Thesis (MScPhysio (Physiotherapy))--University of Stellenbosch, 2007. / AIM: The aim of this study was threefold. Firstly to determine the effect of passive thoracic flexion-rotation (PTFR) movement on the total static compliance of the respiratory system, tidal volume, respiratory rate and plateau pressure. Secondly, to identify the interventions used by physiotherapists to influence compliance and thirdly to compare the effects of these interventions. DESIGN: A one group, pre-test-post-test physiological study and a systematic review of the literature were performed. METHOD: A randomised sample consisting of 18 intubated and ventilated subjects of varying periods of ventilation and various conditions was obtained. The interventions used included tactile stimulation and PTFR movements. Subjects acted as their own controls. Objective variables namely tidal volume, respiratory rate and plateau pressure were recorded by a research assistant. These measurements were taken immediately following the intervention and repeated again three times in an interval of 20 minutes after the movement was discontinued. Total static compliance of the respiratory system was calculated as tidal volume divided by the difference between plateau pressure and positive end-expiratory pressure. The search strategy for the systematic review included the searching of five databases, a secondary search (pearling) and a hand search. Two independent reviewers agreed on the inclusion of articles and their methodological quality. A critical review form (Law et al 1998) was used for scoring methodological quality and a hierarchy of evidence for allocating the level of evidence of each study. Inclusion criteria were experimental studies, written in English and published after January 1995. Participants were intubated, ventilated humans, over the age of 18.

Submitted in fulfilment of the requirements of the Master's Degree in Technology: Radiography, Durban University of Technology, 2013. / ABSTRACT Escalating current healthcare needs coupled with the dire shortage of radiologists created a climate in countries abroad to extend the role of the radiographer (Williams 2006). The South African radiography profession demonstrates similar if not worse challenges within the radiology services (Gqweta 2012). The human resource needs in the healthcare sector creates a gap in the provision of radiology services (Brandt et al 2007). Often under these circumstances radiographers are asked by emergency department's personnel to comment on radiographic appearances (Hardy and Snaith 2007). Radiographers do provide opinions in order to facilitate patient management (Gqweta 2012). Since the chest x-ray is the most commonly performed x-ray examination in x-ray departments (Manning, Leach and Bunting, 2000), it is assumed that most requests for an opinion may be directed for the clarification of this x-ray examination. Therefore radiographers need to have an in-depth understanding of the knowledge and skills related to the identification of patterns on chest images. The aim of the study was to establish and describe the current chest image interpretation skills, knowledge and perceptions of diagnostic radiographers in eThekwini Health District of KwaZulu-Natal (KZN) with regard to image interpretation. METHOD: A quantitative study using a descriptive design with a qualitative aspect using an interpretive design was employed. A simple random sample of hospitals within the eThekwini health district that have x-ray departments was drawn. All diagnostic radiographers that met the inclusion criteria from within these hospitals were invited to partake in the study and all were registered with the Health Profession Council of South Africa (HPCSA). A questionnaire was utilised to collect data on the perceptions and knowledge of diagnostic radiographers on radiographic appearances. A reporting template was provided for the respondents to report on ten (10) chest images and to standardise responses . Accuracy , specificity and sensitivity measurements were utilised to determine the image interpretation knowledge and skills of radiographers without formal training on image interpretation. The SPSS (Statistical Package for the Social Sciences) version 21 was utilised for the raw data capture and analysis. RESULTS Forty two (42) radiographers participated in the study. Almost half (46%) of the respondents were chief radiographers and twenty four point four percent (24.4%) of the respondents were senior radiographers . X-ray department managers and community service radiographers each had twelve (12%) percent representation. The majority of the respondents frequently performed chest x-rays. Furthermore they regularly observe Pulmonary Tuberculosis (PTB) abnormal patterns more than those of pneumonia and lung cancer on chest radiographs. The respondents indicated that there is a need for them to extend their roles to include image interpretation. This will ensure that radiographers are responsive to current health care needs perpetuated by the absence of radiologists and the ever rapidly increasing population. The majority of the respondents were able to identify abnormal appearances on the radiographs (high sensitivity). However there was a proportional decrease on the identification and recognition of the normal appearances (specificity). There was no respondent that obtained a mark of eighty (80%) on the image interpretation knowledge assessment section. CONCLUSION Radiographers are able to identify abnormal patterns on chest images. However they are unable to adequately exclude an abnormality (low specificity). Furthermore they lack the ability to adequately describe abnormal radiographic/radio logical appearances. The image interpretation knowledge base of radiographers is limited and specific. Therefore there is a need for an intensive education and training for prospective reporting radiographers.

As afecções pulmonares são muito comuns na rotina clinica de pequenos animais. No entanto, por apresentarem sintomas inespecíficos, muitas vezes o diagnóstico dessas doenças torna-se limitado. Recursos de imagem como a radiografia e a ultrassonografia torácica são válidos como exames de triagem, mas somente a biopsia pulmonar garante um diagnóstico especifico da doença. Desse modo a toracoscopia fornece um meio minimamente invasivo de diagnóstico para as doenças torácicas e oferece os benefícios de melhor iluminação e ampliação da imagem, quando comparado com a toracotomia. Nesta pesquisa foram avaliadas as técnicas de biópsia pulmonar através da agulha cortante guilhotinada e da pinça de biopsia, guiadas por toracoscopia pelo acesso transdiafragmático em cães que apresentavam imagem sugestiva de nódulo pulmonar em exame radiográfico prévio. Foram utilizados 14 cães da rotina de atendimento do Hospital de Clinicas Veterinárias (HCV) da Faculdade de Veterinária (FAVET) da UFRGS, independente de raça, sexo, idade e peso corporal. Somente animais com nódulos visíveis na radiografia torácica e que apresentaram exames pré-cirúrgicos sem alterações que impediam de serem anestesiados foram incluídos no estudo. Os animais foram posicionados em decúbito dorsal e foram feitos dois acessos à cavidade torácica, um primeiro portal intercostal, para introdução dos dispositivos de biopsia, e outro portal paraxifoide transdiafragmático para introdução do endoscópio. Com cada instrumento de biopsia foram coletadas três amostras do mesmo nódulo ou de nódulos macroscopicamente semelhantes e próximos quando o tamanho destes era inferior a um centímetro. As amostras foram encaminhadas para exame histopatológico no laboratório de Patologia Veterinária da FAVET/UFRGS. A frequência cardíaca (FC), frequência respiratória (FR), saturação de oxigênio (SpO2) e pressão arterial média (PAM) foram aferidas em seis momentos diferentes do procedimento: após a indução da anestesia (T1), Após o estabelecimento do pneumotórax (T2), após a introdução do primeiro trocarte (T3), após a introdução do segundo trocarte (T4), após a coleta dos fragmentos da biopsia (T5) e após reestabelecer a pressão negativa no tórax (T6). O tempo cirúrgico foi cronometrado da incisão ao fechamento da ferida, e foram registradas quaisquer complicações cirúrgicas. No pós-operatório os animais foram avaliados quanto à presença de enfisema subcutâneo, hematoma, seroma, infecção local e deiscência de pontos. Não foi necessário converter os procedimentos toracoscópicos para cirurgia convencional em nenhum dos animais. Concluiu-se tratar de uma técnica segura, rápida sem complicações trans e pós-operatórias. Ambos dispositivos permitiram aquisição de material suficiente para analise histopatológica das alterações pulmonares, no entanto a agulha cortante guilhotinada apresentou maior eficácia principalmente em nódulos pulmonares de maior diâmetro. O acesso transdiafragmático mostrou-se eficiente para exploração de ambos os hemotóraces. / Lung diseases are common in the small animals clinical routine. However, diagnosis is usually affected due to nonspecific symptoms. Imaging features such as radiography and chest ultrasound are acceptable screening tests, although lung biopsy can provides precise diagnosis. Thus, thoracoscopy provides a minimally invasive diagnostic assessment for chest diseases and offers the benefits such as improved illumination and magnification of the image when compared to thoracotomy. In this study we evaluated the transdiaphragmatic thoracoscopic-assisted techniques of lung biopsy through the guillotine cutting needle and biopsy forceps, in dogs presenting radiographic suspicion on pulmonary tumors. Fourteen dogs regardless of breed, gender, age and body weight admitted at the Hospital of Veterinary Clinics (HCV) of the Veterinary College (FAVET) of UFRGS were assessed. Inclusion criteria was presence of nodules on chest radiography and triage tests without changes that could hinder general anesthesia and surgical approach. The animals were positioned in dorsal recumbence and two thoracoscopic ports were established: the first port for working instruments; the second paraxyphoid port for the telescope. Three samples were collected using each sampling method from each lesion or from tumors macroscopically similar whenever their size was less than one centimeter. The samples were sent for histopathological examination in the Veterinary Pathology Laboratory of the FAVET / UFRGS. Heart rate (HR), respiratory rate (RR), peripheral oxygen saturation (SpO2) and mean arterial pressure (MAP) were measured in six time points during the procedure: after induction of anesthesia (T1); after the establishment of pneumothorax (T2); after introduction of the first trocar (T3); after insertion of the second trocar (T4); after biopsy sampling (T5); and after reestablishment of the thoracic negative pressure (T6). The animals were evaluated for the presence of subcutaneous emphysema, hematoma, seroma, local infection and dehiscence. No conversion to open surgery was necessary during the thoracoscopic procedures in any patient. Thoracoscopic-assisted biopsy using both guillotine needle and biopsy forceps was a safe and fast technique, without perioperative complications. Both devices provided good quality samples for histopathological analysis of lung abnormalities. However, the cutting guillotine needle was more efficient especially in larger pulmonary nodules. The transdiaphragmatic access provided optimal approach for both hemithoraces.

As afecções pulmonares são muito comuns na rotina clinica de pequenos animais. No entanto, por apresentarem sintomas inespecíficos, muitas vezes o diagnóstico dessas doenças torna-se limitado. Recursos de imagem como a radiografia e a ultrassonografia torácica são válidos como exames de triagem, mas somente a biopsia pulmonar garante um diagnóstico especifico da doença. Desse modo a toracoscopia fornece um meio minimamente invasivo de diagnóstico para as doenças torácicas e oferece os benefícios de melhor iluminação e ampliação da imagem, quando comparado com a toracotomia. Nesta pesquisa foram avaliadas as técnicas de biópsia pulmonar através da agulha cortante guilhotinada e da pinça de biopsia, guiadas por toracoscopia pelo acesso transdiafragmático em cães que apresentavam imagem sugestiva de nódulo pulmonar em exame radiográfico prévio. Foram utilizados 14 cães da rotina de atendimento do Hospital de Clinicas Veterinárias (HCV) da Faculdade de Veterinária (FAVET) da UFRGS, independente de raça, sexo, idade e peso corporal. Somente animais com nódulos visíveis na radiografia torácica e que apresentaram exames pré-cirúrgicos sem alterações que impediam de serem anestesiados foram incluídos no estudo. Os animais foram posicionados em decúbito dorsal e foram feitos dois acessos à cavidade torácica, um primeiro portal intercostal, para introdução dos dispositivos de biopsia, e outro portal paraxifoide transdiafragmático para introdução do endoscópio. Com cada instrumento de biopsia foram coletadas três amostras do mesmo nódulo ou de nódulos macroscopicamente semelhantes e próximos quando o tamanho destes era inferior a um centímetro. As amostras foram encaminhadas para exame histopatológico no laboratório de Patologia Veterinária da FAVET/UFRGS. A frequência cardíaca (FC), frequência respiratória (FR), saturação de oxigênio (SpO2) e pressão arterial média (PAM) foram aferidas em seis momentos diferentes do procedimento: após a indução da anestesia (T1), Após o estabelecimento do pneumotórax (T2), após a introdução do primeiro trocarte (T3), após a introdução do segundo trocarte (T4), após a coleta dos fragmentos da biopsia (T5) e após reestabelecer a pressão negativa no tórax (T6). O tempo cirúrgico foi cronometrado da incisão ao fechamento da ferida, e foram registradas quaisquer complicações cirúrgicas. No pós-operatório os animais foram avaliados quanto à presença de enfisema subcutâneo, hematoma, seroma, infecção local e deiscência de pontos. Não foi necessário converter os procedimentos toracoscópicos para cirurgia convencional em nenhum dos animais. Concluiu-se tratar de uma técnica segura, rápida sem complicações trans e pós-operatórias. Ambos dispositivos permitiram aquisição de material suficiente para analise histopatológica das alterações pulmonares, no entanto a agulha cortante guilhotinada apresentou maior eficácia principalmente em nódulos pulmonares de maior diâmetro. O acesso transdiafragmático mostrou-se eficiente para exploração de ambos os hemotóraces. / Lung diseases are common in the small animals clinical routine. However, diagnosis is usually affected due to nonspecific symptoms. Imaging features such as radiography and chest ultrasound are acceptable screening tests, although lung biopsy can provides precise diagnosis. Thus, thoracoscopy provides a minimally invasive diagnostic assessment for chest diseases and offers the benefits such as improved illumination and magnification of the image when compared to thoracotomy. In this study we evaluated the transdiaphragmatic thoracoscopic-assisted techniques of lung biopsy through the guillotine cutting needle and biopsy forceps, in dogs presenting radiographic suspicion on pulmonary tumors. Fourteen dogs regardless of breed, gender, age and body weight admitted at the Hospital of Veterinary Clinics (HCV) of the Veterinary College (FAVET) of UFRGS were assessed. Inclusion criteria was presence of nodules on chest radiography and triage tests without changes that could hinder general anesthesia and surgical approach. The animals were positioned in dorsal recumbence and two thoracoscopic ports were established: the first port for working instruments; the second paraxyphoid port for the telescope. Three samples were collected using each sampling method from each lesion or from tumors macroscopically similar whenever their size was less than one centimeter. The samples were sent for histopathological examination in the Veterinary Pathology Laboratory of the FAVET / UFRGS. Heart rate (HR), respiratory rate (RR), peripheral oxygen saturation (SpO2) and mean arterial pressure (MAP) were measured in six time points during the procedure: after induction of anesthesia (T1); after the establishment of pneumothorax (T2); after introduction of the first trocar (T3); after insertion of the second trocar (T4); after biopsy sampling (T5); and after reestablishment of the thoracic negative pressure (T6). The animals were evaluated for the presence of subcutaneous emphysema, hematoma, seroma, local infection and dehiscence. No conversion to open surgery was necessary during the thoracoscopic procedures in any patient. Thoracoscopic-assisted biopsy using both guillotine needle and biopsy forceps was a safe and fast technique, without perioperative complications. Both devices provided good quality samples for histopathological analysis of lung abnormalities. However, the cutting guillotine needle was more efficient especially in larger pulmonary nodules. The transdiaphragmatic access provided optimal approach for both hemithoraces.

As afecções pulmonares são muito comuns na rotina clinica de pequenos animais. No entanto, por apresentarem sintomas inespecíficos, muitas vezes o diagnóstico dessas doenças torna-se limitado. Recursos de imagem como a radiografia e a ultrassonografia torácica são válidos como exames de triagem, mas somente a biopsia pulmonar garante um diagnóstico especifico da doença. Desse modo a toracoscopia fornece um meio minimamente invasivo de diagnóstico para as doenças torácicas e oferece os benefícios de melhor iluminação e ampliação da imagem, quando comparado com a toracotomia. Nesta pesquisa foram avaliadas as técnicas de biópsia pulmonar através da agulha cortante guilhotinada e da pinça de biopsia, guiadas por toracoscopia pelo acesso transdiafragmático em cães que apresentavam imagem sugestiva de nódulo pulmonar em exame radiográfico prévio. Foram utilizados 14 cães da rotina de atendimento do Hospital de Clinicas Veterinárias (HCV) da Faculdade de Veterinária (FAVET) da UFRGS, independente de raça, sexo, idade e peso corporal. Somente animais com nódulos visíveis na radiografia torácica e que apresentaram exames pré-cirúrgicos sem alterações que impediam de serem anestesiados foram incluídos no estudo. Os animais foram posicionados em decúbito dorsal e foram feitos dois acessos à cavidade torácica, um primeiro portal intercostal, para introdução dos dispositivos de biopsia, e outro portal paraxifoide transdiafragmático para introdução do endoscópio. Com cada instrumento de biopsia foram coletadas três amostras do mesmo nódulo ou de nódulos macroscopicamente semelhantes e próximos quando o tamanho destes era inferior a um centímetro. As amostras foram encaminhadas para exame histopatológico no laboratório de Patologia Veterinária da FAVET/UFRGS. A frequência cardíaca (FC), frequência respiratória (FR), saturação de oxigênio (SpO2) e pressão arterial média (PAM) foram aferidas em seis momentos diferentes do procedimento: após a indução da anestesia (T1), Após o estabelecimento do pneumotórax (T2), após a introdução do primeiro trocarte (T3), após a introdução do segundo trocarte (T4), após a coleta dos fragmentos da biopsia (T5) e após reestabelecer a pressão negativa no tórax (T6). O tempo cirúrgico foi cronometrado da incisão ao fechamento da ferida, e foram registradas quaisquer complicações cirúrgicas. No pós-operatório os animais foram avaliados quanto à presença de enfisema subcutâneo, hematoma, seroma, infecção local e deiscência de pontos. Não foi necessário converter os procedimentos toracoscópicos para cirurgia convencional em nenhum dos animais. Concluiu-se tratar de uma técnica segura, rápida sem complicações trans e pós-operatórias. Ambos dispositivos permitiram aquisição de material suficiente para analise histopatológica das alterações pulmonares, no entanto a agulha cortante guilhotinada apresentou maior eficácia principalmente em nódulos pulmonares de maior diâmetro. O acesso transdiafragmático mostrou-se eficiente para exploração de ambos os hemotóraces. / Lung diseases are common in the small animals clinical routine. However, diagnosis is usually affected due to nonspecific symptoms. Imaging features such as radiography and chest ultrasound are acceptable screening tests, although lung biopsy can provides precise diagnosis. Thus, thoracoscopy provides a minimally invasive diagnostic assessment for chest diseases and offers the benefits such as improved illumination and magnification of the image when compared to thoracotomy. In this study we evaluated the transdiaphragmatic thoracoscopic-assisted techniques of lung biopsy through the guillotine cutting needle and biopsy forceps, in dogs presenting radiographic suspicion on pulmonary tumors. Fourteen dogs regardless of breed, gender, age and body weight admitted at the Hospital of Veterinary Clinics (HCV) of the Veterinary College (FAVET) of UFRGS were assessed. Inclusion criteria was presence of nodules on chest radiography and triage tests without changes that could hinder general anesthesia and surgical approach. The animals were positioned in dorsal recumbence and two thoracoscopic ports were established: the first port for working instruments; the second paraxyphoid port for the telescope. Three samples were collected using each sampling method from each lesion or from tumors macroscopically similar whenever their size was less than one centimeter. The samples were sent for histopathological examination in the Veterinary Pathology Laboratory of the FAVET / UFRGS. Heart rate (HR), respiratory rate (RR), peripheral oxygen saturation (SpO2) and mean arterial pressure (MAP) were measured in six time points during the procedure: after induction of anesthesia (T1); after the establishment of pneumothorax (T2); after introduction of the first trocar (T3); after insertion of the second trocar (T4); after biopsy sampling (T5); and after reestablishment of the thoracic negative pressure (T6). The animals were evaluated for the presence of subcutaneous emphysema, hematoma, seroma, local infection and dehiscence. No conversion to open surgery was necessary during the thoracoscopic procedures in any patient. Thoracoscopic-assisted biopsy using both guillotine needle and biopsy forceps was a safe and fast technique, without perioperative complications. Both devices provided good quality samples for histopathological analysis of lung abnormalities. However, the cutting guillotine needle was more efficient especially in larger pulmonary nodules. The transdiaphragmatic access provided optimal approach for both hemithoraces.

目的：本研究主要目的是建立預測模型來判定矽肺發生的累積風險從而推薦適宜的胸片照射年限並從而評估常規監測和推薦監測策略的成本效益。此外，本研究還評價了常規診斷和驗證性診斷的符合度以及在驗證性診斷中邀請的三位專家之間的符合度。 / 方法：總計有3492男性接塵工人在1964年1月1日到1974年12月31日期間進入本隊列並隨訪至2008年12月31日。不同閱片專家根據中國最新塵肺病診斷標準 （GBZ70-2009））分別閱片總計9084張。對專家之間閱片結果的兩兩比較和兩種診斷結果的比較均采用Cohen’s Kappa檢驗。應用三種篩選方法（強制所有變量同時進入模型，後退逐步篩選，以及Least Absolute Shrinkage and Selection Operator (LASSO)篩選。LASSO模型作為最優模型，以分數量表的方式來表達。根據分數，把工人分成高、中、低危險組，並估計這三組不同危險水平工人的累積危險度。運用0.1% 累積危險度來判定不同危险的工人及不同期別的矽肺病人的射線照射年限。多狀態Markov模型用於計算矽塵暴露工人不同狀態的年轉移概率，並應用Markov成本效益分析方法來估計每獲得一個生命年的成本效益。 / 結果：截至2008年底，本矽塵暴露隊列共計發現298例矽肺病人（累計發病率為8.53%），死亡1347例（死亡比例為38.57%）。本研究發現常規診斷和驗證性診斷有很好的符合度 （Kappa值為0.89， 95%可信區間為0.88-0.91）。基於LASSO模型的分數量表具有很好的診斷識別能力 （ROC曲線下面積為0.83， 95%可信區間為0.81-0.86）。根據0.1%累積危險度標準，我們判定低危險組工人第一次射線照射的時間為第11年，推薦每兩年隨訪一次；中等危險組工人和高危險組工人的第一次射線照射時間分別為第11年和第5年，推薦每年隨訪一次。矽肺病人未晉級到三期以前均一年隨訪一次。矽塵暴露工人的年轉移概率為：從健康狀態向疑似病例轉移的概率為0.0198，從疑似病例向一期矽肺轉移的概率為0.038，從一期矽肺向二期矽肺轉移的概率為0.0516，從二期矽肺向三期矽肺轉移的概率為0.059，從三期矽肺向死亡轉移的概率為0.18。在1964到2008年間，診斷一例矽肺病例平均花費醫療成本為21853.11美元，非醫療成本為5993.30美元。模擬10,000矽塵暴露工人在未來40年按照當前的狀態轉移概率，應用常規的職業健康檢查為手段獲得一個生命年的成本效益為43.60美元，應用推薦的職業健康檢查為手段獲得一個生命年的成本效益為46.99美元。 / 結論：本研究在最優預測模型的基礎上為不同矽肺危險度的矽塵暴露工人首次提供了科學的證據來判定射線照射的適宜年限，亦為未來矽塵暴露工人的職業健康監測提供了科學理論依據，雖然本研究推薦的監測策略獲得同常規策略相類似的成本和效益。 / Objectives: The primary objective was to develop prediction models for determining the optimal intervals of chest radiographic surveillance for workers exposed to silica dust; the second primary objective is to assess the cost per case identification and compare the cost per life year gained under routine medical surveillance program with that under the recommended program for workers exposed to silica dust in China. In addition, the inter-rater agreement amongst three invited radiologists on rereading the chest radiographs and the agreement between the original diagnoses of silicosis (from routine reports) and the verified diagnoses reassessed by the three experts were also evaluated. / Methods: A total of 3492 male workers exposed to silica dust in an iron ore during the period 1964 - 1974 were recruited into this retrospective cohort study. All cohort members were followed up through the end of 2008 to observe the occurrence of silicosis and overall profile of mortality. All 9084 chest X-ray films were reread by three radiologists who had been qualified as experts at the national level according to the Chinese National Diagnostic Criteria of Pneumoconiosis (GBZ70-2009). The diagnosis of silicosis made by the panel of these three invited experts was referred to the “verified diagnosis“. Cohen’s Kappa test was used to test inter-rater agreements of three invited readers on chest radiographs and the agreement on the diagnosis of silicosis obtained from routine medical surveillance (i.e., the original routine diagnosis) was compared with those verified by the 3 qualified readers (i.e., the verified diagnosis). The multivariate Cox’s proportional hazard regression models were developed to predict the silicosis occurrence based on three selection approaches entry of all predictors at the same time, backward stepwise selection, and Least Absolute Shrinkage and Selection Operator (LASSO) selection. The LASSO model showed the best model fit which was thus regarded as the final model for predicting a score chart. / Based on this practically used score chart, we then classified workers into three groups of different risk levels of silicosis (low, moderate, and high). We estimated the cumulative risk of silicosis over years of follow-up for these three groups of workers at different risk levels. We used 1 per thousand of cumulative risk for developing silicosis as a “benchmark“ to determine the intervals of radiologic surveillance for workers with different risks of silicosis. Multi-state Markov model was used to calculate the transition probabilities of different states of silicosis and the analysis on cost and effectiveness was performed. / Results: By the end of 2008, the cumulative incidence rate of silicosis was 8.53% (298 silicosis cases) and a total of 1347 deaths (38.57%) were observed. / Good inter-rater agreements were observed amongst three invited radiologists for rereading all the chest films. Kappa value for the agreement between the original diagnoses and the verified diagnoses was 0.89 (95% confidence interval [95%CI], 0.88-0.91). / The model with the best fit was LASSO Cox model which showed a good discrimination with an area of 0.83 (95%CI, 0.81-0.86) under the receiver operating characteristic (ROC) curve. We classified workers into 3 risk groups according to the score chart obtained from the LASSO Cox model, and found the observed probabilities matched well to the predictions. According to 1 per thousand “benchmark“, we can determine that the initial interval of radiographic surveillance for workers in the low risk group was 11 years and a subsequent biyearly examination was recommended. The initial examination interval was 11 years and 5 years respectively for workers in the middle and high risk group, and then a yearly examination was recommended. For patients with silicosis, an annual radiological surveillance program was recommended regardless of the stage of pneumoconiosis. / According to results from multi-state model, we estimated that the yearly transition probability was 0.0198 for silica dust exposed workers from healthy state to the suspected silicosis cases (sojourn time = 47 years), 0.0338 from suspected silicosis cases to silicosis stage one (sojourn time = 23 years), 0.0516 from silicosis stage one to stage two (sojourn time = 9 years), 0.059 from silicosis stage two to stage three (sojourn time = 6 years), and 0.18 from silicosis stage three to death (sojourn time = 5 years). / During the period 1964 to 2008, the average direct medical cost spent on identifying one silicosis case was US$ 21853.11 and the non-medical cost for identifying one case was US$ 5993.30 per case. The estimated medical cost regarding per life year gained was US$ 43.60 under the routine medical surveillance program and it would be US$ 46.99 if the newly recommended surveillance program is adopted. / Conclusion: This study is the first to provide scientific evidence on determining the optimal intervals of radiographic surveillance for workers at different risk levels of silicosis based on the ‘best’ prediction model. Although our study revealed similar cost and effectiveness for using the recommended occupational health examination strategy compared with the routine program, this study is the first to provide scientific theory for guiding evidence-based occupational medical surveillance on workers exposed to silica dust in the world. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Chen, Minghui. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 195-210). / Abstract also in Chinese. / Abstract (English) --- p.i / Abstract (Chinese) --- p.v / Acknowledgements --- p.vii / List of contents --- p.ix / List of tables --- p.xv / List of figures --- p.xviii / List of main abbreviations --- p.xx / Chapter Section I --- Introduction and Literature Review --- p.1 / Chapter Chapter 1 --- Introduction --- p.2 / Chapter Chapter 2 --- Literature Review of Medical Examination, Prediction model and Economic Evaluation in Silicosis --- p.7 / Chapter 2.1 --- The aims of this literature review --- p.7 / Chapter 2.2 --- Search strategies and selection criteria --- p.7 / Chapter 2.3 --- Searching results --- p.8 / Chapter 2.4 --- Critical appraisal criteria and quality of selected studies --- p.9 / Chapter 2.4.1 --- Critical appraisal criteria --- p.9 / Chapter 2.4.2 --- Quality of selected studies --- p.10 / Chapter 2.5 --- Overview of effectiveness of chest radiography in medical surveillance of silicosis for workers exposed to silica dust --- p.15 / Chapter 2.5.1 --- Occupational medical surveillance for workers exposed to silica dust --- p.15 / Chapter 2.5.2 --- Comparison of CT or HRCT and chest radiography --- p.16 / Chapter 2.5.3 --- Comparison of digital radiography (DR) and chest radiography --- p.17 / Chapter 2.5.4 --- Other tests to be relevant to silicosis diagnosis --- p.23 / Chapter 2.5.5 --- The effectiveness of chest radiography in medical surveillance and diagnosis of silicosis --- p.24 / Chapter 2.5.6 --- Comparison between the ILO Classification and the Chinese Diagnostic criteria of pneumoconiosis --- p.25 / Chapter 2.6 --- Overview of application of prediction model in silicosis and a review on methodology in prediction model --- p.32 / Chapter 2.6.1 --- Application of prediction model in occupational diseases --- p.32 / Chapter 2.6.2 --- Overview of application of predicting model in pneumoconiosis including silicosis in China in recent 10 years --- p.34 / Chapter 2.6.3 --- Development of prediction model and the applications from practical perspectives --- p.35 / Chapter 2.7 --- A review on economic evaluation in occupational diseases and the screening interval analyses --- p.42 / Chapter 2.7.1 --- An overview on economic evaluation in pneumoconiosis --- p.42 / Chapter 2.7.2 --- Overview of economic evaluation in occupational health and safety and screening interval analyses --- p.44 / Chapter 2.7.3 --- Overview for methodology of performing CEA --- p.45 / Chapter 2.8 --- Research gaps were found from this literature review --- p.52 / Chapter Section II --- Objectives and Methods --- p.53 / Chapter Chapter 3 --- General aims and objectives --- p.54 / Chapter 3.1 --- General aims --- p.54 / Chapter 3.2 --- Primary objectives --- p.54 / Chapter 3.3 --- Secondary objective --- p.54 / Chapter Chapter 4 --- Methodology and Research Plans --- p.55 / Chapter 4.1 --- Study Design --- p.55 / Chapter 4.2 --- The cohort --- p.55 / Chapter 4.3 --- Follow-up --- p.58 / Chapter 4.4 --- Data Collection --- p.58 / Chapter 4.4.1 --- Baseline information --- p.58 / Chapter 4.4.2 --- Diagnosis of silicosis and the verification --- p.59 / Chapter 4.4.3 --- Occupational hygiene monitoring data --- p.60 / Chapter 4.4.4 --- Cost data of medical examination --- p.61 / Chapter 4.5 --- Data Entry and Data Analyses --- p.62 / Chapter Section III --- Results and Discussions --- p.65 / Chapter Chapter 5 --- Description of the cohort --- p.66 / Chapter 5.1 --- Cohort recruitment --- p.66 / Chapter 5.2 --- Baseline characteristics --- p.69 / Chapter 5.3 --- Change of respirable silica dust concentration over time --- p.71 / Chapter 5.5 --- Occurrence of silicosis --- p.73 / Chapter 5.5.1 --- Basic characteristics of silicosis patients --- p.73 / Chapter 5.5.2 --- Trend of silicosis occurrence with calendar year --- p.78 / Chapter 5.5.3 --- Trend of silicosis occurrence with age of entering the cohort --- p.78 / Chapter 5.5.4 --- Trend of silicosis occurrence with cumulative exposure to respirable silica dust --- p.78 / Chapter 5.6 --- Survival distribution at different respirable silica dust exposure levels --- p.79 / Chapter 5.7 --- A summary of the results in Chapter 5 --- p.82 / Chapter Chapter 6 --- Agreement between the routine diagnosis of silicosis and the verified ‘new panel’ diagnosis --- p.83 / Chapter [Summary] --- p.83 / Chapter 6.1 --- Background --- p.85 / Chapter 6.2 --- Methodology --- p.86 / Chapter 6.2.1 --- The routine and the verified diagnosis of silicosis --- p.86 / Chapter 6.2.2 --- Inter-rater agreement --- p.87 / Chapter 6.3 --- Results --- p.89 / Chapter 6.3.1 --- Technical quality of chest X-ray films --- p.89 / Chapter 6.3.2 --- Inter-rater agreement amongst readers --- p.89 / Chapter 6.3.3 --- Agreement between the routine and the verified diagnosis of silicosis --- p.93 / Chapter 6.3.4 --- Agreement of the progression of silicosis between the routine and verified diagnosis --- p.95 / Chapter 6.4 --- Discussion --- p.97 / Chapter Chapter 7 --- Developing prediction model for determining the optimal intervals of chest radiographic examinations for workers at different risks of silicosis --- p.100 / Chapter [Summary] --- p.100 / Chapter 7.1 --- Background --- p.102 / Chapter 7.2 --- Methods --- p.104 / Chapter 7.2.1 --- The cohort and outcome determination --- p.104 / Chapter 7.2.2 --- Developing prediction models for silicosis --- p.107 / Chapter 7.2.3 --- Coding of Predictors --- p.113 / Chapter 7.3 --- Results --- p.118 / Chapter 7.3.1 --- Model Specifications --- p.118 / Chapter 7.3.2 --- Stepwise Selection and LASSO selection --- p.119 / Chapter 7.3.3 --- Model Validations: Stability and Optimism --- p.119 / Chapter 7.3.4 --- Model Presentations --- p.126 / Chapter 7.3.5 --- Cut-off point of follow up year for determining examination intervals --- p.130 / Chapter 7.4 --- Discussions --- p.136 / Chapter Chapter 8 --- Transition probabilities of multi-states for workers with silica dust exposure --- p.141 / Chapter [Summary] --- p.141 / Chapter 8.1 --- Background --- p.143 / Chapter 8.2 --- Methodology of multi-state model --- p.145 / Chapter 8.2.1 --- Survival data and multi-state model --- p.145 / Chapter 8.2.2 --- Markov model and transition states --- p.151 / Chapter 8.2.3 --- Model assessment --- p.153 / Chapter 8.3 --- Results --- p.154 / Chapter 8.3.1 --- Initial values specification and estimates of intensity matrix --- p.154 / Chapter 8.3.2 --- Transition probability matrix, mean sojourn times, and survival situation --- p.159 / Chapter 8.3.3 --- Observed and expected prevalence of each state for Model assessment --- p.163 / Chapter 8.4 --- Discussion --- p.165 / Chapter Chapter 9 --- Cost effectiveness analysis of occupational medical surveillance for workers exposed to silica dust --- p.168 / Chapter [Summary] --- p.168 / Chapter 9.1 --- Background --- p.170 / Chapter 9.2 --- Methodologies --- p.171 / Chapter 9.2.1 --- Costs and effectiveness --- p.171 / Chapter 9.2.2 --- Cost per silicosis identification estimation in the iron ore during 1964 to 2008 --- p.172 / Chapter 9.2.3 --- Cost effectiveness analysis in the Markov model --- p.173 / Chapter 9.3 --- Results --- p.176 / Chapter 9.3.1 --- Cost estimation and cost per silicosis identification in the iron ore cohort --- p.176 / Chapter 9.3.2 --- Cost effectiveness analysis in the Markov model --- p.181 / Chapter 9.4 --- Discussion --- p.187 / Chapter Section IV --- Conclusions and Implications --- p.191 / Chapter Chapter 10 --- Conclusions, implications, and recommendations --- p.192 / Chapter 10.1 --- Conclusions --- p.192 / Chapter 10.2 --- Implications and recommendations --- p.193 / Reference list --- p.195 / Chapter Appendix I --- Chest Radiographic Imaging of Different Diagnostic Criteria for Pneumoconiosis in China --- p.211 / Chapter Appendix II --- Diagnosis Stages among Different Diagnostic Criteria for Pneumoconiosis in China --- p.212 / Chapter Appendix III --- Publications in journals and international conferences during the PhD study --- p.213 / Chapter Supplement I --- Syntax for test proportionality of Cox model in R survival package and LASSO model in R penalized package --- p.215 / Chapter Supplement II --- Guideline of applying the prediction model in practice --- p.216 / Chapter Supplement III --- Syntax for multi-state model in R msm package --- p.221 / Chapter Supplement IV --- An example for cost estimation of adjusting inflation and exchanging --- p.222 / Chapter Supplement V --- Cost estimation of workers, suspected silicosis cases and silicosis patients in the iron ore during 1964 - 2008 --- p.223 / Chapter Supplement V (Continued) --- Cost estimation of workers, suspected silicosis cases and silicosis patients in the iron ore during 1964 - 2008 --- p.224 / Chapter Supplement VI --- Number of deaths for all cause of death in the iron ore cohort until 2008 --- p.225 / Chapter Supplement VII --- Decision tree of Markov model in the study --- p.226 / Chapter Supplement VII (Continued) --- Decision tree of Markov model in the study --- p.227

MCur / Department of Advanced Nursing Science

MCur / Department of Advanced Nursing Science