Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.012
Filtrar
1.
Undersea Hyperb Med ; 48(1): 33-42, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33648031

RESUMO

Introduction: This study aimed to assess the capability of a pulse CO-oximeter to continuously monitor carboxyhemoglobin (COHb) during hyperbaric oxygen (HBO2) therapy. We estimated limits of agreement (LOA) between blood gas analysis and pulse CO-oximeter for COHb during HBO2 therapy in patients suffering from acute CO poisoning. Furthermore, we did a medicotechnical evaluation of the pulse CO-oximeter in hyperbaric conditions. Methods: We conducted a prospective, non-clinical, observational study in which we included n=10 patients with acute CO poisoning referred for HBO2 therapy. We did five repeated measurements of COHb for each patient during the HBO2 therapy. Bland-Altman analysis for multiple observations per individual was used to assess the agreement. The a priori LOA was ±6% for COHb. For the medicotechnical evaluation continuous measurements were obtained throughout each complete HBO2 therapy. The measurements were visually inspected and evaluated. Results: The Bland-Altman analysis showed that the pulse CO-oximeter overestimated COHb by 2.9 % [±1.0%] and the LOA was ±7.3% [±1.8%]. The continuous measurements by pulse CO-oximetry showed fluctuating levels of COHb and summarized saturations reached levels above 100%. Measurements were not affected by changes in pressure. Conclusion: To our knowledge, this study is the first to assess LOA and demonstrate use of a non-invasive method to measure COHb during HBO2 therapy. The pulse CO-oximeter performed within the manufactures reported LOA (±6%) despite hyperbaric conditions and was unaffected by changes in pressure. However, summarized saturations reached levels above 100%.


Assuntos
Intoxicação por Monóxido de Carbono/sangue , Intoxicação por Monóxido de Carbono/terapia , Carboxihemoglobina/análise , Oxigenação Hiperbárica , Oximetria/instrumentação , Adulto , Gasometria , Dinamarca , Feminino , Meia-Vida , Humanos , Masculino , Oximetria/métodos , Estudos Prospectivos , Pigmentação da Pele
2.
J Vis Exp ; (162)2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32894267

RESUMO

Near infrared spectroscopy (NIRS) calculates regional tissue oxygenation (rSO2) using the different absorption spectra of oxygenated and deoxygenated hemoglobin molecules. A probe placed on the skin emits light that is absorbed, scattered, and reflected by the underlying tissue. Detectors in the probe sense the amount of reflected light: this reflects the organ-specific ratio of oxygen supply and consumption - independent of pulsatile flow. Modern devices enable the simultaneous monitoring at different body sites. A rise or dip in the rSO2 curve visualizes changes in oxygen supply or demand before vital signs indicate them. The evolution of rSO2 values in relation to the starting point is more important for interpretation than are absolute values. A routine clinical application of NIRS is the surveillance of somatic and cerebral oxygenation during and after cardiac surgery. It is also administered in preterm infants at risk for necrotizing enterocolitis, newborns with hypoxic ischemic encephalopathy and a potential risk of impaired tissue oxygenation. In the future, NIRS could be increasingly used in multimodal neuromonitoring, or applied to monitor patients with other conditions (e.g., after resuscitation or traumatic brain injury).


Assuntos
Estado Terminal , Oximetria/métodos , Espectroscopia de Luz Próxima ao Infravermelho , Criança , Humanos , Lactente , Recém-Nascido , Masculino , Oximetria/instrumentação , Consumo de Oxigênio/fisiologia , Oxiemoglobinas/análise
3.
Sensors (Basel) ; 20(17)2020 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-32872310

RESUMO

The non-invasive estimation of blood oxygen saturation (SpO2) by pulse oximetry is of vital importance clinically, from the detection of sleep apnea to the recent ambulatory monitoring of hypoxemia in the delayed post-infective phase of COVID-19. In this proof of concept study, we set out to establish the feasibility of SpO2 measurement from the ear canal as a convenient site for long term monitoring, and perform a comprehensive comparison with the right index finger-the conventional clinical measurement site. During resting blood oxygen saturation estimation, we found a root mean square difference of 1.47% between the two measurement sites, with a mean difference of 0.23% higher SpO2 in the right ear canal. Using breath holds, we observe the known phenomena of time delay between central circulation and peripheral circulation with a mean delay between the ear and finger of 12.4 s across all subjects. Furthermore, we document the lower photoplethysmogram amplitude from the ear canal and suggest ways to mitigate this issue. In conjunction with the well-known robustness to temperature induced vasoconstriction, this makes conclusive evidence for in-ear SpO2 monitoring being both convenient and superior to conventional finger measurement for continuous non-intrusive monitoring in both clinical and everyday-life settings.


Assuntos
Meato Acústico Externo , Hipóxia/diagnóstico , Monitorização Fisiológica/instrumentação , Oximetria/instrumentação , Fotopletismografia/instrumentação , Dispositivos Eletrônicos Vestíveis , Adulto , Betacoronavirus/fisiologia , Infecções por Coronavirus/sangue , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/terapia , Estudos de Equivalência como Asunto , Estudos de Viabilidade , Feminino , Dedos , Humanos , Hipóxia/sangue , Masculino , Monitorização Fisiológica/métodos , Oximetria/métodos , Oxigênio/análise , Oxigênio/sangue , Pandemias , Fotopletismografia/métodos , Pneumonia Viral/sangue , Pneumonia Viral/diagnóstico , Pneumonia Viral/terapia , Adulto Jovem
4.
Pediatrics ; 146(3)2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32848028

RESUMO

BACKGROUND AND OBJECTIVES: Preterm infants with necrotizing enterocolitis (NEC) are known to have worse neurodevelopmental outcomes, but there is no substantial evidence to support an underlying pathophysiology. We aimed to examine whether cerebral oxygenation differs in those infants who develop NEC compared to cerebral oxygenation in those who do not. METHODS: We examined 48 infants <30 weeks' gestation admitted to a tertiary level NICU from October 2016 to May 2018. Infants with birth weight less than or equal to the second percentile, abnormal antenatal dopplers or twin-to-twin-transfusion-syndrome were excluded. Cerebral oximetry measurements were performed by using a near-infrared spectroscopy (NIRS) monitor weekly for 60 minutes, allowing measurement of cerebral tissue oxygenation index from the first week of life to 36 weeks postconceptional age. Weekly clinical status was also recorded. NEC was defined as greater than or equal to Bell stage 2. RESULTS: The median birth weight was 884 g (range of 460-1600 g), the median weeks' gestational age was 26 + 3/7 (23 + 0/7 to 29 + 6/7), and 52% were girls. In total, 276 NIRS measurements were completed, and 7 infants developed NEC. NIRS measurements from 1 infant with NEC and 4 infants without NEC who developed hemorrhagic parenchymal infarcts were excluded from analysis. Infants who developed NEC had significantly lower cerebral tissue oxygenation index than those who did not (P = .011), even when adjusted for confounders, including gestational age, birth weight, patent ductus arteriosus, enteral feeds, sex, ethnicity, and hemoglobin. CONCLUSIONS: Infants with NEC have significantly lower cerebral tissue oxygenation throughout their neonatal intensive care stay in comparison with those who did not develop NEC. This is a novel finding and could explain their worse neurodevelopmental outcome.


Assuntos
Encéfalo/metabolismo , Enterocolite Necrosante/metabolismo , Consumo de Oxigênio/fisiologia , Antibioticoprofilaxia , Permeabilidade do Canal Arterial/diagnóstico por imagem , Enterocolite Necrosante/etiologia , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Oximetria/instrumentação , Oximetria/métodos , Estudos Prospectivos , Espectroscopia de Luz Próxima ao Infravermelho , Fatores de Tempo
5.
Br J Anaesth ; 125(5): 826-834, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32682554

RESUMO

BACKGROUND: We compared anaesthetists' ability to identify haemoglobin oxygen saturation (SpO2) levels using two auditory displays: one based on a standard pulse oximeter display (varying pitch plus alarm) and the other enhanced with additional sound properties (varying pitch plus tremolo and acoustic brightness) to differentiate SpO2 ranges. METHODS: In a counter-balanced crossover study in a simulator, 20 experienced anaesthetists supervised a junior colleague (an actor) managing two airway surgery scenarios: once while using the enhanced auditory display and once while using a standard auditory display. Participants were distracted with other tasks such as paperwork and workplace interruptions, but were required to identify when SpO2 transitioned between pre-set ranges (target, low, critical) and when other vital signs transitioned out of a target range. They also identified the range once a transition had occurred. Visual displays were available for all monitored vital signs, but the numerical value for SpO2 was excluded. RESULTS: Participants were more accurate and faster at detecting transitions to and from the target SpO2 range when using the enhanced display (100.0%, 3.3 s) than when using the standard display plus alarm (73.2%, 27.4 s) (P<0.001 and P=0.004, respectively). They were also more accurate at identifying the SpO2 range once a transition had occurred when using the enhanced display (100.0%) than when using the standard display plus alarm (57.1%; P<0.001). CONCLUSIONS: The enhanced auditory display helps anaesthetists judge SpO2 levels more effectively than current auditory displays and may facilitate 'eyes-free' monitoring.


Assuntos
Apresentação de Dados , Oximetria/instrumentação , Estimulação Acústica , Adulto , Anestesiologistas , Alarmes Clínicos , Estudos Cross-Over , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Salas Cirúrgicas/organização & administração , Oxigênio/sangue , Inquéritos e Questionários , Sinais Vitais
6.
s.l; IETSI; 2 jul. 2020.
Não convencional em Espanhol | LILACS, BRISA/RedTESA | ID: biblio-1104045

RESUMO

INTRODUCCIÓN. La actual pandemia de COVID-19 constituye un reto sin precedentes para los sistemas de salud a nivel mundial. A medida que los médicos brindan atención cada vez a más pacientes con COVID-19 se ha notado y descrito en la literatura un fenómeno conocido extraoficialmente como "hipoxemia silenciosa" o "hipoxemia feliz". Este fenómeno poco común hace referencia a una disonancia entre los valores de saturación de oxígeno en sangre y la ausencia de síntomas relacionados con la dificultad respiratoria (taquipnea o respiración rápida, disnea, tiraje intercostal, fatiga, sofocación, hambre de aire, entre otros). En otras palabras, a pesar de no experimentar ningún síntoma o presentar únicamente síntomas generales leves (dolor de cabeza, tos leve, dolor de garganta, pérdida del olfato, entre otros), llama la atención que algunos pacientes no presenten síntomas de dificultad respiratoria notables a pesar de presentar bajos niveles de oxígeno en sangre (hipoxemia) (Tobin, Laghi, and Jubran 2020; Couzin-Frankel 2020). Inclusive, algunos autores han repo


Assuntos
Humanos , Pneumonia Viral/terapia , Oximetria/instrumentação , Infecções por Coronavirus/terapia , Avaliação da Tecnologia Biomédica , Avaliação em Saúde , Fatores de Risco
8.
Neuquén; s.n; jun. 2020.
Não convencional em Espanhol | LILACS, BRISA/RedTESA | ID: biblio-1116538

RESUMO

CONTEXTO: El diagnóstico y monitoreo del nivel de oxígeno1 (O2) en el organismo resulta de gran importancia en la atención de salud en diversos casos. La insuficiencia respiratoria hipoxémica es la primera causa de hospitalización en pediatría, el control estricto de la oxemia es mandatorio en pacientes neonatos prematuros, debido al riesgo de daños retinianos ante la exposición prolongada a concentraciones elevadas de oxígeno, también es utilizada la evaluación de la saturación de oxígeno en los miembros para descartar ciertas cardiopatías congénitas. En los pacientes críticos con necesidad de ventilación mecánica u otras modalidades, la determinación del oxígeno en sangre resulta un parámetro imprescindible para monitorear la calidad del tratamiento de soporte. En estos pacientes puede realizarse por determinación directa en catéteres arteriales, o indirectamente por métodos de saturometría de pulso. La evaluación de la hipoxemia se realiza con medición de gases arteriales y a través de metodologías no invasivas con saturometría de pulso, sin embargo, esta medición puede verse afectada por diversos factores como la intensidad de la luz ambiental, pigmentación de la piel, perfusión tisular, concentración de hemoglobina y otros. La cianosis es un signo tardío de hipoxemia apareciendo habitualmente con saturación de oxígeno menor a 75%. La oximetría de pulso es una herramienta que permite medir en forma no invasiva la saturación de oxígeno de la hemoglobina y ha significado una revolución en el manejo y monitorización de los pacientes con insuficiencia respiratoria. Se caracteriza por ser simple, no invasiva y razonablemente confiable en la mayoría de las circunstancias clínicas.En los últimos 15 años los avances tecnológicos y la competencia entre marcas y modelos van favoreciendo la aparición de oxímetros de pulso más pequeños y más económicos, difundiendo su utilización ampliamente. METODOLOGÍA: Se realizó una búsqueda en las bases de datos bibliográficas detalladas a continuación, en el repositorio y página de OMS y OPS, en BRISA de RedETSA, en sitios de Agencias de Evaluación de Tecnologías Sanitarias y Agencias nacionales e internacionales reguladoras de alimentos, medicamentos y dispositivos, las que se detallan más abajo, en Tripdatabase, Epistemonikos, buscadores genéricos de Internet como google académico. Se buscaron Guía de Práctica Clínica de las sociedades relacionadas con atención del recién nacido, neonatología, cuidados críticos, terapias respiratorias invasivas, priorizando las del Ministerio de Salud de la Nación Argentina y de la Provincia de Neuquén. RESULTADOS: Se realizó una búsqueda en los registros de la Administración Nacional de Medicamentos, Alimentos y Tecnología Médica (ANMAT), de las opciones de oximetría de pulso disponibles para comercialización en Argentina. Descripción de la Tecnología: Se identifican dos tecnologías disponibles en Argentina que se corresponden con nuestra definición de nueva generación de oxímetro de pulso. Tecnologías alternativas: Medición de PO2 capilar por saturometría convencional y punción para medición de gases arteriales. CONCLUSIONES: La utilización de la oximetría de pulso está recomendada a nivel mundial para uso en pacientes críticos de neonatología y rastreo de cardiopatías congénitas en recién nacidos sanos . Al hablar de las nuevas generaciones de oximetría de pulso (tecnología SET y nuevos algoritmos) no existe evidencia de alta calidad que respalde el reemplazo de los convencionales, teniendo en cuenta su elevado costo, costo de oportunidad y potencial impacto en la equidad. Los expertos consultados muestran satisfacción con los resultados obtenidos con este tipo de nueva tecnología, pero no puede respaldarse su percepción en evidencias científicas sólidas con bajo riesgo de sesgos Al considerar que la tecnología SET está en uso desde hace 10 años en la neonatología del HPN mediante donaciones de programas verticales, se recomienda la gestión de estas adquisiciones en forma centralizada y de esta manera unificar los criterios para los Servicios de Neonatología de la provincia. Se recomienda centralizar y revisar los criterios de aceptación de donaciones de equipos médicos. Se recomienda la renovación de equipamientos según necesidad en el Servicio de Neonatología del HPN, siendo esta donde se internan los pacientes críticos y la redistribución de los equipos antiguos en el resto de los hospitales de la provincia. En todos los casos es necesario un plan de gestión del ciclo de la tecnología que incluya los correspondientes mantenimientos preventivos y correctivos, el monitoreo de fallas y la planificación a mediano y largo plazo.


Assuntos
Oximetria/instrumentação , Oximetria/normas , Neonatologia/organização & administração , Avaliação da Tecnologia Biomédica , Avaliação em Saúde , Análise Custo-Benefício
9.
Anesth Analg ; 131(3): e138-e141, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-31985496

RESUMO

Regional cerebral oxygenation index (rSO2) based on near-infrared spectroscopy (NIRS) is frequently used to detect low venous oxyhemoglobin saturation (ScvO2). We compared the performance of 2 generations of NIRS devices. Clinically obtained, time-matched cerebral rSO2 and ScvO2 values were compared in infants monitored with the FORE-SIGHT (n = 73) or FORE-SIGHT ELITE (n = 47) by linear regression and Bland-Altman analyses. In both devices, cerebral rSO2 correlated poorly with measured ScvO2 (FORE-SIGHT partial correlation 0.50 [95% confidence interval {CI}, 0.40-0.58]; FORE-SIGHT ELITE partial correlation 0.47 [0.39-0.55]) and mean bias was +8 (standard deviation [SD] 13.2) for FORE-SIGHT and +14 (SD 12.5) for FORE-SIGHT ELITE. When ScvO2 was <30%, rSO2 was <40 in 8% of FORE-SIGHT ELITE readings. Future NIRS should be validated in more hypoxic cohorts.


Assuntos
Encéfalo/irrigação sanguínea , Procedimentos Cirúrgicos Cardíacos , Cardiopatias Congênitas/cirurgia , Hipóxia Encefálica/diagnóstico , Oximetria/instrumentação , Oxiemoglobinas/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Biomarcadores/sangue , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Desenho de Equipamento , Humanos , Hipóxia Encefálica/sangue , Hipóxia Encefálica/etiologia , Recém-Nascido , Valor Preditivo dos Testes , Reprodutibilidade dos Testes
10.
Adv Exp Med Biol ; 1232: 3-9, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893387

RESUMO

Neonates with hypoxic-ischaemic (HI) brain injury were monitored using a broadband near-infrared spectroscopy (NIRS) system in the neonatal intensive care unit. The aim of this work is to use the NIRS cerebral oxygenation data (HbD = oxygenated-haemoglobin - deoxygenated-haemoglobin) combined with arterial saturation (SaO2) from pulse oximetry to calculate cerebral blood flow (CBF) based on the oxygen swing method, during spontaneous desaturation episodes. The method is based on Fick's principle and uses HbD as a tracer; when a sudden change in SaO2 occurs, the change in HbD represents a change in tracer concentration, and thus it is possible to estimate CBF. CBF was successfully calculated with broadband NIRS in 11 HIE infants (3 with severe injury) for 70 oxygenation events on the day of birth. The average CBF was 18.0 ± 12.7 ml 100 g-1 min-1 with a range of 4 ml 100 g-1 min-1 to 60 ml 100 g-1 min-1. For infants with severe HIE (as determined by magnetic resonance spectroscopy) CBF was significantly lower (p = 0.038, d = 1.35) than those with moderate HIE on the day of birth.


Assuntos
Lesões Encefálicas , Encéfalo , Circulação Cerebrovascular , Oximetria , Oxigênio , Espectroscopia de Luz Próxima ao Infravermelho , Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Lesões Encefálicas/diagnóstico por imagem , Humanos , Recém-Nascido , Oximetria/instrumentação , Oximetria/métodos , Oxigênio/metabolismo
11.
Adv Exp Med Biol ; 1232: 19-24, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893389

RESUMO

The Consensus on Resuscitation Science and Treatment Recommendations indicate the target SpO2 values during the first 10 min of life. There are a few studies of values of brain regional saturation of oxygen (rSO2) in newborns, conventional instruments are large and not suitable for measuring in the delivery room. The purpose of this study was to develop reference values for brain rSO2 up to 10 min after birth and to review the changes in cerebral oxygenation in late preterm and term newborn infants immediately after birth. METHOD: We evaluated both brain rSO2 and SpO2 at 1, 3, 5 and 10 min after birth in 100 neonates. rSO2, was measured at the forehead using a finger-mounted oximeter. This is 1/100 the size of conventional NIRS and can be carried. To measure SpO2, a Radical-7 was used. This study was approved by the institutional review board at our hospital. RESULTS: The gestational age and birth weight were 37.9 ± 1.2 weeks and 2825 ± 429 g, respectively. Eighty-seven infants and 13 infants were term and late preterm infants, respectively, and there were 21 vaginal deliveries and 79 cesarean sections. In all cases, rSO2 levels were measured at 1, 3, 5, and 10 min after birth. For the SpO2 measurements, nine cases at 1 min, 40 cases at 3 min, 81 cases at 5 min and 93 cases at 10 min were available. The median rSO2 level was 43% at 1 min after birth, 48% at 3 min, 52% at 5 min and 57% at 10 min. CONCLUSION: We used a finger-mounted oximeter to observe changes in brain rSO2 values of 100 normal transition infants. It was easier to detect rSO2 in comparison to the peripheral oxygen saturation monitored by our pulse oximeter. Brain rSO2 values might be useful to evaluate oxygenation immediately after birth.


Assuntos
Encéfalo , Oximetria , Encéfalo/fisiologia , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Oximetria/instrumentação , Oximetria/métodos , Oxigênio/análise , Valores de Referência
12.
Adv Exp Med Biol ; 1232: 177-182, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893408

RESUMO

Tumor hypoxia may play a fundamental role in determining the radiotherapy outcome for several cancer types. Functional imaging with hypoxia specific radiotracers offers a way to visualize and quantify regions of increased radioresistance, which may benefit from dose escalation strategies. Conversion of the uptake in positron emission tomography (PET) images into oxygenation maps offers a way to quantitatively characterize the microenvironment. However, normalization of the uptake with respect to a well-oxygenated reference volume (WOV), which should be properly selected, is necessary when using conversion functions. This study aims at assessing the sensitivity of quantifying tumor oxygenation based on 18F-fluoromisonidazole (FMISO) PET with respect to the choice of the location and the oxygenation level of the WOV in head and neck cancer patients. WOVs varying not only in shape and location but also with respect to the assigned pO2 level were considered. pO2 values other than the standard 60 mmHg were selected according to the specific tissue type included in the volume. For comparison, the volume which would be considered as hypoxic based on a tissue-to-muscle ratio equal to 1.4 was also delineated, as conventionally done in clinical practice. Hypoxia mapping strategies are found highly sensitive to selection of the location of well-oxygenated region, but also on its assigned oxygenation level, which is crucial for hypoxia-guided adaptive dose escalation strategies.


Assuntos
Neoplasias de Cabeça e Pescoço , Oximetria/instrumentação , Oximetria/normas , Oxigênio , Tomografia por Emissão de Pósitrons , Hipóxia Tumoral , Neoplasias de Cabeça e Pescoço/fisiopatologia , Humanos , Misonidazol/análogos & derivados , Misonidazol/metabolismo , Oxigênio/metabolismo , Microambiente Tumoral
13.
Adv Exp Med Biol ; 1232: 253-259, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893418

RESUMO

BACKGROUND: Near-infrared spectroscopy (NIRS) tissue oximeters enable non-invasive measurement of muscle oxygenation and perfusion. Several NIRS oximeters are currently available, particularly for muscle measurements. AIM: To evaluate the agreement of oxygenation and perfusion measurements obtained by two devices (Moxy, Fortiori Designs LLC, USA, and Nimo, Nirox, Italy) during an arterial occlusion test on the arm. SUBJECT AND METHODS: Arterial occlusions were conducted at the arm of one individual for 10 min with 200 mmHg. Measurements were made twice a day on five different days. Both NIRS devices were fixed at the arm (covering the muscles extensor carpi ulnaris, extensor digitorum, and flexor carpi ulnaris). RESULTS: The experiment revealed that i) both devices could detect changes in muscle oxygenation and perfusion during the occlusion, but ii) the magnitudes and dynamic changes differed between the two devices. DISCUSSION AND CONCLUSION: Both devices had different performances with regard to the measurement of tissue oxygenation and perfusion. This study shows that it might be worthwhile to compare all NIRS tissue oximeters currently available for muscle measurement in a large systematic study to increase the comparability of measurements obtained with different devices.


Assuntos
Oximetria , Oxigênio , Adulto , Humanos , Itália , Masculino , Músculo Esquelético/metabolismo , Oximetria/instrumentação , Oximetria/normas , Oxigênio/metabolismo , Consumo de Oxigênio , Espectroscopia de Luz Próxima ao Infravermelho
14.
Adv Exp Med Biol ; 1232: 323-329, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893427

RESUMO

Recent guidelines on cardiopulmonary resuscitation (CPR) have stressed the necessity to improve the quality of CPR. Our previous studies demonstrated the usefulness of monitoring cerebral blood oxygenation (CBO) during CPR by near-infrared spectroscopy (NIRS). The present study evaluates whether the NIRO-CCR1, a new NIRS device, is as useful in the clinical setting as the NIRO-200NX. We monitored CBO in 20 patients with cardiac arrest by NIRS. On the arrival of patients at the emergency department, the attending physician immediately assessed whether the patient was eligible for this study after conventional advanced life support and, if eligible, measured CBO in the frontal lobe by NIRS. We found that in all patients, the cerebral blood flow waveform was in synchrony with the chest compressions. Moreover, the tissue oxygenation index increased following cardiopulmonary bypass (CPB) in patients undergoing CPB, including one patient in whom CBO was monitored using the NIRO-CCR1. In addition, although the NIRO-CCR1 could display the pulse rate (Tempo) in real time, Tempo was not always detected, despite detection of the cerebral blood flow waveform. This suggested that chest compressions may not have been effective, indicating that the NIRO-CCR1 also seems useful to assess the quality of CPR. This study suggests that the NIRO-CCR1 can measure CBO during CPR in patients with cardiac arrest as effectively as the NIRO-200NX; in addition, the new NIRO-CCR1 may be even more useful, especially in prehospital fields (e.g. in an ambulance), since it is easy to carry.


Assuntos
Reanimação Cardiopulmonar , Circulação Cerebrovascular , Parada Cardíaca , Monitorização Fisiológica , Oximetria , Espectroscopia de Luz Próxima ao Infravermelho , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica/instrumentação , Monitorização Fisiológica/normas , Oximetria/instrumentação , Oximetria/normas , Projetos Piloto , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Espectroscopia de Luz Próxima ao Infravermelho/normas
15.
Adv Exp Med Biol ; 1232: 339-345, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893429

RESUMO

We used a miniature broadband NIRS system to monitor concentration changes in brain oxygenation (oxy- and deoxy- haemoglobin [HbO2], [HHb]) and oxidised cytochrome-c-oxidase ([oxCCO]) during a high +Gz acceleration, induced by a human centrifuge, on two healthy experienced volunteers (2 male, 34 and 37 years). We performed a sequence of several +Gz exposures that were terminated at the onset of visual symptoms (loss of peripheral vision). Systemic parameters were recorded (i.e. heart rate, blood pressure and arterial saturation), and brain tissue blood volume changes ([HbT] = [HbO2] + [HHb]) and oxygen delivery ([HbDiff] = [HbO2] - [HHb]) were calculated. Volunteer 1 demonstrated a decrease in [HbT] of -3.49 ± 0.02 µMol and [HbDiff] of -3.23 ± 0.44 µMol, and an increase of [oxCCO] of 0.42 ± 0.01µMol. Volunteer 2 demonstrated a decrease in [HbDiff] of -4.37 ± 0.23 µMol, and no significant change in [HbT] (0.53 ± 0.06 µMol) and [oxCCO] (0.09 ± 0.06 µMol). The variability of the brain metabolic response was related to the level of ischaemia, suggesting that suppression of metabolism was due to lack of glucose substrate delivery rather than oxygen availability.


Assuntos
Aceleração , Complexo IV da Cadeia de Transporte de Elétrons , Hemodinâmica , Espectroscopia de Luz Próxima ao Infravermelho , Adulto , Encéfalo/enzimologia , Encéfalo/metabolismo , Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Voluntários Saudáveis , Humanos , Masculino , Estresse Oxidativo , Oximetria/instrumentação , Oxigênio/metabolismo
16.
Adv Exp Med Biol ; 1232: 347-354, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893430

RESUMO

In preterm infants, there is a risk of long-term cognitive, motor and behavioral impairments due to hemorrhagic and/or ischemic lesions. If detected early, lesions can be prevented. A bedside imaging modality, capable of early detection of both disorders, is necessary. We present the state of development of a tomographic imager (named Pioneer), that will be capable of determining the oxygenation of the preterm-infant brain with high spatial resolution. Pioneer is a time-resolved near-infrared optical tomography (TR NIROT) instrument. It employs multiple wavelength laser light in short pulses on 11 distinct locations and measures the re-emerging light in a contactless fashion by means of a time-correlated single-photon counting (TCSPC) camera (named Piccolo) covering ~4.9 cm2 with 300 detectors. Timing response of the entire system is 116 ps. An in-house designed biocompatible source ring ensures fixed relative positions of sources and detectors and provides a secure interface between the patient and the probe. At the present state, the NIROT Pioneer system successfully detected a 6x6x50 mm3 inclusion 3 cm deep inside a phantom. These results confirm that the Pioneer imager is working as expected and is on a solid path towards full 3D tissue oxygenation imaging.


Assuntos
Encéfalo , Recém-Nascido Prematuro , Oximetria , Oxigênio , Encéfalo/diagnóstico por imagem , Humanos , Recém-Nascido , Oximetria/instrumentação , Oximetria/métodos , Oximetria/normas , Oxigênio/metabolismo , Imagens de Fantasmas
17.
Med Biol Eng Comput ; 58(2): 239-247, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31741291

RESUMO

This study investigated the accuracy, drift, and clinical usefulness of a new optical transcutaneous oxygen tension (tcPO2) measuring technique, combined with a conventional electrochemical transcutaneous carbon dioxide (tcPCO2) measurement and reflectance pulse oximetry in the novel transcutaneous OxiVenT™ Sensor. In vitro gas studies were performed to measure accuracy and drift of tcPO2 and tcPCO2. Clinical usefulness for tcPO2 and tcPCO2 monitoring was assessed in neonates. In healthy adult volunteers, measured oxygen saturation values (SpO2) were compared with arterially sampled oxygen saturation values (SaO2) during controlled hypoxemia. In vitro correlation and agreement with gas mixtures of tcPO2 (r = 0.999, bias 3.0 mm Hg, limits of agreement - 6.6 to 4.9 mm Hg) and tcPCO2 (r = 0.999, bias 0.8 mm Hg, limits of agreement - 0.7 to 2.2 mm Hg) were excellent. In vitro drift was negligible for tcPO2 (0.30 (0.63 SD) mm Hg/24 h) and highly acceptable for tcPCO2 (- 2.53 (1.04 SD) mm Hg/12 h). Clinical use in neonates showed good usability and feasibility. SpO2-SaO2 correlation (r = 0.979) and agreement (bias 0.13%, limits of agreement - 3.95 to 4.21%) in healthy adult volunteers were excellent. The investigated combined tcPO2, tcPCO2, and SpO2 sensor with a new oxygen fluorescence quenching technique is clinically usable and provides good overall accuracy and negligible tcPO2 drift. Accurate and low-drift tcPO2 monitoring offers improved measurement validity for long-term monitoring of blood and tissue oxygenation. Graphical abstract.


Assuntos
Dióxido de Carbono/sangue , Oximetria/instrumentação , Oxigênio/sangue , Pele/irrigação sanguínea , Adulto , Desenho de Equipamento , Feminino , Humanos , Recém-Nascido , Masculino , Oximetria/métodos , Adulto Jovem
18.
Anesthesiology ; 132(3): 424-439, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31743149

RESUMO

BACKGROUND: Vital signs are usually recorded once every 8 h in patients at the hospital ward. Early signs of deterioration may therefore be missed. Wireless sensors have been developed that may capture patient deterioration earlier. The objective of this study was to determine whether two wearable patch sensors (SensiumVitals [Sensium Healthcare Ltd., United Kingdom] and HealthPatch [VitalConnect, USA]), a bed-based system (EarlySense [EarlySense Ltd., Israel]), and a patient-worn monitor (Masimo Radius-7 [Masimo Corporation, USA]) can reliably measure heart rate (HR) and respiratory rate (RR) continuously in patients recovering from major surgery. METHODS: In an observational method comparison study, HR and RR of high-risk surgical patients admitted to a step-down unit were simultaneously recorded with the devices under test and compared with an intensive care unit-grade monitoring system (XPREZZON [Spacelabs Healthcare, USA]) until transition to the ward. Outcome measures were 95% limits of agreement and bias. Clarke Error Grid analysis was performed to assess the ability to assist with correct treatment decisions. In addition, data loss and duration of data gaps were analyzed. RESULTS: Twenty-five high-risk surgical patients were included. More than 700 h of data were available for analysis. For HR, bias and limits of agreement were 1.0 (-6.3, 8.4), 1.3 (-0.5, 3.3), -1.4 (-5.1, 2.3), and -0.4 (-4.0, 3.1) for SensiumVitals, HealthPatch, EarlySense, and Masimo, respectively. For RR, these values were -0.8 (-7.4, 5.6), 0.4 (-3.9, 4.7), and 0.2 (-4.7, 4.4) respectively. HealthPatch overestimated RR, with a bias of 4.4 (limits: -4.4 to 13.3) breaths/minute. Data loss from wireless transmission varied from 13% (83 of 633 h) to 34% (122 of 360 h) for RR and 6% (47 of 727 h) to 27% (182 of 664 h) for HR. CONCLUSIONS: All sensors were highly accurate for HR. For RR, the EarlySense, SensiumVitals sensor, and Masimo Radius-7 were reasonably accurate for RR. The accuracy for RR of the HealthPatch sensor was outside acceptable limits. Trend monitoring with wearable sensors could be valuable to timely detect patient deterioration.


Assuntos
Monitorização Intraoperatória/instrumentação , Sinais Vitais , Dispositivos Eletrônicos Vestíveis , Idoso , Cuidados Críticos , Feminino , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Intraoperatória/métodos , Monitorização Fisiológica , Oximetria/instrumentação , Oximetria/métodos , Reprodutibilidade dos Testes , Taxa Respiratória , Resultado do Tratamento , Tecnologia sem Fio
19.
Blood Press Monit ; 25(1): 13-17, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31633521

RESUMO

BACKGROUND: Noninvasive blood-pressure measurement device and pulse oximeter are important for patient monitoring. When these are placed on the same side, cuff inflation sometimes causes measurement failure by pulse oximeter. OBJECTIVE: The present study aimed to compare the pulse oximeter alarm frequency and pulse-wave disappearance duration between noninvasive blood-pressure measurement using the deflation method and that using the linear inflation method. METHODS: The study included 10 healthy subjects. The cuff for automatic sphygmomanometer was wrapped on one side of the upper arm and for pulse oximeter was attached to the thumb of the same side of upper limbs. RESULTS: The alarm frequency was 0 and 26% using the linear inflation and the deflation methods, respectively. Additionally, the pulse-wave disappearance duration was significantly longer using the deflation method than that using the linear inflation method (10.0 ± 1.5 vs 1.7 ± 0.8 s). With the linear inflation method, this duration was or less 3 s. In the deflation method, an excess pressure of 40 mmHg was used, which caused the alarm to turn on. Additionally, the heart rate was found to influence the alarm occurrence during measurement using the deflation method. CONCLUSION: Heart rate may influence alarm occurrence during blood-pressure measurement using the step deflation method. Using the linear inflation method, the risks of alarm occurrence and measurement failure are low, even when the pulse oximeter and blood-pressure measurement cuffs are installed on the same side, suggesting that this method is suitable for clinical use.


Assuntos
Determinação da Pressão Arterial/métodos , Pressão Sanguínea , Oximetria/instrumentação , Esfigmomanômetros , Adulto , Pressão Sanguínea/fisiologia , Determinação da Pressão Arterial/instrumentação , Feminino , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...