Delirium is associated with increased mortality, prolonged length of stay and development of post-ICU cognitive impairment in adult ICU patients. Strategies that may reduce the development or duration of delirium include avoiding drugs such as opioids and benzodiazepines, the use of light to moderate sedation, and early mobilization of the adult ICU patient. Sedation score is a major component of the CAM-ICU (Features 1 and 3).
Sedation score will affect the incidence of delirium as determined by the CAM-ICU
The data from the SEDCOM study (JAMA 2009;301:489) were evaluated to assess if the level of sedation measured by the RASS score (target of +1 to -2) was associated with delirium incidence as diagnosed by CAM-ICU. Delirium was assessed at baseline (BL), daily during double blind treatment (D1, D2, D3, etc), at end of treatment (ET), and 12, 24, and 48 hours after ET. RASS was assessed every 4 hours. The RASS score obtained within 15 minutes of the CAM-ICU was used to evaluate the relationship between sedation level and delirium.
The BL incidence of delirium by RASS score was 23.7% (RASS0), 80.6% (RASS1), 50.0% (RASS-1) and 81.1% (RASS-2). During the first 3 days of double-blind treatment, the incidence of delirium was 10.5-13.7% (RASS0), 60.0-78.6% (RASS1), 39.7-53.2% (RASS-1), and 68.7-80.6% (RASS-2). At and after ET, the incidence of delirium was 2.1-6.2% (RASS0), 41.7-44.4% (RASS1), 50.0-68.4% (RASS-1), and 59.3-82.4% (RASS-2).
For the target RASS level selected for the SEDCOM study, the incidence of delirium increased consistently as the level of sedation or agitation increased from the awake level. Additional study is required to explain whether this is related to diagnostic tool, sedation level itself, sedation drug, or some combination of these parameters.
Maine Medical Center
The Prince of Wales Hospital & University NSW