Resource Use and Clinical Outcomes in Infants with Supraventricular Tachycardia Monitored with the Owlet Smart Sock.

OBJECTIVES: To describe the prevalence of Owlet Smart Sock (OSS) use in infants with supraventricular tachycardia (SVT) and associated demographic and clinical characteristics of users and to analyze the association of OSS use on medical resource use and clinical outcomes from emergency department (ED) encounters for SVT. STUDY DESIGN: This was a single-center, retrospective cohort study of infants with confirmed SVT from 2015 to 2022. OSS users and nonusers were compared across clinical and demographic parameters. Medical resource use (phone calls, office visits, ED visits) and outcomes (need for intensive care, length of stay, echocardiographic function, clinical appearance) were compared between OSS users and nonusers. RESULTS: Of 133 infants with SVT, OSS was used by 31 of 133 (23%), purchased before SVT diagnosis in 5 in 31 (16%) of users. No demographic difference was found between OSS users and nonusers. OSS users had more phone notes than nonusers, (P = .002) and more ED visits (P = .03), but the number of office visits and medication adjustments did not differ. During ED presentation, OSS users had better preserved left ventricular ejection fraction on echocardiogram (P = .04) and lower length of hospital stay by a mean 1.7 days (P = .02). CONCLUSIONS: OSS is used by a portion of infants with SVT. It is associated with more frequent phone calls and ED visits but lower length of stay and better-preserved cardiac function upon presentation.

Exploring the Hidden Complexity: Entropy Analysis in Pulse Oximetry of Female Athletes.

This study examines the relationship between physiological complexity, as measured by Approximate Entropy (ApEn) and Sample Entropy (SampEn), and fitness levels in female athletes. Our focus is on their association with maximal oxygen consumption (VO2,max). Our findings reveal a complex relationship between entropy metrics and fitness levels, indicating that higher fitness typically, though not invariably, correlates with greater entropy in physiological time series data; however, this is not consistent for all individuals. For Heart Rate (HR), entropy measures suggest stable patterns across fitness categories, while pulse oximetry (SpO2) data shows greater variability. For instance, the medium fitness group displayed an ApEn(HR) = 0.57±0.13 with a coefficient of variation (CV) of 22.17 and ApEn(SpO2) = 0.96±0.49 with a CV of 46.08%, compared to the excellent fitness group with ApEn(HR) = 0.60±0.09 with a CV of 15.19% and ApEn(SpO2) =0.85±0.42 with a CV of 49.46%, suggesting broader physiological responses among more fit individuals. The larger standard deviations and CVs for SpO2 entropy may indicate the body's proficient oxygen utilization at higher levels of physical demand. Our findings advocate for combining entropy metrics with wearable sensor technology for improved biomedical analysis and personalized healthcare.

Preterm Infants off Positive Pressure Respiratory Support Have a Higher Incidence of Occult Cerebral Hypoxia.

OBJECTIVE: To use cerebral near-infrared spectroscopy (NIRS) to quantify occult cerebral hypoxia across respiratory support modes in preterm infants. STUDY DESIGN: In this prospective, longitudinal, observational study, infants ≤32 weeks gestation underwent serial pulse oximetry (oxygen saturation [SpO2]) and cerebral NIRS monitoring (4-6 hours per session) following a standardized recording schedule (daily for 2 weeks, every other day for 2 weeks, then weekly until 35 weeks corrected gestational age). Four calculations were made: median cerebral saturation, median cerebral hypoxia burden (proportion of NIRS samples below the hypoxia threshold [<67%]), median systemic saturation, and median systemic hypoxia burden (proportion of SpO2 samples below the desaturation threshold [<85%]). During each recording session, respiratory support mode was noted (room air, low-flow nasal cannula, high-flow nasal cannula, noninvasive positive pressure ventilation, continuous positive airway pressure, and invasive ventilation). RESULTS: There were 1013 recording sessions made from 174 infants with a median length of 6.9 hours. Although the systemic (SpO2) hypoxia burden was significantly greater for infants on the highest respiratory support (invasive and noninvasive positive pressure ventilation), the cerebral hypoxia burden was significantly greater during recording sessions made on the lowest respiratory support (8% for room air; 29% for low-flow nasal cannula). CONCLUSIONS: Premature infants on the highest levels of respiratory support have less cerebral hypoxia than those on lower respiratory support. These results raise concern about unrecognized cerebral hypoxia during lower acuity periods of neonatal intensive care unit hospitalization and adverse outcomes.

Does irradiation of the tooth structure interfere with oxygen saturation measured by pulse oximetry?-An ex vivo laboratorial study.

The effect of tooth structure subjected to ionising radiation on oxygen saturation levels (SpO2 ) measured by pulse oximetry was investigated. Fifty-four extracted human third molars were sectioned mesiodistally. Pulse oximeter diodes were placed in prefabricated silicone moulds, secured on a vise with tooth surfaces placed between the diodes and the participant's finger, and SpO2 levels were measured. After that, the tooth surfaces were subjected to ionising radiation in fractionated doses of up to 70 Gy, and SpO2 was measured according to the protocol described. The Kolmogorov-Smirnov test was used for the analysis of normality of the quantitative variables, and Student's t-test compared mean SpO2 levels before and after irradiation. Mean SpO2 after irradiation was 94.6 ± 0.9%, without a statistically significant difference from SpO2 before irradiation, which was 94.7 ± 0.6%. Irradiation of the tooth structure did not interfere with SpO2 levels measured by pulse oximetry.

Oximetría de pulso y toma de decisión

Introducción: La enfermad producida por el COVID-19 constituye un problema sanitario mundial. La identificación precoz de las manifestaciones clínicas y del compromiso respiratorio resulta vital para minimizar las complicaciones de la enfermedad; en este sentido, la utilización del oxímetro de pulso constituye una alternativa interesante. Objetivo: Describir las ventajas aportadas por la utilización del oxímetro de pulso en la toma de decisión de pacientes para acudir oportunamente a solicitar atención médica. Métodos: Investigación básica, diseño descriptivo y retrospectivo. Universo constituido por 348 pacientes con diagnóstico de COVID-19 y la muestra por 184 casos. Se determinó frecuencia de complicaciones e influencia del uso de oxímetro de pulso en la toma de decisiones. Se utilizó prueba no paramétrica de Odd Ratio y Fisher exacta para identificar rango de ocurrencia. Resultados: promedio de edad de 54,47 años con predominio de pacientes femeninas (60,33 %) y con comorbilidades asociadas (66,85 %). El 25,00 % de los pacientes presentó afectación respiratoria como complicación de la OVID-19. El 47,83 % de los pacientes con complicaciones uso oxímetro de pulso, aunque solo el 27,27 % acudió tempranamente a consulta, pero si en el 90,91 % la decisión de asistir a servicio de urgencia estuvo influenciada por el uso del oxímetro de punto y sus resultados. Conclusiones: La oximetría de pulso ayudó a los pacientes a tomar la decisión de acudir en busca de atención médica. Puede considerarse el monitoreo de la saturación de oxígeno como una acción positiva en torno a la sospecha clínica de afección respiratoria severa.

Introduction: The disease caused by COVID-19 constitutes a global health problem. The early identification of clinical manifestations and respiratory compromise is vital to minimize the complications of the disease; in this sense, the use of the pulse oximeter constitutes an interesting alternative. Objective: To describe the advantages provided by the use of the pulse oximeter in the decision-making of patients to go in a timely manner to request medical attention. Methods: Basic research, descriptive and retrospective design. Universe made up of 348 patients diagnosed with COVID-19 and the sample of 184 cases. The frequency of complications and the influence of the use of pulse oximeter in decision making were determined. Non-parametric Odd Ratio and Fisher's exact tests were used to identify the range of occurrence. Results: average age of 54.47 years with a predominance of female patients (60.33 %) and with associated comorbidities (66.85 %). 25.00 % of the patients presented respiratory involvement as a complication of OVID-19. 47.83 % of the patients with complications used a pulse oximeter, although only 27.27 % attended the consultation early, but in 90.91 % the decision to attend the emergency service was influenced by the use of the oximeter point and its results. Conclusions: Pulse oximetry helped patients make the decision to seek medical attention. Oxygen saturation monitoring can be considered as a positive action around the clinical suspicion of severe respiratory disease.

Parental Ability to Assess Pediatric Vital Signs.

OBJECTIVE: To evaluate parents' ability to accurately assess their child's heart and respiratory rates (RRs) in the context of potential utility for telehealth visits. STUDY DESIGN: In this controlled study of 203 child-parent pairs, parents measured their child's heart rate (HR) using 4 methods: palpation, auscultation, and 2 photoplethysmographic smartphone applications. Parents measured RR by inspecting the child and tapping the smartphone application. The gold standards were electrocardiogram for the HR and the child's breaths measured by a health care professional for 60 seconds for the RR. We plotted the measurements using a Bland-Altman plot with 95% limits of agreement. RESULTS: Parents underestimated HR by palpation with a calculated bias of -18 beats per minute (bpm) (SD, 19), with limits of agreement ranging from -56 to 19 bpm. Parents overestimated and underestimated HR by auscultation with limits of agreement ranging from -53 to 46 bpm. Smartphone applications did not improve the accuracy of measurements. The accuracy of parental RR measurements was low. For young children, bias was -0.8 breaths per minute (brpm) (SD, 9.8) with limits of agreement from -20 to 19 brpm, and for older children, bias was 0.9 brpm (SD 7.4) with limits of agreement from 6 to 15 brpm. The sensitivity of parental subjective opinion to recognize accelerated RR was 37% (95% CI, 25%-51%). CONCLUSION: Parents were not able to assess their child's RR or HR accurately. Digital remote assessment of children should not rely on parental measurements of vital signs.

Medición de los niveles de lactato sérico y frecuencia cardiaca en caninos (Canis lupus familiaris) braquicefálicos, mesocefálicos y dolicocefálicos sometidos a prueba de esfuerzo en trotadora motorizada / Measurement of serum lactate levels and heart rate in canines (Canis lupus familiaris) Brachycephalic, Mesocephalic and Dolichocephalic submitted to a stress test on a motorized treadmill

RESUMEN Se analizaron los niveles de lactato sérico y de frecuencia cardiaca (FC) en 15 perros clinicamente sanos que fueron sometidos a pruebas de esfuerzo en trotadora motorizada, buscando verificar un grado de fatiga muscular frente a una prueba de esfuerzo intenso. Se consideraron pacientes con morfologia craneana de tipo braquicefálico, mesocefálico y dolicocefálico. Las mediciones séricas de lactato fueron conseguidas por medio de un medidor portátil, mientras que las frecuencias cardiacas se obtuvieron a través de un oximetro portátil a los tiempos 0, 10, 20 y 30 minutos, en los diferentes momentos de esfuerzo fisico en la trotadora motorizada, la cual fue adaptada en su inclinación en 15% y a un máximo de velocidad de 10 km/h. Las medias de los niveles séricos entre perros mesocefálicos y dolicocefálicos fueron significativas, a diferencia de los perros braquicefálicos los cuales resultaron no significativos. Las medias de las frecuencias cardiacas no tuvieron diferencia significativa bajo un 95% de confianza.

ABSTRACT Serum lactate and heart rate (HR) levels were analyzed in 15 clinically healthy dogs that were subjected to stress tests on a motorized treadmill, seeking to verify a degree of muscle fatigue compared to an intense exercise test. Patients with brachycephalic, mesocephalic and dolichocephalic type cranial morphology were considered. Serum lactate measurements were procured by means of a portable meter, while heart rates were obtained through a portable oximeter at the times 0, 10, 20, and 30 minutes at different moments of physical effort on the motorized treadmill, which was adapted in its inclination by 15% and at a maximum speed of 10 km/h. Mean serum levels between mesocephalic and dolichocephalic dogs were significant, unlike brachycephalic dogs, which were not significant. The mean heart rates did not have a significant difference under 95% confidence.

Children with Congenital Central Hypoventilation Syndrome Do Not Wake up to Ventilator Alarms.

PURPOSE: Congenital Central Hypoventilation Syndrome (CCHS) requires lifelong ventilatory support during sleep. Subjects with CCHS are vulnerable to sleep disturbances associated with treatments, monitoring alarms, and care they receive. We hypothesized that sleep would be disrupted in patients  with CCHS due to ventilatory support and other treatments at night. METHODS: An anonymous survey of patients with CCHS, age up to 17 years was conducted through REDCAP. Subjects were recruited in person, by flyer, email, and social media. Data collected included demographics, PHOX2B genotype, ventilatory support, treatments, nursing, and sleep parameters. RESULTS: We received 23 responses (35% female, 8.1 years ± 5.6). PHOX2B genotypes were 20/24 PARM (2), 20/25 PARM (4), 20/26 PARM (2), 20/27 PARM (9), ≥ 20/28 PARM (2), and NPARM (2). Two subjects did not indicate the PHOX2B genotype. 13/23 were ventilated by PPV via tracheostomy, 7 by NIPPV, 2 by diaphragm pacing, and 1 did not indicate. Additional treatments received at night included suctioning (9), aerosol (1), G-tube feeding (2), and none (11). Only 9 received nursing at night. 13 used pulse oximetry for monitoring, and 9 used both pulse oximetry and end tidal CO2 monitor. 17/23 rarely woke up due to ventilator or monitor alarms. 11/23 usually or sometimes woke up at least once a night; only 2/11 woke up due to alarms. 5/17 who rarely woke up to the alarms had night nursing. CONCLUSION: Most subjects with CCHS did not awaken to ventilator or monitoring alarms and a majority of these patients did not have nighttime nursing. (Mathur et al. in Sleep 43(Supplement_1):A333, 2020).

Prediction of Extubation Failure in COVID-19.

BACKGROUND: [Formula: see text] may be a reliable noninvasive alternative to the [Formula: see text] index. Furthermore, the ROX index (ie, the ratio of [Formula: see text] to breathing frequency) has been validated to predict high-flow nasal cannula failure in subjects under spontaneous breathing. However, these indices have not been tested in subjects with COVID-19 receiving invasive mechanical ventilation. This study aims to verify the correlation between both the ROX index and [Formula: see text] with [Formula: see text] and the ratio of [Formula: see text] to breathing frequency, and to determine the accuracy of the indices that use [Formula: see text] for the prediction of extubation failure in subjects with COVID-19. METHODS: A prospective cohort study was conducted from May 15, 2020, to June 15, 2020, with subjects with COVID-19 on invasive mechanical ventilation. Indices using [Formula: see text] in the formula were compared to those using [Formula: see text]. Additionally, the performance of the indices in predicting extubation failure was evaluated. RESULTS: This study included 69 subjects age 64.8 ± 14.6 y. There were no differences between the median values of the indices, including between the ROX index and [Formula: see text] to breathing frequency (P = .40) or between [Formula: see text] and [Formula: see text] (P = .83). When comparing the ROX index with the [Formula: see text] index to breathing frequency, they were found to be strongly correlated (R2 = 0.75 [95% CI 0.6763-0.8152], P < .001). The comparison of [Formula: see text] with [Formula: see text] revealed R2 = 0.70 (95% CI 0.563-0.749, P < .001). The area under the receiver operating characteristic curve for the ROX index to determine extubation failure was 0.74 (P = .01), whereas for [Formula: see text] it was 0.78 (P < .001). CONCLUSIONS: The indices presented a good correlation in subjects with COVID-19 on invasive mechanical ventilation, and both the ROX index and [Formula: see text] can discriminate extubation failure in this population.

Diagnostic accuracy of dental pulse oximeter with customized sensor holder, thermal test and electric pulp test for the evaluation of pulp vitality: an in vivo study / Precisão diagnóstica do oxímetro de pulso odontológico com suporte de sensor personalizado, teste térmico e teste elétrico da polpa para avaliação da vitalidade pulpar: um estudo in vivo

Background: the efficiency of the diagnostic aids plays an important role in the treatment plan. This study aims to assess the diagnostic accuracy of dental pulse oximeter with a customized sensor holder, thermal test and electric pulp tester in assessing the actual pulp status and to evaluate the oxygen saturation level in control healthy teeth, non-vital and teeth with irreversible pulpitis. Material and methods: thirty-seven single canal teeth requiring endodontic therapy were included in the study. The selected teeth were tested with dental pulse oximeter, electric pulp test, cold spray, and heated gutta percha stick. Between each test a time lag of 2 minutes was allowed for the central sensitization to occur. Three blinded operators were involved in the study. The actual status of the pulp was evaluated after the initiation of endodontic treatment, by direct visual examination of the accessed cavity. The data was statistically analysed using (ANOVA) Analysis of Variance and Post-hoc Tukey test. Results: sensitivity of pulse oximeter, heat test, cold and electric pulp test, was 100, 25, 50, and 12, respectively. The specificity of these tests was 100, 72 81, and 77, respectively. The ANOVA showed that there was statistical difference between all the groups (p=0.0005). Post-Hoc Tukey revealed that there was statistical difference among all the groups, nonvital group (p=0.0005), control group (p=0.01) and for irreversible pulpitis (p=0.01). The overall diagnostic accuracy of pulse oximeter was 100% followed by cold test 66%, heat test to be 49% and electric pulp test to be 45%. Conclusion: the custom-made holder used in the present study aided in providing accurate response for pulp vitality testing. In this study the diagnostic accuracy was high with dental pulse oximeter followed by cold, heat and the least was electric pulp tester in different pulpal conditions. (AU)

Fundamentação: a eficiência dos meios de diagnóstico desempenha um papel importante no plano de tratamento. Este estudo tem como objetivo avaliar a precisão diagnóstica do oxímetro de pulso odontológico com um suporte de sensor personalizado, teste térmico e testador de polpa elétrico na avaliação da condição pulpar e na avaliação do nível de saturação de oxigênio em dentes controle saudáveis, não vitais e dentes com pulpite irreversível. Material e métodos: trinta e sete dentes de canal único que necessitavam de terapia endodôntica foram incluídos no estudo. Os dentes selecionados foram testados com oxímetro de pulso, teste pulpar elétrico, spray frio e bastão de guta-percha aquecido. Entre cada teste, foi permitido um intervalo de tempo de 2 minutos para a sensibilização central ocorrer. Três operadores cegos foram envolvidos no estudo. A condição real da polpa foi avaliada após o início do tratamento endodôntico, por meio de exame visual direto da cavidade de acesso. Os dados foram analisados estatisticamente pelo teste de Análise de Variância (ANOVA) e pelo teste Post-hoc de Tukey. Resultados: a sensibilidade do oxímetro de pulso, teste de calor, de frio e teste pulpar elétrico foi de 100, 25, 50 e 12, respectivamente. A especificidade desses testes foi de 100, 72 81 e 77, respectivamente. O teste de ANOVA mostrou que houve diferença estatística entre todos os grupos (p = 0,0005). O teste Post-Hoc de Tukey revelou que houve diferença estatística entre todos os grupos, grupo não-vital (p = 0,0005), grupo controle (p = 0,01) e pulpite irreversível (p = 0,01). A precisão diagnóstica geral do oxímetro de pulso foi de 100%, seguida pelo teste a frio de 66%, o teste de calor a 49% e o teste pulpar elétrico a 45%. Conclusão: o suporte personalizado utilizado no presente estudo ajudou a fornecer uma resposta precisa para o teste de vitalidade pulpar. Neste estudo, a precisão diagnóstica foi alta com o oxímetro de pulso dental, seguido do teste com frio e calor, sendo o teste elétrico o menos eficaz nas diferentes condições pulpares testadas.(AU)

Validación de cinco pulsioxímetros / Validation of five pulse oximeters

Resumen: ANTECEDENTES: la pulsioxímetria estima la saturación arterial de oxígeno mediante la absorción de un haz de luz infrarroja por la oxihemoglobina. OBJETIVO: determinar la validez y la confiabilidad interinstrumento de cinco pulsioxímetros comúnmente usados en la práctica clínica. MATERIAL Y MÉTODO: estudio transversal, analítico, realizado del 1 de enero de 2015 al 30 de octubre de 2016, en el que se incluyeron pacientes mayores de 18 años de edad, con línea arterial para toma de gasometría y se midió simultáneamente la saturación de oxígeno con cinco pulsioxímetros de uso habitual. Se determinaron medianas y porcentajes de los cinco pulsioxímetros entre sí mediante prueba de Friedman. RESULTADOS: se incluyeron 101 pacientes, 63 hombres y 38 mujeres. Se encontró similitud en las mediciones realizadas por cada pulsioxímetro con p = 0.08; todos los oxímetros se correlacionaron de manera positiva contra la prueba patrón de referencia (correlación de Pearson). Oxímetro 1: r = 0.90; oxímetro 2: r = 0.64; oxímetro 3: r = 0.57; oxímetro 4: r = 0.84 y oxímetro 5: r = 0.89; el área bajo la curva mostró oxímetro 1 (0.89), oxímetro 2 (0.88), oxímetro 3 (0.87), oxímetro 4 (0.83), oxímetro 5 (0.85) con p < 0.05. CONCLUSIONES: el pulsioxímetro número 1 muestra el mejor rendimiento comparado con la gasometría. Al comparar los oxímetros entre sí el rendimiento es igual.

Abstract: BACKGROUND: Pulse oximetry estimates the arterial oxygen saturation by absorption of an infrared light beam by oxyhemoglobin. OBJECTIVE: To determine the intraclass validity and reliability of five pulse oximeters commonly used in clinical practice. MATERIAL AND METHOD: A cross-sectional analytical study was done from January 1st 2015 to October 30 2016, including patients over 18 years old, with arterial line for blood gas sample and simultaneously oxygen saturation was measured with 5 pulse oximeters commonly used. Medians and percentages of the 5 pulse oximeters were determined by Friedman's test RESULTS: There were included 101 patients, 63 men and 38 women, with similarity in the measurements performed by each pulse oximeter with p = 0.08; all oximeters were positively correlated against the standard gold test (Pearson's correlation). Oximeter 1: r = 0.90; oximeter 2: r = 0.64; oximeter 3: r = 0.57; oximeter 4: r = 0.84 and oximeter 5: r = 0.89. The area under the curve showed oximeter 1 (0.89), oximeter 2 (0.88), oximeter 3 (0.87), oximeter 4 (0.83), oximeter 5 (0.85) with p < 0.05. CONCLUSIONS: The pulse oximeter number 1 shows a better performance when compared to the gasometry. When the oximeters are compared to each other the performance is the same.

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.

Assessment of oxygen saturation in dental pulp of permanent teeth with periodontal disease.

INTRODUCTION: In individuals with periodontal disease, dental pulp status should be determined before a treatment plan is made. Pulse oximeters are promising diagnostic tools to evaluate pulp vascularization. This study used pulse oximetry to determine the level of oxygen saturation in dental pulp of intact permanent teeth with periodontal attachment loss (PAL) and gingival recession (GR) and to evaluate the correlation between periodontal disease and level of oxygen saturation in the pulp. METHODS: This study included 67 anterior teeth of 35 patients; all teeth showed intact crowns, PAL, a periodontal pocket (PP), and GR. The teeth underwent periodontal examination, cold and electric pulp testing, and pulse oximetry measurements. The Pearson correlation coefficient and a linear regression coefficient were calculated to evaluate the degree of correlation between periodontal disease markers (PAL, PP, and GR) and the level of oxygen saturation in dental pulp. These tests also evaluated possible associations between oxygen saturation and cold and electric pulp testing. RESULTS: PAL, PP, and GR had negative correlations with oxygen saturation in dental pulp. Conversely, no statistically significant association was found between oxygen saturation in dental pulp and the response to electric sensibility testing. CONCLUSIONS: Oxygen saturation was lower in the pulp of permanent teeth with PAL, PP, and GR, indicating that periodontal disease correlates with the level of oxygen saturation in the pulp.

A randomised controlled trial of an automated oxygen delivery algorithm for preterm neonates receiving supplemental oxygen without mechanical ventilation.

AIM: Providing consistent levels of oxygen saturation (SpO2 ) for infants in neonatal intensive care units is not easy. This study explored how effectively the Auto-Mixer(®) algorithm automatically adjusted fraction of inspired oxygen (FiO2 ) levels to maintain SpO2 within an intended range in extremely low birth weight infants receiving supplemental oxygen without mechanical ventilation. METHODS: Twenty extremely low birth weight infants were randomly assigned to the Auto-Mixer(®) group or the manual intervention group and studied for 12 h. The SpO2 target was 85-93%, and the outcomes were the percentage of time SpO2 was within target, SpO2 variability, SpO2 >95%, oxygen received and manual interventions. RESULTS: The percentage of time within intended SpO2 was 58 ± 4% in the Auto-Mixer(®) group and 33.7 ± 4.7% in the manual group, SpO2 >95% was 26.5% vs 54.8%, average SpO2 and FiO2 were 89.8% vs 92.2% and 37% vs 44.1%, and manual interventions were 0 vs 80 (p < 0.05). Brief periods of SpO2  < 85% occurred more frequently in the Auto-Mixer(®) group. CONCLUSION: The Auto-Mixer(®) effectively increased the percentage of time that SpO2 was within the intended target range and decreased the time with high SpO2 in spontaneously breathing extremely low birth weight infants receiving supplemental oxygen.

Precisión y exactitud de un oxímetro de pulso "de bolsillo" en la ciudad de México / Precision and accuracy of "a pocket"pulse oximeter in Mexico City

Background. Pulse oximeters are frequently used in the clinical practice and we must known their precision and accuracy. The objective was to evaluate the precision and accuracy of a "pocket" pulse oximeter at an altitude of 2,240 m above sea level. Methods. We tested miniature pulse oximeters (Onyx 9,500, Nonin Finger Pulse Oximeter) in 96 patients sent to the pulmonary laboratory for an arterial blood sample. Patients were tested with 5 pulse oximeters placed in each of the fingers of the hand oposite to that used for the arterial puncture. The gold standard was the oxygen saturation of the arterial blood sample. Results. Blood samples had SaO2 of 87.2 ± 11.0 (between 42.2 and 97.9%). Pulse oximeters had a mean error of 0.28 ± 3.1%. SaO2 - (1.204 x SpO2) - 17.45966 (r = 0.92, p < 0.0001). Intraclass correlation coefficient between each of five pulse oximeters against the arterial blood standard ranged between 0.87 and 0.99. HbCO (2.4 ± 0.6) did not affect the accuracy. Conclusions. The miniature oximeter Nonin is precise and accurate at 2,240 m of altitude. The observed levels of HbCO did not affect the performance of the equipment. The oximeter good performance, small size and low cost enhances its clinical usefulness.

Introducción. Los oxímetros de pulso son ampliamente utilizados en la práctica clínica y su precisión y exactitud deben conocerse especialmente en altitudes moderadas como en la ciudad de México. El objetivo principal fue evaluar la precisión y exactitud de un oxímetro de pulso "de bolsillo" (Onyx 9500 de Nonin®) en la ciudad de México. Métodos. Se realizaron mediciones de la saturación de oxígeno estimada por el oxímetro de pulso (SpO2) y se compararon contra la medida espectrofotométricamente en sangre arterial (SaO2) en 96 pacientes que acudieron al laboratorio de fisiología pulmonar del Instituto Nacional de Enfermedades Respiratorias. A cada paciente se le colocaron cinco oxímetros de pulso en los dedos de una mano obteniéndose un promedio de SpO2 para cada uno de los oxímetros y para los cinco oxímetros a la vez, mediciones que se compararon de manera simultánea contra el estándar. Resultados. Las muestras sanguíneas de los 96 pacientes que participaron tuvieron una SaO2 de 87.2 ± 11.0 (entre 42.2-97.9%). Los oxímetros (promedio de los cinco) tuvieron un error de medición promedio de 0.28 ± 3.1%. SaO2 = (1.204 x SpO2) - 17.45966 (r = 0.92, p < 0.0001). Los coeficientes de correlación intraclase que se obtuvieron al comparar los oxímetros entre sí y contra el estándar (SaO2) estuvieron entre 0.87 y 0.99. El nivel de carboxihemoglobina (HbCO) fue de 2.4 ± 0.6% y no afectó significativamente la exactitud del oxímetro. Conclusiones. El oxímetro digital de pulso "de bolsillo" es preciso y exacto en la estimación de la SaO2 a 2,240 metros de altitud. Los niveles observados de HbCO (2.4%) no afectaron su exactitud. Se observó un adecuado desempeño del oxímetro digital de pulso en la ciudad de México.