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Biomedical subjects

T K Lim

Publications and source records attributed to T K Lim.

At least 19 recordsLinked to original sources
PubMed2003

Transbronchial needle aspiration: initial experience in routine diagnostic bronchoscopy.

BACKGROUND: Transbronchial needle aspiration (TBNA) has been shown to be useful not only for the diagnosis and staging of lung cancer, its most widely studied indication, but also for many of other clinical indications. Despite this, it remains largely underutilized, mainly because of concerns with poor yield, safety, lack of experience of the bronchoscopist, and lack of cytopathological support. OBJECTIVE: To study the clinical utility and yield of TBNA as an adjunct to other conventional procedures in diagnostic bronchoscopy at a centre that was relatively inexperienced with this technique, but where there was availability of rapid on-site evaluation (ROSE). Most of the major indications for TBNA in both malignant as well as benign disease were included. SETTING: University Teaching Hospital naïve to the procedure. PATIENT AND METHODS: Forty-five consecutive patients who underwent TBNA as part of diagnostic bronchoscopy during a 2-year study period. RESULTS: TBNA gave a yield of 65% for evaluation of mediastinal disease, both benign and malignant. The overall diagnostic utility for all indications was 71% and there were no complications. CONCLUSIONS: We conclude that TBNA is a useful and safe adjunct to diagnostic bronchoscopy in routine clinical practice. It has a satisfactory yield even with an inexperienced team, if used with ROSE.

Biopsy, Fine-Needle↗
PubMed2003

Prescribing and administration of nebulized bronchodilators: a prospective audit in a university hospital.

OBJECTIVE: Inaccurate and incomplete prescribing of nebulized bronchodilators can result in uncertainty and suboptimal treatment. A prospective study was carried out to assess the completeness of prescription and the quality of bronchodilator drug administration via nebulizers. METHODOLOGY: A total of 121 consecutive inpatient nebulized bronchodilator prescriptions and treatments administered to 93 adult medical inpatients in a university hospital were studied prospectively. Five different aspects of the prescriptions were examined to assess their accuracy and completeness. The administration of each nebulizer treatment was studied using audit of medication charts and interview with ward nurses. RESULTS: No prescription was correct and complete in all five aspects assessed. The most common mistake was failure to state the type and flow rate of driving gas (100%). This was followed by failure to prescribe recommended doses of bronchodilators (46%) and failure to give unambiguous instruction on frequency of treatment (39%). It was found that in only 21.5% of instances was the administration of nebulized bronchodilator drugs optimal. CONCLUSION: This prospective audit has demonstrated major deficiencies in the prescribing and administration of nebulized bronchodilators and it has highlighted the need for a local protocol and continuing staff education. The alternative method of administering bronchodilator via metered dose inhaler with large volume spacer should be evaluated in the treatment of acute airflow obstruction in hospitalized patients.

Administration, Inhalation↗
PubMed2003

Role of clinical judgment in the application of a nucleic acid amplification test for the rapid diagnosis of pulmonary tuberculosis.

BACKGROUND: Several nucleic acid amplification (NAA) tests for Mycobacterium tuberculosis (MTB) have been licensed for the rapid diagnosis of active pulmonary tuberculosis (PTB) in respiratory secretions. There is uncertainty however regarding the practical application of these tests in clinical decision making. OBJECTIVE: To evaluate the utility of the COBAS AMPLICOR assay (Roche Diagnostics; Singapore) for MTB as applied by specialists for the rapid diagnosis of PTB in the routine clinical setting. DESIGN: A prospective study of consecutive patients suspected of PTB and tested with the AMPLICOR assay under the care of respiratory physicians. The final diagnosis was based on all relevant clinical information after at least 3 months of follow-up. Accuracy of the NAA test was compared with that of the initial expectant treatment. Expectant treatment was based on an integrated approach that incorporated clinical evaluation with results of direct smear and NAA tests. RESULTS: The incidence of PTB in 168 patients was 32%. The basis for expectant treatment of PTB was positive smear result in 47%, clinical suspicion in 26%, and positive AMPLICOR result in 23%. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the AMPLICOR test were 77%, 100%, 99%, 90%, and 93%, respectively. In comparison, they were 96%, 97%, 94%, 98%, and 97%, respectively, for the integrated clinical approach. CONCLUSIONS: In the rapid diagnosis of PTB, the clinical judgment of specialists augmented the utility of the NAA test: (1) specialists selected patients with high-to-moderate pretest probabilities, (2) they commenced treatment promptly on a positive NAA test result, and (3) they were willing to start treatment in some patients on the basis of high clinical suspicion despite negative smear and negative NAA test results.

Adolescent↗
PubMed2002

What is the optimal approach for using a direct amplification test in the routine diagnosis of pulmonary tuberculosis? A preliminary assessment.

OBJECTIVE: The aim of this study was to determine the most appropriate strategy for the rapid diagnosis of pulmonary tuberculosis (PTB) using a nucleic acid amplification (NAA) test. METHODOLOGY: This was a prospective study of 128 adult patients in whom respiratory secretions were tested for Mycobacterium tuberculosis by the AMPLICOR assay. The basis for starting PTB treatment was noted for each patient. The optimal approach was determined by using Bayes' theorem to compare different combinations of pretest probability, smear results with the AMPLICOR test. RESULTS: The incidence of PTB was 15.6%. In only one patient was treatment for PTB commenced because of a positive AMPLICOR result. The rest were managed according to the conventional approach which relied upon clinical judgment and direct smear. The optimal approach was to treat patients with high or intermediate pretest risk for PTB who returned positive AMPLICOR tests. The overall accuracies of the conventional approach, AMPLICOR test and optimal approach were 89.8, 95.3 and 96.1%, respectively. CONCLUSION: This small study suggests that NAA testing be limited to patients with high or intermediate pretest risk of PTB. In this group, positive results demand treatment while the management of those with negative results still relies on clinical judgment.

Adult↗
PubMed2002

Primary care doctors' practice in the management of adult asthma patients.

There is apparent disparity between the international guidelines on asthma management and the current practice in reality. This can be attributed to both patient's and doctor's factors. This study examines the practice of asthma management by a group of family physicians using a self-administered questionnaire. This comprises questions relating to the main principles of asthma management set by international guidelines. The results showed that majority of the doctors (>90%) in the study reviewed patient's asthma status based on symptoms, educate their patients on types of asthma medications and advised them on allergen avoidance including smoking. Fewer of them (50 to <90%) check trigger factors or inhaled device technique, nocturnal symptoms or ER visits. Even fewer doctors (<50%) bothered to check the patient's peak expiratory flow rate (PEFR) or used spirometry.

Asthma↗
PubMed2002

Emergency department asthma: compliance with an evidence-based management algorithm.

BACKGROUND: Recent surveys in emergency medicine departments show inadequacies in many aspects of acute asthma management. OBJECTIVE: The objective of this study was to evaluate the adherence to management algorithm for acute asthma in the emergency department which focused on evidence-based treatment steps rather than documentation and patient classification. METHODS: A retrospective audit of consecutive adult patients with acute exacerbations of asthma in the emergency medicine department of a university hospital managed in the context of a clinical algorithm. RESULTS: We collated information from 344 episodes of acute asthma (94% of total) over a 4-month period. The first-line treatment was nebulised bronchodilators in 97%, combination of salbutamol and ipratropium bromide in 93% and the combination in recommended dosages in 87%. Systemic corticosteroid treatment was administered to 82% of patients. A further course of systemic corticosteroid was prescribed at discharge for 94% of patients. Overall, 93% of patients received some form of systemic corticosteroid treatment. The admission rate was 35.2%, and was significantly higher in women and the elderly. Of those who were admitted, 46.2% received > or = 3 nebulised treatments and 69% received intravenous hydrocortisone. CONCLUSIONS: In the management of acute asthma, we found excellent compliance with specific treatment steps based upon clinical evidence. However, adherence to second-line treatment was less satisfactory. Nevertheless, whenever second-line treatment was complied with, reasonable outcomes were achieved. It may be more appropriate to emphasise evidence-based treatment rather than extensive documentation.

Acute Disease↗
PubMed2002

The pattern of utilisation and accuracy of a commercial nucleic acid amplification test for the rapid diagnosis of Mycobacterium tuberculosis in routine clinical practice.

BACKGROUND: Several nucleic acid amplification (NAA) tests are available for the rapid detection of Mycobacterium tuberculosis (MTB) in clinical specimens. AIMS: To identify the pattern of utilisation and accuracy of the AMPLICOR test in routine clinical practice in an acute care setting. DESIGN: A retrospective descriptive study. METHOD: We studied 159 consecutive specimens in which the AMPLICOR (Roche; Branchburg, NJ) test was requested by attending doctors. The sensitivities and specificities of the AMPLICOR for detection of active tuberculosis (TB) were calculated in relation to types of specimens, smear and culture results. RESULTS: The number of requests more than doubled from 1999 to 2000. Thirty-eight percent of the specimens were not from the respiratory tract. The majority of the specimens had requests for one or more additional test (mean 1.8). The rate of active TB was 18%. The sensitivities of the AMPLICOR on per specimen, per patient, per smear negative specimen and per smear negative patient basis were found to be 81%, 80%, 66.7% and 71.4% respectively. The specificities for these groups accordingly were 99%, 98.6%, 99% and 98.6% respectively. The sensitivity and specificity for respiratory specimens were 97.5% and 98.5%, while for non-respiratory specimens, they were 60% and 100%. In smear negative specimens, the sensitivity and specificity for respiratory specimens were 60% and 98.5%, while for non-respiratory specimens, they were 75% and 100%. The AMPLICOR assay was negative in all 21 specimens of pleural or spinal fluid. CONCLUSIONS: There is a growing demand for NAA in the rapid diagnosis of TB with a high proportion of non-respiratory specimens. The number of additional diagnostic tests performed on each specimen should be limited. In routine clinical practice, the AMPLICOR assay is a useful confirmatory test for active pulmonary TB. The utility of the AMPLICOR assay for MTB detection in exudative fluid specimens needs further evaluation.

Hospitals, University↗
PubMed2001

Construction of electrochemical flow immunoassay system using capillary columns and ferrocene conjugated immunoglobulin G for detection of human chorionic gonadotrophin.

In this paper is reported a miniaturized flow immunoassay system. Ferrocenecarboxylic acid (Fc) conjugated with anti-HCG immunoglobulin G (IgG) antibody (Fc-IgG) was prepared, and used as a novel analytical reagent. The system consists of the immunoreaction section, the capillary column packed with cation exchange resin, and the flow cell for electrochemical detection of Fc-IgG. Antibody-antigen complexes were separated from their free conjugate on the basis of differences in isoelectric point (pI) using a cation exchange capillary column. The assay yielded a linear relationship between signal and HCG concentration in the range 0-2000 mIU/ml. This simple technique enables the assay of HCG within 2 min. The cation exchange capillary column was regenerated by occasional elution with malonate buffer (pH 6.0) containing 0.5 M NaCl, to remove free conjugate. Free conjugate recovered in this manner could be reused up to eight times without significant decreases in the sensitivity of the immunoassay. This electrochemical flow immunoassay requires only minute quantities of serum and generates highly reproducible results.

Antigen-Antibody Complex↗
PubMed2001

Management of parapneumonic pleural effusion.

Parapneumonic pleural effusion is a common and potentially serious complication of pneumonia. The management of parapneumonic pleural effusion involves early diagnosis, adequate empiric antibiotic cover, and appropriate risk categorization. High-risk patients require safe and expedient drainage of the infected pleural space. The management options include thoracentesis, tube thoracostomy, adjunctive intrapleural fibrinolytic therapy, and surgical drainage. The methods of surgical drainage include thoracoscopy, thoracotomy, and decortication. The relative clinical efficacy of these treatment options has been studied in a small number of controlled clinical trials, the results of which have been systematically reviewed by expert panels. Based on the limited clinical evidence, expert reviewers were unable to recommend a best method of pleural drainage. However, the consensus is that an aggressive approach with early surgical drainage results in shorter hospital stays and may be more cost-effective than conservative management. This review discusses the clinical evidence and describes an aggressive sequential management strategy that combines intrapleural fibrinolysis with early surgical drainage.

Clinical Protocols↗
PubMed2001

Empirical treatment of chronic cough--a cost-effectiveness analysis.

Chronic cough of unknown etiology is often difficult to diagnose, thus, there exists controversy regarding the management of such patients. Although the ACCP (American College of Chest Physicians) statement in 1998 recommended that treatment should follow testing, recent evidence suggests that empirical treatment of GERD is more cost-effective than testing followed by treatment, in both chronic cough and non-cardiac chest pain. In this paper, we evaluated the cost-effectiveness in managing patients with chronic unexplained cough by building a decision model, and compared the cost-effectiveness of six most common management strategies. The outcome of our analysis demonstrates that empirical treatment is the cheapest option, while testing followed by treatment is the most expensive option with the shortest time course.

Chronic Disease↗
PubMed2000

Early discharge of patients hospitalized with acute asthma: a controlled study.

There is no consensus on the optimal length of stay and timing of release from hospital in patients admitted with acute asthma. We hypothesize that it might be safe to discharge patients from hospital once they have responded clinically to intensive anti-asthma treatment. In a non-randomized prospective controlled study, we compared two discharge protocols in consecutive patients admitted for acute severe exacerbations of bronchial asthma. Patients in group A were discharged after remission of signs and symptoms and those in group B after improvement but before complete remission of signs and symptoms. Peak expiratory flow rates (PEFR) were monitored but were not used as discharge criteria for either group. Patients with complicating disease and who were likely to be non-compliant were excluded. The length of hospital stay (LOS) and best PEFR at discharge were significantly lower in group B (87 admissions) than group A (80 admissions). The mean (+/-SD) LOS was 1.8(+/- 1) days vs. 3.5(+/- 1.4) days and best PEFR was 58(+/- 17)% predicted versus 71(+/- 15)% predicted respectively (P < 0.001 for both variables). No patient in either group relapsed within 4 weeks of discharge from hospital. We concluded that the release of asthmatics who respond promptly to intensive treatment and are compliant with medication despite incomplete resolution of symptoms, signs and PEFR at the time of discharge from hospital may not be associated with increased risk of early relapse.

Acute Disease↗
PubMed2000

Relationship between estimated pretest probability and accuracy of automated Mycobacterium tuberculosis assay in smear-negative pulmonary tuberculosis.

BACKGROUND: The AMPLICOR assay (Roche; Branchburg, NJ), a rapid direct amplification test for Mycobacterium tuberculosis, has only been licensed for use in smear-positive respiratory specimens. However, many patients with pulmonary tuberculosis (PTB) have smear-negative disease. The clinical utility of this test in patients with smear-negative PTB is unknown. OBJECTIVE: To evaluate the effect of pretest probability of PTB estimated by chest physicians on the accuracy of the AMPLICOR assay in patients with smear-negative PTB. DESIGN AND METHODS: A prospective study of consecutive patients suspected of having smear-negative PTB. Two chest physicians estimated the pretest probability of active disease (high, intermediate, and low categories). Respiratory specimens were examined with radiometric broth medium cultures and with the AMPLICOR assay for M tuberculosis. The decision on a final diagnosis of PTB was blinded to the AMPLICOR results. RESULTS: Active PTB was diagnosed in 25 of 441 patients (5.7%). The AMPLICOR assay had an overall sensitivity of 44% and a specificity of 99%. Results of the assay were negative in seven patients with culture-negative PTB. The proportions of patients in the high, intermediate, and low pretest groups were 4.5%, 19.7%, and 75.7%, respectively. The incidence of PTB for each group was 95%, 3.4%, and 0.9%, respectively. The sensitivities of the AMPLICOR assay in the three groups of patients were 47%, 33%, and 33%, respectively, while the specificities were 100%, 98%, and 99%, respectively. CONCLUSIONS: In patients suspected of having smear-negative PTB, the following conclusions were drawn: (1) the incidence of active PTB was low; (2) pretest estimates accurately discriminated between patients with high and low risk of PTB; (3) the risk of PTB was overestimated in the intermediate group; and (4) the utility of the AMPLICOR assay in the intermediate-risk group may be limited by the overestimation of disease prevalence and low test sensitivity. Further studies are needed on the role of the AMPLICOR assay in better selected patients with an intermediate risk of having smear-negative PTB.

Adolescent↗
PubMed2000

Audit of oxygen therapy in acute general medical wards following an educational programme.

INTRODUCTION: Previous studies have shown that the administration of supplementary oxygen (O2) in hospitalised patients outside the intensive care units (ICU) was usually empirical, inappropriate and not in compliance with physiological guidelines. It has been suggested that routine use of portable pulse oximeters in general wards plus in-service education of doctors and nurses may ameliorate this problem. MATERIALS AND METHODS: We introduced the use of pulse oximeters in general wards and instituted an educational programme on O2 therapy in a University Hospital. We then audited the process of O2 therapy in 100 consecutive adult medical inpatients. RESULTS: We found that, despite an educational programme and the easy availability of pulse oximeters, the quality of O2 therapy was poor. Half the patients did not receive objective pre-treatment assessment while 43% of patients were not adequately reassessed after O2 supplementation had been started. The most common error was excess use of O2 which occurred in 75% of patients. CONCLUSION: The quality of O2 therapy in the non-ICU setting was poor. Excessive O2 use was the most common error. We suggest that titration of O2 therapy, guided by pulse oximeter-guided protocols, may be needed to improve the quality and reduce the cost of O2 therapy in the hospital. This intervention may best be instituted within the environment of a continuous quality improvement model of health care delivery.

Adult↗
PubMed2000

Human genetic susceptibility to tuberculosis.

INTRODUCTION: Recent advances in the understanding of human susceptibility to tuberculosis have resulted from the application of molecular techniques to answer mechanistic questions on genetic regulation of host defense. METHODS: This review is based upon a MEDLINE search of articles relevant to human genetic susceptibility to mycobacteria. RESULTS: The impact of natural selection in shaping susceptibility to infectious disease should be taken into account when different ethnic groups are compared. Molecular typing has improved the accuracy of HLA analysis. However, most of the recent advances have come from research in non-HLA genes. Multiple non-HLA genes controlling susceptibility to tuberculosis have been identified by family-based linkage studies and population-based case-control studies. Comparative genomic studies based upon a mice model have identified a new resistance-associated protein in human macrophages. Several rare inherited disorders of mycobacterial immunity are caused by isolated gene mutations in the interferon gamma-interleukin 12 pathways. Allelic variations in the vitamin D receptor have also been related to tuberculosis. A locus on human chromosome 17q have been linked to tuberculosis in a family-based genomic screening study. CONCLUSION: Susceptibility to tuberculosis involves large number genes inherited in a complex manner. Further discoveries are expected in the wake of rapid progress in the human genome project.

Animals↗
PubMed2000

Relation between morbidity and current treatment in patients who present with acute asthma to polyclinics.

BACKGROUND: It has been suggested that resources for asthma intervention should be focused mainly on patients in the community who experience a high burden of disease. These are who patients who have acute exacerbations which require urgent treatment. AIM: To assess the morbidity and identify deficiencies in the treatment of patients who present for urgent treatment of acute exacerbations to primary care clinics. PATIENTS: Adult patients who received urgent treatment for acute exacerbation of bronchial asthma SETTING: 4 primary care polyclinics. METHODS: A cross-sectional survey of consecutive patients which related regular preventive treatment to current asthma activity. Poor asthma control was defined as step 2 or higher (American National Asthma Education and Prevention Program, report II, 1997) or > or = 2 emergency room visits in 6 months. RESULTS: There were 116 patients of whom 53% were women. The mean (SD) age was 45(15) years and duration of current exacerbation 3 (3) days. The acute symptoms were successfully treated in 93% of patients. Quick relief medication was used regularly in 91% and inhaled corticosteroids (ICS) in 55%. Oral salbutamol was prescribed in 14% of patients. The asthma was poorly controlled in 54%. In the poorly controlled group 33% were not on regular ICS treatment and 64% were not receiving "add on" medication. CONCLUSIONS: Patients treated for acute asthma in primary care clinics: (1) were older and had less acutely severe exacerbations than those who presented to emergency rooms, (2) over half had poorly controlled asthma and (3) a third of patients with poor asthma control were inadequately treated.

Acute Disease↗
PubMed2000

The rapid diagnosis of smear-negative pulmonary tuberculosis: a cost-effectiveness analysis.

OBJECTIVE: The prompt diagnosis of smear-negative pulmonary tuberculosis (PTB) is a clinical challenge. It may be achieved by a number of tests which have varying accuracies, costs and degrees of invasiveness. The objective of this study was to compare the cost-effectiveness of clinical judgement (empirical), the Roche Cobas amplicor assay for Mycobacterium tuberculosis (amplicor), acid-fast staining of bronchoalveolar lavage specimens (BAL), nucleic acid amplification tests of bronchoalveloar lavage specimens for M. tuberculosis (BAL + NAA), computed tomography (CT) and amplicor assay followed by BAL. METHODOLOGY: The range of predictive values of the various strategies were derived from published data and a new study of 441 consecutive adult patients with suspected smear-negative PTB prospectively stratified into three pretest risk groups: low, intermediate and high. The cost-effectiveness was evaluated with a decision tree model (DATA software). RESULTS: The incidence of PTB was 5.7% (4% culture positive) for the whole group, 95% in the high-risk group, 0.9% in the low-risk group and 3.4% in the intermediate-risk group. The sensitivity of the empirical approach was 49% and of the amplicor assay was 44%. Patient outcomes were expressed as life expectancy for the base case of a 58-year-old man with a pretest probability of 5.7%. At this low pretest risk the differences in life expectancies between tests was < 0.1 years and the empirical approach incurred the lowest cost. Sensitivity analysis at increasing pretest risks showed better life expectancies (approximately 1 years) for CT scan and test combinations than empirical and amplicor for additional costs of US$243-US$309. Bronchoalveolar lavage had the worst overall cost-effectiveness. CONCLUSIONS: We conclude that the pretest risk of active PTB was a key determinant of test utility; that the AMPLICOR assay was comparable to clinical judgement; that BAL was the least useful test; and that with increasing risks, CT scan and test combinations performed better. Further studies are needed to better define patients with intermediate risk for PTB and to directly compare the cost-effectiveness of more sensitive nucleic acid amplification tests such as the enhanced Gen Probe, CT scan and test combinations/sequences in these patients.

Bacteriological Techniques↗