Epidemiology, clinical characteristics, and treatment outcomes of patients with COVID-19 at Thailand's university-based referral hospital.

BACKGROUND: The epidemiology and outcomes of COVID-19 patients in Thailand are scarce. METHODS: This retrospective cohort study included adult hospitalized patients who were diagnosed with COVID-19 at Siriraj Hospital during February 2020 to April 2020. RESULTS: The prevalence of COVID-19 was 7.5% (107 COVID-19 patients) among 1409 patients who underwent RT-PCR for SARS-CoV-2 detection at our hospital during the outbreak period. Patients with COVID-19 presented with symptoms in 94.4%. Among the 104 patients who were treated with antiviral medications, 78 (75%) received 2-drug regimen (lopinavir/ritonavir or darunavir/ritonavir plus chloroquine or hydroxychloroquine), and 26 (25%) received a 3-drug regimen with favipiravir added to the 2-drug regimen. Disease progression was observed in 18 patients (16.8%). All patients with COVID-19 were discharged alive. CONCLUSIONS: The prevalence of COVID-19 was 7.5% among patients who underwent RT-PCR testing, and 10% among those having risk factors for COVID-19 acquisition. Combination antiviral therapies for COVID-19 patients were well-tolerated and produced a favorable outcome.

Radiographic Features for Predicting Smear-Negative Pulmonary Tuberculosis.

Background: Diagnosis of smear-negative pulmonary tuberculosis (TB) in some circumstances remains a challenge to physicians especially those working in limited-resource settings. Objective: To investigate and examine radiographic characters as a predictor of true diagnosis of pulmonary tuberculosis in patients with negative sputum smears. Material and Method: This retrospective cross-sectional study was conducted in patients with smear-negative pulmonary TB at Siriraj Hospital between January 2013 and June 2014. Patients with previous TB treatment, HIV co-infection, significant pleural effusion, and corticosteroid therapy equivalent to prednisolone greater than 15 mg/day were excluded. Demographic and clinical data were collected and radiographic features were reviewed and classified as active or inactive TB by a consensus of three independent reviewers. Various diagnostic parameters for true prediction of TB, as defined by culture confirmation and/or radiographic improvement, were then examined. Results: There were 122 patients during the study period, 65 (53%) were male, 27 (22%) were asymptomatic, 20 (16%) had extrapulmonary involvement, and eight (7%) had concomitant diabetes mellitus. TB was confirmed in 92 patients (75%), 72 had positive culture and 20 had radiographic improvement. Miliary nodules and cavitary lesions had high specificity (100% and 100%, respectively) and low sensitivity (9.8% and 13%, respectively) for prediction of true TB. Focal interstitial and alveolar opacities had high positive predictive value (79.5 and 85%) and modest accuracy (62.3 and 47.5%). Conclusion: Given that specific radiographic features are uncommon and non-specific features are common in smear-negative pulmonary tuberculosis, clinicians should supplement clinical symptoms, radiological features, and radiological responses with mycobacterium TB culture to verify diagnosis of TB.

Pathological confirmed diagnosis of asbestosis: the first case report in Thailand.

Asbestosis is an occupational lung disease defined as pulmonary fibrosis caused by asbestos. Asbestosis was previously reported in Thailand based on radiologic findings, which demonstrated interstitial lung with calcified pleural plaques, and the patient worked in a fiber cement factory. However there was some doubt about the diagnosis because clinical and radiological findings are nonspecific; there was no data support of asbestos exposure in the patient and no histologic confirmed diagnosis. Histologic diagnosis is most useful when an equivocal of ahistory of asbestos exposure in patients with interstitial lung diseases take place. The authors report a patient presenting with progressive dyspnea for 2 years. She worked in an electric, wire, mesh fan cover factory to check quality of protective wire mesh for 10 years until the factory was closed 6 years ago. This type of factory had never officially reported asbestos use. Her clinical manifestations and radiologic findings are compatible with interstitial lung disease. She subsequently underwent thoracotomy with wedge lung resection. Pathology revealed interstitial fibrosis with honeycombing. Asbestos bodies were found more than 10 per cm2 in the fibrosis. She was diagnosed asbestosis. The patient is suffering from dyspnea, severe hypoxemia and cor pulmonale. The patient is put on waiting lists for heart lung transplantation. The authors thus confirmed that asbestosis exists in Thailand. A policy to protect workers and people who may have risk of asbestos exposure is necessary, since diseases related to asbestos are incurable, but preventable.

Learning environment and resident achievement.

OBJECTIVE: To evaluate the effect of program training atmosphere on the academic performance among internal medicine residents. MATERIAL AND METHOD: Data of satisfaction survey among internal medicine residents in academic year 2012, conducted by the Royal College of Physicians of Thailand, were retrieved. Association between training environment rating scores in three major aspects (program training structure, faculty nurturance, and support system) and board certifying examination scores, were then assessed. RESULTS: There were 12 training centers with 535 residents in that academic year. The mean satisfaction score for second-year residents was 77.1 ± 6.1, and the mean written examination score was 56.4 ± 4.6, with the modest correlation (r = 0.515, p = 0.087). For the third-year residents, the mean satisfaction score was 78.5 ± 6.5 and the mean clinical examination score was 71.1 ± 1.6, with no correlation (r = -0.004, p = 0.991). In the subgroup analysis in second-year residents, program training structure had strongest influence (r = 0.569, p = 0.053), as compared to faculty nurturance (r = 0.425, p = 0.169), andsupport system (r = 0.492, p = 0.104). CONCLUSION: Perception of positive training environment, especially the program training structure, may influence the performance of internal medicine residents in term of knowledge achievement as determined by written examination score. However, it has no effect in terms of clinical skill accomplishments, as determined by clinical examination scores.

Clinical features and outcomes of isoniazid mono-resistant pulmonary tuberculosis.

OBJECTIVE: To determine the characteristics of pulmonary tuberculosis (TB) patients harbored organisms with isoniazid mono-resistant drug susceptibility pattern. MATERIAL AND METHOD: A retrospective review of medical records for all culture-proven adult pulmonary TB patients in Siriraj Hospital between July 2009 and July 2011 was conducted. Demographic data, clinical presentations, and radiological characteristics were recorded and compared between isoniazid mono-resistant and other-resistant groups. Treatment regimens with outcome determination of patients infected with isoniazid mono-resistant strains were also verified. RESULTS: Among 489 patients during the present study period, 28 were infected with isoniazid mono-resistant strain (5.7%). The mean age was 53 +/- 18 years, and 8% of them had a history of previous treatment in the past. When compared with those infected with any other form of resistant strains, isoniazid mono-resistant pulmonary TB patients tended to have less radiographic cavitary lesion (8.3% vs. 26.7%, p = 0.006) but no significant difference was seen in term of demographic data and clinical presentations. All of them who had completed the treatment were cured. No difference in cure rate and relapse rate among patients treated with quinolone or non-quinolone containing regimens. CONCLUSION: Isoniazid mono-resistance shares common clinical features with other resistances pulmonary TB, except for less cavitary lesion from initial chest radiograph. Appropriate drug susceptibility testing with prompt regimen adjustment can lead to a favorable treatment outcome.

Relationship between emphysema quantification and COPD severity.

OBJECTIVE: To determine the association between emphysema extent from high-resolution computed tomography (HRCT) and the physiological derangement in patients with chronic obstructive pulmonary disease (COPD). MATERIAL AND METHOD: A cross-sectional study was undertaken to quantify the emphysema severity in 23 COPD patients by automated HRCT scoring techniques. Correlation with phenotypic characters in term of exercise capacity [Modified Medical Research Council (mMRC) dyspnea scale, and 6-minute walk distance (6MWD)], pulmonary function testing [spirometry (forced expiratory volume in 1 second, FEV1 and forced vital capacity, FVC), and diffusing capacity (DLCO)], were then assessed. RESULTS: Nineteen patients were male and four were female, the mean age was 73 ± 8 years, with the mean FEV1 % predicted of 67.8 ± 25.4. Percentage of inspiratory emphysematous lung volume (%ELVi) had significant negative correlation with %FEV/FVC (r = -0.50, p = 0.016) and DLCO (r = 0.58, p = 0.011). Percentage of expiratory emphysematous lung volumes (%ELVe) also had the same correlation with %FEV/FVC (r = -0.58, p = 0.004) and DLCO (r = 0.48, p = 0.042). In addition, %ELVe also had significant negative correlation with 6MWD (r = 0.50, p = 0.016), but had significant positive correlation with mMRC scale (r = 0.53, p = 0.01). CONCLUSION: Severity of emphysema assessed by HRCT was well correlated with pulmonary function test results and exercise capacity. It can be used as one aspect ofphenotypic characters in patients with COPD,for designing personalize management plan.

Characteristics of culture-negative subclinical pulmonary tuberculosis: a single-center observation.

BACKGROUND: Little is known about culture-negative subclinical pulmonary tuberculosis (TB), and its diagnosis remains challenging. Therefore, this study aimed to identify the characteristics and the extent of disease associated with culture-negative subclinical pulmonary TB. METHODS: This retrospective cohort study was conducted on immunocompetent individuals with subclinical pulmonary TB at a university hospital in Thailand from January 2014 to December 2019. Subclinical pulmonary TB was diagnosed based on the presence of radiographic abnormalities consistent with TB in the absence of TB symptoms. All subjects demonstrated significant improvement or resolution of radiographic abnormalities following the completion of treatment. At least two negative sputum cultures were needed to fulfill the definition of culture-negative pulmonary TB. Data were analyzed using univariate and multiple logistic regression analyses to determine the characteristics of those with culture-negative subclinical pulmonary TB compared to culture-positive ones. RESULTS: Out of the 106 individuals identified with subclinical pulmonary TB, 84 met the criteria for inclusion in the analysis. The study found lower radiographic extent and increasing age were key attributes of culture-negative subclinical pulmonary TB. The odds ratios (95% confidence interval) were 7.18 (1.76 to 29.35) and 1.07 (1.01 to 1.13), respectively. They tend to have lower rates of bilateral involvement in both chest x-ray (8.5% vs. 32.0%, p=0.006) and computed tomography (15.4% vs. 42.9%, p=0.035). However, no other specific radiographic findings were identified. CONCLUSIONS: People with culture-negative subclinical pulmonary TB were likely to have less radiographic -severity, reflecting early disease. Nevertheless, no radiographic patterns, except for unilaterality, were related to culture-negative subclinical pulmonary TB.

Respiratory health effect of persons accidentally expose to high concentration of chlorine gas.

OBJECTIVE: To evaluate the short term and long term respiratory health effects of subjects who accidentally exposed to high concentration of chlorine gas. MATERIAL AND METHOD: There was an accidental leakage of sodium hypochlorite from an industrial factory in Rayong province in June 2010. Medical records of those who developed severe symptoms after exposed to high concentration of chlorine gas were reviewed. Prospective observational study was conducted after hospital discharge by interviewing with respiratory health questionnaires, physical examination, spirometry, methacholine challenge test, and home peak expiratory flow (PEF) monitoring at 2, 5 and 8 months after the event. RESULTS: Among 1,434 persons exposed to chlorine gas, 92 developed severe symptoms required hospital admission and 21 participated in the follow-up study at 2 months there after. Respiratory symptoms were noted in 18 participants. Three most common symptoms were dyspnea (81%), chest tightness (71%), and cough (67%). Obstructive defect from spirometry was identified in 2 participants, one of which also had bronchial hyper responsiveness (BHR) compatible with reactive airway dysfunction syndrome (RADS). Seven participants had abnormal PEF variability. There were 10 and 5 participants left in the follow-up visit at 5 and 8 months respectively. Two participants had persistent obstructive defect with additional two subjects were noticed. Those who had BHR and abnormal PEF variability remained unchanged. CONCLUSION: Acute exposure to high concentration of chlorine gas causes both significant short and long term respiratory health effects. Most of the patients although have gradual improvement of respiratory symptoms, but some symptoms remain persistent. Few patients have lung function impairment lasting for at least 8 months.

Safety and efficacy of noninvasive ventilation for acute respiratory failure in general medical ward: a prospective cohort study.

Background: Noninvasive ventilation (NIV) is recommended for use in patients with acute respiratory failure of various etiologies. However, we do not know whether the use of NIV in general medical wards is safe and effective. This study aimed to evaluate the safety and efficacy of using NIV and factors associated with NIV failure in general medical wards. Methods: A prospective cohort study was conducted in general medical wards of the University Hospital. Adult patients with acute respiratory failure treated with NIV were enrolled. The subjects were managed by a multidisciplinary care team that was well trained in the NIV device. The primary outcome was the rate of NIV failure at 48 hours. Secondary outcomes included hospital mortality and factors associated with NIV failure. Results: A total of 86 patients were enrolled. The mean age was 70±17 years old. The Acute Physiology and Chronic Health Evaluation (APACHE) III and the Sequential Organ Failure Assessment (SOFA) scores were 56±17 and 4±3, respectively. The most common indication of NIV use was cardiogenic pulmonary edema (34.9%). The rate of NIV failure at 48 hours and hospital mortality were 20.9% and 12.8%, respectively. The SOFA score was associated with failure of NIV at 48 hours [odds ratio (OR) 1.48, 95% confidence interval (CI): 1.16-1.89; P=0.002]. Conclusions: NIV was safe and effective on general medical wards. Cardiogenic pulmonary edema was the most common indication for the application of NIV. The SOFA score was associated with the failure of NIV at 48 hours.

Contribution of examiner subjectivity and patient heterogeneity on long case examination.

OBJECTIVE: To evaluate the effect of examiner subjectivity and heterogeneity among the cases on scores from the Royal College of Physicians (RCPT) long case examination. MATERIAL AND METHOD: Data from internal medicine candidates who performed clinical part of RCPT board certifying examination in academic year 2008 were collected. For each candidate, scores from pair of examiners for each of the long case was stratified based on disease category according to the course syllabus into 3 groups; very common, common and uncommon diseases. The scores also categorized according to difficulty level subjectively and rated by the examiners into 3 levels; easy, moderate and difficult. Mean scores in each group of encounters were compared using ANOVA. RESULTS: There were 21 examination centers involved with 1,840 number of encounters by 232 candidates. Among 437 patients that have been used for the long case, common scenarios (27.6% of the total) were cirrhosis, hyperthyroidism, cerebral thrombosis, bronchogenic carcinoma, rheumatic heart disease and thalassemia. Mean and SD of scores from the very common, common and uncommon diseases were 75.5 +/- 11.6, 75.6 +/- 10.6 and 74.7 +/- 11.3 respectively, with no statistical significant difference between the groups. Mean and SD of scores from the easy, moderate and difficult cases were 76.1 +/- 10.5, 74.8 +/- 11.0, 75.5 +/- 10.9 respectively. The moderate group has the lowest score with a statistical significant difference from other groups (p = 0.042). CONCLUSION: In current RCPT long case examination, difficulty of the case appears to contribute to variation in scores derived from the examiners. Measures for score adjustment and examiner calibration should be implemented in the future.

Are two sputum samples enough for diagnosing pulmonary tuberculosis.

OBJECTIVE: To determine the optimum number of sputum specimens for smear and culture in the diagnosis of pulmonary tuberculosis. MATERIAL AND METHOD: A retrospective study was conducted in culture-positive pulmonary tuberculosis patients at Siriraj Hospital during April 2009 to October 2010. Number of sputum specimens and microbiological results were retrieved from the microbiologic laboratory. Positive yield and incremental yield of each sputum specimen were calculated. RESULTS: There were 401 patients during the study period, 153 (38.2%) had positive smear for acid-fast bacilli. Overall diagnostic yields of solid culture media and liquid culture media, were 72.1% and 95.3% respectively. Incremental of overall diagnostic yield from 1 to 2 and 2 to 3 sputum specimens were 8% and 6% respectively. CONCLUSION: In place where a routinely combined smear and culture for every sputum sample submitted to the microbiologic laboratory, two specimens are sufficient for the diagnosis in nearly all pulmonary tuberculosis patients.

Severe obesity is a risk factor for severe obstructive sleep apnea in obese children.

OBJECTIVE: To determine the association between degree of obesity and severity of OSA in Thai children MATERIAL AND METHOD: The present retrospective study recruited obese children aged 3 to 15 years who had habitual snoring and underwent polysomnography (PSG) between January 2009 and June 2010. Obesity was defined as percentage of ideal weight for height (%W/H) > or = 120 and was classified as mild (%W/H of 120-139), moderate (140-159), severe (160-199) and morbid (> or = 200). OSA was classified as severe (AHI > or = 10) and non-severe (AHI < 10). RESULTS: Of 73 obese children, the mean age was 9.92 +/- 3.42 years of which 60.3% were boys. The mean +/- SD of BMI was 28.38 +/- 5.99 kg/m2 and %W/H +/- SD was 162.63 +/- 26 26. Gender age, height, weight and BMI were not significantly different between severe and non-severe OSA groups. However, the %W/H of the severe OSA group (171.38% +/- 29.54%) was significantly greater than the non-severe group (157.19% +/- 22.68%) (p = 0.02). Severe to morbid obesity (OR 2.80, 95% CI 1.06-7.42; p = 0.038) and enlarged tonsils at least 3+ (OR 3.28, 95% CI 1.22-8.81; p = 0.018) were the risk factors for severe OSA. CONCLUSION: Severe to morbid obesity was a predicting factor for severe OSA. These results suggested that severely obese children with snoring should have early recognition for severe OSA, which is highly contributing to multiple sequalae.

Can we predict final outcome of internal medicine residents with in-training evaluation.

OBJECTIVE: To assess the predictive value of in-training evaluation for determining future success in the internal medicine board certifying examination. MATERIAL AND METHOD: Ninety-seven internal medicine residents from Faculty of Medicine Siriraj Hospital who undertake the Thai Board examination during the academic year 2006-2008 were enrolled. Correlation between the scores during internal medicine rotation and final scores in board examination were then examined. RESULTS: Significant positive linear correlation was found between scores from both written and clinical parts of board certifying examination and scores from the first-year summative written and clinical examinations and also the second-year formative written examination (r = 0.43-0.68, p < 0.001). Monthly evaluation by attending staffs was less well correlated (r = 0.29-0.36) and the evaluation by nurses or medical students demonstrated inverse relationship (r = -0.2, p = 0.27 and r = -0.13, p = 0.48). CONCLUSION: Some methods of in-training evaluation can predict successful outcome of board certifying examination. Multisource assessments cannot well extrapolate some aspects of professional competences and qualities.

Population pharmacokinetic modeling of the association between 63396C->T pregnane X receptor polymorphism and unboosted atazanavir clearance.

Atazanavir (ATV) plasma concentrations are influenced by CYP3A4 and ABCB1, which are regulated by the pregnane X receptor (PXR; NR1I2). PXR expression is correlated with CYP3A4 in liver in the absence of enzyme inducers. The PXR single nucleotide polymorphism (SNP) 63396C→T (rs2472677) alters PXR expression and CYP3A4 activity in vitro, and we previously showed an association of this polymorphism with unboosted ATV plasma concentrations. The aim of this study was to develop a population pharmacokinetic analysis to quantify the impact of 63396C→T and diurnal variation on ATV clearance. A population analysis was performed with 323 plasma samples from 182 randomly selected patients receiving unboosted ATV. Two hundred fifty-nine of the blood samples were collected at random time points, and 11 patients had a full concentration-time profile at steady state. Nonlinear mixed effects modeling was applied to explore the effects of PXR 63396C→T, patient demographics, and diurnal variation. A one-compartment model with first-order absorption and lag time best described the data. Population clearance was 19.7 liters/h with interpatient variability or coefficient of variation (CV) of 21.5%. Homozygosity for the T allele for PXR 63396 was associated with a 17.0% higher clearance that was statistically significant. Evening dosing was associated with 34% higher bioavailability than morning dosing. Patient demographic factors had no effect on ATV clearance. These data show an association of PXR 63396C→T and diurnal variation on unboosted ATV clearance. The association is likely to be mediated through an effect on hepatic PXR expression and therefore expression of its target genes (e.g., CYP3A4, SLCO1B1, and ABCB1), which are known to be involved in ATV clearance.

Reliability and validity of long case and short case in internal medicine board certification examination.

OBJECTIVE: To be certified for the Thai Board of Internal Medicine, each candidate must pass both written and clinical examinations performed in different academic years. The present study aimed to assess the reliability and validity of the long case and short case which contribute major fractions in the clinical part of board certifying examination. MATERIAL AND METHOD: Data from 585 internal medicine residents entering a first-attempt clinical part in board certifying examination during the academic year 2005-2007 were collected. Inter-rater reliability and construct validity of the long case and short case were then examined. RESULTS: Good to excellent intraclass correlation (ICC) of scores from different examiners was demonstrated (ICC between 0.71 and 0.97) and the variation ranged from 15.3 to 27.3%. For different occasions of examination, class normalized gain was between -0.7 and -9.0% and negative individual normalized gain was observed in 45.6% to 48.2% of the candidates. CONCLUSION: Acceptable inter-rater reliability was demonstrated in long case and short case in clinical examination for the Thai Board of Internal Medicine. But construct validity for this type of clinical assessment was not established.

Venovenous extracorporeal membrane oxygenation versus conventional mechanical ventilation to treat refractory hypoxemia in patients with acute respiratory distress syndrome: a retrospective cohort study.

OBJECTIVE: To compare the treatment outcome of venovenous extracorporeal membrane oxygenation (VV-ECMO) versus mechanical ventilation in hypoxemic patients with acute respiratory distress syndrome (ARDS) at a referral center that started offering VV-EMCO support in 2010. METHODS: This retrospective cohort study enrolled adults with severe ARDS (PaO2/FiO2 ratio of <100 with FiO2 of ≥90 or Murray score of ≥3) who were admitted to the intensive care unit of Siriraj Hospital (Bangkok, Thailand) from January 2010 to December 2018. All patients were treated using a low tidal volume (TV) and optimal positive end-expiratory pressure. The primary outcome was hospital mortality. RESULTS: Sixty-four patients (ECMO, n = 30; mechanical ventilation, n = 34) were recruited. There was no significant difference in the baseline PaO2/FiO2 ratio (67.2 ± 25.7 vs. 76.6 ± 16.0), FiO2 (97 ± 9 vs. 94 ± 8), or Murray score (3.4 ± 0.5 vs. 3.3 ± 0.5) between the ECMO and mechanical ventilation groups. The hospital mortality rate was also not significantly different between the two groups (ECMO, 20/30 [66.7%] vs. mechanical ventilation, 24/34 [70.6%]). Patients who underwent ECMO were ventilated with a significantly lower TV than patients who underwent mechanical ventilation (3.8 ± 1.8 vs. 6.6 ± 1.4 mL, respectively). CONCLUSION: Although VV-ECMO promoted lower-TV ventilation, it did not improve the in-hospital mortality rate. Trial registration: www.clinicaltrials.gov (NCT04031794).

The evolution of diaphragm activity and function determined by ultrasound during spontaneous breathing trials.

PURPOSE: Rapid shallow breathing index (RSBI) is a commonly used index for predicting the outcome of spontaneous breathing trial (SBT). Ultrasound is a non-invasive technique for assessing diaphragm activity and function. This study aimed to investigate changes in diaphragm activity during SBT, and to compare diaphragm function between patients with and without SBT success. MATERIALS AND METHODS: Forty-five patients undergoing SBT were enrolled. Thickening fraction of the diaphragm was assessed during tidal breathing (TFditidal), and RSBI was measured during 30 min of SBT. Diaphragm function measured by maximum TFdi (TFdimax) and diaphragmatic excursion (DEmax) was also evaluated. RESULTS: TFditidal and RSBI significantly increased during SBT (TFditidal0vs. TFditidal30 = 29.8 ±â€¯13.8 vs. 37.4 ±â€¯13.0%; p < .001, and RSBI0vs. RSBI30 = 64.8 ±â€¯25.9 vs.70.8 ±â€¯29.1 breaths/min/L; p = .034). In SBT failure (n = 13), there was no significant difference in TFditidal compared to SBT success, except at the beginning of the trial (p = .043); however, RSBI significantly increased throughout SBT. No differences in TFdimax or DEmax were observed between groups. CONCLUSIONS: Patient inspiratory efforts significantly increased during SBT. TFditidal measured by diaphragm ultrasound could not distinguish between patients with SBT success and failure. RSBI was significantly higher during SBT in patients with SBT failure.

Factors determining the severity of pulmonary function impairment in silicotic patients.

OBJECTIVE: Silicosis is the most common occupational lung disease in Thailand. Determinants of pulmonary function impairment in Thai silicotic patients have not been mentioned before. MATERIAL AND METHOD: The present study was conducted in silicotic patients who attended the Siriraj Occupational Lung Clinic in the year 2006. Patients were classified according to the forced expiratory volume in one second (FEV1) into the severe impairment group (< 50% predicted) and the non-severe group (FEV1 > 50% predicted) which includes normal FEV1. Comparison between the two groups in terms of demographic characteristics, smoking history, history of pulmonary tuberculosis, and radiographic features were assessed. RESULTS: Thirty-four patients of which 24 were female (70.6%) had an overall mean age of 53.7 years. Seven patients (20.6%) had severe impairment, four were female, three were smokers, and two had a history of pulmonary tuberculosis. All of the severe impairment patients had nodule profusion in category 2 and had large opacity. Only the presence of large opacity was significantly associated with the severity of pulmonary function impairment (p = 0.002). CONCLUSION: Only the presence of large opacity in a chest radiograph can determine the severity of pulmonary function impairment in Thai silicotic patients.

Comparison of clinical and polysomnographic characteristics of non-obese and obese patients with obstructive sleep apnea.

OBJECTIVE: To compare the clinical features, anthropometric indices, and polysomnographic data between different body mass index (BMI) subgroups of obstructive sleep apnea (OSA) patients. MATERIAL AND METHOD: The authors reviewed the data from OSA patients in Siriraj Sleep Clinic from April 2005 to September 2006. Objective measurement for sleepiness (Epworth Sleepiness Scale, ESS), anthropometric measurements [body mass index (BMI), neck circumference, thyromental distance, Mallampati S score, and occlusion pattern] and polysomnographic recordings [apnea/hypopnea index (AHI) during REM and NREM periods, respiratory arousal index, periodic leg movement index, minimal oxygen saturation, total sleep time with oxygen saturation <90%, and desaturation index] were collected. The patients were stratified into the non-obese group and obese group if their BMI was <27 or > or =27 kg/m2 respectively. RESULTS: Of the total 158 patients, 71 were non-obese and 87 were obese, no difference in mean age and sex was observed, but more patients with hypertension and coronary artery disease were noted in the obese group. Mean ESS was not different between the 2 groups. In anthropometric measurements, the obese group had statistically significant large neck circumference (41.6 +/- 3.5 cm vs. 37.0 +/- 2.9 cm, p<0.001), but the nonobese group had a shorter thyromental distance (56.4 +/- 11.7 mm vs. 61.4 +/- 11.2 mm, p=0.006), with no significant difference in Mallampatis score and occlusion pattern. In polysomnographic data, the obese group had statistical significantly more severity of various indices except for AHI during the REM period and the periodic limb movement index. CONCLUSION: Non-obese obstructive sleep apnea patients have more bony structural change than the obese ones as demonstrated by shorter thyromental distance. But degree of abnormalities during sleep was less severe in nearly all aspects.