The effect of age on clinical dose equivalency of fentanyl and morphine analgosedation in mechanically ventilated patients: Findings from the ANALGESIC trial

Remi-fent 1-A pragmatic randomised controlled study to evaluate the feasibility of using remifentanil or fentanyl as sedation adjuncts in mechanically ventilated patients

Objective

To evaluate the feasibility of conducting a prospective randomised controlled trial (pRCT) comparing remifentanil and fentanyl as adjuncts to sedate mechanically ventilated patients.

Design

Single-center, open-labelled, pRCT with blinded analysis.

Setting

Australian tertiary intensive care unit (ICU).

Participants

Consecutive adults between June 2020 and August 2021 expected to receive invasive ventilation beyond the next day and requiring opioid infusion were included. Exclusion criteria were pregnant/lactating women, intubation >12 h, or study-drug hypersensitivity.

Interventions

Open-label fentanyl and remifentanil infusions per existing ICU protocols.

Outcomes

Primary outcomes were feasibility of recruiting ≥1 patient/week and >90 % compliance, namely no other opioid infusion used during the study period. Secondary outcomes included complications, ICU-, ventilator- and hospital-free days, and mortality (ICU, hospital). Blinded intention-to-treat analysis was performed concealing the allocation group.

Results

208 patients were enrolled (mean 3.7 patients/week). Compliance was 80.6 %. More patients developed complications with fentanyl than remifentanil: bradycardia (n = 44 versus n = 21; p < 0.001); hypotension (n = 78 versus n = 53; p < 0.01); delirium (n = 28 versus n = 15; p = 0.001). No differences were seen in ICU (24.3 % versus 27.6 %,p = 0.60) and hospital mortalities (26.2 % versus 30.5 %; p = 0.50). Ventilator-free days were higher with remifentanil (p = 0.01).

Conclusions

We demonstrated the feasibility of enrolling patients for a pRCT comparing remifentanil and fentanyl as sedation adjuncts in mechanically ventilated patients. We failed to attain the study-opioid compliance target, likely because of patients with complex sedative/analgesic requirements. Secondary outcomes suggest that remifentanil may reduce mechanical ventilation duration and decrease the incidence of complications. An adequately powered multicentric phase 2 study is required to evaluate these results.