A double-blinded randomized evaluation of alfentanil and morphine vs fentanyl: analgesia and sleep trial (DREAMFAST)

Patients using fentanyl patient-controlled analgesia (PCA), the standard first-line choice in our hospitals, commonly complain of postoperative sleep disruption due to pain. The aim of this study was to determine whether the PCA combination of alfentanil and morphine, which provides longer analgesia without compromising onset speed, would improve postoperative pain-related sleep interference.

Two hundred and twelve adults undergoing major surgery where PCA was the planned principal postoperative analgesic modality were randomized to either the combination of alfentanil and morphine (Group AM) or fentanyl (Group F). The primary outcome was pain-related awakenings during the second postoperative night as measured by the study questionnaire, based on the St Mary's Hospital Sleep Questionnaire. Analgesic efficacy, other sleep measures, and opioid-related side-effects were also assessed.

There was no difference in pain-related sleep disturbance between the groups, with 41% of Group AM and 53% of Group F waking due to pain (P=0.10). Group AM had better rest and dynamic analgesia in the first 24 h with fewer requiring rescue ketamine infusion during the 2 day study period (2 vs 14%, P=0.001). Those in Group AM experienced less nausea and vomiting in the second 24 h (18 vs 35%, P=0.028) but more pruritus (40 vs 23%, P=0.013).

Despite better early postoperative analgesia, pain-related sleep interference was not improved by the PCA combination of alfentanil and morphine. AUSTRALIAN NEW ZEALAND CLINICAL TRIALS REGISTRY: Ref: ACTRN12608000118303.