Remote intensive management to improve antiplatelet adherence in acute myocardial infarction: a secondary analysis of the randomized controlled IMMACULATE trial

This study aim to investigate if remote intensive coaching for the first 6 months post-AMI will improve adherence to the twice-a-day antiplatelet medication, ticagrelor. Between July 8, 2015, to March 29, 2019, AMI patients were randomly assigned to remote intensive management (RIM) or standard care (SC). RIM participants underwent 6 months of weekly then two-weekly consultations to review medication side effects and medication adherence coaching by a centralized nurse practitioner team, whereas SC participants received usual cardiologist face-to-face consultations. Adherence to ticagrelor were determined using pill counting and serial platelet reactivity measurements for 12 months. A total of 149 (49.5%) of participants were randomized to RIM and 152 (50.5%) to SC. Adherence to ticagrelor was similar between RIM and SC group at 1 month (94.4 ± 0.7% vs. 93.6±14.7%, p = 0.537), 6 months (91.0±14.6% vs. 90.6±14.8%, p = 0.832) and 12 months (87.4±17.0% vs. 89.8±12.5%, p = 0.688). There was also no significant difference in platelet reactivity between the RIM and SC groups at 1 month (251AU*min [212-328] vs. 267AU*min [208-351], p = 0.399), 6 months (239AU*min [165-308] vs. 235AU*min [171-346], p = 0.610) and 12 months (249AU*min [177-432] vs. 259AU*min [182-360], p = 0.678). Sensitivity analysis did not demonstrate any association of ticagrelor adherence with bleeding events and major adverse cardiovascular events. RIM, comprising 6 months of intensive coaching by nurse practitioners, did not improve adherence to the twice-a-day medication ticagrelor compared with SC among patients with AMI. A gradual decline in ticagrelor adherence over 12 months was observed despite 6 months of intensive coaching.

Remote Postdischarge Treatment of Patients With Acute Myocardial Infarction by Allied Health Care Practitioners vs Standard Care: The IMMACULATE Randomized Clinical Trial

Question

Is remote postdischarge treatment of low-risk patients with acute myocardial infarction by a centralized nurse clinician team under physician supervision feasible and safe?

Findings

In this multicenter randomized clinical trial of 301 participants, there were no significant differences in safety events, medication adjustment, or left ventricular reverse remodeling outcomes in low-risk patients with acute myocardial infarction treated for 6 months after discharge by a centralized nurse practitioner–led telehealth program compared with standard in-person care by a cardiologist.

Meaning

Remote telehealth-enabled allied health care practitioner–led postdischarge management of low-risk patients with acute myocardial infarction is feasible and should be studied in higher-risk acute myocardial infarction cohorts.

Importance

There are few data on remote postdischarge treatment of patients with acute myocardial infarction.

Objective

To compare the safety and efficacy of allied health care practitioner–led remote intensive management (RIM) with cardiologist-led standard care (SC).

Design, Setting, and Participants

This intention-to-treat feasibility trial randomized patients with acute myocardial infarction undergoing early revascularization and with N-terminal–pro-B-type natriuretic peptide concentration more than 300 pg/mL to RIM or SC across 3 hospitals in Singapore from July 8, 2015, to March 29, 2019. RIM participants underwent 6 months of remote consultations that included β-blocker and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACE-I/ARB) dose adjustment by a centralized nurse practitioner team while SC participants were treated face-to-face by their cardiologists.

Main Outcomes and Measures

The primary safety end point was a composite of hypotension, bradycardia, hyperkalemia, or acute kidney injury requiring hospitalization. To assess the efficacy of RIM in dose adjustment of β-blockers and ACE-I/ARBs compared with SC, dose intensity scores were derived by converting comparable doses of different β-blockers and ACE-I/ARBs to a scale from 0 to 5. The primary efficacy end point was the 6-month indexed left ventricular end-systolic volume (LVESV) adjusted for baseline LVESV.

Results

Of 301 participants, 149 (49.5%) were randomized to RIM and 152 (50.5%) to SC. RIM and SC participants had similar mean (SD) age (55.3 [8.5] vs 54.7 [9.1] years), median (interquartile range) N-terminal–pro-B-type natriuretic peptide concentration (807 [524-1360] vs 819 [485-1320] pg/mL), mean (SD) baseline left ventricular ejection fraction (57.4% [11.1%] vs 58.1% [10.3%]), and mean (SD) indexed LVESV (32.4 [14.1] vs 30.6 [11.7] mL/m²); 15 patients [5.9%] had a left ventricular ejection fraction <40%. The primary safety end point occurred in 0 RIM vs 2 SC participants (1.4%) (P = .50). The mean β-blocker and ACE-I/ARB dose intensity score at 6 months was 3.03 vs 2.91 (adjusted mean difference, 0.12 [95% CI, −0.02 to 0.26; P = .10]) and 2.96 vs 2.77 (adjusted mean difference, 0.19 [95% CI, −0.02 to 0.40; P = .07]), respectively. The 6-month indexed LVESV was 28.9 vs 29.7 mL/m² (adjusted mean difference, −0.80 mL/m² [95% CI, −3.20 to 1.60; P = .51]).

Conclusions and Relevance

Among low-risk patients with revascularization after myocardial infarction, RIM by allied health care professionals was feasible and safe. There were no differences in achieved medication doses or indices of left ventricular remodeling. Further studies of RIM in higher-risk cohorts are warranted.

Trial Registration

ClinicalTrials.gov Identifier: NCT02468349

Nutrient availability in the Setiu Wetland Lagoon, Malaysia: trends, possible causes and environmental impacts

The objective of this study was to identify the spatial and temporal variabilities of selected nutrients in the Setiu Wetlands Lagoon (SWL), Malaysia. Water samples were collected quarterly at ten monitoring sites. This study presents results from a 10-year field investigation (2003 to 2010 and 2014 to 2015) of water quality in the SWL. For the spatial pattern, four clusters were identified with hierarchical cluster analysis. Analysis of the temporal trend shows that the high total suspended solid loading in 2010 was due to large-scale land clearing upstream of the SWL. The enrichment of ammonium after 2010 could plausibly be due to land-based aquaculture diffuse discharges. In 2005-2007, expansion of oil palm plantations within the Setiu catchment had doubled the phosphorus concentration in the SWL. The natural and anthropogenic alterations of the lagoon inlets profoundly influenced the spatial distribution patterns of nutrients in the SWL. These results suggest that intense anthropogenic disturbances close to the SWL accounted for the water quality deterioration.

Prognostic Implications of Dual Platelet Reactivity Testing in Acute Coronary Syndrome

Studies on platelet reactivity (PR) testing commonly test PR only after percutaneous coronary intervention (PCI) has been performed. There are few data on pre- and post-PCI testing. Data on simultaneous testing of aspirin and adenosine diphosphate antagonist response are conflicting. We investigated the prognostic value of combined serial assessments of high on-aspirin PR (HASPR) and high on-adenosine diphosphate receptor antagonist PR (HADPR) in patients with acute coronary syndrome (ACS). HASPR and HADPR were assessed in 928 ACS patients before (initial test) and 24 hours after (final test) coronary angiography, with or without revascularization. Patients with HASPR on the initial test, compared with those without, had significantly higher intraprocedural thrombotic events (IPTE) (8.6 vs. 1.2%, p ≤ 0.001) and higher 30-day major adverse cardiovascular and cerebrovascular events (MACCE; 5.2 vs. 2.3%, p = 0.05), but not 12-month MACCE (13.0 vs. 15.1%, p = 0.50). Patients with initial HADPR, compared with those without, had significantly higher IPTE (4.4 vs. 0.9%, p = 0.004), but not 30-day (3.5 vs. 2.3%, p = 0.32) or 12-month MACCE (14.0 vs. 12.5%, p = 0.54). The c-statistic of the Global Registry of Acute Coronary Events (GRACE) score alone, GRACE score + ASPR test and GRACE score + ADPR test for discriminating 30-day MACCE was 0.649, 0.803 and 0.757, respectively. Final ADPR was associated with 30-day MACCE among patients with intermediate-to-high GRACE score (adjusted odds ratio [OR]: 4.50, 95% confidence interval [CI]: 1.14-17.66), but not low GRACE score (adjusted OR: 1.19, 95% CI: 0.13-10.79). In conclusion, both HASPR and HADPR predict ischaemic events in ACS. This predictive utility is time-dependent and risk-dependent.

Determination of trace metals in airborne particulate matter of Kuala Terengganu, Malaysia

Results from the present study in Kuala Terengganu, Malaysia indicated a significant spatial variation but generally the total suspended particulate concentrations (mean = 17.2-148 microg/m(3)) recorded were below the recommended Malaysia guideline for total suspended particulate (mean of 24-h measurement = 260 microg/m(3)). Some of the elemental composition of particulate aerosol is clearly affected by non crustal sources, e.g. vehicular emission sources. Based on correlation and enrichment analyses, the elements could be grouped into two i.e. Pb, Cd and Zn group with sources from vehicular emission (r > 0.6; enrichment factor > 10) and Al, Fe, Mn and Cr group that appears to be of crustal origin (r > 0.6; enrichment factor < 10). It can also be concluded that the mean levels of Pb (1 ng/m(3)), Cd (0.02 ng/m(3)) and Zn (2 ng/m(3)) in the study area are generally lower than other urban areas in Malaysia (Pb < 181 ng/m(3); Cd < 6 ng/m(3); Zn < 192 ng/m(3)).

Cardiac output increases prior to development of pulmonary edema after re-expansion of spontaneous pneumothorax

Pulmonary edema following reexpansion of spontaneous pneumothorax is an uncommon complication. The underlying mechanism of this condition is unclear. We report the hemodynamic characteristics in a series of 7 male patients with spontaneous large (>50%) pneumothoraces of > or = 24 h and correlate the changes with reexpansion pulmonary edema (REPE). A pulmonary artery floatation catheter was inserted and hemodynamic data were obtained before therapeutic chest tube insertion, 1 h after chest tube insertion and the following day. Four (57%) patients developed REPE. There was a tendency for larger pneumothorax to develop REPE. Capillary wedge pressure did not change significantly 1 h after the insertion of chest tube in all our patients. Cardiac output increased significantly in patients who developed REPE compared to those who did not (+ 1.06 l/min vs -0.27 l/min; P = 0.03) 1 h after insertion of chest tube. One patient did not develop pulmonary edema despite having a large (> 80%) pneumothorax. His cardiac output did not rise 1 h after chest tube insertion. REPE is not an uncommon complication following chest tube drainage in patients with large and long-standing pneumothorax. The increase in cardiac output after chest tube insertion may be associated with subsequent development of REPE.

Diffuse panbronchiolitis--a case report

Diffuse panbronchiolitis (DPB) is a chronic progressive obstructive disease of the airways. Of unknown aetiology, it is responsive to macrolide therapy. Although not uncommon among the Japanese, it is rare in other parts of the world. We report a case of DPB in a Chinese patient in Singapore.

The obstructive sleep apnoea syndrome--experience of a referral centre

OBJECTIVE

The aims of this study were: (i) to document the presence and severity of obstructive sleep apnoea (OSA) in patients who complained of heavy snoring and other symptoms suggestive of the OSA syndrome; (ii) to examine the correlation between the clinical and polygraphic findings, and (iii) to document the efficacy and compliance of nasal continuous positive airway pressure (CPAP) among these Asian snorers with OSA.

METHODS

We analysed our clinical and nocturnal polysomnographic data between January 1986 and December 1995 for physician-referred patients who had complained of snoring and other symptoms suggestive of OSA.

RESULTS

A total of 277 diagnostic studies were performed of which 145 (52%) were positive to OSA. For studies performed in the last 2 years (n = 125), 72 of the 125 were positive for OSA. Anthropometric data was not discriminative between the OSA positive snorers and the OSA negative snorers. We found that hypertension and choking were the most significantly related to OSA, conferring a 7 and 4 times relative risk respectively. Nasal CPAP eliminated snoring, apnoeas and oxygen desaturations completely in almost all cases and there were only minor mask-related side effects.

CONCLUSION

OSA may not be uncommon among Asian snorers. Of the major traits for OSA risk among our local population, a history of hypertension and reports of nocturnal choking were the most significantly related. We have also shown that nasal CPAP is safe and effective among our local snorers and should be considered a first-line treatment for OSA.

Effect of oxygen on breathing irregularities during haemodialysis in patients with chronic uraemia

Hypoxaemia and breathing irregularities have been shown to occur during haemodialysis in patients with chronic renal failure. This study examined the role of hypoxia in the genesis of the irregular breathing during haemodialysis. The ventilatory patterns using respiratory inductance plethysmography and arterial blood gases were studied in seven males with chronic renal failure on long-term haemodialysis. The study was carried out before and during dialysis on one day without (D1) and another day with intranasal oxygen at 4 L x min(-1) (D2). On D1, mean (SD) arterial oxygen tension (Pa,O2) fell 1.9 (0.9) kPa (p<0.001) and mean minute ventilation (V'E) fell 1.9 (1.1) L x min(-1) (p<0.01) during dialysis. The arterial carbon dioxide tension (Pa,CO2) did not show a significant decrease (4.7 (0.2) kPa before and 4.6 (0.2) kPa during dialysis). Cumulative number of apnoeas was 64 and the coefficients of variation (COV) of respiratory frequency (fR) and tidal volume (VT) were 29.6 (11.9) and 38.2 (11.9)%, respectively. On D2, mean Pa,O2 remained stable (20.4 (4.1) kPa before, 21.3 (4.1) kPa during dialysis). There was no significant change in mean V'E (6.4 (0.9) L x min(-1) before, 5.5 (0.5) L x min(-1) during dialysis). Pa,CO2 decrease was not significant but the fall was greater (4.8 (0.1) kPa before, 45 (0.5) kPa during dialysis). Cumulative number of apnoeas was 94 and the COVs offR and VT were 35.8 (5.1) and 40.5 (11.3)%, respectively. Oxygen administration did not significantly affect the haemodialysis-induced changes in ventilation and breathing pattern, despite a significant protective effect from the fall in arterial oxygen tension. It was concluded that the fall in arterial oxygen tension is not the main determinant of breathing irregularities during haemodialysis.

Persistent air-leak in spontaneous pneumothorax--clinical course and outcome

Persistent air-leak in patients with spontaneous pneumothorax (SP) is not uncommon and may present a management dilemma in those who are unfit or unwilling for surgery. Video-assisted thoracoscopic surgery (VATS) has been advocated in the management of patients with broncho-pleural fistulae (air-leak persisting beyond 7 days): however the optimum time for surgical intervention remains unclear. We reviewed the records of 130 episodes of SP in 115 patients over a 2-year period to determine clinical course and outcome, particularly with respect to duration of air-leak. There were 90 first episodes and 40 recurrent episodes. Eighty-one episodes (62%) occurred in patients with underlying lung disease (secondary pneumothorax). Initial management consisted of chest-tube drainage in 104 episodes (80%) occurring in 90 patients, percutaneous needle aspiration in five patients (4%) and observation in 21 episodes (16%) in 20 patients. In the group treated with chest-tube drainage, there was spontaneous resolution of air leak and lung re-expansion in 90 episodes (87%). The overall incidence of broncho-pleural fistula was 34.6%. In the primary SP group. 75% of air-leaks ceased by 7 days and 100% by 15 days. In the secondary SP group, 61% of air-leaks resolved by 7 days and 79% by 14 days, after which time resolution of air-leak proceeded at a much slower rate. Five patients underwent surgery while nine patients were discharged with residual pneumothoraces. There were no major complications or mortality. Based on our findings, we advocate surgery for patients with air-leak persisting beyond 14 days, while favouring a conservative approach before this time, as the majority of air-leaks (especially in patients with primary pneumothorax) would resolve by 14 days.

Department audit of inpatient management of asthma

Rising asthma morbidity and mortality worldwide has prompted the recommendation of guidelines for its management. There has also been recent interest in the role of medical audit in assessing the effectiveness of guidelines, and in identifying deficiencies in clinical practice. We disseminated guidelines for the inpatient management of asthma to our department in March 1994, and subsequently performed a criterion-based audit in which we measured our performance in fulfilling various criteria deemed essential for good asthma management. Three periods in time were audited: a five-week period in March/April 1993 before the existence of guidelines (n = 22), the same period in March/April 1994 (n = 27), and the month of August 1994 (n = 17). The introduction of guidelines resulted in definite improvement in history-taking, physical examination, management, review, monitoring and patient fulfillment of pre-discharge criteria. Specific deficiencies identified were underuse of peak flow measurements, which improved after guidelines; and under prescription of oxygen, which persisted despite the guidelines. No difference was noted in terms of the quality outcome indicators of length of hospital stay, complications of procedures, hospital incidents, morbidity, mortality or visits to the A & E. There was, however, an encouraging drop (although not statistically significant) in the one-month readmission rate from 13.6% in 1993, to 7.4% and 5.9% in 1994, after the introduction of guidelines.

Transdiaphragmatic pressure in young adult Singaporean subjects--normal values and a comparison between different respiratory manoeuvres

BACKGROUND

Most published normal values for transdiaphragmatic pressure (Pdi) have been from Caucasian subjects and there is no universal agreement regarding the most appropriate manoeuvre for assessing Pdi.

AIMS

The aims of our study were to obtain normal values and to compare the different manoeuvres used to assess Pdi in normal young Singaporean adults.

METHODS

Twenty-four normal subjects (23 Chinese, one Indian) were studied by measuring Pdi during maximal sniffs from functional residual capacity (sniff Pdi), maximal inspiration to total lung capacity (Pdi TLC) and maximal static inspiratory efforts from residual volume (Pdi PImax).

RESULTS

Mean values +/- SD for sniff Pdi, Pdi TLC and Pdi PImax were 101.8 +/- 31.7, 46.8 +/- 26.4 and 83.5 +/- 35.5 cm H2O respectively. Sniff Pdi was significantly higher than Pdi TLC (p < 0.001) and Pdi PImax (p = 0.005). Pdi PImax was significantly higher than Pdi TLC (p < 0.001). Males had significantly higher values for sniff Pdi (p = 0.026) and Pdi PImax (p = 0.022) than females. There was a significant correlation between the different methods of recording Pdi. Sniff Pdi had the highest values, least between- and within-subject variation and most consistent pattern of respiratory muscle recruitment with the lowest proportion of negative gastric pressure (Pg) values (p < 0.001).

CONCLUSIONS

Therefore, sniff Pdi may be better than Pdi TLC and Pdi PImax in assessing diaphragm function. Also, our subjects seemed to have lower sniff Pdi and Pdi PImax, and higher Pdi TLC compared with Caucasian subjects.

Evaluation of the efficacy of sequential intravenous-oral administration of pefloxacin in community-acquired lower respiratory tract infections in patients with underlying conditions

We studied the efficacy of sequential intravenous-oral pefloxacin therapy in community-acquired lower respiratory tract infection in 24 patients with one or more underlying conditions. Twenty-eight patients were enrolled into the study but only 24 patients were evaluated. There were 16 males and 8 females with a mean age of 66.9 +/- 11.2 years (mean +/- SD, range 46 to 87 years). The underlying conditions present were bronchiectasis, chronic obstructive lung disease and diabetes mellitus. Patients who were older than 70 years but without any underlying condition were also enrolled. All received 4 days of intravenous pefloxacin 400 mg twice a day followed by oral pefloxacin 400 mg twice a day for another 10 days. Assessment of success was based on clinical, microbiological and radiological improvement. Pefloxacin produced 79.2% clinical cure rate. Another 8.3% showed improvement. Pefloxacin was well tolerated. There were few adverse effects and none of the patients required a change of antibiotic. Pefloxacin was an effective and well tolerated treatment for respiratory tract infection and had the advantage of broad in-vitro antibacterial activity, twice daily dosing and sequential availability in an intravenous and oral formulation.

Lung elastic recoil in normal young adult Chinese compared with Caucasians

Chinese people have smaller total lung capacity (TLC) compared with Caucasians of similar age, sex and height. One possible reason would be a higher lung elastic recoil in Chinese. Most published values for lung elastic recoil viz static lung compliance (CLst), shape constant K, and maximal static transpulmonary pressure (PLmax) have been from Caucasian subjects. The aim of our study was to obtain values for lung elastic recoil in normal young adult Chinese subjects. Static expiratory pressure-volume (P-V) curves were studied in 22 healthy Chinese subjects (12 males and 10 females). The P-V curve was fitted using an iterative least mean squares regression on a computer, according to an exponential equation: V = A-Be-KP, where V is lung volume, P is transpulmonary pressure, and A, B and K are constants. Mean values +/- SD for K, CLst and PLmax were 0.12 +/- 0.04, 230 +/- 103 ml.cmH2O-1 and 27.5 +/- 7.5 cmH2O, respectively. The values of CLst and K were similar to that of normal Caucasian subjects, whereas values of PLmax were lower. We attributed the lower PLmax partly to weaker inspiratory muscles in Chinese compared with Caucasians. We conclude that lung elastic recoil in normal young adult Chinese is similar to that of healthy young adult Caucasians. Hence, lung elasticity is unlikely to explain the racial differences in static lung volumes.

Case of occupational asthma due to glue containing cyanoacrylate

Cyanoacrylates are a rare cause of occupational asthma, there being only six cases reported previously. High humidity has been implicated to be protective in the pathogenesis of the asthma. This is a case report of occupational asthma due to cyanoacrylate glue after working three years in a factory manufacturing doors. Diagnosis was made by history, serial peak flow measurements on and off work and specific inhalation challenge which elicited a delayed bronchoconstrictive response. An unusual feature of this case was the positive reaction to cyanoacrylate despite the high ambient humidity in Singapore.

A case of occupational asthma due to barley grain dust

We report a case of occupational asthma due to barley grain dust, species Hordeum Vulgare L, in a 32-year-old storeman of a trading company's department that dealt with packaging of flour, barley and peanuts. He developed immediate symptoms of sneezing, cough and dyspnoea on exposure to barley only. These symptoms showed work relationship. He became asymptomatic after his transfer to another department dealing with sales only. Bronchial provocation testing to the barley confirmed the diagnosis.

A case of late dumping syndrome

We report a case of late dumping syndrome in a 49-year-old lady who had partial gastrectomy for bleeding peptic ulcer 11 years ago. She presented with unexplained syncopal attacks which did not have any apparent relationship to meal or posture. An unusual reaction to oral glucose tolerance test ordered by her gynaecologist who was seeing her for uterine fibroid led to the diagnosis. Late dumping syndrome was confirmed by a repeat oral glucose tolerance test. At the second hour of the test, she developed hypoglycaemic coma with a blood glucose level of 50 mg/dL and a hypocount of 47 mg/dL. She regained full recovery after dextrose infusion which raised the hypocount to 123 mg/dL. The dizzy spells and syncopal attacks disappeared with dietary adjustment.

Congestive heart failure due to a pancreatic pseudocyst

BACKGROUND

Mediastinal extension of pancreatic pseudocysts has caused rare cases of cardiac compression, but to our knowledge, congestive heart disease due to cardiac compression by a pancreatic pseudocyst has never been reported.

SUMMARY

A 48-year-old man presented with dyspnea, swelling of both lower limbs, left-sided chest pain, and colicky, nonradiating epigastric pain. Computed tomography of the abdomen and lower thorax revealed a huge cystic mass directly behind the heart, extending through the esophageal hiatus into the abdomen. The patient subsequently noted dysphagia and epigastric pain and began vomiting after meals. Radiography of the upper gastrointestinal system with barium contrast confirmed that the lower end of the esophagus and the right and lower portions of the stomach were extrinsically compressed. Complete recovery followed surgical removal and internal drainage of a large pancreatic pseudocyst.

CONCLUSIONS

Mediastinal extension of a pancreatic pseudocyst can cause cardiac compression, leading to congestive heart failure.

Pulmonary function in healthy Chinese, Malay and Indian adults in Singapore

Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow rate (PEFR), single-breath diffusion capacity measurements (effective alveolar volume (VA), carbon monoxide transfer factor (DLCO) and transfer coefficient (KCO)) were determined in 452 healthy Singaporean adults (277 males and 175 females) aged 20-70 years. The ratio of Chinese, Malay and Indian subjects was 5:2:3 in both sexes. Age, height and weight in the males were all significantly correlated with FEV1, FVC, DLCO, VA and PEFR. However, for females, only age and height were significantly correlated with the studied lung function parameters. Significant ethnic differences were observed for most of the pulmonary functions (except KCO and PEFR) among the Chinese, Malays and Indians for both males and females. The predicted FEV1 and FVC values (specific age and height) for both sexes were highest among the Chinese followed by the Malays than Indians, in that order. Regression equations, with age and height as independent variables, were derived for males and females in each ethnic group to predict normal pulmonary function for the Singapore Chinese, Malay and Indian populations. The predicted values of various pulmonary function measurements obtained from these regression equations for subjects of specified age (30 years) and height (165 cm for men, 155 cm for women) were compared with those reported in other studies. Differences were observed among the different races.

Epidemiology of sudden unexpected death syndrome among Thai migrant workers in Singapore

A total of 235 cases of sudden unexpected death syndrome (SUDS) among apparently healthy male Thai migrant workers in Singapore were reported between 1982 and 1990. Most of the deaths occurred during sleep and 13% were not sleep-related. The median age at the time of death was 33 years and the median interval between arrival and death was 8 months. These deaths occurred singly and sporadically throughout the year. Post-mortem examination revealed few abnormal findings except for haemorrhagic congestion or oedema of the lungs. There were moderate to severe intra-alveolar haemorrhages with some evidence of myocarditis or pneumonitis. Preliminary findings of serial sections of the hearts indicate evidence of anomalies in the cardiac conduction system. Epidemiological investigations showed that a family history of similar deaths and serological evidence of current or recent infection with Pseudomonas pseudomallei were significantly associated with SUDS. Extensive biochemical and toxicological investigations were inconclusive. There was no evidence of chronic deficiency in thiamine or potassium among the healthy Thai workers living and working in the same conditions as the cases, and no significant abnormalities were detected on electrocardiographic examination. As these migrant workers experienced various psychosocial problems which could stem from maladjustment to an urban environment, separation from the family, burden of debts and long hours of work, stress could be a precipitating factor for SUDS.

The effect of oral midazolam and diazepam on respiration in normal subjects

Benzodiazepine have been shown to suppress ventilatory responses to hyperoxic hypercapnia (HCVR) and isocapnic HVR when taken parenterally. Most patients would, however, prefer to take an oral rather than parenteral preparation but the effect of oral benzodiazepine on these ventilatory responses has not been well studied. We therefore studied the effect of oral midazolam (7.5 mg) and diazepam (5 mg) both given orally on resting ventilation and respiratory drive, as assessed by HCVR and HVR. Flumazenil, a specific benzodiazepine antagonist, was administered intravenously to reverse the effect. A mental alertness-drowsiness index in five grades, from 1 (awake and alert) to 5 (asleep), was used to assess the sedation effect. Six normal male subjects, (aged 31 +/- 1.6 yrs) (mean +/- SD), participated in the study. Mean resting ventilation, and ventilatory response to HCVR and HVR were not significantly altered by these drugs when taken orally. Flumazenil also had not significant effect on HCVR and HVR. However the mental alertness-drowsiness index rose from 1 to 2.83 with oral midazolam and reversed to 1.25 with flumazenil. Similarly, this index increased from 1 to 2.25 after oral diazepam and reversed to 1.42 after flumazenil. In conclusion, we found that even though oral midazolam and diazepam produced a significant sedation effect, which was reversed with flumazenil, the drugs had no effect on ventilation at rest and the ventilatory responses to hypoxia and hypercapnia.

The effect of oral midazolam and diazepam on respiration in normal subjects

Benzodiazepine have been shown to suppress ventilatory responses to hyperoxic hypercapnia (HCVR) and isocapnic HVR when taken parenterally. Most patients would, however, prefer to take an oral rather than parenteral preparation but the effect of oral benzodiazepine on these ventilatory responses has not been well studied. We therefore studied the effect of oral midazolam (7.5 mg) and diazepam (5 mg) both given orally on resting ventilation and respiratory drive, as assessed by HCVR and HVR. Flumazenil, a specific benzodiazepine antagonist, was administered intravenously to reverse the effect. A mental alertness-drowsiness index in five grades, from 1 (awake and alert) to 5 (asleep), was used to assess the sedation effect. Six normal male subjects, (aged 31 +/- 1.6 yrs) (mean +/- SD), participated in the study. Mean resting ventilation, and ventilatory response to HCVR and HVR were not significantly altered by these drugs when taken orally. Flumazenil also had not significant effect on HCVR and HVR. However the mental alertness-drowsiness index rose from 1 to 2.83 with oral midazolam and reversed to 1.25 with flumazenil. Similarly, this index increased from 1 to 2.25 after oral diazepam and reversed to 1.42 after flumazenil. In conclusion, we found that even though oral midazolam and diazepam produced a significant sedation effect, which was reversed with flumazenil, the drugs had no effect on ventilation at rest and the ventilatory responses to hypoxia and hypercapnia.

A case of primary diffuse tracheobronchial amyloidosis treated by laser therapy

We report a case of primary diffuse tracheobronchial amyloidosis in a 72-year-old lady who presented with a long history of recurrent cough, dyspnoea, wheezing, haemoptysis and chest infection. She was treated successfully with three sessions of laser therapy. There were improvements in both clinical symptoms and measurements of airway obstruction. Bronchodilators and oral prednisolone were not required after treatment.

Occupational asthma in Singapore--a review of cases from 1983 to 1990

One of the newer occupational diseases in Singapore is occupational asthma. As on 31 December 1990 there were 35 confirmed cases of occupational asthma in the official statistics on occupational disease. We report in this paper our observations and experience based on these cases. The problem of under-reporting and the importance of early diagnosis are discussed.

Lymphangioleiomyomatosis--treatment with progesterone

Lymphangioleiomyomatosis is a rare devastating disease affecting women mostly of child-bearing age. It presents with spontaneous pneumothorax, chylous effusions, hemoptysis and progressive breathlessness. Most patients die from respiratory failure within 10 years. There are no controlled studies on the efficacy of various treatment regimens. We report our experience with progesterone therapy in three patients. Two failed to respond, one died about 11 years after presentation and another after 5 1/2 years. The third patient has survived 11 years after onset of disease.

The effect of fresh orange juice on bronchial hyperreactivity in asthmatic subjects

We studied 16 mild stable asthmatic subjects to determine if orange juice increases nonspecific bronchial hyperreactivity (NSBH). In 9 subjects, bronchial responsiveness to histamine was assessed before and after water ingestion on the control day, and orange ingestion on a consecutive day. The mean (+/- SD) ratio of log10 PD20 FEV1 after water: log10 PD20 FEV1 before water (1.00 +/- 0.13) was not significantly different from the mean (+/- SD) ratio of log10 PD20 FEV1 after orange: log10 PD20 FEV1 before orange (0.97 +/- 0.12). To avoid the possibility of histamine tachyphylaxis, 7 subjects participated in a second protocol in which histamine PD20 FEV1 was determined on a control day (geometric mean 0.11 mg.) and again two days later, thirty minutes after ingestion of orange juice (geometric mean 0.06 mg). There was no significant difference in the PD20 FEV1 (p = 0.344). Our data show that ingestion of fresh orange juice per se did not heighten NSBH in our subjects. (PD20 FEV1 is the dose of histamine required to produce a twenty percent fall in forced expiratory volume in one second [FEV1]).

Group G streptococcal endocarditis and bacteraemia--a report of 3 cases

Three patients with Group G Streptococcal infection presenting with endocarditis and septicaemia are reported. All had underlying cardiac disease, and one had diabetes mellitus and a colonic carcinoma. Our three patients responded to intravenous crystalline penicillin.

Occupational asthma due to isocyanates in Singapore

Nine cases of occupational asthma due to isocyanates are described. The isocyanates involved included toluene diisocyanate (TDI), diphenyl-methane diisocyanate (MDI) and polyisocyanates. The importance of asking the occupational history in a patient with asthma is illustrated. The importance of early diagnosis and removal from further exposure is also discussed.

Waldenstrom's macroglobulinemia presenting with pleuropulmonary and gastric manifestations

A case of Waldenstrom's macroglobulinemia is reported in which the main clinical presentation was related to pulmonary infiltrations and pleural effusion. Serum protein studies demonstrated the characteristic monoclonal increase in immunoglobulin M (IgMK). Pleural and percutaneous lung biopsies showed dense lymphocytic infiltration. Gastric biopsy also showed focal atypical lymphoid hyperplasia. There was good clinical and radiological response to treatment with chlorambucil and prednisolone.

Sleep apnoea syndrome--a report of 14 cases

Patients with sleep apnoea syndrome suffer considerable morbidity and an increased mortality. We reviewed the characteristics of 14 patients with sleep apnoea syndrome (11 males and 3 females) who were studied since 1986. All were less than or equal to 60 years of age with the majority in their 4th and 5th decade. Obesity was present in 8 patients (57%) and hypertension in 6 (43%). Overnight sleep studies showed that 11 patients had obstructive sleep apnoea, 2 had central and one had predominantly mixed sleep apnoea. Ten patients (71%) had some form of nose and/or throat pathology. Tonsillectomy seemed an effective therapeutic procedure in those with upper airway obstruction due to enlarged tonsils. Four out of 5 patients had significant symptomatic improvement post-tonsillectomy. Nasal continuous positive airway pressure was also effective in alleviating apnoeas and relieving symptoms in 4 other patients who had no obvious upper airway obstruction. A high proportion of our patients had obstructive sleep apnoea due to enlarged tonsils. Tonsillectomy offered a simple and effective therapy for such patients. Nasal continuous positive airway pressure was also effective in the treatment of obstructive sleep apnoea.

The breathing patterns in Chinese and Indian adult males in the supine posture

The breathing patterns in the supine posture during inspiration from functional residual capacity (simulating the "liver palpation" manoeuvre) were studied in two groups of young adult male Chinese and Indians with each group comprising 30 subjects. Both groups were matched for age, height and weight. Although the findings did not reach a statistically significant level, Indian subjects were found to breathe more with their abdomen compared to the Chinese during the manoeuvre. The two groups behaved similarly when they breathed with increasing amplitude from their resting tidal volume to full inspiratory capacity. There was also no difference between the two groups when they performed the total lung capacity manoeuvre.

Carcinoma of the lung with metastases to skeletal muscles

A prominent feature of the natural history of carcinoma of the lung is that it invariably metastasizes to other organs. The well-known sites include lymph nodes, liver, adrenals, bones and brain. Spread is mainly by lymphatic and haematogenous routes, or by direct extension. However, like many other primary malignancies, the spread of carcinoma of the lung to skeletal muscles is rare. This is despite its bulk and abundant blood supply. Why this is so is unknown. A search of the literature revealed only 3 published case reports of carcinoma of the lung spreading to skeletal muscles. In this paper, we report a case of squamous cell carcinoma of the lung with multiple metastases to skeletal muscles.

Occupational asthma due to unheated polyvinylchloride resin dust

Polyvinylchloride (PVC) resins are widely used in industry. Asthma due to the thermal degradation products of PVC are well documented. In this first case of occupational asthma due to unheated PVC resin dust the patient was exposed to PVC resin dust during the mixing of chemicals used for making plastic seals for bottle caps.

Aeromonas endocarditis in a patient with chronic hepatitis-B infection

Aeromonas, a genus of gram-negative bacteria normally found in water and soil, is well established as a pathogen in the animal kingdom. Often considered as a pathogen of low virulence, its role in human infections has recently been recognised. Aeromonas infections in humans range from cellulitis to septicaemia. Endocarditis is rare. We describe here a patient with a chronic liver disease with aeromonas bacteremia and endocarditis.

Mild haemolysis associated with flu-syndrome during daily rifampicin treatment--a case report

We describe a woman with the 'flu' like syndrome and haemolysis whilst on a supervised daily rifampicin regimen for the treatment of pulmonary tuberculosis. Although these are known complications of rifampicin therapy, they often occur when therapy is intermittent or interrupted. Hence the case we describe is unique and is the first of its kind to be reported in Singapore.

Respiratory function in cadmium battery workers--a follow-up study

The lung function status of workers in a cadmium-nickel battery factory was re-examined 3 years after an initial study which showed a mild restrictive effect. During this period, further measures were taken to reduce the cadmium exposure. Of the 44 'original' cadmium-exposed workers, 17 were still exposed to cadmium. Another 13 were transferred to non-cadmium work at least 6 months and 14 left the company at least 1 year before the present study. Blood and urine cadmium concentrations were considerably lower than previously, consistent with the decreased cadmium-in-air levels. The total lung capacity increased both in the workers who were still exposed to cadmium and those who ceased exposure. The latter group also had increased vital capacity and forced expiratory volume in one second. The prevalence of respiratory symptoms decreased particularly in the workers who were no longer exposed to cadmium.

Systemic to pulmonary artery fistulas in Hodgkin's disease

A case of Hodgkin's disease with multiple systemic to pulmonary artery fistulas is described. Despite resolution of the parenchymal infiltrate with combination chemotherapy, the vascular abnormalities persisted. Successful closure of the vascular connections occurred after therapeutic embolization with gel foam and alcohol.

Lung function and respiratory muscle strength after propranolol in thyrotoxicosis

Thirty-five thyrotoxic patients were assessed before treatment, after treatment with propranolol, and after antithyroid drugs. The first group of patients (n = 17) performed the following tests at all three assessment points: forced expiratory volume in the first second (FEV1), vital capacity (VC), functional residual capacity (FRC), residual volume (RV), total lung capacity (TLC), maximal mid-expiratory flow rate (MMFR), diffusing capacity for carbon monoxide (DLCO), and maximum static inspiratory and expiratory mouth pressures (PImax and PEmax). Arterial blood gas analysis was also performed for the first group of patients. No significant changes were seen either after propranolol or after antithyroid drugs in the FRC, RV, TLC, MMFR, DLCO, or blood gases. The remaining 18 patients, group 2, performed only the FEV1, VC, PImax, and PEmax tests at each assessment. The only index of respiratory function that improved significantly after propranolol was PImax (from 46.5 +/- 16.5 to 53.2 +/- 22 cmH2O, p less than 0.01). This suggests that adrenergic excess may play a role in thyrotoxic inspiratory muscle weakness. After antithyroid drugs, PImax, PEmax, FEV1, and VC all increased significantly as expected.

Pulmonary lymphoma or pseudolymphoma: a diagnostic dilemma

The clinical significance of pulmonary pseudolymphoma remains unresolved. We report a case which highlights the lymphoma versus pseudolymphoma dilemma. An elderly lady followed up for more than ten years with a slowly enlarging right lung mass had on biopsy, lymphoid hyperplasia consistent with a lymphoma or pseudolymphoma. Laboratory investigations revealed hyperglobulinemia due to a biclonal gammopathy with elevated serum immunoglobulin M and G fractions. Monoclonal production of immunoglobulin is today considered more indicative of a neoplasia than a hyperplasia.

Early and predominant respiratory muscle involvement in motor neurone disease

We report a 61 year old man with motor neurone disease who presented with dyspnoea and ventilatory failure when the limb and bulbar muscles were relatively spared. This unusual pattern of predominant respiratory muscle involvement persisted throughout the twenty-one month course of his illness.