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1.
Adv Exp Med Biol ; 1232: 285-290, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893422

RESUMO

In neonatal intensive care units (NICUs), 87.5% of alarms by the monitoring system are false alarms, often caused by the movements of the neonates. Such false alarms are not only stressful for the neonates as well as for their parents and caregivers, but may also lead to longer response times in real critical situations. The aim of this project was to reduce the rates of false alarms by employing machine learning algorithms (MLA), which intelligently analyze data stemming from standard physiological monitoring in combination with cerebral oximetry data (in-house built, OxyPrem). MATERIALS & METHODS: Four popular MLAs were selected to categorize the alarms as false or real: (i) decision tree (DT), (ii) 5-nearest neighbors (5-NN), (iii) naïve Bayes (NB) and (iv) support vector machine (SVM). We acquired and processed monitoring data (median duration (SD): 54.6 (± 6.9) min) of 14 preterm infants (gestational age: 26 6/7 (± 2 5/7) weeks). A hybrid method of filter and wrapper feature selection generated the candidate subset for training these four MLAs. RESULTS: A high specificity of >99% was achieved by all four approaches. DT showed the highest sensitivity (87%). The cerebral oximetry data improved the classification accuracy. DISCUSSION & CONCLUSION: Despite a (as yet) low amount of data for training, the four MLAs achieved an excellent specificity and a promising sensitivity. Presently, the current sensitivity is insufficient since, in the NICU, it is crucial that no real alarms are missed. This will most likely be improved by including more subjects and data in the training of the MLAs, which makes pursuing this approach worthwhile.


Assuntos
Unidades de Terapia Intensiva Neonatal , Terapia Intensiva Neonatal , Aprendizado de Máquina , Monitorização Fisiológica , Oximetria , Teorema de Bayes , Circulação Cerebrovascular , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Terapia Intensiva Neonatal/métodos , Monitorização Fisiológica/métodos , Oximetria/métodos , Oximetria/normas
2.
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
3.
Adv Exp Med Biol ; 1232: 369-374, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893433

RESUMO

Multispectral/hyperspectral imaging is one of the imaging modalities to visualize and quantify blood supply in surface tissues such as skin or mucosa. The results of visualization can be potentially affected by various factors, for instance by elevated methemoglobin (MetHb) content (e.g., methemoglobinemia). The scope of the current study is to develop a robust approach for fabrication and validation of tissue-mimicking phantoms, which can be used to assess and improve tissue oximetry. METHODS: The realistic tissue mimicking gelatin-based phantoms with intralipid (4% v/v) and/or hemoglobins (oxy-, deoxyhemoglobins, and MetHb) were molded between two coverslips separated by 2-mm wires. The hemoglobin solutions were prepared by dissolving the lyophilized human hemoglobin powder (H7379, Sigma-Aldrich) in the deionized water. Sodium dithionite (85% purity, 157,953, Sigma-Aldrich) was used to reduce MetHb solution. The phantoms were imaged using a multispectral imaging device (Oxilight, Canada).To demonstrate the utility, the developed approach is applied to emulate elevated systemic MetHb content. RESULTS: Initial results show that elevated systemic MetHb (2.0-6.7% of total blood) does not impact the accuracy of tissue oximetry imaging. DISCUSSION: A robust method for fabrication and optical validation of biocompatible tissue-mimicking phantoms has been developed.The proposed phantom design allows combining different phantoms into multilayer (sandwich) structures, which can be used to emulate a wide range of topical and systemic conditions.


Assuntos
Gelatina , Oximetria , Imagens de Fantasmas , Canadá , Gelatina/química , Humanos , Metemoglobina/análise , Metemoglobinemia/diagnóstico , Oximetria/métodos , Oximetria/normas , Imagens de Fantasmas/normas
4.
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
5.
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
6.
Adv Exp Med Biol ; 1232: 145-153, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31893405

RESUMO

The aim of the paper is to discuss what currently is feasible clinically to measure the level of oxygen and how that measurement can be clinically useful. Because oxygen in tissues is quite heterogeneous and all methods of measurement can only provide an average across heterogeneities at some spatial and temporal resolution, the values that are obtained may have limitations on their clinical utility. However, even if such limitations are significant, if one utilizes repeated measurements and focuses on changes in the measured levels, rather than 'absolute levels', it may be possible to obtain very useful clinical information. While these considerations are especially pertinent in cancer, they also pertain to most other types of pathology.


Assuntos
Oximetria , Oxigênio , Espectroscopia de Ressonância de Spin Eletrônica , Humanos , Neoplasias/metabolismo , Oximetria/métodos , Oxigênio/análise , Oxigênio/metabolismo
8.
Molecules ; 24(18)2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31487945

RESUMO

Background: To evaluate the effectiveness/side-effects of osteopathic manipulation treatment (OMT) performed on the 7th post-natal day, on cerebro-splanchnic oximetry, tissue activation and hemodynamic redistribution in late preterm (LP) infants by using near infrared spectroscopy (NIRS). Methods: Observational pretest-test study consisting in a cohort of 18 LPs who received OMT on the 7th post-natal day. NIRS monitoring was performed at three different time-points: 30 min before (T0), (30 min during (T1) and 30 min after OMT (T2). We evaluated the effects of OMT on the following NIRS parameters: cerebral (c), splanchnic (s) regional oximetry (rSO2), cerebro-splanchnic fractional tissue oxygen extraction (FTOE) and hemodynamic redistribution (CSOR). Results: crSO2 and cFTOE significantly (P < 0.001) improved at T0-T2; srSO2 significantly (P < 0.001) decreased and sFTOE increased at T0-T1. Furthermore, srSO2 and sFTOE significantly improved at T1-T2. Finally, CSOR significantly (P < 0.05) increased at T0-T2. Conclusions: The present data show that OMT enhances cerebro-splanchnic oximetry, tissue activation and hemodynamic redistribution in the absence of any adverse clinical or laboratory pattern. The results indicate the usefulness of further randomized studies in wider populations comparing the effectiveness of OMT with standard rehabilitation programs.


Assuntos
Circulação Cerebrovascular , Manipulação Osteopática , Oximetria , Circulação Esplâncnica , Adulto , Gasometria , Feminino , Humanos , Recém-Nascido , Masculino , Manipulação Osteopática/métodos , Oximetria/métodos , Oxigênio/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho
9.
Pediatr Cardiol ; 40(7): 1523-1529, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31375852

RESUMO

Acute femoral artery occlusion is common in pediatric patients following cardiac catheterization. A variety of means are utilized to assess lower extremity (LE) perfusion and arterial patency following cardiac catheterization including palpation of pulses, pulse oximetry, subjective assessment of lower extremity color and temperature, and ultrasound. We sought to evaluate the utility of Near-Infrared Spectroscopy (NIRS) to monitor LE perfusion in pediatric patients undergoing cardiac catheterization. INVOS pediatric sensors were placed on bilateral LE in all pediatric patients ≤ 40 kg undergoing cardiac catheterization. Data were recorded continuously from the start of the procedure until 4-6 h after completion of the procedure. NIRS readings were compared between the accessed versus non-accessed LE at baseline before start of case, time of vascular access, arterial sheath exchange when applicable, sheath withdrawal, and Safeguard application, deflation, and removal. 133 patients underwent 152 catheterizations with mean age 2.4 ± 2.3 years and mean weight 12.4 ± 13.2 kg. NIRS oximetry readings were significantly decreased in the LE with arterial access compared to non-accessed LE from time of sheath insertion until removal of the pressure assist device post procedure. A greater difference was noted in smaller patients. NIRS oximetry readings did not correlate with subjective assessment of lower extremity perfusion after arterial sheaths were removed. One patient had pulse loss 4 h post procedure with a decrease in oximetry readings noted at this point on review. Weight-based heparin protocol was initiated, and a gradual improvement in oximetry readings was noted over the next 5 h. Vascular ultrasound 12 h later showed no evidence of arterial thrombus. NIRS may be helpful in identifying patients who are risk for developing arterial thrombus post cardiac catheterization and for monitoring response to therapy; however, further study in these patients is warranted.


Assuntos
Cateterismo Cardíaco/efeitos adversos , Extremidade Inferior/irrigação sanguínea , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Arteriopatias Oclusivas/diagnóstico , Encéfalo/irrigação sanguínea , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Oximetria/métodos , Trombose/etiologia , Trombose/prevenção & controle , Ultrassonografia Doppler
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.
Pediatr Cardiol ; 40(7): 1494-1502, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31367954

RESUMO

This observational study aimed to investigate the relationship between regional cerebral oxygen saturation (rSO2) during the 6-minute walk test (6-MWT) and the demographic/clinical features of patients with pulmonary arterial hypertension (PAH). Cerebral oxygenation was evaluated during the 6-MWT in 20 pediatric patients with PAH aged ≥ 7 years [13 male, 7 female; median age 12.25 (range 7-18) years]. In all patients, regional cerebral oxygen saturation    (rSO2), arterial oxygen saturation (SpO2), and heart rate (HR) were measured using near-infrared spectroscopy (NIRS) for 2 min before the test, during the 6-MWT test, and 2 min after the test. The relationship between the changes in rSO2, heart rate, and SpO2 values and clinical and laboratory features was compared statistically. The mean pulmonary arterial pressure (mPAP) was 77 (range 25-126) mmHg, and the median 6-minute walk distance (6-MWD) was 427.5 (300-570) m. The changes in rSO2 measurements ranged between 3.41 and 21.8%, and 70% of the patients had a greater than 10% decrease in rSO2 during the test compared with baseline. Eight patients showed a decrease in rSO2 without SpO2 changes. The present study demonstrated a significant decrease in cerebral oxygenation in pediatric patients with PAH during the 6-MWT. We hypothesized that using a combination of the 6-MWT and regional cerebral oxygenation monitoring in pediatric patients with PAH in order to evaluate exercise capacity, as a reflection of reduced daily activities, would provide more precise predictive values than the 6-MWT alone.


Assuntos
Hipertensão Pulmonar Primária Familiar/fisiopatologia , Oxigênio/sangue , Oxigênio/metabolismo , Teste de Caminhada/métodos , Adolescente , Adulto , Criança , Feminino , Frequência Cardíaca , Humanos , Masculino , Oximetria/métodos , Espectroscopia de Luz Próxima ao Infravermelho
14.
Comput Methods Programs Biomed ; 176: 43-49, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31200910

RESUMO

BACKGROUND AND OBJECTIVE: Fraction of Inspired Oxygen is one of the arbitrary set ventilator parameters which has critical influence on the concentration of blood oxygen. Normally mechanical ventilators providing respiratory assistance are tuned manually to supply required inspired oxygen to keep the oxygen saturation at the desired level. Maintaining oxygen saturation in the desired limit is so vital since excess supply of inspired oxygen leads to hypercapnia and respiratory acidosis which lead to increased risk in cell damage and death. On the other side a sudden drop in oxygen saturation will lead to severe cardiac arrest and seizure. Hence intelligent real time control of blood oxygen level saturation is highly significant for patients in intensive care units. METHODS: This paper gives statistical pair wise analysis for finding out deeply correlated physiological parameters from clinical data for fixing fuzzy variables. An advisory fuzzy controller using Mamdani model is developed with R programming to predict FiO2 which is to be delivered from the ventilator to maintain SaO2 with in required levels. RESULTS: Fuzzy variables for the fuzzy model is fixed using 75% of the clinical data collected. Remaining 25% of the data is used for checking the system. Compared the predictive output of the system with physicians' decisions and found to be accurate with less than five percentage error. CONCLUSIONS: Based on the comparison the system is proved to be effective and can be used as assist mode for physicians for effective decision making.


Assuntos
Sistemas de Apoio a Decisões Clínicas , Lógica Fuzzy , Oximetria/métodos , Oxigênio/sangue , Cuidados Críticos/métodos , Tomada de Decisões , Humanos , Unidades de Terapia Intensiva , Aprendizado de Máquina , Oxigênio/metabolismo , Troca Gasosa Pulmonar , Reprodutibilidade dos Testes , Respiração Artificial , Software , Terapia Assistida por Computador
15.
Compr Child Adolesc Nurs ; 42(sup1): 29-37, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31192737

RESUMO

Low-birth weight (LBW) infants have a major problem of sleep-awake and instability on physiological function. The objective of this study was to identify the effect of nesting with fixation and position on sleep-awake status and physiological function. This study used a crossover design and was conducted in a general hospital in Jakarta, involving 19 LBW infants who met the inclusion criteria. The intervention consisted of: nesting with fixation combined with prone position (NFPP) (A), nesting with fixation combined with quarter prone position (NFQP) (B), nesting with quarter prone position (NQP) (C), and control group (D). The results of this study showed that there was a significant difference between NFPP and NFQP compared to the control group in regard to quiet sleep and oxygen saturation (p < .05). Nesting with fixation combined with prone position was the most effective method to facilitate quiet sleep and the stability of SaO2 followed by nesting with fixation combined with quarter prone position as alternative intervention for LBW infant. Therefore, the application of nesting with fixation is needed.


Assuntos
Oximetria/métodos , Postura/fisiologia , Sono/fisiologia , Feminino , Humanos , Indonésia , Lactente , Recém-Nascido de Baixo Peso , Recém-Nascido , Masculino , Monitorização Fisiológica/métodos , Decúbito Ventral/fisiologia , Estudos Prospectivos , Sono/efeitos dos fármacos , Estatísticas não Paramétricas , Decúbito Dorsal/fisiologia
16.
Compr Child Adolesc Nurs ; 42(sup1): 1-8, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31192742

RESUMO

Respiratory disease in children can contribute to damaged alveoli, frailty of respiratory muscles, reduced lung function, impaired gas exchange, and gas retention in the airway. Such condition may lead to disruption of oxygen status. This study aimed to examine the effects of modified pursed lips breathing (PLB) by blowing into a water-filled bottle through a straw and a party whistle on the oxygenation status in children with oxygenation problems. This study used a quasi-experiment method with a pretest-posttest without a control group design approach. The sample consisted of 32 school-aged children and adolescents who were divided into two intervention groups. Group 1 underwent modified PLB by blowing into a water-filled bottle through a straw and Group 2 was provided with modified PLB by blowing a party whistle. The intervention was conducted one time in a day, in a rest time, for 10 min. The results showed that modified PLB by blowing into a water-filled bottle through a straw was more effective in reducing respiratory rate (RR) and improving oxygen saturation (SpO2) than modified PLB by blowing a party whistle. Modified PLB intervention by blowing into a water-filled bottle through a straw improved the oxygenation status of children affected by oxygenation problems. This intervention can be implemented as an independent nursing intervention to improve children's oxygenation status.


Assuntos
Exercícios Respiratórios/normas , Lábio/fisiologia , Oximetria/estatística & dados numéricos , Respiração , Adolescente , Exercícios Respiratórios/métodos , Criança , Avaliação Educacional/métodos , Feminino , Humanos , Masculino , Monitorização Fisiológica/métodos , Oximetria/métodos , Pediatria/métodos
17.
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
18.
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
19.
Invest Ophthalmol Vis Sci ; 60(6): 2083-2087, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31091315

RESUMO

Purpose: We study the relationship between retinal vessel oxygenation and the spatial distribution of retinal nonperfusion using ultrawide field angiography in eyes with retinal vascular diseases. Methods: This prospective single center study recruited 57 eligible eyes from 44 patients with retinal vascular diseases. Retinal oximetry measurements were obtained using the Oxymap T1 device to determine the arteriovenous (AV) difference. Retinal nonperfusion was measured from ultrawide field angiography images taken with the Optos 200TX system and superimposing the images with the concentric rings template to determine the area and distribution of retinal nonperfusion. Results: Seven (12.3%) eyes had a diagnosis of a branch or hemiretinal vein occlusion, 24 (42.1%) with central retinal vein occlusion and 26 (45.6%) with diabetic retinopathy (11 [19.3%] nonproliferative and 15 [26.3%] proliferative diabetic retinopathy). The correlation between the total area of retinal nonperfusion with the AV difference controlling for age was not statistically significant (R = -0.103, P = 0.449). However, when analyzing the correlation of AV difference with the area of retinal nonperfusion in the posterior pole controlling for age and peripheral nonperfusion, this was significant (R = -0.295, P = 0.029). This was not significant for the area of retinal nonperfusion in the periphery while controlling for posterior pole nonperfusion and age (R = 0.124, P = 0.368). Conclusions: Retinal nonperfusion has a negative correlation with AV difference measured on retinal oximetry. This correlation is significant in the posterior pole, but not in the peripheral retina.


Assuntos
Doenças Vasculares Periféricas/fisiopatologia , Doenças Retinianas/fisiopatologia , Vasos Retinianos/fisiopatologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Feminino , Angiofluoresceinografia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Oximetria/métodos , Estudos Prospectivos
20.
Anesth Analg ; 128(6): 1081-1088, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31094772

RESUMO

BACKGROUND: Near-infrared spectroscopy (NIRS) is used worldwide to monitor regional cerebral oxygenation (rScO2) during cardiopulmonary bypass (CPB). Intervention protocols meant to mitigate cerebral desaturation advocate to increase mean arterial pressure (MAP) when cerebral desaturation occurs. However, the isolated effect of MAP on rScO2 is uncertain. The aim of the present study was in a randomized, blinded design to elucidate the effect of 2 distinct levels of MAP on rScO2 values during CPB.We hypothesized that a higher MAP would be reflected in higher rScO2 values, lower frequency of patients with desaturation, and a less pronounced cerebral desaturation load. METHODS: This is a substudy of the Perfusion Pressure Cerebral Infarct trial, in which we investigated the impact of MAP levels during CPB on ischemic brain injury after cardiac surgery. Deviation in rScO2 was a predefined outcome in the Perfusion Pressure Cerebral Infarct trial. Patients were randomized to low MAP (LMAP; 40-50 mm Hg) or high MAP (HMAP; 70-80 mm Hg) during CPB. CPB pump flow was fixed at 2.4 L/min/m, and MAP levels were targeted using norepinephrine. Intraoperatively, NIRS monitoring was performed in a blinded fashion, with sensors placed on the left and right side of the patient's forehead. NIRS recordings were extracted for offline analysis as the mean value of left and right signal during prespecified periods. Mean rScO2 during CPB was defined as the primary outcome in the present study. RESULTS: The average MAP level during CPB was 67 mm Hg ± SD 5.0 in the HMAP group (n = 88) and 45 mm Hg ± SD 4.4 in the LMAP group (n = 88). Mean rScO2 was significantly lower in the HMAP group during CPB (mean difference, 3.5; 95% confidence interval, 0.9-6.1; P = .010). There was no difference in rScO2 values at specified time points during the intraoperative period between the 2 groups. Significantly more patients experienced desaturation below 10% and 20% relative to rScO2 baseline in the HMAP group (P = .013 and P = .009, respectively), and the cerebral desaturation load below 10% relative to rScO2 baseline was more pronounced in the HMAP group (P = .042). CONCLUSIONS: In a randomized blinded study, we observed that a higher MAP induced by vasopressors, with a fixed CPB pump flow, leads to lower mean rScO2 and more frequent and pronounced cerebral desaturation during CPB. The mechanism behind these observations is not clear. We cannot exclude extracranial contamination of the NIRS signal as a possible explanation. However, we cannot recommend increasing MAP by vasoconstrictors during cerebral desaturation because this is not supported by the findings of the present study.


Assuntos
Pressão Arterial , Procedimentos Cirúrgicos Cardíacos , Ponte Cardiopulmonar , Monitorização Intraoperatória/métodos , Oximetria/métodos , Espectroscopia de Luz Próxima ao Infravermelho , Adulto , Idoso , Algoritmos , Circulação Cerebrovascular , Interpretação Estatística de Dados , Método Duplo-Cego , Feminino , Lobo Frontal/patologia , Humanos , Hipóxia , Masculino , Pessoa de Meia-Idade , Oxigênio , Consumo de Oxigênio , Perfusão , Projetos de Pesquisa , Resultado do Tratamento , Vasoconstritores/farmacologia
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