Gruenewald 2007.
| Methods | RCT, parallel design, single centre, University Hospital Schleswig‐Holstein, Kiel, Germany Duration of study period: not known; authors contacted, information not provided |
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| Participants | Total: 72 participants (only females) enrolled in the study Inclusion criteria: ASA physical status I‐ II participants undergoing laparoscopic gynaecological surgery lasting at least an hour Exclusion criteria: participants were excluded if they were pregnant, or there was any neuromuscular or neurological disease, or there was use of CNS‐active medication or abuse of alcohol or illicit drugs |
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| Interventions | 1. Standard practice group:(n = 35) (titration of general anaesthesia using routine clinical signs) 2. Entropy group: (n = 37) (propofol infusion adjusted to keep SE, values of between 40‐60) |
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| Outcomes | 1. Awareness assessed on 1st postoperative day 2. Assessing propofol consumption between the two groups 3. Time to awakening assessed |
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| Notes | Authors contacted for duration of study, but despite reply that author will "respond as soon as possible" no information sent despite repeated reminders | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Randomisation by opening sealed envelopes |
| Allocation concealment (selection bias) | Low risk | Sealed envelopes opened, but not specified if envelopes opaque |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | All participants had BIS & entropy electrodes applied to forehead prior to induction, irrespective of group; therefore blinded Entropy and BIS monitors screen obscured in standard practice group and entropy monitor visible in the entropy group |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Not mentioned, and unlikely it was done in view of the statement in the Discussion section where authors have written that "As entropy and standard practice guidance could not be performed in a blinded fashion, bias cannot be totally excluded" |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | All participants included in final analysis (37 assigned to entropy group and 35 to the standard practice group) |
| Selective reporting (reporting bias) | Low risk | All outcomes mentioned in methodology have been reported |
| Other bias | Unclear risk | Authors acknowledged GE Healthcare for supplying the M‐Entropy module and electrodes, but did not find decreased time to awakening in entropy group |