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.

Predictive risk factors for pneumothorax following fluoroscopic-guided transbronchial lung biopsy.

INTRODUCTION: Fluoroscopic-guided transbronchial lung biopsy (FG-TBLB) is routinely performed via bronchoscopy to diagnose focal peripheral lesions and diffuse lung disease. Identifying the risk factors of FG-TBLB-related pneumothorax can assist the operator in taking pre-emptive measures to prepare for this potential complication. MATERIALS AND METHODS: We retrospectively analysed data from 157 patients who underwent FG-TBLB, with the primary outcome being procedure-related pneumothorax. We assessed several risk factors for pneumothorax following FG-TBLB: patient characteristics, location of biopsy, number of biopsies and computed tomography pattern. Univariate and multivariate logistic regression analyses were performed. RESULTS: One-hundred fifty-seven patients were included [mean (SD) age 57.9 (16.2) years; 60.5% male]. The most common location for FG-TBLB was the right upper lobe (n=45, 28.7%). The mean (SD) number of biopsy samples was 6.7 (2.1). Radiographic evidence of pneumothorax was reported in 12 (7.6%) patients, with 11 of those requiring intercostal chest tube intervention (mean air leak time: 5.7 days and 1 had persistent air leak requiring autologous blood patch pleurodesis. None experienced pneumothorax recurrence. Female gender and upper lobe location of the biopsy were identified as predisposing factors for pneumothorax. In the multivariable analysis, upper lobe biopsies were associated with a higher risk of pneumothorax (OR 0.120; 95% CI 0.015-0.963; p = 0.046). CONCLUSION: The overall rate of pneumothorax is low. We recognise the increased risk of pneumothorax associated with upper lobe biopsy. These findings suggest that clinicians should exercise caution when performing FGTBLB in this region and consider alternative biopsy locations whenever feasible. We suggest adequate planning and preparation should be implemented to minimise the risk of pneumothorax following FG-TBLB.