Measures of reversibility in response to bronchodilators in chronic airflow obstruction: relation to airway calibre.

Abstract

A study was carried out to examine the independence from starting prebronchodilator FEV1 of four indices commonly used to express airflow (FEV,) reversibility in response to bronchodilators. In 121 patients with chronic airflow obstruction with a mean prebron- chodilator circumstances be a more appropriate index of reversibility.4 This conclusion, however, was based on the results of a single test of response to an anticholinergic agent in a well defined homogeneous group of patients. We have examined the relation of this index and three other commonly used indices of reversibility in response to the prebronchodilator FEV, in a heterogeneous group of patients with chronic airflow obstruction, measuring the response to both an anticholinergic agent, ipratropium bromide, and a /2 agonist, salbutamol. MethodsOne hundred and twenty one outpatients, with a diagnosis of non-asthmatic chronic airflow obstruction and an FEV, below 70% predicted, completed a trial to assess corticosteroid responsiveness.5 Reversibility of the FEV, in response to 500 pg ipratropium bromide and 10 mg salbutamol was measured on different days during the 14 day run in period, before any corticosteroid was administered. Patients were asked to refrain from inhaled bronchodilators for six hours and oral bronchodilators for 24 hours before the laboratory visit. Each drug was given diluted in 2 ml normal saline via an Inspiron Minineb driven by the same air compressor to dryness. FEV, was measured on a dry wedge spirometer (Vitalograph) before the drug was inhaled and 20 minutes (salbutamol) or 25 minutes (ipratropium) after nebulisation had finished. The mean of three technically satisfactory attempts within 10% or 100 ml (whichever was the smaller) was used for subsequent analysis.Reversibility

Effect of salbutamol on dynamic hyperinflation in chronic obstructive pulmonary disease patients

“…(post-FEV1-preFEV1)/predFEV1 × 100) [16], respectively, as recommended by the European Respiratory Society (ERS) consensus statement [17]. Although the ATS criteria indicate a 12% change of baseline FEV1 and an absolute increase of 200 mL as significant response to a bronchodilator [14], ∆FEV1 as per cent of predicted value is less significantly correlated to the initial FEV1 and, thus, does not give an unjustified advantage to low baseline values of FEV1 [18][19][20], being more appropriate on a single crosssectional assessment of reversibility of the bronchial obstruction in COPD patients [21,22].…”

Forced expiratory flows’ contribution to lung function interpretation in schoolchildren

“…Expressing the bronchodilator response in FEV1 relative to the baseline value leads to the tendency of the most obstructed patients to spuriously display the largest bronchodilator response [29,30]. Yet it is the current recommendation [6], the bias being partially overcome by requiring a minimal change of 200 mL; the latter cannot be extended to children, in whom the change in FEV1 is age and height dependent [30].…”

“…Yet it is the current recommendation [6], the bias being partially overcome by requiring a minimal change of 200 mL; the latter cannot be extended to children, in whom the change in FEV1 is age and height dependent [30]. Expressing bronchodilator responsiveness as percentage of predicted has been shown to be independent of baseline FEV1 in asthmatic and non-asthmatic adults with airways obstruction [29,31], or less correlated to baseline FEV1 than percentage of baseline change in children [30]. On the other hand the lower the FEV1, the larger the influence of regression to the mean when expressing the BDR as a percentage of the initial value.…”

Ensaio clínico, aberto, controlado sobre a adição de brometo de ipratrópio ao fenoterol no tratamento da crise de asma em adultos

“…A SpO 2 menor ou igual a 93% implicava a administração de oxigênio, através de cateter nasal, com fluxo de 2L/min, até o fim dos tratamentos. (21,22) .…”