Safety aspects of local endobronchial allergen challenge in asthmatic patients.

Abstract

Local endobronchial allergen challenge is being increasingly used to investigate the role of allergic inflammation in asthma. However, little information is available about the safety of this procedure and the changes induced in airway physiology. BAL and biopsy were performed at 10 min and at 4 to 6 h, or 24 h after segmental allergen challenge in 49 patients with atopic asthma. Two hours after challenge, FEV1 was reduced from 97.6 +/- 13.9 (mean +/- SD) to 83.4 +/- 21.7% predicted. FEV1 remained reduced at 4 to 6 h (87.7 +/- 20.4%), but it had nearly returned to baseline by 24 h (93.2 +/- 14.0%). When endobronchial challenge was combined with BAL and biopsy, the initial fall in FEV1 was slightly greater (from 101.8 +/- 14.2 to 78.5 +/- 13.6%). Bronchial responsiveness to methacholine was measured in 10 subjects, and it showed a twofold increase 24 h after local challenge and lavage. Significant changes in FEV1 and methacholine PC20 were still detectable 72 h after challenge. Widespread wheezing occurred in 29% of the subjects, but none of the them had to be admitted to hospital. We conclude that local endobronchial allergen challenge, although producing measurable changes in airway physiology, is in general well tolerated and is an acceptable method to investigate airway pathophysiologic processes in patients with mild to moderate asthma.

The course of allergen-induced leukocyte infiltration in human and experimental asthma

“…1 Studies using the same models as in the current study reported a maximum of late-phase bronchoconstriction approximately 6 hours after allergen exposure. 3,13 This discrepancy does not support the concept that bronchoconstriction and eosinophil recruitment are directly related. 3,26 Indeed, there is evidence to question this concept.…”

“…11,12 Segmental allergen challenge has been widely used because of its safety and the possibility to compare BAL fluid and biopsy specimens from challenged and unchallenged segments intraindividually. 13 Most protocols include 2 bronchoscopies. The first bronchoscopy is performed during the early asthmatic response (5-10 minutes after challenge).…”

Airway endothelin levels in asthma: influence of endobronchial allergen challenge and maintenance corticosteroid therapy

“…Fibreoptic bronchoscopy, endobronchial allergen challenge and BAL were performed in accordance with our published procedure [23], conforming to current National Heart, Lung and Blood Institute (NHLBI) guidelines [24]. Premedication consisted of nebulized salbutamol 5 mg and ipratropium bromide 0.5 mg, intravenous atropine 0.6 mg, and intravenous midazolam as required (median 6.5 (range 0-8) mg).…”

Investigative Bronchoprovocation and Bronchoscopy in Airway Diseases

“…Previous guidelines have suggested that an FEV 1 less than 60% constitutes a contraindication to performing research bronchoscopy (1). However, bronchoscopy in adults with asthma has been performed safely when the FEV 1 is lower, such as less than 50% predicted post-bronchodilator, and in patients with COPD (30,72,76) when the FEV 1 is less than 25% predicted prebronchodilator. Furthermore, in a single report, Martin and colleagues (22) demonstrated that bronchoscopy was safely performed in subjects with asthma with an FEV 1 less than 30% predicted.…”

“…This is also generally well tolerated, although changes in lung function have been reported (76). BAL does not significantly alter airway responsiveness, airflow limitation, and/or airway inflammation when BAL is incorporated into other procedures, such as bronchial biopsy, and segmental or whole lung allergen challenge (71,(76)(77)(78)80).…”