Paradoxical bronchospasm may be unrecognized in patients with COPD or bronchial asthma, according to a review of spirometry test results from US military veterans.

The study retrospectively analysed results of 1150 pre- and post-bronchodilator spirometry tests performed between 2017 and 2020 in patients with COPD or asthma. For the purpose of the study, paradoxical bronchospasm was defined as a decrease of at least 12%- and 200-mL in forced expiratory volume in one second (FEV1) and/or forced vital capacity (FVC) from baseline after albuterol inhalation (four puffs).

Out of the 1150 results reviewed, 18 were identified with post bronchodilator paradoxical bronchospasm. Twelve of these reports were of patients who had COPD, 4 were of patients with asthma, while two had asthma and COPD. Seventeen of the 18 patients had a smoking history (13 were previous smokers and 4 were current smokers), while only one was a non-smoker. None of the reports stated post-bronchodilator paradoxical bronchospasm in the results.

Eight participants were found to have emphysema on chest CT, while three patients showed bronchial wall thickening. Four asthmatic patients had a chest x-ray done, which showed no significant findings.

All the study participants were treated with inhaled b2-adrenergic agonists and five were treated with cardioselective b-1 blockers. Eleven patients had obstructive sleep apnea and 10 were treated for gastroesophageal reflux disease (GERD).

A decrease in FEV1 of 22±8% and 367±167 mL from baseline was noted in 12 participants after inhalation of albuterol, while there was a significant decrease in FVC from baseline (14±3% and 448±179 mL) in six participants. No respiratory symptoms, during or after spirometry testing, were reported by the study subjects.

These study findings were presented at the recently concluded Chest 2021, the virtual annual meeting of the American College of Chest Physicians.

Paradoxical bronchospasm is the sudden onset of bronchoconstriction after administration of short-acting b2-agonists such as albuterol. It is a rare and potentially life-threatening adverse effect as it may result in respiratory distress or acute respiratory failure. Hence, its timely recognition is crucial.

This study demonstrates that even though paradoxical bronchospasm occurs rarely during spirometry, it is not recognized nor reported in test results. Patients who developed paradoxical bronchospasm in this study had GERD or obstructive sleep apnea; most of them had a history of smoking, either current or previous. It further highlights the need for greater awareness about paradoxical bronchospasm so that all patients, including the at-risk patients, can be monitored to prevent adverse outcomes.

Reference

1. Kaul M, et al. Paradoxical bronchospasm in US military veterans with COPD or asthma at a tertiary VA Medical Center. Chest. 2021 October.160(4 Suppl): A1790. DOI https://doi.org/10.1016/j.chest.2021.07.1625.