients suffering from Raynaud's phenomenon and showed that our device is safe and reliable and includes the required measurement vectors for tracking treatment effects throughout the duration of a clinical study.

Reproducibility of Laser Doppler Flowmetry in gingival microcirculation. A study on six different protocols.

OBJECTIVES: Laser Doppler Flowmetry (LDF) is a non-invasive technique for the assessment of tissue blood flow, but increased reproducibility would facilitate longitudinal studies. The aim of the study was to assess the interday reproducibility of Laser Doppler Flowmetry (LDF) at rest, at elevated local temperatures, and with the use of the vasodilator Methyl Nicotinate (MN) in six interconnected protocols for the measurement of the blood supply to the microvascular bed of the gingiva. METHODS: Ten healthy volunteers were included. Interweek LDF measurements with custom-made acrylic splints were performed. Six protocols were applied in separate regions of interest (ROI): 1; basal LDF, 2; LDF with thermoprobe 42 °C, 3; LDF with thermoprobe 45 °C, 4; LDF with thermoprobe 42 °C and MN, 5; LDF with thermoprobe 45 °C and MN and 6; LDF with MN. RESULTS: Intra-individual reproducibility was assessed by the within-subject coefficient of variation (wCV) and the intraclass correlation coefficient (ICC). Basal LDF measurements demonstrated high reproducibility with wCV 11.1 in 2 min and 10.3 in 5 min. ICC was 0.9 and 0.92. wCV after heat and MN was 4.9-10.3 and ICC 0.82-0.93. The topically applied MN yielded increased blood flow. CONCLUSION: This is the first study evaluating the reproducibility of basal LDF compared to single or multiple vasodilatory stimuli in gingiva. Multiple collector fibers probe and stabilizing acrylic splints are recommended. Vasodilatory stimulation showed a tendency toward higher reproducibility. Furthermore, MN yields vasodilation in gingiva.

The Use of Intraoperative Microvascular Doppler in Vascular Neurosurgery: Rationale and Results-A Systematic Review.

Surgical treatment of neurovascular lesions like intracranial aneurysms, arteriovenous malformations and arteriovenous dural fistulas is still associated with high morbidity. Several recent studies are providing increasing insights into reliable tools to improve surgery and reduce complications. Inadvertent vessel compromise and incomplete occlusion of the lesion represent the most possible complications in neurovascular surgery. It is clear that direct visual examination alone does not allow to identify all instances of vessel compromise. Various modalities, including angiography, microvascular Doppler and neurophysiological studies, have been utilized for hemodynamics of flow vessels in proper clipping of the aneurysm or complete obliteration of the lesion. We intended to review the current knowledge about the intraoperative microvascular Doppler (iMDS) employment in the most updated literature, and explore the most recent implications not only in intracranial aneurysms but also in neurovascular lesions like arteriovenous malformations (AVMs) and arteriovenous dural fistulas (AVDFs). According to the PRISMA guidelines, systematic research in the most updated platform was performed in order to provide a complete overview about iMDS employment in neurovascular surgery. Twelve articles were included in the present paper and analyzed according to specific research areas. iMDS employment could represent a crucial tool to improve surgery in neurovascular lesions. The safety and effectiveness of the surgical treatment of neurovascular lesions like intracranial aneurysm and other neurovascular lesions like AVMs and AVDFs requires careful and accurate consideration regarding the assessment of anatomy and blood flow. Prognosis may depend on suboptimal or incomplete exclusion of the lesion.

Acoustic resolution photoacoustic Doppler flowmetry for assessment of patient rectal cancer blood perfusion.

Significance: Photoacoustic Doppler flowmetry offers quantitative blood perfusion information in addition to photoacoustic vascular contrast for rectal cancer assessment. Aim: We aim to develop and validate a correlational Doppler flowmetry utilizing an acoustic resolution photoacoustic microscopy (AR-PAM) system for blood perfusion analysis. Approach: To extract blood perfusion information, we implemented AR-PAM Doppler flowmetry consisting of signal filtering and conditioning, A-line correlation, and angle compensation. We developed flow phantoms and contrast agent to systemically investigate the flowmetry's efficacy in a series of phantom studies. The developed correlational Doppler flowmetry was applied to images collected during in vivo AR-PAM for post-treatment rectal cancer evaluation. Results: The linearity and accuracy of the Doppler flow measurement system were validated in phantom studies. Imaging rectal cancer patients treated with chemoradiation demonstrated the feasibility of using correlational Doppler flowmetry to assess treatment response and distinguish residual cancer from cancer-free tumor bed tissue and normal rectal tissue. Conclusions: A new correlational Doppler flowmetry was developed and validated through systematic phantom evaluations. The results of its application to in vivo patients suggest it could be a useful addition to photoacoustic endoscopy for post-treatment rectal cancer assessment.

Idiopathic cervical dystonia and non-motor symptoms: a pilot case-control study on autonomic nervous system.

PURPOSE: Non-motor symptoms, such as sleep disturbances, fatigue, neuropsychiatric manifestations, cognitive impairment, and sensory abnormalities, have been widely reported in patients with idiopathic cervical dystonia (ICD). This study aimed to clarify the autonomic nervous system (ANS) involvement in ICD patients, which is still unclear in the literature. METHODS: We conducted a pilot case-control study to investigate ANS in twenty ICD patients and twenty age-sex-matched controls. The Composite Autonomic System Scale 31 was used for ANS clinical assessment. The laser Doppler flowmetry quantitative spectral analysis, applied to the skin and recorded from indices, was used to measure at rest, after a parasympathetic activation (six deep breathing) and two sympathetic stimuli (isometric handgrip and mental calculation), the power of high-frequency and low-frequency oscillations, and the low-frequency/high-frequency ratio. RESULTS: ICD patients manifested higher clinical dysautonomic symptoms than controls (p < 0.05). At rest, a lower high-frequency power band was detected among ICD patients than controls, reaching a statistically significant difference in the age group of ≥ 57-year-olds (p < 0.05). In the latter age group, ICD patients showed a lower low-frequency/high-frequency ratio than controls at rest (p < 0.05) and after mental calculation (p < 0.05). Regardless of age, during handgrip, ICD patients showed (i) lower low-frequency/high-frequency ratio (p < 0.05), (ii) similar increase of the low-frequency oscillatory component compared to controls, and (iii) stable high-frequency oscillatory component, which conversely decreased in controls. No differences between the two groups were detected during deep breathing. CONCLUSION: ICD patients showed ANS dysfunction at clinical and neurophysiological levels, reflecting an abnormal parasympathetic-sympathetic interaction likely related to abnormal neck posture and neurotransmitter alterations.

Peripheral and ocular microvascular alterations in systemic sclerosis: observations from capillaroscopic assessments, perfusion peripheral analysis, and optical coherence tomography angiography.

To investigate the correlations between finger microvascular morphology and function in patients with systemic sclerosis (SSc) and the status of ocular microcirculation, as detected by nailfold videocapillaroscopy (NVC), laser speckle contrast analysis (LASCA), and optical coherence tomography angiography (OCTA). The enrollment included 32 SSc patients, classified according to the 2013 ACR/EULAR criteria, and 27 sex- and age-matched healthy controls. The participants underwent comprehensive rheumatological and ophthalmological examinations, as well as NVC, LASCA, and OCTA analysis on the same day at a single center from March to October 2022. SSc patients receiving intravenous prostanoids cycles were assessed at least 1 month after infusion. Statistical analysis was conducted using Stata® 15.1. Significant direct correlations were observed between the mean capillary number (at NVC) and the mean perfusion of fingers (at LASCA) with the retinal and choroidal perfusion (at OCTA) (all p < 0.05). In addition, a significantly reduced retinal and choroidal perfusion was detected in SSc patients vs controls (all p < 0.05). Interestingly, diffuse cutaneous SSc (dcSSc) patients exhibited a lower choroidal perfusion (p = 0.03) but an increased choroidal thickness (CT) than limited cutaneous SSc patients (p < 0.001). CT was increased also in patients with positive Scl70 antibodies and with a history of digital ulcers directly correlating with disease duration (r = 0.67, p = 0.001). Finally, the combination of LASCA and OCTA parameters showed a significant discrimination capacity between SSc patients and controls, with an area under the curve of 0.80 [95% CI (0.74, 0.87)]. Peripheral microvascular damage is correlated with impaired ocular microcirculation in SSc. The increased choroidal thickness observed in dcSSc may be related to local sub-endothelial extracellular matrix deposition. The combined analysis of choroidal and fingertip perfusion offers preliminary insights that may complement traditional diagnostic methods for SSc.

Oxygen Saturation or Tissue Oxygen Determinations on Skin Whose Viability is at Risk.

The triad of ischaemia, neuropathy, and infection are among the principal causes of lower extremity wounds that are commonly prevalent in patients with diabetic foot (DF) a condition in which peripheral arterial disease commonly co-exists. The prevalence of this condition is increasing globally and with it, the mounting costs of its management. One aspect of management is saving limbs and or digits, a crucial part of this process is assessing tissue viability of skin which is a focus of this review: there are other aspects which are well described in the literature. Amputations are offered to limit the damage resulting from acute/chronic ischaemia. Holstein measured skin perfusion pressure using a radioisotope clearance technique to describe critically ischaemic skin; he found 30 mm Hg as the threshold above which healing may reliably be expected. Recent advances in vascular surgery and related technology have informed evidence-based advice to revascularize and save limbs; in practice, this may leave a wound in the distal skin unhealed; managing these raises questions of tissue viability. Much effort has been made to manage, prevent and to better understand these lower extremity wounds using measurements of tissue oxygen, oxygen saturation and skin imaging. The measurement techniques and their relevant merits are examined in this article. Advances in wound management systems and protocols can also facilitate the repair processes, and those which can have a particular impact on restoring or maintaining tissue perfusion are also discussed in the article.

The effect of intraoperative cerebral oxygen desaturations on postoperative cerebral oxygen metabolism in neonates and infants a pilot study.

INTRODUCTION: Cerebral oxygen desaturation during pediatric surgery has been associated with adverse perioperative outcomes. The aim of this pilot study was to analyze the frequency and severity of intraoperative cerebral oxygen desaturations and their impact on postoperative cerebral oxygen metabolism in neonates and infants undergoing pediatric surgery. METHODS: In a prospective pilot study, intra- and postoperative regional cerebral oxygen saturation and blood flow were measured noninvasively using a device combining laser Doppler flowmetry and white-light-spectrometry. Thirty-seven consecutive neonates and infants undergoing noncardiac surgery under general anesthesia for more than 30 min and necessity for invasive arterial blood pressure monitoring were included. Patients with pre-known congenital structural heart disease or cerebral disease were excluded. Continuously brain monitor recording was started in sedated patients before induction of anesthesia (preoperative baseline) and was completed 1 h postoperatively in the PICU in sedated, intubated, and mechanically ventilated states at the PICU (postoperative state). Baseline and postoperative state for cerebral fractional tissue oxygen extraction and approximated cerebral metabolic rate of oxygen were calculated. RESULTS: Seventeen (46%) of the 37 studied neonates and infants suffered from intraoperative periods of regional cerebral oxygen desaturation below 20% of the baseline (event group). Severity of cerebral desaturations was median 4.0%min/h [range 0.1-58.7; interquartile range [IQR] 0.99-21.29]. In the event group, the duration of surgery was significantly longer (median 135 min [range 11-260; IQR 113.5-167.0] vs median 46.5 min [range 11-180; IQR 30.5-159.3]; difference of -62.94; 95% confidence interval [CI] -105.17 to -20.71; p = .021). In the event group, cerebral fractional tissue oxygen extraction (median 0.41 [range 0.20-0.55; IQR 0.26-0.44] vs. median 0.27 [range 0.11-0.41; IQR 0.20-0.31]; difference of -0.11; 95% CI -0.17 to -0.05; p = .001) and approximated cerebral metabolic rate of oxygen (median 6.15 arbitrary unit [range 2.69-12.07; IQR 5.12-7.21] vs. median 4.14 arbitrary unit [range 1.78-7.86; IQR 3.82-6.31]; difference of -1.76; 95% CI -3.03 to -0.49; p = .009) were significantly higher and the cerebral regional oxygen saturation (median 58.99% [range 44.87-79.1; IQR 54.26-72.61] vs median 70.94% [range 57.9-86.13; IQR 67.07-76.59]; difference of 10.01; 95% CI 4.13-15.90; p = .002) significantly lower after surgery compared to the nonevent group. DISCUSSION: The increase of approximated cerebral metabolic rate of oxygen could indicate an elevated oxidative energy metabolism in the "stressed" brain, due to repair processes. The increased cerebral fractional tissue oxygen extraction fits with the decreased NIRS cerebral oxygenation. Our data suggest that an increase in cerebral oxygen metabolism was the cause. CONCLUSION: Cerebral oxygen desaturation during major surgery in neonates and infants is associated with early postoperative increased cerebral oxygen extraction and possibly increased cerebral oxygen metabolism.

Evaluation of the effect of different desensitizers on pulpal blood flow after full crown preparation using laser Doppler flowmetry: a randomized clinical trial.

This study aims to evaluate the effect of Teethmate, Bifluoride 12, and Copal Varnish on the treatment of dentin hypersensitivity and the pulpal blood flow using laser Doppler flowmetry (LDF) after full crown preparations. Eighteen patients with 42 teeth with dentine hypersensitivity after full crown preparations were randomly treated with Teethmate, Bifluoride 12, and Copal Varnish. Dentine hypersensitivity was measured using a visual analog scale (VAS) and Schiff air index (SAI). LDF was used to assess the pulpal blood flow and results were recorded in perfusion units (PU). All measurements were performed at baseline, 5 min, 7 days, and 1 month after the application of desensitizers. Data were statistically analyzed by Wilcoxon and two-way ANOVA tests (p < 0.05). There was no significant difference between the tested desensitizers regarding VAS and PU values. VAS values decreased significantly at 7 days and 1 month after the application of desensitizers compared to baseline in all groups. The decrease in PU values significantly differed only in the Copal Varnish group at 5 min and 7 days after the application of the desensitizer (p < 0.05). A statistically significant difference was found between different times regarding SAI scores in all groups (p < 0.05). Teethmate, Bifluoride 12, and Copal Varnish showed similar effectiveness on dentine hypersensitivity and pulpal blood flow. Long-term clinical trials with larger sample sizes and histological studies are needed to evaluate their impacts on pulpal status.