Inter-observer reliability of trained physiotherapists on the Functional Status Score for the Intensive Care Unit Chilean-Spanish version

Purpose: Evaluate inter-observer reliability of trained physiotherapists administering the Chilean-Spanish version of the Functional Status Score for the Intensive Care Unit (FSS-ICU). Methods: Six adult patients in a medical-surgical ICU were assessed and video-recorded by 1 of 2 expert physiotherapists. Twelve physiotherapists were then trained using recommended Spanish-language FSS-ICU materials. The 12 physiotherapists independently scored the FSS-ICU for the 6 video-recorded patients. Intraclass Correlation Coefficient (ICC) was used to evaluate the inter-observer reliability, and modified Bland-Altman plots evaluated agreement between the physiotherapists and experts. Results: This study was performed between May and August 2018. The FSS-ICU total score had a median score of 18 (range: 6 to 34) for the 6 patients. The ICC of the total score was 0.96 (95% CI, 0.92 to 1.00), and for each of the 5 individual FSS-ICU tasks, the ICC ranged between 0.87 and 0.92. The modified Bland–Altman plot revealed a mean difference of 0.6 (95% limits of agreement: −3.3 to 4.5). Conclusions: Twelve trained physiotherapists had excellent inter-observer reliability when administering the Chilean-Spanish FSS-ICU using videos of six critically ill patients, and had excellent agreement with an expert, revealing differences within the established minimal important difference. These findings provide new data supporting clinimetric properties of the Chilean-Spanish FSS-ICU.