BACKGROUNDThe aim of this study was to assess the impact on mechanical ventilation and ICU outcomes of substituting remifentanil for sufentanil, in an analgesia-based sedation protocol. A database of data prospectively collected was retrospectively analyzed. The study was carried out in a 16-bed tertiary-care ICU.METHODSThe study included 1544 mechanically ventilated patients admitted from January 2001 to December 2006. Patients were compared between two consecutive phases. Analgesia-based sedation guidelines were the same, except for the opiate used. The patient-to-nurse ratio (2.5) and ventilator weaning practices remained unchanged. 794 patients were included during the sufentanil phase, and 750 during the remifentanil phase. Remifentanil was associated with significantly less time spent on mechanical ventilation (10 days[3-21] vs. 14 days[3-27], P<0.01) and in the ICU (16 days[3-22] vs. 19 days[4-26], P<0.01). The difference was significant for patients ventilated no longer than four days (P=0.0035) but not for patients ventilated more than four days (P=0.058). Sedation target on the Ramsay scale was reached more often with remifentanil. The use and amount of hypnotic agents in addition to the opiate were significantly lower with remifentanil. The cost of analgesia-based sedation was similar in the sufentanil and the remifentanil group.CONCLUSIONOur study suggests that using a short-acting opiate with short context-sensitive half-life in an analgesia-based sedation protocol may significantly decrease the duration of mechanical ventilation and the ICU length of stay even though not significantly in long term sedation, while improving the achievement of sedation goals despite a lower requirement for adjunctive hypnotic agents, with no additional costs.