title: Bronchodilator effect on maximal breath-hold time in patients with obstructive lung disease.
abstract: 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 (BHTmaxV EI and BHTmaxV EE, 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 BHTmaxV EI 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, BHTmaxV EE 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.
authors.affiliation: Programa de Pós-Graduação em Ciências Médicas, Serviço de Pneumologia, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Rua Dona Firmina 414, Porto Alegre, RS, Brazil. raqueli@vieci.li
authors.forename: Raqueli Biscayno
authors.initials: RB
authors.lastname: Viecili
authors.forename: Paulo Roberto Stefani
authors.initials: PR
authors.lastname: Sanches
authors.forename: Denise Rossato
authors.initials: DR
authors.lastname: Silva
authors.forename: Danton Pereira da
authors.initials: DP
authors.lastname: Silva
authors.forename: André Frota
authors.initials: AF
authors.lastname: Muller
authors.forename: Sergio Saldanha Menna
authors.initials: SS
authors.lastname: Barreto
mesh_terms: D001993:Bronchodilator Agents / Q000009:adverse effects*; D016022:Case-Control Studies; D005540:Forced Expiratory Flow Rates / Q000187:drug effects; D006801:Humans; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008875:Middle Aged; D011446:Prospective Studies; D012119:Respiration / Q000187:drug effects*; D013997:Time Factors
chemical_list: D001993:Bronchodilator Agents