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1.
Group Decis Negot ; 32(1): 147-176, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36258887

RESUMEN

In this paper, we apply the Analytic Hierarchy Process approach to conflict resolution in the context of the Russia-Ukraine conflict. We build models that illustrate the evaluation criteria, strategic and sub-criteria, and concessions for each party in this negotiation. Ratings are used to evaluate the degree to which concessions contribute or take away from successful resolution of the conflict. Afterwards, gain ratios are built to determine the benefit-cost scores so that concessions may be traded that result in equitable solutions. The approach presented here demonstrates for the first time why all concessions that parties to a conflict may offer might not trade all at once. A Max-Min optimization approach is used to maximize the gain to both parties of the conflict while minimizing the disparity in gain between the two.

2.
Am J Med Qual ; 34(3): 266-275, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30525894

RESUMEN

The current study evaluates changes in access as a result of the MyVA Access program-a system-wide effort to improve patient access in the Veterans Health Administration. Data on 20 different measures were collected, and changes were analyzed using t tests and Chow tests. Additionally, organizational health-how able a system is to create health care practice change-was evaluated for a sample of medical centers (n = 36) via phone interviews and surveys conducted with facility staff and technical assistance providers. An organizational health variable was created and correlated with the access measures. Results showed that, nationally, average wait times for urgent consults, new patient wait times for mental health and specialty care, and slot utilization for primary and specialty care patients improved. Patient satisfaction measures also improved, and patient complaints decreased. Better organizational health was associated with improvements in patient access.


Asunto(s)
Accesibilidad a los Servicios de Salud/organización & administración , Mejoramiento de la Calidad/organización & administración , United States Department of Veterans Affairs/organización & administración , Humanos , Innovación Organizacional , Satisfacción del Paciente/estadística & datos numéricos , Evaluación de Programas y Proyectos de Salud , Encuestas y Cuestionarios , Estados Unidos , Listas de Espera
3.
Med Decis Making ; 38(5): 601-613, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29611458

RESUMEN

BACKGROUND: Current colorectal cancer screening guidelines by the US Preventive Services Task Force endorse multiple options for average-risk patients and recommend that screening choices should be guided by individual patient preferences. Implementing these recommendations in practice is challenging because they depend on accurate and efficient elicitation and assessment of preferences from patients who are facing a novel task. OBJECTIVE: To present a methodology for analyzing the sensitivity and stability of a patient's preferences regarding colorectal cancer screening options and to provide a starting point for a personalized discussion between the patient and the health care provider about the selection of the appropriate screening option. METHODS: This research is a secondary analysis of patient preference data collected as part of a previous study. We propose new measures of preference sensitivity and stability that can be used to determine if additional information provided would result in a change to the initially most preferred colorectal cancer screening option. RESULTS: Illustrative results of applying the methodology to the preferences of 2 patients, of different ages, are provided. The results show that different combinations of screening options are viable for each patient and that the health care provider should emphasize different information during the medical decision-making process. CONCLUSION: Sensitivity and stability analysis can supply health care providers with key topics to focus on when communicating with a patient and the degree of emphasis to place on each of them to accomplish specific goals. The insights provided by the analysis can be used by health care providers to approach communication with patients in a more personalized way, by taking into consideration patients' preferences before adding their own expertise to the discussion.


Asunto(s)
Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/psicología , Detección Precoz del Cáncer/psicología , Conocimientos, Actitudes y Práctica en Salud , Prioridad del Paciente/psicología , Relaciones Médico-Paciente , Anciano , Anciano de 80 o más Años , Toma de Decisiones , Detección Precoz del Cáncer/métodos , Femenino , Humanos , Masculino , Guías de Práctica Clínica como Asunto , Medicina de Precisión , Sensibilidad y Especificidad , Estados Unidos
4.
J Refract Surg ; 34(3): 164-170, 2018 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-29522225

RESUMEN

PURPOSE: To assess the clinically acceptable range of inlay decentration with respect to the light-constricted pupil center and the coaxially sighted corneal light reflex (CSCLR) for an inlay (Raindrop Near Vision Inlay; ReVision Optics, Inc., Lake Forest, CA) that reshapes the anterior corneal surface. METHODS: In this retrospective, observational cohort study of 115 patients with emmetropic or low hyperopic presbyopia who were implanted with a shape-changing corneal inlay, visual acuity, task performance (in good and dim light), reports of halos and glare, and satisfaction data were collected from the preoperative and 3-month postoperative examinations. Inlay centration with respect to the pupil center and CSCLR was determined from the center of the inlay effect derived from iTrace (Tracey Technologies, Houston, TX) wavefront measurements. Multivariate regression models assessed the influence of inlay position on visual outcomes. RESULTS: On average, monocular uncorrected near visual acuity (UNVA) improved 4.9 ± 1.7 lines in the treated eye, with no loss in binocular distance vision. Eighty-three percent of implants were centered radially within 0.5 mm of the pupil center. Multivariate analysis of decentration with respect to both the pupil center and CSCLR revealed no significant interaction with the above clinical outcomes, with the exception of UNVA in the treated eye (all P > .05, α = 0.05). For decentration of less than 0.75 mm, the change in UNVA was less than 1 line. CONCLUSIONS: Distance and near visual acuity, task performance, severity of halos and glare, and satisfaction were independent of radial decentration of the Raindrop Near Vision Inlay of less than 0.75 mm from the light-constricted pupil. [J Refract Surg. 2018;34(3):164-170.].


Asunto(s)
Sustancia Propia/cirugía , Hiperopía/cirugía , Luz , Presbiopía/cirugía , Prótesis e Implantes , Implantación de Prótesis , Pupila/efectos de la radiación , Adulto , Parpadeo/fisiología , Femenino , Deslumbramiento , Humanos , Hiperopía/fisiopatología , Masculino , Persona de Mediana Edad , Satisfacción del Paciente , Presbiopía/fisiopatología , Estudios Retrospectivos , Colgajos Quirúrgicos , Encuestas y Cuestionarios , Visión Binocular/fisiología , Agudeza Visual/fisiología
5.
J Cataract Refract Surg ; 43(11): 1443-1449, 2017 11.
Artículo en Inglés | MEDLINE | ID: mdl-29223234

RESUMEN

PURPOSE: To compare the induced addition (add)-power profile and epithelial remodeling between patients receiving hyperopic and myopic laser in situ keratomileusis (LASIK) concurrently with implantation of a corneal shape-changing inlay. SETTING: Specialty clinics in Monterrey and Tijuana, Mexico. DESIGN: Retrospective case series. METHODS: Preoperative hyperopic patients (mean spherical equivalent [SE] treatment +1.71 diopters [D] ± 0.51 [SD]) and myopic patients (mean SE treatment -2.48 ± 1.33 D) had implantation of a Raindrop Near Vision Inlay in the nondominant eye immediately after the excimer laser ablation in both eyes under a corneal flap. Monocular and binocular visual acuities were recorded at 6 m. Wavefront measurement analysis yielded the mean inlay add-power profile, and optical coherence tomography images yielded the mean epithelial remodeling profile. RESULTS: In the inlay eye in the hyperopic group (n = 34) and myopic group (n = 29), the mean uncorrected near visual acuity exceeded 20/25 (85% 20/25 or better), the mean uncorrected distance visual acuity (UDVA) was 20/32 (62% 20/32 or better), and the mean binocular UDVA was 20/18 (100% 20/25 or better). The add-power profiles for the hyperopic and myopic groups were similar. The epithelial thinning profiles were also the same, thinning centrally by approximately 19 µm, and were uncorrelated with the treated refractive error. CONCLUSIONS: After concurrent LASIK and inlay implantation, the visual acuity, induced add-power profile, and epithelial remodeling were the same, regardless of hyperopic or myopic treatment.


Asunto(s)
Hiperopía , Queratomileusis por Láser In Situ , Miopía , Córnea/cirugía , Humanos , Hiperopía/cirugía , Láseres de Excímeros , Miopía/cirugía , Errores de Refracción , Colgajos Quirúrgicos , Agudeza Visual
6.
Mol Genet Genomic Med ; 1(2): 108-112, 2013 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-23957016

RESUMEN

Epidermolytic ichthyosis (EI) is a rare skin disorder characterized by generalized erythroderma and cutaneous blistering at birth, which is substituted by hyperkeratosis later in life. It is caused by autosomal dominant mutations in highly conserved regions of KRT1 and KRT10. To date, only 4 mutations with autosomal recessive inheritance of EI have been described in consanguineous families. All of them affect the 2B domain of KRT10. In the present study we describe four patients with EI (including one lethal case) born from unaffected parents in a consanguineous family of a native Venezuelan community. The objective of this study was to characterize the clinical, genetic and morphological aspects of the disease in this family, as well as understand its functional implications. Genomic DNA was sequenced for KRT10 and KRT1. Immunofluoresence for keratin expression was performed on cutaneous biopsies. After examination of cutaneous biopsies histology, our results showed hyperkeratosis and acantholysis with an expanded granular layer. Sequencing of KRT10 demonstrated a non-sense mutation (p.Tyr282Ter.) corresponding to the 1B domain of the protein in patients and a heterozygous pattern in other family members, resulting in complete absence of K10. The loss of K10 was compensated by upregulation of K14 and K17. In conclusion, this novel mutation in KRT10 is the first recessive genetic variation that is not located in the so called "hot spot" for recessive EI, suggesting that other areas of the gene are also susceptible for such mutations.

7.
Health Care Manag Sci ; 16(2): 119-28, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23132123

RESUMEN

Highly imbalanced data sets are those where the class of interest is rare. In this paper, we compare the performance of several common data mining methods, logistic regression, discriminant analysis, Classification and Regression Tree (CART) models, C5, and Support Vector Machines (SVM) in predicting the discharge status (alive or deceased, with "deceased" being the class of interest) of patients from an Intensive Care Unit (ICU). Using a variety of misclassification cost ratio (MCR) values and using specificity, recall, precision, the F-measure, and confusion entropy (CEN) as criteria for evaluating each method's performance, C5 and SVM performed better than the other methods. At a MCR of 100, C5 had the highest recall and SVM the highest specificity and lowest CEN. We also used Hand's measure to compare the five methods. According to Hand's measure, logistic regression performed the best. This article makes several contributions. We show how the use of MCR for analyzing imbalanced medical data significantly improves the method's classification performance. We also found that the F-measure and precision did not improve as the MCR was increased.


Asunto(s)
Recolección de Datos/métodos , Minería de Datos/métodos , Unidades de Cuidados Intensivos/estadística & datos numéricos , Modelos Estadísticos , Alta del Paciente/estadística & datos numéricos , Árboles de Decisión , Análisis Discriminante , Femenino , Mortalidad Hospitalaria , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Máquina de Vectores de Soporte , Estados Unidos
8.
Surg Infect (Larchmt) ; 13(3): 141-6, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22568920

RESUMEN

BACKGROUND: There has not been an appraisal of outcomes of appendectomy for more than 10 years. More reliable diagnostic techniques and minimally invasive surgery are now in widespread use, yet the impact of these advances remains unknown. METHODS: A retrospective review was performed of 453 patients who underwent appendectomy for appendicitis at a single hospital from 2004 to 2009. Patient demographics, operative characteristics, procedure cost, and pathologic diagnoses were analyzed. RESULTS: The overall rate of complicated appendicitis was 13%, with a negative appendectomy rate of 4.9%. The average age was significantly greater for patients with complicated versus uncomplicated appendicitis (47 vs. 33 years, respectively; p<0.001), and by logistic regression, age (as a continuous variable) was a significant factor for complicated appendicitis (p<0.001). The hospital length of stay was 2.3 times longer for patients with complicated appendicitis (4.4 vs. 1.9 days; p<0.001), and the average cost was 86% higher ($14,125 vs. $7,595; p<0.001), the difference in cost being attributable mostly to pharmacy and nursing costs. CONCLUSIONS: Advances in diagnostic and surgical technique may be altering traditionally accepted rates of complicated appendicitis and negative appendectomy. For the first time, age is shown to be related to the rate of complicated appendicitis as a continuous variable rather than simply an extreme. Patients with complicated appendicitis still stay in the hospital longer, and there is a large cost difference as a result.


Asunto(s)
Apendicectomía/economía , Apendicitis/cirugía , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Análisis de Varianza , Apendicitis/complicaciones , Apendicitis/economía , Femenino , Costos de Hospital , Humanos , Tiempo de Internación/economía , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del Tratamiento , Adulto Joven
9.
Surgery ; 150(2): 299-305, 2011 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21801967

RESUMEN

BACKGROUND: Financial pressures drive efforts to optimize hospital resource use, but inefficiencies occur in systems as volume nears total capacity. We examined how operating room use impacts efficiency and costs of treating an urgent surgical condition. METHODS: A retrospective review of patients who underwent appendectomy for appendicitis at a single hospital from 2004 to 2009 was performed. Patient demographics, operative characteristics, pathologic diagnoses, hospital time intervals, and costs were analyzed. Gap time (time from case booking to surgery start) was used to measure operating room availability. RESULTS: In all, 453 patients met inclusion criteria. Longer gap times were associated with increased hospital-based costs. A gap time of greater than 2 h was associated with 39% higher costs to the hospital, which could not be accounted for by any single cost center. The patients in the 2 groups had similar medical and surgical complexity, as well as similar clinical outcomes and hospital duration of stay. Gap times were greatest during peak elective operating room activity (7 am to 11 pm); however, the total hospital costs were not related to the time of day of the case. CONCLUSION: A short delay in operating room availability for urgent cases is associated with significantly increased total hospital costs. Our data suggest this finding is attributable to inefficient care when the operating room volume nears total capacity.


Asunto(s)
Apendicectomía/economía , Apendicitis/cirugía , Eficiencia Organizacional/economía , Accesibilidad a los Servicios de Salud/economía , Costos de Hospital , Quirófanos/economía , Adulto , Humanos , Persona de Mediana Edad , Estudios Retrospectivos , Factores de Tiempo , Adulto Joven
10.
Anesthesiology ; 109(3): 408-16, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18719438

RESUMEN

BACKGROUND: Surgical scheduling is complicated by both naturally occurring and human-induced variability in the demand for surgical services. Surgical demand time series are decomposed into periodic, lagged, and linear trends with frequent occurrences of nonconstant variations in mean and variance. The authors used time series methods to model surgical demand time series in order to improve the scheduling of scarce surgical resources. METHODS: With institutional approval, the authors studied 47,752 surgeries undertaken at a large academic medical center. They initially extracted periodic information from the time series using two frequency domain techniques: the harmonic F test and the multitaper test. They subsequently extracted lagged (correlated) behavior using a seasonal autoregressive integrated moving average model. Finally, they used moving variance filters on the residuals to identify variance in the time series that coincided with major US holidays. RESULTS: Linear terms such as periodic cycles, trends, and daily and weekly lags explained 80% of the variance in the raw time series. In the residuals, the authors used moving variance filters to detect nonlinear variance artifacts that correlated with surgical activities on specific US holidays. CONCLUSIONS: After extracting linear terms, the remaining variance was attributable to a combination of nonlinear and unexplained random events. The authors used the term holiday variance to describe a specific nonlinear disturbance in surgical demand attributable to statutory US holidays. Resolving these holiday variances may assist in management and scheduling of scarce surgical personnel and resources.


Asunto(s)
Vacaciones y Feriados/estadística & datos numéricos , Periodicidad , Admisión y Programación de Personal/estadística & datos numéricos , Servicio de Cirugía en Hospital/estadística & datos numéricos , Procedimientos Quirúrgicos Operativos/estadística & datos numéricos , Centros Médicos Académicos/organización & administración , Centros Médicos Académicos/estadística & datos numéricos , Necesidades y Demandas de Servicios de Salud , Humanos , Estados Unidos , Recursos Humanos
11.
Rev Sci Instrum ; 78(8): 085106, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17764354

RESUMEN

A moving bed scale reactor setup for studying complex gas-solid reactions has been designed in order to obtain kinetic data for scale-up purpose. In this bench scale reactor setup, gas and solid reactants can be contacted in a cocurrent and countercurrent manner at high temperatures. Gas and solid sampling can be performed through the reactor bed with their composition profiles determined at steady state. The reactor setup can be used to evaluate and corroborate model parameters accounting for intrinsic reaction rates in both simple and complex gas-solid reaction systems. The moving bed design allows experimentation over a variety of gas and solid compositions in a single experiment unlike differential bed reactors where the gas composition is usually fixed. The data obtained from the reactor can also be used for direct scale-up of designs for moving bed reactors.


Asunto(s)
Técnicas de Química Analítica/instrumentación , Análisis de Inyección de Flujo/instrumentación , Gases/química , Microfluídica/instrumentación , Robótica/instrumentación , Manejo de Especímenes/instrumentación , Técnicas de Química Analítica/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Análisis de Inyección de Flujo/métodos , Microfluídica/métodos , Movimiento (Física) , Reproducibilidad de los Resultados , Robótica/métodos , Sensibilidad y Especificidad , Manejo de Especímenes/métodos
12.
J Cataract Refract Surg ; 33(1): 37-46, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17189791

RESUMEN

PURPOSE: To describe a dual-optic accommodating intraocular lens (IOL) based on theoretical considerations. SETTING: University and independent research group. METHODS: Ray-tracing analysis using optical modeling software (ZEMAXTM, Focus Software Inc., Tucson, Ariz) in a theoretical model eye was used to analyze lens configurations to optimize the accommodative and magnification effects of axial lens displacement. Finite-element modelling using a commercially available PC-based software package (COSMOS DesignSTAR) was applied to design the biomechanical parameters of the inter-optic articulations and optics. RESULTS: Ray-tracing analysis indicated that a dual-optic design with a high plus-powered front optic coupled to a minus posterior optic produced greater change in conjugation power of the eye compared to a single-optic intraocular lens and that magnification effects were unlikely to account for improved near vision. Finite-element modelling indicated that the 2 optics can be linked by spring-loaded haptics that allow anterior and posterior axial displacement of the front optic in response to changes in ciliary body tone and capsular tension. CONCLUSION: A dual-optic design linked by spring haptics increases the accommodative effect of axial optic displacement with minimal magnification effect and has promise for improving the performance of accommodative intraocular lenses.


Asunto(s)
Acomodación Ocular/fisiología , Lentes Intraoculares , Modelos Teóricos , Óptica y Fotónica , Fenómenos Biomecánicos , Extracción de Catarata , Simulación por Computador , Humanos , Implantación de Lentes Intraoculares , Matemática , Diseño de Prótesis , Refracción Ocular/fisiología
13.
J Cataract Refract Surg ; 33(1): 47-52, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17189792

RESUMEN

PURPOSE: To evaluate the clinical outcomes of an accommodating dual-optic intraocular lens (IOL). SETTING: Private practice and university centers. METHODS: A prospective noncomparative case series with retrospective control comprised 21 patients (26 eyes) scheduled for small-incision extracapsular cataract extraction by phacoemulsification with implantation of the Synchrony dual-optic accommodating IOL (Visiogen) (accommodating IOL group) and 10 patients who had small-incision extracapsular phacoemulsification with implantation of a monofocal, single-optic IOL at least 6 months previously (control group). Patients were examined 1, 3, 6, and 12 months after surgery. Defocus curves in the accommodating IOL group were compared with those in the control group. The main outcome measures were postoperative distance uncorrected and best corrected visual acuity; near uncorrected, distance corrected, and near corrected visual acuity; and accommodative range based on defocus curves. RESULTS: Twenty-four eyes were available at the 6-month follow-up visit. All eyes had best corrected distance visual acuity of 20/40 or better, and 19 eyes (79%) had an uncorrected distance visual acuity of 20/40 or better. Uncorrected near visual acuity was 20/40 or better in all eyes. With distance correction, 23 eyes (96%) had an acuity of 20/40 or better at near. Defocus curve analysis suggested a mean accommodative range of 3.22 diopters (D) +/- 0.88 (SD) (range 1.00 to 5.00 D) in the accommodating IOL group and 1.65 +/- 0.58 D in the control group (range 1.00 to 2.50 D) (P<.05). CONCLUSION: The Synchrony dual-optic IOL shows promise as an option to provide accommodative function in pseudophakic patients.


Asunto(s)
Acomodación Ocular/fisiología , Implantación de Lentes Intraoculares , Lentes Intraoculares , Facoemulsificación , Seudofaquia/fisiopatología , Adulto , Anciano , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Estudios Prospectivos , Diseño de Prótesis , Refracción Ocular/fisiología , Estudios Retrospectivos , Agudeza Visual/fisiología
14.
J Cataract Refract Surg ; 32(4): 655-61, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16698490

RESUMEN

PURPOSE: To evaluate and compare the incidence of capsular bag opacification, particularly interlenticular opacification (ILO), in rabbit eyes implanted with a dual-optic silicone intraocular lens (IOL) or piggyback lenses. SETTING: John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Ten dual-optic study IOLs (Synchrony), 10 control pairs of piggyback silicone-plate lenses, and 10 control pairs of piggyback single-piece hydrophobic acrylic lenses were implanted in the capsular bag of 30 rabbit eyes following phacoemulsification. After a 6-week follow-up, the rabbits were killed and their eyes enucleated. Anterior capsule opacification and posterior capsule opacification were graded on a 0 to 4 scale from a posterior or Miyake-Apple view. Interlenticular opacification was noted in relation to the center of the interlenticular space (periphery, paracentral, and central area) and to the number of quadrants involved. The eyes were then evaluated histopathologically. RESULTS: Postoperative inflammatory reaction was similar in all groups. Interlenticular opacification formation was statistically different among the 3 groups of lenses (ILO extension, P = .0013, and ILO extension x ILO quadrants, P = .0023; Kruskal-Wallis test). Pairwise post comparisons of ILO formation showed that the differences between the study IOL group and the silicone-plate lens group were not significant. Interlenticular opacification post comparisons between the hydrophobic acrylic lenses and the study lens or the silicone-plate lenses were significant (P = .002 and P = .001, respectively). Histopathologic examination showed extension of the proliferating cortical material from the peripheral Soemmering's ring into the interlenticular space, causing ILO, especially with the pairs of hydrophobic acrylic lenses. CONCLUSIONS: In this rabbit model, ILO was significantly associated with pairs of hydrophobic acrylic lenses implanted in the bag. This study appears to confirm clinical observations that implantation of 2 silicone-plate lenses in the bag is not associated with ILO. There was also a relative lack of ILO with the dual-optic silicone lens.


Asunto(s)
Catarata/etiología , Cápsula del Cristalino/patología , Implantación de Lentes Intraoculares/métodos , Lentes Intraoculares , Complicaciones Posoperatorias , Elastómeros de Silicona , Animales , Incidencia , Conejos
15.
J Cataract Refract Surg ; 31(2): 363-8, 2005 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15767160

RESUMEN

PURPOSE: To assess the correlation between continuous curvilinear capsulorhexis (CCC) size and visual outcomes in patients with an accommodating intraocular lens (IOL). SETTING: Heidelberg IOL and Refractive Surgery Research Group, Department of Ophthalmology, Ruprecht-Karls-University of Heidelberg, Heidelberg, Germany. METHODS: Nineteen eyes had phacoemulsification and implantation of a 1CU accommodating IOL (HumanOptics AG). Three months after surgery, the uncorrected and best corrected distance and near visual acuities and the distance corrected near visual acuity were measured. Retroillumination photographs were taken to assess CCC size and centration and the amount of overlap between the CCC and IOL optic. The photographs were analyzed using Evaluation of Posterior Capsule Opacification system software. RESULTS: The mean age of the patients was 53.5 years (range 30 to 73 years). The mean uncorrected distance acuity improved from 0.05 preoperatively to 0.70 at 3 months and the best corrected near acuity, from 0.30 to 0.94. The mean postoperative distance corrected near acuity was 0.5 (range 0.1 to 1.0), which improved to 0.9 with near correction. The mean CCC size (4.3 mm) and amount of CCC decentration (0.35 mm) did not correlate with visual outcomes. However, there was a correlation between the amount of CCC-optic overlap (mean 35%; range 16% to 55%) and distance corrected near acuity (r = 0.641, P = .003). Distance corrected near acuity was better with less overlapping; that is, with a larger CCC. CONCLUSIONS: A larger capsulorhexis with less CCC-optic overlapping gave better near visual outcomes. Results indicate that an overlap between 25% and 35%, which correlates with a CCC between 4.5 mm and 5.0 mm, provides the best capsule strength without compromising accommodation with the single-piece 1CU IOL.


Asunto(s)
Acomodación Ocular/fisiología , Capsulorrexis/métodos , Lentes Intraoculares , Facoemulsificación/métodos , Adulto , Anciano , Humanos , Implantación de Lentes Intraoculares , Persona de Mediana Edad , Diseño de Prótesis , Agudeza Visual/fisiología
16.
Clin Invest Med ; 28(6): 364-7, 2005 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-16450636

RESUMEN

This research describes a constraint-based heuristic model of capacity segmentation for outpatient facilities used to estimate the effect of segmentation constraints on stakeholders. Growth of free-standing ambulatory surgery centres has been dramatic in recent years with institutions being urged by governments and insurers to segment inpatients (IP) and outpatients (OP) to reduce costs and improve services. Critics of segmentation argue it is a false economy to separate inpatients and outpatients since pooling of patients in large IP facilities offers economies of scale and opportunities for parallel processing, not to mention elimination of infrastructure. We implemented a constraint-based heuristic model of capacity segmentation for OP facilities and used it to estimate the effect of segmentation on stakeholders.


Asunto(s)
Citas y Horarios , Servicio Ambulatorio en Hospital/economía , Garantía de la Calidad de Atención de Salud/economía , Cirugía General , Costos de la Atención en Salud , Humanos , Modelos Organizacionales , Servicio Ambulatorio en Hospital/organización & administración , Servicio Ambulatorio en Hospital/estadística & datos numéricos
17.
J Cataract Refract Surg ; 30(6): 1356-61, 2004 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-15177617

RESUMEN

A 74-year-old woman had uneventful phacoemulsification with implantation of a single-piece hydrophobic acrylic intraocular lens (IOL) (SA30AL) in her left eye. Two weeks after the surgery, the patient presented for ophthalmological consultation reporting pseudophakic dysphotopsia, which she had subjectively noted since surgery. Explantation/exchange of the IOL was performed 3 months after the surgery. The IOL was strongly attached to the capsule, which was fibrotic and contracted; explantation of the capsular bag complex in toto was done. To our knowledge, this is the first case of explantation of this IOL design with clinicopathological correlation.


Asunto(s)
Remoción de Dispositivos , Lentes Intraoculares , Polihidroxietil Metacrilato , Seudofaquia/cirugía , Trastornos de la Visión/cirugía , Anciano , Femenino , Fibrosis , Humanos , Cápsula del Cristalino/patología , Implantación de Lentes Intraoculares , Facoemulsificación , Diseño de Prótesis , Seudofaquia/patología , Reoperación , Trastornos de la Visión/patología
18.
J Cataract Refract Surg ; 30(5): 1114-23, 2004 May.
Artículo en Inglés | MEDLINE | ID: mdl-15130653

RESUMEN

PURPOSE: To evaluate the development of capsular bag opacification in rabbit eyes after implantation of an intraocular lens (IOL) designed to minimize contact between the anterior capsule and the IOL and ensure expansion of the capsular bag. SETTING: David J. Apple, MD Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Ten New Zealand white rabbits had a study IOL (new accommodating silicone IOL [Synchrony, Visiogen, Inc.]) implanted in 1 eye and a control IOL (1-piece plate silicone IOL with large fixation holes) implanted in the other eye. Intraocular lens position, anterior capsule opacification (ACO), and posterior capsule opacification (PCO) were qualitatively assessed using slitlamp retroillumination photographs of the dilated eyes. Anterior capsule opacification and PCO were graded on a 0 to 4 scale after the eyes were enucleated (Miyake-Apple posterior and anterior views after excision of the cornea and iris). The eyes were also evaluated histopathologically. RESULTS: The rate of ACO and PCO was significantly higher in the control group. Fibrosis and ACO were almost absent in the study group; the control group exhibited extensive capsulorhexis contraction, including capsulorhexis occlusion. Postoperative IOL dislocation into the anterior chamber and pupillary block syndrome were observed in some eyes in the study group. CONCLUSIONS: The special design features associated with the study IOL appeared to help prevent PCO. Complications in the study group were probably caused by the increased posterior vitreous pressure in rabbit eyes compared to human eyes and the relatively large size of the study IOL relative to the anterior segment of rabbit eyes.


Asunto(s)
Catarata/prevención & control , Cápsula del Cristalino/patología , Implantación de Lentes Intraoculares/métodos , Lentes Intraoculares , Complicaciones Posoperatorias/prevención & control , Animales , Materiales Biocompatibles , Capsulorrexis , Catarata/diagnóstico , Fibrosis , Modelos Animales , Complicaciones Posoperatorias/diagnóstico , Diseño de Prótesis , Conejos , Elastómeros de Silicona
19.
Health Care Manag Sci ; 7(2): 97-104, 2004 May.
Artículo en Inglés | MEDLINE | ID: mdl-15152974

RESUMEN

We present an empirical study of methods for estimating the location parameter of the lognormal distribution. Our results identify the best order statistic to use, and indicate that using the best order statistic instead of the median may lead to less frequent incorrect rejection of the lognormal model, more accurate critical value estimates, and higher goodness-of-fit. Using simulation data, we constructed and compared two models for identifying the best order statistic, one based on conventional nonlinear regression and the other using a data mining/machine learning technique. Better surgical procedure time estimates may lead to improved surgical operations.


Asunto(s)
Modelos Estadísticos , Procedimientos Quirúrgicos Operativos , Factores de Tiempo , Humanos
20.
J Cataract Refract Surg ; 30(3): 726-9, 2004 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15050277

RESUMEN

We present a 76-year-old patient who had ocular trauma with dehiscence of the wound and scleral rupture with a prolapsed iris, ciliary body, intraocular lens, and vitreous after uneventful cataract surgery with a self-sealing sclerocorneal tunnel incision. General anesthesia was not possible because the patient had a history of lung cancer with extensive emphysema and unstable coronary disease. Local retrobulbar or peribulbar anesthesia was not considered because of the risk for further extrusion of intraocular contents. Topical anesthesia was applied with a 10.0 mm x 2.5 mm cellulose sponge soaked in oxybuprocaine 0.4% (Novesine) placed under the upper and lower lid for 20 minutes. Surgical repair of a 14.0 mm scleral wound was achieved without complication or pain during the procedure.


Asunto(s)
Accidentes por Caídas , Anestesia Local/métodos , Lesiones Oculares Penetrantes/cirugía , Procaína/análogos & derivados , Esclerótica/lesiones , Dehiscencia de la Herida Operatoria/cirugía , Enfermedades de la Úvea/cirugía , Anciano , Anestésicos Locales/administración & dosificación , Lesiones Oculares Penetrantes/diagnóstico por imagen , Lesiones Oculares Penetrantes/etiología , Femenino , Migración de Cuerpo Extraño/diagnóstico por imagen , Migración de Cuerpo Extraño/etiología , Migración de Cuerpo Extraño/cirugía , Humanos , Lentes Intraoculares , Neoplasias Pulmonares/complicaciones , Neoplasias Pulmonares/diagnóstico por imagen , Procaína/administración & dosificación , Prolapso , Rotura , Dehiscencia de la Herida Operatoria/diagnóstico por imagen , Dehiscencia de la Herida Operatoria/etiología , Tomografía Computarizada por Rayos X , Enfermedades de la Úvea/diagnóstico por imagen , Enfermedades de la Úvea/etiología
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