Search PubMed⌕ Search

Biomedical subjects

T K Lim

Publications and source records attributed to T K Lim.

At least 55 records · Page 3Linked to original sources
PubMed1999

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.

DNA Probes↗
PubMed1999

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.

Aged↗
PubMed1999

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.

Aged↗
PubMed1999

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.

Anti-Asthmatic Agents↗
PubMed1998

Peak expiratory flow rate guided protocol did not improve outcome in emergency room asthma.

UNLABELLED: BACKGROUND AND AIMS OF STUDY: All current international practice guidelines recommend that treatment of acute asthma in the emergency room (ER) should be guided by the peak expiratory flow rate (PEFR). The aim of this study was to assess the efficacy of a PEFR guided protocol in treating ER asthma. METHODS: We compared two different management protocols in adult asthmatics who presented to the ER with acute exacerbations. The routine protocol (RP) assessed and dispensed patients according to overall subjective and clinical response without predetermined criteria. The peak protocol (PP) used serial measurements of PEFR to guide intensity of bronchodilator treatment and fitness for hospital discharge. On the PP, a threshold PEFR of > or = 60% predicted had to be achieved before the patient could be discharged from the ER. RESULTS: There were 79 patients in the RP group and 70 in the PP group. There was no significant difference between the two groups in baseline PEFR, PEFR after treatment and percentage increase in PEFR with treatment. The PP resulted in a higher hospital admission rate than RP. CONCLUSION: We conclude that in the management of acute asthma in the ER, a PEFR guided protocol neither improved overall PEFR response to treatment nor reduced admission rates when compared with current management as it is practised in Singapore.

Acute Disease↗
PubMed1998

Ventilatory strategies for acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is a severe condition that has a high mortality. Mechanical ventilation is required and concepts have evolved over the last few decades as to the methods and principles guiding such ventilatory support. In particular, volutrauma as a feature of ventilator-associated lung injury has been well documented, leading to pressure-limited strategies with consequent permissive hypercapnia. Such an approach is in direct contrast to traditional ventilatory teaching of high tidal volumes and normal PaCO2. Current strategies therefore emphasis lower tidal volumes, adequate positive end-expiratory pressure (PEEP), minimum FiO2, and the use of pressure-control modes (plus or minus inverse-ratio ventilation). Hypercapnia is allowed to develop, and adjunctive methods are employed to improve oxygenation in order to minimise the "pressure-cost" of maintaining adequate oxygenation. With such an approach, overall mortality is reported to be around 40%.

Adult↗
PubMed1998

Efficacy of the conventional diagnostic approach to pulmonary tuberculosis.

OBJECTIVE: The aim of this study was to evaluate the efficacy of the current clinical approach to the diagnosis of culture positive pulmonary tuberculosis (PTB) in hospitalised adult patients. METHOD: We examined the case records and chest X-rays (CXR) of 199 adult patients with culture positive PTB diagnosed from 1993 to 1995. Patients were divided into two groups: early treatment (ET) and delayed treatment (DT) of PTB. DT were patients who received treatment only after respiratory specimens had returned with positive culture results. We also compared the CXR of the DT group with a group of age, sex matched patients who did not have PTB (control). Usual CXR pattern for PTB was defined as: upper lobe acinar shadows, upper lobe cavitation or miliary pattern. RESULTS: There were 199 patients with a mean age of 56 (19). One patient was HIV antibody positive and 27% were diabetics. There were 143 (72%) patients in the ET group and 56 (28%) in the DT group. The ET group was significantly younger and more likely to show usual features and cavitary disease on the CXR than the DT group. The diabetic patients had significantly more frequent cavitation than non-diabetics. When compared to a control group without PTB, the DT group was significantly more likely to show usual CXR pattern and less likely to have a clear CXR. CONCLUSIONS: The conventional approach to the diagnosis of PTB is reasonably accurate and efficient enough for the majority of patients. The delay in the diagnosis and treatment of PTB was more common among elderly patients, patients with negative smear results and atypical CXR features. If PTB is suspected in elderly patients, an early decision should be made between empiric treatment and further diagnostic testing.

Adult↗
PubMed1997

Electrochemical disinfection of drinking water using an activated-carbon-fiber reactor capable of monitoring its microbial fouling.

An electrochemical reactor employing activated carbon fibers (ACF) was constructed for the disinfection of bacteria in drinking water. The application of an alternating potential of 1.0 V and -0.8 V versus a saturated calomel electrode, for disinfecting and desorbing bacteria, enabled reactor operation for 840 h. Drinking water was passed through the reactor in stop/flow mode: 300 ml/min flow for 12 h and no flow for 12 h, alternately. The bacterial cell density in treated water was always been less than 20 cells/ml. It was also found that the formation of biofilm on the ACF reactor caused an increase in current, enabling the self-detection of microbial fouling.

Absorption↗
PubMed1997

Excessive bronchoconstriction induced by histamine and effects of volume history in patients with bronchial asthma.

The aim of this study was to examine the inter-relationships between the different effects of deep breaths and histamine provocation on airway function in patients with bronchial asthma. Group 1 consisted of 38 consecutive out-patients with newly diagnosed mild asthma, group 2 consisted of 20 patients with bronchial asthma of varying severity who were studied during clinical remission. We measured bronchial responsiveness (BR) to histamine inhalation as the dose of histamine which provoked a 20% fall in FEV1 (PD20). The fall in forced vital capacity (FVC) after inhaling the highest dose of histamine during each BR test was calculated and expressed as percentage of the value measured at baseline (delta FVC in percentage). We studied the effects of deep breaths on airway caliber in group 2 patients by comparing isovolumic flow rates on partial (P) and maximal (M) forced expiratory flow volumes curves expressed as the M/P ratio. The changes in residual volume (RV) after deep breaths (delta RV) were expressed as a percentage of the largest VC measured on the composite M and P curves. The patients in group 1 had significantly higher PD20 and lower delta FVC than patients in group 2. There was, however, no significant correlation between PD20 and delta FVC measurements in individual patients (r < 0.1, P > 0.05). The M/P ratio was significantly related to delta FVC (r = -0.6, P < 0.006). There was also a significant positive relation between the magnitude of increase in residual volume following deep breaths (delta RV) and the degree of fall in FVC following histamine inhalation (delta FVC) (r = 0.65, P = 0.001). This significant relationship between the degree of airway closure after a deep breath and airway closure after histamine challenge is a new finding. In patients with bronchial asthma, the effects of a deep breath on airway function may be indicative of the tendency for airway closure during BR testing.

Adult↗
PubMed1997

Controlled trial of intrapleural streptokinase in the treatment of pleural empyema and complicated parapneumonic effusions.

OBJECTIVE: To compare the efficacy of adjunctive intrapleural streptokinase (SK) with simple closed chest tube drainage (Drain) in the treatment of empyemas and complicated parapneumonic effusions. METHOD: This was a controlled study of 52 patients (mean age, 57 years; 41 men) with pleura space sepsis. Forty patients (77%) had empyema and 12 had complicated parapneumonic effusions. Twenty-nine patients were treated with Drain only while 23 received, in addition, repeated daily SK, 250,000 U in saline solution (mean, 5.3 days). RESULTS: The two groups of patients had comparable degrees of peripheral blood leukocytosis, frequency of loculated effusions, pleural fluid pH, and lactate dehydrogenase levels. Infective organisms were isolated in 54% of which 32% were anaerobic and 21% were polymicrobial infections. The incidence of surgical decortication was 17% and mortality was 15%. A significantly larger volume of pleural fluid was drained from patients in the SK treatment group (2.0 [1.5] L) than those in the Drain treatment group (1.0 [1.01] L). There were no significant differences, however, between the two treatment groups in terms of duration before defervescence, duration of hospital stay, the need for surgical intervention, or mortality rates. CONCLUSION: We conclude that thrombolytic therapy increased the volume of fluid drained from pleural empyemas but did not markedly reduce morbidity and mortality.

Adult↗
PubMed1997

Severe asthma.

OBJECTIVE: To determine the morbidity and mortality of severe asthmatic patients needing intensive care in Singapore. DESIGN: Retrospective review of admissions from January 1987 to March 1993. SETTING: Urban teaching hospital. PATIENTS: Forty-eight patients with forty-nine admissions with severe asthma requiring admission into the medical intensive care unit. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Forty-eight patients with forty-nine admissions with severe asthma requiring admission into the medical intensive care unit were identified during the study period. The majority (69%) were admitted directly into the intensive care from the emergency room, and 16 cases (33%) had cardiorespiratory arrest, of whom half survived hypoxic brain damage. Mechanical ventilation was needed in 30 cases (61%), with a mean duration of 3.3 days, and 2 pneumothoraces were recorded. Those who needed mechanical ventilation had significantly higher arterial pCO2 (98 mmHg vs 62 mmHg) and a lower arterial pH (7.1 vs 7.3). However, not all patients with hypercapnia (> 50 mmHg) needed mechanical ventilation. Hospital mortality was 12% (6 cases), while two others with hypoxic brain damage died shortly after hospital discharge. Mortality was not predicted by previous need for mechanical ventilation, length of asthma, or age. For the ventilated group alone, hospital mortality was higher at 20%. On an average follow-up of 133 weeks, there was only one death. Mean potassium level was 3.9 mmol/L with 13 cases (28%) of hypokalemia (< 3.6 mmol/L). CONCLUSION: Severe asthma was associated with an appreciable mortality. Hypercapnia did not guarantee the need for mechanical ventilation. For those that survived their acute episode, there was one mortality out of 40 survivors after an average of 2 years of follow-up.

Adult↗
PubMed1997

Emerging pathogens for pneumonia in Singapore.

The death rate from pneumonia in Singapore has increased steadily over the past decade. The emerging respiratory pathogens may have contributed to this increased mortality. New challenges have arisen from changes in the characteristics of the host and the susceptibilities of the various pathogens to antibiotics. There has been a 60-fold increase in the incidence of penicillin resistance in Streptococcus pneumoniae, the major pathogen for community-acquired pneumonia (CAP). Gram-negative bacilli are the major pathogens in severe CAP with Klebsiella pneumonia being the most frequently isolated organism. There has been a small increase in the number of cases of Legionnaire's disease and a marked increase in the incidence of melioidosis. While the overall incidence of tuberculosis has been unchanged, the number of non-residents with tuberculosis has doubled in the past 5 years. The rising prevalence of human immunodeficiency Virus infection is reflected in an increasing number of apparently healthy young men who present with CAP caused by Pneumocystis carinii. There is increasing resistance to antibiotics among gram-negative bacilli and Staphylococcus aureus, the dominant pathogens in hospital-acquired pneumonia. New strategies are urgently needed to prevent the emergence of pathogens in the hospital environment which may be resistant to all known antibiotics.

AIDS-Related Opportunistic Infections↗
PubMed1996

Simplified method for measuring urinary leukotriene E4.

The conventional method for measuring urinary leukotriene E4 (LTE4) is by reversed-phase high-performance liquid chromatography (RP-HPLC), followed by radioimmunoassay (RIA) or enzyme immunoassay (EIA). We measured urinary LTE4 levels by two methods, HPLC with EIA and EIA alone after initial crude extraction of urine using an octadecyl reversed-phase extraction cartridge (Sep-Pak). Ninety-three urine samples from normal subjects and patients with bronchial asthma and adult respiratory distress syndrome were tested. The results showed that urinary LTE4 levels measured by EIA significantly correlated with those measured by HPLC plus EIA in the three groups (r = 0.88, 0.85, 0.68). The absolute values of urinary LTE4 measured by EIA without HPLC purification were higher than by EIA with HPLC purification. This suggests that HPLC may not be necessary for routine urinary LTE4 quantitation in different clinical situations.

Adult↗
PubMed1996

Granulocyte-macrophage colony-stimulating factor overrides the immunosuppressive function of corticosteroids on rat pulmonary dendritic cells.

Pulmonary dendritic cells (DC) are present in extremely small numbers, but they are the most potent antigen-presenting cells in the lungs. Pure populations of DC can be isolated from the lung following collagen digestion, Percoll gradient centrifugation, removal of phagocytic cells and flow cytometric sorting for cells which exhibit high levels of surface major histocompatibility complex (MHC) class II molecules. Exogenous GM-CSF enhances this immunostimulatory capacity of the pulmonary DC. Soluble factors produced by type II airway epithelial cells and interstitial macrophages also enhance the immunostimulating capacity of pulmonary DC while alveolar macrophages suppress it. Thus, the function of DC may be regulated by locally produced cytokines. Corticosteroids are widely used as immunosuppressive agents in pharmacotherapy. While these agents are known to inhibit T cell proliferation and macrophage activation, their effects on DC are not known. We found that dexamethasone (Dex) pretreatment resulted in about a 50% reduction in the immunostimulatory capacity of rat pulmonary DC. This was associated with downregulation of MHC class II (Ia) expression. Dex-induced suppression of DC function could be restored with GM-CSF. We conclude that corticosteroids downregulate antigen-presenting capacity by direct suppression of pulmonary DC. This immunosuppressive effect of corticosteroids on DC may, however, be abrogated by exogenous GM-CSF. Corticosteroids and GM-CSF are therapeutic agents with potent direct immunomodulating effects on DC.

Adrenal Cortex Hormones↗