ABSTRACT
The first recorded use of bronchoscopy was in 1897, when Gustav Killian removed a pork bone from the right main bronchus (1). During the first two decades of the twentieth century Chevalier Jackson developed the rigid bronchoscope, which remains in use today for surgical bronchoscopy. In the 1970s and 1980s, the rigid bronchoscope was used in pioneering work by Finnish investigators to obtain the fJTSt mucosal biopsy samples from patients with asthma (2). However, it was only with the advent of the fiberoptic bronchoscope that it became possible to sample the airways without the need for a general anesthetic, and with acceptable levels of inconvenience and discomfort for research volunteers. Since the mid-1980s, many investigators have carried out bronchoscopy in patients with asthma and have used bronchoalveolar lavage (BAL) and bronchial biopsy to obtain samples from the asthmatic airway. It has even been suggested that bronchoscopy can be considered as a routine investigation in asthma (3), although in most centers it remains a research tool only. Bronchoscopic biopsy in asthma has yielded a large amount of information about the histological characteristics of mild and moderate disease, and increasingly studies are being performed in severe asthma. In combining bronchoscopy with exposure to allergen,
11. Safety Issues As with any research procedure, the safety and rights of the subject are paramount. Several studies involving bronchoscopy have been published demonstrating that complications are rare if patients are appropriately selected and the procedures are performed by skilled investigators {4,5). Broadly speaking, patients should be carefully characterized before bronchoscopy and should have stable disease at the time of investigation. Many investigators premedicate asthmatic subjects with nebulized bronchodilators prior to bronchoscopy to try to reduce the degree of postprocedure brochospasm, although in subjects with mild asymptomatic asthma this step can be omitted if the bronchodilator drug may interfere with mediator release and its subsequent analysis. Generous use of topical anesthesia helps to reduce the amount of coughing that is induced by bronchoscopy; thus, it may help to attenuate procedure-related bronchospasm. Nevertheless it is important not to exceed the safe dose of lignocaine (lidocaine) to prevent potential serious side effects. Monitoring of oxygen saturation is mandatory, and most investigators give supplementary oxygen (usually by nasal cannula) throughout the procedure. Opinion varies as to the advantages of using the oral or the nasal route of oxygen delivery for research bronchoscopy. Nasal cannulae can be fixed better in the nose but can also be hooked into the mouth, whereas the nasal route, traditionally preferred for clinical diagnostic bronchoscopies, offers greater stability of the bronchoscope, which can help speed the procedure. Against this, the nasal approach is more likely to cause upper airway bleeding, which may contaminate the BAL samples.
