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.

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.

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.

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.

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.

Asthma in the elderly--a more severe disease

OBJECTIVE

To determine the severity of asthma in the elderly compared to the younger asthmatics.

DESIGN

Cross-sectional study.

SETTING

University outpatient asthma clinic.

SUBJECTS

Asthmatics seen over a 6 month period in 1997.

RESULTS

There were 154 patients and 16% were elderly (> 65 years) asthmatics. The elderly asthmatics were on significantly more anti-asthmatic medications (2.3 +/- 1.1 vs. 1.6 +/- 0.9, p < 0.001), and their clinical severity was significantly worse than their younger counterparts (Step 2.2 +/- 1.2 vs. 1.7 +/- 1.0, p < 0.001). Near-fatal asthma episodes were also more common in the elderly asthmatics (39% vs 13%, chi 2 test p < 0.01).

CONCLUSIONS

Elderly asthmatics appear to have more severe asthma as evidenced by the increase in near-fatal episodes, and their increased clinical severity.

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.

General electromagnetic density of modes for a one-dimensional photonic crystal

In this paper, we present more general, exact, and concise expressions for calculating the electromagnetic density of modes (EDOM) in one dimension photonic crystal (superlattice) for E and H polarizations. The expression is used for numerical computation of the EDOM in the lower-index (dielectric constant) layer. We discuss the difference between the EDOM in high- and low-index layers as due to the presence of waveguiding modes and evanescent-excited Bloch modes in the higher-index layer. Two methods of computation are presented to compute the EDOM in the lower-index layer. We suggest the possibility of using the EDOM to establish population inversion, which may be useful for higher-frequency lasers (e.g., x rays) and control any radiative processes. We also elaborate on the limitations of the results of Alvarado Rodriguez et al. as due to the approximation used in the evaluation of partial differentialomega/ partial differentialk(y,z) for nabla(k)omega and comment on the limitations of the one-dimensional EDOM expression of Bendickson et al.

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.

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.

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.

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.

Recent advances in the management of pleural sepsis: what is the evidence?

The management of pleural sepsis involves early diagnosis, administration of appropriate antibiotics, recognition of poor prognostic features and timely intervention to drain the infected pleural space. Important recent advances in the management of pleural sepsis include better imaging techniques, the use of flexible image-guided drainage catheters, adjunctive intrapleural thrombolytic therapy and the introduction of interventional thoracoscopy. These advances have been augmented, in the past year, by results from prospective controlled studies comparing different therapeutic options. This review describes an evidence-based approach to the management of pleural sepsis which incorporates recent therapeutic advances.

Fulminant necrotising fasciitis caused by Vibrio parahaemolyticus

We report a patient with septicaemia and fulminant necrotising fasciitis caused by Vibrio parahaemolyticus. This organism is strongly associated with seawater exposure and seafood ingestion. The patient recovered due to expedient management, prompt recognition of the organism, appropriate antimicrobial cover and surgical debridement. The lesson to be learned is that this organism should be clinically suspected and recognised from its typical history of injury and fulminant clinical progress as a delay in diagnosis and treatment may result in an increased risk of mortality.

Asthma management: evidence based studies and their implications for cost-efficacy

This review attempts to infer a cost-effective strategy for the management of bronchial asthma based on evidence from randomized controlled trials. Acute severe asthma should be treated with short-acting inhaled beta-agonists followed by a short course of oral steroids. Decisions on hospital admission should be made within 1 to 2 hours and prolonged treatment in emergency departments avoided. A comprehensive educational and drug optimizing program will prevent chronic illness and relapse. Educational programs should be brief but intensive, supervised by asthma specialists and incorporate self monitoring of symptoms plus written action plans. Peak expiratory flow monitoring should not be mandated for all patients. Inhaled corticosteroids (ICS) are the most cost-effective drugs for the long term prevention of asthma. ICS should be started at low doses. If the symptoms of asthma are not well controlled by moderate doses of ICS, high dose ICS treatment should be avoided and add on medication prescribed instead. Oral bronchodilators are less expensive add on medication than long-acting inhaled beta-agonists.

Hospitalised low-risk community-acquired pneumonia: outcome and potential for cost-savings

Fine et al. from USA have identified a sub-group of patients with community-acquired pneumonia (CAP) with a low risk of mortality and suggested that it may be cost-effective to manage them as outpatients. The aims of this study were: to evaluate the outcome of low risk CAP patients that were hospitalised in our local setting, and to gauge the number of such patients in order to estimate the potential cost-savings by treating them as outpatients, as well as the safety of such an approach. All patients with CAP admitted to our hospital from 1 April 1997 to 1 March 1998 were enrolled into this prospective cohort study. Low-risk patients were identified, and their hospital outcome compared with other patients. Hospitalisation charges were obtained from the Finance Department. There were 226 patients with CAP. The average age was 64 years with a range of 12 to 96 years. The median hospital stay was 6 days. Mortality was 13.7%. 16.8% required admission to the ICU; none of these were low-risk patients. There were 47 (21%) low-risk patients, and there was no mortality in this group. They had significantly shorter hospital stay (6.4 days versus 10 days) and lower hospitalisation charges ($2,160 versus $5,770) compared to other CAP patients. Only one low-risk patient had a positive blood culture. In conclusion, nearly one-fifth of our CAP admissions consisted of low-risk patients that experienced no mortality, and required a significantly shorter hospitalisation. The management of such patients who are young (< or = 50 years), with no serious co-morbidities in an outpatient setting may be a cost-effective strategy, and this group of patients consumed 9% of the total hospitalisation charges for CAP.

Lymphangiomyomatosis: radiological and measured lung function deterioration after contrast-enhanced computed tomography

Pulmonary lymphangiomyomatosis (LAM) is a rare disease of unknown aetiology which occurs exclusively in women, usually of reproductive age. The findings on CT and high-resolution CT (HRCT) are well described and characteristic, and in a young woman they are virtually pathognomonic. A case of symptomatic, radiological and measured lung function deterioration following contrast-enhanced CT in a patient with LAM are reported here. These observations, to the authors' knowledge, have never been reported before. The authors attempt to explain these observations based on the known pathology of LAM.

The role of rapid diagnostic tests for tuberculosis in Singapore

There have been major advances in molecular techniques which rapidly identify mycobacterial DNA in clinical specimens. This has culminated in the approval by the United States Food and Drug Administration (FDA) of two rapid diagnostic tests (RDT) for tuberculosis. The FDA only licensed these tests for use in AFB smear positive patients. The role of these tests in smear negative disease is undefined. This article reviews the data on efficacy of RDT in the diagnosis of AFB smear negative PTB and proposes an alogrithm which incorporates RDT in the routine diagnosis of PTB.

Empirical treatment with fibrinolysis and early surgery reduces the duration of hospitalization in pleural sepsis

The efficacy of three different treatment protocols was compared: 1) simple chest tube drainage (Drain); 2) adjunctive intrapleural streptokinase (IP-SK); and 3) an aggressive empirical approach incorporating SK and early surgical drainage (SK+early OP) in patients with pleural empyema and high-risk parapneumonic effusions. This was a nonrandomized, prospective, controlled time series study of 82 consecutive patients with community-acquired empyema (n=68) and high-risk parapneumonic effusions (n=14). The following three treatment protocols were administered in sequence over 6 years: 1) Drain (n=29, chest catheter drainage); 2) IP-SK (n=23, adjunctive intrapleural fibrinolysis with 250,000 U x day(-1) SK); and 3) SK+early OP (n=30, early surgical drainage was offered to patients who failed to respond promptly following initial drainage plus SK). The average duration of hospital stay in the SK+early OP group was significantly shorter than in the Drain and IP-SK groups. The mortality rate was also significantly lower in the SK+early OP than the Drain groups (3 versus 24%). It was concluded that an empirical treatment strategy which combines adjunctive intrapleural fibrinolysis with early surgical intervention results in shorter hospital stays and may reduce mortality in patients with pleural sepsis.

Cause, treatment and outcome of patients with life-threatening haemoptysis

BACKGROUND

Massive haemoptysis is a life-threatening situation which requires immediate medical attention and intervention. We reviewed 23 patients with life-threatening haemoptysis to document the cause, describe the treatment of these patients and to determine which form of treatment had a better outcome.

DESIGN

Retrospective case study.

METHODS

Consecutive patients were reviewed and data collected for the underlying cause, treatment and outcome of patients with life-threatening haemoptysis.

RESULTS

Out of 23 patients, nine patients had active pulmonary tuberculosis and nine patients had post-tuberculous lung disease. Fifteen patients underwent bronchial embolisation, one patient had surgical resection and seven patients had received medical treatment. Five patients required intubation. Bronchial embolisation was significantly better than medical treatment at immediate cessation of haemoptysis (p < 0.05). Three (13%) patients died from haemoptysis. Follow-up duration averaged 16 months.

CONCLUSIONS

The most common causes of haemoptysis were pulmonary tuberculosis and post-tuberculous bronchiectasis. Urgent bronchial artery embolisation was better at immediate cessation of haemoptysis than medical treatment.