Longitudinal trajectories of sedation level and clinical outcomes in patients who are mechanically ventilated based on a group-based trajectory model: a prospective, multicentre, longitudinal and observational study in Korea

OBJECTIVES: Changes in sedation levels over a long time in patients who are mechanically ventilated are unknown. Therefore, we investigated the long-term sedation levels of these patients by classifying them into different longitudinal patterns. DESIGN: This was a multicentre, prospective, longitudinal, and observational study. SETTING: Twenty intensive care units (ICUs) spanning several medical institutions in Korea. PARTICIPANTS: Patients who received mechanical ventilation and sedatives in ICU within 48 hours of admission between April 2020 and July 2021. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary objective of this study was to identify the pattern of sedation practice. Additionally, we analysed the associations of trajectory groups with clinical outcomes as the secondary outcome. RESULTS: Sedation depth was monitored using Richmond Agitation-Sedation Scale (RASS). A group-based trajectory model was used to classify 631 patients into four trajectories based on sedation depth: persistent suboptimal (13.2%, RASS ≤ −3 throughout the first 30 days), delayed lightening (13.9%, RASS ≥ −2 after the first 15 days), early lightening (38.4%, RASS ≥ −2 after the first 7 days) and persistent optimal (34.6%, RASS ≥ −2 during the first 30 days). ‘Persistent suboptimal’ trajectory was associated with delayed extubation (HR: 0.23, 95% CI: 0.16 to 0.32, p<0.001), longer ICU stay (HR: 0.36, 95% CI: 0.26 to 0.51, p<0.001) and hospital mortality (HR: 13.62, 95% CI: 5.99 to 30.95, p<0.001) compared with ‘persistent optimal’. The ‘delayed lightening’ and ‘early lightening’ trajectories showed lower extubation probability (HR: 0.30, 95% CI: 0.23 to 0.41, p<0.001; HR: 0.72, 95% CI: 0.59 to 0.87, p<0.001, respectively) and ICU discharge (HR: 0.44, 95% CI: 0.33 to 0.59, p<0.001 and HR: 0.80, 95% CI: 0.65 to 0.97, p=0.024) compared with ‘persistently optimal’. CONCLUSIONS: Among the four trajectories, ‘persistent suboptimal’ trajectory was associated with higher mortality.