| Methods |
Design: 8 group parallel trial (incomplete 3 x 3 factorial design)
Purpose: examine the effect of open and hidden infusion of placebo on pain |
| Participants |
Patients: postoperative in‐patients (after removal of impacted third molars)
Baseline comparability: NS |
| Interventions |
Placebo: open infusion of vehicle by bedside investigator
Untreated: patient unaware of infusion of vehicle (either by machine or hidden investigator)
Experimental: infusions of naloxone and morphine (8 and 12 mg)
(Co‐intervention: NS) |
| Outcomes |
Pain (VAS) |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Adequate sequence generation? |
Unclear risk |
NS |
| Allocation concealment? |
Unclear risk |
NS |
| Blinding?
Treatment provider |
Low risk |
'Each patient was randomly assigned to receive, after surgery, a double‐blind injection...' |
| Blinding?
Outcome assessor |
Unclear risk |
Not relevant as patient reported outcome |
| Incomplete outcome data addressed?
All outcomes |
High risk |
Drop‐out > 15% or NS |
| Free of selective reporting? |
Unclear risk |
No protocol available |
| Free of other bias? |
Low risk |
|
| No signs of variance inequality or skewness? |
Unclear risk |
Not relevant (not naturally positive continuous outcomes e.g. change) |
| Trial size > 49? |
High risk |
N = 36 |
| Clearly concealed allocation + trial size > 49 + drop‐out max 15% |
High risk |
Trial size < 49 |
