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1.
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
2.
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
3.
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
4.
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
5.
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
6.
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
7.
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
8.
Zhongguo Yi Liao Qi Xie Za Zhi ; 43(5): 345-347, 2019 Sep 30.
Artigo em Chinês | MEDLINE | ID: mdl-31625332

RESUMO

This article describes the design of a portable blood oxygen simulation system that can be used to simulate various blood gas saturation states of the human body. The system can be used to simulate various states of blood gas saturation, and can also simulate large blood oxygen saturation dynamic range, pulse rate range and perfusion index range. It can be used for testing, but not for clinical examination instruments. Moreover, the system has the characteristics of small size and low cost compared with the commercial blood oxygen simulator. Although the simulation system is not directly used for the detection of blood gas saturation of patients, it is also an essential equipment in the production and testing process, so it has certain practical value.


Assuntos
Oximetria , Oxigênio , Frequência Cardíaca , Humanos , Oximetria/instrumentação , Oxigênio/análise
10.
Cell Biochem Biophys ; 77(3): 197-202, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31444784

RESUMO

Oxygen-sensing implants, composed of paramagnetic microcrystals embedded in a biocompatible polymer, are increasingly being used for electron paramagnetic resonance (EPR) oximetry in animal models and human subjects. The implants are stable and designed to stay in the tissues for indefinite periods. However, it is not known whether the crystals that may be exposed on the surface of the implants or leached out from the implants will induce cytotoxicity thereby compromising their biocompatibility over the long term. The goal of the current study was to evaluate the cytotoxicity of the implants and crystalline particulates under in vitro conditions. Apoptosis and cell viability studies were performed using L6, a rat muscle cell line and AsPC-1, a cancer cell line derived from human pancreatic adenocarcinoma. The results indicated that neither the intact implants nor their components elicit cytotoxicity, thus establishing their biocompatibility for use in human subjects.


Assuntos
Materiais Biocompatíveis/química , Oximetria/métodos , Oxigênio/análise , Animais , Apoptose/efeitos dos fármacos , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Espectroscopia de Ressonância de Spin Eletrônica , Humanos , Oximetria/instrumentação , Polímeros/química , Porfirinas/química , Próteses e Implantes , Ratos
11.
Vet Anaesth Analg ; 46(5): 636-642, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31377121

RESUMO

OBJECTIVE: Hemoglobin oxygen saturation (SO2) is measured by co-oximetry (SO2cox) or calculated from partial pressure of oxygen (PO2) using algorithms (SO2alg). To compare venous and systemic arterial blood sample data retrospectively and to examine whether temperature correction of PO2 is important. STUDY DESIGN: Retrospective study. ANIMALS: A group of 21 healthy, adult, sedated or anesthetized horses. METHODS: Mixed-venous and systemic arterial blood samples (1 mL) were anaerobically collected using commercial preheparinized syringes from the right ventricle and facial artery, respectively. Blood was analyzed using a commercial gas analyzer and human-specific co-oximeter within 10 minutes of collection or stored on ice and analyzed within 30 minutes. PO2 was measured at 37 °C and corrected using body temperature (Tcore) from a pulmonary artery catheter thermistor. SO2cox and hemoglobin subtypes were measured by co-oximetry (37 °C). An algorithm developed for Thoroughbred horse blood was used to calculate SO2alg using PO2 at 37 °C and SO2algcorr with PO2 corrected to Tcore. SO2alg and SO2algcorr were each paired with SO2cox using Bland-Altman (repeated measures) ratio of SO2alg/SO2cox (204 samples). RESULTS: SO2alg overestimated SO2cox when PO2 was <80 mmHg (10.7 kPa); ratio and limits of agreement: 1.2 (0.9-1.6) but became accurate when PO2 was ≥80 mmHg: 1.0 (1.0-1.0). With all data, SO2algcorr did not differ from SO2alg:1.1 (0.8-1.4). Methemoglobin (FMetHb) and carboxyhemoglobin (FCOHb) were significantly higher in venous [FMetHb: median (range): 1.8 (0-2.9)%; FCOHb: 0.1 (0-2)%] than in arterial blood [FMetHb: 0.5 (0-2.2)%; FCOHb: 0 (0-0.3)%]. CONCLUSIONS: The algorithm appeared robust when PO2 was ≥80 mmHg (10.7 kPa) but overestimated when PO2 was lower. Temperature correction was not important within 34.9-37.3 °C. CLINICAL RELEVANCE: SO2alg overestimation in venous blood can result in calculation of higher intrapulmonary shunt fraction than SO2cox values.


Assuntos
Algoritmos , Hemoglobinas/metabolismo , Cavalos/sangue , Oximetria/veterinária , Oxigênio/sangue , Animais , Humanos , Oximetria/instrumentação , Valor Preditivo dos Testes , Troca Gasosa Pulmonar , Fenômenos Fisiológicos Respiratórios , Estudos Retrospectivos , Temperatura Ambiente
13.
Undersea Hyperb Med ; 46(1): 1-6, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31154680

RESUMO

Hypoxia is one of the main problems an underwater diver may have to face. The probability of experiencing hypoxia is related to the type of dive and the equipment used. Hypoxia in diving is a potentially fatal event for the diver, as it can lead to the loss of brain functions and consequently to the loss of breathing control, all in the absence of specific premonitory symptoms. It is a risk that may be encountered more frequently by divers who use a closed-circuit rebreather (CCR). For those who use this type of equipment, hypoxia is usually the most frequent cause of death [1]. Our study was aimed at the detection of peripheral oxygen saturation in order to identify, in the future, a preclinical hypoxic condition. We combined the use of pulse oximetry with two forehead sensors on an underwater diver subject who was using an electronic closed-circuit rebreather (ECCR). Despite the known limits of this method and the preliminary status of these findings [2], the recorded data show a clear validity in the use of pulse oximetry in immersion for the detection of peripheral oxygen saturation. In the future, the pulse oximeter could become part of the instrumentation of the diver who uses CCR gear. The device could easily be implemented in these rebreathers. The possibility of being able to perform a basic instrumental analysis means that the diver can become more quickly aware of imminent hypoxia, characterized by the absence of clearly identifiable warning symptoms, and can put in place all the correct procedures for an emergency ascent, avoiding serious consequences.


Assuntos
Mergulho/efeitos adversos , Desenho de Equipamento , Hipóxia/diagnóstico , Oximetria , Oxigênio/sangue , Adulto , Gasometria/instrumentação , Gasometria/métodos , Equipamentos para Diagnóstico , Humanos , Hipóxia/sangue , Hipóxia/etiologia , Imersão , Masculino , Oximetria/instrumentação , Oximetria/métodos , Sintomas Prodrômicos , Água do Mar , Avaliação de Sintomas/instrumentação , Temperatura Ambiente
14.
JMIR Mhealth Uhealth ; 7(6): e12866, 2019 06 06.
Artigo em Inglês | MEDLINE | ID: mdl-31199331

RESUMO

BACKGROUND: Chronic obstructive pulmonary disease (COPD) patients can suffer from low blood oxygen concentrations. Peripheral blood oxygen saturation (SpO2), as assessed by pulse oximetry, is commonly measured during the day using a spot check, or continuously during one or two nights to estimate nocturnal desaturation. Sampling at this frequency may overlook natural fluctuations in SpO2. OBJECTIVE: This study used wearable finger pulse oximeters to continuously measure SpO2 during daily home routines of COPD patients and assess natural SpO2 fluctuations. METHODS: A total of 20 COPD patients wore a WristOx2 pulse oximeter for 1 week to collect continuous SpO2 measurements. A SenseWear Armband simultaneously collected actigraphy measurements to provide contextual information. SpO2 time series were preprocessed and data quality was assessed afterward. Mean SpO2, SpO2 SD, and cumulative time spent with SpO2 below 90% (CT90) were calculated for every (1) day, (2) day in rest, and (3) night to assess SpO2 fluctuations. RESULTS: A high percentage of valid SpO2 data (daytime: 93.27%; nocturnal: 99.31%) could be obtained during a 7-day monitoring period, except during moderate-to-vigorous physical activity (MVPA) (67.86%). Mean nocturnal SpO2 (89.9%, SD 3.4) was lower than mean daytime SpO2 in rest (92.1%, SD 2.9; P<.001). On average, SpO2 in rest ranged over 10.8% (SD 4.4) within one day. Highly varying CT90 values between different nights led to 50% (10/20) of the included patients changing categories between desaturator and nondesaturator over the course of 1 week. CONCLUSIONS: Continuous SpO2 measurements with wearable finger pulse oximeters identified significant SpO2 fluctuations between and within multiple days and nights of patients with COPD. Continuous SpO2 measurements during daily home routines of patients with COPD generally had high amounts of valid data, except for motion artifacts during MVPA. The identified fluctuations can have implications for telemonitoring applications that are based on daily SpO2 spot checks. CT90 values can vary greatly from night to night in patients with a nocturnal mean SpO2 around 90%, indicating that these patients cannot be consistently categorized as desaturators or nondesaturators. We recommend using wearable sensors for continuous SpO2 measurements over longer time periods to determine the clinical relevance of the identified SpO2 fluctuations.


Assuntos
Oximetria/instrumentação , Doença Pulmonar Obstrutiva Crônica/complicações , Dispositivos Eletrônicos Vestíveis/normas , Atividades Cotidianas , Gasometria , Humanos , Países Baixos , Oximetria/métodos , Oximetria/normas , Oxigênio/análise , Doença Pulmonar Obstrutiva Crônica/psicologia , Dispositivos Eletrônicos Vestíveis/estatística & dados numéricos
15.
Medicina (Kaunas) ; 55(5)2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-31117234

RESUMO

Background and Objectives: Postoperative cognitive disturbances (POCD) can significantly alter postoperative recovery. Inadequate intraoperative cerebral oxygen supply is one of the inciting causes of POCD. Near-infrared spectroscopy (NIRS) devices monitor cerebral oxygen saturation continuously and can help to guide intraoperative patient management. The aim of the study was to evaluate the applicability of the NIRS-based clinical algorithm during spinal neurosurgery and to find out whether it can influence postoperative cognitive performance. Materials and Methods: Thirty four patients scheduled for spinal neurosurgery were randomized into a study group (n = 23) and a control group (n = 11). We monitored regional cerebral oxygen saturation (rScO2) throughout surgery, using a NIRS device (INVOS 4100). If rScO2 dropped bilaterally or unilaterally by more than 20% from baseline values, or under an absolute value of 50%, the NIRS-based algorithm was initiated in the study group. In the control group, rScO2 was monitored blindly. To evaluate cognitive function, Montreal-Cognitive Assessment (MoCA) scale was used in both groups before and after the surgery. Results: In the study group, rScO2 dropped below the threshold in three patients and the NIRS-based algorithm was activated. Firstly, we verified correct positioning of the head; secondly, we increased mean systemic arterial pressure in the three patients by injecting repeated intravenous bolus doses of Ephedrine, ultimately resulting in an rScO2 increase above the approved threshold level. None of the three patients showed POCD. In the control group, one patient showed a drop in rScO2 of 34% from baseline and presented with a POCD. RScO2 drop occurred with other stable intraoperative measurements. Conclusions: A significant rScO2 drop may occur during spinal surgery in prone position despite other intraoperative measurements remaining stable, allowing it to stay otherwise unrecognized. Use of the NIRS-based clinical algorithm can help to avoid POCD in patients after spinal surgery.


Assuntos
Algoritmos , Cognição , Complicações Pós-Operatórias/diagnóstico , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Coluna Vertebral/cirurgia , Adulto , Idoso , Cérebro/irrigação sanguínea , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neurocirurgia/instrumentação , Neurocirurgia/métodos , Neurocirurgia/normas , Oximetria/instrumentação , Oximetria/métodos , Complicações Pós-Operatórias/fisiopatologia , Estudos Prospectivos , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Espectroscopia de Luz Próxima ao Infravermelho/tendências
16.
Sensors (Basel) ; 19(7)2019 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-30986953

RESUMO

Wearable monitoring devices are now a usual commodity in the market, especially for the monitoring of sports and physical activity. However, specialized wearable devices remain an open field for high-risk professionals, such as military personnel, fire and rescue, law enforcement, etc. In this work, a prototype wearable instrument, based on reconfigurable technologies and capable of monitoring electrocardiogram, oxygen saturation, and motion, is presented. This reconfigurable device allows a wide range of applications in conjunction with mobile devices. As a proof-of-concept, the reconfigurable instrument was been integrated into ad hoc glasses, in order to illustrate the non-invasive monitoring of the user. The performance of the presented prototype was validated against a commercial pulse oximeter, while several alternatives for QRS-complex detection were tested. For this type of scenario, clustering-based classification was found to be a very robust option.


Assuntos
Eletrocardiografia Ambulatorial/instrumentação , Eletrocardiografia/instrumentação , Monitorização Fisiológica , Dispositivos Eletrônicos Vestíveis , Humanos , Oximetria/instrumentação , Processamento de Sinais Assistido por Computador
17.
S Afr Med J ; 109(3): 154-158, 2019 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-30834870

RESUMO

BACKGROUND: Low-cost, portable fingertip pulse oximeters are widely available to health professionals and the public. They are often not tested to International Organization for Standardization standards, or only undergo accuracy studies in healthy volunteers under ideal laboratory conditions. OBJECTIVES: To pragmatically evaluate the agreement between one such device and a conventional bedside pulse oximeter in a clinical setting, in patients with varied comorbidities and skin pigmentations. METHODS: A single-centre equipment comparison study was conducted. Simultaneous measurements were obtained in 220 patients with both a Contec CMS50D Fingertip Pulse Oximeter and a Nihon Kohden Life Scope MU-631 RK conventional bedside monitor. Peripheral oxygen saturations (SpO2) and pulse rates were documented, and patients' skin tone was recorded using the Fitzpatrick scale. Data were assessed using a Bland-Altman analysis with bias, precision and limits of agreement (LOA) calculated with 95% confidence intervals (CIs). A priori acceptability for LOA was determined to be 3%, in keeping with international standards. RESULTS: The mean difference (therefore bias) between the conventional and fingertip oximeters for all data was -0.55% (95% CI -0.73 - -0.36). Upper and lower limits of agreement were 2.16% (95% CI 1.84 - 2.47) and -3.25% (95% CI -3.56 - -2.94). Regression analysis demonstrated worsening agreement with decreasing SpO2. When samples were separated into 'normal' (SpO2≥93%) and 'hypoxaemic' (SpO2 <93%) groups, the normal range displayed acceptable agreement between the two oximeters (bias -0.20% with LOA 2.20 - -2.27), while the hypoxaemic group fell outside the study's a priori limits. Heart rate measurements had a mean difference of -0.43 bpm (LOA -5.61 - 4.76). The study was not powered to detect differences among the skin tones, but demonstrated no trend for this parameter to alter the SpO2measurements. CONCLUSIONS: During normoxia, portable fingertip pulse oximeters are reliable indicators of SpO2and pulse rates in patients with various comorbidities in a pragmatic clinical context. However, they display worsening agreement with conventional pulse oximeters during hypoxaemia. Skin tones do not appear to affect measurements adversely.


Assuntos
Desenho de Equipamento , Oximetria/instrumentação , Assistência Perioperatória/instrumentação , Sistemas Automatizados de Assistência Junto ao Leito , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Dedos , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto Jovem
18.
Physiotherapy ; 105(3): 297-306, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-30876715

RESUMO

BACKGROUND AND AIM: Telehealth is a strategy to expand the reach of pulmonary rehabilitation (PR). Smartphones can monitor and transmit oxygen saturation (SpO2) and heart rate (HR) data to ensure patient safety during home-based or other exercise. The purpose of this study was to evaluate the usability, validity and reliability of a Kenek O2 pulse oximeter and custom prototype smartphone application (smartphone oximeter) during rest and exercise in healthy participants and those with chronic lung disease. METHODS: Fifteen individuals with chronic lung disease and 15 healthy controls were recruited. SpO2 and HR were evaluated at rest and during cycling and walking. SpO2 was valid if the mean bias was within +±2%, the level of agreement (LoA) was within ±4%; HR was valid if the mean bias was within ±5 beats per min (bpm), LoA was within ±10bpm. Usability was assessed with a questionnaire and direct observation. RESULTS: The smartphone oximeter was deemed easy to use. At rest, SpO2 measures were valid in both groups (bias <2%, lower bound LoA -2 to 3%). During exercise, SpO2 measurement did not meet validity and reliability thresholds in the patients with chronic lung disease, but was accurate for the healthy controls. HR recording during exercise or rest was not valid (LoA>10bpm) in either group. CONCLUSIONS: The smartphone oximeter did not record HR or SpO2 accurately in patients with chronic lung disease during exercise, although SpO2 was valid at rest. During exercise, patients with chronic lung disease should pause to ensure greatest accuracy of SpO2 and HR measurement.


Assuntos
Exercício , Pneumopatias/fisiopatologia , Aplicativos Móveis , Oximetria/instrumentação , Smartphone , Telemedicina , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Dedos/irrigação sanguínea , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Reprodutibilidade dos Testes
19.
A A Pract ; 12(11): 441-443, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30663993

RESUMO

Cerebral oximetry is commonly being advocated as a monitor for regional cerebral tissue oxygenation during cardiac surgery. We have increasing concern about the accuracy of this monitor, including the current systems entering the market, with new probes and algorithms. We present 2 cases where cerebral oximetry failed to accurately portray cerebral oxygenation. In the current form, cerebral oximetry may at best be an expensive tool without any benefit on outcomes. In addition, it may contribute to misleading and confusing clinical data.


Assuntos
Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Oximetria/instrumentação , Perfusão/métodos , Idoso de 80 Anos ou mais , Falha de Equipamento , Feminino , Humanos , Pessoa de Meia-Idade , Monitorização Fisiológica/instrumentação , Perfusão/instrumentação
20.
Biochim Biophys Acta Mol Basis Dis ; 1865(4): 749-758, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30593898

RESUMO

Impaired tissue oxygenation is the key pathomechanism in the development of organ dysfunction in shock; mitochondrial impairment can aggravate the condition. However, measuring tissue oxygenation directly and non-invasively still poses a clinical challenge. A novel device (COMET) allows the assessment of mitochondrial oxygen metabolism using the Protoporphyrin IX Triplet State Lifetime Technique (PpIX-TSLT). Critically ill patients, especially in sepsis, often exhibit oedema which may interfere with the COMET measurement. Furthermore, patients' physical activity level differs significantly before and during hospitalisation. Thus, the aim of this study was to identify the effects of physical activity and body composition on mitochondrial oxygen tension (mitoPO2) and consumption (mitoVO2) in healthy controls (N = 40). Furthermore, the study tested the repeatability of the COMET variables and identified covariates. Multiple COMET measurements were performed before (T1, T2), during and after (T3, T4) ergometry. Body composition was assessed by bioimpedance analysis. Physiological variables (blood pressure, heart rate, oxygen saturation) were recorded. In the analytical sample (n = 26), physical activity significantly decreased mitoVO2; other COMET variables remained unchanged between T2 and T3. During ergometry, mitoPO2 increased significantly. The distribution of body water significantly influenced mitoVO2. In our setting, the method demonstrated moderate repeatability. Variables of fitness (heart rate recovery, phase angle and physical activity level), signal quality and duration of exposure to 5-aminolevulinic acid (obligatory for PpIX-TSLT) were identified as significant covariates of mitoVO2. Mitochondrial oxygen delivery (mitoDO2) was established as a new variable of COMET analysis. Results of this pilot study should be validated in future studies.


Assuntos
Ergometria/métodos , Exercício , Mitocôndrias/metabolismo , Oximetria/métodos , Consumo de Oxigênio , Adulto , Composição Corporal , Ergometria/instrumentação , Feminino , Humanos , Masculino , Oximetria/instrumentação , Oxigênio/metabolismo
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