Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 78
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Clin Transplant ; 37(12): e15139, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37725341

RESUMO

INTRODUCTION: This study examines whether the use of inpatient Continuous Glucose Monitors provides improved glycemic control over finger-stick glucose monitoring post-transplant. METHODS: This is a single-site, prospective randomized controlled trial of 40 patients receiving conventional finger-stick glucose monitoring or continuous monitoring using the Medtronic Guardian Sensor 3 during the first 5 days post-transplant. Included patients were adult renal transplant recipients with a diagnosis of diabetes. Assessed endpoints included post-transplant daily median glucose level, hyperglycemic (≥180 mg/dL) and hypoglycemic (≤80 mg/dL) episodes, number of post-transplant bacterial infections and length of stay. RESULTS: Groups were well matched in demographic variables. Median daily glucose was significantly lower in the intervention group. There were also significantly less episodes of hyperglycemia on postoperative days 2, 3, 4, and 5. There were no differences in the incidences of hypoglycemia, postoperative bacterial infections, or length of stay. CONCLUSION: In this randomized study, the use of a continuous glucose monitor to guide post-transplant glucose management significantly lowered the incidence of hyperglycemic episodes and median glucose levels through the first 5 days post-transplant without increasing the number of hypoglycemic episodes. The use of these devices can be considered in the immediate post-renal transplant setting.


Assuntos
Infecções Bacterianas , Hipoglicemia , Adulto , Humanos , Glicemia , Automonitorização da Glicemia , Monitoramento Contínuo da Glicose , Controle Glicêmico , Estudos Prospectivos , Hipoglicemiantes , Hipoglicemia/etiologia , Hipoglicemia/prevenção & controle , Hipoglicemia/diagnóstico , Insulina
2.
BMC Musculoskelet Disord ; 24(1): 351, 2023 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-37147702

RESUMO

BACKGROUND: Wound complication, skin blister formation in particular, causes devastating consequences after total knee arthroplasty (TKA). Negative Pressure Wound Therapy (NPWT) tries to improve wound management leading to decrease length of hospital stay and better clinical outcomes. Low body mass index (BMI) could play a part in wound recovery management although lacking evidence. This study compared length of hospital stay and clinical outcomes between NPWT and Conventional groups, and factors affected and how BMI affected. METHODS: This was a retrospective clinical record review of 255 (160 NPWT and 95 Conventional) patients between 2018 and 2022. Patient demographics including body mass index (BMI), surgical details (unilateral or bilateral), length of hospital stay, clinical outcomes including skin blisters occurrence, and major wound complications were investigated. RESULTS: Mean age of patients at surgery was 69.95 (66.3% were female). Patients treated with NPWT stayed significantly longer in the hospital after joint replacement (5.18 days vs. 4.55 days; p = 0.01). Significantly fewer patients treated with NPWT found to have blisters (No blisters: 95.0% vs. 87.4%; p = 0.05). In patients with BMI < 30, percentage of patients requiring dressing change was significantly lower when treated with NPWT than conventional (0.8% vs. 33.3%). CONCLUSION: Percentage of blisters occurrence in patients who underwent joint replacement surgery is significantly lower using NPWT. Patients using NPWT stayed significantly longer in the hospital after surgery because significant proportion received bilateral surgery. NPWT patients with BMI < 30 were significantly less likely to change wound dressing.


Assuntos
Artroplastia do Joelho , Tratamento de Ferimentos com Pressão Negativa , Humanos , Feminino , Masculino , Artroplastia do Joelho/efeitos adversos , Tratamento de Ferimentos com Pressão Negativa/efeitos adversos , Estudos Retrospectivos , Cicatrização , Infecção da Ferida Cirúrgica/etiologia , Infecção da Ferida Cirúrgica/epidemiologia
3.
BMC Musculoskelet Disord ; 24(1): 307, 2023 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-37076860

RESUMO

INTRODUCTION: Popularity of joint replacement surgery due to ever aging population surges the demand for a proper national joint registry. Our Chinese University of Hong Kong - Prince of Wales Hospital (CUHK-PWH) joint registry has passed the 30th year. The aims of this study are 1) summarize our territory-wide joint registry which has passed the 30th year since establishment and 2) compare our statistics with other major joint registries. METHODS: Part 1 was to review the CUHK-PWH registry. Demographic characteristics of our patients who underwent knee and hip replacements had been summarized. Part 2 was a series of comparisons with registries from Sweden, UK, Australia and New Zealand. RESULTS: CUHK-PWH registry captured 2889 primary total knee replacements (TKR) (110 (3.81%) revision) and 879 primary total hip replacements (THR) (107 (12.17%) revision). Median Surgery time of TKR was shorter than THR. Clinical outcome scores were much improved after surgery in both. Uncemented of hybrid in TKR were most popular in Australia (33.4%) and 40% in Sweden and UK. More than half of TKR and THR patients showed the highest percentage with ASA grade 2. New Zealand reflected the best cumulative percentage survival 20 years after surgery of 92.2%, 76.0%, 84.2% survivorship 20 years after TKR, unicompartmental knee replacement (UKR) and Hip. CONCLUSION: A worldwide accepted patient-reported outcome measure (PROM) is recommended to develop to make comparisons among registries and studies feasible. Completeness of registry data is important and useful to improve surgical performance through data comparisons from different regions. Funding from government on sustaining registries is reflected. Registries from Asian countries have yet to be grown and reported.


Assuntos
Artroplastia de Quadril , Artroplastia do Joelho , Idoso , Humanos , Artroplastia do Joelho/métodos , Articulação do Joelho/cirurgia , Extremidade Inferior/cirurgia , Sistema de Registros , Reoperação , Sobrevivência
4.
BMC Musculoskelet Disord ; 24(1): 510, 2023 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-37349732

RESUMO

BACKGROUND: Persistent anterior knee pain and subsequent patellofemoral joint (PFJ) osteoarthritis (OA) are common symptoms after anterior cruciate ligament reconstruction (ACLR). Quadriceps weakness and atrophy is also common after ACLR. This can be contributed by arthrogenic muscle inhibition and disuse, caused by joint swelling, pain, and inflammation after surgery. With quadriceps atrophy and weakness are associated with PFJ pain, this can cause further disuse exacerbating muscle atrophy. Herein, this study aims to identify early changes in musculoskeletal, functional and quality of health parameters for knee OA after 5 years of ACLR. METHODS: Patients treated with arthroscopically assisted single-bundle ACLR using hamstrings graft for more than 5 years were identified and recruited from our clinic registry. Those with persistent anterior knee pain were invited back for our follow-up study. For all participants, basic clinical demography and standard knee X-ray were taken. Likewise, clinical history, symptomatology, and physical examination were performed to confirm isolated PFJ pain. Outcome measures including leg quadriceps quality using ultrasound, functional performance using pressure mat and pain using self-reported questionnaires (KOOS, Kujala and IKDC) were assessed. Interobserver reproducibility was assessed by two reviewers. RESULTS: A total of 19 patients with unilateral injury who had undergone ACLR 5-years ago with persistent anterior knee pain participated in this present study. Toward the muscle quality, thinner vastus medialis and more stiffness in vastus lateralis were found in post-ACLR knees (p < 0.05). Functionally, patients with more anterior knee pain tended to shift more of their body weight towards the non-injured limb with increasing knee flexion. In accordance, rectus femoris muscle stiffness in the ACLR knee was significantly correlated with pain (p < 0.05). CONCLUSION: In this study, it was found that patients having higher degree of anterior knee pain were associated with higher vastus medialis muscle stiffness and thinner vastus lateralis muscle thickness. Similarly, patients with more anterior knee pain tended to shift more of their body weight towards the non-injured limb leading to an abnormal PFJ loading. Taken together, this current study helped to indicate that persistent quadriceps muscle weakness is potential contributing factor to the early development of PFJ pain.


Assuntos
Lesões do Ligamento Cruzado Anterior , Reconstrução do Ligamento Cruzado Anterior , Osteoartrite do Joelho , Articulação Patelofemoral , Humanos , Articulação Patelofemoral/patologia , Estudos Transversais , Seguimentos , Reprodutibilidade dos Testes , Lesões do Ligamento Cruzado Anterior/complicações , Lesões do Ligamento Cruzado Anterior/cirurgia , Articulação do Joelho/cirurgia , Osteoartrite do Joelho/diagnóstico por imagem , Osteoartrite do Joelho/etiologia , Osteoartrite do Joelho/cirurgia , Músculo Quadríceps/fisiologia , Dor/etiologia , Artralgia/diagnóstico , Artralgia/etiologia , Atrofia Muscular/etiologia , Reconstrução do Ligamento Cruzado Anterior/efeitos adversos , Força Muscular/fisiologia
5.
Liver Transpl ; 28(4): 593-602, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34626159

RESUMO

Liver transplantation (LT) listing criteria for hepatocellular carcinoma (HCC) remain controversial. To optimize the utility of limited donor organs, this study aims to leverage machine learning to develop an accurate posttransplantation HCC recurrence prediction calculator. Patients with HCC listed for LT from 2000 to 2016 were identified, with 739 patients who underwent LT used for modeling. Data included serial imaging, alpha-fetoprotein (AFP), locoregional therapies, treatment response, and posttransplantation outcomes. We compared the CoxNet (regularized Cox regression), survival random forest, survival support vector machine, and DeepSurv machine learning algorithms via the mean cross-validated concordance index. We validated the selected CoxNet model by comparing it with other currently available recurrence risk algorithms on a held-out test set (AFP, Model of Recurrence After Liver Transplant [MORAL], and Hazard Associated with liver Transplantation for Hepatocellular Carcinoma [HALT-HCC score]). The developed CoxNet-based recurrence prediction model showed a satisfying overall concordance score of 0.75 (95% confidence interval [CI], 0.64-0.84). In comparison, the recalibrated risk algorithms' concordance scores were as follows: AFP score 0.64 (outperformed by the CoxNet model, 1-sided 95% CI, >0.01; P = 0.04) and MORAL score 0.64 (outperformed by the CoxNet model 1-sided 95% CI, >0.02; P = 0.03). The recalibrated HALT-HCC score performed well with a concordance of 0.72 (95% CI, 0.63-0.81) and was not significantly outperformed (1-sided 95% CI, ≥0.05; P = 0.29). Developing a comprehensive posttransplantation HCC recurrence risk calculator using machine learning is feasible and can yield higher accuracy than other available risk scores. Further research is needed to confirm the utility of machine learning in this setting.


Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Transplante de Fígado , Humanos , Transplante de Fígado/efeitos adversos , Aprendizado de Máquina , Recidiva Local de Neoplasia/epidemiologia , Estudos Retrospectivos , Fatores de Risco , alfa-Fetoproteínas
6.
BMC Musculoskelet Disord ; 23(1): 222, 2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-35260136

RESUMO

BACKGROUND: A patient-reported outcome (PRO) tool which reflects the outcomes of patients underwent total knee arthroplasty (TKA) are important to be "ceiling effect free" which commonly used PRO tools face. Forgotten joint score-12 (FJS-12) has been proved to reduce or even free from ceiling effect. FJS-12 has been translated to different languages. The objectives of this study are to validate FJS-12 in Traditional Chinese-Hong Kong language and look for the goodness of FJS-12 still exist in this language adapted FJS-12 version. METHODS: FJS-12 was administered to 75 patients whose majority was obese underwent TKA between September 2019 and March 2020. Patients completed 3 sets of questionnaires (FJS-12, Oxford Knee Score (OKS), and Numeric Rating Scale (NRS)) twice, 2 weeks apart. Reliability, internal consistency, responsiveness, test-retest agreement and discriminant validity were evaluated. RESULTS: Reliability of FJS-12 showed moderate to excellent internal consistency (Cronbach's α = 0.870). Test-retest reliability of FJS-12 was good (ICC = 0.769). Bland-Altman plot showed good test-retest agreement. Construct validity in terms of correlations between FJS-12 and OKS, and FJS-12 and NRS were moderate at baseline (Pearson's coefficient r = 0.598) and good at follow-up (r = 0.879). Smallest detectable change (Responsiveness) was higher than MIC. Floor effect was none observed, and ceiling effect was low. Discriminant validity was found to have no significance. BMI (obesity) did not affect FJS-12 outcomes. CONCLUSIONS: The Traditional Chinese-Hong Kong version of FJS-12 showed good test-retest reliability, validity, responsiveness, BMI non-specific, with no floor and low ceiling effects for patients who underwent TKA. Sub-culture differences in individual PRO tools should be considered in certain ethnicities and languages.


Assuntos
Artroplastia do Joelho , Osteoartrite do Joelho , Comparação Transcultural , Hong Kong , Humanos , Articulação do Joelho/cirurgia , Idioma , Osteoartrite do Joelho/diagnóstico , Osteoartrite do Joelho/cirurgia , Reprodutibilidade dos Testes , Inquéritos e Questionários
7.
Res Sports Med ; : 1-13, 2022 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-36254570

RESUMO

Good preoperative knee function (KF) and quadriceps strength (QS) relate to good prognoses after anterior cruciate ligament reconstruction (ACLR). This study aimed to investigate the associations between patient characteristics, rate of torque development (RTD), voluntary activation (VA) of the quadriceps against preoperative KF and QS. A cross-sectional study was conducted. Forty patients with a primary, unilateral ACL injury who had finished the preoperative rehabilitation and scheduled for an ACLR were included. KF was evaluated using the International Knee Documentation Committee score. QS was measured by maximal voluntary isometric contractions. RTD was divided into the early (RTD0-50) and the late (RTD100-200) phases. Quadriceps VA was measured using the superimposed burst technique. Our results showed that patients with poor preoperative KF had more deficits in RTD0-50 (P = 0.025), higher BMI(P = 0.043), and more meniscus injuries (MI) (P = 0.001) than those with good KF. Patients with asymmetrical QS showed lower BMI (P = 0.020) and shorter time from injury (TFI) (P = 0.027) than those with symmetrical QS. Additionally, a higher pre-injury Tegner score combined with greater RTD100-200 contributed to greater QS on the injured limb (R2 = 0.357, P = 0.001). To conclude, BMI, TFI, concomitant MI, pre-injury physical activity level, and quadriceps RTD are related to QS and KF before ACLR.

8.
Am J Transplant ; 21(7): 2522-2531, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33443778

RESUMO

We compared the outcome of COVID-19 in immunosuppressed solid organ transplant (SOT) patients to a transplant naïve population. In total, 10 356 adult hospital admissions for COVID-19 from March 1, 2020 to April 27, 2020 were analyzed. Data were collected on demographics, baseline clinical conditions, medications, immunosuppression, and COVID-19 course. Primary outcome was combined death or mechanical ventilation. We assessed the association between primary outcome and prognostic variables using bivariate and multivariate regression models. We also compared the primary endpoint in SOT patients to an age, gender, and comorbidity-matched control group. Bivariate analysis found transplant status, age, gender, race/ethnicity, body mass index, diabetes, hypertension, cardiovascular disease, COPD, and GFR <60 mL/min/1.73 m2 to be significant predictors of combined death or mechanical ventilation. After multivariate logistic regression analysis, SOT status had a trend toward significance (odds ratio [OR] 1.29; 95% CI 0.99-1.69, p = .06). Compared to an age, gender, and comorbidity-matched control group, SOT patients had a higher combined risk of death or mechanical ventilation (OR 1.34; 95% CI 1.03-1.74, p = .027).


Assuntos
COVID-19 , Transplante de Órgãos , Adulto , Humanos , Terapia de Imunossupressão , SARS-CoV-2 , Transplantados
9.
BMC Geriatr ; 21(1): 2, 2021 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-33397330

RESUMO

BACKGROUND: Sarcopenia often accompanies osteoarthritis (OA), which is managed by total knee arthroplasty (TKA) in the late stage. Recent studies have suggested a higher risk of post-operative complications after TKA in sarcopenic OA subjects, but whether TKA can benefit them similar to non-sarcopenic subjects remains unexplored. This study aimed to examine the dynamic, mutual impact of sarcopenia and TKA in a one-year post-operative period. METHODS: This prospective cohort study was conducted between 2015 to 2018 at our hospital. Patients with end-stage OA of the knee waiting for TKA were recruited into the study. Primary outcome measures were change in muscle strength, mass and function. Secondary outcome measures were quality of life (QOL) measurements for pain, psychological and physical health. RESULTS: Fifty-eight patients were recruited, of which 79.3% were female and 32.8% already had sarcopenia at baseline. The average age of sarcopenic subjects and non-sarcopenic subjects was comparable (67.89 ± 7.07 vs. 67.92 ± 6.85; p = 0.99), but sarcopenic subjects had a lower body mass index (BMI) (25.64 ± 2.64 vs. 28.57 ± 4.04; p = 0.01). There was a statistically significant improvement in walking speed (10.24 ± 5.35 vs. 7.69 ± 2.68, p < 0.01) and muscle strength in both sarcopenic and non-sarcopenic patients after TKA. This was accompanied by an improvement trend in muscle mass in all subjects. There was no change in handgrip power before and after TKA and subsequent follow-up (19.31 ± 5.92 vs. 18.98 ± 6.37 vs. 19.36 ± 7.66; p = 0.97). QOL measured before, after and at follow-up with WOMAC (total: 42.27 ± 15.98 vs. 20.65 ± 15.24 vs. 16.65 ± 18.13) and SF12v2 (PCS: 33.06 ± 8.55 vs. 38.96 ± 8.01 vs. 40.67 ± 7.93) revealed progressive significant improvement (both comparisons p ≤ 0.01). Further analysis with the IPAQ also found increased engagement of high-intensity activities. CONCLUSIONS: This study showed that sarcopenia among patients with end-stage OA of the knee is not uncommon, but both sarcopenic and non-sarcopenic OA patients achieved significant clinical and functional improvement after TKA. Further studies with a larger sample size and different ethnicities could help ascertain a beneficial role of TKA in sarcopenic OA subjects. TRIAL REGISTRATION: Registry: ClinicalTrials.gov , Registration number: NCT03579329 . Date of registration: 6 July 2018. Retrospectively registered.


Assuntos
Artroplastia do Joelho , Osteoartrite do Joelho , Sarcopenia , Artroplastia do Joelho/efeitos adversos , Feminino , Força da Mão , Humanos , Masculino , Osteoartrite do Joelho/complicações , Osteoartrite do Joelho/diagnóstico , Osteoartrite do Joelho/epidemiologia , Estudos Prospectivos , Qualidade de Vida , Sarcopenia/diagnóstico , Sarcopenia/epidemiologia
10.
BMC Musculoskelet Disord ; 22(1): 476, 2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34030686

RESUMO

BACKGROUND: Vertebral compression fractures (VCFs) are the most common among all osteoporotic fractures. The body may compensate to the kyphosis from vertebral compression fractures with lordosis of the adjacent spinal segments, rotation of the pelvis, knee flexion and ankle dorsiflexion. However, the detailed degree of body compensation, especially the lower limb, remains uncertain. Herein, the aim of this study is to investigate the values of global sagittal alignments (GSA) parameters, including the spine, pelvis and lower limbs, in patients with and without VCFs, as well as to evaluate the effect of VCFs on various quality of life (QoL) parameters. METHODS: A cross-sectional study was conducted from May 2015 to June 2018. A total of 142 patients with VCFs aged over 60 years old and 108 age-matched asymptomatic controls were recruited. Whole body sagittal alignment including thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), sagittal vertical axis (SVA), T1-pelvic angle (TPA), knee-flex angle (KA) and ankle-flex angle (AA) were measured. In addition, lower back pain and quality of life were assessed using self-reported questionnaires. RESULTS: Compared to asymptomatic controls, patients with VCF showed significantly greater TK (33.4o ± 16.4o vs 28.4o ± 11.4o; p < 0.01), PT (25.4o ± 10.5o vs 16.6o ± 8.9o; p < 0.001), PI (54.6o ± 11.8o vs 45.8o ± 12.0o; p < 0.001), SVA (49.1 mm ± 39.6 mm vs 31.5 mm ± 29.3 mm; p < 0.01), and TPA (28.6o ± 10.8o vs 14.8o ± 8.6o; p < 0.001). Whereas for lower limb alignment, patients with VCF showed significantly higher KA (10.1o ± 7.8o vs 6.0o ± 6.4o; p < 0.001) and AA (7.0o ± 3.9o vs 4.8o ± 3.6o; p < 0.001) than controls. The number of VCF significantly correlated with lower limb alignments (KA and AA) and global sagittal balance (TPA). VCF patients showed poorer quality of life assessment scores in terms of SF-12 (30.0 ± 8.3 vs 72.4 ± 16.9; p < 0.001), ODI (37.8 ± 24.0 vs 18.7 ± 16.6; p < 0.001) and VAS (3.8 ± 2.8 vs 1.9 ± 2.2; p < 0.001). CONCLUSION: This is the first study to illustrate the abnormal lower limb alignment exhibited in patients with VCF. Patients with VCF showed an overall worse global sagittal alignment and decreased quality of life. Poorer global sagittal alignment of VCF patients also imply worse quality of life and more severe VCF.


Assuntos
Fraturas por Compressão , Lordose , Fraturas da Coluna Vertebral , Idoso , Estudos Transversais , Fraturas por Compressão/diagnóstico por imagem , Fraturas por Compressão/etiologia , Humanos , Lordose/diagnóstico por imagem , Extremidade Inferior/diagnóstico por imagem , Vértebras Lombares , Pessoa de Meia-Idade , Pelve/diagnóstico por imagem , Qualidade de Vida , Fraturas da Coluna Vertebral/diagnóstico por imagem , Coluna Vertebral
11.
Echocardiography ; 36(10): 1852-1858, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31536152

RESUMO

BACKGROUND: The incidence of Staphylococcus aureus infective endocarditis (IE) is steadily rising due to advances in health care delivery. Routine echocardiography is essential in the management of Staphylococcus aureus bacteremia (SAB). The aim of this retrospective cohort study was to characterize the real-world use of echocardiography in adult patients with SAB and native valve S aureus IE. METHODS: Using an academic hospital microbiological database, all cases of SAB in adults between 2010 and 2016 were identified. Demographic, echocardiographic, and clinical features were recorded. RESULTS: A total of 738 episodes of SAB were identified, of which 504 (68%) patients underwent transthoracic echocardiography (TTE) within 30 days. Of 73 patients with definite IE, 46 (63%) patients had definite IE diagnosed on the initial TTE. An additional 14 (19%) patients had definite IE diagnosed on repeat TTE, 6 (8%) on transesophageal echocardiography (TEE), and 7 (10%) were diagnosed without fulfilling Duke echocardiographic criteria. The yield of repeat TTE was comparable to that of TEE for identifying new vegetations not identified on the initial TTE (17% vs 21%, P = .78). CONCLUSIONS: Most cases of IE in SAB were identified using TTE alone, with repeat TTE improving the diagnostic yield in the setting of clinical decompensation.


Assuntos
Bacteriemia/diagnóstico por imagem , Ecocardiografia/métodos , Endocardite/diagnóstico por imagem , Infecções Estafilocócicas/diagnóstico por imagem , Bacteriemia/complicações , Estudos de Coortes , Ecocardiografia Transesofagiana , Endocardite/complicações , Feminino , Valvas Cardíacas/diagnóstico por imagem , Valvas Cardíacas/microbiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Infecções Estafilocócicas/complicações , Staphylococcus aureus
13.
Sensors (Basel) ; 18(2)2018 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-29443876

RESUMO

As Global Navigation Satellite System (GNSS) signals travel through the troposphere, a tropospheric delay occurs due to a change in the refractive index of the medium. The Precise Point Positioning (PPP) technique can achieve centimeter/millimeter positioning accuracy with only one GNSS receiver. The Zenith Tropospheric Delay (ZTD) is estimated alongside with the position unknowns in PPP. Estimated ZTD can be very useful for meteorological applications, an example is the estimation of water vapor content in the atmosphere from the estimated ZTD. PPP is implemented with different algorithms and models in online services and software packages. In this study, a performance assessment with analysis of ZTD estimates from three PPP online services and three software packages is presented. The main contribution of this paper is to show the accuracy of ZTD estimation achievable in PPP. The analysis also provides the GNSS users and researchers the insight of the processing algorithm dependence and impact on PPP ZTD estimation. Observation data of eight whole days from a total of nine International GNSS Service (IGS) tracking stations spread in the northern hemisphere, the equatorial region and the southern hemisphere is used in this analysis. The PPP ZTD estimates are compared with the ZTD obtained from the IGS tropospheric product of the same days. The estimates of two of the three online PPP services show good agreement (<1 cm) with the IGS ZTD values at the northern and southern hemisphere stations. The results also show that the online PPP services perform better than the selected PPP software packages at all stations.

14.
Sensors (Basel) ; 17(3)2017 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-28273798

RESUMO

The Global Positioning System (GPS) has been widely used in navigation, surveying, geophysical and geodynamic studies, machine guidance, etc. High-precision GPS applications such as geodetic surveying need millimeter and centimeter level accuracy. Since GPS signals are affected by atmospheric effects, methods of correcting or eliminating ionospheric and tropospheric bias are needed in GPS data processing. Relative positioning can be used to mitigate the atmospheric effect, but its efficiency depends on the baseline lengths. Air pollution is a serious problem globally, especially in developing countries that causes health problems to humans and damage to the ecosystem. Respirable suspended particles are coarse particles with a diameter of 10 micrometers or less, also known as PM10. Moreover, fine particles with a diameter of 2.5 micrometers or less are known as PM2.5. GPS signals travel through the atmosphere before arriving at receivers on the Earth's surface, and the research question posed in this paper is: are GPS signals affected by the increased concentration of the PM2.5/PM10 particles? There is no standard model of the effect of PM2.5/PM10 particles on GPS signals in GPS data processing, although an approximate generic model of non-gaseous atmospheric constituents (<1 mm) can be found in the literature. This paper investigates the effect of the concentration of PM2.5/PM10 particles on GPS signals and validates the aforementioned approximate model with a carrier-to-noise ratio (CNR)-based empirical method. Both the approximate model and the empirical results show that the atmospheric PM2.5/PM10 particles and their concentrations have a negligible effect on GPS signals and the effect is comparable with the noise level of GPS measurements.

15.
Can J Infect Dis Med Microbiol ; 2017: 8495307, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29230252

RESUMO

Point-of-care (POC) HIV testing has been shown to be an acceptable method for increasing HIV testing uptake. To date, no studies have examined the use of POC testing for routine HIV screening on the medicine inpatient unit. A prospective cross-sectional study was conducted over a three-month period in July, August, and October 2016 to evaluate the prevalence of undiagnosed HIV and the attitudes towards routine POC HIV testing. Patients admitted directly to medicine inpatient teaching units at a tertiary hospital in Winnipeg, Canada, were approached for participation. The POC HIV test was administered at the bedside. Reactive and indeterminate tests were confirmed with standard serological HIV testing. Participants were given a questionnaire regarding their attitudes towards POC testing on the unit. Although no cases of previously undiagnosed HIV were identified during the study period, only 35% of participants were found to have ever had HIV testing previously. The majority of participants were satisfied with the POC testing experience and would choose to have the POC testing again. Overall, the low rate of outpatient testing highlights the need for routine HIV testing on an inpatient basis.

16.
Sensors (Basel) ; 16(11)2016 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-27854324

RESUMO

Twelve GPS Block IIF satellites, out of the current constellation, can transmit on three-frequency signals (L1, L2, L5). Taking advantages of these signals, Three-Carrier Ambiguity Resolution (TCAR) is expected to bring much benefit for ambiguity resolution. One of the research areas is to find the optimal combined signals for a better ambiguity resolution in geometry-free (GF) and geometry-based (GB) mode. However, the existing researches select the signals through either pure theoretical analysis or testing with simulated data, which might be biased as the real observation condition could be different from theoretical prediction or simulation. In this paper, we propose a theoretical and empirical integrated method, which first selects the possible optimal combined signals in theory and then refines these signals with real triple-frequency GPS data, observed at eleven baselines of different lengths. An interpolation technique is also adopted in order to show changes of the AR performance with the increase in baseline length. The results show that the AR success rate can be improved by 3% in GF mode and 8% in GB mode at certain intervals of the baseline length. Therefore, the TCAR can perform better by adopting the combined signals proposed in this paper when the baseline meets the length condition.

18.
Cardiovasc Ultrasound ; 13: 10, 2015 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-25888874

RESUMO

BACKGROUND: A subset of patients receiving first-time permanent pacemakers (PPM) may also benefit from an implantable cardioverter defibrillator (ICD) based on the presence of left ventricular systolic dysfunction (LVSD). Routine screening using pocket-sized echocardiography (PSE) may be useful in identifying such patients. OBJECTIVE: To determine whether PSE can be used by an inexperienced sonographer to adequately screen for LVSD in a patient population receiving a first-time PPM. METHODS: A sonographic trainee (medical student) acquired images using PSE, which were then evaluated by an experienced echocardiologist for both image quality and presence of LVSD. The sensitivity and specificity of assessment by the inexperienced sonographer was compared to the level 3 echocardiologist. RESULTS: The patient population included 71 individuals (66% male, mean age 77 ± 12 years). Interpretable images where left ventricular ejection fraction (LVEF) could be adequately assessed were obtained in 93% of the patient population. As compared with the echocardiologist, the sonographic trainee had a sensitivity of 60% and a specificity of 98% in detecting LVSD. CONCLUSIONS: For patients receiving first-time PPM, the use of PSE by a sonographic trainee combined with interpretation by an experienced imaging cardiologist can triage for the need to perform standard transthoracic echocardiography (sTTE) by determining the presence of LVSD.


Assuntos
Ecocardiografia/instrumentação , Ecocardiografia/métodos , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/prevenção & controle , Marca-Passo Artificial , Disfunção Ventricular Esquerda/diagnóstico por imagem , Idoso , Desenho de Equipamento , Análise de Falha de Equipamento , Feminino , Insuficiência Cardíaca/complicações , Humanos , Masculino , Miniaturização , Seleção de Pacientes , Sistemas Automatizados de Assistência Junto ao Leito , Cuidados Pré-Operatórios , Implantação de Prótese/métodos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Volume Sistólico , Disfunção Ventricular Esquerda/etiologia , Disfunção Ventricular Esquerda/prevenção & controle
19.
Ann Surg Oncol ; 21(7): 2420-8, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24595797

RESUMO

BACKGROUND: Biological characteristics of colorectal cancer liver metastases (CRCLM) are increasingly recognized as major determinants of patient outcome. The purpose of this study was to evaluate the prognostic value of metabolic response to preoperative chemotherapy as quantified by (18)F-FDG positron emission tomography (PET) for patients undergoing liver resection of CRCLM. METHODS: All patients (n = 80) who had staging PET before liver resection for CRCLM at Austin Health in Melbourne between 2004 and 2011 were included. Thirty-seven patients had PET and CT imaging before and after preoperative chemotherapy. Semiquantitative PET parameters-maximum standardized uptake variable (SUVmax), metabolic tumour volume (MTV), and total glycolytic volume (TGV)-were derived. Metabolic response was determined by the proportional change in PET parameters (∆SUVmax, ∆MTV, ∆TGV). Prognostic scores, CT RECIST response, and tumour regression grading (TRG) were also assessed. Correlation to recurrence-free (RFS) and overall survival (OS) was assessed using Kaplan-Meier survival and multivariate analysis. RESULTS: Semiquantitative parameters on staging PET before chemotherapy were not predictive of prognosis, whereas all parameters after chemotherapy were prognostic for RFS and OS. Only ∆SUVmax was predictive of RFS and OS on multivariate analysis. Patients with metabolically responsive tumours had an OS of 86 % at 3 years vs. 38 % with nonresponsive or progressive tumours (p = 0.003). RECIST and TRG did not predict outcome. CONCLUSIONS: Tumour metabolic response to preoperative chemotherapy as quantified by PET is predictive of prognosis in patients undergoing resection of CRCLM. Assessing metabolic response uniquely characterizes tumour biology, which may allow future optimization of patient and treatment selection.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/terapia , Hepatectomia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias Colorretais/mortalidade , Neoplasias Colorretais/patologia , Terapia Combinada , Feminino , Fluordesoxiglucose F18 , Fluoruracila/administração & dosagem , Seguimentos , Humanos , Leucovorina/administração & dosagem , Neoplasias Hepáticas/mortalidade , Neoplasias Hepáticas/secundário , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Compostos Organoplatínicos/administração & dosagem , Oxaliplatina , Tomografia por Emissão de Pósitrons , Prognóstico , Estudos Prospectivos , Curva ROC , Compostos Radiofarmacêuticos , Taxa de Sobrevida , Tomografia Computadorizada por Raios X , Adulto Jovem
20.
J Med Imaging Radiat Sci ; 55(2S): S17-S25, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38307769

RESUMO

Positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) has recently emerged as an increasingly used alternative and supplementary imaging modality for the diagnosis of infective endocarditis. 18F-FDG PET/CT imaging for IE is given a Class I recommendation (level of evidence B) and is therefore recommended in cases of possible prosthetic valve IE to both detect valvular lesions, as well as confirm the diagnosis of IE. They have also given a class I recommendation (level of evidence B) for brain and whole-body 18F-FDG PET/CT and/or MRI imaging to detect peripheral lesions for patients with either native or prosthetic valve IE. Molecular imaging is playing an increasingly important role in the diagnosis and management of patients with IE. The important role of 18F-FDG PET/CT imaging has been acknowledged by recent guideline updates. These advanced imaging tests are not supplanting the role of echocardiography in the diagnostic pathway for IE. Rather, they are additional tools that are available where the diagnosis is complicated, difficult, or uncertain.


Assuntos
Endocardite , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Humanos , Endocardite/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Tomografia por Emissão de Pósitrons/métodos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA