Real-Time Remote Health Monitoring Systems Using Body Sensor Information and Finger Vein Biometric Verification: A Multi-Layer Systematic Review.

The development of wireless body area sensor networks is imperative for modern telemedicine. However, attackers and cybercriminals are gradually becoming aware in attacking telemedicine systems, and the black market value of protected health information has the highest price nowadays. Security remains a formidable challenge to be resolved. Intelligent home environments make up one of the major application areas of pervasive computing. Security and privacy are the two most important issues in the remote monitoring and control of intelligent home environments for clients and servers in telemedicine architecture. The personal authentication approach that uses the finger vein pattern is a newly investigated biometric technique. This type of biometric has many advantages over other types (explained in detail later on) and is suitable for different human categories and ages. This study aims to establish a secure verification method for real-time monitoring systems to be used for the authentication of patients and other members who are working in telemedicine systems. The process begins with the sensor based on Tiers 1 and 2 (client side) in the telemedicine architecture and ends with patient verification in Tier 3 (server side) via finger vein biometric technology to ensure patient security on both sides. Multilayer taxonomy is conducted in this research to attain the study's goal. In the first layer, real-time remote monitoring studies based on the sensor technology used in telemedicine applications are reviewed and analysed to provide researchers a clear vision of security and privacy based on sensors in telemedicine. An extensive search is conducted to identify articles that deal with security and privacy issues, related applications are reviewed comprehensively and a coherent taxonomy of these articles is established. ScienceDirect, IEEE Xplore and Web of Science databases are checked for articles on mHealth in telemedicine based on sensors. A total of 3064 papers are collected from 2007 to 2017. The retrieved articles are filtered according to the security and privacy of telemedicine applications based on sensors. Nineteen articles are selected and classified into two categories. The first category, which accounts for 57.89% (n = 11/19), includes surveys on telemedicine articles and their applications. The second category, accounting for 42.1% (n = 8/19), includes articles on the three-tiered architecture of telemedicine. The collected studies reveal the essential need to construct another taxonomy layer and review studies on finger vein biometric verification systems. This map-matching for both taxonomies is developed for this study to go deeply into the sensor field and determine novel risks and benefits for patient security and privacy on client and server sides in telemedicine applications. In the second layer of our taxonomy, the literature on finger vein biometric verification systems is analysed and reviewed. In this layer, we obtain a final set of 65 articles classified into four categories. In the first category, 80% (n = 52/65) of the articles focus on development and design. In the second category, 12.30% (n = 8/65) includes evaluation and comparative articles. These articles are not intensively included in our literature analysis. In the third category, 4.61% (n = 3/65) includes articles about analytical studies. In the fourth category, 3.07% (n = 2/65) comprises reviews and surveys. This study aims to provide researchers with an up-to-date overview of studies that have been conducted on (user/patient) authentication to enhance the security level in telemedicine or any information system. In the current study, taxonomy is presented by explaining previous studies. Moreover, this review highlights the motivations, challenges and recommendations related to finger vein biometric verification systems and determines the gaps in this research direction (protection of finger vein templates in real time), which represent a new research direction in this area.

A new method for the assessment of endothelial function with peripheral arterial volume.

BACKGROUND: Currently, many methodological approaches have been developed to assess peripheral endothelial function. However, a development of the noninvasive and automated technique for routinely assessing endothelial function is still required. We evaluated the potential value of a new method to measure peripheral endothelial function with reactive hyperemia peripheral arterial volume (RH-PAV) in patients with chest pain. METHODS: We used a novel oximeter-like probe to detect the peripheral arterial volume (PAV) of the finger and compared it with brachial flow-mediated dilation (FMD) performed in 93 consecutive patients with chest pain. The RH-PAV index was defined as the ratio of the digital pulse volume during reactive hyperemia relative to the baseline. RESULTS: Ninety-three patients (53 men, 58 ± 5 years) completed the study, and 53 patients demonstrated coronary artery disease (CAD) following scheduled coronary angiography. There was a moderate linear relationship between PAV and FMD (r = 0.69, p < 0.01). Similar to FMD, PAV was more impaired in patients who have more cardiovascular risk factors (CRFs). The subjects with CAD had lower PAV and FMD, compared with those without CAD (1.05 ± 0.23 VS. 1.41 ± 0.37, p < 0.01; 6.7% ± 2.9% VS. 10.4% ± 2.9%, p < 0.01, respectively), and the relationships between FMD and PAV were also significant in both CAD (r = 0.54, p < 0.01) and non-CAD (r = 0.62, p < 0.01) patients. CONCLUSIONS: Endothelial function of digital artery assessed with the novel PAV method demonstrated a profile similar to that of brachial artery measured with FMD. The hyperemia PAV was decreased by factors which were considered to impair endothelial function, suggesting that PAV has the potential to be a novel method to study endothelial function.

Skin colour assessment of replanted fingers in digital images and its reliability for the incorporation of images in nursing progress notes.

AIMS AND OBJECTIVES: To determine whether nurses can accurately assess the skin colour of replanted fingers displayed as digital images on a computer screen. BACKGROUND: Colour measurement and clinical diagnostic methods for medical digital images have been studied, but reproducing skin colour on a computer screen remains difficult. DESIGN: The inter-rater reliability of skin colour assessment scores was evaluated. In May 2014, 21 nurses who worked on a trauma ward in Japan participated in testing. METHODS: Six digital images with different skin colours were used. Colours were scored from both digital images and direct patient's observation. The score from a digital image was defined as the test score, and its difference from the direct assessment score as the difference score. Intraclass correlation coefficients were calculated. Nurses' opinions were classified and summarised. RESULTS: The intraclass correlation coefficients for the test scores were fair. Although the intraclass correlation coefficients for the difference scores were poor, they improved to good when three images that might have contributed to poor reliability were excluded. Most nurses stated that it is difficult to assess skin colour in digital images; they did not think it could be a substitute for direct visual assessment. However, most nurses were in favour of including images in nursing progress notes. DISCUSSION: Although the inter-rater reliability was fairly high, the reliability of colour reproduction in digital images as indicated by the difference scores was poor. Nevertheless, nurses expect the incorporation of digital images in nursing progress notes to be useful. This gap between the reliability of digital colour reproduction and nurses' expectations towards it must be addressed. CONCLUSIONS: High inter-rater reliability for digital images in nursing progress notes was not observed. Assessments of future improvements in colour reproduction technologies are required. RELEVANCE TO CLINICAL PRACTICE: Further digitisation and visualisation of nursing records might pose challenges.

Successful treatment of Raynaud's phenomenon and digital ulcers in systemic sclerosis patients with botulinum toxin B injection: Assessment of peripheral vascular disorder by angiography and dermoscopic image of nail fold capillary.

We recently identified the efficacy and safety of a botulinum toxin (BTX)-A/B in Raynaud's phenomenon (RP) and digital ulcers (DU) in Japanese patients with systemic sclerosis (SSc). Detailed assessments of peripheral vascular disorder using angiography and dermoscopic images of nail fold capillaries have not been performed previously. This study aimed to evaluate the effect of BTX-B on SSc-associated peripheral vascular disorder. Two SSc patients who suffered with RP and DU were treated with a BTX-B injection, and thereafter the symptoms of RP were improved and DU healed in both patients. Furthermore, angiography showed an increased blood flow to the palm and fingers, and dermoscopic images of nail fold capillary changes showed improvement. These results suggest that a BTX-B injection may increase peripheral blood flow and improve RP and DU in SSc patients.

The ACRA Anatomy Study (Assessment of Disability After Coronary Procedures Using Radial Access): A Comprehensive Anatomic and Functional Assessment of the Vasculature of the Hand and Relation to Outcome After Transradial Catheterization.

BACKGROUND: The palmar arches serve as the most important conduits for digital blood supply, and incompleteness may lead to digital ischemia when the radial artery becomes obstructed after cardiac catheterization. The rate of palmar arch incompleteness and the clinical consequences after transradial access are currently unknown. METHODS AND RESULTS: The vascular anatomy of the hand was documented by angiography in 234 patients undergoing transradial cardiac catheterization. In all patients, a preprocedural modified Allen test and Barbeau test were performed. Upper-extremity function was assessed at baseline and 2-year follow-up by the QuickDASH. Incompleteness of the superficial palmar arch (SPA) was present in 46%, the deep palmar arch was complete in all patients. Modified Allen test and Barbeau test results were associated with incompleteness of the SPA (P=0.001 and P=0.001). The modified Allen test had a 33% sensitivity and 86% specificity for SPA incompleteness with a cutoff value of >10 seconds and a 59% sensitivity and 60% specificity with a cutoff value of >5 seconds. The Barbeau test had a 7% sensitivity and 98% specificity for type D and a 21% sensitivity and 93% specificity for types C and D combined. Upper-extremity dysfunction was not associated with SPA incompleteness (P=0.77). CONCLUSIONS: Although incompleteness of the SPA is common, digital blood supply is always preserved by a complete deep palmar arch. Preprocedural patency tests have thus no added benefit to prevent ischemic complications of the hand. Finally, incompleteness of the SPA is not associated with a loss of upper-extremity function after transradial catheterization.

Assessment of treatment effects on digital ulcer and blood perfusion by laser speckle contrast analysis in a patient affected by systemic sclerosis.

Laser speckle contrast analysis (LASCA) is a good tool to evaluate the variation in peripheral blood perfusion during long-term follow-up and is able to safely monitor digital ulcer evolution in scleroderma patients. It evaluates blood perfusion in different areas within the skin lesions and surrounding them during standard treatment.

Influence of Fraction of Inspired Oxygen on Noninvasive Hemoglobin Measurement: Parallel Assessment of 2 Monitors.

BACKGROUND: Previous reports have brought specific attention to the relationship between oxygenation of the patient and the accuracy of noninvasive measurement of hemoglobin (Hb) using an optical sensor. This study aimed to assess prospectively the relationship between fraction of inspired oxygen (FIO2) and the bias of the measurement of Hb by the use of 2 different noninvasive monitors compared with the classic invasive technique. METHODS: Forty-four patients were included prospectively. In each individual, Hb level was determined noninvasively by monitor Pronto-7™ (Masimo Corporation, Irvine, CA) and by monitor NBM-200MP™ (OrSense Ltd, Petah-Tikva, Israel), with the probe placed on 2 fingers on the same hand of the patient. Three measures were performed, first under breathing air and 2 others when fraction of expired oxygen rose to 50% ± 5% and to 90 ± 5%. Simultaneously, a nurse collected a venous blood sample, which was sent immediately to the hematology laboratory for Hb measurement. The main outcome measurement was the mean bias between noninvasive and invasive measurements. RESULTS: Results show no change in median bias [interquartile range] with FIO2 for Pronto-7 (from 1.1 g/dL [0.0-2.0] in FIO2 21% to 1.0 g/dL [0.2-1.5] in FIO2 100%), but increasingly negative median bias with increasing FIO2 for NBM-200MP (from -0.3 g/dL [-1.3 to 0.3] in FIO2 21% to -0.8 g/dL [-1.5 to -0.1] in FIO2 100%, P = .04). DISCUSSION: This study showed that noninvasive measurement of Hb could be influenced by inspired fraction of oxygen when the monitor NBM-200MP is used.

Assessment, Treatment, and Prevention Strategies for Hair-Thread Tourniquet Syndrome in Infants.

Hair-thread tourniquets are a rare occurrence but result in significant injury as a hair or thread wraps around a digit, resulting in tissue swelling, pain, or possible tissue ischemia. This condition is often overlooked in the differential diagnosis for a fussy infant. Awareness of this condition will help nurses and other clinicians identify and treat the condition. Some simple prevention strategies can help parents and other caregivers mitigate risk.

Assessment of two alternative standardised tests for the vascular component of the hand-arm vibration syndrome (HAVS).

BACKGROUND: Vibration-induced white finger (VWF) is the vascular component of the hand-arm vibration syndrome (HAVS). Two tests have been standardised so as to assist the diagnosis of VWF: the measurement of finger rewarming times and the measurement of finger systolic blood pressures (FSBPs). OBJECTIVES: This study investigates whether the two tests distinguish between fingers with and without symptoms of whiteness and compares individual results between the two test methods. METHODS: In 60 men reporting symptoms of the HAVS, the times for their fingers to rewarm by 4°C (after immersion in 15°C water for 5 min) and FSBPs at 30°C, 15°C and 10°C were measured on the same day. RESULTS: There were significant increases in finger rewarming times and significant reductions in FSBPs at both 15°C and 10°C in fingers reported to suffer blanching. The FSBPs had sensitivities and specificities >90%, whereas the finger rewarming test had a sensitivity of 77% and a specificity of 79%. Fingers having longer rewarming times had lower FSBPs at both temperatures. CONCLUSIONS: The findings suggest that, when the test conditions are controlled according to the relevant standard, finger rewarming times and FSBPs can provide useful information for the diagnosis of VWF, although FSBPs are more sensitive and more specific.

Symptoms of Raynaud's phenomenon (RP) in fibromyalgia syndrome are similar to those reported in primary RP despite differences in objective assessment of digital microvascular function and morphology.

Symptoms of Raynaud's phenomenon (RP) are common in fibromyalgia syndrome (FMS). We compared symptom characteristics and objective assessment of digital microvascular function using infrared thermography (and nailfold capillaroscopy where available) in patients with FMS (reporting RP symptoms) and primary RP. We retrospectively reviewed the outcome of microvascular imaging studies and RP symptom characteristics (captured using patient-completed questionnaire at the time of assessment) for patients with FMS (reporting RP symptoms) and patients with primary RP referred for thermographic assessment of RP symptoms over a 2-year period. Of 257 patients referred for thermographic assessment of RP symptoms between 2010 and 2012, we identified 85 patients with primary RP and 43 patients with FMS. There were no differences in RP symptom characteristics between FMS and primary RP (p > 0.05 for all comparisons). In contrast, patients with FMS had higher baseline temperature of the digits (32.1 vs. 29.0 °C, p = 0.004), dorsum (31.9 vs. 30.2 °C, p = 0.005) and thermal gradient (temperature of digits minus temperature of dorsum; +0.0 vs. -0.9 °C, p = 0.03) compared with primary RP. Significant differences between groups persisted following local cold challenge. In primary RP, patient reporting "blue" digits, bi-phasic and tri-phasic RP was associated with lower digital perfusion. In contrast, no associations between skin temperature and RP digital colour changes/phases were identified in FMS. Our findings suggest that symptoms of RP in FMS may have a different aetiology to those seen in primary RP. These findings have potential implications for both the classification of RP symptoms and the management of RP symptoms in the context of FMS. Digital colour changes reported by patients might reflect the degree of digital microvascular compromise in primary RP.

Endothelial Dysfunction and Racial Disparities in Mortality and Adverse Cardiovascular Disease Outcomes.

BACKGROUND: The contribution of arterial endothelial dysfunction (ED) to increased cardiovascular disease (CVD) risk among Blacks is not known. HYPOTHESIS: We investigated whether peripheral arterial ED explains racial disparity in CVD events. METHODS: Data from the Heart Strategies Concentrating on Risk Evaluation (Heart SCORE) study was used. Endothelial dysfunction was assessed by the Framingham reactive hyperemia index (fRHI), measured using pulse amplitude tonometry (PAT). Lower values of fRHI indicate more severe ED. The primary outcome of interest was combined CVD events and all-cause mortality. RESULTS: 1454 individuals (62% female, 40% Black, mean age 59 ± 8 years) had available data on fRHI (mean [SD]: 0.74 [0.46]). Over a mean follow-up period of 8.0 ± 2.4 years (11,186 person-years), 116 events were observed. Black race, male sex, smoking, diabetes, blood pressure, triglycerides, C-reactive protein, and interleukin-6 were inversely correlated with fRHI in univariate models. In an unadjusted Cox regression model, fRHI was associated with 20% lower risk of the primary outcome events (hazard ratio [HR] per 1-SD higher fRHI: 0.80, 95% confidence interval [CI]: 0.66-0.97). However, this association was no longer significant after adjustment for CVD risk factors (HR: 0.90, 95% CI: 0.74-1.11). In an age- and sex-adjusted model, Blacks had 1.68 (95% CI: 1.16-2.43) higher risk of primary outcome compared with Whites. This association was not significantly attenuated by addition of fRHI to the multivariable models. CONCLUSION: Black race is associated with increased risk of CVD events and mortality independent of its associations with ED, as measured by PAT.

Exercise and Repeated Testing Improves Accuracy of Laser Doppler Assessment of Microvascular Function Following Shortened (1-minute) Blood Flow Occlusion.

OBJECTIVES: To determine whether stability/accuracy of post-occlusive LDF following shortened, one-minute blood flow occlusion, increases in the post-exercise state or by averaging multiple measurements. METHODS: Six healthy adults (3F) underwent LDF eight times at rest and following exercise, assessing post-occlusive (one-minute occlusion) reactive hyperemia in the cutaneous microcirculation of the forefinger. Measured variables included: pre- and post-occlusion steady-state perfusion (Plat1, Plat2), maximum post-occlusive perfusion (Max), PkT, and the ratio Max/Plat1. RESULTS: Stability/accuracy of all variables improved performing measurements after exercise (p < 0.05 Plat 1, Plat 2, Max and Max/Plat1). PkT and Max/Plat 1 displayed the greatest accuracy at rest (26.6 ± 5.1% and 26.6 ± 4.4% average difference, %Diff, of single measurements from individual "true" means, respectively); for these variables, %Diff improved to 19.5 ± 5.3 and 17.6 ± 2.1, respectively, following exercise. Overall, averaging multiple measurements performed at rest also improved stability/accuracy in all variables. This improvement was comparable to that obtained with a single measurement following exercise. CONCLUSIONS: A standardized exercise stimulus prior to testing significantly improves stability/accuracy of LDF following shortened, one-minute blood flow occlusion. Our results suggest the possibilities of broader applications of exercise to optimize measurements from a variety of skin perfusion methodologies.

An observational cohort study of patients with newly diagnosed digital ulcer disease secondary to systemic sclerosis registered in the EUSTAR database.

OBJECTIVES: This study describes clinical characteristics, prognostic factors, and quality of life in patients with newly diagnosed (incident) digital ulcers (DU). METHODS: Observational cohort study of 189 consecutive SSc patients with incident DU diagnosis identified from the EUSTAR database (22 centres in 10 countries). Data were collected from medical charts and during one prospective visit between 01/2004 and 09/2010. RESULTS: Median age at DU diagnosis was 51 years, majority of patients were female (88%), and limited cutaneous SSc was the most common subtype (61%). At incident DU diagnosis, 41% of patients had one DU and 59% had ≥2 DU; at the prospective visit 52% had DU. Pulmonary arterial hypertension (PAH) and multiple DU at diagnosis were associated with presence of any DU at the prospective visit (odds ratios: 4.34 and 1.32). During the observation period (median follow-up was 2 years) 127 patients had ≥1 hospitalisation. The event rate of new DU per person-year was 0.66, of DU-associated complications was 0.10, and of surgical or diagnostic procedures was 0.12. At the prospective visit, patients with ≥1 DU reported impairment in daily activities by 57%, those with 0 DU by 37%. The mean difference between patients with or without DU in the SF-36 physical component was 2.2, and in the mental component 1.4. DU patients were not routinely prescribed endothelin receptor antagonists or prostanoids. CONCLUSIONS: This real world cohort demonstrates that DU require hospital admission, and impair daily activity. PAH and multiple DU at diagnosis were associated with future occurrence of DU.

Assessment of cardiovascular function from multi-Gaussian fitting of a finger photoplethysmogram.

Monitoring of cardiovascular function on a beat-to-beat basis is fundamental for protecting patients in different settings including emergency medicine and interventional cardiology, but still faces technical challenges and several limitations. In the present study, we propose a new method for the extraction of cardiovascular performance surrogates from analysis of the photoplethysmographic (PPG) signal alone.We propose using a multi-Gaussian (MG) model consisting of five Gaussian functions to decompose the PPG pulses into its main physiological components. From the analysis of these components, we aim to extract estimators of the left ventricular ejection time, blood pressure and vascular tone changes. Using a multi-derivative analysis of the components related with the systolic ejection, we investigate which are the characteristic points that best define the left ventricular ejection time (LVET). Six LVET estimates were compared with the echocardiographic LVET in a database comprising 68 healthy and cardiovascular diseased volunteers. The best LVET estimate achieved a low absolute error (15.41 ± 13.66 ms), and a high correlation (ρ = 0.78) with the echocardiographic reference.To assess the potential use of the temporal and morphological characteristics of the proposed MG model components as surrogates for blood pressure and vascular tone, six parameters have been investigated: the stiffness index (SI), the T1_d and T1_2 (defined as the time span between the MG model forward and reflected waves), the reflection index (RI), the R1_d and the R1_2 (defined as their amplitude ratio). Their association to reference values of blood pressure and total peripheral resistance was investigated in 43 volunteers exhibiting hemodynamic instability. A good correlation was found between the majority of the extracted and reference parameters, with an exception to R1_2 (amplitude ratio between the main forward wave and the first reflection wave), which correlated low with all the reference parameters. The highest correlation ([Formula: see text] = 0.45) was found between T1_2 and the total peripheral resistance index (TPRI); while in the patients that experienced syncope, the highest agreement ([Formula: see text] = 0.57) was found between SI and systolic blood pressure (SBP) and mean blood pressure (MBP).In conclusion, the presented method for the extraction of surrogates of cardiovascular performance might improve patient monitoring and warrants further investigation.

Individual variability analysis of fluorescence parameters measured in skin with different levels of nutritive blood flow.

Fluorescence spectroscopy has recently become more common in clinical medicine. However, there are still many unresolved issues related to the methodology and implementation of instruments with this technology. In this study, we aimed to assess individual variability of fluorescence parameters of endogenous markers (NADH, FAD, etc.) measured by fluorescent spectroscopy (FS) in situ and to analyse the factors that lead to a significant scatter of results. Most studied fluorophores have an acceptable scatter of values (mostly up to 30%) for diagnostic purposes. Here we provide evidence that the level of blood volume in tissue impacts FS data with a significant inverse correlation. The distribution function of the fluorescence intensity and the fluorescent contrast coefficient values are a function of the normal distribution for most of the studied fluorophores and the redox ratio. The effects of various physiological (different content of skin melanin) and technical (characteristics of optical filters) factors on the measurement results were additionally studied. The data on the variability of the measurement results in FS should be considered when interpreting the diagnostic parameters, as well as when developing new algorithms for data processing and FS devices.

The relationship between nailfold capillaroscopic assessment and telangiectasia score with severity of peripheral vascular involvement in systemic sclerosis.

OBJECTIVES: To determine the association of nailfold video-capillaroscopy (NVC) findings and telangiectasia score with digital ulcer (DU) history and severity of peripheral vascular involvement (PVI) in systemic sclerosis (SSc). METHODS: Fifty-nine SSc patients fulfilling Leroy & Medsger criteria were evaluated including telangiectasia score, disease activity and severity scores. NVC was performed according to qualitative (early, active and late patterns) and semi-quantitative assessments. RESULTS: When DU+ and DU- groups were compared; the mean score of capillary number (CN) was 2.0±0.5 vs. 1.4±0.7 (p<0.001), irregularly enlarged capillaries (IEC) was 1.8±0.6 vs. 1.4±0.7 (p<0.05), microangiopathy evolution score (MES) was 2.5±1.5 vs. 1.8±1.0 (p<0.05) and 'early' pattern was significantly less frequent in DU+ patients (1 vs. 9, p=0.016). The frequency of severe-PVI (Medsger severity score of 2-4) was 22% in females (12/54) and 80% in males (4/5). When severe and non-severe groups were compared; the mean score of CN was 2.1±0.4 vs. 1.5±0.7 (p<0.001), MES was 2.8±1.6 vs. 1.8±1.1 (p<0.05) and 'early' pattern was significantly less frequent in patients with severe PVI (0 vs. 9, p=0.049). The mean values of telangiectasia score were similar between groups. CONCLUSIONS: DU history and severe PVI in SSc were associated with capillary loss and microangiopathy. 'Early' NVC pattern was very rare in patients with DU history and was not found in severe PVI. Severe PVI in males was more frequent than females. Telangiectasia scores were not found to be related to PVI. NVC may be a helpful method in the assessment of SSc patients for PVI prognosis, warranting prospective studies.

Finger volume pulse waveforms facilitate reliable assessment of heart rate variability, but not blood pressure variability or baroreflex function.

BACKGROUND: We sought to determine whether heart rate variability (HRV), blood pressure (BP) variability, and baroreceptor-heart rate reflex sensitivity can be reliably assessed using finger volume pulse waveforms obtained from the commercially available EndoPAT device. METHODS: Non-invasive BP (Finometer Pro as a non-invasive standard) and finger volume (EndoPAT) waveforms were recorded in 65 adults (37 ± 14 years; 60% female) and systolic BP and heart rate (HR) time series were derived after calibrating the EndoPAT signal based on systolic and diastolic BP values obtained by a sphygomomanometer. Transfer function analyses were performed to test for coherence between systolic BP and HR time series derived from the Finometer and EndoPAT devices. Time-domain HRV parameters, frequency domain HR and systolic BP variability parameters, and baroreflex sensitivity (sequence technique) were computed from Finometer- and EndoPAT-derived time series and intraclass correlation coefficients (ICC) were calculated. RESULTS: Squared coherence between systolic BP time series derived from the Finometer and EndoPAT devices was low, suggesting poor correlation. In contrast, squared coherence between HR time series derived from the two devices was excellent [High Frequency (HF) = 0.80, Low Frequency (LF) = 0.81], with gain values close to 1.0. ICC values for time- and frequency-domain HRV parameters were excellent (>0.9 except for relative HF HRV, which was 0.77), while ICC values for frequency-domain BP variability parameters and baroreceptor-HR reflex sensitivity were low. CONCLUSIONS: Finger volume pulse waveforms can be used to reliably assess both time-domain and frequency-domain HR variability. However, frequency domain BP variability parameters cannot be reliably assessed from finger volume pulse waveforms using the simple calibration technique used in this study.

Blood circulation in the fingers is aggravated after creating a vascular access for dialysis: assessment using skin perfusion pressure.

Internal vascular shunts for haemodialysis can cause different complications. One of the most serious complications is steal syndrome, which can result in disturbed peripheral circulation causing finger necrosis and lead to amputation. Thus, prevention of these complications is important. Measurement of skin perfusion pressure (SPP) has been used in various clinical settings, including wound-healing management, and its usefulness has been increasingly unveiled. The present study was undertaken to evaluate changes in haemodynamics after internal shunt creation by measuring SPP of the thumb and the little finger before and after surgery in five patients undergoing shunt surgery using the radial artery and the cephalic vein. The study revealed average changes of -22.8 mmHg in thumb SPP. The change in the thumb was statistically significant (p < 0.05). If the effect of surgery and the threshold for wound healing are taken into account, the present results indicate the necessity to pay extra attention to fingers with extremely low preoperative SPP values. For the prevention of serious disturbances of peripheral circulation (e.g. steal syndrome), routine preoperative SPP measurement seems effective for screening of high-risk patients.

Laser Doppler imaging for assessment of microcirculation in juvenile systemic sclerosis.

OBJECTIVES: The objectives of this study were to evaluate the dynamic behaviour of digital skin microvascular blood flow before and after cold stimulation using laser Doppler imaging (LDI) in children and adolescents with RP secondary to juvenile systemic sclerosis (JSS), primary RP (PRP) and healthy controls and to compare functional abnormalities measured by LDI with structural microvascular abnormalities evaluated by nailfold capillaroscopy (NFC). METHODS: Five JSS patients, five children and adolescents with PRP and five healthy controls matched for gender and age were included. All subjects had NFC performed. Finger blood flow (FBF) was measured using the LDI system (Moor Instruments) at baseline and after cold stimulus (CS). RESULTS: There were a decreased number of capillaries, a greater number of enlarged capillaries and a higher deletion score in JSS patients compared with controls and patients with PRP. The mean baseline FBF was significantly lower in JSS patients compared with controls. There was no difference between the mean baseline FBF in JSS patients compared with patients with PRP. There was a significant decrease in FBF 1 min after CS in all groups followed by blood flow recovery at 20 min after CS in comparison with basal FBF values in controls, but not in JSS and PRP patients. CONCLUSION: In JSS patients, LDI showed a lower FBF before and after CS compared with healthy controls and may be an objective and sensitive method for the measurement of digital skin blood flow in RP children.