Dexmedetomidine versus propofol sedation in reducing delirium among older adults in the ICU

BACKGROUND Delirium is common in the ICU, with incidence rates reported to be upwards of 70%. Due to the significant morbidity and mortality associated with delirium, it is hypothesised that a delirium-free sedative agent will improve outcomes in older adults admitted to the ICU. OBJECTIVES To assess if dexmedetomidine sedation is associated with a reduction in ICU delirium among older adults, and to evaluate its risks and benefits compared with propofol sedation. DESIGN Systematic review of randomised controlled trials and cohort studies with meta-analyses. DATA SOURCES Articles published from database inception to 8 April 2019 were retrieved from Medline, EMBASE, Evidence-based Medicine Reviews, International Pharmaceutical Abstracts, Scopus, ClinicalTrials.gov and WHO Trials. ELIGIBILITY Studies were included if they compared dexmedetomidine sedation with propofol in the ICU, reported the incidence of delirium as an outcome and had a mean/median sample age of at least 60. Studies that examined dexmedetomidine and propofol use intra-operatively or as part of general anaesthesia were excluded. RESULTS Dexmedetomidine sedation was associated with a lower incidence of delirium when compared with propofol: seven studies, n =1249; risk ratio 0.70; 95% confidence interval (CI) 0.52 to 0.95; P = 0.02. There was no statistically significant difference in the incidence of bradycardia: three studies, n =278; risk ratio 1.52; 95% CI 0.85 to 2.72; P = 0.16, and hypotension: six studies, n =867 patients; risk ratio 1.12; 95% CI 0.86 to 1.45; P = 0.42. Dexmedetomidine sedation did not reduce hospital length of stay, ICU length of stay or duration of mechanical ventilation compared with propofol. CONCLUSION Compared with propofol, dexmedetomidine sedation in the ICU is associated with lower delirium incidence among older adults with no significant increase in adverse events. In older adult ICU patients at risk of developing delirium, sedation with dexmedetomidine should be considered. Further research is warranted to elucidate and explain the mechanisms underlying this process, and to confirm our findings with large, multicentre trials. TRIAL REGISTRATION The study protocol has been registered in PROSPERO (CRD42018099339).