Purpose: This study aimed to identify the early sedation depth in the first 48 hours of mechanical
ventilation and its relationship to clinical outcomes to promote the transition to light sedation.
Methods: This retrospective single-center cohort study was conducted in two medical intensive care
units (MICUs) at a general tertiary hospital, using a standardized sedation protocol. To investigate the
early sedation depth, the Sedation Index was used, which can indicate changes over the first 48 hours.
Patients were divided into three groups based on tertiles of Sedation Index. The primary outcome was
mortality at 30, 90, and 180 days. The secondary outcomes included length of stay in the ICU and
ventilator-free days. Kaplan-Meier analysis and multivariable Cox regression were conducted to compare
factors influencing mortality.
Results: This study included 394 patients. The deepest sedation group showed more severe illness,
delirium, and deeper sedation at admission (p < .001). The survival curve decreased as sedation
increased, even within the light sedation levels. In the deepest sedation group, 30-day mortality (hazard
ratio [HR] 2.11, 95% confidence interval [CI] 1.33e3.34), 90-day mortality (HR 2.00, 95% CI 1.31e3.06), and
180-day mortality (HR 1.77, 95% CI 1.17e2.67) increased. The length of stay in the ICU and ventilator-free
days did not show statistical differences.
Conclusions: These results indicate that early deep sedation is a modifiable factor that can potentially
affect mortality. The protocol for inducing the transition into light sedation must comply with recomꠓmendations to improve clinical outcomes.