Correlation between impulse oscillometry with bronchodilator reversibility in asthmatic population in a tertiary referral centre.

INTRODUCTION: Spirometry is considered as a 'gold standard' for diagnosis of asthma. Impulse oscillometry (IOS) is an alternative diagnostic tool which requires less cooperation by the participants. We performed a study to determine the correlation of IOS with bronchodilator reversibility from spirometry in asthmatic participants. We studied the correlation between forced expiratory flow (FEF25%-75%) and differences between the resistance at 5Hz and 20Hz (R5-R20) in small airway disease (SAD) and the proportion of SAD diagnosed using IOS. MATERIALS AND METHODS: This was a cross-sectional study involving 82 asthmatic participants in Hospital Canselor Tuanku Muhriz (HCTM), Universiti Kebangsaan Malaysia (UKM) conducted between December 2020 till January 2022. Participants performed pre- and post-bronchodilator IOS and spirometry within the same day. Correlation between spirometry and IOS parameters and FEF25%-75% with IOS were determined and analysed. RESULTS: The change of forced expiratory volume in 1 second (FEV1) was statistically correlated with a change of R5 in IOS. A decrement of 14.5% in R5 can be correlated with positive bronchodilator response (BDR) with a sensitivity of 63.9% and specificity of 60.9%, p=0.007. Pre-bronchodilator FEF25%-75% correlated with all parameters of SAD in IOS, e.g., R5-R20, reactance at 5Hz (X5) and area of reactance (AX), p < 0.05. IOS detection for SAD is higher compared to FEF25%-75% in the BDR negative group (91.3% vs 58.7%). CONCLUSION: IOS detected both bronchodilator reversibility and SAD hence can be considered as an alternative tool to spirometry for diagnosis of asthma in adults. IOS detected SAD more than FEF25%-75%, especially in BDR-negative group.

Lung computed tomography patterns of a cluster of asymptomatic young males with COVID-19 admitted to a teaching hospital in Kuala Lumpur.

BACKGROUND AND OBJECTIVE: Coronavirus Disease 2019 (COVID- 19) was first reported in Malaysia in March 2020. We describe here the clinical characteristics and computed tomography (CT) patterns in asymptomatic young patients who had laboratory-confirmed COVID-19. METHODS: This is a retrospective observational study where 25 male in-patients with laboratory-confirmed COVID-19 in Hospital Canselor Tuanku Muhriz. Demographics, clinical data and CT images of these patients were reviewed by 2 senior radiologists. RESULTS: In total there were 25 patients (all males; mean age [±SD], 21.64±2.40 years; range, 18-27 years). Patients with abnormal chest CT showed a relatively low normal absolute lymphocytes count (median: 2.2 x 109/L) and absolute monocyte count (median: 0.5 x 109/L). Lactate dehydrogenase was elevated in 5 (20%) of the patients. The procalcitonin level was normal while elevated levels of alanine aminotransferase, total bilirubin, platelet and C-reactive protein were common. Baseline chest CT showed abnormalities in 6 patients. The distribution of the lesions were; upper lobe 3 (12%) lower lobe 3 (12%) with peripheral distribution 4 (16%). Of the 25 patients included, 4 (16%) had ground glass opacification (GGO), 1 (4%) had a small peripheral subpleural nodule, and 1 (4%) had a dense solitary granuloma. Four patients had typical CT features of COVID-19. CONCLUSION: We found that the CT imaging showed peripheral GGO in our patients. They remained clinically stable with no deterioration of their respiratory symptoms suggesting stability in lung involvement. We postulate that rapid changes in CT imaging may not be present in young, asymptomatic, non-smoking COVID-19 patients. Thus the use of CT thoraxfor early diagnosis may be reserved for patients in the older agegroups, and not in younger patients.