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1.
Pediatr Qual Saf ; 8(5): e680, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37780601

RESUMO

Background: In 2013, Nationwide Children's Hospital's (NCH) Quality Tool School (QTS) was created as an initial Quality Improvement educational series, composed of three separate classes, totaling 5.5 hours of hands-on QI training. QTS complemented the NCH 40-hour Quality Improvement Essentials course. Methods: Over 10 years, the series went through three phases of aims: Phase 1: develop and implement three core courses (Project Tools, Excel, and Control Charts); Phase 2: have participants complete the entire series of all three classes; Phase 3: have participants who complete the entire series of all three classes demonstrate the application of learning through involvement in a quality improvement project. Results: Since initiation, QTS has provided an educational entry point for 1428 NCH employees to participate in QI projects and teams. QTS has shown statistically significant improvement in 2 of the 3 principal aims. The Phase 1 metric of average monthly one-class participation completion percentage showed a statistically significant centerline shift from 9 to 16 students in October 2018. The Phase 3 metric Percentage of QTS participants completing the QTS series of classes and then participating in a QI team began in 2016 with a baseline of 42%. A centerline shift from 42% to 63% occurred in Q4 2018. Conclusions: QTS can provide QI education to healthcare system employees using limited resources. Organizations that strategically integrate a culture of QI into core beliefs can realize substantial improvement gains.

2.
Pediatr Qual Saf ; 8(5): e630, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37780603

RESUMO

Introduction: Failure to recognize and mitigate critical patient deterioration remains a source of serious preventable harm to hospitalized pediatric cardiac patients. Emergency transfers (ETs) occur 10-20 times more often than code events outside the intensive care unit (ICU) and are associated with morbidity and mortality. This quality improvement project aimed to increase days between ETs and code events on an acute care cardiology unit (ACCU) from a baseline median of 17 and 32 days to ≥70 and 90 days within 12 months. Methods: Institutional leaders, cardiology-trained physicians and nurses, and trainees convened, utilizing the Institution for Healthcare Improvement model to achieve the project aims. Interventions implemented focused on improving situational awareness (SA), including a "Must Call List," evening rounds, a visual management board, and daily huddles. Outcome measures included calendar days between ETs and code events in the ACCU. Process measures tracked the utilization of interventions, and cardiac ICU length of stay was a balancing measure. Statistical process control chart methodology was utilized to analyze the impact of interventions. Results: Within the study period, we observed a centerline shift in primary outcome measures with an increase from 17 to 56 days between ETs and 32 to 62 days between code events in the ACCU, with sustained improvement. Intervention utilization ranged from 87% to 100%, and there was no observed special cause variation in our balancing measure. Conclusions: Interventions focused on improving SA in a particularly vulnerable patient population led to sustained improvement with reduced ETs and code events outside the ICU.

3.
Pediatr Qual Saf ; 8(2): e644, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37051404

RESUMO

Abusive injuries can go unrecognized or improperly managed by medical providers. This study sought to standardize the nonaccidental trauma (NAT) workup and improve NAT evaluation completion for children <7 months with concerning injuries in the pediatric emergency department (PED) and inpatient settings at an urban, tertiary care children's hospital. Methods: The quality improvement (QI) team created hospital guidelines for suspected NAT, including age-based recommendations (care bundle). The team embedded an order for NAT evaluation into the electronic health record (EHR). The QI team provided education on child abuse identification and evaluation across the hospital. Hospital providers received written guides focused on enhancing communication with families. Outcome measures included monthly NAT bundle use and cases between incomplete bundles in children with suspicious injuries. Chart review of incomplete bundles helped accurately identify patients who needed NAT bundles and improved accurate NAT bundle completion for appropriate patients. Results: Appropriate NAT bundle completion increased from 31% during the baseline period in January 2019 to 100% in April 2020 and remained at 100% for the remainder of the study period, ending June 2021. The number of patients between missed bundles was 11 from August 2019 until March 2020, when it increased to 583. There were no missed bundles from March 2020 through June 2021. Conclusions: Standardizing NAT evaluation and creating a NAT care bundle to facilitate the appropriate evaluation preceded an increase in appropriate bundle completion in patients <7 months old with possible NAT in the PED and inpatient units.

4.
J Pediatr ; 258: 113441, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37088183

RESUMO

OBJECTIVE: To address a known nutritional deficit and enhance the overall health of critically ill babies, this project sought to increase the percentage of cardiothoracic intensive care unit (CTICU) neonates consuming human milk from a 2019 baseline of 55% to 75% by December 2020 and 90% by December 2021. STUDY DESIGN: This was a quality improvement initiative targeted to all neonates admitted to the CTICU, with baseline data obtained from January 2019 through February 2020. We implemented 11 interventions from March 2020 to January 2022 to address the key drivers of "education of parents and providers," "environment/equipment," and "process." We tracked the monthly percentage of neonates who were human milk fed with a statistical process control p-chart. The balancing measure of critical human milk feeding errors was also monitored. RESULTS: The baseline percentage of CTICU neonates consuming human milk was 55%. This percentage increased to 73% by the end of 2020 and 92% by the year end 2021. Most neonates who received human milk were fed mother's milk with a minority receiving donor human milk. The number of aborted, critical human milk administration errors decreased during the intervention period. CONCLUSIONS: In this quality improvement initiative, we significantly increased the percentage of CTICU neonates consuming human milk without an increase in critical human milk errors. Interventions directly increasing the ease with which lactating mothers can provide/store their milk were likely the most effective.


Assuntos
Leite Humano , Melhoria de Qualidade , Recém-Nascido , Feminino , Criança , Humanos , Lactação , Unidades de Terapia Intensiva Neonatal , Mães , Aleitamento Materno
5.
Pediatr Qual Saf ; 7(4): e575, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35765568

RESUMO

Central line-associated bloodstream infections (CLABSIs) are preventable events that increase morbidity and mortality. The objective of this quality project was to reduce the incidence of CLABSIs in a pediatric cardiothoracic intensive care unit. Methods: Institutional review of an unacceptably high rate of CLABSIs led to the implementation of 4 new interventions. These interventions included: the use of sequential cleaning between line accesses, Kamishibai card audits, central line utilization and entry audits, and proctored simulation of line access. Results: There was a reduction in CLABSI rate from 1.52 per 1,000 central line days in 2018 to 0.37 per 1,000 central line days in 2020 and 0.32 in 2021. Additionally, central line days per 100 patient days decreased from 77 to 70 days over the study period. The cardiothoracic intensive care unit went 389 days without a CLABSI from October 2020 to November 2021. Conclusions: Implementation of multiple interventions led to a successful reduction in the incidence of CLABSIs in our unit, with a sustained reduction over 1 year.

6.
Pediatr Qual Saf ; 6(6): e493, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34934877

RESUMO

Congenital heart disease (CHD), the most common congenital malformation, often requires surgical correction. As surgical mortality rates are low, a common quality marker linked with surgical outcomes is hospital length of stay (LOS). Reduced LOS is associated with better long-term outcomes, reduced hospital-acquired complications, and improved patient-family satisfaction. This project aimed to reduce aggregate median postoperative LOS for four CHD lesions from a baseline of 6.2 days by 10%. METHODS: This single-center study utilized the Institute for Healthcare Improvement model to achieve the project aim. A diuretic wean protocol implemented in April 2018 entailed weaning to a homegoing diuretic regimen upon transfer from the cardiac intensive care unit to the inpatient step-down unit. A discharge milestone checklist implemented in September 2018 contained milestones necessary for discharge and an anticipated date of discharge. Outcome measures included aggregate median postoperative LOS and ∆LOS. Balancing measures included cardiac intensive care unit bounce back, pleural chest tube replacement, and readmission rates. RESULTS: Our baseline aggregate median postoperative LOS for the lesions studied was 6.2 days. Following diuretic protocol implementation, the aggregate median LOS decreased to 4.4 days. Baseline ∆LOS decreased from 5.5 to 0.42 days. Postoperative cost fell by an average of $11,874. Balancing measures demonstrated no unintended consequences. CONCLUSIONS: Implementation of a diuretic wean protocol led to sustained improvement in postoperative LOS, and ∆LOS in a subset of CHD patients with no unintended consequences supporting that standardization of postoperative care is effective for improvement efforts and can reduce overall practice variation.

7.
Pediatr Qual Saf ; 6(4): e438, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34345751

RESUMO

INTRODUCTION: High-cost medication administration, despite lacking evidence for use, results in poor healthcare value. This work aimed to reduce dornase-alfa utilization in critically ill mechanically ventilated children. METHODS: The project employed an observational pre-post design to develop a value-based clinical pathway to guide provider choice in mucolytic utilization in a quaternary pediatric intensive care unit. This pathway was designed to continue using low-cost mucolytic aerosols (hypertonic saline, N-acetylcysteine) but decrease new starts and total doses per 100 patient days (P100PD) dornase-alfa among patients for whom there is little to no supporting evidence. Interventions included a departmental journal club for fellow and attending physicians and a rolling introduction of the pathway to residents and respiratory therapists. Control charts serially tracked ordering changes and location-specific dornase alfa orders. RESULTS: New dornase-alfa starts P100PD decreased by 53% (1.17-0.55), and total doses P100PD decreased by 75% (16-4). N-acetylcysteine ordering more than doubled; however, total doses of P100PD remained unchanged after the intervention. The use of 3% sodium chloride increased significantly from 0.28 to 4.15 new starts and 4.37 to 38.84 total doses P100PD. Mechanical ventilation days P100PD decreased, suggesting there were no measured adverse effects of pathway implementation. The reduction in dornase-alfa utilization resulted in a cumulative and sustained 59% mucolytic cost reduction ($2183.08-$885.77 P100PD). CONCLUSION: A clinical pathway prioritizing pharmacoeconomics when evidence for use is lacking can improve health care value without adversely affecting patient outcomes.

8.
Pediatr Qual Saf ; 4(3): e162, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31579864

RESUMO

BACKGROUND: Pressure ulcer (PU) is an injury to skin or underlying tissue as a result of pressure or pressure with shear stress. We classify PUs by the level of tissue injury: stage I-IV, unstageable, suspected deep tissue injury. This quality project was aimed to reduce the incidence of PUs > stage II in the cardiothoracic intensive care unit. METHODS: We reviewed PUs > stage II from March 2010 to December 2017. Interventions included: PU bundle (April 2010, revised January 2013); multidisciplinary huddles for PUs > stage II (October 2011); multidisciplinary weekly skin rounds (March 2010, revised August 2012); unit specific workgroup (October 2012); caregiver input form (December 2012). The PU bundle included diaper barrier cream, pulse oximeter probe rotation, turning schedule, pressure reduction surfaces, heel pressure release, head of the bed elevation. RESULTS: Between 2010 and 2014, PUs decreased from 15.7 events per 1,000 patient days to a new baseline of 2.9 events per 1,000 patient days. We have sustained this rate for 3 years. PUs related to immobility decreased from 35 in 2010-2011 to 4 in 2016-2017. PU related to medical devices decreased from 34 in 2010-2011 to 15 in 2016-2017. CONCLUSIONS: Institution of PU bundle, multidisciplinary weekly skin rounds, and huddles for PUs > stage II reduced PUs related to immobility, allowed for earlier identification of stage II PUs and reduced stage III PUs. Challenges remain in reducing PUs related to medical devices. Importantly, we sustained this improvement over the past 3 years.

9.
J Pediatr Orthop ; 39(8): e586-e591, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31393294

RESUMO

BACKGROUND: Multiple randomized trials have showed equivalent outcomes and improved patient/family satisfaction using a removable brace to treat pediatric distal radius buckle fractures (DRBF). We tested the hypothesis that we could use quality improvement (QI) methodology to increase the proportion of patients with DRBF treated with removable braces at 2 tertiary care orthopaedic clinics from a baseline of 34.8% to 80%. METHODS: Clinic billing records were reviewed monthly to determine treatment (brace vs. cast) of DRBF and tracked using control charts (p-chart). Balance measures including correct application of the diagnostic criteria and algorithm were monitored. Process measures including the number of follow-up visits, radiographs obtained, and total cost of treatment were collected. Baseline data were obtained over a 3-month period, followed by a 12-month period of interventions using Plan-Do-Study-Act cycles targeting both individuals and groups of providers. RESULTS: The proportion of DRBF treated in a brace increased from a combined baseline of 34.8% to a combined 84% at the end of the study period. Following intervention, 83% (15/18) of providers began using braces for a majority of patients (defined as >67%), with only 1 provider continuing to use casts 100% of the time. Patient preference was cited as the most common reason for use of cast treatment. There was a significant decrease in the number of radiographs obtained at 1 of 2 institutions. The charges for brace treatment averaged $630 less per patient than for cast treatment, leading to an estimated medical-cost savings of $205,000 following intervention. CONCLUSIONS: Implementation of brace treatment for pediatric DRBF using QI methodology resulted in a shift toward brace treatment in the majority of patients, leading to substantial medical and nonmedical cost savings. Although patient preference was cited as the most common reason for persistent cast treatment, the data show the use of cast treatment to be more dependent upon individual provider preference. LEVEL OF EVIDENCE: Level II-therapeutic.


Assuntos
Braquetes/tendências , Moldes Cirúrgicos/tendências , Melhoria de Qualidade , Fraturas do Rádio/terapia , Braquetes/economia , Moldes Cirúrgicos/economia , Criança , Redução de Custos , Medicina Baseada em Evidências , Humanos , Satisfação do Paciente , Radiografia , Fraturas do Rádio/diagnóstico por imagem , Fraturas do Rádio/economia
10.
Pediatr Qual Saf ; 4(6): e237, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32010863

RESUMO

Decreasing practice variation and following evidence-based clinical guidelines improve patient outcomes and often reduce cost. Essentially all postsurgical cardiac patients require diuretics. The approach to diuresis in the pediatric cardiothoracic intensive care unit (CTICU) is not standardized. Our objective was to develop and implement guidelines for diuretic utilization in the CTICU to reduce high charge medication utilization while maintaining the delivery of high-quality care. METHODS: Two of the top 10 medications by charge in the CTICU during 2016 were diuretics [fenoldopam and intravenous (IV) chlorothiazide]. Standardized diuretic utilization guidelines were developed to reduce the utilization of fenoldopam and IV chlorothiazide. We implemented guidelines in April 2017. The utilization of fenoldopam and IV chlorothiazide, as well as overall diuretic charges, before and after guideline implementation were compared. RESULTS: We normalized all comparisons to 100 CTICU patient-days. Fenoldopam starts were reduced from 1.1 in 2016 to 0.03 in 2019 (through February); days of fenoldopam use were reduced from 4 in 2016 to 0.15 days in 2019 (through February); IV chlorothiazide doses decreased from 20 in 2016 to 8 in 2019 (through February). These changes reduced the mean charges for diuretics from $25,762 in 2016 to $8,855 in 2019 (through February). CTICU average daily census did not change significantly during the study period (12.8 in 2016 vs 11.8 in 2018). CONCLUSION: Value-added implementation of standardized diuretic utilization guidelines in the CTICU successfully reduced the use of high-charge diuretics without unfavorably impacting the quality of care delivery.

11.
J Pediatr Orthop ; 38(2): e43-e49, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29227371

RESUMO

BACKGROUND: Casts, while frequently used as routine treatment in pediatric orthopaedic practice, are not without complications. At our large tertiary care pediatric hospital, the baseline rate of all casting complications was 5.6 complications per 1000 casts applied (0.56%). We tested the hypothesis that we could use quality improvement (QI) methodology to decrease the overall cast complication rate and improve patient care. METHODS: We initiated a QI program implementing concepts derived from the Institute for Healthcare Improvement models, including Plan-Do-Study-Act cycles, to decrease our cast complication rate. A resident casting education program was developed with a competency "checklist" to ensure that casts are applied, bivalved, and removed in a safe and standardized manner to prevent patient harm. AquaCast Saw Stop Protective Strips were required to be applied with every cast application. A review of our facility's processes and procedures determined adequate measures were in place to effectively manage inventory and maintenance of cast-saw blades. RESULTS: With the multimodal QI intervention, our cast complication rate was reduced to 1.61 complications per 1000 applications, a >90% improvement. CONCLUSIONS: Implementation of QI concepts to perform a QI initiative resulted in a shift toward fewer cast complications, leading to overall improved patient care at a large tertiary pediatric hospital. LEVEL OF EVIDENCE: Level II-prospective cohort study.


Assuntos
Moldes Cirúrgicos/efeitos adversos , Ortopedia/educação , Melhoria de Qualidade , Contenções/efeitos adversos , Moldes Cirúrgicos/normas , Lista de Checagem , Criança , Hospitais Pediátricos , Humanos , Estudos Prospectivos , Contenções/normas
12.
Ecotoxicol Environ Saf ; 144: 564-571, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28688358

RESUMO

Information on trace element pollution in the terrestrial environment and its biota is limited compared to the marine environment. In the present study, we collected body feathers and blood of 37 Northern goshawk (Accipiter gentilis) nestlings from Tromsø (northern Norway), Trondheim (central Norway), and Murcia (southeastern Spain) to study regional exposure, hypothesizing the potential health risks of metals and other trace elements. Blood and body feathers were analyzed by a high resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) for aluminum (Al), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), mercury (Hg) and lead (Pb). The influence of regional differences, urbanization and agricultural land usage in proximity to the nesting Northern goshawks was investigated using particular spatial analysis techniques. Most trace elements were detected below literature blood toxicity thresholds, except for elevated concentrations (mean ± SD µgml-1 ww) found for Zn (5.4 ± 1.5), Cd (0.00023 ± 0.0002), and Hg (0.021 ± 0.01). Corresponding mean concentrations in feathers (mean ± SD µgg-1 dw) were 82.0 ± 12.4, 0.0018 ± 0.002, and 0.26 ± 0.2 for Zn, Cd and Hg respectively. Multiple linear regressions indicated region was a significant factor influencing Al, Zn, Se and Hg feather concentrations. Blood Cd and Hg concentrations were significantly influenced by agricultural land cover. Urbanization did not have a significant impact on trace element concentrations in either blood or feathers. Overall metal and trace element levels do not indicate a high risk for toxic effects in the nestlings. Levels of Cd in Tromsø and Hg in Trondheim were however above sub-lethal toxic threshold levels. For holistic risk assessment purposes it is important that the concentrations found in the nestlings of this study indicate that terrestrial raptors are exposed to various trace elements.


Assuntos
Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Falconiformes/sangue , Plumas/química , Metais Pesados/análise , Oligoelementos/análise , Animais , Arsênio/análise , Poluentes Ambientais/sangue , Modelos Lineares , Metais Pesados/sangue , Noruega , Selênio/análise , Espanha , Oligoelementos/sangue
13.
J Neural Eng ; 8(4): 046006, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21628771

RESUMO

Microelectrode recording (MER) along surgical trajectories is commonly applied for refinement of the target location during deep brain stimulation (DBS) surgery. In this study, we utilize automatically detected MER features in order to locate the subthalamic nucleus (STN) employing an unsupervised algorithm. The automated algorithm makes use of background noise level, compound firing rate and power spectral density along the trajectory and applies a threshold-based method to detect the dorsal and the ventral borders of the STN. Depending on the combination of measures used for detection of the borders, the algorithm allocates confidence levels for the annotation made (i.e. high, medium and low). The algorithm has been applied to 258 trajectories obtained from 84 STN DBS implantations. MERs used in this study have not been pre-selected or pre-processed and include all the viable measurements made. Out of 258 trajectories, 239 trajectories were annotated by the surgical team as containing the STN versus 238 trajectories by the automated algorithm. The agreement level between the automatic annotations and the surgical annotations is 88%. Taking the surgical annotations as the golden standard, across all trajectories, the algorithm made true positive annotations in 231 trajectories, true negative annotations in 12 trajectories, false positive annotations in 7 trajectories and false negative annotations in 8 trajectories. We conclude that our algorithm is accurate and reliable in automatically identifying the STN and locating the dorsal and ventral borders of the nucleus, and in a near future could be implemented for on-line intra-operative use.


Assuntos
Eletrodos Implantados , Microeletrodos , Neurônios/fisiologia , Ruído/efeitos adversos , Núcleo Subtalâmico/fisiologia , Algoritmos , Artefatos , Estimulação Encefálica Profunda/métodos , Humanos , Reprodutibilidade dos Testes , Processamento de Sinais Assistido por Computador , Substância Negra/anatomia & histologia , Substância Negra/fisiologia , Núcleo Subtalâmico/anatomia & histologia , Núcleo Subtalâmico/cirurgia
14.
Med Biol Eng Comput ; 47(7): 791-800, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19468773

RESUMO

Extra-cellular neuro-recording signals used for functional mapping in deep brain stimulation (DBS) surgery and invasive brain computer interfaces, may suffer from poor signal to noise ratio. Therefore, a reliable automatic noise estimate is essential to extract spikes from recordings. We show that current methods are biased toward overestimation of noise-levels with increasing neuronal activity or artifacts. An improved and novel method is proposed that is based on an estimate of the mode of the distribution of the signal envelope. Our method makes use of the inherent characteristics of the noise distribution. For band-limited Gaussian noise the envelope of the signal is known to follow the Rayleigh distribution. The location of the peak of this distribution provides a reliable noise-level estimate. It is demonstrated that this new 'envelope' method gives superior performance both on simulated data, and on actual micro-electrode recordings made during the implantation surgery of DBS electrodes for the treatment of Parkinson's disease.


Assuntos
Mapeamento Encefálico/métodos , Estimulação Encefálica Profunda/métodos , Processamento de Sinais Assistido por Computador , Artefatos , Humanos , Cuidados Intraoperatórios/métodos , Microeletrodos , Doença de Parkinson/fisiopatologia , Doença de Parkinson/cirurgia
15.
Neuroimage ; 37(4): 1384-95, 2007 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-17689986

RESUMO

In order to study the temporal activation course of visual areas V1 and V5 in response to a motion stimulus, a random dots kinematogram paradigm was applied to eight subjects while magnetic fields were recorded using magnetoencephalography (MEG). Sources generating the registered magnetic fields were localized with Magnetic Field Tomography (MFT). Anatomical identification of cytoarchitectonically defined areas V1/V2 and V5 was achieved by means of probabilistic cytoarchitectonic maps. We found that the areas V1/V2 and V5+ (V5 and other adjacent motion sensitive areas) exhibited two main activations peaks at 100-130 ms and at 140-200 ms after motion onset. The first peak found for V1/V2, which corresponds to the visual evoked field (VEF) M1, always preceded the peak found in V5+. Additionally, the V5+ peak was correlated significantly and positively with the second V1/V2 peak. This result supports the idea that the M1 component is generated not only by the visual area V1/V2 (as it is usually proposed), but also by V5+. It reflects a forward connection between both structures, and a feedback projection to V1/V2, which provokes a second activation in V1/V2 around 200 ms. This second V1/V2 activation (corresponding to motion VEF M2) appeared earlier than the second V5+ activation but both peaked simultaneously. This result supports the hypothesis that both areas also generate the M2 component, which reflects a feedback input from V5+ to V1/V2 and a crosstalk between both structures. Our study indicates that during visual motion analysis, V1/V2 and V5+ are activated repeatedly through forward and feedback connections and both contribute to m-VEFs M1 and M2.


Assuntos
Percepção de Movimento/fisiologia , Córtex Visual/fisiologia , Adulto , Idoso , Algoritmos , Mapeamento Encefálico , Cadáver , Potenciais Evocados Visuais/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Modelos Estatísticos , Distribuição Normal , Estimulação Luminosa , Córtex Visual/anatomia & histologia
16.
Phys Med Biol ; 52(7): 1783-800, 2007 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-17374911

RESUMO

Standardized low-resolution brain electromagnetic tomography (sLORETA) is a widely used technique for source localization. However, this technique still has some limitations, especially under realistic noisy conditions and in the case of deep sources. To overcome these problems, we present here swLORETA, an improved version of sLORETA, obtained by incorporating a singular value decomposition-based lead field weighting. We show that the precision of the source localization can further be improved by a tomographic phase synchronization analysis based on swLORETA. The phase synchronization analysis turns out to be superior to a standard linear coherence analysis, since the latter cannot distinguish between real phase locking and signal mixing.


Assuntos
Encéfalo/patologia , Eletroencefalografia/métodos , Tomografia/métodos , Simulação por Computador , Eletroencefalografia/instrumentação , Fenômenos Eletromagnéticos , Humanos , Processamento de Imagem Assistida por Computador , Modelos Neurológicos , Modelos Estatísticos , Modelos Teóricos , Imagens de Fantasmas , Software , Fatores de Tempo , Tomografia/instrumentação
17.
J Biol Phys ; 32(3-4): 307-33, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19669469

RESUMO

Effective desynchronization can be exploited as a tool for probing the functional significance of synchronized neural activity underlying perceptual and cognitive processes or as a mild treatment for neurological disorders like Parkinson's disease. In this article we show that pulse-based desynchronization techniques, originally developed for networks of globally coupled oscillators (Kuramoto model), can be adapted to networks of coupled neurons with dendritic dynamics. Compared to the Kuramoto model, the dendritic dynamics significantly alters the response of the neuron to the stimulation. Under medium stimulation amplitude a bistability of the response of a single neuron is observed. When stimulated at some initial phases, the neuron displays only modulations of its firing, whereas at other initial phases it stops oscillating entirely. Significant alterations in the duration of stimulation-induced transients are also observed. These transients endure after the end of the stimulation and cause maximal desynchronization to occur not during the stimulation, but with some delay after the stimulation has been turned off. To account for this delayed desynchronization effect, we have designed a new calibration procedure for finding the stimulation parameters that result in optimal desynchronization. We have also developed a new desynchronization technique by low frequency entrainment. The stimulation techniques originally developed for the Kuramoto model, when using the new calibration procedure, can also be applied to networks with dendritic dynamics. However, the mechanism by which desynchronization is achieved is substantially different than for the network of Kuramoto oscillators. In particular, the addition of dendritic dynamics significantly changes the timing of the stimulation required to obtain desynchronization. We propose desynchronization stimulation for experimental analysis of synchronized neural processes and for the therapy of movement disorders.

18.
Am J Physiol Lung Cell Mol Physiol ; 289(3): L460-7, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15908475

RESUMO

Exposure to airborne particulates makes the detoxification of metals a continuous challenge for the lungs. Based on the fate of iron in airway epithelial cells, we postulated that divalent metal transporter-1 (DMT1) participates in detoxification of metal associated with air pollution particles. Homozygous Belgrade rats, which are functionally deficient in DMT1, exhibited diminished metal transport from the lower respiratory tract and greater lung injury than control littermates when exposed to oil fly ash. Preexposure of normal rats to iron in vivo increased expression of the isoform of DMT1 protein that lacked an iron-response element (-IRE), accelerated metal transport out of the lung, and decreased injury after particle exposure. In contrast, normal rats preexposed to vanadium showed less expression of the -IRE isoform of DMT1, decreased metal transport, and greater pulmonary injury after particle instillation. Respiratory epithelial cells in culture gave similar results. Also, DMT1 mRNA and protein expression for the -IRE isoform increased or decreased in these cells when exposed to iron or vanadium, respectively. These results thus demonstrate for the first time a primary role for DMT1 in lung metal transport and detoxification.


Assuntos
Proteínas de Transporte de Cátions/fisiologia , Proteínas de Ligação ao Ferro/fisiologia , Pneumopatias/induzido quimicamente , Pneumopatias/prevenção & controle , Metais , Animais , Transporte Biológico/efeitos dos fármacos , Western Blotting , Proteínas de Transporte de Cátions/deficiência , Proteínas de Transporte de Cátions/metabolismo , Linhagem Celular Transformada , Compostos Férricos/farmacologia , Imuno-Histoquímica , Ferro/farmacocinética , Proteínas de Ligação ao Ferro/metabolismo , Metais/metabolismo , Estresse Oxidativo , Isoformas de Proteínas/metabolismo , Compostos de Amônio Quaternário/farmacologia , Ratos , Ratos Endogâmicos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Vanádio/farmacocinética , Compostos de Vanádio/farmacologia
19.
Ann Surg ; 240(1): 51-6, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15213618

RESUMO

OBJECTIVE: To compare biliopancreatic diversion (BPD) without duodenal switch (DS) and with duodenal switch (BPDDS). BACKGROUND: A reduction of 70% of excess body weight can be achieved after BPD, but there is a risk of malnutrition and diarrhea. This risk may be reduced by pyloric preservation with BPDDS. METHODS: BPD was performed until 1999, when BPDDS was introduced, both with a common channel of 50 cm. At their latest clinic visit, patients filled in a questionnaire regarding weight loss, dietary history, gastrointestinal symptoms, obesity-related comorbidity, and medication including dietary supplements and underwent a serum nutritional screen. RESULTS: BPD was performed in 73 patients and BPDDS in 61 patients, with a median preoperative body mass index (BMI) of 44.8 kg/m and a median follow-up of 28 months. There were no significant differences between BPD and BPDDS with regards to age, sex, BMI, or morbidity. Median excess weight loss and BMI at 12, 24, and 36 months was 64.1, 71.0, and 72.1% and 33.1, 31.5, and 31.5 kg/m, respectively; there were no significant differences between BPD and BPDDS. There were no significant differences between BPD and BPDDS with regards to meal size, fat score, nausea, vomiting, diarrhea, or nutritional parameters. However, 18% of patients were hypoalbuminemic, 32% anemic, 25% hypocalcemic, and almost half had low vitamin A, D, and K levels, despite more than 80% taking vitamin supplementation. CONCLUSION: DS does not improve weight loss or lessen the gastrointestinal or nutritional side effects of BPD.


Assuntos
Desvio Biliopancreático/métodos , Duodeno/cirurgia , Estado Nutricional , Obesidade Mórbida/cirurgia , Adulto , Idoso , Desvio Biliopancreático/efeitos adversos , Índice de Massa Corporal , Diarreia/etiologia , Gorduras na Dieta/administração & dosagem , Suplementos Nutricionais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Náusea/etiologia , Vitaminas/administração & dosagem , Vômito/etiologia , Redução de Peso
20.
Obes Surg ; 14(2): 165-9, 2004 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15018743

RESUMO

BACKGROUND: Controversy exists regarding the best surgical treatment for superobesity (BMI >50 kg/m(2)), and a comparison of the 2 most commonly performed procedures in Europe, namely biliopancreatic diversion (BPD) and laparoscopic adjustable gastric banding (LAGB), has not yet been reported. METHODS: BPD has been performed in 134 morbidly obese patients since 1996, and as the primary bariatric procedure in 23 superobese patients. 23 sex-matched patients who most closely resembled the age and BMI of the 23 BPD patients were chosen from 1319 patients who had undergone LAGB since 1996. These groups were compared using appropriate statistical tests. RESULTS: BPD was performed laparoscopically in 12 patients. Median excess weight loss at 24 months was 64.4% following BPD and 48.4% following LAGB. Hospital stay and complication rate were significantly greater with BPD, although the majority of complications were related to the laparotomy wound in patients undergoing open BPD. Rate of resolution of obstructive sleep apnea, hypertension and diabetes mellitus following LAGB was similar to BPD. CONCLUSION: BPD results in significantly greater weight loss than LAGB in superobese patients, but is associated with a longer hospital stay and a higher complication rate in patients undergoing open BPD.


Assuntos
Desvio Biliopancreático , Gastroplastia , Laparoscopia , Obesidade Mórbida/cirurgia , Complicações Pós-Operatórias , Adulto , Idoso , Índice de Massa Corporal , Feminino , Seguimentos , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Fatores de Tempo , Resultado do Tratamento , Redução de Peso
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