Evaluation of the Small Airways in Patients with Chronic Obstructive Pulmonary Disease and Alpha-1 Antitrypsin Deficiency

Abstract

Thaís Ferrari da Cruz, Rogerio Rufino, Agnaldo José Lopes, Arnaldo Noronha, Fernando Medeiros Anselmo, Cláudia Henrique da Costa Pneumology Department, Pedro Ernesto Hospital of State University of Rio de Janeiro, Rio de Janeiro, PR, BrazilCorrespondence: Thaís Ferrari da Cruz Av João Gualberto, 253 Ap 241, Cep: 80030-000, Curitiba, PR, Brazil Tel [phone]Email [email protected]: Small airways are not evaluated with traditional pulmonary function tests. The aim of this study was to evaluate the small airways in patients with chronic obstructive pulmonary disease (COPD) with a nitrogen washout test and to verify whether there is a difference between patients with COPD due to smoking and those with COPD due to alpha-1 antitrypsin mutation.Methods: Sixteen patients with mutation in the SERPINA1 gene and 45 patients with no mutation were included in this cross-sectional study. All pulmonary function tests, including the single breath nitrogen washout test, were performed for all patients and alpha-1 antitrypsin dosage was assessed with immunonephelometry.Results: A comparison of patients with COPD due to smoking and those with COPD due to smoking and mutation revealed a significant difference in closure volume (%), which was the poorest in the mutation group. In the group with COPD and mutation, there was an inverse correlation between smoking and closure volume (%). We also verified that similar to forced expiratory volume in the first second (FEV1), the phase III slope (%) and ΔN2 750– 1250 mL (%) could be used to differentiate the severity of airflow limitation.Conclusion: Our results suggest that both variables, phase III slope and the ΔN2 750– 1250 mL (%), could be related to COPD severity. Therefore, alterations at the distribution of the location of the emphysema could alter the results of closer volume and that the nitrogen washout test is more sensitive when compared to traditional pulmonary function test in evaluating COPD patients.Keywords: serine proteinase inhibitors mutation, chronic obstructive pulmonary disease, alpha-1 antitrypsin deficiency, respiratory function tests, nitrogen washout test

Keywords

• serine proteinase inhibitors mutation
• chronic obstructive pulmonary disease
• alpha-1 antitrypsin deficiency
• respiratory function tests
• nitrogen washout test.