Development and validation of an objective assessment scale for chest tube insertion under ‘direct’ and ‘indirect’ rating

BACKGROUND: There is an increasing need for objective and validated educational concepts. This holds especially true for surgical procedures like chest tube insertion (CTI). Thus, we developed an instrument for objectification of learning successes: the assessment scale based on Objective Structured Assessment of Technical Skill (OSATS) for chest tube insertion, which is evaluated in this study. Primary endpoint was the evaluation of intermethod reliability (IM). Secondary endpoints are ‘indirect’ interrater reliability (IR) and construct validity of the scale (CV). METHODS: Every participant (N = 59) performed a CTI on a porcine thorax. Participants received three ratings (one ‘direct’ on site, two ‘indirect’ via video rating). IM compares ‘direct’ with ‘indirect’ ratings. IR was assessed between ‘indirect’ ratings. CV was investigated by subgroup analysis based on prior experience in CTI for ‘direct’ and ‘indirect’ rating. RESULTS: We included 59 medical students to our study. IM showed moderate conformity (‘direct’ vs. ‘indirect 1’ ICC = 0.735, 95% CI: 0.554–0.843; ‘direct’ vs. ‘indirect 2’ ICC = 0.722, 95% CI 0.533–0.835) and good conformity between ‘direct’ vs. ‘average indirect’ rating (ICC = 0.764, 95% CI: 0.6–0.86). IR showed good conformity (ICC = 0.84, 95% CI: 0.707–0.91). CV was proven between subgroups in ‘direct’ (p = 0.037) and ‘indirect’ rating (p = 0.013). CONCLUSION: Results for IM suggest equivalence for ‘direct’ and ‘indirect’ ratings, while both IR and CV was demonstrated in both rating methods. Thus, the assessment scale seems a reliable method for rating trainees’ performances ‘directly’ as well as ‘indirectly’. It may help to objectify and facilitate the assessment of training of chest tube insertion.