A method for photoplethysmography signal quality assessment fusing multi-class features with multi-scale series information / 生物医学工程学杂志

Photoplethysmography (PPG) is often affected by interference, which could lead to incorrect judgment of physiological information. Therefore, performing a quality assessment before extracting physiological information is crucial. This paper proposed a new PPG signal quality assessment by fusing multi-class features with multi-scale series information to address the problems of traditional machine learning methods with low accuracy and deep learning methods requiring a large number of samples for training. The multi-class features were extracted to reduce the dependence on the number of samples, and the multi-scale series information was extracted by a multi-scale convolutional neural network and bidirectional long short-term memory to improve the accuracy. The proposed method obtained the highest accuracy of 94.21%. It showed the best performance in all sensitivity, specificity, precision, and F1-score metrics, compared with 6 quality assessment methods on 14 700 samples from 7 experiments. This paper provides a new method for quality assessment in small samples of PPG signals and quality information mining, which is expected to be used for accurate extraction and monitoring of clinical and daily PPG physiological information.

Effect of dental tissue thickness on the measurement of oxygen saturation by two different pulse oximeters

Abstract This study aimed to evaluate the influence of different dental tissue thickness on the measurement of oxygen saturation (SpO2) levels in high (HP) and low (LP) blood perfusion by comparing the values obtained from two different pulse oximeters (POs) - BCI and Sense 10. Thirty freshly extracted human teeth had their crowns interposed between the POs and an optical simulator, which emulated the SpO2 and heart beats per minute (bpm) at HP (100% SpO2/75 bpm) and LP (86% SpO2/75 bpm) modes. Afterwards, the palatine/lingual surfaces of the dental crowns were worn with diamond drills. The reading of SpO2 was performed again using the POs alternately through the buccal surface of each dental crown. Data were analyzed by the Wilcoxon, Mann-Whitney and Kendall Tau-b tests (α=5%). The results showed significant difference at the HP and LP modes in the SpO2 readouts through the different dental thicknesses with the use of BCI, and at the LP mode with the use of Sense 10, which had a significant linear correlation (p<0.0001) and lower SpO2 readout values in relation to the increase of the dental thickness. Irrespective of tooth thickness, Sense 10 had significantly higher readout values (p<0.0001) than BCI at both perfusion modes. The interposition of different thicknesses of enamel and dentin influenced the POs measurement of SpO2, specially at the low perfusion mode. The POs were more accurate in SpO2 measurement when simulated perfusion levels were higher.

Resumo Este estudo avaliou a influência de diferentes espessuras de esmalte e dentina na medição dos níveis de saturação de oxigênio (SpO2) em alta (HP) e baixa (LP) perfusão sanguínea, comparando os valores obtidos em dois oxímetros de pulso (OPs) diferentes, BCI e Sense 10. Trinta dentes recém-extraídos de humanos tiveram suas coroas interpostas entre os OPs e um simulador óptico, que simulava a SpO2 e os batimentos cardíacos por minuto (bpm) nos modos de HP (100% SpO2 / 75 bpm) e LP (86% SpO2 / 75 bpm). Após, as superfícies palatinas / linguais dos dentes foram desgastadas com brocas de diamantadas. A leitura da SpO2 foi realizada novamente usando os dois OPs alternadamente através da face vestibular de cada coroa dental. Os dados foram analisados ​​pelos testes Wilcoxon, Mann-Whitney e Kendall Tau-b (α = 5%). Os resultados mostraram diferença significativa nos modos HP e LP nas leituras de SpO2 através das diferentes espessuras dentárias com o uso do BCI, e no modo LP com o uso do Sense 10, que teve correlação linear significativa (p <0,0001) e menores valores de leitura de SpO2 em relação ao aumento da espessura dentária. Independentemente da espessura do dente, o Sense 10 apresentou valores de leitura significativamente maiores (p <0,0001) do que o BCI em ambos os modos de perfusão. A interposição de diferentes espessuras de esmalte e dentina influenciaram a mensuração da SpO2 pelos OPs, especialmente no modo de baixa perfusão. Os POs foram mais precisos na mensuração da SpO2 quando os níveis simulados de perfusão foram maiores.

Development of Respiratory Signal Monitoring System Based on Photoplethysmography / 中国医疗器械杂志

Breathing is of great significance in the monitoring of patients with obstructive sleep apnea hypopnea syndrome, perioperative monitoring and intensive care. In this study, a respiratory monitoring and verification system based on optical capacitance product pulse wave (PPG) is designed, which can synchronously collect human PPG signals. Through algorithm processing, the characteristic parameters of PPG signal are calculated, and the respiratory signal and respiratory frequency can be extracted in real time. In order to verify the accuracy of extracting respiratory signal and respiratory rate by the algorithm, the system adds the nasal airflow respiratory signal acquisition module to synchronously collect the nasal airflow respiratory signal as the standard signal for comparison and verification. Finally, the root mean square error between the respiratory rate extracted by the algorithm from the pulse wave and the standard respiratory rate is only 1.05 times/min.

Heart rate extraction algorithm based on adaptive heart rate search model / 生物医学工程学杂志

Photoplethysmography (PPG) is a non-invasive technique to measure heart rate at a lower cost, and it has been recently widely used in smart wearable devices. However, as PPG is easily affected by noises under high-intensity movement, the measured heart rate in sports has low precision. To tackle the problem, this paper proposed a heart rate extraction algorithm based on self-adaptive heart rate separation model. The algorithm firstly preprocessed acceleration and PPG signals, from which cadence and heart rate history were extracted respectively. A self-adaptive model was made based on the connection between the extracted information and current heart rate, and to output possible domain of the heart rate accordingly. The algorithm proposed in this article removed the interference from strong noises by narrowing the domain of real heart rate. From experimental results on the PPG dataset used in 2015 IEEE Signal Processing Cup, the average absolute error on 12 training sets was 1.12 beat per minute (bpm) (Pearson correlation coefficient: 0.996; consistency error: -0.184 bpm). The average absolute error on 10 testing sets was 3.19 bpm (Pearson correlation coefficient: 0.990; consistency error: 1.327 bpm). From experimental results, the algorithm proposed in this paper can effectively extract heart rate information under noises and has the potential to be put in usage in smart wearable devices.

Development of Respiratory Signal Extraction System Based on Photoplethysmography / 中国医疗器械杂志

Oxygen saturation and respiratory signals are important physiological signals of human body, respiratory monitoring plays an important role in clinical and daily life. A system was established to extract respiratory signals from photoplethysmography in this study. Including the collection of pulse wave signal, the extraction of respiratory signal, and the calculation of respiratory rate and pulse rate transmitted from the slave computer to the host computer in real time.

A Light Adaptive Heart Rate Detection Method Based on Webcam / 中国医疗器械杂志

In order to extract the pulse wave signal of blood volume effectively in the case of uneven light, a light-adaptive heart rate detection method based on webcam was proposed. In this method, adaptive gamma transform is applied to face image sequence to eliminate the influence of illumination. The pulse wave source signal was extracted from the forehead area and the blood volume pulse wave was obtained by wavelet filtering. The heart rate is estimated by Fourier transform analysis. The Bland-Altman analysis indicates that the method used in this paper is in good agreement with the measurement results of the electronic sphygmomanometer, and the adaptive gamma transformation used in this paper eliminates the influence of light interference, and the measurement error of heart rate is significantly reduced, which is completely able to meet the requirements of daily heart rate monitoring.

Assessing Accuracy of Wrist-Worn Wearable Devices in Measurement of Paroxysmal Supraventricular Tachycardia Heart Rate

BACKGROUND AND OBJECTIVES: Wrist-worn wearable devices provide heart rate (HR) monitoring function via photoplethysmography technology. Recently, these devices have been used by patients to measure the HR when palpitation occurs, but few validation studies of these instruments have been conducted. We assessed the accuracy of these devices for measuring a HR. METHODS: This study enrolled 51 consecutive patients with a history of paroxysmal supraventricular tachyarrhythmia (SVT) or paroxysmal palpitations who were scheduled to undergo an electrophysiological study (EPS). Three devices were assessed: Apple Watch Series 2 (Apple), Samsung Galaxy Gear S3 (Galaxy), and Fitbit Charge 2 (Fitbit). Patients were randomly assigned to wear 2 different devices. The HR at baseline and induced SVT were measured during the EPS. After successful ablation of SVT, HR measurements was also done during atrial and ventricular pacing study. RESULTS: The mean patient age was 44.4±16.6 years and 27 patients were male (53%). The accuracy (within ±5 beats per minute [bpm] of an electrocardiogram [ECG] measurement) of the baseline HR measurements was 100%, 100%, and 94%, for Apple, Galaxy, and Fitbit, respectively. The HR during induced SVT ranged from 108 bpm to 228 bpm and the accuracy (within ±10 bpm of an ECG) was 100%, 90%, and 87% for the Apple, Galaxy, and Fitbit, respectively. During pacing study, accuracy of these devices was also acceptable but tended to decrease as the HR increased, and showed differences between the devices. CONCLUSIONS: Wrist-worn wearable devices accurately measure baseline and induced SVT HR. TRIAL REGISTRATION: Clinical Research Information Service Identifier: KCT0002282

Correlation between characteristic parameters of photoplethysmography and severity of coronary artery lesions / 中华老年心脑血管病杂志

Objective To study the correlation between characteristic parameters of photoplethysmography( PPG)and severity of coronary artery lesions.Methods Two hundred and twenty-six CHD patients who underwent CAG in our hospital from August 2018to November 2018were divided into single-vessel lesion group(n=55),double-vessel lesion group(n=74)and multi-vessel lesion group(n=97)according to their CAG.Their stiffness index(SI),crest time(CT),normalized crest time(NCT)and crest time ratio(CTR)were recorded by PPG and analyzed by correlation analysis.Results The SI was significantly different in single-vessel lesion group,double-vessel lesion group and multi-vessel lesion group(6.479±0.819m/s,6.692±1.051m/s and 6.943±1.096m/s,P=0.024).No significant difference was detected in CT,NCT and CTR among single-vessel lesion group,double-vessel lesion group and multi-vessel lesion group(P＞0.05).The SI was positively correlated with the severity of coronary artery lesions(r=0.162,P=0.015).Conclusion The SI is correlated with the severity of coronary artery lesions,which is of a certain value in predicting the severity of coronary artery lesions.

An Automatic Recognition Algorithm for Feature Points of Photoplethysmography / 医用生物力学

Objective In order to make up for the deficiency in the existing photoplethysmography feature point recognition algorithms which need manually setting the selecting threshold and have poor adaptability to complex waveforms, an automatic reognition algorithm for feature points based on monotonic increase in geometrical characteristics of pulse wave ascending branch was proposed. Methods A ‘reference point’ was determined in each pulse period by zero crossing detection after two Hilbert transformation. The nearest concave and convex inflection points that searched around the ‘reference points’ were the notchs and systolic peaks. Results By using the 18 sets of data in the MIT-BIH standard database for verification, the average sensitivity, precision and detection accuracy reached 99.94%, 99.72% and 99.68%, respectively. Compared with the existing four algorithms, there was a significant improvement in the precision. Feature points could still be accurately identified for complex waveforms. Conclusions The proposed algorithm achieved a higher detection accuracy in the process of searching and determining the position of the pulse wave notchs and systolic peaks, and exhibited a stronger adaptability to the waveform change. The research results provide a good foundation for physiological and pathological analysis through pulse wave features extraction in clinic.

An Automatic Recognition Algorithm for Feature Points of Photoplethysmography / 医用生物力学

Objective In order to make up for the deficiency in the existing photoplethysmography feature point recognition algorithms which need manually setting the selecting threshold and have poor adaptability to complex waveforms, an automatic reognition algorithm for feature points based on monotonic increase in geometrical characteristics of pulse wave ascending branch was proposed. Methods A ‘reference point’ was determined in each pulse period by zero crossing detection after two Hilbert transformation. The nearest concave and convex inflection points that searched around the ‘reference points’ were the notchs and systolic peaks. Results By using the 18 sets of data in the MIT-BIH standard database for verification, the average sensitivity, precision and detection accuracy reached 99.94%, 99.72% and 99.68%, respectively. Compared with the existing four algorithms, there was a significant improvement in the precision. Feature points could still be accurately identified for complex waveforms. Conclusions The proposed algorithm achieved a higher detection accuracy in the process of searching and determining the position of the pulse wave notchs and systolic peaks, and exhibited a stronger adaptability to the waveform change. The research results provide a good foundation for physiological and pathological analysis through pulse wave features extraction in clinic.

Comparação do índice tornozelo-braquial com parâmetros de rigidez e resistência arterial periférica avaliados por fotopletismografia em idosos / Comparison of the ankle-brachial index with parameters of stiffness and peripheral arterial resistance assessed by photoplethysmography in elderly patients

O índice tornozelo-braquial (ITB) utiliza a razão entre a pressão arterial sistólica do tornozelo e do braço para diagnosticar de forma não invasiva a doença arterial periférica (DAP). A fotopletismografia (photoplethysmography, PPG) faz a medição e o registro das modificações de volume sanguíneo do corpo humano por meio de técnicas ópticas. Objetivos O objetivo deste estudo foi comparar o ITB com parâmetros de rigidez arterial e resistência periférica avaliados pela PPG em idosos e propor um modelo de predição para o ITB. Métodos Foi realizado um estudo transversal quantitativo. A amostra foi composta por idosos atendidos no ambulatório médico de especialidades da Universidade do Sul de Santa Catarina (UNISUL). Foram verificados: idade, sexo, índice de massa corporal (IMC), presença de comorbidades, tabagismo e atividade física. Para comparação das variáveis obtidas com a PPG com o ITB, foi realizada regressão linear bivariada e multivariada, considerando erro α = 0,05. Resultados Foram avaliados 93 idosos, sendo 63,4% mulheres. Em 98,9% dos casos, o ITB apresentou-se dentro da normalidade. Na comparação do ITB e variáveis derivadas da PPG em relação à idade, foram demonstradas associações significativas. Contudo, não foram observadas associações significativas entre ITB e PPG. O modelo multivariado indicou que apenas idade, sexo e tabagismo foram associados ao ITB. Conclusões Como conclusão, o ITB e a PPG demonstraram associação com o envelhecimento arterial, tendo em vista sua correlação com a idade; contudo, o ITB foi relacionado apenas com idade, sexo e tabagismo. Mais estudos são necessários para avaliar o potencial uso da PPG como rastreio de doenças vasculares em rotinas ambulatórias

The ankle-brachial index (ABI) uses the ratio between systolic blood pressures at the ankle and the arm to diagnose peripheral arterial disease (PAD) noninvasively. Photoplethysmography (PPG) measures and records changes to the blood volume in the human body using optical techniques. Objectives The objective of this study was to compare ABI with arterial stiffness and peripheral resistance parameters assessed using PPG in elderly patients and to propose a model for prediction of ABI. Methods A cross-sectional, quantitative study was conducted. The sample comprised elderly patients seen at a medical specialties clinic at the Universidade do Sul de Santa Catarina (UNISUL), Brazil. Age, sex, body mass index (BMI), comorbidities, smoking, and physical activity were recorded. The variables obtained using PPG and ABI were compared using bivariate and multivariate linear regression, with an α error of 0.05. Results A total of 93 elderly patients were assessed, 63.4% of whom were women. In 98.9% of cases, ABI was within normal limits. Comparison of ABI with variables acquired by PPG revealed significant associations with age. However, no significant associations were observed between ABI and PPG. The multivariate model indicated that only age, sex, and smoking were associated with ABI. Conclusions In conclusion, ABI and PPG exhibited associations with arterial aging, considering its correlation with age. However, ABI was only related to age, sex, and smoking. More studies are needed to evaluate the potential uses of PPG for screening for vascular diseases in ambulatory settings

Application of photoplethysmography in monitoring changes of noxious stimulation intensity during pediatric laparoscopic hernia repair / 第二军医大学学报

To explore the feasibility of photoplethysmography in monitoring the changes of noxious stimulation intensity caused by veress needle insertion during pediatric laparoscopic hernia repair. Methods Ninety pediatric patients (2-4 years old) with the American Society of Anesthesiologists (ASA) grade of I-II scheduled for laparoscopic hernia repair surgery were randomized into three groups (n=30): group A, B, and C. After tracheal intubation of general anesthesia induction, the pediatric patients in group A received intravenous 0.1 μg/kg sufentanil 5 min before veress needle insertion, group B received 0.1 μg/kg sufentanil immediately after placing the veress needle, while group C received veress needle insertion without sufentanil. The photoplethysmographic amptitude (PPGA) from right forefinger, and surface electromyography (sEMG) of abdominal muscles of pediatric patients were recorded at 6 min prior to veress needle insertion (that is 1 min before receiving sufentanil in the group A, and the injection time was not included, T1), immediately after veress needle insertion (T2), and at 5 min after veress needle insertion (that is 5 min after administration of sufentanil in the group B, T3). Results The values of PPGA had no significant difference between T1, T2 and T3 in group A (P>0.05). Compared with T1 and T3, the value of PPGA at T2 was significantly decreased in group B (P<0.05). The values of PPGA at T2 and T3 were significantly decreased compared with T1 in group C (P<0.05). PPGA was negatively correlated with sEMG in three groups (r=-0.601, -0.512, -0.613; P<0.05). Conclusion Photoplethysmography can quantify the changes of noxious stimulation intensity in pediatric laparoscopic hernia repair and has good application values.

Research on Automatic Identification System of Traditional Chinese Medicine Constitution Based on Pulse Wave / 世界科学技术-中医药现代化

This study was aimed to explore the feasibility of identification of traditional Chinese medicine (TCM) constitution based on photoplethysmography (PPG) frequency domain analysis,and to establish an automatic identification system (AIS) of TCM constitution with simple operation and good generalization.The Classification and Determination of Constitution in TCM was used to evaluate the subjects' constitutional state.Pulse wave sensor was used to collect the pulse wave signal.Spectral characteristics were analyzed by power spectrum analysis.Eight classification algorithms of data mining were used to establish the model of qi-insufficiency constitution.The results showed that the pulse wave harmonic peak was that qi-insufficiency constitution was higher than health group;the model was optimal when random forest algorithm was used;and the accuracy of 10-CV test was 80.4％.Sensitivity reached 73.2％.Specificity and receiver operator characteristic were all above 0.8.The model has certain reliability.It was concluded that it was feasible to identify qiinsufficiency constitution by means of frequency domain analysis of PPG.It provides preliminary work for the construction of AIS of TCM constitution as well as a simple and quick assistant tool for the constitution identification of subhealth group in family health care.

System for Collecting Biosignal Data from Multiple Patient Monitoring Systems / 대한의료정보학회지

OBJECTIVES: Biosignal data include important physiological information. For that reason, many devices and systems have been developed, but there has not been enough consideration of how to collect and integrate raw data from multiple systems. To overcome this limitation, we have developed a system for collecting and integrating biosignal data from two patient monitoring systems. METHODS: We developed an interface to extract biosignal data from Nihon Kohden and Philips monitoring systems. The Nihon Kohden system has a central server for the temporary storage of raw waveform data, which can be requested using the HL7 protocol. However, the Philips system used in our hospital cannot save raw waveform data. Therefore, our system was connected to monitoring devices using the RS232 protocol. After collection, the data were transformed and stored in a unified format. RESULTS: From September 2016 to August 2017, we collected approximately 117 patient-years of waveform data from 1,268 patients in 79 beds of five intensive care units. Because the two systems use the same data storage format, the application software could be run without compatibility issues. CONCLUSIONS: Our system collects biosignal data from different systems in a unified format. The data collected by the system can be used to develop algorithms or applications without the need to consider the source of the data.

New Aging Index Using Signal Features of Both Photoplethysmograms and Acceleration Plethysmograms / 대한의료정보학회지

OBJECTIVES: Acceleration plethysmograms (APGs) are obtained by taking the second derivative of photoplethysmograms (PPGs) and are noninvasive circulatory signals related to risk factors for atherosclerosis with age. There has been growing interest in the development of mobile devices to collect and analyze PPG single features for ambulatory health monitoring. The present study aimed to extract a new feature from the morphologies of APG and PPG signals to classify the dominant indices related to the pulsatile volume of blood in tissue according to age. METHODS: Ten APG and 14 PPG indices were simultaneously extracted. All indices were compared via Pearson correlation coefficients (r) and a regression analysis. We introduced a combined index extracted from both the PPG and APG indices defined as the inflection point area plus the d_peak (IPAD). The participants included 93 healthy adults aged 36–86 years with a mean ± standard deviation age of 57.43 ± 11.99 years. RESULTS: The d_peak and age index for the APG indices were significantly correlated with age (r = −0.408, p < 0.0001 and r = 0.296, p = 0.0039, respectively). Only the A1 time for PPG indices was moderately correlated with age (r = −0.247, p = 0.017). The stiffness index, including individual height information, was not related to age (r = −0.031, p = 0.7713). However, the combined IPAD index was significantly more correlated with age (r = 0.56, p < 0.001) than the other indices. CONCLUSIONS: The proposed index outperformed the other 24 indices for evaluating vascular aging. We suggest that the IPAD is a significant factor related to the clinical information embedded in the PPG waveform.

Validity and reliability of a set of sexual stimuli in a sample of Colombian heterosexual young women / Validez y fiabilidad de un set de estímulos sexuales en una muestra de jóvenes mujeres heterosexuales colombianas

Vaginal photoplethysmography is a method for physiological evaluation of sexual arousal in women. This paper undertook to obtain the validity and reliability of a set of sexual stimuli in young heterosexual women. Six six-minute video clips were selected. A total of 34 women aged 18-30 years(M = 22.38, SD = 2.52) participated in this study. Objective Sexual Arousal, Subjective Sexual Arousal, emotional activation, emotional valence and socio-psycho-sexual information were evaluated. Three of the six sexual stimuli were selected from the scores obtained after the experimental phase. It was observed that the aforementioned video clips produced the most arousal-activation-pleasure, with internally consistent measures. As expected, good indicators of external validity were observed, with statistically significant differences. According to the data obtained, the pooled use of the three stimuli increases the like lihoodof obtainingan objective arousal response in healthy young women, there by minimizing the possibilities of displeasure.

La fotopletismografía vaginal es un método para evaluar fisiológicamente la excitación sexual objetiva en mujeres. El objetivo del presente estudio es obtener la validez y fiabilidad de un set de estímulos sexuales en mujeres jóvenes heterosexuales. Se seleccionaron seis videos sexuales de 6 minutos de duración. Un total de 34 mujeres entre los 18 y 30 años (M = 22.38; SD = 2.52) participaron en este estudio. Se evaluó la Excitación Sexual Objetiva, Subjetiva, la activación y valencia emocional e información sociopsicosexual. Tres de los seis estímulos sexuales se seleccionaron a partir de las puntuaciones obtenidas luego de la fase experimental. Se observó que estos fueron los que mayor excitación-activación-agrado produjeron con medidas internamente consistentes. Se observaron buenos indicadores de validez externa con diferencias estadísticamente significativas, como era de esperarse. Según los datos obtenidos, el uso agrupado de los tres estímulos aumentan la probabilidad de obtener unarespuesta de excitación objetiva en mujeres jóvenes saludables y minimizan las posibilidades de desagrado.

Alteraciones de la microcirculación en pacientes con anemia drepanocítica según técnicas fotopletismográficas / Changes of microcirculation in patients with sickle-cell anemia according to photoplethysmographical techniques

Se realizó un estudio observacional, descriptivo y transversal, de serie de casos, de 74 individuos (24 con anemia drepanocítica y 50 aparentemente sanos portadores de hemoglobinopatía SS), quienes asistieron a la Consulta de Hematología Especial del Hospital General Docente "Dr. Juan Bruno Zayas Alfonso" de Santiago de Cuba, durante el periodo 2013-2014, con vistas a identificar las alteraciones de la microcirculación según variabilidad de los parámetros fotopletismográficos. Se realizaron estudios con el Angiodin PD 3000, a partir del registro basal de la onda de volumen de pulso y el test de hiperemia reactiva. La fotopletismografía en estado basal de miembros inferiores mostró que los pacientes con anemia drepanocítica presentaron alteraciones en el sistema circulatorio, en tanto, las macroangiopatías tuvieron mayor frecuencia en la hiperemia reactiva. Los resultados obtenidos revelaron la utilidad de estas pruebas en la detección de trastornos funcionales circulatorios.

An observational, descriptive and cross-sectional cases series study, of 74 individuals (24 with sickel-cell anemia and 50 apparently healthy with hemoglobinopathies SS) who attended the Special Hematology Department from "Dr. Juan Bruno Zayas Alfonso" Teaching General Hospital in Santiago de Cuba was carried out during the period 2013-2014, with the aim of identifying the changes of the microcirculation according to variability of the photopletismographical parameters. Studies with the Angiodin PD 3000 were carried out, from the basal register of the pulse volume wave and the reactive hyperemia test. The photoplethysmography in basal state of lower members showed that patients with sickle-cell anemia presented changes in the circulatory system, while, the macroangiopathies had higher frequency in the reactive hyperemia. The obtained results revealed the usefulness of these tests in the detection of circulatory functional disorders.

MÉTODO ALTERNATIVO DE CONTROL DE INTENSIDAD LUMÍNICA PARA PULSIOXIMETRÍA EN TIEMPO REAL / AN ALTERNATIVE METHOD FOR POWER CONTROL OF LUMINICINTENSITY IN PULSEOXIMETRY ON REAL TIME / MÉTODO ALTERNATIVO DE CONTROLE DE INTENSIDADE DALUZ PARÁGRAFO OXIMETRIATEMPO REAL

El pulsioxímetro es una herramienta no invasiva esencial para el monitoreo de la saturación arterial de oxígeno. Utiliza la espectrofotometría para detectar sobre la piel dos intensidades de luz (600 y 900 nm) que proporcionan información de la perfusión tisular y cantidad de oxígeno transportada. Depende de un circuito de manipulación de corriente, dos diferentes fuentes emisoras de luz, un foto-detector y una unidad de procesamiento que permiten ajustar las intensidades de luz ante tejidos de diferentes características. En el presente trabajo, se propone un método de modulación por ancho de pulso alternativo para el control de la intensidad lumínica media, cuyo principio es la conmutación on/off de la corriente aplicada a los LEDs en la etapa de emisión. Este sistema permite modificar tanto el nivel de CD como la amplitud de la señal de CA de la onda fotopletismográfica e implica la reducción del número de componentes analógicos y consumo de energía. La metodología presentada permite regular la resolución de la señal muestreada y ofrece disminuciones del 21 % y 40 % en potencia comparado con los esquemáticos propuestos por Freescale Semiconductor, Inc. y Texas Instruments Incorporated respectivamente. El uso de señales sincronizadas moduladas en ancho de pulso con frecuencias por encima de 333 kHz y pasos de 50 ns para emitir luz, permitió una reducción 41% de potencia, respecto al sistema con modulación analógica del módulo MDK pulse oximeter.

Pulse oximetry is an essential optical based non-invasive tool for monitoring blood oxygen saturation. It uses spectrophotometry to detect two light intensities (600 and 900 nm) through the skin; it provides information on tissue perfusion and quantity of transported oxygen. The process relies on a current control circuit, two light emitting sources, a photodetector, and a digital signal processor that adjusts the light intensities for different tissue characteristics. This paper proposes an alternative method of pulse width modulation for controlling the mean light intensity level, whose principle is a pulse width nodulation of the current applied to the LEDs in the emitting stage. This system allows modifying the DC level and the amplitude of the AC signal of the photopletismographic wave. The results is the reduction of the number of analog components and power consumption. The methodology presented, it allows adjusting the definition of the sample signal and offers power reductions of 21% and 40% compared to schematics given by Freescale Semiconductor, Inc. and Texas Instruments Incorporated, respectively. Thus, by using synchronized signal pulse width modulation to emit light, with frequencies above 333 kHz and steps of 50 ns, it will allow power reductions of 41%, compared to the conventional analog modulation module MDK pulse oximeter.

O oxímetro de pulso é uma ferramenta não invasiva essencial para o monitoramento da saturação de oxigênio no sangue. Usa espectrofotometria para detectar a pele duas intensidades de luz (600 nm e 900) para fornecer informações de perfusão tecidual ea quantidade de oxigênio transportado. Depende de manuseamento corrente do circuito, duas fontes diferentes emissores de luz, um fotodetector e uma unidade de processamento para ajustar a intensidade da luz nos tecidos com características diferentes. Neste trabalho, um método de modulação de largura de pulso alternativa para controlar a intensidade de luz média, o princípio é o de ligar/desligar da corrente aplicada aos LEDs no palco questão é proposto. Este sistema permite modificar tanto o nível DC e a amplitude do sinal AC da forma de onda fotoplestimográfico e envolve a redução do número de componentes analógicos e consumo de energia. A metodologia apresentada permite ajustar a resolução do sinal de amostragem e oferece reduções de 21% e 40% da potência em comparação com o esquema proposto pela Freescale Semicondutor, Inc. e Texas Instruments Incorporated, respectivamente. Sinais sincronizados usando freqüências moduladas por largura de pulso acima de 333 kHz e 50 ns passos para emitir luz, permitiu uma redução de 41% de energia em comparação com módulo de oxímetro de pulso MDK sistema de modulação analógica.

Evaluation of quality of life and photoplethysmography in patients with chronic venous insufficiency treated with foam sclerotherapy

BACKGROUND: Ultrasound-guided foam sclerotherapy plays a major role in treatment of chronic venous insufficiency, providing clinical and hemodynamic improvement to patients undergoing treatment.OBJECTIVES: To examine the relationships between venous refilling time and impact of venous disease on quality of life and between changes in venous refilling time and improvement of symptoms after ultrasound-guided foam sclerotherapy for chronic venous insufficiency. METHODS: Thirty-two patients classified as C4, C5 or C6 answered a questionnaire on quality of life and symptoms and their venous filling time was measured using photoplethysmography before and 45 days after treatment of chronic venous insufficiency with ultrasound-guided foam sclerotherapy.RESULTS: Statistically significant improvements were observed in quality of life scores and in venous filling time and in the following symptoms: aching, heavy legs, restless legs, swelling, burning sensations, and throbbing (p<0.0001). A similar improvement was also seen in the work and social domains of quality of life (p<0.0001).CONCLUSIONS: As confirmed by questionnaire scores and venous refilling times, ultrasound-guided foam sclerotherapy demonstrated efficacy and resulted in high satisfaction levels and low rates of major complications.

CONTEXTO: A escleroterapia com espuma guiada por ultrassom (EGUS) ocupa lugar de destaque no tratamento da insuficiência venosa crônica (IVC), proporcionando melhora clínica e hemodinâmica aos pacientes submetidos ao tratamento.OBJETIVOS: Verificar a correlação entre dados obtidos por questionário de qualidade de vida e de sintomas com dados obtidos por fotopletismografia (FPG), antes e depois do tratamento por escleroterapia com espuma guiada por ultrassom (EGUS) da insuficiência venosa crônica (IVC). MÉTODOS: Um grupo de 32 pacientes, classificados como C4, C5 e C6, foi submetido à aplicação de questionário de qualidade de vida e sintomas, sendo aferido o tempo de enchimento venoso (TEV) por FPG antes e 45 dias depois do tratamento da IVC através de EGUS. O teste do sinal foi utilizado para análise estatística da melhora dos escores dos questionários e do TEV. O teste de McNemar foi utilizado para avaliação da melhora nos sintomas e do impacto do tratamento nas atividades laborais e sociais dos pacientes.RESULTADOS: Houve melhora nos escores dos questionários de qualidade de vida e no TEV, com significância estatística (p<0,0001). Houve melhora estatisticamente significativa nos sintomas: dor, cansaço, edema, queimação, pernas inquietas e latejamento (p<0,0001). Incremento na qualidade laboral e social após o tratamento apresentou melhora estatisticamente significativa (p<0,0001). Não ocorreram complicações maiores ou efeitos adversos nesta série.CONCLUSÕES: A EGUS mostrou-se eficaz, com alto índice de satisfação e baixas taxas de complicacões maiores, ratificada pelos escores dos questionários e pelos TEVs aferidos pela FPG.

Accuracy of photoplethysmograph pulse wave in monitoring stress response from harmfulness during anesthetic induction / 天津医药

Objective To envaluate the accuracy of Photoplethysmograph pulse wave in monitoring stress reaction to harmful stimulation. Methods Patients (n=75) were randomly assigned to three groups according to the dosages of fentanyl that were administrated ( 4, 5 and 6 g/kg were given to F4, F5, F6 group respectively (n=25) in each group. Heart rate (HR), Systemic blood pressure (SBP), Diastolic blood pressure (DBP), SpO2, the skin temperature of finger, perfusion index (PI), epi?nephrine(E) and Norepinephrine (NE) were recorded at following time points:just in operation room (T1), 2 min after induc?tion (T2), at intubation (T3),1 min (T4) and 5 min (T5) after intubation. And the PPGPW was printed and measured at the same time points. Results PPGA and PI were significantly increased while E and NE were significantly decreased in T2 and T5, compared with those baseline at T1 (P < 0.05). At T3, PPGA and PI were significantly decreased while NE markedly in?creased in group F4 and F5 compared to T1. At T3, E in group F4 were remarkably increased h while E in group F5 were of no obvious changed, compared with those at T1(P<0.05). PPGA and PI increased while E and NE decreased in group F6 at T2, T3 ,T4 and T5 compared with those at T1 (P<0.05). In summary, PI was negatively correlated with plasma E and NE while PP?GA was negatively correlated with plasma E and NE .Conclusion PPGA and PI are negatively associated with intensity of stress response. And they can reflect the stress reaction during the induction period of intravenous anesthesia accurately.