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Background: Electromagnetic navigation bronchoscopy (ENB) is a relatively new and technically demanding procedure for the guidance of bronchoscopic biopsy to help locate small lung lesions. The results in experienced hands are well described. However, we do not know the results in unexperienced hands-in other words, we have no knowledge about how fast you can learn the procedure.Aim: The aim of this study was to draw learning curves for beginners in ENB using Cumulated Sum (CUSUM) analysis, a method for quantitative evaluation of the learning curves for clinical procedures.Methods: Four operators from 3 centers without prior ENB experience were enrolled. The outcome of consecutive ENB procedures was assessed and classified as either diagnostic or nondiagnostic based on sample adequacy. Learning curves were drawn based on diagnostic yield.Results: A total of 215 procedures were assessed. For 2 of the operators (operators 1 and 4), at least 25 to 30 procedures were necessary to obtain competency whereas operators 2 and 3 showed more horizontal learning curves indicating an overweight of diagnostic procedures from the beginning.Conclusion: Operators achieve competences in ENB at different paces. This must be taken in account when beginners start to learn the procedure. There is a huge need for a structured educational program and a validated test to determine competences.

Background Investigating disease mechanisms and treatment responses in obstructive airway diseases with invasive sampling are hampered by the small size and mechanical artefacts that conventional forceps biopsies suffer from. Endoscopic cryobiopsies are larger and more intact and are being increasingly used. However, the technique has not yet been explored for obtaining mucosa biopsies. Objective To investigate differences in size and quality of endobronchial mucosal biopsies obtained with cryotechnique and forceps. Further, to check for eligibility of cryobiopsies to be evaluated with immunohistochemistry and in situ hybridization and to investigate tolerability and safety of the technique. Methods Endobronchial mucosal biopsies were obtained with cryotechnique and forceps from patients with haemoptysis undergoing bronchoscopy and evaluated by quantitative morphometry, automated immunohistochemistry and in situ hybridization. Results A total of 40 biopsies were obtained from 10 patients. Cross‐sectional areas were threefold larger in cryobiopsies (median: 3.08 mm2 (IQR: 1.79) vs 1.03 mm2 (IQR: 1.10), P < 0.001). Stretches of intact epithelium were 8‐fold longer (median: 4.61 mm (IQR: 4.50) vs 0.55 mm (IQR: 1.23), P = 0.001). Content of glands (median: 0.095 mm2 (IQR: 0.30) vs 0.00 mm2 (IQR: 0.01), P = 0.002) and airway smooth muscle (median: 0.25 mm2 (IQR: 0.30) vs 0.060 mm2 (IQR: 0.11), P = 0.02) was higher in the cryobiopsies compared with forceps biopsies. Further, the cryobiopsies had well‐preserved protein antigens and mRNA. Mild to moderate bleeding was the only complication observed. Conclusion and clinical relevance By yielding significantly larger and more intact biopsies, the cryotechnique represents a valuable new research tool to explore the bronchi in airway disease. Ultimately with the potential to create better understanding of underlying disease mechanisms and improvement of treatments.

BackgroundIn vivo studies of airway pathology in obstructive lung disease are limited by poor quality of specimens obtained with forceps. Obtainment of cryobiopsies has increased diagnostic yield in cancer and interstitial lung disease but has not been used in patients with asthma. In a recent pilot study, we found mucosal cryobiopsies to be larger and more intact than conventional forceps biopsies.Aims and ObjectivesTo compare quality and safety of mucosal cryobiopsies versus conventional forceps biopsies in patients with asthma.MethodsEndobronchial biopsies were obtained with forceps and cryoprobe from patients with asthma not currently treated with inhaled steroids and evaluated histologically.ResultsA total of 240 cryobiopsies and 288 forceps biopsies were obtained from 48 patients. Bleeding from the biopsy site was common but self-limiting. No major complications related to the procedure were seen. Cryobiopsy cross areas were 4 times larger compared with forceps. Stretches of intact epithelium were detected in in all cryobiopsies compared to 33% in forceps biopsies. Further, the length of intact epithelium was on average 4 times longer in the cryobiopsies. Importantly, there was a good preservation of both antigens and mRNA in the cryobiopsies ensuring a suitability and robustness for immunohistochemistry and in-situ hybridisation.ConclusionObtainment of mucosal cryobiopsies in patients with asthma is safe and yields biopsies that are significantly larger and morphologically better preserved compared with traditional forceps biopsies. The cryotechnique thus seems to be a promising tool for future in vivo studies of airway pathology.

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