Doppler System Research Articles

Therapeutic effect of Cnidium officinale Makino extract on ovariectomized hind-limb ischemic mice

BackgroundCnidium officinale Makino (COM) has been used traditionally to treat female menstrual disorders, such as amenorrhea, hypomenorrhea and oligomenorrhea, by improving blood circulation. The present study aimed to investigate the alleviating effect of COM extracts on surgical injuryinduced ischemia in the hind-limb of mice. MethodsIn this study, female C57BL/6 mice were ovariectomized, and the vessels of the hind-limb were excised after ligation by surgical silk (6–0). The mice were orally administered with COM (150 or 300mg/kg/day) for 3 weeks, and the blood flow rate of hind-limbs was evaluated by using a laser Doppler system after hind-limb ischemic surgery in an in vivo study. Additionally, the migration and tube formation of human umbilical vein endothelial cells (HUVECs) were evaluated in an in vitro study. ResultsThe blood flow rate was synchronized to the nonischemic lesion of the hind-limb, and its elevation compared to the vehicle was observed at 14 and 21 days after hind-limb ischemic surgery in COM-treated groups. The number of capillaries increase in a dose-dependent manner in the COM-treated groups (150 and 300mg/kg). In HUVECs, the activities of cell migration were significantly increased by 50 and 75μg/mL for the COM-treated groups. In addition, the number of tubule branches and junctions was also increased by doses of COM (50 and/or 75μg/mL). ConclusionThe results of our study suggested that the COM extract may have therapeutic application for the treatment of hind-limb ischemic damage, which is due to the improvement of the peripheral angiogenetic system.

Switching Power Suppliers Noise Reduction in Ultrasound Doppler Fluid Measurements

Ultrasound Doppler techniques are widely employed in detecting the velocity of moving fluids both in medical and industrial applications. Echo Doppler electronics systems include a highly sensitive front-end suitable to processing the very low power ultrasound echoes received by the transducer. Moreover, the front-end input bandwidth typically ranges between 100 kHz and 10 MHz, which is the same frequency range where modern switching regulators work. Thus, the front-end is particularly prone to the noise produced by the suppliers that power the board itself. Electromagnetic interference (EMI) filters and spread-spectrum modulation of the switching regulator frequency help, but the results are often not optimal, and unacceptable artifacts are visible in the Doppler spectrum. In this paper a spread-spectrum modulation is proposed that concentrates the switching noise in the low-frequency range of the Doppler spectrum (e.g., 0–100 Hz). This range is removed by the high-pass clutter filter normally used in velocity Doppler investigations, thus switching noise and artifacts are eliminated. The method is verified through mathematical simulations and tested in measurements carried out with a research Doppler system. An example is presented in which the artifacts present during the investigation of a 0.4-m/s flow in a 25.4-mm diameter pipe are effectively removed by the proposed method.

Ameliorating effects of Cuscuta chinensis Lamak extract on hind‑limb ischemia, and angiogenic‑ or inflammatory associated factors in ovariectomized mice.

Cuscutachinensis Lamak (CCL) has traditionally been used in Korea to treat sexual disorders and skin problems. The aim of the present study was to investigate the effects of CCL extract on surgical injury‑induced ischemia in the hind limbs of mice. Specifically, female C57BL/6 mice were ovariectomized, and their hind‑limb vessels were ligated with surgical silk (6‑0) and excised. CCL (150or450mg/kg/BW) was then administered to the mice for 3weeks, and the blood flow rate was evaluated using a laser Doppler system at ‑7,0,7,14 and21days following hind‑limb ischemia. The serum expression profiles of angiogenic and inflammatory mediators were measured using an antibody array, and the transcript levels were reverse transcription‑quantitative polymerase chain reaction. The rate of hind limb blood flow was normalized to non‑ischemic lesions and revealed to be markedly elevated at 14 and 21days following ischemia when compared with the vehicle group. The density of capillaries in the hind limbs was also significantly increased following treatment with CCL in a dose‑dependent manner. In addition, the transcriptional expression of angiogenetic factors were upregulated, whereas that of inflammatory cytokines were downregulated. Finally, vascular endothelial cell migration and tube formation were evaluated invitro using human umbilical vein endothelial cells (HUVECs) and identified to be significantly increased following treatment with CCL. Overall, the results of the present study indicate that CCL extract exhibits therapeutic potential for the treatment of hind‑limb ischemia as it promotes peripheral angiogenic and anti‑inflammatory effects in mice.

Comparative Evaluation of Snowfall Retrievals from the CloudSat W-band Radar Using Ground-Based Weather Radars

AbstractInstantaneous liquid-equivalent snowfall rates S retrieved from CloudSat W-band cloud radar reflectivity Ze measurements are compared to estimates of S from operational Weather Surveillance Radar-1988 Doppler (WSR-88D) systems when the CloudSat satellite overflew the ground-based radar sites during spatially extensive nimbostratus snowfall events. For these comparisons, the ground-based radar measurements are interpolated to closely match in space and time spaceborne radar resolution volumes above ground clutter, thus avoiding uncertainties in deriving near-surface snowfall rates from measurements aloft by both radar types. Although typical uncertainties of both ground-based and spaceborne snowfall-rate retrieval approaches are quite high, the results from the standard optimal estimation CloudSat 2C-SNOW-PROFILE algorithm are on average in good agreement with the WSR-88D default snowfall algorithm results with correlation coefficients being around 0.8–0.85. The CloudSat standard optimal estimation snowfall-rate products are also shown to be in satisfactory agreement with retrievals from several simple W-band Ze–S relations suggested earlier. The snowfall rate and snow/ice water content (IWC) parameters from the CloudSat 2C-SNOW-PROFILE algorithm are highly interdependent. A tight relation between S and IWC is apparently introduced through the ice particle fall velocity assumption that is made in the reflectivity-based snowfall retrieval algorithm. This suggests that ice sedimentation rate estimates can also be deduced from applications of numerous empirical IWC–reflectivity relations derived previously for different cloud conditions when appropriate assumptions about fall velocities are made. Intercomparisons between different CloudSat snow/ice water content products indicated significant discrepancies in IWC values from different standard CloudSat retrieval algorithms.

Horizontal oil-water two-phase dispersed flow velocity profile study by ultrasonic doppler method

Flow velocity is an important parameter in oil-water two-phase flow, which is closely related to the oil production estimation and production safety. In recent years, pulse-wave Doppler is widely studied because it can obtain the velocity profile along the ultrasound beam. In this paper, a new Pulse-wave Doppler system based on the industrial bus was designed to measure the velocity profile of oil-water two-phase flow. This system was used to study the velocity profile of a horizontal tube oil-water two-phase flow, the flow patterns include dispersion of oil in water and water (Do/w & w), oil in water emulsion (O/W), dual dispersions of water in oil and oil in water (Dw/o & Do/w) and water in oil emulsion (W/O). The velocity profile obtained was compared with the Laser Doppler Velocimetry (LDV) data under similar flow conditions. The results showed that, in water continuous flow patterns, the velocity profile of the two-phase flow can be described by a modified Nikuradse equation that describes the velocity profile of single phase pipe flow; in oil continuous flow patterns, the velocity profile also can be described by a modified Nikuradse equation with different parameters.

Acupuncture and Acupressure Applied on the Extra-1 (Yintang) Acupoint in Healthy Volunteers Do Not Affect Regional Cerebral Blood Flow as Assessed by the Pulsatility Index: A Cohort Observational Study.

Objective: Acupressure applied on the Extra-1 (Yintang) point decreases bispectral index (BIS) values and stress in healthy volunteers. The current authors hypothesized that acupressure and/or acupuncture could alter regional cerebral oxygenation as expressed by middle cerebral-artery velocity. This study was conducted to test that hypothesis. Materials and Methods: After giving written informed consent, healthy volunteers received, randomly, (1) acupressure on the Extra-1 (Yintang) point, (2) acupressure on a sham point lying 2 cm over the lateral end of the right eyebrow, (3) no acupressure, or (4) modified manual acupuncture on the Extra-1 (Yintang) point. Each intervention lasted 10 minutes, except for acupuncture, which lasted for 20 minutes. The flow velocity of the left middle cerebral artery-as expressed by the Pulsatility Index (PI), heart rate (HR), and hemoglobin oxygen saturation (SpO2)-was recorded before each intervention, every 2 minutes during the intervention, and 10 and 70 minutes after the end of the intervention. A 2-MHz hand-held probe of a transcranial Doppler system (Companion II Micro TCD Nikolet Biomedical Inc., Madison, WI) was used to isolate the left middle cerebral artery via a transtemporal approach. Results: There was no difference among the four interventions at any timepoint in PI (P = 0.431; F = 0.929), HR (P = 0.948; F = 0.121), and SpO2 (P = 0.708; F = 0.465), as well as in systolic arterial pressure (P = 0.857; F = 0.255) or diastolic arterial pressure (P = 0.991; F = 0.036). Conclusions: There were no changes in PI measurements when acupuncture or acupressure was applied on the Extra-1 (Yintang) point once and for a limited time duration.

A double Paul trap system for the electronic coupling of ions

We report on the progress towards the implementation of a double trap system for the coupling of ion clouds stored in different traps through the charges they induce in a common electrode. The two traps have cylindrical symmetry and can be used either as Penning or Paul traps. The laser system for Doppler cooling of 40Ca+ clouds is described. The cooling can be performed differentially in the two traps, aiming at the study of the coupling between two clouds of ions at different temperatures. This setup is the starting point for the realization of energy transfer between two Doppler-cooled ions stored in different traps. We report on the status of the experiment and evaluate the performance required for an efficient coupling.

Coronary Artery Disease Severity Is Associated With Abdominal Aortic Intima-Media Thickness in Patients With Non-ST-Segment Elevation Myocardial Infarction.

The aim of this study was to evaluate the relationship between aortic intima-media thickness (aIMT) and coronary artery disease (CAD) severity in patients with non-ST-segment elevation myocardial infarction (NSTEMI). SYNTAX score (SS) was calculated. Patients were categorized into 2 main groups according to the SS: patient with high risk (SS ≥ 13) and low risk (SS < 13). Common carotid artery IMT (cIMT), common femoral artery IMT, and aIMT were measured with a high-resolution ultrasound Doppler system. We had 147 (52.9%) patients in the high-risk group and 132 patients in the low-risk group. Both cIMT and aIMT were significantly increased, and left ventricular ejection fraction (LVEF) was significantly lower in the high-risk group; aIMT (odds ratio [OR]: 1.272, P < .001), cIMT (OR: 1.239, P = .009), and LVEF (OR: 0.931, P = .002) were determined as independent predictors for the high-risk group. When the cutoff value was accepted as 1.25 mm for the aIMT, patients with high SS identification had 74.1% sensitivity and 89.4% specificity (area under the curve: 0.764, P < .001). In conclusion, aIMT detected by abdominal B-mode ultrasonography is closely associated with CAD severity in patients with NSTEMI.

Abstract 269: RBM20 Knockout Ameliorates Angiotensin II Induced Hypertension and Cardiac Hypertrophy

Introduction: RNA binding motif 20 (RBM20) is a muscle specific splicing factor that has been implicated in heart failure (HF). RBM20 regulates mRNA splicing of titin, a giant muscle protein that is expressed in cardiac and smooth muscles and plays a major role in passive stiffness of them. RBM20 knockout (KO) results in less myocardial stiffness by inducing large titin isoform expression. Hence, we hypothesize that RBM20 decreases arterial stiffness through large titin isoform expression, and thus reduces blood pressure (BP) in hypertension. The aim of this study was to investigate whether RBM20 could be a therapeutic target to reduce BP in patients with hypertension and prevent HF progression. Methods: Male wild type (WT) (Sprague-Dawley х Brown Norway) and Rbm20 KO rats (n=10 each) were subcutaneously implanted with osmotic mini-pump to continuously release angiotensin II (Ang II) at a rate of 400 ng/kg/min for 28 days. BP was measured by noninvasive tail-cuff system weekly. Pulse wave velocity (PWV) was measured by Doppler system. Cardiac remodeling was evaluated by echocardiography. Biochemistry and histological analyses were performed on aorta and heart tissues. Results: Larger titin isoform was increased and no difference of elastin and collagen expression was observed in RBM20 KO blood vessels when compared to WT. Basal BPs were the same in WT and KO rats (diastolic BP, KO 91.75 ± 1.83 vs. WT 94.33±1.88 mmHg; systolic BP, KO 127.6 ± 0.97 vs. WT 128.0 ± 1.35 mmHg). Ang II increased BP in both WT and KO rats, but KO had a significantly lower BP than WT (diastolic BP, KO 141.7 ± 5.00 vs. WT 182.0±4.84 mmHg; systolic BP, KO 195.4 ± 3.671 vs. WT 226.4 ± 3.093 mmHg, P&lt;0.0001). PWV is lower in KO rats than in WT (KO 4.035 ± 0.21 mm/s vs. WT 5.128±0.37 mm/s, P&lt;0.05). Cardiac hypertrophy was developed in both WT and KO hearts treated with Ang II, but it was alleviated in the KO heart (left ventricular wall, KO 0.324 ± 0.01 cm vs. WT 0.368 ± 0.013 cm, P&lt;0.05). Conclusions: RBM20 KO reduces arterial stiffness through increased larger titin isoform expression, decreases Ang II-induced hypertension, and prevents HF progression. These findings suggest that RBM20 could be a potential novel target for the treatment of hypertension and hypertension-induced cardiac hypertrophy.

Enucleation of schwannoma of the penis with neurovascular bundle sparing using the VTI 20 MHz Microvascular Doppler System

A 48-year-old man had an unremarkable past medical history. His current illness began 8 years prior to medical consultation with a non-painful, progressive increase in volume at the base of the penis in the dorsal region. The patient had adequate erections but was unable to perform coitus due to the presence of a mass. He complained of no other symptomatology. Physical examination revealed an uncircumcised cylindrical penis and a central meatus. A non-painful, mobile, stony hard tumor measuring approximately 6 cm × 5 cm was located at the dorsal region of the base of the penis. It was not fixed to the deep planes and there were no color changes. MRI of the penis identified a round, solid, well-circumscribed tumor with a heterogeneous content and extremely vascularized aspect. It was not dependent on the corpora cavernosa but caused compression and displacement to the left. The penile tumor was completely extirpated using the VTI 20 MHz Microvascular Doppler System, sparing the neurovascular bundles. The histopathologic report and immunohistochemistry study confirmed the diagnosis of Schwannoma of the penis. At follow-up at more than two years, the patient has no signs of tumor activity and erections are adequate.

Clutter and Range Ambiguity Suppression Using Diverse Pulse Train in Pulse Doppler System.

Pulse Doppler (PD) systems are widely used for moving target detection, especially in scenarios with clutter. Range ambiguity, which arises from fixed parameters in waveforms, is an inherent drawback in conventional systems. By using a diverse pulse train such as a train of coherent diverse phase coded pulses, these ambiguous peaks can be suppressed effectively but at the cost of sidelobe dispersions. In this work, a novel efficient PD process is proposed to suppress range ambiguity and detect moving targets under strong clutter. Poly-phase coded pulses are employed along with optimal receiving filters, by which the dispersed sidelobes are mitigated to a great extent. Moreover, a novel clutter suppression procedure is included in the PD process, by which strong clutter can be greatly suppressed. Well-designed receiving and inverse filters are employed. Simulation examples are presented to verify the theories. Compared with conventional methods, much better detection results are obtained for both near and remote targets, especially in scenarios with strong clutter.

Pulsed wave–doppler ultrasonographic evaluation of mammary blood flows speed in cows during different productive periods

Circulatory phenomena are complex organic functions that depend on several factors as blood viscosity, vascular walls elasticity, cardiac pump rhythm, discontinuous activity, various resistance to blood flow in tissues and spontaneous or induced vasomotor responses. Doppler ultrasonographic method is a valid tool for performing mammary blood flow recordings. Seven Bruna Italiana cows (average age 5 years) during 3 different period of lactation (40, 100, 210 days after the delivery) and during the dry period (290 days after the delivery) were used for our study. Systolic and diastolic flow speeds recordings of right and left external pudendal arteries (before the cranial and the caudal mammary bifurcation) were carried out on each subjects by means of a Pulsed Doppler System. By appliyng repeated measures ANOVA between the different lactation phases and the dry period systolic and diastolic blood flows both for right and left external pudendal artery showed the same pattern. The systolic speed of right and left external pudendal arteries showed the following statistical significances: systolic speed before milking (F (3,18) =37.71; P (3,18) =30.91; P (3,18) = 52.94; P (3,18) =32.49; P (3,18) =19.89; P (3,18) =24.09; P (3,18) =36.75; P (3,18) =41.56; P

Doppler coherence imaging of divertor and SOL flows in ASDEX upgrade and Wendelstein 7-X

Measurement of ion dynamics is of great importance to the study of plasma exhaust and impurity particle flows in the scrape-off-layer (SOL) and divertor in magnetic confinement experiments. Doppler coherence imaging spectroscopy (CIS) is a passive optical diagnostic that produces 2D images of line-integrated ion flow velocity. Doppler CIS flow measurements of neutral deuterium and impurities were conducted for the first time in the divertor of the medium-sized tokamak experiment ASDEX Upgrade. A detailed sightline, emission and magnetic field analysis was undertaken to identify location and direction of flows. Under the assumption of toroidal axisymmetry, they revealed mainly parallel impurity flows in the proximity of the X-point and target plates on the order of 20 km s−1. Two Doppler CIS systems are currently set up for the optimized stellarator Wendelstein 7-X (W7-X). The main task of this diagnostic will be the measurement of impurity ion flows in one of the island divertors of W7-X. EMC3-EIRENE simulations have been carried out to estimate the flow behaviour in the W7-X SOL.

Evaluation of Examiner Performance Using a Duplex Ultrasound Simulator. Flow Velocity Measurements in Dialysis Access Fistula Models

We developed a duplex ultrasound simulator for training and assessment of scanning skills. We used the simulator to test examiner performance in the measurement of flow velocities in dialysis access fistulas. Test cases were created from 3-D ultrasound scans of two dialysis access fistulas by reconstructing 3-D blood vessel models and simulating blood flow velocity fields within the lumens. The simulator displays a 2-D B-mode or color Doppler image corresponding to transducer position on a mannequin; a spectral waveform is generated according to Doppler sample volume location and system settings. Examiner performance was assessed by comparing the measured peak systolic velocity (PSV) with the true PSV provided by the computational flow model. The PSV measured by four expert examiners deviated from the true value by 7.8 ± 6.1%. The results indicate the ability of the simulator to objectively assess an examiner's measurement accuracy in complex vascular targets.

Estimating Ocean Vector Winds and Currents Using a Ka-Band Pencil-Beam Doppler Scatterometer

Ocean surface currents and winds are tightly coupled essential climate variables, and, given their short time scales, observing them at the same time and resolution is of great interest. DopplerScatt is an airborne Ka-band scatterometer that has been developed under NASA’s Instrument Incubator Program (IIP) to provide a proof of concept of the feasability of measuring these variables using pencil-beam scanning Doppler scatterometry. In the first half of this paper, we present the Doppler scatterometer measurement and processing principles, paying particular attention to deriving a complete measurement error budget. Although Doppler radars have been used for the estimation of surface currents, pencil-beam Doppler Scatterometry offers challenges and opportunities that require separate treatment. The calibration of the Doppler measurement to remove platform and instrument biases has been a traditional challenge for Doppler systems, and we introduce several new techniques to mitigate these errors when conical scanning is used. The use of Ka-band for airborne Doppler scatterometry measurements is also new, and, in the second half of the paper, we examine the phenomenology of the mapping from radar cross section and radial velocity measurements to winds and surface currents. To this end, we present new Ka-band Geophysical Model Functions (GMFs) for winds and surface currents obtained from multiple airborne campaigns. We find that the wind Ka-band GMF exhibits similar dependence on wind speed as that for Ku-band scatterometers, such as QuikSCAT, albeit with much greater upwind-crosswind modulation. The surface current GMF at Ka-band is significantly different from that at C-band, and, above 4.5 m/s has a weak dependence on wind speed, although still dependent on wind direction. We examine the effects of Bragg-wave modulation by long waves through a Modululation Transfer Function (MTF), and show that the observed surface current dependence on winds is consistent with past Ka-band MTF observations. Finally, we provide a preliminary validation of our geophysical retrievals, which will be expanded in subsequent publications. Our results indicate that Ka-band Doppler scatterometry could be a feasible method for wide-swath simultaneous measurements of winds and currents from space.

Russian-Cuban Colocation Station for Radio Astronomical Observation and Monitoring of Near-Earth Space

The article presents the main possibilities of using the projected Russian-Cuban geodynamic colocation station on the basis of the Institute of Geophysics and Astronomy of the Ministry of Science, Technology and the Environment of the Republic of Cuba to carry out radio observations and monitoring the near-Earth space. Potential capabilities of the station are considered for providing various observational programs: astrophysical observations; observations by space geodesy methods using radio very long baselines interferometers, global navigation satellite systems, laser rangers, and various Doppler systems, as well as monitoring of artificial and natural bodies in the near-Earth and deep space, including the ranging of asteroids approaching the Earth. The results of modeling the observations on the planned station are compared with that obtained on the existing geodynamic stations. The efficiency of the projected Russian-Cuban station for solving astronomical tasks is considered.

Cerebral microembolism in the critically ill with acute kidney injury (COMET-AKI trial): study protocol for a randomized controlled clinical trial

BackgroundMicroembolism is a frequent pathological event during extracorporeal renal replacement therapy (RRT). Some previous data indicate that microemboli are generated in patients who are undergoing RRT and that these may contribute to increased cerebrovascular and neurocognitive morbidity in patients with end-stage renal disease. The current trial aims to quantify the microembolic load and respective qualitative composition that effectively reaches the intracerebral circulation in critically ill patients treated with different RRT modalities for acute kidney injury (AKI).Methods/designThe COMET-AKI trial is a prospective, randomized controlled clinical trial with a 2-day clinical assessment period and follow-up visits at 6 and 12 months. Consecutive critically ill patients with AKI on continuous renal replacement therapy (CRRT) scheduled for a switch to intermittent renal replacement therapy (IRRT) will be randomized to either switch to IRRT within the next 24 h or continued CRRT for an additional 24 h. Cerebral microembolic load will be determined at baseline, i.e., before switch (on CRRT for both groups) and on IRRT versus CRRT, whichever group they were randomized to. The primary endpoint is defined as the difference in mean total cerebral microemboli count during the measurement period on CRRT versus IRRT following randomization. Microemboli will be assessed within the RRT circuit by a 1.5-MHz ultrasound detector attached to the venous RRT tubing and cerebral microemboli will be measured in the middle cerebral artery using a 1.6-MHz robotic transcranial Doppler system with automatic classification of Doppler signals as solid or gaseous. In addition to Doppler measurements, patients will be examined by magnetic resonance imaging and neurocognitive tests to gain better understanding into the potential morphological and clinical consequences of embolization.DiscussionThe results of COMET-AKI may help to gain a better insight into RRT modality-associated differences regarding microbubble generation and the cerebral microembolic burden endured by RRT recipients. Furthermore, identification of covariates of microbubble formation and distribution may help to encourage the evolution of next-generation RRT circuits including machinery and/or filters.Trial registrationClinicalTrials.gov, ID: NCT02621749. Registered on 3 December 2015.

Satellite-Link Attenuation Measurement Technique for Estimating Rainfall Accumulation

A technique using satellite-link signal attenuation measurements for estimating rainfall accumulation along the link path is evaluated. Power law relationships between attenuation rate $A$ and rainfall rate $R$ are used to estimate $R$ and rainfall accumulation with a satellite link operating at Ku-band (12.3 GHz). Polarimetric radar measurements obtained from a National Weather Service Weather Surveillance Radar—1988 Doppler system near State College, Pennsylvania, are utilized to provide a comparison of rainfall accumulation estimates. A tipping-bucket rain gauge, colocated with the satellite receiver, is also used for comparison. A method based on bit error ratio measurements for the satellite link is used to identify periods of rain during which the rainfall rate is estimated from signal attenuation measurements. The effective rain height used in converting the attenuation rate along the link path into the rainfall rate is estimated from polarimetric radar observations. The Ku-band link is not very sensitive to light rain below 1.5 mm/h. Rainfall accumulation estimates obtained for 11 different days using satellite link attenuation show good comparisons with radar (within 19%) for accumulations greater than 6 mm and not so good (within 43%) for accumulations below 3 mm. The results presented in this paper show that using satellite-link attenuation measurements to estimate rainfall accumulations is a promising technique that requires further testing and refinement.

"Internet of Things" Real-Time Free Flap Monitoring.

Free flaps are a common treatment option for head and neck reconstruction in plastic reconstructive surgery, and monitoring of the free flap is the most important factor for flap survival. In this study, the authors performed real-time free flap monitoring based on an implanted Doppler system and "internet of things" (IoT)/wireless Wi-Fi, which is a convenient, accurate, and efficient approach for surgeons to monitor a free flap. Implanted Doppler signals were checked continuously until the patient was discharged by the surgeon and residents using their own cellular phone or personal computer. If the surgeon decided that a revision procedure or exploration was required, the authors checked the consumed time (positive signal-to-operating room time) from the first notification when the flap's status was questioned to the determination for revision surgery according to a chart review. To compare the efficacy of real-time monitoring, the authors paired the same number of free flaps performed by the same surgeon and monitored the flaps using conventional methods such as a physical examination. The total survival rate was greater in the real-time monitoring group (94.7% versus 89.5%). The average time for the real-time monitoring group was shorter than that for the conventional group (65 minutes versus 86 minutes). Based on this study, real-time free flap monitoring using IoT technology is a method that surgeon and reconstruction team can monitor simultaneously at any time in any situation.

Detection of Flow Obstruction in Peripheral Arteries by Primary Care Providers: A Population-Based Registry Study

Peripheral arterial disease (PAD) is a condition with serious comorbidities and mortality that is frequently under-diagnosed because it is not typically associated with the classic symptoms of claudication. In primary care settings, measurement of the ankle-brachial index (ABI) with pressure cuff Doppler systems is problematic due to the necessity of a vascular technician, the time required to perform the test, and the cost of a specialized vascular diagnostic unit or laboratory facility. One cost-effective approach that has been studied to identify PAD is to use a blood volume plethysmography system (VPS) at the point of care. Quantitative VPS gives primary care physicians and other clinicians a PAD test for use in the office setting that is practical in terms of time and cost and is operator independent. This paper reports on the use of VPS in a registry of 226,565 patients presenting to participating primary care practices in the United States. All patients were given a standardized, self-administered questionnaire to identify PAD symptoms and cardiovascular risk factors either in clinic or at home. Patients who met the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for screening for PAD were then tested with VPS for assessing flow obstruction in the lower extremities. Of the 226,565 patients registered, results showed 70,651 (31.3%) had moderate to severe flow impairment. The subset analysis of 27,079 patients for whom more detailed severity data was available showed 70.0% had no to mild flow disturbance, 17.2% had moderate flow obstruction, 7.9% had significant flow impairment and 4.9% had severe flow abnormalities. The registry study showed that clinical symptoms were unreliable in being able to discriminate disease from no disease. Earlier recognition of PAD might lead to earlier secondary preventive measures and improved outcomes for a population with documented high risk of cardiovascular morbidity and mortality.