Objective: To identify the role of bronchodilators in the maximal breath-hold time in patients with obstructive lung disease (OLD). Methods: We conducted a case-control study including patients with OLD and a control group. Spirometric tests were performed prior to and after the use of a bronchodilator, as were breath-hold tests, using an electronic microprocessor and a pneumotachograph as a flow transducer. Respiratory flow curves were displayed in real time on a portable computer. The maximal breath-hold times at end-inspiratory volume and at end-expiratory volume (BHTmaxVEI and BHTmaxVEE, respectively) were determined from the acquired signal. Results: A total of 35 patients with OLD and 16 controls were included. Prior to the use of a bronchodilator, the BHTmaxVEI was significantly lower in the OLD group than in the control group (22.27 ± 11.81 s vs. 31.45 ± 15.73 s; p = 0.025), although there was no significant difference between the two groups in terms of the post-bronchodilator values (24.94 ± 12.89 s vs. 31.67 ± 17.53 s). In contrast, BHTmaxVEE values were significantly lower in the OLD group than in the control group, in the pre- and post-bronchodilator tests (16.88 ± 6.58 s vs. 22.09 ± 7.95 s; p = 0.017; and 21.22 ± 9.37 s vs. 28.53 ± 12.46 s; p = 0.024, respectively). Conclusions: Our results provide additional evidence of the clinical usefulness of the breath-hold test in the assessment of pulmonary function and add to the existing knowledge regarding the role of the bronchodilator in this test.

Keywords: Respiratory function tests; Pulmonary disease, chronic obstructive; Bronchodilator agents; Apnea.