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1.
Biomed Eng Online ; 20(1): 31, 2021 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-33766046

RESUMO

INTRODUCTION: The use of machine learning (ML) methods would improve the diagnosis of respiratory changes in systemic sclerosis (SSc). This paper evaluates the performance of several ML algorithms associated with the respiratory oscillometry analysis to aid in the diagnostic of respiratory changes in SSc. We also find out the best configuration for this task. METHODS: Oscillometric and spirometric exams were performed in 82 individuals, including controls (n = 30) and patients with systemic sclerosis with normal (n = 22) and abnormal (n = 30) spirometry. Multiple instance classifiers and different supervised machine learning techniques were investigated, including k-Nearest Neighbors (KNN), Random Forests (RF), AdaBoost with decision trees (ADAB), and Extreme Gradient Boosting (XGB). RESULTS AND DISCUSSION: The first experiment of this study showed that the best oscillometric parameter (BOP) was dynamic compliance, which provided moderate accuracy (AUC = 0.77) in the scenario control group versus patients with sclerosis and normal spirometry (CGvsPSNS). In the scenario control group versus patients with sclerosis and altered spirometry (CGvsPSAS), the BOP obtained high accuracy (AUC = 0.94). In the second experiment, the ML techniques were used. In CGvsPSNS, KNN achieved the best result (AUC = 0.90), significantly improving the accuracy in comparison with the BOP (p < 0.01), while in CGvsPSAS, RF obtained the best results (AUC = 0.97), also significantly improving the diagnostic accuracy (p < 0.05). In the third, fourth, fifth, and sixth experiments, different feature selection techniques allowed us to spot the best oscillometric parameters. They resulted in a small increase in diagnostic accuracy in CGvsPSNS (respectively, 0.87, 0.86, 0.82, and 0.84), while in the CGvsPSAS, the best classifier's performance remained the same (AUC = 0.97). CONCLUSIONS: Oscillometric principles combined with machine learning algorithms provide a new method for diagnosing respiratory changes in patients with systemic sclerosis. The present study's findings provide evidence that this combination may help in the early diagnosis of respiratory changes in these patients.


Assuntos
Diagnóstico por Computador , Aprendizado de Máquina , Oscilometria , Transtornos Respiratórios/complicações , Transtornos Respiratórios/diagnóstico , Escleroderma Sistêmico/complicações , Escleroderma Sistêmico/diagnóstico , Adolescente , Adulto , Idoso , Algoritmos , Inteligência Artificial , Biometria , Computadores , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Espirometria , Adulto Jovem
2.
High Blood Press Cardiovasc Prev ; 28(2): 185-249, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33620672

RESUMO

INTRODUCTION: Systolic blood pressure (SBPA) and pulse pressure amplification (PPA) were quantified using different methodological and calibration approaches to analyze (1) the association and agreement between different SBPA and PPA parameters and (2) the association between these SBPA and PPA parameters and left ventricle (LV) and atrium (LA) structural and functional characteristics. METHODS: In 269 healthy subjects, LV and LA parameters were echocardiography-derived. SBPA and PPA parameters were quantified using: (1) different equations (n = 9), (2) methodological approaches (n = 3): brachial sub-diastolic (Mobil-O-Graph®) and supra-systolic oscillometry (Arteriograph®) and aortic diameter waveform re-calibration (RCD; ultrasonography), and (3) using three different calibration schemes: systo-diastolic (SD), calculated mean (CM) and oscillometric mean (OscM). RESULTS: SBPA and PPA parameters obtained with different equations, techniques, and calibration schemes show a highly variable association level (negative, non-significant, and/or positive) among them. The association between SBPA and PPA with cardiac parameters were highly variable (negative, non-significant, or positive associations). Differences in BPA parameter data between approaches were more sensitive to the calibration method than to the device used. Both, SBPA and PPA obtained with brachial sub-diastolic technique and calibrated to CM or OscM showed higher levels of association with LV and LA structural characteristics. CONCLUSIONS: Our data show that many of the parameters that assume to quantify the same phenomenon of BPA are not related to each other in the different age groups. Both, SBPA and PPA obtained with brachial sub-diastolic technique and calibrated to CM or OscM showed higher levels of association with LV and LA structural characteristics.


Assuntos
Função do Átrio Esquerdo , Determinação da Pressão Arterial/normas , Pressão Sanguínea , Coração/fisiologia , Função Ventricular Esquerda , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Determinação da Pressão Arterial/instrumentação , Calibragem , Criança , Estudos Transversais , Ecocardiografia Doppler , Feminino , Voluntários Saudáveis , Coração/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Oscilometria , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Adulto Jovem
3.
Anesthesiology ; 134(2): 179-188, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33326001

RESUMO

BACKGROUND: The optimal method for blood pressure monitoring in obese surgical patients remains unknown. Arterial catheters can cause potential complications, and noninvasive oscillometry provides only intermittent values. Finger cuff methods allow continuous noninvasive monitoring. The authors tested the hypothesis that the agreement between finger cuff and intraarterial measurements is better than the agreement between oscillometric and intraarterial measurements. METHODS: This prospective study compared intraarterial (reference method), finger cuff, and oscillometric (upper arm, forearm, and lower leg) blood pressure measurements in 90 obese patients having bariatric surgery using Bland-Altman analysis, four-quadrant plot and concordance analysis (to assess the ability of monitoring methods to follow blood pressure changes), and error grid analysis (to describe the clinical relevance of measurement differences). RESULTS: The difference (mean ± SD) between finger cuff and intraarterial measurements was -1 mmHg (± 11 mmHg) for mean arterial pressure, -7 mmHg (± 14 mmHg) for systolic blood pressure, and 0 mmHg (± 11 mmHg) for diastolic blood pressure. Concordance between changes in finger cuff and intraarterial measurements was 88% (mean arterial pressure), 85% (systolic blood pressure), and 81% (diastolic blood pressure). In error grid analysis comparing finger cuff and intraarterial measurements, the proportions of measurements in risk zones A to E were 77.1%, 21.6%, 0.9%, 0.4%, and 0.0% for mean arterial pressure, respectively, and 89.5%, 9.8%, 0.2%, 0.4%, and 0.2%, respectively, for systolic blood pressure. For mean arterial pressure and diastolic blood pressure, absolute agreement and trending agreement between finger cuff and intraarterial measurements were better than between oscillometric (at each of the three measurement sites) and intraarterial measurements. Forearm performed better than upper arm and lower leg monitoring with regard to absolute agreement and trending agreement with intraarterial monitoring. CONCLUSIONS: The agreement between finger cuff and intraarterial measurements was better than the agreement between oscillometric and intraarterial measurements for mean arterial pressure and diastolic blood pressure in obese patients during surgery. Forearm oscillometry exhibits better measurement performance than upper arm or lower leg oscillometry.


Assuntos
Cirurgia Bariátrica , Determinação da Pressão Arterial/métodos , Monitorização Intraoperatória/métodos , Obesidade/cirurgia , Pressão Sanguínea , Determinação da Pressão Arterial/estatística & dados numéricos , Cateterismo Periférico/métodos , Cateterismo Periférico/estatística & dados numéricos , Feminino , Dedos , Humanos , Masculino , Pessoa de Meia-Idade , Oscilometria/métodos , Oscilometria/estatística & dados numéricos , Estudos Prospectivos , Reprodutibilidade dos Testes
4.
PLoS Comput Biol ; 16(12): e1008485, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33338032

RESUMO

The increased democratization of the creation, implementation, and attendance of academic conferences has been a serendipitous benefit of the movement toward virtual meetings. The Coronavirus Disease 2019 (COVID-19) pandemic has accelerated the transition to online conferences and, in parallel, their democratization, by necessity. This manifests not just in the mitigation of barriers to attending traditional physical conferences but also in the presentation of new, and more importantly attainable, opportunities for young scientists to carve out a niche in the landscape of academic meetings. Here, we describe an early "proof of principle" of this democratizing power via our experience organizing the Canadian Computational Neuroscience Spotlight (CCNS; crowdcast.io/e/CCNS), a free 2-day virtual meeting that was built entirely amid the pandemic using only virtual tools. While our experience was unique considering the obstacles faced in creating a conference during a pandemic, this was not the only factor differentiating both our experience and the resulting meeting from other contemporary online conferences. Specifically, CCNS was crafted entirely by early career researchers (ECRs) without any sponsors or partners, advertised primarily using social media and "word of mouth," and designed specifically to highlight and engage trainees. From this experience, we have distilled "10 simple rules" as a blueprint for the design of new virtual academic meetings, especially in the absence of institutional support or partnerships, in this unprecedented environment. By highlighting the lessons learned in implementing our meeting under these arduous circumstances, we hope to encourage other young scientists to embrace this challenge, which would serve as a critical next step in further democratizing academic meetings.


Assuntos
Neurociências/educação , Neurociências/tendências , Mídias Sociais , Telecomunicações , Encéfalo/patologia , Canadá , Biologia Computacional , Congressos como Assunto , Humanos , Cooperação Internacional , Internet , Oscilometria , Pandemias , Universidades
5.
Anesthesiology ; 133(5): 997-1006, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-33048167

RESUMO

BACKGROUND: In most patients having noncardiac surgery, blood pressure is measured with the oscillometric upper arm cuff method. Although the method is noninvasive and practical, it is known to overestimate intraarterial pressure in hypotension and to underestimate it in hypertension. A high-fidelity upper arm cuff incorporating a hydraulic sensor pad was recently developed. The aim of the present study was to investigate whether noninvasive blood pressure measurements with the new high-fidelity cuff correspond to invasive measurements with a femoral artery catheter, especially at low blood pressure. METHODS: Simultaneous measurements of blood pressure recorded from a femoral arterial catheter and from the high-fidelity upper arm cuff were compared in 110 patients having major abdominal surgery or neurosurgery. RESULTS: 550 pairs of blood pressure measurements (5 pairs per patient) were considered for analysis. For mean arterial pressure measurements, the average bias was 0 mmHg, and the precision was 3 mmHg. The Pearson correlation coefficient was 0.96 (P < 0.0001; 95% CI, 0.96 to 0.97), and the percentage error was 9%. Error grid analysis showed that the proportions of mean arterial pressure measurements done with the high-fidelity cuff method were 98.4% in zone A (no risk), 1.6% in zone B (low risk) and 0% in zones C, D, and E (moderate, significant, and dangerous risk, respectively). The high-fidelity cuff method detected mean arterial pressure values less than 65 mmHg with a sensitivity of 84% (95% CI, 74 to 92%) and a specificity of 97% (95% CI, 95% to 98%). To detect changes in mean arterial pressure of more than 5 mmHg, the concordance rate between the two methods was 99.7%. Comparable accuracy and precision were observed for systolic and diastolic blood pressure measurements. CONCLUSIONS: The new high-fidelity upper arm cuff method met the current international standards in terms of accuracy and precision. It was also very accurate to track changes in blood pressure and reliably detect severe hypotension during noncardiac surgery.


Assuntos
Pressão Arterial/fisiologia , Determinação da Pressão Arterial/métodos , Determinação da Pressão Arterial/normas , Monitorização Intraoperatória/métodos , Monitorização Intraoperatória/normas , Adulto , Idoso , Idoso de 80 Anos ou mais , Determinação da Pressão Arterial/instrumentação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Intraoperatória/instrumentação , Oscilometria/instrumentação , Oscilometria/métodos , Oscilometria/normas , Estudos Prospectivos , Adulto Jovem
6.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 469-472, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018029

RESUMO

Up until now estimation of arterial compliance has been performed either by analysis of arterial pressure changes with respect to volume changes or by inference based on pulse wave velocity (PWV). In this study we demonstrate the possibility of an approach to assess arterial compliance by fusing the two information sources namely the pressure/volume relationship obtained from oscillography and PWV data. The goal is to assess arterial properties easily and robustly, enhancing current hemodynamic monitoring. The approach requires as input signals: an electrocardiogram (ECG), a photo- plethysmogram (PPG) and the arterial oscillation as measured during non-invasive blood pressure measurements based on oscillometry with a cuff. These signals are fused by an algorithm using Bayesian principles underpinned by a physiological model. In our simulations, we demonstrate the feasibility to infer arterial compliance by our proposed strategy. A very first measurement on a healthy volunteer supports our findings from the simulation.Clinical Relevance- Arterial compliance/stiffness is recognized as a key hemodynamic parameter, which is not easily accessible and not a standard parameter currently. The presented method and obtained results are encouraging for future research in this area.


Assuntos
Artérias , Análise de Onda de Pulso , Teorema de Bayes , Complacência (Medida de Distensibilidade) , Humanos , Oscilometria
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 4996-4999, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33019108

RESUMO

This work presents a new technique for the noninvasive measurement of systolic blood pressure (sBP), mean blood pressure (mBP) and diastolic blood pressure (dBP) using photo-plethysmographic (PPG) sensors when an artery is exposed to an external pressure. Two sets of experiments were performed: a first study combining PPG with an oscillometric device and the second combining PPG with a force/pressure sensor. These two experiments enable the estimation of BP values. PPG results were found to be comparable to oscillometric results, with bias and precision errors of -0.81 and 5.26 for sBP, 1.12 and 5.61 for mBP and 1.67 and 9.09 for dBP (n = 28). Furthermore, amplification over the brachial-to-finger path was found to be 1.02 ± 0.08 for mBP (n = 20) confirming that mBP does not undergo any amplification along the arterial tree whereas, for sBP, an amplification of 1.20 ± 0.12 (n = 7) was found for green wavelength, 1.35 ± 0.09 (n = 6) for red wavelength and 1.36 ± 0.09 (n = 6) for infrared wavelength. Thus, amplification for sBP is bigger for red and infrared wavelengths compared to green one.


Assuntos
Pressão Arterial , Determinação da Pressão Arterial , Artérias , Pressão Sanguínea , Humanos , Oscilometria
8.
Anesth Analg ; 131(5): 1540-1550, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33079877

RESUMO

BACKGROUND: Continuous blood pressure monitoring may facilitate early detection and prompt treatment of hypotension. We tested the hypothesis that area under the curve (AUC) mean arterial pressure (MAP) <65 mm Hg is reduced by continuous invasive arterial pressure monitoring. METHODS: Adults having noncardiac surgery were randomly assigned to continuous invasive arterial pressure or intermittent oscillometric blood pressure monitoring. Arterial catheter pressures were recorded at 1-minute intervals; oscillometric pressures were typically recorded at 5-minute intervals. We estimated the arterial catheter effect on AUC-MAP <65 mm Hg using a multivariable proportional odds model adjusting for imbalanced baseline variables and duration of surgery. Pressures <65 mm Hg were categorized as 0, 1-17, 18-91, and >91 mm Hg × minutes of AUC-MAP <65 mm Hg (ie, no hypotension and 3 equally sized groups of increasing hypotension). RESULTS: One hundred fifty-two patients were randomly assigned to arterial catheter use and 154 to oscillometric monitoring. For various clinical reasons, 143 patients received an arterial catheter, while 163 were monitored oscillometrically. There were a median [Q1, Q3] of 246 [187, 308] pressure measurements in patients with arterial catheters versus 55 (46, 75) measurements in patients monitored oscillometrically. In the primary intent-to-treat analysis, catheter-based monitoring increased detection of AUC-MAP <65 mm Hg, with an estimated proportional odds ratio (ie, odds of being in a worse hypotension category) of 1.78 (95% confidence interval [CI], 1.18-2.70; P = .006). The result was robust over an as-treated analysis and for sensitivity analyses with thresholds of 60 and 70 mm Hg. CONCLUSIONS: Intraoperative blood pressure monitoring with arterial catheters detected nearly twice as much hypotension as oscillometric measurements.


Assuntos
Pressão Arterial , Cateteres , Hipotensão/diagnóstico , Complicações Intraoperatórias/diagnóstico , Monitorização Intraoperatória/métodos , Idoso , Área Sob a Curva , Diagnóstico Precoce , Feminino , Humanos , Hipotensão/terapia , Complicações Intraoperatórias/terapia , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Oscilometria , Sensibilidade e Especificidade , Procedimentos Cirúrgicos Operatórios , Resultado do Tratamento
9.
Phys Rev Lett ; 125(9): 094101, 2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32915595

RESUMO

Synchronization is a widespread phenomenon observed in physical, biological, and social networks, which persists even under the influence of strong noise. Previous research on oscillators subject to common noise has shown that noise can actually facilitate synchronization, as correlations in the dynamics can be inherited from the noise itself. However, in many spatially distributed networks, such as the mammalian circadian system, the noise that different oscillators experience can be effectively uncorrelated. Here, we show that uncorrelated noise can in fact enhance synchronization when the oscillators are coupled. Strikingly, our analysis also shows that uncorrelated noise can be more effective than common noise in enhancing synchronization. We first establish these results theoretically for phase and phase-amplitude oscillators subject to either or both additive and multiplicative noise. We then confirm the predictions through experiments on coupled electrochemical oscillators. Our findings suggest that uncorrelated noise can promote rather than inhibit coherence in natural systems and that the same effect can be harnessed in engineered systems.


Assuntos
Relógios Biológicos , Modelos Teóricos , Humanos , Oscilometria/métodos , Processos Estocásticos
10.
Eur J Vasc Endovasc Surg ; 60(3): 462-468, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32763120

RESUMO

OBJECTIVE: Ankle brachial index (ABI) is widely used for the diagnosis of lower extremity artery disease (LEAD). The purpose of this prospective study was to validate the diagnostic ability and reproducibility of a four cuff automated oscillometric device vs. the Doppler method. METHODS: Patients with suspected LEAD or asymptomatic individuals at risk because of the presence two or more cardiovascular risk factors were enrolled. For each patient, Doppler and oscillometric ABI measurements were repeated by two observers to address intra- and interobserver reproducibility. RESULTS: In total, 118 patients were evaluated. The prevalence of Doppler ABI (Dop-ABI) ≤ 0.90 was 45.8%. Taking the Dop-ABI as the reference, the sensitivity, specificity, accuracy, positive and negative predictive values of oscillometric ABI (Osc-ABI) during the first measurement by the first observer were 89.1%, 94.4%, 94.1%, 91.8%, and 92.4%, respectively. The concordance for diagnosing ABI ≤0.90 between methods was excellent (kappa coefficients ranging from 0.80 to 0.88 with different observers). Intra-observer reproducibility assessed by intraclass correlation coefficient (ICC) between methods were 0.94 for observer 1 and 0.96 for observer 2. The intra-observer reproducibility using the same method was also excellent (ICC 0.94, 95% confidence interval [CI] 0.91-0.95) for Dop-ABI and 0.95 (95% CI 0.93-0.97) for Osc-ABI). The ICC for interobserver reproducibility using the same method was 0.95 (95% CI 0.92-0.96) for Dop-ABI and 0.96 (95% CI 0.94-0.97) for Osc-ABI. CONCLUSION: This study validates the excellent diagnostic performances of a four cuff oscillometric device specifically designed for screening for LEAD. The simple measurement method could therefore be advocated in primary care where fast, easy, and reliable methods are suitable.


Assuntos
Índice Tornozelo-Braço/instrumentação , Extremidade Inferior/irrigação sanguínea , Oscilometria/instrumentação , Doença Arterial Periférica/diagnóstico , Ultrassonografia Doppler , Idoso , Idoso de 80 Anos ou mais , Desenho de Equipamento , Feminino , França , Humanos , Japão , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Doença Arterial Periférica/diagnóstico por imagem , Doença Arterial Periférica/fisiopatologia , Valor Preditivo dos Testes , Estudos Prospectivos , Reprodutibilidade dos Testes
11.
PLoS Comput Biol ; 16(7): e1008069, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32716940

RESUMO

Nitric oxide (NO) is a gaseous signaling molecule that plays an important role in neurovascular coupling. NO produced by neurons diffuses into the smooth muscle surrounding cerebral arterioles, driving vasodilation. However, the rate of NO degradation in hemoglobin is orders of magnitude higher than in brain tissue, though how this might impact NO signaling dynamics is not completely understood. We used simulations to investigate how the spatial and temporal patterns of NO generation and degradation impacted dilation of a penetrating arteriole in cortex. We found that the spatial location of NO production and the size of the vessel both played an important role in determining its responsiveness to NO. The much higher rate of NO degradation and scavenging of NO in the blood relative to the tissue drove emergent vascular dynamics. Large vasodilation events could be followed by post-stimulus constrictions driven by the increased degradation of NO by the blood, and vasomotion-like 0.1-0.3 Hz oscillations could also be generated. We found that these dynamics could be enhanced by elevation of free hemoglobin in the plasma, which occurs in diseases such as malaria and sickle cell anemia, or following blood transfusions. Finally, we show that changes in blood flow during hypoxia or hyperoxia could be explained by altered NO degradation in the parenchyma. Our simulations suggest that many common vascular dynamics may be emergent phenomena generated by NO degradation by the blood or parenchyma.


Assuntos
Encéfalo/fisiologia , Circulação Cerebrovascular , Óxido Nítrico/metabolismo , Anemia Falciforme/fisiopatologia , Arteríolas , Transfusão de Sangue , Sistema Livre de Células , Simulação por Computador , Difusão , Células Endoteliais/metabolismo , Eritrócitos/metabolismo , Hemodinâmica , Humanos , Processamento de Imagem Assistida por Computador , Imageamento Tridimensional , Malária/fisiopatologia , Mitocôndrias/metabolismo , Músculo Liso/metabolismo , Oscilometria , Distribuição de Poisson , Transdução de Sinais , Vasodilatação
12.
Nat Commun ; 11(1): 3394, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32636383

RESUMO

The hypothalamic suprachiasmatic nuclei (SCN) are the principal mammalian circadian timekeeper, co-ordinating organism-wide daily and seasonal rhythms. To achieve this, cell-autonomous circadian timing by the ~20,000 SCN cells is welded into a tight circuit-wide ensemble oscillation. This creates essential, network-level emergent properties of precise, high-amplitude oscillation with tightly defined ensemble period and phase. Although synchronised, regional cell groups exhibit differentially phased activity, creating stereotypical spatiotemporal circadian waves of cellular activation across the circuit. The cellular circuit pacemaking components that generate these critical emergent properties are unknown. Using intersectional genetics and real-time imaging, we show that SCN cells expressing vasoactive intestinal polypeptide (VIP) or its cognate receptor, VPAC2, are neurochemically and electrophysiologically distinct, but together they control de novo rhythmicity, setting ensemble period and phase with circuit-level spatiotemporal complexity. The VIP/VPAC2 cellular axis is therefore a neurochemically and topologically specific pacemaker hub that determines the emergent properties of the SCN timekeeper.


Assuntos
Ritmo Circadiano , Receptores Tipo II de Peptídeo Intestinal Vasoativo/metabolismo , Núcleo Supraquiasmático/fisiologia , Peptídeo Intestinal Vasoativo/metabolismo , Animais , Relógios Circadianos , Criptocromos/genética , Feminino , Genes Reporter , Teste de Complementação Genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/fisiologia , Optogenética , Oscilometria , Transdução de Sinais , Núcleo Supraquiasmático/citologia
13.
Stud Health Technol Inform ; 272: 171-174, 2020 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-32604628

RESUMO

Invasive blood pressure (IBP) is the gold standard method for BP monitoring in critically ill patients. However, due to practical difficulties and complications, noninvasive methods may offer an alternative. We aim to evaluate an automatic oscillometry-based wrist BP monitor in critically ill patients compared to IBP. Forty five adult patients were included, and systolic, diastolic and mean BP (SBP, DBP, MBP) were simultaneously measured by IBP in the radial artery and by non-invasive blood pressure (NIBP) monitoring using the OMRON RS7 automatic wrist monitor. NIBP and IBP (mean ± SD) were: SBP 114 ± 18 vs 130 ± 18; DBP 63 ± 13 vs 63 ± 13; MBP 80 ± 13 vs 86 ± 15 mmHg. Bland-Altman analysis of the differences (NIBP-IBP) mean bias was: SBP -16; DPB 0.5 and MBP -6. The OMRON wrist monitor may not be sufficiently accurate compared to IBP in critically ill patients.


Assuntos
Monitores de Pressão Arterial , Punho , Pressão Sanguínea , Determinação da Pressão Arterial , Cuidados Críticos , Humanos , Oscilometria
14.
PLoS Comput Biol ; 16(7): e1007996, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32667909

RESUMO

Cortical spreading depression (CSD) is the propagation of a relatively slow wave in cortical brain tissue that is linked to a number of pathological conditions such as stroke and migraine. Most of the existing literature investigates the dynamics of short term phenomena such as the depolarization and repolarization of membrane potentials or large ion shifts. Here, we focus on the clinically-relevant hour-long state of neurovascular malfunction in the wake of CSDs. This dysfunctional state involves widespread vasoconstriction and a general disruption of neurovascular coupling. We demonstrate, using a mathematical model, that dissolution of calcium that has aggregated within the mitochondria of vascular smooth muscle cells can drive an hour-long disruption. We model the rate of calcium clearance as well as the dynamical implications on overall blood flow. Based on reaction stoichiometry, we quantify a possible impact of calcium phosphate dissolution on the maintenance of F0F1-ATP synthase activity.


Assuntos
Depressão Alastrante da Atividade Elétrica Cortical , Potenciais da Membrana , Mitocôndrias/metabolismo , Vasoconstrição , Trifosfato de Adenosina/química , Cálcio/química , Fosfatos de Cálcio/química , Córtex Cerebral/fisiopatologia , Circulação Cerebrovascular , Citosol/química , Retículo Endoplasmático/química , Substância Cinzenta/fisiopatologia , Humanos , Modelos Teóricos , Acoplamento Neurovascular , Oscilometria , Oxigênio/química , Fosforilação , ATPases Translocadoras de Prótons/química , Acidente Vascular Cerebral/fisiopatologia
15.
Artigo em Espanhol | PAHO-IRIS | ID: phr-52467

RESUMO

[RESUMEN]. La hipertensión arterial es una causa modificable muy prevalente de enfermedades cardiovasculares, accidentes cerebrovasculares y muerte. Medir con exactitud la presión arterial es fundamental, dado que un error de medición de 5 mmHg puede ser motivo para clasificar incorrectamente como hipertensas a 84 millones de personas en todo el mundo. En la presente declaración de posición se resumen los procedimientos para optimizar el desempeño del observador al medir la presión arterial en el consultorio, con atención especial a los entornos de ingresos bajos o medianos, donde esta medición se ve complicada por limitaciones de recursos y tiempo, sobrecarga de trabajo y falta de suministro eléctrico. Es posible reducir al mínimo muchos errores de medición con una preparación adecuada de los pacientes y el uso de técnicas estandarizadas. Para simplificar la medición y prevenir errores del observador, deben usarse tensiómetros semiautomáticos o automáticos de manguito validados, en lugar del método por auscultación. Pueden ayudar también la distribución de tareas, la creación de un área específica de medición y el uso de aparatos semiautomáticos o de carga solar. Es fundamental garantizar la capacitación inicial y periódica de los integrantes del equipo de salud. Debe considerarse la implementación de programas de certificación de bajo costo y fácilmente accesibles con el objetivo de mejorar la medición de la presión arterial.


[ABSTRACT]. High blood pressure (BP) is a highly prevalent modifiable cause of cardiovascular disease, stroke, and death. Accurate BP measurement is critical, given that a 5-mmHg measurement error may lead to incorrect hypertension status classification in 84 million individuals worldwide. This position statement summarizes procedures for optimizing observer performance in clinic BP measurement, with special attention given to low-to-middle-income settings, where resource limitations, heavy workloads, time constraints, and lack of electrical power make measurement more challenging. Many measurement errors can be minimized by appropriate patient preparation and standardized techniques. Validated semi-automated/automated upper arm cuff devices should be used instead of auscultation to simplify measurement and prevent observer error. Task sharing, creating a dedicated measurement workstation, and using semi-automated or solar-charged devices may help. Ensuring observer training, and periodic re-training, is critical. Low-cost, easily accessible certification programs should be considered to facilitate best BP measurement practice.


[RESUMO]. A hipertensão é uma causa altamente prevalente de doença cardiovascular, acidente vascular cerebral e morte. A medição precisa da pressão arterial (PA) é um aspecto crítico, uma vez que erros de mensuração da ordem de 5 mmHg podem levar a uma classificação incorreta do status de hipertensão em 84 milhões de pessoas em todo o mundo. O presente posicionamento resume os procedimentos para otimizar o desempenho do observador (o indivíduo responsável pela mensuração da PA) na mensuração clínica da PA, com atenção especial para contextos de baixa a média renda, onde recursos limitados, cargas de trabalho pesadas, restrições de tempo e falta de energia elétrica tornam mais desafiadora a tarefa de medir a PA. Muitos erros de mensuração podem ser minimizados pela preparação adequada do paciente e pelo uso de técnicas padronizadas. Para simplificar a mensuração e evitar erros do observador, devem-se utilizar dispositivos semiautomatizados ou automatizados validados, com manguito para braço, ao invés de auscultação. O compartilhamento de tarefas, a criação de uma estação de trabalho dedicada à mensuração e o uso de dispositivos semiautomatizados ou com carga solar podem ajudar. É essencial que seja assegurado o treinamento e retreinamento periódico do observador. Programas de certificação de baixo custo e de fácil acesso devem ser considerados para facilitar a adoção das melhores práticas na mensuração da PA.


Assuntos
Pressão Arterial , Equipamentos de Medição , Consenso , Saúde Global , Hipertensão , Oscilometria , Pressão Arterial , Equipamentos de Medição , Consenso , Saúde Global , Hipertensão , Oscilometria , Pressão Arterial , Equipamentos de Medição , Saúde Global , Hipertensão , Oscilometria
16.
PLoS Comput Biol ; 16(6): e1007265, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32516336

RESUMO

Modern electrophysiological recordings and optical imaging techniques have revealed a diverse spectrum of spatiotemporal neural activities underlying fundamental cognitive processing. Oscillations, traveling waves and other complex population dynamical patterns are often concomitant with sensory processing, information transfer, decision making and memory consolidation. While neural population models such as neural mass, population density and kinetic theoretical models have been used to capture a wide range of the experimentally observed dynamics, a full account of how the multi-scale dynamics emerges from the detailed biophysical properties of individual neurons and the network architecture remains elusive. Here we apply a recently developed coarse-graining framework for reduced-dimensional descriptions of neuronal networks to model visual cortical dynamics. We show that, without introducing any new parameters, how a sequence of models culminating in an augmented system of spatially-coupled ODEs can effectively model a wide range of the observed cortical dynamics, ranging from visual stimulus orientation dynamics to traveling waves induced by visual illusory stimuli. In addition to an efficient simulation method, this framework also offers an analytic approach to studying large-scale network dynamics. As such, the dimensional reduction naturally leads to mesoscopic variables that capture the interplay between neuronal population stochasticity and network architecture that we believe to underlie many emergent cortical phenomena.


Assuntos
Córtex Cerebral/fisiologia , Modelos Neurológicos , Neurônios/fisiologia , Oscilometria , Algoritmos , Tomada de Decisões , Fenômenos Eletrofisiológicos , Entropia , Humanos , Modelos Estatísticos , Imagem Óptica , Dinâmica Populacional , Processos Estocásticos , Sinapses/fisiologia
17.
Nat Commun ; 11(1): 3071, 2020 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-32555162

RESUMO

Unlimited access to calorie-dense, palatable food is a hallmark of Western societies and substantially contributes to the worldwide rise of metabolic disorders. In addition to promoting overconsumption, palatable diets dampen daily intake patterns, further augmenting metabolic disruption. We developed a paradigm to reveal differential timing in the regulation of food intake behavior in mice. While homeostatic intake peaks in the active phase, conditioned place preference and choice experiments show an increased sensitivity to overeating on palatable food during the rest phase. This hedonic appetite rhythm is driven by endogenous circadian clocks in dopaminergic neurons of the ventral tegmental area (VTA). Mice with disrupted clock function in the VTA lose their hedonic overconsumption rhythms without affecting homeostatic intake. These findings assign a functional role of VTA clocks in modulating palatable feeding behaviors and identify a potential therapeutic route to counteract hyperphagy in an obesogenic environment.


Assuntos
Ritmo Circadiano , Neurônios Dopaminérgicos/fisiologia , Comportamento Alimentar , Área Tegmentar Ventral/fisiologia , Animais , Apetite , Comportamento Animal , Comportamento de Escolha , Homeostase , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/metabolismo , Oscilometria
18.
PLoS Comput Biol ; 16(6): e1007776, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32555578

RESUMO

We show that logic computational circuits in gene regulatory networks arise from a fibration symmetry breaking in the network structure. From this idea we implement a constructive procedure that reveals a hierarchy of genetic circuits, ubiquitous across species, that are surprising analogues to the emblematic circuits of solid-state electronics: starting from the transistor and progressing to ring oscillators, current-mirror circuits to toggle switches and flip-flops. These canonical variants serve fundamental operations of synchronization and clocks (in their symmetric states) and memory storage (in their broken symmetry states). These conclusions introduce a theoretically principled strategy to search for computational building blocks in biological networks, and present a systematic route to design synthetic biological circuits.


Assuntos
Biologia Computacional/métodos , Redes Reguladoras de Genes , Biologia Sintética/métodos , Algoritmos , Animais , Arabidopsis , Bacillus subtilis , Simulação por Computador , Eletrônica , Escherichia coli , Humanos , Modelos Teóricos , Mycobacterium tuberculosis , Oscilometria , Salmonella
19.
Doc Ophthalmol ; 141(3): 293-305, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32542469

RESUMO

PURPOSE: The electroretinogram (ERG) has proven to be useful in the evaluation and monitoring of patients with posterior uveitis. ERG oscillatory potentials (OPs) are sometimes reduced in many uveitic eyes with otherwise grossly normal ERG responses. This study compares ERG parameters, including OPs, between patients with birdshot chorioretinopathy, other posterior uveitis, and controls. METHODS: This was a retrospective case-control study. Sixty-four patients seen at a clinical practice had a total of 93 visits during which ERG was performed on both eyes. ERG data from 93 age-matched controls were also collected. Root-mean-squared (RMS) energy of the OPs was calculated using Fourier analysis for 88 patients and 88 age-matched controls for whom complete data were available. Photopic flicker amplitudes, photopic flicker latencies, scotopic b-wave amplitudes, and OP RMS values were compared between patients and controls. Diagnostic performance was assessed using receiver operating characteristic (ROC) curves. RESULTS: The mean ages of patients and controls were 55.9 ± 10.8 (SD) years and 55.1 ± 11.5, respectively. 83% of the patients had a diagnosis of BCR. The mean OP RMS value was significantly different in patients (15.6 µV ± 9.7 µV) versus control eyes (33.0 µV ± 12.7 µV), p < 0.001. Area under the ROC curves (AUROC) was 0.75 for photopic flicker amplitudes, 0.77 for photopic flicker latencies, 0.72 for scotopic b-wave amplitudes, and 0.88 for OP RMS. AUROC was significantly different between OP RMS and photopic flicker amplitudes (p < 0.001), between OP RMS and flicker latencies (p = 0.0032), and between OP RMS and scotopic b-wave amplitudes (p < 0.0001). CONCLUSION: Analysis of OPs shows greater sensitivity and specificity in the diagnosis and evaluation of patients with birdshot chorioretinopathy than photopic and scotopic ERG amplitudes and photopic flicker latencies.


Assuntos
Coriorretinopatia de Birdshot/fisiopatologia , Eletrorretinografia , Retina/fisiopatologia , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Oscilometria , Estimulação Luminosa , Curva ROC , Estudos Retrospectivos , Uveíte Posterior/fisiopatologia , Acuidade Visual/fisiologia
20.
Can Vet J ; 61(5): 481-498, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32355347

RESUMO

Arterial blood pressure is a common parameter evaluated in conscious and anesthetized veterinary patients for a variety of reasons. Non-invasive blood pressure measurement techniques, such as Doppler ultrasound and oscillometry, are attractive in certain veterinary patients due to their availability and ease of use. The greatest limitation to non-invasive blood pressure monitoring can be its inaccuracy, particularly in hypotensive or hypertensive patients and in certain species. Part 1 of this 2-part review summarized the current techniques available to non-invasively measure arterial blood pressure in veterinary species and discussed validation of non-invasive devices. Part 2 summarizes the veterinary literature that evaluates the use of non-invasive blood pressure measurement techniques in conscious and anesthetized species and develops general conclusions for proper use and interpretation of non-invasive blood pressure devices.


Assuntos
Determinação da Pressão Arterial/veterinária , Hipotensão/veterinária , Animais , Pressão Arterial , Pressão Sanguínea , Oscilometria/veterinária
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