Detection of Atrial Fibrillation After Ischemic Stroke with an Insertable Cardiac Monitor: A Systematic Review and Individual Patient Data Meta-Analysis of Randomised Clinical Trials

OBJECTIVE

In ischemic stroke patients, we compared the use of insertable cardiac monitor (ICM) versus non-ICM methods of cardiac monitoring on the incidence of atrial fibrillation (AF) detection and other clinical outcomes.

BACKGROUND

Current guidelines recommend the routine use of 12-lead electrocardiography or Holter monitoring for AF detection after ischemic stroke. Recent randomised controlled trials have investigated the impact of ICM versus non-ICM methods of cardiac monitoring for AF detection in this population. However, precise recommendations for monitoring post-stroke AF are lacking; including the optimal timing, duration, and method of electrocardiography monitoring.

METHODS

A systematic search was conducted on Embase and PubMed from database inception until 27 October 2022 to include randomised controlled trials that compared ICM with non-ICM methods of cardiac monitoring for post-stroke AF detection. This yielded 3 randomised controlled trials with a combined cohort of 1231 patients with a recent ischemic stroke. Individual patient data (IPD) was then reconstructed from Kaplan-Meier curves and analysed using the shared-frailty Cox model. An aggregate data meta-analysis was conducted for 1231 patients across all 3 studies for outcomes that could not be reconstructed using IPD.

RESULTS

One-stage meta-analysis demonstrated an increase in the hazard ratio (HR 6.01, 95% CI 3.40-10.60; p<0.001) of AF detection in patients undergoing monitoring via ICM compared to standard care. Aggregate data meta analysis revealed a significant increase in initiation of anticoagulation (OR 3.09, 95% CI 2.05 - 4.66; p<0.00001) in the ICM group. However, no significant differences in the incidence of recurrent ischemic stroke, transient ischemic attack or death were found.

CONCLUSIONS

In this meta-analysis, we found that the use of ICM increased the detection rate of post-stroke AF and the rate of anticoagulation initiation. However, this did not translate into a reduced incidence of recurrent ischemic stroke.

A musculoskeletal ultrasound program as an intervention to improve disease modifying anti-rheumatic drugs adherence in rheumatoid arthritis: a randomized controlled trial

Objectives: To evaluate the effect of a musculoskeletal ultrasound programme (MUSP) applying real-time ultrasonography with reinforcement of findings by a rheumatologist on improving disease-modifying anti-rheumatic drugs (DMARDs) adherence in rheumatoid arthritis (RA).Method: Eligible RA patients with low adherence score (< 6) on the 8-item Morisky Medication Adherence Scale (MMAS-8) were randomized to either an intervention group (receiving MUSP at baseline) or a control group (no MUSP), and followed up for 6 months. Adherence measures (patient-reported and pharmacy dispensing records) and clinical efficacy data were collected. The MUSP's feasibility and acceptability were assessed.Results: Among 132 recruited RA patients, six without baseline visits were excluded; therefore, 126 patients were analysed (62 intervention and 64 control). The primary outcome (proportion of patients with 1 month MMAS-8 score < 6) was significantly smaller (p = 0.019) in the intervention (35.48%) than the control group (56.25%). However, 3 and 6 month adherence and clinical efficacy outcomes were not significantly different between the two groups (all p > 0.05). All 62 patients completed the MUSP (mean time taken, 9.2 min), with the majority reporting moderately/very much improved understanding of their joint condition (71%) and the importance of regularly taking their RA medication(s) (79%). Most patients (90.3%) would recommend the MUSP to another RA patient.Conclusions: The MUSP improved RA patients' DMARDs adherence in the short term and was feasible and well accepted by patients. Future studies could evaluate whether repeated feedback using MUSP could help to sustain the improvement in DMARD adherence in RA patients, and whether this may be clinically impactful and cost-effective.

Intra-Arterial Adjunctive Medications for Acute Ischemic Stroke During Mechanical Thrombectomy: A Meta-Analysis

BACKGROUND AND PURPOSE

In patients with acute ischemic stroke with large vessel occlusion, the role of intra-arterial adjunctive medications (IAMs), such as urokinase, tPA (tissue-type plasminogen activator), or glycoprotein IIb/IIIa inhibitors, during mechanical thrombectomy (MT) has not been clearly established. We aim to evaluate the efficacy and safety of concomitant or rescue IAM for acute ischemic stroke with large vessel occlusion patients undergoing MT.

METHODS

We searched Medline, Embase, and Cochrane Stroke Group Trials Register databases from inception until March 13, 2020. We analyzed all studies with patients diagnosed with acute ischemic stroke with large vessel occlusion in the anterior or posterior circulation that provided data for the two treatment arms, (1) MT+IAM and (2) MT only, and also reported on at least one of the following efficacy outcomes, recanalization and 90-day modified Rankin Scale, or safety outcomes, symptomatic intracranial hemorrhage and 90-day mortality. Data were collated in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Sixteen nonrandomized observational studies with a total of 4581 patients were analyzed. MT only was performed in 3233 (70.6%) patients, while 1348 (29.4%) patients were treated with both MT and IAM. As compared with patients treated with MT alone, patients treated with combination therapy (MT+IAM) had a higher likelihood of achieving good functional outcome (risk ratio, 1.13 [95% CI, 1.03-1.24]) and a lower risk of 90-day mortality (risk ratio, 0.82 [95% CI, 0.72-0.94]). There was no significant difference in successful recanalization (risk ratio, 1.02 [95% CI, 0.99-1.06]) and symptomatic intracranial hemorrhage between the two groups (risk ratio, 1.13 [95% CI, 0.87-1.46]).

CONCLUSIONS

In acute ischemic stroke with large vessel occlusion, the use of IAM together with MT may achieve better functional outcomes and lower mortality rates. Randomized controlled trials are warranted to establish the safety and efficacy of IAM as adjunctive treatment to MT.

The open retrograde approach as an alternative for failed percutaneous access for difficult below the knee chronic total occlusions-A case series

Retrograde puncture via patent pedal vessels can be attempted in failed antegrade approach for infrapopliteal long chronic total occlusion. However in cases where the pedal vessels are unable to be visualized via duplex ultrasonography or fluoroscopy an open approach offers an additional option to a vascular surgeon for successful recanalization. Our case report highlights 3 cases where successful hybrid open retrograde approach was able to achieve recanalization of long chronic total occlusion.

Presentation of cases

The three cases in our series presented with critical limb ischaemia. All three cases had undergone duplex imaging of the affected arterial system. As the antegrade approach to cross the lesion failed a retrograde approach was attempted in all 3 cases. However when the usual modality of retrograde puncture via the use of ultrasound or fluoroscopy failed we proceeded with an open approach.

Discussion

Retrograde approach usually offers a better chance of successfully crossing a chronic total occlusion lesion. However puncturing a distal vessel successfully and traversing a catheter or guidewire across proves to be a challenge. An open approach offers an additional pathway for puncturing the target vessel when duplex imaging or fluoroscopic guidance fails.

Conclusion

Open approach is usually attempted as a last resort by many endovascular surgeons. However procedural time, contrast and radiation usage could have been cut short in cases where the distal target vessels pose a technical challenge for approach via a percutaneous method.

Use of radiosynovectomy in recurrent warfarin-related haemarthrosis in degenerative arthritis

Radiosynovectomy is a local and minimally invasive radiotherapy for treating various chronic inflammatory arthritis such as rheumatoid arthritis, osteoarthritis and haemophilic arthropathy. In haemophilic arthropathy, it reduces the frequency of haemarthrosis and delays the development of severe joint destruction, which ultimately requires surgical intervention. Its role in warfarin-related haemarthrosis is less clear. Haemarthrosis is an uncommon complication of warfarin use, and anticoagulation may need to be discontinued. We describe yttrium-90 radiosynovectomy use in a 74-year-old man with underlying ischaemic heart disease, atrial fibrillation, previous embolic stroke and recurrent haemarthrosis of an osteoarthritic right knee. Anticoagulation was vital and could not be permanently stopped. Due to continuing anticoagulation, he had multiple hospitalisations with recurrent right knee haemarthrosis. Intraarticular right knee yttrium-90 citrate colloid injection led to a cessation of haemarthrosis for eight months. We examined the available literature for the role of radiosynovectomy in such circumstances.

Pulse electroplating of copper film: a study of process and microstructure

Copper films with high density of twin boundaries are known for high mechanical strength with little tradeoff in electrical conductivity. To achieve such a high density, twin lamellae and spacing will be on the nanoscale. In the current study, 10 microm copper films were prepared by pulse electrodeposition with different applied pulse peak current densities and pulse on-times. It was found that the deposits microstructure was dependent on the parameters of pulse plating. Higher energy pulses caused stronger self-annealing effect on grain recrystallization and growth, thus leading to enhanced fiber textures, while lower energy pulses gave rise to more random microstructure in the deposits and rougher surface topography. However in the extremes of pulse currents we applied, the twin densities were not as high as those resulted from the medium or relatively high pulse currents. The highest amount of nanoscale twinning was found to form from a proper degree of self-annealing induced grain structure evolution. The driving force behind the self-annealing is discussed.

Survival among Chinese women with lung cancer in Singapore: a comparison by stage, histology and smoking status

Lung cancer generally carries a poor prognosis and the determinants of survival have been of interest. However, survival estimates in Asian populations are scarce. This study describes survival rates and their determinants in Singapore Chinese women, a primarily non-smoking population. Three hundred and twenty-six Chinese women, diagnosed with primary lung carcinoma in three major hospitals in Singapore between April 1996 and December 1998, were followed up till 31 December 2000. The Kaplan-Meier method was used for survival analysis. Two hundred and eighty (85.7%) died from the disease during follow-up. The median survival time was 0.7 years and the three-year survival was 15.8%. These survival rates are similar to those of Western populations, and they provide a basis for examining trends over time. Age at diagnosis was an independent prognostic factor [adjusted hazard ratio (relative risk) 1.4, 95% confidence intervals (CI) 1.1-1.9 for women above 65 years relative to younger women]. Most (70.5%) tumours were stage III/IV at diagnosis. Three-year survival ranged from 72% among patients with stage I tumours to 7% for stage IV tumours. Overall, there was no survival difference among different histological types in all stages combined. When limited to stages I and II cancers, adenocarcinomas were associated with a better outcome relative to other histological subtypes combined (adjusted relative risk 0.4, 95% CI 0.1-1.0). Smoking was an independent risk factor (adjusted relative risk 1.3, 95% CI 1.0-1.8). Nevertheless, non-smokers comprised 57.4% of this series, highlighting the importance of increased awareness among health professionals and the public that lung cancer is not only a disease of smokers. The high proportion of late-stage tumours in this study and the impact of disease stage on outcome underline the importance of early detection in improving survival of lung cancer.

An unusual case of nephrocutaneous fistula

An 86-year-old Caucasian woman presented with a 2-day history of a painful swelling in the left upper thigh anteriorly. She also gave a recent history of recurrent urinary tract infection associated with macroscopic haematuria, against a background of a long-term indwelling catheter for complete urinary incontinence. She denied any change in bowel habit and her weight had also been stable. Her past history included a hysterectomy, dynamic hip screw insertion for fractured right neck of femur and coronary artery disease.

On examination she was apyrexial with no signs of anaemia, jaundice or lymphadenopathy. The left thigh swelling was confirmed to be an abscess. Abdominal and rectal examinations were unremarkable. The abscess was subsequently incised and drained. A substantial amount of pus was released. Culture of the pus yielded Proteus and Escherichia coli. Unfortunately the left thigh wound failed to heal up completely resulting in a constantly discharging sinus (Figure 1).

A sonogram was then performed which revealed a fistulous track passing closely to the left greater trochanter and then superiorly projected over the left iliac wing. It then tracked medially towards the spine and particularly towards a small staghorn-like calculus on the left side. At no time was contrast seen to spill intra-abdominally (Figure 2). A subsequent computed tomography scan demonstrated that the fistulous track lay anterior to the neck of femur and passed superiorly in front of the hip joint before entering the iliacus muscle compartment retroperitoneally. The contrast then tracked superiorly until it reached the iliac crest. It continued superomedially and retroperitoneally towards the lower pole of the left kidney which contained a staghorn-like calculus. Contrast was also seen in the bladder (Figure 3). The patient did not have intravenous pyelography.

A diethylene triamine pentaacetic acid (DTPA) renogram was carried out which confirmed that the patient had a non-functioning left kidney but good function of the right kidney.

This woman subsequently underwent a left nephrectomy through a midline incision. The left kidney was shrunken and tethered retroperitoneally, and was associated with a well-defined fistulous track. The track was opened and curetted and an associated abscess cavity involving iliacus muscle drained.

Histology of the kidney confirmed chronic pyelonephritis with scarring and presence of calculus in the dilated pelvicalyceal system.

The patient made a straightforward postoperative recovery. At follow-up 3 months postoperatively, the thigh sinus had healed completely and the patient was asymptomatic.

Talk your way round--a speech interface to a virtual museum

PURPOSE

To explore the development of a speech interface to a virtual world and to consider its relevance for disabled users.

METHOD

The system was developed using mainly software that is available at minimal cost. How well the system functioned was assessed by measuring the number of times a group of users with a range of voices had to repeat commands in order for them to be successfully recognized. During an initial session, these users were asked to use the system with no instruction to see how easy this was.

RESULTS

Most of the spoken commands had to be repeated less than twice on average for successful recognition. For a set of 'teleportation' commands this figure was higher (2.4), but it was clear why this was so and could easily be rectified. The system was easy to use without instruction. Comments on the system were generally positive.

CONCLUSIONS

While the system has some limitations, a virtual world with a reasonably reliable speech interface has been developed almost entirely from software which is available at minimal cost. Improvements and further testing are considered. Such a system would clearly improve access to virtual reality (VR) technologies for those without the skills or physical ability to use a standard keyboard and mouse. It is an example of both assistive technology (AT) and universal design.

Mandibular advancement splints and continuous positive airway pressure in patients with obstructive sleep apnoea: a randomized cross-over trial

This prospective, randomized, cross-over trial was designed to compare the efficacy of a mandibular advancement splint (MAS) with that of nasal continuous positive airway pressure (nCPAP) in patients with obstructive sleep apnoea (OSA). Twenty-four patients (20 males and four females) with mild to moderate OSA (AHI between 10 and 49 events per hour) were enrolled in the study. Each patient used both MAS and nCPAP, with the initial therapy being allocated at random. Treatment periods lasted for two months with a two-week wash-out interval between. Polysomnography was performed prior to the study and after each clinical intervention. Patient and partner questionnaires were used to assess changes in general health and daytime somnolence. The AHI decreased from 22.2 to 3.1 using nCPAP, and to 8.0 using the MAS (P < 0.001 for both devices) and there was no statistically significant difference between the two treatments. The Epworth Sleepiness Score (ESS) fell from 13.4 to 8.1 with nCPAP, and to 9.2 with MAS (P < 0.001), again with no differences between the use of MAS or nCPAP. The questionnaire data showed an improvement in general health scores (P < 0.001) after both treatments, but daytime sleepiness only improved significantly using nCPAP (P < 0.001). Despite this, 17 out of the 21 subjects who completed both arms of the study preferred the MAS. The splints were well tolerated and their efficacy suggests that the MAS may be a suitable alternative to nCPAP in the management of patients with mild or moderate OSA.

Recording compliance of dental splint use in obstructive sleep apnoea patients by force and temperature modelling

Fibre-optic sensors are used to monitor the force and temperature of dental splints worn by patients suffering from sleep apnoea. Owing to the small size of the sensors, they can be easily embedded within the splint in a way that does not affect the effectiveness of the splint, and, at the same time, are able to indicate whether the splint has been properly worn by the patient. The overall dimensions of the sensor are approximately 0.375 mm thickness, 1 cm length and 3 mm width. The force and temperature sensors are calibrated and found to have sensitivities of better than 0.5 N and 0.1 degrees C, respectively. Trials performed on patients show that the measurement of pressure and temperature is an effective way of monitoring the proper usage of the dental splint by the patients.

Bilateral gynaecomastia as the primary complaint in hyperthyroidism

Association of gynaecomastia with hyperthyroidism is uncommon but has been well documented in the past. Gynaecomastia in a patient with hyperthyroidism rarely presents as a primary complaint. When this occurs, it may present a diagnostic challenge to the clinician. We present the case of a patient who was referred initially to the breast clinic with bilateral gynaecomastia. Hyperthyroidism was subsequently confirmed and treated; gynaecomastia regressed with return to the euthyroid state.

Building a generic architecture for medical information exchange among healthcare providers

Due to the inability to exchange clinical information among hospitals, continuity of care cannot be maintained and a tremendous amount of medical resource has been wasted. This paper describes an architecture that would facilitate exchange of clinical information among heterogeneous hospital information systems. It is dubbed 'Medical Information Exchange Center' or MIEC as part of a six-year Health Information Network Project hosted by the Department of Health. MIEC was designed so that it is innovative yet technically feasible today. It is convenient for authorized users yet secure enough so people can trust and has minimal impact to participated hospitals. Authorized users will be able to access information through two web-based interfaces directed to physician and non-physician users respectively. Hospitals are connected through a virtual private network to exchange patient information and users need to obtain a private key from the certificate authority in order to securely connect to MIEC. A pilot project was conducted to demonstrate the feasibility of this architecture and the problems encountered were discussed.

Induction chemotherapy followed by concurrent chemoradiotherapy in stage III unresectable non-small cell lung cancer

The favourable experience with the combination regimen of vinorelbine, ifosfamide and cisplatin (NIP) in patients with metastatic non-small cell lung cancer (NSCLC) has led to a protocol assessing this regimen as an induction treatment in patients with stage III unresectable NSCLC, followed by thoracic radiotherapy with concurrent daily cisplatin as a radiosensitizer. Two cycles of NIP were administered 21 days apart; each cycle comprised i.v. vinorelbine 25 mg/m2 on days 1 and 8, i.v. ifosfamide 3 g/m2 on day 1 with MESNA as uroprotection, and i.v. cisplatin 50 mg/m2 on day 1. Radical thoracic radiotherapy commenced on day 43 to a total dose of 64 Gy and i.v. cisplatin 6 mg/m2 was given concurrently prior to each fraction of radiation as a sensitiser. Two more cycles of NIP were given to patients who responded favourably to the induction treatment about 2 weeks after completion of radiation. Between July 1995 and July 1997, 44 patients were treated with this protocol. This treatment schedule was generally well tolerated. Grade 3-4 neutropenia occurred in 50% of the patients and neutropenic sepsis was seen in 8. Grade 3-4 oesophagitis was uncommon. Most of the patients were able to complete the induction and concurrent chemoradiotherapy phase. Major response occurred in 75% of the patients with 2 (4.5%) complete responses (CR). A total of 6 patients achieved CR after chemoradiotherapy. At a median follow-up of 35 months, the median overall survival for all patients was 15 months with a 3-year survival rate of 24%. The median overall survival for stage IIIA patients was 19 months with a 3-year survival rate of 39% in contrast to 13 months' median overall survival and only 15% 3-year survival rate for stage IIIB. The NIP regimen results in a high response rate in NSCLC and this treatment programme seems to benefit selected patients with stage III disease.

Endobronchial mass in a patient with Burkholderia pseudomallei infection

INTRODUCTION

Burkholderia pseudomallei infection, the great mimicker of infectious diseases, has protean clinical manifestations.

CLINICAL PICTURE

A 37-year-old man who presented with community-acquired pneumonia affecting the right upper lobe had unremitting fever. Bronchoscopy showed an endobronchial mass in the right upper lobe bronchus.

TREATMENT

Intravenous ceftriaxone and oral erythromycin, with empiric antituberculous treatment added later. This was subsequently switched to intravenous ceftazidime and oral doxycycline after the diagnosis was made.

OUTCOME

There was resolution of the endobronchial mass.

CONCLUSION

This case illustrates a unique and unreported presentation of melioidosis.

Digital photoplethysmography in the diagnosis of suspected lower limb DVT: is it useful?

OBJECTIVE

to determine the role of digital photoplethysmography (D-PPG) in the diagnosis of deep-vein thrombosis (DVT), in comparison to the "gold standard" of either contrast ascending venography (ACV) or colour-flow duplex imaging (CFDI).

METHOD

prospective study of 100 hospital inpatients (103 legs) referred to the X-ray department for ACV or CFDI with clinically suspected lower limb DVT in a district general hospital. Each patient was assessed by either ACV or CFDI, and D-PPG.

RESULTS

thirty-seven limbs were found to have DVT as demonstrated by ACV or CFDI. All patients with a venous refilling time (RT) of greater than 20 s and venous pump (VP) of greater than 35 had a normal ACV or CFDI. Using RT of less than 21 s as the optimal cut-off point, D-PPG achieved a sensitivity of 100%, negative-predictive value of 100%, specificity of 47% and positive-predictive value of 51%. By using VP of less than 36 as the optimal cut-off point, a sensitivity of 100%, a negative-predictive value of 100%, a specificity of 35% and positive-predictive value of 46% were achieved.

CONCLUSIONS

these results validate the use of portable D-PPG as a useful screening tool for the diagnosis of clinically suspected lower limb DVT. A positive test requires further confirmation by one of the "gold standard" methods, whereas a negative test effectively excludes DVT.

Rapid mycobacterial tuberculosis detection in bronchoalveolar lavage samples by polymerase chain reaction in patients with upper lobe infiltrates and bronchiectasis

In areas where tuberculosis is endemic, a positive sputum acid-fast bacilli (AFB) smear is frequently regarded as almost diagnostic of pulmonary tuberculosis (PTB). The main problem arises when the AFB smear is negative. The main aim of this study was to determine the clinical utility of rapid mycobacterial tuberculosis (MTB) detection in bronchoalveolar lavage (BAL) samples by polymerase chain reaction (PCR) in 52 patients who underwent diagnostic bronchoscopy for suspected PTB. These patients had either upper lobe infiltrates (n = 31) or bronchiectasis (n = 21). Mycobacterial culture is usually used as the gold standard of diagnosis. We chose to define active PTB based on positive mycobacterial cultures and/or histological evidence of caseous necrosis and AFB, and/or when there was clinical plus radiological improvement following therapy. We compared AFB smear, respiratory mycobacterial culture, BAL PCR for MTB and clinical active PTB. Four patients who were smear and culture negative had clinical and radiological clearance following anti-tuberculous therapy showing that using mycobacterial culture as a gold standard may have its limitations. When Kappa (a chance-corrected measure of agreement) was calculated for acid-fast bacilli smear and BAL PCR against our definition of active PTB, it was 0.28 (fair agreement) and 0.73 (substantial agreement), respectively. BAL PCR gave a sensitivity, specificity, positive and negative predictive values of 66.7%, 100%, 100% and 88%, respectively, for the group with upper lobe infiltrates. We also demonstrated that BAL for PCR has a good concordance with the final diagnosis of active tuberculosis.

Ethnicity, obstructive sleep apnoea and ischaemic heart disease

We studied the relationship between different ethnic groups, obstructive sleep apnoea (OSA) and ischaemic heart disease. Four hundred and thirty-two inpatients from the medical wards were interviewed. Limited overnight sleep studies were done in 129 of those who had habitual snoring, daytime sleepiness based on an Epworth sleepiness scale of 8 or more, or a large neck size of 40 cm or more. There were 315 Chinese (72.9%), 67 Malays (15.5%), 43 Indians (10%) and 3 from other races (1.4%). The prevalence of OSA was 19.7%, 30% and 12% among the Chinese, Malays and Indians, respectively. The prevalence ratio for OSA was 1.52 in Malays using Chinese patients as the baseline (P = 0.07). The median neck circumference was 37 cm in both racial groups. The median body mass index was 22.7 kg/m2 in Chinese compared to 23.6 kg/m2 in Malays. The median apnoea-hypopnoea index was 22.7, 19.0 and 26.9 events/hour among the Chinese, Malays and Indians, respectively. OSA was independently associated with the prevalence of IHD (adjusted prevalence ratio 1.68; 95% CI: 1.15, 2.46; P = 0.009). The prevalence of ischaemic heart disease (IHD) was 31%, 24% and 28% in Chinese, Malays and Indians, respectively. The prevalence ratio for IHD in Malays compared to Chinese was 0.77. After adjusting for OSA, there was an even greater reduction in the risk of IHD (adjusted prevalence ratio 0.70). This suggests that OSA is a confounder in the relationship between race and ischaemic heart disease.

Aetiology and outcome of severe community-acquired pneumonia in Singapore

The aim of this study was to determine the aetiology and outcome of severe community-acquired pneumonia, and to assess whether the existing guidelines for initial antimicrobial therapy are being applied. The records of 57 consecutive nonimmunocompromised patients admitted to the medical intensive care unit (ICU) between January 1989 and May 1993 with this diagnosis were reviewed. The microbiological data, chest radiographic changes and outcome were analysed. Nine (16%) of the 57 patients had pulmonary tuberculosis. When these patients were excluded from further analysis, a microbiological diagnosis was made in 41 (72%) cases. The most commonest pathogens were Burkholderia pseudomallei (n=10), Klebsiella spp. (n=5) and Staphylococcus aureus (n=5), Mycoplasma pneumoniae (n=4) and Streptococcus pneumoniae (n=2) were less common. This microbiological spectrum was quite different from that in the West, where the incidence of S. pneumoniae was higher. Also, when pulmonary tuberculosis was excluded, the mortality (67%) was much higher than that in other series. This was attributed to the high incidence of unrecognized B. pseudomallei infection, which is associated with a very high mortality in the region under study. In addition to applying published guidelines on severe community-acquired pneumonia, the endemicity of certain organisms such as Mycobacterium tuberculosis and Burkholderia pseudomallei in different geographical regions needs to be considered when choosing initial empirical antimicrobial therapy.

Four cases of developmental foregut cysts

Four patients with developmental foregut cysts were seen in the Singapore General Hospital between 1991 and 1994. Three had bronchogenic cysts while one had features consistent with both enteric and bronchogenic origin. Among those patients with bronchogenic cysts, only one was symptomatic, having presented with cough and dysphagia. Two other patients presented incidentally on chest radiographs done for pre-National Service enlistment while one patient was picked up when a repeat chest radiograph was done following a course of antibiotics. The diagnosis of our first patient with the symptomatic bronchogenic cyst was based on barium swallow and a computerised tomographic scan of the thorax. Two patients were diagnosed on histology following open thoracotomy and surgical resection of the cysts to have a bronchogenic and a cyst of mixed origin as described above respectively. The last patient who underwent video-assisted thoracoscopic surgery with resection of the cyst was confirmed histologically to have a bronchogenic cyst.

Two cases of lower respiratory tract infection due to Chlamydia pneumonia in Singapore

Chlamydia pneumoniae, previously known as Chlamydia psittaci strain TWAR, causes both upper and lower respiratory tract infection. We report the first two cases of culture-positive Chlamydia pneumoniae lower respiratory infection in Singapore. Both patients had underlying fibrosing alveolitis and presented with a history of prolonged productive cough and fever. Chlamydia pneumoniae was isolated from the bronchoalveolar lavage fluid in the absence of other pathogens. The patients responded clinically to three weeks of oral doxycycline therapy. Infection due to Chlamydia pneumoniae should be considered when a patient with community-acquired pneumonia fails to respond to the usual standard antimicrobial therapy.

Nebulized albuterol in acute childhood asthma: comparison of two doses

Thirty-three children and adolescents from 5 to 17 years of age with moderate to severe acute asthma were given nebulized albuterol therapy in either a high (0.30 mg/kg body weight) or standard (0.15 mg/kg) dose administered at three hourly intervals in a randomized double-blind study. The high-dose hourly regimen resulted in significantly greater improvement in the forced expiratory volume in 1 second (FEV1). Furthermore, patients receiving the high dose showed a steady improvement in the FEV1 from the start to the end of the study, whereas FEV1 plateaued after the second dose in the standard-dose group. Although a rise in heart rate and a fall in serum potassium level occurred, neither of these changes nor other side effects were different in the two groups. The high-dose therapy resulted in much higher serum albuterol levels than the standard dose. There was no correlation between the drug levels and side effects or initial and subsequent FEV1. It is concluded that occasional hourly high-dose albuterol therapy should be considered for some pediatric patients with acute asthma of moderate severity, especially those who relapse between doses.

Triiodothyronine uptake measurement in serum by time-resolved fluorescence immunofluorometry

A solid phase competition-type fluoroimmunoassay for triiodothyronine (T3) uptake in serum is described. In the assay, exogenous free T3 binds to the unoccupied binding sites on serum thyroxine binding proteins while the remaining unbound T3 competes with immobilized T3 for binding to a soluble biotinylated anti-T3 monoclonal antibody. The bound biotinylated antibody is quantitated by the addition of streptavidin labeled with the europium chelator 4,7-bis(chlorosulfophenyl-1,10 phenanthroline-2,9-bicarboxylic acid (BCPDA) in the presence of excess europium. The fluorescence signal of the final complex, which is directly proportional to the number of unoccupied binding sites on thyroxine binding proteins, is then measured on the dried solid-phase with a pulsed-laser time-resolved fluorometer. The assay requires a 10 microliters serum sample and a total incubation time of 90 minutes. The coefficients of variation for within-run and between-run assays ranged from 2.0 to 5.7%. Results obtained by the present method compared well with those determined by two commercial radioimmunoassays (r greater than 0.9).

Time-resolved immunofluorometric assay for thyroxine-binding globulin in serum

We describe a new "sandwich"-type immunofluorometric assay for thyroxine-binding globulin (TBG) in serum. The assay involves a solid-phase monoclonal antibody immobilised in white microtiter wells, and a soluble biotinylated monoclonal antibody that reacts with the captured TBG molecules. Addition of streptavidin labeled with the europium chelator, BCPDA (4,7-bis(chlorosulfophenyl)-1,10 phenanthroline-2,9-dicarboxylic acid), and excess europium results in the formation of a highly fluorescent product. The fluorescence signal of the final complex is quantitated on the dried solid-phase with a pulsed-laser time-resolved fluorometer. The assay requires a 151-fold sample pre-dilution and a total incubation time of 90 minutes. It has a broad dynamic range of 0-100 mg/L and a minimum detection limit of 0.4 mg/L. The coefficients of variation for within-run and between-run assays averaged 4.5% and 5.4%, respectively. The mean analytical recovery of TBG added to serum was 103%. Results obtained by this method correlated well with those determined by a commercial radioimmunoassay (r = 0.96, n = 112) and by an immunoradiometric procedure (r = 0.95, n = 131).

High-versus low-dose, frequently administered, nebulized albuterol in children with severe, acute asthma

Thirty-two 5- to 17-year-old children who had severe, acute asthma were randomly assigned to receive either high doses (0.15 mg/kg of body weight per dose) or low doses (0.05 mg/kg of body weight per dose) of nebulized albuterol every 20 minutes for six doses. Compared with the low-dose regimen, the high-dose regimen resulted in significantly greater improvement in forced expiratory volume in 1 second, forced vital capacity, and wheeze score and a lower hospitalization rate. The changes in heart rate, respiratory rate, blood pressure, white blood cell count, and serum potassium concentration did not differ significantly between the groups. The incidence of side effects, which included tremor, hyperactivity, and vomiting, was not significantly different in the two populations. Serum albuterol levels varied widely, but there was no correlation between the levels and the increase in heart rate or other side effects. high-dose, frequently administered, nebulized albuterol appears both safe and effective in treating severe, acute asthma in children.

Pharmacokinetics of inhaled salbutamol in patients with cystic fibrosis versus healthy young adults

We studied the disposition of inhaled salbutamol in adolescents with cystic fibrosis (CF) and compared it with the pharmacokinetics of the drug given by the intravenous and inhaled routes in healthy adults. After inhalation of salbutamol, CF patients had a significantly larger area under the concentration-time curve derived from amounts of drug in the systemic circulation. The differences in serum concentration of salbutamol were not reflected in differences in change of heart rate. We conclude that the rate and extent of pulmonary absorption of inhaled salbutamol in patients with CF differ from those in healthy adults.

Analysis of salbutamol enantiomers in human urine by chiral high-performance liquid chromatography and preliminary studies related to the stereoselective disposition kinetics in man

Enantiomers of salbutamol, extracted from human urine, were successfully separated and quantitated by high-performance liquid chromatography with electrochemical detection. This direct resolution was accomplished using a chiral alpha 1-acid glycoprotein column (EnantioPac) maintained at 0 degrees C and a mobile phase consisting of a 0.1% (v/v) triethylamine in 5.3 mM citrate buffer, pH 7.2. An amperometric detector incorporating a glassy carbon electrode was employed for detection. The between-day coefficients of variation for the determination of R(-)- and S(+)-salbutamol in human urine were 4.1 and 4.7%, respectively, at a drug level of 1.0 microgram/ml. The urinary excretion ratio of the biologically active (-)-isomer to (+)-isomer in one healthy subject who received an intravenous dose of racemic salbutamol (1.0 mg) decreased continuously over a 12-h period. A similar excretion pattern exhibiting a far more extensive distortion in the enantiomeric ratio was found in three subjects dosed with a single 4-mg tablet of racemic salbutamol.

Pharmacokinetics and absolute bioavailability of salbutamol in healthy adult volunteers

Salbutamol was administered to sixteen healthy male volunteers intravenously and by mouth in liquid, tablet, and capsule form using a Latin-Squares design. Pharmacokinetic parameters from intravenous data were similar to previously reported values obtained with oral administration, with a mean terminal half-life of 3.8 h and a mean clearance of 439 ml X min-1 X 1.73 m-2. Peak plasma concentrations of 10-20 ng X ml-1 were obtained 1-3 h following oral administration. The absolute bioavailability of each of the oral preparations was 44%. While statistically significant differences in lag time and time to peak concentration were noted among the various oral preparations, the drug is rapidly absorbed in all three dosage forms and the observed differences are unlikely to be of clinical significance.

Postoperative morphine infusion in newborn infants: assessment of disposition characteristics and safety

Twelve newborn infants were given morphine intravenously for postoperative analgesia. They received a continuous infusion of 6.2 to 40 micrograms/kg/hr for 9 to 105 hours (mean +/- SEM 59.5 +/- 10.2 hours); in four the infusion was preceded by a loading dose of 50 to 100 micrograms/kg. Morphine plasma concentrations correlated with the rate of infusion, but with large variability. There was a tendency for plasma morphine concentrations to decrease in some patients receiving a constant infusion rate, suggesting improvement in morphine clearance rate. Elimination half-life of morphine (13.9 +/- 6.4 hours) was significantly longer than in older children and adults (about 2 hours). Similarly, morphine concentrations in neonates receiving 20 micrograms/kg/hr for 24 hours were three times higher (52 +/- 31 ng/ml) than in older children receiving the same schedule. Two infants who received 32 and 40 micrograms/kg/hr, respectively, developed generalized seizures. Because of the apparently greater sensitivity to morphine and the lower elimination rate in newborn infants, the infused dose should not exceed 15 micrograms/kg/hr.

Determination of salbutamol in human serum by reversed-phase high-performance liquid chromatography with amperometric detection

A simple and sensitive method for the quantitative determination of salbutamol in human serum using reversed-phase ion-pair high-performance liquid chromatography with electrochemical detection is described. The method involves the combined use of Sep-Pak cartridges and ion-pair extraction for sample clean-up, and subsequent separation of salbutamol and the internal standard from interfering compounds on a reversed-phase column. An amperometric detector incorporating a glassy carbon electrode was employed for detection. The inter-assay coefficients of variation at plasma concentrations of 2.0, 6.0 and 20.0 ng/ml were 7.3%, 7.2% and 8.5%, respectively (n = 20). The minimum detection limit was 400 pg/ml from a 0.5-ml sample of serum. The method can be readily utilised for clinical pharmacokinetic studies.