Dexmedetomidine is indicated as a sedative agent in intensive care units(ICUs).While several clinical trials and two meta-analyses have compared this agent with propofol or midazolam,the results were variable depending on the specific end-point(e.g.,duration of mechanical ventilation,ICU mortality,maintaining a target depth of sedation,incidence of delirium episodes,length of hospital stay).Hence,the effectiveness of this new agent vs the comparators seems to be controversial.Trial sequential analysis(TSA)is a statistical technique that can estimate the optimal,cumulative number of patients that would be needed to generate a conclusive result.We therefore applied a TSA model to the most recent meta-analysis evaluating dexmedetomidine.A total of 10 randomized controlled trials were included in our analysis.According to our results,the comparison of dexmedetomidine vs propofol showed no proof of incremental effectiveness for the end-points of length of ICUs stay and incidence of delirium episodes.In contrast,futility(i.e.,proof of no incremental effectiveness)was demonstrated for the end-point of mechanical ventilation.Hence,the results for the comparison of dexmedetomidine vs propofol were inconclusive for the first two end-points;on the other hand,conclusiveness was reached for the third end-point.We conclude that the place of dexmedetomidine in therapy of critically ill patients is very uncertain and further controlled trials are still needed.