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Surgical navigation has been shown to improve the accuracy of bone preparation and limb alignment in total knee arthroplasty (TKA). Previous work has shown the effectiveness of various types of navigation systems. Here, for the first time, we assessed the accuracy of a novel imageless semiautonomous handheld robotic sculpting system in performing bone resection and preparation in TKA using cadaveric specimens. In this study, we compared the planned and final implant placement in 18 cadaveric specimens undergoing TKA using the new tool. Eight surgeons carried out the procedures using three types of implant designs. A quantitative analysis was performed to determine the translational, angular, and rotational differences between the planned and achieved positions of the implants. The mean femoral flexion, varus/valgus, and rotational error was -2.0°, -0.1°, and -0.5°, respectively. The mean tibial posterior slope, and varus/valgus error was -0.2°, and -0.2°, respectively. We obtained higher flexion errors for the femoral implant when using cut-guides as compared to using a bur for cutting the bones. The image-free robotic sculpting tool achieved accurate implementation of the surgical plan with small errors in implant placement. Future studies will focus on determining how well the accurate implant placement translates into a clinical and functional benefit for the patient.
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Artroplastia de Reemplazo de Rodilla/instrumentación , Articulación de la Rodilla/cirugía , Procedimientos Quirúrgicos Robotizados/instrumentación , Artroplastia de Reemplazo de Rodilla/efectos adversos , Desviación Ósea/etiología , Desviación Ósea/prevención & control , Cadáver , Computadoras de Mano , Humanos , Prótesis de la Rodilla , Reproducibilidad de los Resultados , Procedimientos Quirúrgicos Robotizados/efectos adversosRESUMEN
Unicondylar Knee Arthroplasty (UKA) is a minimally-invasive surgical procedure for treating isolated compartmental knee osteoarthritis. Accurate implant placement is crucial for a successful UKA procedure. Previous work has shown the improvement in UKA by using robotic systems. Here, we present the implant alignment accuracy of a hand-held robotic UKA system compared with a conventional manual UKA system for 12 cadaver specimens. Two surgeons carried out equal number of medial UKAs with robotic UKA on one knee and the manual UKA on the other knee. Preoperative and postoperative computed tomography (CT) scans were obtained for each cadaveric model. The final implant positions were identified in the postoperative CT scan. The implant orientations were compared with the planned implant positions to obtain femoral and tibial implant alignment errors. Our results show that the femoral flexion, varus, and rotation root mean square errors for the robotic and conventional approach were 1.23°, 2.81°, 1.62° and 7.52°, 6.25°, 5.0°, respectively. The tibial slope and varus errors for the robotic and conventional approaches were 2.41°, 2.96° and 4.06°, 1.8°, respectively. We did not find any statistical significant difference (p = .05) in the performance of the two surgeons. We conclude that the hand-held robotic UKA system offers significant improvement in the final implant placement.
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Artroplastia de Reemplazo de Rodilla/instrumentación , Articulación de la Rodilla/cirugía , Osteoartritis de la Rodilla/cirugía , Procedimientos Quirúrgicos Robotizados/instrumentación , Artroplastia de Reemplazo de Rodilla/efectos adversos , Artroplastia de Reemplazo de Rodilla/métodos , Desviación Ósea/etiología , Desviación Ósea/prevención & control , Cadáver , Computadoras de Mano , Humanos , Prótesis de la Rodilla , Procedimientos Quirúrgicos Mínimamente Invasivos , Orientación Espacial , Reproducibilidad de los Resultados , Procedimientos Quirúrgicos Robotizados/efectos adversos , Procedimientos Quirúrgicos Robotizados/métodosRESUMEN
OBJECTIVE: Pretensioning is usually done using two methods - manual cyclical loading and using tensioner with a tendon board. Both the methods are being used with little knowledge about the superiority of either method. This study was done with the objective of trying to find out the better method. METHODS: A total of 50 patients were selected for the above mentioned study who were randomised into each of the two groups using chit system - In group A patients, cyclical loading was done by twenty times full flexion -extension movements but in group B patients, the graft was placed on a tensioner with 15 pounds tension for 10 minutes. All patients were operated by the same surgeon. The patients were put on a strict rehabilitation protocol. Patients were allowed to bear weight as tolerated. Patients returned for follow up at 6 weeks, 3 months, 6 months and 12 months. At each visit patients were followed with Lysholm's Score and ROLIMETER reading. RESULTS: The ROLIMETER reading and Lysholm's score were seen to improve from preoperative to postoperative period and improved further over time with the progress of the rehabilitation protocol in both the groups. When compared to each other Group A i.e. patients pretensioned with cyclical loading had better Lysholm scores and ROLIMETER readings with the difference being statistically significant at all time periods except at 1 year when the difference between the ROLIMETER readings in the two groups were no more significant, though the difference of the Lysholms score was still found to be statistically significant. CONCLUSION: It was concluded in this study that cyclical loading is a better method of pretensioning in ACL reconstruction than tensioner on tendon board with 15 pounds of tension for 10 minutes.
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After a knee replacement procedure, postoperative radiological assessment is carried out to evaluate outcome and predict procedure success. For this assessment, long-standing load-bearing antero-posterior radiographs are used to carry out manual identification of anatomic landmarks. These landmarks are subsequently used to estimate leg alignment. The positions of the landmarks in the radiographs are affected by the patient pose and the X-ray projection center. Although there is some past work exploring the impact of patient pose on the landmarks in the radiographs, there is no previous work on the impact of the X-ray projection center on the estimated leg alignment. In this work, we carried out a study of the impact of patient foot rotation, and X-ray projection center on landmark measurement errors, and estimation of leg alignment. In this evaluation, landmarks were first identified in three-dimensional computed tomography scans. Digitally reconstructed radiographs were then obtained from these scans under varying rotation and projection centers. Subsequently, landmarks were manually identified in these radiographs and leg alignment was estimated from these landmarks. We found that foot rotation leads to increased errors in certain landmarks. We also found that variations in the X-ray projection center do not lead to significant (p<0.01) errors in landmark measurements. Also, errors as large as 13.1 mm for the femoral knee center and 13.6 mm for the lateral malleolus led to a maximum error of 1.46° for the femoral mechanical axis and 0.66° for the tibial mechanical axis.
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Puntos Anatómicos de Referencia/fisiología , Artroplastia de Reemplazo de Rodilla/métodos , Fémur/cirugía , Pie/fisiología , Articulación de la Rodilla/cirugía , Tibia/fisiología , Soporte de Peso/fisiología , Fémur/fisiopatología , Humanos , Articulación de la Rodilla/fisiopatología , Rotación , Tomografía Computarizada por Rayos XRESUMEN
Unicondylar Knee Replacement (UKR) is an orthopedic surgical procedure to reduce pain and improve function in the knee. Load-bearing long-standing antero-posterior (AP) radiographs are typically used postoperatively to measure the leg alignment and assess the varus/valgus implant orientation. However, implant out-of-plane rotations, user variability, and X-ray acquisition parameters introduce errors in the estimation of the implant varus/valgus estimation. Previous work has explored the accuracy of various imaging modalities in this estimation. In this work, we explored the impact of out-of-plane rotations and X-ray acquisition parameters on the estimation of implant component varus/valgus angles. For our study, we used a single CT scan and positioned femoral and tibial implants under varying orientations within the CT volume. Then, a custom software application was used to obtain digitally reconstructed radiographs from the CT scan with implants under varying orientations. Two users were then asked to manually estimate the varus/valgus angles for the implants. We found that there was significant inter-user variability (p < 0.05) in the varus/valgus estimates for the two users. However, the 'ideal' measurements, obtained using actual implant orientations, showed small errors due to variations in implant orientation. We also found that variation in the projection center does not have a statistically significant impact (p < 0.01) on the estimation of implant varus/valgus angles. We conclude that manual estimates of UKR implant varus/valgus orientations are unreliable.
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Artroplastia de Reemplazo de Rodilla/métodos , Articulación de la Rodilla/diagnóstico por imagen , Articulación de la Rodilla/fisiopatología , Articulación de la Rodilla/cirugía , Prótesis de la Rodilla , Tomografía Computarizada por Rayos X , Fenómenos Biomecánicos , Humanos , Interpretación de Imagen Radiográfica Asistida por Computador , Programas Informáticos , Soporte de PesoRESUMEN
BACKGROUND: Although best practices have been developed for achieving door-to-needle (DTN) times ≤60 minutes for stroke thrombolysis, critical DTN process failures persist. We sought to compare these failures in the Emergency Department at an academic medical center and a community hospital. METHODS AND RESULTS: Failure modes effects and criticality analysis was used to identify system and process failures. Multidisciplinary teams involved in DTN care participated in moderated sessions at each site. As a result, DTN process maps were created and potential failures and their causes, frequency, severity, and existing safeguards were identified. For each failure, a risk priority number and criticality score were calculated; failures were then ranked, with the highest scores representing the most critical failures and targets for intervention. We detected a total of 70 failures in 50 process steps and 76 failures in 42 process steps at the community hospital and academic medical center, respectively. At the community hospital, critical failures included (1) delay in registration because of Emergency Department overcrowding, (2) incorrect triage diagnosis among walk-in patients, and (3) delay in obtaining consent for thrombolytic treatment. At the academic medical center, critical failures included (1) incorrect triage diagnosis among walk-in patients, (2) delay in stroke team activation, and (3) delay in obtaining computed tomographic imaging. CONCLUSIONS: Although the identification of common critical failures suggests opportunities for a generalizable process redesign, differences in the criticality and nature of failures must be addressed at the individual hospital level, to develop robust and sustainable solutions to reduce DTN time.
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Centros Médicos Académicos/estadística & datos numéricos , Hospitales Comunitarios/estadística & datos numéricos , Isquemia/epidemiología , Accidente Cerebrovascular/epidemiología , Enfermedad Aguda , Errores Diagnósticos , Diagnóstico por Imagen , Servicio de Urgencia en Hospital , Humanos , Isquemia/diagnóstico , Isquemia/tratamiento farmacológico , Mejoramiento de la Calidad , Accidente Cerebrovascular/diagnóstico , Accidente Cerebrovascular/tratamiento farmacológico , Terapia Trombolítica , Tiempo de Tratamiento , Activador de Tejido Plasminógeno/uso terapéutico , Resultado del Tratamiento , TriajeRESUMEN
An unintended consequence of rapid thrombolysis may be more frequent treatment of stroke mimics, nonvascular conditions that simulate stroke. We explored the relationship between door-to-needle (DTN) times and thrombolysis of stroke mimics at a single academic center by analyzing consecutive quartiles of patients who were treated with IV tissue plasminogen activator for suspected stroke from January 1, 2010 to February 28, 2014. An increase in the proportion of stroke mimic patients (6.7% in each of the 1st and 2nd, 12.9% in the 3rd, and 30% in the last consecutive case quartile; p = 0.03) and a decrease in median DTN time from 89 to 56 minutes (p < 0.01) was found. As more centers reduce DTN times, the rates of stroke mimic treatment should be carefully monitored.
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Bronchoscopy is a commonly used minimally invasive procedure for lung-cancer staging. In standard practice, however, physicians differ greatly in their levels of performance. To address this concern, image-guided intervention (IGI) systems have been devised to improve procedure success. Current IGI bronchoscopy systems based on virtual bronchoscopic navigation (VBN), however, require involvement from the attending technician. This lessens physician control and hinders the overall acceptance of such systems. We propose a hands-free VBN system for planning and guiding bronchoscopy. The system introduces two major contributions. First, it incorporates a new procedure-planning method that automatically computes airway navigation plans conforming to the physician's bronchoscopy training and manual dexterity. Second, it incorporates a guidance strategy for bronchoscope navigation that enables user-friendly system control via a foot switch, coupled with a novel position-verification mechanism. Phantom studies verified that the system enables smooth operation under physician control, while also enabling faster navigation than an existing technician-assisted VBN system. In a clinical human study, we noted a 97% bronchoscopy navigation success rate, in line with existing VBN systems, and a mean guidance time per diagnostic site = 52 s. This represents a guidance time often nearly 3 min faster per diagnostic site than guidance times reported for other technician-assisted VBN systems. Finally, an ergonomic study further asserts the system's acceptability to the physician and long-term potential.
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Broncoscopía/métodos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/cirugía , Cirugía Asistida por Computador/métodos , Tomografía Computarizada por Rayos X/métodos , Anciano , Broncoscopios , Broncoscopía/instrumentación , Diseño de Equipo , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fantasmas de Imagen , Cirugía Asistida por Computador/instrumentaciónRESUMEN
OBJECTIVES: Systems theory suggests that there should be relatively high correlations among quality measures within an organization. This was an examination of hospital performance across three types of quality measures included in Medicare's Hospital Inpatient Value-Based Purchasing (HVBP) program: emergency department (ED)-related clinical process measures, inpatient clinical process measures, and patient experience measures. The purpose of this analysis was to determine whether hospital achievement and improvement on the ED quality measures represent a distinct domain of quality. METHODS: This was an exploratory, descriptive analysis using publicly available data. Composite scores for the ED, inpatient, and patient experience measures included in the HVBP program were calculated. Correlations and frequencies were run to examine the extent to which achievement and improvement were related across the three quality domains and the number of hospitals that were in the top quartile for performance across multiple quality domains. RESULTS: Achievement scores were calculated for 2,927 hospitals, and improvement scores were calculated for 2,842 hospitals. There was a positive, moderate correlation between ED and inpatient achievement scores (correlation coefficient of 0.50, 95% confidence interval [CI] = 0.47 to 0.53), but all other correlations were weak (0.16 or less). Only 96 hospitals (3.3%) scored in the top quartile for achievement across the three quality domains; 73 (2.6%) scored in the top quartile for improvement across all three quality domains. CONCLUSIONS: Little consistency was found in achievement or improvement across the three quality domains, suggesting that the ED performance represents a distinct domain of quality. Implications include the following: 1) there are broad opportunities for hospitals to improve, 2) patients may not experience consistent quality levels throughout their hospital visit, 3) quality improvement interventions may need to be tailored specifically to the department, and 4) consumers and policy-makers may not be able to draw conclusions on overall facility quality based on information about one domain.
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Centers for Medicare and Medicaid Services, U.S./normas , Servicio de Urgencia en Hospital/normas , Hospitales/normas , Evaluación de Procesos y Resultados en Atención de Salud/estadística & datos numéricos , Satisfacción del Paciente/estadística & datos numéricos , Indicadores de Calidad de la Atención de Salud/normas , Centers for Medicare and Medicaid Services, U.S./economía , Centers for Medicare and Medicaid Services, U.S./estadística & datos numéricos , Servicio de Urgencia en Hospital/economía , Servicio de Urgencia en Hospital/estadística & datos numéricos , Departamentos de Hospitales/economía , Departamentos de Hospitales/normas , Departamentos de Hospitales/estadística & datos numéricos , Humanos , Evaluación de Procesos y Resultados en Atención de Salud/economía , Satisfacción del Paciente/economía , Indicadores de Calidad de la Atención de Salud/economía , Indicadores de Calidad de la Atención de Salud/estadística & datos numéricos , Mecanismo de Reembolso/economía , Mecanismo de Reembolso/normas , Mecanismo de Reembolso/tendencias , Estados Unidos , Compra Basada en CalidadRESUMEN
Of patients with ST segment elevation myocardial infarction (STEMI), approximately two thirds present to a hospital not capable of percutaneous coronary intervention. Transfer to a STEMI-receiving center delays time to reperfusion in patients with STEMI, but factors that affect this delay have not been well studied. We performed a 3-round modified Delphi study to identify system practices that minimize transfer time to a STEMI-receiving center. A comprehensive literature review was used to identify candidate system practices. Emergency medical services, emergency medicine, and cardiology experts were invited to participate. Consensus was defined as 80% agreement that a variable was "very important (5)" or "important (4)" with a mean score ≥ 4.25 or 80% agreement that a variable was "not important (1)" or "somewhat important (2)" with a mean score ≤ 1.75. In round 1, participants rated the candidate items and suggested additional items. Individual feedback was provided, and participants discussed items via conference calls before rating them again in round 2. In round 3, participants ranked the consensus items from rounds 1-2 from most to least important, and the mean score for each item was calculated. Of the 98 experts invited, 29 participated in round 1, 22 in round 2, and 14 in round 3. Participants identified 18 system practices that they agree are critical in minimizing transfer time to STEMI-receiving centers, with the most important being performance of a prehospital electrocardiogram and having established transfer protocols. These factors should be considered in the development of STEMI systems of care.
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Servicio de Cardiología en Hospital/organización & administración , Servicios Médicos de Urgencia/organización & administración , Infarto del Miocardio/terapia , Transferencia de Pacientes/organización & administración , Servicio de Cardiología en Hospital/normas , Consenso , Servicios Médicos de Urgencia/normas , Humanos , Grupo de Atención al Paciente/organización & administración , Transferencia de Pacientes/normas , Factores de TiempoRESUMEN
With the development of multidetector computed-tomography (MDCT) scanners and ultrathin bronchoscopes, the use of bronchoscopy for diagnosing peripheral lung-cancer nodules is becoming a viable option. The work flow for assessing lung cancer consists of two phases: 1) 3-D MDCT analysis and 2) live bronchoscopy. Unfortunately, the yield rates for peripheral bronchoscopy have been reported to be as low as 14%, and bronchoscopy performance varies considerably between physicians. Recently, proposed image-guided systems have shown promise for assisting with peripheral bronchoscopy. Yet, MDCT-based route planning to target sites has relied on tedious error-prone techniques. In addition, route planning tends not to incorporate known anatomical, device, and procedural constraints that impact a feasible route. Finally, existing systems do not effectively integrate MDCT-derived route information into the live guidance process. We propose a system that incorporates an automatic optimal route-planning method, which integrates known route constraints. Furthermore, our system offers a natural translation of the MDCT-based route plan into the live guidance strategy via MDCT/video data fusion. An image-based study demonstrates the route-planning method's functionality. Next, we present a prospective lung-cancer patient study in which our system achieved a successful navigation rate of 91% to target sites. Furthermore, when compared to a competing commercial system, our system enabled bronchoscopy over two airways deeper into the airway-tree periphery with a sample time that was nearly 2 min shorter on average. Finally, our system's ability to almost perfectly predict the depth of a bronchoscope's navigable route in advance represents a substantial benefit of optimal route planning.
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Broncoscopía/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Radiografía Torácica/métodos , Cirugía Asistida por Computador/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Algoritmos , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/cirugía , Masculino , Persona de Mediana Edad , Tomografía Computarizada por Rayos X/métodos , Grabación en Video , Adulto JovenRESUMEN
BACKGROUND: Sepsis is an increasing problem in the practice of emergency medicine as the prevalence is increasing and optimal care to reduce mortality requires significant resources and time. Evidence-based septic shock resuscitation strategies exist, and rely on appropriate recognition and diagnosis, but variation in adherence to the recommendations and therefore outcomes remains. Our objective was to perform a multi-institutional prospective risk-assessment, using failure mode effects and criticality analysis (FMECA), to identify high-risk failures in ED sepsis resuscitation. METHODS: We conducted a FMECA, which prospectively identifies critical areas for improvement in systems and processes of care, across three diverse hospitals. A multidisciplinary group of participants described the process of emergency department (ED) sepsis resuscitation to then create a comprehensive map and table listing all process steps and identified process failures. High-risk failures in sepsis resuscitation from each of the institutions were compiled to identify common high-risk failures. RESULTS: Common high-risk failures included limited availability of equipment to place the central venous catheter and conduct invasive monitoring, and cognitive overload leading to errors in decision-making. Additionally, we identified great variability in care processes across institutions. DISCUSSION: Several common high-risk failures in sepsis care exist: a disparity in resources available across hospitals, a lack of adherence to the invasive components of care, and cognitive barriers that affect expert clinicians' decision-making capabilities. Future work may concentrate on dissemination of non-invasive alternatives and overcoming cognitive barriers in diagnosis and knowledge translation.
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BACKGROUND: Mortality differences in weekend and weekday admissions have been observed for a variety of conditions that require aggressive early intervention. It is unknown if there is a mortality difference that exists for patients presenting to the Emergency Department (ED) with sepsis on the weekend. STUDY OBJECTIVES: We hypothesized that there is an increase in early inpatient mortality (death on day 1 or day 2 of hospitalization) among patients with sepsis who present to the ED on the weekend vs. weekdays. METHODS: We performed a cross-sectional analysis of 114,611 ED admissions with a principal diagnosis consistent with sepsis from 576 hospitals in the 2008 Nationwide Inpatient Sample. Adjusted analyses controlled for patient and hospital characteristics, and examined the likelihood of either early (day 1 or day 2 of hospitalization) or overall inpatient mortality. RESULTS: A greater proportion of patients admitted on the weekend died on day 1 and day 2 of hospitalization (5.4% vs. 4.0%, p < 0.001; and 7.5% vs. 6.9%, p = 0.001), the difference for overall inpatient mortality was not significant (17.9% vs. 17.5%, p = 0.08). The risk-adjusted odds ratio (OR) of day 1 and day 2 early inpatient mortality of weekend vs. weekday admissions was 1.10 (95% confidence interval [CI] 1.04-1.17) and 1.08 (95% CI 1.03-1.14), respectively; the association with overall inpatient mortality was not significant (OR 1.03, 95% CI 1.00-1.07). CONCLUSIONS: Patients admitted through the ED with sepsis on the weekend had a greater likelihood of early mortality, but not overall mortality, when compared to patients admitted on weekdays.
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Atención Posterior/estadística & datos numéricos , Servicio de Urgencia en Hospital/estadística & datos numéricos , Sepsis/mortalidad , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Estudios Transversales , Femenino , Mortalidad Hospitalaria , Hospitalización , Humanos , Masculino , Persona de Mediana Edad , Factores de Tiempo , Estados Unidos/epidemiología , Adulto JovenRESUMEN
STUDY OBJECTIVE: The Centers for Medicare & Medicaid Services currently endorses a door-to-balloon time of 90 minutes or less for patients presenting to the emergency department (ED) with ST-segment elevation myocardial infarction. Recent evidence shows that a door-to-balloon time of 60 minutes significantly decreases inhospital mortality. We seek to use a proactive risk assessment method of failure mode, effects, and criticality analysis (FMECA) to evaluate door-to-balloon time process, to investigate how each component failure may affect the performance of a system, and to evaluate the frequency and the potential severity of harm of each failure. METHODS: We conducted a 2-part study: FMECA of the door-to-balloon time system and process of care, and evaluation of a single institution's door-to-balloon time operational data using a retrospective observational cohort design. A multidisciplinary group of FMECA participants described the door-to-balloon time process to then create a comprehensive map and table listing all process steps and identified process failures, including their frequency, consequence, and causes. Door-to-balloon time operational data were assessed by "on" versus "off" hours. RESULTS: Fifty-one failure points were identified across 4 door-to-balloon time phases. Of the 12 high-risk failures, 58% occurred between ECG and catheterization laboratory activation. Total door-to-balloon time during on hours had a median time of 55 minutes (95% confidence interval 46 to 60 minutes) compared with 77 minutes (95% confidence interval 68 to 83 minutes) during off hours. CONCLUSION: The FMECA revealed clear areas of potential delay and vulnerability that can be addressed to decrease door-to-balloon time from 90 to 60 minutes. FMECAs can provide a robust assessment of potential risks and can serve as the platform for significant process improvement and system redesign for door-to-balloon time.
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Angioplastia Coronaria con Balón/normas , Infarto del Miocardio/terapia , Cateterismo Cardíaco/normas , Servicio de Urgencia en Hospital/normas , Humanos , Infarto del Miocardio/mortalidad , Calidad de la Atención de Salud , Estudios Retrospectivos , Medición de Riesgo , Análisis y Desempeño de Tareas , Factores de Tiempo , Insuficiencia del TratamientoRESUMEN
Bronchoscopy is a major step in lung cancer staging. To perform bronchoscopy, the physician uses a procedure plan, derived from a patient's 3D computed-tomography (CT) chest scan, to navigate the bronchoscope through the lung airways. Unfortunately, physicians vary greatly in their ability to perform bronchoscopy. As a result, image-guided bronchoscopy systems, drawing upon the concept of CT-based virtual bronchoscopy (VB), have been proposed. These systems attempt to register the bronchoscope's live position within the chest to a CT-based virtual chest space. Recent methods, which register the bronchoscopic video to CT-based endoluminal airway renderings, show promise but do not enable continuous real-time guidance. We present a CT-video registration method inspired by computer-vision innovations in the fields of image alignment and image-based rendering. In particular, motivated by the Lucas-Kanade algorithm, we propose an inverse-compositional framework built around a gradient-based optimization procedure. We next propose an implementation of the framework suitable for image-guided bronchoscopy. Laboratory tests, involving both single frames and continuous video sequences, demonstrate the robustness and accuracy of the method. Benchmark timing tests indicate that the method can run continuously at 300 frames/s, well beyond the real-time bronchoscopic video rate of 30 frames/s. This compares extremely favorably to the ≥ 1 s/frame speeds of other methods and indicates the method's potential for real-time continuous registration. A human phantom study confirms the method's efficacy for real-time guidance in a controlled setting, and, hence, points the way toward the first interactive CT-video registration approach for image-guided bronchoscopy. Along this line, we demonstrate the method's efficacy in a complete guidance system by presenting a clinical study involving lung cancer patients.
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Broncoscopía/métodos , Procesamiento de Imagen Asistido por Computador/métodos , Cirugía Asistida por Computador/métodos , Cirugía Torácica Asistida por Video/métodos , Tomografía Computarizada por Rayos X/métodos , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Algoritmos , Femenino , Humanos , Pulmón/anatomía & histología , Pulmón/diagnóstico por imagen , Pulmón/patología , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana EdadRESUMEN
STUDY OBJECTIVE: Medicare's new, mandatory Hospital Inpatient Value-Based Purchasing Program introduces financial rewards or penalties to hospitals according to achievement or improvement on several publicly reported quality measures. Our objective was to describe hospital reporting on the 4 emergency department (ED)-related program measures, variation in performance on the ED measures across hospital characteristics, and the characteristics of hospitals that were more likely to receive performance scores based on improvement versus achievement. METHODS: This was an exploratory, descriptive analysis. We merged 2008 to 2010 performance data from Hospital Compare with the 2009 American Hospital Association Annual Survey. We calculated a composite score for the 4 ED measures and used Kruskal-Wallis tests to examine differences in performance across hospital characteristics. We also examined differences in the percentage of scores that were awarded according to improvement versus achievement. RESULTS: There were 2,927 hospitals that qualified for the value-based purchasing program and were included in the analysis. For-profit hospitals received the highest scores; public hospitals and hospitals lacking The Joint Commission (TJC) accreditation received the lowest scores. Public hospitals had the largest share of scores awarded according to improvement (39.8%); for-profit hospitals had the lowest (27.8%). CONCLUSION: We found variation in performance by hospital characteristics on the ED-related program measures. Although public and non-TJC-accredited hospitals trailed in performance, they showed strong signs of improvement, signaling that performance gaps by ownership and accreditation may decrease. Considering the increasing scope of the value-based purchasing program, ED leaders should monitor both achievement and improvement on the 4 ED-related program measures.
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Servicio de Urgencia en Hospital/normas , Medicare/normas , Indicadores de Calidad de la Atención de Salud/normas , Compra Basada en Calidad/normas , Servicio de Urgencia en Hospital/estadística & datos numéricos , Humanos , Mejoramiento de la Calidad , Calidad de la Atención de Salud/normas , Calidad de la Atención de Salud/estadística & datos numéricos , Estados UnidosRESUMEN
Positron emission tomography computed tomography (PET-CT) images are increasingly being used for guidance during percutaneous biopsy. However, due to the physics of image acquisition, PET-CT images are susceptible to problems due to respiratory and cardiac motion, leading to inaccurate tumor localization, shape distortion, and attenuation correction. To address these problems, we present a method for motion correction that relies on respiratory gated CT images aligned using a deformable registration algorithm. In this work, we use two deformable registration algorithms and two optimization approaches for registering the CT images obtained over the respiratory cycle. The two algorithms are the BSpline and the symmetric forces Demons registration. In the first optmization approach, CT images at each time point are registered to a single reference time point. In the second approach, deformation maps are obtained to align each CT time point with its adjacent time point. These deformations are then composed to find the deformation with respect to a reference time point. We evaluate these two algorithms and optimization approaches using respiratory gated CT images obtained from 7 patients. Our results show that overall the BSpline registration algorithm with the reference optimization approach gives the best results.
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BACKGROUND: Severe sepsis is a high-mortality disease, and early resuscitation decreases mortality. Do-not-resuscitate (DNR) status may influence physician decisions beyond cardiopulmonary resuscitation, but this has not been investigated in sepsis. OBJECTIVE: Among Emergency Department (ED) severe sepsis patients, define the incidence of DNR status, prevalence of central venous catheter placement, and vasopressor administration (invasive measures), and mortality. METHODS: Retrospective observational cohort of consecutive severe sepsis patients to single ED in 2009-2010. Charts abstracted for DNR status on presentation, demographics, vitals, Sequential Organ Failure Assessment (SOFA) score, inpatient and 60-day mortality, and discharge disposition. Primary outcomes were mortality, discharge to skilled nursing facility (SNF), and invasive measure compliance. Chi-squared test was used for univariate association of DNR status and outcome variables; multivariate logistic regression analyses for outcome variables controlling for age, gender, SOFA score, and DNR status. RESULTS: In 376 severe sepsis patients, 50 (13.3%) had DNR status. DNR patients were older (79.2 vs 60.3 years, p < 0.001) and trended toward higher SOFA scores (7 vs. 6, p = 0.07). DNR inpatient and 60-day mortalities were higher (50.5% vs. 19.6%, 95% confidence interval [CI] 15.9-44.9%; 64.0% vs. 24.9%, 95% CI 25.1-53.3%, respectively), and remained higher in multivariate logistic regression analysis (odds ratio [OR] 3.01, 95% CI 1.48-6.17; OR 3.80, 95% CI 1.88-7.69, respectively). The groups had similar rates of discharge to SNF, and in persistently hypotensive patients (n = 326) had similar rates of invasive measures in univariate and multivariate analyses (OR 1.19, 95% CI 0.45-3.15). CONCLUSION: In this sample, 13.3% of severe sepsis patients had DNR status, and 50% of DNR patients survived to hospital discharge. DNR patients received invasive measures at a rate similar to patients without DNR status.
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Cateterismo Venoso Central/estadística & datos numéricos , Órdenes de Resucitación , Sepsis , Vasoconstrictores/uso terapéutico , Anciano , Servicio de Urgencia en Hospital/estadística & datos numéricos , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Estudios Retrospectivos , Sepsis/mortalidad , Sepsis/terapiaRESUMEN
OBJECTIVE: A common strategy for excluding coronary artery disease among patients presenting with low-risk chest pain is observation unit (OU) admission with serial cardiac biomarkers and stress testing for cardiac risk stratification. Patients with positive- or indeterminate-stress tests are often admitted for cardiac catheterization despite a low likelihood of disease. The aim of this study is to estimate the cost-effectiveness of computed tomography of the coronary arteries (CTCA) in the OU for the evaluation of low-risk chest pain patients with indeterminate- or positive-stress test results. METHODS: We conducted a decision analytic study to compare health outcomes and costs between 3 cardiac risk-stratification strategies in a population of patients at low cardiac risk admitted to the OU, who later had indeterminate- or abnormal-stress tests. Our population and test characteristics were based on data obtained both from the published literature and from a retrospective cohort review previously performed at our institution. The 3 strategies compared were (1) A CTCA strategy in which patients with positive- or indeterminate-stress tests subsequently underwent CTCA, and only received catheterization if results were positive, (2) A standard-of-care arm in which all patients with positive- or indeterminate-stress tests were admitted for catheterization, and (3) A do-nothing strategy in which all patients were discharged home after stress testing regardless of outcome. Outcomes measured were cost of care and life expectancy. Sensitivity analysis was performed with a multivariate Monte Carlo methodology. RESULTS: Both the CTCA and standard-of-care strategies dominated the do-nothing strategy in the base case. When comparing the standard-of-care with the CTCA strategy, the incremental cost-effectiveness ratio was $3,423,309 per additional year of life gained. Sensitivity analysis showed that below a willingness to pay of $600,000 per additional year of life, CTCA was the most likely strategy to be cost-effective. CONCLUSIONS: In this computer-modeled analysis, the addition of CTCA following positive- or indeterminate-stress tests to an OU cardiac risk-stratification pathway for low-risk chest pain patients achieved significant cost savings with a small decrease in life expectancy per patient. Adding CTCA after indeterminate- or positive-stress test results is a cost-effective intervention for further risk-stratifying low-risk chest pain patients in the OU setting before proceeding to traditional coronary angiography.