Table 2.

Number of retrieved papers for a literature search in the databases PubMed and EMBASE on participation in research bronchoscopy studies according to classification criteria

Classification criteria	PubMed	EMBASE
Total number retrieved	989	987
Non-English/non-Scandinavian language	102	None
Case studies/series	82	427
Secondary publications	116	108
Non-human studies	7	None
Participation not a major topic	674	443
Papers included in review	8	9
Papers common to PubMed and EMBASE searches	7

Secondary publications included reviews, expert panels, letters, guidelines, and so on. The EMBASE search excluded studies in languages other than English and Scandinavian languages, as well as non-human studies