Uma nova abordagem na determinação da resistência das vias aéreas: técnica do interruptor vs. pletismografia

Abstract

Objective: To determine the agreement between interrupter resistance (Rint) and airway resistance (Raw) by plethysmography in order to verify the clinical applicability of the interrupter technique. Methods: The Rint technique was performed with the patients in a sitting position, during exhalation, with a nose clip and cheek support. Plethysmography was carried out in accordance with standard protocols. All measurements were taken prior to and after the administration of an inhaled bronchodilator via a metered dose inhaler with a spacer. Results:The study comprised 99 consecutive patients referred to the Porto Alegre Hospital de Clínicas, located in the city of Porto Alegre, Brazil, for pulmonary function testing. Patient ages ranged from 18 to 82 years, and 52 of the patients were women. In the patients with FEV 1 ≥ 60% of predicted, there was good agreement between the methods (r = 0.8; intraclass correlation coefficient = 0.8). The Rint values were lower than were those of Raw by plethysmography in the patients with more severe disease. ResumoObjetivo: Determinar a concordância da medida da resistência das vias aéreas (RVA) pela técnica interrupter resistance (Rint, resistência do interruptor) com a do método pletismográfico para fins de aplicabilidade clínica. Métodos:A técnica Rint foi realizada com os pacientes em posição sentada, em expiração, utilizando clipe nasal e com suporte das bochechas. O exame pletismográfico foi realizado de acordo com protocolos padronizados. As medidas foram realizadas antes e após a administração inalatória de um broncodilatador via spray dosimetrado com espaçador.

Utilização da técnica de resistência do interruptor na avaliação da resistência das vias aéreas em pacientes com fibrose cística

“…decreased Rint and decreased airway resistance by plethysmography, with no significant difference between the values. (22) One limitation of the present study is that most of the patients presented with mild pulmonary function impairment, meaning that our findings should not be extrapolated to patients with disease that is more severe. This is in accordance with the results reported by Gritti & Barreto, (22) who found the agreement between Rint and airway resistance by plethysmography to be better in patients with mild pulmonary function impairment.…”

“…(22) One limitation of the present study is that most of the patients presented with mild pulmonary function impairment, meaning that our findings should not be extrapolated to patients with disease that is more severe. This is in accordance with the results reported by Gritti & Barreto, (22) who found the agreement between Rint and airway resistance by plethysmography to be better in patients with mild pulmonary function impairment. In addition, one group of authors (23) showed that the Rint technique tends to underestimate airway resistance in obstructed children with asthma and in those with CF, and that this tendency appears to increase in proportion to the severity of airway obstruction.…”

Publicações do Jornal Brasileiro de Pneumologia

“…The number of manuscripts related to pulmonary function increased significantly (by 10%), the publication of studies aimed at updating or comparing techniques for the assessment of respiratory function being of note. ( 2 - 7 ) Another commonly addressed topic was the determination of reference values for the Brazilian and South American populations, especially for the six-minute walk test. ( 8 - 11 ) In addition, the BJP published an international study that proposed reference values for expiratory volumes and flows for the population of Iran.…”