Effect of sedation medication and daily awakening on delirium in the mechanically ventilated critically ill patient: a descriptive pilot study

Purpose: Sedative medications appear to be the leading iatrogenic cause of delirium.  Although daily awakenings are recommended in mechanically ventilated patients, evidence of delirium reduction is lacking.  This study will determine if there are differences in delirium, days ventilated, and intensive care unit (ICU) length of stay (LOS) between lorazepam, propofol, dexmedetomidine, and fentanyl when concurrently receiving daily awakenings. 

Methods: An Institutional review board approved prospective, randomized, open-label, pilot-study.  Medical ICU patients with informed consent were enrolled if mechanical ventilation was planed for over 24 hours.  Patients were excluded for severe neurological deficits, alcohol dependency, chronic benzodiazepine usage, advanced airway modalities, acute myocardial infarction, heart rate under 50 beats per minute, mean arterial pressure less than 65mmHg, or inability to be randomized within 48 hours of intubation.  Subjects were randomized to lorazepam, propofol, dexmedetomidine, or fentanyl.  Subjects underwent daily wakenings and were assessed for delirium.  Primary outcomes were incidence of delirium with daily awakenings and between the four treatment arms in the setting of daily awakenings.  Secondary outcomes included difference in days ventilated and ICU LOS.  Scheffe post-hoc analysis of variance and one-sample T test were utilized. 

Results: Incidence of delirium was higher with propofol versus dexmedetomidine (78.5percent versus 5percent, P-value 0.025).  Time ventilated was not different between treatment arms (P-value 0.685); nor was the ICU LOS (P-value 0.646).  There was less delirium (-40.5percent; 95percent CI, -61.9percent to -19.1percent, P-value 0.001), and fewer days in the ICU (-3.11days; 95percent CI, -4.77days to -1.46days, P-value 0.001) with daily awakenings versus historical controls.

Conclusion: Dexmedetomidine has a lower incidence of delirium compared to propofol.  However, the average times spent mechanically ventilated and in the ICU are equivalent between lorazepam, propofol, dexmedetomidine, and fentanyl with daily awakenings.  The daily awakening process decreases the incidence of delirium and ICU LOS compared to historical data.