Is full inhalation during spirometry inhibited by COPD Pathophysiology?

Extract The diagnosis of chronic obstructive pulmonary disease (COPD) requires confirmation by spirometry; a post-bronchodilator forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) ratio <0.7 indicates the presence of airflow obstruction [1]. The manoeuvre must be performed from total lung capacity (TLC) to ensure accurate results [2]. Patients are coached to inhale fully after completion of the forced exhalation, known as a forced inhaled vital capacity (FIVC). The test is deemed unacceptable if the FIVC is significantly larger than the linked FVC (known as an FIVC-FVC error). The incidence of FIVC-FVC error in COPD patients has not been documented. It has been reported that COPD patients can fail the FIVC-FVC criterion despite coaching and correction of technique [3]. This suggests that both pathophysiological features of COPD and errors in technique may impact the ability to repeatedly reach TLC during the spirometry manoeuvre.